Electrostatic chuck and thin film deposition equipment

Abstract

The invention discloses an electrostatic chuck and thin film deposition equipment, the electrostatic chuck comprises a base, a circular ring and a chuck body, the circular ring is fixedly arranged on the upper surface of the base, the chuck body is installed in the circular ring, the upper surface of the chuck body is used for supporting a wafer, and the base is configured as a grounding end of plasma; wherein the upper surface of the base is of a plane structure, and the outer side wall of the circular ring is flush with the outer side wall of the base, so that the plasma on the edge of the wafer is far away from the grounding end. A surrounding edge structure that the base surrounds the circular ring is omitted, the length of a loop to ground of the chuck body is increased, plasma on the edge of the wafer is made to be away from the grounding end, the farther the plasma is away from the grounding end, the higher the energy density is, and therefore the plasma energy density of the edge of the wafer is improved, and the uniformity of a film is improved. The quality of thin film deposition is improved, and the problems of leakage current and high back helium leakage rate are solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an electrostatic chuck and a thin film deposition device. Background Art

[0002] In modern semiconductor device manufacturing, forming thin films on semiconductor wafers through chemical reactions of gases is a key step. This type of deposition process is called Chemical Vapor Deposition (CVD). In the traditional CVD process, the reaction gas flows over the surface of the wafer and undergoes a thermochemical reaction on the surface of the wafer to generate the desired film. On the other hand, the plasma-enhanced chemical vapor deposition (PECVD) technology promotes the excitation or dissociation of the reaction gas by applying radio frequency (RF) energy to the reaction area close to the wafer surface to generate plasma. Compared with the traditional thermal CVD process, the high reactivity in the plasma can significantly reduce the energy required for the chemical reaction, thereby reducing the temperature required for this type of CVD process. To further utilize these advantages, high-density plasma chemical vapor deposition (HDP CVD) technology came into being. In the HDP CVD process, by forming a high-density plasma under low vacuum pressure, the plasma is made more active, thereby further improving the deposition rate and film quality. In some CVD applications, an electrostatic chuck (ESC) is used to support the wafer in the reaction chamber. However, for a long time, electrostatic chucks have had certain problems in process uniformity, affecting the uniformity and overall performance of the film. Summary of the invention

[0003] The embodiments of the present invention provide an electrostatic chuck and a thin film deposition device, aiming to solve the problem that the conventional electrostatic chuck process has poor uniformity and affects the uniformity of the thin film.

[0004] In a first aspect, the present invention provides an electrostatic chuck, comprising: a base, a ring and a chuck body, wherein the ring is fixedly arranged on the upper surface of the base, the chuck body is installed in the ring, the upper surface of the chuck body is used to support a wafer, and the base is configured as a grounding end of the plasma;

[0005] The upper surface of the base is a planar structure, and the outer side wall of the ring is flush with the outer side wall of the base, so that the plasma at the edge of the wafer is away from the ground end.

[0006] Furthermore, an outer ring positioning step is provided on the outer edge of the upper surface of the base, and a first inner ring positioning step is provided on the inner edge of the lower surface of the circular ring, and the first inner ring positioning step is matched with the outer ring positioning step in a stepped manner.

[0007] Furthermore, the upper surface of the base and the lower surface of the circular ring form a fitting step interface, and the first inner ring positioning step protrudes downward from the step interface and cooperates with the outer ring positioning step.

[0008] Furthermore, the electrostatic chuck also includes an isolation plate, which is installed in the ring and disposed between the chuck body and the base to isolate the chuck body from the base.

[0009] Furthermore, a second inner ring positioning step is provided on the inner side of the circular ring, and the side wall and the top wall of the isolation plate are respectively fitted and positioned with the second inner ring positioning step.

[0010] Furthermore, at least one layer of annular heat-insulating grooves is provided on the inner side of the circular ring, and a heat-insulating ring is provided in each of the heat-insulating grooves.

[0011] Furthermore, a chamfer is provided at the intersection and transition between the outer side wall of the circular ring and the top wall thereof.

[0012] Furthermore, the maximum outer diameter of the circular ring is the same as the maximum outer diameter of the base, and a boss for supporting the wafer is provided on the inner edge of the upper surface of the circular ring, and the boss is lower than the upper surface of the chuck body.

[0013] Furthermore, a wafer positioning portion is provided on the outer side of the boss, and the height of the wafer positioning portion is higher than the height of the boss.

[0014] In a second aspect, the present invention also provides a thin film deposition device, comprising the electrostatic chuck

[0015] The present invention provides an electrostatic chuck and a thin film deposition device. The electrostatic chuck comprises: a base, a ring and a chuck body. The upper surface of the chuck body is used to support a wafer. The base serves as a grounding end of plasma. The ring is fixed on the upper surface of the base. The chuck body is installed in the ring. Compared with the existing base with a surrounding edge structure, the upper surface of the base of the present application is a planar structure, and the outer side wall of the ring is flush with the outer side wall of the base, so that the base is a flat-top structure without a surrounding edge, and the surrounding edge structure of the base surrounding the ring is omitted. In this way, the plasma at the edge of the wafer on the upper surface of the chuck body is farther from the base, which increases the length of the chuck body to the ground loop, so that the plasma at the edge of the wafer is far away from the grounding end. The farther the plasma is from the grounding end, the higher its energy density is, so the plasma energy density at the edge of the wafer is improved, thereby improving the uniformity of the film and improving the quality of film deposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0017] Figure 1 A cross-sectional schematic diagram of an existing electrostatic chuck is shown;

[0018] Figure 2 Shown Figure 1 A magnified view of part A;

[0019] Figure 3 A schematic side view of an electrostatic chuck according to an embodiment of the present invention is shown;

[0020] Figure 4 A schematic top view of an electrostatic chuck according to an embodiment of the present invention is shown;

[0021] Figure 5 Shown Figure 4 BB cross-sectional view;

[0022] Figure 6 Shown Figure 5 A magnified view of part B;

[0023] Figure 7 Shown Figure 5 Enlarged view of part C;

[0024] Figure 8 Shown Figure 5 A magnified view of the D portion;

[0025] Reference numerals:

[0026] 1. Base; 11. Edge; 12. Outer ring positioning step; 121. First outer ring step surface; 122. Second outer ring step surface; 2. Circular ring; 21. First inner ring positioning step; 211. First inner ring step surface; 212. Second inner ring step surface; 22. Second inner ring positioning step; 221. Third inner ring step surface; 222. Fourth inner ring step surface; 23. Heat insulation groove; 24. Chamfer; 25. Boss; 3. Chuck body; 4. Isolation plate; 5. Annular upper cover. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The directional terms mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, but are not used to limit the present invention. In addition, in the drawings, structures with similar or identical structures are represented by the same reference numerals.

[0029] In order to facilitate understanding of the embodiments of the present invention, a brief introduction to the existing electrostatic chuck is first given. Electrostatic chuck (ESC) is a device that uses electrostatic adsorption force to fix and support the wafer, and is widely used in thin film deposition, etching and other processes in semiconductor manufacturing. The core principle of the electrostatic chuck is to use electrostatic attraction to fix the wafer. When a voltage is applied to the chuck body, an electrostatic field is formed between the chuck body and the wafer. This electrostatic field generates an electrostatic force to tightly adsorb the wafer to the chuck body.

[0030] In high-density plasma chemical vapor deposition (HDP CVD) equipment, plasma plays a vital role. The high-energy electrons in the plasma can effectively decompose the reaction gas molecules to produce active groups and free radicals. These active species are crucial for the chemical reactions in the deposition process and can promote the nucleation and growth of the deposited material on the substrate surface. Due to the presence of plasma, the activation degree of the reactant molecules can be significantly increased, thereby accelerating the deposition rate. At the same time, high-density plasma can also provide more reactive species to further improve the deposition efficiency. By precisely controlling the plasma conditions (such as power, pressure, temperature, etc.), the microstructure and properties of the deposited film can be effectively controlled, such as reducing the defect density, improving the uniformity and density of the film, etc. Using the energy of plasma, deposition can be performed at a lower temperature, which is particularly important for some temperature-sensitive substrate materials.

[0031] High-density plasma means more charged particles (electrons and ions) and active species. These particles can activate the reaction gas more effectively and provide more deposition precursors, thereby improving the deposition rate and the quality of the film. High-density plasma can generally provide a more uniform particle distribution, which helps to form a more uniform film on the substrate. Low-density plasma may not provide enough active species, resulting in a reduced deposition rate, and may be unevenly distributed on the substrate, thus affecting the uniformity of the film. It can be seen that the plasma density directly affects the spatial distribution of active species in the plasma. High-density plasma can generally provide a more uniform particle distribution, which helps to form a more uniform film on the substrate.

[0032] In a plasma system, the density of the plasma usually changes with the distance from the ground terminal. Specifically, the plasma density tends to decrease near the ground terminal. In a plasma system, the electric field strength is usually strongest near the discharge source (such as radio frequency) and gradually weakens near the ground terminal. The weakening of the electric field strength will cause the acceleration and collision frequency of the charged particles (electrons and ions) in the plasma to decrease, thereby reducing the plasma density. That is, the closer the plasma field is to the ground terminal, the lower the energy density and the worse the film uniformity; the farther the plasma field is from the ground terminal, the higher the energy density and the better the film uniformity. Therefore, the distance between the plasma field and the ground terminal affects the uniformity of the film.

[0033] Reference Figure 1 and Figure 2 Currently, the existing electrostatic chuck usually includes a base 1, a ring 2, a chuck body 3, an isolation plate 4 and an annular upper cover 5. The base 1 is a structure with an open groove in the center, similar to a box or bowl. The ring 2 is installed inside the groove. The base 1 has a circle of surrounding edge 11 structure surrounding the outside of the ring 2. The chuck body 3 and the isolation plate 4 are both arranged on the inner side of the ring 2. The isolation plate 4 is isolated between the chuck body 3 and the base 1. The annular upper cover 5 covers the upper surface of the ring 2 and the upper surface of the surrounding edge 11 of the base 1. The wafer is placed on the upper surface of the chuck body 3, and the chuck body 3 supports the wafer by electrostatic adsorption. The base 1 serves as the grounding end of the plasma, providing a reference potential to ensure that the charged particles (electrons and ions) in the plasma can act effectively. The distance between the wafer edge plasma and the grounding end is the distance between the wafer edge and the vertex of the surrounding edge 11 of the base 1, such as Figure 2The dotted line grounding path L1 is shown. The groove structure of the base 1 provides a peripheral edge 11 surrounding the ring 2, and the peripheral edge 11 has a certain height, which is slightly lower than the height of the ring 2. This structure makes the distance between the wafer edge and the vertex of the peripheral edge 11 closer, the grounding length is short, and the distance of the plasma field grounding at the wafer edge is short. The closer the plasma is to the terminal, the lower its energy density, so the uniformity of the film at the wafer edge is poor.

[0034] To this end, an embodiment of the present invention proposes an electrostatic chuck and a thin film deposition device, which solves the problem that the existing electrostatic chuck process has poor uniformity and affects the uniformity of the thin film. By setting the base 1 as a planar structure without a surrounding edge 11, the distance between the plasma field at the edge of the wafer and the ground is increased, and the plasma energy density at the edge of the wafer is increased, thereby improving the uniformity of the thin film.

[0035] The embodiment of the present invention solves the above-mentioned problem of film uniformity, and the specific ideas are as follows:

[0036] The structure of the base 1 is changed, and the existing base 1 structure with a groove in the middle and a surrounding edge 11 is replaced with a flat structure without a surrounding edge 11. That is, the surrounding edge 11 with a certain height on the existing base 1 is simplified, so that the distance between the wafer edge and the base 1 (ground end) is as follows Figure 6 The dotted grounding path L2 shown needs to bypass the entire upper surface and outer side wall of the ring 2 all the way to the base 1. Relative to the distance between the wafer edge of L1 and the vertex of the surrounding edge 11 of the base 1, since there is no surrounding edge 11 with a certain height, the grounding path extends all the way to the edge of the supporting surface of the base 1, extending the grounding length, keeping the wafer edge plasma away from the grounding end, and increasing the wafer edge plasma energy density, thereby improving the uniformity of the film.

[0037] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] See also Figure 3-Figure 8 An embodiment of the present invention shows an electrostatic chuck, comprising: a base 1, a ring 2 and a chuck body 3, wherein the ring 2 is fixedly arranged on the upper surface of the base 1, the chuck body 3 is installed in the ring 2, the upper surface of the chuck body 3 is used to support a wafer, and the base 1 is configured as a grounding end of the plasma; wherein the upper surface of the base 1 is a planar structure, and the outer side wall of the ring 2 is flush with the outer side wall of the base 1, so as to keep the plasma at the edge of the wafer away from the grounding end.

[0039] Reference Figure 5 and Figure 6Specifically, the base 1 and the chuck body 3 are in a disc structure as a whole, and the base 1 and the chuck body 3 are coaxially arranged. The ring 2 is fixed on the upper surface of the base 1, and there are various fixing structures between the ring 2 and the base 1, which are not limited here. The ring 2 is sleeved on the outside of the chuck body 3, that is, the ring 2 is on the outside and the chuck body 3 is on the inside. The inner diameter of the ring 2 is 0.5mm larger than the outer diameter of the chuck body 3, that is, there must be a certain gap between the ring 2 and the chuck body 3. If the gap between the two is too small, the chuck body 3 will not have enough space for thermal expansion, and too large a gap will affect the service life of the electrostatic chuck. The chuck body 3 is used to support the wafer, and the wafer will fall on the upper surface of the chuck body 3, and the edge of the wafer is about 2mm on the upper surface of the ring 2. The upper surface of the base 1 is a planar structure, the ring 2 is fixed on the upper surface of the base 1, the outer wall of the base 1 is aligned with the outer wall of the upper ring 2, or the outer diameter of the base 1 is equal to the outer diameter of the ring 2, which shows that the base 1 of this embodiment is a structure without a peripheral edge 11, the edge of the base 1 does not have a peripheral edge 11 of a certain height, and the upper surface of the entire base 1 is planar. Compared with the grounding length L1 between the edge of the wafer of the existing electrostatic chuck and the vertex of the peripheral edge 11 on the base 1, this embodiment simplifies the peripheral edge 11 on the base 1, so the edge of the wafer needs to bypass the side wall surface of the upper surface of the ring 2 to reach the base 1, extending the grounding length, increasing the distance L2 between the plasma at the edge of the wafer and the grounding end (base 1), increasing the plasma density at the edge of the wafer, increasing the film thickness at the edge of the wafer, making it consistent with the film thickness in the central area, improving the uniformity, uniformity and film thickness range of the film, and improving the quality of film deposition.

[0040] Through this embodiment, by simplifying the structure of the surrounding edge 11 of the base 1, the plasma at the edge of the wafer is kept away from the ground end. The farther the plasma is from the ground end, the higher its energy density is. Therefore, the plasma energy density at the edge of the wafer is increased, thereby improving the uniformity of the thin film and improving the quality of thin film deposition.

[0041] Reference Figure 2 , Figure 6 and Figure 8In one embodiment, the maximum outer diameter of the ring 2 is the same as the maximum outer diameter of the base 1, and the inner edge of the upper surface of the ring 2 is provided with a boss 25 for supporting the wafer, and the boss 25 is lower than the upper surface of the chuck body 3. Specifically, the existing electrostatic chuck assembly usually includes three main components: two ceramic parts (annular upper cover 5 and ring 2) and an aluminum part (base 1). After these parts are assembled together, the height difference between the annular upper cover 5 and the chuck body 3 is difficult to control due to the inconsistent thermal expansion coefficients of ceramic and aluminum. Specifically: the thermal expansion coefficients of ceramic and aluminum are different, which means that when the temperature changes, their expansion degrees are different. As the temperature of the cavity increases, the surrounding edge 11 structure of the base 1 expands faster in the vertical direction. This is because the surrounding edge 11 of the base 1 is thinner and has a larger height in the vertical direction, so the expansion is more obvious. Since the surrounding edge 11 structure of the base 1 expands faster than the ceramic part, the annular upper cover 5 will eventually be lifted up by the surrounding edge 11 structure of the base 1, making it higher than the surface of the chuck body 3, and there is a height difference between the annular upper cover 5 and the chuck body 3. On the one hand, the height difference leads to uneven electric field distribution and increased local electric field strength, which may cause local breakdown and increase leakage current. On the other hand, the height difference leads to poor sealing between the wafer and the chuck body 3, affecting the sealing effect of the back helium gas and causing an increase in the back helium leakage rate. In order to improve the problems of high leakage current and high back helium leakage rate. This embodiment simplifies the surrounding edge 11 structure of the annular upper cover 5 and the base 1. Among them, the maximum outer diameter of the ring 2 is made the same as the maximum outer diameter of the base 1, which simplifies the surrounding edge 11 structure of the base 1, and the base 1 loses the surrounding edge 11 structure with a certain height, which reduces the expansion of the base 1 in the vertical direction and reduces the height difference caused by thermal expansion. At the same time, the upper surface of the ring 2 replaces the original annular upper cover 5, and the inner edge of the upper surface of the ring 2, that is, the side close to the inner ring of the ring 2, is provided with a boss 25, which is used to replace the boss 25 on the original annular upper cover 5. The boss 25 is used to prevent the wafer from directly contacting the upper surface of the ring 2 and scratching or damaging the wafer, and to prevent the wafer from hitting the particle size of the contaminated wafer. The height of the boss 25 is slightly lower than the height of the upper surface of the chuck body 3, slightly lower by 0.05-0.30mm. Of course, it can be understood that it can also be other numerical ranges, which are specifically set according to actual needs. Through the structure of this embodiment, the original three components of the annular upper cover 5, the ring 2, and the base 1 are simplified to two components, the ring 2 and the base 1, which reduces the thermal expansion of the base 1 in the vertical direction, can effectively control the height difference, and improve the leakage current and the high back helium leakage rate.

[0042] In this embodiment, a wafer positioning portion (not shown in the figure) is provided on the outer peripheral side of the boss 25, and the height of the wafer positioning portion is higher than the height of the boss 25. Specifically, a plurality of wafer positioning portions may be provided, for example, three, and the Sanger wafer positioning portions are spaced apart along the circumferential direction of the ring 2. The wafer positioning portion is provided at the outer edge of the boss 25, and the wafer positioning portion needs to be slightly higher than the boss 25. When the wafer is placed on the upper surface of the chuck body 3, the wafer positioning portion can limit the wafer to prevent the wafer from shifting and ensure the quality of thin film deposition.

[0043] Reference Figure 7 In one embodiment, an outer ring positioning step 12 is provided on the outer edge of the upper surface of the base 1, and a first inner ring positioning step 21 is provided on the inner edge of the lower surface of the ring 2, and the first inner ring positioning step 21 is matched with the outer ring positioning step 12 in a stepped manner. Specifically, a fixed structure with stepped matching is adopted between the base 1 and the ring 2 of this embodiment. Specifically, the upper surface of the base 1 is the contact surface with the ring 2, and the base 1 is a disc structure, so an outer ring positioning step 12 is provided on the upper surface of the base 1, and the outer ring positioning step 12 is close to the outer edge of the upper surface of the base 1. The lower surface of the ring 2 is the contact surface with the base 1, so an inner ring positioning step is provided on the lower surface of the ring 2, and the inner ring positioning step is close to the inner side of the lower surface of the ring 2. Through the stepped matching of the outer ring positioning step 12 and the inner ring positioning step, the ring 2 and the base 1 are positioned, and at the same time, the plasma can be isolated to avoid interference with the internal electric field of the chuck body 3, thereby ensuring the stability and reliability of the electrostatic chuck, and the structure is simple and easy to process.

[0044] Continue to refer to Figure 7In this embodiment, the upper surface of the base 1 and the lower surface of the ring 2 form a step interface that fits together, and the first inner ring positioning step 21 protrudes downward from the step interface and cooperates with the outer ring positioning step 12. Specifically, the outer ring positioning step 12 is formed by the outer wall of the base 1 being concave inward, and the outer ring positioning step 12 includes a first outer ring step surface 121 and a second outer ring step surface 122, one side of the first outer ring step surface 121 is vertically connected to the upper surface of the base 1 upward, and the other side of the first outer ring step surface 121 is vertically connected to one side of the second outer ring step surface 122 downward, and the other side of the second outer ring step surface 122 is connected to the outer wall of the base 1, and the second outer ring step surface 122 is parallel to the upper surface of the base 1, so that the first outer ring step surface 121 and the second outer ring step surface 122 form a structure with a concave edge. The first inner ring positioning step 21 is formed by the inner side of the ring 2 being concave outward, and the first inner ring positioning step 21 includes a first inner ring step surface 211 and a second inner ring step surface 212, one side of the first inner ring step surface 211 is vertically connected to the lower surface of the ring 2 upward, the other side of the first inner ring step surface 211 is vertically connected to one side of the second inner ring step surface 212 downward, the other side of the second inner ring step surface 212 is connected to the outer wall of the ring 2, and the second inner ring step surface 212 is parallel to the lower surface of the ring 2, so that the first inner ring step surface 211 and the second inner ring step surface 212 form a structure with a raised edge. When the ring 2 is positioned with the base 1, the upper surface of the base 1 fits with the lower surface of the ring 2, and the interface between the two is the step interface. The first inner ring positioning step 21 forms a convex edge structure protruding from the step interface and matching the concave edge structure formed by the outer ring positioning step 12 in an up-down concave-convex manner. The first inner ring step surface 211 fits with the first outer ring step surface 121, and the second inner ring step surface 212 fits with the second outer ring step surface 122. In this way, since the convex edge structure extends the height of the outer wall of the ring 2, the height of the outer wall of the ring 2 is longer, so that the grounding distance (the upper surface of the ring 2 and the outer wall, L2) that the wafer edge needs to pass is longer, further improving the energy density of the wafer edge plasma and improving the uniformity of the film.

[0045] Reference Figure 5 In one embodiment, the electrostatic chuck further comprises an isolation plate 4, which is installed in the ring 2 and disposed between the chuck body 3 and the base 1 to isolate the chuck body 3 from the base 1. Specifically, the isolation plate 4 is a disc structure, and the isolation plate 4 is also disposed on the inner side of the ring 2. The isolation plate 4 is disposed between the chuck body 3 and the base 1, that is, the isolation plate 4 is in the middle, the card body is on the top, and the base 1 is on the bottom. The isolation plate 4 is used to insulate the chuck body 3 from the base 1 to prevent short circuits and improve the stability and reliability of the electrostatic chuck.

[0046] Reference Figure 7In this embodiment, the inner side of the circular ring 2 is provided with a second inner ring positioning step 22, and the side wall and the top wall of the isolation plate 4 are respectively fitted and positioned with the second inner ring positioning step 22. Specifically, the second inner ring positioning platform is formed by the inner side of the circular ring 2 being concave outward, and the second inner ring positioning platform includes a third inner ring step surface 221 and a fourth inner ring step surface 222, one side of the third inner ring step surface 221 is vertically connected to the lower surface of the circular ring 2 downward, the other side of the third inner ring step surface 221 is vertically connected to one side of the fourth inner ring step surface 222 upward, the other side of the fourth inner ring step surface 222 is connected to the inner side wall of the circular ring 2, and the fourth inner ring step surface 222 is parallel to the lower surface of the circular ring 2, so that the third inner ring step surface 221 and the fourth inner ring step surface 222 form a structure with an inner side concave outward. The diameter of the isolation plate 4 is larger than the diameter of the chuck body 3. The top wall of the isolation plate 4 is fitted with the fourth inner ring step surface 222, and the side wall of the isolation plate 4 is fitted with the third inner ring step surface 221, so as to position the isolation plate 4. This embodiment has a simple structure and is easy to position.

[0047] Reference Figure 8 In one embodiment, at least one layer of annular heat-insulating grooves 23 is provided on the inner side of the circular ring 2, and a heat-insulating ring (not shown in the figure) is provided in each of the heat-insulating grooves 23. Specifically, an annular heat-insulating groove 23 is provided on the inner side of the circular ring 2, which is concave outward. The annular heat-insulating groove 23 can be one layer or multiple layers. The annular heat-insulating groove 23 can be parallel to the base 1, or can have a certain angle with the base 1. A heat-insulating ring is provided in each heat-insulating groove 23, and the heat-insulating ring can be hollow, or the inside of the heat-insulating ring can be filled with heat-insulating material. By adding a heat-insulating ring to the circular ring 2, the heat conduction of the chuck body 3 to the outside can be reduced, and the temperature of the surface of the circular ring 2 can be increased. A higher temperature can promote the cleaning efficiency, so the cleaning efficiency of the surface of the circular ring 2 can be improved.

[0048] Reference Figure 8 In one embodiment, a chamfer 24 is provided at the intersection of the outer wall of the ring 2 and its top wall. Specifically, because sharp edges or corners can cause electric field concentration, the electric field strength in these areas will increase significantly, thereby increasing the risk of local discharge. Therefore, by providing a chamfer 24 on the ring 2, a smooth transition can be achieved, the concentration of the electric field can be reduced, the electric field distribution can be made more uniform, the local electric field strength can be reduced, and the risk of discharge can be reduced. The side surface of the ring 2 can be perpendicular to the base 1, or it can form an angle (which will affect the gas flow around the wafer).

[0049] The embodiment of the present invention further provides a thin film deposition device, comprising the electrostatic chuck of the above embodiment. Specifically, the electrostatic chuck has been described in detail in the above embodiment, and for the sake of brevity of the description, it will not be repeated here.

[0050] Through this embodiment, the structure of the surrounding edge 11 of the base 1 and the annular upper cover 5 are simplified, the distance between the plasma field at the edge of the wafer and the ground is increased, and the plasma energy density at the edge of the wafer is increased, thereby improving the uniformity of the film; at the same time, the expansion of the base 1 in the vertical direction is reduced, the height difference caused by thermal expansion is reduced, and the problems of high leakage current and high back helium leakage rate are improved.

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An electrostatic chuck, characterized in that: include: A base, a circular ring and a chuck body, wherein the circular ring is fixedly arranged on the upper surface of the base, the chuck body is installed in the circular ring, the upper surface of the chuck body is used to support the wafer, and the base is configured as a grounding end of the plasma; The upper surface of the base is a planar structure, and the outer side wall of the ring is flush with the outer side wall of the base, so that the plasma at the edge of the wafer is away from the ground end.

2. The electrostatic chuck according to claim 1, characterized in that: An outer ring positioning step is provided on the outer edge of the upper surface of the base, and a first inner ring positioning step is provided on the inner edge of the lower surface of the circular ring. The first inner ring positioning step is matched with the outer ring positioning step in a stepped manner.

3. The electrostatic chuck according to claim 2, characterized in that: The upper surface of the base and the lower surface of the circular ring form a fitting step interface, and the first inner ring positioning step protrudes downward from the step interface and cooperates with the outer ring positioning step.

4. The electrostatic chuck according to claim 1, characterized in that: The invention also comprises an isolation plate, which is installed in the circular ring and arranged between the chuck body and the base to isolate the chuck body and the base.

5. The electrostatic chuck according to claim 4, characterized in that: A second inner ring positioning step is provided on the inner side of the circular ring, and the side wall and the top wall of the isolation plate are respectively fitted and positioned with the second inner ring positioning step.

6. The electrostatic chuck according to claim 1, characterized in that: At least one layer of annular heat-insulating grooves is provided on the inner side of the circular ring, and a heat-insulating ring is provided in each of the heat-insulating grooves.

7. The electrostatic chuck according to claim 1, characterized in that: A chamfer is provided at the intersection and transition between the outer side wall of the ring and the top wall.

8. The electrostatic chuck according to any one of claims 1 to 7, characterized in that: The maximum outer diameter of the circular ring is the same as the maximum outer diameter of the base. The inner edge of the upper surface of the circular ring is provided with a boss for supporting the wafer, and the boss is lower than the upper surface of the chuck body.

9. The electrostatic chuck according to claim 8, characterized in that: A wafer positioning portion is provided on the outer peripheral side of the boss, and the height of the wafer positioning portion is higher than the height of the boss.

10. A thin film deposition device, characterized in that: Comprising an electrostatic chuck as described in any one of claims 1-9.

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