Preparation method of novel high-density ITO target material

Abstract

The invention relates to the field of target material manufacturing, in particular to a preparation method of a novel high-density ITO target material. The preparation method comprises the following steps: mixing indium oxide powder and tin oxide powder which are uniform in granularity, granulating, performing cold isostatic pressing, and sintering to obtain the high-density ITO target material. The surface affinity of the indium oxide powder and the tin oxide powder is utilized, an adhesive and a dispersing agent do not need to be added in the granulation process, and meanwhile degreasing is not needed in the subsequent preparation process. According to the method, the surface affinity between indium oxide and tin oxide is creatively utilized, the technological process is reduced, degreasing is not needed, the production efficiency is improved, the preparation cost is saved, and the prepared ITO target material is high in density, stable in quality and capable of being applied to industrial production on a large scale.

Description

[0001] This application is a divisional application of the following application: the application date is August 9, 2018, the application number is 201810901538.8, and the patent name is a new method for preparing high-density ITO target materials. Technical Field

[0002] The invention relates to the technical field of ITO target materials, and more specifically, to a method for preparing a novel high-density ITO target material. Background Art

[0003] ITO film is an n-type semiconductor material with high conductivity, high visible light transmittance, high mechanical hardness and good chemical stability. It is the most commonly used thin film material for transparent electrodes of liquid crystal displays (LCD), plasma displays (PDP), electroluminescent displays (EL / OLED), touch panels (Touch Panel), solar cells and other electronic instruments. In particular, with the large-scale LCD TVs (FPD) and the large-scale vacuum sputtering production lines, the demand for ITO is increasing, and the density of the target material is becoming higher and higher. In order to reduce the downtime of the production line and avoid the occurrence of extinguishing, most manufacturers require the density of ITO targets to be above 99.5%.

[0004] The material of ITO film is tin-doped indium oxide. The most advanced ITO target material manufacturing process popular in the world is: powder making - mixing - adding binder and dispersant to granulate - compression molding - cold isostatic press (CIP) - degreasing - sintering - machining - binding - flaw detection - inspection - packaging - shipping. Among them, there are two types of sintering: atmospheric oxygen sintering and pressurized oxygen sintering. The earlier generation of technology, the casting molding process is also used by some manufacturers. However, since harmful substances such as binders and dispersants are added during granulation, it is necessary to degrease at a medium temperature of 600 degrees before sintering to remove the binder and dispersant, and the degreasing time is long, generally about 5 days, and the investment cost of the degreasing furnace is high, which greatly increases the investment cost. A method for preparing a high-density ITO evaporation target material is disclosed in the Chinese invention patent with the authorization announcement number CN102731067B. The process steps include powder preparation, mixing, fat addition, granulation, molding, degreasing and sintering. During the granulation process, due to the poor bonding performance of indium oxide and tin oxide, adhesives and dispersants need to be added to make indium oxide and tin oxide bond together. More adhesives and dispersants will affect the density and other properties of ITO targets, so before sintering, degreasing must be performed at a temperature of 600°C to remove the adhesive and dispersant. The degreasing process takes a long time, and the investment cost of the degreasing furnace is high, which greatly increases the production cost of ITO targets. Summary of the invention

[0005] In view of the shortcomings of the ITO target material preparation technology in the prior art, the purpose of the present invention is to provide a novel method for preparing a high-density ITO target material. The preparation method does not require the addition of additives such as adhesives and dispersants during the granulation process, omits the degreasing step, and has a simple process flow; the prepared ITO target material has high density and stable quality.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A novel ITO target preparation method comprises the following steps:

[0008] S1. Selecting indium oxide powder and tin oxide powder of uniform particle size and wet mixing, wherein the particle size of the indium oxide powder is larger than the particle size of the tin oxide powder, and granulating at 20 to 80 ° C to obtain ITO powder;

[0009] S2. The ITO powder prepared in step S1 is screened through a vibrating sieve to remove lumps;

[0010] S3. The ITO particles processed in step S2 are placed into a mold and pressed in a cold isostatic press to obtain an ITO blank;

[0011] S4. The ITO blank prepared in step S3 is placed in a sintering furnace and sintered in an oxygen atmosphere to obtain an ITO target;

[0012] S5. Mechanically process the ITO target prepared in step S4 into a desired size.

[0013] Furthermore, in the granulation process in step S1, the moisture content of the ITO powder is controlled at 2-6%.

[0014] Furthermore, the mass fraction ratio of indium oxide to tin oxide powder used in step S1 is 90-97:3-10.

[0015] Preferably, the temperature during granulation in step S1 is 50°C.

[0016] The particle size of the indium oxide powder used in the present invention is larger than that of the tin oxide powder. At the same time, the reaction temperature during the granulation process is strictly controlled at 20-80° C. The above conditions can adjust the surface affinity between indium oxide and tin oxide to the best, so there is no need to add adhesives and dispersants during the granulation process in step S1.

[0017] Furthermore, the pressure of the cold isostatic pressing in step S3 is 200-350 MPa.

[0018] The present invention directly adopts cold isostatic pressing when pressing the ITO blank, eliminating the process step of pre-pressing. At the same time, due to the surface affinity between the indium oxide powder and the tin oxide powder, no adhesive needs to be added in the cold isostatic pressing, thus simplifying the process steps.

[0019] Furthermore, the sintering process parameters in step S4 are as follows: temperature: 1350-1700° C., time: 24-120 hours.

[0020] In step S5, the ITO target is machined into different sizes according to the actual needs of the customer to facilitate subsequent transportation and use.

[0021] A high-density ITO target material obtained by the above preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention utilizes the surface affinity between indium oxide powder and tin oxide powder, thereby realizing a granulation process without adding adhesives and dispersants. Since no adhesives and dispersants are added, the degreasing process is omitted in the subsequent process. In actual production, there is no need to set up a degreasing furnace, which can effectively reduce the production cost of ITO target materials and improve economic benefits.

[0024] The ITO target material preparation method provided by the present invention does not require the addition of adhesives and dispersants, thus saving the production cost of the ITO target material. At the same time, the residue of adhesives and dispersants in the ITO target material is eliminated, which can greatly improve the product density and the performance of the ITO target material product, and can obtain a large-scale ITO target material with a stable density of more than 99.8%. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with the embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0026] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0028] Example 1

[0029] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0030] S1. The indium oxide powder having a particle size of 0.5 μm and the tin oxide powder having a particle size of 50 nm were wet mixed in a mass fraction ratio of 90:10, the moisture content of the powder was 2%, and the mixture was uniformly mixed and granulated at 50 ° C to obtain ITO powder;

[0031] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0032] S3. The ITO particles processed in step S2 are loaded into a mold and cold isostatically pressed at a pressure of 350MPa to obtain an ITO blank;

[0033] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1620° C. for 48 hours. After sintering, an ITO target is obtained.

[0034] After testing, the density of the ITO target prepared in Example 1 is 99.97%.

[0035] Example 2

[0036] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0037] S1. The indium oxide powder having a particle size of 72 μm and the tin oxide powder having a particle size of 0.1 μm were wet mixed in a mass fraction ratio of 90:10, the moisture content of the powder was 4%, and after mixing evenly, granulation was performed at 50 ° C to obtain ITO powder;

[0038] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0039] S3. The ITO particles processed in step S2 are loaded into a mold and cold isostatically pressed at a pressure of 300 MPa to obtain an ITO blank;

[0040] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1550° C. for 60 hours. After the sintering is completed, an ITO target is obtained.

[0041] After testing, the density of the ITO target prepared in Example 2 is 99.82%.

[0042] Example 3

[0043] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0044] S1. The indium oxide powder having a particle size of 80 μm and the tin oxide powder having a particle size of 0.3 μm were wet mixed in a mass fraction ratio of 92:8, the moisture content of the powder was 6%, and the mixture was uniformly mixed and granulated at 80 ° C to obtain ITO powder;

[0045] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0046] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 320 MPa to obtain an ITO blank;

[0047] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1550° C. for 60 hours. After the sintering is completed, an ITO target is obtained.

[0048] After testing, the density of the ITO target prepared in Example 3 is 99.86%.

[0049] Example 4

[0050] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0051] S1. The indium oxide powder having a particle size of 25 μm and the tin oxide powder having a particle size of 0.3 nm were wet mixed in a mass fraction ratio of 94:6, the moisture content of the powder was 6%, and the mixture was uniformly mixed and granulated at 60 ° C to obtain ITO powder;

[0052] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0053] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 300 MPa to obtain an ITO blank;

[0054] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1540° C. for 40 hours. After the sintering is completed, an ITO target is obtained.

[0055] After testing, the density of the ITO target prepared in Example 4 is 99.94%.

[0056] Example 5

[0057] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0058] S1. The indium oxide powder having a particle size of 40 μm and the tin oxide powder having a particle size of 6.5 μm were wet mixed in a mass fraction ratio of 96:4, the moisture content of the powder was 2%, and the mixture was uniformly mixed and granulated at 40 ° C to obtain ITO powder;

[0059] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0060] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 250MPa to obtain an ITO blank;

[0061] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1480° C. for 60 hours. After the sintering is completed, an ITO target is obtained.

[0062] After testing, the density of the ITO target prepared in Example 5 is 99.83%.

[0063] Example 6

[0064] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0065] S1. The indium oxide powder having a particle size of 75 μm and the tin oxide powder having a particle size of 10 nm were wet mixed in a mass fraction ratio of 97:3, the moisture content of the powder was 2%, and the mixture was uniformly mixed and granulated at 20 ° C to obtain ITO powder;

[0066] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0067] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 220 MPa to obtain an ITO blank;

[0068] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1420° C. for 80 hours. After the sintering is completed, an ITO target is obtained.

[0069] After testing, the density of the ITO target prepared in Example 6 is 99.81%.

[0070] Example 7

[0071] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0072] S1. The indium oxide powder having a particle size of 50 μm and the tin oxide powder having a particle size of 30 μm were wet mixed in a mass fraction ratio of 97:3, the moisture content of the powder was 6%, and the mixture was uniformly mixed and granulated at 50 ° C to obtain ITO powder;

[0073] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0074] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 200 MPa to obtain an ITO blank;

[0075] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1700° C. for 24 hours. After sintering, an ITO target is obtained.

[0076] After testing, the density of the ITO target prepared in Example 7 is 99.85%.

[0077] Example 8

[0078] This embodiment provides a method for preparing a high-density ITO target material, comprising the following steps:

[0079] S1. The indium oxide powder having a particle size of 20 μm and the tin oxide powder having a particle size of 15 μm were wet mixed in a mass fraction ratio of 90:10, the moisture content of the powder was 4%, and after mixing evenly, granulation was performed at 50 ° C to obtain ITO powder;

[0080] S2. The ITO powder prepared in step S1 is passed through a vibrating sieve to remove lumps, and the mesh size is 200 mesh;

[0081] S3. The ITO particles processed in step S2 are cold isostatically pressed at a pressure of 300 MPa to obtain an ITO blank;

[0082] S4. Put the ITO blank processed in step S3 into a sintering furnace and sinter it in an oxygen atmosphere at a temperature of 1350° C. for 120 hours. After the sintering is completed, an ITO target is obtained.

[0083] After testing, the density of the ITO target prepared in Example 8 is 99.93%.

[0084] Comparative Example 1

[0085] This comparative example refers to the steps of Example 1 to provide a method for preparing a high-density ITO target. The difference from Example 1 is that the particle sizes of the indium oxide powder and the tin oxide powder are the same, both of which are 20 μm.

[0086] After testing, the density of the ITO target prepared in Comparative Example 1 is 99.30%.

[0087] Comparative Example 2

[0088] This comparative example refers to the steps of Example 1 to provide a method for preparing a high-density ITO target material. The difference from Example 1 is that the particle size of the indium oxide powder is 20 μm, and the particle size of the tin oxide powder is 30 μm.

[0089] After testing, the density of the ITO target prepared in Comparative Example 2 was 99.26%.

[0090] Comparative Example 3

[0091] This comparative example refers to the steps of Example 1 to provide a method for preparing a high-density ITO target material. The difference from Example 1 is that the granulation temperature in step S1 is 15°C.

[0092] After testing, the density of the ITO target prepared in Comparative Example 3 is 99.31%.

[0093] Comparative Example 4

[0094] This comparative example refers to the steps of Example 1 to provide a method for preparing a high-density ITO target material. The difference from Example 1 is that the granulation temperature in step S1 is 90°C.

[0095] After testing, the density of the ITO target prepared in Comparative Example 4 is 99.48%.

[0096] From the analysis of Comparative Examples 1 to 4, it can be seen that the density of the ITO target prepared in Comparative Examples 1 to 4 is low and cannot meet the production needs. The reasons are as follows: In the method for preparing a high-density ITO target provided by the present invention, the particle size relationship between the indium oxide powder and the tin oxide powder and the temperature during the granulation process need to be strictly controlled. The powder particle size and granulation temperature determine the surface affinity between the indium oxide powder and the tin oxide powder, which affects the granulation effect and the density of the finished ITO target.

[0097] Obviously, the above embodiments are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A new method for preparing high-density ITO target material. It is characterized in that The following steps are involved: S1. Selecting indium oxide powder and tin oxide powder of uniform particle size and wet mixing, wherein the particle size of the indium oxide powder is larger than the particle size of the tin oxide powder, and granulating at 20 to 80 ° C to obtain ITO powder; S2. The ITO powder prepared in step S1 is screened through a vibrating sieve to remove lumps; S3. The ITO particles processed in step S2 are placed into a mold and pressed in a cold isostatic press to obtain an ITO blank; S4. The ITO blank prepared in step S3 is placed in a sintering furnace and sintered in an oxygen atmosphere to obtain an ITO target; S5. The ITO target prepared in step S4 is mechanically processed into a desired size; Wherein, the moisture content of ITO powder is controlled at 2-6% during the granulation process of step S1, and no adhesive and dispersant are added during the granulation process of step S1; The subsequent steps S2 to S5 do not include a degreasing process.

2. The method for preparing a novel high-density ITO target material as claimed in claim 1, It is characterized in that The granulation temperature in step S1 is 50 to 60°C.

3. The method for preparing a novel high-density ITO target material as claimed in claim 2, It is characterized in that The granulation temperature in step S1 is 50 or 60°C.

4. The method for preparing a novel high-density ITO target material as claimed in claim 1, It is characterized in that The particle size of the indium oxide powder used in step S1 is 0.5 μm to 80 μm, and the particle size of the tin oxide powder is 0.3 nm to 30 μm.

5. The method for preparing a novel high-density ITO target material as claimed in claim 1, It is characterized in that The mass fraction ratio of indium oxide to tin oxide powder used in step S1 is 90-97:3-10.

6. The method for preparing a novel high-density ITO target material according to claim 1, It is characterized in that In step S2, the mesh size of the vibrating screen is 200 meshes.

7. The method for preparing a novel high-density ITO target material according to claim 1, It is characterized in that The pressure of the cold isostatic pressing in step S3 is 200-350 MPa.

8. The method for preparing a novel high-density ITO target material as claimed in claim 1, It is characterized in that The cold isostatic pressing in step S3 does not add any adhesive.

9. The method for preparing a novel high-density ITO target material as claimed in claim 1, It is characterized in that The sintering process parameters in step S4 are as follows: temperature is 1350-1700° C., and time is 24-120 hours.

10. An ITO target material obtained by the preparation method according to any one of claims 1 to 9.