Curvature radius measuring device and its measurement method

Abstract

The present invention relates to a curvature radius measuring device and a measuring method thereof. The curvature radius measuring device comprises a sample stage, a diffraction light array generating module and a detection and analysis module. The diffraction light array generating module generates and emits a diffraction light array to a sample. After reaching the sample surface, the diffraction light array is reflected by the sample surface to emit a reflection light array. The detection and analysis module receives the reflection light array and obtains the curvature radius of the sample according to the size of the received reflection light array. The present invention utilizes the characteristic that the diffraction light array has different array sizes when the distance between the diffraction light array and the light source is different, designs a mathematical model for measuring the curvature radius using the diffraction light array, and based on the mathematical model realizes a curvature radius measuring device with a simple structure, fast measurement speed, and low hardware requirements for lasers, sensors, etc.

Description

Technical Field

[0001] The invention relates to the technical field of thin film measurement, and in particular to a curvature radius measuring device and a measuring method thereof. Background Art

[0002] Thin film technology is widely used in optics, electronics, materials and other technical fields. However, in the process of thin film manufacturing, preparation processes such as physical vapor deposition will cause large residual stress inside the formed film, and residual stress will cause the film to bend or even device failure. The radius of curvature of the film is the most direct way to evaluate residual stress. Therefore, after the film is formed, measuring its radius of curvature is a key thin film measurement step.

[0003] The single-light-spot line scanning method is a relatively mature method for measuring the radius of curvature of thin films. The measuring light beam is reflected by the deformed sample surface, and then after optical path amplification, the offset position is collected to calculate the equivalent radius of curvature of the sample. However, the single-light-spot line scanning method requires measuring multiple sets of data (usually more than 10 sets) before calculating the radius of curvature value once. A single measurement takes more than 20 seconds, and multiple sets of measurement data are easily affected by interference such as environmental vibration, which affects the measurement results.

[0004] In order to solve the measurement time and accuracy problems of the single light spot line scanning method, the researchers proposed the parallel light array method. By changing the measurement beam to a parallel light array, the curvature radius of the sample can be calculated through a single data collection, and the influence of environmental interference on the measurement accuracy is avoided. However, the parallel light array method requires a high-quality parallel light spot array, and has high requirements for the design of optical devices. The manufacturing cost of Etalon, the most commonly used optical device for generating parallel light arrays, is very high, and the brightness of the generated light beam end is low, so it has high requirements for laser intensity, sensor sensitivity, and reflectivity of the sample surface. Summary of the invention

[0005] Based on this, it is necessary to provide a curvature radius measuring device and a measuring method thereof to address the problem that the existing curvature radius measurement method has high requirements on laser intensity, sensor sensitivity and reflectivity of the sample surface.

[0006] In order to achieve the purpose of the present invention, the present invention adopts the following technical solution:

[0007] A curvature radius measuring device, comprising:

[0008] A sample stage, used for carrying a sample to be measured;

[0009] A diffraction light array generation module is used to generate and emit a diffraction light array to a sample;

[0010] The detection and analysis module is used to receive the reflected light array emitted by the sample and obtain the curvature radius of the sample according to the size of the received reflected light array.

[0011] In one embodiment, the detection and analysis module includes:

[0012] A sensor imaging screen, used for receiving the reflected light array emitted by the sample and converting the optical signal of the reflected light array into an electrical signal;

[0013] The analysis unit is electrically connected to the sensor imaging screen and is used to obtain the curvature radius of the sample according to the electrical signal.

[0014] In one embodiment, the emission direction of the diffraction light array is perpendicular to the sample stage, and the curvature radius of the sample is calculated according to the following formula:

[0015]

[0016] in,

[0017] R is the radius of curvature of the sample;

[0018] S is the length of the first path of the diffraction light array from the diffraction light array generation module to the sample surface;

[0019] H is the length of the second path of the reflected light array from the sample surface to the sensor imaging screen;

[0020] β is the divergence angle of the diffraction light array;

[0021] D is the distance between the actual landing point of the reflected light array on the detector and the set landing point.

[0022] In one embodiment, the curvature radius measuring device further comprises a semi-reflective semi-mirror lens, wherein the semi-reflective semi-mirror lens is disposed between the diffraction light array generating module and the sample stage, and the angle between the semi-reflective semi-mirror lens and the sample stage is 45°;

[0023] The diffracted light array passes through the semi-reflective and semi-mirror lens to reach the sample surface, and then is reflected by the sample surface and the semi-reflective and semi-mirror lens to be projected onto a sensor imaging screen vertically arranged to the sample stage.

[0024] In one embodiment, the sample stage comprises:

[0025] A table for carrying samples to be measured;

[0026] The two-dimensional motion mechanism is used to drive the table to move horizontally.

[0027] In one embodiment, the diffraction light array generating module includes:

[0028] a laser for emitting an initial probe beam;

[0029] The diffraction optical lens is used to convert the initial detection light beam into a diffraction light array.

[0030] The technical solution of the present invention also provides a method for measuring the radius of curvature, comprising:

[0031] Place the sample on the sample stage;

[0032] emitting a diffracted light array to the surface of the sample;

[0033] receiving a reflected light array emitted by a sample;

[0034] The single-point curvature radius of the sample is obtained according to the reflected light array.

[0035] In one embodiment, before the step of placing the sample on the sample stage, the step further includes: calibrating the mechanical parameters of the curvature radius measuring device.

[0036] In one embodiment, the step of calibrating the mechanical parameters of the curvature radius measuring device includes:

[0037] Placing the first calibration sheet on the sample stage;

[0038] emitting a diffracted light array to the surface of the first correction plate;

[0039] receiving a first reflected light array emitted by a first calibration plate;

[0040] Replace the first correction plate with a second correction plate, and repeat the above steps of emitting a diffracted light array and receiving a reflected light array to obtain a second reflected light array;

[0041] Acquire mechanical parameter correction data of a curvature radius measuring device according to the first reflected light array, the second reflected light array, and the curvature radii of the first correction sheet and the second correction sheet;

[0042] The calibration data is imported into the analysis unit.

[0043] In one embodiment, after the step of obtaining the single-point curvature radius, the method further includes:

[0044] Move the sample stage according to the set direction and step length;

[0045] emitting a diffracted light array to the surface of the sample;

[0046] receiving a reflected light array emitted by a sample;

[0047] According to the reflected light array, obtaining a single-point curvature radius of the current position of the sample;

[0048] Determine whether the current position is the final position. If so, end the measurement and output the multi-point curvature radius of the sample; otherwise, repeat the above steps of moving the sample stage, emitting the diffraction light array and receiving the reflected light array to obtain the curvature radius of the next position of the sample.

[0049] In one embodiment, after the step of obtaining the multi-point curvature radius of the sample, the method further includes: drawing a curvature radius distribution diagram of the sample based on the multi-point curvature radius.

[0050] The above-mentioned curvature radius measuring device includes a sample stage, a diffraction light array generating module and a detection and analysis module. The diffraction light array generating module generates and emits a diffraction light array to the sample. After reaching the sample surface, the diffraction light array is reflected by the sample surface to emit a reflected light array. The detection and analysis module receives the reflected light array and obtains the curvature radius of the sample according to the size of the received reflected light array. Each laser beam in the diffraction light array has a certain angle with the central light beam, so the size of the spot array will be different when the distance from the light source is different. The present invention utilizes the characteristic of the diffraction light array that the array size is different when the distance is different, designs a mathematical model for measuring the curvature radius using the diffraction light array, and implements the curvature radius measuring device based on the mathematical model. The diffraction optical device has a low degree of customization and is easy to process. Moreover, the brightness of each beam of the generated spot array is similar, which effectively avoids the problem of high hardware requirements caused by the low brightness of some beams in the prior art, thereby realizing a curvature radius measuring device with simple structure, fast measurement speed, and low hardware requirements for lasers, sensors, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a schematic diagram of a calculation model of a curvature radius measurement device in an embodiment;

[0052] Figure 2 is a schematic structural diagram of a curvature radius measuring device in one embodiment;

[0053] Figure 3 is a schematic diagram of a diffraction light array in an embodiment;

[0054] Figure 4 is a flow chart of a method for measuring a radius of curvature in one embodiment;

[0055] Figure 5 is a flow chart of step S500 of a method for measuring a radius of curvature in an embodiment;

[0056] Figure 6 FIG. 4 is a flow chart of a multi-point curvature radius measurement method in one embodiment. DETAILED DESCRIPTION

[0057] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0059] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the method or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0060] An embodiment of the present invention provides a device for measuring a radius of curvature, comprising:

[0061] The sample stage 100 is used to carry the sample to be measured;

[0062] A diffraction light array generation module 200 is used to generate and emit a diffraction light array to a sample;

[0063] The detection and analysis module is used to receive the reflected light array emitted by the sample and obtain the curvature radius of the sample according to the size of the received reflected light array.

[0064] Figure 1 Schematic diagram of the calculation model of the curvature radius measurement device of this embodiment. The diffracted light array is emitted from the light source O. After the emitted diffracted light array reaches the sample surface ( Figure 1 The bold solid line in the figure is the sample surface), and after being reflected by the sample surface, a reflected light array is emitted to reach the light receiving plane.

[0065] In this calculation model, it is assumed that the diffraction light array includes two light rays, wherein the light emitting in a direction perpendicular to the tangent direction of the point to be measured on the sample surface is defined as the first light ray, and the other light emitting in a direction different from the first light ray is defined as the second light ray, and the second light irradiates point A on the sample surface, and the angle between the first light ray and the second light ray is β, and the angle between O'A and O'O is α (O' is the center of the virtual circle where the sample is located, and the radius of the virtual circle is the sample curvature radius R). First, assuming that the radius of curvature of the thin film sample is infinite, that is, the sample is a plane without curvature, then the set landing point of the reflected light of the second light ray on the light receiving plane is P1; however, the actual radius of curvature of the thin film sample is not infinite, then the actual landing point of the reflected light on the light receiving plane is P2, and there is a certain offset distance D between the positions of P1 and P2. In addition, the distance from the light source point O to the sample surface is defined as S, the vertical distance from the sample surface point A to the light receiving plane is defined as H, and the vertical distance from point A to O'O is defined as W. The parameters α, β, R, D, S, H, and W satisfy the following calculation formula:

[0066] D=KP2-KP1=Htan(2α+β)-Htan(β) (1)

[0067]

[0068] In addition, the curvature radius of the sample caused by the thin film deposition process is usually greater than 5m, and the distance between the first light and the second light falling on the sample surface is no more than 5mm. Therefore, the following approximate calculation formula can be obtained:

[0069] W≈Stan(β) (3)

[0070] cos(α)≈1 (4)

[0071] By solving the formula (1) to the formula (4), the following curvature radius calculation formula can be obtained:

[0072]

[0073] Furthermore, based on the premise that the curvature radius of the aforementioned sample is usually greater than 5m, and the distance between the first light and the second light irradiating the sample surface is no more than 5mm, the gap between the sample and the sample stage 100 is extremely small, S can be approximately equal to the distance from the light source O point to the surface of the sample stage 100, and H can be approximately equal to the distance from the surface of the sample stage 100 to the light receiving plane, so S and H can be considered as the inherent mechanical parameters of the curvature radius measurement device. And β is the divergence angle of the diffracted light array, so β ​​is the inherent optical parameter of the scattered light array. Then the parameters S, H and β in the curvature radius calculation formula are all known numbers. According to the measurement result of the offset distance D, the curvature radius R of the sample can be obtained using the curvature radius calculation formula.

[0074] According to the curvature radius calculation formula, based on this calculation model, the curvature radius of a point on the sample surface can be obtained with only one measurement, without the need to continuously acquire multiple sets of data for measurement, thus avoiding the influence of interference such as vibration on the results of different sets of data, thereby realizing a curvature radius measurement model with faster measurement speed and more accurate results.

[0075] In one embodiment, the detection and analysis module includes:

[0076] The sensor imaging screen 310 is used to receive the reflected light array emitted by the sample and convert the optical signal of the reflected light array into an electrical signal;

[0077] The analysis unit is electrically connected to the sensor imaging screen 310 and is used to obtain the curvature radius of the sample according to the electrical signal.

[0078] like Figure 2 As shown, the sensor imaging screen 310 is the aforementioned light receiving plane, and the analysis unit is a data processing device electrically connected to the sensor imaging screen 310, such as a computer (not shown in the figure). In one example, the sensor imaging screen 310 is composed of a CCD image sensor with a measurement accuracy of 10um, that is, it can distinguish two light rays with a landing distance of not less than 10um, so as to accurately measure the reflected light array with a distance between adjacent light spots of not less than 10um. After the sensor imaging screen 310 obtains the reflected light array, it sends an electrical signal to the analysis unit, and the analysis unit obtains the curvature radius of the sample according to the curvature radius calculation formula.

[0079] In this example, H and S of the curvature radius measuring device are both less than 1m. Based on the sensor imaging screen 310 with a measurement accuracy of 10um, the curvature radius measuring device in this example can be used to measure samples with a curvature radius range of 5m to 200m, and the system error is less than ±1%. Furthermore, the corresponding H and S can be selected according to the curvature radius of the sample. For example, when the curvature radius is large, a larger distance H from the sample to the sensor imaging screen 310 is selected, thereby amplifying the reflected light array to obtain a more accurate measurement result.

[0080] In one embodiment, the diffraction light array generating module 200 includes:

[0081] Laser 210, for emitting an initial probe beam;

[0082] The diffraction optical lens 220 is used to convert the initial detection light beam into a diffraction light array.

[0083] In one example, the diffraction light array is as follows Figure 3 As shown in the 5×5 light spot array, it can be understood that the more light spots the diffraction light array contains, the more points projected onto the sensor imaging screen 310, that is, more points can be used to calculate the curvature radius of the sample, thereby obtaining a higher measurement accuracy. However, under the premise that the luminous intensity of the laser 210 remains unchanged, the light intensity of each light spot obtained after the conversion by the diffraction optical lens 220 is inversely proportional to the number of light spots. Further, if the divergence angle β of the formed diffraction light array remains unchanged, the distance between each light spot is also inversely proportional to the number of light spots. The light intensity of the light spot and the distance between adjacent light spots will put forward corresponding requirements for the measurement accuracy of the sensor imaging screen 310. The higher the measurement accuracy requirement means the higher manufacturing difficulty and manufacturing cost. Therefore, an appropriate diffraction optical lens 220 should be selected to generate a diffraction light array with an appropriate number of light spots, so as to better balance the relationship between measurement accuracy and manufacturing cost.

[0084] In one embodiment, if Figure 2 As shown, the curvature radius measuring device further includes a semi-reflective semi-mirror lens 400, which is disposed between the diffraction light array generating module 200 and the sample stage 100, and the angle between the semi-reflective semi-mirror lens 400 and the sample stage 100 is 45°;

[0085] The diffracted light array passes through the semi-reflective and semi-mirror lens 400 to reach the sample surface, and then is reflected by the sample surface and the semi-reflective and semi-mirror lens 400 to be projected onto the sensor imaging screen 310 which is vertically arranged with respect to the sample stage 100 .

[0086] By changing the emission direction of the reflected light array through the semi-reflective and semi-mirror sheet 400, the laser 210 and the diffractive optical lens 220 can be prevented from blocking the reflected light array, thereby obtaining a complete reflected light array on the sensor imaging screen 310. In this embodiment, S is the path length from the diffractive optical lens 220 to the sample surface, and H is the sum of the path length H1 from the sample surface to the semi-reflective and semi-mirror sheet 400 and the path length H2 from the semi-reflective and semi-mirror sheet 400 to the sensor imaging screen 310.

[0087] In one embodiment, the sample stage 100 includes a table top and a two-dimensional motion mechanism, wherein the table top is used to carry the sample to be measured, and the two-dimensional motion mechanism is used to drive the table top to move horizontally. Through the horizontal motion, the curvature radius within a set range of the sample can be measured according to a preset measurement logic, so that only one parameter setting is required to automatically measure and obtain the curvature radius measurement data of multiple points in the sample, thereby improving the operability and flexibility of the curvature radius measurement device.

[0088] The technical solution of the present invention also provides a method for measuring the radius of curvature, such as Figure 4 As shown, including:

[0089] S100: placing a sample on a sample stage 100;

[0090] S200: emitting a diffracted light array to the surface of the sample;

[0091] S300: receiving a reflected light array emitted by a sample;

[0092] S400: Acquire a single-point curvature radius of a sample according to the reflected light array.

[0093] In one embodiment, before the step of placing the sample on the sample stage 100, the method further includes S500: calibrating the mechanical parameters of the curvature radius measuring device. According to the curvature radius calculation formula, it is necessary to calculate the curvature radius of the sample according to the mechanical parameters H and S inherent in the curvature radius measuring device, but the mechanical parameters H and S may vary to a certain extent due to factors such as external vibration, thereby affecting the calculation result of the curvature radius. Therefore, the step of calibrating the mechanical parameters can further improve the accuracy of the curvature radius measuring device.

[0094] In one example, if Figure 5 As shown, the step of correcting the mechanical parameters of the curvature radius measuring device includes:

[0095] S510: placing a first calibration sheet on the sample stage 100;

[0096] S520: emitting a diffracted light array to the surface of the first correction plate;

[0097] S530: receiving a first reflected light array emitted by a first calibration sheet;

[0098] S540: replacing the first correction plate with a second correction plate, and repeating the above steps of emitting a diffracted light array and receiving a reflected light array to obtain a second reflected light array;

[0099] S550: Acquire mechanical parameter calibration data of a curvature radius measuring device according to the first reflected light array, the second reflected light array, and the curvature radii of the first correction sheet and the second correction sheet;

[0100] S560: Importing the calibration data into the analysis unit.

[0101] In this example, it is known that the curvature radius of the first correction plate is R1, and the curvature radius of the second correction plate is R2. By substituting R1 and R2 as known numbers into the curvature radius calculation formula, the accurate correction data of H and S can be solved, and the analysis unit can obtain the accurate sample curvature radius R based on the correction data.

[0102] In one embodiment, if Figure 6 As shown, after the step of obtaining the single-point curvature radius, the method further includes:

[0103] S610: moving the sample stage 100 according to the set direction and step length;

[0104] S620: emitting a diffracted light array to the surface of the sample;

[0105] S630: receiving a reflected light array emitted by a sample;

[0106] S640: acquiring a single-point curvature radius of a current position of the sample according to the reflected light array;

[0107] S650: Determine whether the current position is the final position. If so, end the measurement and output the multi-point curvature radius of the sample; otherwise, repeat the above steps of moving the sample stage 100, emitting the diffraction light array and receiving the reflected light array to obtain the curvature radius of the next position of the sample.

[0108] Through the multi-point measurement steps in this embodiment, the curvature radius within the set range of the sample can be measured according to the preset measurement logic, so that only one parameter setting is required to automatically measure and obtain the curvature radius measurement data of multiple points in the sample, thereby improving the operability and flexibility of the curvature radius measurement. Specifically, the operator selects a measurement area on the sample surface and sets the measurement step length. The control component of the two-dimensional motion mechanism automatically plans the measurement path in the measurement area according to the measurement step length. After each single-point measurement, the two-dimensional motion mechanism controls the sample to move according to the measurement path until the current position is the final position in the measurement path.

[0109] In one embodiment, after the step of obtaining the multi-point curvature radius of the sample, the method further includes: drawing a curvature radius distribution diagram of the sample according to the multi-point curvature radius. Through the curvature radius distribution diagram, the curvature radius distribution of the sample can be intuitively obtained and analyzed, and the process parameters of the thin film deposition can be further adjusted or bad samples can be eliminated, thereby improving the overall production yield of the device.

[0110] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A curvature radius measuring device, characterized in that: include: A sample stage, used for carrying a sample to be measured; A diffraction light array generating module, used for generating and emitting a diffraction light array to a sample, wherein the emitting direction of the diffraction light array is perpendicular to the sample stage; A sensor imaging screen, used for receiving the reflected light array emitted by the sample and converting the optical signal of the reflected light array into an electrical signal; The analysis unit is electrically connected to the sensor imaging screen and is used to calculate the curvature radius of the sample according to the electrical signal using the following formula: in, R is the radius of curvature of the sample; S is the length of the first path of the diffraction light array from the diffraction light array generation module to the sample surface; H is the length of the second path of the reflected light array from the sample surface to the sensor imaging screen; β is the divergence angle of the diffraction light array; D is the distance between the actual landing point of the reflected light array on the detector and the set landing point.

2. The curvature radius measuring device according to claim 1, characterized in that: The curvature radius measuring device further comprises a semi-reflective semi-mirror lens, wherein the semi-reflective semi-mirror lens is arranged between the diffraction light array generating module and the sample stage, and the angle between the semi-reflective semi-mirror lens and the sample stage is 45°; The diffracted light array passes through the semi-reflective and semi-mirror lens to reach the sample surface, and then is reflected by the sample surface and the semi-reflective and semi-mirror lens to be projected onto a sensor imaging screen vertically arranged to the sample stage.

3. The curvature radius measuring device according to claim 1, characterized in that: The sample stage comprises: A table for carrying samples to be measured; The two-dimensional motion mechanism is used to drive the table to move horizontally.

4. The curvature radius measuring device according to claim 1, characterized in that: The diffraction light array generating module comprises: a laser for emitting an initial probe beam; The diffraction optical lens is used to convert the initial detection light beam into a diffraction light array.

5. A method for measuring a radius of curvature, comprising: Place the sample on the sample stage; emitting a diffraction light array to the surface of the sample, wherein the emission direction of the diffraction light array is perpendicular to the sample stage; receiving a reflected light array emitted by a sample; According to the reflected light array, the single-point curvature radius of the sample is obtained using the following formula: in, R is the radius of curvature of the sample; S is the length of the first path of the diffraction light array from the diffraction light array generation module to the sample surface; H is the length of the second path of the reflected light array from the sample surface to the sensor imaging screen; β is the divergence angle of the diffraction light array; D is the distance between the actual landing point of the reflected light array on the detector and the set landing point.

6. The method for measuring the radius of curvature according to claim 5, characterized in that: Before the step of placing the sample on the sample stage, the method further includes: calibrating the mechanical parameters of the curvature radius measuring device.

7. The method for measuring the radius of curvature according to claim 6, characterized in that: The step of correcting the mechanical parameters of the curvature radius measuring device comprises: Placing the first calibration sheet on the sample stage; emitting a diffracted light array to the surface of the first correction plate; receiving a first reflected light array emitted by a first calibration plate; Replace the first correction plate with a second correction plate, and repeat the above steps of emitting a diffracted light array and receiving a reflected light array to obtain a second reflected light array; Acquire mechanical parameter correction data of a curvature radius measuring device according to the first reflected light array, the second reflected light array, and the curvature radii of the first correction sheet and the second correction sheet; The calibration data is imported into the analysis unit.

8. The method for measuring the radius of curvature according to claim 7, characterized in that: After the step of obtaining the single-point curvature radius, the method further includes: Move the sample stage according to the set direction and step length; emitting a diffracted light array to the surface of the sample; receiving a reflected light array emitted by a sample; According to the reflected light array, obtaining a single-point curvature radius of the current position of the sample; Determine whether the current position is the final position. If so, end the measurement and output the multi-point curvature radius of the sample; otherwise, repeat the above steps of moving the sample stage, emitting the diffraction light array and receiving the reflected light array to obtain the curvature radius of the next position of the sample.

9. The method for measuring the radius of curvature according to claim 8, characterized in that: After the step of obtaining the multi-point curvature radius of the sample, the method further includes: drawing a curvature radius distribution diagram of the sample according to the multi-point curvature radius.

Images