Reaction device

Abstract

The utility model discloses a reaction device, a first flange of the reaction device is provided with a shielding gas channel, when reaction gas is introduced into a reaction chamber to process a silicon wafer, the shielding gas can be introduced into one side of a first end cover synchronously, and the pressure of the shielding gas can be slightly greater than the pressure of the reaction gas at the position of the first end cover; the shielding gas can form micro-positive pressure in the area near the first end cover, so that the reaction gas can be prevented from diffusing to the area near the first end cover, the silicon wafer placing area in the reaction chamber cannot be influenced by excessive diffusion, a furnace door and a furnace mouth metal sealing part can be protected, and the quality of the processed silicon wafer can be improved.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic equipment, and particularly relates to a reaction device. Background Art

[0002] During the preparation of solar cells, silicon wafers need to go through processes such as texturing, diffusion, etching, coating, and printing in sequence. The diffusion process is a core process in the preparation of solar cells. The silicon wafers are placed in a diffusion furnace with a quartz boat as a carrier, and nitrogen, oxygen, and a diffusion source are introduced into the diffusion furnace at a certain temperature to diffusely deposit a PN junction on the surface of the silicon wafers.

[0003] Currently, the diffusion furnace includes a quartz tube. The quartz tube has a reaction chamber. One end of the quartz tube is provided with a furnace opening, and the furnace opening is provided with a stainless - steel furnace door, a quartz furnace door, and a quartz baffle for blocking the furnace opening. When performing the high - temperature diffusion process, the process gas is evenly distributed inside the reaction chamber of the quartz tube. On the one hand, the process gas will chemically react with the stainless - steel furnace door and the metal of the metal sealing flange, resulting in a shortened service life or even damage. On the other hand, the reactants of the process gas and the metal will enter the inner cavity of the quartz tube along with the gas flow, contaminating the silicon wafers and thus affecting the production quality.

[0004] How to protect the furnace door and the metal sealing components at the furnace opening and improve the quality of the silicon wafers after processing is a technical problem that has always concerned those skilled in the art. Summary of the Utility Model

[0005] The purpose of this application is to provide a reaction device that is conducive to protecting the furnace door and the metal sealing components at the furnace opening and improving the quality of the workpiece during the process treatment.

[0006] This application provides a reaction device, including:

[0007] A device main body having a reaction chamber, and the device main body has an opening communicating with the reaction chamber;

[0008] A first end - cover and a first flange. The first end - cover is connected to the opening through the first flange. The first flange is provided with a protective gas channel for blowing protective gas into the area on the side of the first end - cover facing the reaction chamber to inhibit the reaction gas inside the reaction chamber from flowing towards the first end - cover.

[0009] When introducing reaction gas into the interior of the reaction chamber to process the silicon wafer, protective gas can be introduced synchronously to one side of the first end cap. The pressure of the protective gas can be slightly greater than the pressure of the reaction gas at the position of the first end cap. The protective gas can form a slightly positive pressure in the area near the first end cap, which can prevent the reaction gas from diffusing to the vicinity of the first end cap and will not over-diffuse to affect the area where the silicon wafer is placed in the reaction chamber, which is beneficial to improving the process quality of the silicon wafer. And the protective gas channel is arranged on the first flange, and the structure is relatively simple.

[0010] In one example, the protective gas channel includes at least two air outlets, and each of the air outlets is located on the inner ring surface of the first flange and is arranged circumferentially.

[0011] In one example, an exhaust duct is further arranged inside the reaction chamber for extracting the reaction gas inside the reaction chamber from the reaction chamber, and the reaction device further has a flow channel for guiding the protective gas to the exhaust duct.

[0012] In one example, it further includes a second end cap at least partially located inside the reaction chamber. The second end cap is located on the side of the first end cap facing the reaction chamber. An annular mounting surface is provided on the inner wall of the reaction chamber. The second end cap is circumferentially abutted and mounted on the annular mounting surface to isolate the reaction chamber into a first chamber and a second chamber. The second chamber is located between the first end cap and the second end cap; the air outlet of the protective gas channel communicates with the second chamber, and a first channel is provided on the second end cap and / or the annular mounting surface. The second chamber communicates with the first chamber through the first channel, and the flow channel includes the first channel.

[0013] In one example, a groove is provided on the side of the second end cap facing the annular mounting surface and / or on the annular mounting surface, and the space inside the groove forms the first channel.

[0014] In one example, the groove is opened along the radial direction of the second end cap, and a plurality of the grooves are evenly distributed in the circumferential direction of the second end cap.

[0015] In one example, there is a second channel between the second end cap and the inner wall of the second chamber. The flow channel includes the second channel. The protective gas in the second chamber sequentially passes through the second channel and the first channel to communicate with the first chamber and enter the exhaust duct.

[0016] In one example, a baffle is spaced on the side of the second end cap facing the first chamber. A second gap is left between the edge of the baffle and the inner wall of the first chamber. The space between the baffle and the second end cap forms a third channel. The circulation channel includes the third channel. The protective gas entering the first chamber from the first channel passes through the third channel and then enters the exhaust pipe.

[0017] In one example, it further includes a support rod. The support rod passes through the first end cap. The support rod has a shaft section located inside the reaction chamber. The shaft section is used to place a carrier for carrying the processing material.

[0018] In one example, the reaction device is a diffusion furnace for silicon wafer processing.

[0019] In one example, the first flange includes a flange body and an annular pipe. The annular pipe is installed on the inner ring wall of the flange body. The air outlet is arranged on the annular pipe. The annular pipe further includes an air inlet. The flange body is provided with a through hole for connecting the air inlet to an external gas supply pipeline.

[0020] In one example, the annular pipe is an open ring. The annular pipe includes two closed end portions along the circumferential direction. There is a spacing between the two closed end portions.

[0021] In one example, the first flange further includes an inlet pipe. The inlet pipe is an integral structure with the annular pipe, or the inner end of the inlet pipe is fixedly connected to the annular pipe. The inlet pipe is communicated with the annular pipe. The outer end portion of the inlet pipe passes through the through hole and is exposed outside the through hole.

[0022] In one example, the equipment main body has an end pipe section extending into the inner circle of the annular pipe. There is a radial gap between the outer peripheral wall of the end pipe section and the annular pipe. There is a first gap between the end face of the end pipe section and the first end cap. After the protective gas is ejected from the air outlet, it blows into the area on the side of the first end cap facing the reaction chamber along the radial gap and the first gap in sequence. Description of the Drawings

[0023] Figure 1 It is a cross-sectional view of the reaction device in the embodiment of the present application;

[0024] Figure 2 is Figure 1 a top view schematic diagram of the shown reaction device;

[0025] Figure 3 is Figure 1 a partial schematic diagram in;

[0026] Figure 4 isFigure 2 Schematic enlarged view of part B in

[0027] Figure 5 Figure 4 Schematic enlarged view of part C in

[0028] Figure 6 is Figure 1 Schematic structural view of the first flange in

[0029] Figure 7 is Figure 6 Schematic structural view of the annular pipe in

[0030] Figure 8 is Figure 1 Schematic structural view of the second end cap in the reaction device shown in

[0031] Figures 1-8 The reference signs in

[0032] 1 Equipment body; 11 Reaction chamber; 111 First chamber; 112 Second chamber; 101 Annular mounting surface; 102 End pipe section; 103 Radial clearance; 104 First clearance; 12 Heating furnace; 13 Furnace tail; 2 First end cap; 3 First flange; 31 Flange body; 32 Annular pipe; 321 Gas outlet; 33 Inlet pipe; 4 Exhaust pipe; 5 Second end cap; 51 Groove; 52 Through hole; 6 First channel; 7 Baffle; 71 Second clearance; 72 Third channel; 8 Support rod; 81 Shaft section; 9 Carrier vessel. Detailed implementation manners

[0033] The embodiment of the present application provides a reaction device, which can be a tube thermal process device such as a diffusion equipment, a Low Pressure Chemical Vapor Deposition (LPCVD) equipment, a Plasma Enhanced Chemical Vapor Deposition (PECVD) equipment, etc. In this article, the reaction device is taken as a diffusion equipment, specifically, taking a diffusion furnace for processing silicon wafers as an example of the diffusion equipment, the technical solutions and technical effects are further introduced.

[0034] Please refer to Figures 1 to 8 , Figure 1 is a cross-sectional view of the reaction device in the embodiment of the present application; Figure 2 is Figure 1 a top view schematic of the reaction device shown in Figure 3 is Figure 1 a partial schematic in ; 4 is Figure 2 a schematic enlarged view of part B in Figure 5 Figure 4 a schematic enlarged view of part C in Figure 6 isFigure 1 Schematic diagram of the structure of the first flange in Figure 7 is Figure 6 Schematic diagram of the structure of the annular tube in Figure 8 is Figure 1 Schematic diagram of the structure of the second end cap in the reaction device shown. Among them, Figure 4 and Figure 5 The center line S1 in the figure indicates the flow path of the protective gas.

[0035] The reaction device in the embodiment of the present application is a diffusion furnace for silicon wafer processing, which includes a device main body 1. The device main body 1 is the furnace body of the diffusion furnace. As Figure 1 shown, the furnace body is generally cylindrical, and of course, it is not excluded that the furnace body is of other shapes. The inside of the device main body 1 has a reaction chamber 11. The inner wall surrounding the reaction chamber 11 is generally a cylindrical surface, forming a tubular furnace cavity. In the present application, the reaction gas is the gas used for processing the sheet material. For silicon wafer processing, the reaction gases introduced into the diffusion furnace include nitrogen, oxygen, and diffusion sources. Of course, in other devices, the inner wall surrounding the reaction chamber 11 can also be of other shapes, such as cubic shape, etc. The material of the inner wall surrounding the reaction chamber 11 can be quartz material, and of course, it can also be other materials that do not react with the reaction gas. The specific shape of the reaction chamber 11 can be reasonably set according to the specific device type and will not be specifically elaborated herein.

[0036] As Figure 1 and Figure 2 shown, the device main body 1 also includes a heating furnace body 12. The heating furnace body 12 is located on the outer periphery of the reaction chamber 11 and is used to heat the inside of the reaction chamber 11. The heating furnace body 12 can be a tubular heating furnace body. In order to accurately control the temperature inside the reaction chamber 11, one or more temperature sensors can be arranged inside the reaction chamber 11. The temperature sensors are installed at different positions of the reaction chamber 11 to measure the temperature at different positions of the reaction chamber 11. The temperature sensors can specifically be thermocouples.

[0037] The device main body 1 in the embodiment of the present application also has an opening. The opening can communicate with the reaction chamber 11. Through the support rod 8, the carrier 9 for carrying the processing material can be transferred, that is, the carrier 9 is placed into the reaction chamber 11 from the opening, or the carrier 9 is taken out from the reaction chamber 11.

[0038] For the processing material being silicon wafers, several silicon wafers are usually placed in the carrier 9. The carrier 9 can be a quartz boat, a graphite boat, a metal boat, etc. according to different processing technologies. One or two or more carriers 9 can be accommodated inside the reaction chamber 11.

[0039] The support rod 8 has a shaft section 81 located inside the reaction chamber 11, and the carrier container 9 is supported on the shaft section 81. The support rod 8 also has a connection section located outside the reaction chamber 11 for connection and fixation with an external driving mechanism.

[0040] Figure 1 Two parallel support rods 8 are shown in , and the axial direction of the support rod 8 is parallel to the length direction of the device main body 1. In the embodiment of the present application, the reaction device further includes a first end cover 2 and a first flange 3. The first flange 3 is installed at the opening of the reaction chamber 11, and the first end cover 2 is connected to the opening position through the first flange 3 to close the reaction chamber 11. The first end cover 2 can be a metal end cover, such as a stainless steel end cover. Of course, it can also be made of other metal materials or composite metal materials. Of course, it is not excluded that the first end cover 2 is made of a non-metal material, such as quartz.

[0041] When the first end cover 2 is connected to the opening through the first flange 3, the furnace opening is closed. When the first end cover 2 is separated from the first flange 3, the furnace opening is opened. The first end cover 2 and the first flange 3 can be connected and fixed by bolts. The first flange 3 can also be made of metal.

[0042] In the embodiment of the present application, the first flange 3 is provided with a protective gas passage for blowing the protective gas into the area on the side of the first end cover 2 facing the reaction chamber 11. That is to say, the protective gas located outside the reaction chamber 11 can enter the reaction chamber 11 from the protective gas passage provided on the first flange 3 and be blown to the area on one side of the first end cover 2. The protective gas can be nitrogen or other inert gases. In the embodiment of the present application, the protective gas is blown to the area on the side of the first end cover 2 facing the reaction chamber 11 to inhibit the flow of the reaction gas inside the reaction chamber 11 to the first end cover 2, which can prevent the reaction gas from reacting with the first end cover 2 or other sealing components such as the first flange, can protect the furnace door and the metal sealing components at the furnace opening, and can also reduce the generation of metal reactants in the reaction chamber and improve the quality of the processed silicon wafers.

[0043] When introducing the reaction gas into the reaction chamber 11 to process the silicon wafer, the protective gas can be introduced into the side of the first end cover 2 synchronously. The pressure of the protective gas can be slightly greater than the pressure of the reaction gas at the position of the first end cover 2. The protective gas can form a slightly positive pressure in the area near the first end cover 2, which can prevent the reaction gas from diffusing to the area near the first end cover 2 and will not overly diffuse to affect the area where the silicon wafer is placed in the reaction chamber 11.

[0044] In the embodiment of the present application, as Figure 4As shown, the device body 1 also has an air extraction pipeline 4, and the air extraction pipeline 4 can simultaneously extract the reaction gas and the protective gas inside the reaction chamber 11 from the reaction chamber 11. The air extraction pipeline 4 can be arranged near the bottom of the reaction chamber 11. The air extraction pipeline 4 can be one pipeline or several pipelines, and the air extraction ports of each pipeline can be located at different positions. The air extraction port of at least one air extraction pipeline 4 is located near the first end cover 2 to facilitate the outflow of the protective gas from the reaction chamber 11. The reaction device also has a flow channel for guiding the protective gas to the air extraction pipeline 4. The flow channel can be a separate pipeline, or can also be a communication path formed by grooves or channels arranged on the device body 1.

[0045] In the embodiment of the present application, the protective gas channel provided on the first flange 3 can have only one air outlet 321. Of course, it can also include more than two air outlets 321, that is, the air outlets 321 of the protective gas channel include at least two. Each air outlet 321 is located on the inner ring surface of the first flange 3 and is arranged circumferentially. In this way, the protective gas can flow to one side of the first end cover 2 from different circumferential positions, which is beneficial to the uniform distribution of the protective gas on one side of the first end cover 2 to form an air curtain or a similar effect. Preferably, the air outlets 321 of each protective gas channel are evenly arranged circumferentially, so that the protective gas can flow to one side of the first end cover 2 more evenly. The number and size of the air outlets can be determined according to the actual device as long as it can prevent the reaction gas from flowing to the first end cover 2.

[0046] In the embodiment of the present application, the reaction device further includes a second end cover 5. The second end cover 5 is located on the side of the first end cover 2 facing the reaction chamber 11, and the second end cover 5 can be made of quartz. Specifically, an annular mounting surface 101 is provided inside the reaction chamber 11, and the second end cover 5 is circumferentially abutted and mounted against the annular mounting surface 101 to isolate the reaction chamber 11 into a first chamber 111 and a second chamber 112. The second chamber 112 is located between the first end cover 2 and the second end cover 5, and the first chamber 111 is located on the side of the second end cover 5 away from the first end cover 2. The carrier container 9 is placed in the first chamber 111 for processing. The support rod 8 has a shaft section 81 passing through the second chamber 112 and located inside the first chamber 111, and the carrier container 9 is supported on the shaft section 81. Both the first end cover 2 and the second end cover 5 have through holes for the support rod 8 to pass through. Among them Figure 8 the through hole 52 on the second end cover 5 is shown. To a certain extent, the second end cover 5 can play a role in isolating the reaction gas and the first end cover 2 and protecting the first end cover 2.

[0047] In the embodiment of the present application, as shown in the appendix Figure 3 and in the appendix Figure 4As shown, the air outlet of the protective gas passage communicates with the second chamber 112, and the air extraction port of the air extraction pipe 4 is usually located in the first chamber 111. The air extraction pipe 4 can be a structure originally existing in the equipment, so there is no need to design a separate air extraction pipeline specifically for the protective gas; the second chamber 112 can communicate with the first chamber 111 through the first passage 6. Specifically, the first passage 6 can be arranged on the second end cover 5, or can be arranged on the annular mounting surface 101, or the first passage 6 can be arranged on both the second end cover 5 and the annular mounting surface 101 at the same time.

[0048] When the reaction device is in use, the protective gas first blows from the protective gas passage on the first flange 3 to the second chamber 112, and then flows to the first chamber 111 through the first passage 6. Under the action of the air extraction operation, the protective gas can flow from the air extraction port to the outside of the reaction chamber 11.

[0049] In the embodiment of the present application, a groove 51 is provided on one side of the second end cover 5 facing the annular mounting surface 101 and / or on the annular mounting surface 101, and the space in the groove 51 forms the first passage. That is to say, the groove 51 can be processed only on the annular mounting surface 101 or the second end cover 5, and the processing technology is relatively simple. Of course, the groove can also be processed on both the annular mounting surface 101 and the second end cover 5 at the same time. The grooves on the annular mounting surface 101 and the second end cover 5 enclose to form the first passage. In this way, less material is removed from the second end cover 5 and the equipment main body 1 locally, which is beneficial to enhancing the use strength of the local position, and further improving the overall service life of the first end cover 2 and the equipment main body 1.

[0050] In the above embodiment, a groove 51 is provided on at least one of the second end cover 5 and the annular mounting surface 101. When the second end cover 5 and the annular mounting surface 101 are cooperatively and tightly installed, the protective gas in the second chamber 112 can enter the first chamber 111 along the groove 51 between the two.

[0051] In the embodiment of the present application, the groove 51 is provided on the second end cover 5, the groove 51 is radially opened along the second end cover 5, and a plurality of grooves 51 are evenly distributed in the circumferential direction of the second end cover 5 so that the protective gas can enter the first chamber 111 evenly in the circumferential direction.

[0052] In the embodiment of the present application, there is a second passage between the second end cover 5 and the inner wall of the second chamber 112. The second passage can be an annular gap, that is, a radial annular gap is formed between the outer edge of the second end cover 5 and the inner wall of the second chamber 112. The flow passage includes the second passage. The protective gas in the second chamber 112 sequentially passes through the second passage and the first passage 6 to communicate with the first chamber 111. Under the action of air extraction, the protective gas is drawn into the air extraction pipe 4 together with the reaction gas.

[0053] In this embodiment, the second channel is formed between the second end cap 5 and the second chamber 112. By only controlling the processing dimensions of the reaction chamber 11 of the device main body 1 and the second end cap 5, the formation of the second channel can be achieved. The processing technology is simple, and no other components are required, so the structure is simple.

[0054] In the embodiment of the present application, a baffle 7 is provided at intervals on the side of the second end cap 5 facing the first chamber 111. A second gap 71 is left between the edge of the baffle 7 and the inner wall of the first chamber 111. The space between the baffle 7 and the second end cap 5 forms a third channel 72. The flow channel includes the third channel 72. The second gap 71 ensures the connection between the third channel 72 and the first channel 6. The protective gas entering the first chamber 111 from the first channel 6 enters the suction port of the suction pipe 4 after passing through the third channel 72.

[0055] To a certain extent, the baffle 7 can further prevent the reaction gas in the first chamber 111 from flowing towards the second end cap 5 side, making the reaction gas as much as possible in the position where the carrier container 9 is located, enabling the silicon wafer to be in full contact with the reaction gas, and minimizing the reaction gas flowing towards the first end cap 2 side.

[0056] In the embodiment of the present application, the first flange 3 includes a flange body 31 and an annular pipe 32. The flange body 31 and the annular pipe 32 are of a split structure. They are formed separately through individual production and then assembled into a component. The annular pipe 32 is installed on the inner ring wall of the flange body 31. The air outlet is provided on the annular pipe 32. The annular pipe 32 also includes an air inlet. The flange body 31 is provided with a through hole for connecting the air inlet to an external gas supply pipeline.

[0057] In this embodiment, processing the first flange 3 into two split structures can reduce the processing technology of the gas channel inside the first flange 3. Moreover, the annular pipe 32 can be disassembled from the flange body 31, which is convenient for maintenance and can also be replaced separately, reducing the maintenance cost of the reaction device.

[0058] In the embodiment of the present application, the annular pipe 32 is an open ring. The annular pipe 32 includes two closed ends along the circumferential direction, and there is a spacing between the two closed ends. The two closed ends of the open ring can move relatively closer under the action of pressure, so as to appropriately change the diameter of the annular pipe 32, which is convenient for installation.

[0059] In the embodiment of the present application, the first flange 3 further includes an air inlet pipe 33. The air inlet pipe 33 and the annular pipe 32 are of an integral structure. Compared with the air inlet pipe 33 and the annular pipe 32 being of a split structure, they are integrally formed in the same process without subsequent assembly, reducing the leakage risk at the connection position between the two.

[0060] In another embodiment, the inner end of the intake pipe 33 is fixedly connected to the annular pipe 32. The intake pipe 33 communicates with the annular pipe 32, and the outer end portion of the intake pipe 33 passes through the through hole and is exposed outside the through hole. In this embodiment, the intake pipe 33 and the annular pipe 32 are of a split structure, and the two can be processed independently. The processing technology is relatively low, and when assembled with the flange body 31, the assembly flexibility is relatively high.

[0061] In the embodiment of the present application, the equipment main body 1 has an end pipe section 102 extending into the inner ring of the annular pipe 32. There is a radial gap 103 between the outer peripheral wall of the end pipe section 102 and the annular pipe 32, that is to say, the end pipe section 102 is nested in the inner ring of the annular pipe 32, and there is a gap between the two in the radial direction. There is a first gap 104 between the end face of the end pipe section 102 and the first end cover 2. After the protective gas is ejected from the air outlet of the annular pipe 32, it blows into the area on the side of the first end cover 2 facing the reaction chamber 11 in sequence along the radial gap 103 and the first gap 104.

[0062] In the above embodiment, after the protective gas is ejected from the air outlet of the annular pipe 32, it first flows to the radial gap 103 between the end pipe section 102 and the annular pipe 32, then flows from the radial gap 103 to the first gap 104 between the end pipe section 102 and the first end cover 2, and then flows to the first chamber 111 between the first end cover 2 and the second end cover 5. This is beneficial for the protective gas to slowly flow into the interior of the first chamber 111.

[0063] For other structures of the reaction device, please refer to the prior art and will not be elaborated herein.

[0064] In the description of the present application, it should be noted that in the embodiments of the present application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0065] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected and the relative positional relationship after connection remains unchanged.

[0066] The orientation terms mentioned in the embodiments of the present application, such as "inside", "outside", etc., are only references to the directions in the accompanying drawings. Therefore, the orientation terms used are for better and clearer illustration and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be construed as a limitation to the embodiments of the present application. In addition, unless otherwise specified in the present application, the "plurality" described in the present application means two or more.

[0067] In the description of the embodiments of the present application, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising that element.

[0068] In the embodiments of the present application, "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0069] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A reaction device, characterized in that: include: The device body has a reaction chamber, and the device body has an opening communicating with the reaction chamber; A first end cover and a first flange, wherein the first end cover is connected to the opening through the first flange, and the first flange is provided with a protective gas channel for blowing protective gas into an area of ​​the first end cover facing a side of the reaction chamber to inhibit the reaction gas inside the reaction chamber from flowing toward the first end cover.

2. The reaction device according to claim 1, characterized in that: The protective gas channel includes at least two gas outlets, each of which is located on the inner annular surface of the first flange and arranged along the circumferential direction.

3. The reaction device according to claim 1, characterized in that: The reaction chamber is also provided with an exhaust pipe for extracting the reaction gas inside the reaction chamber out of the reaction chamber. The reaction device also has a flow channel for guiding the protective gas to the exhaust pipe.

4. The reaction device according to claim 3, characterized in that: It also includes a second end cover at least partially located inside the reaction chamber, the second end cover is located on the side of the first end cover facing the reaction chamber, the inner wall of the reaction chamber is provided with an annular mounting surface, the second end cover is circumferentially mounted against the annular mounting surface to isolate the reaction chamber into a first chamber and a second chamber, the second chamber is located between the first end cover and the second end cover; the gas outlet of the protective gas channel is connected to the second chamber, the second end cover and / or the annular mounting surface are provided with a first channel, the second chamber is connected to the first chamber through the first channel, and the circulation channel includes the first channel.

5. The reaction device according to claim 4, characterized in that: A groove is provided on a side of the second end cover facing the annular mounting surface and / or on the annular mounting surface, and the space inside the groove forms the first channel.

6. The reaction device according to claim 5, characterized in that: The groove is opened along the radial direction of the second end cover, and a plurality of the grooves are evenly distributed in the circumferential direction of the second end cover.

7. The reaction device according to claim 4, characterized in that: A second channel is provided between the second end cover and the inner wall of the second chamber, the flow channel includes the second channel, and the protective gas in the second chamber is connected to the first chamber through the second channel and the first channel in sequence to enter the exhaust pipe.

8. The reaction device according to claim 7, characterized in that: A baffle is arranged at intervals on the side of the second end cover facing the first chamber, a second gap is left between the edge of the baffle and the inner wall of the first chamber, the space between the baffle and the second end cover forms a third channel, the circulation channel includes the third channel, and the protective gas entering the first chamber from the first channel passes through the third channel and then enters the exhaust pipe.

9. The reaction device according to any one of claims 1 to 8, characterized in that: It also includes a support rod, which is passed through the first end cover and has an axial section located inside the reaction chamber, and the axial section is used to place a carrying container carrying the processed material.

10. The reaction device according to claim 1, characterized in that: The reaction device is a diffusion furnace used for silicon wafer processing.

11. The reaction device according to claim 2, characterized in that: The first flange includes a flange body and an annular tube, the annular tube is installed on the inner ring wall of the flange body, the air outlet is arranged on the annular tube, the annular tube also includes an air inlet, and the flange body is provided with a through hole for connecting the air inlet with an external air supply pipeline.

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