Preheat ring and semiconductor device

Abstract

The utility model provides a preheating ring and semiconductor equipment. Wherein the ring surface width of the gas inlet end part in the preheating ring is greater than that of the gas outlet end part, so that the contact area between the reaction gas and the gas inlet end part can be increased, the heating activation effect on the reaction gas is improved, and the reaction uniformity of each region on the surface of the wafer is optimized. And the gas inlet end part is of a wave-shaped structure with different densities, so that on one hand, the contact area between the reaction gas and the gas inlet end part can be further increased, the heating activation effect on the reaction gas can be improved, and on the other hand, the reaction gas can be subjected to uniform flow treatment, so that the uniform flow of the reaction gas is ensured; uniform reaction of all areas on the surface of the wafer can be achieved, and the problem that film growth, etching and ion doping on the wafer are not uniform is effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor manufacturing, in particular to a preheating ring and semiconductor equipment. Background Art

[0002] Epitaxy (EPI) refers to the process of growing orderly arranged single crystal layers on a substrate to improve device performance. At present, with the development of semiconductor technology, the reduced pressure chemical vapor deposition (RPCVD) equipment used in the EPI process will dope the epitaxial layer with boron ions and phosphorus ions to increase the concentration of electrons and holes and improve the carrier migration rate, thereby meeting the device performance requirements.

[0003] However, as the concentration of ion doping increases, the flow rate of the precursor gas used in the equipment also gradually increases, which can easily lead to a large amount of gas that has not had time to be activated entering the chamber, resulting in large differences in ion concentrations in different areas of the epitaxial layer. Figure 1 As shown in FIG. 1 , when a silicon germanium epitaxial layer is deposited in an existing small chamber using a narrow preheating ring, the concentration of boron ions is detected by using a secondary ion mass spectrometer (SIMS). It can be clearly seen that the ion concentration in the edge area is generally higher than that in the center area, and the maximum ion concentration difference is about 30%. And, as Figure 2 As shown in the figure, when a wide preheating ring is used to deposit a silicon-phosphorus epitaxial layer in an existing large chamber, the concentration of phosphorus ions is detected by SIMS. It can be clearly seen that the ion concentration in the edge area is higher than that in the center area, and the maximum ion concentration difference is about 20%. Although a larger reaction chamber and a wide preheating ring can alleviate the maximum ion concentration difference, it still cannot improve the uniformity of ion doping, and the larger chamber structure and preheating ring also increase the equipment cost. In addition, the difference in gas activation amount also has an adverse effect on the uniformity of the growth thickness of the epitaxial layer. Figure 3 As shown, a large amount of precursor gas that has not had time to activate continues to activate in the edge area of ​​the wafer without participating in the growth, resulting in a higher growth thickness in the middle area of ​​the wafer and a lower thickness in the edge and center areas of the wafer. As a result, the electrical performance of the semiconductor device varies greatly in different areas, seriously affecting the chip yield.

[0004] Therefore, a new process equipment is urgently needed to solve the above technical problems. Utility Model Content

[0005] The utility model aims to provide a preheating ring and semiconductor equipment to solve at least one problem of how to improve the heating and activation effect of reaction gas and how to improve the reaction uniformity of ion doping, film growth and film etching.

[0006] In order to solve the above technical problems, the utility model provides a preheating ring for preheating reaction gas, comprising: an annular structure;

[0007] The annular structure has an air inlet end and an air outlet end; the reaction gas flows into the ring of the annular structure through the air inlet end and flows out through the air outlet end; wherein the annular surface corresponding to the air inlet end is wider than the annular surface corresponding to the air outlet end; and along the annular direction of the annular structure, the air inlet end presents a wave shape with different densities.

[0008] Optionally, in the preheating ring, the density of the wavy structure of the air inlet end increases along the annular direction of the annular structure and in the direction from the central area of ​​the air inlet end toward the edge area of ​​the air inlet end; wherein the central area of ​​the air inlet end corresponds to the flow center of the reaction gas.

[0009] Optionally, in the preheating ring, the density of the wavy structure at the air inlet end satisfies the following formula:

[0010] m1:m2:m3=k1:k2:k3;

[0011] wherein m1, m2 and m3 are respectively the number of wave crests in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; or, m1, m2 and m3 are respectively the number of wave troughs in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; or, m1, m2 and m3 are respectively the sum of the number of wave crests and wave troughs in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; and m1≠0, m2≠0 and m3≠0;

[0012] k1, k2 and k3 are all proportional constants, and k1=1, 2≤k2≤3, 3≤k3≤5.

[0013] Optionally, in the preheating ring, the annular surface corresponding to the air inlet end and the annular surface corresponding to the air outlet end satisfy the following formula:

[0014] (d1-d2) / d2=n;

[0015] Wherein, d1 is the maximum width of the annular surface corresponding to the air inlet end;

[0016] d2 is the minimum width of the annular surface corresponding to the gas outlet end;

[0017] n is a proportional constant and its range is: 1≤n≤2.

[0018] Optionally, in the preheating ring, the angle between the annular surface of the annular structure and the surface where the inner ring of the annular structure is located is an acute angle.

[0019] Optionally, in the preheating ring, the range of the angle θ between the annular surface of the annular structure and the surface where the inner ring of the annular structure is located is: 1°≤θ≤10°.

[0020] Optionally, in the preheating ring, an angle between the annular surface corresponding to the air inlet end and the surface where the inner ring of the annular structure is located is different from an angle between the annular surface corresponding to the air outlet end and the surface where the inner ring of the annular structure is located.

[0021] Optionally, in the preheating ring, the inner ring center of the annular structure does not coincide with the outer ring center of the annular structure, and the inner ring center of the annular structure is closer to the air outlet end relative to the outer ring center of the annular structure.

[0022] Optionally, in the preheating ring, the annular structure is wavy along the annular direction of the annular structure.

[0023] Based on the same concept, the utility model also provides a semiconductor device, including a reaction chamber and the preheating ring; wherein the preheating ring is accommodated in the reaction chamber, and a heat source is provided in the reaction chamber, and the heat source can heat the preheating ring so that the preheating ring preheats the reaction gas.

[0024] In summary, the utility model provides a preheating ring and semiconductor equipment. Compared with the prior art, the ring surface width of the air inlet end in the preheating ring is larger than that of the air outlet end, so as to increase the contact area between the reaction gas and the air inlet end, thereby improving the heating and activation effect of the reaction gas and achieving uniform reaction of each area on the surface of the wafer. In addition, the air inlet end presents a wavy structure with different densities. On the one hand, it can further increase the contact area between the reaction gas and the air inlet end, improve the heating and activation effect of the reaction gas, and on the other hand, it can perform uniform flow treatment on the airflow of the reaction gas to ensure uniform gas flow, which is conducive to achieving uniform reaction of each area on the surface of the wafer and effectively alleviating the problem of uneven thin film growth, etching and ion doping on the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Those skilled in the art will appreciate that the drawings are provided for a better understanding of the present invention, but do not constitute any limitation on the scope of the present invention.

[0026] Figure 1 It is a line graph of ion doping concentrations in the center and edge regions of a wafer using a narrow preheat ring in a small chamber in the prior art.

[0027] Figure 2 It is a line graph of ion doping concentrations in the center and edge regions of a wafer using a wide preheat ring in a large chamber in the prior art.

[0028] Figure 3 It is a line graph of the epitaxial layer deposition thickness on each area of ​​the wafer in the prior art.

[0029] Figure 4 A top view of a preheating ring in an embodiment of the utility model.

[0030] Figure 5 It is a top view of another preheating ring in an embodiment of the utility model.

[0031] Figure 6 It is a schematic diagram of the position and size relationship of the widest annular surface at the air inlet end and the narrowest annular surface at the air outlet end in the embodiment of the utility model.

[0032] Figure 7 It is a side view of the wavy structure in the embodiment of the utility model and a schematic diagram of the density.

[0033] Figure 8 It is a schematic diagram of the embodiment of the utility model in which the ring surface and the inner ring surface are arranged at an angle.

[0034] Fig. 9 It is a schematic diagram of different included angles between the annular surface at the air inlet end and the annular surface at the air outlet end and the inner ring surface in an embodiment of the utility model.

[0035] Fig.10 It is a structural schematic diagram of a semiconductor device in an embodiment of the utility model.

[0036] And, in the attached drawings:

[0037] 10-annular structure; 100a-inner ring; 100b-outer ring; 101-inlet end; 102-outlet end;

[0038] 20-reaction chamber; 201-air inlet; 202-air outlet;

[0039] G-reaction gas; O1-center of the outer ring; O2-center of the inner ring; θ1-first angle; θ2-second angle; W-wafer; V-direction from the central area of ​​the inlet end to the edge area of ​​the inlet end; Q1-central area; Q2-area between the central area and the edge area; Q3-edge area; d1-maximum width of the annular surface corresponding to the inlet end; d2-minimum width of the annular surface corresponding to the outlet end. DETAILED DESCRIPTION

[0040] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing to be shown is different, and sometimes different proportions are used. It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third" and the like in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, rather than to represent the logical relationship or sequential relationship between the various components, elements, steps, etc. And, the X-axis direction, Y-axis direction and Z-axis direction referred to in the specification and the drawings of this application are three directions perpendicular to each other in three-dimensional space.

[0041] See also Figure 4 and Figure 5 This embodiment provides a preheating ring for preheating a reaction gas G. The preheating ring comprises: an annular structure 10; the annular structure 10 has an inlet end 101 and an outlet end 102; the reaction gas G flows into the ring of the annular structure 10 through the inlet end 101 and flows out through the outlet end 102; wherein the annular surface corresponding to the inlet end 101 is wider than the annular surface corresponding to the outlet end 102; and along the annular direction of the annular structure 10, the inlet end 101 presents a wave shape with different densities.

[0042] It can be seen that the preheating ring provided in this embodiment uses the ring surface width of the inlet end 101 to be greater than the outlet end 102 to increase the contact area between the reaction gas G and the inlet end 101, improve the heating and activation effect of the reaction gas G before entering the ring, and help the uniformity of film growth and ion doping in various areas of the wafer surface. In addition, the inlet end 101 has a wavy structure with different densities. On the one hand, it can further increase the contact area between the reaction gas G and the inlet end 101, improve the heating and activation effect of the reaction gas G, and on the other hand, it can perform uniform flow processing on the gas flow of the reaction gas G to ensure uniform gas flow, effectively alleviating the problem of uneven film growth, etching and ion doping on the wafer.

[0043] The following is combined with Figures 4 to 10 , specifically describe the preheating ring provided in this embodiment.

[0044] Please continue reading Figure 4 and Figure 5, the preheating ring provided in this embodiment is used to heat the reaction gas G during the semiconductor preparation process to fully activate it and meet the reaction conditions. Wherein, the reaction gas G includes but is not limited to thin film growth gas, etching gas or other cleaning gas. Specifically, the preheating ring includes an annular structure 10. The annular structure 10 can be a standard circular ring structure or a quasi-circular ring structure, which is not specifically limited in this embodiment. And the annular structure 10 is generally made of a material with high thermal conductivity and high heat resistance. For example, the annular structure 10 is made of materials such as graphite, quartz or silicon carbide, and can be heated by irradiation with a heating lamp or induction by an induction heating furnace. Alternatively, if the material of the annular structure 10 is metal, the preheating ring also includes a conductive structure (not shown) to conduct conductive heating to the annular structure 10 through the conductive structure.

[0045] Furthermore, the annular structure 10 has an inlet end 101 and an outlet end 102, and the wafer is located in the ring of the annular structure 10. In the reaction process, the reaction gas G will flow into the ring of the annular structure 10 through the inlet end 101 to contact the surface of the wafer, and then flow out from the outlet end 102. It can be understood that before the reaction gas G reacts with the surface of the wafer, the reaction gas G is mainly heated by the inlet end 101. Therefore, in order to ensure that the reaction gas G is fully heated and activated, the annular surface corresponding to the inlet end 101 in the annular structure 10 provided in this embodiment is wider than the annular surface corresponding to the outlet end 102, so as to increase the contact area between the inlet end 101 and the reaction gas G, which is conducive to the sufficient heating of the reaction gas G.

[0046] It should be noted that this embodiment does not specifically limit the size of the widened air inlet end 101. Figure 6 As shown, the annular surface corresponding to the air inlet end 101 and the annular surface corresponding to the air outlet end 102 satisfy the following formula:

[0047] (d1-d2) / d2=n;

[0048] Wherein, d1 is the maximum width of the annular surface corresponding to the air inlet end 101; d2 is the minimum width of the annular surface corresponding to the air outlet end 102; n is a proportional constant, and the range is: 1≤n≤2. In other words, in this embodiment, the widened widest annular surface in the air inlet end 101 is 1 to 2 times wider than the narrowest annular surface in the air outlet end 102.

[0049] Furthermore, this embodiment does not limit the specific shape of the air inlet end 101. The air inlet end 101 may be as follows: Figure 5 and Figure 6As shown, the air inlet end 101 may protrude from other areas of the annular structure 10, so that the outer ring 100b of the annular structure 10 is similar to a circle. Figure 4 As shown, the outer ring 100 b of the annular structure 10 does not protrude from other areas of the annular structure 10 , so the outer ring 100 b of the annular structure 10 remains as a standard circle.

[0050] Please continue reading Figure 4 and Figure 5 , considering that the annular surface corresponding to the inlet end 101 is wider than the annular surface corresponding to the outlet end 102, and without increasing the overall size of the annular structure 10, the annular structure 10 is preferably an eccentric annular structure. That is, the outer ring center O1 of the annular structure 10 does not coincide with the inner ring center O2 of the annular structure 10, and the inner ring center O2 of the annular structure 10 is closer to the outlet end 102 than the outer ring center O1 of the annular structure 10. Based on this, during the process implementation, the position of the wafer relative to the annular structure 10 is closer to the outlet end 102. It can be understood that, when the flow rate of the reaction gas G is constant, the time spent by the reaction gas G flowing through the inlet end 101 is shorter than the time spent flowing through the outlet end 102, so that the time for the reaction gas G to be heated before entering the ring is prolonged, so that it can be more fully activated, which is conducive to improving the uniformity of thin film growth, film layer etching and ion doping. The waste gas formed after the fully activated reaction gas G reacts with the surface of the wafer and the part of the unreacted reaction gas G stays on the gas outlet end 102 for a relatively short time, so that they can quickly flow out of the annular structure 10. And because of the rapid outflow of these gases, the heat dissipation time of these gases is short, and they can still maintain a high temperature when entering the outflow pipe of the equipment, thereby reducing the deposition of reactants and contaminant particles in the outflow pipe and improving the cleanliness of the reaction chamber. And when the reaction gas G is an etching gas, it is also beneficial to etch and remove the sediment accumulated in the outflow pipe for a long time, ensuring that the equipment has better cleanliness.

[0051] See also Figure 5 and Figure 7, based on the flow viscosity of the reaction gas G, the flow velocity and flow rate of the flow center of the reaction gas G will be greater than the flow velocity and flow rate of the flow edge of the reaction gas G. Therefore, when the reaction gas G flows to the inlet end 101, the central area Q1 of the inlet end 101 corresponds to the flow center of the reaction gas G, and the flow velocity and flow rate of the reaction gas G flowing into the ring 100a through the central area Q1 of the inlet end 101 are relatively large, and on the basis of sufficient heating and activation, it is still easy to cause the problem of uneven reaction in various areas of the wafer surface. Therefore, in the annular structure 10 provided in this embodiment, along the annular direction of the annular structure 10, the inlet end 101 is in a wave shape with different densities. And along the circumferential direction of the annular structure 10, in the direction V from the central area Q1 of the air inlet end 101 toward the edge area Q3 of the air inlet end 101, the density of the wavy structure of the air inlet end 101 increases gradually, so that the reaction gas G located at the flow center flows through the sparser wavy structure, and the reaction gas G located at the flow edge flows through the denser wavy structure.

[0052] It can be understood that, on the one hand, the sparse wavy structure provides a lower blocking force relative to the flow center of the reaction gas G, so the release space of the flow center of the reaction gas G is large, which is conducive to reducing the flow center velocity of the reaction gas G; while the dense wavy structure provides a higher blocking force relative to the flow edge of the reaction gas G, so the release space of the flow edge of the reaction gas G is small, which is conducive to increasing the flow center velocity of the reaction gas G, thereby improving the uniform flow effect of the reaction gas G. On the other hand, if the flow center of the reaction gas G has a high velocity, the molecular motion is highly active, and the sparse wavy structure has a smaller contact area with the reaction gas G than the dense wavy structure, so the flow center of the reaction gas G can be appropriately heated and activated; while the flow center of the reaction gas G has a low velocity, the molecular motion is low, and the dense wavy structure has a larger contact area with the reaction gas G than the sparse wavy structure, so the flow edge of the reaction gas G can be fully heated and activated, thereby facilitating the uniformity of the wafer surface reaction. Preferably, along the annular direction of the annular structure 10 , the annular structure 10 as a whole may be wavy. Compared with a flat annular surface, the wavy annular surface has a larger contact area with the reaction gas G, and has a better activation effect.

[0053] Furthermore, the present embodiment does not limit the specific density of each region of the wavy annular structure 10, which can be determined according to factors such as the flow rate, flow rate and direction of the reaction gas G. Preferably, as Figure 7 As shown, the density of the wave-shaped structure of the air inlet end 101 satisfies the following formula:

[0054] m1:m2:m3=k1:k2:k3;

[0055] Among them, m1, m2 and m3 are respectively the number of peaks in the central area Q1 of the intake end 101, the area Q2 between the central area Q1 and the edge area Q3, and the edge area Q3; or, m1, m2 and m3 are respectively the number of troughs in the central area Q1 of the intake end 101, the area Q2 between the central area Q1 and the edge area Q3, and the edge area Q3; or, m1, m2 and m3 are respectively the sum of the number of peaks and troughs in the central area Q1 of the intake end 101, the area Q2 between the central area Q1 and the edge area Q3, and the edge area Q3; and m1≠0, m2≠0 and m3≠0; k1, k2 and k3 are all proportional constants, and k1=1, 2≤k2≤3, 3≤k3≤5.

[0056] For example, m1, m2 and m3 are respectively the number of valleys in the central area Q1 of the air inlet end 101, the area Q2 between the central area Q1 and the edge area Q3, and the edge area Q3. Figure 7 As shown: m1=1; m2=2; m3=3; then m1:m2:m3=1:2:3. In other examples, m1:m2:m3=1:3:3; or m1:m2:m3=1:3:4; or m1:m2:m3=1:3:5, etc. Also, in other examples, m1, m2, and m3 can be the number of peaks in the corresponding area, or the sum of the number of peaks and troughs in the corresponding area.

[0057] See also Figure 5 , Figure 8 and Fig. 9In order to further increase the contact area between the reaction gas G and the annular structure 10, improve the heating activation effect, improve the utilization rate of the reaction chamber, and reduce the structure of the reaction chamber, the angle between the annular surface of the annular structure 10 provided in this embodiment and the surface where the inner ring 100a of the annular structure 10 is located is an acute angle. It should be noted that the surface where the inner ring 100a referred to in this embodiment coincides with or is parallel to the plane where the wafer W located within the annular structure 10 is located. Based on this, it can be understood that the contact area between the annular surface of the annular structure 10 set at an angle relative to the surface where the inner ring 100a of the annular structure 10 is located and the reaction gas G is much larger than the contact area between the flat annular structure 10 and the reaction gas G, which is conducive to fully activating the reaction gas G and improving the uniformity of thin film growth, film layer etching and ion doping. At the same time, under the condition of the same contact area with the reaction gas G, the annular structure 10 with a truncated cone-shaped overall structure has a smaller size in the plane where the X-axis-Y-axis is located than the annular structure 10 with a planar shape, which is conducive to improving the utilization rate of the reaction chamber, reducing the structure of the reaction chamber, and reducing the equipment cost. Preferably, the angle between the annular surface of the annular structure 10 and the surface where the inner ring 100a of the annular structure 10 is located is greater than or equal to 1° and less than or equal to 10°. Also, the first angle θ1 of the annular surface corresponding to the air inlet end 101 relative to the surface where the inner ring 100a of the annular structure 10 is located and the second angle θ2 of the annular surface corresponding to the air outlet end 102 relative to the surface where the inner ring 100a of the annular structure 10 is located may be the same or different. That is, 1°≤θ1≤10°, 1°≤θ2≤10°, and θ1=θ2 or θ1≠θ2. For example, as Fig. 9 As shown, θ1>θ2, the waste gas formed after the reaction and part of the unreacted reaction gas G can quickly flow out of the reaction chamber through the gas outlet end 102, thereby improving the cleanliness of the reaction chamber.

[0058] Based on the same idea, see Figure 4 and Fig.10, this embodiment also provides a semiconductor device, including the above-mentioned preheating ring and reaction chamber 20. Wherein, the preheating ring is accommodated in the reaction chamber 20, and a heat source (not shown) is arranged in the reaction chamber 20, and the heat source can heat the preheating ring so that the preheating ring preheats the reaction gas G. Optionally, the heat source is a heating lamp, a resistance furnace or other heat-conducting structure. Further, a carrier (not shown) and a support frame (not shown) are arranged in the reaction chamber 20. The carrier is used to carry the wafer W, and the support frame is used to support the preheating ring, and the wafer W is located in the ring of the preheating ring. Wherein, there is a certain distance between the outer periphery of the wafer W and the inner ring 100a of the preheating ring, so that the reaction gas G can fully contact with the preheating ring and optimize the activation effect thereof. And, the reaction chamber 20 has an air inlet 201 and an air outlet 202. The inlet end 101 in the preheating ring is arranged close to the inlet 201, and the outlet end 102 in the preheating ring is arranged close to the outlet 202, so that the reaction gas G at least sequentially passes through the inlet 201, the inlet end 101, the wafer W and the outlet end 102, and flows out to the outlet 202. Under the special morphology of the preheating ring, it can not only effectively alleviate the uneven problems of thin film growth, film layer etching and ion doping, but also reduce the size of the reaction chamber 20 and improve its space utilization under the premise of improving the reaction uniformity, which is conducive to reducing the equipment cost. Among them, this embodiment does not specifically limit the semiconductor equipment to epitaxial layer growth equipment or other vapor deposition equipment.

[0059] In summary, in the preheating ring and semiconductor equipment provided in this embodiment, the ring surface width of the inlet end 101 in the preheating ring is greater than the outlet end 102, so as to increase the contact area between the reaction gas G and the inlet end 101, thereby improving the heating and activation effect of the reaction gas G and optimizing the reaction uniformity of each area on the surface of the wafer W. In addition, the inlet end 101 is a wave-shaped structure with different densities, which can further increase the contact area between the reaction gas G and the inlet end 101 and improve the heating and activation effect of the reaction gas G. On the other hand, the gas flow of the reaction gas G can be uniformly processed to ensure uniform gas flow, which is conducive to achieving uniform reaction of each area on the surface of the wafer W and improving the uniformity of thin film growth, etching and ion doping. In addition, the ring surface of the annular structure 10 is set at an angle with the surface where the inner ring 100a of the annular structure 10 is located, which is not only conducive to increasing the contact area between the reaction gas G and the ring surface, further improving the heating and activation effect, but also conducive to reducing the size of the reaction chamber 20 and reducing the equipment cost.

[0060] In addition, it should be recognized that although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A preheating ring for preheating reaction gas, characterized in that: include: Ring structure; The annular structure has an air inlet end and an air outlet end; the reaction gas flows into the ring of the annular structure through the air inlet end and flows out through the air outlet end; wherein the annular surface corresponding to the air inlet end is wider than the annular surface corresponding to the air outlet end; and along the annular direction of the annular structure, the air inlet end presents a wave shape with different densities.

2. The preheating ring according to claim 1, characterized in that: Along the annular direction of the annular structure and in the direction from the central area of ​​the inlet end toward the edge area of ​​the inlet end, the density of the wavy structure of the inlet end increases; wherein the central area of ​​the inlet end corresponds to the flow center of the reaction gas.

3. The preheating ring according to claim 2, characterized in that: The density of the wavy structure at the air inlet end satisfies the following formula: m1:m2:m3=k1:k2:k3; wherein m1, m2 and m3 are respectively the number of wave crests in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; or, m1, m2 and m3 are respectively the number of wave troughs in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; or, m1, m2 and m3 are respectively the sum of the number of wave crests and wave troughs in the central area, the area between the central area and the edge area, and the edge area of ​​the air intake end; and m1≠0, m2≠0 and m3≠0; k1, k2 and k3 are all proportional constants, and k1=1, 2≤k2≤3, 3≤k3≤5.

4. The preheating ring according to claim 1, characterized in that: The annular surface corresponding to the air inlet end and the annular surface corresponding to the air outlet end satisfy the following formula: (d1-d2) / d2=n; Wherein, d1 is the maximum width of the annular surface corresponding to the air inlet end; d2 is the minimum width of the annular surface corresponding to the gas outlet end; n is a proportional constant and its range is: 1≤n≤2.

5. The preheating ring according to claim 1, characterized in that: The angle between the annular surface of the annular structure and the surface where the inner ring of the annular structure is located is an acute angle.

6. The preheating ring according to claim 5, characterized in that: The range of the angle θ between the annular surface of the annular structure and the surface where the inner ring of the annular structure is located is: 1°≤θ≤10°.

7. The preheating ring according to claim 5 or 6, characterized in that: The angle between the annular surface corresponding to the air inlet end and the surface where the inner ring of the annular structure is located is different from the angle between the annular surface corresponding to the air outlet end and the surface where the inner ring of the annular structure is located.

8. The preheating ring according to claim 1, characterized in that: The inner circle center of the annular structure does not coincide with the outer circle center of the annular structure, and the inner circle center of the annular structure is closer to the air outlet end relative to the outer circle center of the annular structure.

9. The preheating ring according to claim 1, characterized in that: Along the circumferential direction of the annular structure, the annular structure is wavy.

10. A semiconductor device, characterized in that: It comprises a reaction chamber and a preheating ring as claimed in any one of claims 1 to 9; wherein the preheating ring is accommodated in the reaction chamber, and a heat source is provided in the reaction chamber, and the heat source can heat the preheating ring so that the preheating ring preheats the reaction gas.

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