Method for preparing thin film for atmospheric pressure furnace tube system and atmospheric pressure furnace tube system

Abstract

The present application discloses a method for preparing a thin film in an atmospheric pressure furnace tube system and an atmospheric pressure furnace tube system, the method comprising: obtaining an operating air pressure inside the atmospheric pressure furnace tube as a first air pressure; obtaining an air pressure at a tail pipe of the atmospheric pressure furnace tube as a second air pressure; adjusting the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference to maintain the first air pressure constant; and preparing a thin film in the atmospheric pressure furnace tube based on the first air pressure and a preset time. The embodiments of the present application can maintain the operating air pressure inside the atmospheric pressure furnace tube constant by adjusting the pressure difference between the first air pressure and the second air pressure, thereby maintaining a stable rate for preparing the thin film and improving the consistency of the thickness of the prepared film.

Description

Technical Field

[0001] The present application generally relates to the field of semiconductor technology and more specifically to a method for preparing a thin film for an atmospheric pressure furnace tube system and an atmospheric pressure furnace tube system. Background Art

[0002] Silicon dioxide thin films play a crucial role in semiconductor devices. Thermal oxidation is a key method for producing silicon dioxide. This method involves chemically reacting a silicon wafer with an oxidizing gas (such as oxygen and water vapor) at high temperature to form a dense silicon dioxide film on the surface of the wafer. This resulting silicon dioxide exhibits excellent electrical insulation and process feasibility. Thermal oxidation is widely used in the microelectronics industry for gate dielectrics, protective and isolation layers, surface passivation treatments, or masking layers.

[0003] When using thermal oxidation to prepare silicon dioxide film, a normal pressure furnace tube can be used. Furthermore, when preparing a film in a normal pressure furnace tube, the thickness of the film can be affected by pressure, the concentration of the oxidizing gas, temperature and reaction time. Specifically, the greater the pressure, the faster the rate of preparing the silicon dioxide film, and when other factors remain the same, the thickness of the silicon dioxide film is greater. However, in the related art, a pressure pump is not used in a normal pressure furnace tube to control the reaction pressure in the normal pressure furnace tube, which makes the thickness of the film affected by atmospheric pressure when preparing the film in the normal pressure furnace tube. As the chip size decreases and the line width becomes smaller, the requirements for process accuracy are getting higher and higher. The change in the thickness of the film with the change in atmospheric pressure will make the stability of the film thickness of the manufactured chip poor and the yield rate reduced.

[0004] In view of this, there is an urgent need to provide a method for preparing a thin film using an atmospheric pressure furnace tube system and a solution for the atmospheric pressure furnace tube system, so as to improve the consistency of the thickness of the prepared thin film. Summary of the Invention

[0005] In order to at least solve one or more of the technical problems mentioned above, the present application proposes a method for preparing a thin film for an atmospheric pressure furnace tube system and an atmospheric pressure furnace tube system in multiple aspects.

[0006] In a first aspect, the present application provides a method for preparing a thin film for a normal pressure furnace tube system, the method comprising: obtaining a working gas pressure inside the normal pressure furnace tube as a first gas pressure; obtaining the gas pressure of the tail pipe of the normal pressure furnace tube as a second gas pressure; based on the first gas pressure and the second gas pressure, adjusting the pressure difference between the first gas pressure and the second gas pressure so that the pressure difference between the first gas pressure and the second gas pressure is equal to a first preset pressure difference to maintain the first gas pressure unchanged; based on the first gas pressure and a preset time, preparing a thin film in the normal pressure furnace tube.

[0007] In some embodiments, the method further includes: before adjusting the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference, the method further includes: obtaining the lowest atmospheric pressure within a preset period as a reference pressure; obtaining the current value of the atmospheric pressure as the current pressure; and calculating the first preset pressure difference of the atmospheric furnace tube based on the reference pressure and the current pressure.

[0008] In some embodiments, the atmospheric pressure furnace tube system includes an exhaust pump, the input end of the exhaust pump is connected to the tail pipe of the atmospheric pressure furnace tube, and the output end of the exhaust pump is connected to the atmosphere. The calculation of the first preset pressure difference of the atmospheric pressure furnace tube based on the reference air pressure and the current air pressure includes: setting the pressure difference between the output end and the input end of the exhaust pump to a second preset pressure difference; obtaining the atmospheric pressure coefficient of the atmospheric pressure furnace tube as the first coefficient; and calculating the first preset pressure difference of the atmospheric pressure furnace tube based on the reference air pressure, the current air pressure, the second preset pressure difference and the first coefficient.

[0009] In some embodiments, the preparing a thin film in the atmospheric pressure furnace tube based on the first gas pressure and the preset time includes: obtaining historical data of the atmospheric pressure furnace tube, wherein the historical data includes first data on the relationship between film forming pressure, film forming time and film forming thickness; obtaining a preset time based on the first data, the first gas pressure and the preset film forming thickness; and preparing a thin film in the atmospheric pressure furnace tube based on the first gas pressure and the preset time.

[0010] In some embodiments, the atmospheric pressure furnace tube system includes an exhaust device located between the atmospheric pressure furnace tube and the tail pipe, and adjusting the pressure difference between the first air pressure and the second air pressure includes: adjusting the speed of gas circulation in the exhaust device to adjust the pressure difference between the first air pressure and the second air pressure.

[0011] In some embodiments, the atmospheric pressure furnace tube includes a horizontal atmospheric pressure furnace tube or a vertical atmospheric pressure furnace tube.

[0012] In some embodiments, a wafer boat is disposed in the atmospheric pressure furnace tube, and the wafer boat is used to store wafers so as to form a thin film on the surface of the wafer.

[0013] In some embodiments, the thin film includes at least one of a gate oxide layer, a diffusion layer, and an epitaxial layer.

[0014] In a second aspect, the present application provides a normal pressure furnace tube system, the system comprising: a first measuring module for obtaining the working air pressure inside the normal pressure furnace tube as the first air pressure; a second measuring module for obtaining the air pressure of the tail pipe of the normal pressure furnace tube as the second air pressure; an adjustment module for adjusting the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure, so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference to maintain the first air pressure unchanged; and a preparation module for preparing a thin film in the normal pressure furnace tube based on the first air pressure and a preset time.

[0015] The unexpected technical effect of the present invention is: through the method for preparing a thin film for a normal pressure furnace tube system and the normal pressure furnace tube system provided above, the embodiment of the present application can maintain the working gas pressure inside the normal pressure furnace tube unchanged by adjusting the second gas pressure of the tail pipe of the normal pressure furnace tube, thereby maintaining a stable rate of preparing the thin film, accurately controlling the thickness of the silicon dioxide film, and making the thickness of the prepared film have good consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the exemplary embodiments of the present application will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0017] Figure 1a An exemplary flow chart of a method 100 for preparing a thin film in an atmospheric pressure furnace tube system according to some embodiments of the present application is shown;

[0018] Figure 1b A diagram showing the relationship between pressure and film thickness according to some embodiments of the present application is shown;

[0019] Figure 2a An exemplary flow chart showing a method 200 for preparing a thin film in an atmospheric furnace tube system according to other embodiments of the present application is shown;

[0020] Figure 2b An exemplary coordinate diagram showing changes in atmospheric pressure within a preset period according to other embodiments of the present application is shown;

[0021] Figure 3 An exemplary block diagram of a method 300 for calculating a first preset pressure difference according to some embodiments of the present application is shown;

[0022] Figure 4 An exemplary block diagram of a method 400 for preparing a thin film in an atmospheric pressure furnace tube based on a first gas pressure and a preset time according to some embodiments of the present application is shown;

[0023] Figure 5 An exemplary block diagram of an atmospheric pressure furnace tube system according to some embodiments of the present application is shown. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0025] It should be understood that the terms "include" and "comprising" used in the description and claims of this application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this specification and claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" as used in this specification and claims refers to any and all possible combinations of one or more of the associated listed items, including and including these combinations.

[0027] As used in this specification and claims, the term “if” can be interpreted as “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [described condition or event] is detected” can be interpreted as meaning “upon determination” or “in response to determining” or “upon detection of [described condition or event]” or “in response to detecting [described condition or event],” depending on the context.

[0028] The specific implementation of the present application will be described in detail below with reference to the accompanying drawings.

[0029] Figure 1a An exemplary flow chart of a method 100 for preparing a thin film in an atmospheric furnace tube system according to some embodiments of the present application is shown. Figure 1b FIG1 shows the relationship between pressure and film thickness of some embodiments of the present application. Figure 1a and Figure 1bAs shown, the method includes: step S101 obtaining the working air pressure inside the atmospheric pressure furnace tube as the first air pressure; step S102 obtaining the air pressure of the tail pipe of the atmospheric pressure furnace tube as the second air pressure; step S103 adjusting the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure, so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference to maintain the first air pressure unchanged; step S104 preparing a thin film in the atmospheric pressure furnace tube based on the first air pressure and the preset time.

[0030] In some embodiments, a normal-pressure furnace is a tubular heating furnace operating at normal pressure (e.g., atmospheric pressure). By precisely controlling the temperature and gas environment, it can be used for thermal oxidation processes to grow thin films on wafer surfaces. The normal-pressure furnace can be provided with an inlet and an exhaust port, through which reactant gases enter the normal-pressure furnace. The reactant gases can be selected based on the reaction type. For example, when growing a silicon dioxide film on a wafer surface, the reactant gases can include oxygen and / or water vapor.

[0031] In some embodiments, a wafer boat is disposed in the atmospheric pressure furnace tube, and the wafer boat is used to store wafers so as to form a thin film on the surface of the wafer.

[0032] The main body of the atmospheric furnace tube can be a high-purity quartz glass tube, which can be equipped with a quartz boat inside. This boat can be made of high-purity quartz or silicon carbide-coated quartz, which is resistant to high temperatures and avoids metal contamination. Furthermore, the quartz boat can be configured as a multi-layered trough structure, with wafers placed in each layer of troughs. The quartz boat can then be used to transport the wafers into the atmospheric furnace for thermal oxidation.

[0033] In some embodiments, the working pressure inside the atmospheric pressure furnace tube can be the pressure in the area where the wafer is located inside the atmospheric pressure furnace tube. When the wafer is placed on a quartz boat, the working pressure can be the pressure in the area where the quartz boat is located. It should be understood that the actual value of the working pressure can fluctuate slightly based on the atmospheric pressure. For example, the working pressure can be slightly greater than the atmospheric pressure, slightly less than the atmospheric pressure, or equal to the atmospheric pressure, and the working pressure of the atmospheric pressure furnace tube can be affected by changes in the atmospheric pressure. For example, when the atmospheric pressure increases, the working pressure of the atmospheric pressure furnace tube can increase, and when the atmospheric pressure decreases, the working pressure of the atmospheric pressure furnace tube can decrease.

[0034] Further, if Figure 1b As shown, the horizontal axis in the figure can be time, the atmospheric pressure curve in the figure can represent the change of atmospheric pressure with time, and the film thickness curve in the figure can represent the change of film thickness with time. It can be understood that when Figure 1bWhen the atmospheric pressure decreases, the thickness of the film may also tend to decrease. Figure 1b When the atmospheric pressure increases, the thickness of the film also tends to increase.

[0035] Therefore, when the working pressure of the atmospheric furnace tube changes with the atmospheric pressure, the thickness of the film grown on the wafer arranged in the atmospheric furnace tube may also change, resulting in a lack of consistency in the thickness of the film finally prepared.

[0036] In some embodiments, the operating gas pressure can be obtained by providing a pressure measuring element or a flow measuring element. Specifically, the pressure measuring element can include a pressure sensor, which can be provided at a location such as the inlet or exhaust end of the atmospheric pressure furnace tube to obtain the operating gas pressure. Furthermore, the operating gas pressure within the atmospheric pressure furnace tube can be obtained by determining the flow rate of the gas within the atmospheric pressure furnace tube based on the gas state equation, thereby obtaining the first gas pressure.

[0037] In some embodiments, the exhaust end of the atmospheric furnace tube can be connected to one end of the regulating valve, and the other end of the regulating valve can be connected to the tail pipe. In some embodiments, the air pressure in the tail pipe can be measured by a pressure measuring element to obtain the second air pressure.

[0038] In some embodiments, the first gas pressure may be greater than the second gas pressure, and the second gas pressure may be greater than atmospheric pressure.

[0039] When the pressure difference between the first and second pressures needs to be adjusted, the pressure difference between the first and second pressures can be changed by adjusting the regulating valve. Specifically, one end of the regulating valve can be connected to the exhaust end of the atmospheric pressure furnace tube, and the other end of the regulating valve can be connected to the tail pipe. Gas within the atmospheric pressure furnace tube can flow from the exhaust end of the atmospheric pressure furnace tube through the regulating valve into the tail pipe. Furthermore, the valve core of the regulating valve can change the flow area between the valve core and the valve seat by moving or rotating, thereby changing the flow rate of gas through the regulating valve to achieve pressure regulation. It is understood that when the flow area between the valve core and the valve seat decreases, the flow rate of gas through the regulating valve decreases, which can increase the pressure inside the atmospheric pressure furnace tube, thereby changing the pressure difference between the first and second pressures, thereby increasing the pressure difference between the first and second pressures; when the flow area between the valve core and the valve seat increases, the flow rate of gas through the regulating valve increases, which can reduce the pressure inside the atmospheric pressure furnace tube, thereby changing the pressure difference between the first and second pressures, thereby decreasing the pressure difference between the first and second pressures.

[0040] It should be understood that when the aforementioned regulating valve is not present in the atmospheric pressure furnace tube system or the regulating valve is in a non-operating state, the pressure difference between the first and second air pressures can remain unchanged. Therefore, when the external air pressure increases, the first and second air pressures can increase simultaneously, while the pressure difference between the first and second air pressures can remain unchanged; when the external air pressure decreases, the first and second air pressures can decrease simultaneously, while the pressure difference between the first and second air pressures can also remain unchanged. When the external air pressure changes, the aforementioned regulating valve can be used to change the pressure difference between the first and second air pressures, thereby maintaining the first air pressure constant.

[0041] In some embodiments, the pressure difference between the first air pressure and the second air pressure is a first preset pressure difference. In some embodiments, the first air pressure and the second air pressure can be obtained by measuring them separately to obtain the pressure difference between the first air pressure and the second air pressure. In other embodiments, the pressure difference between the first air pressure and the second air pressure can also be obtained by providing a differential pressure gauge. Specifically, one end of the differential pressure gauge can be connected to the input end of the atmospheric pressure furnace tube or the regulating valve, and the other end of the differential pressure gauge can be connected to the tail pipe. The pressure difference between the working air pressure and the air pressure inside the tail pipe can be obtained by the differential pressure gauge, thereby obtaining the pressure difference between the first air pressure and the second air pressure.

[0042] In some embodiments, the first predetermined pressure difference can be determined by the ambient air pressure and the atmospheric pressure coefficient of the atmospheric furnace tube. The atmospheric pressure coefficient of the atmospheric furnace tube can be fixed. After measuring the ambient air pressure, the first predetermined pressure difference can be adjusted based on changes in the ambient air pressure. Furthermore, the pressure difference between the first and second air pressures can be adjusted based on changes in the first predetermined pressure difference so that the first air pressure remains constant. It is understood that in this case, the pressure difference between the first and second air pressures is variable.

[0043] After the pressure difference between the first air pressure and the second air pressure is adjusted so that the first air pressure remains unchanged, a thin film can be prepared on the wafer inside the atmospheric pressure furnace tube. It should be understood that when preparing a thin film in a normal pressure furnace tube, the thickness of the film can be related to the time of film growth and the size of the working pressure. Therefore, a relationship diagram between the time of film growth, the working pressure and the thickness of the film can be obtained based on historical data. Furthermore, when it is necessary to prepare a thin film, the preset thickness of the film can be determined according to demand, and then the preset time can be obtained based on the aforementioned relationship diagram, the working pressure and the preset thickness. Furthermore, a thin film can be prepared in a normal pressure furnace tube by using the preset time and working pressure, wherein the aforementioned working pressure can be the first air pressure.

[0044] In some embodiments, the thin film includes at least one of a gate oxide layer, a diffusion layer, and an epitaxial layer.

[0045] It is understood that different thin films can be generated in an atmospheric pressure furnace tube by setting different reaction gases and different reaction parameters. Specifically, a gate oxide layer can be obtained by passing a mixture of oxygen and water vapor into the atmospheric pressure furnace tube. Furthermore, impurities (such as phosphorus, boron, etc.) can be applied to the surface of the wafer, and then the wafer containing the aforementioned impurities is placed in the atmospheric pressure furnace tube, and a diffusion layer can be grown through the reaction. Furthermore, a wafer with silane on its surface can be placed in an atmospheric pressure furnace tube, and the silane can be decomposed and deposited on the surface of the wafer through high-temperature treatment to form an epitaxial layer.

[0046] In some embodiments, the atmospheric pressure furnace tube includes a horizontal atmospheric pressure furnace tube or a vertical atmospheric pressure furnace tube.

[0047] In some embodiments, the quartz tubes in a horizontal atmospheric furnace tube can be positioned horizontally, and the silicon wafers can be placed on a quartz wafer boat, which can be placed on a carrier made of silicon carbide with front and rear baffles. In other embodiments, the quartz tubes in a vertical atmospheric furnace tube can be positioned vertically, and the silicon wafers can be placed on a quartz tower. Preferably, a vertical atmospheric furnace tube is selected, as it occupies a small area and facilitates loading and unloading of silicon wafers.

[0048] With this setup, when thin films are produced within a normal-pressure furnace, if the external atmospheric pressure changes, the pressure difference between the first and second pressures can be adjusted to maintain the first pressure constant, thereby ensuring greater consistency in the thickness of the produced thin films. Furthermore, when producing small, low-linewidth chips, product accuracy can be improved. Furthermore, the number of products that do not meet requirements can be reduced, thereby improving the yield rate.

[0049] It is understood that the above description is exemplary rather than restrictive. For example, the content display method according to the present invention may not be limited to including only steps S101, S102, S103 and S104 shown in the figure, but may also include other steps. Figure 2a An exemplary description is given.

[0050] Figure 2a An exemplary flow chart of a method 200 for preparing a thin film in an atmospheric pressure furnace tube system according to some other embodiments of the present application is shown. Figure 2b The following description shows an exemplary coordinate diagram of atmospheric pressure changes in a preset period in some other embodiments of the present application. Figure 1a The method 100 for preparing a thin film is described as an embodiment of the present invention. Figure 1a The description of the content display method 100 can also be applied to the following Figure 2a 's description.

[0051] like Figure 2a As shown in , the method 200 for preparing a thin film may include: step S201 obtaining the lowest atmospheric pressure within a preset period as a reference pressure; step S202 obtaining the current value of the atmospheric pressure as the current pressure; step S203 calculating a first preset pressure difference of the atmospheric furnace tube based on the reference pressure and the current pressure; step S204 obtaining the working pressure inside the atmospheric furnace tube as the first pressure; step S205 obtaining the pressure of the tail pipe of the atmospheric furnace tube as the second pressure; step S206 adjusting the pressure difference between the first pressure and the second pressure based on the first pressure and the second pressure so that the pressure difference between the first pressure and the second pressure is equal to the first preset pressure difference to maintain the first pressure unchanged; step S207 preparing a thin film in the atmospheric furnace tube based on the first pressure and the preset time. Steps S204, S205, S206 and S207 can be combined with the above Figure 1a Step S101, step S102, step S103 and step S104 described are the same or similar and will not be repeated here.

[0052] exist Figure 2b As can be seen in the figure, the atmospheric pressure can vary within the preset period. In some embodiments, the preset period can be six months, one year, or determined based on demand. The atmospheric pressure within the preset period can be obtained from an official atmospheric pressure database (e.g., a meteorological information center database or a climate center database). Furthermore, the atmospheric pressure within the preset period can also be obtained through measurement. Specifically, a pressure measuring instrument can be used to measure the atmospheric pressure multiple times at set time intervals.

[0053] In some embodiments, when multiple atmospheric pressure values ​​are obtained within a preset period, the lowest atmospheric pressure among the multiple atmospheric pressure values ​​can be used as the reference atmospheric pressure. It is understood that the shorter the time interval, the more atmospheric pressure values ​​are measured, and the more consistent the obtained lowest atmospheric pressure is with the actual lowest atmospheric pressure value within the preset period.

[0054] In other embodiments, after obtaining multiple atmospheric pressure values ​​within a preset period, multiple scatter plots of atmospheric pressure changes over time can be obtained. Furthermore, by fitting the scattered points in the scatter plot, a continuous relationship graph of atmospheric pressure changes over time can be obtained. After obtaining the continuous relationship graph, the minimum atmospheric pressure value in the graph can be used as the reference atmospheric pressure.

[0055] In some embodiments, a pressure measuring device can be used to measure the current value of atmospheric pressure to obtain the current atmospheric pressure. It is understood that when using an atmospheric pressure furnace tube to prepare a thin film, the atmospheric pressure furnace tube can be located within a preparation site, which can include a factory, laboratory, or other required location. The aforementioned factory can include a semiconductor fabrication plant (FAB), etc.

[0056] In some embodiments, a pressure measuring device can be set on the above-mentioned preparation site so that the atmospheric pressure of the area where the preparation site is located can be obtained to obtain the current air pressure. It is understandable that the atmospheric pressure can vary in different areas. By using the atmospheric pressure of the area where the preparation site is located as the current air pressure, the current air pressure can be obtained more accurately. In some embodiments, the first preset pressure difference can be calculated by combining the reference air pressure and the current air pressure. Figure 3 The calculation formula of the first preset pressure difference is introduced.

[0057] It should be understood that the first preset pressure difference can be affected by both the baseline air pressure and the current air pressure. Within a preset period, the baseline air pressure can remain constant, while the first preset pressure difference can vary with changes in the current air pressure. When the current air pressure increases, the first preset pressure difference can decrease; and when the current air pressure decreases, the first preset pressure difference can increase.

[0058] In some embodiments, the pressure difference between the first and second air pressures in the atmospheric pressure furnace tube system can be adjusted by an exhaust device located between the atmospheric pressure furnace tube and the tail pipe. When the atmospheric pressure furnace tube system does not include an exhaust device, or when the exhaust device is not operating, the pressure difference between the first and second air pressures can remain unchanged. Specifically, when the current air pressure increases, the first and second air pressures can increase simultaneously, while the pressure difference between the first and second air pressures can remain unchanged; when the current air pressure decreases, the first and second air pressures can decrease simultaneously, while the pressure difference between the first and second air pressures can also remain unchanged.

[0059] In some embodiments, when the atmospheric pressure furnace tube system includes an exhaust device, the exhaust device can adjust the pressure difference between the first air pressure and the second air pressure. When the current air pressure changes, the second air pressure can also change. In this case, adjusting the pressure difference between the first and second air pressures can keep the first air pressure constant. Specifically, when the current air pressure increases, the second air pressure can also increase. In this case, the pressure difference between the first and second air pressures can be reduced, thereby keeping the first air pressure constant. When the current air pressure decreases, the second air pressure can also decrease. In this case, the pressure difference between the first and second air pressures can be increased, thereby keeping the first air pressure constant.

[0060] Therefore, by setting the pressure difference between the first air pressure and the second air pressure to be the first preset pressure difference, the first air pressure can be maintained unchanged. Specifically, when the current air pressure increases, the second air pressure can increase, and the first preset pressure difference can be reduced. By setting the pressure difference between the first air pressure and the second air pressure to be equal to the first preset pressure difference, the pressure difference between the first air pressure and the second air pressure can also be reduced. When the second air pressure increases, the first air pressure can be maintained unchanged. The specific relationship between the first air pressure, the second air pressure, the first preset pressure difference and the current air pressure will be discussed later in conjunction with Figure 3 Provide detailed explanation.

[0061] By fitting the scattered points, the lowest air pressure can be accurately obtained. Furthermore, by using the atmospheric pressure within the preparation site as the current air pressure, the influence of the atmospheric pressure in other areas can be reduced, thereby obtaining the current air pressure more accurately and avoiding interference from the atmospheric pressure in other areas.

[0062] In some embodiments, the pressure difference between the first air pressure and the second air pressure is equal to the first preset pressure difference.

[0063] In some embodiments, the first preset pressure difference can be obtained by the following formula:

[0064]

[0065] in, Can be the first gas pressure ， Can be the second air pressure, It can be a first preset pressure difference.

[0066] It is understood that when the current air pressure increases, the first preset pressure difference can be reduced while the second air pressure can be increased, thereby maintaining the first air pressure constant; when the current air pressure decreases, the first preset pressure difference can be increased while the second air pressure can be reduced, thereby maintaining the first air pressure constant. Therefore, by adjusting the pressure difference between the first and second air pressures so that the pressure difference between the first and second air pressures equals the first preset pressure difference, the first air pressure can be maintained constant.

[0067] Figure 3 FIG. 3 shows an exemplary block diagram of a method 300 for calculating a first preset pressure difference according to some embodiments of the present application. Figure 3As shown, the atmospheric pressure furnace tube system may include an exhaust pump, the input end of the exhaust pump is connected to the tail pipe of the atmospheric pressure furnace tube, and the output end of the exhaust pump is connected to the atmosphere, and the calculation of the first preset pressure difference of the atmospheric pressure furnace tube based on the reference air pressure and the current air pressure includes: step S301: setting the pressure difference between the output end and the input end of the exhaust pump to a second preset pressure difference; step S302: obtaining the atmospheric pressure coefficient of the atmospheric pressure furnace tube as the first coefficient; step S303: calculating the first preset pressure difference of the atmospheric pressure furnace tube based on the reference air pressure, the current air pressure, the second preset pressure difference and the first coefficient.

[0068] In some embodiments, the tail pipe of the atmospheric pressure furnace tube may include a tail pipe first end, a tail pipe second end, and a tail pipe middle end, wherein the tail pipe first end may include an end of the tail pipe facing the atmospheric pressure furnace tube, the tail pipe second end may include an end of the tail pipe away from the atmospheric pressure furnace tube, and the tail pipe middle end may be the portion between the tail pipe first end and the tail pipe second end.

[0069] In some embodiments, the first end of the tail pipe may be connected to the output end of the atmospheric pressure furnace tube, the middle end of the tail pipe may be provided with a regulating valve, and the second end of the tail pipe may be connected to the vacuum pump.

[0070] In some embodiments, the reaction gas in the atmospheric furnace tube, after being discharged from the output end of the atmospheric furnace tube, can flow into the regulating valve, and after passing through the regulating valve, can flow into the factory's tail exhaust system through the tail pipe. Furthermore, the reaction gas can flow from the output end of the tail exhaust system into the input end of the exhaust pump, and then flow out from the output end of the exhaust pump and into the atmosphere.

[0071] In some embodiments, the air pressure at the air pump input is It can be related to the factory's tail exhaust system. For the same factory, when the parameters of the tail exhaust system remain unchanged, the air pressure at the input end of the vacuum pump Can be fixed.

[0072] In some embodiments, the thickness of the film can be affected by the operating pressure and the reaction time, and the thickness of the film can be controlled by adjusting the operating pressure and the reaction time. In some embodiments, when the reaction time is kept fixed, since the reaction time remains unchanged, the thickness of the film can change with the change in the operating pressure, and the atmospheric pressure furnace tube pressure coefficient can be -1. In other embodiments, when the operating pressure remains unchanged and the thickness of the film is controlled by adjusting the operating time, the atmospheric pressure furnace tube pressure coefficient can be 0. When the operating time and the operating pressure are adjusted simultaneously to control the thickness of the film, the atmospheric pressure furnace tube pressure coefficient can range from -1 to 0.

[0073] In some embodiments, the air pressure at the output end of the air pump can be the current air pressure of the atmosphere, and the second preset pressure difference can be calculated by the following formula: :

[0074]

[0075] in, The second preset pressure difference may be It can be the air pressure at the output end of the vacuum pump (i.e. the current air pressure of atmospheric pressure), It can be the air pressure at the input end of the vacuum pump.

[0076] Based on the reference air pressure, the current air pressure, the second preset pressure difference, and the first coefficient, the first preset pressure difference of the atmospheric pressure furnace tube can be calculated using the following formula:

[0077]

[0078] Preferably, when the reaction time is kept constant and the thickness of the film is changed by adjusting the gas pressure, the atmospheric pressure coefficient of the furnace tube can be Set to -1, then the first preset pressure difference can be:

[0079]

[0080] According to the above formula, we can see that the current air pressure When lifting, the first preset pressure difference Can reduce current air pressure When the first preset pressure difference is reduced Can be improved.

[0081] In some embodiments, the pressure difference between the first air pressure and the second air pressure satisfies a first preset pressure difference, which can be calculated using the following formula:

[0082]

[0083]

[0084] in, It can be the first air pressure, Can be the second air pressure, It can be a first preset pressure difference, Can be the current air pressure, Can be the air pressure at the input end of the vacuum pump, Can be the reference air pressure.

[0085] When the current air pressure When a change occurs, the formula Middle: Air pressure at the input of the vacuum pump and reference pressure It can be a fixed value, from which you can see the first preset pressure difference Can follow the current air pressure Furthermore, in the above formula, it can be seen that the pressure difference between the first air pressure and the second air pressure can also change with the current air pressure. changes with the changes of .

[0086] It is understandable that by adjusting the pressure difference between the first air pressure and the second air pressure so that the pressure difference between the first air pressure and the second air pressure is equal to the first preset pressure difference, the following formula can be obtained:

[0087]

[0088] It is important to understand that if the current air pressure When changes occur, for example, the current air pressure becomes When the second air pressure can also become . Furthermore, the air pressure at the input and reference air pressure can remain constant, so the first air pressure The same can remain unchanged.

[0089] Through the solution of this application, when preparing thin films in a normal-pressure furnace tube, when the external atmospheric pressure changes, the pressure difference between the first and second pressures can be adjusted to maintain a constant value, so that the first pressure remains constant. This can ensure that the thickness of the prepared thin film has good consistency, thereby improving the accuracy of the product when preparing small-sized, low-linewidth chips. Furthermore, it can also reduce the number of products that do not meet the requirements and improve the yield rate.

[0090] Figure 4 An exemplary block diagram of a method 400 for preparing a thin film in an atmospheric furnace tube based on a first gas pressure and a preset time according to some embodiments of the present application is shown. Figure 4 As shown, method 400 includes: step S401: obtaining historical data of a normal pressure furnace tube, wherein the historical data includes first data on the relationship between film forming pressure, film forming time and film forming thickness; step S402: obtaining a preset time based on the first data, the first gas pressure and the preset film forming thickness; step S403: preparing a thin film in the normal pressure furnace tube based on the first gas pressure and the preset time.

[0091] In some embodiments, the historical data of the atmospheric pressure furnace tube may include partial or complete historical production data of the atmospheric pressure furnace tube, which may include parameters recorded when growing thin films in different production batches and at different factories, and may include the relationship between film forming pressure, film forming time, and film forming thickness. It is understood that a data graph related to film forming thickness can be obtained based on film forming pressure and film forming time.

[0092] In some embodiments, after obtaining the first data and the first pressure, a preset film thickness can be set as needed. Furthermore, the time required for the film to grow to the preset film thickness under the first pressure can be determined from the data graph, and this time can be set as the preset time. By adjusting the pressure difference between the first and second pressures to maintain the first pressure stable, a film can be produced within the atmospheric pressure furnace tube based on the preset time.

[0093] In some embodiments, the atmospheric pressure furnace tube system includes an exhaust device located between the atmospheric pressure furnace tube and the tail pipe, and adjusting the pressure difference between the first air pressure and the second air pressure includes: adjusting the speed of gas circulation in the exhaust device to adjust the pressure difference between the first air pressure and the second air pressure.

[0094] In some embodiments, the aforementioned exhaust device may include a regulating valve. It is understood that the regulating valve can be installed on the tail pipe of the atmospheric pressure furnace tube, and the valve core of the regulating valve can change the flow area between the valve core and the valve seat by moving or rotating, thereby changing the flow rate of gas through the regulating valve to achieve pressure regulation. It is understood that when the flow area between the valve core and the valve seat decreases, the flow rate of gas through the regulating valve decreases, which can increase the pressure inside the atmospheric pressure furnace tube; when the flow area between the valve core and the valve seat increases, the flow rate of gas through the regulating valve increases, which can reduce the pressure inside the atmospheric pressure furnace tube.

[0095] In some embodiments, the position of the valve core of the regulating valve can be adjusted manually. Specifically, the regulating valve can be provided with a rotating hand wheel or a lever to control the valve opening, thereby adjusting the exhaust volume to control the air pressure in the furnace tube.

[0096] In other embodiments, the position of the valve core of the regulating valve can also be adjusted through automatic adjustment. Specifically, the air pressure in the furnace tube can be monitored by a pressure sensor, and the pressure signal can be transmitted to a controller. The controller compares and analyzes the preset pressure value with the actual measured value, and then sends a control signal to the actuator of the regulating valve, which can automatically adjust the opening of the regulating valve to keep the air pressure in the furnace tube within the set range. For example, large-scale atmospheric pressure furnace tube systems in industrial production often adopt this automated adjustment method to ensure the stability of the air pressure in the furnace tube, improve the reliability of the production process and improve product quality.

[0097] By setting up the exhaust device, when the atmospheric pressure changes, the second air pressure can be adjusted by adjusting the exhaust device, so that the first air pressure can be maintained unchanged, thereby maintaining a stable rate of film preparation and accurately controlling the thickness of the silicon dioxide film.

[0098] Figure 5 An exemplary block diagram of an atmospheric furnace tube system according to some embodiments of the present application is shown. Figure 5 As shown, the system includes: a first measuring module, used to obtain the working air pressure inside the atmospheric pressure furnace tube as the first air pressure; a second measuring module, used to obtain the air pressure of the tail pipe of the atmospheric pressure furnace tube as the second air pressure; an adjusting module, used to adjust the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure, so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference, so as to maintain the first air pressure unchanged; a preparation module, used to prepare a thin film in the atmospheric pressure furnace tube based on the first air pressure and a preset time.

[0099] In some embodiments, the aforementioned system may include a first measurement module, a second measurement module, an adjustment module, and a preparation module.

[0100] In some embodiments, the preparation module may include a normal pressure furnace tube body, and the first measurement module may be connected to the normal pressure furnace tube body to measure the working pressure inside the normal pressure furnace tube, which may serve as the first pressure. Furthermore, the first measurement module may include a pressure measurement device.

[0101] In some embodiments, the atmospheric pressure furnace tube body may include an input and an output. Reaction gas may be introduced into the atmospheric pressure furnace tube body through the input. After a thermal oxidation reaction occurs within the atmospheric pressure furnace tube body, the reacted gas may be discharged from the output of the atmospheric pressure furnace tube body. The output of the atmospheric pressure furnace tube body may be connected to a tail pipe, and a second measurement module may be connected to the tail pipe to obtain the tail pipe pressure, which may be used as the second pressure. In some embodiments, the second measurement module may include a pressure measurement device.

[0102] In summary, the present invention has the unexpected technical effect of maintaining a constant working pressure within the atmospheric furnace tube by adjusting the secondary pressure in the tail pipe of the atmospheric furnace tube when atmospheric pressure changes. This allows for a stable film production rate and ensures a consistent thickness of the produced film. Furthermore, when producing small, low-linewidth chips, the accuracy of the product can be improved, thereby increasing the yield rate.

[0103] Although multiple embodiments of the present application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art can conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present application. It should be understood that in the process of practicing the present application, various alternatives to the embodiments of the present application described herein can be adopted. The accompanying claims are intended to define the scope of protection of the present application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for preparing a thin film for an atmospheric pressure furnace tube system, characterized in that: The method comprises: Obtaining the working gas pressure inside the atmospheric pressure furnace tube as the first gas pressure; obtaining the gas pressure of the tail pipe of the atmospheric pressure furnace tube as the second gas pressure; Based on the first air pressure and the second air pressure, adjusting the pressure difference between the first air pressure and the second air pressure so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference, so as to maintain the first air pressure unchanged; Based on the first gas pressure and the preset time, a thin film is prepared in the atmospheric pressure furnace tube, The working pressure is the pressure in the area where the wafer is located inside the atmospheric pressure furnace tube; Before adjusting the pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference, the method further includes: Obtaining the lowest atmospheric pressure within a preset period as a reference pressure; Get the current value of atmospheric pressure as the current air pressure; Based on the reference air pressure and the current air pressure, a first preset pressure difference of the atmospheric pressure furnace tube is calculated.

2. The method according to claim 1, wherein the atmospheric pressure furnace tube system comprises an air extraction pump, the input end of the air extraction pump is connected to the tail pipe of the atmospheric pressure furnace tube, and the output end of the air extraction pump is connected to the atmosphere, characterized in that: The calculating of the first preset pressure difference of the atmospheric pressure furnace tube based on the reference air pressure and the current air pressure includes: Setting the pressure difference between the output end and the input end of the vacuum pump to a second preset pressure difference; Obtaining the atmospheric pressure coefficient of the furnace tube as the first coefficient; A first preset pressure difference of the atmospheric pressure furnace tube is calculated based on the reference air pressure, the current air pressure, the second preset pressure difference, and the first coefficient.

3. The method according to claim 1, characterized in that The step of preparing a thin film in the atmospheric pressure furnace tube based on the first gas pressure and the preset time includes: Obtaining historical data of a normal pressure furnace tube, wherein the historical data includes first data on a relationship between film forming pressure, film forming time, and film forming thickness; Obtaining a preset time based on the first data, the first air pressure, and a preset film thickness; Based on the first gas pressure and the preset time, a thin film is prepared in the atmospheric pressure furnace tube.

4. The method according to claim 1, wherein The atmospheric pressure furnace tube system includes an exhaust device located between the atmospheric pressure furnace tube and the tail pipe. Adjusting the pressure difference between the first air pressure and the second air pressure includes: adjusting the speed of gas circulation in the exhaust device to adjust the pressure difference between the first air pressure and the second air pressure.

5. The method according to claim 1, wherein The atmospheric pressure furnace tube includes a horizontal atmospheric pressure furnace tube or a vertical atmospheric pressure furnace tube.

6. The method according to claim 1, characterized in that A wafer boat is arranged in the atmospheric pressure furnace tube, and the wafer boat is used for storing wafers so as to form a thin film on the surface of the wafer.

7. The method according to claim 1, characterized in that The thin film includes at least one of a gate oxide layer, a diffusion layer, and an epitaxial layer.

8. An atmospheric pressure furnace tube system, characterized in that: When the atmospheric pressure furnace tube system is used to prepare a thin film, the method according to any one of claims 1 to 7 is performed, wherein the system comprises: A first measuring module is used to obtain the working gas pressure inside the atmospheric pressure furnace tube as the first gas pressure; The second measuring module is used to obtain the gas pressure of the tail pipe of the atmospheric pressure furnace tube as the second gas pressure; an adjustment module, configured to adjust a pressure difference between the first air pressure and the second air pressure based on the first air pressure and the second air pressure, so that the pressure difference between the first air pressure and the second air pressure is equal to a first preset pressure difference, thereby maintaining the first air pressure unchanged; A preparation module is used to prepare a thin film in the atmospheric pressure furnace tube based on the first gas pressure and a preset time.

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