A measurement system, a measurement method, and a storage medium

Abstract

The present application provides a measurement system, a measurement method, and a storage medium. The light emitted by the light source module passes through a polarizer and then irradiates the sample to be measured. During the focusing process, the light reflected by the sample to be measured passes through an analyzer and then reaches a beam splitter. The beam splitter divides the light into a first light beam and a second light beam. The first light beam is incident on a first detection element, and the second light beam is reflected by a first mirror and then incident on a second detection element. A differential calculation is performed on the first detection result of the first detection element and the second detection result of the second detection element to obtain the focusing position of the light emitted by the light source module. Neither the first light beam nor the second light beam is incident on the optical detection unit. During the measurement process, the light reflected by the sample to be measured is incident on the optical detection unit, realizing the separation of the focusing process and the measurement process, avoiding the influence of using the beam splitter for focusing on the measurement process, and achieving high-efficiency and high-precision focusing.

Description

Technical Field

[0001] The present invention relates to the field of optics, and particularly to a measurement system, a measurement method, and a storage medium. Background Art

[0002] In the current ellipsometric thin film thickness measurement system, the light emitted by the light source module passes through a polarizer and irradiates the surface of an object. The light reflected from the surface of the object passes through an analyzer and is incident on the optical detection unit, thereby realizing the measurement of the thickness of the ellipsometric thin film.

[0003] When the light emitted by the light source module irradiates the surface of the object, whether the light is focused will affect the measurement accuracy of the thickness of the ellipsometric thin film, that is, whether the object is located at the focal position of the light affects the measurement accuracy.

[0004] Currently, a beam splitter is set in the ellipsometric thin film thickness measurement system to split the light passing through the analyzer. Approximately 4% - 10% of the light is used for focusing, and the remaining light is used for measuring the thickness of the ellipsometric thin film. Although there is light for focusing, the focusing efficiency and focusing accuracy are both low, and the high-efficiency and high-accuracy focusing requirements cannot be met. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a measurement system, a measurement method, and a storage medium, which can determine the focal position of the light by means of differential detection, and achieve high-efficiency and high-accuracy focusing.

[0006] To achieve the above purpose, this application has the following technical solutions:

[0007] This application provides a measurement system, including: a light source module, a focusing component, a measurement component, and a control device; the focusing component includes a beam splitter, a first reflector, and a differential detector, and the differential detector includes a first detection element and a second detection element; the measurement component includes a polarizer, an analyzer, and an optical detection unit;

[0008] The light source module is used to emit light, and the light irradiates the sample to be measured after passing through the polarizer;

[0009] When the beam splitter is located in the optical path of the light reflected by the sample to be measured, it is used to divide the light reflected by the sample to be measured and passing through the analyzer into a first light and a second light;

[0010] The first light is incident on the first detection element; the second light is reflected by the first reflector to the second detection element; the control device is used to calculate the focal position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element;

[0011] When the beam splitter deviates from the light reflected by the sample to be measured, the light reflected by the sample to be measured is incident on the optical detection unit.

[0012] Optionally, the focusing assembly further includes: a second reflector and a third reflector;

[0013] The first light is reflected back to the beam splitter by the second reflector, the beam splitter is configured to reflect the first light to the third reflector again, and the third reflector is configured to make the first light incident on the first detection element.

[0014] Optionally, the first detection result is a first offset of the light spot with respect to the pixel origin position when the first light is incident on the first detection element, and the second detection result is a second offset of the light spot with respect to the pixel origin position when the second light is incident on the second detection element;

[0015] The control device is configured to calculate the focusing position of the light emitted by the light source module according to the corresponding relationship between the first offset, the second offset, the total offset, and the sample position movement amount, and the total offset is calculated according to the first offset and the second offset.

[0016] Optionally, the system further includes a calibration mode. In the calibration mode, the beam splitter is located in the optical path of the light reflected by the sample to be measured, and is configured to divide the light reflected by the sample to be measured and passing through the analyzer into a third light and a fourth light;

[0017] The control device is configured to obtain the sample position movement amount, a third offset of the light spot with respect to the pixel origin position when the third light is incident on the first detection element, and a fourth offset of the light spot with respect to the pixel origin position when the fourth light is incident on the second detection element;

[0018] The control device is configured to calculate a total offset according to the third offset and the fourth offset;

[0019] The control device is configured to construct a corresponding relationship between the total offset and the sample position movement amount according to the total offset and the sample position movement amount.

[0020] Optionally, the first detection result is a first position point of the light spot when the first light is incident on the first detection element, and the second detection result is a second position point of the light spot when the second light is incident on the second detection element;

[0021] The control device is configured to calculate the focusing position of the light emitted by the light source module according to the correspondence between the first position point, the second position point, the first position point and the position of the sample to be measured, and the correspondence between the second position point and the position of the sample to be measured.

[0022] Optionally, it further includes: a first moving platform;

[0023] The beam splitter and the first detection element are arranged on the first moving platform, and the first moving platform is configured to drive the beam splitter and the first detection element to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured.

[0024] Optionally, the first moving platform includes a first sub-moving platform and a second sub-moving platform; the beam splitter is arranged on the first sub-moving platform, and the first detection element is arranged on the second sub-moving platform;

[0025] The first sub-moving platform is configured to drive the beam splitter to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured;

[0026] The second sub-moving platform is configured to drive the first detection element to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured.

[0027] Optionally, it further includes: a second moving platform;

[0028] The beam splitter and the second reflector are arranged on the second moving platform, and the second moving platform is configured to drive the beam splitter and the second reflector to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured.

[0029] Optionally, the second moving platform includes a third sub-moving platform and a fourth sub-moving platform; the beam splitter is arranged on the third sub-moving platform, and the second reflector is arranged on the fourth sub-moving platform;

[0030] The third sub-moving platform is configured to drive the beam splitter to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured;

[0031] The fourth sub-moving platform is configured to drive the second reflector to move into the optical path of the light reflected by the sample to be measured or deviate from the light reflected by the sample to be measured.

[0032] Optionally, the focusing assembly further includes: a rotary motor;

[0033] The rotating motor is used to drive the first moving platform or the second moving platform to perform rotational movement, the rotation axis is perpendicular to the propagation direction of the light reflected by the sample to be measured and passing through the analyzer, the rotation axis is located between the analyzer and the beam splitter, and the rotation direction is away from or towards the direction of the light reflected by the sample to be measured.

[0034] Optionally, the focusing component further includes: a linear motor;

[0035] The linear motor is used to drive the first moving platform or the second moving platform to perform translational movement, and the translational direction is away from or towards the direction of the light reflected by the sample to be measured.

[0036] Optionally, the control device is used to control the movement of the first moving platform or the second moving platform so that the beam splitter moves into the optical path of the light reflected by the sample to be measured or the beam splitter moves away from the light reflected by the sample to be measured.

[0037] Optionally, the measurement system further includes: a placement platform; the placement platform is used to place the sample to be measured;

[0038] The control device is used to control the movement of the placement platform to move the sample to be measured to the focusing position.

[0039] Optionally, the light source module emits a broadband light source, and the optical detection unit is a photodetector.

[0040] Optionally, the measurement component further includes a first compensator, a second compensator, a first objective lens, and a second objective lens. The first compensator is arranged between the polarizer and the sample to be measured, the second compensator is arranged between the analyzer and the sample to be measured, the first objective lens is arranged between the first compensator and the sample to be measured, and the second objective lens is arranged between the second compensator and the sample to be measured.

[0041] This application provides a measurement method, including:

[0042] Controlling the light source module to emit light, which passes through the polarizer and then irradiates the sample to be measured; controlling the beam splitter to move into the optical path of the light reflected by the sample to be measured, and the light reflected by the sample to be measured and passing through the analyzer is divided into a first light ray and a second light ray by the beam splitter; the first light ray is incident on the first detection element; the second light ray is reflected by the second mirror and then incident on the second detection element;

[0043] Obtaining a first detection result of the first detection element and a second detection result of the second detection element;

[0044] Calculating the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element;

[0045] Control the beam splitter to move away from the light reflected by the sample to be measured, so that the light reflected by the sample to be measured is incident on the optical detection unit.

[0046] Optionally, the first detection result is the first offset of the light spot relative to the pixel origin position when the first light is incident on the first detection element, and the second detection result is the second offset of the light spot relative to the pixel origin position when the second light is incident on the second detection element;

[0047] Calculating the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element includes:

[0048] Calculate the focusing position of the light emitted by the light source module according to the corresponding relationship between the first offset, the second offset, the total offset and the sample position movement amount, and the total offset is calculated according to the first offset and the second offset.

[0049] Optionally, the method further includes:

[0050] Obtain the sample position movement amount, the third offset of the light spot relative to the pixel origin position when the third light divided by the beam splitter is incident on the first detection element, and the fourth offset of the light spot relative to the pixel origin position when the fourth light divided by the beam splitter is incident on the second detection element;

[0051] Calculate the total offset according to the third offset and the fourth offset;

[0052] Construct the corresponding relationship between the total offset and the sample position movement amount according to the total offset and the sample position movement amount.

[0053] The present application provides a computer storage medium for storing a computer program, which when running on a computer device, causes the computer device to execute the method described in any one of the above.

[0054] The present application provides a measurement system, which includes a light source module, a focusing component, a measurement component, and a control device. The focusing component includes a beam splitter, a first mirror, and a differential detector. The differential detector includes a first detection element and a second detection element. The measurement component includes a polarizer, an analyzer, and an optical detection unit. The light source module emits light, which irradiates a sample to be measured after passing through the polarizer. During the focusing process, the beam splitter is disposed between the analyzer and the optical detection unit. The light reflected by the sample to be measured from the light source module passes through the analyzer and then reaches the beam splitter. The beam splitter divides the light reflected by the sample to be measured into a first light beam and a second light beam, that is, the beam splitter divides a beam of light reflected by the sample to be measured into two light beams. The first light beam is incident on the first detection element, and the second light beam is reflected by the first mirror and then incident on the second detection element. That is, two detection elements are used to capture the two light beams separated by the beam splitter respectively, and the detection results of the two light beams incident on the two detection elements are obtained respectively. The control device calculates the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element. That is, the control device obtains the detection results of the two light beams respectively obtained based on the first detection element and the second detection element, and determines the focusing state of the sample to be measured through differential detection analysis based on the two detection results, so as to obtain the focusing position. At this time, neither the first light beam nor the second light beam is incident on the optical detection unit. During the measurement process, the beam splitter deviates from the light reflected by the sample to be measured, and the light reflected by the sample to be measured is incident on the optical detection unit, realizing the separation of the focusing process and the measurement process, and avoiding the influence of focusing using the beam splitter on the measurement process. Based on this, the present application divides the light into two beams by using a beam splitter, and performs differential calculation on the detection results obtained by the first detection element and the second detection element to determine the focusing position of the light, realizing high-efficiency and high-precision focusing, and the beam splitter does not affect the measurement process, thereby improving the measurement accuracy of the measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for describing the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 FIG. 1 shows a schematic structural diagram of a measurement system provided by an embodiment of the present application;

[0057] Figure 2 FIG. 2 shows a schematic structural diagram of another measurement system provided by an embodiment of the present application;

[0058] Figure 3 FIG. 3 shows a schematic structural diagram of a focusing component provided by an embodiment of the present application;

[0059] Figure 4 shows a schematic structural diagram of another focusing component provided by an embodiment of the present application;

[0060] Figure 5 shows a schematic structural diagram of yet another focusing component provided by an embodiment of the present application;

[0061] Figure 6 shows a schematic structural diagram of yet another measurement system provided by an embodiment of the present application;

[0062] Figure 7 shows a schematic flowchart of a measurement method provided by an embodiment of the present application. Detailed implementation manners

[0063] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings.

[0064] In the following description, many specific details are set forth to facilitate a thorough understanding of the present application. However, the present application may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0065] The present application will be described in detail with reference to the schematic diagrams. When detailing the embodiments of the present application, for ease of explanation, the cross-sectional views showing the device structure will be enlarged locally out of the general scale, and the schematic diagrams are only examples and should not limit the scope of protection of the present application herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0066] The current ellipsometric thin film thickness measurement system includes a light source module, a polarizer, a beam splitter, an analyzer, and an optical detection unit. The light emitted by the light source module irradiates the surface of an object after passing through the polarizer, and the light reflected from the surface of the object enters the optical detection unit after passing through the analyzer, thereby realizing the thickness measurement of the ellipsometric thin film.

[0067] Considering that when the light emitted by the light source module irradiates the surface of an object, whether the light is focused will affect the measurement accuracy of the thickness of the elliptical polarization film, that is, whether the object is located at the focal position of the light, which affects the measurement accuracy. Therefore, in the prior art, a beam splitter is usually set in the elliptical polarization film thickness measurement system to split the light passing through the analyzer. Approximately 4% - 10% of the light is used for focusing, and the remaining light is used for measuring the thickness of the elliptical polarization film. That is to say, the light used for thickness measurement is the light obtained after being split by the beam splitter. For a broadband light source, the beam splitter will introduce chromatic dispersion in the measurement light, that is, introduce chromatic dispersion in the elliptical polarization signal, reducing the measurement accuracy of the elliptical polarization film thickness measurement. That is to say, the light split by the beam splitter is directly used for both measurement and focusing at the same time, resulting in the beam splitter for separating the measurement light and the focusing light affecting the measurement process. During the measurement process, the beam splitter will also introduce aberration, resulting in a decrease in measurement accuracy.

[0068] And although a part of the light is used for focusing by using a beam splitter, and the maximum reflection spectrum is used to determine the focal position, the calculation method of using the maximum reflection spectrum to determine the focal position is slow, and the efficiency of focusing is low. Considering the influence of the above beam splitter on the focusing accuracy, the current situation cannot meet the high-efficiency and high-precision focusing requirements.

[0069] Based on this, the present application provides a measurement system, which includes a light source module, a focusing component, a measurement component, and a control device. The focusing component includes a beam splitter, a first mirror, and a differential detector. The differential detector includes a first detection element and a second detection element. The measurement component includes a polarizer, an analyzer, and an optical detection unit. The light source module emits light, which is irradiated on the sample to be measured after passing through the polarizer. During the focusing process, the beam splitter is disposed between the analyzer and the optical detection unit. The light reflected by the sample to be measured from the light source module passes through the analyzer and then reaches the beam splitter. The beam splitter divides the light reflected by the sample to be measured into a first light beam and a second light beam, that is, the beam splitter divides a beam of light reflected by the sample to be measured into two light beams. The first light beam is incident on the first detection element, and the second light beam is reflected by the first mirror and then incident on the second detection element. That is, two detection elements are used to capture the two light beams separated by the beam splitter respectively, and the detection results of the two light beams incident on the two detection elements are obtained respectively. The control device calculates the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element. That is, the control device obtains the detection results of the two light beams respectively obtained based on the first detection element and the second detection element, and determines the focusing state of the sample to be measured by performing differential detection analysis based on the two detection results, so as to obtain the focusing position. At this time, neither the first light beam nor the second light beam is incident on the optical detection unit. During the measurement process, the beam splitter deviates from the light reflected by the sample to be measured, and the light reflected by the sample to be measured is incident on the optical detection unit, realizing the separation of the focusing process and the measurement process, and avoiding the influence of using the beam splitter for focusing on the measurement process. Based on this, the present application divides the light into two beams by using a beam splitter, and performs differential calculation on the detection results obtained by the first detection element and the second detection element to determine the focusing position of the light, realizing high-efficiency and high-precision focusing, and the beam splitter does not affect the measurement process, thereby improving the measurement accuracy of the measurement system.

[0070] To better understand the technical solutions and technical effects of the present application, the following will describe specific embodiments in detail with reference to the accompanying drawings.

[0071] Reference Figure 1 As shown, it is a schematic structural diagram of a measurement system provided by an embodiment of the present application. The measurement system provided by the embodiment of the present application includes: a light source module 100, a focusing component, a measurement component, and a control device.

[0072] In the embodiment of the present application, the light source module 100 is used to emit light for light focusing and ellipsometric thin film thickness measurement. The light source included in the light source module 100 is a broadband light source, and the optical detection unit 330 is a spectrometer. In other embodiments, the light source can also be a narrowband light source, and the optical detection unit 330 is a photodetector.

[0073] The measurement component is used for measuring the thickness of an elliptical polarization thin film. The measurement component includes a polarizer 310, an analyzer 320, and an optical detection unit 330. The polarizer 310 is used to convert the light emitted by the light source module 100 into polarized light and adjust the polarization direction of the polarized light. The analyzer 320 is used to transmit polarized light with a specific polarization direction. The optical detection unit 330 can be used for spectral analysis of light. The sample to be measured 101 can be a wafer.

[0074] Specifically, the polarizer 310 is disposed between the light source module 100 and the sample to be measured 101, and the analyzer 320 is disposed between the optical detection unit 330 and the sample to be measured 101. The light emitted by the light source module 100 passes through the polarizer 310 and the objective lens and then irradiates the sample to be measured 101. The light reflected by the sample to be measured 101 enters the analyzer 320 through the objective lens. The light passing through the analyzer 320 enters the optical detection unit 330 during the measurement process. The objective lens can be a transmission objective lens or a reflection objective lens.

[0075] Considering that it is necessary to find the beam focus before measuring the thickness of the elliptical polarization thin film, the focusing component includes a beam splitter 210, a first mirror 220, and a differential detector. The differential detector includes a first detection element 231 and a second detection element 232. The beam splitter 210 is used to divide a beam of light into two beams of light. The first mirror 220 is used to reflect the light split by the beam splitter 210. The first detection element 231 and the second detection element 232 are used to detect the light split by the beam splitter 210 respectively. For example, the first detection element 231 and the second detection element 232 can be Charge-Coupled Devices (CCDs). The first detection element 231 and the second detection element 232 are the same detection elements.

[0076] Specifically, during the focusing process, the beam splitter 210 is disposed between the analyzer 320 and the optical detection unit 330, that is, the beam splitter 210 is located in the optical path of the light reflected by the sample to be measured 101, and the reflecting surfaces of the first mirror 220 and the beam splitter 210 are parallel. After the light passing through the analyzer 320 passes through the beam splitter 210, it is split into a first light beam and a second light beam by the beam splitter 210. The first light beam is a transmitted light beam, and the second light beam is a reflected light beam. The first light beam enters the first detection element 231, and the second light beam is reflected by the first mirror 220 to the second detection element 232.

[0077] Considering that the light passing through the beam splitter 210 will introduce chromatic dispersion, neither the first light beam nor the second light beam split by the beam splitter 210 during the focusing process enters the optical detection unit 330, that is, no light enters the optical detection unit 330 during the focusing process, and there is no need to start the measurement process, realizing the separation of the focusing process and the measurement process, and avoiding the influence of the beam splitter 210 used in the focusing process on the measurement process.

[0078] After the first detection element captures the first light ray and the second detection element captures the second light ray, a first detection result and a second detection result are obtained respectively. The control device can acquire the first detection result and the second detection result, and calculate the focusing position of the light ray emitted by the light source module based on the first detection result and the second detection result.

[0079] That is to say, the beam splitter divides the light ray reflected by the sample to be measured into a first light ray and a second light ray, that is, the beam splitter divides a beam of light ray reflected by the sample to be measured into two light rays. The first light ray is incident on the first detection element, and the second light ray is reflected by the first mirror to the second detection element. That is, two detection elements are used to capture the two light rays separated by the beam splitter respectively, and the detection results of the two light rays incident on the two detection elements are obtained respectively. Each detection result can reflect the focusing state of the sample to be measured. When the two detection results are combined for differential analysis, the analysis accuracy of the focusing state of the sample to be measured can be improved. Therefore, the control device can improve the accuracy of the calculated focusing position of the light ray emitted by the light source module based on the first detection result of the first detection element and the second detection result of the second detection element, and simultaneously obtain the detection results of the focusing state of the sample to be measured by using the beam splitter, the first detection element and the second detection element, so as to realize the determination of the focusing position with high efficiency.

[0080] In some embodiments, the measurement assembly further includes a first compensator 340, a second compensator 350, a first objective lens 360, and a second objective lens 370, as shown in the reference Figure 2 figure. The first compensator 340 is disposed between the polarizer 310 and the sample to be measured 101, and the second compensator 350 is disposed between the analyzer 320 and the sample to be measured 101. The first objective lens 360 is disposed between the first compensator 340 and the sample to be measured 101, and the first objective lens 360 is used to focus the light ray onto the surface of the sample to be measured 101; the second objective lens 370 is disposed between the second compensator 350 and the sample to be measured 101, and the second objective lens 370 is used to convert the light ray reflected from the surface of the sample to be measured 101 into parallel light.

[0081] In other embodiments, the measurement system further includes a placement platform 102 for placing the sample to be measured 101, as shown in the reference Figure 2 figure. The placement platform 102 can move in three-dimensional directions, and during the movement of the placement platform 102, the sample to be measured 101 can be driven to move in three-dimensional directions as well. The control device can control the movement of the placement platform 102, such as controlling the movement direction and movement speed of the placement platform 102, so as to move the sample to be measured 101 to the focusing position and achieve precise focusing.

[0082] In an embodiment of the present application, based on the rectilinear propagation of light, the second light ray, which is the reflected light ray split by the beam splitter 210, is reflected by the first mirror 220 to the second detection element 232. The first light ray, which is the transmitted light ray split by the beam splitter 210, can directly enter the first detection element 231 or can be reflected by other elements and then enter the first detection element 231. The following is a specific introduction.

[0083] In the first possible implementation manner, the first light ray can directly or indirectly enter the first detection element 231. Similarly, the second light ray can also directly or indirectly enter the second detection element 232. For the solution where the first light ray directly enters the first detection element 231, no other elements are provided in the light path between the beam splitter 210 and the first detection element 231. The light ray reflected by the sample to be measured 101 and passing through the analyzer 320 directly enters the first detection element 231 after passing through the beam splitter 210, thereby reducing the difficulty of the optical path arrangement of the focusing component.

[0084] Refer to Figure 3 As shown, the light ray reflected by the sample to be measured 101 and passing through the analyzer 320 enters the beam splitter 210. The beam splitter 210 splits the light ray reflected by the sample to be measured 101 and passing through the analyzer 320 into a first light ray and a second light ray. The first light ray directly enters the first detection element 231, and the second light ray is reflected by the first mirror 220 and then enters the second detection element 232.

[0085] In practical applications, when the detection directions of the first detection element 231 and the second detection element 232 are opposite, the moving direction of the light spot when the first light ray enters the first detection element 231 is opposite to the moving direction of the light spot when the second light ray enters the second detection element 232, achieving the optical path setting goal that the second light ray has a moving direction opposite to that of the first light ray, and improving the sensitivity of differential analysis using the first detection result and the second detection result.

[0086] In the second possible implementation manner, the first light ray can directly or indirectly enter the first detection element 231. Similarly, the second light ray can also directly or indirectly enter the second detection element 232. For the solution where the first light ray indirectly enters the first detection element 231, the focusing component further includes a second mirror 240. The second mirror 240 is disposed between the beam splitter 210 and the optical detection unit 330. The first light ray directly or indirectly enters the first detection element 231 through the second mirror 240 and the beam splitter 210.

[0087] For the solution where the first light is indirectly incident on the first detection element 231 through the second reflector 240 and the beam splitter 210, the focusing assembly further includes a third reflector 250. After the first light is reflected by the first reflector 220, it is continuously reflected by the beam splitter 210 and then reflected by the third reflector 250 to the first detection element 231. The reflecting surfaces of the third reflector 250 and the first reflector 220 are perpendicular to each other, that is, the third reflector 250 and the first reflector 220 are oppositely arranged and the placement angles are perpendicular to each other. At this time, the first light can be incident on the first detection element 231 through the reflections of 2 reflectors and the beam splitter 210, so as to achieve the goal of the optical path setting where the second light has the opposite moving direction to that of the first light, and improve the sensitivity of differential analysis using the first detection result and the second detection result.

[0088] Specifically, the first light is reflected back to the beam splitter 210 by the second reflector 240. The reflection direction of the first light reflected back to the beam splitter 210 is parallel to the incident direction of the first light incident on the second reflector 240. The beam splitter 210 is used to reflect the first light to the third reflector 250 again, and the third reflector 250 is used to incident the first light on the first detection element 231.

[0089] Reference Figure 4 As shown, the light passing through the analyzer 320 and reflected by the sample to be measured 101 is incident on the beam splitter 210. The beam splitter 210 splits the light passing through the analyzer 320 and reflected by the sample to be measured 101 into the first light and the second light. The second light is reflected by the first reflector 220 and then incident on the second detection element 232. The first light is reflected back to the beam splitter 210 by the second reflector 240. The beam splitter 210 reflects the first light to the third reflector 250. At this time, the propagation directions of the second light and the first light reflected by the beam splitter 210 to the first reflector 220 and the third reflector 250 are parallel and opposite, and the angle between them is 180 degrees. The first light is reflected by the third reflector 250 to the first detection element 231.

[0090] Based on the linear propagation of light, after the first light is reflected by 2 reflectors and the beam splitter 210, the moving direction of the light spot where the first light is incident on the first detection element 231 is opposite to the moving direction of the light spot where the second light is incident on the second detection element 232. Reference Figure 4As shown, when the light reflected by the sample 101 to be measured passing through the analyzer 320 moves upward from the position of the long dashed line to the position of the long and short dashed lines, the moving direction of the light spot of the first light ray incident on the first detection element 231 is downward, and the moving direction of the light spot of the second light ray incident on the second detection element 232 is upward, and the moving directions of the two are opposite. That is to say, when the sample 101 to be measured moves relative to the focusing position, the light spots on the first detection element 231 and the second detection element 232 will move in opposite directions. By simultaneously performing differential analysis on the detection results of the first detection element 231 and the second detection element 232, the sensitivity of the focusing assembly to the movement measurement of the sample 101 to be measured can be improved, the focusing accuracy can be improved, and further the measurement accuracy of the elliptical polarization film thickness can be improved.

[0091] In an embodiment of the present application, when the control device can obtain the first detection result of the first detection element 231 and the second detection result of the second detection element 232 and perform differential analysis based on the first detection result and the second detection result to determine the focusing position, the pixel origin position of the detection image obtained by the first detection element 231 and the pixel origin position of the detection image obtained by the second detection element 232 can be predefined in advance, and the corresponding relationship between the total offset of the light spot relative to the pixel origin position and the sample position movement amount can be constructed in advance, where the pixel origin position of the detection image corresponds to the focusing position of the light ray, and the total offset of the light spot relative to the pixel origin position is obtained by combining the offset of the first light ray obtained by the first detection element 231 relative to the pixel origin position and the offset of the second light ray obtained by the second detection element 232 relative to the pixel origin position, and the sample position movement amount is the movement amount of the sample 101 to be measured relative to the focusing position. Thus, subsequently, based on the first detection result being the first offset of the light spot relative to the pixel origin position when the first light ray is incident on the first detection element 231, and the second detection result being the second offset of the light spot relative to the pixel origin position when the second light ray is incident on the second detection element 232, the control device can directly calculate the focusing position of the light ray emitted by the light source module 100 according to the first offset, the second offset, and the corresponding relationship between the total offset and the sample position movement amount, realizing efficient and rapid calculation of the focusing position.

[0092] Specifically, when the first detection result is the first offset of the light spot relative to the pixel origin position when the first light ray is incident on the first detection element 231, and the second detection result is the second offset of the light spot relative to the pixel origin position when the second light ray is incident on the second detection element 232, the control device can first calculate the current total offset based on the first offset and the second offset, then determine the current sample position movement amount of the sample to be measured by using the corresponding relationship between the total offset and the sample position movement amount, and finally calculate the focusing position of the light ray emitted by the light source module 100 based on the sample position movement amount.

[0093] As a possible implementation, when the first light beam directly impinges on the first detection element 231, and the detection directions of the first detection element 231 and the second detection element 232 are the same, that is, when the first light beam impinges on the first detection element 231, the moving direction of the first offset of the light spot relative to the pixel origin position is the same as the moving direction of the second offset of the light spot relative to the pixel origin position when the second light beam impinges on the second detection element 232, the average value of the first offset and the second offset can be used as the total offset, thereby improving the accuracy of the focusing position calculation.

[0094] As another possible implementation, when the first light beam directly impinges on the first detection element 231, and the detection directions of the first detection element 231 and the second detection element 232 are opposite, or when the first light beam is reflected by two reflectors and the beam splitter 210 and then impinges on the first detection element 231, the moving direction of the first offset of the light spot relative to the pixel origin position when the first light beam impinges on the first detection element 231 is opposite to the moving direction of the second offset of the light spot relative to the pixel origin position when the second light beam impinges on the second detection element 232. The sum of the absolute value of the first offset and the absolute value of the second offset can be used as the total offset, thereby realizing the amplification of the moving amount of the light spot position, and further realizing the amplification of the movement of the sample to be measured 101, improving the sensitivity of the focusing component to measure the movement of the sample to be measured 101, and improving the focusing accuracy.

[0095] Accordingly, when the first light is indirectly incident on the first detection element 231 and the detection directions of the first detection element 231 and the second detection element 232 are the same, the average value of the first offset and the second offset can be used as the total offset; when the detection directions of the first detection element 231 and the second detection element 232 are opposite, the sum of the absolute values of the first offset and the second offset can be used as the total offset. Considering that after the control device obtains the total offset according to the first offset and the second offset, it calculates the sample position movement amount of the sample to be measured 101 relative to the focusing position according to the corresponding relationship between the total offset and the sample position movement amount. Therefore, pre-establishing the corresponding relationship between the total offset and the sample position movement amount can achieve fast and accurate determination of the focusing position. During the process of establishing the corresponding relationship between the total offset and the sample position movement amount, that is, in the calibration mode, when the sample to be measured 101 is in the focused state, the light reflected by the sample to be measured 101 and passing through the analyzer 320 is split by the beam splitter 210 into a third light and a fourth light. The third light is incident on the first detection element 231, and the fourth light is incident on the second detection element 232. The sample position movement amount of the sample to be measured 101, the third offset of the light spot relative to the pixel origin position when the third light is incident on the first detection element 231, and the fourth offset of the light spot relative to the pixel origin position when the fourth light is incident on the second detection element 232 are respectively obtained, and the sample position movement, the third offset, and the fourth offset correspond one by one; the total offset is calculated according to the third offset and the fourth offset. For example, if the offset directions of the third offset and the fourth offset are the same, the average value of the third offset and the fourth offset is used as the total offset; if the offset directions of the third offset and the fourth offset are different, the sum of the absolute values of the third offset and the fourth offset is used as the total offset; based on the fact that both the total offset and the sample position movement amount are known data, the corresponding relationship between the total offset and the sample position movement amount is established. During the actual focusing process, by identifying the offsets of the light spots of the first light and the second light relative to the pixel origin position in the first detection element 231 and the second detection element 232 respectively and substituting them into the corresponding relationship, the sample position movement amount of the sample to be measured 101 can be obtained. Subsequently, the control device controls the placement platform 102 to drive the sample to be measured 101 to move according to the sample position movement amount, so that the sample to be measured 101 can be located at the focusing position and the focusing process is completed.

[0096] As an example, taking the moving direction of the sample position as the z-axis direction in the three-dimensional direction, during the initial optical path debugging, the sample to be measured 101 is in the focused state. The positions of the first detection element 231 and the second detection element 232 are adjusted to make the number of pixels of the spot where the first light ray is incident on the first detection element 231 and the spot where the second light ray is incident on the second detection element 232 the same on the pixel images of the first detection element 231 and the second detection element 232. This number of pixels is defined as the pixel origin position, and the coordinate number is defined as 0. The sample to be measured 101 moves along the z-axis relative to the focused position, and the sample position movement amount of the sample to be measured 101 relative to the focused position is recorded as z1. At the same time, at each z1, the offset amounts of the spots on the first detection element 231 and the second detection element 232 are recorded as p1 and p2, and the absolute values of p1 and p2 are equal. When performing a first-order fit of p1 and p2 with respect to z1, assuming the fitting slope is k, since the defined pixel number at the focused position is 0, the fitting intercept is 0, and the formulas for the corresponding relationship between each detection element and the sample position movement amount are p1 = kz1 and p2 = kz1; when using differential detection with the first detection element 231 and the second detection element 232, the offset amount of the spot on the first detection element 231 is +p, and the offset amount of the spot on the second detection element 232 is -p, and the total offset amount is , and at this time, the formula for the corresponding relationship between the total offset amount and the sample position movement amount is p = 2kz1. By means of differential detection, the sensitivity of measuring the defocus amount of the sample to be measured 101 is increased.

[0097] In the embodiment of the present application, when the control device performs differential analysis based on the first detection result and the second detection result to determine the focused position, the corresponding relationship between the first position point where the first light ray is incident on the first detection element 231 and the position of the sample to be measured 101 and the corresponding relationship between the second position point where the second light ray is incident on the second detection element 232 and the position of the sample to be measured 101 can be respectively constructed in advance. In this way, subsequently, based on the first position point and the second position point obtained by the control device, the control device can directly calculate the focused position of the light ray emitted by the light source module according to the first position point, the second position point, the corresponding relationship between the first position point and the position of the sample to be measured 101, and the corresponding relationship between the second position point and the position of the sample to be measured 101, realizing efficient and fast calculation of the focused position.

[0098] Specifically, when the first detection result is the first position point of the light spot when the first light ray is incident on the first detection element, and the second detection result is the second position point of the light spot when the second light ray is incident on the second detection element, the control device can calculate the focusing position corresponding to the first light ray and the focusing position corresponding to the second light ray respectively according to the first position point, the second position point, the corresponding relationship between the first position point and the position of the sample to be measured 101, and the corresponding relationship between the second position point and the position of the sample to be measured 101, and can use the average value of the two as the focusing position of the light ray emitted by the light source module 100.

[0099] As an example, taking the moving direction of the sample position as the z-axis direction in the three-dimensional direction, during the initial debugging of the optical path, the sample to be measured 101 is in the focused state. The sample to be measured 101 moves relative to the focused position in the z-axis, records the position of the sample to be measured 101 as z2, and at the same time records the positions of the light spots on the first detection element 231 and the second detection element 232 as p3 and p4 at each z2. When performing a first-order fit of p3 and p4 with respect to z2, assuming the fitting slope is k, the fitting intercept b is the focused position.

[0100] In the embodiments of the present application, considering that during the focusing process, the beam splitter 210 is used for beam splitting to achieve differential detection, and the beam splitter 210 will introduce chromatic aberration and aberration during the measurement process, the beam splitter 210 can be set only during the focusing process and not during the measurement process, so as to achieve that neither the first light ray nor the second light ray is incident on the optical detection unit 330 during the focusing process. When the beam splitter 210 deviates from the light ray reflected by the sample to be measured during the measurement process, the light ray reflected by the sample to be measured is incident on the optical detection unit 330 to avoid the chromatic aberration and aberration introduced by the beam splitter 210. Specifically, the beam splitter 210 can be set on the moving platform. During the focusing process, the moving platform is used to set the beam splitter 210 in the optical path, and during the measurement process, the moving platform is used to move the beam splitter 210 out of the optical path, thereby avoiding the chromatic aberration and aberration introduced by the beam splitter 210 during the measurement process and improving the measurement accuracy.

[0101] The first possible implementation method is that the focusing component further includes a first moving platform 260, and the beam splitter 210 and the first detection element 231 are arranged on the first moving platform 260. The first moving platform 260 is used to drive the beam splitter 210 and the first detection element 231 to move into or out of the optical path of the light ray reflected by the sample to be measured 101 respectively or jointly. That is to say, before the measurement, the first moving platform 260 can move the beam splitter 210 and the first detection element 231 out of the optical path. Correspondingly, before the focusing, the first moving platform 260 can also move the beam splitter 210 and the first detection element 231 into the optical path.

[0102] As a possible implementation, the beam splitter 210 and the first detection element 231 can be jointly disposed on the first moving platform 260, and the first moving platform 260 drives the beam splitter 210 and the first detection element 231 to move together as a whole, thereby improving the moving efficiency. Refer to Figure 3 as shown.

[0103] As another possible implementation, the first moving platform 260 includes a first sub-moving platform and a second sub-moving platform. The beam splitter 210 is disposed on the first sub-moving platform, and the first detection element 231 is disposed on the second sub-moving platform, that is, the beam splitter 210 and the first detection element 231 are disposed on two separated platforms. The first sub-moving platform is used to drive the beam splitter 210 to move into or out of the optical path of the light reflected by the sample 101 to be measured, and the second sub-moving platform is used to drive the first detection element 231 to move into or out of the optical path of the light reflected by the sample 101 to be measured. That is, the first sub-moving platform and the second sub-moving platform are respectively used to drive the beam splitter 210 and the first detection element 231 out of the optical path, thereby realizing the separate control of the beam splitter 210 and the first detection element 231.

[0104] The second possible implementation is that the focusing assembly further includes a second moving platform 270. The beam splitter 210 and the second reflecting mirror 240 are disposed on the second moving platform 270, and the second moving platform 270 is used to drive the beam splitter 210 and the second reflecting mirror 240 to move into or out of the optical path of the light reflected by the sample 101 to be measured separately or jointly. That is to say, before measurement, the second moving platform 270 can move the beam splitter 210 and the second reflecting mirror 240 out of the optical path. Correspondingly, before focusing, the second moving platform 270 can also move the beam splitter 210 and the second reflecting mirror 240 into the optical path.

[0105] Specifically, the second moving platform 270 has a first surface and a second surface. The beam splitter 210 and the second reflecting mirror 240 can be disposed on the first surface, and the third reflecting mirror 250 and the second detection element 232 can be located on one side of the second surface.

[0106] As a possible implementation, the beam splitter 210 and the second reflecting mirror 240 can be jointly disposed on the second moving platform 270, and the second moving platform 270 drives the beam splitter 210 and the second reflecting mirror 240 to move together as a whole, thereby improving the moving efficiency. Refer to Figure 4 as shown.

[0107] Since the beam splitter 210 and the third mirror 250 are disposed on different sides of the second moving platform 270, in order to enable light to travel from the beam splitter 210 to the third mirror 250, an opening may be provided in the second moving platform 270, and this opening may allow light to pass through, thereby enabling the first light to be smoothly reflected from the beam splitter 210 to the third mirror 250. Refer to Figure 4 as shown.

[0108] As another possible implementation, the second moving platform 270 includes a third sub-moving platform 271 and a fourth sub-moving platform 272. The beam splitter 210 is disposed on the third sub-moving platform 271, and the second mirror 240 is disposed on the fourth sub-moving platform 272, that is, the beam splitter 210 and the second mirror 240 are disposed on two separated platforms. The third sub-moving platform 271 is configured to drive the beam splitter 210 to move into or out of the optical path of the light reflected by the sample to be measured 101, and the fourth sub-moving platform 272 is configured to drive the second mirror 240 to move into or out of the optical path of the light reflected by the sample to be measured 101, that is, the third sub-moving platform 271 and the fourth sub-moving platform 272 are respectively used to drive the beam splitter 210 and the second mirror 240 out of the optical path, thereby realizing the separate control of the beam splitter 210 and the second mirror 240.

[0109] Since the beam splitter 210 and the third mirror 250 are disposed on different sides of the second moving platform 270, in order to enable light to travel from the beam splitter 210 to the third mirror 250, there is a gap between the third sub-moving platform 271 and the fourth sub-moving platform 272, and this gap may allow light to pass through, thereby enabling the first light to be smoothly reflected from the beam splitter 210 to the third mirror 250. Refer to Figure 5 as shown.

[0110] In the embodiments of the present application, either the first moving platform 260 or the second moving platform 270 can be moved, thereby realizing the movement of the beam splitter 210 into and out of the optical path. The first moving platform 260 or the second moving platform 270 can perform rotational movement or translational movement, meeting various ways of moving the beam splitter 210 into and out of the optical path.

[0111] In the first possible implementation, the focusing component further includes a rotating motor. The first moving platform 260 or the second moving platform 270 can perform rotational movement based on the rotating motor, that is, the rotating motor is used to drive the first moving platform 260 or the second moving platform 270 to perform rotational movement. Among them, the rotation axis of the rotational movement is perpendicular to the surface of the first moving platform 260 or the second moving platform 270 and the propagation direction of the light reflected by the sample to be measured 101 and passing through the analyzer 320. The rotation axis can be located between the analyzer 320 and the beam splitter 210. The rotation direction of the rotational movement is the direction away from or close to the light reflected by the sample to be measured 101, so as to move the beam splitter 210 out of or into the optical path. Refer to Figures 3 - 5 as shown.

[0112] In the second possible implementation, the focusing component further includes a linear motor. The first moving platform 260 or the second moving platform 270 can perform translational movement based on the linear motor, that is, the linear motor is used to drive the first moving platform 260 or the second moving platform 270 to perform translational movement. Among them, the translation direction is the direction away from or close to the light reflected by the sample to be measured 101, so as to move the beam splitter 210 out of or into the optical path.

[0113] In the embodiments of the present application, both the first moving platform 260 or the second moving platform 270 can drive the beam splitter 210 to move into and out of the optical path. The control device can control the first moving platform 260 or the second moving platform 270 to move, so that during the measurement process, the beam splitter 210 moves out of the optical path, and the light reflected by the sample to be measured 101 and passing through the analyzer 320 is directly incident on the optical detection unit 330 without passing through the beam splitter 210. Refer to Figure 6 as shown. That is to say, the control device is used to control the first moving platform 260 or the second moving platform 270 to move, so that the beam splitter 210 moves into the optical path of the light reflected by the sample to be measured 101 or deviates from the light reflected by the sample to be measured 101.

[0114] Specifically, when the first moving platform 260 or the second moving platform 270 performs rotational movement, the control device can control the rotating motor to drive the first moving platform 260 or the second moving platform 270 to move the beam splitter 210 out of the optical path by using the rotating motor. When the first moving platform 260 or the second moving platform 270 performs translational movement, the control device can control the linear motor to drive the first moving platform 260 or the second moving platform 270 to move the beam splitter 210 out of the optical path by using the linear motor.

[0115] It can be seen that the measurement system provided by the embodiments of the present application avoids introducing the chromatic dispersion of the beam splitter during the measurement process by using the mobile platform to set the beam splitter, improving the measurement accuracy; during the focusing process, the beam splitter is used to split the light beam, and a differential detection scheme is adopted for the transmitted light and the reflected light, which can improve the sensitivity of focusing, thereby improving the focusing accuracy and measurement accuracy.

[0116] Based on the measurement system provided by the above embodiments, the embodiments of the present application further provide a measurement method. The measurement method provided by the embodiments of the present application can be applied to the measurement device provided by the above embodiments and can be specifically executed by the control device.

[0117] Refer to Figure 7 As shown in the flowchart of a measurement method provided by the embodiments of the present application, the method includes the following steps:

[0118] S701, control the light source module to emit light that passes through the polarizer and then irradiates the sample to be measured; control the beam splitter to move into the optical path of the reflected light of the sample to be measured. The light that passes through the analyzer and is reflected by the sample to be measured is divided into a first light beam and a second light beam by the beam splitter. The first light beam is incident on the first detection element, and the second light beam is reflected by the second mirror and then incident on the second detection element.

[0119] In the embodiments of the present application, during the focusing process, the control device can control the light source module to emit light that passes through the polarizer and then irradiates the sample to be measured; the control device can control the beam splitter to move into the optical path of the reflected light of the sample to be measured. At this time, the light that passes through the analyzer and is reflected by the sample to be measured is divided into a first light beam and a second light beam by the beam splitter. The first light beam is incident on the first detection element, and the second light beam is reflected by the second mirror and then incident on the second detection element.

[0120] S702, obtain the first detection result of the first detection element and the second detection result of the second detection element.

[0121] In the embodiments of the present application, after the first light beam is incident on the first detection element and the second light beam is reflected by the second mirror and then incident on the second detection element, the first detection element generates a first detection result based on the light spot obtained by the incidence of the first light beam, and the second detection element generates a second detection result based on the light spot obtained by the incidence of the second light beam. The control device can obtain the first detection result and the second detection result.

[0122] S703, calculate the focusing position of the light beam emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element.

[0123] In the embodiments of the present application, after the control device obtains the first detection result and the second detection result, it can calculate the focusing position of the light beam emitted by the light source module according to the first detection result and the second detection result.

[0124] In some embodiments, when the first detection result is the first offset of the light spot relative to the pixel origin when the first light ray is incident on the first detection element, and the second detection result is the second offset of the light spot relative to the pixel origin when the second light ray is incident on the second detection element, the control device may first calculate the current total offset based on the first offset and the second offset, then determine the current sample position movement amount of the sample to be measured by using the corresponding relationship between the total offset and the sample position movement amount, and finally calculate the focusing position of the light ray emitted by the light source module based on the sample position movement amount.

[0125] Considering that after the control device obtains the total offset according to the first offset and the second offset, it calculates the sample position movement amount of the sample to be measured relative to the focusing position according to the corresponding relationship between the total offset and the sample position movement amount. Therefore, pre-constructing the corresponding relationship between the total offset and the sample position movement amount can achieve fast and accurate determination of the focusing position. In the process of constructing the corresponding relationship between the total offset and the sample position movement amount, that is, in the calibration mode, when the sample to be measured is in the focused state, the light ray reflected by the sample to be measured and passing through the analyzer is split into a third light ray and a fourth light ray by the beam splitter. The third light ray is incident on the first detection element, and the fourth light ray is incident on the second detection element. The sample position movement amount of the sample to be measured, the third offset of the light spot relative to the pixel origin when the third light ray is incident on the first detection element, and the fourth offset of the light spot relative to the pixel origin when the fourth light ray is incident on the second detection element are respectively obtained, and the sample position movement, the third offset, and the fourth offset correspond one by one; the total offset is calculated according to the third offset and the fourth offset. For example, if the offset directions of the third offset and the fourth offset are the same, the average value of the third offset and the fourth offset is used as the total offset; if the offset directions of the third offset and the fourth offset are different, the sum of the absolute values of the third offset and the fourth offset is used as the total offset; the corresponding relationship between the total offset and the sample position movement amount is constructed according to the total offset and the sample position movement amount. Based on the fact that both the total offset and the sample position movement amount are known data, the corresponding relationship between the total offset and the sample position movement amount is constructed.

[0126] S704, control the beam splitter to move away from the light ray reflected by the sample to be measured so that the light ray reflected by the sample to be measured is incident on the optical detection unit.

[0127] In an embodiment of the present application, the control device can also control the first mobile platform or the second mobile platform to move, so that during the measurement process, the beam splitter is controlled to move away from the light reflected by the sample to be measured, so that the light reflected by the sample to be measured is incident on the optical detection unit, that is, during the measurement process, the beam splitter moves out of the optical path, and the light reflected by the sample to be measured and passing through the analyzer does not pass through the beam splitter and is directly incident on the optical detection unit, thereby avoiding the beam splitter introducing chromatic dispersion and aberration during the measurement process and improving the measurement accuracy.

[0128] The embodiment of the present application also provides a computer storage medium for storing a computer program. When the computer program runs on a computer device, the computer program is used to execute any one of the methods in the foregoing various embodiments.

[0129] In the context of the present application, the computer storage medium can be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0130] It should be noted that the computer-readable medium in the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device. In the present application, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and the computer-readable signal medium can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted by any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0131] When introducing the elements of various embodiments of the present application, the articles "a", "an", "the" and "said" are all intended to mean that there is one or more elements. The terms "comprising", "including" and "having" are all inclusive and mean that there may be other elements in addition to the listed elements.

[0132] It should be noted that those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The said program can be stored in a computer-readable storage medium. When the program is executed, it may include the processes of the above method embodiments. Among them, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0133] Each embodiment in this specification is described in a progressive manner. For the same or similar parts between the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the method embodiments, since they are basically similar to the system embodiments, they are described relatively simply. For the relevant parts, reference can be made to the description of the system embodiments.

[0134] The above is only the preferred embodiment of the present application. Although the present application has been disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the protection of the technical solution of the present application.

Claims

1. A measurement system, characterized in that, Including: A light source module, a focusing component, a measuring component, and a control device; the focusing component includes a beam splitter, a first reflector, and a differential detector, and the differential detector includes a first detection element and a second detection element; the measuring component includes a polarizer, an analyzer, and an optical detection unit; the measuring system further includes a moving platform, the beam splitter is arranged on the moving platform, and the moving platform is used to drive the beam splitter to move into the optical path of the reflected light of the sample to be measured during the focusing process, and move the beam splitter out of the optical path of the reflected light of the sample to be measured by using the moving platform during the measurement process; The light source module is used to emit light, and the light irradiates the sample to be measured after passing through the polarizer; When the beam splitter is located in the optical path of the reflected light of the sample to be measured, it is used to divide the light reflected by the sample to be measured and passing through the analyzer into a first light beam and a second light beam; The first light beam is incident on the first detection element; The second light beam is reflected by the first reflector to the second detection element; The control device is used to calculate the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element; When the beam splitter deviates from the reflected light of the sample to be measured, the reflected light of the sample to be measured is incident on the optical detection unit.

2. The system according to claim 1, wherein The focusing component further includes: a second reflector and a third reflector; The first light beam is reflected back to the beam splitter by the second reflector, the beam splitter is used to reflect the first light beam to the third reflector again, and the third reflector is used to make the first light beam incident on the first detection element.

3. The system according to claim 1, characterized in that, The first detection result is the first offset of the light spot compared to the pixel origin position when the first light beam is incident on the first detection element, and the second detection result is the second offset of the light spot compared to the pixel origin position when the second light beam is incident on the second detection element; The control device is used to calculate the focusing position of the light emitted by the light source module according to the corresponding relationship between the first offset, the second offset, the total offset, and the sample position movement amount, and the total offset is calculated according to the first offset and the second offset.

4. The system according to claim 3, characterized in that, The system further includes a calibration mode. In the calibration mode, the beam splitter is located in the optical path of the reflected light of the sample to be measured, and is used to divide the light reflected by the sample to be measured and passing through the analyzer into a third light beam and a fourth light beam; The control device is used to obtain the sample position movement amount, the third offset of the light spot compared to the pixel origin position when the third light beam is incident on the first detection element, and the fourth offset of the light spot compared to the pixel origin position when the fourth light beam is incident on the second detection element; The control device is used to calculate the total offset according to the third offset and the fourth offset; The control device is used to construct the corresponding relationship between the total offset and the sample position movement amount according to the total offset and the sample position movement amount.

5. The system according to claim 1, wherein The first detection result is the first position point of the light spot when the first light ray is incident on the first detection element, and the second detection result is the second position point of the light spot when the second light ray is incident on the second detection element; The control device is configured to calculate the focusing position of the light ray emitted by the light source module according to the correspondence between the first position point, the second position point, the first position point and the position of the sample to be measured, and the correspondence between the second position point and the position of the sample to be measured.

6. The system according to claim 1, wherein, It further includes: A first moving platform; The beam splitter and the first detection element are arranged on the first moving platform, and the first moving platform is used to drive the beam splitter and the first detection element to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured.

7. The system according to claim 6, wherein The first moving platform includes a first sub-moving platform and a second sub-moving platform; the beam splitter is arranged on the first sub-moving platform, and the first detection element is arranged on the second sub-moving platform; The first sub-moving platform is used to drive the beam splitter to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured; The second sub-moving platform is used to drive the first detection element to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured.

8. The system according to claim 2, characterized in that, It further includes: a second moving platform; The beam splitter and the second reflector are arranged on the second moving platform, and the second moving platform is used to drive the beam splitter and the second reflector to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured.

9. The system according to claim 8, wherein The second moving platform includes a third sub-moving platform and a fourth sub-moving platform; the beam splitter is arranged on the third sub-moving platform, and the second reflector is arranged on the fourth sub-moving platform; The third sub-moving platform is used to drive the beam splitter to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured; The fourth sub-moving platform is used to drive the second reflector to move into the optical path of the light ray reflected by the sample to be measured or deviate from the light ray reflected by the sample to be measured.

10. The system according to claim 6 or 8, characterized in that, The focusing assembly further includes: a rotary motor; The rotary motor is used to drive the first moving platform or the second moving platform to perform a rotational movement, the rotation axis is perpendicular to the propagation direction of the light ray reflected by the sample to be measured passing through the analyzer, the rotation axis is located between the analyzer and the beam splitter, and the rotation direction is away from or close to the light ray reflected by the sample to be measured.

11. The system according to claim 6 or 8, characterized in that, The focusing assembly further includes: a linear motor; The linear motor is used to drive the first moving platform or the second moving platform to perform a translational movement, and the translational direction is away from or close to the light ray reflected by the sample to be measured.

12. The system according to claim 6 or 8, wherein The control device is configured to control the movement of the first moving platform or the second moving platform so that the beam splitter moves into the optical path of the light ray reflected by the sample to be measured or the beam splitter moves away from the light ray reflected by the sample to be measured.

13. The system according to any one of claims 1-9, characterized in that, The measurement system further includes: a placement platform; the placement platform is used to place the sample to be measured; The control device is used to control the movement of the placement platform to move the sample to be tested to the focusing position.

14. The system according to any one of claims 1-9, characterized in that The light source module emits a broadband light source, and the optical detection unit is a photodetector.

15. The system according to any one of claims 1-9, characterized in that, The measurement assembly further includes a first compensator, a second compensator, a first objective lens, and a second objective lens. The first compensator is disposed between the polarizer and the sample to be tested, the second compensator is disposed between the analyzer and the sample to be tested, the first objective lens is disposed between the first compensator and the sample to be tested, and the second objective lens is disposed between the second compensator and the sample to be tested.

16. A measurement method, characterized in that, Comprising: Controlling the light source module to emit light, which is irradiated on the sample to be tested after passing through the polarizer; controlling the beam splitter to move into the optical path of the light reflected by the sample to be tested, and the light reflected by the sample to be tested and passing through the analyzer is divided into a first light beam and a second light beam by the beam splitter; the first light beam is incident on the first detection element; The second light beam is reflected by the second mirror to the second detection element; Obtaining a first detection result of the first detection element and a second detection result of the second detection element; Calculating the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element; Controlling the beam splitter to move away from the light reflected by the sample to be tested, so that the light reflected by the sample to be tested is incident on the optical detection unit; The beam splitter is disposed on a moving platform, and the moving platform is used to drive the beam splitter to move into the optical path of the light reflected by the sample to be tested during the focusing process, and to move the beam splitter out of the optical path of the light reflected by the sample to be tested during the measurement process.

17. The method according to claim 16, wherein The first detection result is a first offset of the light spot with respect to the pixel origin position when the first light beam is incident on the first detection element, and the second detection result is a second offset of the light spot with respect to the pixel origin position when the second light beam is incident on the second detection element; The calculating the focusing position of the light emitted by the light source module according to the first detection result of the first detection element and the second detection result of the second detection element includes: Calculating the focusing position of the light emitted by the light source module according to the corresponding relationship between the first offset, the second offset, the total offset, and the sample position movement amount, and the total offset is calculated according to the first offset and the second offset.

18. The method according to claim 17, wherein, It further includes a calibration mode. In the calibration mode, the beam splitter is located in the optical path of the light reflected by the sample to be tested and is used to divide the light reflected by the sample to be tested and passing through the analyzer into a third light beam and a fourth light beam; the method further includes: Obtaining the sample position movement amount, a third offset of the light spot with respect to the pixel origin position when the third light beam divided by the beam splitter is incident on the first detection element, and a fourth offset of the light spot with respect to the pixel origin position when the fourth light beam divided by the beam splitter is incident on the second detection element; Calculating the total offset according to the third offset and the fourth offset; Constructing the corresponding relationship between the total offset and the sample position movement amount according to the total offset and the sample position movement amount.

19. A computer storage medium, characterized in that, The computer storage medium is used to store a computer program, which, when running on a computer device, causes the computer device to execute the method according to any one of claims 16-18.

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