Electrostatic chuck and method of making the same

Abstract

The present application relates to the technical field of semiconductor manufacturing, and provides an electrostatic chuck and a preparation method thereof, wherein the electrostatic chuck comprises a base, an electrode layer and a dielectric layer, the base is made of ceramic material; the electrode layer is arranged on the base surface; the dielectric layer is arranged on the outer surface of the electrode layer relative to the base, and the dielectric layer is formed by at least one of a spraying process and a deposition process. In this way, the base is made of non-metal material, and it is not necessary to arrange an insulating layer between the base and the electrode layer, and it is not necessary to arrange a bonding layer, so that the failure of the bonding layer can be avoided from the source. The dielectric layer is made of ceramic material, and the thermal expansion coefficients of the dielectric layer and the base are close, so that the problems of delamination and cracking caused by thermal stress due to the mismatch of the thermal expansion coefficients can be avoided.

Description

Technical Field

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

[0002] An electrostatic chuck (ESC) is a core component that uses electrostatic force to hold and hold wafers in place. It is widely used in semiconductor process equipment such as etching, chemical vapor deposition, and physical vapor deposition. As semiconductor technology nodes continue to shrink and wafer sizes continue to increase, the process environment is becoming increasingly demanding, placing higher requirements on the reliability, temperature uniformity, resistance to plasma erosion, and particulate contamination control of ESCs.

[0003] Currently, electrostatic chucks typically employ a composite structure of a metal base and a ceramic disk, bonded together using organic adhesive or solder. However, the thermal expansion coefficients of the metal base and the ceramic disk differ significantly. During the repeated high and low temperature thermal cycling in semiconductor processes, enormous thermal stress is generated at the interface between these dissimilar materials. This thermal stress can cause fatigue, aging, or even delamination failure of the adhesive layer between the metal base and the ceramic disk. Adhesive layer failure not only leads to a sharp increase in thermal resistance and deterioration of wafer temperature uniformity but may also trigger partial discharge or plasma arcing, ultimately causing the electrostatic chuck to malfunction.

[0004] Therefore, how to solve the problem of adhesive layer failure in electrostatic chucks has become an important technical problem for those skilled in the art. Summary of the Invention

[0005] This invention aims to solve the technical problems existing in related technologies. To this end, this invention proposes an electrostatic chuck to solve the problem of adhesive layer failure that easily occurs in electrostatic chucks in related technologies.

[0006] The present invention also proposes a method for preparing an electrostatic chuck.

[0007] An electrostatic chuck according to an embodiment of the present invention includes: The base is made of ceramic. An electrode layer is disposed on the base surface of the base; The dielectric layer is made of ceramic and covers the outer surface of the electrode layer relative to the substrate. The dielectric layer is formed by at least one of a spraying process and a deposition process.

[0008] According to one embodiment of the present invention, the base is made of at least one of alumina, aluminum nitride, glass ceramic, yttrium oxide, silicon carbide, zirconium oxide and yttrium aluminum garnet.

[0009] According to one embodiment of the present invention, the base is formed by hot pressing sintering or tape stacking sintering.

[0010] According to one embodiment of the present invention, the electrode layer is formed on the substrate by a deposition process or a printing process, and the electrode layer is made of metal or conductive ceramic.

[0011] According to one embodiment of the present invention, the dielectric layer comprises: A first dielectric layer is formed by a spraying process, covering the outer surface of the electrode layer relative to the base. A second dielectric layer is formed by a deposition process, covering the surface of the first dielectric layer on the side away from the substrate.

[0012] According to one embodiment of the present invention, the first dielectric layer is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium aluminate; The second dielectric layer is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium aluminate.

[0013] According to one embodiment of the present invention, the thickness of the first dielectric layer is 50 to 500 micrometers, and the thickness of the second dielectric layer is 20 to 200 micrometers.

[0014] According to one embodiment of the present invention, the porosity of the first dielectric layer is less than 8%, and the porosity of the second dielectric layer is less than 2%.

[0015] According to one embodiment of the present invention, the base is provided with a connection hole, a pin hole and an electrode terminal. The connection hole is used for connecting the base to the target component. The pin hole penetrates the base, the electrode layer and the dielectric layer. The electrode terminal penetrates the base and one end of the electrode terminal is in electrical contact with the electrode layer.

[0016] The method for preparing an electrostatic chuck according to an embodiment of the present invention is used to prepare an electrostatic chuck as described above, the method comprising: A ceramic base is prepared, and connection holes, pin holes, and electrode terminal holes are machined on the base; An electrode layer is prepared on the base surface of the substrate using a deposition or printing process; A first dielectric layer is prepared on the outer surface of the electrode layer using a spray coating process; A second dielectric layer is prepared on the surface of the first dielectric layer away from the substrate using a deposition process.

[0017] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: The electrostatic chuck in this embodiment of the invention has a ceramic base, with the electrode layer formed on the base surface. Since the base is non-metallic, there is no need for an insulating layer or adhesive layer between the base and the electrode layer, thus avoiding adhesive layer failure at the source. A dielectric layer covers the outer surface of the electrode layer relative to the base, and is formed by at least one of spraying and deposition processes. The dielectric layer is made of ceramic, and its coefficient of thermal expansion is close to that of the base, avoiding delamination and cracking of the adhesive layer caused by thermal stress due to mismatched coefficients of thermal expansion. This design solves the problem of adhesive layer failure in electrostatic chucks in related technologies, and helps extend the service life of the electrostatic chuck under harsh thermal cycling conditions.

[0018] Furthermore, the electrostatic chuck preparation method provided in this embodiment of the invention can prevent the electrostatic chuck from failing due to adhesive layer failure and can extend the service life of the electrostatic chuck under harsh thermal cycling conditions.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention and are not considered as limitations on this application. Moreover, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an electrostatic chuck provided by the present invention.

[0022] Figure 2 This is a schematic diagram of another electrostatic chuck provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the electrostatic chuck in control group two of this invention.

[0024] Figure 4 This is a flowchart of the preparation method of the electrostatic chuck provided by the present invention.

[0025] Figure label: 1. Base; 2. Electrode layer; 3. Dielectric layer; 31. First dielectric layer; 32. Second dielectric layer; 4. Connecting hole; 5. Pin hole; 6. Electrode terminal; 1'. Metal base; 2'. Electrode layer; 3'. Dielectric layer; 4'. Threaded hole; 5'. Pin hole; 6'. Electrode terminal; 7'. Insulating layer. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] The specific terms used in this specification are for illustrative purposes only and are not intended to limit the illustrative embodiments. For example, expressions such as "identical" and "the same" not only indicate a state of strict sameness, but also indicate a state of difference in tolerance or having the same degree of functionality.

[0028] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0029] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of those features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified. In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, B1 and / or B2 can represent: B1 existing alone, B1 and B2 existing simultaneously, and B2 existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The following is combined with Figures 1 to 4 The electrostatic chuck of the present invention is described.

[0032] Electrostatic chucks typically employ a composite structure of a metal base and a ceramic disk, bonded together using organic adhesive or solder. Due to the significant difference in thermal expansion coefficients between the metal base and the ceramic disk, substantial thermal stress is generated at the interface during the repeated high and low temperature cycles of semiconductor processing. This thermal stress can cause fatigue, aging, or even delamination failure of the adhesive layer between the metal base and the ceramic disk. Adhesive layer failure not only leads to a sharp increase in thermal resistance and deterioration of wafer temperature uniformity but may also trigger partial discharge or plasma arcing, ultimately causing the electrostatic chuck to malfunction.

[0033] Therefore, it is of great significance to develop an electrostatic chuck that can avoid adhesive layer failure.

[0034] like Figures 1 to 4 As shown, the electrostatic chuck provided in this embodiment of the invention includes a base 1, an electrode layer 2, and a dielectric layer 3.

[0035] Specifically, the base 1 is made of ceramic, and the electrode layer 2 is formed on the base surface of the base 1. Since the base 1 is made of non-metallic material, the ceramic base 1 has high thermal conductivity and high insulation, which can directly achieve insulation between the electrode layer 2 and the target component (the target component is the location where the electrostatic chuck is to be installed, and the target component can be, but is not limited to, semiconductor devices). There is no need to set an insulating layer between the base 1 and the electrode layer 2, and therefore no need to set an adhesive layer, which can avoid the problem of adhesive layer failure from the source.

[0036] Electrode layer 2 is formed on the base surface of substrate 1 by deposition or printing processes. The deposition process can be, but is not limited to, physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD). The printing process is specifically screen printing. During the actual construction, a specific mask is selected to define the pattern of electrode layer 2. The pattern of electrode layer 2 can adopt a multi-electrode segmentation structure.

[0037] The deposition or printing process achieves the integrated integration of electrode layer 2 and base 1, which can ensure a stable bond between electrode layer 2 and base 1.

[0038] The dielectric layer 3 covers the outer surface of the electrode layer 2 relative to the base 1. The outer surface of the electrode layer 2 relative to the base 1 refers to the exposed surface of the electrode layer 2 after it is processed on the base 1.

[0039] The dielectric layer 3 provides insulation protection for the electrode layer 2 and provides electrostatic attraction. The dielectric layer 3 is formed by at least one of a spraying process and a deposition process. The spraying process may include, but is not limited to, atmospheric plasma spraying (APS) or suspension plasma spraying (SPS); the deposition process may include, but is not limited to, aerosol deposition (AD), physical vapor deposition, chemical vapor deposition, or atomic layer deposition.

[0040] The dielectric layer 3 is made of ceramic material. The thermal expansion coefficient of the dielectric layer 3 is close to that of the base 1, which can avoid the problem of adhesive layer delamination and cracking caused by thermal stress due to the mismatch of thermal expansion coefficients.

[0041] This design solves the problem of adhesive layer failure in electrostatic chucks in related technologies, and helps to extend the service life of electrostatic chucks under harsh thermal cycling conditions.

[0042] In this embodiment of the invention, the base 1 is prepared from at least one of alumina (chemical formula Al2O3), aluminum nitride (chemical formula AlN), glass ceramic, yttrium oxide (chemical formula Y2O3), silicon carbide (chemical formula SiC), zirconium oxide (chemical formula ZrO2), and yttrium aluminum garnet (abbreviated as YAG).

[0043] Specifically, the base 1 can be prepared using one of alumina, aluminum nitride, glass ceramics, yttrium oxide, silicon carbide, zirconium oxide, and yttrium aluminum garnet, or it can be prepared using two, three, or even more of the following: alumina, aluminum nitride, glass ceramics, yttrium oxide, silicon carbide, zirconium oxide, and yttrium aluminum garnet.

[0044] Specifically, the base 1 can be made of aluminum nitride and prepared by hot pressing sintering process to form aluminum nitride ceramic, which has a coefficient of thermal expansion (CTE) of about 4.5 parts per million per degree Celsius (ppm / ℃).

[0045] In this embodiment, the substrate 1 is formed by hot pressing sintering or tape-casting and stacking sintering. These processes enable the fabrication of a high-density monolithic ceramic structure. The high density of the substrate 1 provides excellent mechanical strength and structural stability, and facilitates higher and more uniform thermal conductivity, thus providing a basis for precise control of wafer temperature.

[0046] Specifically, the hot-pressing sintering process needs to be carried out in a dedicated hot-pressing sintering furnace. It densifies the material through the synergistic effect of two physical mechanisms: heating and pressurization. Specifically, the raw material powder is heated to near its melting point, activating the atoms on the surface of the powder particles, making them easier to diffuse and migrate. Simultaneously, mechanical pressure is applied through a mold. This mechanical pressure directly and physically compresses the powder particles, breaking down the oxide film on their surface, forcing the particles to undergo plastic deformation, filling voids, expelling pores, and ultimately fusing them into a dense solid. Cooling is then maintained under pressure, and the material is finally removed from the mold.

[0047] The tape casting and sintering process involves mixing raw material powder with organic binders and solvents to form a slurry, which is then scraped into extremely thin and uniform green ceramic tapes using a scraper. Multiple layers of green ceramic tapes are then stacked in a designed sequence. Under specific temperature and pressure, the stacked green ceramic tapes are pressed into a single, integral green body. This body is then placed in a high-temperature furnace, where the organic binder is first removed, followed by high-temperature sintering to densify it.

[0048] In this embodiment of the invention, the electrode layer 2 can be made of metal or conductive ceramic.

[0049] Specifically, when the electrode layer 2 is made of metal, it may be, but is not limited to, tungsten (element symbol W), molybdenum (element symbol Mo), or platinum (element symbol Pt); when the electrode layer 2 is made of conductive ceramic, it may be, but is not limited to, silicon carbide, indium tin oxide (ITO), or fluorine-doped tin oxide (FTO).

[0050] The thickness of electrode layer 2 can be set to 10~50 micrometers.

[0051] In a further embodiment, the dielectric layer 3 includes a first dielectric layer 31 and a second dielectric layer 32.

[0052] The first dielectric layer 31 covers the outer surface of the electrode layer 2 relative to the base 1, and is formed by a spraying process. The spraying process can be, but is not limited to, atmospheric plasma spraying or suspension plasma spraying. In this way, the main thickness of the dielectric layer 3 can be efficiently constructed, providing the main insulation strength and mechanical support for the entire dielectric layer 3.

[0053] The second dielectric layer 32 covers the surface of the first dielectric layer 31 away from the substrate 1, and is formed by a deposition process. The deposition process can be, but is not limited to, physical vapor deposition, atomic layer deposition, or aerosol deposition. This forms an extremely dense and ultra-smooth functional layer that effectively seals any micropores in the first dielectric layer 31 that may exist due to the spraying process. This prevents plasma penetration, improves the plasma etching resistance, lifespan, and stability of the dielectric layer 3, and reduces the risk of damage to the dielectric layer 3 under harsh environments.

[0054] This configuration, combined with the first dielectric layer 31 and the second dielectric layer 32 formed by different processes, can both ensure the processing efficiency of the dielectric layer 3 and reduce the porosity of the surface of the dielectric layer 3, thereby ensuring the compactness, stability and anti-plasma etching performance of the surface of the dielectric layer 3.

[0055] In this embodiment, the first dielectric layer 31 is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride (chemical formula YF3), yttrium oxyfluoride (chemical formula YOF), yttrium aluminum garnet, yttrium aluminate (abbreviated as YAP, chemical formula YAlO3), and monoclinic yttrium aluminate (abbreviated as YAM, chemical formula Y4Al2O9).

[0056] Specifically, the first dielectric layer 31 can be prepared using one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium aluminate. Alternatively, the first dielectric layer 31 can be prepared using two, three, or even more of the following: aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium aluminate.

[0057] The second dielectric layer 32 is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium aluminate.

[0058] Specifically, the second dielectric layer 32 can be prepared using one of the following: aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium. Alternatively, the second dielectric layer 32 can be prepared using two, three, or even more of the following: aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate, and monoclinic yttrium.

[0059] It should be noted that the materials used for the first dielectric layer 31 and the second dielectric layer 32 can have the same or different compositions, depending on the specific requirements. The particle size of the raw material powder used to prepare the second dielectric layer 32 should be smaller than that of the raw material powder used for the first dielectric layer 31.

[0060] In this embodiment, the thickness of the first dielectric layer 31 is 50~500 micrometers. Specifically, the thickness of the first dielectric layer 31 can be processed to 300 micrometers.

[0061] The thickness of the second dielectric layer 32 is 20~200 micrometers. Specifically, the thickness of the second dielectric layer 32 can be processed to 80 micrometers.

[0062] In this embodiment, the porosity of the first dielectric layer 31 only needs to be less than 8%, which is a low requirement for the porosity of the first dielectric layer 31 and is beneficial to improving the construction efficiency of the first dielectric layer 31.

[0063] The porosity of the second dielectric layer 32 is less than 2%. The requirement for the porosity of the second dielectric layer 32 is relatively high, which can improve the density and stability of the surface of the second dielectric layer 32.

[0064] Specifically, the porosity of the first dielectric layer 31 can be 3%, and the porosity of the second dielectric layer 32 can be 0.2%.

[0065] In this embodiment, the base 1 is provided with a connection hole 4, a pin hole 5, and an electrode terminal 6, such as... Figure 1 As shown.

[0066] The connecting hole 4 is used to connect the base 1 to the target component, thereby achieving stable installation and precise positioning of the electrostatic chuck in the target component. The connecting hole 4 can be a threaded hole.

[0067] Pin hole 5, also known as pin hole, penetrates the base 1, electrode layer 2 and dielectric layer 3. Pin hole 5 provides a movement channel for the lifting pin of the wafer lifting mechanism, which can smoothly complete the automatic loading and unloading of wafers and help improve production efficiency.

[0068] The base 1 is provided with an electrode terminal hole that penetrates the base 1. The electrode terminal 6 is disposed in the electrode terminal hole, and one end of the electrode terminal 6 is in electrical contact with the electrode layer 2, forming a path for reliably applying high voltage to the electrode layer 2 to generate a stable and uniform electrostatic adsorption force, ensuring that the wafer is firmly adsorbed during the processing.

[0069] The aforementioned connecting hole 4, ejector pin hole 5, and electrode terminal hole are formed by precision grinding equipment.

[0070] The surface roughness of the dielectric layer 3 on the side away from the base 1 needs to be less than 0.1 micrometers, that is, the surface roughness of the second dielectric layer 32 on the side away from the base 1 needs to be less than 0.1 micrometers.

[0071] In summary, the electrostatic chuck provided by the embodiments of the present invention can eliminate thermal stress caused by the presence of the adhesive layer and the mismatch of thermal expansion coefficients, avoid the risk of delamination and cracking, and extend the service life of the electrostatic chuck under harsh thermal cycling conditions. At the same time, it avoids the problems of high cost, high energy consumption, and complex process control of traditional co-firing processes, achieving high-performance, high-reliability, and low-cost electrostatic chuck fabrication.

[0072] The electrostatic chuck provided in this embodiment of the invention, through the synergistic design of the structure of the base 1 and the dielectric layer 3, achieves excellent properties such as insulation and density close to those of co-fired ceramics, while avoiding the problems of high cost, high energy consumption, and complex process control of co-fired processes. It realizes the preparation of high-performance, high-reliability, and low-cost electrostatic chucks, meeting the requirements for higher power plasma environments, stricter temperature control accuracy, and lower particulate contamination. It is suitable for various demanding semiconductor equipment such as etching, chemical vapor deposition, and physical vapor deposition.

[0073] On the other hand, the present invention also provides a method for preparing an electrostatic chuck for preparing the electrostatic chuck provided in any of the above embodiments. The method for preparing the electrostatic chuck described below can be referred to in correspondence with the electrostatic chuck described above.

[0074] like Figure 4 As shown, the method for preparing an electrostatic chuck provided in this embodiment of the invention includes steps 110 to 140.

[0075] Step 110: Prepare a ceramic base and machine connection holes, pin holes and electrode terminal holes on the base.

[0076] Step 120: Prepare an electrode layer on the substrate surface using a deposition or printing process.

[0077] Step 130: Prepare the first dielectric layer on the outer surface of the electrode layer using a spray coating process.

[0078] Step 140: A second dielectric layer is prepared on the surface of the first dielectric layer away from the substrate using a deposition process.

[0079] The derivation process of the beneficial effects of the preparation method of the electrostatic chuck in the embodiments of the present invention is largely similar to the derivation process of the beneficial effects of the electrostatic chuck described above, so it will not be repeated here.

[0080] Between steps 120 and 130, sandblasting is required on the area of ​​the base 1 where the electrode layer 2 is not located to reduce its surface roughness to greater than 3 micrometers, thereby improving the interlayer bonding force between the first dielectric layer 31 and the base 1. During sandblasting, the surface of the electrode layer 2 needs to be protected to prevent sandblasting of the electrode layer 2.

[0081] Between steps 130 and 140, a precision sandblasting process is required on the surface of the first dielectric layer 31 to increase the surface roughness while reducing the amount of material removed, thereby enhancing the interlayer bonding force between the second dielectric layer 32 and the first dielectric layer 31.

[0082] After step 140, the processed electrostatic chuck is ground and polished, and then degreased, chemically cleaned and ultrasonically cleaned, and dried in a vacuum drying oven.

[0083] Finally, the dried electrostatic chuck can be inspected to check its key dimensions, flatness, and other characteristics. Optical inspection equipment is used to test its surface roughness, and electrical performance tests such as withstand voltage, dielectric constant, and dielectric loss are performed. Finally, a wafer adsorption / desorption test is conducted to ensure its performance in use.

[0084] The specific steps of the preparation method of the electrostatic chuck provided in this embodiment are described in detail below.

[0085] The first step is to process the base 1. High-purity aluminum nitride powder is dry-pressed and then hot-pressed and sintered at 1850℃ under a nitrogen protective atmosphere to obtain a dense ceramic blank. Subsequently, a computer numerical control (CNC) engraving machine is used to process the ceramic blank into a certain shape and to complete the processing of threaded holes, ejector pin holes 5, and electrode terminal holes.

[0086] The second step is to prepare electrode layer 2. The processed ceramic substrate 1 is degreased and ultrasonically cleaned. Using a high-purity tungsten target, metallic tungsten is deposited on the surface of the substrate 1 protected by a mask by magnetron sputtering, with the deposition thickness controlled to be 10-50 micrometers, to form electrode layer 2.

[0087] The third step is surface roughening treatment. The deposited electrode layer 2 is protected by sandblasting the non-electrode areas on the ceramic substrate 1 with 40-80 mesh diamond abrasive to control the surface roughness of the non-electrode areas on the ceramic substrate 1 to be greater than 5 micrometers.

[0088] The fourth step is to prepare the first dielectric layer 31. The ceramic substrate 1 with the electrode layer 2 is fixed to the worktable of an atmospheric plasma spraying equipment. Yttrium oxide powder with a particle size of 15-45 micrometers is used. The plasma power is set to 35 kilowatts, the spraying distance to 100 millimeters, and the powder feed rate to 30 grams per minute. The spray gun is controlled by a robot program to perform reciprocating scanning until the coating thickness reaches 300 micrometers.

[0089] The fifth step involves treating the surface of the first dielectric layer 31. A light sandblasting treatment is performed on the surface of the first dielectric layer 31 using 100-200 mesh diamond abrasive, controlling the surface roughness of the first dielectric layer 31 to 3.5 micrometers. This helps clean the surface of the first dielectric layer 31 and improves the adhesion of the second dielectric layer 32 to the first dielectric layer 31. Then, the sandblasted surfaces of the base 1 and the first dielectric layer 31 are degreased and ultrasonically cleaned.

[0090] Step 6: Prepare the second dielectric layer 32. Transfer the substrate 1 with the first dielectric layer 31 to the chamber of the aerosol deposition apparatus. Mix yttrium oxide powder with a carrier gas to form an aerosol, and deposit it onto the surface of the first dielectric layer 31 at high speed at room temperature. Control the number of depositions to achieve a thickness of 80 micrometers. The particle size of the yttrium oxide powder used to prepare the second dielectric layer 32 is smaller than that of the yttrium oxide powder used to prepare the first dielectric layer 31. Specifically, the particle size of the yttrium oxide powder used to prepare the second dielectric layer 32 can be in the nanometer range.

[0091] Step 7: Post-processing of the electrostatic chuck. The surface of the electrostatic chuck with the second dielectric layer 32 deposited is finely ground and polished to achieve an overall flatness better than 0.02 mm and a final surface roughness of 0.08 micrometers.

[0092] Step 8: Cleaning and drying the electrostatic chuck. The electrostatic chuck is subjected to degreasing cleaning, chemical cleaning, and ultrasonic cleaning with ultrapure water in sequence. Finally, the electrostatic chuck is transferred to a vacuum oven and dried at 120°C for 12 hours.

[0093] Step nine involves verifying the performance of the electrostatic chuck. The dimensions of the electrostatic chuck are measured using a coordinate measuring machine. The dielectric constant and dielectric loss of the electrostatic chuck are tested using an impedance analyzer. The wafer adsorption / desorption performance and temperature uniformity are tested in a vacuum simulation chamber.

[0094] Tests have shown that the electrostatic chuck prepared by the electrostatic chuck preparation method provided in this embodiment of the invention does not exhibit cracking or delamination after 500 rapid thermal cycles between room temperature and 200°C. Furthermore, it demonstrates excellent corrosion resistance and stable electrical insulation performance in a plasma etching simulation environment. The electrostatic chuck prepared by the electrostatic chuck preparation method provided in this embodiment of the invention has advantages in terms of high reliability and long lifespan.

[0095] To further verify the advantages of the electrostatic chuck prepared by the electrostatic chuck preparation method provided in the embodiments of the present invention, a comparative experiment was conducted.

[0096] The electrostatic chucks obtained through steps one through nine above were used as the experimental group. Additionally, an electrostatic chuck with a ceramic base 1 but only one dielectric layer 3 was prepared as control group one; and an electrostatic chuck with a metal base 1' and two dielectric layers 3 was prepared as control group two.

[0097] Specifically, the structure of the electrostatic chuck in control group one is as follows: Figure 2 As shown, the electrostatic chuck includes a ceramic base 1, an electrode layer 2, and a dielectric layer 3. The ceramic base 1 has connection holes 4, pin holes 5, and electrode terminals 6. The ceramic base 1 is made of the same material as the base 1 in the experimental group, and the manufacturing process is the same, with the same structure and channel design. The material and manufacturing process of the electrode layer 2 are the same as those in the experimental group. In control group one, only an atmospheric plasma spraying process was used, employing yttrium oxide powder to prepare a dielectric layer 3 with a thickness of 400 micrometers. That is, the dielectric layer 3 of the electrostatic chuck in control group one is approximately the same as the sum of the thicknesses of the two dielectric layers 3 in the experimental group's electrostatic chuck, and the porosity of the dielectric layer 3 is controlled at 3%. The surface of the electrostatic chuck in control group one was ground and polished under the same conditions as the electrostatic chuck in the experimental group.

[0098] The specific steps for preparing the electrostatic chuck of control group one are as follows.

[0099] The first step is the same as the first step in the preparation of the electrostatic chuck in the experimental group.

[0100] The second step is the same as the second step in the preparation of the electrostatic chuck in the experimental group.

[0101] The third step is the same as the third step in the preparation of the electrostatic chuck in the experimental group.

[0102] In the fourth step, the same atmospheric plasma spraying parameters as those in the fourth step of the preparation of the electrostatic chuck in the experimental group were used. By controlling the number of sprayings, the thickness of the single dielectric layer 3 was controlled at 400 micrometers.

[0103] The fifth step is the same as the seventh step in the preparation of the electrostatic chuck for the experimental group.

[0104] Step six is ​​the same as step eight in the preparation of the electrostatic chuck for the experimental group.

[0105] Step seven is the same as step nine in the preparation of the electrostatic chuck for the experimental group.

[0106] The structure of the electrostatic chuck in control group two is as follows: Figure 3 As shown, the structure includes a metal base 1', an insulating layer 7', an electrode layer 2', and two dielectric layers 3'. The metal base 1' has threaded holes 4', pin holes 5', and electrode terminals 6'. The metal base 1' is made of 6061-T6 aluminum alloy with a coefficient of thermal expansion of 23 ppm / ℃. The metal base 1' has the same structure and channel design as the base 1 in the experimental group. The insulating layer 7' is prepared using a tape-casting and sintering process or a hot-pressing and sintering process. After sintering, it undergoes precision grinding to ensure flatness and parallelism, and is then bonded to the metal base 1' by adhesive. The material and preparation process of the electrode layer 2' are the same as those of the electrode layer 2 in the experimental group. The material, parameters, and processes of the two dielectric layers 3' are the same as those of the two dielectric layers 3 in the experimental group.

[0107] The specific steps for preparing the electrostatic chuck for control group two are as follows.

[0108] The first step involves using 6061-T6 aluminum alloy to machine threaded holes 4', pin holes 5', and electrode terminal holes, and then anodizing the aluminum alloy surface.

[0109] The second step involves using 20-60 mesh diamond abrasive to roughen the surface of the metal base 1' by sandblasting, controlling the roughness to be greater than 5 micrometers.

[0110] The third step involves using a tape-casting and lamination sintering process or a hot-pressing sintering process to prepare an insulating layer 7' with a thickness of 10 mm on the surface of the metal base 1'. After sintering, the layer is then precision ground.

[0111] The fourth step is the same as the second step in the preparation of the electrostatic chuck for the experimental group.

[0112] The fifth step is the same as the third step in the preparation of the electrostatic chuck in the experimental group.

[0113] Step six is ​​the same as step four in the preparation of the electrostatic chuck for the experimental group.

[0114] Step 7 is the same as step 5 in the preparation of the electrostatic chuck for the experimental group.

[0115] Step 8 is the same as step 6 in the preparation of the electrostatic chuck for the experimental group.

[0116] Step nine is the same as step seven in the preparation of the electrostatic chuck for the experimental group.

[0117] Step 10 is the same as step 8 in the preparation of the electrostatic chuck for the experimental group.

[0118] Step eleven is the same as step nine in the preparation of the electrostatic chuck for the experimental group.

[0119] The performance test results of the electrostatic chucks in the above experimental group, control group 1, and control group 2 are shown in the table below.

[0120] The above comparative tests demonstrate that the electrostatic chuck provided in the embodiments of the present invention and the electrostatic chuck prepared by the preparation method of the electrostatic chuck provided in the embodiments of the present invention have successfully achieved the expected purpose and obtained the following beneficial effects.

[0121] By adopting a ceramic base 1, the traditional metal base 1' and ceramic insulation layer structure are completely eliminated, thus eliminating the thermal stress caused by the presence of adhesive layer and the mismatch of thermal expansion coefficients, avoiding the risk of delamination and cracking, and extending the service life of the electrostatic chuck under harsh thermal cycling conditions.

[0122] A composite dielectric layer is prepared using a combination of spraying and deposition processes. The sprayed coating, serving as the bottom dielectric layer, efficiently constructs a coating of sufficient thickness and low porosity, achieving the same thickness as sintered ceramic dielectric layers while maintaining good density, providing insulation and dielectric properties for the substrate. The deposited layer, serving as the top dielectric layer, utilizes its vacuum deposition characteristics to prepare an extremely dense, highly stable, and highly plasma-resistant functional ceramic layer (i.e., the second dielectric layer 32) on the first dielectric layer 31. This layer effectively blocks plasma, improving the lifetime and stability of the dielectric layer 3 and reducing the risk of damage. Through the complementary functions of the two dielectric layers, density, insulation, and surface quality approaching or even surpassing those of high-temperature co-fired ceramics are achieved, while avoiding the high cost, high energy consumption, and deformation control challenges of co-firing processes; it also overcomes the drawbacks of high porosity in single thermal spray coatings and the difficulty in achieving thick deposition with single deposited coatings.

[0123] By employing a ceramic base 1 and a spray-deposited composite dielectric layer in a synergistic design, the overall performance is comprehensively optimized, meeting the higher requirements of advanced semiconductor manufacturing processes for electrostatic chucks—superior resistance to plasma erosion, lower particulate contamination, more precise temperature control, and higher power tolerance. It is suitable for various demanding semiconductor equipment such as etching, chemical vapor deposition, and physical vapor deposition.

[0124] In summary, the embodiments of the present invention provide a high-performance electrostatic chuck solution that achieves the best balance in terms of reliability, performance, manufacturing cost and process controllability, and has excellent industrial application value.

[0125] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. An electrostatic chuck, characterized in that, include: The base (1) is made of ceramic. An electrode layer (2) is disposed on the base surface of the base (1); The dielectric layer (3) is made of ceramic material and covers the outer surface of the electrode layer (2) relative to the base (1). The dielectric layer (3) is formed by at least one of spraying and deposition processes.

2. The electrostatic chuck according to claim 1, characterized in that, The base (1) is made of at least one of alumina, aluminum nitride, glass ceramic, yttrium oxide, silicon carbide, zirconium oxide and yttrium aluminum garnet.

3. The electrostatic chuck according to claim 2, characterized in that, The base (1) is formed by hot pressing sintering or tape stacking sintering.

4. The electrostatic chuck according to claim 1, characterized in that, The electrode layer (2) is formed on the base (1) by a deposition process or a printing process, and the material of the electrode layer (2) is metal or conductive ceramic.

5. The electrostatic chuck according to claim 1, characterized in that, The dielectric layer (3) includes: A first dielectric layer (31) is formed by spraying on the outer surface of the electrode layer (2) relative to the base (1). The second dielectric layer (32) covers the surface of the first dielectric layer (31) away from the base (1), and the second dielectric layer (32) is formed by a deposition process.

6. The electrostatic chuck according to claim 5, characterized in that, The first dielectric layer (31) is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate and monoclinic yttrium aluminate; The second dielectric layer (32) is prepared from at least one of aluminum oxide, aluminum nitride, silicon carbide, zirconium oxide, yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium aluminum garnet, yttrium aluminate and monoclinic yttrium aluminate.

7. The electrostatic chuck according to claim 5, characterized in that, The thickness of the first dielectric layer (31) is 50~500 micrometers, and the thickness of the second dielectric layer (32) is 20~200 micrometers.

8. The electrostatic chuck according to claim 5, characterized in that, The porosity of the first dielectric layer (31) is less than 8%, and the porosity of the second dielectric layer (32) is less than 2%.

9. The electrostatic chuck according to any one of claims 1-8, characterized in that, The base (1) is provided with a connection hole (4), a pin hole (5) and an electrode terminal (6). The connection hole (4) is used to connect the base (1) to the target component. The pin hole (5) passes through the base (1), the electrode layer (2) and the dielectric layer (3). The electrode terminal (6) passes through the base (1) and one end of the electrode terminal (6) is in electrical contact with the electrode layer (2).

10. A method for preparing an electrostatic chuck, characterized in that, The method for preparing the electrostatic chuck as described in any one of claims 1-9 includes: A ceramic base is prepared, and connection holes, pin holes, and electrode terminal holes are machined on the base; An electrode layer is prepared on the base surface of the substrate using a deposition or printing process; A first dielectric layer is prepared on the outer surface of the electrode layer using a spray coating process; A second dielectric layer is prepared on the surface of the first dielectric layer away from the substrate using a deposition process.

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