Furnace tube with cleaning function and cleaning process of furnace tube

Abstract

The invention provides a furnace tube with a cleaning function and a furnace tube cleaning process. The furnace tube comprises a furnace body, a temperature control area is arranged on the side wall of the furnace body, and the method comprises the steps that a wafer boat and a heat preservation barrel are lifted into the furnace body, and the furnace body is closed and vacuumized; cleaning gas is introduced into the furnace body to clean the to-be-cleaned layer in the furnace body, and in the cleaning process, the heating temperature of a first temperature control area in the temperature control areas is controlled to be gradually reduced, so that the final target temperature of the first temperature control area at the end of cleaning is 5-10 DEG C lower than the initial target temperature at the beginning of cleaning, the first temperature control area corresponds to the upper area of the heat preservation barrel. The heating temperature of the first temperature control area corresponding to the upper area of the heat preservation barrel is controlled to be gradually reduced; and when the cleaning process is finished, the target temperature of the first temperature control area is lower than the initial target temperature of the temperature control area by 5-10 DEG C, so that the aims of protecting the insulation barrel, preventing particle pollution sources caused by over-etching during cleaning and guaranteeing the wafer processing quality are fulfilled.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor production equipment, and in particular relates to a furnace tube with a cleaning function and a furnace tube cleaning process. Background Art

[0002] The semiconductor manufacturing process involves many different steps to create complex semiconductor devices. Some processes, such as diffusion, often require high-temperature and long-term thermal treatment. Furnaces are commonly used in thin film deposition processes within these thermal treatments.

[0003] like Figure 1 、 Figure 2 As shown, Figure 1 Shows a schematic diagram of the furnace tube structure; Figure 2 The cross-sectional structural diagram of the furnace tube is shown. The furnace tube includes a furnace body 100, and a temperature control area 200 is provided on the side wall of the furnace body 100 to control the thermal field temperature inside the furnace body 100. A fixing part 300 is provided at the bottom of the furnace body 100, and an inner tube 400 and an outer tube 500 are provided inside the furnace body 100. The inner tube 400 is vertically arranged inside the furnace body 100, and the bottom of the inner tube 400 is fixed on the fixing part 300. The outer tube 500 is arranged outside the inner tube 400, and the bottom of the outer tube 500 is also fixed on the fixing part 300. A through hole is opened in the middle of the fixing part 300, which runs through from top to bottom, so that the crystal boat 600 and the heat preservation barrel 700 can enter and be removed from the inner tube 400. The crystal boat 600 is fixedly arranged directly above the heat preservation barrel 700, as shown in FIG. Figure 3 As shown, the heat preservation barrel 700 is composed of a plurality of fins, which are generally made of quartz material. The heat preservation barrel 700 is an integrated structure, and the fins are not detachable.

[0004] During the non-process period, the wafer boat 600 is generally located below the furnace body 100. When the process is required, the wafers are first placed on the wafer boat 600, and then the wafer boat 600 is raised from the bottom of the furnace body 100 to the inside of the inner tube 400 of the furnace body 100. At the same time, the heat preservation barrel 700 is also raised to the inside of the inner tube 400. A sealing cover 800 is provided at the bottom of the heat preservation barrel 700. When the wafer boat 600 and the heat preservation barrel 700 both reach the inside of the inner tube 400, the sealing cover 800 forms a seal with the bottom of the fixing part 300. At this time, a sealed space is formed inside the furnace body. The temperature control area 200 can adjust the thermal field of the sealed space to make the thermal field inside the furnace tube corresponding to the temperature control area 200 uniform and stable. Figure 1 and Figure 2As can be seen, the temperature control area 200 is divided into multiple temperature control zones to achieve more precise control over the overall temperature of the furnace body 100. The temperature control area 200 is generally divided into five heating units: a first heating unit 201, a second heating unit 202, a third heating unit 203, a fourth heating unit 204, and a fifth heating unit 205. During the process, the furnace body 100 is heated to the same target temperature by controlling multiple heating units simultaneously, thereby achieving more uniform temperature control within the furnace body 100. When the wafer boat 600 and the insulation barrel 700 rise into the inner tube 400, the upper area 701 of the insulation barrel 700 corresponds to the fifth heating unit 205 of the temperature control area 200, while the lower area 702 of the insulation barrel 700 is located outside the temperature control area 200. This design ensures that all wafers on the wafer boat 600 are exposed to a uniform and stable thermal field during the process, thereby promoting uniform thin film deposition.

[0005] After each thin film deposition process, the wafer boat 600 and the heat preservation barrel 700 need to be placed in the inner tube 400 to form a sealed space in the furnace body 100 again. The entire furnace body 100 is then etched and cleaned to remove the thin film deposition reactants produced by the previous thin film deposition process to ensure a clean environment for the next thin film deposition process. However, in actual process operations, it has been found that after a certain number of thin film deposition processes and cleanings, the portion of the heat preservation barrel 700 corresponding to the temperature control area 200 will be damaged. The surface of the fin corresponding to the temperature control area 200 is easily over-etched due to repeated exposure to high temperatures and repeated cleaning, resulting in a rough surface that is prone to particle generation and becomes a potential source of particle contamination. During the thin film deposition process, the reaction gas enters the inner tube 400 from the air inlet 301 provided on the fixing part 300, and is then transported upward in the inner tube 400, and then discharged from the exhaust port 302 provided on the fixing part 300 through the gap between the inner tube 400 and the outer tube 500. When the reaction gas is transported upward from the bottom of the inner tube 400, it is easy to carry the particle pollution source upward, and then fall on the surface of the wafer, resulting in a decrease in the yield rate of wafer processing during the thin film deposition process. In order to solve this problem, the current treatment method selected is: after the heat preservation barrel 700 has been cleaned and etched a certain number of times, the heat preservation barrel 700 is replaced, but the maintenance cost, labor cost, material cost, etc. of this method are all relatively large. Summary of the Invention

[0006] In order to avoid the situation where, after the furnace tube has been cleaned a certain number of times, some areas on the insulation barrel are over-etched, becoming a potential source of particle contamination, and when the wafer undergoes a subsequent thin film deposition process, the particle contamination source falls on the wafer surface and affects the processing quality of the wafer, the present invention proposes a furnace tube with a cleaning function and a furnace tube cleaning process.

[0007] In a first aspect, the present invention provides a cleaning process for a furnace tube, wherein the furnace tube includes a furnace body, and a side wall of the furnace body is provided with a temperature control area, including:

[0008] Lift the crystal boat and the insulation barrel into the furnace, seal the furnace and evacuate it;

[0009] Cleaning gas is introduced into the furnace body to clean the layer to be cleaned in the furnace body. During the cleaning process, the heating temperature of the first temperature control area in the temperature control area is gradually reduced, so that the final target temperature of the first temperature control area at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning, wherein the first temperature control area corresponds to the upper area of ​​the insulation barrel.

[0010] According to a specific implementation method of an embodiment of the present application, before the cleaning gas is introduced into the furnace body, it also includes: controlling the temperature of the temperature control area to an initial target temperature; wherein the initial target temperature of the first temperature control area is 5 to 10°C higher than the initial target temperature of the second temperature control area, wherein the second temperature control area corresponds to other areas in the temperature control area except the first temperature control area.

[0011] According to a specific implementation method of an embodiment of the present application, while controlling the temperature of the temperature control area to the initial target temperature, it also includes: introducing inert gas or nitrogen into the furnace body to a pressure inside the furnace body of 100mtorr to 1000mtorr.

[0012] According to a specific implementation of the embodiment of the present application, the method further includes:

[0013] During the cleaning process, the pressure inside the furnace body is maintained at 100mtorr to 1000mtorr.

[0014] According to a specific implementation of the embodiment of the present application, the cooling rate of the first temperature control area is: 0.1~1°C / min.

[0015] According to a specific implementation of the embodiment of the present application, the method further includes:

[0016] After the layer to be cleaned in the furnace body is cleaned, cleaning gas is continuously introduced into the furnace body for a period of time to ensure that the layer to be cleaned is completely cleaned.

[0017] According to a specific implementation of the embodiment of the present application, the method further includes:

[0018] After the layer to be cleaned in the furnace body is cleaned, an inert gas or nitrogen is continuously introduced into the furnace body for a period of time to remove by-products in the furnace body.

[0019] In a second aspect, the present invention provides a furnace tube with a cleaning function, the furnace tube comprising a furnace body, the side wall of the furnace body being provided with a temperature control area, including:

[0020] A temperature control module for heating the closed furnace tube and furnace body, the temperature control module including a first temperature control module, the temperature control area corresponding to the first temperature control module is a first temperature control area, and the first temperature control area corresponds to the upper area of ​​the insulation barrel;

[0021] The control module is configured to: control the cleaning gas to be introduced into the furnace body to clean the layer to be cleaned in the furnace body; during the cleaning process, control the heating temperature of the first temperature control area to gradually decrease, so that the final target temperature of the first temperature control area at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning.

[0022] According to a specific implementation of the embodiment of the present application, the temperature control module further includes a second temperature control module, and the temperature control area corresponding to the second temperature control module is a second temperature control area, and the second temperature control area corresponds to other areas of the temperature control area except the first temperature control area;

[0023] Before the cleaning gas is introduced into the furnace body, the control module is also configured to: control the temperature control module to control the temperature of the temperature control area to an initial target temperature; wherein, the initial target temperature of the first temperature control area corresponding to the first temperature control area is 5 to 10°C higher than the initial target temperature of the second temperature control area corresponding to the second temperature control module.

[0024] According to a specific implementation of the embodiment of the present application, the method further includes:

[0025] A pressure control module for adjusting the pressure conditions inside the furnace;

[0026] The control module is also configured to: control the temperature control module to control the temperature of the temperature control area to the initial target temperature, while controlling the pressure control module to adjust the pressure inside the furnace body to 100mtorr~1000mtorr, and during the cleaning process, control the pressure control module to adjust the pressure inside the furnace body to 100mtorr~1000mtorr.

[0027] The furnace tube with a cleaning function and the furnace tube cleaning process of the present invention gradually reduce the heating temperature of the first temperature control area corresponding to the upper area of ​​the insulation barrel; when the cleaning process is completed, the target temperature of the temperature control area corresponding to the upper area of ​​the insulation barrel is 5 to 10°C lower than the initial target temperature of the temperature control area, thereby protecting the insulation barrel, preventing over-etching during cleaning and generating a particle pollution source, ensuring the quality of wafer processing, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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 any creative work.

[0029] Figure 1 Shows a schematic structural diagram of a furnace tube;

[0030] Figure 2 shows a schematic cross-sectional structure diagram of a furnace tube; and

[0031] Figure 3 Shows a schematic diagram of the three-dimensional structure of the heat preservation barrel;

[0032] Figure 4 A schematic diagram of a furnace tube cleaning process according to an embodiment of the present invention is shown;

[0033] Figure 5 A schematic structural diagram of a furnace tube with a cleaning function according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 making creative efforts shall fall within the scope of protection of the present invention.

[0035] Figure 1 、 Figure 2In the furnace tube shown in the figure, in actual design, due to the large actual structural size of the furnace tube, the temperature control area 200 is prone to uneven heating in the process of heating the furnace body 100, where the temperature in some areas is too high and the temperature in some areas is too low. However, when the wafer undergoes a thin film deposition process, high requirements are placed on temperature accuracy and uniformity. During the production process, in order to make the temperature of each area of ​​the furnace body 100 uniform, and thus more accurately control the overall temperature of the furnace body 100, the temperature control area 200 is generally divided into multiple heating units, and then the temperature is controlled in different areas. For example, in this embodiment, the temperature control area 200 is divided into five heating units, namely the first heating unit 201, the second heating unit 202, the third heating unit 203, the fourth heating unit 204 and the fifth heating unit 205. During the process, the furnace body 100 is heated to the same target temperature by controlling multiple heating units at the same time, thereby controlling the temperature inside the furnace tube and furnace body 100 to achieve better uniformity. Specifically, each heating unit includes a heater (not shown), a temperature sensor (not shown) and a controller (not shown). During the heating process, the controller controls the heater to heat the sealed space inside the furnace body 100. At the same time, the temperature sensor monitors the temperature inside the furnace body 100 and transmits the monitored temperature data information to the controller in real time. Once it is detected that the temperature inside the furnace body 100 reaches the preset target temperature, the controller immediately controls the heater to stop heating.

[0036] After the thin film deposition process on the wafer is completed, the entire interior of the furnace body 100 needs to be etched and cleaned to remove the thin film deposition reactants produced by the previous thin film deposition process and ensure a clean environment for the next thin film deposition process. Considering the need to match the structural characteristics of existing furnace tubes, the general method adopted is: by controlling the various heating units in the temperature control area 200 to uniformly heat the furnace body 100 at the same temperature, and then allowing the cleaning gas to enter the inner tube 400 from the air inlet 301 provided on the fixing member 300, be transported upward within the inner tube 400, and then be discharged from the exhaust port 302 provided on the fixing member 300 through the gap between the inner tube 400 and the outer tube 500. However, the inventors of the present application have discovered that after the furnace body is cleaned a certain number of times, the yield rate of wafer processing will decrease. After analysis, the inventors of this application discovered that after the furnace body 100 has been cleaned a certain number of times, the surface of the fins in the upper area 701 of the insulation barrel corresponding to the fifth heating unit 205 of the insulation barrel 700 will become rough, and the degree of roughness of different areas of the same fin is different. The edge of the fin is subjected to high temperature for a longer time than the center, and the degree of etching is more serious than the center. Due to over-etching, a rough surface is formed. The more severe the roughness, the more likely it is to become a potential particle source. When the subsequent wafer undergoes a thin film deposition process, the rough insulation barrel fin surface forms a particle contamination source. When the reaction gas in the diffusion process is transported upward from the bottom of the inner tube 400, it is easy to carry the particle contamination source upward and then fall on the wafer surface, resulting in a decrease in the yield rate of wafer processing during the thin film deposition process. In order to solve this problem, the inventors of this case conducted research on this and proposed a furnace tube with a cleaning function and a furnace tube cleaning method to solve the problem of roughening the fin surface in the area of ​​the insulation barrel that is often subjected to high temperature reactions, extend the service life of the furnace tube, and ensure the quality of wafer processing. It is worth noting that the upper area 701 of the heat preservation barrel in this article specifically refers to the area inside the furnace body 100 and corresponding to the temperature control area when the heat preservation barrel lifts the wafer boat into the furnace body 100. Please refer to the Figure 2 and Figure 3 The upper area 701 of the heat preservation barrel is characterized by a fin having a relatively small diameter and several fins below the fin having a relatively small diameter.

[0037] Please refer to Figure 4 , Figure 4 FIG1 shows a flow chart of the cleaning process of the furnace tube according to an embodiment of the present invention. Figure 4 As shown, the cleaning process of the furnace tube of the present invention includes the following steps:

[0038] Step S100: Lift the wafer boat and the heat preservation barrel into the furnace body, seal the furnace body with the layer to be cleaned inside, and evacuate the furnace body.

[0039] Specifically, when closed, such as Figure 2As shown, the wafer boat 600 and the heat preservation barrel 700 rise to the inside of the inner tube 400, and the sealing cover 800 forms a seal with the bottom of the fixing member 300, making the interior of the furnace body a closed environment, and the internal space of the furnace body is evacuated to ensure the vacuum degree inside the furnace body.

[0040] Step S300: Cleaning gas is introduced into the furnace body to clean the layer to be cleaned in the furnace body. During the cleaning process, the heating temperature of the first temperature control area in the temperature control area is gradually reduced, so that the final target temperature of the first temperature control area at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning, wherein the first temperature control area corresponds to the upper area of ​​the insulation barrel.

[0041] Specifically, when the cleaning gas enters the furnace body for cleaning, since the heating unit is always in a heating state, the heating temperature of the upper part area 701 of the insulation barrel is always higher than that of the lower part area 702 of the insulation barrel. When the cleaning time is extended to ensure that the insulation barrel 700 is completely cleaned, the upper part area 701 of the insulation barrel is prone to over-etching. At the same time, because the heating unit is heated around the outside of the furnace body, the edge temperature of the fins in the upper part area 701 of the insulation barrel is higher than the center temperature of the fins, so that the cleaning etching reaction is slower in the center of the fin and faster at the edge. The result is that the cleaning rates of different areas of the same fin are inconsistent. When the edge of the fin has been cleaned, the center area of ​​the fin has not been completely cleaned. When the cleaning process is completed, the edge area of ​​the insulation barrel fin is much rougher than the center area of ​​the insulation barrel fin. The rougher area becomes a potential source of particles, affecting the processing quality of the wafer. In order to prevent the generation of particle sources, over-etching needs to be avoided. Therefore, during cleaning, the upper area of ​​the insulation barrel, especially the edge area of ​​the upper part of the insulation barrel, must not have a local over-temperature phenomenon. To this end, the present invention groups the temperature control area 200 during the cleaning process. Exemplarily, in this embodiment, the temperature control area 200 is divided into two temperature control areas. The first temperature control area is the fifth heating unit 205 corresponding to the upper area 701 of the insulation barrel, which is located at the lower part of the furnace tube; the second temperature control area is the other temperature control areas other than the first temperature control area. In this embodiment, the second temperature control area includes the first heating unit 201, the second heating unit 202, the third heating unit 203, and the fourth heating unit 204. During the cleaning process, the heating temperature of the first temperature control area, that is, the fifth heating unit 205 in the embodiment of the present invention, is gradually reduced. At the end of cleaning, the final target temperature of the first temperature control area corresponding to the upper area 701 of the insulation barrel is 5 to 10°C lower than the initial target temperature of the first temperature control area. Furthermore, the cooling rate of the fifth heating unit 205 in the first temperature-controlled area corresponding to the heat preservation barrel is controlled at 0.1 to 1°C / min. By controlling the temperature of the first temperature-controlled area to gradually decrease by 5 to 10°C from the initial target temperature during the cleaning process, the cleaning efficiency of the entire furnace body is made consistent, thereby ensuring that the cleaning process begins as soon as the cleaning gas enters the furnace body, thereby improving the cleaning efficiency; and preventing the upper area of ​​the heat preservation barrel from continuously being subjected to relatively strong cleaning etching, thereby preventing the occurrence of over-etching problems; at the same time, the gradual decrease in the temperature of the first temperature-controlled area corresponding to the upper area of ​​the heat preservation barrel avoids the problem of uneven heating of the center and edge of the fins themselves in the upper area of ​​the heat preservation barrel; and in many ways, avoiding the occurrence of the phenomenon that the surface of the heat preservation barrel fins becomes rough and thus becomes a potential source of particle contamination, thereby protecting the various components of the furnace tube, extending the service life of the furnace tube, ensuring the quality of wafer processing, and reducing production costs.

[0042] Preferably, before step S300, the cleaning process also includes: step S200: controlling the temperature of the temperature-controlled area to an initial target temperature; wherein the initial target temperature of the first temperature-controlled area is 5 to 10°C higher than the initial target temperature of the second temperature-controlled area, wherein the second temperature-controlled area corresponds to other areas in the temperature-controlled area except the first temperature-controlled area.

[0043] Specifically, when the purge gas enters the bottom of the inner tube 400, its temperature is relatively low and has not yet reached the reaction temperature. Therefore, the purge gas does not immediately begin to purge the inner tube 400. The purge gas is continuously heated as it flows upward, which produces a partial thermal decomposition reaction. This exothermic reaction causes the temperature of the gas at the top of the inner tube 400 to be significantly higher than that at the bottom of the inner tube 400. During the purge process, the purge gas first completely decomposes at the top of the inner tube 400 and the upper portion of the outer tube 500, producing sufficient substances capable of reacting with the layer to be cleaned within the furnace tube and body. These substances then gradually spread toward the bottom of the furnace body. This can easily lead to the top of the furnace body being cleaned first, with the bottom of the furnace body not starting until some time after the top has been cleaned. Consequently, the top of the furnace body is cleaned, but the bottom is not. Therefore, to ensure that the inner side of the bottom of the outer tube 500 and the lower portion 702 of the insulation barrel are fully cleaned, the cleaning time of the entire cleaning process must be extended. As a result, it is inevitable that the top of the furnace body will be damaged due to excessive cleaning.

[0044] During the actual cleaning process, different cleaning gases are selected based on the different layers to be cleaned, resulting from different thin film deposition processes. Based on the actual reaction temperature of the cleaning gas, the multiple heating units in temperature-controlled area 200 are grouped and controlled as described above, thereby selectively setting the heating temperature for each area of ​​furnace body 100. Before the cleaning gas is introduced into the furnace, the initial target temperature of the first temperature-controlled area is set 5-10°C higher than that of the second temperature-controlled area to accelerate the cleaning process at the bottom of the furnace body and improve cleaning efficiency.

[0045] Furthermore, while controlling the temperature of the temperature control area to the initial target temperature, an inert gas or nitrogen is introduced into the furnace body until the pressure inside the furnace body is 100mtorr to 1000mtorr, and then the introduction of the inert gas or nitrogen is stopped and the cleaning gas is introduced into the furnace body 100 to clean the layer to be cleaned in the furnace body 100. Similarly, during the cleaning process, the pressure inside the furnace body is maintained at

[0046] 100mtorr~1000mtorr.

[0047] Preferably, the cleaning process also includes step S400: after the layer to be cleaned in the furnace body is cleaned, cleaning gas is continuously introduced into the furnace body for a period of time to completely clean the layer to be cleaned. Exemplarily, the time for continuously introducing cleaning gas in the embodiment of the present invention is 3 to 5 minutes, and the flow rate can remain unchanged. It is worth noting that the time required for cleaning the layer to be cleaned in the furnace body can be judged by experience, and it can be directly judged as clean when the cleaning time is reached. The temperature change in the furnace body 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 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. 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 furnace body 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 furnace body 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.

[0048] Preferably, the cleaning process further includes step S500: After the layer to be cleaned within the furnace body is completely cleaned, an inert gas or nitrogen is continuously introduced into the furnace body for a period of time to remove byproducts within the furnace body, thereby completing the cleaning process. Exemplarily, in this embodiment of the present invention, nitrogen is selected. Furthermore, in this embodiment of the present invention, the flow rate of nitrogen introduced into the furnace body is 1.5 SL to 2 SL, and the continuous introduction time is 3 to 5 minutes.

[0049] The embodiment of the present invention also provides a furnace tube with a cleaning function. Figure 5 , Figure 5 FIG1 shows a schematic diagram of the furnace tube structure with a cleaning function according to an embodiment of the present invention. Figure 5 As shown, the furnace tube 501 with cleaning function includes:

[0050] A temperature control module 5012 is used to heat the closed furnace tube body 5011.

[0051] Control module 5014 is configured to control the flow of cleaning gas into furnace body 5011 to clean the layer to be cleaned within furnace body 5011. During the cleaning process, the heating temperature of the first temperature control module in the temperature control area is gradually reduced so that the final target temperature of the first temperature control module at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning. The temperature control area of ​​the first temperature control module corresponds to the upper portion 701 of the heat preservation barrel. Furthermore, when the cleaning gas is introduced into furnace body 5011, the cleaning gas is controlled to enter furnace body 5011 from the bottom of furnace body 5011 to clean the layer to be cleaned within furnace body 5011.

[0052] Furthermore, the number of temperature control modules 5012 is at least two, and each temperature control module 5012 includes at least one heating unit 50121; before the cleaning gas is introduced into the furnace body, the control module 5014 is also configured to: control the temperature control module 5012 to control the temperature of the temperature control area to the initial target temperature; wherein, the initial target temperature of the first temperature control module is 5 to 10°C higher than the initial target temperature of the second temperature control module, wherein the second temperature control module corresponds to other areas of the temperature control module except the temperature control area corresponding to the first temperature control module.

[0053] Preferably, the furnace tube 501 further includes: a pressure control module 5013 for adjusting the pressure inside the furnace body.

[0054] Furthermore, the control module 5014 is also configured to: control the temperature increase of the temperature control area while controlling the pressure control module 5013 to adjust the pressure inside the furnace body to 100mtorr~1000mtorr, and during the cleaning process, control the pressure control module 5013 to adjust the pressure inside the furnace body to 100mtorr~1000mtorr.

[0055] It should be understood that furnace tubes with cleaning functions and furnace tube cleaning processes are not only applicable to cleaning furnace tubes after thin film deposition processes, but also to cleaning furnace tubes after thermal diffusion processes. Next, the present invention further illustrates the furnace tube cleaning process according to an embodiment of the present invention, using a silicon nitride thin film as the layer to be cleaned, as a product of the thin film deposition process, and using a non-metallic fluoride gas, exemplarily chlorine trifluoride gas, as the cleaning gas to clean the furnace tube body.

[0056] Please refer to Figure 1, an embodiment of the present invention provides a furnace body with a silicon nitride film inside, the entire furnace body is sealed, the furnace body is evacuated, and the vacuum degree inside the furnace body is ensured. In this embodiment, the temperature control area 200 is divided into five heating units, namely the first heating unit 201, the second heating unit 202, the third heating unit 203, the fourth heating unit 204 and the fifth heating unit 205. The above five heating units are divided into two temperature control areas. The first temperature control area is the fifth heating unit 205 corresponding to the area 701 of the insulation barrel 700 at the lower part of the furnace tube; the second temperature control area is the other temperature control areas except the first temperature control area. In this embodiment, the second temperature control area includes the first heating unit 201, the second heating unit 202, the third heating unit 203, and the fourth heating unit 204. After the five heating units are divided, each temperature control area can be precisely heated and temperature controlled, thereby realizing different temperature control of different areas in the furnace body.

[0057] The heating temperatures of each temperature-controlled zone are selected and set based on the temperature conditions required for the reaction between the silicon nitride film and the cleaning gas. Before the cleaning gas is introduced into the furnace, the target temperature of the first temperature-controlled zone is set to 305-310°C, i.e., the heating temperature of the fifth heating unit 205 is set to 305-310°C. The target temperature of the second temperature-controlled zone is set to 300°C, i.e., the heating temperature of the first heating unit 201, the second heating unit 202, the third heating unit 203, and the fourth heating unit 204 are all the same, i.e., 300°C.

[0058] While controlling the internal temperature of the furnace body 100 to rise, an inert gas or nitrogen is introduced into the furnace body until the pressure inside the furnace body 100 reaches 100mtorr to 1000mtorr. Then, a cleaning gas is introduced into the furnace body 100 to clean the layer to be cleaned in the furnace body 100. During the cleaning process, the heating temperature of the fifth heating unit 205 corresponding to the region 701 of the heat-insulating barrel 700 is gradually reduced. Furthermore, the cooling rate of the heating temperature of the first temperature-controlled region corresponding to the region 701 of the heat-insulating barrel 700 is controlled to be 0.1 to 1°C / min. Until the cleaning is completed, the final target temperature of the first temperature-controlled region is 5 to 10°C lower than the initial target temperature of the first temperature-controlled region. In this embodiment, after the cleaning is completed, the final target temperature of the first temperature-controlled region reaches 290 to 295°C, and the temperature of the second temperature-controlled region remains at 300°C. Similarly, during the cleaning process, the internal pressure of the furnace body is maintained at 100mtorr to 1000mtorr.

[0059] In order to ensure sufficient reaction, the silicon nitride layer inside the furnace tube is cleaned. After it is judged to be clean, chlorine trifluoride gas is continuously injected at a flow rate of 1.5SL~2SL for 3~5 minutes to further ensure that the silicon nitride film layer is completely cleaned and the cleaning effect is ensured. Then, nitrogen gas is injected at a flow rate of 1.5SL~2SL for 3~5 minutes to remove the by-products.

[0060] The present invention implements zoned temperature control on the furnace tube to achieve precise control of different temperatures in different zones, so as to make the cleaning efficiency of the entire furnace body tend to be consistent. At the same time, the temperature of the local temperature control zone is dynamically adjusted in a targeted manner to protect the various components of the furnace tube and avoid the generation of potential particle sources. This improves the cleaning efficiency of the furnace tube and the furnace body while protecting the various components of the furnace tube, extending the service life of the furnace tube, ensuring the quality of wafer processing, and reducing production costs.

[0061] 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 replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A furnace tube cleaning process, wherein the furnace tube comprises a furnace body, and the side wall of the furnace body is provided with a temperature control area, characterized in that: include: Lift the crystal boat and the insulation barrel into the furnace, seal the furnace and evacuate it; Cleaning gas is introduced into the furnace body to clean the layer to be cleaned in the furnace body. During the cleaning process, the heating temperature of the first temperature control area in the temperature control area is gradually reduced, so that the final target temperature of the first temperature control area at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning, wherein the first temperature control area corresponds to the upper area of ​​the insulation barrel.

2. The cleaning process according to claim 1, characterized in that Before introducing the cleaning gas into the furnace body, it also includes: controlling the temperature of the temperature control area to an initial target temperature; wherein the initial target temperature of the first temperature control area is 5 to 10°C higher than the initial target temperature of the second temperature control area, wherein the second temperature control area corresponds to other areas in the temperature control area except the first temperature control area.

3. The cleaning process according to claim 2, characterized in that While controlling the temperature of the temperature-controlled area to the initial target temperature, the process also includes: introducing inert gas or nitrogen into the furnace body until the pressure inside the furnace body is 100 mtorr to 1000 mtorr.

4. The cleaning process according to claim 1, characterized in that Also includes: During the cleaning process, the pressure inside the furnace body is maintained at 100mtorr to 1000mtorr.

5. The cleaning process according to claim 1, characterized in that The cooling rate of the first temperature control area is 0.1-1°C / min.

6. The cleaning process according to claim 1, characterized in that Also includes: After the layer to be cleaned in the furnace body is cleaned, cleaning gas is continuously introduced into the furnace body for a period of time to ensure that the layer to be cleaned is completely cleaned.

7. The cleaning process according to claim 1, characterized in that Also includes: After the layer to be cleaned in the furnace body is cleaned, an inert gas or nitrogen is continuously introduced into the furnace body for a period of time to remove by-products in the furnace body.

8. A furnace tube with a cleaning function, comprising a furnace body, a side wall of which is provided with a temperature control area, characterized in that: include: A temperature control module for heating the closed furnace tube and furnace body, the temperature control module including a first temperature control module, the temperature control area corresponding to the first temperature control module is a first temperature control area, and the first temperature control area corresponds to the upper area of ​​the insulation barrel; A control module is configured to: control the cleaning gas to pass into the furnace body to clean the layer to be cleaned in the furnace body; during the cleaning process, control the heating temperature of the first temperature control module to gradually decrease, so that the final target temperature of the first temperature control module at the end of cleaning is 5 to 10°C lower than the initial target temperature at the beginning of cleaning.

9. The furnace tube according to claim 8, characterized in that The temperature control module further includes a second temperature control module, the temperature control area corresponding to the second temperature control module is a second temperature control area, and the second temperature control area corresponds to other areas of the temperature control area except the first temperature control area; Before the cleaning gas is introduced into the furnace body, the control module is also configured to: control the temperature control module to control the temperature of the temperature control area to an initial target temperature; wherein, the initial target temperature of the first temperature control area corresponding to the first temperature control module is 5 to 10°C higher than the initial target temperature of the second temperature control area corresponding to the second temperature control module.

10. The furnace tube according to claim 8, characterized in that Also includes: A pressure control module for adjusting the pressure conditions inside the furnace; The control module is also configured to: control the temperature control module to control the temperature of the temperature control area to the initial target temperature, while controlling the pressure control module to adjust the pressure inside the furnace body to 100mtorr~1000mtorr, and during the cleaning process, control the pressure control module to adjust the pressure inside the furnace body to 100mtorr~1000mtorr.

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