CN118162419A - Cleaning process of chemical vapor deposition furnace tube and furnace tube with cleaning function - Google Patents

Abstract

The present invention provides a cleaning process for a chemical vapor deposition furnace tube and a furnace tube with a cleaning function, comprising the following steps: sealing a cavity with a layer to be cleaned inside, setting the environmental conditions inside the cavity; introducing a cleaning gas from the bottom of the cavity to clean the layer to be cleaned in the cavity; wherein setting the environmental conditions inside the cavity includes: controlling the temperature inside the cavity from the bottom to the top in a gradient from high to low. A cleaning process for a chemical vapor deposition furnace tube and a furnace tube with a cleaning function of the present invention increase the temperature at the bottom of the furnace tube cavity, accelerate the thermal decomposition rate of the cleaning gas at the bottom of the cavity, make the cleaning rate of the entire cavity tend to be consistent, thereby improving the cleaning efficiency of the entire cavity, shortening the cleaning time of the cavity, improving the problem of damage caused by excessive cleaning of the top of the cavity due to the need to extend the time for cleaning the bottom of the cavity, and extending the service life of the cavity.

Description

Cleaning process of chemical vapor deposition furnace tube and furnace tube with cleaning function

Technical Field

The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a cleaning process for a chemical vapor deposition furnace tube and a furnace tube with a cleaning function.

Background technique

In the semiconductor manufacturing process, the maintenance and cleaning of the machine is a very important link. In the chemical vapor deposition process, the reaction gas source silane enters the reaction chamber in gaseous form. Under the action of high temperature, silane decomposes to generate polysilicon, silicon nitride and other products deposited on the wafer in the reaction chamber. In this process, the product is not only deposited on the surface of the wafer, but also deposited anywhere in the cavity, such as various areas of the inner cavity in the vertical furnace tube and the inner side wall of the outer cavity and the gap between the inner cavity and the outer cavity. In order to prevent the long-term deposition of the product from affecting the quality of wafer processing, it is necessary to clean the reaction chamber regularly. In this field, cleaning gas is generally used as a cleaning agent. The principle is to use the cleaning gas to produce a strong oxidizing product after high-temperature decomposition, which reacts with the product to be removed in the cavity to generate gas and be pumped away, thereby achieving the purpose of cleaning.

In the actual process, it is found that after the furnace tube cavity is cleaned a certain number of times, the top of the furnace tube is damaged, resulting in a decrease in the yield rate of wafer processing. At present, in order to solve this problem, the selected treatment method is: after the furnace tube cavity is cleaned a certain number of times, the furnace tube cavity is replaced, but this method has high maintenance costs, labor costs, material costs, etc.

Summary of the invention

Therefore, the purpose of the present invention is to propose a cleaning process for a chemical vapor deposition furnace tube and a furnace tube with a cleaning function, which can reduce the degree of damage to the top of the cavity, extend the service life of the furnace tube cavity, and save labor costs, maintenance costs and material costs.

In a first aspect, the present invention provides a chemical vapor deposition furnace tube cleaning process, comprising the following steps:

A cavity having a layer to be cleaned is sealed, and environmental conditions inside the cavity are set;

A cleaning gas is introduced from the bottom of the cavity to clean the layer to be cleaned in the cavity;

The setting of the internal environmental conditions of the cavity includes: the temperature inside the cavity is controlled from high to low gradient from bottom to top.

According to a specific implementation of an embodiment of the present application, the cleaning gas is a fluorinated gas.

According to a specific implementation of the embodiment of the present application, setting the internal environmental conditions of the cavity also includes: setting the internal pressure of the cavity to 0.1-1.2 torr.

According to a specific implementation of the embodiment of the present application, when the temperature inside the cavity is controlled from high to low gradient from bottom to top, the temperature at the bottom of the cavity is 15-30° C. higher than the temperature at the top of the cavity.

According to a specific implementation of the embodiment of the present application, the cleaning process further includes: after the layer to be cleaned in the cavity is cleaned, continuously introducing the cleaning gas for a period of time to completely clean the layer to be cleaned.

According to a specific implementation of the embodiment of the present application, after the layer to be cleaned in the cavity is cleaned, the cleaning gas is continuously introduced for 3-5 minutes.

According to a specific implementation of an embodiment of the present application, the cleaning process further includes: after the layer to be cleaned in the cavity is cleaned, an inert gas or nitrogen is continuously introduced into the cavity for a period of time to remove by-products in the cavity.

According to a specific implementation of the embodiment of the present application, the flow rate of the inert gas or nitrogen introduced into the cavity is 1.5SL-2SL, and the continuous introduction time is 3-5min.

In a second aspect, the present invention provides a chemical vapor deposition furnace tube with a cleaning function, comprising:

At least two temperature control modules for heating the closed furnace tube cavity;

A control module, wherein the control module is configured to: control the temperature control module to adjust the environmental conditions inside the cavity, and

Controlling the cleaning gas to flow into the cavity from the bottom of the cavity to clean the layer to be cleaned in the cavity;

Wherein, the environmental conditions include: the temperature inside the cavity is controlled from high to low gradient from bottom to top.

According to a specific implementation of the embodiment of the present application, each of the temperature control modules includes at least one heating unit.

According to a specific implementation of the embodiment of the present application, the control module is further configured to control the pressure control module to adjust the environmental conditions inside the cavity, and the environmental conditions include a pressure inside the cavity of 0.1-1.2 torr.

The cleaning process of the chemical vapor deposition furnace tube and the furnace tube with cleaning function of the present invention increase the temperature of the bottom of the furnace tube cavity, accelerate the thermal decomposition rate of the cleaning gas at the bottom of the cavity, and make the cleaning rate of the entire cavity tend to be consistent. This improves the cleaning efficiency of the cavity as a whole, shortens the cleaning time of the cavity, and also improves the problem of damage caused by excessive cleaning of the top of the cavity due to the need to extend the time for cleaning the bottom of the cavity. The present invention extends the service life of the cavity, ensures the quality of wafer processing, and reduces labor costs, maintenance costs and material costs. Other features and advantages of the present invention will be explained in the subsequent description, and partly become apparent from the description, or can be understood through the implementation of the present invention. The objects and other advantages of the present invention can be achieved and obtained through the structures indicated in the description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 shows a schematic cross-sectional structure diagram of a furnace tube device;

FIG2 is a schematic diagram showing a cleaning process flow of a chemical vapor deposition furnace tube according to an embodiment of the present invention; and

FIG. 3 shows a schematic structural diagram of a chemical vapor deposition furnace tube with a cleaning function according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Before introducing the cleaning process of the chemical vapor deposition furnace tube of the present invention, the structure of the furnace tube device is first understood. Please refer to Figure 1, which shows a schematic diagram of the cross-sectional structure of the furnace tube device. As shown in Figure 1, the furnace tube device includes a furnace body 100 and a cavity, and the cavity includes an outer cavity 200 and an inner cavity 300. The inner cavity 300 is vertically arranged inside the furnace body 100, and the outer cavity 200 is arranged outside the inner cavity 300. The outer cavity 200 is also vertically arranged inside the furnace body 100, and a gap is formed between the inner cavity 300 and the outer cavity 200, wherein the top of the outer cavity 200 is closed, and the actual structure of the inner cavity 300 is a tubular structure, and the internal space of the outer cavity 200 and the inner cavity 300 together constitute the cavity. A temperature control area is provided on the side wall of the furnace body 100. Because the structural size of the furnace tube device is very large, it is easy for the temperature control area to produce uneven conditions in which the temperature of some areas is too high and the temperature of some areas is too low during the heating of the cavity. However, when the wafer is subjected to chemical vapor deposition, high requirements are placed on temperature accuracy and uniformity. During the manufacturing process, in order to control the temperature of each area of the cavity to be uniform, and thus more accurately control the overall temperature of the cavity to be consistent, the temperature control area is generally divided into five heating units, namely the first heating unit 400, the second heating unit 500, the third heating unit 600, the fourth heating unit 700 and the fifth heating unit 800. During the process, the furnace tube is heated to the same target temperature by controlling multiple heating units at the same time, thereby controlling the temperature inside the furnace tube cavity to be more uniform. Specifically, each heating unit includes a heater, a temperature sensor and a controller. During the heating process, the controller controls the heater to heat the cavity. At the same time, the temperature sensor monitors the temperature inside the cavity and transmits the monitored temperature data information to the controller in real time. Once the temperature in the cavity is detected to reach the preset target temperature, the controller immediately controls the heater to stop heating.

After the chemical vapor deposition process is completed on the wafer, when the cavity of the furnace tube needs to be cleaned, considering the need to cooperate with the structural characteristics of the existing furnace tube cavity, the general method is: by controlling multiple heating units to uniformly heat the cavity at the same temperature, the cleaning gas is then passed from the air inlet 201 at the bottom of the outer cavity 200 of the furnace tube device into the inner cavity 300, reaching the top of the inner cavity 300, and then through the gap between the inner cavity 300 and the outer cavity 200, and finally from the air outlet 202 at the bottom of the outer cavity 200. The cleaning gas is generally selected according to the layer to be cleaned. However, the inventor of the present application found that after a certain number of cleanings, the yield rate of wafer processing will decrease. After the inventor of the present application analyzed and found that after the furnace tube cavity is cleaned a certain number of times, the top will be over-cleaned and particles will be generated. During the wafer processing, the particles will affect the processing of the wafer. At present, in order to avoid the decrease of wafer yield due to this reason, the selected treatment method is: after the furnace tube cavity is cleaned a certain number of times, the furnace tube cavity is replaced, but this method has high maintenance costs, labor costs, material costs, etc. Therefore, the inventor of this case conducted research on this and proposed a cleaning process for chemical vapor deposition furnace tubes, which can reduce the degree of damage to the top of the cavity, extend the service life of the furnace tube cavity, and save labor costs, maintenance costs and material costs.

Please refer to Figure 2, which shows a schematic diagram of the cleaning process of the chemical vapor deposition furnace tube according to an embodiment of the present invention. As shown in Figure 2, the cleaning process of the chemical vapor deposition furnace tube according to the present invention includes the following steps:

Step S100: sealing a cavity having a layer to be cleaned therein, and setting environmental conditions inside the cavity.

Specifically, when closed, as shown in FIG. 1 , the outer cavity 200 is sleeved on the outside of the inner cavity 300, so that the inside of the cavity is a closed environment. The layer to be cleaned is a product deposited on other areas other than the surface of the wafer during the chemical vapor deposition process. In the embodiment of the present invention, the other areas include various areas of the inner cavity 300, the inner side wall of the outer cavity 200, and the gap between the inner cavity 300 and the outer cavity 200. Setting the internal environmental conditions of the cavity includes: the temperature inside the cavity is controlled from high to low gradient from bottom to top.

When the cleaning gas enters the bottom of the inner cavity 300, the reaction temperature is not reached due to the low temperature. Therefore, the cleaning gas is not immediately cleaned when it enters the inner cavity 300. The cleaning gas is continuously heated during the upward circulation process, and a partial thermal decomposition reaction will occur during the heating process. The reaction occurring during the cleaning process is exothermic, which will make the gas temperature at the top of the inner cavity 300 significantly higher than the gas temperature at the bottom of the inner cavity 300. During the cleaning process, the cleaning gas, such as chlorine trifluoride, will first be completely decomposed at the top of the inner cavity 300 and the upper position of the outer cavity 200 and produce enough fluorine gas to react with the layer to be cleaned in the furnace tube cavity first, and gradually extend to the bottom of the cavity. This easily leads to the cleaning of the top of the cavity starting first and cleaning first, and the bottom of the cavity starting to clean after the top of the cavity starts to clean for a period of time, which leads to the result that the top of the cavity has been cleaned, while the bottom of the cavity has not been cleaned. Therefore, in order to ensure that the bottom of the inner cavity 300 and the outer cavity 200 can also be cleaned, the cleaning time of the entire cleaning procedure can only be extended. In this way, it is inevitable that the top of the chamber will be damaged due to excessive cleaning. When the number of cleanings is sufficient, the impact of the damage to the top of the chamber will become prominent, resulting in a decrease in the yield rate of wafer processing.

Therefore, in the actual cleaning process, the embodiment of the present invention selects different cleaning gases according to different products generated by different chemical vapor deposition processes; then, according to the actual reaction temperature of the cleaning gas, the multiple heating units in the temperature control area of the furnace body are divided into regions, and then the heating temperature of each region of the furnace body is selected and set. When setting, the temperature control area of the furnace body is divided into regions, including the temperature inside the cavity being controlled from high to low gradient from the bottom to the top.

For example, in combination with the structure of the furnace tube device, the temperature control area of the furnace body is divided into regions. When the temperature control area is divided into the bottom, the middle and the top, the bottom is the fourth heating unit 700 and the fifth heating unit 800, the middle is the second heating unit 500 and the third heating unit 600, and the top is the first heating unit 400. The specific setting method is: the temperature at the bottom of the cavity is 10-20°C higher than the temperature in the middle of the cavity, and the temperature in the middle of the cavity is 5-10°C higher than the temperature at the top of the cavity. Inside the bottom, the temperature remains consistent, as is the case with the inside of the middle and the top.

In another embodiment, the temperature control area of the furnace body is divided into regions in combination with the structure of the furnace tube device. When the temperature control area is divided into the bottom and the top, the bottom is the fourth heating unit 700 and the fifth heating unit 800, and the top is the first heating unit 400, the second heating unit 500 and the third heating unit 600. The specific setting method is: the temperature at the bottom of the cavity is 15-30°C higher than the temperature at the top of the cavity. The temperature inside the bottom and the top is kept consistent.

Furthermore, setting the internal environmental conditions of the cavity also includes: setting the internal pressure of the cavity to 0.1-1.2 torr.

Step S200: introducing a cleaning gas from the bottom of the cavity, and using a product generated by a decomposition reaction of the cleaning gas to clean the layer to be cleaned in the cavity. Exemplarily, the product is fluorine gas.

Furthermore, the flow rate of the cleaning gas introduced into the chamber is 1.5SL-2SL.

Preferably, the cleaning process also includes step S300: after the layer to be cleaned in the cavity is cleaned, continue to introduce cleaning gas into the cavity for a period of time to further ensure that the layer to be cleaned is completely cleaned. Exemplarily, the time for continuously introducing cleaning gas in the embodiment of the present invention is 3-5 minutes, and the flow rate can remain unchanged. It is worth noting that the time required for cleaning of the layer to be cleaned in the cavity can be judged empirically, and the time when cleaning is reached can be directly judged as being cleaned. The temperature change in the cavity can also be monitored in real time by the temperature sensor in the heating unit for judgment. When the cleaning gas is continuously introduced and the temperature monitored by the temperature sensor is consistent with the temperature controlled by the temperature control area, that is, when the detected temperature is equal to the temperature heated by the heating unit in the temperature control area, it can be judged as being clean. The reason for this judgment is that when the cleaning gas cleans the layer to be cleaned, the reaction that occurs is an exothermic reaction. The specific reaction will be explained in detail below. As long as the layer to be cleaned is not cleaned thoroughly, the cleaning gas will continue to react with the layer to be cleaned, and the temperature inside the cavity detected by the temperature sensor will continue to be higher than the temperature heated by the heating unit of the temperature control area, until the temperature inside the cavity detected by the temperature sensor is equal to the temperature heated by the heating unit of the temperature control area, indicating that the cleaning reaction no longer occurs and the layer to be cleaned is completely cleaned.

Preferably, the cleaning process further comprises step S400: after continuously introducing the cleaning gas for a period of time, continuously introducing an inert gas or nitrogen into the cavity for a period of time to remove byproducts in the cavity and complete the cleaning process. Exemplarily, in an embodiment of the present invention, nitrogen is selected. Furthermore, in an embodiment of the present invention, the flow rate of nitrogen introduced into the cavity is 1.5SL-2SL, and the continuous introduction time is 3-5min.

In this field, fluorinated gases are usually selected as cleaning gases for chemical vapor deposition products, among which chlorine trifluoride is particularly commonly used. Chlorine trifluoride is relatively stable at room temperature, and its activity is similar to that of chlorine. However, the activity of chlorine trifluoride increases rapidly when heated, and it begins to decompose at a temperature of 250°C, and the products are chlorine fluoride and fluorine gas. This reaction will release a large amount of heat, and the heat generated will further aggravate the decomposition of chlorine trifluoride, thereby producing more fluorine gas. When the temperature reaches 600°C, chlorine trifluoride is completely decomposed. The fluorine gas produced by the reaction can react with chemical vapor deposition products such as polysilicon, silicon nitride, silicon carbon nitrogen, etc. in the cavity to generate silicon tetrafluoride gas and be pumped away, thereby achieving the purpose of cleaning.

The embodiment of the present invention provides a chemical vapor deposition furnace tube with a cleaning function to match the implementation of the cleaning process of the above-mentioned chemical vapor deposition furnace tube. Please refer to Figure 3, which shows a schematic diagram of the structure of the chemical vapor deposition furnace tube with a cleaning function in an embodiment of the present invention. As shown in Figure 3, the chemical vapor deposition furnace tube 301 with a cleaning function includes:

At least two temperature control modules 3012 for heating the closed furnace tube cavity 3011;

The control module 3014 is configured to: control the temperature control module 3012 to adjust the environmental conditions inside the cavity 3011, and

Controlling the cleaning gas to flow into the cavity 3011 from the bottom of the cavity 3011 to clean the layer to be cleaned in the cavity 3011;

The environmental conditions include: the temperature inside the cavity 3011 is controlled from high to low gradient from bottom to top.

Furthermore, each temperature control module 3012 includes at least one heating unit 30121 .

Furthermore, the control module 3014 is also configured to control the pressure control module 3013 to adjust the environmental conditions inside the cavity 3011; the environmental conditions here specifically include: the pressure inside the cavity 3011 is 0.1-1.2 torr.

Next, the cleaning process of the chemical vapor deposition furnace tube according to the embodiment of the present invention is exemplarily described by taking a practical example of using chlorine trifluoride gas as a cleaning gas to clean a cavity having a polysilicon film.

Please refer to FIG. 1 . An embodiment of the present invention provides a cavity having a polysilicon film inside, and the entire cavity is enclosed. In this embodiment, the furnace body is provided with 5 heating units, which are respectively divided into the first heating unit 400, the second heating unit 500, the third heating unit 600, the fourth heating unit 700 and the fifth heating unit 800 from top to bottom. After the 5 heating units are divided into regions, each region can be accurately heated and temperature controlled, thereby achieving different temperature control of different regions of the cavity. The environmental conditions inside the cavity are established, and the environmental conditions include temperature conditions and pressure conditions. The temperature inside the cavity is controlled from high to low gradient from bottom to top. In the embodiment of the present invention, the temperature control area of the furnace body is divided into regions, and the temperature control area is divided into the bottom, the middle and the top. Specifically, the bottom is the fourth heating unit 700 and the fifth heating unit 800, the middle is the second heating unit 500 and the third heating unit 600, and the top is the first heating unit 400. The specific setting of the temperature condition is: the temperature of the bottom of the cavity is set to 400°C, that is, the temperature of the fourth heating unit 700 and the fifth heating unit 800 is set to 400°C; and the temperature of the bottom of the cavity is 15°C higher than the temperature of the middle of the cavity, that is, the temperature of the second heating unit 500 and the third heating unit 600 is set to 385°C; the temperature of the middle of the cavity is 15°C higher than the temperature of the top of the cavity, that is, the temperature of the first heating unit 400 is set to 370°C. In the embodiment of the present invention, the pressure condition inside the cavity is set to 1.0 torr.

Chlorine trifluoride is introduced into the inner cavity 300 from the gas inlet 201 set at the bottom of the outer cavity 200, and the flow rate is set to 1.75SL, and the fluorine gas generated by the decomposition reaction of chlorine trifluoride is used to clean the polysilicon in the cavity. The introduced chlorine trifluoride gas undergoes a decomposition reaction under high temperature conditions to generate chlorine fluoride and fluorine gas, and then the generated fluorine gas is used to clean the polysilicon layer in the cavity. The cleaning in the embodiment of the present invention refers to the use of fluorine gas and silicon to react to remove the polysilicon layer in the cavity. The reaction equations for the decomposition of chlorine trifluoride to generate fluorine gas and the removal of polysilicon by fluorine gas are: ClF ₃ →ClF+F ₂ ; Si+F ₂ →SiF ₄ ; the product SiF ₄ exists in the cavity in a gaseous state. The present invention introduces fluorinated gas into the cavity and uses fluorine gas to clean the polysilicon layer in the cavity until the polysilicon layer in the cavity is completely cleaned.

After cleaning, nitrogen is continuously filled for a period of time to remove the by-products in the cavity and complete the cleaning process. In an embodiment of the present invention, a vacuum device (not shown) is provided at the gas outlet 202 to extract the by-products in the cavity from the gap between the inner cavity 300 and the outer cavity 200 through the gas outlet 202. Since the chlorine trifluoride gas introduced from the bottom of the cavity produces fluorine gas and chlorine fluoride after decomposition, and the fluorine gas further reacts with silicon to generate silicon tetrafluoride gas, the main components of the by-products after the reaction are silicon tetrafluoride and chlorine fluoride. In order to ensure sufficient reaction, the polycrystalline silicon layer inside the furnace tube is cleaned, and after cleaning, chlorine trifluoride gas is continuously filled for 3-5 minutes to further ensure that the polycrystalline silicon film layer is completely cleaned and the cleaning effect is ensured, and then nitrogen is filled for 3-5 minutes to facilitate the extraction of by-products.

The present invention implements zone-by-zone heating of the furnace tube to achieve precise control of different temperatures in different zones, so that the cleaning efficiency of the entire cavity tends to be consistent, improving the problem of excessive cleaning and damage to the top of the cavity due to the need to extend the time for cleaning the cavity due to the initial temperature not meeting the standard, thereby extending the service life of the cavity, ensuring the quality of wafer processing and reducing costs.

Furthermore, by increasing the temperature at the bottom of the furnace tube cavity, the cleaning gas at the bottom of the cavity is promoted to quickly reach the reaction temperature, thereby increasing the decomposition rate of the cleaning gas and thus improving the cleaning efficiency of the cavity. Taking the thickness of the polysilicon thin layer in the cavity as 10 microns as an example, the time required for the existing cleaning process is about 130 minutes, while the time required for the cleaning process of the present invention is about 115 minutes.

Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (11)

1. A cleaning process for a chemical vapor deposition furnace tube is characterized by comprising the following steps of: the method comprises the following steps:

sealing a cavity with a layer to be cleaned inside, and setting the environmental conditions inside the cavity;

Introducing cleaning gas from the bottom of the cavity to clean the layer to be cleaned in the cavity;

wherein, the setting of the environmental conditions within the cavity comprises: the temperature inside the cavity is controlled from the bottom to the top in a gradient manner from high to low.

2. The process for cleaning a chemical vapor deposition furnace tube according to claim 1, wherein: the cleaning gas is a fluorinated gas.

3. The process for cleaning a chemical vapor deposition furnace tube according to claim 1, wherein: the setting of environmental conditions within the cavity further comprises:

the pressure inside the cavity is set to 0.1-1.2torr.

4. The process for cleaning a chemical vapor deposition furnace tube according to claim 1, wherein: when the temperature inside the cavity is controlled from bottom to top in a gradient manner from high to low, the temperature at the bottom of the cavity is 15-30 ℃ higher than the temperature at the top of the cavity.

5. The process for cleaning a chemical vapor deposition furnace tube according to claim 1, wherein: the cleaning process further comprises the following steps:

after the layer to be cleaned in the cavity is cleaned, continuously introducing cleaning gas for a period of time to enable the layer to be cleaned completely.

6. The process for cleaning a chemical vapor deposition furnace tube according to claim 5, wherein: after the layer to be cleaned in the cavity is cleaned, continuously introducing cleaning gas for 3-5min.

7. The process for cleaning a chemical vapor deposition furnace tube according to claim 1 or 5, wherein: the cleaning process further comprises the following steps:

after the layer to be cleaned in the cavity is cleaned, continuously introducing inert gas or nitrogen into the cavity for a period of time to remove byproducts in the cavity.

8. The process for cleaning a chemical vapor deposition furnace tube according to claim 7, wherein: and (3) introducing inert gas or nitrogen into the cavity at a flow rate of 1.5SL-2SL for 3-5min.

9. The utility model provides a chemical vapor deposition furnace tube with cleaning function which characterized in that: comprising the following steps:

at least two temperature control modules for heating and sealing the furnace tube cavity;

A control module configured to: controlling the temperature control module to adjust the environmental condition inside the cavity, and

Controlling cleaning gas to be introduced into the cavity from the bottom of the cavity so as to clean a layer to be cleaned in the cavity;

Wherein the environmental conditions include: the internal temperature of the cavity is controlled from the bottom to the top in a gradient manner from high to low.

10. The chemical vapor deposition furnace tube with cleaning function according to claim 9, wherein:

Each temperature control module at least comprises a heating unit.

11. The chemical vapor deposition furnace tube with cleaning function according to claim 9, wherein:

The control module is further configured to control the control module to adjust an environmental condition inside the cavity;

The environmental conditions include: the pressure in the cavity is 0.1-1.2torr.