Plasma-etching-resistant composite dielectric layer electrostatic chuck and method of making same

Abstract

The application relates to the technical field of semiconductor manufacturing equipment materials, and discloses a composite dielectric layer electrostatic chuck resistant to plasma corrosion and a preparation method thereof. The composite dielectric layer electrostatic chuck is sintered from a composite granulation powder which is made of a specific proportion of yttrium acetate tetrahydrate, basic aluminum acetate, monohydrate citric acid, polyethylene glycol, polyvinyl alcohol and aluminum oxide powder; the yttrium element in the dielectric layer is discontinuously and nanoscale isolated phase distributed at the aluminum oxide grain boundary, so that a continuous yttrium-rich network is avoided, and anisotropic etching is inhibited. The preparation method comprises the following steps: raw material liquid phase coordination complexation and in-situ cross-linking granulation, powder preforming and cold isostatic pressing to obtain a ceramic blank, humidified air is introduced to assist in glue removal and decarburization in the heating and heat preservation stage, then dry air is switched to perform two-step processing of high-temperature densification and then temperature reduction long-time sintering, and finally the finished product is obtained through grinding and polishing. The application can reduce internal residual carbon and optimize the microstructure of the grain boundary.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment materials technology, specifically to a plasma corrosion-resistant composite dielectric layer electrostatic chuck and its preparation method. Background Technology

[0002] Electrostatic chucks are core components used to fix and support silicon wafers in semiconductor wafer manufacturing. During the etching process, they need to be exposed to a plasma environment with strong physical bombardment and chemical activity for a long time. In order to improve the service life of electrostatic chucks, the conventional practice is to dope rare earth elements such as yttrium into the alumina ceramic matrix to improve the overall corrosion resistance of the dielectric layer.

[0003] In actual preparation and application processes, it has been found that, limited by traditional powder mixing and sintering processes, the added yttrium element often becomes locally enriched and interconnected at the grain boundaries of alumina, thus forming a continuous yttrium-rich grain boundary network in the microstructure. Since the bonding strength of the grain boundary region is usually weaker than that inside the grain, when in a strong plasma environment, the etching action will rapidly advance into the depth of the material along these continuous yttrium-rich channels, causing significant anisotropic etching. This uneven loss at the micro level will weaken the bonding force between grains, causing the ceramic grains to peel off from the substrate as a whole. The resulting microparticles will not only contaminate the silicon wafer surface and reduce the yield, but also cause the chuck surface morphology to degrade rapidly, forcing the production line to shut down and replace equipment parts.

[0004] Furthermore, existing electrostatic chucks also face process bottlenecks in the debinding and sintering stages after powder granulation. Organic additives often do not completely decarburize when heated, and some free carbon is trapped in the pores inside the ceramic. This free carbon remaining inside the dielectric layer will damage the insulation properties of the ceramic, causing a significant decrease in volume resistivity, which in turn leads to an increase in leakage current and unstable electrostatic adsorption force during operation. At the same time, in order to pursue high density, the conventional single-stage high-temperature sintering mode usually needs to maintain the highest sintering temperature for a long time. This heat treatment method will cause abnormal growth of alumina matrix grains, which not only aggravates the abnormal aggregation of dopants at grain boundaries, but also makes it difficult to obtain both high density and uniform fine-grained microstructure at the same time. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a plasma-resistant composite dielectric layer electrostatic chuck and its preparation method, which solves the problems of anisotropic etching along continuous yttrium-rich grain boundaries causing particle shedding and internal residual carbon reducing insulation performance under plasma etching of the electrostatic chuck dielectric layer.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides a plasma-resistant composite dielectric layer electrostatic chuck, employing the following technical solution: A plasma-resistant composite dielectric layer electrostatic chuck, wherein the composite dielectric layer of the electrostatic chuck is sintered from composite granulated powder; the yttrium element inside the composite dielectric layer is discretely distributed at the alumina grain boundaries in the form of discontinuous nanoscale isolated phases, thereby avoiding the formation of a continuous yttrium-rich grain boundary network to suppress anisotropic etching; the composite granulated powder is made from raw materials comprising the following parts by weight: 29.9-149.7 parts of yttrium acetate tetrahydrate; 31.8-95.4 parts of basic aluminum acetate; 59.8-433.5 parts of citric acid monohydrate; 10-30 parts of polyethylene glycol; 5-15 parts of polyvinyl alcohol; and 920-980 parts of high-purity alumina powder.

[0007] By adopting the above technical solution, this invention utilizes organic complexation and in-situ polymer crosslinking reaction to control the distribution morphology of yttrium precursor, thereby changing the grain boundary phase structure in the final sintered body. Regarding the specific reaction mechanism, in aqueous phase compatibility, citric acid monohydrate acts as a multidentate ligand, and its carboxyl and hydroxyl groups undergo multiple coordination with yttrium and aluminum ions in the solution. This prevents metal ions from precipitating out midway, thus maintaining the high dispersion of yttrium in the liquid phase. When spray granulation is heated, the remaining uncoordinated carboxyl groups in the citric acid molecules can undergo esterification, dehydration, and polycondensation with the free hydroxyl groups at the ends of polyethylene glycol. This reaction directly builds a polyester crosslinking network on the surface and in the gaps of alumina powder particles. This network fixes the yttrium-containing complex on the polymer skeleton nodes, and due to steric hindrance, yttrium ions have difficulty undergoing long-range migration. Therefore, in the subsequent high-temperature sintering and pyrolysis stage, yttrium will transform in situ into a yttrium-containing crystalline phase. The physical isolation effect generated by this early network means that the yttrium-containing phase can only remain at the junction of alumina grain boundaries, eventually becoming a discontinuous nanoscale isolated phase. Since no connected yttrium-rich grain boundaries are formed, no continuous weak channels can be found during plasma bombardment, and the anisotropic etching rate decreases accordingly, thus improving the corrosion resistance of the dielectric layer.

[0008] Preferably, the composite granulated powder is made from raw materials comprising the following parts by weight: 89.8 parts of yttrium acetate tetrahydrate; 63.6 parts of basic aluminum acetate; 207.4 parts of citric acid monohydrate; 20 parts of polyethylene glycol; 10 parts of polyvinyl alcohol; and 950 parts of high-purity alumina powder.

[0009] By adopting the above technical solution, the number of carboxyl and hydroxyl groups in the system at a specific ratio is just enough to meet the reaction equilibrium required for esterification crosslinking. The resulting three-dimensional mesh size is relatively moderate, which can better fit the gaps between alumina particles, and also makes the distribution of yttrium more uniform overall.

[0010] Preferably, the high-purity alumina powder has an α-phase microstructure, a purity of not less than 99.99%, a median diameter (D50) between 0.1 μm and 0.5 μm, and a specific surface area of ​​5 m². 2 / g to 15m 2 The number average molecular weight of the polyethylene glycol is between 2000 and 4000, with both end groups being free hydroxyl groups. The degree of alcoholysis of the polyvinyl alcohol is 88%, and the average degree of polymerization is 1700.

[0011] By adopting the above technical solutions, the use of α-phase alumina can reduce the phase transformation volume shrinkage that occurs during subsequent sintering; while polyethylene glycol in the corresponding molecular weight range provides a certain degree of flexibility to the chain segments of the crosslinked network; and polyvinyl alcohol with a degree of alcoholysis of 88% increases the steric repulsion force between suspended particles in the system, which helps to maintain the stability of the slurry state.

[0012] Preferably, the composite granulated powder particles contain a polyester crosslinked network formed by in-situ esterification and polycondensation reaction of the residual carboxyl groups of the monohydrated citric acid and the terminal hydroxyl groups of the polyethylene glycol; and the composite dielectric layer has a relative density ≥99.47%, an internal free residual carbon content ≤25ppm, and a volume resistivity ≥3.74×10⁻⁶ at 200℃. 14 Ω·cm.

[0013] By adopting the above technical solution, the in-situ esterification reaction tends to form a solid spherical structure in the granulated powder, which can greatly reduce the hollowing phenomenon of powder that often occurs in spray drying. The density uniformity of the green body is improved accordingly, which also lays the structural foundation for the subsequent firing of a composite dielectric layer with high density, low residual carbon, and high insulation resistance.

[0014] A second aspect of this invention also provides a method for preparing a plasma-resistant composite dielectric layer electrostatic chuck, employing the following technical solution: A method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck includes the following steps: S1. Yttrium acetate tetrahydrate, basic aluminum acetate and citric acid monohydrate are coordinated and complexed in an aqueous phase, followed by the addition of polyethylene glycol, polyvinyl alcohol and high-purity alumina powder to prepare a slurry, and the composite granulated powder is prepared by spray drying and granulation. S2. The composite granulated powder is loaded into a mold for preforming, followed by cold isostatic pressing, and then demolded to obtain a ceramic blank. S3. The ceramic blank is heated, and humidified air is continuously introduced into the furnace during the heat preservation period to carry out debinding and decarburization treatment. S4. After the glue removal is completed, switch to dry air and heat to the first temperature T1 for preliminary densification. Then, cool to the second temperature T2 for long-term sintering. After cooling, grind and polish to obtain the composite dielectric layer of the electrostatic chuck.

[0015] By adopting the above technical solution, the key to this preparation process is to synergistically link the initial in-situ crosslinking granulation with the subsequent wet oxygen debinding and cooling sintering. In the humidification and debinding stage, water vapor molecules penetrate into the pores of the green blank and react with the free carbon remaining from polymer pyrolysis in a high-temperature environment to form a water-gas reaction. This reaction method changes the previous mode of decarburization that relied solely on oxygen diffusion, and instead utilizes gas-solid reaction consumption to quickly convert the carbon deep in the green blank into gas and remove it, thereby minimizing the amount of residual carbon in the closed pores. In the two-step sintering stage, the green body is first provided with the energy to complete the pore closure and preliminary densification at a higher first temperature. Then, the temperature is lowered to a second temperature for long-term sintering. At this time, the migration of grain boundaries slows down due to the lower temperature, and the alumina matrix grains usually do not grow excessively. At the same time, the diffusion distance of yttrium atoms is limited, so that the yttrium phase can only stay at the relatively dispersed grain boundary intersections. Through process adjustment, the micro-distribution of the material is controlled.

[0016] Preferably, step S1 is implemented as follows: yttrium acetate tetrahydrate and basic aluminum acetate are dissolved in deionized water to obtain a mixed metal salt solution; citric acid monohydrate is added to dissolve the solution, and ammonia is added dropwise to adjust the pH of the system to 4.5-5.5. The solution is stirred continuously at room temperature for 1-2 hours to form a complex solution; polyethylene glycol and polyvinyl alcohol are added to the complex solution, and the solution is heated to 60°C and stirred to dissolve; then the high-purity alumina powder is added, and the solution is transferred to a zirconia ball mill to add deionized water to adjust the solid content to 50wt%-60wt%. The solution is ball-milled for 12-24 hours to prepare a homogeneous ceramic slurry.

[0017] By adopting the above technical solution, controlling the pH value within a limited range allows the degree of dissociation of citric acid to be just right for coordination with metal ions; if the acidity is too strong, the coordination complexation is often incomplete, while if the alkalinity is too high, the metal ions will directly form hydroxide precipitates.

[0018] Preferably, in step S1, the process of feeding the ball-milled ceramic slurry into a centrifugal spray drying tower for atomization granulation is set with the following process parameters: inlet air temperature of 150℃-180℃, outlet air temperature of 90℃-110℃, and atomization disc rotation speed controlled at 8000-12000 r / min; and composite granulated powder with a particle size distribution between 30μm and 80μm is collected.

[0019] By adopting the above technical solution, the set inlet and outlet air temperatures can ensure that the moisture on the surface of the droplets evaporates in time, and also provide the necessary heat for the internal esterification and polycondensation reaction; at the same time, this temperature range generally will not cause the polymer to be overheated and degrade.

[0020] Preferably, the specific process parameters for step S2 are as follows: the composite granulated powder is subjected to bidirectional dry pressing preforming under a pressure of 10-30 MPa; after vacuum sealing the preformed blank, it is held under pressure for 10-20 minutes in a cold isostatic press with a pressure of 200-250 MPa.

[0021] By adopting the above technical solution, and using a combination of bidirectional dry pressing and high-pressure cold isostatic pressing to compact the pores between granulated powders, the resulting green body exhibits a more uniform bulk density, which can reduce the internal stress generated during later sintering shrinkage.

[0022] Preferably, in step S3, the specific process parameters for wet oxygen-assisted debinding are as follows: heating to 400℃-600℃ at a heating rate of 1-2℃ / min, and maintaining the temperature for 2-4 hours; during the heat preservation period, the relative humidity of the humidified air is controlled at 60%-80%.

[0023] By adopting the above technical solution, using a slightly lower heating rate and appropriate humidity air, the rate at which organic matter is discharged and the rate at which gas diffuses outward can be roughly balanced, and the green blank will not be forced into microcracks due to the pressure generated by the internal accumulation of gas.

[0024] Preferably, in step S4, the specific process parameters for the two-step reaction sintering are as follows: the temperature is increased to a first temperature T1 at a heating rate of 3-5℃ / min, where the first temperature T1 is 1380℃-1420℃, and held at this temperature for 1-2 hours; then the temperature is rapidly decreased to a second temperature T2 at a cooling rate of 10℃ / min, where the second temperature T2 is 1280℃-1320℃, and held at this temperature for 10-15 hours for long-term sintering.

[0025] By adopting the above technical solution, the first temperature stage mainly provides the initial driving force for grain nucleation and densification; in the second temperature stage, the diffusion activity at the interface is weakened, which can suppress grain boundary slip and grain coarsening to a certain extent, which is conducive to firing out fine grain structure with discrete internal phase distribution.

[0026] This invention provides a plasma-resistant composite dielectric layer electrostatic chuck and its preparation method. It has the following beneficial effects: 1. This invention spatially anchors the metal complex through an in-situ esterification crosslinking network of citric acid monohydrate and polyethylene glycol, causing yttrium in the final sintered body to be discretely distributed at the alumina grain boundaries in the form of discontinuous nanoscale isolated phases. This discontinuous grain boundary structure blocks the channel for plasma to perform deep etching along the yttrium-rich phase, suppresses the particle shedding phenomenon caused by anisotropic etching, and improves the corrosion resistance and service life of the electrostatic chuck composite dielectric layer in etching equipment.

[0027] 2. The preparation process of this invention introduces humidified air to assist in debinding during the heating stage of the green blank. The gas generated by the reaction of water vapor and free residual carbon at high temperature is discharged, transforming the conventional oxygen diffusion decarburization into gas-solid reaction decarburization. This treatment method can penetrate deep into the internal pores of the green blank to accelerate the removal of carbon elements, avoid carbon residue in the closed pores, reduce the amount of free residual carbon inside the finished dielectric layer, and thus ensure the stable volume resistivity and insulation reliability required by the chuck in the high temperature environment.

[0028] 3. This invention employs a two-step sintering process, first heating to a first temperature and then cooling to a second temperature. In the first temperature stage, a high thermodynamic driving force is used to complete the pore closing and densification, followed by long-term sintering at a lower second temperature. The cooling process restricts the rapid migration of grain boundaries and the long-range diffusion of atoms, ensuring that the ceramic achieves a high relative density while suppressing the abnormal growth of matrix grains and the aggregation of yttrium phase, ultimately obtaining a composite dielectric layer with a dense microstructure and uniform phase distribution. Attached Figure Description

[0029] Figure 1 Full-band Fourier transform infrared spectrum for verifying the in-situ crosslinking process of this invention; Figure 2 Local wavenumber band Fourier transform infrared spectrum for verifying the in-situ crosslinking process of this invention; Figure 3 Thermogravimetric analysis comparison chart for verifying the steam-assisted decarbonization mechanism of this invention; Figure 4 Comparison of mass spectrometry carbon dioxide escape signals for verifying the steam-assisted decarbonization mechanism of the present invention; Figure 5 A comparison chart of dynamic linear shrinkage rates for verifying the two-step reaction sintering activation mechanism of the present invention; Figure 6 This is a biaxial trend graph showing the relative density and free residual carbon content of each group of samples prepared in this invention. Figure 7 This is a comparison chart of the increase in roughness and the density of surface detached particles after etching for each group of samples prepared in this invention. Figure 8 The graph shows the evolution trend of volume resistivity of each group of samples in this invention at a high temperature of 200℃. Figure 9 This is a comparative distribution diagram of dielectric breakdown strength of various groups of samples in this invention at a high temperature of 200℃. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] See attached document Figure 1 -Appendix Figure 9 : The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0032] Alumina, CAS number 1344-28-1, has an α-phase microstructure, a purity of not less than 99.99%, a median diameter (D50) of 0.1 μm to 0.5 μm, and a specific surface area of ​​5 m² / g to 15 m² / g.

[0033] Yttrium acetate tetrahydrate, CAS number 23363-14-6, is a commercially available analytical grade and is used as a yttrium source precursor.

[0034] Basic aluminum acetate, CAS number 142-03-0, is a commercially available analytical grade product used as a highly active aluminum source precursor.

[0035] Citric acid monohydrate, CAS number 5949-29-1, is commercially available analytical grade.

[0036] Polyethylene glycol, CAS number 25322-68-3, has a main chain repeating unit composed of a long-chain polyether structure formed by the ring-opening homopolymerization of ethylene oxide. Both end groups are free hydroxyl groups, the number average molecular weight ranges from 2000 to 4000, and the molecular weight distribution index is not greater than 1.2.

[0037] Polyvinyl alcohol, CAS number 9002-89-5, has a degree of alcoholysis of 88% and an average degree of polymerization of 1700.

[0038] Preparation Example 1: This preparation example provides a method for preparing composite granulated powder A under preferred parameters, including the following steps: Weigh 89.8 parts by weight of yttrium acetate tetrahydrate and 63.6 parts by weight of basic aluminum acetate, add them to a mixing tank, add deionized water and stir until completely dissolved to obtain a mixed metal salt solution; Add 207.4 parts by weight of citric acid monohydrate to the above mixed metal salt solution and stir until completely dissolved; slowly add 25% ammonia water to adjust the pH of the system to 5.0, and continue stirring at room temperature for 1.5 hours to allow the metal ions and citric acid to fully undergo a coordination reaction to form a homogeneous complex solution. Add 20 parts by weight of polyethylene glycol with a number average molecular weight of 3000 and 10 parts by weight of polyvinyl alcohol to the complexing solution, heat to 60°C and stir until completely dissolved; then add 950 parts by weight of high-purity alumina powder with a median diameter of 0.3 μm to the mixture. The above mixture was transferred to a zirconia ball mill, and the mass ratio of material, balls and water was controlled at 1:2:0.8. An appropriate amount of deionized water was added to adjust the system to a solid content of 55wt%. The mixture was ball-milled for 18 hours to prepare a homogeneous ceramic slurry. The ball-milled ceramic slurry was pumped into a centrifugal spray drying tower for atomization granulation via a diaphragm pump. The inlet air temperature was set to 165℃, the outlet air temperature to 100℃, and the rotation speed of the atomizing disc was controlled at 10000 r / min. During the droplet heating and drying stage, the residual carboxyl groups of citric acid and the terminal hydroxyl groups of polyethylene glycol underwent an in-situ esterification and polycondensation reaction, and composite granulated powder A with a particle size distribution between 30μm and 80μm was collected.

[0039] Preparation Example 2: This preparation example provides a method for preparing composite granulated powder B with lower parameter limits, including the following steps: Weigh 29.9 parts by weight of yttrium acetate tetrahydrate and 31.8 parts by weight of basic aluminum acetate, add them to a mixing tank, add deionized water and stir until completely dissolved to obtain a mixed metal salt solution; Add 59.8 parts by weight of citric acid monohydrate to the above mixed metal salt solution and stir until completely dissolved; slowly add 25% ammonia water to adjust the pH of the system to 4.5, and continue stirring at room temperature for 1 hour to allow the metal ions and citric acid to fully undergo a coordination reaction to form a homogeneous complex solution. Add 10 parts by weight of polyethylene glycol with a number average molecular weight of 2000 and 5 parts by weight of polyvinyl alcohol to the complexing solution, heat to 60°C and stir until completely dissolved; then add 980 parts by weight of high-purity alumina powder with a median diameter of 0.1 μm to the mixture. The above mixture was transferred to a zirconia ball mill, and the mass ratio of material, balls and water was controlled at 1:2:0.8. An appropriate amount of deionized water was added to adjust the system to a solid content of 50wt%. The mixture was ball-milled for 12 hours to prepare a homogeneous ceramic slurry. The ball-milled ceramic slurry was pumped into a centrifugal spray drying tower for atomization granulation via a diaphragm pump; the inlet air temperature was set to 150℃, the outlet air temperature to 90℃, and the rotation speed of the atomizing disc was controlled at 8000 r / min; composite granulated powder B was collected.

[0040] Preparation Example 3: This preparation example provides a method for preparing composite granulated powder C with upper limit parameters, including the following steps: Weigh 149.7 parts by weight of yttrium acetate tetrahydrate and 95.4 parts by weight of basic aluminum acetate, add them to a mixing tank, add deionized water and stir until completely dissolved to obtain a mixed metal salt solution; Add 433.5 parts by weight of citric acid monohydrate to the above mixed metal salt solution and stir until completely dissolved; slowly add 28% ammonia water to adjust the pH of the system to 5.5, and continue stirring at room temperature for 2 hours to allow the metal ions and citric acid to fully undergo a coordination reaction to form a homogeneous complex solution. Add 30 parts by weight of polyethylene glycol with a number average molecular weight of 4000 and 15 parts by weight of polyvinyl alcohol to the complexing solution, heat to 60°C and stir until completely dissolved; then add 920 parts by weight of high-purity alumina powder with a median diameter of 0.5 μm to the mixture. The above mixture was transferred to a zirconia ball mill, and the mass ratio of material, balls and water was controlled at 1:2:0.8. An appropriate amount of deionized water was added to adjust the system to a solid content of 60wt%. The mixture was ball-milled for 24 hours to prepare a homogeneous ceramic slurry. The ball-milled ceramic slurry was pumped into a centrifugal spray drying tower for atomization granulation via a diaphragm pump; the inlet air temperature was set to 180℃, the outlet air temperature to 110℃, and the rotation speed of the atomizing disc was controlled at 12000r / min; composite granulated powder C was collected.

[0041] Example 1: This embodiment provides a method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck, including the following steps: The composite granulated powder A obtained in Preparation Example 1 was loaded into a metal mold and preformed by bidirectional dry pressing under a pressure of 20 MPa. The preformed green body was vacuum sealed, placed in a cold isostatic press, and held under a pressure of 220 MPa for 15 minutes. After demolding, a ceramic green body was obtained. The ceramic blank was placed in an atmospheric pressure degreasing and sintering integrated furnace and heated to 500°C at a heating rate of 1.5°C / min. It was kept at a constant temperature for 3 hours. During the holding period, humidified air with a relative humidity of 70% was continuously introduced into the furnace to remove the glue. After the holding period was completed, the humidified air was stopped. Dry air is introduced into the furnace and the temperature is raised to 1400℃ at a rate of 4℃ / min, and held at this temperature for 1.5 hours. Then, the temperature is rapidly reduced to 1300℃ at a rate of 10℃ / min, and sintered at this temperature for 12 hours. After sintering, the sintered green body is obtained by naturally cooling to room temperature in the furnace. The sintered blank is subjected to surface grinding and polishing to obtain the composite dielectric layer of the electrostatic chuck.

[0042] Example 2: This embodiment provides a method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck, including the following steps: The composite granulated powder A obtained in Preparation Example 1 was loaded into a metal mold and preformed by bidirectional dry pressing under a pressure of 10 MPa. The preformed green body was vacuum sealed, placed in a cold isostatic press, and held under a pressure of 200 MPa for 10 minutes. After demolding, a ceramic green body was obtained. The ceramic blank was placed in an atmospheric pressure degreasing and sintering integrated furnace and heated to 400°C at a heating rate of 1°C / min. It was kept at a constant temperature for 2 hours. During the holding period, humidified air with a relative humidity of 60% was continuously introduced into the furnace to remove the glue. After the holding period was completed, the humidified air was stopped. Dry air is introduced into the furnace and the temperature is raised to 1380°C at a rate of 3°C / min, and held at this temperature for 1 hour. Then, the temperature is rapidly lowered to 1280°C at a rate of 10°C / min, and sintered at this temperature for 10 hours. After sintering, the sintered green body is obtained by naturally cooling to room temperature in the furnace. The sintered blank is subjected to surface grinding and polishing to obtain the composite dielectric layer of the electrostatic chuck.

[0043] Example 3: This embodiment provides a method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck, including the following steps: The composite granulated powder A obtained in Preparation Example 1 was loaded into a metal mold and preformed by bidirectional dry pressing under a pressure of 30 MPa. The preformed green body was vacuum sealed, placed in a cold isostatic press, and held under a pressure of 250 MPa for 20 minutes. After demolding, a ceramic green body was obtained. The ceramic blank was placed in an atmospheric pressure degreasing and sintering integrated furnace and heated to 600°C at a heating rate of 2°C / min. It was kept at a constant temperature for 4 hours. During the holding period, humidified air with a relative humidity of 80% was continuously introduced into the furnace to remove the glue. After the holding period was completed, the humidified air was stopped. Dry air was introduced into the furnace and the temperature was raised to 1420°C at a rate of 5°C / min and held at that temperature for 2 hours. Then the temperature was rapidly lowered to 1320°C at a rate of 10°C / min and sintered at this temperature for 15 hours. After sintering, the sintered green body was naturally cooled to room temperature in the furnace. The sintered blank is subjected to surface grinding and polishing to obtain the composite dielectric layer of the electrostatic chuck.

[0044] Example 4: This embodiment provides a method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck, including the following steps: The composite granulated powder B obtained in Preparation Example 2 was loaded into a metal mold and preformed by bidirectional dry pressing under a pressure of 20 MPa. The preformed green body was vacuum sealed, placed in a cold isostatic press, and held under a pressure of 220 MPa for 15 minutes. After demolding, a ceramic green body was obtained. The ceramic blank was placed in an atmospheric pressure degreasing and sintering integrated furnace and heated to 500°C at a heating rate of 1.5°C / min. It was kept at a constant temperature for 3 hours. During the holding period, humidified air with a relative humidity of 70% was continuously introduced into the furnace to remove the glue. After the holding period was completed, the humidified air was stopped. Dry air is introduced into the furnace and the temperature is raised to 1400℃ at a rate of 4℃ / min, and held at this temperature for 1.5 hours. Then, the temperature is rapidly reduced to 1300℃ at a rate of 10℃ / min, and sintered at this temperature for 12 hours. After sintering, the sintered green body is obtained by naturally cooling to room temperature in the furnace. The sintered blank is subjected to surface grinding and polishing to obtain the composite dielectric layer of the electrostatic chuck.

[0045] Example 5: This embodiment provides a method for preparing a plasma corrosion-resistant composite dielectric layer electrostatic chuck, including the following steps: The composite granulated powder C obtained in Preparation Example 3 was loaded into a metal mold and preformed by bidirectional dry pressing under a pressure of 20 MPa. The preformed green body was vacuum sealed, placed in a cold isostatic press, and held under a pressure of 220 MPa for 15 minutes. After demolding, a ceramic green body was obtained. The ceramic blank was placed in an atmospheric pressure degreasing and sintering integrated furnace and heated to 500°C at a heating rate of 1.5°C / min. It was kept at a constant temperature for 3 hours. During the holding period, humidified air with a relative humidity of 70% was continuously introduced into the furnace to remove the glue. After the holding period was completed, the humidified air was stopped. Dry air is introduced into the furnace and the temperature is raised to 1400℃ at a rate of 4℃ / min, and held at this temperature for 1.5 hours. Then, the temperature is rapidly reduced to 1300℃ at a rate of 10℃ / min, and sintered at this temperature for 12 hours. After sintering, the sintered green body is obtained by naturally cooling to room temperature in the furnace. The sintered blank is subjected to surface grinding and polishing to obtain the composite dielectric layer of the electrostatic chuck.

[0046] Comparative Example 1: Compared with Example 1, the differences are as follows: the green body is prepared by a traditional solid-phase powder mechanical mixing process and a traditional high-temperature single-step sintering is adopted; that is, high-purity alumina powder is directly mixed with an equivalent mass of yttrium oxide powder, and polyvinyl alcohol is added as a binder for conventional spray granulation and molding; conventional dry air is introduced throughout the debinding stage without humidifying air; the two-step sintering method is not used in the sintering stage, but the temperature is directly raised to 1600℃ and held at a constant temperature for 4 hours; the rest are the same.

[0047] Comparative Example 2: Compared with Example 1, the difference is that: in the liquid phase batching stage of powder preparation, citric acid monohydrate and polyethylene glycol are not added; that is, only yttrium acetate tetrahydrate and basic aluminum acetate aqueous solution are mixed with alumina powder to form a slurry, and no liquid phase complex and in-situ polyester crosslinking network are constructed; all other aspects are the same.

[0048] Comparative Example 3: Compared with Example 1, the difference is that: in the liquid phase feeding stage of powder preparation, basic aluminum acetate is not added; that is, the metal salt solution contains only yttrium acetate tetrahydrate and no homologous highly active aluminum source precursor is introduced; all other aspects are the same.

[0049] Comparative Example 4: Compared with Example 1, the difference is that: during the degreasing and debinding stage, humidified air is not introduced; that is, during the degreasing and debinding process at 500℃, conventional dry air is introduced throughout, and the water vapor-assisted hydrolysis chain breaking and wet oxygen catalytic decarbonization process are missing; all other aspects are the same.

[0050] Comparative Example 5: Compared with Example 1, the difference is that the two-step sintering process is not used in the sintering stage; that is, after the glue is removed, the temperature gradients T1 and T2 are not set, but the temperature is directly raised to 1550°C at the conventional heating rate and kept at a constant temperature for 6 hours, and then naturally cooled with the furnace; the rest are the same.

[0051] Test Example 1: This test example provides experimental verification of the feasibility of the liquid-phase in-situ crosslinking mechanism of the present invention. The experimental subjects include two sets of comparative samples: the first set is a small amount of liquid-phase ceramic slurry extracted after the preparation step in Example 1, which is placed in a vacuum freeze-drying environment at -50°C for 48 hours to obtain freeze-dried comparative powder that has not undergone a high-temperature drying process; the second set is composite granulated powder A collected by conventional spray drying in the preparation step in Example 1.

[0052] The specific Fourier transform infrared spectroscopy test steps are as follows: Weigh approximately 2.5 mg each of the freeze-dried control powder and the composite granulated powder A, and place them in an agate mortar along with 250 mg of fully dried spectral-grade potassium bromide powder for uniform grinding in the same direction.

[0053] The ground and mixed powder is evenly spread into the mold cavity and pressed into a tablet press at a constant pressure of 10 MPa for about 1 minute to prepare a test sheet with uniform thickness and a semi-transparent appearance.

[0054] Two sets of test slices were placed sequentially in the sample chamber of the Fourier transform infrared spectrometer. Before the test, the spectrum was collected using the ambient air in the laboratory as a background reference for baseline subtraction.

[0055] The instrument's scanning wavenumber range was set between 4000 cm⁻¹ and 400 cm⁻¹, and the spectral resolution was set to 4 cm⁻¹. Each thin-slice sample was continuously scanned 32 times to suppress random background noise of the instrument. The original spectral characteristic data of the absorbance of each sample as a function of wavenumber were recorded and exported.

[0056] Table 1: Characteristic peak positions and absorbance test data of major functional groups of powder before and after reaction According to Table 1 and Figure 1 and Figure 2 The freeze-dried control powder was at 3421.4 cm⁻¹. -1 and 1708.2cm -1 The sample exhibits strong absorption at 1738.4 cm⁻¹, indicating the presence of free polyethylene glycol terminal hydroxyl groups and incompletely complexed citric acid residual carboxyl groups in the system; while the absorbance of the aforementioned characteristic peak of composite granulated powder A decreases significantly, and the absorbance at 1738.4 cm⁻¹ is also significantly reduced. -1 With 1192.1cm -1The characteristic peaks broadened significantly and their intensity increased; this change confirms that esterification, dehydration, and polycondensation reactions occurred during spray drying, indicating that citric acid and polyethylene glycol formed a polyester network through covalent crosslinking. In liquid-phase preparation, water evaporation leads to solute migration and aggregation, while the in-situ polyester crosslinking network formed by this invention can provide strong structural resistance within the granulated powder, overcoming the capillary contraction force generated by water vaporization and limiting the free diffusion of metal complexes. This ensures the high dispersion of the metal precursor at the microscale, prevents component segregation, and provides a fundamental guarantee for eliminating continuous grain boundary secondary phases and obtaining a uniform microstructure during subsequent sintering.

[0057] Test Example 2: This test example provides experimental verification of the steam-assisted hydrolysis and wet oxygen decarburization mechanism of the present invention. The experimental object is the green body fragments obtained by bidirectional dry pressing and crushing of the composite granulated powder A obtained in Preparation Example 1 under 20 MPa pressure, thereby simulating the dense packing state of real ceramic green bodies.

[0058] The specific thermogravimetric-mass spectrometry (TGA-MS) test procedures are as follows: Approximately 30 mg of raw blank fragments were selected and placed in a high-purity alumina micro crucible. The crucible was then placed inside the heating chamber of a thermogravimetric analyzer and connected to a quadrupole mass spectrometer for real-time online gas monitoring.

[0059] Two different carrier gas environments were set up for comparative testing. The control group was introduced with high-purity dry air at a flow rate of 50 mL / min; the experimental group was introduced with humidified air at the same flow rate, which was obtained by bubbling and mixing high-purity dry air through a deionized water bath generator at a constant temperature of 60℃, and the relative humidity of the system was controlled at about 70%.

[0060] Start the heating program and control the furnace to heat from room temperature (approximately 25°C) to 800°C at a uniform heating rate of 5°C / min.

[0061] During the heating process, the thermogravimetric analyzer records the change in sample mass with temperature in real time. The mass spectrometer, which operates simultaneously, sets the ionization energy to 70 eV and focuses on monitoring the characteristic ion current signal with a mass-to-charge ratio (m / z) of 44 to track the escape behavior of carbonaceous species inside the sample as carbon dioxide gas. After the test, the temperature, mass loss, and ion current intensity data of the entire process are exported.

[0062] Table 2: Characteristic data of green blanks obtained by thermogravimetric-mass spectrometry under dry and humidified air conditions According to Table 2 and Figure 3 and Figure 4The maximum weight loss rate of the green sample under humidified air environment corresponds to a temperature that drops to 389.7℃, nearly 100℃ earlier than in the dry environment. In ceramic preparation, organic matter undergoes carbon chain condensation upon heating to form residual carbon, affecting insulation performance. High-temperature water vapor exhibits nucleophilic activity above 300℃, promoting the hydrolysis and breakage of macromolecular ester groups and ether bonds, degrading the polymer into volatile short-chain monomers. Mass spectrometry data shows that the peak value of carbon dioxide ion current at m / z=44 is significantly increased under humidified conditions, and the total mass loss rate increases to 12.87%. This indicates that the humid oxygen environment reduces the activation energy of the amorphous carbon oxidation reaction, accelerating the conversion of residual carbon in the pores into carbon dioxide at around 400℃. This humid oxygen low-temperature decarburization mechanism not only improves the glue removal efficiency, avoids microcracks in the green sample caused by high-temperature gas expansion and cuts off potential leakage channels, but also provides a clean reaction interface for the conversion of yttrium and aluminum precursors into highly active amorphous oxide shells.

[0063] Test Example 3: This test example provides experimental verification of the two-step reaction sintering activation mechanism of the present invention. The experimental subjects include two sets of samples: the ceramic green body obtained after humidification and debinding treatment in Example 1, and the ceramic green body obtained after conventional drying and debinding treatment in Comparative Example 1, to compare the direct influence of the presence or absence of a highly active amorphous shell on the sintering densification behavior.

[0064] The specific steps for testing the dynamic sintering shrinkage rate using a thermal expansion apparatus are as follows: The unfinished blanks of Example 1 and Comparative Example 1 were processed into standard cylindrical specimens with a diameter of 6 mm and a length of 15 mm, respectively. The two end faces of the specimens were carefully polished to ensure geometric parallelism and surface flatness.

[0065] Place the sample horizontally in the alumina sample holder of the high-temperature thermal expansion instrument, adjust the position of the instrument push rod so that the contact probe is completely in contact with one end face of the sample, and apply a constant initial contact force of 0.2N to ensure that the probe does not slip or detach during the entire thermal shrinkage cycle.

[0066] The test furnace was sealed and evacuated to a slight negative pressure. Then, high-purity air at a flow rate of 40 mL / min was introduced as the test atmosphere. The heating program was set to heat from room temperature to 1500℃ at a uniform rate of 3℃ / min.

[0067] The instrument's internal high-precision differential transformer records the axial displacement change of the sample in real time during the heating process. The testing system automatically deducts the back-bottom error caused by the thermal expansion of the alumina push rod and support, and records and exports the relative linear shrinkage rate data of the sample at different temperature nodes.

[0068] Table 3: Comparison of characteristic parameters of thermal expansion test of raw blanks from Example 1 and Comparative Example 1 According to Table 3 and Figure 5The significant shrinkage initiation temperature of the preform in Example 1 was 1083.6℃, ​​nearly 170℃ earlier than that of Comparative Example 1. Traditional solid-phase mixed powders require higher thermal energy to overcome the mass migration energy barrier, resulting in a higher densification temperature. However, after the initial pyrolysis, the liquid-phase system of Example 1 generates amorphous Al-O and YO-OH shells on the surface of the main particles. This transition phase has high surface energy, reduces diffusion activation energy, and promotes mass transport and atomic rearrangement at lower temperatures. At 1400℃, the linear shrinkage rate of Example 1 reached 16.85%, compared to the linear shrinkage rate at 1500℃. The shrinkage rate (17.12%) is close to that of the main shrinkage stage of densification, indicating that the main shrinkage stage has been basically completed. At the same temperature, the shrinkage rate of the comparative example 1 is only 11.23%. The forward shift of this densification temperature zone provides a basis for two-step reaction sintering. Preliminary densification is achieved in the T1 stage of 1380℃-1420℃ to avoid excessive growth of yttrium-rich secondary phases at high temperatures. Long-term heat preservation is carried out in the T2 stage of 1280℃-1320℃ to suppress grain coarsening by reducing grain boundary mobility and promote the discrete distribution of secondary phases by combining vacancy diffusion, thereby improving the macroscopic etching resistance uniformity of the material.

[0069] Test Example 4: This test example provides experimental verification of the feasibility of controlling the macroscopic physical properties and residual carbon content of the present invention. The experimental subjects are the final sintered entities of the composite dielectric layers prepared in Examples 1 to 5, and Comparative Examples 3 to 5, mainly comparing the direct impact of differences in process conditions on the ceramic density and the effect of eliminating internal impurities.

[0070] The specific physical indicators and carbon content testing procedures are as follows: From the interior of each composite dielectric layer, block samples of approximately 10mm×10mm×3mm in size were cut using a diamond water-cooled cutting machine for density testing. At the same time, the scraps generated during the cutting process were collected and ground into fine powder using a tungsten carbide mortar for subsequent residual carbon content analysis.

[0071] The actual bulk density of the sample was determined using Archimedes' displacement method. The sample was weighed dry in air, then placed in deionized water and boiled for 2 hours to allow water to completely penetrate the open pores of the sample. After cooling to room temperature, the sample was suspended in deionized water and its water mass was measured. The sample was then removed, the surface moisture was wiped off, and its saturated mass was measured. The actual bulk density was calculated using Archimedes' formula, and the relative density was obtained by converting this density to the theoretical density of the phase.

[0072] Approximately 0.5 g of ground ceramic powder sample was weighed, and tungsten-tin flux was added before placing it into the ceramic combustion crucible of a high-frequency infrared carbon-sulfur analyzer. The sample was heated to over 2000℃ in a high-frequency induction heating furnace purged with high-purity oxygen, causing it to completely melt and burn. The remaining carbon in the sample was completely oxidized, releasing carbon dioxide gas. The intensity of the gas absorption peak was measured using the infrared absorption detection cell inside the instrument, and the absolute mass fraction of free carbon inside the sample was calculated using a standard curve.

[0073] Table 4: Macroscopic index test data of composite dielectric layer samples from the examples and comparative examples According to Table 4 and Figure 6 The dielectric layers prepared in Examples 1 to 5 all had a relative density of over 99.4% and a free residual carbon content of less than 30 ppm. High density and low residual carbon are key indicators for ensuring the insulation life of plasma corrosion resistant components. In Comparative Example 3, due to the lack of a highly active aluminum source, a complete low activation energy reaction shell could not be formed, resulting in difficulty in removing pores and a relative density of 96.03%, confirming the necessity of the yttrium aluminum co-complex precursor for promoting densification. In Comparative Example 4, the lack of water vapor assistance during binder removal made it difficult to remove deep residual carbon, with a free carbon content of 187 ppm, indicating that low-temperature hydrolysis in a humid oxygen environment helps reduce the accumulation of carbon impurities. Comparative Example 5 used a single-step high-temperature sintering process, resulting in a relative density of 98.39% and an increase in residual carbon to 43 ppm. This was because the high-temperature single-step sintering caused premature sealing of the surface layer, encapsulating pores and residual carbon within the grains. The two-step reaction sintering process of this invention, combined with the binder removal mechanism, avoids the encapsulation of pores and residual carbon, ensuring the density and high purity of the internal structure.

[0074] Test Example 5: This test example provides experimental verification of the plasma corrosion resistance and surface dust suppression mechanism of the composite dielectric layer of the present invention. The experimental subjects are ceramic sintered body samples prepared in Examples 1 to 5, and Comparative Examples 1, 2 and 5, aiming to examine the resistance of microstructures prepared by different processes to selective etching under harsh halogen plasma environment.

[0075] The specific steps for plasma corrosion resistance testing are as follows: Each group of ceramic samples was uniformly processed into circular pieces with a diameter of 50 mm and a thickness of 2 mm. One side of the surface was precision ground and chemically mechanically polished to make the initial surface roughness uniformly controlled between 5 nm and 8 nm. The samples were then purged with high-purity nitrogen in a clean room environment and the initial precise mass of the samples was recorded.

[0076] The polished sample was placed on the tray of an inductively coupled plasma etching (ICP-C) apparatus to simulate the dielectric etching process environment in semiconductor wafer manufacturing. A mixed reactive gas of CF4, O2, and Ar was introduced into the vacuum chamber. The RF source power was set to 1500W, the bias power to 500W, and the chamber pressure was maintained at 15mTorr. Accelerated etching bombardment was carried out continuously for 40 hours.

[0077] After the etching process is completed, the sample is removed and its final mass is weighed using a microbalance. The absolute mass loss rate is calculated by dividing the mass difference by the exposed area. Five 50μm×50μm scanning areas are randomly selected in the center and edge regions of the sample using an atomic force microscope to measure the surface roughness after etching. The average value is used to calculate the increase in roughness. Finally, the microstructure of the sample surface is scanned using a wafer surface particle detector to count the number of detached particles with a diameter greater than 0.1μm per unit area.

[0078] Table 5: Test data on corrosion resistance and dust generation performance of each group of samples after plasma etching According to Table 5 and Figure 7 After plasma etching, the increase in surface roughness in Examples 1 to 5 was controlled within 20 nm, and the density of detached particles was less than 12 ea / cm. 2 During etching, yttrium reacts with fluorine groups to generate non-volatile byproducts that form a local barrier layer, while the alumina matrix is ​​consumed. Comparative Example 1 uses solid-phase mixing, forming a continuous yttrium-rich phase at the grain boundaries, which exacerbates anisotropic etching, leading to a sharp increase in roughness and severe particle contamination. Comparative Example 2 also suffers from poor etching resistance due to the lack of in-situ liquid-phase crosslinking and element segregation. The embodiments utilize macromolecular crosslinking and a two-step sintering process to distribute yttrium as a discontinuous nanoscale isolated phase. This micro-discrete structure weakens the local barrier effect, enabling uniform consumption of the material as a whole, and suppressing the increase in roughness and particle shedding. The single-step high-temperature sintering of Comparative Example 5 leads to coarsening of the secondary phase and continuity of the grain boundary network, further reducing the anti-powdering performance, which further proves the effectiveness of the two-step sintering method of the present invention in maintaining the micro-discrete structure and improving etching resistance.

[0079] Test Example 6: This test example provides experimental verification of the high-temperature electrical performance and insulation reliability mechanism of the present invention. The experimental subjects were ceramic sintered bodies prepared in Examples 1 to 5, as well as Comparative Examples 1, 4, and 5, to investigate the actual effects of different impurity residue levels and microscopic grain boundary network topology on the insulation properties of the dielectric layer in extreme thermodynamic service environments.

[0080] The specific test procedures for high-temperature volume resistivity and dielectric breakdown strength are as follows: Each batch of sintered ceramic bodies was processed into standard circular samples with a diameter of 30 mm and a thickness strictly controlled at 1.00 ± 0.02 mm. The sample surface was cleaned alternately with acetone and anhydrous ethanol in an ultrasonic cleaner for 15 minutes each time to remove processing residues. After drying, pure gold circular films with a diameter of 20 mm were deposited in the central area of ​​both the upper and lower surfaces of the sample using a magnetron sputtering device as test electrodes.

[0081] When conducting high-temperature volume resistivity testing, the sample with electrodes is placed in a high-temperature probe station equipped with a heating platform. The test chamber is sealed and filled with high-purity nitrogen for protection. The heating platform is heated to 200°C at a rate of 5°C / min and held at that temperature for 30 minutes to ensure thermal equilibrium is reached inside the sample. A DC voltage of 1000V is applied across the sample using a high-resistivity meter. After continuous polarization for 60 seconds, a stable leakage current value is read. The volume resistivity of the material at 200°C is calculated by combining the sample's electrode area and thickness geometry.

[0082] When conducting high-temperature dielectric breakdown strength tests, the sample is immersed in a special high-temperature insulating silicone oil bath preheated and kept at a constant temperature of 200°C. A spherical-surface electrode system is used to clamp the sample. The voltage boost mode of the withstand voltage tester is set to continuous DC boost, with the boost rate controlled at 0.5 kV / s, and leakage current in the circuit is monitored in real time. When the system detects a sudden overload of current (typically with a threshold of 5 mA), it is determined that the sample has undergone a through-breakdown. The ultimate breakdown voltage at this moment is recorded, and divided by the actual measured thickness of the sample to obtain the dielectric breakdown strength test value.

[0083] Table 6: Test data of electrical insulation performance of each group of samples at 200℃ high temperature. According to Table 6 and Figure 8 and Figure 9 Comparative Example 4 showed significant electrical degradation at 200℃, with its volume resistivity decreasing to 8.63 × 10⁻⁶. 10 The dielectric breakdown strength is only 16.8 kV / mm, measured in Ω·cm. Analysis of residual carbon data indicates that the high content of free carbon within the sample forms a low-impedance leakage path under a high-temperature electric field, potentially leading to localized thermal breakdown. The examples used wet oxygen-assisted debinding to reduce free carbon and maintain insulation levels. Simultaneously, the electrical properties of Comparative Examples 1 and 5 also showed a significant decrease, attributed to the formation of a continuous yttrium-rich grain boundary network within the samples. Continuous grain boundaries in multiphase ceramics accumulate defects such as oxygen vacancies, forming charge migration channels with high ionic conductivity under thermal excitation. In contrast, Examples 1 to 5, through liquid-phase crosslinking and heat treatment optimization, dispersed yttrium in a discontinuous nanophase form at the grain boundaries, disrupting the continuous transport path of charge carriers. This discrete structure increases the electron migration barrier, enabling the material to maintain a breakdown strength of nearly 40 kV / mm and high volume resistivity under high temperature and pressure conditions, demonstrating stable insulation reliability.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A plasma corrosion-resistant composite dielectric layer electrostatic chuck, characterized in that, The composite dielectric layer of the electrostatic chuck is sintered from composite granulated powder; the yttrium element inside the composite dielectric layer is discretely distributed at the alumina grain boundaries in the form of discontinuous nanoscale isolated phases, thereby avoiding the formation of a continuous yttrium-rich grain boundary network to suppress anisotropic etching. The composite granulated powder is made from raw materials comprising the following parts by weight: Yttrium acetate tetrahydrate: 29.9-149.7 parts; Basic aluminum acetate 31.8-95.4 parts; Citric acid monohydrate: 59.8-433.5 parts; 10-30 parts of polyethylene glycol; 5-15 parts of polyvinyl alcohol; 920-980 parts of high-purity alumina powder.

2. The plasma-resistant composite dielectric layer electrostatic chuck according to claim 1, characterized in that, The composite granulated powder is preferably made from raw materials comprising the following parts by weight: 89.8 parts of yttrium acetate tetrahydrate; 63.6 parts of basic aluminum acetate; and 207.4 parts of citric acid monohydrate. 20 parts polyethylene glycol; 10 parts polyvinyl alcohol; 950 parts of high-purity alumina powder.

3. The plasma-resistant composite dielectric layer electrostatic chuck according to claim 1, characterized in that, The characteristic parameters of the raw material are defined as follows: The high-purity alumina powder has an α-phase microstructure, a purity of not less than 99.99%, a median diameter (D50) between 0.1 μm and 0.5 μm, and a specific surface area of ​​5 m². 2 / g to 15m 2 Between / g; The polyethylene glycol has free hydroxyl groups at both ends and a number average molecular weight between 2,000 and 4,000. The degree of alcoholysis of the polyvinyl alcohol is 88%, and the average degree of polymerization is 1700.

4. A plasma-resistant composite dielectric layer electrostatic chuck according to claim 1 or 2, characterized in that, The composite granulated powder has a polyester crosslinking network formed by the in-situ esterification and polycondensation reaction of the residual carboxyl groups of the monohydrate citric acid and the terminal hydroxyl groups of the polyethylene glycol. Furthermore, the relative density of the composite dielectric layer is ≥99.47%, the internal free residual carbon content is ≤25ppm, and the volume resistivity at 200℃ is ≥3.74×10⁻⁶. 14 Ω·cm.

5. A method for preparing a plasma-resistant composite dielectric layer electrostatic chuck according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Yttrium acetate tetrahydrate, basic aluminum acetate and citric acid monohydrate are coordinated and complexed in an aqueous phase, followed by the addition of polyethylene glycol, polyvinyl alcohol and high-purity alumina powder to prepare a slurry, and the composite granulated powder is prepared by spray drying and granulation. S2. The composite granulated powder is loaded into a mold for pre-forming, followed by cold isostatic pressing, and then demolded to obtain a ceramic blank. S3. The ceramic blank is heated, and humidified air is continuously introduced into the furnace during the heat preservation period to carry out debinding and decarburization treatment. S4. After the glue removal is completed, switch to dry air and heat to the first temperature T1 for preliminary densification. Then, cool to the second temperature T2 for long-term sintering. After cooling, grind and polish to obtain the composite dielectric layer of the electrostatic chuck.

6. The preparation method according to claim 5, characterized in that, The specific implementation method of step S1 is as follows: The yttrium acetate tetrahydrate and basic aluminum acetate were dissolved in deionized water to obtain a mixed metal salt solution; after dissolving in citric acid monohydrate, ammonia was added dropwise to adjust the pH of the system to 4.5-5.5, and the mixture was stirred continuously at room temperature for 1-2 hours to form a complex solution. Polyethylene glycol and polyvinyl alcohol were added to the complexing solution and heated to 60°C with stirring to dissolve. Then, the high-purity alumina powder was added and transferred to a zirconia ball mill. Deionized water was added to adjust the solid content to 50wt%-60wt%. The mixture was ball-milled for 12-24 hours to prepare a homogeneous ceramic slurry.

7. The preparation method according to claim 6, characterized in that, In step S1, the process of feeding the ball-milled ceramic slurry into a centrifugal spray drying tower for atomization granulation is set with the following process parameters: The inlet air temperature is 150℃-180℃, the outlet air temperature is 90℃-110℃, and the atomizing disc speed is controlled at 8000-12000r / min; composite granulated powder with a particle size distribution between 30μm and 80μm is collected.

8. The preparation method according to claim 5, characterized in that, The specific process parameters for step S2 are as follows: The composite granulated powder is pre-formed by bidirectional dry pressing under a pressure of 10-30 MPa; after vacuum sealing the pre-formed green body, it is held under pressure for 10-20 minutes in a cold isostatic press at a pressure of 200-250 MPa.

9. The preparation method according to claim 5, characterized in that, In step S3, the specific process parameters for wet oxygen-assisted debinding are as follows: Heat to 400℃-600℃ at a heating rate of 1-2℃ / min, and keep at a constant temperature for 2-4 hours; during the holding period, the relative humidity of the humidified air is controlled at 60%-80%.

10. The preparation method according to claim 5, characterized in that, In step S4, the specific process parameters for the two-step reaction sintering are as follows: The temperature is increased to the first temperature T1 at a heating rate of 3-5℃ / min, where the first temperature T1 is 1380℃-1420℃, and then kept at the temperature for 1-2 hours. The temperature was then rapidly reduced to a second temperature T2 at a rate of 10℃ / min, which was 1280℃-1320℃. At this temperature, a constant-temperature long-term sintering was carried out for 10-15 hours.

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