Measurement systems and methods

Abstract

This disclosure provides a measurement system and method, relating to the field of measurement technology. The measurement system includes: a light source configured to generate an original light beam, wherein the original light beam returning from a measured area of ​​a measured object is a returned light beam; an optical component configured to obtain a beam to be processed based on the returned light beam, wherein at least a portion of the beam to be processed is a first light beam; a first detection device configured to obtain first detection information based on the first light beam; a mobile device configured to move the optical component relative to the measured object along the optical axis of the optical component; and a processing system configured to determine, based on the first detection information at each of a plurality of first moments, the actual distance between the optical component and a fixed plane of the measured object at each first moment.

Description

Technical Field

[0001] This disclosure relates to the field of measurement technology, and more particularly to a measurement system and method. Background Technology

[0002] In the field of integrated circuit manufacturing, to improve product yield, it is necessary to measure the three-dimensional morphology of wafers to check whether the wafer manufacturing process meets standards. Three-dimensional morphology measurement based on white light interferometry is widely used in integrated circuit inspection due to its non-contact, fast, and high-precision characteristics.

[0003] White light interferometry uses white light with a very short coherence length as a light source, and the surface morphology of the object being measured can be located by the peak value of the interference signal intensity. Summary of the Invention

[0004] According to one aspect of the present disclosure, a measurement system is provided, comprising: a light source configured to generate an original light beam, wherein the original light beam returning from a measured region of an object being measured forms a returned light beam; an optical component configured to obtain a beam to be processed based on the returned light beam, wherein at least a portion of the beam to be processed is a first light beam; a first detection device configured to obtain first detection information based on the first light beam; a mobile device configured to move the optical component relative to the object being measured along the optical axis of the optical component; and a processing system configured to determine, based on the first detection information at each of a plurality of first moments, an actual distance between the optical component and a fixed plane of the object being measured at each of the first moments.

[0005] In some embodiments, the optical component includes: a first beam splitter configured to split the original beam into a reference beam and an object beam incident on the region under test, wherein the object beam returning from the region under test to the optical component forms the return beam; and a reference mirror configured to propagate the reference beam along a predetermined trajectory to obtain a pre-interference beam, wherein the pre-interference beam and the return beam interfere to obtain the beam to be processed; the first detection information includes the intensity of light of a predetermined wavelength in the beam to be processed.

[0006] In some embodiments, the processing system is configured to determine the actual distance between the optical component and a fixed plane of the object under test at each first moment, comprising: controlling the mobile device to move the optical component and the object under test relative to each other along the optical axis to achieve a plurality of predetermined distances between the optical component and the fixed plane at a plurality of second moments; acquiring the first detection information at each of the plurality of second moments; and determining the actual distance between the optical component and the fixed plane at each first moment based on the plurality of predetermined distances and the plurality of first detection information at each second moment.

[0007] In some embodiments, the processing system is configured to determine the actual distance between the optical component and the fixed plane at each first moment based on the plurality of predetermined distances and the plurality of first detection information at each second moment, comprising: performing linear processing on each of the plurality of predetermined distances to obtain a motion parameter; fitting a function to be fitted with the difference between the motion parameter and the parameter to be determined at each second moment as the independent variable and the first detection information at each second moment as the dependent variable to obtain a fitted function; and determining the actual distance between the optical component and the fixed plane at each first moment based on the fitted function and the first detection information at the plurality of first moments.

[0008] In some embodiments, the optical component includes: a first beam splitter configured to split the original beam into a reference beam and an object beam incident on the region under test, wherein the object beam returning from the region under test to the optical component forms the return beam; and a reference mirror configured to propagate the reference beam along a predetermined trajectory to obtain a pre-interference beam, wherein the pre-interference beam and the return beam interfere to obtain the beam to be processed; the first detection information includes the intensity of light of a predetermined wavelength in the beam to be processed; the function to be fitted is: I = A + cos r(x-x0)+B, where the linear processing includes multiplying by 2Π / λ, r=1; or, the linear processing includes multiplying by 1, r=2Π / λ, where λ is the wavelength of the predetermined wavelength light; the processing system is configured to fit a function to be fitted with the difference between the moving parameter and the parameter to be determined at each second time moment as the independent variable and the first detection information at each second time moment as the dependent variable, to obtain a fitted function including: using the moving parameter at each second time moment as x in the function to be fitted and the intensity of the predetermined wavelength light at each second time moment as I in the function to be fitted. Fitting the function to be fitted yields A, the parameter to be determined x0, and B, thereby obtaining the fitted function. Determining the actual distance between the optical component and the fixed plane at each first moment based on the fitted function and the first detection information at the plurality of first moments includes: using the intensity of light at the predetermined wavelength at each first moment as I in the fitted function, calculating x in the fitted function as the movement parameter at each first moment; and determining the actual distance between the optical component and the fixed plane at each first moment based on the movement parameter at each first moment.

[0009] In some embodiments, the reference mirror is configured to reflect the reference beam to propagate the reference beam along a preset trajectory to obtain a pre-interference beam; both the reference mirror and the first beam splitter are semi-transparent and semi-reflective mirrors, and the reference mirror and the first beam splitter are arranged in parallel; or, the reference mirror is a reflective mirror.

[0010] In some embodiments, the first detection device includes: one of a grating and a filter; and a light intensity detector.

[0011] In some embodiments, the measurement system further includes: a first aperture, configured to block a portion of the beam to be processed from entering the first detection device at an angle greater than a first preset angle between the beam and the central axis of the beam to be tested.

[0012] In some embodiments, the measurement system further includes: a second detection device configured to obtain second detection information based on a second beam, wherein the second beam is a portion of the returned beam or a portion of the beam to be processed, and the second detection information characterizes the relative distance between the optical component and the measured area in the optical axis direction of the optical component; the processing system is further configured to acquire a first moment when the second detection information is preset detection information as a characteristic moment; acquire the actual distance between the optical component and the fixed plane at the characteristic moment; and determine the height information of the measured area based on the actual distance between the optical component and the fixed plane at the characteristic moment.

[0013] In some embodiments, the second detection device is configured to obtain second detection information based on the second light beam by: obtaining a detection image based on the second light beam; and obtaining the second detection information based on the detection image, wherein the second detection information includes at least one of the light intensity of the second light beam and the contrast of the detection image.

[0014] In some embodiments, the measurement system further includes a second beam splitter configured to split the returned beam or the beam to be processed to obtain the second beam.

[0015] In some embodiments, the optical component further includes: a first lens configured to collect the returned beam, the first beam being formed by at least a portion of the returned beam collected by the first lens; or, the first lens configured to collect the beam to be processed, the first beam being formed by at least a portion of the beam to be processed collected by the first lens.

[0016] In some embodiments, when the first lens is configured to collect the returned beam, the second beam splitter is configured to split the returned beam collected by the first lens to form a second beam and a third beam, and the optical components are configured to obtain the beam to be processed based on the third beam; when the first lens is configured to collect the beam to be processed, the second beam splitter is configured to split the beam to be processed collected by the first lens to form the first beam and the second beam.

[0017] In some embodiments, the optical component further includes a second lens configured to collect the second light beam.

[0018] In some embodiments, the second beam splitter is configured to split the returned beam to obtain the second beam, and the second lens makes the central axis of the second beam parallel to the direction of movement of the optical component; the second beam splitter is fixedly connected to the optical component.

[0019] In some embodiments, the optical component is configured to move relative to the second beam splitter.

[0020] In some embodiments, the second beam splitter is configured to split the returned beam to obtain the second beam; the optical component includes a lens configured to collect the returned beam and propagate the returned beam to the second beam splitter, or the lens is configured to collect the second beam; the measurement system further includes a second aperture, configured to block a portion of the second beam at an angle greater than a second preset angle from entering the second detection device, wherein both the second aperture and the second detection device are conjugate to the focal plane of the lens.

[0021] In some embodiments, the original beam includes a first original beam and a second original beam; the light source includes: a first sub-light source configured to generate the first original beam and a second sub-light source configured to generate the second original beam; the returned beam includes a first returned beam and a second returned beam, the first returned beam being the first original beam returning from the measured region and the second returned beam being the second original beam returning from the measured region; the optical components include: a first optical component configured to form the beam to be processed based on the first returned beam, the first beam being the beam to be processed, and a second optical component configured to collect the second returned beam, the second beam being the second returned beam, the first optical component and the second optical component being fixedly connected.

[0022] In some embodiments, the first optical component is further configured to collect the first original beam and bring the first original beam to the region under test; the first optical component includes a dispersive prism configured to converge light of different wavelengths in the first original beam to different positions on the optical axis of the first optical component.

[0023] In some embodiments, the measurement system further includes: a data acquisition system configured to emit a synchronization trigger signal at each first moment; the first detection device configured to obtain the first detection information based on the first beam in response to the synchronization trigger signal; and the second detection device configured to obtain the second detection information based on the second beam in response to the synchronization trigger signal.

[0024] In some embodiments, the second detection information includes the light intensity of the second beam; the light intensity of the second beam at the characteristic time is greater than the light intensity of the second beam at any of the plurality of first times other than the characteristic time.

[0025] In some embodiments, the measured region includes at least one sub-region, the probe image includes at least one pixel corresponding to the at least one sub-region, each pixel is configured to acquire a second beam of light in a sub-region; the second probe information includes the light intensity of the second beam of light formed by each sub-region, wherein, at the characteristic time of any sub-region, the grayscale value of the pixel in that sub-region is greater than the grayscale value of that pixel at any of the plurality of first times other than the characteristic time; the processing system is configured to determine the height information of the measured region based on the actual distance between the optical component and the fixed plane at the characteristic time, including: determining the height information of the sub-region based on the actual distance between the optical component and the fixed plane at the characteristic time of each sub-region, thereby obtaining the height information of the measured region.

[0026] According to another aspect of the present disclosure, a measurement method is provided, comprising: a light source generating an original light beam, wherein the original light beam returning from a measured area of ​​a measured object is a returned light beam; an optical component obtaining a beam to be processed based on the returned light beam, at least a portion of the beam to be processed being a first light beam; obtaining first detection information based on the first light beam; moving the optical component relative to the measured object along the optical axis of the optical component; and determining, based on the first detection information at each of a plurality of first moments, the actual distance between the optical component and the fixed plane at each first moment.

[0027] In some embodiments, determining the actual distance between the optical component and the object under test at each first moment includes: moving the optical component and the object under test relative to each other along the optical axis to achieve a plurality of predetermined distances between the optical component and the fixed plane at a plurality of second moments; acquiring the first detection information at each of the plurality of second moments; and determining the actual distance between the optical component and the fixed plane at each first moment based on the plurality of predetermined distances and the plurality of first detection information at each second moment.

[0028] In some embodiments, determining the actual distance between the optical component and the fixed plane at each first moment based on the plurality of predetermined distances and the plurality of first detection information at each second moment includes: performing linear processing on each of the plurality of predetermined distances to obtain a motion parameter; fitting a fitting function to be fitted with the difference between the motion parameter and the parameter to be determined at each second moment as the independent variable and the first detection information at each second moment as the dependent variable to obtain a fitting function; and determining the actual distance between the optical component and the fixed plane at each first moment based on the fitting function and the first detection information at the plurality of first moments.

[0029] In some embodiments, the optical component includes a first beam splitter and a reflector, and the measurement method further includes: the first beam splitter splitting the original light beam into a reference beam and an object beam incident on the measured region, wherein the object beam returning from the measured region to the optical component is the return beam; and the reference mirror causing the reference beam to propagate along a preset trajectory to obtain a pre-interference beam, wherein the pre-interference beam and the return beam interfere to obtain the beam to be processed; the first detection information includes the intensity of light of a predetermined wavelength in the beam to be processed; the function to be fitted is: I = A + cos r(x-x0)+B, where the linear processing includes multiplying by 2Π / λ, r=1; or, the linear processing includes multiplying by 1, r=2Π / λ, where λ is the wavelength of the predetermined wavelength light; using the difference between the moving parameter and the parameter to be determined at each second time moment as the independent variable, and the first detection information at each second time moment as the dependent variable, the function to be fitted is fitted to obtain the fitting function, which includes: using the moving parameter at each second time moment as x in the function to be fitted, and the intensity of the predetermined wavelength light at each second time moment as I in the function to be fitted, the function to be fitted is fitted to the parameter to be fitted to the desired wavelength light. The fitting function is fitted to obtain A, the parameter to be determined x0, and B, thereby obtaining the fitting function; based on the fitting function and the first detection information at the plurality of first moments, determining the actual distance between the optical component and the fixed plane at each first moment includes: using the intensity of the light of the predetermined wavelength at each first moment as I in the fitting function, calculating x in the fitting function as the movement parameter at each first moment; and determining the actual distance between the optical component and the fixed plane at each first moment based on the movement parameter at each first moment.

[0030] In some embodiments, the measurement method further includes: obtaining second detection information based on a second beam, wherein the second beam is a portion of the returned beam or a portion of the beam to be processed, and the second detection information characterizes the relative position between the optical component and the measured area; obtaining a first moment when the second detection information is preset detection information as a characteristic moment; obtaining the actual distance between the optical component and the fixed plane at the characteristic moment; and determining the height information of the measured area based on the actual distance between the optical component and the fixed plane at the characteristic moment.

[0031] In some embodiments, obtaining second detection information based on the second beam includes: obtaining a detection image based on the second beam; and obtaining the second detection information based on the detection image, wherein the second detection information includes at least one of the light intensity of the second beam and the contrast of the detection image.

[0032] In some embodiments, the second detection information includes the light intensity of the second beam; the light intensity of the second beam at the characteristic time is greater than the light intensity of the second beam at any of the plurality of first times other than the characteristic time.

[0033] In some embodiments, the measurement method further includes: obtaining the shape of the object under test based on the height information of the plurality of measured regions relative to the same reference plane.

[0034] Other features, aspects, and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0035] The accompanying drawings form part of this specification, depicting exemplary embodiments of the present disclosure and, together with the specification, serving to explain the principles of the present disclosure. In the drawings:

[0036] Figure 1 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure;

[0037] Figure 2 This is a schematic diagram of the structure of a measurement system according to other embodiments of the present disclosure;

[0038] Figure 3 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure;

[0039] Figure 4 This is a flowchart illustrating the process of determining the actual distance between the optical component and the fixed plane of the object under test at each first moment, based on some implementation methods of this disclosure.

[0040] Figure 5 It shows Figure 4 A specific implementation of step 406 in the process;

[0041] Figure 6 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure;

[0042] Figure 7 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure;

[0043] Figure 8 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure;

[0044] Figure 9 This is a schematic flowchart of a measurement method according to some embodiments of the present disclosure;

[0045] Figure 10This is a schematic flowchart of a measurement method according to other embodiments of the present disclosure.

[0046] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components. Detailed Implementation

[0047] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0048] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "containing" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well. Terms such as "above" and "below" are used only to indicate relative positional relationships, and these relative positional relationships may also change accordingly when the absolute position of the described object changes.

[0049] In this disclosure, when a specific component is described as being located between a first component and a second component, an intermediary component may or may not be present between the specific component and the first or second component. When a specific component is described as connecting to other components, the specific component may be directly connected to the other components without having an intermediary component, or it may not be directly connected to the other components but may have an intermediary component.

[0050] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0051] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0052] The inventors noticed that when the optical component and the object being measured move relative to each other, due to factors such as movement errors, vibration of the measurement system, and environmental vibration, the desired predetermined distance between the optical component and the fixed plane of the object being measured often differs from the actual distance between them. Therefore, measuring the height of the object being measured based on the predetermined distance will lead to inaccurate measurement results.

[0053] In view of the above, the present disclosure provides the following technical solutions.

[0054] Figure 1 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure.

[0055] like Figure 1 As shown, the measurement system may include a light source 101, an optical component 102, a first detection device 103, a mobile device 104, and a processing system 105.

[0056] The light source 101 is configured to generate a raw light beam. In some embodiments, the raw light beam can be a broadband light beam, such as one or a combination of white light, infrared light, and ultraviolet light. Here, the raw light beam returning from the measured area of ​​the object under test A (e.g., a wafer) is called the return beam.

[0057] In some embodiments, the raw light beam generated by the light source 101 can be directly incident on the object A being measured. In other embodiments, see [link to other embodiments]. Figure 1 The original light beam generated by the light source 101 can be incident on the object A under test via the optical component 102. For example, the original light beam generated by the light source 101 can be shaped by the shaping lens group 201 and then incident on the beam splitter 202. After being reflected by the beam splitter 202, it can be incident on the optical component 102, and then incident on the object A under test via the optical component 102. For example, the shaping lens group 201 can perform collimation, filtering, and other shaping operations on the original light beam generated by the light source 101.

[0058] The optical component 102 is configured to obtain the beam to be processed based on the returned beam. Here, at least a portion of the beam to be processed is the first beam.

[0059] In some embodiments, optical component 102 may be an interference objective. In this case, the beam to be processed may be an interference beam. In other embodiments, optical component 102 may be a confocal objective. In this case, the beam to be processed may be a return beam returning from the object under test A. Optical component 102 is configured to split the original beam into a reference beam and an object beam incident on the region under test, wherein the object beam returning to the optical component from the region under test forms the return beam, and optical component 102 is further configured to cause interference between the reference beam and the return beam.

[0060] For example, optical component 102 includes a first beam splitter 112 and a reference mirror 122. The first beam splitter 112 is configured to split the original beam into a reference beam and an object beam incident on the test area of ​​the object A. The reference mirror 122 is configured to cause the reference beam to propagate along a preset trajectory to obtain a pre-interference beam, wherein the pre-interference beam and the return beam interfere to obtain the beam to be processed.

[0061] In one embodiment, the first beam splitter 112 is configured to split the original beam into a reference beam and an object beam incident on the test area of ​​the object A. Here, the object beam returning from the test area of ​​the object A to the optical assembly 102 is the return beam. The reference mirror 122 is configured to propagate the reference beam along a preset trajectory by reflecting the reference beam to obtain a pre-interference beam. Here, the pre-interference beam and the return beam interfere to obtain the beam to be processed. For example, both the reference mirror 122 and the first beam splitter 112 are semi-transparent and semi-reflective mirrors, and the reference mirror 122 and the first beam splitter 112 are arranged in parallel. However, the embodiments disclosed herein are not limited thereto. For example, in other embodiments, the reference mirror 122 may be a reflector (e.g., Figure 6 (Example shown).

[0062] In other embodiments, the reference mirror 122 is configured to refract or diffract the reference beam to obtain a pre-interference beam. For example, the reference mirror 122 is a refractive element or a diffracting element.

[0063] The first detection device 103 is configured to obtain first detection information based on the first light beam. In some embodiments, the light beam to be processed is an interference beam obtained by the interference of the reflected beam and the returned beam. In this case, the first detection information may include the intensity of light of a predetermined wavelength in the light beam to be processed. For example, the light beam to be processed includes light of multiple wavelengths. The predetermined wavelength of light may be any one of the multiple wavelengths of light.

[0064] The mobile device 104 is configured to move the optical component 102 relative to the object A under test along the optical axis of the optical component 102.

[0065] For example, under the control of the processing system 105, the mobile device 104 can move the optical component 102 relative to the object being measured A along the optical axis of the optical component 102. As another example, under the control of the processing system 105, the mobile device 104 can move the object being measured A relative to the optical component 102 along the optical axis of the optical component 102. Here, the optical axis of the optical component 102 can be understood as the direction of the central axis of the returning beam entering the optical component 102, for example... Figure 1 The direction indicated by the double-headed arrow in the diagram. In some embodiments, the mobile device 104 may be a phase shifter.

[0066] Movement along the optical axis of optical component 102 relative to the object under test A means that the movement direction of optical component 102 and the object under test A has a component along the optical axis of optical component 102, as long as the movement direction of optical component 102 and the object under test A is not perpendicular to the optical axis of optical component 102.

[0067] The processing system 105 is configured to determine the actual distance between the optical component 102 and the fixed plane of the object under test A at each of a plurality of first moments, based on the first detection information at each of the first moments. Here, the fixed plane of the object under test A can be a plane defined by any region of the surface of the object under test A. In other words, any plane of the object under test A can be used as the fixed plane of the object under test A.

[0068] It should be understood that the actual distance between the optical component 102 and the fixed plane of the object being measured A is different at different first moments. For example, the processing system 105 can subsequently determine the height information of the measured area based on the actual distance between the optical component 102 and the fixed plane of the object being measured A at each first moment.

[0069] The processing system 105 may be a computer or other device capable of processing. In some embodiments, the processing system 105 may include a memory and a processor coupled to the memory, the processor performing various operations based on instructions stored in the memory, such as determining the actual distance between the optical component 102 and a fixed plane of the object A being measured at each first moment, as well as operations mentioned later. The memory may include, for example, system memory, a fixed non-volatile storage medium, etc. The system memory may store, for example, an operating system, application programs, a boot loader, and other programs.

[0070] In the above embodiment, the optical component 102 obtains the beam to be processed based on the returned beam, and the first detection device 103 obtains first detection information based on at least a portion of the beam to be processed (i.e., the first beam). The processing system 105 determines the actual distance between the optical component 102 and the fixed plane of the object under test A at each of the multiple first moments based on the first detection information at each of the multiple first moments. In this way, the actual distance between the optical component 102 and the fixed plane of the object under test A at each of the multiple first moments can be obtained using the first detection information at each of the multiple first moments. Based on the actual distance between the optical component 102 and the fixed plane of the object under test A at each of the multiple first moments, subsequent operations can be performed more accurately, for example, the height information of the measured area of ​​the object under test A can be determined more accurately.

[0071] In some embodiments, see Figure 1The measurement system may also include a second detection device 106. The second detection device 106 is configured to obtain second detection information based on the second beam. Here, the second beam is a portion of the beam to be processed. For example, the measurement system also includes a second beam splitter 107, configured to split the beam to be processed to obtain a second beam. For example, the beam to be processed transmitted through the second beam splitter 107 is the first beam, and the beam to be processed reflected by the second beam splitter 107 is the second beam, or vice versa. In other embodiments, the second beam may be a portion of the returned beam. In this case, the second beam splitter 107 is configured to split the returned beam to obtain a second beam. Other embodiments (e.g., Figure 6 The following example will be used for illustration.

[0072] The second detection information can characterize the relative distance between the optical component 102 and the measured area of ​​the measured object A along the optical axis of the optical component. That is, the second detection information changes with the relative distance. The relative distance between the optical component 102 and the measured area of ​​the measured object A can be obtained based on the second detection information.

[0073] In some embodiments, the second detection device 106 can obtain a detection image (e.g., an interference image or an image of the measured area of ​​the object A) based on the second beam, and then obtain second detection information based on the detection image. The second detection device 106 may be, for example, a camera, a video camera, etc. In other embodiments, the second detection device 106 may be a single photodiode or a photomultiplier tube.

[0074] Here, the second detection information may include at least one of the light intensity of the second beam and the contrast of the detection image. For example, the second detection information may include the light intensity of the second beam. Another example is that the second detection information may include the contrast of the detection image obtained based on the second beam. Yet another example is that the second detection information may include both the light intensity of the second beam and the contrast of the detection image.

[0075] The processing system 105 is also configured to acquire the first moment when the second detection information is the preset detection information as the feature moment; acquire the actual distance between the optical component 102 and the fixed plane of the object A under test at the feature moment; and determine the height information of the measured area based on the actual distance between the optical component 102 and the fixed plane of the object A under test at the feature moment.

[0076] In some embodiments, the second detection information may include the light intensity of the second beam. The light intensity of the second beam at the characteristic moment is greater than the light intensity of the second beam at any of the plurality of first moments other than the characteristic moment. In other words, the light intensity of the second beam is maximum at the characteristic moment. For example, at the characteristic moment, the optical path length of the reference beam is equal to the optical path length of the object beam. Another example is that at the characteristic moment, the distance between the optical component 102 and the measured area of ​​the measured object A is equal to the focal length of the optical component 102.

[0077] For different measured areas, the distance between the optical component 102 and the measured area is the same at the characteristic time. Therefore, the actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time can reflect the height of the measured area. For example, for measured area A1, the actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time is h1; for measured area A2, the actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time is h2. The difference between h1 and h2 is the height difference between measured area A1 and measured area A2.

[0078] In some embodiments, the measured region includes at least one sub-region, and the probe image includes at least one pixel corresponding to the at least one sub-region. For example, the measured region includes multiple sub-regions, and the probe image includes multiple pixels corresponding one-to-one with the multiple sub-regions. The second probe information may include the light intensity of the second beam acquired by each pixel. In this case, the preset probe information is the maximum grayscale value of the pixel. The feature time is the first time when the grayscale value is the largest. Each pixel has a feature time, that is, each sub-region corresponds to a feature time. At the feature time of each sub-region, the grayscale value of the pixel corresponding to that sub-region is greater than the grayscale value of that pixel at any of the multiple first times other than the feature time. In other words, for a certain pixel, the grayscale value of that pixel is the largest at the feature time.

[0079] In other embodiments, the preset detection information is the value when the mean or sum of the grayscale values ​​of multiple pixels is maximized; the feature time is the first moment when the mean or sum of the grayscale values ​​of multiple pixels is maximized.

[0080] The processing system 105 is configured to determine the height information of the sub-region corresponding to each pixel based on the actual distance between the optical component 102 and the fixed plane at the characteristic time. After obtaining the height information of the sub-region corresponding to each pixel, the height information of the measured region is obtained.

[0081] The actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time corresponding to the sub-region can reflect the height of the sub-region. For example, for sub-region A11 of the measured region A, the actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time is h11; for sub-region A12 of the measured region A, the actual distance between the optical component 102 and the fixed plane of the measured object A at the characteristic time is h12. The difference between h11 and h12 is the height difference between sub-region A11 and sub-region A12.

[0082] In some embodiments, a measurement system can be used to measure multiple measurement areas of the object under test, thereby obtaining the height information of each measurement area relative to the same reference plane. After obtaining the height information of each measurement area relative to the same reference plane, the three-dimensional shape of the object under test can be obtained. For example, the height information of multiple measurement areas can be stitched together to obtain the three-dimensional shape of the object under test.

[0083] In some embodiments, see Figure 1 The measurement system also includes a data acquisition system 108, configured to emit a synchronization trigger signal at each of a plurality of first moments. A first detection device 103 is configured to obtain first detection information based on a first beam in response to the synchronization trigger signal. A second detection device 106 is configured to obtain second detection information based on a second beam in response to the synchronization trigger signal. Thus, the first detection device 103 can obtain first detection information at a plurality of first moments, and the second detection device 106 can obtain second detection information at a plurality of first moments. The data acquisition system 108 can acquire the first detection information at a plurality of first moments from the first detection device 103 and the second detection information at a plurality of first moments from the second detection device 106, and transmit them to the processing system 105.

[0084] The following is combined with Figure 2 and Figure 3 Different implementations of the first detection device 103 are described below. It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually.

[0085] Figure 2 This is a schematic diagram of the structure of a measurement system according to other embodiments of the present disclosure.

[0086] like Figure 2As shown, the first detection device 103 is a spectrometer. For example, the first detection device 103 may include a grating 113 and a light intensity detector 123 (e.g., a photodetector). The grating 113 is configured such that light of different wavelengths in the first beam is incident on different regions of the light intensity detector 123, i.e., the grating 113 has a beam-splitting function. The light intensity detector 123 is configured to detect the light intensity of multiple wavelengths of light in the first beam. The processing system 105 can perform subsequent analysis based on the intensity of a predetermined wavelength of light among the multiple wavelengths of light (i.e., the first detection information).

[0087] Figure 3 This is a schematic diagram of the structure of a measurement system according to other embodiments of the present disclosure.

[0088] like Figure 3 As shown, the first detection device 103 may include a filter 113' and a light intensity detector 123. The filter 113' is configured to allow light of a predetermined wavelength from a plurality of wavelengths in the first beam to reach the light intensity detector 123, while light of other wavelengths will not reach the light intensity detector 123. In other words, the filter 113' only allows light of the predetermined wavelength to pass through. In this case, the light intensity detector 123 can directly detect the intensity of the light of the predetermined wavelength.

[0089] In some embodiments, see Figure 2 and Figure 3 The measurement system may also include a first aperture stop 109, such as an aperture stop. The first aperture stop 109 is configured to block a portion of the beam to be processed from entering the first detection device 103 at an angle greater than a first preset angle. In other words, only the portion of the beam to be processed at an angle less than or equal to the first preset angle can enter the first detection device 103. It should be understood that the first preset angle can be determined based on actual conditions. In this case, the first detection device 103 does not need to detect the entire beam to be processed, reducing the adverse effects of light at the edges of the beam and improving detection accuracy.

[0090] The following is combined with Figure 4 and Figure 5 This paper introduces some specific implementation methods for the processing system to determine the actual distance between the optical components and the fixed plane of the object being measured at each first moment.

[0091] Figure 4 This is a flowchart illustrating the process of determining the actual distance between the optical component and the fixed plane of the object under test at each first moment, based on some implementation methods of this disclosure.

[0092] In step 402, the mobile device is controlled to move the optical component relative to the object under test along the optical axis, so as to create a plurality of predetermined distances between the optical component and the fixed plane at a plurality of second moments.

[0093] Here, multiple second moments can be the same as or different from multiple first moments, or they can be partially the same.

[0094] Controlling a mobile device to move an optical component relative to the object under test along the optical axis includes one or a combination of the mobile device moving the optical component or the mobile device moving the object under test.

[0095] In step 404, the first detection information at each of the multiple second time moments is obtained.

[0096] In step 406, based on multiple predetermined distances and multiple first detection information at each second moment, the actual distance between the optical component and the fixed plane of the object under test at each first moment is determined.

[0097] When the mobile device moves only the optical component, determining the actual distance between the optical component and the fixed plane of the object under test at each first moment includes determining the distance between the optical component and any fixed plane at each first moment; when the mobile device moves only the object under test, determining the actual distance between the optical component and the fixed plane of the object under test at each first moment includes determining the distance between the optical component and any fixed plane at each first moment.

[0098] For example, step 406 can be achieved through... Figure 5 This is achieved through steps 416-436 shown.

[0099] In step 416, each of the multiple predetermined distances is linearly processed to obtain a motion parameter. For example, each predetermined distance is multiplied by a constant to obtain the motion parameter.

[0100] In step 426, the function to be fitted is fitted with the difference between the moving parameter and the parameter to be determined at each second time point as the independent variable and the first detection information at each second time point as the dependent variable, so as to obtain the fitted function.

[0101] For example, the function to be fitted may include trigonometric function expansions, polynomials, Fourier expansions, etc.

[0102] In step 436, based on the fitting function and the first detection information at multiple first moments, the actual distance between the optical component and the fixed plane at each first moment is determined.

[0103] The following section uses an optical component 102, including a first beam splitter 112 and a reference mirror 122, and a trigonometric function as an example, to illustrate some specific implementation methods of steps 416-436. The functions of the first beam splitter 112 and the reference mirror 122 can be referred to the description above, and will not be repeated here.

[0104] In this implementation, the first detection information includes the intensity of light at a predetermined wavelength in the beam to be processed. The function to be fitted is: I = A + cos r(x - x0) + B. Here, A is the amplitude of the light intensity at the predetermined wavelength, x0 is the parameter to be determined, B is the average intensity of the light intensity at the predetermined wavelength, r is 1 or 2π / λ, and λ is the wavelength of the light at the predetermined wavelength. In step 416, when the linear processing is multiplied by 2π / λ, r = 1, and the shift parameter is the phase shift; when the linear processing in step 416 is multiplied by 1, r = 2π / λ, and the shift parameter is equal to the predetermined distance.

[0105] For example, the movement parameter at each second time moment is used as x in the function to be fitted, and the intensity of light at a predetermined wavelength at each second time moment is used as I in the function to be fitted. The function to be fitted is fitted to obtain A, the parameter to be determined x0 and B, and thus the fitted function is obtained.

[0106] For example, the intensities of light at predetermined wavelengths at multiple second time points are I1, I2, I3…, and the movement parameter at multiple second time points is x. 01 x 02 x 03 …。 With x 01 x 02 x 03 …taking x as x, and I1, I2, I3… as I as I, the above equation is fitted, for example by least squares fitting, so that A, x0 and B can be obtained, that is, the fitted function is obtained.

[0107] After obtaining A, x0, and B, the relationship between the light intensity I of the predetermined wavelength and the motion parameter x is obtained. Then, using the light intensity of the predetermined wavelength at each first moment as I in the fitting function, x in the fitting function is calculated as the motion parameter at each first moment.

[0108] For example, by substituting the intensities I1', I2', I3'... of light at multiple predetermined wavelengths at the first moment into the fitting function, multiple moving parameters x can be obtained. 11 x12, x 13 …

[0109] Then, based on the movement parameters at each first moment, the actual distance between the optical component and the fixed plane at each first moment is determined.

[0110] For example, the actual distance between the optical component and the fixed plane at each first moment is equal to the motion parameter at each first moment. As another example, the actual distance between the optical component and the fixed plane at each first moment is equal to the ratio of the motion parameter at each first moment to 2Π / λ.

[0111] The relationship between the light intensity of the predetermined wavelength and the moving parameter conforms to the above formula. Therefore, using the above formula as the function to be fitted can simplify the calculation process and improve the detection speed.

[0112] It should be noted that when the processing system 105 measures each measured area, it can fit the corresponding A, x0, and B in the manner described above, and then perform subsequent processing. This method yields a more accurate actual distance between the optical component and the fixed plane at the first moment, thus providing more accurate height information for the measured area.

[0113] It should also be noted that when the function to be fitted is a trigonometric function expansion, polynomial, or Fourier expansion, trigonometric function fitting, polynomial fitting, or Fourier series fitting can be performed on the function to be fitted.

[0114] Figure 6 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure. Figure 7 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure.

[0115] The following is combined with Figures 1-3 ,as well as Figures 6-7 This paper introduces a measurement system according to some embodiments of the present disclosure. It should be noted that the functions of the same or similar components in different embodiments will not be repeated in the following description.

[0116] In some embodiments, the optical component 102 may include a first lens 132. The first lens 132 may be configured to collect a returned beam or a beam to be processed. The following description, in conjunction with different embodiments, will illustrate this further.

[0117] In some embodiments, see Figure 6 The optical assembly 102 also includes a first lens 132 configured to collect the returning beam. In this case, the first beam is formed by at least a portion of the returning beam collected by the first lens 132.

[0118] In some embodiments, see Figure 6 When the first lens 132 is configured to collect the returned beam, the second beam splitter 107 is configured to split the returned beam collected by the first lens 132 to form a second beam and a third beam. The optical assembly 102 is configured to obtain the beam to be processed based on the third beam. The second detection device 106 obtains second detection information based on the second beam. For example, the third beam transmitted through the first beam splitter 112 interferes with the reflected beam reflected by the first beam splitter 112 to obtain the beam to be processed.

[0119] In some embodiments, see Figure 6When the first lens 132 is configured to collect the returning beam, the optical assembly 102 is configured to move relative to the second beam splitter 107. For example, when the mobile device 104 moves the optical assembly 102, the second beam splitter 107 remains relatively stationary.

[0120] In other embodiments, see Figures 1-3 ,as well as Figure 7 The optical assembly 102 also includes a first lens 132 configured to collect the light beam to be processed. In this case, the first light beam is formed by at least a portion of the light beam to be processed collected by the first lens 132.

[0121] In some embodiments, see Figures 1-3 When the first lens 132 is configured to collect the light beam to be processed, the second beam splitter 107 is configured to split the light beam collected by the first lens 132 to form a first beam and a second beam. The first detection device 102 obtains first detection information based on the first beam, and the second detection device 106 obtains second detection information based on the second beam. The optical component 102 is configured to move relative to the second beam splitter 107; for example, when the mobile device 104 moves the optical component 102, the second beam splitter 107 remains relatively stationary. In some embodiments, the light beam to be processed from the first lens 132 can be transmitted through the beam splitter 202 and converged by the converging lens 203 before entering the second beam splitter 107. Alternatively, the light beam to be processed from the first lens 132 can be reflected through the beam splitter 202 and converged by the converging lens 203 before entering the second beam splitter 107.

[0122] In some embodiments, see Figure 7 The optical components may also include a second lens 110 configured to collect the second beam. In this case, the second beam splitter 107 is configured to split the returning beam to obtain the second beam. For example, the second beam may be reflected by the mirror 304 and collected by the second lens 110.

[0123] In some embodiments, see Figure 7 The second lens 110 makes the central axis of the second beam parallel to the direction of movement of the optical component 102, and the second beam splitter 107 is fixedly connected to the optical component 102. In this case, when the optical component 102 moves, the second lens 110 and the second beam splitter 107 can move simultaneously.

[0124] In some embodiments, see Figure 6 or Figure 7 Optical components include lenses (e.g.) Figure 6 Lens 132 or Figure 7The lens 110 is configured to collect the returned light and propagate it to the second beam splitter 107, or the lens is configured to collect the second beam. The second beam splitter 107 is configured to split the returned beam to obtain the second beam. The measurement system may also include a second aperture stop 109, configured to block a portion of the second beam whose angle with the central axis of the second beam is greater than a second preset angle from entering the second detection device 106. In other words, only a portion of the second beam whose angle with the central axis of the second beam is less than or equal to the second preset angle can enter the second detection device 106. It should be understood that the second preset angle can be determined according to actual conditions. Here, both the second aperture stop 109 and the second detection device 106 are conjugate to the focal plane of the lens 132 or the lens 110.

[0125] Specifically, when the lens is configured to collect the returned light and propagate it to the second beam splitter, that is... Figure 6 In the embodiment shown, the lens is a first lens 132; when the lens is configured to collect a second light beam, i.e. Figure 7 In the embodiment shown, the lens is the second lens 110.

[0126] For example, see Figure 6 The second beam is focused by the converging lens 301 and then incident on the second aperture 109. The second beam passing through the second aperture 109 is incident on the converging lens 302, and then focused by the converging lens 303 and incident on the second detection device 106.

[0127] For example, see Figure 7 The second beam collected by the second lens 110 is reflected by the mirror 305 and then incident on the converging lens 306. The second beam is focused by the converging lens 306 and then incident on the second aperture 109. The second beam passing through the second aperture 109 is incident on the converging lens 307, and then focused by the converging lens 307 and then incident on the second detection device 106.

[0128] The second detection device 106 is an imaging device or a light intensity detection component. The imaging device includes a camera or video camera, and the light intensity detection component includes a single photodiode or photomultiplier light.

[0129] exist Figure 6 , Figure 7 In the embodiment shown, when the second detection device 106 is an imaging device or a light intensity detection component, the second detection information includes the light intensity of the second beam.

[0130] When the second detection device 106 is an imaging device, the second detection information includes: a detection image of the area being measured. The second detection information includes one or a combination of the light intensity of the second beam, the contrast of the detection image, and the diffusion of the detection image.

[0131] When the second detection information is the diffusion of the detection image, the diffusion at the characteristic time is less than the diffusion at any first time other than the characteristic time.

[0132] Figures 1-3 , Figure 6 and Figure 7 In the illustrated embodiment, the first detection device 103 and the second detection device 106 detect the same area. The actual distance determined based on the first detection information obtained by the first detection device 103 can represent the height of the area being measured, thereby improving the detection accuracy.

[0133] Figure 8 This is a schematic diagram of the structure of a measurement system according to some embodiments of the present disclosure.

[0134] like Figure 8 As shown, light source 101 includes a first sub-light source 111 and a second sub-light source 121. The first sub-light source 111 is configured to generate a first primary light beam. The second sub-light source 121 is configured to generate a second primary light beam. In other words, the primary light beam generated by light source 101 includes both the first and second primary light beams.

[0135] The returned beams from the measured area of ​​the object A include a first returned beam and a second returned beam. The first returned beam is the first original beam returning from the measured area of ​​the object A. The second returned beam is the second original beam returning from the measured area of ​​the object A.

[0136] The optical assembly 102 includes a first optical assembly 1021 and a second optical assembly 1022 fixedly connected together. The first optical assembly 1021 is configured to form a beam to be processed based on a first returned beam. In this case, the first beam is the beam to be processed. The second optical assembly 1022 is configured to collect a second returned beam. In this case, the second beam is the second returned beam.

[0137] The first detection device 103 is configured to obtain first detection information based on the first beam. The second detection device 106 is configured to obtain second detection information based on the second beam.

[0138] In some embodiments, the first optical component 1021 is further configured to collect a first original light beam and direct the first original light beam to the test area of ​​the object A. The first optical component 1021 includes a dispersive prism configured to converge light of different wavelengths in the first original light beam to different positions on the optical axis of the first optical component 1021.

[0139] The optical axis of the first optical component 1021 is the central axis of the first returning beam.

[0140] In some embodiments, the second optical component 1022 is further configured to collect a second original beam and direct the second original beam to the region to be measured. The second optical component 1022 includes a dispersive prism configured to converge light of different wavelengths in the second original beam to different positions on the optical axis of the second optical component 1022. In other embodiments, the second optical component 1022 may include an interference objective lens configured to obtain an interference beam based on a second returned beam, using the interference beam as the second beam.

[0141] Figure 8 In the embodiment shown, the first detection device 103 is a spectrometer.

[0142] The processing system 105 is configured to determine the actual distance between the optical component 102 and the fixed plane of the object A under test at each of the multiple first moments based on the first detection information at each of the multiple first moments, including: for a certain first moment, obtaining the light intensity of each wavelength in the first beam at that first moment through the first detection device 103; and obtaining the actual distance at that first moment based on the wavelength corresponding to the light intensity with the largest light intensity.

[0143] In some embodiments, the first optical component 1021 is an interference lens, and the first detection device is a spectrometer; the first optical component 1021 is a single lens or a lens group, and the first detection device is a camera or video camera. In another embodiment, the first optical component 1021 is a shaping lens, configured to collect first raw light and emit shaped first raw light towards the object to be tested, wherein the shaped first raw light has a cross-section with different shapes or sizes at different positions along the optical axis of the shaping lens. Specifically, the cross-section of the shaped first raw light is a semicircle and a point, with the arcs of the semicircle pointing in different directions on either side of the point.

[0144] Figure 9 This is a schematic flowchart of a measurement method according to some embodiments of the present disclosure. This measurement method can be implemented based on the measurement system of any of the above embodiments.

[0145] In step 902, the light source generates a raw light beam. Here, the raw light beam returning from the measured area of ​​the object being measured is called the return beam. For example, the raw light beam may include one or a combination of white light, ultraviolet light, and infrared light.

[0146] In step 904, the optical component obtains the beam to be processed based on the returned beam. Here, at least a portion of the beam to be processed is the first beam.

[0147] For example, optical components may include interference lenses or confocal lenses.

[0148] In step 906, first detection information is obtained based on the first beam.

[0149] For example, the first detection device obtains first detection information based on the first light beam. For example, the first detection information includes the light intensity of light at a predetermined wavelength in the light beam to be processed.

[0150] In step 908, the optical component and the object under test are moved relative to each other along the optical axis of the optical component.

[0151] For example, by controlling a mobile device to move at least one of the optical components and the object being measured.

[0152] In step 910, the actual distance between the optical component and the fixed plane at each first moment is determined based on the first detection information at each of the multiple first moments.

[0153] The implementation method of step 910 can be referred to the above description, and will not be repeated here.

[0154] In the above embodiments, the actual distance between the optical component and the fixed plane of the object under test at each first moment can be obtained using the first detection information at multiple first moments. Based on the actual distance between the optical component and the fixed plane of the object under test at each first moment, subsequent operations can be performed more accurately, for example, the height information of the measured area of ​​the object under test can be determined more accurately.

[0155] In some embodiments, Figure 9 The measurement method shown also includes Figure 10 Steps 912-918 are shown. Figure 10 This is a schematic flowchart of a measurement method according to other embodiments of the present disclosure.

[0156] In step 912, second detection information is obtained based on the second beam, which is either a partially returned beam or a partially unprocessed beam. The second detection information characterizes the relative position between the optical component and the measured area.

[0157] For example, obtaining second detection information based on the second beam includes: obtaining a detection image based on the second beam; and obtaining second detection information based on the detection image, wherein the second detection information includes at least one of the light intensity of the second beam and the contrast of the detection image.

[0158] In some embodiments, the second detection information includes the light intensity of the second beam; the light intensity of the second beam at the characteristic moment is greater than the light intensity of the second beam at any of the plurality of first moments other than the characteristic moment.

[0159] In step 914, the first moment when the second detection information is the preset detection information is obtained is taken as the feature moment.

[0160] In step 916, the actual distance between the optical component and the fixed plane at the characteristic moment is obtained.

[0161] In step 918, the height information of the measured area is determined based on the actual distance between the optical component and the fixed plane at the characteristic time.

[0162] In some embodiments, the measurement method further includes: obtaining the shape of the object under test based on the height information of multiple measured areas relative to the same reference plane.

[0163] In some embodiments, obtaining the morphology of the object under test based on the height information of multiple measured regions relative to the same reference plane includes: repeatedly generating an original light beam from the light source for each measured region; determining the height information of the measured region based on the actual distance between the optical component and the fixed surface at a characteristic moment; obtaining the height information of each measured region relative to the same reference plane; and obtaining the morphology of the object under test based on the height information of each measured region relative to the same reference plane.

[0164] For example, the step of obtaining the height information of each measured area relative to the same reference plane includes: repeating steps 902 to 918 to obtain the height of each measured area relative to the initial reference plane; and unifying the initial reference plane of each measured area to the same reference plane.

[0165] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0166] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0167] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A measurement system characterized by, The measurement system comprises: a light source configured to generate an original light beam, wherein the original light beam returned from a measured region of a measured object forms a return light beam; an optical assembly configured to obtain a to-be-processed light beam from the return light beam, wherein at least part of the to-be-processed light beam is a first light beam; a first detection device configured to obtain first detection information from the first light beam, the first detection device comprising at least a light intensity detector; a moving device configured to move the optical assembly and the measured object relative to each other along an optical axis direction of the optical assembly; and a processing system configured to determine an actual distance between the optical assembly and a fixed plane of the measured object at each of a plurality of first time points according to the first detection information at each of the first time points. a second detection device configured to obtain second detection information from a second light beam, the second light beam being part of the return light beam or part of the to-be-processed light beam, the second detection information representing a relative distance between the optical assembly and the measured region along the optical axis direction of the optical assembly, the second detection information comprising a light intensity of the second light beam, the second detection device comprising a light intensity detection component; the processing system is further configured to obtain a first time point at which the second detection information is preset detection information as a feature time point, and obtain an actual distance between the optical assembly and the fixed plane at the feature time point, wherein the light intensity of the second light beam at the feature time point is maximum. determine height information of the measured region according to the actual distance between the optical assembly and the fixed plane at the feature time point.

2. The measurement system of claim 1, wherein, The optical assembly comprises: a first beam splitter configured to split the original light beam into a reference light beam and an object light beam incident on the measured region, wherein the object light beam returned from the measured region to the optical assembly forms the return light beam; and a reference mirror configured to propagate the reference light beam along a preset track to obtain a pre-interference light beam, wherein the pre-interference light beam and the return light beam interfere to obtain the to-be-processed light beam. The first detection information comprises an intensity of light of a predetermined wavelength in the to-be-processed light beam.

3. The measurement system according to claim 2, wherein the reference mirror is configured to propagate the reference light beam along a preset track to obtain a pre-interference light beam by reflecting the reference light beam; the reference mirror and the first beam splitter are both half-transmissive half-reflective mirrors, and the reference mirror and the first beam splitter are arranged in parallel; or the reference mirror is a reflective mirror.

4. The measurement system of claim 1, wherein, The measurement system further comprises: a second beam splitter configured to split the return light beam or the to-be-processed light beam to obtain the second light beam.

5. The measurement system of claim 4, wherein, The optical assembly further comprises: a first lens configured to collect the return light beam, the first light beam being formed by at least part of the return light beam collected by the first lens; or the first lens is configured to collect the to-be-processed light beam, the first light beam being formed by at least part of the to-be-processed light beam collected by the first lens.

6. The measurement system according to claim 5, wherein When the first lens is configured to collect the return light beam, the second beam splitter is configured to split the return light beam collected by the first lens to form the second light beam and a third light beam, and the optical assembly is configured to obtain the to-be-processed light beam according to the third light beam; When the first lens is configured to collect the to-be-processed light beam, the second beam splitter is configured to split the to-be-processed light beam collected by the first lens to form the first light beam and the second light beam.

7. The measurement system of claim 5, wherein, The optical assembly further comprises a second lens configured to collect the second light beam.

8. The measurement system according to claim 7, wherein The second beam splitter is configured to split the return light beam to obtain the second light beam, and the second lens is configured to make the central axis of the second light beam parallel to the moving direction of the optical assembly. The second beam splitter is fixedly connected with the optical assembly.

9. The measurement system according to claim 6, wherein The optical assembly is configured to move relative to the second beam splitter.

10. The measurement system according to claim 4, wherein The second beam splitter is configured to split the return light beam to obtain the second light beam; The optical assembly comprises a lens configured to collect the return light beam and propagate the return light beam to the second beam splitter, or the lens is configured to collect the second light beam; The measurement system further comprises: A second light barrier configured to block the part of the second light beam with an included angle greater than a second preset included angle between the central axis of the second light beam from entering the second detection device, and the second light barrier and the second detection device are conjugated with the focal plane of the lens.

11. The measurement system according to claim 1, wherein The original light beam comprises a first original light beam and a second original light beam; The light source comprises: A first sub-light source configured to generate the first original light beam, and A second sub-light source configured to generate the second original light beam; The return light beam comprises a first return light beam and a second return light beam, the first return light beam being the first original light beam returned from the measured region, and the second return light beam being the second original light beam returned from the measured region; The optical assembly comprises: A first optical assembly configured to form the to-be-processed light beam according to the first return light beam, the first light beam being the to-be-processed light beam, and A second optical assembly configured to collect the second return light beam, the second light beam being the second return light beam, and the first optical assembly and the second optical assembly being fixedly connected.

12. A measurement method of the measurement system according to any one of claims 1 to 11, characterized by, comprising: A light source generating an original light beam, wherein the original light beam returned from a measured region of a measured object is a return light beam; An optical assembly obtaining a to-be-processed light beam according to the return light beam, at least part of the to-be-processed light beam being a first light beam, and obtaining first detection information according to the first light beam; Moving the optical assembly and the measured object relative to each other along the optical axis direction of the optical assembly; and According to the first detection information at each of the plurality of first time points, an actual distance between the optical assembly and the fixed plane at each of the first time points is determined; Second detection information is obtained according to a second light beam, the second light beam being part of the return light beam or part of the to-be-processed light beam, the second detection information representing a relative distance between the optical assembly and the measured region in a direction of an optical axis of the optical assembly, the second detection information including a light intensity of the second light beam; A first time point at which the second detection information is preset detection information is obtained as a feature time point, and the actual distance between the optical assembly and the fixed plane at the feature time point is obtained, wherein the light intensity of the second light beam at the feature time point is maximum; According to the actual distance between the optical assembly and the fixed plane at the feature time point, height information of the measured region is determined.

13. The method of measuring according to claim 12, wherein, Further comprising: The number of the measured regions is multiple; The processing system is configured to repeat, for each measured region, the steps of generating, by a light source, an original light beam, and determining, according to the actual distance between the optical assembly and the fixed plane at the feature time point, the height information of the measured region, to obtain height information of each measured region relative to a same reference plane; According to the height information of each measured region relative to the same reference plane, a topography of the object to be measured is obtained.

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