Pad burning mode for greatly reducing deformation of sintered bottom of ITO rotating target material

Abstract

The invention relates to the technical field of target materials, in particular to a pad burning mode for greatly reducing deformation of the sintered bottom of an ITO rotating target material. The pad sintering mode for greatly reducing the deformation of the sintered bottom of the ITO rotating target material is specifically as follows: an ITO blank is fixed on a base station of a sintering furnace for sintering, the base station comprises a silicon carbide cross beam and a composite gasket, the composite gasket is arranged on the silicon carbide cross beam, and the composite gasket sequentially comprises graphite paper and a porous zinc oxide gasket from top to bottom. The finished target obtained through the backing firing mode is high in density and extremely low in deformation quantity, cracks do not appear on the surface of the target, and a new thought is provided for backing firing of the target.

Description

Technical Field

[0001] The present invention relates to the technical field of target materials, and in particular to a pad firing method for significantly reducing the deformation of the bottom of an ITO rotating target material during sintering. Background Art

[0002] Indium tin oxide (ITO) is a target material used for magnetron sputtering coating. It is used to coat transparent conductive ITO film with high conductivity (resistivity ≤ 1×10 -4 Ω·cm), high light transmittance (visible light transmittance > 85%) and high chemical stability (acid and alkali corrosion resistance), and are mainly used in the display industry, such as: liquid crystal screen (LCD), organic light emitting diode (OLED) transparent electrodes; photovoltaic field: transparent conductive layer of thin-film solar cells and smart glass industry.

[0003] The sintering temperature of ITO target is usually above 1550℃. During long-term sintering, chemical diffusion or physical adhesion is likely to occur when the target is in direct contact with the setter plate, making it difficult to separate or even damaged. Therefore, a gasket needs to be added between the target and the setter plate to protect the quality of the finished ITO target.

[0004] Patent technical document CN116854485B discloses a sintering process method for increasing the strength of indium tin oxide target material. The invention uses silicon carbide beams + alumina gaskets to replace traditional alumina support plates + alumina gaskets, and uses gradient temperature sintering. The final prepared indium tin oxide target material has a tensile strength of up to 166.89 MPa, no internal abnormalities and a production yield of more than 90%.

[0005] However, traditional alumina gaskets often do not match the thermal expansion coefficient of ITO, which leads to increased stress and causes certain deformation of the ITO sintered product. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to propose a pad firing method that significantly reduces the deformation of the bottom of the ITO rotating target during sintering, so as to solve the problem that the traditional pad firing method easily causes the deformation of the bottom of the ITO rotating target due to silver sintering.

[0007] Based on the above objectives, the present invention provides a pad firing method that significantly reduces the deformation of the bottom of the ITO rotating target during sintering. The pad firing method is as follows: the ITO blank is fixed on the base of the sintering furnace for sintering, and the base is a silicon carbide beam and a composite gasket. The composite gasket is placed on the silicon carbide beam, and the composite gasket is composed of graphite paper and porous zinc oxide gasket from top to bottom.

[0008] The pore size of the porous zinc oxide gasket is 50-100 μm.

[0009] Preferably, the specific steps of the pad firing are as follows: the ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering, the base is a silicon carbide beam and a composite gasket placed on the beam, and the sintering is performed in a gradient heating manner, 200-700°C, the heating rate is 0.08-0.1°C / min, 700-1580°C, the heating rate is 0.25-0.3°C / min, after reaching the sintering temperature, the temperature is kept warm, and the temperature is lowered after the sintering is completed, the cooling rate is 0.4°C / min, and when the temperature in the furnace is 10-20°C, the hearth is lowered to obtain the ITO rotary target.

[0010] Preferably, the purity of the silicon carbide beam is ≥98%, the temperature resistance is ≥1700°C, and the compressive strength is 500-700Mpa.

[0011] Preferably, the purity of the porous zinc oxide gasket is ≥98%.

[0012] Preferably, the thickness of the graphite paper is 0.1-0.2 mm.

[0013] Preferably, the steps for preparing the ITO blank are as follows:

[0014] S1: Add indium oxide powder, tin oxide powder and pure water into a ball mill and ball mill to obtain ITO slurry;

[0015] S2: spray granulating the ITO slurry to obtain ITO powder;

[0016] S3: Pre-pressing the ITO powder to obtain a blank;

[0017] S4: The primary blank is subjected to cold isostatic pressing to obtain an ITO blank.

[0018] Preferably, the weight ratio of the indium oxide powder to the tin oxide powder in step S1 is 97:3.

[0019] Preferably, the ball milling time in step S1 is 24-48 hours.

[0020] Preferably, the air inlet temperature of the spray granulation in step S2 is 200-230°C, and the air outlet temperature is 80-100°C.

[0021] Preferably, the spray granulation in step S2 is performed in a centrifugal spray granulator.

[0022] Preferably, the molding pressure of the primary pre-pressing molding in step S3 is 200-500 Kgf / cm 2 , the holding time is 5-20min.

[0023] Preferably, in the cold isostatic pressing in step S4, the molding pressure is 250-300 MPa, and the holding time is 30-60 min.

[0024] Beneficial effects of the present invention:

[0025] The ITO target material obtained by the pad firing method of the present invention has high density and extremely low deformation, and no cracks appear on the surface of the target material.

[0026] By using a composite gasket formed by porous zinc oxide gasket and graphene, the deformation of the target material obtained by sintering is significantly improved compared with the traditional aluminum oxide gasket. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0028] Example 1:

[0029] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 24 h to obtain an ITO slurry;

[0030] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 200°C and an outlet air temperature of 80°C to obtain ITO powder;

[0031] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 200 kgf / cm 2 , the holding time is 5 minutes, and a green embryo is obtained;

[0032] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 250 MPa and a holding time of 30 min to obtain an ITO blank;

[0033] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and a composite gasket. The composite gasket is placed on the silicon carbide beam. The upper layer of the composite gasket is a porous zinc oxide gasket with a pore size of 50-100 μm, and the lower layer is a graphite paper with a thickness of 0.1 mm. Gradient heating is used for sintering. At 200-700°C, the heating rate is 0.08°C / min, and at 700-1580°C, the heating rate is 0.25°C / min. After reaching the sintering temperature, the temperature is kept constant. After sintering, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace is 10°C, the furnace bed is lowered to obtain an ITO rotating target.

[0034] Example 2:

[0035] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 30 h to obtain an ITO slurry;

[0036] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 210°C and an outlet air temperature of 90°C to obtain ITO powder;

[0037] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 300 kgf / cm 2 , the holding time is 10 minutes, and a green embryo is obtained;

[0038] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 270 MPa and a holding time of 50 min to obtain an ITO blank;

[0039] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and a composite gasket. The composite gasket is placed on the silicon carbide beam. The upper layer of the composite gasket is a porous zinc oxide gasket with a pore size of 50-100 μm, and the lower layer is a graphite paper with a thickness of 0.2 mm. Gradient heating is used for sintering. At 200-700°C, the heating rate is 0.09°C / min, and at 700-1580°C, the heating rate is 0.29°C / min. After reaching the sintering temperature, the temperature is kept constant. After sintering, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace is 15°C, the furnace bed is lowered to obtain an ITO rotating target.

[0040] Example 3:

[0041] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 48 h to obtain an ITO slurry;

[0042] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 230°C and an outlet air temperature of 100°C to obtain ITO powder;

[0043] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 500 kgf / cm 2 , the holding time is 20 minutes, and a green embryo is obtained;

[0044] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 300 MPa and a holding time of 60 min to obtain an ITO blank;

[0045] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and a composite gasket. The composite gasket is placed on the silicon carbide beam. The upper layer of the composite gasket is a porous zinc oxide gasket with a pore size of 50-100 μm, and the lower layer is a graphite paper with a thickness of 0.2 mm. Gradient heating is used for sintering. At 200-700°C, the heating rate is 0.1°C / min, and at 700-1580°C, the heating rate is 0.3°C / min. After reaching the sintering temperature, the temperature is kept constant. After sintering, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace is 20°C, the furnace bed is lowered to obtain an ITO rotating target.

[0046] Comparative Example 1: The difference from Example 2 is that the gasket is a zinc oxide gasket and graphite paper, and the specific steps are as follows:

[0047] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 30 h to obtain an ITO slurry;

[0048] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 210°C and an outlet air temperature of 90°C to obtain ITO powder;

[0049] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 300 kgf / cm 2 , the holding time is 10 minutes, and a green embryo is obtained;

[0050] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 270 MPa and a holding time of 50 min to obtain an ITO blank;

[0051] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and a composite gasket. The composite gasket is placed on the silicon carbide beam. The upper layer of the composite gasket is a zinc oxide gasket, and the lower layer is a graphite paper with a thickness of 0.2 mm. Gradient heating is used for sintering. At 200-700°C, the heating rate is 0.09°C / min, and at 700-1580°C, the heating rate is 0.29°C / min. After reaching the sintering temperature, the temperature is kept high. After sintering, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace is 15°C, the furnace bed is lowered to obtain an ITO rotating target.

[0052] Comparative Example 2: The difference from Example 2 is that the gasket is a zinc oxide gasket, and the specific steps are as follows:

[0053] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 30 h to obtain an ITO slurry;

[0054] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 210°C and an outlet air temperature of 90°C to obtain ITO powder;

[0055] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 300 kgf / cm 2 , the holding time is 10 minutes, and a green embryo is obtained;

[0056] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 270 MPa and a holding time of 50 min to obtain an ITO blank;

[0057] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and a zinc oxide gasket. The zinc oxide gasket is placed on the silicon carbide beam and sintered by gradient heating. The heating rate is 0.09°C / min at 200-700°C and 0.29°C / min at 700-1580°C. After reaching the sintering temperature, the temperature is kept constant. After sintering, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace reaches 15°C, the furnace bed is lowered to obtain the ITO rotating target.

[0058] Comparative Example 3: The difference from Example 2 is that the gasket is an alumina gasket, and the specific steps are as follows:

[0059] (1) Add 97 g of indium oxide powder and 3 g of tin oxide powder to a ball mill containing φ1 mm zirconium beads, then add 100 g of pure water, and then ball mill for 30 h to obtain an ITO slurry;

[0060] (2) drying and granulating the ITO slurry using a centrifugal spray granulator with an inlet air temperature of 210°C and an outlet air temperature of 90°C to obtain ITO powder;

[0061] (3) ITO powder is placed in a mold for molding and pre-pressed at a molding pressure of 300 kgf / cm 2 , the holding time is 10 minutes, and a green embryo is obtained;

[0062] (4) The primary blank is subjected to cold isostatic pressing with a molding pressure of 270 MPa and a holding time of 50 min to obtain an ITO blank;

[0063] (5) The ITO blank is fixed on a base in a high-temperature sintering furnace in a normal pressure oxygen atmosphere for sintering. The base is a silicon carbide beam and an alumina gasket. The alumina gasket is placed on the silicon carbide beam and sintered by gradient heating. At 200-700°C, the heating rate is 0.09°C / min, and at 700-1580°C, the heating rate is 0.29°C / min. After reaching the sintering temperature, the temperature is kept high. After the sintering is completed, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace reaches 15°C, the furnace bed is lowered to obtain the ITO rotating target.

[0064] Performance Testing

[0065] The density and sintering deformation of the target sample were measured, and its appearance was observed to see if there were any cracks. The test results are shown in Table 1:

[0066] Table 1 Performance test results

[0067] Density (%) Deformation (mm / m) Appearance Example 1 99.84 0.51 No cracks Example 2 99.87 0.42 No cracks Example 3 99.90 0.46 No cracks Comparative Example 1 99.86 0.75 No cracks Comparative Example 2 99.85 0.82 No cracks Comparative Example 3 99.80 2.52 No cracks

[0068] Data analysis: It can be seen from the data in the table that the ITO target material obtained by the pad firing method of the present invention has a high density and an extremely low deformation, and no cracks appear on the target material surface.

[0069] It can be seen from Example 2 and Comparative Examples 1-3 that the deformation of the target material obtained by sintering is significantly improved compared with the traditional alumina gasket by using the composite gasket formed by the porous zinc oxide gasket and graphene. This may be because the thermal expansion coefficient between the porous zinc oxide and the blank is quite different, and the pore size of the zinc oxide gasket allows the ITO particles to shrink in a directional manner, and the high-temperature lubrication of the graphite paper prevents adhesion.

[0070] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A pad firing method that significantly reduces the bottom deformation of ITO rotating target sintering, characterized in that: The pad firing method is as follows: the ITO blank is fixed on the base of the sintering furnace for sintering, the base is a silicon carbide beam and a composite gasket, the composite gasket is placed on the silicon carbide beam, and the composite gasket is graphite paper and porous zinc oxide gasket from top to bottom; The pore size of the porous zinc oxide gasket is 50-100 μm.

2. The pad burning method according to claim 1, characterized in that The specific steps of the pad sintering are as follows: the ITO blank is fixed on a base in a high-temperature sintering furnace with a normal pressure oxygen atmosphere for sintering, and the base is a silicon carbide beam and a composite gasket placed on the beam. The sintering is performed in a gradient heating manner, 200-700°C, with a heating rate of 0.08-0.1°C / min, 700-1580°C, with a heating rate of 0.25-0.3°C / min. After reaching the sintering temperature, the temperature is kept constant, and after the sintering is completed, the temperature is lowered at a cooling rate of 0.4°C / min. When the temperature in the furnace is 10-20°C, the hearth is lowered to obtain the ITO rotary target.

3. The pad burning method according to claim 1, characterized in that: The purity of the silicon carbide beam is ≥98%, the temperature resistance is ≥1700°C, and the compressive strength is 500-700Mpa.

4. The pad burning method according to claim 1, characterized in that The purity of the porous zinc oxide gasket is ≥98%.

5. The pad burning method according to claim 1, characterized in that: The thickness of the graphite paper is 0.1-0.2 mm.

6. The pad burning method according to claim 1, characterized in that The preparation steps of the ITO blank are as follows: S1: Add indium oxide powder, tin oxide powder and pure water into a ball mill and ball mill to obtain ITO slurry; S2: spray granulating the ITO slurry to obtain ITO powder; S3: Pre-pressing the ITO powder to obtain a green blank; S4: The primary blank is subjected to cold isostatic pressing to obtain an ITO blank.

7. The pad burning method according to claim 6, characterized in that: The weight ratio of the indium oxide powder to the tin oxide powder in step S1 is 97:

3.

8. The pad burning method according to claim 6, characterized in that: The inlet air temperature of the spray granulation in step S2 is 200-230°C, and the outlet air temperature is 80-100°C.

9. The pad burning method according to claim 6, characterized in that: The molding pressure of the primary pre-pressing molding in step S3 is 200-500Kgf / cm 2 , the holding time is 5-20min.

10. The pad burning method according to claim 6, characterized in that: In the cold isostatic pressing in step S4, the molding pressure is 250-300 MPa and the holding time is 30-60 min.