Preparation method of yttrium oxide ceramic material for semiconductor etching equipment

Abstract

The invention relates to the field of functional ceramics, and provides a preparation method of an yttrium oxide ceramic material for semiconductor etching equipment, which comprises the following steps: (1) adding yttrium oxide powder into a solvent containing a dispersant, carrying out ball milling for a period of time, adding a binder, and continuously carrying out ball milling to obtain slurry; the binder is one or two of polyvinyl butyral and an acrylic acid adhesive, and the weight of the binder is 3-6% of the weight of the yttrium oxide powder; (2) sieving the slurry, and performing spray granulation to obtain granulation powder; and (3) molding the granulation powder to obtain a green body, degreasing the green body, and sintering to obtain the yttrium oxide ceramic material. The yttrium oxide ceramic prepared by the method is high in density and can be stably applied to semiconductor etching equipment, the material preparation process is simple and convenient, and industrial production can be realized.

Description

Technical Field

[0001] The invention relates to the field of functional ceramics, and in particular to a method for preparing yttria ceramic material for semiconductor etching equipment. Background Art

[0002] With the rapid development of integrated circuit technology, plasma etching technology has gradually become an etching technology widely used in nanoscale integrated circuit manufacturing and micro-nano manufacturing processes. As the energy of fluorine-containing ions in the etching gas increases, it will corrode the etcher cavity and the ceramic materials inside the cavity, generating non-volatile fluorides that are deposited on the surface of the wafer, causing the wafer to be contaminated. During the wafer processing process, under high-density plasma conditions, the requirements for the plasma corrosion resistance of the materials in the plasma etching equipment cavity are becoming more and more stringent. The new generation of etching technology requires more powerful and reliable materials to solve problems such as plasma corrosion.

[0003] Yttrium oxide is a very important rare earth oxide belonging to the cubic crystal system. Its melting point and boiling point are as high as 2430℃ and 4300℃ respectively. It has excellent heat resistance and electrical insulation properties, especially excellent plasma corrosion resistance, which is superior to alumina ceramics. It has received widespread attention. For example, patents CN1410353, CN1394811, CN1195647 and CN1375457 all provide a method for manufacturing nano yttrium oxide powder. Yttrium oxide has a very broad application prospect.

[0004] At present, the research on yttrium oxide materials in China mainly focuses on its use as a ceramic additive and its application in laser materials. There is less research on its application in semiconductor equipment structural parts, especially its use in semiconductor etching equipment. Summary of the invention

[0005] The invention provides a method for preparing an yttria ceramic material for semiconductor etching equipment. The prepared yttria ceramic has high density and can be stably used in semiconductor etching equipment. The material preparation process is simple and can be industrially produced.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing yttria ceramic material for semiconductor etching equipment comprises the following steps: (1) adding yttrium oxide powder to a solvent containing a dispersant, and after ball milling for a period of time, adding a binder and continuing ball milling to obtain a slurry; the binder is one or both of polyvinyl butyral and acrylic adhesive, and the weight of the binder is 3-6% of the weight of the yttrium oxide powder; (2) sieving the slurry obtained in step (1) and spray granulating the slurry to obtain granulated powder; (3) The granulated powder obtained in step (2) is molded into a green body, and the green body is degreased and sintered to obtain a yttrium oxide ceramic material.

[0007] Preferably, the solvent is anhydrous ethanol.

[0008] Preferably, the dispersant is a polyoxyethylene derivative or a polyether surfactant.

[0009] Preferably, the weight of the dispersant is 0.05-2% of the weight of the yttrium oxide powder.

[0010] Preferably, the purity of the yttrium oxide powder is 99.9-99.999% and the average particle size is below 0.6 μm.

[0011] Preferably, the ball-to-material ratio of ball milling is (2-3):1, and after ball milling for 40-60 minutes, a binder is added and ball milling is continued for 1-1.5 hours.

[0012] Preferably, the adhesive is a mixture of polyvinyl butyral and acrylic adhesive, and the acrylic adhesive is more preferably an acrylic emulsion adhesive.

[0013] As a further preference, the binder is a mixture of polyvinyl butyral and acrylic adhesive in a dry weight ratio of 1:(2-4).

[0014] Preferably, the weight of the binder is 3-5% of the weight of the yttrium oxide powder.

[0015] Preferably, the solid content of the slurry is 60-65%.

[0016] Preferably, the spray granulation is carried out in a closed granulation tower with an inlet temperature of 120-140°C and an outlet temperature of 60-80°C.

[0017] Preferably, the molding is cold isostatic pressing, and the molding pressure is 100-150Mpa.

[0018] Preferably, the degreasing process is to heat the green body to 500-600° C. at a rate of 0.2-2.5° C. / min in air and keep the temperature for 2-4 hours.

[0019] Preferably, the sintering process is to heat the degreased green body to 1650-1730°C at a rate of 0.5-3°C / min in air, keep the temperature for 4-8h, and then cool naturally to room temperature.

[0020] Therefore, the beneficial effects of the present invention are as follows: using a mixture of two binders, polyvinyl butyral and acrylic adhesive, the particle gradation obtained by spray granulation is more excellent, the sintered body has higher density, and the yttrium oxide ceramic material for semiconductor etching equipment finally obtained also has better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a morphology picture of the granulated powder obtained in Example 5. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below through specific embodiments.

[0023] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the embodiments, unless otherwise specified, are all conventional methods in the art. Unless otherwise specified, parts are all weight parts, temperatures are expressed in ° C or at ambient temperature, and pressures are atmospheric pressure or near atmospheric pressure. There are many variations and combinations of reaction conditions (such as component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges) and conditions that can be used to optimize the purity and yield of the product obtained by the method, and only reasonable routine experiments will be required to optimize such method conditions.

[0024] Example A method for preparing yttria ceramic material for semiconductor etching equipment comprises the following steps: (1) Ball milling slurry The dispersant is added to the solvent anhydrous ethanol and mixed and stirred for 10-20 minutes, and then yttrium oxide powder is added at a ball-to-material ratio of (2-3):1 and ball milling is continued for 40-60 minutes. Then a binder is added and ball milling is performed for 1-1.5 hours to obtain a mixed slurry. The slurry has a solid content of 60-65% and good fluidity.

[0025] The purity of the yttrium oxide powder is 99.9-99.999%. In addition to the purity requirement, the high-purity yttrium oxide ceramic product also needs to be ultra-finely ground and have a uniform particle size distribution, with an average particle size of the powder below 0.6 μm.

[0026] The dispersant is a polyoxyethylene derivative or a polyether surfactant. The amount of the dispersant is 0.05-2% of the weight of the yttrium oxide powder.

[0027] The binder is one or both of polyvinyl butyral and acrylic adhesive, preferably a mixture of polyvinyl butyral and acrylic adhesive in a dry weight ratio of 1:(2-4). The amount of the binder is 3-6% (more preferably 3-5%) of the weight of the yttrium oxide powder. The acrylic adhesive is more preferably an acrylic emulsion adhesive.

[0028] (2) Spray drying After the slurry is screened, it is spray granulated in a granulation tower with a closed spray granulation process. The inlet temperature of the granulation tower is 120-140°C and the outlet temperature is 60-80°C to obtain granulated powder. The granulated powder obtained by spray drying is a solid spherical structure with uniform particle size distribution and good fluidity.

[0029] (3) Molding the granulated powder to obtain a green body, degreasing and sintering the green body to obtain a yttrium oxide ceramic material. The granulated powder is molded into a green body by cold isostatic pressing, and the molding pressure is 100-150Mpa; the green body is heated to 500-600°C in air at a rate of 0.2-2.5°C / min, and kept warm for 2-4h for degreasing; the degreased green body is heated to 1650-1730°C in air at a rate of 0.5-3°C / min, and kept warm for 4-8h for sintering, and naturally cooled to room temperature to obtain a yttrium oxide ceramic material.

[0030] Example 1 A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 500 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry with a solid content of 65% and good fluidity.

[0031] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0032] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0033] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0034] Example 2 A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 12 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 400 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0035] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 130° C. and the outlet temperature is set to 70° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0036] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 130 MPa.

[0037] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.6°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.0°C / min, and the temperature is raised to 1660°C and kept for 6 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0038] Example 3 A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 20 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 600 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0039] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0040] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0041] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 1.2°C / min, and the temperature is raised to 550°C and kept for 4 hours. The heating rate during the sintering process is 1.5°C / min, and the temperature is raised to 1680°C and kept for 6 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0042] Example 4 The difference from Example 1 is that the adhesive uses an acrylic emulsion adhesive with a solid content of 40% to replace the polyvinyl butyral ethanol emulsion with a solid content of 20%. The details are as follows: A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 250 g of acrylic emulsion adhesive emulsion with a solid content of 40%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0043] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0044] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0045] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0046] Example 5 The difference from Example 1 is that the binder is a mixture of a polyvinyl butyral ethanol emulsion with a solid content of 20% and an acrylic emulsion adhesive with a solid content of 40%, and the dry weight ratio of the two is 1:3. The details are as follows: A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 125 g of polyvinyl butyral ethanol emulsion with a solid content of 20% and 187 g of acrylic emulsion adhesive emulsion with a solid content of 40%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0047] (2) The slurry obtained in step (1) is sieved and then fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere, such as Figure 1 As shown, the particle size distribution of the granulated powder is uniform.

[0048] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0049] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0050] Example 6 The difference from Example 1 is that the binder is a mixture of a polyvinyl butyral ethanol emulsion with a solid content of 20% and an acrylic emulsion adhesive with a solid content of 40%, and the dry weight ratio of the two is 1:1. The details are as follows: A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 250 g of polyvinyl butyral ethanol emulsion with a solid content of 20% and 125 g of acrylic emulsion adhesive emulsion with a solid content of 40%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0051] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0052] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0053] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0054] Comparative Example Comparative Example 1 The difference from Example 1 is that the amount of dispersant used in step (1) exceeds the preferred range. A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: In a ball mill, add 4kg of high-purity zirconium balls, 60g of polyether surfactant, and 1.08kg of anhydrous ethanol, and stir for 15 minutes; add 2kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 minutes until the powder is evenly dispersed, and finally add 500g of 20% solid content polyvinyl butyral ethanol emulsion, ball mill for 1 hour, the slurry has high viscosity and poor fluidity. Subsequent operations cannot be performed.

[0055] Comparative Example 2 The difference from Example 1 is that the amount of binder used in step (1) is lower than the preferred range. A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, and continue ball milling for 45 min until the powder is evenly dispersed, and finally add 200 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry.

[0056] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the form of an empty shell.

[0057] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0058] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0059] Comparative Example 3 The difference from Example 1 is that the amount of binder used in step (1) exceeds the preferred range. A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 800 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry.

[0060] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0061] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0062] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 1.2°C / min, and the temperature is raised to 1650°C and kept for 5 hours. The temperature is naturally lowered to room temperature to obtain yttrium oxide ceramic material.

[0063] Comparative Example 4 The difference from Example 1 is that the heating rate of the sintering process in step (4) is higher than the preferred range. The details are as follows: A yttria ceramic material for semiconductor etching equipment is prepared by the following steps: (1) In a ball mill, add 4 kg of high-purity grinding zirconium balls, 10 g of polyether surfactant, and 1.08 kg of anhydrous ethanol, and stir for 15 min; add 2 kg of high-purity yttrium oxide powder to the above solution, continue ball milling for 45 min until the powder is evenly dispersed, and finally add 1000 g of polyvinyl butyral ethanol emulsion with a solid content of 20%, and ball mill for 1 h to obtain a slurry with a solid content of 60-65% and good fluidity.

[0064] (2) The slurry obtained in step (1) is sieved and fed into a spray drying tower at a uniform speed through a silicone hose of a feed pump, and the inlet temperature is set to 140° C. and the outlet temperature is set to 80° C. for spray granulation. The obtained granulated powder is sieved to obtain a granulated powder, which is in the shape of a solid sphere.

[0065] (3) The granulated powder obtained in step (2) is subjected to cold isostatic pressing to obtain a green body, and the molding pressure is 120 MPa.

[0066] (4) The green body obtained in step (3) is placed in a gas furnace for degreasing and sintering. The heating rate during the degreasing process is 0.8°C / min, and the temperature is raised to 600°C and kept for 3 hours. The heating rate during the sintering process is 3.5°C / min, and the temperature is raised to 1650°C and kept for 5 hours. After naturally cooling to room temperature, the material cracks and is unqualified.

[0067] Performance Testing 1. Particle grading of spray granulation Example 1 and Examples 4-6 mainly study the effect of different binders on the particle size distribution of spray granulation. Table 1 lists the particle size distribution of the powder obtained by spray granulation after sieving.

[0068] Table 1. Spray granulation particle size distribution table of Example 1 and Example 4-6 In addition to meeting the basic physical property requirements, the granulated powder also needs to meet the requirements of particle gradation. The green particles processed by the granulated powder with excellent particle gradation are densely packed, have few pores after sintering, and have a high degree of densification of the product. The present invention characterizes the particle gradation by the percentage of the particle size distribution of each embodiment.

[0069] As can be seen from Table 1, Example 1 uses polyvinyl butyral as a single binder, and Example 4 uses acrylic emulsion adhesive as a single binder. The proportion of particles in the 45-200μm range of Example 1 is higher. Because polyvinyl butyral has excellent adhesion and film-forming properties, and strong bonding force, it is more conducive to the formation of large particles under the same granulation process parameters. Acrylic emulsion adhesives have higher plasticity than polyvinyl butyral, but weaker bonding force, so the proportion of large particles is relatively low. Examples 5 and 6 use a mixture of polyvinyl butyral and acrylic emulsion adhesives as a binder, and their particle size distribution is also consistent with the above rules. It can be seen from the above principle description that the amount of polyvinyl butyral and acrylic emulsion adhesives will affect the effect of particle grading. By adjusting the amount and ratio of the two, a granulation powder with excellent particle grading can be obtained.

[0070] 2. Yttrium Oxide Ceramic Material Properties The performance of each embodiment and comparative example was tested by the following test methods: the density of the sample was measured by the Archimedes drainage method; the purity of the product was tested by the GDMS glow discharge mass spectrometry method; the flexural strength was measured by the three-point bending method according to GB / T 6569-1986 on an Instron-5500 universal testing machine. The thermal conductivity was tested by a laser thermal conductivity meter. The results are shown in the following table.

[0071] It can be seen from the above table that the yttria ceramic material prepared in each embodiment of the present invention has good density, high thermal conductivity and good bending strength.

[0072] Compared with Example 1: (1) The amount of binder used in Example 2 is too little, the granulated powder is in the form of an empty shell, and has poor fluidity. The green body processed with the granulated powder has poor density and the sintered density is significantly reduced. Therefore, the amount of binder used needs to be within a reasonable range. Example 3 uses an excessive amount of binder, which increases the difficulty of degreasing and easily leads to an increase in the residual carbon content in the sintered body, affecting the density and electrical properties of the ceramic material. In addition, the amount of binder used is too much, and the cost increases. Taking all factors into consideration, the amount of binder needs to be controlled within a reasonable range. (2) Examples 5 and 6 use a mixture of two binders, polyvinyl butyral and acrylic adhesive. The particle grading obtained by spray granulation is excellent. The green body particles processed with the granulated powder are densely stacked and have high sintering density. The yttrium oxide ceramic material for semiconductor etching equipment finally obtained also has better performance. In addition, since polyvinyl butyral has excellent adhesion and film-forming properties, strong bonding strength, and acrylic emulsion adhesive has higher plasticity, the combination of the two can make the green body have both excellent strength and plasticity, greatly reducing the risk of edge collapse during rough processing, which is conducive to making products with more complex shapes.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing yttria ceramic material for semiconductor etching equipment, characterized in that: The following steps are involved: (1) Adding yttrium oxide powder to a solvent containing a dispersant, adding a binder after ball milling for a period of time and continuing ball milling to obtain a slurry; the binder is one or both of polyvinyl butyral and acrylic adhesive, and the weight of the binder is 3-6% of the weight of the yttrium oxide powder; (2) sieving the slurry obtained in step (1) and spray granulating the slurry to obtain granulated powder; (3) The granulated powder obtained in step (2) is molded into a green body, and the green body is degreased and sintered to obtain a yttrium oxide ceramic material.

2. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1, characterized in that: The dispersant is a polyoxyethylene derivative or a polyether surfactant.

3. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1 or 2, characterized in that: The weight of the dispersant is 0.05-2% of the weight of the yttrium oxide powder.

4. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1, characterized in that: The ball-to-material ratio of ball milling is (2-3):

1. After ball milling for 40-60 min, a binder is added and ball milling is continued for 1-1.5 h.

5. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1, characterized in that: The adhesive is a mixture of polyvinyl butyral and acrylic adhesive.

6. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 5, characterized in that: The adhesive is a mixture of polyvinyl butyral and acrylic adhesive in a dry weight ratio of 1:(2-4).

7. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1, 5 or 6, characterized in that: The weight of the binder is 3-5% of the weight of the yttrium oxide powder.

8. The method for preparing yttria ceramic material for semiconductor etching equipment according to claim 1, characterized in that: The spray granulation is carried out in a closed granulation tower with an inlet temperature of 120-140 ℃ and an outlet temperature of 60-80 ℃.

9. The method for preparing yttria ceramic material for semiconductor etching equipment according to claim 1, characterized in that: The debinding process is to heat the green body to 500-600°C at a rate of 0.2-2.5°C / min in air and keep it warm for 2-4h.

10. The method for preparing a yttria ceramic material for semiconductor etching equipment according to claim 1 or 9, characterized in that: The sintering process is to heat the degreased green body to 1650-1730°C at a rate of 0.5-3°C / min in air, keep it at that temperature for 4-8 hours, and then cool it down naturally to room temperature.

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