Focus Search Method, Semiconductor Detection Method, Detection Device, and Storage Medium

Abstract

The present application discloses a focus finding method, a detection method for semiconductors, a detection device, and a storage medium, belonging to the technical field of semiconductor detection. The method includes: controlling the relative movement in the vertical direction between a stage carrying a reference object and a to-be-detected object and an objective lens, so that the reference object carried on the stage and the objective lens are successively at a plurality of different height distances in the vertical direction; wherein, the stage has a first carrying area and a second carrying area. At each height distance, controlling the taking of a picture of the reference object on the stage to obtain a reference image of the reference object at each height distance. Based on the reference images of the reference object at a plurality of different height distances, a target height distance is determined, and the target height distance is used to determine the initial height distance between the stage or the to-be-detected object and the objective lens when scanning the to-be-detected object. By introducing a reference object, the present application can improve the accuracy of the determined target height distance.

Description

Technical Field

[0001] The present application relates to the field of semiconductor detection technology, and specifically relates to a focusing method, a semiconductor detection method, a detection device, and a storage medium. Background Art

[0002] When detecting a semiconductor, the optimal object plane position is easily affected by environmental factors, resulting in focal plane drift. If not corrected, it may reduce the imaging quality and affect the accuracy and stability of defect detection. Therefore, to ensure that the image quality obtained during the wafer testing process remains in the best state, it is necessary to accurately evaluate the optimal object distance of the current objective lens imaging before each wafer test. However, for a dark field detection system, it is often affected by the object-side structure during the focusing process. That is to say, when the dark field detection system images an object with a periodic structure, a series of clear periodic images will be formed during the focusing process, thus interfering with the judgment of the optimal object distance. In addition, the surface pattern of a patterned wafer usually has unpredictable structural fluctuations. If focusing is performed with the unknown pattern of the patterned wafer as the object plane, it will also cause the focusing to deviate from the optimal imaging object distance. Summary of the Invention

[0003] Aiming at the problems existing in the prior art, the present application provides a focusing method, a semiconductor detection method, a detection device, and a storage medium. By introducing a reference object, the accuracy of the determined target height distance can be improved, so as to perform accurate focusing. The technical solutions are as follows:

[0004] On the one hand, a focusing method is provided, and the method includes:

[0005] Controlling the relative movement in the vertical direction between the stage carrying the reference object and the object to be measured and the objective lens, so that the reference object carried on the stage and the objective lens are successively at multiple different height distances in the vertical direction; wherein, the stage has a first carrying area and a second carrying area, the first carrying area is used for carrying the object to be measured, and the second carrying area is used for carrying the reference object;

[0006] At each height distance, controlling to photograph the reference object on the stage to obtain a reference image of the reference object at each height distance;

[0007] Based on the reference images of the reference object at multiple different height distances, determining a target height distance, where the target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

[0008] Optionally, after determining the target height distance based on the reference images of the reference object at multiple different height distances, the method further includes:

[0009] Control the stage to move to a corresponding height in the vertical direction according to the target height distance, and obtain the height value of the upper surface of the reference object when the stage is at this height as the target height value, where the target height value is used to indicate the height value that the upper surface of the measurement area corresponding to the object to be measured at the initial scanning position needs to be at.

[0010] Optionally, determining the target height distance based on the reference images at multiple different height distances includes:

[0011] For each of the multiple reference images: determine multiple regions of interest in the reference image; determine the region energy concentration values corresponding to the multiple regions of interest respectively; based on the multiple region energy concentration values, determine the image energy concentration value corresponding to the reference image;

[0012] Based on the image energy concentration values corresponding to the multiple reference images respectively and the height distances corresponding to the multiple reference images respectively, determine the target height distance.

[0013] Optionally, determining the image energy concentration value corresponding to the reference image based on the multiple region energy concentration values includes:

[0014] Take the average value of the multiple region energy concentration values as the image energy concentration value corresponding to the reference image.

[0015] Optionally, determining the target height distance based on the image energy concentration values corresponding to the multiple reference images respectively and the height distances corresponding to the multiple reference images respectively includes:

[0016] Obtain a reference curve graph according to the multiple image energy concentration values and the height distances corresponding to the multiple reference images respectively;

[0017] Determine the height distance corresponding to the largest image energy concentration value in the reference curve graph as the target height distance.

[0018] Optionally, determining the region energy concentration values corresponding to the multiple regions of interest respectively includes:

[0019] For each of the multiple regions of interest:

[0020] Determine the central pixel in the region of interest, where the central pixel is the pixel with the largest gray value in the region of interest;

[0021] Taking the central pixel as the center, determine a first sub-region, a second sub-region, and a third sub-region in the region of interest, where the first sub-region is located on the periphery of the central pixel, the second sub-region is located on the periphery of the first sub-region, and the third sub-region is the other region in the region of interest that is located on the periphery of the second sub-region;

[0022] Based on the first sub-region, the second sub-region, and the third sub-region, determine corresponding region energy concentration values.

[0023] Optionally, the determining corresponding region energy concentration values based on the first sub-region, the second sub-region, and the third sub-region includes:

[0024] Based on the pixels in the second sub-region and the pixels in the third sub-region, determine the average noise;

[0025] Determine a plurality of gray pixels in the first sub-region, where the plurality of gray pixels includes a first pixel with the largest gray value in the first sub-region and at least one pixel whose gray value is sequentially less than the gray value of the first pixel;

[0026] Based on the plurality of gray pixels and the average noise, determine a first energy value;

[0027] Based on the pixels in the second sub-region and the average noise, determine a second energy value;

[0028] Based on the first energy value and the second energy value, determine the region energy concentration value.

[0029] Optionally, the determining a first energy value based on the plurality of gray pixels and the average noise includes:

[0030] Subtract the average noise from each of the plurality of gray pixels to obtain a plurality of gray pixels after subtracting the average noise;

[0031] Add up the gray values of the plurality of gray pixels after subtracting the average noise to obtain the first energy value.

[0032] Optionally, the determining a second energy value based on the pixels in the second sub-region and the average noise includes:

[0033] Subtract the average noise from each pixel in the second sub-region to obtain a plurality of pixels after subtracting the average noise;

[0034] Add up the gray values of the plurality of pixels after subtracting the average noise to obtain the second energy value.

[0035] Optionally, determining the regional energy concentration value based on the first energy value and the second energy value includes:

[0036] Determining the ratio of the first energy value to the second energy value as the regional energy concentration value.

[0037] Optionally, the reference object is a standard part, and the surface of the standard part has a plurality of circular pits with the same diameter and the same depression distance, and the plurality of circular pits are arranged in a rectangle; or,

[0038] The reference object is another object to be measured of a different type from the object to be measured located in the first bearing area.

[0039] Optionally, the bottom surfaces of the first bearing area and the second bearing area are on the same horizontal plane.

[0040] On the other hand, a focusing method is provided, and the method includes:

[0041] Controlling the relative movement in the vertical direction between the stage carrying the reference object and the objective lens, so that the reference object carried on the stage and the objective lens are successively at a plurality of different height distances in the vertical direction;

[0042] At each height distance, controlling to photograph the reference object on the stage to obtain a reference image of the reference object at each height distance;

[0043] Based on the reference images of the reference object at a plurality of different height distances, determining a target height distance, where the target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured on the stage.

[0044] Optionally, the stage has a first bearing area for bearing the object to be measured; the reference object is the object to be measured.

[0045] Optionally, determining the target height distance based on the reference images of the reference object at a plurality of different height distances includes:

[0046] For each of the plurality of reference images: determining a plurality of regions of interest in the reference image; determining the regional energy concentration values respectively corresponding to the plurality of regions of interest; based on the plurality of regional energy concentration values, determining the image energy concentration value corresponding to the reference image;

[0047] Based on the image energy concentration values respectively corresponding to the plurality of reference images and the height distances respectively corresponding to the plurality of reference images, determining the target height distance.

[0048] On the other hand, a method for detecting a semiconductor is provided, the method comprising:

[0049] Controlling the relative movement of a stage carrying an object to be measured and an objective lens along a scanning direction to sequentially reach a plurality of scanning positions, where the object to be measured is a semiconductor sample; wherein, controlling the relative movement of the stage and the objective lens in a vertical direction according to a target height distance such that the upper surface of a region to be measured corresponding to the object to be measured at an initial scanning position is at a desired height, and the target height distance is determined based on the above-mentioned focusing method;

[0050] During the scanning process, using the upper surface of the region to be measured corresponding to the object to be measured at the initial scanning position being at the desired height as a focus-following zero point to control full following focusing on the object to be measured, and after automatic focusing at each scanning position, controlling imaging of the object to be measured to obtain a measurement image of the region to be measured corresponding to the object to be measured at the current scanning position;

[0051] Detecting the region to be measured based on the measurement image.

[0052] On the other hand, a detection device is provided, comprising:

[0053] A stage having a first carrying region for carrying an object to be measured;

[0054] An imaging optical path assembly including a detection sensor and an objective lens; the imaging optical path assembly is configured to optically image the object to be measured and a reference object on the stage through the objective lens, and transmit the imaged optical signal to the detection sensor, and the detection sensor is configured to convert the optical signal into an electrical signal, so as to obtain a detection image of the object to be measured and / or a reference image of the reference object;

[0055] A driving assembly for driving the relative movement of the stage and the objective lens;

[0056] A processor for executing the method described in any one of the embodiments herein.

[0057] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned focusing method or the semiconductor detection method are implemented.

[0058] On the other hand, a computer program product including instructions is provided, and when the instructions run on a computer, the computer is caused to execute the steps of the above-mentioned focusing method or the semiconductor detection method.

[0059] The technical solution provided by the present application can at least bring the following beneficial effects:

[0060] By introducing a reference object, and the reference object is located in the second bearing area of the stage, by controlling the relative movement of the stage and the objective lens in the vertical direction, and at each height distance, controlling the shooting of the reference object on the stage, a plurality of reference images can be obtained. Then, according to the reference images of the reference object at multiple different height distances, the target height distance is determined. That is, the embodiment of the present application performs focus searching based on the reference object. Thus, it can avoid the situation that it is difficult to find a fixed graphic feature as the object for focus imaging due to different graphic types corresponding to different regions of the object to be measured, improve the accuracy of focus searching, thereby improving the imaging quality of the object to be measured in the subsequent process, and further improving the detection accuracy of the object to be measured; moreover, it can avoid the situation of errors caused by the undulation of the graphic structure of the object to be measured and the Talbot effect when directly focusing on the object to be measured.

[0061] In addition, according to the multiple image energy concentration values and the height distances corresponding to the multiple reference images, a reference curve graph is determined. Thus, in the subsequent process, the target height distance can be directly determined from the reference curve graph. Moreover, taking the average value of the multiple region energy concentration values as the image energy concentration value corresponding to the reference image can improve the accuracy of the determined target height distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is a schematic structural diagram of a detection device provided by an embodiment of the present application;

[0063] Figure 2 is a flowchart of a focus searching method provided by an embodiment of the present application;

[0064] Figure 3 is a schematic structural diagram of a stage provided by an embodiment of the present application;

[0065] Figure 4 is a schematic structural diagram of a standard part provided by an embodiment of the present application;

[0066] Figure 5 is a schematic diagram of a reference image provided by an embodiment of the present application;

[0067] Figure 6 is a schematic diagram of a region of interest provided by an embodiment of the present application;

[0068] Figure 7 is a schematic diagram of a reference curve graph provided by an embodiment of the present application;

[0069] Figure 8 is a flowchart of another focus searching method provided by an embodiment of the present application;

[0070] Figure 9Flowchart of a semiconductor detection method provided by an embodiment of this application. Detailed implementation manners

[0071] The present invention will be further described in detail below in conjunction with the accompanying drawings through specific implementation manners. Similar elements in different implementation manners are labeled with related similar element numbers. In the following implementation manners, many details are described to enable a better understanding of this application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to this application are not shown or described in the specification, in order to avoid the core part of this application being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0072] In addition, the features, operations, or characteristics described in the specification can be combined in any appropriate manner to form various implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner for those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment, and do not mean that they are the necessary sequences, unless it is stated otherwise that a certain sequence must be followed.

[0073] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. And the "connection" and "coupling" mentioned in this application, unless otherwise specified, both include direct and indirect connection (coupling).

[0074] Before explaining the focusing method, semiconductor detection method, detection device, and storage medium provided by this application in detail, the application scenarios and implementation environments of the embodiments of this application will be introduced first.

[0075] In a detection system, environmental factors (such as temperature changes, mechanical vibrations, etc.) can affect the position of the optimal object surface. If no correction is made, it may reduce the imaging quality, thereby affecting the accuracy and stability of detection. In related technologies, autofocus solutions mainly rely on image contrast analysis to determine the optimal object distance. However, in a dark-field imaging system, due to the significant influence of the object-side structure, it is difficult to accurately determine the focal plane position. Especially when imaging a sample with a periodic structure under coherent illumination, the Talbot effect may occur, resulting in a series of clear periodic images, making it difficult to accurately judge the optimal object distance. In addition, the surface pattern of the object to be measured usually has unpredictable structural fluctuations. Focusing directly on its pattern may cause the focal plane to shift, affecting the imaging clarity and the accuracy of defect detection.

[0076] Based on this, in the embodiments of the present application, a reference object is introduced, and the height distance of the optimal object distance is obtained by imaging the standard object and used as the initial following focus height to be input into the autofocus system, realizing dynamic adjustment during the full-chip scanning process, ensuring that the imaging system can accurately follow automatically and always maintain the optimal focal plane. It can effectively reduce the interference of environmental changes and sample structures on the focusing process, thereby improving the accuracy and stability of autofocus and enhancing the reliability and consistency of detection results.

[0077] Please refer to Figure 1 , Figure 1 FIG. is a schematic structural diagram of a detection device provided by an embodiment of the present application. The detection device includes a stage 1, an imaging optical path assembly 2, a driving assembly 3, and a processor 4. Among them, the imaging optical path assembly 2 includes a detection sensor 21 and an objective lens 22.

[0078] Among them, the stage 1 has a first carrying area 11, and the first carrying area 11 is used to carry the object to be measured.

[0079] In some embodiments, the stage 1 can move, and after the stage 1 moves, it can drive the carried object to be measured to move.

[0080] In some embodiments, the stage 1 can move along the scanning direction, thereby driving the carried object to be measured to move along the scanning direction, so that the detection device can scan the entire surface of the object to be measured.

[0081] In some embodiments, the scanning direction can be the X-axis direction, the Y-axis direction, or the plane direction defined by the X-axis and the Y-axis (such as the horizontal direction or the horizontal plane direction).

[0082] In some embodiments, the stage 1 can move along the optical axis direction of the objective lens 22, thereby driving the carried object to be measured to move along the optical axis direction of the objective lens 22. Exemplarily, the optical axis direction of the objective lens 22 can be the Z-axis direction (such as the vertical direction).

[0083] Therefore, in some embodiments, the stage 1 can move along the Z-axis direction (e.g., the vertical direction), thereby driving the object to be measured carried thereon to move along the Z-axis direction (e.g., the vertical direction).

[0084] In addition, in some embodiments, in order to perform focusing by means of a reference object, that is, to determine the target height distance by means of the reference object, please refer to Figure 1 , the stage 1 further has a second carrying area 12 for carrying the reference object. Thus, when the stage 1 moves, it can also drive the carried reference object to move to perform related steps.

[0085] It should be noted that the object to be measured in the embodiments of the present application can be semiconductor products such as wafers and chips. Since there may be defects such as flaws on their surfaces, it is necessary to perform optical detection on their surfaces to control the quality of the products.

[0086] The imaging optical path assembly 2 is used to optically image the object to be measured and the reference object on the stage 1 through the objective lens 22, and transmit the imaged optical signal to the detection sensor 21. The detection sensor 21 is used to convert the optical signal into an electrical signal, so as to obtain the detection image of the object to be measured and / or the reference image of the reference object.

[0087] In some embodiments, the detection sensor 21 can be a TDI (Time Delayed and Integration) camera.

[0088] It should be noted that in addition to the detection sensor 21 and the objective lens 22, the imaging optical path assembly 2 may further include other components, such as other optical devices disposed in the optical path between the detection sensor 21 and the objective lens 22, such as a collimating lens, and even a filter, a beam splitter, etc.; in addition, the imaging optical path assembly 2 may further include a light source. The illumination light emitted by the light source is projected onto the object to be measured carried on the stage 1 through the objective lens 22, and the light formed by the reflection and scattering on the surface of the object to be measured is then collected by the objective lens 22 and incident on the detection sensor 21. The light source can be any one of an LED (Light Emitting Diode), a xenon lamp, a mercury lamp, a halogen lamp, a laser lamp, a laser plasma lamp, a laser-driven white light source lamp, so the illumination light can be white light, colored light or laser light.

[0089] The driving assembly 3 is used to drive the relative movement of the stage 1 and the objective lens 22. It can be that the driving assembly 3 drives the stage 1 to move while the objective lens 22 remains stationary, or the driving assembly 3 drives the objective lens 22 to move while the stage 1 remains stationary, or the driving assembly 3 drives the stage 1 to move and drives the objective lens 22 to move.

[0090] Exemplarily, the driving component 3 drives the stage 1 and the objective lens 22 to move relative to each other in the scanning direction. It can be that the driving component 3 drives the stage 1 to move in the scanning direction while the objective lens 22 remains stationary, or the driving component 3 drives the objective lens 22 to move in the scanning direction while the stage 1 remains stationary, or the driving component 3 drives the stage 1 to move and drives the objective lens 22 to move to achieve relative movement of the two along the scanning direction.

[0091] Again exemplarily, the driving component 3 drives the stage 1 and the objective lens 22 to move relative to each other along the optical axis direction of the objective lens 22. It can be that the driving component 3 drives the stage 1 to move along the optical axis direction while the objective lens 22 remains stationary, or the driving component 3 drives the objective lens 22 to move along the optical axis direction while the stage 1 remains stationary, or the driving component 3 drives the stage 1 to move and drives the objective lens 22 to move to achieve relative movement of the two along the optical axis direction.

[0092] Therefore, the driving component 3 drives the stage 1 and the objective lens 22 to move relative to each other along the Z-axis direction (for example, the vertical direction). It can be that the driving component 3 drives the stage 1 to move along the Z-axis direction (for example, the vertical direction) while the objective lens 22 remains stationary, or the driving component 3 drives the objective lens 22 to move along the Z-axis direction (for example, the vertical direction) while the stage 1 remains stationary, or the driving component 3 drives the stage 1 to move and drives the objective lens 22 to move to achieve relative movement of the two along the Z-axis direction (for example, the vertical direction).

[0093] In some embodiments, the driving component 3 can be implemented based on driving components such as piezoelectric, servo motors, and DD motors.

[0094] The processor 4 includes, but is not limited to, a central processing unit (CPU), a microcontroller unit (MCU), a field-programmable gate array (FPGA), and a digital signal processing (DSP), etc., which are devices for interpreting computer instructions and processing data in computer software.

[0095] In some embodiments, the processor 4 is capable of executing each computer application program in the non-transitory computer-readable storage medium, thereby performing corresponding steps and methods. For example, the processor 4 can be implemented by software, hardware, firmware, or a combination thereof, and can use circuits, one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), central processing units (CPUs), controllers, microcontrollers, microprocessors, such that the processor 4 can perform some steps, all steps, or any combination of the steps of the focusing method in various embodiments of the present application, or such that the processor 4 can perform some steps, all steps, or any combination of the steps of the semiconductor detection method in various embodiments of the present application.

[0096] Next, a detailed explanation of the focusing method provided by the embodiments of the present application will be given.

[0097] Figure 2 It is a flowchart of a focusing method provided by an embodiment of the present application, and this method is applied to the processor in the above detection device. Please refer to Figure 2 This method includes the following steps:

[0098] Step 201: Control the relative movement in the vertical direction between the stage carrying the reference object and the object to be measured and the objective lens, so that the reference object carried on the stage and the objective lens are successively at multiple different height distances in the vertical direction; wherein, the stage has a first carrying area and a second carrying area, the first carrying area is used to carry the object to be measured, and the second carrying area is used to carry the reference object.

[0099] When detecting the object to be measured, since the graphic types corresponding to each area of the object to be measured may be different, it is difficult to find a fixed graphic feature as the object for focus imaging. Therefore, a second carrying area for carrying the reference object can be added to the stage in addition to the first carrying area for carrying the object to be measured, for the subsequent focusing process.

[0100] In some embodiments, it is possible to control the movement of the stage carrying the reference object and the object to be measured, keep the objective lens stationary, and move the stage in the horizontal direction so that the reference object carried on the stage is located directly below the objective lens. Subsequently, it is also possible to control the stage to move in the vertical direction so that the reference object carried on the stage and the objective lens are successively at multiple different height distances in the vertical direction.

[0101] In addition, in some embodiments, it is also possible to control the movement of the objective lens, keep the stage stationary, and move the objective lens in the horizontal direction so that the objective lens is located directly above the reference object carried on the stage. Subsequently, it is also possible to control the objective lens to move in the vertical direction so that the reference object carried on the stage and the objective lens are successively at multiple different height distances in the vertical direction.

[0102] In some embodiments, the first carrying area and the second carrying area of the stage are as Figure 3 shown, and it can be seen from Figure 3 that the first carrying area is used to carry the object to be measured, the second carrying area is used to carry the reference object, and the second carrying area is connected to the second carrying area. Thus, without having to move the stage or the objective lens significantly, it is possible to switch the imaging object between the object to be measured and the reference object.

[0103] In some embodiments, the reference object can be a standard part, and the surface of the standard part has a plurality of circular pits with the same diameter and the same depression distance, and the plurality of circular pits are arranged in a rectangular pattern; alternatively, the reference object can also be another object to be measured of a different type from the object to be measured located in the first carrying area.

[0104] As an example, the reference object can be a standard part as Figure 4 shown, and it can be seen from Figure 4 that the depression distance of the plurality of circular pits in the standard part is all d.

[0105] It should be noted that the reference object can be a standard part, or it can also be another object to be measured of a different type from the object to be measured in the first carrying area, and the embodiments of the present application do not make any limitations in this regard.

[0106] In some embodiments, the bottom surfaces of the first carrying area and the second carrying area are in the same horizontal plane, and thus, it is possible to ensure that the object to be measured and the reference object are placed on the same horizontal plane.

[0107] Step 202: At each height distance, control the shooting of the reference object on the stage to obtain a reference image of the reference object at each height distance.

[0108] That is to say, after each relative movement of the stage and the objective lens in the vertical direction, it is necessary to control the photographing of the reference object on the stage at this height distance; after the photographing at this height distance is completed, the height distance between the reference object and the objective lens in the vertical direction can be changed, and then the photographing of the reference object on the stage is controlled. Repeat the above steps to obtain the reference images of the reference object at each height distance, that is, multiple reference images can be obtained, and the height distances corresponding to each reference image in the multiple reference images are different.

[0109] Step 203: Based on the reference images of the reference object at multiple different height distances, determine the target height distance, which is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

[0110] After obtaining the reference images of the reference object at multiple different height distances, the target height distance can be determined based on the multiple reference images.

[0111] In some embodiments, the bottom surfaces of the first and second bearing areas of the stage are on the same horizontal plane, and the upper surface of the object to be measured is also on the same horizontal plane as the upper surface of the reference object. Therefore, the target height distance determined according to the reference image corresponding to the reference object can be used to determine the initial height distance between the stage and the objective lens when scanning the object to be measured.

[0112] In addition, in some embodiments, it may be due to the bottom surfaces of the first and second bearing areas of the stage not being on the same horizontal plane, or due to the thickness of the object to be measured being different from the thickness of the reference object, resulting in the upper surface of the object to be measured not being on the same horizontal plane as the upper surface of the reference object. Therefore, the target height distance determined according to the reference image corresponding to the reference object can be used to determine the initial height distance between the upper surface of the object to be measured and the objective lens when scanning the object to be measured. That is to say, the target height distance determined according to the multiple reference images is the height distance between the upper surface of the reference object and the objective lens. Therefore, the initial height distance between the upper surface of the object to be measured and the objective lens should be equal to the target height distance.

[0113] In some embodiments, for each reference image in the multiple reference images: multiple regions of interest (i.e., ROI, Region of Interest) in the reference image can be determined, and then, the region energy concentration values corresponding to the multiple regions of interest are determined, and based on the multiple region energy concentration values, the image energy concentration value corresponding to the reference image is determined. After that, based on the image energy concentration values corresponding to the multiple reference images and the height distances corresponding to the multiple reference images, the target height distance is determined.

[0114] That is to say, after obtaining the multiple reference images, it is necessary to determine corresponding multiple regions of interest for each reference image, and for each region of interest among the multiple regions of interest, a corresponding regional energy concentration value needs to be determined, so as to obtain multiple regional energy concentration values corresponding to each reference image, and then, based on the multiple regional energy concentration values, determine the image energy concentration value corresponding to each reference image.

[0115] As an example, please refer to Figure 5 , Figure 5 which is a schematic diagram of a reference image provided by an embodiment of the present application. As can be seen from Figure 5 , the reference image includes multiple regions. A total of 9 regions within the dashed box are selected as regions of interest from the multiple regions. After that, it is necessary to determine the regional energy concentration values corresponding to these 9 regions respectively, and 9 regional energy concentration values can be obtained. Thus, the image energy concentration value corresponding to this reference image can be determined based on these 9 regional energy concentration values.

[0116] It should be noted that the above is described by taking 9 regions of interest as an example. Alternatively, in applications, more or fewer arbitrary regions in the reference image can also be selected as regions of interest according to the situation. The embodiments of the present application do not make any limitations in this regard.

[0117] In some embodiments, the regional energy concentration value corresponding to each region of interest among the multiple regions of interest can be determined according to the following steps (1)-(3);

[0118] (1) Determine the central pixel in the region of interest, and this central pixel is the pixel with the largest gray value in the region of interest.

[0119] That is to say, the pixel with the largest gray value in the region of interest can be determined as the central pixel. By way of example, please refer to Figure 6 , Figure 6 which is a schematic diagram of a region of interest provided by an embodiment of the present application, and this central pixel is the gray area A0 in Figure 6 .

[0120] (2) With the central pixel as the center, determine the first sub-region, the second sub-region, and the third sub-region in the region of interest. The first sub-region is located outside the central pixel, the second sub-region is located outside the first sub-region, and the third sub-region is the other region in the region of interest that is located outside the second sub-region.

[0121] As an example, please refer to Figure 6 , the first sub-region is the white area A1 in Figure 6 , the second sub-region is the shaded part A2 in Figure 6 , and the third sub-region is the black area A3 in Figure 6 .

[0122] It should be noted that Figure 6 The area sizes of the first sub-region, the second sub-region, and the third sub-region are only for illustrative purposes. In actual applications, the area sizes of the first sub-region, the second sub-region, and the third sub-region can be changed according to the situation. The embodiments of the present application do not limit this.

[0123] (3) Based on the first sub-region, the second sub-region, and the third sub-region, determine the corresponding regional energy concentration values.

[0124] In some embodiments, the corresponding regional energy concentration values can be determined based on the first sub-region, the second sub-region, and the third sub-region according to the following steps a - e;

[0125] a. Based on the pixels in the second sub-region and the pixels in the third sub-region, determine the average noise.

[0126] Since both the second sub-region and the third sub-region include multiple pixels, it is necessary to calculate the noise value of each pixel among the multiple pixels. Exemplarily, the noise value of each pixel is the difference between the pixel in the noisy image and the pixel in the region of interest, where the noisy image refers to an image in which pixel values undergo unexpected random changes due to various interferences. Such images usually contain abnormal brightness or color fluctuations that do not originate from the original scene.

[0127] It should be noted that the above description is based on determining the noise of each pixel according to the difference between the noisy image and the region of interest. Alternatively, in applications, the noise of each pixel can also be determined by other means.

[0128] It should be noted that after obtaining the noises corresponding to the multiple pixels in the second sub-region and the third sub-region, the average of the multiple noises can be calculated, and the obtained average value can be determined as the average noise. Alternatively, the standard deviation or median of the multiple noises can also be calculated to determine the average noise. The embodiments of the present application do not limit this.

[0129] b. Determine multiple gray pixels in the first sub-region, where the multiple gray pixels include a first pixel with the largest gray value in the first sub-region and at least one pixel with a gray value that is successively smaller than the gray value of the first pixel.

[0130] That is to say, it is necessary to determine multiple pixels with the largest gray values in the first sub-region, that is, the multiple gray pixels include the first pixel with the largest gray value in the first sub-region and at least one pixel with a gray value smaller than that of the first pixel in sequence. As an example, assume that there are pixels P1, P2, P3, P4, P5, and P6 in the first sub-region, and pixel P1 is the pixel with the largest gray value in the first sub-region, and the gray values of pixels P2, P3, P4, P5, and P6 decrease in sequence; if 4 gray pixels need to be selected, then pixels P1, P2, P3, and P4 can be determined as gray pixels.

[0131] c. Determine a first energy value based on the multiple gray pixels and the average noise.

[0132] In some embodiments, the average noise can be subtracted from each of the multiple gray pixels to obtain multiple gray pixels after subtracting the average noise, and then, the gray values of the multiple gray pixels after subtracting the average noise are added together to obtain the first energy value.

[0133] After determining the multiple gray pixels and the average noise, it is necessary to subtract the average noise from each of the multiple gray pixels to reduce the interference of noise, thereby improving the accuracy of the determined regional energy concentration value. Then, for the multiple gray pixels after subtracting the average noise, the gray value of each gray pixel is determined to obtain the gray values corresponding to the multiple gray pixels after subtracting the average noise. After that, the multiple gray values are added together to determine the first energy value.

[0134] d. Determine a second energy value based on the pixels in the second sub-region and the average noise.

[0135] In some embodiments, the average noise can be subtracted from each pixel in the second sub-region to obtain multiple pixels after subtracting the average noise, and then, the gray values of the multiple pixels after subtracting the average noise are added together to obtain the second energy value.

[0136] After determining the average noise, the average noise can also be subtracted from each pixel in the second sub-region to reduce the interference of noise and improve the accuracy of the subsequent determined regional energy concentration value. Then, for all the pixels in the second sub-region after subtracting the average noise, the gray value of each pixel is determined to obtain the gray value of each pixel in the second sub-region. After that, the multiple gray values are added together to determine the second energy value.

[0137] e. Determine the regional energy concentration value based on the first energy value and the second energy value.

[0138] In some embodiments, after obtaining the first energy value and the second energy value, the ratio of the first energy value to the second energy value can be determined as the regional energy concentration value.

[0139] It should be noted that the above description is made by taking the ratio of the first energy value to the second energy value as the regional energy concentration value. Alternatively, in applications, the regional energy concentration value can also be determined by other means. The embodiments of the present application do not limit this.

[0140] For each region of interest, after determining the regional energy concentration value corresponding to each region of interest according to the above steps a - e and obtaining multiple regional energy concentration values, the average value of the multiple regional energy concentration values can be used as the image energy concentration value corresponding to the corresponding reference image.

[0141] Continuing the above description, since the image energy concentration value of each reference image in the multiple reference images is the average value of the regional energy concentration values corresponding to multiple regions of interest in the reference image, therefore, in the subsequent process, determining the target height distance according to the image energy concentration values corresponding to the multiple reference images respectively can improve the accuracy of the determined target height distance, perform more precise focusing, and thus improve the imaging quality when detecting the object to be measured in the subsequent process.

[0142] In some embodiments, in order to quickly determine the target height distance and still be able to obtain the target height distance in the subsequent process, a reference curve graph can be obtained based on multiple image energy concentration values and the height distances corresponding to the multiple reference images respectively; the height distance corresponding to the maximum image energy concentration value in the reference curve graph is determined as the target height distance.

[0143] Based on the above description, it can be determined that the image energy concentration value corresponding to each reference image, and thus, multiple image energy concentration values can be obtained. Moreover, since the multiple reference images are obtained by controlling the shooting of the reference object on the stage at different height distances, it can be known that each reference image in the multiple reference images has a corresponding height distance and image energy concentration value. Therefore, the reference curve graph can be determined according to the image energy concentration values and height distances corresponding to the multiple reference images respectively.

[0144] After obtaining the reference curve graph, the imaging quality corresponding to the point with the highest image energy concentration value in the reference curve graph is the highest. Therefore, the height distance corresponding to the point with the highest image energy concentration value can be determined as the target height distance.

[0145] As an example, please refer to Figure 7 , Figure 7is a schematic diagram of a reference curve graph provided in an embodiment of the present application, wherein the horizontal axis of the reference curve graph is the height distance, and the vertical axis is the image energy concentration value. Figure 7 It can be seen that when the height distance is X, the corresponding image energy concentration value is the highest, and the image energy concentration value is Y. Therefore, it means that when the height distance is X, the corresponding imaging quality is the highest. Therefore, the height distance X can be determined as the target height distance.

[0146] In some embodiments, after determining the target height distance based on the reference images of the reference object at multiple different height distances, the stage can also be controlled to move to a corresponding height in the vertical direction according to the target height distance, and the height value of the upper surface of the reference object when the stage is at this height is obtained as the target height value. The target height value is used to indicate the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position.

[0147] That is to say, the upper surface of the object to be measured and the upper surface of the reference object may not be in the same horizontal plane because the bottom surfaces of the first bearing area and the second bearing area of the stage are not in the same horizontal plane, or because the thickness of the object to be measured is different from the thickness of the reference object. Therefore, after determining the target height, it is also necessary to obtain the height value of the upper surface of the reference object when the stage is at this height as the target height value.

[0148] Therefore, in the subsequent process, the target height value can be determined as the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position, thereby improving the imaging quality when detecting the test area in the object to be tested, and further improving the detection accuracy of the object to be tested.

[0149] In addition, in some embodiments, when the depth of field of the imaging system is greater than the range in which the optimal object distance may drift, or when the optimal object distance is not sensitive to environmental parameters such as temperature, it is possible to avoid focusing, i.e., focal plane calibration, and directly move the object to be tested to the nominal object plane for subsequent testing. In this way, there is no need to perform a focus-seeking process or introduce a reference object, thereby simplifying the process.

[0150] In the embodiment of the present application, by introducing a reference object, and the reference object is located in the second bearing area of the stage, by controlling the relative movement of the stage and the objective lens in the vertical direction, and at each height distance, controlling to photograph the reference object on the stage, a plurality of reference images can be obtained. Then, according to the reference images of the reference object at a plurality of different height distances, the target height distance is determined. That is, the embodiment of the present application performs focus searching based on the reference object. Thus, it can avoid the situation that it is difficult to find a fixed graphic feature as the object for focus imaging due to different graphic types corresponding to different regions of the object to be measured, can improve the accuracy of focus searching, thereby improving the imaging quality of the object to be measured in the subsequent process, and further improving the detection accuracy of the object to be measured; moreover, it can avoid the situation of generating errors due to the undulation of the graphic structure of the object to be measured and the Talbot effect when directly focusing on the object to be measured. In addition, according to a plurality of image energy concentration values and the height distances corresponding to the plurality of reference images respectively, a reference curve graph is determined. Thus, in the subsequent process, the target height distance can be directly determined from the reference curve graph. Moreover, taking the average value of the energy concentration values of a plurality of regions as the image energy concentration value corresponding to the reference image can improve the accuracy of the determined target height distance.

[0151] Figure 8 is a flowchart of another focus searching method provided by the embodiment of the present application, and this method is applied to the processor in the above detection device. Please refer to Figure 8 , and this method includes the following steps:

[0152] Step 801: Control the relative movement of the stage carrying the reference object and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are successively at a plurality of different height distances in the vertical direction.

[0153] In some embodiments, the stage has a first bearing area for bearing the object to be measured; the reference object is the object to be measured. That is to say, focus searching can be directly performed according to the object to be measured. At this time, the stage can have only the first bearing area, and only the first bearing area is used to bear the object to be measured, that is, the object to be measured can also be used as the reference object.

[0154] Step 802: At each height distance, control to photograph the reference object on the stage to obtain the reference image of the reference object at each height distance.

[0155] Step 802 is the same as the above step 202. Please refer to the relevant content of step 202, and details are not described here again.

[0156] Step 803: Based on the reference images of the reference object at multiple different height distances, determine the target height distance, which is used to determine the initial height distance between the stage or the object under test and the objective lens when the object under test is placed on the stage for scanning.

[0157] In some embodiments, for each of the multiple reference images: determine multiple regions of interest in the reference image, then determine the region energy concentration values corresponding to the multiple regions of interest respectively, and based on the multiple region energy concentration values, determine the image energy concentration value corresponding to the reference image. After that, based on the image energy concentration values corresponding to the multiple reference images respectively and the height distances corresponding to the multiple reference images respectively, determine the target height distance.

[0158] Among them, the detailed process of determining the target height distance has been described in detail in Step 203 above, and will not be elaborated here. Please refer to the above content.

[0159] In the embodiments of the present application, by using the object under test as the reference object, without introducing an additional reference object, focusing can be directly performed based on the object under test, and a more targeted focusing process can be carried out for different objects under test. For different objects under test, an accurate target height distance can be determined.

[0160] Figure 9 It is a flowchart of a semiconductor detection method provided by the embodiments of the present application, and this method is applied to the processor in the above detection device. Please refer to Figure 9 , and this method includes the following steps:

[0161] Step 901: Control the stage carrying the object under test and the objective lens to move relative to each other along the scanning direction to reach multiple scanning positions in sequence. The object under test is a semiconductor sample. Among them, control the relative movement of the stage and the objective lens in the vertical direction according to the target height distance so that the upper surface of the region to be measured corresponding to the object under test at the initial scanning position is at the desired height. The target height distance is determined based on any one of the above focusing methods.

[0162] That is to say, the target height distance can be determined by using any one of the above focusing methods. Thus, control can be performed according to the determined target height distance so that the upper surface of the region to be measured corresponding to the object under test at the initial scanning position is at the desired height, that is, at the target height value.

[0163] Step 902: During the scanning process, use the upper surface of the region to be measured corresponding to the object under test at the initial scanning position being at the desired height as the follow - focus zero point to control full - follow focusing on the object under test. After automatic focusing at each scanning position, control imaging of the object under test to obtain the test image of the region to be measured corresponding to the object under test at the current scanning position.

[0164] In some embodiments, the analyte corresponds to different regions to be measured at different scanning positions. By imaging different regions to be measured of the analyte at multiple different scanning positions, the surface scanning and imaging of the analyte can be completed.

[0165] Step 903: Detect the region to be measured based on the image to be measured.

[0166] Exemplarily, defect detection can be performed on the region to be measured based on the image to be measured.

[0167] It can be understood that step 903 can detect the corresponding region to be measured based on the image to be measured by using existing or future detection algorithms.

[0168] In the embodiments of the present application, the target height distance is determined through a reference image, and the expected height of the upper surface of the region to be measured corresponding to the analyte at the initial scanning position is determined according to the target height distance. Then, the expected height is used as the focus tracking zero point to control full-follow focus tracking for the analyte, enabling dynamic adjustment during the scanning process, ensuring accurate and automatic following, and always maintaining the best focal plane.

[0169] This document is described with reference to various exemplary embodiments. However, those skilled in the art will recognize that changes and modifications can be made to the exemplary embodiments without departing from the scope of this document. For example, various operation steps and the components used to perform the operation steps can be implemented in different ways according to a specific application or considering any number of cost functions associated with the operation of the system (e.g., one or more steps can be deleted, modified, or combined into other steps).

[0170] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. Additionally, as understood by those skilled in the art, the principles herein can be embodied in a computer program product on a computer-readable storage medium, which is preloaded with computer-readable program code. Any tangible, non-transitory computer-readable storage medium can be used, including magnetic storage devices (hard disks, floppy disks, etc.), optical storage devices (CD-ROMs, DVDs, Blu-ray discs, etc.), flash memories, and / or the like. These computer program instructions can be loaded onto a general-purpose computer, a special-purpose computer, or other programmable data processing devices to form a machine, such that the instructions executed on the computer or other programmable data processing devices can generate a device for implementing the specified functions. These computer program instructions can also be stored in a computer-readable memory, which can direct the computer or other programmable data processing devices to operate in a specific manner, so that the instructions stored in the computer-readable memory can form a manufactured article, including an implementation device for implementing the specified functions. The computer program instructions can also be loaded onto a computer or other programmable data processing devices, thereby performing a series of operational steps on the computer or other programmable devices to generate a computer-implemented process, such that the instructions executed on the computer or other programmable devices can provide steps for implementing the specified functions.

[0171] Although the principles herein have been shown in various embodiments, many modifications of the structures, arrangements, proportions, elements, materials, and components that are particularly applicable to specific environments and operational requirements can be used without departing from the principles and scope of this disclosure. The above modifications and other changes or revisions will be included within the scope of this document.

[0172] The foregoing detailed description has been described with reference to various embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of this disclosure. Therefore, the consideration of this disclosure will be in an illustrative rather than a restrictive sense, and all such modifications will be included within its scope. Similarly, the advantages, other advantages, and solutions to problems of the various embodiments have been described above. However, the benefits, advantages, solutions to problems, and any elements that can produce these, or solutions that make them more apparent, should not be construed as critical, essential, or necessary. The term "comprising" and any other variants used herein are non-exclusive inclusions, such that a process, method, article, or device that includes a list of elements not only includes those elements, but also includes other elements not expressly listed or not belonging to the process, method, system, article, or device. Additionally, the term "coupled" and any other variants used herein refer to physical connection, electrical connection, magnetic connection, optical connection, communication connection, functional connection, and / or any other connection.

[0173] Those skilled in the art will recognize that many changes may be made to the details of the above-described embodiments without departing from the basic principles of the invention. Thus, the scope of the invention should be determined solely by the claims.

Claims

1. A focusing method, characterized in that, The method includes: Controlling the relative movement in the vertical direction between the stage carrying the reference object and the object to be measured and the objective lens, so that the reference object carried on the stage and the objective lens are successively at multiple different height distances in the vertical direction; wherein, the stage has a first carrying area and a second carrying area, the first carrying area is used to carry the object to be measured, and the second carrying area is used to carry the reference object; At each height distance, controlling the photographing of the reference object on the stage to obtain a reference image of the reference object at each height distance; For each reference image among the multiple reference images: determining multiple regions of interest in the reference image; determining region energy concentration values respectively corresponding to the multiple regions of interest; based on the multiple region energy concentration values, determining the image energy concentration value corresponding to the reference image; according to the multiple image energy concentration values and the height distances respectively corresponding to the multiple reference images, obtaining a reference curve graph; determining the height distance corresponding to the maximum image energy concentration value in the reference curve graph as the target height distance, and the target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

2. The focusing method according to claim 1, wherein After determining the height distance corresponding to the maximum image energy concentration value in the reference curve graph as the target height distance, the method further includes: Controlling the stage to move to the corresponding height in the vertical direction according to the target height distance, and obtaining the height value of the upper surface of the reference object when the stage is at this height as the target height value, and the target height value is used to indicate the height value that the upper surface of the measurement area corresponding to the object to be measured at the initial scanning position needs to be at.

3. The focus finding method according to claim 1, wherein The determining the image energy concentration value corresponding to the reference image based on the multiple region energy concentration values includes: Taking the average value of the multiple region energy concentration values as the image energy concentration value corresponding to the reference image.

4. The focusing method according to claim 1, wherein, The determining the region energy concentration values respectively corresponding to the multiple regions of interest includes: For each region of interest among the multiple regions of interest: Determining the central pixel in the region of interest, and the central pixel is the pixel with the largest gray value in the region of interest; Taking the central pixel as the center, determining a first sub-region, a second sub-region and a third sub-region in the region of interest, the first sub-region is located outside the central pixel, the second sub-region is located outside the first sub-region, and the third sub-region is the other region in the region of interest located outside the second sub-region; Based on the first sub-region, the second sub-region and the third sub-region, determining the corresponding region energy concentration values.

5. The focusing method according to claim 4, wherein The determining the corresponding region energy concentration values based on the first sub-region, the second sub-region and the third sub-region includes: Based on the pixels in the second sub-region and the pixels in the third sub-region, determining the average noise; Determine a plurality of grayscale pixels in the first sub-region, where the plurality of grayscale pixels includes a first pixel with the largest grayscale value in the first sub-region and at least one pixel whose grayscale value is successively smaller than that of the first pixel; Determine a first energy value based on the plurality of grayscale pixels and the average noise; Determine a second energy value based on the pixels in the second sub-region and the average noise; Determine the regional energy concentration value based on the first energy value and the second energy value.

6. The focus finding method according to claim 5, characterized in that, The determining the first energy value based on the plurality of grayscale pixels and the average noise includes: Subtract the average noise from each of the plurality of grayscale pixels to obtain a plurality of grayscale pixels after subtracting the average noise; Add up the grayscale values of the plurality of grayscale pixels after subtracting the average noise to obtain the first energy value.

7. The focusing method according to claim 5 or 6, wherein The determining the second energy value based on the pixels in the second sub-region and the average noise includes: Subtract the average noise from each pixel in the second sub-region to obtain a plurality of pixels after subtracting the average noise; Add up the grayscale values of the plurality of pixels after subtracting the average noise to obtain the second energy value.

8. The focusing method according to claim 7, wherein The determining the regional energy concentration value based on the first energy value and the second energy value includes: Determine the ratio of the first energy value to the second energy value as the regional energy concentration value.

9. The focus finding method according to claim 1, wherein, The reference object is a standard part, and the surface of the standard part has a plurality of circular pits with the same diameter and the same depression distance, and the plurality of circular pits are arranged in a rectangular pattern; or, The reference object is another object to be measured of a different type from the object to be measured located in the first loading area.

10. The focusing method according to claim 1, wherein The bottom surfaces of the first loading area and the second loading area are on the same horizontal plane.

11. A focusing method, characterized in that, The method includes: Control the relative movement in the vertical direction between the stage carrying the reference object and the objective lens, so that the reference object carried on the stage and the objective lens are successively at a plurality of different height distances in the vertical direction; At each height distance, control the shooting of the reference object on the stage to obtain a reference image of the reference object at each height distance; For each of the plurality of reference images: Determine a plurality of regions of interest in the reference image; Determine the regional energy concentration values respectively corresponding to the plurality of regions of interest; Based on the regional energy concentration values respectively corresponding to the plurality of regions of interest, determine the image energy concentration value corresponding to the reference image; Based on the image energy concentration values respectively corresponding to the plurality of reference images and the height distances respectively corresponding to the plurality of reference images, determine the target height distance, and the target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured on the stage; Wherein, the determining the regional energy concentration values respectively corresponding to the plurality of regions of interest includes: For each of the plurality of regions of interest: Determine the central pixel in the region of interest, and the central pixel is the pixel with the largest grayscale value in the region of interest; Taking the central pixel as the center, determine a first sub-region, a second sub-region, and a third sub-region in the region of interest. The first sub-region is located around the central pixel, the second sub-region is located around the first sub-region, and the third sub-region is the other region in the region of interest that is located around the second sub-region; Based on the pixels in the second sub-region and the pixels in the third sub-region, determine the average noise; determine a plurality of gray pixels in the first sub-region, where the plurality of gray pixels includes a first pixel with the largest gray value in the first sub-region and at least one pixel whose gray value is sequentially less than the gray value of the first pixel; based on the plurality of gray pixels and the average noise, determine a first energy value; based on the pixels in the second sub-region and the average noise, determine a second energy value; based on the first energy value and the second energy value, determine the regional energy concentration value.

12. The focus finding method according to claim 11, wherein The stage has a first loading area for loading the object to be measured; the reference object is the object to be measured.

13. A method for detecting a semiconductor, characterized in that, The method includes: Controlling the stage carrying the object to be measured and the objective lens to move relative to each other along the scanning direction to sequentially reach a plurality of scanning positions, where the object to be measured is a semiconductor sample; wherein, according to the target height distance, controlling the stage and the objective lens to move relative to each other in the vertical direction so that the upper surface of the region to be measured corresponding to the object to be measured at the initial scanning position is at the desired height, and the target height distance is determined based on the focusing method according to any one of claims 1 to 12; During the scanning process, taking the upper surface of the region to be measured corresponding to the object to be measured at the initial scanning position being at the desired height as the follow-focus zero point, controlling full follow-focus on the object to be measured, and after automatic focusing at each scanning position, controlling imaging of the object to be measured to obtain the measured image of the region to be measured corresponding to the object to be measured at the current scanning position; Detect the region to be measured based on the measured image.

14. A detection device, characterized in that, Including: A stage having a first loading area for loading the object to be measured, and the stage also has a second loading area for loading the reference object; An imaging optical path assembly including a detection sensor and an objective lens; the imaging optical path assembly is used to optically image the object to be measured and the reference object on the stage through the objective lens, and transmit the imaged optical signal to the detection sensor, and the detection sensor is used to convert the optical signal into an electrical signal, so as to obtain the measured image of the object to be measured and the reference image of the reference object; A driving assembly for driving the stage and the objective lens to move relative to each other; A processor for executing the method according to any one of claims 1 to 13.

15. A computer-readable storage medium, characterized in that, A computer program is stored on the medium, and the computer program can be executed by the processor to implement the method according to any one of claims 1 to 13.

Images