A method for reducing particles in furnace tubes

Abstract

The present application provides a method for reducing particles within a furnace tube, wherein the method comprises: performing a first cooling operation on the wafers after a thermal reaction process in a thermal reaction chamber of the furnace tube according to a first preset cooling condition, so as to control the temperature of the wafers to drop to the first preset temperature; after the first cooling operation is performed, performing a second cooling operation on the wafers according to a second preset cooling condition, so as to control the temperature of the wafers to drop to the second preset temperature; after the second cooling operation is performed, controlling the rotation of a wafer boat loaded with wafers to stop according to a preset rotation stop condition. The present application solves the technical problem of the prior art that particles are easily generated within the furnace tube, achieving the technical effect of reducing particles generated by wafer deformation and reducing particles generated by friction between the wafer and the wafer boat.

Description

Technical Field

[0001] The present application relates to the field of semiconductor process technology, and in particular to a method for reducing particles in a furnace tube. Background Art

[0002] In semiconductor manufacturing, the furnace tube process is a key process, capable of batch processing and primarily used in thermal reaction processes such as thermal oxidation, thermal annealing, thermal baking, and chemical vapor deposition. The furnace tube process can be used to grow thin films on wafers. Typically, the wafer is placed in the slots of a wafer boat, which is then placed into the thermal reaction chamber of the furnace tube. Conditions are applied to the furnace tube, such as heating and the introduction of reactive gases, to produce the thin film.

[0003] The thermal reaction process raises the temperature of the wafer. After the thermal reaction is complete, the wafer needs to be cooled from the high temperature to room temperature. The drastic change in temperature increases the thermal stress deformation of the wafer, causing relative displacement between the wafer and the wafer boat slot. During the thermal deformation process, the back of the wafer and the wafer boat slot rub against each other, generating a large number of 2-5 micron (μm) block particles. Under the influence of the airflow in the thermal reaction chamber, these block particles move to the surface of other product wafers, or some of the surface block particles directly fall onto the surface of the wafer placed in the next slot, thereby affecting the stability of the subsequent wafer processing and, in turn, the wafer yield. Summary of the Invention

[0004] In view of this, the purpose of the present application is to at least provide a method for reducing particles in the furnace tube, by performing segmented cooling on the wafer after the thermal reaction process, so as to ensure the cooling efficiency for the wafer during the first cooling process, reduce the wafer deformation caused by cooling during the second cooling process and prevent the wafer from being reheated, and control the wafer boat to gradually stop rotating after the segmented cooling, so as to prevent the friction between the wafer and the wafer boat due to inertia during the rotation and generate particles, thereby solving the technical problem of easy generation of particles inside the furnace tube in the prior art, and achieving the technical effect of reducing particles generated by wafer deformation and reducing particles generated by friction between the wafer and the wafer boat.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides a method for reducing particles in a furnace tube, the method comprising: performing a first cooling operation on the wafer after a thermal reaction process in a thermal reaction chamber of the furnace tube according to a first preset cooling condition to control the temperature of the wafer to drop to a first preset temperature, the first preset cooling condition being used to improve the cooling efficiency of the wafer, and the first preset temperature being used to distinguish the ease with which the wafer is deformed; after the first cooling operation is performed, performing a second cooling operation on the wafer according to a second preset cooling condition to control the temperature of the wafer to drop to a second preset temperature, the second cooling condition being used to limit the deformation of the wafer and prevent the thermal reaction chamber from heating up, the second preset temperature being the preset standby temperature of the thermal reaction chamber; after the second cooling operation is performed, controlling the wafer boat loaded with the wafer to stop rotating according to a preset stop rotation condition, the preset stop rotation condition being used to limit the relative displacement between the wafer and the wafer boat in the furnace tube to reduce the generation of particles.

[0007] Optionally, the first preset cooling condition includes: improving the cooling efficiency of the wafer by controlling the cooling rate of the thermal reaction chamber, the second preset cooling condition includes: limiting the deformation of the wafer by controlling the cooling rate of the thermal reaction chamber, and preventing reheating of the wafer by temperature compensation of the temperature of the thermal reaction chamber, and the preset rotation stop condition includes: preventing relative displacement between the wafer and the wafer boat due to inertia during the rotation stop process by limiting the rotation acceleration of the wafer boat.

[0008] Optionally, the furnace tube includes multiple heating elements and multiple first temperature sensors, the heating elements are used to control the temperature of the thermal reaction chamber to control the temperature of the wafer, wherein the multiple heating elements are respectively installed at different heights outside the thermal reaction chamber, and for each heating element, the installation position of the heating element is mapped to the first temperature sensor installed at the inner wall position of the thermal reaction chamber, so as to collect the temperature in the thermal reaction chamber mapped by the corresponding heating element through the first temperature sensor, wherein the cooling rate of the thermal reaction chamber is controlled by controlling the cooling rate of each heating element to increase the cooling efficiency of the wafer or limit the deformation of the wafer, the cooling rate corresponding to the first cooling operation is greater than the cooling rate corresponding to the second cooling operation, and for each heating element, when the heating element is at the second preset temperature, the temperature collected by the first temperature sensor corresponding to the heating element is temperature compensated according to the corresponding preset temperature compensation value to prevent the thermal reaction chamber from heating up.

[0009] Optionally, the first preset cooling condition includes a first preset time period, a first cooling rate and a first preset interval time period, and the wafer is cooled for the first time in the following manner: each heating element is controlled to maintain a first cooling rate for cooling within the first preset time period, and each heating element is controlled to be at the first preset temperature within the first preset interval time period at the end of the first preset time period. The first cooling rate is used to control the temperature of each heating element to be at the first preset temperature at the end of the first preset time period.

[0010] Optionally, the second preset cooling condition includes a second preset time period, a second cooling rate and a second preset interval time period, and the wafer is cooled for the second time in the following manner: each heating element is controlled to maintain a second cooling rate for cooling within the second preset time period, and at the end of the second preset time period, each heating element is controlled to be at the second preset temperature within the second preset interval time period, and the second cooling rate is used to control the temperature of each heating element to be at the second preset temperature at the end of the second preset time period.

[0011] Optionally, the preset temperature compensation values ​​are increased in descending order according to the installation heights of the heating elements corresponding to the first temperature sensors, and the second preset cooling conditions also include the preset temperature compensation values ​​and preset heating temperatures corresponding to each first temperature sensor. The method also includes: for each heating element, when the heating element is at the second preset temperature, the target temperature is obtained by subtracting the corresponding preset temperature compensation value from the temperature value collected by the first temperature sensor corresponding to the heating element; for each first temperature sensor, when the target temperature corresponding to the first temperature sensor is less than the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to heat up, and when the target temperature corresponding to the first temperature sensor is greater than or equal to the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to stabilize at the second preset temperature.

[0012] Optionally, the preset rotation stop condition includes a preset rotation acceleration and a preset rotation time, and the wafer boat loaded with wafers is controlled to stop rotating in the following manner: the wafer boat is controlled to rotate according to the preset rotation acceleration within the preset rotation time, and the preset rotation acceleration is used to achieve the stop of the rotation of the wafer boat at the end of the preset rotation time.

[0013] Optionally, the method further includes: after the crystal boat stops rotating, controlling the crystal boat to perform a boat-out operation according to preset boat-out conditions, so that the crystal boat moves from the thermal reaction chamber to the loading chamber of the furnace tube, and the preset boat-out conditions are used to reduce the cooling efficiency for the wafers and prevent the thermal reaction chamber from heating up.

[0014] Optionally, the preset boat unloading conditions include a preset boat unloading speed and a preset boat unloading time period, and the boat unloading operation is performed in the following manner: when the crystal boat stops rotating, the closed door between the thermal reaction chamber and the loading chamber is opened, and the crystal boat is controlled to move to the loading chamber at the preset boat unloading speed during the preset boat unloading time period, and the preset boat unloading speed is used to indicate that the boat unloading operation is completed at the end of the preset boat unloading time period, and after the crystal boat stops rotating, when it is determined that the temperature of the heating device is greater than or equal to the second preset temperature, the temperature of each heating element is controlled to be stable at the second preset temperature to prevent the thermal reaction chamber from heating up.

[0015] Optionally, the furnace tube further includes a plurality of second temperature sensors, and for each second temperature sensor, the second temperature sensor is used to collect the temperature of the corresponding heating element. The method further includes: for each second temperature sensor, when the temperature value collected by the second temperature sensor is less than the second preset temperature, controlling the temperature of the heating element corresponding to the second temperature sensor to rise to prevent the thermal reaction chamber from heating up.

[0016] An embodiment of the present application provides a method for reducing particles in a furnace tube, the method comprising: performing a first cooling operation on a wafer after a thermal reaction process in a thermal reaction chamber of the furnace tube according to a first preset cooling condition, so as to control the temperature of the wafer to drop to a first preset temperature, wherein the first preset cooling condition is used to improve the cooling efficiency of the wafer, and the first preset temperature is used to distinguish the ease with which the wafer is deformed; after the first cooling operation is performed, performing a second cooling operation on the wafer according to a second preset cooling condition, so as to control the temperature of the wafer to drop to a second preset temperature, wherein the second cooling condition is used to limit the deformation of the wafer and prevent the thermal reaction chamber from heating up, and the second preset temperature is a preset standby temperature of the thermal reaction chamber; after the second cooling operation is performed, controlling a wafer boat loaded with the wafer to stop rotating according to a preset rotation stop condition, wherein the preset rotation stop condition is used to limit the relative displacement between the wafer and the wafer boat in the furnace tube, so as to reduce the generation of particles. After the thermal reaction process, the wafer is cooled in sections to ensure the cooling efficiency of the wafer in the first cooling process, and to reduce the wafer deformation caused by cooling and prevent the wafer from being reheated in the second cooling process. After the segmented cooling, the wafer boat is controlled to gradually stop rotating to prevent the friction between the wafer and the wafer boat due to inertia during the rotation and the generation of particles, which solves the technical problem of easy generation of particles inside the furnace tube in the prior art, and achieves the technical effect of reducing particles generated by wafer deformation and reducing particles generated by friction between the wafer and the wafer boat.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A flow chart of a method for reducing particles in a furnace tube provided by an embodiment of the present application is shown.

[0020] Figure 2 A schematic diagram of a furnace tube provided in an embodiment of the present application is shown. Figure 1 .

[0021] Figure 3 A schematic diagram of a furnace tube provided in an embodiment of the present application is shown. Figure 2 . DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0023] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0024] In the existing high-temperature furnace process, the wafers are first heated from room temperature to 950°C-1150°C for a thermal reaction. After the thermal reaction, the wafers are cooled from the high temperature environment to room temperature. This dramatic change in temperature increases the thermal stress and deformation of the wafers, causing relative displacement between the wafers and the slots in the wafer boat. Specifically, because the slots in the wafer boat are arranged sequentially from top to bottom, friction between the back of the wafer in the previous slot and the slot creates particles. With the slots in the wafer boat typically spaced 4mm apart, gravity forces particles from the previous slot onto the surface of the wafer in the next slot, forming a collection area near the slots on the wafer boat. Some of these surface particles undergo thermal motion within the thermal reaction chamber, eventually landing on the wafer surface under the influence of airflow and forming an arc-shaped arrangement. This impacts the stability of subsequent wafer processing and, in turn, the yield of finished wafers. The current industry solution is to improve surface particles by optimizing the wafer manufacturing process. However, due to the wide variety of wafer products, the optimization cycle is long and the process is cumbersome. Moreover, product process changes have varying degrees of impact on electrical parameters and yield. The second solution is to replace silicon carbide wafer boats with silicon wafer boats, which have a significant improvement in thermal effects. However, replacing silicon wafer boats in large quantities increases costs, and due to the long life cycle of silicon carbide wafer boats, the replaced wafer boats will be idle, resulting in waste.

[0025] Based on this, the embodiment of the present application provides a method for reducing particles in the furnace tube. After the thermal reaction process, the wafer is cooled in stages to ensure the cooling efficiency of the wafer in the first stage of cooling. In the second stage of cooling, the wafer deformation caused by cooling is reduced and the wafer is prevented from being reheated. After the staged cooling, the wafer boat is controlled to gradually stop rotating, thereby preventing the friction between the wafer and the wafer boat due to inertia during the rotation process and the generation of particles. This solves the technical problem of the easy generation of particles inside the furnace tube in the prior art, and achieves the technical effect of reducing particles generated by wafer deformation and reducing particles generated by friction between the wafer and the wafer boat. The details are as follows:

[0026] See also Figure 1 , Figure 1 This is a flow chart of a method for reducing particles in a furnace tube provided in an embodiment of the present application. Figure 1 As shown, the method for reducing particles in a furnace tube provided by an embodiment of the present application includes the following steps:

[0027] S101: performing a first cooling operation on the wafer after the thermal reaction process in the thermal reaction chamber of the furnace tube according to a first preset cooling condition, so as to control the temperature of the wafer to drop to the first preset temperature.

[0028] See also Figure 2 , Figure 2A schematic diagram of a furnace tube provided in an embodiment of the present application Figure 1 .like Figure 2 As shown, the furnace tube includes a thermal reaction chamber 101, a wafer boat 102, wafers 103, multiple heating elements 104, and multiple first temperature sensors 105. The wafer boat rotates during the thermal reaction process, the first cooling operation, and the second cooling operation. Nitrogen is continuously introduced into the thermal reaction chamber, and at least one wafer is loaded onto the wafer boat. The heating elements are used to control the temperature of the thermal reaction chamber, thereby controlling the temperature of the wafers.

[0029] The multiple heating elements are respectively installed at different heights outside the thermal reaction chamber. For each heating element, the installation position of the heating element is mapped to a first temperature sensor installed at the inner wall position of the thermal reaction chamber, so as to collect the temperature inside the thermal reaction chamber mapped by the corresponding heating element through the first temperature sensor.

[0030] For example, for each heating element, the heating element corresponds to a first temperature sensor, the heating element is arranged outside the thermal reaction chamber, and the first temperature sensor is arranged at the corresponding mapping position of the heating element on the inner wall of the thermal reaction chamber, so that the temperature collected by the first temperature sensor reflects the temperature control situation of the thermal reaction chamber by the corresponding heating element. For each heating element, the heating element corresponds to multiple first temperature sensors, the heating element is arranged outside the thermal reaction chamber, and the multiple first temperature sensors are arranged at the corresponding mapping positions of the heating element on the inner wall of the thermal reaction chamber, so that the temperature control situation of the thermal reaction chamber by the corresponding heating element is determined by other calculation methods such as the average value of the temperatures collected by the multiple first temperature sensors.

[0031] The first preset temperature-lowering condition is used to improve the cooling efficiency of the wafer, and the first preset temperature-lowering condition includes: improving the cooling efficiency of the wafer by controlling the temperature-lowering rate of the thermal reaction chamber.

[0032] The first preset temperature is used to distinguish the ease with which the wafer deforms. That is, when the wafer temperature is greater than or equal to the first preset temperature, particles will not be generated due to deformation, and when the wafer temperature is less than the first preset temperature, particles will be generated due to deformation.

[0033] Furthermore, the first preset cooling condition includes controlling the cooling rate of the thermal reaction chamber by controlling the cooling rate of each heating element to increase the cooling efficiency of the wafer. In other words, since the temperature of the wafer is always greater than or equal to the first preset temperature during the first cooling operation, the cooling efficiency of the wafer can be increased by increasing the cooling rate of each heating element.

[0034] Specifically, the first preset cooling condition includes a first preset time period, a first cooling rate and a first preset interval time period, and the wafer is cooled for the first time in the following manner: each heating element is controlled to maintain a first cooling rate for cooling within the first preset time period, and each heating element is controlled to be at the first preset temperature within the first preset interval time period at the end of the first preset time period. The first cooling rate is used to control the temperature of each heating element to be at the first preset temperature at the end of the first preset time period, and the first preset interval time period is used to stabilize the temperature of the wafer.

[0035] Generally, due to heat exchange, it is considered that the temperature of each heating element is the same as the temperature in the corresponding thermal reaction chamber and the temperature of the wafer.

[0036] For example, the first preset temperature is 900°C. After the wafer undergoes a thermal reaction process in the furnace tube, the temperature in the thermal reaction chamber rises to 1150°C. Therefore, the wafer needs to perform a first cooling operation in the thermal reaction chamber at 1150°C. Therefore, each heating element is controlled to cool to 900°C during the first preset time period. The first preset time period is set to 50 to 84 minutes, the first cooling rate is any rate within the first preset cooling rate range, the first preset cooling rate range is set to 3 to 5°C / min, and the first preset interval time period is set to 10 minutes.

[0037] S102: After the first cooling operation is performed, a second cooling operation is performed on the wafer according to a second preset cooling condition to control the temperature of the wafer to drop to the second preset temperature.

[0038] The second cooling condition is used to limit deformation of the wafer and prevent heating of the thermal reaction chamber. The second preset temperature is a preset standby temperature of the thermal reaction chamber. The second preset cooling condition includes: limiting deformation of the wafer by controlling the cooling rate of the thermal reaction chamber, and preventing reheating of the wafer by temperature compensation of the thermal reaction chamber.

[0039] The cooling rate of the thermal reaction chamber is controlled by controlling the cooling rate of each heating element to limit the deformation of the wafer, and the cooling rate corresponding to the first cooling operation is greater than the cooling rate corresponding to the second cooling operation.

[0040] That is, during the second cooling operation, the wafer temperature is lower than the first preset temperature, and thus, the wafer may deform due to thermal stress, which may easily generate particles. Furthermore, by reducing the cooling rate of each heating element during the second cooling operation, deformation due to thermal stress can be reduced.

[0041] Specifically, the second preset cooling condition includes a second preset time period, a second cooling rate and a second preset interval time period, and the wafer is cooled for the second time in the following manner: each heating element is controlled to maintain a second cooling rate for cooling within the second preset time period, and at the end of the second preset time period, each heating element is controlled to be at the second preset temperature within the second preset interval time period, the second cooling rate is used to control the temperature of each heating element to be at the second preset temperature at the end of the second preset time period, and the second preset interval time period is used to stabilize the temperature of the wafer.

[0042] For example, the second preset temperature is 700°C, so during the second cooling operation, the wafer temperature needs to be cooled from 900°C to 700°C. The second preset time period is set to 134 to 200 minutes, the second cooling rate is any rate within the second preset cooling rate range, the second preset cooling rate range is set to 1 to 1.5°C / min, and the preset interval is set to 10 minutes. In other words, the maximum value of the second preset cooling rate is less than the minimum value of the first preset cooling rate.

[0043] like Figure 2 As shown, multiple first temperature sensors are installed at different heights on the inner wall of the thermal reaction chamber to collect the temperature within the thermal reaction chamber. Furthermore, during the second cooling operation, for each heating element, when the heating element is at the second preset temperature, the temperature collected by the corresponding first temperature sensor is compensated according to the corresponding preset temperature compensation value to prevent the thermal reaction chamber from heating up.

[0044] Because the thermal reaction chamber's preset standby temperature is a second preset temperature, when the temperature measured by the first temperature sensor is lower than the second preset temperature, the heating element corresponding to the first temperature sensor will increase its temperature to prevent the thermal reaction chamber's temperature from falling below the second preset temperature. When the heating element reaches the second preset temperature, the temperature within the thermal reaction chamber will fluctuate due to the wafer boat's rotation. Furthermore, when the wafer boat stops rotating, the temperature within the thermal reaction chamber will also fluctuate. Therefore, to prevent the heating element from heating up again, temperature compensation is used to prevent the heating element from heating up again.

[0045] The preset temperature compensation values ​​increase in descending order based on the installation height of the corresponding heating element. That is, the higher the installation height of the heating element, the smaller the preset temperature compensation value of the corresponding first temperature sensor. Because the bottom wafers leave the thermal reaction chamber first during wafer boat unloading, the cooling temperatures of all wafers are roughly the same as the boat moves downward.

[0046] The second preset cooling condition also includes a preset temperature compensation value and a preset heating temperature corresponding to each first temperature sensor. The method also includes: for each heating element, when the heating element is at the second preset temperature, the target temperature is obtained by subtracting the corresponding preset temperature compensation value from the temperature value collected by the first temperature sensor corresponding to the heating element; for each first temperature sensor, when the target temperature corresponding to the first temperature sensor is less than the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to heat up; when the target temperature corresponding to the first temperature sensor is greater than or equal to the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to stabilize at the second preset temperature.

[0047] That is to say, as long as the heating element reaches the second preset temperature, the target temperature is obtained by subtracting the corresponding preset temperature compensation value from the temperature value collected by the first temperature sensor corresponding to the heating element. Therefore, only when the target temperature is lower than the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to heat up.

[0048] Moreover, during the process of the wafer boat stopping its rotation and the process of the wafer boat being unloaded, the temperature in the thermal reaction chamber gradually decreases. In particular, when the wafer boat is unloaded, the closed door opens, resulting in heat exchange between the loading chamber and the thermal reaction chamber, which again causes the temperature in the thermal reaction chamber to drop. A preset temperature compensation value that changes with height is then set to prevent the thermal reaction chamber from being heated again.

[0049] For each first temperature sensor, the preset heating temperature corresponding to the first temperature sensor is the second preset temperature minus the corresponding preset temperature compensation value.

[0050] For example, if the second preset temperature is 700°C and four first temperature sensors are installed in the thermal reaction chamber, where the preset temperature compensation value corresponding to the first temperature sensor A1 at the highest installation height is 30°C, then the preset heating temperature corresponding to A1 is 670°C, the preset temperature compensation value corresponding to the first temperature sensor A2 at the second highest installation height is 50°C, then the preset heating temperature corresponding to A2 is 650°C, the preset temperature compensation value corresponding to the first temperature sensor A3 at the third highest installation height is 70°C, then the preset heating temperature corresponding to A3 is 630°C, and the preset temperature compensation value corresponding to the first temperature sensor A4 at the lowest installation height is 90°C, then the preset heating temperature corresponding to A4 is 610°C. Furthermore, when the target temperature corresponding to A1 is less than 670°C, the heating element corresponding to A1 is controlled to heat, when the target temperature corresponding to A2 is less than 650°C, the heating element corresponding to A2 is controlled to heat, when the target temperature corresponding to A3 is less than 630°C, the heating element corresponding to A3 is controlled to heat, and when the target temperature corresponding to A4 is less than 610°C, the heating element corresponding to A4 is controlled to heat.

[0051] Exemplarily, the plurality of heating elements correspond to the top, upper middle, lower middle, and bottom regions of the exterior of the thermal reaction chamber, respectively, and furthermore, the first temperature sensors corresponding to the heating elements are correspondingly installed at the top, upper middle, lower middle, and bottom regions of the inner wall of the thermal reaction chamber. The preset temperature compensation value corresponding to the first temperature sensor with the highest installation height is set between 0°C and 70°C, and the preset temperature compensation value corresponding to the compensation value of the first temperature sensor with the lowest installation height is set between 0°C and 200°C. In other words, it is only necessary to ensure that the preset temperature compensation value increases as the installation height decreases, and the preset temperature compensation value can also decrease in sequence according to a proportion or a preset difference, and the preset temperature compensation value corresponding to the first temperature sensor with the highest installation height is set between 0°C and 70°C, and the preset temperature compensation value corresponding to the compensation value of the first temperature sensor with the lowest installation height is set between 0°C and 200°C.

[0052] Among them, the furnace tube also includes a circulating water device, which is installed outside each heating element. The circulating water device is used to cool the wafer. Furthermore, the circulating water device is turned on during the first cooling operation and the second cooling operation to facilitate cooling the wafer.

[0053] S103: After the second temperature reduction operation is performed, the wafer boat loaded with wafers is controlled to stop rotating according to a preset rotation stop condition.

[0054] The preset stop rotation condition is used to limit relative displacement between the wafer and the wafer boat in the furnace tube to reduce particle generation. The preset stop rotation condition includes: limiting the rotational acceleration of the wafer boat to prevent relative displacement between the wafer and the wafer boat due to inertia during the stop rotation process.

[0055] The preset rotation stop condition includes a preset rotation acceleration and a preset rotation time, and the wafer boat loaded with wafers is controlled to stop rotating in the following manner: the wafer boat is controlled to rotate according to the preset rotation acceleration within the preset rotation time, and the preset rotation acceleration is used to achieve the wafer boat stopping rotation at the end of the preset rotation time.

[0056] That is to say, after the second cooling operation, the rotational acceleration of the wafer boat is controlled to smoothly transition the wafer boat from a rotating state to a stationary state, thereby avoiding relative displacement of the wafers placed on the wafer boat slots when the wafer boat stops rotating, thereby reducing the probability of friction between the back of the wafer and the wafer boat slots.

[0057] The method also includes: after the wafer boat stops rotating, controlling the wafer boat to perform a boat unloading operation according to a preset boat unloading condition, so that the wafer boat moves from the thermal reaction chamber to the loading chamber of the furnace tube, and the preset boat unloading condition is used to reduce the cooling efficiency for the wafer and prevent the thermal reaction chamber from heating up.

[0058] The preset boat unloading conditions include: reducing the cooling efficiency of the wafer by limiting the boat unloading speed of the wafer boat, and preventing the thermal reaction chamber from heating up by switching the temperature control for the temperature in the thermal reaction chamber to the temperature control for the heating element.

[0059] The preset boat unloading conditions include a preset boat unloading speed and a preset boat unloading time period, and the boat unloading operation is performed in the following manner: when the wafer boat stops rotating, the closed door between the thermal reaction chamber and the loading chamber is opened, and the wafer boat is controlled to move to the loading chamber at the preset boat unloading speed during the preset boat unloading time period. The preset boat unloading speed is used to indicate that the boat unloading operation is completed at the end of the preset boat unloading time period, and after the wafer boat stops rotating, the temperature of each heating element is controlled to be stable at the second preset temperature to prevent the thermal reaction chamber from heating up.

[0060] like Figure 2As shown, the furnace tube also includes multiple second temperature sensors 106, a closed door 107, and a loading chamber 108. The closed door is used to separate the thermal reaction chamber from the loading chamber. Each second temperature sensor is used to collect the temperature of the corresponding heating element. In other words, after the wafer boat stops rotating, the closed door is opened, thereby controlling the wafer boat to move to the loading chamber at the preset unloading time period and the preset unloading speed to complete the unloading operation.

[0061] While the wafer boat stops rotating, for each second temperature sensor, when the temperature value collected by the second temperature sensor is less than the second preset temperature, the temperature of the heating element corresponding to the second temperature sensor is controlled to rise, so as to prevent the thermal reaction chamber from heating up and stabilize the temperature of the heating element to the second preset temperature.

[0062] In other words, when the wafer boat stops rotating, the temperature sensed by the first temperature sensor and the corresponding preset temperature compensation value is no longer used to determine whether the heating element is heated. Instead, the temperature sensed by the second temperature sensor is used to control whether the heating element is heated. Thus, as long as the temperature sensed by any second temperature sensor is less than the second preset temperature, the temperature of the heating element corresponding to that second temperature sensor is controlled to increase.

[0063] Exemplarily, the preset boat discharge speed is set between 30 and 60 mm / min, so that the preset boat discharge time can be calculated according to the preset boat discharge distance of the furnace tube. Generally, the preset boat discharge time is set between 30 and 60 minutes.

[0064] See also Figure 3 , Figure 3 A schematic diagram of a furnace tube provided in an embodiment of the present application Figure 2 .like Figure 3 As shown, the furnace tube further includes a fan 109 arranged in the loading chamber, and the fan is used to cool the wafers during the boat unloading operation, so as to reduce the temperature of the wafers to room temperature after the wafer boat operation.

[0065] Based on the same application concept, the embodiments of the present application also provide a device for reducing particles in the furnace tube corresponding to the method for reducing particles in the furnace tube provided in the above embodiments. Since the principle of solving the problem by the device in the embodiments of the present application is similar to the method for reducing particles in the furnace tube in the above embodiments of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0066] An embodiment of the present application provides a device for reducing particles in a furnace tube, the device comprising: a first control module, configured to perform a first cooling operation on wafers after a thermal reaction process in a thermal reaction chamber of the furnace tube according to a first preset cooling condition, so as to control the temperature of the wafers to drop to a first preset temperature, wherein the first preset cooling condition is used to improve the cooling efficiency of the wafers, and the first preset temperature is used to distinguish the susceptibility of the wafers to deformation; a second control module, configured to perform a second cooling operation on the wafers according to a second preset cooling condition after the first cooling operation is performed, so as to control the temperature of the wafers to drop to a second preset temperature, wherein the second cooling condition is used to limit deformation of the wafers and prevent heating of the thermal reaction chamber, and the second preset temperature is a preset standby temperature of the thermal reaction chamber; and a third control module, configured to control a wafer boat loaded with the wafers to stop rotating according to a preset rotation stop condition after the second cooling operation is performed, wherein the preset rotation stop condition is used to limit relative displacement between the wafers and the wafer boat in the furnace tube, so as to reduce the generation of particles.

[0067] Based on the same application concept, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for reducing particles in the furnace tube provided in the above embodiment are executed.

[0068] Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc. When the computer program on the storage medium is run, the above-mentioned method of reducing particles in the furnace tube can be executed, by cooling the wafer in sections after the thermal reaction process, so as to ensure the cooling efficiency for the wafer in the first cooling process, reduce the wafer deformation caused by cooling in the second cooling process and prevent the wafer from being reheated, and control the wafer boat to gradually stop rotating after the section cooling, so as to prevent the friction between the wafer and the wafer boat due to inertia during the rotation and generate particles, thereby solving the technical problem of easy generation of particles inside the furnace tube in the prior art, and achieving the technical effect of reducing particles generated by wafer deformation and reducing particles generated by friction between the wafer and the wafer boat.

[0069] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0070] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0071] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0072] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0073] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for reducing particles in a furnace tube, characterized in that: The method comprises: performing a first cooling operation on the wafer after the thermal reaction process in the thermal reaction chamber of the furnace tube according to a first preset cooling condition to control the temperature of the wafer to drop to the first preset temperature. The first preset cooling condition is used to improve the cooling efficiency of the wafer. When the temperature of the wafer is greater than or equal to the first preset temperature, no particles are generated due to deformation. When the temperature of the wafer is less than the first preset temperature, particles are generated due to deformation. After the first cooling operation is performed, a second cooling operation is performed on the wafer according to a second preset cooling condition to control the temperature of the wafer to drop to a second preset temperature, wherein the second preset cooling condition is used to limit deformation of the wafer and prevent the temperature of the thermal reaction chamber from rising, and the second preset temperature is a preset standby temperature of the thermal reaction chamber; After the second temperature reduction operation is performed, the wafer boat loaded with the wafers is controlled to stop rotating according to a preset rotation stop condition, wherein the preset rotation stop condition is used to limit the relative displacement between the wafers and the wafer boat in the furnace tube to reduce the generation of particles; The first preset cooling condition includes: improving the cooling efficiency of the wafer by controlling the cooling rate of the thermal reaction chamber, The second preset cooling condition includes: limiting the deformation of the wafer by controlling the cooling rate of the thermal reaction chamber, and preventing the wafer from being reheated by performing temperature compensation on the temperature of the thermal reaction chamber. The preset rotation stop condition includes: preventing relative displacement between the wafer and the wafer boat due to inertia during the rotation stop process by limiting the rotation acceleration of the wafer boat.

2. The method according to claim 1, characterized in that The furnace tube includes a plurality of heating elements and a plurality of first temperature sensors. The heating elements are used to control the temperature of the thermal reaction chamber to control the temperature of the wafer. The plurality of heating elements are respectively installed at different heights outside the thermal reaction chamber. For each heating element, the installation position of the heating element is mapped to the installation position of a first temperature sensor on the inner wall of the thermal reaction chamber, so as to collect the temperature inside the thermal reaction chamber mapped by the corresponding heating element through the first temperature sensor. The cooling rate of the thermal reaction chamber is controlled by controlling the cooling rate of each heating element to increase the cooling efficiency of the wafer or limit the deformation of the wafer. The cooling rate corresponding to the first cooling operation is greater than the cooling rate corresponding to the second cooling operation. And for each heating element, when the heating element is at the second preset temperature, the temperature collected by the first temperature sensor corresponding to the heating element is temperature compensated according to the corresponding preset temperature compensation value to prevent the thermal reaction chamber from heating up.

3. The method according to claim 2, characterized in that The first preset cooling condition includes a first preset time period, a first cooling rate and a first preset interval time period. The wafer is cooled for the first time by: Control each heating element to maintain a first cooling rate to cool down within a first preset time period, At the end of the first preset time period, each heating element is controlled to be at the first preset temperature within the first preset interval time period, and the first cooling rate is used to control the temperature of each heating element to be at the first preset temperature at the end of the first preset time period.

4. The method according to claim 2, characterized in that The second preset cooling condition includes a second preset time period, a second cooling rate, and a second preset interval time period. The wafer is subjected to a second cooling operation by: Control each heating element to maintain a second cooling rate for cooling within a second preset time period, At the end of the second preset time period, each heating element is controlled to be at the second preset temperature within the second preset interval time period, and the second cooling rate is used to control the temperature of each heating element to be at the second preset temperature at the end of the second preset time period.

5. The method according to claim 4, characterized in that The preset temperature compensation values ​​are arranged in descending order according to the installation height of the heating element corresponding to the first temperature sensor and increase in sequence, the second preset temperature reduction condition also includes the preset temperature compensation value and the preset heating temperature corresponding to each first temperature sensor, and the method further includes: For each heating element, when the heating element is at the second preset temperature, the target temperature is obtained by subtracting the corresponding preset temperature compensation value from the temperature value collected by the first temperature sensor corresponding to the heating element; For each first temperature sensor, when the target temperature corresponding to the first temperature sensor is lower than the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to heat up; when the target temperature corresponding to the first temperature sensor is greater than or equal to the preset heating temperature corresponding to the first temperature sensor, the heating element corresponding to the first temperature sensor is controlled to stabilize at the second preset temperature.

6. The method according to claim 2, characterized in that The preset rotation stop condition includes a preset rotation acceleration and a preset rotation time. The wafer boat loaded with wafers stops rotating by the following methods: The wafer boat is controlled to rotate according to the preset rotation acceleration within the preset rotation time, and the preset rotation acceleration is used to stop the wafer boat from rotating when the preset rotation time ends.

7. The method according to claim 6, characterized in that The method further comprises: After the wafer boat stops rotating, the wafer boat is controlled to perform an unloading operation according to a preset unloading condition, so that the wafer boat moves from the thermal reaction chamber to the loading chamber of the furnace tube. The preset unloading condition is used to reduce the cooling efficiency for the wafer and prevent the thermal reaction chamber from heating up.

8. The method according to claim 7, characterized in that The preset disembarkation conditions include a preset disembarkation speed and a preset disembarkation time period. The boat discharging operation is performed in the following manner: When the wafer boat stops rotating, the closed door between the thermal reaction chamber and the loading chamber is opened, and the wafer boat is controlled to move to the loading chamber at the preset boat-out speed during the preset boat-out time period, wherein the preset boat-out speed is used to indicate that the boat-out operation is completed at the end of the preset boat-out time period, and after the wafer boat stops rotating, the temperature of each heating element is controlled to be stabilized at the second preset temperature to prevent the thermal reaction chamber from heating up.

9. The method according to claim 8, characterized in that The furnace tube further includes a plurality of second temperature sensors, each of which is used to collect the temperature of the corresponding heating element. The method further includes: for each second temperature sensor, when the temperature value collected by the second temperature sensor is less than the second preset temperature, controlling the temperature of the heating element corresponding to the second temperature sensor to increase, so as to prevent the thermal reaction chamber from being heated.

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