An electrostatic chuck with high dielectric constant and high breakdown strength and its preparation method

Abstract

The present invention relates to an electrostatic chuck with high dielectric constant and high breakdown strength and a preparation method thereof. The electrostatic chuck comprises a ceramic dielectric layer, an adhesive layer and a metal base which are arranged in sequence from top to bottom. The ceramic dielectric layer comprises at least one ceramic dielectric layer. The raw materials of the ceramic dielectric layer include at least one of alumina and aluminum nitride, and at least one of barium titanate, barium zirconate titanate, lead magnesium niobate and barium strontium titanate. The electrostatic chuck utilizes electrostatic adsorption technology to achieve efficient electrostatic adsorption through the ceramic dielectric layer material with high dielectric constant. The high dielectric constant material can effectively store charges, thereby enhancing the electrostatic adsorption force, enabling workpieces such as wafers to maintain better stability and precision during the processing. Moreover, the ceramic dielectric layer material has high breakdown strength, which is beneficial to ensuring the safety of the electrostatic chuck when working in a high-voltage environment. The preparation method is convenient to control and has high production efficiency, which is beneficial to large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor ceramics, and particularly to an electrostatic chuck with high dielectric constant and high breakdown strength and a preparation method thereof. Background Art

[0002] ‌‌The working principle of an electrostatic chuck is based on the adsorption effect of electrostatic force. By applying a high-voltage electric field, the working surface is positively charged while the workpiece is negatively charged, thus generating an electrostatic attraction force that tightly adheres the workpiece to the working surface. It has been widely used in semiconductor processes such as etching, chemical vapor deposition, and ion implantation. When processing a wafer, by applying a charge to the electrode surface of the electrostatic chuck, an electrostatic force is generated, causing the wafer to be adsorbed and fixed on the chuck surface by the electrostatic force. This adsorption method is suitable for a vacuum environment or a plasma environment, which can keep the wafer in better flatness and suppress the deformation of the wafer during the process, so as to improve the stability and reliability of the wafer processing. However, during the manufacturing process, a high-voltage power supply is often required to control the temperature and position of the wafer. Therefore, the electrostatic chuck needs to be able to withstand a higher voltage without breakdown, and there is often a problem that the adsorption firmness of the electrostatic chuck for wafers with high volume resistivity is insufficient, which needs to be solved urgently. Summary of the Invention

[0003] In order to solve the above deficiencies of the prior art, the purpose of the present invention is to provide an electrostatic chuck with high dielectric constant and high breakdown strength. The electrostatic chuck utilizes electrostatic adsorption technology, and realizes efficient electrostatic adsorption through a ceramic dielectric layer material with a high dielectric constant. The high-dielectric-constant material can effectively store charges, thereby enhancing the electrostatic adsorption force, enabling workpieces such as wafers to maintain better stability and accuracy during the processing, and the ceramic dielectric layer material has a high breakdown strength, which is beneficial to ensuring the safety of the electrostatic chuck when working in a high-voltage environment.

[0004] Another purpose of the present invention is to provide a preparation method for an electrostatic chuck with high dielectric constant and high breakdown strength. The preparation method is convenient to control, has high production efficiency, and is conducive to large-scale production; the prepared electrostatic chuck uses a ceramic dielectric layer with high dielectric constant and high breakdown strength, and is safe and reliable to use.

[0005] The purpose of the present invention is achieved through the following technical solutions: An electrostatic chuck with high dielectric constant and high breakdown strength includes a ceramic dielectric layer, a bonding layer, and a metal base arranged in sequence from top to bottom. The ceramic dielectric layer includes at least one ceramic dielectric layer. The raw materials of the ceramic dielectric layer include at least one of alumina (Al2O3) and aluminum nitride (AlN), and include barium titanate (BaTiO3), barium zirconate titanate (BaZr 0.2 Ti 0.8 O3), lead magnesium niobate (MgNb4O 12at least one of lead (Pb) and barium strontium titanate (BaSr(TiO3)2).

[0006] The electrostatic chuck in the present invention mainly includes three parts: a ceramic dielectric layer, an adhesive layer, and a metal base. The ceramic dielectric layer, as the core component of the electrostatic chuck, plays a decisive role in the adsorption force and temperature uniformity of the electrostatic chuck. The metal base mainly provides functions of assembly, load-bearing, and temperature regulation; the adhesive layer is located between the ceramic dielectric layer and the metal base to firmly bond the two. By optimizing the ceramic materials and structures of the ceramic dielectric layer part of the present invention, through formula adjustment and structure improvement, the breakdown strength and dielectric constant of the ceramic dielectric layer are increased, so that the electrostatic chuck can firmly adsorb objects with high volume resistivity, including sapphire, glass, etc., solve the problem of electrostatic adsorption of wafers with relatively high volume resistivity that is difficult to achieve in the prior art, replace mechanical clamping, and improve the product processing yield.

[0007] Further, the ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of alumina, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate.

[0008] Further, the ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of aluminum nitride, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate.

[0009] Further, the adhesive layer is an organic adhesive layer, and the material of the organic adhesive layer is at least one of thermal conductive silicone and epoxy resin.

[0010] Further, the ceramic dielectric layer includes a first ceramic dielectric layer, an adsorption electrode layer, a second ceramic dielectric layer, a heating layer, and a third ceramic dielectric layer which are arranged in sequence from top to bottom. The third ceramic dielectric layer is arranged on the upper end surface of the metal base; the electrostatic chuck is also provided with a plurality of helium holes, and the helium holes penetrate through the lower surface and the upper surface of the ceramic dielectric layer from bottom to top. The upper surface of the first ceramic dielectric layer is provided with a plurality of upwardly protruding protrusions.

[0011] Further, the metal base is provided with a coolant channel and a helium channel communicating with a plurality of helium holes. The helium channel is annular; the adsorption electrode layer and the heating layer are respectively provided with an adsorption electrode lead-out end and a heating electrode lead-out end, and both the adsorption electrode lead-out end and the heating electrode lead-out end extend downward to the lower end of the metal base; the metal base is provided with an adsorption electrode channel for the adsorption electrode lead-out end to pass through and a heating electrode channel for the heating electrode lead-out end to pass through.

[0012] Another object of the present invention is achieved by the following technical solution: A preparation method of the above-mentioned electrostatic chuck with high dielectric constant and high breakdown strength, comprising the following steps: bonding a ceramic dielectric layer and a metal base through an adhesive layer to form an electrostatic chuck.

[0013] Further, the preparation method of the ceramic dielectric layer comprises the following steps:

[0014] (1) Preparation of slurry: According to the raw material composition of the ceramic dielectric layer, take alumina or aluminum nitride and at least one of barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate, and mix them in proportion to obtain a mixed powder; then, by weight, put 90 - 161 parts of the mixed powder, 3 - 7 parts of a sintering aid, 45 - 55 parts of a solvent, and 0.5 - 2.5 parts of a dispersant into a ball mill for ball milling; then add 7 - 11 parts of a binder and 4 - 8 parts of a plasticizer, and continue ball milling; then defoam the ball-milled slurry to obtain a casting slurry with a viscosity of 5000 - 10000 mPa·s; the particle size of the alumina, aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate is 0.2 - 3 μm;

[0015] (2) Casting and cutting: Use a casting machine to form the defoamed casting slurry to obtain a green ceramic tape, and cut it into multiple green ceramic chips;

[0016] (3) Drilling: Process structural holes and positioning hole structures on the green ceramic chips;

[0017] (4) Printing and filling holes: Use a printing and filling machine to perform printing and filling operations of metal slurry on the surface of the drilled green ceramic chips; the main components of the metal slurry include tungsten, molybdenum, and their alloys, and the main function is to provide a conductive path and heat generation;

[0018] (5) Laminating: Stack the printed green ceramic chips and then plastic-seal them; then press the plastic-sealed stacked chips to obtain a green ceramic plate;

[0019] (6) Debinding: Place the green ceramic plate on a corundum-mullite carrier plate, load it into an atmosphere resistance furnace, and slowly heat it to 450 - 650 °C at a heating rate of 0.3 - 1 °C per minute, and hold for 3 - 6 hours to obtain a ceramic debound film;

[0020] (7) Sintering: Sinter the ceramic debound film at a high temperature to obtain a sintered ceramic plate;

[0021] (8) Machining: Machine the sintered ceramic plate to obtain a ceramic dielectric layer.

[0022] The present invention optimizes the ceramic material formula and process of the ceramic dielectric layer of the electrostatic chuck, improves the dispersibility of the ceramic material powder, reduces the grain size of alumina or aluminum nitride ceramics, enhances the thermal, electrical, and mechanical properties of the alumina or aluminum nitride ceramic dielectric layer, and reduces the sintering temperature required. It solves the problems in the prior art that ultra-high purity alumina or aluminum nitride ceramics cannot be prepared, and the products have low strength, poor uniformity, poor quality consistency, and are difficult to sinter.

[0023] Further, in step (1), alumina, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of SiO2, CaO, and MgO; in step (7), the ceramic green sheet is loaded into a high-temperature sintering furnace and sintered at 1500 - 1650 °C for 2 - 4 hours to obtain a sintered ceramic plate.

[0024] Further, in step (1), aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of CeO2, CaO, CaF2, and Y2O3; in step (7), the ceramic green sheet is loaded into a high-temperature sintering furnace and sintered at 1750 - 1850 °C for 2 - 4 hours to obtain a sintered ceramic plate.

[0025] Further, in step (1), the solvent is one or more of ethanol, ethyl acetate, isopropanol, n-butanol, and methyl ethyl ketone; the dispersant is at least one of castor oil, linseed oil, polyethylene glycol, and phosphate ester; the binder is polyvinyl butyral; the plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate, and diisononyl phthalate.

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) When the electrostatic chuck of the present invention is in use, it utilizes electrostatic adsorption technology. By adopting a ceramic dielectric layer of a high dielectric constant ceramic material, efficient electrostatic adsorption is achieved; the ceramic dielectric layer of the electrostatic chuck has a high breakdown strength and a high dielectric constant. The ceramic dielectric layer with a high dielectric constant can better store charges, increase the electric field strength, and have low dielectric loss, enabling the electrostatic chuck to have a strong enough adsorption force to fix low-conductivity materials, preventing them from moving or falling off during the processing, thereby ensuring the accuracy and quality of semiconductor manufacturing; the characteristic of high breakdown strength ensures the safety of the electrostatic chuck when working in a high-voltage environment. During the semiconductor manufacturing process, it is often necessary to use a high-voltage power supply to control the temperature and position of the wafer. The electrostatic chuck with a high breakdown strength can withstand a higher voltage without breakdown, thus ensuring the stability and safety of the processing process.

[0028] (2) The preparation method is convenient to control, has high production efficiency, and is conducive to large-scale production; the obtained electrostatic chuck adopts a ceramic dielectric layer with a high dielectric constant and a high breakdown strength, and is safe and reliable to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic perspective view of the electrostatic chuck of the present invention.

[0030] Figure 2 is a top view of the electrostatic chuck of the present invention.

[0031] Figure 3 is a sectional view of the electrostatic chuck of the present invention.

[0032] Figure 4 is Figure 3 an enlarged view of part A in

[0033] Figure 5 is a schematic structural view of the heating layer.

[0034] Figure 6 is a schematic structural view of the adsorption electrode layer.

[0035] The reference numerals are: 11, metal base; 12, first ceramic dielectric layer; 13, second ceramic dielectric layer; 14, third ceramic dielectric layer; 15, adsorption electrode layer; 16, heating layer; 17, helium hole; 18, helium channel; 19, coolant channel; 20, adsorption electrode channel; 21, heating electrode channel; 22, heating circuit; 23, adsorption electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] For the convenience of those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments does not limit the present invention.

[0037] As Figures 1-6 shown, in an embodiment of the present invention, a high-dielectric and high-breakdown-strength electrostatic chuck includes a ceramic dielectric layer, a bonding layer, and a metal base 11 arranged in sequence from top to bottom.

[0038] In one embodiment of the present invention, the ceramic dielectric layer includes a first ceramic dielectric layer 12, an adsorption electrode layer 15, a second ceramic dielectric layer 13, a heating layer 16, and a third ceramic dielectric layer 14 arranged in sequence from top to bottom. The third ceramic dielectric layer 14 is disposed on the upper end surface of the metal base 11. The electrostatic chuck is further provided with a plurality of helium pores 17 distributed at intervals, and the helium pores 17 penetrate through the lower surface and the upper surface of the ceramic dielectric layer from bottom to top. The upper surface of the first ceramic dielectric layer 13 is provided with a plurality of upwardly protruding and spaced-apart protrusions to provide support for the wafer and a flow passage for helium gas 18. The helium pores 17 penetrate upward through the third ceramic dielectric layer 14, the heating layer 16, the second ceramic dielectric layer 13, the adsorption electrode layer 15, and the first ceramic dielectric layer 12 in the metal base in sequence.

[0039] Furthermore, the metal base 11 is provided with a coolant channel 19 and a helium gas channel 18 communicating with a plurality of helium pores 17, and the helium gas channel 18 is annular. The adsorption electrode layer 15 and the heating layer 16 are respectively provided with an adsorption electrode lead-out end and a heating electrode lead-out end, and both the adsorption electrode lead-out end and the heating electrode lead-out end extend downward to the lower end of the metal base 11. The metal base 11 is provided with an adsorption electrode channel 20 for the adsorption electrode lead-out end to pass through and a heating electrode channel 21 for the heating electrode lead-out end to pass through. The coolant channel 19 can be arranged in a one-in-one-out spiral layout and a multi-in-multi-out dispersed array layout; that is, it is arranged in a spiral layout with one inlet and one outlet and a dispersed array layout with multiple outlets and multiple inlets. The material of the metal base 11 is stainless steel or aluminum.

[0040] In some embodiments of the present invention, the ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of alumina, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate.

[0041] In some embodiments of the present invention, the ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of aluminum nitride, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate.

[0042] In some embodiments of the present invention, the ceramic dielectric layer further includes 3 - 7 parts of a sintering aid.

[0043] In some embodiments of the present invention, the bonding layer is an organic bonding layer, and the material of the organic bonding layer is at least one of thermal conductive silicone and epoxy resin. The thermal conductive silicone and epoxy resin adopt materials in the prior art and are used to bond the ceramic dielectric layer and the metal base 11.

[0044] In an embodiment of the present invention, a method for preparing an electrostatic chuck with high dielectric constant and high breakdown strength includes the following steps: bonding a ceramic dielectric layer and a metal base 11 through an adhesive layer to form an electrostatic chuck.

[0045] In some embodiments of the present invention, the method for preparing the ceramic dielectric layer includes the following steps:

[0046] (1) Preparation of slurry: According to the raw material composition of the ceramic dielectric layer, take alumina or aluminum nitride and at least one of barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate, and mix them in proportion to obtain a mixed powder; then, by weight, put 90 - 161 parts of the mixed powder, 3 - 7 parts of a sintering aid, 45 - 55 parts of a solvent, and 0.5 - 2.5 parts of a dispersant into a ball mill equipped with 200 - 300 parts of alumina balls and perform ball milling at a speed of 40 - 70 r / min for 12 - 24 hours; then add 7 - 11 parts of a binder and 4 - 8 parts of a plasticizer to the ball mill and continue ball milling for 12 - 24 hours; then defoam the ball-milled slurry for 1 - 2 hours to obtain a casting slurry with a viscosity of 5000 - 10000 mPa·s; the purities of the alumina, aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are 99.9%, and the particle size is 0.2 - 3μm;

[0047] (2) Casting and cutting: Cast the defoamed casting slurry using a casting machine to obtain a green ceramic tape with a thickness of 0.3 - 0.6 mm, and cut it into green ceramic chips of the same size using a cutting machine;

[0048] (3) Drilling: Use a laser drilling machine or a mechanical drilling machine to process structural holes and positioning hole structures on the green ceramic chips;

[0049] (4) Printing and filling holes: Use a printing and filling machine to perform printing and filling operations of metal slurry on the surface of the drilled green ceramic chips. The main components of the metal slurry include tungsten, molybdenum, and their alloys, and the main function is to provide a conductive path and heat generation; the metal slurry can be tungsten, molybdenum, and their alloys in the prior art;

[0050] (5) Stacking: Stack the printed green ceramic chips, then place them on a rigid backing plate, put them into a plastic bag for vacuum packaging, and then put the packaged stacked chips into an isostatic press and press them at 60 - 80°C and 10 - 40 MPa for 10 - 30 minutes to obtain a green ceramic plate;

[0051] (6) Debinding: Place the green ceramic plate on a corundum-mullite bearing plate, put it into an atmosphere resistance furnace, and slowly heat it to 450 - 650°C at a heating rate of 0.3 - 1°C per minute and keep it warm for 3 - 6 hours to obtain a ceramic debound film;

[0052] (7) Sintering: subjecting the ceramic film for row arrangement to high-temperature sintering to obtain a sintered ceramic plate;

[0053] (8) Machining: subjecting the sintered ceramic plate to final machining through double-sided grinding and machining equipment to obtain a ceramic dielectric layer with a flatness < 5 μm and a surface roughness < 0.1 μm.

[0054] In some embodiments of the present invention, in step (1), alumina, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of SiO2, CaO, and MgO; in step (7), the ceramic film for row arrangement is loaded into a high-temperature sintering furnace and sintered at 1500 - 1650 °C for 2 - 4 hours to obtain a sintered ceramic plate.

[0055] Further, in step (1), aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of CeO2, CaO, CaF2, and Y2O3; in step (7), the ceramic film for row arrangement is loaded into a high-temperature sintering furnace and sintered at 1750 - 1850 °C for 2 - 4 hours to obtain a sintered ceramic plate.

[0056] Further, in step (1), the solvent is one or more of ethanol, ethyl acetate, isopropyl alcohol, n-butanol, and methyl ethyl ketone; the dispersant is at least one of castor oil, linseed oil, polyethylene glycol, and phosphate ester; the binder is polyvinyl butyral; the plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate, and diisononyl phthalate.

[0057] Embodiment 1

[0058] As Figures 1-6 shown, in this embodiment, an electrostatic chuck with high dielectric constant and high breakdown strength includes a ceramic dielectric layer, a bonding layer, and a metal base 11 arranged in sequence from top to bottom; the ceramic dielectric layer includes a first ceramic dielectric layer 12, an adsorption electrode layer 15, a second ceramic dielectric layer 13, a heating layer 16, and a third ceramic dielectric layer 14 arranged in sequence from top to bottom, and the third ceramic dielectric layer 14 is disposed on the upper end surface of the metal base 11; the electrostatic chuck is further provided with a plurality of helium pores 17 distributed at intervals, and the helium pores 17 penetrate through the lower surface and the upper surface of the ceramic dielectric layer from bottom to top, and the upper surface of the first ceramic dielectric layer 13 is provided with a plurality of upwardly protruding and spaced-apart protrusions to provide support for the wafer and a helium gas channel 18 for circulation. The bonding layer is an organic bonding layer, and the material of the organic bonding layer is thermal conductive silicone. The material of the metal base 11 is stainless steel.

[0059] Further, the metal base 11 is provided with a coolant channel 19 and a helium channel 18 communicating with a plurality of helium holes 17, and the helium channel 18 is annular; the adsorption electrode layer 15 and the heating layer 16 are respectively provided with an adsorption electrode lead-out end and a heating electrode lead-out end, and both the adsorption electrode lead-out end and the heating electrode lead-out end extend downward to the lower end of the metal base 11; the metal base 11 is provided with an adsorption electrode channel 20 for the adsorption electrode lead-out end to pass through and a heating electrode channel 21 for the heating electrode lead-out end to pass through.

[0060] When the electrostatic chuck of this embodiment is in use, the helium channel 18 and the helium holes 17 form a helium delivery path, and external helium can enter the metal base 11 and the ceramic dielectric layer through the helium channel 18 and the helium holes 17, enabling the electrostatic chuck and the wafer to be cooled, better controlling the temperature of the wafer, and achieving uniform heat transfer during wafer processing, which is beneficial to maintaining the stability and quality of the wafer.

[0061] Further, the adsorption electrode layer 15 is provided with an adsorption electrode 23, and the adsorption electrode 23 is connected to the adsorption electrode lead-out end. The heating layer 16 is provided with a heating circuit 22, and the heating circuit 23 is connected to the heating electrode lead-out end. The coolant channel 19 is arranged inside the metal base 11 and below the helium channel 18. The coolant channel 19 has a repeatedly zigzag structure, and both ends of the coolant channel 19 are respectively provided with an inlet and an outlet. The coolant channel 19 of this embodiment is arranged in a one-in-one-out spiral layout. The coolant flows repeatedly and zigzag in the coolant channel 19, which can cooperate with the heating circuit 23 to control the temperature of the wafer.

[0062] Further, the plurality of helium holes 17 are arranged in an annular array and above the inner cavity of the helium channel 18. Helium can enter the plurality of uniformly distributed helium holes 17 from the helium channel 18, which helps to make the temperature distribution on the ceramic dielectric layer and the wafer surface uniform during wafer processing.

[0063] Further, the ceramic dielectric layer, namely the first ceramic dielectric layer 12, the second ceramic dielectric layer 13, and the third ceramic dielectric layer 14, all comprise the following raw materials in parts by weight: 85 parts of alumina, 15 parts of barium titanate, 23 parts of barium zirconate titanate, 20 parts of lead magnesium niobate, and 18 parts of barium strontium titanate.

[0064] This embodiment also provides a preparation method for an electrostatic chuck with high dielectric constant and high breakdown strength, comprising the following steps: bonding the ceramic dielectric layer and the metal base 11 through an adhesive layer to make an electrostatic chuck.

[0065] Further, the preparation method of the ceramic dielectric layer comprises the following steps:

[0066] (1) Preparation of slurry: According to the raw material composition of the ceramic dielectric layer, alumina (Al2O3), barium titanate (BaTiO3), barium zirconate titanate (BaZr 0.2 Ti 0.8 O3), lead magnesium niobate (MgNb4O 12 Pb), and barium strontium titanate (BaSr(TiO3)2) are taken and mixed in proportion to obtain a mixed powder; then, by weight, 161 parts of the mixed powder, 5 parts of a sintering aid, 50 parts of a solvent, and 1.5 parts of a dispersant are put into a ball mill equipped with 250 parts of alumina pellets and ball milled at a speed of 50 r / min for 18 hours; then 8 parts of a binder and 6 parts of a plasticizer are added to the ball mill and ball milling continues for 18 hours; then the ball milled slurry is defoamed for 1.5 hours to obtain a casting slurry with a viscosity of 5000 - 10000 mPa.s; the purities of the alumina, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are 99.9%, and the particle size is 0.2 - 3μm; the sintering aid is SiO2;

[0067] (2) Casting and cutting: The defoamed casting slurry is formed using a casting machine to obtain a green ceramic tape with a thickness of 0.5 mm, and then cut into green ceramic chips of the same size by a cutting machine;

[0068] (3) Drilling: Structural holes and positioning hole structures are machined on the green ceramic chips using a laser drilling machine;

[0069] (4) Printing and filling holes: Metal slurry printing and hole filling operations are performed on the surface of the drilled green ceramic chips using a printing and hole filling machine. The main components of the metal slurry include tungsten, molybdenum, and their alloys, and the main function is to provide a conductive path and heat generation;

[0070] (5) Laminating: The printed green ceramic chips are stacked, then placed on a rigid backing plate, put into a plastic bag for vacuum plastic sealing, and the plastic sealed stacked chips are placed in an isostatic press and pressed at 70°C and 30 MPa for 20 minutes to obtain a green ceramic plate;

[0071] (6) Debinding: The green ceramic plate is placed on a corundum - mullite support plate, loaded into an atmosphere resistance furnace, and slowly heated to 550°C at a heating rate of 0.6°C / minute and held for 5 hours to obtain a ceramic debound sheet;

[0072] (7) Sintering: The ceramic debound sheet is loaded into a high - temperature sintering furnace and sintered at 1600°C for 3 hours to obtain a sintered ceramic plate;

[0073] (8) Machining: The sintered ceramic plate is finally processed through double - sided grinding and machining equipment to obtain a ceramic dielectric layer with a flatness <5μm and a surface roughness <0.1μm.

[0074] Further, in step (1), the solvent is ethyl acetate; the dispersant is polyethylene glycol; the binder is polyvinyl butyral; the plasticizer is dioctyl phthalate.

[0075] In Examples 2-10 and Comparative Example 1 of the present invention, the composition and dosage ratio of the raw materials for preparing the ceramic dielectric layer are different from those in Example 1, and the rest are the same as those in Example 1.

[0076] In Examples 1-10 and Comparative Example 1, the parts by weight of the raw materials of the ceramic dielectric layer are shown in Table 1 below:

[0077]

[0078] The performance parameters of the ceramic dielectric layers in Examples 1-10 and Comparative Examples 1-2 are shown in Table 2 below:

[0079]

[0080] It can be seen from Examples 1-10 and Comparative Example 1 that Al2O 3、 BaTiO3, BaZr 0.2 Ti 0.8 O3, MgNb4O 12 Pb, BaSr(TiO3)2 formulation adjustment can improve the breakdown strength and dielectric constant of the ceramic dielectric layer, thereby improving its adsorption force. Example 1 exhibits relatively high breakdown strength, dielectric constant, and adsorption force, with a breakdown strength of 31 KV / mm, a dielectric constant of 101, and an adsorption force of 207 gf / cm². The main component of the ceramic dielectric layer in Comparative Example 1 is Al2O3, without adding BaTiO3, BaZr 0.2 Ti 0.8 O3, MgNb4O 12 Pb, BaSr(TiO3)2, showing relatively low breakdown strength, dielectric constant, and adsorption force, with a breakdown strength of 15 KV / mm, a dielectric constant of 9.8, and an adsorption force of 50 gf / cm². The ceramic dielectric layer material with a high dielectric constant can store charges better, increase the electric field strength, and have low dielectric loss, thereby providing a stronger adsorption force. The electrostatic chuck has a strong enough adsorption force to fix the low-conductivity material, preventing it from moving or falling off during the processing, thus ensuring the accuracy and quality of semiconductor manufacturing.

[0081] Example 11

[0082] In this example, the ceramic dielectric layers, namely the first ceramic dielectric layer 12, the second ceramic dielectric layer 13, and the third ceramic dielectric layer 14, all comprise the following parts by weight of raw materials: 80 parts of aluminum nitride, 17 parts of barium titanate, 25 parts of barium zirconate titanate, 20 parts of lead magnesium niobate, and 18 parts of barium strontium titanate.

[0083] Further, the preparation method of the ceramic dielectric layer includes the following steps:

[0084] (1) Preparation of the slurry: According to the raw material composition of the ceramic dielectric layer, take aluminum nitride (AlN), barium titanate (BaTiO3), barium zirconate titanate (BaZr 0.2 Ti 0.8 O3), lead magnesium niobate (MgNb4O 12 Pb), and barium strontium titanate (BaSr(TiO3)2), mix them in proportion to obtain a mixed powder; then, by weight, put 160 parts of the mixed powder, 6 parts of the sintering aid, 50 parts of the solvent, and 2 parts of the dispersant into a ball mill equipped with 250 parts of alumina pellets for ball milling, and process for 18 hours at a speed of 50 r / min; then add 9 parts of the binder and 7 parts of the plasticizer to the ball mill and continue ball milling for 18 hours; then defoam the ball-milled slurry for 1.5 hours to obtain a casting slurry with a viscosity of 5000 - 10000 mPa.s; the purities of the aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are 99.9%, and the particle size is 0.2 - 3 μm; the sintering aid is CeO2;

[0085] (2) Casting and cutting: Use a casting machine to form the defoamed casting slurry to obtain a green ceramic tape with a thickness of 0.5 mm, and cut it into green ceramic chips of the same size with a cutting machine;

[0086] (3) Drilling: Use a laser drilling machine to process structural holes and positioning hole structures on the green ceramic chips;

[0087] (4) Printing and filling holes: Use a printing and filling machine to perform printing and filling operations of the metal slurry on the surface of the drilled green ceramic chips. The main components of the metal slurry include tungsten, molybdenum, and their alloys, and the main function is to provide a conductive path and heat generation;

[0088] (5) Laminating: Stack the printed green ceramic chips, then place them on a rigid backing plate, put them into a plastic bag for vacuum plastic sealing, and then put the plastic-sealed stacked chips into an isostatic press and press them at 70 °C and 30 MPa for 25 minutes to obtain a green ceramic plate;

[0089] (6) Debinding: Place the green ceramic plate on a corundum-mullite bearing plate, put it into an atmosphere resistance furnace, and slowly heat it to 550 °C at a heating rate of 0.3 - 1 °C / minute, and keep it warm for 56 hours to obtain a ceramic debinding sheet;

[0090] (7) Sintering: Put the ceramic debinding sheet into a high-temperature sintering furnace and sinter it at 1800 °C for 3 hours to obtain a sintered ceramic plate;

[0091] (8) Machining: The sintered ceramic plate is finally processed through double-sided grinding and machining equipment to obtain a ceramic dielectric layer with a flatness <5 μm and a surface roughness <0.1 μm.

[0092] The remaining content of Example 11 is the same as that of Example 1.

[0093] In Examples 12 - 20 of the present invention and Comparative Example 2, the composition and dosage ratio of the raw materials for preparing the ceramic dielectric layer are different from those of Example 11, and the remaining content is the same as that of Example 11.

[0094] In Examples 11 - 20 and Comparative Example 2, the parts by weight of the raw materials of the ceramic dielectric layer are shown in Table 3 below:

[0095]

[0096] The performance parameters of the ceramic dielectric layers in Examples 11 - 20 and Comparative Example 2 are shown in Table 4 below:

[0097]

[0098] It can be seen from Examples 11 - 20 and Comparative Example 2 that AlN 、 BaTiO3, BaZr 0.2 Ti 0.8 O3, MgNb4O 12 Pb, BaSr(TiO3)2 formula adjustment can improve the breakdown strength and dielectric constant of the ceramic dielectric layer, thereby improving its adsorption force. Example 11 shows relatively high breakdown strength, dielectric constant, and adsorption force. Its breakdown strength is 32 KV / mm, the dielectric constant is 103, and the adsorption force is 209 gf / cm². The main body of the ceramic formula in Comparative Example 2 is AlN, without adding BaTiO3, BaZr 0.2 Ti 0.8 O3, MgNb4O 12 Pb, BaSr(TiO3)2, showing relatively low breakdown strength, dielectric constant, and adsorption force. Its breakdown strength is 16 KV / mm, the dielectric constant is 8.6, and the adsorption force is 50 gf / cm². Thus, it can be concluded that adding BaTiO3, BaZr 0.2 Ti 0.8 O3, MgNb4O 12 Pb, BaSr(TiO3)2 to the ceramic can improve its breakdown strength, dielectric constant, and adsorption force. Ceramics with a high dielectric constant can store charges better, increase the electric field strength, and have low dielectric loss, thereby providing a stronger adsorption force. The electrostatic chuck has a strong enough adsorption force to fix low-conductivity materials, preventing them from moving or falling off during the processing, thereby ensuring the accuracy and quality of semiconductor manufacturing.

[0099] The electrostatic chuck of the present invention utilizes electrostatic adsorption technology to achieve efficient electrostatic adsorption through a high dielectric constant material. The high dielectric constant material can effectively store charges, thereby enhancing the electrostatic adsorption force and enabling workpieces such as wafers to maintain better stability and precision during the processing. In addition, the characteristic of high breakdown strength ensures the safety of the electrostatic chuck when operating in a high-voltage environment. During the semiconductor manufacturing process, it is often necessary to use a high-voltage power supply to control the temperature and position of the wafer. The electrostatic chuck with high breakdown strength can withstand higher voltages without breakdown, thus ensuring the stability and safety of the processing process.

[0100] The above specific embodiments further illustrate the technical solutions and beneficial effects of the present invention, rather than limiting the implementation manners. For those skilled in the art, any obvious replacements made without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. An electrostatic chuck with high dielectric constant and high breakdown strength, characterized in that: It includes a ceramic dielectric layer, a bonding layer, and a metal base disposed in sequence from top to bottom. The ceramic dielectric layer includes at least one ceramic dielectric layer. The raw materials of the ceramic dielectric layer include at least one of alumina and aluminum nitride, and include at least one of barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate. The ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of alumina, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate. The ceramic dielectric layer includes the following raw materials in parts by weight: 50 - 90 parts of aluminum nitride, 5 - 25 parts of barium titanate, 5 - 25 parts of barium zirconate titanate, 5 - 20 parts of lead magnesium niobate, and 2 - 20 parts of barium strontium titanate. The ceramic dielectric layer includes a first ceramic dielectric layer, an adsorption electrode layer, a second ceramic dielectric layer, a heating layer, and a third ceramic dielectric layer disposed in sequence from top to bottom. The third ceramic dielectric layer is disposed on the upper end surface of the metal base. The electrostatic chuck is also provided with a plurality of helium holes, and the helium holes penetrate through the lower surface and the upper surface of the ceramic dielectric layer from bottom to top. The upper surface of the first ceramic dielectric layer is provided with a plurality of convex portions protruding upward. The metal base is provided with a coolant channel and a helium channel communicating with the plurality of helium holes. The helium channel is annular. The adsorption electrode layer and the heating layer are respectively provided with an adsorption electrode lead-out end and a heating electrode lead-out end. The adsorption electrode lead-out end and the heating electrode lead-out end both extend downward to the lower end of the metal base. The metal base is provided with an adsorption electrode channel for the adsorption electrode lead-out end to pass through and a heating electrode channel for the heating electrode lead-out end to pass through.

2. A method for preparing an electrostatic chuck with high dielectric constant and high breakdown strength according to any one of claim 1, characterized in that It includes the following steps: bonding the ceramic dielectric layer and the metal base through the bonding layer to make an electrostatic chuck.

3. The preparation method of the electrostatic chuck with high dielectric constant and high breakdown strength according to claim 2, characterized in that: The preparation method of the ceramic dielectric layer includes the following steps: (1) Preparation of slurry: According to the raw material composition of the ceramic dielectric layer, take alumina or aluminum nitride and take at least one of barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate, and mix them in proportion to obtain a mixed powder. Then, by weight, put 90 - 161 parts of the mixed powder, 3 - 7 parts of a sintering aid, 45 - 55 parts of a solvent, and 0.5 - 2.5 parts of a dispersant into a ball mill for ball milling. Then add 7 - 11 parts of a binder and 4 - 8 parts of a plasticizer, and continue ball milling. Then defoam the ball-milled slurry to obtain a casting slurry. (2) Casting and cutting: Use a casting machine to form the defoamed casting slurry to obtain a ceramic green tape, and cut it into multiple ceramic green sheets. (3) Drilling: Process structural holes and positioning hole structures on the ceramic green sheet. (4) Printing and filling holes: Use a printing and hole-filling machine to perform printing and hole-filling operations of metal slurry on the surface of the drilled ceramic green sheet. (5) Stacking: Stack the printed ceramic green sheets and then perform plastic sealing. Then press the plastic-sealed stacked sheets to obtain a ceramic green board. (6) Debinding: Heat up the ceramic green board to perform debinding to obtain a ceramic debound sheet. (7) Sintering: Perform high-temperature sintering on the ceramic debound sheet to obtain a sintered ceramic board. (8) Machining: The sintered ceramic plate is machined to obtain a ceramic dielectric layer.

4. The preparation method of the electrostatic chuck with high dielectric constant and high breakdown strength according to claim 3, characterized in that: In step (1), alumina, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of SiO2, CaO, and MgO.

5. The preparation method of the electrostatic chuck with high dielectric constant and high breakdown strength according to claim 3, characterized in that: In step (1), aluminum nitride, barium titanate, barium zirconate titanate, lead magnesium niobate, and barium strontium titanate are taken and mixed in proportion to obtain a mixed powder; the sintering aid is at least one of CeO2, CaO, CaF2, and Y2O3.

6. The preparation method of the electrostatic chuck with high dielectric constant and high breakdown strength according to claim 3, characterized in that: In step (1), the dispersant is at least one of castor oil, coffee fish oil, polyethylene glycol, and phosphate ester; the plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate, and diisononyl phthalate.

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