Electrostatic chuck ceramic adsorption layer, preparation method thereof and electrostatic chuck

Abstract

The invention relates to the technical field of semiconductors, in particular to an electrostatic chuck ceramic adsorption layer, a preparation method thereof and an electrostatic chuck. The preparation method of the electrostatic chuck ceramic adsorption layer provided by the invention comprises the following steps: preparing ceramic slurry; casting the ceramic slurry to form a casting sheet; electrode slurry is printed on the casting sheet; drying to enable the electrode slurry to form a raw electrode; filling gap green ceramic chips or ceramic slurry in gaps between the green electrodes; the method comprises the following steps of: aligning and stacking a cast sheet which is provided with green electrodes and is filled with gap green ceramic sheets or ceramic slurry in gaps between the green electrodes and a cast sheet without the green electrodes, forming a green ceramic composite body through a vacuum hot pressing process, and degreasing and sintering the green ceramic composite body. The preparation method of the electrostatic chuck ceramic adsorption layer provided by the invention solves the technical problem that holes are easily formed in the edge of the electrode in the ceramic adsorption layer in the traditional process, and can prepare a ceramic body with a compact internal structure and without holes, thereby greatly improving the dielectric strength and air tightness of the product.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an electrostatic chuck ceramic adsorption layer, its preparation method, and the electrostatic chuck itself. Background Technology

[0002] Electrostatic chucks (ESCs) are key components in semiconductor equipment manufacturing, widely used in various processes such as thin film deposition, etching, ion implantation, EUV lithography, and vacuum bonding. Their main function is to use electrostatic attraction to clamp and fix wafers, while simultaneously providing precise temperature control.

[0003] A typical electrostatic chuck usually consists of an adsorption section for wafer adhesion, an insulation section for insulation, a heater for heating, and a base for support and temperature regulation. The adsorption section is the core component for wafer adhesion, and it contains embedded electrostatic electrodes. When a DC voltage is applied to the electrodes, the dielectric material of the adsorption section becomes polarized, generating an electrostatic force (usually Coulomb force or Johnson-Labec force) that firmly adheres the wafer to the chuck surface. Common materials for the adsorption section include polymers such as polyimide (PI), and ceramics or composite ceramics such as alumina, aluminum nitride, yttrium oxide, silicon carbide, and boron nitride.

[0004] In the manufacturing process of ceramic electrostatic chucks, a commonly used method for preparing the adsorption section is the casting-lamination process. This process typically includes the following steps: First, ceramic powder raw materials are prepared into a slurry; then, the slurry is cast into a uniform ceramic film (i.e., a green ceramic casting sheet) using a casting process; next, the casting sheet is cut and perforated; then, metal paste is printed onto the surface of the casting sheet to form an electrode pattern using methods such as screen printing; finally, the casting sheet with electrodes and the casting sheet without electrodes are stacked together, and a green ceramic composite with embedded electrodes is formed through a lamination process, which is then sintered to form the final ceramic adsorption layer.

[0005] However, this preparation process in the prior art has the following drawbacks: (1) When a cast sheet with electrodes is laminated with other cast sheets, the side area of ​​the electrodes is prone to a loose structure with the cast sheet, resulting in voids or defects. For example Figure 1 and Figure 2As shown, the laminated green ceramic composite includes an upper casting sheet 100', a green electrode 110', and a lower casting sheet 120'. A hole 105' is formed between the side region of the green electrode 110' and the casting sheet. Although these holes will shrink to a certain extent during the subsequent high-temperature sintering process, they will still remain in the final ceramic body, which will have an adverse effect on the adsorption uniformity, airtightness, and dielectric properties of the electrostatic chuck, thereby affecting the final performance and reliability of the product.

[0006] (2) Traditional lamination processes, such as warm isostatic pressing (WIP) to press multiple green ceramic sheets together, are prone to deformation of pre-formed holes (such as gas channel holes, ejector pin holes, etc.) on the cast sheet due to the isotropic nature of pressure transmission. This results in a decrease in the size and positional accuracy of the holes, which cannot meet the stringent requirements of high-end semiconductor equipment for component precision.

[0007] Therefore, how to solve the problems of easy formation of holes around the electrodes during the manufacturing process of ceramic electrostatic chucks and the deformation of holes (especially holes <0.5mm) and decrease in accuracy during the lamination process are technical problems that urgently need to be solved in this field. Summary of the Invention

[0008] This invention provides a ceramic adsorption layer for an electrostatic chuck, a method for preparing the same, and an electrostatic chuck, to solve the problems of easy formation of holes around the electrodes and easy deformation of holes and decrease in accuracy during the lamination process in the manufacture of ceramic electrostatic chucks.

[0009] According to a first aspect of the present invention, the present invention provides a method for preparing a ceramic adsorption layer for an electrostatic chuck, comprising the following steps: (1) Preparation of ceramic slurry; (2) The prepared ceramic slurry is cast to form a first casting sheet and a second casting sheet; electrode slurry is printed on the first casting sheet; the first casting sheet after printing the electrode slurry is dried so that the electrode slurry forms a green electrode; the gap between the green electrodes is filled with a gap green ceramic sheet or the ceramic slurry of the same thickness as the green electrode; wherein the material of the gap green ceramic sheet is the same as the material of the first casting sheet or the second casting sheet; (3) The first casting sheet with the green electrode and the gap between the green electrodes filled with the green ceramic sheet or the ceramic slurry is stacked with the second casting sheet and formed into a green ceramic composite by vacuum hot pressing; the green ceramic composite is degreased and sintered to obtain an electrostatic chuck ceramic adsorption layer.

[0010] The preparation method of this invention involves pre-filling the gaps between the green electrodes with a gap-forming ceramic sheet or ceramic slurry of the same material and thickness as the cast sheet before lamination and hot pressing, ensuring the density and uniformity of the overall structure before lamination. Combined with a vacuum hot pressing process, this avoids the porosity problem caused by uneven pressure in traditional isostatic pressing, ultimately producing a ceramic adsorption layer with a dense internal structure, no pores, high interfacial bonding strength, and uniform performance, significantly improving the dielectric properties, airtightness, and overall reliability of the electrostatic chuck.

[0011] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, in step (2), the gap width between the live electrodes is 1-4 mm and the height is 10-50 μm. This optimized design can enhance and balance the adsorption force of the electrostatic chuck on the wafer, ensuring that the wafer is firmly and flatly fixed during processing.

[0012] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, in step (2), the first casting sheet and the second casting sheet are each independently cut and punched before electrode paste is printed on the first casting sheet.

[0013] The present invention first cuts and punches the cast film, and then prints the electrodes. This can effectively avoid deformation or damage to precision holes (such as air holes and pin holes) caused by post-printing processing.

[0014] Preferably, the diameter of the holes formed on the first casting sheet and the second casting sheet is independently 0.1-8 mm, and the dimensional accuracy of the holes is independently ±0.01 mm; preferably, the holes include air holes, pin holes and electrode holes.

[0015] The present invention provides specific limits on aperture and aperture precision, ensuring that the final product can meet the extremely high geometric precision requirements of semiconductor equipment for components, thereby guaranteeing the accurate assembly of the chuck in the equipment and the reliable realization of functions such as gas transport and wafer lifting.

[0016] Preferably, the thickness of the first cast sheet and the second cast sheet are each independently 300-1200 μm.

[0017] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, in step (1), the ceramic slurry includes ceramic material, binder, dispersant and organic solvent; wherein, the solid content of the ceramic slurry is 40-60%; based on the weight of the ceramic material, the amount of binder is 2-10% and the amount of dispersant is 0.5-2%; the weight ratio of the ceramic material to the organic solvent is 1:(0.6-1.5).

[0018] This invention optimizes the composition and dosage of the ceramic slurry, ensuring the quality of the green ceramic sheets from the source. Controlling the solid content of the ceramic slurry to 40-60 wt% yields optimal rheological properties (such as viscosity and flowability), making it highly suitable for tape casting processes. This ensures that the prepared green ceramic tapes have excellent uniformity and density with few defects, providing a high-quality matrix material for all subsequent processes and forming the basis for obtaining high-performance ceramic adsorption layers.

[0019] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, the ceramic material is selected from one or more of alumina, aluminum nitride, silicon nitride, silicon carbide, boron nitride, zirconium oxide, titanium oxide, magnesium oxide, spinel and yttrium aluminum garnet.

[0020] Preferably, the ceramic material comprises aluminum nitride and silicon carbide, wherein the silicon carbide content is 5-25 wt% and the particle size of the silicon carbide is 20-200 nm; the aluminum nitride is prepared by direct nitriding or high-temperature carbothermal reduction and has a D50 of 0.5-1.5 μm.

[0021] This invention employs a specific aluminum nitride (AlN) matrix to ensure the chuck possesses high thermal conductivity, enabling precise temperature control of the wafer. Simultaneously, by doping with silicon carbide (SiC) particles of a specific content (5-25 wt%) and particle size, the volume resistivity of the ceramic body can be precisely adjusted to achieve the optimal range for generating the Johnson-Labec effect, thereby obtaining a strong and responsive electrostatic adsorption force. This material combination gives the electrostatic chuck both excellent temperature uniformity and strong adsorption performance.

[0022] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, in step (3), the vacuum hot pressing process is carried out by vertical pressure in the Z-axis direction, and the hot pressing temperature is 100-300℃, the vacuum degree is <1Kpa, and the pressure is 3-100 tons.

[0023] This invention employs a vertical pressure application method along the Z-axis, concentrating the pressure on the thickness of the laminate and effectively preventing lateral (radial) compression of the holes. This perfectly maintains the shape and positional accuracy of various precision holes on the cast sheet. The defined temperature, vacuum, and pressure ranges ensure a dense and robust interfacial bond between the layers without deformation, resulting in a high-flatness, high-density green ceramic composite.

[0024] According to the method for preparing the ceramic adsorption layer of the electrostatic chuck of the present invention, in step (3), the degreasing is performed in nitrogen at 500-700℃ for 1-3 hours; the sintering is performed in a mixed gas containing N2 and H2 at 1800-1900℃ for 2-10 hours.

[0025] This invention optimizes the process conditions for the two heat treatment steps of debinding and sintering, ensuring the successful transformation of green ceramic composites into high-performance dense ceramics. The staged heating process—first performing low-temperature debinding in nitrogen to gently remove organic matter, and then performing high-temperature sintering in a hydrogen-nitrogen mixed atmosphere—effectively prevents defects such as cracks and bubbles from occurring during the debinding and densification processes, thereby obtaining dense ceramic materials with the desired microstructure and excellent mechanical and electrical properties.

[0026] According to a second aspect of the present invention, the present invention also provides an electrostatic chuck ceramic adsorption layer, which is prepared by the above-described method for preparing an electrostatic chuck ceramic adsorption layer; the electrostatic chuck ceramic adsorption layer includes a dielectric layer, an electrode and an insulating layer, wherein the electrode is embedded between the dielectric layer and the insulating layer, and there are no holes in the side region of the electrode.

[0027] The ceramic adsorption layer of the electrostatic chuck prepared by the method of this invention has a unique internal structure, with no pores in the side regions of the electrodes. This dense and defect-free structure eliminates many drawbacks caused by pores at the electrode edges in traditional processes, such as localized electric field breakdown, gas leakage, and uneven heat conduction. Therefore, this ceramic adsorption layer has higher dielectric strength, better airtightness, and more uniform thermal conductivity, thereby significantly improving the overall reliability and service life of the electrostatic chuck.

[0028] According to the electrostatic chuck ceramic adsorption layer of the present invention, the electrodes can be single electrodes, dual electrodes, six electrodes, or more. The electrode materials can be W, Mo, WMo, WC, Mo2C, Pt, Ru, Pd, etc.

[0029] According to the electrostatic chuck ceramic adsorption layer of the present invention, the resistivity of the electrostatic chuck ceramic adsorption layer is 2*E. 10 -5*E 12 Ω·cm, thermal conductivity 35-100W / mk.

[0030] According to a third aspect of the present invention, the present invention also provides an electrostatic chuck, comprising an electrostatic chuck ceramic adsorption layer prepared by the above-described method for preparing an electrostatic chuck ceramic adsorption layer or the above-described electrostatic chuck ceramic adsorption layer.

[0031] The beneficial effects of this invention are: The method for preparing the ceramic adsorption layer of the electrostatic chuck provided by this invention pre-fills the electrode gaps before stacking and combines this with a vacuum hot pressing process. This fundamentally solves the technical problem of easy formation of pores at the electrode edges inside the ceramic adsorption layer in traditional processes. It can produce a ceramic body with a completely dense internal structure and no pores, thereby greatly improving the dielectric strength and airtightness of the product and avoiding the risk of electrical breakdown and gas leakage caused by defects. At the same time, the method for preparing the ceramic adsorption layer of the electrostatic chuck provided by this invention also ensures the high geometric accuracy of the product, so that the prepared electrostatic chuck has higher operational reliability, better overall performance and longer service life, and can meet the stringent requirements of advanced semiconductor processes. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the laminated green ceramic composite provided for the background technology of this invention.

[0034] Figure 2 for Figure 1 Enlarged view of point I.

[0035] Figure 3 This is a schematic diagram of the structure of the ceramic adsorption layer of the electrostatic chuck provided in Embodiment 1 of the present invention.

[0036] Figure 4 This is an exploded view of the green ceramic composite provided in Embodiment 1 of the present invention before lamination.

[0037] Figure 5 This is a schematic diagram of the structure of the green ceramic composite provided in Embodiment 1 of the present invention.

[0038] Figure 6 This is one of the structural schematic diagrams of the green ceramic composite provided in Embodiment 3 of the present invention.

[0039] Figure 7 This is one of the structural schematic diagrams of the green ceramic composite provided in Embodiment 4 of the present invention.

[0040] Figure 8 This is one of the structural schematic diagrams of the green ceramic composite provided in Embodiment 6 of the present invention.

[0041] Figure 9 This is one of the structural schematic diagrams of the green ceramic composite provided in Embodiment 7 of the present invention.

[0042] Reference numerals: 1: Electrostatic chuck ceramic adsorption layer; 10: Dielectric layer; 11: Electrode; 12: Insulating layer; 100', 100: Upper casting sheet; 110', 110: Green electrode; 120', 120: Lower casting sheet; 115: Gap green ceramic sheet; 105': Hole. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] Example 1 This embodiment provides a ceramic adsorption layer for an electrostatic chuck, such as... Figure 3 As shown, the ceramic adsorption layer 1 of the electrostatic chuck includes a dielectric layer 10, an electrode 11, and an insulating layer 12. There are no holes in the side region of the electrode 11. The electrode 11 is a tungsten electrode.

[0045] This embodiment also provides a method for preparing the ceramic adsorption layer of the electrostatic chuck, including the following steps: (1) 10,000 g of aluminum nitride powder with a D50 of 0.8 μm prepared by direct nitriding or high-temperature carbothermal reduction, 500 g of silicon carbide particles with a particle size of 100 nm, 800 g of binder (polymethyl methacrylate), 100 g of dispersant (BYK Chemical BK-111), and 11,400 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 5 wt%.

[0046] (2) For example Figure 4 As shown, the ceramic slurry is processed by a casting machine to form an upper casting sheet 100 with a thickness of 300 μm, a lower casting sheet 120 with a thickness of 300 μm, and a gap green ceramic sheet 115 with a thickness of 10 μm, which are then cut into 450*450 mm casting sheets. An electrode slurry (composed of tungsten slurry) with a thickness of 10 μm is printed on the lower casting sheet 120. The lower casting sheet 120 after printing the electrode slurry is dried so that the electrode slurry forms a green electrode 110. The aforementioned 10 μm gap green ceramic sheet 115 is cut into a gap shape according to the size of the gap of the green electrode 110 and filled in the gap of the green electrode 110.

[0047] (3) such as Figure 5As shown, the lower casting sheet 120 with green electrode 110 and gap green ceramic sheet 115 is aligned and stacked with the upper casting sheet 100 to form a whole. This whole is placed in a vacuum hot press, with the vacuum degree controlled at <1 kPa, pressure at 3 t, pressure held for 20 min, and temperature at 150℃. Pressure is applied along the Z-axis to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2 h. Then, it is sintered at 1800℃ for 8 h in a mixed atmosphere of hydrogen and nitrogen to form the electrostatic chuck ceramic adsorption layer 1.

[0048] 5*E of aluminum nitride ceramics was measured using a high resistance meter. 12 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 100 W / mk (Ω·cm).

[0049] Example 2 This embodiment provides an electrostatic chuck ceramic adsorption layer, the structure of which is the same as that in Embodiment 1.

[0050] The only difference between the preparation method of the electrostatic chuck ceramic adsorption layer and Example 1 is that in step (2), screen printing is used to print the ceramic paste on the gap of the live electrode 110, and after drying, a gap live ceramic sheet 115 with a thickness of 10 μm is formed.

[0051] The 4.5*E of aluminum nitride ceramics was measured using a high resistivity meter. 12 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 90 W / mk (Ω·cm).

[0052] Example 3 This embodiment provides an electrostatic chuck ceramic adsorption layer 1, which includes a dielectric layer 10, an electrode 11, and an insulating layer 12. The side region of the electrode 11 has no holes. The electrode 11 is a single electrode.

[0053] This embodiment also provides a method for preparing the ceramic adsorption layer of the electrostatic chuck. The difference between this method and that of Embodiment 1 is that in step (2), the cast sheet is punched to form pores with a size of 0.5 mm, pin holes with a size of 6 mm, and electrode holes with a size of 3 mm. Figure 6 As shown.

[0054] 5*E of aluminum nitride ceramics was measured using a high resistance meter. 12 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 95 W / mk (Ω·cm).

[0055] Example 4 This embodiment provides an electrostatic chuck ceramic adsorption layer 1, which includes a dielectric layer 10, an electrode 11, and an insulating layer 12. The side region of the electrode 11 has no holes. The electrode 11 is a tungsten-molybdenum dual electrode.

[0056] This embodiment also provides an electrostatic chuck ceramic adsorption layer, which includes the following steps: (1) 10,000 g of aluminum nitride powder with a D50 of 0.8 μm prepared by direct nitriding or high-temperature carbothermal reduction, 1,000 g of silicon carbide particles with a particle size of 100 nm, 800 g of binder (polymethyl methacrylate), 100 g of dispersant (BYK Chemical BK-111), and 11,900 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 10 wt%.

[0057] (2) The ceramic slurry is used to form an upper casting sheet 100 with a thickness of 500 μm, a lower casting sheet 120 with a thickness of 500 μm, and a gap green ceramic sheet 115 with a thickness of 30 μm, respectively, and then cut into casting sheets of 450*450 mm. The casting sheets are punched to form pores with a size of 0.5 mm, pin holes with a size of 6 mm, and electrode holes with a size of 3 mm. An electrode slurry (composed of tungsten-molybdenum slurry) with a thickness of 30 μm is printed on the lower casting sheet 120. The lower casting sheet 120 after printing the electrode slurry is dried so that the electrode slurry forms a green electrode 110. The green electrode 110 is a double electrode with a thickness of 30 μm, such as Figure 7 As shown, the 10μm gap green ceramic sheet 115 is cut into a gap shape according to the size of the gap of the green electrode 110 and filled in the gap of the green electrode 110.

[0058] (3) The lower casting sheet 120 with green electrode 110 and gap green ceramic sheet 115 is aligned and stacked with the upper casting sheet 100 to form a whole. This whole is placed in a vacuum hot press with a vacuum degree <1Kpa, pressure 100t, pressure held for 20min, and temperature 100℃. Pressure is applied in the Z-axis direction to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2h. Then, it is sintered at 1820℃ for 10h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck adsorption layer 1.

[0059] 4*E of aluminum nitride ceramics was measured using a high resistance meter. 11 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 60 W / mk (Ω·cm).

[0060] Example 5 This embodiment provides an electrostatic chuck ceramic adsorption layer 1, which includes a dielectric layer 10, an electrode 11, and an insulating layer 12. The side region of the electrode 11 has no holes. The electrode 11 is a WC dual electrode.

[0061] This embodiment also provides an electrostatic chuck ceramic adsorption layer, which includes the following steps: (1) 10,000 g of aluminum nitride powder with a D50 of 1 μm prepared by direct nitriding or high-temperature carbothermal reduction, 2,000 g of silicon carbide particles with a particle size of 200 nm, 800 g of binder (polymethyl methacrylate), 80 g of dispersant (BYK Chemical BK-111), and 12,800 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 20 wt%.

[0062] (2) The ceramic slurry is cast into a 800μm thick cast sheet and a 40μm gap green ceramic sheet 115 using a casting machine, and then cut into 450*450mm cast sheets. The cast sheets are punched to form pores with a size of 0.5mm, pin holes with a size of 6mm, and electrode holes with a size of 3mm. Electrode slurry (composed of WC slurry) is printed on the lower cast sheet 120, such as... Figure 7 As shown. After the electrode paste is printed, the lower casting film 120 is dried to form a green electrode 110. The above-mentioned 40μm gap green ceramic sheet 115 is cut into a gap shape according to the size of the gap of the green electrode 110 and filled in the gap of the green electrode 110.

[0063] (3) The lower casting sheet 120 with green electrode 110 and gap green ceramic sheet 115 is aligned and stacked with the upper casting sheet 100 to form a whole. This whole is placed in a vacuum hot press with a vacuum degree <1Kpa, pressure 50t, pressure held for 20min, and temperature 180℃. Pressure is applied in the Z-axis direction to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2h. Then, it is sintered at 1850℃ for 6h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck adsorption layer 1.

[0064] 8*E of aluminum nitride ceramics was measured using a high resistance meter. 10 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 45 W / mk (Ω·cm).

[0065] Example 6 This embodiment provides an electrostatic chuck ceramic adsorption layer 1, which includes a dielectric layer 10, an electrode 11, and an insulating layer 12. The side region of the electrode 11 has no holes. The electrode 11 is a tungsten dual electrode.

[0066] This embodiment also provides an electrostatic chuck ceramic adsorption layer, which includes the following steps: (1) 10,000 g of aluminum nitride powder with a D50 of 1.2 μm prepared by direct nitriding or high-temperature carbothermal reduction, 2,500 g of silicon carbide particles with a particle size of 150 nm, 400 g of binder (PVB), 150 g of dispersant (BYK Chemical BK-111), and 13,050 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 25 wt%.

[0067] (2) The ceramic slurry is cast into a 1200μm thick cast sheet and a 50μm gap green ceramic sheet 115 using a casting machine. The cast sheet is then cut into 450*450mm cast sheets. The cast sheets are punched to form pores of 0.5mm, pin holes of 6mm, and electrode holes of 3mm. Electrode slurry (composed of tungsten slurry) is printed on the lower cast sheet 120. The lower cast sheet 120 after printing the electrode slurry is dried, allowing the electrode slurry to form a green electrode 110. The green electrode 110 is a dual electrode with a thickness of 50μm. Figure 8 As shown. After the lower casting film 120 with printed electrodes is dried, the above-mentioned 50μm gap green ceramic sheet 115 is cut into a gap shape according to the size of the gap of the green electrode 110 and filled in the gap of the green electrode 110.

[0068] (3) The lower casting sheet 120 with green electrode 110 and gap green ceramic sheet 115 is aligned and stacked with the upper casting sheet 100 to form a whole. This whole is placed in a vacuum hot press with a vacuum degree <1Kpa, pressure 75t, pressure held for 30min, and temperature 200℃. Pressure is applied in the Z-axis direction to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2h. Then, it is sintered at 1870℃ for 4h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck adsorption layer 1.

[0069] 2*E of aluminum nitride ceramics was measured using a high resistance meter. 10 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 35 W / mk (Ω·cm).

[0070] Example 7 This embodiment provides an electrostatic chuck ceramic adsorption layer 1, which includes a dielectric layer 10, an electrode 11, and an insulating layer 12. The side region of the electrode 11 has no holes. The electrode 11 is a Pt hex electrode.

[0071] This embodiment also provides an electrostatic chuck ceramic adsorption layer, which includes the following steps: (1) 10,000 g of aluminum nitride powder with a D50 of 1 μm prepared by direct nitriding or high-temperature carbothermal reduction, 1,500 g of silicon carbide particles with a particle size of 20 nm, 1,000 g of binder (PVB), 50 g of dispersant (BYK Chemical BK-111), and 12,550 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 15 wt%.

[0072] (2) The ceramic slurry is cast into a 600μm thick cast sheet and a 25μm thick interstitial green ceramic sheet 115 using a casting machine. The cast sheets are then cut into 450*450mm pieces. The cast sheets are punched to form pores of 0.5mm, pin holes of 6mm, and electrode holes of 3mm. Electrode slurry (composed of Pt slurry) is printed onto the lower cast sheet 120. The lower cast sheet 120 after printing the electrode slurry is dried, allowing the electrode slurry to form a green electrode 110, such as... Figure 9 As shown. After the lower casting film 120 with printed electrodes is dried, the above-mentioned 25μm gap green ceramic sheet 115 is cut into a gap shape according to the size of the gap of the green electrode 110 and filled in the gap of the green electrode 110.

[0073] (3) The lower casting sheet 120 with green electrode 110 and gap green ceramic sheet 115 is aligned and stacked with the upper casting sheet 100 to form a whole. This whole is placed in a vacuum hot press with a vacuum degree <1Kpa, pressure 3t, pressure held for 20min, and temperature 300℃. Pressure is applied in the Z-axis direction to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2h. Then, it is sintered at 1880℃ for 2h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck adsorption layer 1.

[0074] Detection of 1*E in aluminum nitride ceramics using a high resistance meter 11 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 42 W / mk (Ω·cm).

[0075] Comparative Example 1 (1) 10,000 g of aluminum nitride powder with a D50 of 0.8 μm prepared by direct nitriding or high-temperature carbothermal reduction, 500 g of silicon carbide particles with a particle size of 100 nm, 800 g of binder (polymethyl methacrylate), 100 g of dispersant (BYK Chemical BK-111), and 11,400 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 5 wt%.

[0076] (2) The ceramic slurry is used to make an upper casting sheet 100 with a thickness of 300 μm and a lower casting sheet 120 with a thickness of 300 μm, respectively, and then cut into casting sheets of 450*450 mm. An electrode slurry (composed of tungsten slurry) with a thickness of 10 μm is printed on the lower casting sheet 120. The lower casting sheet 120 after the electrode slurry is printed is dried so that the electrode slurry forms a green electrode 110.

[0077] (3) The green electrode 110 and the lower casting sheet 120 are aligned and superimposed with the upper casting sheet 100 to form a whole. The gaps between the green electrodes are not filled with casting sheets or ceramic slurry. The whole is placed in a vacuum hot press, and the vacuum degree is controlled to be <1 kPa, the pressure is 3t, the pressure is held for 20 min, and the temperature is 150℃. Pressure is applied in the Z-axis direction to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600℃ for 2 h. Then, it is sintered at 1800℃ for 8 h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck ceramic adsorption layer 1.

[0078] 4*E of aluminum nitride ceramics was measured using a high resistance meter. 12 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 90 W / mk (Ω·cm).

[0079] Comparative Example 2 (1) 10,000 g of aluminum nitride powder with a D50 of 0.8 μm prepared by direct nitriding or high-temperature carbothermal reduction, 500 g of silicon carbide particles with a particle size of 100 nm, 800 g of binder (polymethyl methacrylate), 100 g of dispersant (BYK Chemical BK-111), and 11,400 g of organic solvent (ethanol and toluene) were used to prepare a ceramic slurry with a solid content of 50%. The amount of silicon carbide added was 5 wt%.

[0080] (2) The ceramic slurry is used to make an upper casting sheet 100 with a thickness of 300 μm and a lower casting sheet 120 with a thickness of 300 μm, respectively, and then cut into casting sheets of 450*450 mm. An electrode slurry (composed of tungsten slurry) with a thickness of 10 μm is printed on the lower casting sheet 120. The lower casting sheet 120 after the electrode slurry is printed is dried so that the electrode slurry forms a green electrode 110.

[0081] (3) The green electrode 110 and the lower casting sheet 120 are aligned and superimposed with the upper casting sheet 100 to form a whole. The gaps between the green electrodes are not filled with casting sheets or ceramic slurry. The whole is placed in a warm isostatic press at a pressure of 50 MPa for 20 min and a temperature of 85°C. Isotropic pressure is applied to form a green ceramic composite. The green ceramic composite is degreased with nitrogen at 600°C for 2 h. Then, it is sintered at 1800°C for 8 h in a mixed atmosphere of hydrogen and nitrogen to form an electrostatic chuck ceramic adsorption layer 1.

[0082] 5*E of aluminum nitride ceramics was measured using a high resistance meter. 12 The thermal conductivity of aluminum nitride, measured using laser scintillation method, is 95 W / mk (Ω·cm).

[0083] The performance of the electrostatic chuck ceramic adsorption layer in the examples and comparative examples was tested using the following methods: The shape and position accuracy of the functional pores (pores, lift pin holes) of the ceramic adsorption layer of the electrostatic chuck were detected using 3D optical inspection equipment, and the micromorphology of the electrode edge was detected using scanning electron microscopy.

[0084] Experiments have shown that all embodiments 1-7 of the present invention meet the following requirements: the positional accuracy of the functional holes is ≤ ±0.02 mm, the roundness is ±0.01 mm, the flatness after sintering is ≤0.05 mm, the electrode edges are tightly bonded, and there are no obvious pores, thus meeting the performance requirements of the electrostatic chuck.

[0085] In the comparative example, the positional accuracy of the functional holes is ±0.05 mm, and the roundness is ±0.05 mm. After sintering, the flatness is ≤0.14 mm, and there are no microscopic defects in the electrode and ceramic cross-section.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a ceramic adsorption layer for an electrostatic chuck, characterized in that, Includes the following steps: (1) Preparation of ceramic slurry; (2) The prepared ceramic slurry is cast to form a first casting sheet and a second casting sheet; electrode slurry is printed on the first casting sheet; the first casting sheet after printing the electrode slurry is dried so that the electrode slurry forms a green electrode; the gap between the green electrodes is filled with a gap green ceramic sheet or the ceramic slurry of the same thickness as the green electrode; wherein the material of the gap green ceramic sheet is the same as the material of the first casting sheet or the second casting sheet; (3) The first casting sheet with the green electrode and the gap between the green electrodes filled with the green ceramic sheet or the ceramic slurry is stacked with the second casting sheet and formed into a green ceramic composite by vacuum hot pressing; the green ceramic composite is degreased and sintered to obtain an electrostatic chuck ceramic adsorption layer.

2. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to claim 1, characterized in that, In step (2), the gap width between the live electrodes is 1-4 mm and the height is 10-50 μm.

3. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to claim 1 or 2, characterized in that, In step (2), the first and second cast sheets are each independently cut and punched before electrode paste is printed on the first cast sheet; Preferably, the diameter of the holes formed on the first casting sheet and the second casting sheet is independently 0.1-8 mm, the roundness of the holes is ±0.01 mm, and the positional accuracy is ±0.02 mm; preferably, the holes include air holes, pin holes, and electrode holes; Preferably, the thickness of the first cast sheet and the second cast sheet are each independently 300-1200 μm.

4. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to any one of claims 1-3, characterized in that, In step (1), the ceramic slurry includes ceramic materials, binder, dispersant and organic solvent; wherein, the solid content of the ceramic slurry is 40-60%; based on the weight of the ceramic materials, the amount of binder is 2-10% and the amount of dispersant is 0.5-2%; the weight ratio of the ceramic materials to the organic solvent is 1:(0.6-1.5).

5. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to claim 4, characterized in that, The ceramic material is selected from one or more of alumina, aluminum nitride, silicon nitride, silicon carbide, boron nitride, zirconium oxide, titanium oxide, magnesium oxide, spinel, and yttrium aluminum garnet; Preferably, the ceramic material comprises aluminum nitride and silicon carbide, and the silicon carbide content is 5-25 wt% relative to the mass of the aluminum nitride, and the particle size of the silicon carbide is 20-200 nm; the aluminum nitride is prepared by direct nitriding or high-temperature carbothermal reduction, and the D50 is 0.5-1.5 μm.

6. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to any one of claims 1-5, characterized in that, In step (3), the vacuum hot pressing process is carried out by vertical pressure in the Z-axis direction, and the hot pressing temperature is 100-300℃, the vacuum degree is <1Kpa, and the pressure is 3-100 tons.

7. The method for preparing the ceramic adsorption layer of the electrostatic chuck according to any one of claims 1-6, characterized in that, In step (3), the degreasing is performed in nitrogen at 500-700℃ for 1-3 hours; the sintering is performed in a mixed gas containing N2 and H2 at 1800-1900℃ for 2-10 hours.

8. A ceramic adsorption layer for an electrostatic chuck, characterized in that, The electrostatic chuck ceramic adsorption layer is prepared by the preparation method of any one of claims 1-7; the electrostatic chuck ceramic adsorption layer includes a dielectric layer, an electrode and an insulating layer, the electrode is embedded between the dielectric layer and the insulating layer, and there are no holes in the side area of ​​the electrode.

9. The electrostatic chuck ceramic adsorption layer according to claim 8, characterized in that, The resistivity of the ceramic adsorption layer of the electrostatic chuck is 2*E. 10 -5*E 12 Ω·cm, thermal conductivity 35-100W / mk.

10. An electrostatic chuck, characterized in that, This includes the electrostatic chuck ceramic adsorption layer prepared by the method for preparing the electrostatic chuck ceramic adsorption layer according to any one of claims 1-7, or the electrostatic chuck ceramic adsorption layer according to claim 8 or 9.

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