Ceramic slurry, aluminum nitride ceramic material and preparation method thereof, and electrostatic chuck

Abstract

The application provides a ceramic slurry, an aluminum nitride ceramic material and a preparation method thereof, and an electrostatic chuck, and relates to the field of ceramic materials. The components of the ceramic slurry in the application include: aluminum nitride powder, a matrix resistance regulator, and an organic solvent, wherein the particle size distribution range of the aluminum nitride powder is 100-1000 nm; the matrix resistance regulator is a transition metal nitride, and the mass ratio of the matrix resistance regulator to the aluminum nitride powder is less than 0.03%. The aluminum nitride ceramic material prepared by using the ceramic slurry of the application not only can maintain good thermal conductivity, but also can keep the volume resistivity at a suitable range at high temperature, thereby meeting the needs of the electrostatic chuck. The electrostatic chuck containing the aluminum nitride ceramic material of the application can not only ensure the processing precision of a wafer, but also has a wide use temperature range, stable adsorption force and efficient and controllable desorption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ceramic materials, in particular, relates to a ceramic slurry, an aluminum nitride ceramic material and a preparation method thereof, and an electrostatic chuck. BACKGROUND

[0002] An electrostatic chuck (also known as an electrostatic chuck) can clamp a wafer on the chuck through electrostatic adsorption force, and is a wafer clamping tool widely used in modern semiconductor manufacturing. The electrostatic chuck can avoid the technical problem that the traditional mechanical chuck causes irreparable damage to the wafer due to mechanical reasons such as pressure and collision during use, and can also reduce particle contamination and increase the effective processing area of the wafer. At the same time, it also overcomes the defect that the vacuum chuck cannot be applied to a low-pressure environment. The electrostatic chuck needs to have good thermal conductivity and appropriate volume resistivity. Good thermal conductivity is conducive to ensuring that the wafer has good uniformity during processing, which can ensure the processing accuracy of the wafer. The appropriate volume resistivity can make the electrostatic chuck have a wide range of use temperature domain, stable adsorption force and high-efficiency controllable desorption. The electrostatic chuck is divided into Johnsen-Rahbek type (also known as JR type) electrostatic chuck and Coulomb type electrostatic chuck, and both types of electrostatic chuck fix the silicon wafer by attracting each other through electrostatic charge. Both types of chuck have a dielectric layer on the surface in contact with the wafer. The dielectric layer of the Coulomb type electrostatic chuck is an insulator, and an insulating ceramic or the like is usually used to ensure the insulation effect. However, the dielectric layer of the JR type electrostatic chuck has conductivity, which is usually prepared by using conductive ceramic, and the volume resistivity of the dielectric layer is usually required to reach the order of magnitude of 10 9 Ω·cm at 650℃.

[0003] At present, ceramic materials mainly containing aluminum nitride are usually used as the main manufacturing material to prepare the electrostatic chuck to be compatible with the third-generation semiconductor materials, so as to facilitate the processing of the wafer.

[0004] Aluminum nitride has excellent thermal conductivity which is less affected by temperature, and also has a thermal expansion coefficient similar to that of the third-generation semiconductor materials such as SiC and GaN, and can be used as the main manufacturing material of the electrostatic chuck. However, the volume resistivity of aluminum nitride at high temperature cannot meet the electrical performance requirements of the electrostatic chuck, so it is necessary to dope metal powder or metal oxide, nitride, etc. as a resistance adjusting agent in aluminum nitride to configure aluminum nitride ceramic material with aluminum nitride, so as to meet the electrical performance requirements of the electrostatic chuck.

[0005] However, the existing technical problem is that, although the aluminum nitride ceramic material containing the resistance adjusting agent can meet the electrical performance requirement of the electrostatic chuck, due to the large difference in thermal conductivity between the resistance adjusting agent and the aluminum nitride, the resistance adjusting agent distributed in the aluminum nitride ceramic material will seriously affect the propagation of phonons of the thermal conduction carrier, thereby reducing the thermal conductivity of the aluminum nitride ceramic material matrix (usually the thermal conductivity of the ceramic matrix is required to be not less than 180 W / m·k), which will adversely affect the processing precision of the wafer. SUMMARY

[0006] The purpose of the present application is to provide a ceramic slurry, an aluminum nitride ceramic material and a preparation method thereof, and an electrostatic chuck. The aluminum nitride ceramic material prepared by using the ceramic slurry of the present application not only can maintain good thermal conductivity, but also can meet the requirement of the volume resistivity at high temperature of the electrostatic chuck. The electrostatic chuck containing the aluminum nitride ceramic material of the present application can not only ensure the processing precision of the wafer, but also has a wide range of use temperature domain, stable adsorption force and high efficient controllable desorption property.

[0007] In a first aspect, the present application provides a ceramic slurry, which comprises: aluminum nitride powder, matrix resistance adjusting agent, and organic solvent, wherein the particle size distribution range of the aluminum nitride powder is 100-1000 nm; the matrix resistance adjusting agent is a transition metal nitride, and the mass ratio of the matrix resistance adjusting agent to the aluminum nitride powder is less than 0.05%.

[0008] In the above technical solution, the inventors found that, if the ceramic slurry uses a transition metal nitride as the matrix resistance adjusting agent, even if the amount of the resistance adjusting agent is greatly reduced, the volume resistivity of the aluminum nitride ceramic material prepared by using the ceramic slurry can be maintained within a suitable range at high temperature, thereby meeting the requirement of the electrostatic chuck. Therefore, even at a higher use temperature, the adsorption and desorption properties of the electrostatic chuck prepared by using the ceramic slurry to the wafer are also more efficient and controllable. In addition, since the amount of the transition metal nitride added is trace amount and is relatively suitable for the aluminum nitride ceramic material, the amount of the impurity phase in the aluminum nitride ceramic material prepared by using the ceramic slurry of the present application will also be greatly reduced, which can reduce the scattering of phonons, thereby significantly improving the thermal conductivity of the aluminum nitride ceramic material. In addition, the specific surface area of the aluminum nitride powder with a particle size in the range of 100-1000 nm in the ceramic slurry is large, and the sintering activity is high, which has a higher mass transfer efficiency during sintering of the slurry, so that the ceramic material formed after sintering of the ceramic slurry has less pore structure and higher density, which is beneficial to improving the thermal conductivity of the ceramic slurry after sintering.

[0009] By selecting a suitable matrix resistance regulator and controlling the particle size of the ceramic slurry, even if a small amount of matrix resistance regulator is added, the volume resistivity of the ceramic slurry after sintering can be controlled within a suitable range; at the same time, since the matrix resistance regulator is compatible with the aluminum nitride powder and the amount added is small, the ceramic material obtained after sintering of the ceramic slurry can still maintain good thermal conductivity.

[0010] In a possible implementation, the content of oxygen impurities in the aluminum nitride powder is not more than 1wt%; and / or, the content of carbon impurities in the aluminum nitride powder is not more than 800ppm.

[0011] In the above technical solution, the ceramic slurry containing the aluminum nitride powder meeting the above conditions has higher thermal conductivity after sintering.

[0012] In a possible implementation, the matrix resistance regulator includes at least one of VN, TiN, CoN, NiN, TaN; and / or, the mass ratio of the matrix resistance regulator to the aluminum nitride powder is 0.005% to 0.025%.

[0013] In the above technical solution, the aluminum nitride ceramic material containing the aluminum nitride powder meeting the above conditions can better meet the requirements of the electrostatic chuck after sintering.

[0014] In a possible implementation, the components of the ceramic slurry further include a lattice purifier, the lattice purifier includes at least two of rare earth metal oxides, rare earth metal fluorides, alkali metal oxides, lithium halides, and the mass ratio of the lattice purifier to the aluminum nitride powder is not more than 3%; optionally, the lattice purifier includes at least two of Y2O3, YF3, Li2O.

[0015] In the above technical solution, the lattice purifier in the ceramic slurry can form a viscous liquid phase under high-temperature sintering conditions, wet the aluminum nitride grains, and effectively remove impurity oxygen on the surface or in the lattice of the aluminum nitride grains, so that the ceramic slurry has better thermal conductivity after sintering. Moreover, the lattice purifiers such as rare earth metal oxides, rare earth metal fluorides, alkali metal oxides, and lithium halides have high affinity for oxygen, so that the lattice purifier can remove impurity oxygen on the surface or in the lattice of the aluminum nitride grains during high-temperature sintering, thereby achieving the purposes of removing impurity oxygen from the aluminum nitride grains and purifying the lattice, improving the lattice integrity of the aluminum nitride during sintering, and reducing the generation of aluminum vacancies, thereby improving the thermal conductivity of the ceramic slurry after sintering.

[0016] In addition, the use of a multi-element system lattice purifier can form a specific distribution uniform crystalline phase YAM, YAP with impurity oxygen and the added lattice purifier, which can more effectively improve the thermal conductivity and electrical properties of the aluminum nitride ceramic material.

[0017] In a possible implementation, the organic solvent includes at least one of ethanol, benzene.

[0018] In the technical solution, the organic solvent can disperse and dissolve the solutes.

[0019] In a possible implementation, the components of the ceramic slurry further include a dispersant and a binder; optionally, the dispersant includes at least one of castor oil, glyceryl trioleate, fish oil; and optionally, the binder includes at least one of polyvinyl butyral, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone.

[0020] In the technical solution, the dispersant can reduce the attraction between the nano-powders and reduce the agglomeration phenomenon, so that the ceramic slurry is uniformly dispersed; and the binder can play a role in adhesion, increase the particle size of the pseudo-particles, and increase the particle strength, so that the green body of the ceramic has high density.

[0021] In a second aspect, the application provides an aluminum nitride ceramic material formed by sintering the ceramic slurry.

[0022] In the technical solution, the aluminum nitride ceramic material formed by sintering the ceramic slurry has good thermal conductivity and certain volume resistivity; and the electrostatic chuck prepared by using the aluminum nitride ceramic material as a main material can not only ensure the processing precision of the wafer, but also has a wide use temperature range, stable adsorption force, and high-efficiency controllable desorption.

[0023] In a third aspect, the application provides a preparation method of an aluminum nitride ceramic material, which includes the following steps: spraying and granulating the ceramic slurry to press a green body of the ceramic, then performing degassing on the green body of the ceramic, and then performing hot-pressing sintering and hot-isostatic pressing sintering.

[0024] In the technical solution, when the aluminum nitride ceramic material is prepared, the hot-pressing sintering is performed first, and then the hot-isostatic pressing sintering is performed, so that the diffusion and mass transfer between atoms can be promoted under high temperature and high pressure, the porosity and defects of the aluminum nitride ceramic material can be reduced, and the density of the aluminum nitride ceramic material can be improved. In addition, the hot-isostatic pressing treatment can also optimize the microstructure of the aluminum nitride ceramic material, adjust the grain size, shape, and distribution, and improve the thermal and electrical properties of the aluminum nitride ceramic material.

[0025] In a possible implementation, the temperature during the hot-pressing sintering is 1500-1800℃, and the pressure is 5-30MPa; and the temperature during the hot-isostatic pressing sintering is 1300-1700℃, and the pressure is 100-200MPa.

[0026] In a fourth aspect, the application provides an electrostatic chuck provided with a dielectric layer, and the dielectric layer is prepared from the aluminum nitride ceramic material of the second aspect.

[0027] In the above technical solution, the dielectric layer made of aluminum nitride ceramic material in the second aspect has good thermal conductivity and suitable volume resistivity at high temperature. The electrostatic chuck with this dielectric layer has a wide operating temperature range, stable adsorption force and efficient and controllable desorption. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The image shows the XRD pattern of the aluminum nitride ceramic material in Example 1 of this application.

[0030] Figure 2 This is a SEM image of the aluminum nitride ceramic material in Example 1 of this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0032] The ceramic slurry, aluminum nitride ceramic material and its preparation method, and electrostatic chuck of the embodiments of this application will be described in detail below.

[0033] The ceramic slurry in this embodiment comprises aluminum nitride powder, matrix resistance modifier, organic solvent, lattice purifier, dispersant, and binder. The specific properties and functions of each component are as follows:

[0034] The ceramic slurry of this application contains aluminum nitride powder with a particle size of 100-1000 nm (aluminum nitride powder with this particle size can also be called "nano-sized aluminum nitride powder") and a matrix resistance modifier, wherein the matrix resistance modifier is a transition metal nitride and the mass ratio of the matrix resistance modifier to the aluminum nitride powder is less than 0.03%.

[0035] In the ceramic slurry of this application, aluminum nitride has good and stable thermal conductivity, and also has a coefficient of thermal expansion similar to that of third-generation semiconductor materials such as SiC and GaN, and can be used as the main material of ceramic slurry.

[0036] The matrix resistance regulator can adjust the volume resistivity of the ceramic slurry after sintering at high temperature. However, the current matrix resistance regulator has a large difference in thermal conductivity from aluminum nitride, and needs to be added in a large amount. Therefore, after being mixed with aluminum nitride to form a slurry and then sintered, the propagation of phonons of the heat conduction carrier is seriously affected, thereby reducing the thermal conductivity of the material. However, in the embodiments of the present application, the inventors found that when the transition metal nitride is used as the matrix resistance regulator and is matched with the nano-sized aluminum nitride powder, the matrix resistance regulator only needs to account for less than 0.03% of the mass ratio of the aluminum nitride powder, or even 0.005% to 0.025%, to significantly adjust the volume resistivity of the ceramic slurry after sintering at high temperature, thereby meeting the electrical performance requirements of the electrostatic chuck. In particular, when the matrix resistance regulator includes at least one of VN, TiN, CoN, NiN, TaN, etc., the electrostatic chuck made of the ceramic slurry has more efficient and controllable adsorption and desorption properties for the wafer.

[0037] Because the amount of the transition metal nitride added is small, and the transition metal nitride itself is well matched with the nano-sized aluminum nitride powder, compared with the prior art, the amount of impurity phases of the ceramic slurry after sintering in the embodiments of the present application is also greatly reduced, which can reduce the scattering of phonons, thereby maintaining the good thermal conductivity of aluminum nitride. In addition, the aluminum nitride powder with a particle size in the range of 100 to 1000 nm has the advantages of large specific surface area and high sintering activity, and has higher mass transfer efficiency during slurry sintering, so that the ceramic slurry after sintering has fewer pore structures and higher density, which is beneficial to improving the thermal conductivity of the ceramic slurry after sintering.

[0038] In addition, in the embodiments of the present application, the content of oxygen impurities in the aluminum nitride powder can be controlled to be not more than 1 wt%, or the content of carbon impurities in the aluminum nitride powder can be controlled to be not more than 800 ppm, to further improve the thermal conductivity of the ceramic slurry after sintering. If the content of oxygen impurities and carbon impurities in the aluminum nitride powder is to be controlled, the aluminum nitride powder can be prepared by a nitriding reduction reaction, and the specific operation steps of the nitriding reduction reaction for preparing the aluminum nitride powder are not described herein.

[0039] In the embodiments of the present application, the components of the ceramic slurry also include a lattice purifying agent. The lattice purifying agent generally includes at least two of rare earth metal oxides, rare earth metal fluorides, alkali metal oxides, and lithium halides, and the mass ratio of the lattice purifying agent to the aluminum nitride powder is not more than 3%.

[0040] The lattice purifier can form a viscous liquid phase under high-temperature sintering conditions, wet the aluminum nitride grains, and effectively remove the impurity oxygen on the surface or in the lattice of the aluminum nitride grains, so that the ceramic slurry has better thermal conductivity after sintering. Moreover, the lattice purifier such as the rare earth metal oxide, the rare earth metal fluoride, the alkali metal oxide, and the lithium halide has high affinity to oxygen, so that the lattice purifier can remove the impurity oxygen on the surface or in the lattice of the aluminum nitride grains during high-temperature sintering, so as to remove the impurity oxygen from the aluminum nitride grains and purify the lattice, improve the lattice integrity of the aluminum nitride during sintering, reduce the generation of aluminum vacancies, and thus improve the thermal conductivity of the ceramic slurry after sintering. Further, the lattice purifier can include at least two of Y2O3, YF3, and Li2O. The at least two lattice purifiers can form specific, uniformly distributed crystalline phases YAM and YAP with the impurity oxygen, so as to more effectively improve the thermal conductivity and electrical properties of the aluminum nitride ceramic material.

[0041] In the embodiment of the present application, the components of the ceramic slurry further include a dispersant and a binder. The dispersant generally includes at least one of castor oil, glyceryl trioleate, fish oil, etc., and accounts for 0.1% to 1% of the mass of the aluminum nitride powder. The binder generally includes at least one of polyvinyl butyral, polyvinyl alcohol, polyethylene glycol, and polyvinyl pyrrolidone, etc., and accounts for 0.5% to 2% of the mass of the aluminum nitride powder. The dispersant can reduce the attraction between the nano powders, reduce the agglomeration phenomenon, so as to obtain a ceramic slurry with uniformly dispersed components. The binder can play a binding role, increase the particle size of the pseudo-particles, and increase the particle strength, so as to obtain a high-density green body of the ceramic.

[0042] In addition, the ceramic slurry in the embodiment of the present application further contains an organic solvent to play a role in dispersing and dissolving various solutes. The organic solvent is generally at least one of ethanol and benzene.

[0043] The embodiment of the present application further provides an aluminum nitride ceramic material formed by sintering the ceramic slurry. The specific preparation method includes the following steps:

[0044] S100: Forming a ceramic slurry: ball-milling the nano-sized aluminum nitride powder, the matrix resistance modifier, and the organic solvent.

[0045] In this step, the components of the ceramic slurry are generally mixed into a uniform mixed slurry with good fluidity and viscosity on a jar mill in a wet ball-milling manner. The ball-milling time is preferably 1 to 20 hours.

[0046] S200: Forming a green body of the ceramic: spray granulating the ceramic slurry and then compression molding.

[0047] In the above step, the spray granulation is generally performed in a spray granulation tower, and the ceramic slurry after the spray granulation forms spherical powder. The inlet air temperature of the spray granulation tower is preferably 150-200℃. The press forming is generally performed by pre-pressing forming through a dry press machine and then press forming into a ceramic green body through a cold isostatic press machine. In the pre-pressing forming process of the dry press machine, the pressure is preferably 10-50MPa, and the pressure of the cold isostatic press forming is preferably 50-150MPa.

[0048] S300: Forming an aluminum nitride ceramic material: The ceramic green body is degassed, and then hot-press sintering and hot-isostatic sintering are performed.

[0049] In this step, the degassing is generally performed by placing the ceramic green body in a degassing furnace and degassing under the protection of a nitrogen atmosphere. The degassing temperature is preferably 400-800℃.

[0050] The hot-press sintering is performed in a hot-press sintering furnace under the protection of a nitrogen atmosphere. The temperature is preferably 1500-1800℃, and the pressure is preferably 5-30MPa. The hot-isostatic sintering is performed in a hot-isostatic sintering furnace in an argon atmosphere. The temperature is preferably 1300-1700℃, and the pressure is preferably 100-200MPa.

[0051] In this step, the hot-press sintering is performed first, and then the hot-isostatic sintering is performed. This can promote the diffusion and penetration between atoms under high temperature and high pressure conditions, reduce the porosity and defects of the aluminum nitride ceramic material, and improve the density of the aluminum nitride ceramic material. In addition, the hot-isostatic treatment can also optimize the microstructure of the aluminum nitride ceramic material, adjust the grain size, morphology and distribution, and improve the mechanical and electrical properties thereof.

[0052] The aluminum nitride ceramic material in the embodiments of the present application can be used in an electrostatic chuck and used for preparing a dielectric layer of an electrostatic chuck.

[0053] The features and properties of the present application are further described in detail below in combination with embodiments.

[0054] Embodiment 1

[0055] This embodiment provides an aluminum nitride ceramic material, and a preparation method thereof is as follows:

[0056] S100, preparing a ceramic slurry.

[0057] AlN powder with an average particle size of 500 nm, oxygen impurity content of 0.05 wt%, carbon impurity content of 400 ppm, and anhydrous ethanol were put into a nylon ball mill jar in a mass ratio of 1:1. Then, 2 wt% of Y2O3, 0.55 wt% of YF3, 0.05 wt% of Li2O, 0.01 wt% of CoN, 2 wt% of PVB (Polyvinyl Butyral), 0.7 wt% of castor oil were put into the ball mill jar, and the mixture was mixed on a ball mill for 6 h to obtain a ceramic slurry.

[0058] S200, preparing a ceramic green body.

[0059] The ceramic slurry was transported into a spray granulation tower by a peristaltic pump, and spherical powder with a particle size D50 of 85 μm was formed by spray granulation, wherein the inlet air temperature of the spray granulation tower was 180℃, and the outlet air temperature was 80℃. Then, the spherical powder was filled into a stainless steel mold with an inner diameter of φ300 mm, and was pre-pressed by a dry press machine with a single shaft at a pressure of 30 MPa, and then was pressed by a cold isostatic pressing machine at a pressure of 100 MPa, to obtain a ceramic green body with a thickness of 20 mm.

[0060] S300, preparing an aluminum nitride ceramic material.

[0061] The ceramic green body was placed in a debinding furnace and heated to 600℃ at a heating rate of 5℃ / min under nitrogen atmosphere for 5 h for debinding to remove organic components. After debinding, the ceramic green body was first placed in a hot-pressing sintering furnace for hot-pressing sintering, and then was placed in a hot-isostatic pressing sintering furnace for hot-isostatic pressing sintering.

[0062] The hot-pressing sintering was performed under nitrogen protection, and during the hot-pressing sintering, the temperature was first increased to 1000℃ at a rate of 10℃ / min and was kept for 4 h, and then was increased to 1780℃ at a rate of 5℃ / min and was kept for 6 h, and a pressure of 20 MPa was applied during the temperature increasing and keeping; then the temperature was decreased to 1000℃ at a rate of 2℃ / min, and then was cooled to room temperature.

[0063] The hot-isostatic pressing sintering was performed under argon protection, and during the hot-isostatic pressing sintering, the temperature was first increased to 1000℃ at a rate of 8℃ / min and was kept for 2 h, and then was increased to 1600℃ at a rate of 4℃ / min and was kept for 1 h, and a pressure of 120 MPa was applied during the sintering, and then was cooled to room temperature to obtain an aluminum nitride ceramic material.

[0064] Example 2

[0065] The embodiment provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the adding amount of the matrix resistance modifier CoN in the step S100 is 0.015 wt%.

[0066] Embodiment 3

[0067] The embodiment provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the average particle size of the aluminum nitride powder in the step S100 is 950 nm.

[0068] Embodiment 4

[0069] The embodiment provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the same amount of NiN is used instead of CoN as the matrix resistance modifier in the step S100.

[0070] Embodiment 5

[0071] The embodiment provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the YF3 is not added in the step S100.

[0072] Comparative Example 1

[0073] The comparative example provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the distribution particle size of the aluminum nitride powder is 1.8 microns.

[0074] Comparative Example 2

[0075] The comparative example provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the matrix resistance modifier CoN is not added in the step S100.

[0076] Comparative Example 3

[0077] The comparative example provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the same mass of Co2O3 is used instead of CoN as the matrix resistance modifier in the step S100.

[0078] Comparative Example 4

[0079] The comparative example provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the hot isostatic pressing sintering treatment is not performed in the step S300.

[0080] Comparative Example 5

[0081] The comparative example provides an aluminum nitride ceramic material, and the main difference between the preparation method of the aluminum nitride ceramic material and the preparation method of the aluminum nitride ceramic material in the embodiment 1 is that the adding amount of the matrix resistance modifier CoN in the step S100 is 0.07 wt%.

[0082] Sample testing:

[0083] The density of the aluminum nitride ceramic material of each example and the comparative example was tested by gas volume method; the thermal conductivity of the aluminum nitride ceramic material of each example and the comparative example was tested by transient plane source method; the high-temperature volume resistivity of the aluminum nitride ceramic material of each example and the comparative example was tested by high resistance meter + high-temperature insulating material resistivity tester; and the crystalline phase of the aluminum nitride ceramic material of each example and the comparative example was tested by X-ray diffractometer.

[0084] The true density, thermal conductivity, high-temperature volume resistivity and crystalline phase of the aluminum nitride ceramic material of each example and the comparative example are shown in Table 1.

[0085] Table 1: Performance test data of each example and the comparative example

[0086]

[0087] As shown in the table, the thermal conductivity of the aluminum nitride ceramic material in the examples can all reach 180 W / m·K or more, which is significantly higher than the thermal conductivity of the aluminum nitride ceramic material in the comparative example, and the aluminum nitride ceramic material in the examples all has good density; this shows that the aluminum nitride ceramic material formed by sintering the ceramic slurry in the examples of the present application has good thermal conductivity. At the same time, compared with the comparative example, the high-temperature volume resistivity of the aluminum nitride ceramic material in the examples at 650℃ can also reach 10 9 Ω·cm or more, which can well meet the electrical performance requirements of the dielectric layer of the electrostatic chuck.

[0088] The above is only an embodiment of the present application and does not limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A ceramic slurry, characterized in that, Its components include: aluminum nitride powder, matrix resisting agent, lattice purifying agent, and organic solvent, wherein the particle size distribution range of the aluminum nitride powder is 100~1000nm; the matrix resisting agent is a transition metal nitride, and the transition metal nitride includes at least one of VN, TiN, CoN, NiN, and TaN; and the mass ratio of the matrix resisting agent to the aluminum nitride powder is 0.005%~0.025%; the lattice purifying agent includes at least two of rare earth metal oxides, rare earth metal fluorides, alkali metal oxides, and lithium halides, and the mass ratio of the lattice purifying agent to the aluminum nitride powder is not greater than 3% and not equal to 0.

2. The ceramic slurry according to claim 1, characterized in that, The oxygen impurity content in the aluminum nitride powder is no more than 1 wt%. And / or, the carbon impurity content in the aluminum nitride powder is not greater than 800 ppm.

3. The ceramic slurry according to claim 1, characterized in that, The lattice purification agent includes at least two of Y2O3, YF3, and Li2O.

4. The ceramic slurry according to claim 1, characterized in that, The organic solvent includes at least one of ethanol and benzene.

5. The ceramic slurry according to claim 1, characterized in that, Its components also include dispersants and binders; The dispersant includes at least one of castor oil, trioleic acid glyceride, and fish oil; The adhesive includes at least one of polyvinyl butyral, polyvinyl alcohol, polyethylene glycol, and polyvinylpyridinium.

6. An aluminum nitride ceramic material, characterized in that, It is formed by sintering the ceramic slurry as described in any one of claims 1 to 5.

7. A method for preparing an aluminum nitride ceramic material, characterized in that, It includes the following steps: The ceramic slurry according to any one of claims 1 to 5 is spray-granulated and pressed into a ceramic green body. Then, the ceramic green body is debonded and first hot-pressed and sintered, and then hot isostatic pressing and sintering are performed.

8. The method for preparing aluminum nitride ceramic material according to claim 7, characterized in that, The temperature during hot pressing sintering is 1500~1800℃ and the pressure is 5~30MPa; the temperature during hot isostatic pressing sintering is 1300~1700℃ and the pressure is 100~200MPa.

9. An electrostatic chuck, characterized in that, It has a dielectric layer, and the dielectric layer is made of the aluminum nitride ceramic material as described in claim 7.

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