Chemical vapor deposition equipment

Abstract

The invention discloses chemical vapor deposition equipment, which is characterized in that a wafer tray, a gas inlet device, a heater, an upper liner and a flow limiting ring are arranged in a vacuum cavity of the chemical vapor deposition equipment, and the wafer tray, the upper liner and the flow limiting ring form a reaction area of the chemical vapor deposition equipment; the lower surface of the upper liner is provided with an annular protruding part, the protruding part is provided with an inner side face, a bottom face and an outer side face, the inner side wall of the current limiting ring is provided with a supporting part extending towards the direction of the wafer tray, the top face of the supporting part is attached to the bottom face of the protruding part, and the inner side wall located above the supporting part is attached to the outer side face of the protruding part. By changing the matching mode of the upper gasket and the flow limiting ring, the heating area of the edge area of the upper gasket can be enlarged and the temperature uniformity of the upper gasket can be optimized while the flow resistance of the binding surface is increased and process gas leakage is reduced. Therefore, the flow field uniformity and the temperature field uniformity in the vacuum cavity can be optimized at the same time by arranging the protruding part and the supporting part.

Description

Technical Field

[0001] The present invention relates to the field of chemical vapor deposition equipment, and particularly to a chemical vapor deposition equipment capable of simultaneously optimizing the uniformity of the flow field and the temperature field. Background Art

[0002] Chemical vapor deposition (CVD) process is a technology that introduces gases containing elements constituting the thin film and other gases required for the reaction into the reaction chamber, and chemical reactions occur on the substrate surface to form a thin film. The uniformity of thin film growth is a key index in the chemical vapor deposition process, and the main factors affecting this index include the uniformity of the temperature field and the uniformity of the flow field.

[0003] Generally, a chemical vapor deposition equipment defines a reaction area by an upper gasket, a wafer tray, and a flow-limiting ring arranged around the wafer tray, and a heater is provided below the wafer tray. However, the inventors found the following problems in the process: First, the upper gasket and the flow-limiting ring cannot be completely fitted and sealed, and there is a gap between them, which will cause air leakage from the reaction area to the outside and affect the uniformity of the flow field; Second, the upper gasket is mainly affected by the thermal radiation from the wafer tray, which will cause the middle area of the upper gasket to receive more radiation than the edge area, and the temperature of the edge area is much lower than that of the middle area. The excessive temperature difference will cause the upper gasket to rupture and affect the service life of the upper gasket; Third, in some processes that require in-situ cleaning, the too low temperature in the edge area of the upper gasket will also cause the deposits in the edge area to not be cleaned off.

[0004] It should be noted that the content of the above background art was discovered by the inventors during the process of realizing the invention, and it is an important part of the inventive concept of the present invention and does not constitute the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a chemical vapor deposition equipment to simultaneously optimize the uniformity of the flow field and the temperature field.

[0006] To achieve the above object, the present invention provides a chemical vapor deposition device, which includes a vacuum chamber. Inside the vacuum chamber, there are a wafer tray, a gas inlet device, a heater, an upper gasket, and a flow limiting ring. The upper gasket is disposed opposite to the wafer tray, and the flow limiting ring surrounds the wafer tray. The wafer tray, the upper gasket, and the flow limiting ring form the reaction area of the chemical vapor deposition device. The gas inlet device is used to supply process gas to the reaction area, and the heater is used to heat the wafer tray. The lower surface of the upper gasket is provided with an annular protrusion, which has an inner side surface, a bottom surface, and an outer side surface. The inner side wall of the flow limiting ring is provided with a support portion extending towards the wafer tray. The top surface of the support portion is in contact with the bottom surface of the protrusion, and the inner side wall above the support portion is in contact with the outer side surface of the protrusion.

[0007] Preferably, the side surface of the support portion is an inclined surface extending from the inner side wall of the flow limiting ring to the top surface of the support portion.

[0008] Preferably, the inner side surface of the flow limiting ring is a vertical plane.

[0009] Preferably, the inner side surface of the flow limiting ring is an inclined surface, and the slope of the inner side surface of the flow limiting ring is the same as the slope of the side surface of the support portion, and the two can be spliced into a continuous inclined surface.

[0010] Preferably, both the inner side surface of the flow limiting ring and the side surface of the support portion are curved surfaces, and the two can be spliced into a continuous concave curved surface.

[0011] Preferably, there is an air extraction hole inside the vacuum chamber, and the inner edge of the inner side surface of the protrusion is closer to the wafer tray than the inner edge of the air extraction hole.

[0012] Preferably, the surface area of the inner side surface of the protrusion is larger than the surface area of the top of the protrusion.

[0013] Preferably, both the bottom surface of the protrusion and the top surface of the support portion are horizontal planes, or both are inclined surfaces.

[0014] Preferably, the bottom surface of the protrusion includes a concave portion, and the top surface of the support portion includes a matching convex portion; or, the bottom surface of the protrusion includes a convex portion, and the top surface of the support portion includes a matching concave portion.

[0015] Preferably, there is a gap between the lower surface of the upper gasket and the top end surface of the flow limiting ring.

[0016] Preferably, an air extraction ring is also provided inside the vacuum chamber. The air extraction ring includes a top ring at the top; in the circumferential direction, a plurality of air extraction holes are formed in the top ring.

[0017] Preferably, the flow-limiting ring is supported by at least the air-extracting ring.

[0018] Preferably, a shielding ring is further included in the vacuum chamber and is disposed between the wafer tray and the air-extracting ring.

[0019] Preferably, the outer radial side of the shielding ring is supported by the air-extracting ring, and there is a gap between the inner radial side of the shielding ring and the wafer tray.

[0020] Preferably, a structure for fixing both is provided between the outer radial side of the shielding ring and the top ring.

[0021] Preferably, the material of the shielding ring is quartz or ceramic.

[0022] Preferably, an elastic element is further provided in the vacuum chamber. When the vacuum chamber is in a closed state, the elastic element provides a force to the air-extracting ring in a direction away from the bottom plate of the vacuum chamber.

[0023] Preferably, a plurality of hollow support columns are further provided in the vacuum chamber, and the air-extracting ring is supported by at least the support columns.

[0024] Preferably, the support column includes an extension portion extending radially outward and an elastic element located below the extension portion. When the vacuum chamber is in a closed state, the elastic element provides a force to the extension portion in a direction away from the bottom plate of the vacuum chamber.

[0025] Preferably, the diameter of the wafer tray is smaller than the diameter of the heater.

[0026] Preferably, the upper gasket is mounted on the top plate of the vacuum chamber.

[0027] Preferably, the gas inlet device is located at the center of the vacuum chamber, and the gas inlet device supplies process gas horizontally to the reaction area.

[0028] The beneficial effects of the present invention at least include:

[0029] (1) By providing the protruding portion and the supporting portion, the cooperation between the upper gasket and the flow-limiting ring is increased from one surface when the protruding portion and the supporting portion are not provided to multiple surfaces, increasing the flow resistance of the fitting surface between the upper gasket and the flow-limiting ring, reducing the leakage of process gas during the deposition process and the cleaning process, thereby ensuring the uniform distribution of the flow field in the reaction area and improving the film deposition quality and the cleaning effect of the vacuum chamber.

[0030] (2) While reducing the leakage of process gas, the temperature difference between the edge area and the central area is reduced, optimizing the temperature uniformity of the upper gasket. At the same time, it can also ensure that during in-situ cleaning, the cleaning gas can completely clean the deposits on the upper gasket, preventing residues from appearing. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of a chemical vapor deposition device in the prior art.

[0032] Figure 2 It is a schematic diagram of a chemical vapor deposition device proposed by the present invention.

[0033] Figure 3A It is a partial schematic diagram of the chemical vapor deposition device in Embodiment 1; Figure 3B It is Figure 3A a partial enlarged view of

[0034] Figure 4A It is a partial schematic diagram of the chemical vapor deposition device in Embodiment 2; Figure 4B It is Figure 4A a partial enlarged view of

[0035] In the figure, 10 - wafer tray; 11 - rotating shaft; 20 - upper gasket; 21 - protruding part; 211 - inner side; 212 - bottom surface; 213 - outer side; 30 - flow - limiting ring; 301 - inner side wall; 31 - supporting part; 311 - top surface; 312 - side surface; 40 - air - extraction ring; 401 - inner ring; 402 - outer ring; 403 - top ring; 50 - support column; 501 - extension part; 502 - elastic element; 60 - air - inlet device; 70 - shielding ring; 80 - heater; 90 - vacuum chamber. Detailed Embodiments

[0036] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection; it may be a direct connection, or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] It should be noted that, unless otherwise specified, the interior of the vacuum chamber of the chemical vapor deposition equipment has a rotationally symmetric structure.

[0040] As Figure 1 shown, in the prior art, the chemical vapor deposition equipment includes a wafer tray 10, an upper gasket 20 disposed opposite to the wafer tray 10, and a flow limiter ring 30 disposed around the wafer tray 10. A heater is further provided below the wafer tray 10 for heating the wafer tray to provide a suitable reaction temperature for the chemical vapor deposition process. Inside the vacuum chamber, the wafer tray 10, the upper gasket 20, and the flow limiter ring 30 define a reaction region. The upper gasket 20 can be installed on the top plate of the vacuum chamber, and when the equipment is opened, the upper gasket 20 moves with the opening and closing of the top plate. Currently, the bottom surface of the upper gasket 20 and the top surface of the flow limiter ring 30 are both planar structures. The inventor found during the process that the upper gasket 20 and the flow limiter ring 30 cannot be completely sealed in contact, and the gap between them will cause process gas leakage during the deposition process and cleaning gas leakage during the in-situ cleaning process, thereby affecting the film growth quality and the cleaning effect of the vacuum chamber.

[0041] The heat of the upper gasket 20 mainly comes from the thermal radiation of the wafer tray 10 ( Figure 1 the wavy line in represents thermal radiation and does not represent a physical component), however, the distance between the edge region of the upper gasket 20 and the wafer tray 10 is greater than the distance between the central region of the upper gasket 20 and the wafer tray 10, resulting in the temperature of the edge region being lower than that of the central region. During the process, the excessive temperature difference will cause the upper gasket 20 to crack. During the in-situ cleaning process, the too low temperature of the edge region of the upper gasket 20 will also cause the deposits in the edge region to not fully react with the cleaning gas, thus remaining on the upper gasket 20. In the subsequent deposition process, the residues may fall on the wafer, affecting the film growth quality.

[0042] To solve the problem of process gas leakage, the present invention first proposes a chemical vapor deposition equipment, as Figure 2As shown, within the vacuum chamber 90, the wafer tray 10, the upper gasket 20, and the current-limiting ring 30 form a reaction region. The materials of the upper gasket 20 and the current-limiting ring 30 can be graphite. The upper gasket 20 can be installed on the top plate of the vacuum chamber 90, for example, any connection method such as bolts can be used to fixedly install the upper gasket 20 to the top plate. In other embodiments, the upper gasket 20 may not be installed on the top plate of the vacuum chamber 90.

[0043] The wafer tray 10 is used to carry one or more wafers; preferably, a plurality of small trays for carrying wafers are distributed on the wafer tray 10, and the small trays can rotate under the drive of the air flow. The wafer tray 10 is supported by a rotating shaft 11, and the rotating shaft 11 can drive the wafer tray 10 to rotate.

[0044] A heater 80 is provided below the wafer tray 10. The heater 80 can be a radio frequency heater or a radiation heater. In other embodiments, the heater 80 can also be placed inside the wafer tray 10. Preferably, in order to compensate for the heat loss in the edge region of the wafer tray 10, the diameter of the wafer tray 10 is set to be smaller than the diameter of the heater 80.

[0045] The gas inlet device 60 is located in the center of the vacuum chamber 90. The gas inlet device 60 includes at least one nozzle inserted into the vacuum chamber 90, and the nozzle supplies process gas horizontally to the reaction region. A through hole can be provided in the central region of the upper gasket 20 to enable the installation of the gas inlet device 60, and the nozzle is located below the upper gasket 20.

[0046] In other embodiments, the gas inlet device 60 can adopt any other showerhead structure or other gas inlet structure in the prior art, such as a showerhead that supplies process gas in the vertical direction, as long as it can uniformly supply process gas to the wafer tray 10. The process gas supplied by the gas inlet device 60 is deposited into a film on the wafer, and the residual gas is discharged from the vacuum chamber 90 through the pumping ring 40. It should be noted that Figure 2 the arrows in only serve as a schematic of the approximate flow direction of some gases within the vacuum chamber 90.

[0047] The pumping ring 40 is a hollow ring structure, including an inner ring 401, an outer ring 402, and a top ring 403 connecting the inner ring 401 and the outer ring 402. In the circumferential direction, a plurality of pumping holes are provided on the top ring, which are uniformly or non-uniformly distributed.

[0048] The chemical vapor deposition equipment further includes a shielding ring 70 disposed between the radial outer side of the wafer tray 10 and the pumping ring 40. The lower surface of the radial outer side of the shielding ring 70 contacts the upper surface of the radial inner side of the top ring 403 to support the shielding ring 70. There is a gap (not shown) between the radial inner side of the shielding ring 70 and the wafer tray 10. Without affecting the rotation of the wafer tray 10, the shielding ring 70 can effectively block some process gases from entering the non-reaction area below the wafer tray 10, preventing the process gases from forming deposits on the lower surface of the wafer tray 10, the heater 80, the rotating shaft 11, and other components in the non-reaction area. In addition, the shielding ring 70 can be made of materials with low thermal conductivity such as quartz or ceramic, which can play a heat preservation effect and reduce the heat conduction of the wafer tray 10 outside the reaction area.

[0049] Optionally, a structure for fixing the shielding ring 70 and the pumping ring 40 is provided between them. For example, a protrusion is provided on the lower surface of the radial outer side of the shielding ring 70, and a mating groove is provided on the upper surface of the radial inner side of the top ring 403. The protrusion is placed in the groove to better fix the shielding ring 70. It should be understood that the protrusion can also be provided on the radial inner surface of the top ring 403, and the mating groove can be provided on the lower surface of the radial outer side of the shielding ring 70. Among them, the protrusion and the groove can be multiple separated components distributed circumferentially, or a continuous annular one.

[0050] The pumping ring 40 is also used to support the flow-limiting ring 30, as Figure 2 shown, the bottom end of the flow-limiting ring 30 is supported by the upper surface of the radial outer side of the top ring 403. Optionally, a structure for fixing the top ring 403 and the flow-limiting ring 30 is provided between them. For example, a recess is provided on the upper surface of the radial outer side of the top ring 403, and the bottom end of the flow-limiting ring 30 is disposed in the recess.

[0051] The chemical vapor deposition equipment further includes an elastic element 502 for applying a force to the air extraction ring 40 in a direction away from the bottom plate of the vacuum chamber 90. In one embodiment, the air extraction ring 40 is supported by a hollow support column 50, and a plurality of support columns 50 can be evenly distributed along the circumference of the vacuum chamber 90. The bottom end of the support column 50 extends at least to the bottom plate of the vacuum chamber 90 and is connected to an air extraction device (not shown). The support column 50 includes an extension portion 501 extending radially outward, and the elastic element 502 is located below the extension portion 501. As an example, the elastic element 502 is a spring. When the vacuum chamber 90 is in a closed state, the elastic element 502 is in a compressed state, so as to provide a thrust in a direction away from the bottom plate of the vacuum chamber 90. The upward thrust can make the upper gasket 20 and the flow limiting ring 30 fit better, enhance the sealing effect, and optimize the flow field uniformity. In another embodiment, the inner ring 401 and the outer ring 402 can be set to extend at least to the bottom plate of the vacuum chamber 90, and a step portion is provided on the outer side wall of the inner ring and / or the outer ring, and the elastic element 502 is placed between the step portion and the bottom plate of the vacuum chamber 90.

[0052] In one embodiment, one end of the elastic element 502 is connected to the extension portion 501, and the other end is connected to the bottom plate of the vacuum chamber 90. In other embodiments, one end of the elastic element 502 is connected to the extension portion 501, and the other end can be connected to any other fixed component, as long as the elastic element 502 can provide a thrust in a direction away from the bottom plate of the vacuum chamber 90 when it is in a compressed state.

[0053] However, the inventor found during the experiment that the flexible connection method of adding the elastic element 502 is still not sufficient to completely eliminate the gap between the upper gasket 20 and the flow limiting ring 30. At the same time, it cannot solve the problem that the temperature of the edge region of the upper gasket 20 is lower than that of the central region. It is worth mentioning that the discovery of this problem is the key to the present invention. This problem does not belong to the problems known or easily thought of by those skilled in the art, but can only be discovered during the practice process.

[0054] Therefore, the inventor further developed the chemical vapor deposition equipment as described in Embodiments 1 and 2 below, where the parts identical to the Figure 2 chemical vapor deposition equipment shown are not described in detail.

[0055] Embodiment 1

[0056] To solve the above problems, as shown in Figure 3A and Figure 3BAs shown, an annular protrusion 21 is provided on the lower surface of the upper gasket 20. The vertical cross-section of the protrusion 21 is generally rectangular. The protrusion 21 has an inner side surface 211, a bottom surface 212, and an outer side surface 213. A support portion 31 extending toward the wafer tray 10 is provided on the inner side wall 301 of the flow-limiting ring 30. The top surface 311 of the support portion 31 is in contact with the bottom surface 212 of the protrusion 21. The inner side wall 301 of the flow-limiting ring 30 above the support portion 31 is in contact with the outer side surface 213 of the protrusion 21. The inner side surface 211 of the protrusion 21 is located on the innermost side and is in contact with the process gas.

[0057] The vertical cross-section of the support portion 31 is generally triangular. The side surface 312 of the support portion 31 is an inclined surface extending from the inner side wall 301 to the top surface 311. The inclined surface is beneficial for guiding the gas in the vacuum chamber 90 to flow toward the pumping ring 40.

[0058] In this embodiment, an elastic element 502 is included. When the vacuum chamber 90 is in a closed state, the upward thrust generated by the elastic element 502 in a compressed state can make the upper gasket 20 and the flow-limiting ring 30 fit better, enhance the sealing effect, and optimize the flow field uniformity. It should be noted that in some embodiments, the elastic element 502 may not be provided, that is, the flow-limiting ring 30 is supported by the pumping ring 40, and the pumping ring 40 is supported by the support column 50. In some embodiments, the flow-limiting ring 30 may also be arranged not to be supported by the pumping ring 40. For example, the flow-limiting ring 30 may be fixed to the side plate of the vacuum chamber 90.

[0059] By providing the protrusion 21 and the support portion 31, the cooperation between the upper gasket 20 and the flow-limiting ring 30 is increased from one surface when the protrusion 21 and the support portion 31 are not provided to two surfaces, increasing the flow resistance of the fitting surface between the upper gasket 20 and the flow-limiting ring 30, reducing the leakage of process gas during the deposition process and the cleaning process, thereby ensuring the uniform distribution of the flow field in the reaction area and improving the thin film deposition quality and the cleaning effect of the vacuum chamber.

[0060] While reducing the leakage of process gas, since the protrusion 21 extends from the lower surface of the upper gasket 20 toward the wafer tray 10, the protrusion 21 is closer to the wafer tray 10 and the heater 80 and can receive more thermal radiation. The heat received by the protrusion 21 will be conducted to the edge area of the upper gasket 20, thereby increasing the temperature of the edge area, reducing the temperature difference between the edge area and the central area, and optimizing the temperature uniformity of the upper gasket 20. At the same time, it can also ensure that during in-situ cleaning, the cleaning gas can completely clean the deposits on the upper gasket 20 and prevent residues from appearing.

[0061] Preferably, in this embodiment, the surface area of the inner side surface 211 of the protruding portion 21 is larger than the surface area of the top of the protruding portion 21 (the top is in the same plane as the lower surface of the upper gasket 20). Then, compared with the upper gasket without the protruding portion 21, the upper gasket 20 provided with the protruding portion 21 has a larger heat-receiving area, which can further optimize the temperature uniformity of the upper gasket 20.

[0062] Preferably, there may be a gap S between the lower surface of the upper gasket 20 and the top end surface of the current-limiting ring 30, and the gap S can reserve space for the thermal expansion of the upper gasket 20 and the current-limiting ring 30 during the process.

[0063] Embodiment 2

[0064] As Figure 4A and Figure 4B shown, an annular protruding portion 21 is provided on the lower surface of the upper gasket 20. The vertical cross-section of the protruding portion 21 is generally trapezoidal. The protruding portion 21 has an inner side surface 211, a bottom surface 212, and an outer side surface 213, where the inner side surface 211 is an inclined surface. A support portion 31 extending in the direction of the wafer tray 10 is provided on the inner side wall 301 of the current-limiting ring 30. The top surface 311 of the support portion 31 is in contact with the bottom surface 212 of the protruding portion 21. The inner side wall 301 of the current-limiting ring 30 above the support portion 31 is in contact with the outer side surface 213 of the protruding portion 21. The inner side surface 211 of the protruding portion 21 is located at the innermost and is in contact with the process gas.

[0065] The vertical cross-section of the support portion 31 is generally triangular. The side surface 312 of the support portion 31 is an inclined surface extending from the inner side wall 301 to the top surface 311, and the slopes of the side surface 312 and the inner side surface 211 are approximately the same. After the support portion 31 and the upper gasket 20 are in contact, the side surface 312 and the inner side surface 211 can be spliced into a continuous inclined surface. Compared with Embodiment 1, Embodiment 2 is more conducive to realizing the smooth transition of the process gas and making the flow field more stable. Preferably, as Figure 4A shown, the inner edge A of the inner side surface 211 is closer to the wafer tray 10 than the inner edge B of the air extraction holes of the air extraction ring 40, so as to better guide the gas in the vacuum chamber 90 to flow to the air extraction ring 40. In other embodiments, both the inner side surface 211 and the side surface 312 can be curved surfaces, and the two are spliced into a continuous concave curved surface.

[0066] In this embodiment, an elastic element 502 is included. When the vacuum chamber 90 is in a closed state, the upward thrust generated by the elastic element 502 in a compressed state can prompt the upper gasket 20 and the flow-limiting ring 30 to fit better, enhance the sealing effect, and optimize the flow field uniformity. It should be noted that in some embodiments, the elastic element 502 may not be provided, that is, the flow-limiting ring 30 is supported by the air extraction ring 40, and the air extraction ring 40 is supported by the support column 50. In some embodiments, the flow-limiting ring 30 may also be arranged not to be supported by the air extraction ring 40. For example, the flow-limiting ring 30 can be fixed to the side plate of the vacuum chamber 90.

[0067] By providing the protrusion 21 and the support portion 31, the flow resistance of the fitting surface between the upper gasket 20 and the flow-limiting ring 30 is increased, and the leakage of process gas during the deposition process and the cleaning process is reduced, thereby improving the thin film deposition quality and the cleaning effect of the vacuum chamber.

[0068] While reducing the leakage of process gas, the protrusion 21 extending in the direction close to the wafer tray 10 can receive more thermal radiation, increase the temperature of the edge region, and reduce the temperature difference between the edge region and the central region. At the same time, it can also ensure that during in-situ cleaning, the cleaning gas can completely clean the deposits on the upper gasket 20 to prevent residues.

[0069] Preferably, in this embodiment, the surface area of the inner side surface 211 of the protrusion 21 is larger than the surface area of the top of the protrusion 21 (the top is in the same plane as the lower surface of the upper gasket 20). Compared with Embodiment 1, the surface area of the inner side surface 211 in Embodiment 2 can be larger, so it can have a larger heat-receiving area and can further optimize the temperature uniformity of the upper gasket 20. Preferably, in this embodiment, the surface area of the inner side surface 211 of the protrusion 21 is larger than the surface area of the bottom surface 212.

[0070] Preferably, there may be a gap S between the lower surface of the upper gasket 20 and the top end surface of the flow-limiting ring 30, and the gap S can reserve space for the thermal expansion of the upper gasket 20 and the flow-limiting ring 30 during the process.

[0071] It should be understood that although in Embodiments 1 and 2, the bottom surface 212 and the top surface 311 are both substantially horizontal planes, in some embodiments, the bottom surface 212 and the top surface 311 can both adopt inclined surfaces, as long as it can ensure the fitting of the bottom surface 212 and the top surface 311, and the fitting of the outer side surface 213 and the inner side wall 301. In some other embodiments, the bottom surface 212 may further include concave or convex portions, and correspondingly, the top surface 311 includes matching convex or concave portions to further increase the flow resistance between the fitting surfaces of the upper gasket 20 and the flow-limiting ring 30.

[0072] It should be noted that if the processing precision of the upper gasket 20 including the protruding portion 21 and the flow-limiting ring 30 including the supporting portion 31 is high enough, and during the process, the thermal expansion amounts of the upper gasket 20 and the flow-limiting ring 30 are small enough, the fitting of the inner side wall 301 and the outer side surface 213 can be set to the state where they are in contact at normal temperature (for example, 25°C). Then, at normal temperature and the process temperature, the inner side wall 301 and the outer side surface 213 are both in a contacting state. If the processing precision of the upper gasket 20 including the protruding portion 21 and the flow-limiting ring 30 including the supporting portion 31 is limited, or during a high-temperature process (for example, the process temperature exceeds 800°C, or exceeds 1000°C, or exceeds 1200°C), when the thermal expansion amounts of the upper gasket 20 and the flow-limiting ring 30 are relatively large, the fitting of the inner side wall 301 and the outer side surface 213 can be set to have a gap of less than 1 mm between them at normal temperature, as long as they can be in contact during the process. Preferably, the gap is 0.1 mm - 0.5 mm. That is, in the present invention, the fitting of the inner side wall 301 and the outer side surface 213 means that they are in a contacting state during the process.

[0073] In summary, the present invention provides a chemical vapor deposition device. By adding the protruding portion 21 to the upper gasket 20 and arranging the supporting portion 31 on the inner side wall 301 of the flow-limiting ring 30, the cooperation mode between the upper gasket 20 and the flow-limiting ring 30 is changed. It can increase the flow resistance of the contact surface between the upper gasket 20 and the flow-limiting ring 30 and reduce the leakage of process gas, while expanding the heat-receiving area of the edge region of the upper gasket 20 and optimizing the temperature uniformity of the upper gasket 20. Therefore, by arranging the protruding portion 21 and the supporting portion 31, the flow field uniformity and the temperature field uniformity in the vacuum chamber can be optimized simultaneously.

[0074] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation to the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A chemical vapor deposition device, characterized in that, The chemical vapor deposition equipment includes a vacuum chamber, in which a wafer tray, a gas inlet device, a heater, an upper gasket and a flow limiting ring are provided. The upper gasket is disposed opposite to the wafer tray, and the flow limiting ring surrounds the wafer tray. The wafer tray, the upper gasket and the flow limiting ring form the reaction area of the chemical vapor deposition equipment; The gas inlet device is used to supply process gas to the reaction area, and the heater is used to heat the wafer tray; The lower surface of the upper gasket is provided with an annular protruding portion, which has an inner side surface, a bottom surface, and an outer side surface. The inner side wall of the flow limiting ring is provided with a supporting portion extending towards the wafer tray. The top surface of the supporting portion is attached to the bottom surface of the protruding portion, and the inner side wall above the supporting portion is attached to the outer side surface of the protruding portion.

2. The chemical vapor deposition device according to claim 1, characterized in that, The side surface of the supporting portion is an inclined surface extending from the inner side wall of the flow limiting ring to the top surface of the supporting portion.

3. The chemical vapor deposition device according to claim 2, characterized in that, The inner side surface of the flow limiting ring is a vertical plane.

4. The chemical vapor deposition device according to claim 2, characterized in that, The inner side surface of the flow limiting ring is an inclined surface, and the slope of the inner side surface of the flow limiting ring is the same as that of the side surface of the supporting portion, and the two can be spliced into a continuous inclined surface.

5. The chemical vapor deposition device according to claim 1, characterized in that, Both the inner side surface of the flow limiting ring and the side surface of the supporting portion are curved surfaces, and the two can be spliced into a continuous concave curved surface.

6. The chemical vapor deposition device according to claim 4 or 5, characterized in that, There is an air extraction hole in the vacuum chamber, and the inner edge of the inner side surface of the protruding portion is closer to the wafer tray than the inner edge of the air extraction hole.

7. The chemical vapor deposition device according to claim 1, characterized in that, The surface area of the inner side surface of the protruding portion is larger than the surface area of the top of the protruding portion.

8. The chemical vapor deposition device according to claim 1, characterized in that, Both the bottom surface of the protruding portion and the top surface of the supporting portion are horizontal planes, or both are inclined surfaces.

9. The chemical vapor deposition device according to claim 1, characterized in that, The bottom surface of the protruding portion includes a concave portion, and the top surface of the supporting portion includes a matching convex portion; or, the bottom surface of the protruding portion includes a convex portion, and the top surface of the supporting portion includes a matching concave portion.

10. The chemical vapor deposition device according to claim 1, characterized in that, There is a gap between the lower surface of the upper gasket and the top end surface of the flow limiting ring.

11. The chemical vapor deposition device according to claim 1, characterized in that, There is also an air extraction ring in the vacuum chamber, and the air extraction ring includes a top ring at the top; in the circumferential direction, a plurality of air extraction holes are formed in the top ring.

12. The chemical vapor deposition device according to claim 11, characterized in that, The flow limiting ring is at least supported by the air extraction ring.

13. The chemical vapor deposition device according to claim 11, characterized in that, The vacuum chamber also includes a shielding ring disposed between the wafer tray and the air extraction ring.

14. The chemical vapor deposition device according to claim 13, characterized in that, The radially outer side of the shielding ring is supported by the air extraction ring, and there is a gap between the radially inner side of the shielding ring and the wafer tray.

15. The chemical vapor deposition device according to claim 14, characterized in that, There is a structure for fixing the two between the radially outer side of the shielding ring and the top ring.

16. The chemical vapor deposition device according to claim 13, characterized in that, The material of the shielding ring is quartz or ceramic.

17. The chemical vapor deposition device according to claim 12, characterized in that, There is also an elastic element in the vacuum chamber. When the vacuum chamber is in a closed state, the elastic element provides a force to the air extraction ring in the direction away from the bottom plate of the vacuum chamber.

18. The chemical vapor deposition device according to claim 12, characterized in that, There are also a plurality of hollow support columns in the vacuum chamber, and the air extraction ring is at least supported by the support columns.

19. The chemical vapor deposition apparatus according to claim 18, wherein, The support column includes an extension portion extending radially outwards and an elastic element located below the extension portion. When the vacuum chamber is in a closed state, the elastic element provides a force to the extension portion in the direction away from the bottom plate of the vacuum chamber.

20. The chemical vapor deposition apparatus according to claim 1, wherein, The diameter of the wafer tray is smaller than the diameter of the heater.

21. The chemical vapor deposition apparatus according to claim 1, wherein, The upper gasket is installed on the top plate of the vacuum chamber.

22. The chemical vapor deposition apparatus according to claim 1, wherein, The intake device is located in the center of the vacuum chamber, and the intake device supplies process gas to the reaction area laterally.

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