Epitaxial growth apparatus and temperature control method thereof

Abstract

The application provides an epitaxial growth device and a temperature control method thereof, and belongs to the technical field of semiconductor manufacturing. The epitaxial growth device comprises: an upper quartz bell jar and a lower quartz bell jar, the upper quartz bell jar and the lower quartz bell jar are arranged to form a reaction chamber; a susceptor for placing a silicon wafer in the reaction chamber; a heating module in the reaction chamber, the heating module comprises an upper heating module arranged above the susceptor and a lower heating module arranged below the susceptor; a temperature measurement assembly for obtaining the temperature of the upper surface of the silicon wafer and the temperature of the susceptor; a power measurement assembly for obtaining the power of the heating module; and a control unit for judging whether to perform a cleaning step according to the temperature of the upper surface of the silicon wafer, the temperature of the susceptor and the power of the heating module, and cleaning the upper quartz bell jar and / or the lower quartz bell jar. The technical scheme of the application can control the temperature of epitaxial growth and ensure the quality of epitaxial products.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to an epitaxial growth apparatus and its temperature control method. Background Technology

[0002] The production of silicon wafers typically involves processes such as crystal pulling, shaping, polishing, cleaning, and epitaxy. With the rapid development of the integrated circuit industry, the requirements for substrates are becoming increasingly stringent, such as the thickness, flatness, resistivity, and surface particles of the epitaxial layer.

[0003] Epitaxial growth of silicon wafers is a crucial process in semiconductor chip manufacturing. This process involves growing an epitaxial layer on a polished silicon wafer under specific conditions, with controllable resistivity and thickness, free of crystal-originated particles (COP) defects and oxygen deposits. Epitaxial growth of silicon wafers primarily includes vacuum epitaxial deposition, vapor phase epitaxial deposition, and liquid phase epitaxial deposition, with vapor phase epitaxial deposition being the most widely used.

[0004] Vapor phase epitaxy (VPE) equipment generally includes: an upper quartz bell jar, a lower quartz bell jar, an inlet, an outlet, and mounting components. The reaction chamber enclosed by the upper and lower quartz bell jars contains a base for placing silicon wafers, base support rods, and wafer support rods. After the silicon wafer is fed into the reaction chamber and placed on the base, it is heated by an upper heating module located on the upper side and a lower heating module located on the lower side of the base. Raw material gases are supplied to the surface of the silicon wafer, thereby performing vapor phase epitaxy. The resulting epitaxial wafer is then output outside the reaction chamber. During the growth process, the base support rods serve to fix the base and rotate it, ensuring uniform epitaxial growth on the substrate.

[0005] In actual epitaxial growth, if the epitaxial layer deposition temperature changes, the epitaxial wafer will slip, and parameters such as flatness and resistivity will also change, affecting product quality. However, existing technologies cannot effectively control the temperature of epitaxial growth. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an epitaxial growth apparatus and its temperature control method, which can control the temperature of epitaxial growth and ensure the quality of epitaxial products.

[0007] To achieve the above objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0008] A temperature control method for an epitaxial growth apparatus, the epitaxial growth apparatus comprising:

[0009] An upper quartz bell jar and a lower quartz bell jar are arranged to form a reaction chamber;

[0010] A base located within the reaction chamber for placing silicon wafers;

[0011] A heating module located within the reaction chamber, the heating module comprising an upper heating module disposed above the base and a lower heating module disposed below the base;

[0012] The temperature control method is characterized by comprising:

[0013] The temperature of the upper surface of the silicon wafer and the temperature of the base are obtained using a temperature measurement component;

[0014] The power of the heating module is obtained using a power measurement component;

[0015] Based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, it is determined whether to perform a cleaning step to clean the upper quartz bell jar and / or the lower quartz bell jar.

[0016] In some embodiments, after performing the cleaning step, the method further includes:

[0017] The thermal emissivity of the heating module is adjusted based on the temperature of the upper surface of the silicon wafer and the temperature of the base.

[0018] In some embodiments, determining whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module includes:

[0019] When the temperature difference between the upper surface and the base is greater than a preset threshold, and the total power of the heating module shows an upward trend, the cleaning step is determined to be executed.

[0020] The total power of the heating module shows an increasing trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage.

[0021] In some embodiments, adjusting the thermal emissivity of the heating module based on the temperature of the upper surface of the silicon wafer and the temperature of the base includes:

[0022] When the temperature of the upper surface is greater than the temperature of the base, the thermal emissivity of the upper heating module is increased; when the temperature of the upper surface is less than the temperature of the base, the thermal emissivity of the lower heating module is increased.

[0023] In some embodiments, the cleaning step includes:

[0024] After the silicon wafer is removed from the reaction chamber, the reaction chamber is purged.

[0025] The reaction chamber is heated to 1160-1180℃;

[0026] The reaction chamber was baked with hydrogen gas;

[0027] Etching gas is delivered to the reaction chamber to etch the quartz bell jar to be cleaned;

[0028] The reaction chamber is purged to remove the etching products.

[0029] The reaction chamber is cooled.

[0030] This invention also provides an epitaxial growth apparatus, comprising:

[0031] An upper quartz bell jar and a lower quartz bell jar are arranged to form a reaction chamber;

[0032] A base located within the reaction chamber for placing silicon wafers;

[0033] A heating module located within the reaction chamber, the heating module comprising an upper heating module disposed above the base and a lower heating module disposed below the base;

[0034] The epitaxial growth apparatus also includes:

[0035] A temperature measurement component is used to acquire the temperature of the upper surface of the silicon wafer and the temperature of the base;

[0036] A power measurement component is used to acquire the power of the heating module;

[0037] The control unit is used to determine whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, and to clean the upper quartz bell jar and / or the lower quartz bell jar.

[0038] In some embodiments, the control unit is further configured to adjust the thermal emissivity of the heating module based on the temperature of the upper surface of the silicon wafer and the temperature of the base after performing the cleaning step.

[0039] In some embodiments, the control unit is specifically used to determine to execute the cleaning step when the difference between the temperature of the upper surface and the temperature of the base is greater than a preset threshold and the total power of the heating module shows an upward trend.

[0040] The total power of the heating module shows an increasing trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage.

[0041] In some embodiments, the control unit is specifically used to clean the lower quartz bell jar when the temperature of the upper surface is greater than the temperature of the base; and to clean the upper quartz bell jar when the temperature of the upper surface is less than the temperature of the base.

[0042] In some embodiments, the control unit is specifically configured to increase the thermal emissivity of the upper heating module when the temperature of the upper surface is greater than the temperature of the base, and to increase the thermal emissivity of the lower heating module when the temperature of the upper surface is less than the temperature of the base.

[0043] The beneficial effects of this invention are:

[0044] During epitaxial growth, deposits on the upper or lower quartz bell jar can cause a temperature difference between the upper and lower surfaces of the silicon wafer, leading to a change in the epitaxial layer deposition temperature. However, this temperature difference is not necessarily caused by deposits on the quartz bell jar; it could indicate a calibration anomaly requiring recalibration. Experiments have shown that when deposits appear on the quartz bell jar, not only does a temperature difference occur between the upper and lower surfaces of the silicon wafer, but the total power of the heating module also increases. Therefore, when a temperature difference occurs between the upper and lower surfaces of the silicon wafer, and the total power of the heating module increases, it can be determined that the change in the epitaxial layer deposition temperature is caused by deposits on the quartz bell jar. In this embodiment, the temperature of the upper surface of the silicon wafer and the temperature of the base (which can reflect the temperature of the lower surface of the silicon wafer) can be obtained through a temperature measurement component. Based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, it can be accurately determined whether there are deposits on the quartz bell jar. When it is determined that there are deposits on the quartz bell jar, the quartz bell jar can be cleaned to avoid changes in the epitaxial layer deposition temperature, thereby controlling the temperature of epitaxial growth and ensuring the quality of epitaxial products. Attached Figure Description

[0045] Figure 1 This diagram illustrates the structure of the epitaxial growth apparatus according to an embodiment of the present invention.

[0046] Figure 2 A schematic flowchart illustrating the temperature control method of the epitaxial growth equipment according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram illustrating the process of controlling the temperature of the epitaxial growth equipment in a specific example of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0049] This invention provides an epitaxial growth device and its temperature control method, which can control the temperature of epitaxial growth and ensure the quality of epitaxial products.

[0050] During epitaxial growth, deposits on the upper or lower quartz bell jar can cause a temperature difference between the upper and lower surfaces of the silicon wafer. This leads to changes in the epitaxial layer deposition temperature, causing wafer slippage and altering parameters such as flatness and resistivity, thus affecting product quality. To avoid this, when a temperature difference occurs between the upper and lower surfaces of the silicon wafer, the machine can be stopped, the upper and lower quartz bell jars opened, and cleaned with an acid solution. However, this cleaning method is time-consuming and labor-intensive, severely impacting normal production. Furthermore, the temperature difference between the upper and lower surfaces of the silicon wafer is not necessarily caused by deposits on the quartz bell jar; it could be due to an abnormal temperature calibration requiring recalibration.

[0051] This invention provides an epitaxial growth apparatus, such as... Figure 1 As shown, it includes:

[0052] The upper quartz bell jar 1 and the lower quartz bell jar 2 are fixed together by mounting components 7 to form a reaction chamber.

[0053] A base 8 located within the reaction chamber for placing silicon wafers;

[0054] The heating module located in the reaction chamber includes an upper heating module disposed above the base 8 and a lower heating module disposed below the base;

[0055] Specifically, the heating module can be implemented using a halogen lamp 3, and the reaction chamber is also equipped with a base support rod 4, a pin 5, a pin support rod 6 and a preheating ring 9 for supporting the base 8.

[0056] The epitaxial growth apparatus also includes:

[0057] A temperature measurement component is used to acquire the temperature of the upper surface of the silicon wafer and the temperature of the base. Specifically, the temperature measurement component may include a first thermometer 10 near the base for acquiring the temperature of the base, and a second thermometer 11 near the upper surface of the silicon wafer for acquiring the temperature of the upper surface of the silicon wafer. The temperature of the upper surface of the silicon wafer can be calculated based on the temperature measured by the second thermometer 11 and the distance between the second thermometer 11 and the silicon wafer, and the temperature of the base can be calculated based on the temperature measured by the first thermometer 10 and the distance between the first thermometer 10 and the base. The temperature of the base can characterize the temperature of the lower surface of the silicon wafer. When the silicon wafer enters the reaction chamber and is placed on the base 8, the temperature of the upper surface of the silicon wafer and the temperature of the base can be acquired in real time through the second thermometer 11 and the first thermometer 10.

[0058] A power measurement component is used to acquire the power of the heating module;

[0059] The control unit is used to determine whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, and to clean the upper quartz bell jar and / or the lower quartz bell jar.

[0060] During epitaxial growth, deposits on the upper or lower quartz bell jar can cause a temperature difference between the upper and lower surfaces of the silicon wafer, leading to a change in the epitaxial layer deposition temperature. However, this temperature difference is not necessarily caused by deposits on the quartz bell jar; it could indicate a calibration anomaly requiring recalibration. Experiments have shown that when deposits appear on the quartz bell jar, not only does a temperature difference occur between the upper and lower surfaces of the silicon wafer, but the total power of the heating module also increases. Therefore, when a temperature difference occurs between the upper and lower surfaces of the silicon wafer, and the total power of the heating module increases, it can be determined that the change in the epitaxial layer deposition temperature is caused by deposits on the quartz bell jar.

[0061] In this embodiment, the determination is not only based on the temperature of the upper surface of the silicon wafer and the temperature of the substrate (which reflects the temperature of the lower surface of the silicon wafer), but also on the power of the heating module. This allows for accurate detection of deposits on the quartz bell jar. When deposits are present, the quartz bell jar can be cleaned to prevent changes in the epitaxial layer deposition temperature, thereby controlling the epitaxial growth temperature and ensuring the quality of the epitaxial product. Furthermore, this embodiment only cleans the quartz bell jar when deposits are confirmed, avoiding unnecessary downtime and ensuring normal production. This embodiment offers high efficiency and accuracy in controlling the epitaxial growth temperature, while avoiding the inconvenience caused by downtime.

[0062] In this embodiment, when it is determined that a cleaning step needs to be performed, the cleaning step can be performed after the silicon wafer is removed from the reaction chamber after the epitaxial growth is completed.

[0063] Specifically, the control unit is used to determine to execute the cleaning step when the difference between the temperature of the upper surface and the temperature of the base is greater than a preset threshold and the total power of the heating module is increasing.

[0064] The total power of the heating module shows an increasing trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage.

[0065] When the epitaxial growth equipment is operating, silicon wafers are placed into the reaction chamber to perform the epitaxial growth stage. After epitaxial growth is completed, the silicon wafers are removed, and the chamber cleaning stage is performed. Then, the next batch of silicon wafers is placed into the reaction chamber to perform the epitaxial growth stage, and after epitaxial growth is completed, the silicon wafers are removed, and the chamber cleaning stage is performed; and so on. If, in two consecutive epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage, it can be determined that the total power of the heating module is increasing. Similarly, if, in two consecutive chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage, it can also be determined that the total power of the heating module is increasing.

[0066] When the temperature difference between the upper and lower surfaces of the silicon wafer exceeds a preset threshold, it indicates a change in the epitaxial layer deposition temperature. If the total power of the heating module also shows an upward trend, it can be determined that the change in the epitaxial layer deposition temperature is caused by deposits on the quartz bell jar. In this embodiment, based on the temperature difference between the upper and lower surfaces of the silicon wafer and the upward trend of the heating module's power, it can be accurately determined whether there are deposits on the quartz bell jar. Specifically, the preset threshold can be 5°C, meaning that when the temperature difference between the upper and lower surfaces of the silicon wafer is greater than 5°C and the total power of the heating module shows an upward trend, it can be determined that there are deposits on the quartz bell jar.

[0067] Experiments have verified that when deposits appear on the lower quartz bell jar, the temperature of the upper surface of the silicon wafer is higher than the temperature of the base; when deposits appear on the upper quartz bell jar, the temperature of the upper surface of the silicon wafer is lower than the temperature of the base. Therefore, after determining that there are deposits on the quartz bell jar, it can be further determined whether the deposits are on the upper or lower quartz bell jar based on the temperature of the upper surface of the silicon wafer and the temperature of the base. If the temperature of the upper surface is higher than the temperature of the base, it can be determined that there are deposits on the lower quartz bell jar; if the temperature of the upper surface is lower than the temperature of the base, it can be determined that there are deposits on the upper quartz bell jar. Specifically, the control unit is used to clean the lower quartz bell jar when the temperature of the upper surface is higher than the temperature of the base, and to clean the upper quartz bell jar when the temperature of the upper surface is lower than the temperature of the base.

[0068] In this embodiment, the cleaning step includes:

[0069] The reaction chamber is purged. Specifically, the reaction chamber can be purged with hydrogen at a temperature of 850°C, and the flow rate of hydrogen can be 6 slm.

[0070] The reaction chamber is heated to 1160-1180°C. Specifically, the heating rate can be 3°C / s, and the hydrogen flow rate can be 6 slm.

[0071] The reaction chamber is baked with hydrogen gas, specifically, the flow rate of hydrogen gas can be 6 slm;

[0072] Etching gas is delivered to the reaction chamber to etch the quartz bell jar to be cleaned. Specifically, the etching gas can be HCl, and hydrogen gas is continuously introduced into the reaction chamber at a flow rate of 6 slm and HCl flow rate of 3 slm. In this embodiment, the etching gas can be controlled to etch only the deposits on the quartz bell jar to be cleaned by controlling the flow path of the etching gas. Specifically, the flow path of the etching gas can be controlled by changing the height of the base.

[0073] The reaction chamber is purged to remove the etched products. The reaction chamber can be purged with hydrogen at a temperature of 1150°C and the flow rate of hydrogen can be 8 slm. This high flow rate of hydrogen ensures that the etched products are removed from the reaction chamber.

[0074] The reaction chamber is cooled, specifically at a rate of 9°C / s. Simultaneously, hydrogen gas is continuously introduced into the reaction chamber during the cooling process, with a flow rate of 6 slm.

[0075] In related technologies, it is necessary to stop the machine, open the cavity to remove the quartz bell jar, and then clean the quartz bell jar with an acid solution. In this embodiment, the quartz bell jar can be cleaned without stopping the machine, opening the cavity to remove the quartz bell jar, which can speed up the production cycle and improve the production efficiency of epitaxial products.

[0076] In some embodiments, after the cleaning step, when epitaxial growth is performed again, the temperature of the upper surface of the silicon wafer and the temperature of the substrate may change. The temperature measurement components can be used again to obtain the temperatures of the upper surface of the silicon wafer and the substrate to determine if a temperature difference exists. If a temperature difference exists, the control unit can adjust the thermal emissivity of the heating module based on the temperatures of the upper surface of the silicon wafer and the substrate to reduce the temperature difference, prevent changes in the epitaxial layer deposition temperature, and thus control the epitaxial growth temperature to ensure the quality of the epitaxial product.

[0077] In this embodiment, the thermal emissivity of the heating module can be adjusted during the epitaxial growth stage, or a dedicated silicon wafer growth test stage can be set up to adjust the thermal emissivity of the heating module during the silicon wafer growth test stage.

[0078] In this embodiment, the upper heating module mainly heats the upper surface of the silicon wafer, and the lower heating module mainly heats the base. The relationship between the thermal emissivity and temperature of the heating module is: E = r / T, where r is a constant, E is the thermal emissivity of the heating module, and T is the temperature of the heating module. It can be seen that the thermal emissivity of the heating module is inversely proportional to the temperature. The smaller the thermal emissivity, the higher the temperature; the larger the thermal emissivity, the lower the temperature.

[0079] In some embodiments, the control unit is specifically configured to, when the temperature of the upper surface is greater than the temperature of the base, increase the thermal emissivity of the upper heating module, thereby reducing the temperature of the upper heating module, and thus reducing the temperature difference between the upper and lower surfaces of the silicon wafer, preventing changes in the epitaxial layer deposition temperature, and thereby controlling the epitaxial growth temperature to ensure the quality of the epitaxial product; and when the temperature of the upper surface is less than the temperature of the base, increase the thermal emissivity of the lower heating module, thereby reducing the temperature of the lower heating module, and thus reducing the temperature difference between the upper and lower surfaces of the silicon wafer, preventing changes in the epitaxial layer deposition temperature, and thereby controlling the epitaxial growth temperature to ensure the quality of the epitaxial product.

[0080] This invention also provides a temperature control method for an epitaxial growth apparatus, applied to the epitaxial growth apparatus described above, such as... Figure 2 As shown, the temperature control method includes:

[0081] Step 101: Use a temperature measuring component to obtain the temperature of the upper surface of the silicon wafer and the temperature of the base;

[0082] Step 102: Obtain the power of the heating module using a power measurement component;

[0083] Step 103: Based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, determine whether to perform a cleaning step and clean the upper quartz bell jar and / or the lower quartz bell jar.

[0084] During epitaxial growth, deposits on the upper or lower quartz bell jar can cause a temperature difference between the upper and lower surfaces of the silicon wafer, leading to a change in the epitaxial layer deposition temperature. However, this temperature difference is not necessarily caused by deposits on the quartz bell jar; it could indicate a calibration anomaly requiring recalibration. Experiments have shown that when deposits appear on the quartz bell jar, not only does a temperature difference occur between the upper and lower surfaces of the silicon wafer, but the total power of the heating module also increases. Therefore, when a temperature difference occurs between the upper and lower surfaces of the silicon wafer, and the total power of the heating module increases, it can be determined that the change in the epitaxial layer deposition temperature is caused by deposits on the quartz bell jar.

[0085] In this embodiment, the determination is not based solely on the temperature of the upper surface of the silicon wafer and the temperature of the substrate (which reflects the temperature of the lower surface of the silicon wafer), but also on the power of the heating module. This allows for accurate detection of deposits on the quartz bell jar. When deposits are present, the quartz bell jar can be cleaned to prevent changes in the epitaxial layer deposition temperature, thereby controlling the epitaxial growth temperature and ensuring the quality of the epitaxial product. Furthermore, this embodiment only cleans the quartz bell jar when deposits are confirmed, avoiding unnecessary downtime and ensuring normal production. This provides high efficiency and accuracy in controlling the epitaxial growth temperature, while avoiding the inconvenience caused by downtime.

[0086] In this embodiment, when it is determined that a cleaning step needs to be performed, the cleaning step can be performed after the silicon wafer is removed from the reaction chamber after the epitaxial growth is completed.

[0087] In some embodiments, determining whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module includes:

[0088] When the temperature difference between the upper surface and the base is greater than a preset threshold, and the total power of the heating module shows an upward trend, the cleaning step is determined to be executed.

[0089] The total power of the heating module shows an increasing trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage.

[0090] When the epitaxial growth equipment is operating, silicon wafers are placed into the reaction chamber to perform the epitaxial growth stage. After epitaxial growth is completed, the silicon wafers are removed, and the chamber cleaning stage is performed. Then, the next batch of silicon wafers is placed into the reaction chamber to perform the epitaxial growth stage, and after epitaxial growth is completed, the silicon wafers are removed, and the chamber cleaning stage is performed; and so on. If, in two consecutive epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage, it can be determined that the total power of the heating module is increasing. Similarly, if, in two consecutive chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage, it can also be determined that the total power of the heating module is increasing.

[0091] When the temperature difference between the upper and lower surfaces of the silicon wafer exceeds a preset threshold, it indicates a change in the epitaxial layer deposition temperature. When the total power of the heating module shows an upward trend, it can be determined that the change in epitaxial layer deposition temperature is caused by deposits on the quartz bell jar. In this embodiment, based on the temperature difference between the upper and lower surfaces of the silicon wafer and the upward trend of the heating module's power, it can be accurately determined whether there are deposits on the quartz bell jar. Specifically, the preset threshold can be 5°C; that is, when the temperature difference between the upper and lower surfaces of the silicon wafer is greater than 5°C and the total power of the heating module shows an upward trend, it can be determined that there are deposits on the quartz bell jar.

[0092] After determining that there are deposits in the quartz bell jar, the temperature of the upper surface of the silicon wafer and the temperature of the base can be used to further determine whether the deposits are in the upper or lower quartz bell jar. If the temperature of the upper surface is greater than the temperature of the base, it can be determined that there are deposits in the lower quartz bell jar; if the temperature of the upper surface is less than the temperature of the base, it can be determined that there are deposits in the upper quartz bell jar. Specifically, the control unit is used to clean the lower quartz bell jar when the temperature of the upper surface is greater than the temperature of the base, and to clean the upper quartz bell jar when the temperature of the upper surface is less than the temperature of the base.

[0093] In some embodiments, after performing the cleaning step, the method further includes:

[0094] The thermal emissivity of the heating module is adjusted based on the temperature of the upper surface of the silicon wafer and the temperature of the base.

[0095] After the cleaning step, during the subsequent epitaxial growth, the temperature of the upper surface of the silicon wafer and the temperature of the substrate may change. Temperature measurement components can be used again to obtain the temperatures of the upper surface of the silicon wafer and the substrate to determine if a temperature difference exists. If a temperature difference exists, the control unit can adjust the thermal emissivity of the heating module based on the temperatures of the upper surface of the silicon wafer and the substrate to reduce the temperature difference, prevent changes in the epitaxial layer deposition temperature, and thus control the epitaxial growth temperature to ensure the quality of the epitaxial product.

[0096] In this embodiment, the upper heating module mainly heats the upper surface of the silicon wafer, and the lower heating module mainly heats the base. The relationship between the thermal emissivity and temperature of the heating module is: E = r / T, where r is a constant, E is the thermal emissivity of the heating module, and T is the temperature of the heating module. It can be seen that the thermal emissivity of the heating module is inversely proportional to the temperature. The smaller the thermal emissivity, the higher the temperature; the larger the thermal emissivity, the lower the temperature.

[0097] In some embodiments, adjusting the thermal emissivity of the heating module based on the temperature of the upper surface of the silicon wafer and the temperature of the base includes:

[0098] When the temperature of the upper surface is greater than the temperature of the base, the thermal emissivity of the upper heating module is increased, thereby reducing the temperature of the upper heating module, which in turn reduces the temperature difference between the upper and lower surfaces of the silicon wafer, preventing changes in the epitaxial layer deposition temperature, and thus controlling the epitaxial growth temperature to ensure the quality of the epitaxial product. When the temperature of the upper surface is less than the temperature of the base, the thermal emissivity of the lower heating module is increased, thereby reducing the temperature of the lower heating module, which in turn reduces the temperature difference between the upper and lower surfaces of the silicon wafer, preventing changes in the epitaxial layer deposition temperature, and thus controlling the epitaxial growth temperature to ensure the quality of the epitaxial product.

[0099] In a specific example, such as Figure 3 As shown, the temperature control method for the epitaxial growth equipment in this embodiment includes the following steps:

[0100] The silicon wafer enters the reaction chamber of the epitaxial growth equipment for epitaxial growth;

[0101] The temperature T1 on the upper surface of the silicon wafer and the temperature T2 of the base are measured in real time using a temperature measurement component.

[0102] Determine if the total power of the heating module shows an upward trend. If so, determine if the temperature difference between T1 and T2 is greater than 5 degrees Celsius. If the temperature difference between T1 and T2 is greater than 5 degrees Celsius, determine if T1 is greater than T2. ​​If T1 is greater than T2, clean the lower quartz bell jar to remove deposits. If T1 is less than T2, clean the upper quartz bell jar to remove deposits. If the temperature difference between T1 and T2 is not greater than 5 degrees Celsius, then normal production can proceed.

[0103] After cleaning the upper or lower quartz bell jar, the temperature T3 of the upper surface of the silicon wafer and the temperature T4 of the base can be measured again during the silicon wafer test growth stage. The thermal emissivity of the heating module can be adjusted according to the temperature T3 of the upper surface of the silicon wafer and the temperature T4 of the base to further reduce the temperature difference.

[0104] In addition, if the total power of the heating module does not show an upward trend, it can be determined that the temperature difference is not caused by deposits on the quartz bell jar. The thermal emissivity of the heating module can be adjusted to reduce the temperature difference.

[0105] In this embodiment, when cleaning the quartz bell jar, the reaction chamber can be purged first. Specifically, after the silicon wafer is removed from the reaction chamber, the reaction chamber can be purged with hydrogen at a temperature of 850°C, and the flow rate of the hydrogen can be 6 slm.

[0106] The reaction chamber is then heated to 1160-1180°C. Specifically, the heating rate can be 3°C / s, and the hydrogen flow rate can be 6 slm.

[0107] The reaction chamber is then baked with hydrogen gas, specifically, the flow rate of hydrogen gas can be 6 slm.

[0108] Etching gas is delivered to the reaction chamber to etch the quartz bell jar to be cleaned. Specifically, the etching gas can be HCl, and hydrogen gas is continuously introduced into the reaction chamber at a flow rate of 6 slm and HCl flow rate of 3 slm. In this embodiment, the etching gas can be controlled to etch only the deposits on the quartz bell jar to be cleaned by controlling the flow path of the etching gas. Specifically, the flow path of the etching gas can be controlled by changing the height of the base.

[0109] The reaction chamber is purged to remove the etched products. The reaction chamber can be purged with hydrogen at a temperature of 1150°C and the flow rate of hydrogen can be 8 slm. This high flow rate of hydrogen ensures that the etched products are removed from the reaction chamber.

[0110] The reaction chamber is cooled, specifically at a rate of 9°C / s. Simultaneously, hydrogen gas is continuously introduced into the reaction chamber during the cooling process, with a flow rate of 6 slm.

[0111] In related technologies, it is necessary to stop the machine, open the cavity to remove the quartz bell jar, and then clean the quartz bell jar with an acid solution. In this embodiment, it is not necessary to stop the machine, open the cavity to remove the quartz bell jar. The quartz bell jar can be cleaned through the above steps, which can speed up the production cycle and improve the production efficiency of epitaxial products.

[0112] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0113] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0114] It is understandable that when a component such as a layer, film, region, or substrate is referred to as being "above" or "below" another component, the component may be "directly" located "above" or "below" the other component, or there may be intermediate components present.

[0115] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0116] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims. 。

Claims

1. A temperature control method for an epitaxial growth apparatus, the epitaxial growth apparatus comprising: An upper quartz bell jar and a lower quartz bell jar are arranged to form a reaction chamber; A base located within the reaction chamber for placing silicon wafers; A heating module located within the reaction chamber, the heating module comprising an upper heating module disposed above the base and a lower heating module disposed below the base; The temperature control method is characterized by comprising: The temperature of the upper surface of the silicon wafer and the temperature of the base are obtained using a temperature measurement component; The power of the heating module is obtained using a power measurement component; Based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, determine whether to perform a cleaning step and clean the upper or lower quartz bell jar. The step of determining whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module includes: When the temperature difference between the upper surface and the base is greater than a preset threshold, and the total power of the heating module shows an upward trend, the cleaning step is determined to be executed. The total power of the heating module shows an upward trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage. The cleaning of the upper or lower quartz bell jar includes: The lower quartz bell jar is cleaned when the temperature of the upper surface is greater than that of the base; the upper quartz bell jar is cleaned when the temperature of the upper surface is less than that of the base.

2. The temperature control method for the epitaxial growth equipment according to claim 1, characterized in that, After performing the cleaning step, the method further includes: The thermal emissivity of the heating module is adjusted based on the temperature of the upper surface of the silicon wafer and the temperature of the base.

3. The temperature control method for the epitaxial growth equipment according to claim 2, characterized in that, The adjustment of the thermal emissivity of the heating module based on the temperature of the upper surface of the silicon wafer and the temperature of the base includes: When the temperature of the upper surface is greater than the temperature of the base, the thermal emissivity of the upper heating module is increased; when the temperature of the upper surface is less than the temperature of the base, the thermal emissivity of the lower heating module is increased.

4. The temperature control method for the epitaxial growth equipment according to claim 1, characterized in that, The cleaning steps include: After the silicon wafer is removed from the reaction chamber, the reaction chamber is purged. The reaction chamber is heated to 1160-1180℃; The reaction chamber was baked with hydrogen gas; Etching gas is delivered to the reaction chamber to etch the quartz bell jar to be cleaned; The reaction chamber is purged to remove the etching products. The reaction chamber is cooled.

5. An epitaxial growth apparatus, comprising: An upper quartz bell jar and a lower quartz bell jar are arranged to form a reaction chamber; A base located within the reaction chamber for placing silicon wafers; A heating module located within the reaction chamber, the heating module comprising an upper heating module disposed above the base and a lower heating module disposed below the base; The epitaxial growth apparatus is characterized in that it further includes: A temperature measurement component is used to acquire the temperature of the upper surface of the silicon wafer and the temperature of the base; A power measurement component is used to acquire the power of the heating module; The control unit is used to determine whether to perform a cleaning step based on the temperature of the upper surface of the silicon wafer, the temperature of the base, and the power of the heating module, and to clean the upper or lower quartz bell jar. The control unit is specifically used to determine to execute the cleaning step when the difference between the temperature of the upper surface and the temperature of the base is greater than a preset threshold and the total power of the heating module is increasing. The total power of the heating module shows an increasing trend as follows: in two adjacent epitaxial growth stages, the total power of the heating module in the second epitaxial growth stage is greater than the total power of the heating module in the first epitaxial growth stage; and / or, in two adjacent chamber cleaning stages, the total power of the heating module in the second chamber cleaning stage is greater than the total power of the heating module in the first chamber cleaning stage. The control unit is specifically used to clean the lower quartz bell jar when the temperature of the upper surface is greater than the temperature of the base; and to clean the upper quartz bell jar when the temperature of the upper surface is less than the temperature of the base.

6. The epitaxial growth apparatus according to claim 5, characterized in that, The control unit is also configured to adjust the thermal emissivity of the heating module based on the temperature of the upper surface of the silicon wafer and the temperature of the base after the cleaning step is performed.

7. The epitaxial growth apparatus according to claim 6, characterized in that, The control unit is specifically used to increase the thermal emissivity of the upper heating module when the temperature of the upper surface is greater than the temperature of the base; and to increase the thermal emissivity of the lower heating module when the temperature of the upper surface is less than the temperature of the base.

Images