Monitoring apparatus and method for a susceptor in a process chamber, epitaxial process apparatus

Abstract

The application relates to the technical field of semiconductor production and manufacturing, and in particular to a monitoring device and method for a susceptor in a process chamber and an epitaxial process equipment. The monitoring device comprises a detection unit comprising at least three dual-wavelength laser sensors for detecting the spatial coordinates of an inner edge laser beam irradiation point in a preheating ring and the spatial coordinates of an outer edge laser beam irradiation point in the susceptor; an adjusting unit arranged on a support structure; a data processing unit for calculating a relative level deviation and a radial gap; and a control unit for controlling the adjusting unit to adjust the height displacement of the susceptor when the relative level deviation is greater than a level deviation threshold value, and for controlling the adjusting unit to adjust the plane displacement of the susceptor when the radial gap exceeds a gap threshold range. The application can realize real-time monitoring and accurate regulation and control of the level and gap of the susceptor in the process chamber under a high-temperature and reduced-pressure environment, and solves the technical problems of a complicated detection and calibration process, low precision and long information lag in the prior art.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a monitoring device and method for a substrate in a process chamber, and an epitaxial process equipment, for monitoring and controlling the levelness of the substrate and the gap between the substrate and the preheating ring. Background Technology

[0002] Epitaxial growth process (EPI) equipment, such as selective vacuum epitaxy (SVA), primarily consists of a chamber, wafer tray / base, preheating ring, bulb heating module, air intake module, vacuum and exhaust system, temperature and pressure monitoring system, and rotation and lifting module. Among these, the gap and leveling of the wafer tray / base are crucial for ensuring process uniformity and repeatability. These two parameters directly affect the uniformity of the gas flow field, temperature field, and reactant concentration within the reaction chamber, ultimately determining the uniformity of the epitaxial layer thickness and material properties.

[0003] Please refer to the reference. Figure 1 and Figure 2 The gap between the preheating ring R1 and the base S1 in the chamber refers to the gap between the inner edge of the preheating ring R1 and the outer edge of the base S1; the leveling of the preheating ring R1 and the base S1 includes the leveling deviation of the preheating ring plane (relative to the horizontal plane), the leveling deviation of the base plane (relative to the horizontal plane), and the relative leveling deviation. The relative leveling deviation is defined as the leveling deviation of the base plane relative to the preheating ring plane.

[0004] Currently, the equipment lacks effective real-time monitoring methods for the gaps and levelness within the process chamber. The graphite tray / base and preheating ring in the process chamber exhibit thermal expansion. During the heating and cooling process, this expansion causes the base to shift, leading to a gradual shift in gaps and levelness. When this shift accumulates to a certain extent, it results in abnormal uniformity of the grown film thickness, thus affecting the product's electrical performance. Currently, monitoring is only possible through inline thickness measurement or offline monitoring, but this only provides a rough indication of gap and levelness drift and has a certain lag, making it difficult to detect problems in a timely manner. Therefore, developing an in-situ, real-time, and precise monitoring and control system is necessary.

[0005] Existing methods for monitoring the gaps and levelness within the chamber require periodically inserting a specific control wafer into the process chamber for epitaxial growth. The condition of the chamber is then reflected by measuring the thickness and uniformity of the grown film, thus achieving the monitoring objective. However, existing technologies suffer from the following main problems: The testing and calibration process is cumbersome: when abnormalities are found in the thickness uniformity, the machine needs to be stopped and the cavity disassembled. In the cold state of the cavity, the degree of deviation of the gap and levelness is measured by a specific tool. The measurement results cannot directly reflect the hot state of the cavity. The position of the support shaft is then manually adjusted based on the cold state measurement data. The calibration process is time-consuming, complicated, lacks automatic closed-loop control, and has poor repeatability.

[0006] Low detection accuracy: The detection process uses a red laser emitter, which has poor measurement accuracy and is easily affected by ambient light noise. Furthermore, it cannot directly measure the levelness of the base. In a depressurized high-temperature epitaxial environment, the thermal radiation intensity of the target surface increases exponentially with temperature. Conventional red lasers suffer severe signal-to-noise ratio degradation due to thermal radiation background noise, making accurate measurement impossible. Moreover, detection is performed in a cold chamber, resulting in errors compared to the hot chamber state, and in-situ real-time detection is not possible, leading to low detection accuracy.

[0007] Long information lag: The equipment is monitored at a low frequency (for example, the thickness of the control sheet is monitored about once every four days), and it is impossible to monitor the changes in the gap and level of the chamber in real time. This will cause abnormal electrical signals of products that are shipped within the lag time. Summary of the Invention

[0008] The technical problem this application aims to solve is that existing monitoring and control schemes for the gap and levelness within chambers have cumbersome testing and calibration processes, low testing accuracy, and long information lag.

[0009] To address the aforementioned technical problems, this application provides a monitoring device for a base in a process chamber. The process chamber includes a preheating ring, a base, and a support structure supporting the base. A gap exists between the inner edge of the preheating ring and the outer edge of the base. The monitoring device includes: The detection unit includes at least three dual-wavelength laser sensors. The laser beams emitted by the dual-wavelength laser sensors cover the inner edge of the preheating ring and the outer edge of the base to detect the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring and the spatial coordinates of the laser beam irradiation point at the outer edge of the base. The spatial coordinates include planar axis coordinates and height axis coordinates. An adjustment unit, disposed on the support structure, is used to adjust the height displacement and planar displacement of the base; The data processing unit is used to calculate the relative levelness deviation and radial clearance. The relative levelness deviation is calculated based on the preheating ring plane equation and the base plane equation. The preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the outer edge of the base. The radial clearance is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle position. The control unit is configured to control the adjustment unit to adjust the height displacement of the base when the relative level deviation is greater than a level deviation threshold, and to control the adjustment unit to adjust the planar displacement of the base when the radial clearance exceeds a clearance threshold range.

[0010] Optionally, the dual-wavelength laser sensor is positioned directly above the inner edge of the preheating ring and the outer edge of the base, or the dual-wavelength laser sensor is positioned obliquely above the inner edge of the preheating ring and the outer edge of the base; the planar coordinates of the laser beam irradiation point are determined based on the installation position of the dual-wavelength laser sensor and the laser beam width.

[0011] Optionally, the detection unit further includes: an image acquisition unit, used to acquire edge image data of the preheating ring and the base; the planar axial coordinates of the laser beam irradiation point are obtained based on the edge image data of the preheating ring and the base; the radius of the inner edge central angle of the preheating ring and the radius of the outer edge central angle of the base are obtained based on the edge image data of the preheating ring and the base.

[0012] Optionally, the detection unit includes four dual-wavelength laser sensors arranged at the same horizontal height, which fit the plane equation using the least squares method; the plane axis includes mutually perpendicular X-axis and Y-axis, and the laser beam irradiation points are the intersections of the inner edge of the preheating ring, the outer edge of the base, and the X-axis and Y-axis, respectively.

[0013] Optionally, the support structure includes a support shaft disposed at the center of the bottom of the base and at least three support arms extending from the support shaft to the bottom edge of the base; the adjustment unit includes a height displacement adjustment rod disposed on the support arm and a planar displacement adjustment rod disposed on the support shaft.

[0014] Optionally, the data processing unit calculates multiple radial gaps; the control unit is also configured to output an alarm signal when the minimum value of the multiple radial gaps is less than a gap warning threshold.

[0015] Optionally, the data processing unit is further configured to calculate the levelness deviation of the preheating ring plane according to the preheating ring plane equation; the control unit is further configured to output an alarm signal when the levelness deviation of the preheating ring plane is greater than the levelness warning threshold.

[0016] Optionally, if no alarm signal is output, the control unit determines whether it is necessary to adjust the height displacement and planar displacement of the base.

[0017] Optionally, the data processing unit is further configured to calculate the variance or standard deviation of multiple radial gaps as gap non-uniformity; the control unit is further configured to control the adjustment unit to adjust the planar displacement of the base when the gap non-uniformity is greater than a non-uniformity threshold.

[0018] Optionally, the height displacement of the base is adjusted according to the relative deflection angle of the plane axis, which is calculated based on the plane equation of the preheating ring and the plane equation of the base.

[0019] Optionally, the planar displacement of the base is adjusted according to the radial clearance.

[0020] Optionally, the data processing unit is also used to perform temperature compensation processing based on the thermal expansion coefficients of the preheating ring and base materials and the temperature of the process chamber.

[0021] Optionally, the laser beam emitted by the dual-wavelength laser sensor includes blue light with a wavelength of 405nm and near-infrared light with a wavelength of 850nm.

[0022] Corresponding to the monitoring device for the base in the aforementioned process chamber, this application also provides a monitoring method for the base in a process chamber, wherein the process chamber includes a preheating ring and a base, and a gap exists between the inner edge of the preheating ring and the outer edge of the base, and the monitoring method includes: At least three dual-wavelength laser sensors are used, and the laser beams emitted by the dual-wavelength laser sensors cover the inner edge of the preheating ring and the outer edge of the base to detect the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring and the spatial coordinates of the laser beam irradiation point at the outer edge of the base; the spatial coordinates include planar axis coordinates and height axis coordinates; Calculate the relative levelness deviation and radial clearance; the relative levelness deviation is calculated based on the preheating ring plane equation and the base plane equation, the preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the outer edge of the base; the radial clearance is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle position; When the relative level deviation is greater than the level deviation threshold, the height displacement of the base is adjusted; when the radial clearance exceeds the clearance threshold range, the planar displacement of the base is adjusted.

[0023] To address the aforementioned technical problems, this application also provides an epitaxial process equipment, including a process chamber and a main control unit, and further including a monitoring device for the base in the aforementioned process chamber.

[0024] Optionally, the data processing unit and the control unit are integrated into the main controller.

[0025] Compared with the prior art, the technical solution of this application has the following beneficial effects: A dual-wavelength laser sensor is used to monitor the outer edge of the base and the inner edge of the preheating ring, obtaining the spatial coordinates of the laser beam irradiation point to fit a plane equation. Based on the fitted plane equation, the relative levelness deviation and radial clearance are calculated, thereby adjusting the height and planar displacement of the base. The dual-wavelength laser sensor can effectively shield the environmental influences caused by ambient light and thermal radiation from objects, thus enabling real-time and accurate monitoring and precise control of the levelness and clearance of the base in the process chamber under high temperature and low pressure conditions.

[0026] An image acquisition unit is used to identify the edge contours of the base and the preheating ring, and to calculate the gap between the base and the preheating ring, effectively avoiding interference from high-temperature gas and particulate dust in the chamber and improving detection accuracy.

[0027] No need to stop the machine to open the cavity, saving downtime for testing and adjustment. It can monitor online in real time under high temperature and low pressure environment, and simultaneously measure multiple parameters such as base level, preheating ring level, relative level and radial clearance. This enables efficient and accurate automatic closed-loop calibration control, avoiding product quality problems caused by clearance and level drift. Attached Figure Description

[0028] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein: Figure 1 This is a schematic diagram of the structure of a process chamber in the prior art; Figure 2 A schematic diagram illustrating the definition of clearance and levelness within the process chamber; Figure 3 This is a schematic diagram of the detection unit and adjustment unit of the monitoring device of the base in an embodiment of this application, located in the process chamber. Figure 4 This is a top view schematic diagram showing the positional relationship between the dual-wavelength laser sensor, the preheating ring, and the base in an embodiment of this application. Figure 5 This is a flowchart illustrating the monitoring method for the base in the process chamber according to an embodiment of this application. Detailed Implementation

[0029] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0030] To address the problems of existing technologies, this application proposes an in-situ monitoring scheme for the base in a process chamber. This scheme can accurately monitor the changes in the level and gap between the base and the preheating ring in real time, and precisely adjust (calibrate) the level of the base and the gap between the base and the preheating ring. It eliminates the need for downtime for opening the chamber, saving downtime for inspection and adjustment, and avoiding product quality problems caused by gap and level drift. The technical solution of this application will be described in detail below with reference to the accompanying drawings and embodiments.

[0031] The monitoring device for the base in the process chamber of this application embodiment includes a detection unit, an adjustment unit, a data processing unit, and a control unit. The process chamber includes a preheating ring, a base, and a support structure supporting the base, with a gap between the inner edge of the preheating ring and the outer edge of the base.

[0032] The detection unit includes at least three dual-wavelength laser sensors. The laser beams emitted by the dual-wavelength laser sensors cover the inner edge of the preheating ring and the outer edge of the base to detect the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring and the spatial coordinates of the laser beam irradiation point at the outer edge of the base. The spatial coordinates include planar axis coordinates and height axis coordinates.

[0033] The adjustment unit is disposed on the support structure and is used to adjust the height displacement and planar displacement of the base.

[0034] The data processing unit is used to calculate the relative level deviation and radial clearance. The relative level deviation is calculated based on the preheating ring plane equation and the base plane equation. The preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the outer edge of the base. The radial clearance is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle.

[0035] The control unit is used to control the adjustment unit to adjust the height displacement of the base when the relative level deviation is greater than the level deviation threshold, and to control the adjustment unit to adjust the planar displacement of the base when the radial clearance exceeds the clearance threshold range.

[0036] The use of a dual-wavelength laser sensor can effectively shield against environmental influences caused by ambient light and thermal radiation from objects. In this embodiment, the laser beam emitted by the dual-wavelength laser sensor includes blue light with a wavelength of 405nm and near-infrared light with a wavelength of 850nm, achieving a detection resolution of 1μm and a levelness detection accuracy of 0.005°. The 405nm blue laser is used as the measurement light for displacement measurement, employing triangulation to measure the height of points on a plane. The 850nm (or 780nm, 940nm) near-infrared laser is used as the reference light or monitoring light to monitor changes in the reflectivity of high-temperature surfaces and detect the intensity of background thermal radiation. Since the high-temperature blackbody radiation from the preheating ring and the graphite material of the base affects measurement accuracy, the background light intensity is estimated using the monitoring light, and then the intensity measured by the measurement light is differentially subtracted, thereby eliminating the influence of the background environment on the measurement.

[0037] Based on the principle that three non-collinear points can define a plane, at least three dual-wavelength laser sensors should be used, and they should be positioned at the same horizontal level. When the number of dual-wavelength laser sensors is greater than or equal to four, the least squares method can be used to fit the plane equation. Please refer to the reference. Figure 3 and Figure 4 The detection unit in this embodiment includes four dual-wavelength laser sensors L1, L2, L3, and L4 positioned at the same horizontal height. The least squares method is used to fit the plane equation. The plane axes include mutually perpendicular X-axis and Y-axis, and the height axis is the Z-axis. The laser beam illumination points are the intersections of the inner edge of the preheating ring R1 and the outer edge of the base S1 with the X-axis and Y-axis, respectively. Specifically, the laser beam illumination point at the inner edge of the preheating ring R1 corresponding to the dual-wavelength laser sensor L1 is the intersection point RL1 of the inner edge of the preheating ring R1 with the positive X-axis, and the laser beam illumination point at the outer edge of the base S1 is the intersection point SL1 of the outer edge of the base S1 with the positive X-axis; the laser beam illumination point at the inner edge of the preheating ring R1 corresponding to the dual-wavelength laser sensor L2 is the intersection point RL2 of the inner edge of the preheating ring R1 with the positive Y-axis, and the laser beam illumination point at the outer edge of the base S1 is the intersection point S1 of the outer edge of the base S1 with the positive Y-axis. L2; The laser beam irradiation point of the inner edge of the preheating ring R1 corresponding to the position of the dual-wavelength laser sensor L3 is the intersection point RL3 of the inner edge of the preheating ring R1 and the negative X-axis, and the laser beam irradiation point of the outer edge of the base S1 is the intersection point SL3 of the outer edge of the base S1 and the negative X-axis; The laser beam irradiation point of the inner edge of the preheating ring R1 corresponding to the position of the dual-wavelength laser sensor L4 is the intersection point RL4 of the inner edge of the preheating ring R1 and the negative Y-axis, and the laser beam irradiation point of the outer edge of the base S1 is the intersection point SL4 of the outer edge of the base S1 and the negative Y-axis.

[0038] Under the high-temperature, depressurized environment of the chamber, the dual-wavelength laser sensor can be activated to scan and detect in real time the heights of four irradiation points on the outer edge of the base S1 and the four irradiation points on the inner edge of the preheating ring R1. To protect the dual-wavelength laser sensor, a quartz heat-insulated window can also be configured, such as... Figure 3 The quartz heat-insulated windows W1 and W3 of the dual-wavelength laser sensors L1 and L3 shown are used to avoid high temperature and contamination of the chamber environment, or even damage to the dual-wavelength laser sensors.

[0039] The laser beam emitted by the dual-wavelength laser sensor covers the inner edge of the preheating ring and the outer edge of the base (including the gap between the inner edge of the preheating ring and the outer edge of the base), such as Figure 3 The laser beams Lb1 and Lb3 emitted by the dual-wavelength laser sensors L1 and L3 shown can be used to detect the height of the laser beam irradiation point on the inner edge of the preheating ring R1 and the height of the laser beam irradiation point on the outer edge of the base S1 at the corresponding positions of the dual-wavelength laser sensors L1 and L3.

[0040] The dual-wavelength laser sensor can be positioned directly above the inner edge of the preheating ring and the outer edge of the base. For example, four dual-wavelength laser sensors can be arranged in a ring and installed on the top of the process chamber (if there is installation space on the top of the process chamber), directly facing the inner edge of the preheating ring and the outer edge of the base. Figure 4 Directly above the X and Y axes shown, in conjunction with the reference. Figure 3 The laser beam is perpendicularly incident on the preheating ring plane and the base plane. Alternatively, the dual-wavelength laser sensor can be positioned diagonally above the inner edge of the preheating ring and the outer edge of the base. For example, four dual-wavelength laser sensors can be arranged in a ring on the sidewall of the process chamber, with the emitted laser beam at a predetermined angle to the preheating ring plane and the base plane to ensure coverage of the inner edge of the preheating ring and the outer edge of the base.

[0041] Please continue to refer to this. Figure 3 In this embodiment, the support structure S2 includes a support shaft S21 located at the center of the base bottom (for supporting the center of the base) and at least three support arms S22 extending from the support shaft S21 to the bottom edge of the base (for supporting the outer edge of the base). The adjustment unit includes a height displacement adjustment rod A12 disposed on the support arms S22 and a planar displacement adjustment rod A11 disposed on the support shaft S21. The number of support arms S22 is at least three, which can stably support the base S1. The support arms S22 are evenly distributed at the bottom of the base S1, and the included angle between adjacent support arms can be equal. The support arms S22 and the height displacement adjustment rod A12 support the bottom of the base S1 near the outer edge. The levelness of the base S1 is adjusted by adjusting the displacement of the height adjustment rod A12 along the height axis (Z-axis). The support shaft S21 and the planar displacement adjusting rod A11 support the bottom center of the base S1. The gap between the base S1 and the preheating ring R1 is adjusted by adjusting the displacement of the planar displacement adjusting rod A11 along the planar axis (X axis and Y axis).

[0042] The data processing unit is used to calculate the relative levelness deviation and radial clearance. In this embodiment, the relative levelness deviation is the levelness deviation of the base plane relative to the preheating ring plane, which can be calculated based on the preheating ring plane equation and the base plane equation. The preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the outer edge of the base. The spatial coordinates include the plane axis (…). Figure 4 X-axis, Y-axis) coordinates and height axis ( Figure 3 The Z-axis coordinate of the laser beam irradiation point is determined based on the height data of the laser beam irradiation point detected by the dual-wavelength laser sensor (e.g., the height distance between the laser beam irradiation point and the dual-wavelength laser sensor, or the height distance between the laser beam irradiation point and the reference horizontal plane).

[0043] by Figure 4 For example, the spatial coordinates of the four laser beam irradiation points on the inner edge of the preheating ring R1 are RL1(x r1 , 0, z r1 ), RL2(0, y r2 , z r2 ), RL3(x r3 , 0, z r3 ), RL4(0, y r4 , z r4 The spatial coordinates of the four laser beam irradiation points on the outer edge of the base S1 are SL1(x). s1 , 0, z s1 ), SL2(0, y s2 , z s2 ), SL3(x s3 , 0, z s3 ), SL4(0, y s4 , z s4 (Where, the Z-axis coordinate z) r1 z r2 z r3 z r4 z s1 z s2 z s3 z s4 The height of the laser beam irradiation point at the inner edge of the preheating ring R1 and the height of the laser beam irradiation point at the outer edge of the base S1, detected by the four dual-wavelength laser sensors L1, L2, L3, and L4, can be determined. X-axis coordinate x r1 x r3 x s1 x s3 and Y-axis coordinates y r2 y r4 y s2 y s4The X and Y coordinates can be determined based on the installation positions of the four dual-wavelength laser sensors L1, L2, L3, and L4 and the laser beam width: If the dual-wavelength laser sensors are positioned directly above the inner edge of the preheating ring and the outer edge of the base (e.g., installed on the top of the process chamber), the X and Y coordinates can be calculated based on the distance between the dual-wavelength laser sensor (or the laser beam center) and the center of the plane, and the laser beam width. If the dual-wavelength laser sensors are positioned diagonally above the inner edge of the preheating ring and the outer edge of the base (e.g., installed on the side wall of the process chamber), the X and Y coordinates can be calculated based on the distance between the dual-wavelength laser sensor (or the laser beam center) and the center of the plane, the laser beam width, and the angle between the laser beam and the plane. The distance between the dual-wavelength laser sensors and the center of the plane can be determined based on the position coordinates of the dual-wavelength laser sensors, specifically the X-axis distance and Y-axis distance from the center of the plane.

[0044] Due to the influence of the cavity environment, if the dual-wavelength laser sensor is installed on the sidewall, the measurement of the X-axis and Y-axis coordinates may be inaccurate. Therefore, the detection unit in this embodiment also includes an image acquisition unit for acquiring edge image data of the preheating ring and the base; the planar axial coordinates of the laser beam irradiation point are obtained based on the edge image data of the preheating ring and the base. The image acquisition unit can employ a camera with a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor, which can accurately acquire edge image data. Figure 3 As shown, the image acquisition unit (e.g., a CCD camera) C1 can be positioned above the base S1, for example, mounted on the top of the process chamber. The CCD camera's imaging range should cover the base S1 and the preheating ring R1 (e.g., Figure 3 The dashed area in the image is used to identify the edge contours of the base S1 and the preheating ring R1, effectively avoiding interference from high-temperature gases and particulate dust, and improving detection accuracy. The preheating ring R1 is typically installed in a fixed position within the process chamber. Under high-temperature conditions, due to thermal expansion, a gap exists between the inner edge of the preheating ring R1 and the outer edge of the base S1. The inner edge of the preheating ring R1 and the outer edge of the base S1 will shift towards this gap, but the outer edge of the preheating ring R1 remains fixed. Therefore, the CCD camera can identify the edge contours and gaps of the base S1 and the preheating ring R1 using the outer edge (outer diameter) of the preheating ring as a reference. By calculating the distance between the inner and outer edges of the preheating ring R1 and the distance between the outer edge of the base S1 and the outer edge of the preheating ring R1, edge image data of the preheating ring and the base can be obtained. Furthermore, the X-axis and Y-axis coordinates of the four laser beam irradiation points on the inner edge of the preheating ring R1 and the outer edge of the base S1 can be calculated.

[0045] Based on the spatial coordinates of the four laser beam irradiation points on the inner edge of the preheating ring, the plane equation of the preheating ring is obtained by least squares fitting as follows: z r = a r x + b r y + c r .

[0046] Based on the spatial coordinates of the four laser beam illumination points on the outer edge of the base, the plane equation of the base is obtained by least squares fitting and expressed as: z s = a s x + b s y + c s .

[0047] Relative levelness deviation θ rel According to θ rel = arctan calculate.

[0048] The radial clearance ΔGap(Φ) is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle, expressed as: ΔGap(Φ) = R r (Φ) - R s (Φ), where Φ is the central angle, R r (Φ) is the radius at the central angle Φ of the inner edge of the preheating ring, R s (Φ) is the radius at the central angle Φ of the outer edge of the base, and ΔGap(Φ) is the radial clearance at the central angle Φ.

[0049] by Figure 4 For example, the central angle Φ at the position corresponding to sensor L1 is 0°, and ΔGap(0°) = x r1 - x s1 The central angle Φ at the location corresponding to sensor L2 is 90°, and ΔGap(90°) = y. r2 - y s2 The central angle Φ at the location corresponding to sensor L3 is 180°, and ΔGap(180°) = x r3 - x s3 The central angle Φ at the location corresponding to sensor L4 is 270°, and ΔGap(270°) = y. r4 - y s4 .

[0050] In practical applications, it is necessary to calculate the radial clearances ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ) at multiple central angle positions. nThis allows for a comprehensive assessment of whether the gap between the preheating ring and the base has shifted and affected the process. The radius of the inner edge central corner of the preheating ring and the outer edge central corner of the base can be obtained from the edge image data of the preheating ring and the base. The image acquisition unit can accurately detect the edge image data of the preheating ring and the base (such as the X-axis and Y-axis coordinates of the edge point at the central corner Φ, or the distance from the edge point at the central corner Φ to the center, i.e., the radius). This allows for the determination of the radius of the inner edge of the preheating ring and the outer edge of the base at any central corner position. The radial gap can be calculated at predetermined angles, for example, ΔGap(0°), ΔGap(10°), ΔGap(20°), ..., ΔGap(350°).

[0051] The control unit is used to determine whether it is necessary to adjust the height displacement and planar displacement of the base to control the adjustment unit to adjust the base. Specifically: when the relative levelness deviation θ rel Greater than the levelness deviation threshold θ set2 The adjustment unit is then controlled to adjust the height displacement of the base, and is used to adjust the radial clearance when it exceeds the clearance threshold range ΔG. min ~ΔG max The adjustment unit is then controlled to adjust the planar displacement of the base. The horizontal deviation threshold θ is set according to the actual application and process requirements. set2 and gap threshold range ΔG min ~ΔG max When the relative levelness deviation θ rel Greater than the levelness deviation threshold θ set2 Explain the relative levelness deviation θ rel Excessive deviation will affect the process, requiring adjustment of the base's levelness, i.e., adjusting the height displacement of the base, to reduce the relative levelness deviation θ. rel When the radial clearance ΔGap(Φ) exceeds the clearance threshold range ΔG min ~ΔG max This indicates that the radial clearance ΔGap(Φ) is too small (ΔGap(Φ) < ΔG). min Or ΔGap(Φ) is too large (ΔGap(Φ)>ΔG max This will affect the process, requiring adjustment of the gap between the base and the preheating ring, i.e., adjustment of the planar displacement of the base, so that the radial gap ΔGap(Φ) is within the gap threshold range ΔG. min ~ΔG max Within this range, multiple radial gaps ΔGap(Φ) should all be within the gap threshold range ΔG. min ~ΔG max Within or as close as possible to the gap threshold range ΔG min ~ΔG max When θ rel = θset2 The level can be adjusted or left unadjusted; when ΔGap(Φ) = ΔG min Or ΔGap(Φ) = ΔG max The gap can be adjusted or left unadjusted.

[0052] In practice, the height displacement of the base can be adjusted according to the relative deflection angle of the planar axis. This relative deflection angle is calculated based on the preheating ring plane equation and the base plane equation. The relative deflection angle of the planar axis includes the X-axis relative deflection angle θ. x The relative angle θ with respect to the Y-axis y X-axis relative deflection angle θ x The angular deviation of the base plane X-axis relative to the preheating ring plane X-axis is determined by θ. x =arctan(Δa), Δa = a s -a r Calculate the relative deflection angle θ along the Y-axis. y The angular deviation of the base plane Y-axis relative to the preheating ring plane Y-axis is determined by θ. y = arctan(Δb), Δb = b s -b r Calculation. With Figure 3 Taking the height displacement adjustment rod A12 of the adjustment unit shown as an example, the control unit adjusts according to the relative deflection angle θ of the X-axis. x Y-axis relative deflection angle θ y The height displacement component of each height displacement adjusting rod A12 is calculated based on its position, and each height displacement adjusting rod A12 is controlled to rise (along the positive Z-axis) or fall (along the negative Z-axis) according to its respective height displacement component, thereby adjusting the levelness of the base S1. In other embodiments, one or more height displacement adjusting rods A12 can also be controlled to move (fine-tuning) by a small predetermined Z-axis displacement.

[0053] The planar displacement of the base is adjusted according to the radial clearance. Figure 3 Taking the planar displacement adjusting rod A11 of the adjustment unit as an example, the control unit calculates the X-axis and Y-axis displacement of the planar displacement adjusting rod A11 based on the radial gap exceeding the gap threshold range, and controls the planar displacement adjusting rod A11 to move along the positive or negative X-axis and Y-axis, thereby adjusting the gap between the base S1 and the preheating ring R1. In other embodiments, the planar displacement adjusting rod A11 can also be controlled to move by a smaller predetermined X-axis and Y-axis displacement (fine-tuning).

[0054] Furthermore, the data processing unit can also be used to calculate multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ4). nThe variance or standard deviation of the variance is used as the gap non-uniformity σ. gap The control unit can also be used when the gap non-uniformity σ gap Greater than the non-uniformity threshold σ set The adjustment unit is then controlled to adjust the planar displacement of the base. The non-uniformity threshold σ is set according to the actual application and process requirements. set When the gap non-uniformity σ gap Greater than the non-uniformity threshold σ set Explain the gap non-uniformity σ gap An excessively large gap (resulting in poor uniformity of the gap between the base and the preheating ring) will affect the process. Therefore, it is necessary to adjust the gap between the base and the preheating ring, i.e., adjust the planar displacement of the base, to reduce the gap non-uniformity σ. gap When σ gap = σ set The gap can be adjusted or left unadjusted.

[0055] The control unit can precisely drive and control the movement of the height displacement adjustment rod and the plane displacement adjustment rod, with an adjustment accuracy of ±1μm, thereby achieving precise calibration of levelness and gap.

[0056] Typically, leveling should be performed first, until the relative leveling deviation meets the standard (θ). rel ≤θ set2 Then adjust the gap, because adjusting the gap first may cause the base to collide with the preheating ring, and subsequent leveling adjustments may also cause the gap to change.

[0057] After base calibration (leveling adjustment or gap adjustment), the relative leveling deviation θ needs to be re-detected and recalculated. rel Radial clearance ΔGap(Φ), clearance non-uniformity σ gap Then determine whether leveling or gap adjustment is needed.

[0058] In this embodiment, to prevent collisions between the base and the preheating ring during adjustment, a gap warning threshold Gap is set according to the actual application and process requirements. set The control unit is also used to handle multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ4). n The minimum value of Gap min Less than the gap warning threshold Gap set An alarm signal will be output, requiring the machine to be stopped and the cavity disassembled to investigate the cause of the insufficient gap. min = Gap set You can choose to call the police or not.

[0059] Furthermore, since the preheating ring is fixedly installed inside the process chamber, the relative horizontal deviation θ rel The preheating ring plane is used as a reference, but due to thermal expansion, the inner edge of the preheating ring will also shift, causing the preheating ring plane to shift relative to the horizontal plane. When the shift is too large, the relative levelness deviation θ is used as the reference. rel Determining whether level adjustment is needed (using the preheating ring plane as a reference) would be inaccurate. Therefore, in this embodiment, a level warning threshold θ is also set according to actual application and process requirements. set1 The data processing unit is also used to calculate the levelness deviation θ of the preheating ring plane based on the preheating ring plane equation. r The control unit is also configured to detect level deviation θ of the preheating ring plane. r Greater than the level warning threshold θ set1 An alarm signal will be output, requiring the machine to be stopped and the cavity disassembled to investigate the cause of the excessive level deviation of the preheating ring plane and to calibrate the preheating ring plane. When θ r = θ set1 It can either trigger an alarm or not. The levelness deviation of the preheating ring plane relative to the horizontal plane is called the levelness deviation θ of the preheating ring plane. r According to θ r = arctan calculate.

[0060] If the control unit does not output an alarm signal, it determines whether the height and planar displacement of the base need to be adjusted. If adjustment is required, it controls the adjustment unit to adjust the base. In other words, the control unit first determines the adjustment based on the minimum radial clearance value, Gap. min The horizontal deviation θ of the preheating ring plane r Determine if an alarm is needed, then assess and adjust the levelness and gap (refer to...). Figure 5 In other embodiments, if the collision of the base or the displacement of the preheating ring plane during adjustment is not considered, the gap warning threshold may not be set. set or levelness warning threshold θ set1 .

[0061] Considering the thermal expansion effect of the preheating ring and base materials under high-temperature conditions, the data processing unit is also used to perform temperature compensation processing based on the thermal expansion coefficients of the preheating ring and base materials and the temperature of the process chamber. The data processing unit reads the chamber temperature T of the equipment temperature control system in real time. s The temperature compensation process includes processing according to the temperature compensation model H. ture =H raw - α*(T s -T refTemperature compensation correction is performed, where α is the coefficient of thermal expansion of the preheating ring and base material, and T s T represents the real-time temperature of the chamber. ref The reference temperature for the chamber (set according to actual process requirements), H raw The original value (the value before temperature compensation correction), H ture This is the correction value (the value after temperature compensation correction).

[0062] In this embodiment, the original values ​​are the detection values ​​of the detection unit, including: the spatial coordinates of the laser beam irradiation point, the radius of the central angle of the inner edge of the preheating ring, and the radius of the central angle of the outer edge of the base. The data processing unit first performs temperature compensation correction on the detection values ​​according to the temperature compensation model, and then fits the preheating ring plane equation and the base plane equation according to the correction values ​​to calculate the relative levelness deviation θ. rel Radial clearance ΔGap(Φ), horizontal deviation θ of the preheating ring plane r Gap non-uniformity σ gap X-axis relative deflection angle θ x The relative angle θ with respect to the Y-axis y And output it to the control unit.

[0063] In other embodiments, the original value can also be a calculated value, and the data processing unit calculates the relative levelness deviation θ based on the detection values ​​of the detection unit (the spatial coordinates of the laser beam irradiation point, the radius of the central angle of the inner edge of the preheating ring, and the radius of the central angle of the outer edge of the base). rel Radial clearance ΔGap(Φ), horizontal deviation θ of the preheating ring plane r Gap non-uniformity σ gap X-axis relative deflection angle θ x The relative angle θ with respect to the Y-axis y Then, the calculated values ​​are corrected for temperature compensation according to the temperature compensation model, and the corrected value, i.e., the corrected relative levelness deviation θ, is then used. rel Radial clearance ΔGap(Φ), horizontal deviation θ of the preheating ring plane r Gap non-uniformity σ gap X-axis relative deflection angle θ x The relative angle θ with respect to the Y-axis y The output is sent to the control unit.

[0064] Corresponding to the monitoring device for the base described above, the monitoring method for the base in the process chamber of this application embodiment includes: employing at least three dual-wavelength laser sensors, wherein the laser beams emitted by the dual-wavelength laser sensors cover the inner edge of the preheating ring and the outer edge of the base, to detect the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring and the spatial coordinates of the laser beam irradiation point at the outer edge of the base; calculating the relative level deviation and radial clearance; adjusting the height displacement of the base when the relative level deviation is greater than the level deviation threshold; and adjusting the planar displacement of the base when the radial clearance exceeds the clearance threshold range.

[0065] The relative level deviation is calculated based on the preheating ring plane equation and the base plane equation. The preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the outer edge of the base. The spatial coordinates include plane axis coordinates and height axis coordinates. The radial gap is the radius difference between the inner edge of the preheating ring and the outer edge of the base at the same central angle position.

[0066] The dual-wavelength laser sensor is positioned directly above the inner edge of the preheating ring and the outer edge of the base, or it is positioned diagonally above the inner edge of the preheating ring and the outer edge of the base; the planar coordinates of the laser beam irradiation point are determined based on the installation position of the dual-wavelength laser sensor and the width of the laser beam.

[0067] The monitoring method for the base in the process chamber may further include: acquiring edge image data of the preheating ring and the base using an image acquisition unit; obtaining the planar axis coordinates of the laser beam irradiation point based on the edge image data of the preheating ring and the base; and obtaining the radius of the central angle of the inner edge of the preheating ring and the radius of the central angle of the outer edge of the base based on the edge image data of the preheating ring and the base.

[0068] The number of dual-wavelength laser sensors is four, which are set at the same horizontal height; the least squares method is used to fit the plane equation; the plane axis includes the mutually perpendicular X-axis and Y-axis, and the laser beam irradiation points are the intersections of the inner edge of the preheating ring, the outer edge of the base, and the X-axis and Y-axis, respectively.

[0069] The height displacement of the base is adjusted by a height displacement adjustment rod located at the bottom edge of the base; the planar displacement of the base is adjusted by a planar displacement adjustment rod located at the center of the bottom of the base.

[0070] The monitoring method for the base in the process chamber may further include: outputting an alarm signal when the minimum value of multiple radial gaps is less than the gap warning threshold.

[0071] The monitoring method for the base in the process chamber may further include: calculating the levelness deviation of the preheating ring plane according to the preheating ring plane equation; and outputting an alarm signal when the levelness deviation of the preheating ring plane is greater than the levelness warning threshold.

[0072] If no alarm signal is output, it is determined whether the height and planar displacement of the base need to be adjusted. Specifically, the height displacement of the base is adjusted based on the relative level deviation; if the relative level deviation is greater than the level deviation threshold, the height displacement of the base is adjusted. The planar displacement of the base is adjusted based on the radial clearance; if the radial clearance exceeds the clearance threshold range, the planar displacement of the base is adjusted.

[0073] The monitoring method for the base in the process chamber may further include: calculating the variance or standard deviation of multiple radial gaps as gap non-uniformity; and controlling the adjustment unit to adjust the planar displacement of the base when the gap non-uniformity is greater than the non-uniformity threshold.

[0074] The height displacement of the base is adjusted according to the relative deflection angle of the planar axis, which is calculated based on the plane equation of the preheating ring and the plane equation of the base. The planar displacement of the base is adjusted according to the radial clearance.

[0075] The monitoring method for the base in the process chamber may further include: performing temperature compensation processing based on the thermal expansion coefficients of the preheating ring and the base material and the temperature of the process chamber.

[0076] For specific implementation, please refer to Figure 5 : Step S11: Calculate the radial clearance ΔGap(Φ) and the levelness deviation θ of the preheating ring plane. r Radial clearance ΔGap(Φ) = R r (Φ) - R s (Φ), calculate multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ) n ); the levelness deviation θ of the preheating ring plane r = arctan .

[0077] Step S12: Determine if the radial clearance is at its minimum value, Gap. min ≥Gap set If yes, proceed to step S13; otherwise, proceed to step S14. min Multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ n The minimum value in ) Gap set This is the gap warning threshold.

[0078] Step S13, determine whether θ r ≤θ set1 If yes, proceed to step S15; otherwise, proceed to step S14. If Gap min ≥Gap set Then determine the horizontal deviation θ of the preheating ring plane. r Is ≤θ set1 θ set1 This is the level warning threshold.

[0079] Step S14: Output an alarm signal. min <Gap set Or θ r >θ set1 An alarm has been triggered, requiring the machine to be shut down and the cavity disassembled for inspection.

[0080] Step S15, calculate the relative levelness deviation θ rel Continue to step S16. Relative levelness deviation θ rel =arctan .

[0081] Step S16, determine whether θ rel >θ set2 If yes, proceed to step S17; otherwise, proceed to step S18. set2 This is the threshold for levelness deviation.

[0082] Step S17, leveling adjustment. If θ rel >θ set2 The levelness of the base needs to be adjusted, which can be done based on the relative deflection angle θ along the X-axis. x The relative angle θ with respect to the Y-axis y Adjust the height displacement of the base, θ x = arctan(Δa), Δa = a s -a r θ y = arctan(Δb), Δb = b s -b r After adjusting the levelness, recalculate θ. rel The process involves judgment and adjustment, specifically steps S15, S16, and S17, until θ is reached. rel ≤θ set2 .

[0083] Step S18: Calculate the radial clearance ΔGap(Φ) and the clearance non-uniformity σ. gap Continue to step S19. Calculate multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ4). n), non-uniformity σ gap Multiple radial gaps ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ n The variance or standard deviation of ).

[0084] Step S19, determine whether ΔG min <ΔGap(Φ)≤ΔG max And σ gap <σ set If yes, proceed to step S21; otherwise, proceed to step S20. It is necessary to determine each radial gap ΔGap(Φ1), ΔGap(Φ2), ΔGap(Φ3), ..., ΔGap(Φ4). n Are they all within the gap threshold range ΔG? min ~ΔG max Inside, σ set This is the non-uniformity threshold.

[0085] Step S20, gap adjustment. If ≤ΔG min or >ΔG max radial clearance or σ gap ≥σ set The gap between the base and the preheating ring needs to be adjusted, which can be based on ≤ΔG. min or >ΔG max The radial clearance adjusts the planar displacement of the base.

[0086] Step S21, chamber operation. If ΔG min <ΔGap(Φ)≤ΔG max And σ gap <σ set To ensure the normal operation of the chamber, continue the next real-time monitoring and control.

[0087] This application also provides an epitaxial process equipment, including a process chamber, a main control unit, and a monitoring device for a base in the process chamber.

[0088] The data processing unit and control unit can be integrated into the main controller. Alternatively, the data processing unit and control unit can be separate chips installed in the process chamber, or they can be integrated into the same chip and installed in the process chamber.

[0089] Those skilled in the art will understand that, after reading this application, the foregoing content is presented by way of example only and is not intended to be restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are all within the spirit and scope of the exemplary embodiments of this application.

Claims

1. A monitoring device for a base in a process chamber, the process chamber comprising a preheating ring, a base, and a support structure supporting the base, wherein a gap exists between the inner edge of the preheating ring and the outer edge of the base, characterized in that, include: The detection unit includes at least three dual-wavelength laser sensors. The laser beams emitted by the dual-wavelength laser sensors cover the inner edge of the preheating ring and the outer edge of the base to detect the spatial coordinates of the laser beam irradiation point on the inner edge of the preheating ring and the spatial coordinates of the laser beam irradiation point on the outer edge of the base. The spatial coordinates include planar axis coordinates and height axis coordinates. The detection unit also includes an image acquisition unit for acquiring edge image data of the preheating ring and the base. The planar axis coordinates of the laser beam irradiation point are obtained based on the edge image data of the preheating ring and the base. The radii of the central angle positions of the inner edge of the preheating ring and the outer edge of the base are also obtained based on the edge image data of the preheating ring and the base. An adjustment unit, disposed on the support structure, is used to adjust the height displacement and planar displacement of the base; The data processing unit is used to calculate the relative levelness deviation and radial clearance. The relative levelness deviation is calculated based on the preheating ring plane equation and the base plane equation. The preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point on the outer edge of the base. The radial clearance is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle position. The control unit is configured to control the adjustment unit to adjust the height displacement of the base when the relative level deviation is greater than the level deviation threshold, and to control the adjustment unit to adjust the planar displacement of the base when the radial clearance exceeds the clearance threshold range.

2. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The dual-wavelength laser sensor is positioned directly above or diagonally above the inner edge of the preheating ring and the outer edge of the base.

3. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The detection unit includes four dual-wavelength laser sensors set at the same horizontal height, and uses the least squares method to fit the plane equation; the plane axis includes mutually perpendicular X-axis and Y-axis, and the laser beam irradiation points are the intersection points of the inner edge of the preheating ring, the outer edge of the base, and the X-axis and Y-axis, respectively.

4. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The support structure includes a support shaft located at the center of the base bottom and at least three support arms extending from the support shaft to the bottom edge of the base; the adjustment unit includes a height displacement adjustment rod located on the support arms and a planar displacement adjustment rod located on the support shaft.

5. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The data processing unit calculates multiple radial gaps; the control unit is also used to output an alarm signal when the minimum value of the multiple radial gaps is less than the gap warning threshold.

6. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The data processing unit is also used to calculate the levelness deviation of the preheating ring plane according to the preheating ring plane equation; the control unit is also used to output an alarm signal when the levelness deviation of the preheating ring plane is greater than the levelness warning threshold.

7. The monitoring device for the base in the process chamber as described in claim 5 or 6, characterized in that, If no alarm signal is output, the control unit determines whether the height displacement and planar displacement of the base need to be adjusted.

8. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The data processing unit is also used to calculate the variance or standard deviation of multiple radial gaps as gap non-uniformity; the control unit is also used to control the adjustment unit to adjust the planar displacement of the base when the gap non-uniformity is greater than the non-uniformity threshold.

9. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The height displacement of the base is adjusted according to the relative deflection angle of the plane axis, which is calculated based on the plane equation of the preheating ring and the plane equation of the base.

10. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The planar displacement of the base is adjusted according to the radial clearance.

11. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The data processing unit is also used to perform temperature compensation processing based on the thermal expansion coefficients of the preheating ring and base materials and the temperature of the process chamber.

12. The monitoring device for the base in the process chamber as described in claim 1, characterized in that, The laser beam emitted by the dual-wavelength laser sensor includes blue light with a wavelength of 405nm and near-infrared light with a wavelength of 850nm.

13. A method for monitoring a base in a process chamber, the process chamber comprising a preheating ring and a base, wherein a gap exists between the inner edge of the preheating ring and the outer edge of the base, characterized in that, include: At least three dual-wavelength laser sensors are employed, with the laser beams emitted by these sensors covering the inner edge of the preheating ring and the outer edge of the base, to detect the spatial coordinates of the laser beam irradiation points on the inner and outer edges of the preheating ring and base. The spatial coordinates include planar axis coordinates and height axis coordinates. An image acquisition unit is used to acquire edge image data of the preheating ring and base. The planar axis coordinates of the laser beam irradiation points are obtained based on the edge image data of the preheating ring and base. The radii of the central angle positions on the inner and outer edges of the preheating ring and base are also obtained based on the edge image data of the preheating ring and base. Calculate the relative levelness deviation and radial clearance; the relative levelness deviation is calculated based on the preheating ring plane equation and the base plane equation, the preheating ring plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the inner edge of the preheating ring, and the base plane equation is obtained by fitting the spatial coordinates of the laser beam irradiation point at the outer edge of the base; the radial clearance is the difference in radius between the inner edge of the preheating ring and the outer edge of the base at the same central angle position; When the relative level deviation is greater than the level deviation threshold, the height displacement of the base is adjusted; when the radial clearance exceeds the clearance threshold range, the planar displacement of the base is adjusted.

14. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The dual-wavelength laser sensor is positioned directly above or diagonally above the inner edge of the preheating ring and the outer edge of the base.

15. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The number of dual-wavelength laser sensors is four, which are set at the same horizontal height; the least squares method is used to fit the plane equation; the plane axis includes the mutually perpendicular X-axis and Y-axis, and the laser beam irradiation points are the intersections of the inner edge of the preheating ring, the outer edge of the base, and the X-axis and Y-axis, respectively.

16. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The height displacement of the base is adjusted by a height displacement adjustment rod located at the bottom edge of the base; the planar displacement of the base is adjusted by a planar displacement adjustment rod located at the center of the bottom of the base.

17. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, Also includes: An alarm signal is output when the minimum value of multiple radial gaps is less than the gap warning threshold.

18. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, Also includes: The levelness deviation of the preheating ring plane is calculated based on the preheating ring plane equation; when the levelness deviation of the preheating ring plane is greater than the levelness warning threshold, an alarm signal is output.

19. The method for monitoring the base in the process chamber as described in claim 17 or 18, characterized in that, If no alarm signal is output, determine whether the height displacement and planar displacement of the base need to be adjusted.

20. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, Also includes: The variance or standard deviation of multiple radial gaps is calculated as the gap non-uniformity; when the gap non-uniformity is greater than the non-uniformity threshold, the planar displacement of the base is adjusted.

21. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The height displacement of the base is adjusted according to the relative deflection angle of the plane axis, which is calculated based on the plane equation of the preheating ring and the plane equation of the base.

22. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The planar displacement of the base is adjusted according to the radial clearance.

23. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, Also includes: Temperature compensation is performed based on the thermal expansion coefficients of the preheating ring and base materials, as well as the temperature of the process chamber.

24. The monitoring method for the base in the process chamber as described in claim 13, characterized in that, The laser beam emitted by the dual-wavelength laser sensor includes blue light with a wavelength of 405nm and near-infrared light with a wavelength of 850nm.

25. An epitaxial process apparatus, comprising a process chamber and a main control unit, characterized in that, It also includes a monitoring device for the base in the process chamber as described in any one of claims 1 to 12.

26. The epitaxial process equipment as described in claim 25, characterized in that, The data processing unit and the control unit are integrated into the main control computer.

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