Structure and method for preventing deposition of heater and improving temperature uniformity of thermal field

Abstract

The invention relates to the technical field of CVD (Chemical Vapor Deposition), in particular to a structure for preventing deposition of a heater and improving temperature uniformity of a thermal field, which comprises a furnace / chamber body, a heat insulation felt assembly, the heater, a heat conduction cylinder assembly, a main furnace chamber heat conduction cylinder support plate, a gas path nozzle and a pressure detection device, a heater and a product are isolated in two areas by adding the heat conduction cylinder assembly with a high heat conduction structure and the graphite paper, so that the product is placed in a high-temperature reaction deposition area, the heater and a heat insulation felt assembly are isolated outside the deposition area, an independent heating area is formed, on one hand, the area of a heating body is improved, and the uniformity of a CVD thermal field is improved; the heat energy is radiated by the heat conduction cylinder assembly, so that a uniform thermal field space can be effectively formed, the temperature control precision is guaranteed, and the yield of SIC products is improved; inert gas is introduced into the heating area to prevent process gas from entering the periphery of the heater, deposition reaction conditions on the heater and the heat insulation felt assembly are prevented, and the service life of the heater and the heat insulation felt assembly is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of CVD chemical vapor deposition, and in particular to a structure and method for preventing heater deposition and improving temperature uniformity of a thermal field. Background Art

[0002] CVD chemical vapor deposition (CVD) is a method for preparing SIC coatings. In the SIC-CVD preparation process, temperature, pressure, and flow are the three important factors for the formation of SIC. Among them, temperature directly affects the lattice order of the SIC coating and changes the physical properties of SIC. Therefore, CVD temperature control is extremely critical. If you want to control the reaction temperature, you must solve the heating and insulation problems. The insulation method of CVD equipment on the market is basically to install the heater inside the furnace chamber, directly heat the substrate through the heater, and install insulation felt between the heater and the inner wall of the furnace chamber to prevent heat from losing to the outside of the furnace chamber. Since the heater, insulation felt, and substrate are all in the process gas atmosphere, the heater and insulation felt have the problem of being deposited. At present, there is no solution to the deposition of heaters and insulation felts on the market. It is mainly for the treatment of heaters and insulation felts after they are deposited. The common practices in laboratories or factories are as follows:

[0003] Solution to the deposition on the heater: Design the heater assembly to be spliced, that is, the heating electrode and the power supply electrode are connected by bolts or clamping, the heating electrode is installed outside the furnace chamber, and isolated by thermal insulation felt to reduce or avoid deposition. The heating electrode is installed inside the furnace chamber and is in the same thermal field space as the deposited product. It is unavoidable that the graphite electrode is coated. When a production cycle is completed, only the heating electrode is disassembled and replaced.

[0004] The solution to the deposition of insulation felt is to change the previous simple soft insulation felt and hard felt into a combination of soft and hard insulation felt. The conventional practice in the factory is to use thick hard felt to attach it to the inner wall of the furnace / chamber, fill thin soft felt between the hard felt in different parts, and cover the hard felt surface with soft felt. In this way, the hard felt can be used in multiple furnaces, and the soft felt can be replaced after each furnace, which can reduce a certain amount of maintenance workload.

[0005] The above two methods only reduce the number of heater and insulation felt consumables and the maintenance workload, which reduces the manpower and time costs to a certain extent. They do not fundamentally eliminate the problem of heating deposition and only treat the symptoms but not the root cause.

[0006] In summary, in order to solve the above-mentioned problem of the heater and the thermal insulation felt being coated, a device can be designed to prevent deposition and improve the uniformity of the CVD thermal field. Summary of the invention

[0007] To overcome the problem the heater and insulation felt were coated.

[0008] The technical solution of the present invention is: a structure for preventing heater deposition and improving temperature uniformity of thermal field, comprising a furnace / chamber body, a heat insulation felt assembly, a heater, a heat conduction tube assembly, a main furnace chamber heat conduction tube support plate, a gas path nozzle and a pressure detection device;

[0009] The furnace / chamber body includes a lower furnace cover, a main furnace chamber body and an upper furnace cover; the main furnace chamber body and the upper furnace cover are sequentially installed on the upper end of the lower furnace cover; the lower furnace cover, the main furnace chamber body and the upper furnace cover are used to provide a closed space required for CVD reaction;

[0010] The thermal insulation felt assembly includes a lower thermal insulation felt, a main furnace chamber thermal insulation felt and an upper thermal insulation felt; the lower thermal insulation felt, the main furnace chamber thermal insulation felt and the upper thermal insulation felt are respectively installed on the inner sides of the lower furnace cover, the main furnace chamber body and the upper furnace cover;

[0011] The heat-conducting tube assembly includes a heat-conducting tube upper cover, a heat-conducting tube body and a heat-conducting tube lower cover; the heat-conducting tube body and the heat-conducting tube lower cover are sequentially installed at the lower end of the heat-conducting tube upper cover; the heat-conducting tube body is connected to the main furnace chamber body through the heat-conducting tube supporting plate of the main furnace chamber; the heat-conducting tube assembly is installed inside the furnace / chamber body to transfer the heat energy of the heater; the inside of the heat-conducting tube assembly is a deposition area, which is used to perform CVD deposition reaction on the product inside;

[0012] Graphite paper is installed on the inner wall of the heat-conducting tube with graphite nails or molybdenum nails to transfer the heat energy of the heat-conducting tube assembly and provide the high-temperature environment required for the CVD reaction; the graphite paper isolates the heat-conducting tube assembly from the reaction gas, and the inside of the graphite paper is the deposition area, which is used to perform CVD deposition reaction on the internal product;

[0013] The gas path nozzle includes an inert gas nozzle, a process gas nozzle and a nozzle insulation sleeve; the process gas nozzle is installed with a nozzle insulation sleeve when passing through the heating area formed by the inner side of the insulation felt assembly and the outer side of the heat-conducting tube assembly; the inert gas nozzle is installed on the furnace / chamber body and is used to introduce inert protective gas;

[0014] The pressure detection device includes an inert gas pressure gauge, a process tail gas pressure gauge, an inert gas pressure regulating valve and a process gas pressure regulating valve; the inert gas pressure gauge is connected to the heating area; the process tail gas pressure gauge is connected to the deposition area; the inert gas pressure gauge and the process tail gas pressure gauge are used to monitor the pressure values ​​of the inert gas and the process gas; the inert gas pressure regulating valve and the process gas pressure regulating valve are used to adjust the pressure values ​​of the inert gas and the process tail gas;

[0015] The heater is installed inside the thermal insulation felt assembly to provide the thermal energy required for the CVD reaction.

[0016] Preferably, the heat-conducting tube assembly can be of an integrated type or a combined type.

[0017] Preferably, the heat-conducting tube assembly in the furnace / chamber body is used to separate the heater and the product. The number of heat-conducting tube assemblies is not limited, and the interior of the furnace / chamber body can be divided into one or more heating areas and deposition areas.

[0018] Preferably, there is an installation gap between the nozzle insulation sleeve and the insulation cylinder assembly body for connecting the heating area and the deposition area.

[0019] Preferably, the number and gas inlet direction of the inert gas nozzles and process gas nozzles are not limited.

[0020] Preferably, the lower insulation felt, the main furnace chamber insulation felt and the upper insulation felt are made of materials with low thermal conductivity and high temperature resistance.

[0021] Preferably, the lower furnace cover, the main furnace chamber body and the upper furnace cover are made of materials with high thermal conductivity and high temperature resistance.

[0022] A method for preventing heater deposition and improving thermal field temperature uniformity includes the structure for preventing heater deposition and improving thermal field temperature uniformity as described above, and the steps are as follows:

[0023] Step 1: Open the inert gas nozzle, inject inert gas into the heating area formed by the inner side of the thermal insulation felt assembly and the outer side of the heat-conducting tube assembly through the inert gas nozzle, open the process tail gas valve, and use inert gas purging or vacuum-assisted emptying and post-purging to clear the residual process reaction gas in the furnace chamber, ensure that there is no or only a small amount of process reaction gas in the heating area where the heater is located, form an inert gas protective atmosphere, complete the inert gas purging operation in the heating area, and the inert gas enters the deposition area formed inside the graphite paper from the heating area through the gap between the nozzle insulation sleeve and the heat-conducting tube assembly, and finally flows out of the furnace chamber from the process tail gas outlet;

[0024] Step 2: Keep the inert gas nozzle open continuously, open the process gas nozzle, inject process gas through the process gas nozzle, monitor the inert gas pressure gauge, process tail gas pressure counter value, adjust the inert gas pressure regulating valve and process gas pressure regulating valve, ensure that the inert gas pressure value in the heating area is higher than the process gas pressure value in the deposition area, prevent the process gas from diffusing to the heater in the heating area, and take the process gas as the benchmark, the pressure value of the inert gas is higher than the normal pressure value of the process gas;

[0025] Step 3: After a period of time in step 2, the inert gas purge in the heating area and the process gas purge in the deposition area are completed to form a stable and uniform gas circuit. The inert protective gas flow rate is smaller than the process reaction gas flow rate to prevent the inert gas from diluting the process gas concentration and affecting the normal production of the CVD process.

[0026] Step 4: Turn on the heater electrode to start heating the heater. The heat of the heater is transferred to the insulation tube composed of the lower insulation felt, the main furnace chamber insulation felt, the upper insulation felt, the upper heat-conducting tube cover, the heat-conducting tube body and the lower heat-conducting tube cover through thermal radiation and inert gas heat conduction. Among them, since the lower insulation felt, the main furnace chamber insulation felt and the upper insulation felt are made of materials with low thermal conductivity and high temperature resistance, the heat is prevented from being transferred to the lower furnace cover, the main furnace chamber body and the upper furnace cover, and the heat preservation effect is achieved. The upper heat-conducting tube cover, the heat-conducting tube body and the lower heat-conducting tube cover are made of materials with high thermal conductivity and high temperature resistance. The heat energy is diffused to the graphite paper through the upper heat-conducting tube cover, the heat-conducting tube body and the lower heat-conducting tube cover to form a uniform heating body. The heat of the graphite paper is finally transferred to the product through thermal radiation and process gas heat, ensuring that the deposition area where the product is located reaches a temperature environment suitable for the CVD reaction;

[0027] Step 5: The heater and the insulation felt are protected by inert gas to prevent process gas from entering the heater, the lower insulation felt, the main furnace chamber insulation felt and the upper insulation felt, so that the heater, the lower insulation felt, the main furnace chamber insulation felt and the upper insulation felt are not deposited. Under the isolation effect of graphite paper, the CVD deposition reaction is only carried out on the inside of the graphite paper and on the product, so that the upper cover of the heat-conducting tube, the main body of the heat-conducting tube and the lower cover of the heat-conducting tube are not deposited;

[0028] Step 6: After a CVD production cycle is completed, only the graphite paper on the inner side of the upper cover of the heat-conducting tube, the main body of the heat-conducting tube and the lower cover of the heat-conducting tube need to be replaced. There is no need to replace the heater, lower insulation felt, main furnace chamber insulation felt and upper insulation felt, as well as the upper cover of the heat-conducting tube, the main body of the heat-conducting tube and the lower cover of the heat-conducting tube. This reduces the maintenance workload, reduces production costs and improves production efficiency.

[0029] The beneficial effects of the present invention are as follows: by adding a heat-conducting tube component and graphite paper with a high thermal conductivity structure, the heater and the product are isolated in two areas, so that the product is placed in the high-temperature reaction deposition area, and the heater and the thermal insulation felt component are isolated outside the deposition area to form a separate heating area. At the same time, the area of ​​the heating element is improved, and the uniformity of the CVD thermal field is improved. The heat energy is radiated through the heat-conducting tube component to effectively form a uniform thermal field space, ensure the temperature control accuracy, and improve the SIC product yield. By introducing inert gas into the heating area to prevent process gas from entering the vicinity of the heater, deposition reaction conditions are prevented from occurring on the heater and the thermal insulation felt component, the service life of the heater and the thermal insulation felt component is increased, maintenance costs are reduced, and product production efficiency is improved. By increasing the service life of the heater and the thermal insulation felt component, while reducing the loss of consumables, the manpower and time costs caused by the frequent replacement of heaters, thermal insulation felt components and debugging of phase difference resistors in the existing solution are also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1Shown is a schematic diagram of the cross-sectional structure of the heater of the present invention for preventing deposition and improving the temperature uniformity of the thermal field;

[0031] Figure 2 The structure of the heater of the present invention for preventing deposition and improving the temperature uniformity of the thermal field is presented. Figure 1 Enlarged structural diagram at point A in the middle.

[0032] Explanation of the reference numerals: 1. lower furnace cover; 2. lower insulation felt; 3. main furnace chamber body; 4. main furnace chamber insulation felt; 5. inert gas pressure gauge; 6. upper furnace cover; 7. upper insulation felt; 8. inert gas nozzle; 9. upper cover of heat-conducting tube; 10. process gas nozzle; 11. nozzle insulation sleeve; 12. heater; 13. heat-conducting tube body; 14. main furnace chamber heat-conducting tube support plate; 15. lower cover of heat-conducting tube; 16. product; 17. process exhaust gas pressure gauge; 18. inert gas pressure regulating valve; 19. process gas pressure regulating valve; 20. graphite paper. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] See also Figure 1-Figure 2 The present invention provides an embodiment: a structure for preventing heater deposition and improving temperature uniformity of thermal field, comprising a furnace / chamber body, a heat insulation felt assembly, a heater 12, a heat conduction tube assembly, a main furnace chamber heat conduction tube support plate 14, a gas path nozzle and a pressure detection device;

[0035] The furnace / chamber body comprises a lower furnace cover 1, a main furnace chamber body 3 and an upper furnace cover 6; the main furnace chamber body 3 and the upper furnace cover 6 are sequentially mounted on the upper end of the lower furnace cover 1; the lower furnace cover 1, the main furnace chamber body 3 and the upper furnace cover 6 are used to provide a closed space required for CVD reaction;

[0036] The insulation felt assembly includes a lower insulation felt 2, a main furnace chamber insulation felt 4 and an upper insulation felt 7; the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7 are respectively installed on the inner sides of the lower furnace cover 1, the main furnace chamber body 3 and the upper furnace cover 6;

[0037] The heat-conducting tube assembly includes a heat-conducting tube upper cover 9, a heat-conducting tube body 13 and a heat-conducting tube lower cover 15; the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 are sequentially installed at the lower end of the heat-conducting tube upper cover 9; the heat-conducting tube body 13 is connected to the main furnace chamber body 3 through the main furnace chamber heat-conducting tube support plate 14; the heat-conducting tube assembly is installed inside the furnace / chamber body, and is used to transfer the heat energy of the heater 12; the inside of the heat-conducting tube assembly is a deposition area, and is used to perform a CVD deposition reaction on the product 16 inside;

[0038] The graphite paper 20 is installed on the inner wall of the heat-conducting cylinder by using graphite nails or molybdenum nails to transfer the heat energy of the heat-conducting cylinder assembly and provide the high-temperature environment required for the CVD reaction; the graphite paper 20 isolates the heat-conducting cylinder assembly from the reaction gas, and the inner side of the graphite paper 20 is a deposition area for performing a CVD deposition reaction on the product 16 inside;

[0039] The gas path nozzle includes an inert gas nozzle 8, a process gas nozzle 10 and a nozzle insulation sleeve 11; the process gas nozzle 10 is installed with the nozzle insulation sleeve 11 when passing through the heating area formed by the inner side of the insulation felt assembly and the outer side of the heat-conducting tube assembly; the inert gas nozzle 8 is installed on the furnace / chamber body for introducing inert protective gas;

[0040] The pressure detection device includes an inert gas pressure gauge 5, a process tail gas pressure gauge 17, an inert gas pressure regulating valve 18 and a process gas pressure regulating valve 19; the inert gas pressure gauge 5 is connected to the heating area; the process tail gas pressure gauge 17 is connected to the deposition area; the inert gas pressure gauge 5 and the process tail gas pressure gauge 17 are used to monitor the pressure values ​​of the inert gas and the process gas; the inert gas pressure regulating valve 18 and the process gas pressure regulating valve 19 are used to adjust the pressure values ​​of the inert gas and the process tail gas;

[0041] The heater 12 is installed inside the thermal insulation felt assembly to provide thermal energy required for the CVD reaction.

[0042] See also Figure 1-Figure 2 In this embodiment, the heat-conducting tube assembly can be of an integrated type or a combined type; the heat-conducting tube assembly in the furnace / chamber body is used to separate the heater 12 and the product 16, and the number of furnace / chamber bodies is not limited, and the interior of the furnace / chamber body is divided into one or more heating areas and deposition areas; there is an installation gap between the nozzle insulation sleeve 11 and the main furnace chamber body 3, which is used to connect the heating area and the deposition area; the number and air intake direction of the inert gas nozzle 8 and the process gas nozzle 10 are not limited; the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7 are made of materials with low thermal conductivity and high temperature resistance, preferably cured felt; the lower furnace cover 1, the main furnace chamber body 3 and the upper furnace cover 6 are made of materials with high thermal conductivity and high temperature resistance.

[0043] In this embodiment, the inert gas nozzle 8 and the process gas nozzle 10 can enter from the side of the furnace / chamber body, or from the top, bottom, or the middle of the furnace / chamber body; the inert protective gas in the heating area can enter the deposition area from the gap between the process gas nozzle 10 and the heat-conducting tube assembly, or an inert gas inlet hole can be separately opened from the heat-conducting tube assembly, or a one-way valve and similar devices can be installed; a pressure regulating valve and a pressure gauge are used to monitor and regulate the pressure relationship between the protective gas and the process gas, and can also be replaced by other pressure reducing valves, overflow valves, etc.; the process gas nozzle 10 passes through the heating area where the heater 12 is located. In order to protect the gas transmitted inside the process gas nozzle 10 from being affected by high temperature before entering the deposition area to cause CVD deposition reaction, a nozzle insulation sleeve 11 is used for protection, and other devices that can achieve the same effect can be used, such as inert gas isolation;

[0044] A method for preventing heater deposition and improving thermal field temperature uniformity includes the structure for preventing heater deposition and improving thermal field temperature uniformity as described above, and the steps are as follows:

[0045] Step 1: Open the inert gas nozzle 8, inject inert gas into the heating area formed by the inner side of the thermal insulation felt assembly and the outer side of the heat-conducting tube assembly through the inert gas nozzle 8, open the process tail gas valve, and use inert gas purging or vacuum-assisted emptying and post-purging to clear the residual process reaction gas in the furnace chamber, ensure that there is no or only a small amount of process reaction gas in the heating area where the heater 12 is located, form an inert gas protective atmosphere, complete the inert gas purging operation in the heating area, and the inert gas enters the deposition area formed inside the graphite paper 20 from the heating area through the gap between the nozzle insulation sleeve 11 and the heat-conducting tube assembly, and finally flows out of the furnace chamber from the process tail gas outlet;

[0046] Step 2: Keep the inert gas nozzle 8 open continuously, open the process gas nozzle 10, inject process gas through the process gas nozzle 10, and adjust the inert gas pressure regulating valve 18 and the process gas pressure regulating valve 19 by monitoring the values ​​of the inert gas pressure gauge 5 and the process tail gas pressure gauge 17 to ensure that the inert gas pressure value in the heating area is higher than the process gas pressure value in the deposition area, so as to prevent the process gas from diffusing to the heater 12 in the heating area. Based on the process gas, the pressure value of the inert gas introduced should be higher than that of the process gas.

[0047] Step 3: After a period of time in step 2, the inert gas purge in the heating area and the process gas purge in the deposition area are completed to form a stable and uniform gas circuit. The inert protective gas flow rate is smaller than the process reaction gas flow rate to prevent the inert gas from diluting the process gas concentration and affecting the normal production of the CVD process.

[0048] Step 4: Turn on the heater 12 electrode to start heating the heater 12. The heat of the heater 12 is transmitted to the lower insulation felt 2, the main furnace chamber insulation felt 4, the upper insulation felt 7, the heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 through heat radiation and inert gas heat conduction. Among them, since the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7 are made of materials with low thermal conductivity and high temperature resistance, the heat is prevented from being transmitted to the lower furnace cover 1, the main furnace chamber body 3 and the upper insulation felt 7. The heat is transferred outside the furnace cover 6 to achieve heat preservation effect. The heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 are made of materials with high thermal conductivity and high temperature resistance. The heat energy is diffused to the graphite paper 20 through the heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 to form a uniform heating body. The heat of the graphite paper 20 is finally transferred to the product 16 through thermal radiation and process gas heat, ensuring that the deposition area where the product is located reaches a temperature environment suitable for CVD reaction;

[0049] Step 5: The heater 12 and the insulation felt are protected by inert gas to prevent process gas from entering the heater 12, the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7, so that the heater 12, the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7 are not deposited. Under the isolation effect of the graphite paper 20, the CVD deposition reaction is only carried out on the inside of the graphite paper 20 and the product 16, so that the heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 are not deposited;

[0050] Step 6: After a CVD production cycle is completed, only the graphite paper 20 on the inner side of the heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 needs to be replaced, and there is no need to replace the heater 12, the lower insulation felt 2, the main furnace chamber insulation felt 4 and the upper insulation felt 7, as well as the heat-conducting tube upper cover 9, the heat-conducting tube body 13 and the heat-conducting tube lower cover 15 and other components, thereby reducing the maintenance workload, reducing the production cost and improving the production efficiency.

[0051] Through the above steps, the heater 12 and the product 16 are isolated in two areas by adding a heat-conducting tube assembly with a high thermal conductivity structure and graphite paper 20, so that the product 16 is placed in the high-temperature reaction deposition area, and the heater 12 and the thermal insulation felt assembly are isolated outside the deposition area. The heat energy is radiated through the heat-conducting tube assembly, which can effectively form a uniform thermal field space. By introducing inert gas into the heating area to prevent the process gas from entering the vicinity of the heater 12, the deposition reaction conditions on the heater 12 and the thermal insulation felt assembly are prevented, the service life of the heater 12 and the thermal insulation felt assembly is increased, the maintenance cost is reduced, and the production efficiency of the product 16 is improved to solve the problem of the heater 12 and the thermal insulation felt assembly being coated.

[0052] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A structure for preventing heater deposition and improving thermal field temperature uniformity, comprising a furnace / chamber body, a thermal insulation felt assembly, a heater (12), a heat-conducting tube assembly, a main furnace chamber heat-conducting tube support plate (14), a gas path nozzle and a pressure detection device; characterized in that: The furnace / chamber body comprises a lower furnace cover (1), a main furnace chamber body (3) and an upper furnace cover (6); the main furnace chamber body (3) and the upper furnace cover (6) are sequentially mounted on the upper end of the lower furnace cover (1); the lower furnace cover (1), the main furnace chamber body (3) and the upper furnace cover (6) are used to provide a closed space required for a CVD reaction; The thermal insulation felt assembly comprises a lower thermal insulation felt (2), a main furnace chamber thermal insulation felt (4) and an upper thermal insulation felt (7); the lower thermal insulation felt (2), the main furnace chamber thermal insulation felt (4) and the upper thermal insulation felt (7) are respectively installed on the inner sides of the lower furnace cover (1), the main furnace chamber body (3) and the upper furnace cover (6); The heat-conducting tube assembly comprises a heat-conducting tube upper cover (9), a heat-conducting tube body (13) and a heat-conducting tube lower cover (15); the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) are sequentially mounted on the lower end of the heat-conducting tube upper cover (9); the heat-conducting tube body (13) is connected to the main furnace chamber body (3) via a main furnace chamber heat-conducting tube support plate (14); The heat transfer tube assembly is installed inside the furnace / chamber body and is used to transfer the heat energy of the heater (12); The graphite paper (20) is installed on the inner wall of the heat-conducting tube by using graphite nails or molybdenum nails to transfer the heat energy of the heat-conducting tube assembly and provide the high-temperature environment required for the CVD reaction; the graphite paper (20) isolates the heat-conducting tube assembly from the reaction gas, and the inner side of the graphite paper (20) is a deposition area for performing a CVD deposition reaction on the product (16) inside; The gas path nozzle comprises an inert gas nozzle (8), a process gas nozzle (10) and a nozzle heat insulation sleeve (11); the process gas nozzle (10) is installed with the nozzle heat insulation sleeve (11) when passing through the heating area formed by the inner side of the heat insulation felt assembly and the outer side of the heat conduction tube assembly; the inert gas nozzle (8) is installed on the furnace / chamber body and is used to introduce inert protective gas; The pressure detection device comprises an inert gas pressure gauge (5), a process tail gas pressure gauge (17), an inert gas pressure regulating valve (18) and a process gas pressure regulating valve (19); the inert gas pressure gauge (5) is connected to the heating area; the process tail gas pressure gauge (17) is connected to the deposition area; the inert gas pressure gauge (5) and the process tail gas pressure gauge (17) are used to monitor the pressure values ​​of the inert gas and the process gas; the inert gas pressure regulating valve (18) and the process gas pressure regulating valve (19) are used to adjust the pressure values ​​of the inert gas and the process tail gas; The heater (12) is installed inside the thermal insulation felt assembly and is used to provide thermal energy required for the CVD reaction.

2. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 1, characterized in that: The heat-conducting tube assembly can be of an integrated type or a combined type.

3. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 2, characterized in that: The heat-conducting tube assembly in the furnace / chamber body is used to separate the heater (12) and the product (16). The number of furnace / chamber bodies is not limited, and the interior of the furnace / chamber body is divided into one or more heating areas and deposition areas.

4. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 3, characterized in that: There is an installation gap between the nozzle insulation sleeve (11) and the heat-conducting tube body (13), which is used to connect the heating area and the deposition area.

5. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 4, characterized in that: The number and gas inlet direction of the inert gas nozzles (8) and process gas nozzles (10) are not limited.

6. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 5, characterized in that: The lower insulation felt (2), the main furnace chamber insulation felt (4) and the upper insulation felt (7) are made of materials with low thermal conductivity and high temperature resistance.

7. The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 6, characterized in that: The heat-conducting tube upper cover (9), the heat-conducting tube main body (13) and the heat-conducting tube lower cover (15) are made of materials with high thermal conductivity and high temperature resistance.

8. A method for preventing heater deposition and improving thermal field temperature uniformity, characterized in that The structure for preventing heater deposition and improving thermal field temperature uniformity according to claim 7 comprises the following steps: Step 1: Open the inert gas nozzle (8), inject inert gas into the heating area formed by the inner side of the thermal insulation felt assembly and the outer side of the heat-conducting tube assembly through the inert gas nozzle (8), open the process tail gas valve, and use inert gas purging or vacuum-assisted emptying and post-purging to clear the residual process reaction gas in the furnace chamber, ensure that there is no or only a small amount of process reaction gas in the heating area where the heater (12) is located, form an inert gas protective atmosphere, complete the inert gas purging operation in the heating area, and the inert gas enters the deposition area formed inside the graphite paper (20) from the heating area through the gap between the nozzle thermal insulation sleeve (11) and the heat-conducting tube assembly, and finally flows out of the furnace chamber from the process tail gas outlet; Step 2: Keep the inert gas nozzle (8) open continuously, open the process gas nozzle (10), and inject the process gas into the deposition area through the process gas nozzle (10). By monitoring the values ​​of the inert gas pressure gauge (5) and the process tail gas pressure gauge (17), adjust the inert gas pressure regulating valve (18) and the process gas pressure regulating valve (19) to ensure that the inert gas pressure value in the heating area is higher than the process gas pressure value in the deposition area, and prevent the process gas from diffusing to the periphery of the heater (12) in the heating area. Based on the process gas, the pressure value of the inert gas introduced is higher than that of the process gas. Step 3: After a period of time in step 2, the inert gas purge in the heating area and the process gas purge in the deposition area are completed to form a stable and uniform gas circuit. The inert protective gas flow rate is smaller than the process reaction gas flow rate to prevent the inert gas from diluting the process gas concentration and affecting the normal production of the CVD process. Step 4: Connect the heater (12) electrode to start heating the heater (12). The heat of the heater (12) is transferred to the lower insulation felt (2), the main furnace chamber insulation felt (4), the upper insulation felt (7), the heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) through heat radiation and inert gas heat conduction. The lower insulation felt (2), the main furnace chamber insulation felt (4) and the upper insulation felt (7) are made of materials with low thermal conductivity and high temperature resistance, which prevents the heat from being transferred to the lower furnace cover (1), the main furnace chamber body ( 3) and the upper furnace cover (6) to achieve a heat preservation effect. The heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) are made of materials with high thermal conductivity and high temperature resistance. The heat energy is diffused to the graphite paper (20) through the heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) to form a uniform heating body. The heat of the graphite paper (20) is finally transferred to the product (16) through thermal radiation and process gas heat, ensuring that the deposition area where the product is located reaches a temperature environment suitable for the CVD reaction; Step 5: The heater (12) and the thermal insulation felt are protected by inert gas to prevent process gas from entering the periphery of the heater (12), the lower thermal insulation felt (2), the main furnace chamber thermal insulation felt (4) and the upper thermal insulation felt (7), so that the heater (12), the lower thermal insulation felt (2), the main furnace chamber thermal insulation felt (4) and the upper thermal insulation felt (7) are not deposited. Under the isolation effect of the graphite paper (20), the CVD deposition reaction is only carried out on the inner side of the graphite paper (20) and on the product (16), so that the heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) are not deposited either. Step 6: After a CVD production cycle is completed, only the graphite paper (20) on the inner side of the heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) needs to be replaced, and there is no need to replace the heater (12), the lower insulation felt (2), the main furnace chamber insulation felt (4) and the upper insulation felt (7) as well as the heat-conducting tube upper cover (9), the heat-conducting tube body (13) and the heat-conducting tube lower cover (15) and other components, thereby reducing the maintenance workload, reducing the production cost and improving the production efficiency.

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