Preparation method of electrostatic chuck ceramic with low temperature dependence, electrostatic chuck ceramic and electrostatic chuck

Abstract

The invention discloses a preparation method of electrostatic chuck ceramic with low temperature dependence, the electrostatic chuck ceramic and an electrostatic chuck. The method comprises the following steps: weighing CaO powder, SiO2 powder and MgO powder according to a weight ratio, and mixing to obtain mixed powder; the mixed powder is sequentially subjected to ball milling, drying, melting, quenching and smashing, and non-crystallized mixed powder is obtained; weighing aluminum oxide powder, non-crystallized mixed powder, MgO powder and Y2O3 powder according to the weight ratio; mixing the weighed powder, adding a solvent, a dispersing agent, a binder and a plasticizer, and carrying out ball milling and vacuum defoaming to obtain tape casting slurry; preparing the tape casting slurry into a ceramic raw ceramic chip through a tape casting process; and performing lamination and isostatic pressing on the ceramic green ceramic chips to obtain the ceramic forming body. The electrostatic chuck ceramic prepared by the invention has relatively low temperature dependence, and when the electrostatic chuck ceramic is suitable for an electrostatic chuck, the electrostatic chuck ceramic can be stably adsorbed and desorbed in a relatively large temperature range.

Description

Technical Field

[0001] The present application relates to the technical field of the preparation of electrostatic chuck ceramic plates, and particularly to a method for preparing an electrostatic chuck ceramic with low temperature dependence, an electrostatic chuck ceramic, and an electrostatic chuck. Background Art

[0002] Generally, semiconductor devices or display panel devices are manufactured by sequentially stacking multiple thin film layers including a dielectric layer and a metal layer on a glass substrate, a flexible substrate, or a semiconductor wafer substrate, and then performing repair. These thin film layers are sequentially deposited on the substrate by a CVD process or a PVD process. To perform these semiconductor manufacturing processes, an electrostatic chuck is used in the cavity of a semiconductor manufacturing device to support and fix the substrate.

[0003] Electrostatic chucks are divided into Johnsen-Rahbek type (also known as J-R type) electrostatic chucks and Coulomb type electrostatic chucks. Both types of electrostatic chucks fix the substrate by the attraction of opposite static charges, and there is a dielectric layer on the surface of both types of electrostatic chucks that contacts the substrate. The dielectric layer is generally ceramic.

[0004] In some applications, it is required that the electrostatic chuck be processed at room temperature (e.g., 25°C), while in other applications, it is required that the electrostatic chuck be processed at a higher temperature (e.g., 150°C). However, generally, due to the resistivity of the dielectric layer changing with temperature, a single electrostatic chuck cannot be applicable to a large temperature range. Especially in the dry etching process, the ceramic electrostatic chuck mainly used in the polysilicon etching process, due to the use of a laminated ceramic electrostatic chuck, from room temperature to a temperature rise of 100 - 150°C, the electrostatic force changes from Coulomb force to J-R force, the electrostatic force increases significantly, and the discharge time of the residual charge is longer, resulting in difficult etching reactions. Similarly, as the composition of the ceramic electrostatic chuck, the temperature dependence of the material physical properties increases, resulting in structural defects and becoming the cause of the decline of electrical / mechanical physical properties.

[0005] Therefore, developing a ceramic material that can balance low sintering temperature and low temperature dependence is of great significance for improving the performance of electrostatic chucks. Summary of the Invention

[0006] To solve the above technical problems, the present application provides a method for preparing an electrostatic chuck ceramic with low temperature dependence, an electrostatic chuck ceramic, and an electrostatic chuck, so as to reduce the temperature dependence of the electrostatic chuck ceramic and improve the performance of the electrostatic chuck.

[0007] The first object of the present application is to provide a method for preparing an electrostatic chuck ceramic with low temperature dependence.

[0008] The above object 1 of the present application is achieved by the following technical solutions:

[0009] A method for preparing an electrostatic chuck ceramic with low temperature dependence, comprising the following steps:

[0010] S1, weighing CaO powder, SiO 2 powder and MgO powder according to a weight ratio and mixing them to obtain a mixed powder;

[0011] S2, successively ball-milling, drying, melting, quenching and pulverizing the mixed powder to prepare an amorphous mixed powder;

[0012] S3, weighing alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder;

[0013] S4, mixing the weighed alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder, adding a solvent, a dispersant, a binder and a plasticizer, and then performing ball-milling and vacuum degassing to obtain a casting slurry;

[0014] S5, preparing the casting slurry into a green ceramic sheet by a casting process;

[0015] S6, obtaining a ceramic formed body by laminating and isostatic pressing the green ceramic sheet;

[0016] S7, sintering the ceramic formed body to obtain an electrostatic chuck ceramic.

[0017] Preferably, in step S2, the process of successively ball-milling, drying, melting, quenching and pulverizing the mixed powder to prepare an amorphous mixed powder includes:

[0018] S21, ball-milling the mixed powder for 4 h to make it evenly mixed;

[0019] S22, putting the evenly mixed mixed powder into an oven for drying, the drying temperature is 120 °C, and the drying time is 6 h;

[0020] S23, melting the dried mixed powder to obtain a melt, the melting temperature is 1450 °C to 1600 °C, and the heat preservation time is 2 h;

[0021] S24, immediately taking out the melt after heat preservation and pouring it into pure water for quenching to obtain a glassy solid;

[0022] S25, ball-milling and pulverizing the glassy solid for 9 - 12 h to obtain the amorphous mixed powder.

[0023] Preferably, in step S1, the weight ratio of the CaO powder, SiO 2 powder and MgO powder is CaO powder:SiO 2 powder:MgO powder = 35 - 48:34 - 50:11 - 18.

[0024] Preferably, the weight ratio of the CaO powder, SiO 2 powder and MgO powder is CaO powder:SiO 2 powder:MgO powder = 35:50:15.

[0025] Preferably, in step S3, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder and the Y 2 O 3 powder is alumina powder:devitrified mixed powder:MgO powder:Y 2 O 3 powder = 94 - 98:1 - 3:0.5 - 1.5:0.5 - 1.5.

[0026] Preferably, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder and the Y 2 O 3 powder is alumina powder:devitrified mixed powder:MgO powder:Y 2 O 3 powder = 96:1.8:1.2:1.

[0027] Preferably, in step S4, the mixing of the weighed alumina powder, the devitrified mixed powder, the MgO powder and the Y 2 O 3 powder, adding a solvent, a dispersant, a binder and a plasticizer, and then performing ball milling and vacuum degassing to obtain a casting slurry includes:

[0028] S41, adding the alumina powder, the devitrified mixed powder, the MgO powder, the Y 2 O 3 powder, a dispersant and a binary solvent into a ball mill tank and performing primary ball milling for 10 h to obtain a first slurry;

[0029] S42, adding a binder and a plasticizer to the first slurry in the ball mill tank and performing secondary ball milling for 2 h to obtain a second slurry;

[0030] S43, transferring the second slurry to a degassing machine for vacuum degassing for 4 h to obtain the casting slurry.

[0031] Preferably, in step S7, the sintering of the ceramic green body to obtain an electrostatic chuck ceramic includes:

[0032] In an air or nitrogen atmosphere, the ceramic green body is kept at 600 °C for 180 min for debinding, and then sintered at 1530 °C for 2 h to obtain the electrostatic chuck ceramic.

[0033] The second object of the present application is to provide an electrostatic chuck ceramic.

[0034] The above second object of the present application is achieved by the following technical solution:

[0035] An electrostatic chuck ceramic is prepared by using the method for preparing an electrostatic chuck ceramic with low temperature dependence according to any one of the above first objects.

[0036] The third object of the present application is to provide an electrostatic chuck.

[0037] The above third object of the present application is achieved by the following technical solution:

[0038] An electrostatic chuck, wherein the dielectric layer of the electrostatic chuck is made of the electrostatic chuck ceramic described in the above second object.

[0039] The above technical solution of the present application has the following advantages compared with the prior art:

[0040] By improving the formula, the present application uses a mixed powder of CaO powder, SiO 2 powder and MgO powder as a sintering aid, which can significantly reduce the sintering temperature, improve the density of the ceramic structure, and improve the production efficiency. The non-crystallized mixed powder prepared by successively ball-milling, drying, melting, quenching and pulverizing the mixed powder and the mixture of alumina powder, MgO powder, Y 2 O 3 powder are used as the raw materials for preparing the electrostatic chuck ceramic, effectively improving the temperature dependence of the electrostatic chuck ceramic. In a relatively large temperature range, the volume resistivity of the ceramic changes little, and the resistance change range remains small, so that the prepared electrostatic chuck has a stable adsorption force and efficient and controllable desorption performance, and can stably adsorb and desorb in a relatively large temperature range. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic structural diagram of a preparation method of an electrostatic chuck ceramic with low temperature dependence in an embodiment of the present application;

[0043] Figure 2 It is a schematic flow diagram of a preparation method of a non-crystallized mixed powder in an embodiment of the present application. Detailed implementation manners

[0044] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0045] In the embodiments provided by the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are only illustrative. For example, the division of units and modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or modules can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed with each other can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0046] In addition, each functional unit in the embodiments of the present application can be all integrated in a processor, or each unit can be separately used as a device, or two or more units can be integrated in a device; each functional unit in the embodiments of the present application can be implemented in the form of hardware, or in the form of a combination of hardware and software functional units.

[0047] Those of ordinary skill in the art can understand that all or part of the steps of implementing the following method embodiments can be completed through program instructions and related hardware. The foregoing program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the following method embodiments are executed; and the foregoing storage medium includes: various media that can store program codes such as removable storage devices, read-only memories (ROMs), magnetic disks, or optical discs.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more such features. In the description of this application, the meaning of "a plurality" and "several" is two or more, unless otherwise specifically defined.

[0049] As Figure 1 shown, an embodiment of this application provides a method for preparing an electrostatic chuck ceramic with low temperature dependence, and this method may include the following steps:

[0050] S1, Weigh CaO powder, SiO 2 powder and MgO powder according to the weight ratio and mix them to obtain a mixed powder;

[0051] S2, Grind, dry, melt, rapidly cool and pulverize the mixed powder in sequence to prepare an amorphous mixed powder;

[0052] S3, Weigh alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder;

[0053] S4, Mix the weighed alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder, add a solvent, a dispersant, a binder and a plasticizer, then grind and degas under vacuum to obtain a casting slurry;

[0054] S5, Prepare the casting slurry into a green ceramic sheet through a casting process;

[0055] S6, Prepare a ceramic formed body through laminating and isostatic pressing of the green ceramic sheet; that is, laminate the thinner green ceramic sheets into a green body with a thickness of about 3.5 mm through a laminating process, and an electrode layer is added. The electrode layer is made by screen-printing a metal electrode onto the green ceramic sheet. The green body removes voids through warm isostatic pressing to increase density and strength and form a formed body.

[0056] S7, Sinter the ceramic formed body to obtain an electrostatic chuck ceramic.

[0057] As Figure 2 shown, in one embodiment, in step S2, grinding, drying, melting, rapidly cooling and pulverizing the mixed powder in sequence to prepare an amorphous mixed powder includes:

[0058] S21, Grind the mixed powder for 4 h to make it evenly mixed;

[0059] S22. Put the uniformly mixed powder into an oven for drying at a drying temperature of 120 °C for 6 h;

[0060] S23. Melt the dried mixed powder to obtain a melt at a melting temperature of 1450 °C to 1600 °C and hold for 2 h;

[0061] S24. Immediately take out the melt after the heat preservation and pour it into pure water for rapid cooling to obtain a glassy solid;

[0062] S25. Ball-mill and pulverize the glassy solid for 9 to 12 h to obtain an amorphous mixed powder.

[0063] In one embodiment, in step S1, the weight ratio of CaO powder, SiO 2 powder and MgO powder is CaO powder:SiO 2 powder:MgO powder = 35 - 48:34 - 50:11 - 18.

[0064] In one embodiment, the weight ratio of CaO powder, SiO 2 powder and MgO powder is CaO powder:SiO 2 powder:MgO powder = 35:50:15.

[0065] In one embodiment, in step S3, the weight ratio of alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder is alumina powder:amorphous mixed powder:MgO powder:Y 2 O 3 powder = 94 - 98:1 - 3:0.5 - 1.5:0.5 - 1.5.

[0066] In one embodiment, the weight ratio of alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder is alumina powder:amorphous mixed powder:MgO powder:Y 2 O 3 powder = 96:1.8:1.2:1.

[0067] In one embodiment, in step S4, weigh the alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder, mix them, add a solvent, a dispersant, a binder and a plasticizer, then ball-mill and degas under vacuum to obtain a casting slurry including:

[0068] S41. Add alumina powder, amorphous mixed powder, MgO powder, Y 2O 3 After adding powder, dispersant and binary solvent and performing ball milling for 10 h, the first slurry is obtained.

[0069] Specifically, the dispersant can be one of ammonium polycarboxylate, fatty alcohol polyoxyethylene ether and castor oil, and the binary solvent can be one of ethanol / toluene and isopropanol / cyclohexanone.

[0070] S42, Add binder and plasticizer to the first slurry in the ball mill tank and perform secondary ball milling and mixing for 2 h to obtain the second slurry.

[0071] Specifically, the binder can be one of polyvinyl butyral and polymethyl methacrylate, and the plasticizer can be one or two of dibutyl phthalate, butyl benzyl phthalate and polyethylene glycol.

[0072] S43, Transfer the second slurry to a defoamer for vacuum defoaming for 4 h to obtain a casting slurry.

[0073] In one embodiment, in step S7, sintering the ceramic green body to obtain an electrostatic chuck ceramic includes:

[0074] In an air or nitrogen atmosphere, the ceramic green body is held at 600 °C for 180 min for debinding, and then held at 1530 °C for 2 h for sintering to obtain an electrostatic chuck ceramic.

[0075] Since in the composition of the electrostatic chuck with a ceramic dielectric layer, the temperature dependence of the material physical properties increases, the electrostatic force changes from Coulomb force to J-R force as the use temperature increases, the electrostatic force increases significantly, the discharge time of the residual charge is long, and an undesired clamping effect is generated. In the embodiment of the present application, by improving the formula, a mixed powder of CaO powder, SiO 2 powder and MgO powder is used as a sintering aid, which can significantly reduce the sintering temperature, improve the ceramic structure density, and improve production efficiency. The non-crystallized mixed powder prepared by successively ball milling, drying, melting, quenching and pulverizing the mixed powder and the mixture of alumina powder, MgO powder, Y 2 O 3 powder are used as the raw materials for preparing the electrostatic chuck ceramic, effectively improving the temperature dependence of the electrostatic chuck ceramic. In a relatively large temperature range, the volume resistivity of the ceramic changes little, and the resistance change range is kept small, so that the prepared electrostatic chuck has a stable adsorption force and efficient and controllable desorption property, and can stably adsorb and desorb in a relatively large temperature range.

[0076] In the amorphous mixed powder in the embodiments of the present application, the melting of the amorphous glass at high temperature can promote the densification of the sintered body. During the sintering process, when the temperature reaches the softening point of the glass phase, the glass changes from a solid state to a liquid state, and the flowing glass phase gradually penetrates into the three-dimensional network structure of the ceramic particles, fills the pores, wraps the ceramic particles, and promotes the interconnection between the ceramic particles to form a dense network structure. This is because:

[0077] (1) The amorphous glass ceramic is composed of an amorphous matrix and uniformly distributed crystal phases. The difference in the thermal expansion coefficients between the amorphous matrix and the crystal phases can compensate each other during temperature changes, reducing the overall thermal expansion;

[0078] (2) The atomic arrangement of the amorphous glass is long-range disordered, forming a large number of localized states and trap energy levels. Charge carriers (electrons or ions) need to be transported through thermally activated hopping. This disorder leads to a reduced temperature sensitivity of the conductivity because the distribution of the hopping barriers is relatively wide, and the influence of temperature changes on the overall conductivity is averaged;

[0079] (3) The crystal phase and the amorphous phase form a heterointerface with a high interface density, restricting the migration path of charge carriers and further weakening the temperature dependence of the resistivity;

[0080] (4) The microstructure of the amorphous glass ceramic is uniform, with few internal defects (such as cracks and pores), reducing the performance degradation caused by the expansion of defects during temperature changes.

[0081] The embodiments of the present application also provide an electrostatic chuck ceramic, which is prepared by using the preparation method of the electrostatic chuck ceramic with low temperature dependence described in any of the above embodiments.

[0082] Since the electrostatic chuck ceramic of this embodiment is prepared by using the preparation method of the electrostatic chuck ceramic with low temperature dependence described in any of the above embodiments, therefore, this electrostatic chuck ceramic has the advantages of low temperature dependence, stable adsorption force and efficient and controllable desorption performance.

[0083] The embodiments of the present application also provide an electrostatic chuck, and the dielectric layer of this electrostatic chuck is made of the electrostatic chuck ceramic in the above embodiments.

[0084] Since the electrostatic chuck of this embodiment is made of the electrostatic chuck ceramic with low temperature dependence in the above embodiments, therefore, this electrostatic chuck has stable adsorption force and efficient and controllable desorption performance.

[0085] In order to better understand the advantages of the preparation method of the electrostatic chuck ceramic with low temperature dependence in the embodiments of the present application, the following uses multiple groups of embodiments and multiple groups of comparative examples for comparative analysis to demonstrate and explain its technical effects.

[0086] Specifically, in the following embodiments, when testing the electrostatic chuck ceramic, the ASTM D257 standard test method is adopted, and the test conditions are as follows: the outer diameter is 40 mm, the thickness is 0.5 mm, the voltage is 1 kV, the electric field is 19.5 kV / cm, the volume resistivity of the electrostatic chuck ceramic is tested at different temperatures (25 °C, 50 °C, 100 °C, 150 °C), and the test duration is 60 s.

[0087] Example 1:

[0088] 1. Weigh CaO powder, SiO 2 powder and MgO powder in a weight ratio of 35:50:15 and mix them to obtain a mixed powder;

[0089] 1'. The mixed powder is successively ball-milled, dried, melted, quenched and pulverized to prepare an amorphous mixed powder. The specific process is as follows:

[0090] (1). Ball-mill the mixed powder for 4 h to make it evenly mixed;

[0091] (2). Put the evenly mixed powder into an oven for drying. The drying temperature is 120 °C and the drying time is 6 h;

[0092] (3). Melt the dried mixed powder to obtain a melt. The melting temperature is 1450 °C to 1600 °C and the holding time is 2 h;

[0093] (4). Immediately take out the melt after the holding is over and pour it into pure water for quenching to obtain a glassy solid;

[0094] (5). Ball-mill and pulverize the glassy solid for 9 - 12 h to obtain an amorphous mixed powder.

[0095] 2. Weigh alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder in a weight ratio of 96:1.8:1.2:1;

[0096] 3. Mix the weighed alumina powder, amorphous mixed powder, MgO powder and Y 2 O 3 powder, and then ball-mill and vacuum degas them to obtain a casting slurry. The specific process is as follows:

[0097] a. Add alumina powder, amorphous mixed powder, MgO powder, Y 2 O 3 powder, a dispersant and a binary solvent into a ball-mill tank and conduct primary ball-milling and mixing for 10 h to obtain a first slurry;

[0098] b. Add a binder and a plasticizer to the first slurry in the ball mill, and perform secondary ball milling and mixing for 2 h to obtain a second slurry.

[0099] c. Transfer the second slurry to a defoamer for vacuum defoaming for 4 h to obtain a casting slurry.

[0100] 4. Prepare a ceramic green sheet from the casting slurry by a casting process.

[0101] 5. Obtain a ceramic formed body by laminating and isostatic pressing the ceramic green sheet.

[0102] 6. Sinter the ceramic formed body to obtain an electrostatic chuck ceramic. The specific process is as follows:

[0103] In an air or nitrogen atmosphere, keep the ceramic formed body at 600 °C for 180 min for debinding, and then keep it at 1530 °C for 2 h for sintering to obtain the electrostatic chuck ceramic.

[0104] Example 2:

[0105] In step 1, the weight ratio of the CaO powder, SiO 2 powder and MgO powder is 41:48:11, and the remaining steps are the same as those in Example 1.

[0106] Example 3:

[0107] In step 1, the weight ratio of the CaO powder, SiO 2 powder and MgO powder is 48:34:18, and the remaining steps are the same as those in Example 1.

[0108] Example 4:

[0109] In step 2, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder and the Y 2 O 3 powder is 98:1:0.5:0.5, and the remaining steps are the same as those in Example 1.

[0110] Example 5:

[0111] In step 2, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder and the Y 2 O 3 powder is 94:3:1.5:1.5, and the remaining steps are the same as those in Example 1.

[0112] Comparative Example 1:

[0113] The specific process is as follows:

[0114] 1. Weigh CaO powder, SiO2 The powder and MgO powder are mixed to obtain a mixed powder;

[0115] 2. Alumina powder, mixed powder, MgO powder and Y are weighed according to a weight ratio of 96:1.8:1.2:1 2 O 3 powder;

[0116] 3. The weighed alumina powder, mixed powder, MgO powder and Y 2 O 3 powder are mixed and then ball milled and vacuum degassed to obtain a casting slurry. The specific process is as follows:

[0117] a. Alumina powder, mixed powder, MgO powder, Y 2 O 3 powder, a dispersant and a binary solvent are added to a ball mill jar and then ball milled for 10 h for the first time to obtain a first slurry;

[0118] b. A binder and a plasticizer are added to the first slurry in the ball mill jar and then ball milled for the second time for 2 h to obtain a second slurry;

[0119] c. The second slurry is transferred to a degassing machine for vacuum degassing for 4 h to obtain a casting slurry.

[0120] 4. The casting slurry is prepared into a green ceramic sheet through a casting forming process;

[0121] 5. A ceramic formed body is obtained through laminating and isostatic pressing of the green ceramic sheet;

[0122] 6. The ceramic formed body is sintered to obtain an electrostatic chuck ceramic. The specific process is as follows:

[0123] In an air or nitrogen atmosphere, the ceramic formed body is kept at 600 °C for 180 min for debinding, and then kept at 1530 °C for 2 h for sintering to obtain an electrostatic chuck ceramic.

[0124] That is, for Comparative Example 1, compared with Example 1, the mixed powder is not subjected to non-crystallization treatment, and the subsequent steps are directly carried out using the mixed powder in Step 1.

[0125] Comparative Example 2:

[0126] In Step 1, the weight ratio of CaO powder, SiO 2 powder and MgO powder is 40:55:5, and the remaining steps are the same as those in Example 1.

[0127] Comparative Example 3:

[0128] In Step 1, CaO powder, SiO 2The weight ratio of the powder and MgO powder is 25:40:35, and the remaining steps are the same as those in Example 1.

[0129] Comparative Example 4:

[0130] In Step 2, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder, and the Y 2 O 3 powder is 90:4:3:3, and the remaining steps are the same as those in Example 1.

[0131] Comparative Example 5:

[0132] In Step 2, the weight ratio of the alumina powder, the devitrified mixed powder, the MgO powder, and the Y 2 O 3 powder is 99:0.5:0.2:0.3, and the remaining steps are the same as those in Example 1.

[0133] The comparison table of the test results of the above 5 examples and 5 comparative examples is as follows:

[0134]

[0135]

[0136]

[0137] From the comparison of the volume resistivity in the test results of the above table, it can be seen that:

[0138] Comparing Example 1 with Comparative Example 1, in Example 1, the devitrified mixed powder is used, and the volume resistivity of the electrostatic chuck ceramic obtained has a smaller change in the temperature range of 20°C to 150°C. When the temperature is 20°C and 150°C, the volume resistivity difference is only about 5 times (in Comparative Example 1, when the temperature is 20°C and 150°C, the volume resistivity difference is nearly 500 times), indicating that using the devitrified mixed powder significantly reduces the temperature dependence of the ceramic.

[0139] Comparing Example 1 with Examples 2 and 3, using the weight ratio of the CaO powder, SiO 2 powder and MgO powder corresponding to Example 1 of 35:50:15, the volume resistivity of the obtained electrostatic chuck ceramic has a smaller change in the temperature range of 20°C to 150°C, indicating that the weight ratio of Example 1 is more optimal.

[0140] Comparing Example 1 with Examples 4 and 5, using the alumina powder, the devitrified mixed powder, the MgO powder, and the Y 2 O 3The weight ratio of the powder is 96:1.8:1.2:1. The obtained electrostatic chuck ceramic has a smaller change in volume resistivity within the temperature range of 20°C to 150°C, indicating that the weight ratio of Example 1 is more optimal.

[0141] Comparing Example 1 with Comparative Example 2 and Comparative Example 3, using the weight ratio of CaO powder, SiO 2 powder and MgO powder corresponding to Example 1 as 35:50:15 (within the range of 35 - 48:34 - 50:11 - 18), while the weight ratios of CaO powder, SiO 2 powder and MgO powder in Comparative Example 2 and Comparative Example 3 are outside the range of 35 - 48:34 - 50:11 - 18. The obtained electrostatic chuck ceramic has a smaller change in volume resistivity within the temperature range of 20°C to 150°C, indicating that the weight ratio of CaO powder, SiO 2 powder and MgO powder corresponding to Example 1 within the range of 35 - 48:34 - 50:11 - 18 is more optimal.

[0142] Comparing Example 1 with Comparative Example 4 and Comparative Example 5, using the weight ratio of alumina powder, non-crystallized mixed powder, MgO powder and Y 2 O 3 powder corresponding to Example 1 as 96:1.8:1.2:1 (within the range of 94 - 98:1 - 3:0.5 - 1.5:0.5 - 1.5), while the weight ratios of alumina powder, non-crystallized mixed powder, MgO powder and Y 2 O 3 powder in Comparative Example 4 and Comparative Example 5 are outside the range of 94 - 98:1 - 3:0.5 - 1.5:0.5 - 1.5. The obtained electrostatic chuck ceramic has a smaller change in volume resistivity within the temperature range of 20°C to 150°C, indicating that the weight ratio of alumina powder, non-crystallized mixed powder, MgO powder and Y 2 O 3 powder corresponding to Example 1 within the range of 94 - 98:1 - 3:0.5 - 1.5:0.5 - 1.5 is more optimal.

[0143] In this specification, each embodiment is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and reference can be made to the description in the method part for relevant parts.

[0144] Those skilled in the art may further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this embodiment can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0145] The steps of the methods or algorithms described in combination with the embodiments disclosed in this embodiment can be directly implemented by hardware, software modules executed by a processor, or a combination of both. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0146] The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined in this embodiment can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown in this embodiment, but rather to the widest scope consistent with the principles and novel features disclosed in this embodiment.

Claims

1. A method for preparing an electrostatic chuck ceramic with low temperature dependence, characterized in that: The steps include: S1, weighing CaO powder, SiO2 powder and MgO powder according to a weight ratio and mixing them to obtain a mixed powder; S2, sequentially ball milling, drying, melting, rapid cooling and crushing the mixed powder to obtain a non-crystallized mixed powder; S3, weighing alumina powder, amorphous mixed powder, MgO powder and Y2O3 powder according to weight ratio; S4, mixing the weighed alumina powder, non-crystallized mixed powder, MgO powder and Y2O3 powder, adding a solvent, a dispersant, a binder and a plasticizer, and then ball milling and vacuum degassing to obtain a casting slurry; S5, preparing a ceramic green sheet from the tape-casting slurry by a tape-casting process; S6, preparing a ceramic formed body by laminating and isostatically pressing the ceramic green sheets; S7, sintering the ceramic formed body to obtain an electrostatic chuck ceramic.

2. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 1, characterized in that: In step S2, the step of sequentially ball milling, drying, melting, quenching and crushing the mixed powder to obtain a non-crystallized mixed powder comprises: S21, ball milling the mixed powder for 4 hours to make it uniformly mixed; S22, putting the mixed powder into an oven for drying at a temperature of 120° C. for a drying time of 6 hours; S23, melting the dried mixed powder to obtain a melt, the melting temperature is 1450° C. to 1600° C., and the heat preservation time is 2 hours; S24, after the heat preservation is completed, the melt is immediately taken out and poured into pure water for rapid cooling to obtain a glassy solid; S25, ball-milling the glassy solid for 9 to 12 hours to obtain the amorphous mixed powder.

3. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 1, characterized in that: In step S1, the weight ratio of the CaO powder, SiO2 powder and MgO powder is 35-48:34-50:11-18.

4. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 3, characterized in that: The weight ratio of the CaO powder, SiO2 powder and MgO powder is 35:50:

15.

5. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 1, characterized in that: In step S3, the weight ratio of the alumina powder, the amorphous mixed powder, the MgO powder and the Y2O3 powder is 94-98:1-3:0.5-1.5:0.5-1.

5.

6. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 5, characterized in that: The weight ratio of the alumina powder, the non-crystallized mixed powder, the MgO powder and the Y2O3 powder is 96: 1.8:1.2:1。 7. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to any one of claims 1 to 6, characterized in that: In step S4, the weighed alumina powder, non-crystallized mixed powder, MgO powder and Y2O3 powder are mixed, and a solvent, a dispersant, a binder and a plasticizer are added, followed by ball milling and vacuum degassing to obtain a casting slurry, which comprises: S41, adding the alumina powder, the non-crystallized mixed powder, the MgO powder, the Y2O3 powder, the dispersant and the binary solvent into a ball milling jar and performing ball milling for 10 hours to obtain a first slurry; S42, adding a binder and a plasticizer to the first slurry in the ball mill jar, and performing secondary ball milling for 2 hours to obtain a second slurry; S43, transferring the second slurry to a degassing machine for vacuum degassing for 4 hours to obtain the casting slurry.

8. The method for preparing an electrostatic chuck ceramic with low temperature dependence according to claim 7, characterized in that: In step S7, sintering the ceramic formed body to obtain an electrostatic chuck ceramic comprises: In an air or nitrogen atmosphere, the ceramic formed body is kept at 600° C. for 180 minutes for debinding, and then kept at 1530° C. for 2 hours for sintering to obtain the electrostatic chuck ceramic.

9. An electrostatic chuck ceramic, characterized in that: The electrostatic chuck ceramic is prepared by the method for preparing an electrostatic chuck ceramic with low temperature dependence according to any one of claims 1 to 8.

10. An electrostatic chuck, characterized in that: The dielectric layer of the electrostatic chuck is made of the electrostatic chuck ceramic according to claim 9.

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