Method and system for detecting rotational speed

Abstract

The application belongs to the technical field of semiconductor manufacturing, and provides a rotating speed detection method and a detection system. The method comprises the following steps: providing a semiconductor device and an optical detection device; acquiring simulation track information of a model surface of a self-rotating seat under different theoretical rotating speed ratios and different entering self-rotating seat angle; establishing a standard pulse column diagram according to the simulation track information, so as to obtain a theoretical corresponding relationship between a theoretical column peak number, a theoretical column peak width, a theoretical rotating speed ratio and an entering self-rotating seat angle; obtaining actual measurement detection data through the optical detection device; obtaining an actual measurement pulse column diagram according to the actual measurement detection data; and obtaining a self-rotating speed of the self-rotating seat according to the actual measurement pulse column diagram, the theoretical corresponding relationship and the rotating speed of the orbiting seat. The method establishes a theoretical corresponding relationship, does not depend on a driving pulse trigger signal of the orbiting seat, does not need to modify the structure of the device, realizes the detection of the self-rotating speed of the self-rotating seat, and is suitable for the self-rotating seat speed measurement of various types of semiconductor devices.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a rotational speed detection method and detection system. Background Technology

[0002] In the manufacturing process of semiconductors and integrated circuits, specialized equipment is typically used to execute various processes. This semiconductor equipment is not only diverse and complex in structure, but also requires precise monitoring of its operating status to ensure stable operation. Taking semiconductor growth equipment as an example, it includes a spinner and a orbiter. The orbiter has a orbital groove to support it, and a flow channel is located on the bottom of the orbital groove. By providing driving gas to the flow channel, an air cushion is formed under the spinner, raising it and causing it to rotate. This facilitates uniform mixing of the growth source material near the substrate surface and improves temperature uniformity in the vicinity of the substrate surface, thereby enhancing the quality and uniformity of the film formation.

[0003] In semiconductor growth equipment, the uniformity of gas mixing and temperature difference in the region above the substrate is directly affected by the combined influence of the revolution of the orbiting head and the rotation of the spinner, thus affecting the film quality on the substrate surface. Therefore, during semiconductor growth, it is necessary to accurately monitor and control the motion states of the orbiting head and spinner to ensure film quality. However, since the spinner relies on the driving gas to rotate during the thin film growth process on the substrate surface, its motion state is affected by many factors such as revolution, pressure, gas flow field distribution, and temperature field distribution. This makes it difficult to detect the motion state of the spinner, increasing the uncertainty of spinner motion control and hindering good film quality on the substrate surface.

[0004] To monitor the rotation status of a spinner, existing technologies generally employ two methods. The first method uses a trigger pulse signal from a rotary drive to calculate the spinner's rotational speed. This method relies heavily on the trigger pulse signal, and delays in the trigger pulse signal can lead to inaccurate speed measurements. The second method involves structural modifications to the existing semiconductor device's orbiter, spinner, and chamber. For example, this involves adding detection through-holes to the bottom of the chamber and orbiter, and setting detection marks, such as groove patterns, on the bottom surface of the spinner. The spinner's rotational speed is determined based on the periodic changes in these detection marks. However, this method complicates the semiconductor device's structure, increases production costs, and is unsuitable for semiconductor devices without structural modifications.

[0005] Therefore, a new speed detection method is urgently needed to solve the above-mentioned problems in the existing technology. Summary of the Invention

[0006] The purpose of this application is to provide a rotation speed detection method and system that does not rely on the drive pulse trigger signal of the oscillator and does not require structural modification of the equipment. It can measure the rotation speed of the oscillator during the operation of semiconductor equipment and is applicable to the rotation speed measurement of various types of semiconductor equipment.

[0007] To achieve the above objectives, the rotational speed detection method provided in this application includes at least the following steps:

[0008] S1: Provide a semiconductor device and an optical detection apparatus, wherein the semiconductor device includes a spin seat for supporting a substrate, a orbital seat for supporting the spin seat, a rotation device for driving the orbital seat to revolve, and a gas channel disposed on the orbital seat and used to drive the spin seat to rotate; the optical detection apparatus is used to emit a detection beam to obtain detection data of a substrate area and an outer area on the surface of the orbital seat, wherein there is a difference between the detection data of the substrate area and the outer area to generate a pulse histogram;

[0009] S2: Obtain the simulated trajectory information of the model surface corresponding to the rotator under different theoretical speed ratios and different entry angles of the rotator, wherein the theoretical speed ratio is the ratio of the rotation speed of the rotator to the rotation speed of the orbital seat;

[0010] S3: Establish a standard pulse histogram based on the simulated trajectory information to obtain the theoretical correspondence between the theoretical number of peaks, the theoretical peak width, the theoretical rotational speed ratio, and the angle of entry into the spindle.

[0011] S4: Place the substrate on the rotating seat, control the rotating device to drive the orbital seat to revolve, provide driving gas to the gas channel to drive the rotating seat to rotate, and obtain measured detection data of the substrate area and the area outside the substrate through the optical detection device;

[0012] S5: Obtain a measured pulse histogram based on the measured detection data;

[0013] S6: The rotation speed of the self-rotating seat is obtained based on the measured pulse histogram, the theoretical correspondence, and the rotational speed of the orbital seat in step S4.

[0014] Optionally, the measured detection data includes any one of reflectivity data, temperature data, or distance measurement data, and the standard pulse histogram and the measured pulse histogram show a periodic variation trend.

[0015] Optionally, in step S2, center O is defined as the center of the model corresponding to the spinner, a radial line with center O of the model corresponding to the spinner as the starting point is used as the reference line, the starting intersection point of the simulated detection point corresponding to the detection beam and the edge of the model corresponding to the spinner is O1, and the angle between the line connecting O and O1 and the reference line is the angle of entering the spinner.

[0016] Optionally, the step of obtaining the simulated trajectory information includes:

[0017] Establish a substrate rotation model for the semiconductor device;

[0018] Based on the substrate rotation model, the simulated trajectory information is obtained using a template matching mathematical modeling method.

[0019] Optionally, the substrate rotation model includes a substrate model, a self-rotating model, and a revolution-oriented model. Step S2, the step of obtaining the simulated trajectory information using a template-matching mathematical modeling method, includes:

[0020] S21: Provide and control the detection simulation point to enter the substrate area on the surface of the orbital seat model from a set position, and keep the relative position of the detection simulation point in the substrate rotation model unchanged;

[0021] S22: Control the self-rotating model and the orbiting model to rotate at a set theoretical speed ratio;

[0022] S23: Obtain the simulated trajectory curve formed by the simulated detection point on the self-rotating model;

[0023] S24: Change the value of the theoretical speed ratio and / or the position of the detection simulation point entering the substrate area of ​​the orbital model surface, and repeat the above steps to obtain the simulation trajectory curves under different theoretical speed ratios and different entry angles of the orbital model.

[0024] Optionally, the orbital model carries M circumferentially arranged spinner models, denoted as the 1st to the Mth spinner models, where M is a positive integer greater than 1. Step S23, the step of obtaining the simulated trajectory curve, includes:

[0025] S231: During the j-th revolution period of the i-th rotational model, obtain the coordinate set of the detection simulation point on the i-th rotational model to obtain the corresponding simulation trajectory curve that changes with time; where i is a positive integer not exceeding M, j is a positive integer not exceeding K, and K is a preset number of periods.

[0026] S232: Perform coordinate transformation on the simulated trajectory curve on the i-th rotating seat model to obtain the simulated trajectory curve of the detection simulation point on each of the rotating seat models during the j-th revolution period.

[0027] Optionally, after step S232 is completed, the following steps are also performed:

[0028] S233: Iterate through the values ​​of j and repeat steps S231 to S232 to obtain the simulated trajectory curves of the detection simulation point on each of the self-rotating models during the first to the Kth revolution periods.

[0029] Optionally, the steps for creating a standard pulse histogram include:

[0030] The simulated detection values ​​corresponding to the substrate area on the surface of the self-rotating model in the simulated trajectory curve are set as first standard logic values, and the simulated detection values ​​corresponding to the outer substrate area on the self-rotating model are set as second standard logic values ​​lower than the first standard logic values, so as to generate the standard bar chart.

[0031] Optionally, the measured detection data is reflectivity data, the number of substrates carried on the spinner is at least 2, there is a substrate spacing between two adjacent substrates on the same spinner, at least one bar peak in the measured pulse histogram has inflection point data, after step S4 is completed, the substrate spacing and the spot diameter of the detection beam are obtained, and it is determined that the spot diameter is greater than the substrate spacing. Step S5 also includes data processing of the measured pulse histogram.

[0032] Optionally, the measured detection data is temperature data, the number of substrates carried on the rotating seat is at least 2, and there is a substrate spacing between two adjacent substrates on the same rotating seat. After step S4 is completed, the measured pulse histogram is differentiated to obtain a differentiated pulse histogram with peak values ​​all greater than 0. When at least one peak of the differentiated pulse histogram has inflection point data, the substrate spacing and the spot diameter of the detection beam are obtained, and it is determined that the spot diameter is greater than the substrate spacing. Step S5 also includes data processing of the measured pulse histogram.

[0033] Optionally, in step S5, the step of performing data processing on the measured pulse histogram includes:

[0034] The validity of the inflection point data is determined to decide whether to assign the inflection point data as the peak value of the columnar peak region or to assign the inflection point data as the bottom value of the columnar peak region to divide the columnar peak region into peaks.

[0035] Optionally, if there is an extreme value difference between the peak value and the trough value in the columnar peak region where the inflection point data is located, the step of performing a validity judgment on the inflection point data includes:

[0036] If the difference between the peak value and the inflection point data does not exceed 10% of the extreme value difference, then the inflection point data is assigned the peak value.

[0037] If the difference between the peak value and the inflection point data is greater than 10% of the extreme value difference, then the inflection point data is assigned the peak bottom value.

[0038] Optionally, the measured pulse histogram includes a group of pulse peaks corresponding to each of the rotating seats under one revolution period, and the group of pulse peaks includes at least one peak. In step S6, the step of obtaining the rotation speed of the rotating seat based on the measured pulse histogram, the theoretical correspondence, and the rotational speed of the revolution seat in step S4 includes:

[0039] S61: Obtain the number of columnar peaks in the pulse columnar peak group corresponding to the self-rotating seat, and the columnar peak width data group composed of the widths of each columnar peak;

[0040] S62: Based on the number of columnar peaks in the theoretical correspondence, obtain at least one theoretical speed ratio corresponding to the same number of columnar peaks, and a theoretical columnar peak width data group corresponding to each theoretical speed ratio;

[0041] S63: Compare the differences between the column peak width data group and each of the theoretical column peak width data groups, and select the theoretical speed ratio corresponding to the theoretical column peak width data group with the smallest difference as the target speed ratio;

[0042] S64: The rotational speed of the oscillator is obtained based on the target rotational speed ratio and the rotational speed of the orbital seat in step S4.

[0043] This application also provides a detection system for performing any of the speed detection methods described above, the detection system comprising:

[0044] An optical inspection device is used to emit a detection beam to scan the substrate area and the area outside the substrate on the surface of the orbital mount of a semiconductor device. The detection data obtained by the optical inspection device from scanning the substrate area and the detection data obtained from scanning the area outside the substrate have differences to generate a pulse histogram.

[0045] The communication is connected to the main control device of the optical detection device, which has pre-stored the theoretical correspondence between the number of theoretical peaks and the theoretical peak width of each standard pulse histogram under different theoretical rotation speed ratios and different entry angles of the spindle.

[0046] Compared with existing technologies, the rotational speed detection method and system provided in this application have at least the following advantages:

[0047] Considering that the motion trajectory of the detection beam in the substrate region and the outer region of the optical detection device is related to the rotational speed of the spindle, the rotational speed of the orbital seat, and the angle at which the detection beam enters the spindle, and that there are differences between the detection data acquired by the optical detection device in the substrate region and the outer region to generate a pulse histogram, by using simulated trajectory information under different theoretical speed ratios and different entry angles of the spindle, and the corresponding standard pulse histogram, the theoretical peak number, theoretical peak width, theoretical speed ratio, and theoretical entry angle of the spindle are obtained. This provides theoretical reference data for detecting the motion state of the spindle. The whole process is simple and fast, requires no structural modification of the semiconductor equipment, saves production costs, and eliminates the dependence on the drive pulse trigger signal detection of the semiconductor equipment, avoiding the influence of signal delay and improving the stability and reliability of the entire detection process. The detection system provided in this application is used to execute the above-mentioned speed detection method, and therefore also has the above-mentioned beneficial effects. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 The diagram shown is a flowchart of a speed detection method provided in this application.

[0050] Figure 2 The diagram shown is a schematic diagram of the semiconductor equipment and detection system in a speed detection method provided in this application.

[0051] Figure 3 The diagram shown is a top view of the orbital seat in a speed detection method provided in this application.

[0052] Figure 4 The diagram shown is a schematic diagram of the gas channel on the surface of the orbital seat in a rotation speed detection method provided in this application.

[0053] Figure 5 The diagram shown is a flowchart illustrating the process of obtaining simulated trajectory information using mathematical modeling in a speed detection method provided in this application.

[0054] Figure 6 The diagram shown is a flowchart illustrating the process of obtaining a simulated trajectory curve in a speed detection method provided in this application.

[0055] Figure 7 The diagram shown is a structural schematic of the simulated trajectory curves of the rotator surface at different theoretical speed ratios in a speed detection method provided in this application.

[0056] Figure 8 The diagram shows a flowchart illustrating the process of obtaining the rotational speed of a self-rotating seat based on a measured pulse histogram, theoretical correspondence, and the rotational speed of the orbital seat in a rotational speed detection method provided in this application.

[0057] Figure 9 The image shown is a measured pulse histogram of reflectivity within one revolution cycle in a rotational speed detection method provided in this application.

[0058] Figure 10 The diagram shown is a structural schematic of the simulated trajectory curve on the surface of a self-rotating model in a rotation speed detection method provided in this application.

[0059] Figure 11 Displayed as Figure 10 The standard pulse histogram corresponding to the simulated trajectory curve shown.

[0060] Illustration of reference numerals in the attached diagram:

[0061] 11. Rotating seat; 12. Revolutionary seat; 121. Gas channel; 13. Substrate; 21. Optical inspection device; 22. Main control device; 31. Baseline; 32. Simulated trajectory curve. Detailed Implementation

[0062] To make the technical objectives, technical solutions, and technical effects of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0063] Therefore, the following detailed description of embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] In the description of this application, it should be noted that the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an implementation or example, which are included in at least one implementation or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more implementations or examples.

[0065] This invention provides a rotation speed detection method for real-time monitoring of the motion state of a self-rotating component in a semiconductor device. (Refer to...) Figure 1 The rotational speed detection method includes steps S1 to S6, specifically including:

[0066] S1: Provides a semiconductor device and an optical inspection device 21. The semiconductor device includes a spin seat 11 for supporting a substrate, a revolving seat 12 for supporting the spin seat 11, a rotating device for driving the revolving seat 12 to revolve, and a gas channel 121 disposed on the revolving seat 12 and used to drive the spin seat 11 to rotate. The optical inspection device 21 is used to emit a detection beam to obtain detection data of the substrate area and the area outside the substrate on the surface of the revolving seat 12. There is a difference between the detection data of the substrate area and the area outside the substrate to generate a pulse histogram.

[0067] S2: Obtain the simulated trajectory information of the model surface corresponding to the spinner 11 under different theoretical speed ratios and different entry angles of the spinner. The theoretical speed ratio is the ratio of the spin speed of the spinner 11 to the speed of the revolution seat 12.

[0068] S3: Establish a standard pulse histogram based on the simulated trajectory information to obtain the theoretical correspondence between the theoretical number of peaks, theoretical peak width, theoretical speed ratio, and entry angle of the spindle.

[0069] S4: Place the substrate 13 on the rotating seat 11, control the rotation device to drive the revolution seat 12 to revolve, provide driving gas to the gas channel 121 to drive the rotating seat 11 to rotate, and obtain the measured detection data of the substrate area and the area outside the substrate through the optical detection device 21.

[0070] S5: Obtain the measured pulse histogram based on the measured detection data;

[0071] S6: The rotational speed of the self-rotating seat is obtained based on the measured pulse bar graph and the rotational speed of the orbital seat according to the theoretical correspondence.

[0072] In the rotational speed detection method of this embodiment, simulated trajectory information under different theoretical rotational speed ratios and different entry angles of the spinner is obtained, and corresponding standard pulse histograms are plotted. Each motion state of the substrate rotation model has a specific standard pulse histogram, thereby establishing a theoretical correspondence between the number and width of theoretical peaks in the standard pulse histogram and the theoretical rotational speed ratio and entry angle of the spinner. This ensures that each specific theoretical rotational speed ratio and entry angle of the spinner have a uniquely corresponding number and width of theoretical peaks, providing sufficient theoretical reference data for subsequent detection of the spinner's motion state and guaranteeing the ability to detect the spinner's motion state. Furthermore, by adjusting the theoretical rotational speed ratio and entry angle of the spinner, this method eliminates the need to detect the rotational speed of the spinner and the revolution seat one by one. This significantly reduces the amount of data computation during the acquisition of simulated trajectory information while ensuring the subsequent detection of the spinner's motion state, effectively improving work efficiency.

[0073] Therefore, by using the rotation speed detection method of the present invention, the rotation speed of the self-rotating seat 11 can be detected. Moreover, this method does not require structural modification of the semiconductor equipment, thus saving production costs. At the same time, it eliminates the dependence on the accuracy of the drive pulse trigger signal detection of the semiconductor equipment, avoids the influence of signal delay, and improves the stability of the entire detection process and the reliability of the detection results. This makes the method applicable to the rotation speed detection of self-rotating seats of various types of semiconductor equipment.

[0074] In step S1, refer to Figure 2 and Figure 3 The semiconductor device includes a spin seat 11 and a revolving seat 12. The spin seat 11 is located on the revolving seat 12, and one or more spin seats 11 can be arranged on the revolving seat 12. Each spin seat 11 holds one or more substrates 13. When the semiconductor device is working, the revolving seat 12 and the spin seat 11 rotate, causing the spin seat 11 to rotate on the revolving seat 12 and revolve around the rotation axis of the revolving seat 12, thereby driving the substrate 13 to rotate.

[0075] In an optional embodiment, the semiconductor device can be configured to perform a preset process on the substrate 13. The preset process can be, for example, an epitaxial film growth process or other suitable processes. The semiconductor device can be a semiconductor growth device, such as a CVD (Chemical Vapor Deposition) device, or other suitable types of semiconductor devices. The semiconductor device has a process chamber as the place for performing the preset process. The spinner 11 and the orbiter 12 are both located in the process chamber.

[0076] In an optional embodiment, refer to Figure 3 and Figure 4The upper surface of the orbital seat 12 is provided with several orbital grooves, and the bottom surface of the orbital grooves is provided with gas channels 121. The rotating seat 11 is placed in the orbital grooves. By providing driving gas to the gas channels 121 on the bottom surface of the orbital grooves, an air cushion can be formed under the rotating seat 11, thereby raising the rotating seat 11 and causing it to rotate. At the same time, the rotating device can drive the orbital seat 12 to revolve, thereby causing the rotating seat 11 to revolve around the rotation axis of the orbital seat 12. When a preset process is performed on the substrate 13, such as a thin film growth process on the surface of the substrate 13, the rotating seat 11 rotates and revolves simultaneously. This facilitates the uniform mixing of the growth source material in the process chamber near the surface of the substrate 13 and helps maintain the uniformity of temperature difference in the area near the surface of the substrate 13, thereby improving the film quality on the surface of the substrate 13.

[0077] In step S1, the optical detection device 21 emits a detection beam to scan the substrate area and the area outside the substrate on the surface of the orbiter 12. The detection beam intersects with the surfaces of the substrate 13, the spinner 11 and the orbiter 12 to form several detection points, thereby obtaining the measured detection data at each detection point.

[0078] The optical detection device 21 can be, for example, a reflectance measuring device, an optical temperature measuring device, an optical distance measuring device, or other suitable measuring devices, each of which is implemented using conventional techniques in the art. The detection beam can be, for example, light within a specific wavelength range, and the detection data can include, for example, one or more of temperature data, reflectance data, distance data, and other suitable types of data.

[0079] During the scanning of the surface of the orbiter 12 using the detection beam, there are differences between the detection data obtained from scanning the substrate area of ​​the orbiter 12 surface and the detection data obtained from scanning the area outside the orbiter 12 surface. "Difference" can be understood as a logical difference between the detection data obtained from scanning the substrate area and the detection data obtained from scanning the area outside the substrate. For example, the reflectivity of each detection point in the substrate area is significantly higher than that of each detection point in the area outside the substrate. For example, the temperature of each detection point in the substrate area is significantly lower than that of each detection point in the area outside the substrate. For example, the distance between each detection point in the substrate area is significantly smaller than that between each detection point in the area outside the substrate.

[0080] It should be noted that the above examples are only for the convenience of understanding the solution of this application and are not intended to limit the scope of protection of this application. The physical quantity detected by the optical detection device 21 can also be other physical quantities that satisfy the above differences.

[0081] Step S2, the step of obtaining simulated trajectory information, includes: establishing a substrate rotation model of the semiconductor device; and obtaining simulated trajectory information based on the substrate rotation model using a template matching mathematical modeling method. The specific implementation of the template matching data modeling method is a conventional technical approach.

[0082] Specifically, the established substrate rotation model has structural dimensions that are proportional to or scaled down from the semiconductor device. It includes a substrate model scaled down to or scaled down from the substrate, a spinner model scaled down to or scaled down from the spinner, and a orbiter model scaled down to or scaled down from the orbiter. The substrate model, spinner model, and orbiter model in the substrate rotation model correspond one-to-one with the substrate 13, spinner 11, and orbiter 12 in the semiconductor device, respectively. One or more spinner models can be set on the orbiter model, and one or more substrate models can be set on the spinner model. The spinner model can rotate and revolve with the orbiter model.

[0083] In this embodiment, the model corresponding to the self-rotating seat 11 is the self-rotating seat model, referring to... Figure 3 Center O is defined as the center of the spinner model. Any radial line originating from center O is used as the baseline. The intersection of the simulated detection point corresponding to the detection beam and the starting point of the spinner model's edge is defined as O1. The angle between the line connecting O and O1 and the baseline is the entry angle into the spinner. The simulated detection point can be understood as the detection point of the detection beam, simulated beam, or virtual beam on the surfaces of the spinner and revolution models, used to simulate the detection point of the detection beam on the surface of revolution 12.

[0084] In an optional embodiment, the simulated trajectory information includes a simulated trajectory curve, with reference to... Figure 5 In step S2, the mathematical modeling method using template matching is used to obtain simulated trajectory information, including steps S21 to S24, as detailed below.

[0085] S21: Provides and controls the detection simulation point to enter the substrate area on the surface of the orbital seat model from a set position, and keeps the relative position of the detection simulation point in the substrate rotation model unchanged. Specifically, by controlling the position of the detection simulation point entering the substrate area on the surface of the orbital seat model, it is possible to simulate the detection beam entering the substrate area on the surface of the orbital seat 12 at a set entry angle. Furthermore, during this detection process, the relative position of the detection simulation point in the overall space of the substrate rotation model remains constant, so that the relative position of the detection simulation point on the surface of the orbital seat model changes with the revolution and rotation of the orbital seat model.

[0086] S22: Control the rotation of the self-rotating model and the revolution model to rotate at the set theoretical speed ratio.

[0087] S23: Obtain the simulated trajectory curve formed by the detection simulation point on the self-rotating model. As the orbital model and the self-rotating model continue to rotate, since the relative position of the detection simulation point in the space where the substrate rotation model is located remains unchanged, the detection simulation point forms a simulated trajectory curve on the surface of the self-rotating model.

[0088] S24: Change the value of the theoretical speed ratio and / or the position of the detection simulation point entering the substrate area on the surface of the orbital seat model, and repeat the above steps to obtain the simulated trajectory curves under different theoretical speed ratios and different entry angles of the orbital seat. By controlling the detection simulation point to enter the substrate area on the surface of the orbital seat model at various set positions, the detection beam is simulated to enter the substrate area at different entry angles of the orbital seat. The orbital seat model and the orbital seat model are controlled to rotate at various set theoretical speed ratios to simulate the orbital seat and the orbital seat rotating at different theoretical speed ratios, thereby obtaining the simulated trajectory information of the detection beam on the surface of the orbital seat 11 under various motion states.

[0089] In an optional embodiment, the orbital model carries M self-rotating models, which are arranged sequentially along the circumference of the orbital model. These M self-rotating models are denoted as the 1st to the Mth self-rotating models, where M is a positive integer greater than 1. (Refer to...) Figure 6 In step S23, obtaining the simulated trajectory curve includes steps S231 to S232, as detailed below.

[0090] S231: During the j-th revolution cycle of the i-th spinner model, obtain the set of coordinates of the detection simulation point on the i-th spinner model to obtain the corresponding simulation trajectory curve that changes with time; where i is a positive integer not exceeding M, j is a positive integer not exceeding K, and K is the preset number of cycles. The value of parameter K can be set according to actual needs, and the value of M corresponds to the number of spinners 11 on the revolution seat 12 in the semiconductor device.

[0091] S232: Perform coordinate transformation on the simulated trajectory curve on the i-th rotating seat model to obtain the simulated trajectory curve of the detected simulation point on its respective rotating seat model during the j-th revolution period. Since the difference in rotation state and position between different rotating seats 11 placed on the same rotating seat 12 is theoretically only in the angle, the simulated trajectory graphics on other rotating seat models can be obtained by coordinate transformation to reduce the amount of data computation and improve the efficiency of data modeling and simulation.

[0092] Furthermore, referring to the same Figure 6After step S232 is completed, step S233 is also included: iterating through the values ​​of j and repeating steps S231 to S232 to obtain the simulated trajectory curves of the detected simulation points on their respective rotating models during the 1st to Kth revolution cycles. Through steps S231 to S233, the currently set theoretical speed ratio and the simulated trajectory curves formed by the detected simulation points on their respective rotating models after K revolution cycles at the entry angle of the rotating base can be obtained.

[0093] Reference Figure 7 , Figure 7 The diagram shows the simulated trajectory curves formed by the detection beam on the surface of the self-rotating model when the rotational speed of the orbital model is 1 rpm and the rotational speeds ω of the self-rotating model are 0 rpm, 1 rpm, 2 rpm, 3 rpm to 17 rpm. Figure 7 The x and y axes in the figure represent dimensional information in mm. Since several substrate models are placed on the surface of the spinner model, the simulated trajectory curve is distributed across the surface of the spinner model, with some parts located on the surfaces of the substrate models. Simulation verification shows that each set theoretical rotational speed ratio and entry angle into the spinner corresponds to a unique simulated trajectory curve.

[0094] In step S3, the step of establishing a standard pulse histogram based on the simulated trajectory information includes: setting each simulated detection value corresponding to the substrate area on the surface of the self-rotating model in the simulated trajectory curve as a first standard logic value, and setting each simulated detection value corresponding to the outer substrate area on the self-rotating model as a second standard logic value, so as to generate a standard pulse histogram; wherein, the vertical axis of the standard histogram is used to represent the simulated detection value of each detection simulation point, the horizontal axis is the simulation time, and the second standard logic value is lower than the first standard logic value, and the standard pulse histogram shows a periodic change trend with time.

[0095] The standard pulse histogram includes theoretical pulse peak groups corresponding to each rotor model under any revolution period. Each theoretical pulse peak group includes at least one theoretical peak. For any given theoretical speed ratio and entry angle to the rotor, there are several theoretical pulse peak groups under different revolution periods. The step S3 to obtain the theoretical correspondence includes: obtaining the number and width of theoretical peaks corresponding to each theoretical pulse peak group; establishing a mapping relationship between the number and width of theoretical peaks and the corresponding theoretical speed ratio and entry angle to the rotor; wherein, the widths of several theoretical peaks in the theoretical pulse peak group form a theoretical peak width data group.

[0096] In step S4, the substrate 13 is placed on the rotating seat 11, and the rotating device drives the orbital seat 12 to revolve. Driving gas is supplied to the gas channel to drive the rotating seat 11 to rotate. An optical detection device 21 emits a detection beam onto the substrate area on the surface of the orbital seat 12 while maintaining the position of the optical detection device 21 unchanged. The optical detection device 21 acquires detection data in real time as the measured detection data. Next, step S5 is executed to obtain a measured pulse histogram based on the measured detection data.

[0097] In step S5, by using time as the horizontal axis and the measured data of each detection point as the vertical axis, a measured pulse histogram that shows a periodic trend over time can be formed, and the measured pulse histogram has several column peaks.

[0098] In an optional embodiment, the measured detection data is reflectivity data, the number of substrates carried on the spinner 11 is at least 2, there is a substrate spacing between two adjacent substrates on the same spinner 11, the pulse histogram has several columnar peaks, of which at least one columnar peak has inflection point data, after obtaining the measured detection data by executing step S4, the method further includes: obtaining the substrate spacing and the spot diameter of the detection beam; furthermore, when the spot diameter is greater than the substrate spacing, the method further includes: performing data processing on the measured pulse histogram.

[0099] In an optional embodiment, the measured detection data is temperature data, the number of substrates carried on the spinner 11 is at least 2, and there is a substrate spacing between two adjacent substrates on the same spinner 11. After obtaining the measured detection data by executing step S4, the method further includes: performing derivative processing on the measured pulse histogram to obtain a derivative pulse histogram, which has several column peaks; when at least one column peak of the derivative pulse histogram has inflection point data, obtaining the substrate spacing and the spot diameter of the detection beam, and determining that the spot diameter is greater than the substrate spacing, step S5 further includes: performing data processing on the measured pulse histogram.

[0100] The steps for differentiating the measured pulse histogram include: differentiating the measured pulse histogram and calculating its absolute value to obtain a differentiated pulse histogram where all peak values ​​are greater than 0.

[0101] In this embodiment, the step of performing data processing on the measured pulse histogram includes: determining the validity of the inflection point data to determine whether to assign the inflection point data to the peak value of the corresponding histogram peak region, or to assign the inflection point data to the bottom value of the corresponding histogram peak region to perform peak segmentation on the corresponding histogram peak region.

[0102] Specifically, when the measured data is reflectance data, the inflection point data is the reflectance data corresponding to the inflection point in the measured pulse histogram; when the measured data is temperature data, the inflection point data is the temperature data corresponding to the inflection point in the derivative pulse histogram of the measured pulse histogram.

[0103] In an optional embodiment, there is an extreme value difference between the peak value and the bottom value in the columnar peak region where the inflection point data is located. The step of determining the validity of the inflection point data includes: if the difference between the peak value and the inflection point data does not exceed a preset percentage of the extreme value difference, the inflection point data is assigned as the peak value; if the difference between the peak value and the inflection point data is greater than a preset percentage of the extreme value difference, the inflection point data is assigned as the bottom value. The preset percentage can be 8%, 10%, 12%, or other suitable values, and the specific value can be set according to actual needs.

[0104] This invention discovers that when the distance between two adjacent substrates 13 on the spinner 11 is large, the rotation speed of the spinner 11 can be obtained with high accuracy by using the measured pulse histogram, theoretical correspondence, and the rotational speed of the orbiter 12. However, when the distance between the substrates is small, making the spot diameter larger than the substrate spacing, the obtained pulse histogram is prone to inflection point spikes, which leads to a greater risk of distortion in the subsequent obtained rotation speed of the spinner 11. By judging the validity of the inflection point data, it is possible to determine whether it is necessary to split the peak region of the histogram where the inflection point data is located, which helps to improve the accuracy of detecting the rotation speed of the spinner 11.

[0105] Furthermore, due to the complex environment of the process chamber in semiconductor equipment, which has a significant impact on temperature, temperature data exhibits more spikes compared to reflectivity data, and the pulse square wave characteristics are less significant. In this case, directly using the inflection points in the measured pulse histogram may lead to the inability to achieve effective temperature control. That is, it is impossible to control the temperature uniformity in every area within the process chamber. Based on the requirement of temperature control in this field: stability within a certain temperature difference fluctuation range, where the temperature fluctuation range can be set according to process requirements, the trend of the differentiated pulse histogram obtained after differentiating the measured pulse histogram can be used as the temperature change trend. The point of abrupt change in the trend can be regarded as an inflection point.

[0106] In this embodiment, the measured pulse histogram includes the pulse histogram peak group corresponding to each transpose 11 under any revolution period. The pulse histogram peak group includes at least one histogram peak. In step S6, referring to... Figure 8 The steps of obtaining the rotation speed of the self-rotating seat 11 based on the measured pulse histogram, the theoretical correspondence, and the rotation speed of the orbiting seat 12 in step S4 include steps S61 to S65, as detailed below.

[0107] S61: Obtain the number of columnar peaks in the pulse columnar peak group corresponding to a self-rotating seat 11, and the columnar peak width data group composed of the widths of each columnar peak; specifically, count the number of columnar peaks in the corresponding pulse columnar peak group as the number of columnar peaks; obtain the width of each columnar peak in the corresponding pulse columnar peak group and record it as the columnar peak width, so as to form the columnar peak width data group.

[0108] S62: Based on the theoretical correspondence of the number of columnar peaks, obtain at least one theoretical speed ratio corresponding to the same number of columnar peaks, and a set of theoretical columnar peak width data corresponding to each theoretical speed ratio; specifically, obtain at least one theoretical speed ratio corresponding to the number of theoretical columnar peaks that is consistent with the number of columnar peaks in the theoretical correspondence, wherein at least one set of theoretical columnar peak width data corresponds to the same theoretical speed ratio, and then obtain the corresponding set of theoretical columnar peak width data based on the obtained theoretical speed ratios.

[0109] S63: Compare the differences between the column peak width data set and each theoretical column peak width data set, and select the theoretical speed ratio corresponding to the theoretical column peak width data set with the smallest difference as the target speed ratio. Specifically, calculate the difference between the average column peak width and each theoretical column peak width, and select the theoretical speed ratio corresponding to the theoretical column peak width with the smallest adiabatic value as the target speed ratio.

[0110] S64: Obtain the rotation speed of the self-rotating seat based on the target speed ratio and the rotation speed of the orbital seat in step S4; wherein, the rotation speed of the orbital seat can be obtained from the control parameters of the rotating device.

[0111] In this embodiment of the rotational speed detection method, corresponding to the rotational speed ratio of the semiconductor device and the angle at which the detection beam enters the spinner, the theoretical rotational speed ratio and the position of the detection simulation point entering the substrate area on the surface of the orbital model are used as variables to obtain all possible trajectory patterns on the surface of the spinner 11 to form simulated trajectory information. The entire calculation process does not require individual simulation calculations of the rotational speeds of the spinner 11 and the orbital model 12. Furthermore, by introducing the parameter "angle at which the beam enters the spinner," the simulated trajectory information can provide sufficient theoretical reference data for the subsequent motion state detection of the spinner 11, while reducing the amount of data computation and improving work efficiency. Moreover, when the motion state of the spinner 11 is subsequently detected, the spinner speed with high accuracy can be obtained by using the data set of the number and width of the columnar peaks. The entire process is simple and fast, requiring no structural modification of the semiconductor device, saving production costs. At the same time, it eliminates the dependence on the drive pulse trigger signal detection of the semiconductor device, avoiding the influence of signal delay, and improving the stability and reliability of the entire detection process. This makes the method applicable to the motion state detection of rotating workpieces in various types of semiconductor devices.

[0112] In another aspect, the present invention provides a detection system for performing any of the rotational speed detection methods described herein, with reference to... Figure 2 The detection system includes an optical detection device 21 and a main control device 22. The optical detection device 21 is mounted on the semiconductor device and emits a detection beam to scan the substrate area and the area outside the substrate on the surface of the orbiter 12 of the semiconductor device to generate measured detection data. The detection data obtained from scanning the substrate area on the surface of the orbiter 12 differs from the detection data obtained from scanning the area outside the substrate on the surface of the orbiter 12, thus generating a pulse histogram. The main control device 22 is communicatively connected to the optical detection device 21 and pre-stores the theoretical correspondence between the theoretical number of peaks and the theoretical peak width of each standard pulse histogram under different theoretical rotational speed ratios and different entry angles of the orbiter. The main control device 22 can also be used to control the normal operation of the semiconductor device. Optionally, the detection system may also include a model building module for establishing a substrate rotation model to obtain simulated trajectory information.

[0113] In practical applications, the rotation speed detection method of this invention can accurately detect the rotation speed of the spinner 11 during its rotation. Its revolution speed can be obtained by measuring the rotation speed of the orbiter 12, thus revealing the real-time motion state of the spinner 11 throughout the entire rotation process. By comparing this with preset process parameters, the time point at which motion abnormalities occur can be determined. Taking thin film growth as an example, when using semiconductor equipment for the next process, adjusting the operating parameters of the semiconductor equipment at the abnormal time point can prevent thin film quality problems caused by abnormal motion of the spinner 11. Therefore, the rotation speed detection method and detection system of this invention can provide excellent guidance for the next process, thereby improving the processing quality of subsequent processes.

[0114] In the rotational speed detection method of this embodiment, refer to Figure 2 Taking a semiconductor growth apparatus for growing an epitaxial film on the surface of substrate 13 as an example, the semiconductor apparatus is equipped with an optical detection device 21. This optical detection device 21 is a reflectivity measurement device that can emit a detection beam to the substrate area and the area outside the substrate on the surface of the orbiter 12, and receive the reflected signal of the detection beam to form detection data. The detection beam is light within a specific wavelength range, such as laser light. The reflected signal can be, for example, light intensity information.

[0115] After the detection beam is emitted, it is incident from the dielectric onto the epitaxial film on the surface of substrate 13. At the dielectric / epitaxy film interface, a single reflection and a single refraction occur. The first-refracted ray then undergoes a second reflection at the substrate / epitaxy film interface. Once epitaxial film growth begins, both reflectivity and refractive index change with increasing optical thickness.

[0116] by Figure 2Taking the semiconductor device shown as an example, the orbital seat 12 is provided with five rotating seats 11 arranged in sequence around its axis in the circumferential direction. Each rotating seat 11 is provided with three substrates 13 arranged in sequence around its axis in the circumferential direction. The optical detection device 21 emits a detection beam to the substrate area on the surface of the rotating seat 11 and receives the corresponding reflected signal. The voltage signal information is obtained by performing conventional data processing on the reflected signal.

[0117] Figure 9 The curve showing the change in reflectance over time is presented, with the vertical axis representing relative intensity to characterize reflectance and the horizontal axis representing relative time to characterize time. Figure 9 It is evident that during the manufacturing process, although the exposed surfaces of the spinner 11 and orbiter 12 are also covered with a thin film, their compositional materials differ from those of the substrate 13. Considering heat transfer and mechanical properties, their light absorption is far superior to that of the epitaxial film, and their reflectivity is significantly weaker. Therefore, the detection data obtained by scanning the substrate area using reflectivity testing shows a significant difference between the data obtained by scanning the area outside the substrate.

[0118] In step S3 of this embodiment, the step of establishing a standard bar chart involves a first standard logic value and a second standard logic value having opposite logical high-low relationships. Specifically, the first standard logic value is logical high and the second standard logic value is logical low. For example, the first standard logic value is 1 and the second standard logic value is 0.

[0119] In the rotational speed detection method of this embodiment, taking a self-rotating seat model as an example, in a specific embodiment, in the mathematical modeling method using template matching, the rotational speed of the self-rotating seat model is assigned a value of 6 rpm, and the rotational speed of the orbital seat model is assigned a value of 1 rpm. The resulting simulated trajectory curve 32 in the self-rotating seat model is shown below. Figure 10 The red curve indicates that the detection simulation point enters the spinner model from point O1. A vertical radial line, defined as baseline 31, is taken as the starting point from the center O of the spinner model. The entry angle is the angle between baseline 31 and the line connecting baseline 31 and OO1. The simulated detection values ​​of the simulated trajectory curves in the region where the substrate model is located on the spinner model are assigned logic high, and the values ​​in other regions are assigned logic low. This yields the standard pulse histogram corresponding to the simulated trajectory information of the spinner model, as shown below. Figure 11 As shown, the standard pulse histogram shows that the number of standard peaks is 4 and the width of each standard peak is as follows: Figure 11The numbers labeled on each column peak are 16, 46, 46, and 17, respectively. The simulated trajectory curves on other rotating models on the orbital model are obtained as follows: based on the relative positions of each substrate model on other rotating models and each substrate model on this rotating model, coordinate transformation is performed in combination with the rotation speed of the rotating model and the rotation speed of the orbital model. The specific implementation method is conventional in this field.

[0120] In one specific embodiment, the obtained measured pulse histogram, for example Figure 9 The pulse columnar peak group corresponding to the fourth region from the left in the diagram has 5 columnar peaks, and the widths of each columnar peak from left to right are 21, 22, 26, 29, and 27, forming a columnar peak width data group. In the theoretical correspondence, each theoretical speed ratio and each angle of entry into the spindle corresponds to a theoretical columnar peak number and a theoretical columnar peak width data group consisting of the theoretical columnar peak width and the theoretical columnar peak width corresponding to each theoretical columnar peak. Among them, in the theoretical columnar peak width data group with 5 theoretical columnar peaks, the theoretical columnar peak widths are 24, 27, 29, 28, and 25, respectively, and the corresponding theoretical rotational speed to revolution speed ratio is 10:1. Therefore, the rotational speed can be obtained based on this theoretical rotational speed to revolution speed ratio and the revolution speed in step S4.

[0121] Due to the different angles of entry into the spinner, different theoretical rotational speeds to revolutional speeds will correspond to the same number of theoretical columnar peaks. In this case, it is necessary to compare the measured columnar peak width data set with different theoretical columnar peak width data sets under each theoretical rotational speed to revolutional speed ratio, and select the theoretical columnar peak width data set with the smallest difference as the basis for calculating the spinner speed.

[0122] In a specific embodiment, for example Figure 9The pulse columnar peak group corresponding to the fourth region from the left in the diagram has 5 columnar peaks, with peak widths of 21, 22, 26, 29, and 27 from left to right. In the theoretical correspondence, in one theoretical columnar peak width data group with 5 theoretical columnar peaks, the peak widths are 24, 27, 29, 28, and 25, corresponding to a theoretical rotational speed to revolutional speed ratio of 10:1. In another theoretical columnar peak width data group with 5 theoretical columnar peaks, the peak widths are 9, 28, 11, 44, and 7, corresponding to a theoretical rotational speed to revolutional speed ratio of 8:1. Obviously, the differences between the theoretical column peak widths of 24, 27, 29, 28 and 25 and the measured column peak widths are smaller than those of 9, 28, 11, 44 and 7. Therefore, the rotation speed can be obtained based on the theoretical rotation speed to revolution speed ratio of 10:1 and the revolution speed in step S4.

[0123] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify, alter, or combine the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for detecting rotational speed, characterized in that, include: S1: Provide a semiconductor device and an optical detection apparatus, wherein the semiconductor device includes a spin seat for supporting a substrate, a revolving seat for supporting the spin seat, a rotating device for driving the revolving seat to revolve, and a gas channel disposed on the revolving seat and used to drive the spin seat to rotate; the optical detection apparatus is used to emit a detection beam to obtain detection data of a substrate area and an outer area on the surface of the revolving seat, wherein there is a difference between the detection data of the substrate area and the outer area to generate a pulse histogram; S2: Obtain the simulated trajectory information of the model surface corresponding to the rotator under different theoretical speed ratios and different entry angles of the rotator, wherein the theoretical speed ratio is the ratio of the rotation speed of the rotator to the rotation speed of the orbital seat; S3: Establish a standard pulse histogram based on the simulated trajectory information to obtain the theoretical correspondence between the theoretical number of peaks, the theoretical peak width, the theoretical rotational speed ratio, and the angle of entry into the spindle. S4: Place the substrate on the rotating seat, control the rotating device to drive the orbital seat to revolve, provide driving gas to the gas channel to drive the rotating seat to rotate, and obtain measured detection data of the substrate area and the area outside the substrate through the optical detection device; S5: Obtain a measured pulse histogram based on the measured detection data; S6: The rotation speed of the self-rotating seat is obtained based on the measured pulse histogram, the theoretical correspondence, and the rotational speed of the orbital seat in step S4.

2. The rotational speed detection method according to claim 1, characterized in that, The measured data includes any one of reflectivity data, temperature data, or distance measurement data, and the standard pulse histogram and the measured pulse histogram show a periodic variation trend.

3. The rotational speed detection method according to claim 1, characterized in that, In step S2, center O is defined as the center of the model corresponding to the spinner. A radial line with center O of the model corresponding to the spinner as the starting point is used as the reference line. The starting intersection point of the detection simulation point corresponding to the detection beam and the edge of the model corresponding to the spinner is O1. The angle between the line connecting O and O1 and the reference line is the angle of entering the spinner.

4. The rotational speed detection method according to claim 1, characterized in that, Step S2, the step of obtaining the simulated trajectory information includes: Establish a substrate rotation model for the semiconductor device; Based on the substrate rotation model, the simulated trajectory information is obtained using a template matching mathematical modeling method.

5. The rotational speed detection method according to claim 4, characterized in that, The substrate rotation model includes a substrate model, a self-rotating model, and a revolution-oriented model. Step S2, which involves using a template-matching mathematical modeling method to obtain the simulated trajectory information, includes: S21: Provide and control the detection simulation point to enter the substrate area on the surface of the orbital seat model from a set position, and keep the relative position of the detection simulation point in the substrate rotation model unchanged; S22: Control the self-rotating model and the orbiting model to rotate at a set theoretical speed ratio; S23: Obtain the simulated trajectory curve formed by the detection simulation point on the self-rotating model; S24: Change the value of the theoretical speed ratio and / or the position of the detection simulation point entering the substrate area of ​​the orbital model surface, and repeat the above steps to obtain the simulation trajectory curves under different theoretical speed ratios and different entry angles of the orbital model.

6. The rotational speed detection method according to claim 5, characterized in that, The orbital model carries M circumferentially arranged self-rotating models, denoted as the 1st to the Mth self-rotating models, where M is a positive integer greater than 1. Step S23, the step of obtaining the simulated trajectory curve, includes: S231: During the j-th revolution period of the i-th rotational model, obtain the coordinate set of the detection simulation point on the i-th rotational model to obtain the corresponding simulation trajectory curve that changes with time; where i is a positive integer not exceeding M, j is a positive integer not exceeding K, and K is a preset number of periods. S232: Perform coordinate transformation on the simulated trajectory curve on the i-th rotating seat model to obtain the simulated trajectory curve of the detection simulation point on each of the rotating seat models during the j-th revolution period.

7. The rotational speed detection method according to claim 5, characterized in that, After step S232 is completed, the following steps are also performed: S233: Iterate through the values ​​of j and repeat steps S231 to S232 to obtain the simulated trajectory curves of the detection simulation point on each of the self-rotating models during the first to the Kth revolution periods.

8. The rotational speed detection method according to claim 5, characterized in that, The steps to create a standard pulse histogram include: The simulated detection values ​​corresponding to the substrate area on the surface of the self-rotating model in the simulated trajectory curve are set as first standard logic values, and the simulated detection values ​​corresponding to the outer substrate area on the self-rotating model are set as second standard logic values ​​lower than the first standard logic values, so as to generate the standard bar chart.

9. The rotational speed detection method according to claim 1, characterized in that, The measured detection data is reflectivity data. The number of substrates carried on the spinner is at least 2. There is a substrate spacing between two adjacent substrates on the same spinner. At least one bar peak in the measured pulse histogram has inflection point data. After step S4 is completed, the substrate spacing and the spot diameter of the detection beam are obtained, and it is determined that the spot diameter is greater than the substrate spacing. Step S5 also includes data processing of the measured pulse histogram.

10. The rotational speed detection method according to claim 1, characterized in that, The measured detection data is temperature data. The number of substrates carried on the rotating seat is at least 2. There is a substrate spacing between two adjacent substrates on the same rotating seat. After step S4 is completed, the measured pulse histogram is differentiated to obtain a differentiated pulse histogram with peak values ​​all greater than 0. When at least one peak of the differentiated pulse histogram has inflection point data, the substrate spacing and the spot diameter of the detection beam are obtained, and it is determined that the spot diameter is greater than the substrate spacing. Step S5 also includes data processing of the measured pulse histogram.

11. The rotational speed detection method according to claim 9 or 10, characterized in that, Step S5, the step of performing data processing on the measured pulse histogram, includes: The validity of the inflection point data is determined to decide whether to assign the inflection point data as the peak value of the columnar peak region or to assign the inflection point data as the bottom value of the columnar peak region to divide the columnar peak region into peaks.

12. The rotational speed detection method according to claim 11, characterized in that, The peak value and the peak value in the bar-shaped peak region where the inflection point data is located have an extreme value difference. The steps for determining the validity of the inflection point data include: If the difference between the peak value and the inflection point data does not exceed 10% of the extreme value difference, then the inflection point data is assigned the peak value. If the difference between the peak value and the inflection point data is greater than 10% of the extreme value difference, then the inflection point data is assigned the peak bottom value.

13. The rotational speed detection method according to claim 1, characterized in that, The measured pulse histogram includes pulse histogram peak groups corresponding to each of the rotating seats under one revolution period. Each pulse histogram peak group includes at least one histogram peak. In step S6, the step of obtaining the rotation speed of the rotating seat based on the measured pulse histogram, the theoretical correspondence, and the rotation speed of the revolution seat in step S4 includes: S61: Obtain the number of columnar peaks in the pulse columnar peak group corresponding to the self-rotating seat, and the columnar peak width data group composed of the widths of each columnar peak; S62: Based on the number of columnar peaks in the theoretical correspondence, obtain at least one theoretical speed ratio corresponding to the same number of columnar peaks, and a theoretical columnar peak width data group corresponding to each theoretical speed ratio; S63: Compare the differences between the column peak width data group and each of the theoretical column peak width data groups, and select the theoretical speed ratio corresponding to the theoretical column peak width data group with the smallest difference as the target speed ratio; S64: The rotational speed of the oscillator is obtained based on the target rotational speed ratio and the rotational speed of the orbital seat in step S4.

14. A detection system, characterized in that, For performing the rotational speed detection method according to any one of claims 1 to 13, the detection system comprises: An optical inspection device is used to emit a detection beam to scan the substrate area and the area outside the substrate on the surface of the orbital mount of a semiconductor device. The detection data obtained by the optical inspection device from scanning the substrate area and the detection data obtained from scanning the area outside the substrate have differences to generate a pulse histogram. The communication is connected to the main control device of the optical detection device, which has pre-stored the theoretical correspondence between the number of theoretical peaks and the theoretical peak width of each standard pulse histogram under different theoretical rotation speed ratios and different entry angles of the spindle.

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