Exhaust shield ring and reaction chamber structure

Abstract

The present application belongs to the field of plasma processing in the field of semiconductor manufacturing, and provides an exhaust shield ring and a reaction chamber structure, which are used in a reaction chamber structure of a plasma processing device. The exhaust shield ring comprises an inner circumference and an outer circumference extending outwards from the inner circumference by a preset width, the inner diameter of the inner circumference being less than the diameter of a wafer to be processed of the plasma processing device, and the outer diameter of the inner circumference being greater than or equal to the diameter of said wafer; the inner circumference is used for shielding an edge region of said wafer; a plurality of vent holes for discharging a reaction gas out of the reaction chamber structure are provided on the outer circumference. The exhaust shield ring of the present application reduces the risk of surface contamination of wafers within the reaction chamber structure.

Description

Shielding exhaust ring and reaction chamber structure

[0001] This application claims priority to Chinese Patent Application No. 202411356693.8, filed September 26, 2024, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present application relates to a plasma processing device in the field of semiconductor manufacturing, in particular to a shielding exhaust ring and reaction chamber structure. BACKGROUND

[0003] Plasma chemical vapor deposition (PECVD) equipment is used to deposit insulating films, protective films, oxide films, metal films, etc. on wafers using chemical reactions of gases in a vacuum state in semiconductor manufacturing processes.

[0004] In the reaction chamber of a thin film deposition device, one source of wafer surface contamination is the peeling or falling off of material deposited on the edge or back of the wafer during the thin film deposition process during the process. In the prior art, the edge portion of the wafer is generally shielded by a shielding ring to prevent the deposition of thin films on the edge or back of the wafer. The shielding ring is often combined with a vertical vent ring for controlling the pressure and gas flow in the reaction chamber and is disposed in the chamber. The shielding ring is located at the outer periphery of the vertical vent ring, and the direction of the vent holes on the vertical vent ring is perpendicular to the wafer plane. Contaminants accumulated near the vent holes and crystals at the joint of the assembly can contaminate the wafer.

[0005] In the chamber of a thin film deposition device, how to reduce the risk of contamination caused by material peeling or falling onto the wafer surface is a technical problem that needs to be solved in the field. SUMMARY

[0006] To solve the problems in the prior art, the present application provides a shielding exhaust ring and reaction chamber structure.

[0007] The present application provides a shielding exhaust ring applied in a reaction chamber structure of a plasma processing device, comprising an inner ring circumference and an outer ring circumference extending outward from the inner ring circumference by a predetermined width, the inner diameter of the inner ring circumference is smaller than the diameter of a wafer to be processed of the plasma processing device and the outer diameter of the inner ring circumference is greater than or equal to the diameter of the wafer, the inner ring circumference is used to shield the edge area of the wafer, and a plurality of vent holes are provided on the outer ring circumference for exhausting reaction gas in the reaction chamber structure.

[0008] According to the shielding exhaust ring provided by the present application, the height of the inner ring circumference is higher than the height of the outer ring circumference, and the inner ring circumference and the outer ring circumference are connected by a circumferentially arranged connecting surface.

[0009] According to the shielding exhaust ring provided by the application, the outer diameter of the inner ring is greater than or equal to the diameter of the heating table of the reaction cavity structure.

[0010] According to the shielding exhaust ring provided by the application, the lower surface of the outer ring is provided with at least two limiting grooves.

[0011] According to the shielding exhaust ring provided by the application, each of the air holes is arranged in a vertical direction and is uniformly distributed on the outer ring.

[0012] According to the shielding exhaust ring provided by the application, the preset width is the distance between the edge of the heating table and the inner wall of the reaction cavity structure.

[0013] The application further provides a reaction cavity structure, comprising:

[0014] a spraying plate arranged at the upper portion of the reaction cavity structure;

[0015] a heating table arranged below the spraying plate and used for placing a wafer;

[0016] a lifting structure used for driving the heating table to lift between a starting position and a process position;

[0017] The shielding exhaust ring according to any one of the above, wherein the inner ring of the shielding exhaust ring is placed on the heating table to shield the edge area of the wafer, and the outer ring of the shielding exhaust ring is arranged between the heating table and the inner wall of the reaction cavity to discharge the reaction gas in the reaction cavity structure through the air holes on the outer ring.

[0018] According to the reaction cavity structure provided by the application, the inner wall of the reaction cavity structure is provided with a bearing portion protruding inward, the bearing portion is higher than the starting position of the heating table and lower than the process position of the heating table, and the inner diameter of the bearing portion is smaller than the outer diameter of the outer ring.

[0019] According to the reaction cavity structure provided by the application, the bearing surface of the annular boss is provided with the same number of upward protrusions as the limiting grooves, the positions of the protrusions are arranged correspondingly to the limiting grooves, and the protrusions are used for being combined with the limiting grooves to fix the shielding exhaust ring.

[0020] According to the reaction cavity structure provided by the application, the height difference between the inner ring and the outer ring of the shielding exhaust ring is less than or equal to the thickness of the heating table.

[0021] According to the reaction cavity structure provided by the application, the bearing portion is an annular boss protruding inward from the inner wall of the reaction cavity structure.

[0022] According to the reaction cavity structure provided in the application, the supporting part is composed of a plurality of bosses protruding inward from the inner wall of the reaction cavity structure.

[0023] The shielding exhaust ring provided in the application is a whole ring structure, including an inner ring circumference and an outer ring circumference extending outward by a preset width, and the outer ring circumference is uniformly and spacedly provided with air holes, the inner diameter of the inner ring circumference is smaller than the diameter of the wafer, and the outer diameter of the inner ring circumference is greater than or equal to the diameter of the wafer, the edge of the wafer is shielded by the inner ring circumference of the shielding exhaust ring, and the reaction gas in the reaction cavity is discharged through the air holes provided in the outer ring circumference. Through the setting of the whole piece, the crystal peeling off the wafer surface caused by the gap between the combined pieces is avoided. Further, the air holes are provided on the outer ring circumference away from the wafer plane, avoiding the pollution of the wafer surface caused by the peeling of the crystal near the air holes. The shielding exhaust ring of the application simultaneously realizes the shielding of the wafer edge and the exhaust of the reaction cavity structure, and reduces the risk of wafer surface pollution in the reaction cavity.

[0024] SUMMARY

[0025] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Fig. 1 is a schematic diagram of the overall structure of the shielding exhaust ring provided in the application;

[0027] Fig. 2 is a top view of the shielding exhaust ring provided in the application;

[0028] Fig. 3 is a partial side sectional view of the reaction cavity structure provided in the application;

[0029] Fig. 4 is a partial enlarged view of the reaction cavity structure provided in the application;

[0030] Fig. 5 is a partial enlarged view of the shielding exhaust ring provided in the application;

[0031] Fig. 6a is a side sectional view of the reaction cavity structure provided in the application;

[0032] Fig. 6b is a side sectional view of the reaction cavity structure provided in the application;

[0033] Fig. 7 is a schematic diagram of the structure of the reaction cavity structure provided in the application.

[0034] Preferred embodiments of the application

[0035] In order to make the purposes, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below in conjunction with the accompanying drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0036] Referring to FIGS. 1-7, the embodiments of the present application provide a shielding exhaust ring and a reaction cavity structure.

[0037] The shielding exhaust ring of the embodiments of the present application is arranged in the reaction cavity structure of a PECVD device and acts in the process of adjusting the position of a wafer on a heating table in the reaction cavity structure.

[0038] Referring to FIGS. 1-2, specifically, the shielding exhaust ring of the embodiments of the present application is an integrated ring structure. The shielding exhaust ring 101 of the embodiments of the present application includes an inner ring circumference 102 and an outer ring circumference 103 extending outward from the inner ring circumference 102 by a certain width, as shown by the dashed line in FIG. 2, which is the boundary between the inner ring circumference 102 and the outer ring circumference 103. In the embodiments of the present application, the distance between the inner diameter of the inner ring circumference and the outer diameter of the outer ring circumference can be 45-46.25 mm, which is suitable for the corresponding PECVD device.

[0039] The inner diameter of the inner ring circumference 102 of the shielding exhaust ring 101 is smaller than the diameter of the wafer placed on the heating table, and the outer diameter of the inner ring circumference 102 is greater than or equal to the diameter of the wafer, so that the inner ring circumference 102 of the shielding exhaust ring 101 can cover the edge area of the wafer, avoiding the deposition of materials on the edge or back of the wafer during the thin film deposition process, thereby avoiding the peeling or falling of the deposited materials at these positions during the process.

[0040] Generally, in order to pursue a larger wafer usable area, the edge shielding area of the wafer tends to be smaller as much as possible in the case of implementation. In the embodiments, the edge shielding area can be in the range of 1-1.25 mm from the edge of the wafer. In specific implementation, the wafer is placed on the heating table in the reaction cavity structure and is placed concentrically below and with the shielding exhaust ring 101.

[0041] As shown in FIG. 3, the shielding exhaust ring 101 has a certain thickness, which is determined according to the specific PECVD equipment and is not limited here. In the vertical direction, the height of the inner ring circumference 102 is higher than that of the outer ring circumference 103, and the inner ring circumference 102 and the outer ring circumference 103 are connected by a circle of inclined surfaces 104 arranged along the circumference. Before the process starts or after the process ends, the heating table 202 will be adjusted to rise or fall accordingly. Therefore, the inner diameter of the inner ring circumference 102 is smaller than the diameter of the heating table 202, and the outer diameter of the inner ring circumference 102 is greater than or equal to the diameter of the heating table 202, so that the inner ring circumference 102 of the shielding exhaust ring overlaps the edge part of the heating table 202, and the shielding exhaust ring 101 is driven to move up and down by the support of the heating table 202.

[0042] Referring again to FIG. 2, a plurality of air holes 105 are uniformly and spacedly arranged on the outer ring circumference 103 of the shielding exhaust ring. The arrangement direction of the air holes 105 is the vertical direction, that is, perpendicular to the wafer horizontal plane. When the thin film deposition process is carried out in the cavity structure, the air holes 105 provide multiple airflow channels for the cavity, and the reaction gas in the cavity structure can be discharged from the cavity through each air hole 105. The uniformly and spacedly arranged air holes 105 ensure the stability of the air pressure and the balance of the airflow in the cavity structure.

[0043] Referring to FIG. 1, at least two limiting grooves 106 are further arranged on the lower surface of the outer ring circumference 103 of the shielding exhaust ring, and the limiting grooves 106 are uniformly distributed on the outer ring circumference 103.

[0044] As shown in FIGS. 3 and 4, a fixed annular boss 203 is arranged on the inner wall of the reaction cavity structure 201, and the annular boss 203 is inwardly protruding from the inner wall of the reaction cavity structure, so that the cross-sectional view of the reaction cavity structure 201 is an "L" type structure. At least two protruding protrusions 204 are arranged on the bearing surface of the annular boss 203 of the inner wall of the reaction cavity structure. It should be noted that the number of protrusions 204 corresponds to the number of limiting grooves 106 on the shielding exhaust ring 101, and the positions of the protrusions 204 correspond to the positions of the limiting grooves 106 on the shielding exhaust ring 101. In the initial state or after the process ends, the shielding exhaust ring 101 is placed on the annular boss 203 of the inner wall of the cavity of the reaction cavity structure 201, and the protrusions 204 on the bearing surface of the annular boss 203 are respectively embedded in the corresponding limiting grooves 106 of the outer ring circumference 103 of the shielding exhaust ring 101, so as to realize the fixation and alignment of the shielding exhaust ring 101.

[0045] In another embodiment, the inner wall of the reaction cavity structure is provided with a plurality of protrusions inwardly protruding for supporting the shielding vent ring 101 when the heating platform is in the initial state or after the process is completed. Therefore, the number of protrusions needs to correspond to the number of limiting grooves 106 of the shielding vent ring 101, and the setting positions of the protrusions also correspond to the positions of the limiting grooves 106. Further, a protrusion is arranged on the supporting surface of each protrusion to achieve the supporting and aligning of the shielding vent ring 101.

[0046] The above-mentioned annular protrusion and the plurality of protrusions are supporting portions arranged on the inner wall of the reaction cavity structure, and the fixing and aligning of the shielding vent ring are achieved based on the fitting of the protrusions on the supporting surface of the supporting portions and the limiting grooves on the shielding vent ring.

[0047] In a specific implementation, the shape of the vent hole can be a rounded rectangle as shown in FIG. 2, or can be a circle or an ellipse, which is not specifically limited here. The shape of the limiting groove 106 and the protrusion 204 on the supporting surface of the annular protrusion 203 needs to be fitted correspondingly. Referring to FIGS. 4 and 5, in the embodiment of the present application, the limiting groove 106 and the protrusion 204 can be a rectangular limiting groove 106 and a corresponding rectangular protrusion 204 as shown in the figures.

[0048] It needs to be further explained that the position of the annular protrusion 203 of the inner wall of the reaction cavity structure 201 is higher than the initial position of the heating platform 202 and lower than the process position of the heating platform 202. In the embodiment of the present application, the initial position refers to the position of the heating platform 202 when the wafer is not placed on the heating platform 202 and after the wafer is removed after the process is completed. The process position refers to the position of the heating platform when the wafer is placed on the heating platform and the heating platform is raised to a certain distance from the spray plate 205 (see FIG. 6b) in the reaction cavity structure. For example, the distance of 8mm-15mm can be regarded as the process position that reaches the process condition.

[0049] FIG. 6a is one of the side sectional views of the reaction cavity structure provided by the present application, as shown in FIG. 6a, when the heating platform 202 is in the initial position, i.e., the wafer is in the initial state or the process is completed.

[0050] In the reaction cavity structure 201, the shielding vent ring 101 is placed on the annular protrusion 203 of the inner wall of the cavity, and the fixing and aligning of the shielding vent ring 101 are achieved through the mutual fitting of the limiting groove 106 (see FIG. 1) and the protrusion 204 (see FIG. 4) on the supporting surface of the annular protrusion 203 (see FIG. 3).

[0051] In the initial state and the end state of the process, the heating table 202 in the reaction cavity structure 201 is located at a lower position of the reaction cavity, below the annular boss 203 in the reaction cavity structure 201, and the outer ring 103 of the shielding vent ring 101 is placed on the annular boss 203, and the inner ring 102 is not in contact with other structures. In the initial state and the end state of the process, the wafer to be processed can be placed on the heating table 202 or the wafer after the process is completed can be removed.

[0052] During the lifting of the heating table 202, after the heating table 202 contacts the inner ring 102 of the shielding vent ring 101 placed on the supporting surface of the annular boss 203, the heating table 202 will lift the shielding vent ring 101 away from the annular boss 203, so that the shielding vent ring 101 is lapped on the edge portion of the heating table 202 and moves upward together with the heating table 202 until reaching the process position, and the inner ring 102 of the shielding vent ring 101 can shield the edge of the wafer during the process.

[0053] Fig. 6b is a side sectional view of the reaction cavity structure provided by the present application, as shown in Fig. 6b, the heating table 202 is in the process position.

[0054] When the heating table 202 is in the process position, the shielding vent ring 101 is lapped on the edge of the heating table 202, and the inner ring 102 of the shielding vent ring 101 is supported by the heating table 202. In this case, since the inner diameter of the shielding vent ring 101 is smaller than the diameter of the wafer, and the outer diameter of the inner ring 102 is greater than or equal to the diameter of the wafer, the shielding vent ring 101 can cover the edge area of the wafer, and since the shielding vent ring 101 itself has a certain thickness and the inner ring 102 is lapped on the edge of the heating table 202, the shielding vent ring 101 is located about 3-5 mm above the wafer square, which does not affect the surface of the wafer. At the same time, the height difference between the inner ring 102 and the outer ring 103 of the shielding vent ring 101 is less than or equal to the thickness of the heating table 202, so that during the process, with the lifting of the heating table 202, the outer ring 103 of the shielding vent ring 101 always remains between the outer peripheral surface of the heating table 202 and the cavity wall, which divides the cavity into a first space 206 including the upper surface of the heating table 202 and the shower plate 205 and a second space 207 including the exhaust port of the reaction cavity structure (usually located at the bottom of the cavity). When the shielding vent ring 101 is placed on the heating table, the space between the outer ring of the heating table and the cavity wall is blocked by the shielding vent ring, which can prevent the falling of the peeled material into the second space 207 to damage other components.

[0055] After the process in the reaction cavity structure 201 is completed, the heating platform 202 falls back and is adjusted downward, and when the heating platform 202 passes through the annular boss 203 inside the cavity, the outer ring 103 of the shielding vent ring 101 is re-lapped on the annular boss 203, and the protrusions 204 on the annular boss supporting surface are embedded in the corresponding limiting grooves 106 on the shielding vent ring 101, so as to fix and align the shielding vent ring 101. Then the heating platform 202 continues to fall back to the starting position.

[0056] During the process in the reaction cavity structure, the cavity is pumped by a pump (not shown in the figure) outside the reaction cavity structure to maintain the stability of the airflow and air pressure in the cavity, and the gas in the cavity is discharged through the airflow channel formed by the vent holes 105 on the outer ring 103 of the shielding vent ring 101.

[0057] Since the vent holes 105 on the shielding vent ring 101 are arranged on the outer ring 103 of the shielding vent ring 101 away from the wafer plane, the peeling-off material formed near the vent holes 105 is also away from the wafer plane, which avoids contaminating the wafer. And since the vent holes 105 are uniformly and spacedly arranged, the uniformity of the airflow in the cavity is also ensured, which improves the uniformity of the film formed on the wafer surface during the film deposition process in the reaction cavity structure.

[0058] The shielding vent ring provided by the embodiment of the present application is formed as a complete single piece through the integrated structure, which can realize the edge shielding of the wafer and the exhaust function of the processing cavity structure at the same time. Due to the single-piece arrangement, the pollution problem of the wafer surface caused by the crystal peeling-off existing in the gap of the combined structure in the traditional combined piece is avoided. Moreover, the shielding vent ring of the present application is arranged on the outer ring of the shielding vent ring, which is away from the wafer surface. Even if crystal accumulation is formed around the vent holes, the wafer surface will not be contaminated, which reduces the risk of wafer contamination in the reaction cavity structure.

[0059] Based on the same concept, also referring to FIGS. 1-7, the embodiment of the present application further provides a reaction cavity structure.

[0060] Specifically, the reaction cavity structure 201 of the embodiment of the present application includes a heating platform 202, a shower plate 205 and the above-mentioned shielding vent ring 101. The shower plate 205 is located above the reaction cavity structure 201, and the heating platform 202 is located below the shower plate 205. The heating platform 202 moves up and down in the cavity by relying on the support.

[0061] The inner wall of the reaction cavity structure 201 is provided with a fixed annular boss 203 which is protruded inward from the inner wall of the reaction cavity structure, so that the cross-sectional view of the reaction cavity structure 201 is in an "L" shape structure. The annular boss 203 is located below the shower plate 205. The supporting surface of the annular boss 203 is provided with at least two upward boss protrusions 204, which are used to embed the limiting grooves 106 on the shielding vent ring 101 through the protrusions 204 on the annular boss 203 when the shielding vent ring 101 in the reaction cavity is placed on the annular boss 203, so as to fix the shielding vent ring 101 on the annular boss 203.

[0062] In the initial state and the process end state, the heating table in the reaction cavity structure is located at the starting position, and in the embodiment of the present application, the starting position of the heating table 202 is below the annular boss 203 in the reaction cavity structure, which is convenient for placing or taking out the wafer. After the wafer is placed on the heating table 202, the heating table 202 moves upward until it reaches the process position. In the process of upward movement of the heating table 202, after contacting the shielding vent ring 101 placed on the annular boss 203, the heating table 202 will lift the shielding vent ring 101 to separate from the annular boss 203, so that the inner periphery 102 of the shielding vent ring 101 is overlapped on the edge part of the heating table 202 and moves upward together with the heating table 202 until it reaches the process position. The shielding vent ring can shield the edge of the wafer during the process.

[0063] When the thin film deposition process is carried out in the reaction cavity structure, the gas in the reaction cavity structure is discharged through the vent holes 105 on the shielding vent ring 101.

[0064] In a specific implementation, the height difference between the inner periphery 102 and the outer periphery 103 of the shielding vent ring 101 is less than the thickness of the heating table 202. During the process, the outer periphery 103 of the shielding vent ring 101 is always located between the outer periphery of the heating table 202 and the cavity wall of the reaction cavity structure, which divides the reaction cavity into a first space 206 and a second space 207. The first space 206 includes the upper surface of the heating table 202 and the shower plate 205, and the second space 207 includes the exhaust port of the reaction cavity structure. During the thin film deposition process, the spalling contaminants or deposits generated in the cavity will be directly discharged from the chamber through the uniformly distributed vent holes 105 on the outer periphery 103 of the shielding vent ring 101, avoiding pollution to other components in the reaction cavity structure 201. The reaction cavity structure provided in the embodiment of the present application is provided with a fixed annular boss on the inner wall, and the supporting surface of the annular boss is provided with upward boss protrusions which are used to be embedded with the limiting grooves on the outer periphery of the shielding vent ring, so as to realize the fixation of the shielding vent ring.

[0065] In the description of the application, it needs to be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can be explicitly or implicitly included one or more. In the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0066] In the description of the application, it needs to be explained that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific situation.

[0067] In the description of the specification, the specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable way.

[0068] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the application, and not to limit it; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A shrouded exhaust ring characterized in that, The shielding exhaust ring is applied to a reaction cavity structure of a plasma processing device, and includes an inner ring circumference and an outer ring circumference extending outward from the inner ring circumference by a preset width. An inner diameter of the inner ring circumference is smaller than a diameter of a wafer to be processed by the plasma processing device, and an outer diameter of the inner ring circumference is greater than or equal to the diameter of the wafer. The inner ring circumference is used to shield an edge area of the wafer. A plurality of air holes are arranged on the outer ring circumference, and are used to exhaust reaction gas in the reaction cavity structure.

2. The shrouded exhaust ring of claim 1, wherein, A height of the inner ring circumference is higher than a height of the outer ring circumference. The inner ring circumference and the outer ring circumference are connected by a connecting surface arranged in a circumferential direction.

3. The shrouded exhaust ring of claim 2, wherein, The outer diameter of the inner ring circumference is greater than or equal to a diameter of a heating table of the reaction cavity structure.

4. The shrouded exhaust ring of claim 1, wherein, A lower surface of the outer ring circumference is provided with at least two limiting grooves.

5. The shrouded exhaust ring of claim 1, wherein, Each of the air holes is arranged in a vertical direction and is uniformly distributed on the outer ring circumference.

6. The shrouded exhaust ring of claim 3, wherein, The preset width is a distance between an edge of the heating table and an inner wall of the reaction cavity structure.

7. A reaction cavity structure, characterized by, The reaction cavity structure comprises: a shower plate arranged at an upper portion of the reaction cavity structure; a heating table arranged below the shower plate and used to place a wafer; a lifting structure used to drive the heating table to lift between a starting position and a process position; The shielding exhaust ring according to any one of claims 1-5, wherein the inner ring circumference of the shielding exhaust ring is placed on the heating table and is used to shield an edge area of the wafer, and the outer ring circumference of the shielding exhaust ring is arranged between the heating table and an inner wall of the reaction cavity to exhaust reaction gas in the reaction cavity structure through the air holes on the outer ring circumference.

8. The reaction cavity structure of claim 7, wherein, The inner wall of the reaction cavity structure is provided with a bearing portion protruding inward, the bearing portion is higher than the starting position of the heating table and is lower than the process position of the heating table, and an inner diameter of the bearing portion is smaller than an outer diameter of the outer ring circumference.

9. The reaction cavity structure of claim 8, wherein, The bearing surface of the bearing portion is provided with a same number of protruding portions protruding upward as the limiting grooves of the shielding exhaust ring, the positions of the protruding portions correspond to the limiting grooves, and the protruding portions are used to be fitted with each of the limiting grooves to fix the shielding exhaust ring.

10. The reaction cavity structure of claim 7, wherein, A height difference between the inner ring circumference and the outer ring circumference of the shielding exhaust ring is smaller than or equal to a thickness of the heating table.

11. The reaction cavity structure of claim 8, wherein, The bearing portion is a ring-shaped boss protruding inward from the inner wall of the reaction cavity structure.

12. The reaction cavity structure of claim 8, wherein, The bearing portion is composed of a plurality of bosses protruding inward from the inner wall of the reaction cavity structure.

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