WO2024022006A1

WO2024022006A1 - Calibration system, measurement and calibration tool, and calibration method

Info

Publication number: WO2024022006A1
Application number: PCT/CN2023/104149
Authority: WO
Inventors: 劳大鹏; 王犇; 邵永胜; 李强; 杨荣
Original assignee: 华为技术有限公司
Priority date: 2022-07-28
Filing date: 2023-06-29
Publication date: 2024-02-01

Abstract

A calibration system, a measurement and calibration tool (20), and a calibration method. The calibration system comprises: a measurement frame (101), the measurement and calibration tool (20), and a displacement table. The calibration system is used for calibrating the relative positions of a lens group (102) to the measurement and calibration tool (20) and the displacement table; in the process of calibrating the measurement and calibration tool (20), the measurement frame (101) is connected to the lens group (102); the measurement and calibration tool (20) is further mounted on the measurement frame (101); the lens group (102) is provided with at least two first marks (M1). The measurement and calibration tool (20) comprises: a carrier disc (201), a reference structure (202) fixed on the carrier disc (201), and an adjustment structure (203) connected to the carrier disc (201). The carrier disc (201) is provided with at least two second marks (M2). The adjustment structure (203) is used for rotating the carrier disc (201) according to position information of the lens group (102) and position information of the carrier disc (201) so as to adjust a first angle between the lens group (102) and the reference structure (202), the first angle being used for describing the relative position relationship between the lens group (102) and the reference structure (202) in a direction perpendicular to the carrier disc (201), so that the alignment between the lens group (102) and the displacement table can be realized.

Description

Calibration system, calibration tool and calibration method

Cross-references to related applications

This application claims priority to a Chinese patent application filed with the China Patent Office on July 28, 2022, with application number 202210899008.0 and application title "A calibration system, calibration tool and calibration method", the entire content of which is incorporated by reference. in this application.

Technical field

The present application relates to the field of semiconductor manufacturing technology, and in particular, to a calibration system, a calibration tool and a calibration method.

Background technique

In large-scale integrated circuit processing technology, etching process is one of the important key technologies. Among them, charged particle beam etching equipment has higher etching accuracy because the wavelength of electrons is shorter, which is an important technical route. Moreover, when a charged particle beam is incident on a material, different material compositions and morphological characteristics will produce different backscattered electrons, secondary electrons and characteristic X-ray distributions. Therefore, the detected backscattered electrons, secondary electrons and The characteristic X-ray distribution infers the composition and morphological characteristics of the sample. In the production process of large-scale integrated circuits, charged particle beam inspection equipment is widely used in defect detection and critical dimension measurement of samples.

For charged particle beam etching equipment and charged particle beam detection equipment, if the lens group is misaligned with the displacement stage that carries the wafer, the position error of the displacement stage will be large, which will cause the image to be tilted. Figure 1 is a schematic diagram of the image when the position error of the displacement stage is large. As shown in Figure 1, if the position error of the displacement stage is small, the image should be multiple rectangles. Because the position error between the displacement stages is large, it will The image is tilted, and the actual image is multiple parallelograms, resulting in a reduction in etching accuracy or detection accuracy. Therefore, in order to reduce the position error of the displacement stage and improve the etching accuracy or detection accuracy, the lens group and the displacement stage need to be aligned.

Contents of the invention

In order to align the lens group with the displacement stage to reduce the position error of the displacement stage to improve etching accuracy or detection accuracy. Embodiments of the present application provide a calibration system, a calibration tool and a calibration method.

In the first aspect, embodiments of the present application provide a calibration system, which can be applied to semiconductor etching equipment or semiconductor detection equipment, and can also be applied to other equipment related to charged particle beams, which is not limited here.

The calibration system provided by the embodiment of the present application may include: a measurement frame, a calibration tool, and a displacement stage. The calibration system is used to calibrate the relative positions of the lens group, measurement and calibration tools, and displacement stages. During the process of calibrating the measurement and calibration tools, the measurement frame is connected to the lens group. The measurement frame is also equipped with measurement and calibration tools. The lens group is located in the measurement frame. On the side away from the calibration tool, the lens group is provided with at least two first marks, and the first marks are used to indicate position information of the lens group. The calibration tool may include: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate. The bearing plate is provided with at least two second marks, and the second marks are used to indicate position information of the bearing plate. . The adjustment structure is used to rotate the carrier plate according to the position information of the lens group and the position information of the carrier plate, and adjust the first angle between the lens group and the reference structure. The first angle is used to describe the position of the lens group and the reference structure perpendicular to the carrier. Relative positional relationship in disk direction. The lens group may include an optical lens group or an electronic lens group, and the lens group may serve to converge or diffuse the light beam or charged particle beam, adjust the path of the light beam or charged particle beam, etc.

In the calibration system provided by the embodiment of the present application, at least two first marks are set on the lens group and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement can be The calibration tool is installed on the side of the measurement frame away from the lens group. The adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure, so that the calibration tool can be calibrated. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor inspection equipment.

In some embodiments of the present application, the position information of the lens group can be determined according to each first mark in the lens group, and the position information of the carrier tray can be determined according to each second mark in the carrier tray. According to the relative positional relationship between each first mark in the lens group and each second mark in the carrier tray, and the relative positional relationship between each second mark in the carrier tray and the reference structure, the third relationship between the lens group and the reference structure can be determined. An angle. According to the first angle and the preset first threshold, the angle adjustment value can be determined. According to the determined angle adjustment value, the adjustment structure is controlled to drive the bearing plate to rotate to adjust the first angle between the lens group and the reference structure until the adjustment The final first angle is less than the preset first threshold. The above-mentioned first threshold can be set according to the stroke capability of the displacement stage. For example, the above-mentioned first threshold can be set to 500 urad.

The calibration system in the embodiment of the present application may also include: a position sensor located on the side of the lens group away from the measurement frame, and a position sensor located on the side of the lens group away from the measurement frame. The charged particle beam source on the side of the mirror assembly facing away from the displacement stage. The displacement stage is used to carry the wafers to be etched or inspected. The displacement stage can be moved by the machine and other components, so that the charged particle beam emitted from the charged particle beam source can pass through the lens group and be directed to the wafer carried by the displacement stage. on the wafer to achieve charged particle beam etching or charged particle beam detection functions.

After the calibration system calibrates the calibration tool, the calibration tool can be used to calibrate the signal emission direction of the position sensor. Specifically, the position sensor can be fixed on the side of the measurement frame away from the lens group, and the position sensor is used when When an angle is smaller than the first threshold, the position information of the reference structure is obtained, where the position information can be used to calibrate the displacement stage when the displacement stage is installed after the calibration tool is removed. After the displacement stage is calibrated, the position sensor is also used to detect the position of the displacement stage, so that the position of the displacement stage can be adjusted through the detection data fed back by the position sensor, so that the charged particle beam emitted from the charged particle beam source can be directed towards the bearing of the displacement stage. on the wafer.

In this embodiment of the present application, the reference structure may be a multifaceted mirror tooling (MMT) in the shape of a cuboid. That is to say, any two adjacent sides of the reference structure are perpendicular to each other, and each side of the reference structure is a reflective surface. In this way, the reference structure can be used as an orientation reference in the Cartesian coordinate system. For example, the lens group and After the reference structure is aligned, the reflective surface of the reference structure can be used to align the orientation of the position sensor.

During the use of semiconductor etching equipment or semiconductor testing equipment, if the error between the signal emission direction of the position sensor and the moving direction of the displacement stage is too large, the positioning accuracy of the displacement stage will decrease, which will cause the semiconductor etching equipment to be damaged. The corrosion accuracy or the detection accuracy of the semiconductor inspection equipment is reduced. In the embodiment of the present application, by setting up a calibration tool, the lens group can be aligned with the reference structure. After that, the reflective surface of the reference structure can be used to adjust the signal emission direction of the position sensor. Then, the determined signal emission direction is adjusted to the displacement stage. The moving direction can make the error between the signal emission direction of the position sensor and the moving direction of the displacement stage smaller, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor detection equipment.

In a possible implementation, the first mark may be located on the surface of the side of the lens group facing the measurement frame, and the second mark may be located on the surface of the side of the carrier plate where the reference structure is provided. In this way, the relative positional relationship between each first mark and each second mark can be determined more easily. During the calibration process of the calibration system, the measurement and calibration tool is installed on the side of the measurement frame away from the lens group, and the side of the measurement and calibration tool with the reference structure faces the measurement frame. The first mark is arranged on the surface of the lens group facing the measurement frame, and the second mark is arranged on the surface of the bearing plate on the side where the reference structure is provided, so that each first mark and each second mark can be arranged oppositely. The calibration system in the embodiment of the present application may further include: an image collector, the image collector is used to acquire at least one image, the image includes at least one first marked image and/or at least one second marked image, where at least one of the above The position information of each image and the corresponding image collector is used to determine the relative positional relationship between the lens group and the carrier plate. Therefore, according to the image acquired by the image collector, the relative positional relationship between each first mark and each second mark can be determined. In one possible implementation, the image collector can be disposed between the lens group and the calibration tool. In another possible implementation, the position of the carrier plate corresponding to each second mark can be disposed in a light-transmissive manner, The bearing plate can be made of transparent material, such as crystallized glass material, or it can be hollowed out at a position corresponding to the second mark on the bearing plate. In this way, the image collector can be placed on the side of the calibration tool away from the lens group. The image collector can acquire at least one image through a light-transmissive position on the carrier plate, and the image includes at least one image of the first mark and at least one image of the second mark. Of course, in some cases, the first mark and the second mark can also be set at other positions, as long as the relative positional relationship between each first mark and each second mark can be determined. The first mark and the second mark are not discussed here. position is limited.

In a possible implementation, the first marks on the lens group can be arranged in a row, the second marks on the carrier plate can be arranged in a row, and the arrangement directions of the first marks and the second marks can be consistent. During the calibration process, in order to determine the relative positional relationship between each first mark and each second mark, an image collector can be used to obtain images of each first mark and each second mark respectively, and compare each first mark with each third mark. The two markers are arranged in the same arrangement, which makes it easier for the image collector to sequentially acquire images of each first marker and images of each second marker.

In a possible implementation, the first marks on the lens group can be arranged at equal intervals, and the second marks on the carrier plate can be arranged at equal intervals. This facilitates calculation of the relative positional relationship between each first mark and each second mark, reduces the amount of calculation, and increases the calculation speed. Optionally, the distance between two adjacent first marks may be consistent with the distance between two adjacent second marks. Of course, the first marks on the lens group can also be arranged in other ways, and the second marks on the carrier plate can also be arranged in other ways, which are not limited here.

In some embodiments of the present application, the adjustment structure may include: a turntable fixedly connected to the bearing plate, and screws located on the side of the turntable for driving the turntable to rotate. Saw teeth can be provided on the side of the turntable, and threads matching the saw teeth can be provided on the screws. The saw teeth on the turntable can engage with the threads on the screws, so that the turntable can be driven to rotate by turning the screws. Since the turntable is fixedly connected to the bearing plate, during the rotation of the turntable, the bearing plate can be driven to rotate, so that the first angle between the lens group and the reference structure can be adjusted. Wherein, the pitch between the threads of the screw and the radius of the turntable can be determined according to the adjustment accuracy of the first angle.

In other embodiments of the present application, the adjustment structure may include: a first top wire and a second top wire. This can be achieved by rotating the first jackscrew and /or a second top screw to drive the bearing plate to rotate, so that the first angle between the lens group and the reference structure can be adjusted.

In this embodiment of the present application, the position sensor may include: a first position sensor and a second position sensor. The first position sensor is used to obtain the position of the reference structure in the first direction. The second position sensor is used to obtain the position of the reference structure in the second direction. As for the position of the direction, both the first direction and the second direction are parallel to the surface of the bearing plate, and the first direction and the second direction cross each other. For example, the first direction and the second direction may be perpendicular to each other. The displacement stage can be calibrated based on the obtained positions of the reference structure in the first direction and the second direction, after removing the calibration tool and installing the displacement stage. The first position sensor and the second position sensor can be a laser interferometer or a laser range finder. By emitting laser light to the displacement stage and receiving the reflected laser light, the coordinates of the displacement stage can be easily determined.

In a second aspect, embodiments of the present application also provide a test and calibration tool. The test and calibration tool may include: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate. The bearing plate is provided with at least Two second marks, the second marks are used to indicate the position information of the carrier disk. The adjustment structure is used to rotate the carrier plate according to the position information of the lens group and the position information of the carrier plate, and adjust the first angle between the lens group and the reference structure. The first angle is used to describe the position of the lens group and the reference structure perpendicular to the carrier. Relative positional relationship in disk direction.

In the embodiment of the present application, at least two first marks are set on the lens group and at least two second marks are set on the bearing plate of the test and calibration tool. In this way, before installing the displacement stage, the test and calibration tool can be installed on the The side of the measurement frame facing away from the lens group drives the bearing plate to rotate through the adjustment structure to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

For the specific implementation of the test and calibration tool in the second aspect of this application, reference can be made to the specific implementation of the test and calibration tool in the first aspect, and the repeated parts will not be described again.

In a third aspect, embodiments of the present application also provide a calibration method for a calibration system. The calibration method provided by the embodiment of the present application may include:

Install the measurement frame, the lens group and the calibration tool, wherein the calibration tool is installed on the side of the measurement frame away from the lens group; wherein the lens group is provided with at least two first marks, and the first marks are used to indicate the position of the lens group information; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks, and the second marks are used to indicate the position of the bearing plate Information; obtain the relative positional relationship between the lens group and the carrier plate; determine the first angle between the lens group and the reference structure based on the relative positional relationship between the lens group and the carrier plate. The first angle is used to describe the vertical position between the lens group and the reference structure. The relative position relationship in the direction of the bearing plate; rotating the bearing plate through the adjustment structure until the first angle is smaller than the preset first threshold.

In the calibration method provided by the embodiment of the present application, at least two first marks are set on the lens group, and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement and calibration can be The tool is installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

In this embodiment of the present application, the above-mentioned acquisition of the relative positional relationship between the lens group and the carrier plate may include:

At least one image is acquired by the image collector, and the image includes at least one image of a first mark and/or an image of at least one second mark. The image collector can be any image collector capable of image collection, such as a camera or a video camera. Then, based on the positional relationship between the above-mentioned at least one image and the corresponding image collector, the relative positional relationship between the lens group and the carrier plate is determined. In the embodiment of the present application, optical means are used to obtain the image of the first mark and the image of the second mark, so that the relative positional relationship between the lens group and the carrier plate can be more easily determined, and the first angle can subsequently be determined based on the relative positional relationship.

In a possible embodiment, the image collector may include: a first image collector and a second image collector. The above-described acquisition of at least one image through the image collector may include:

Set linear guide rails between the lens group and the calibration tool;

The first image collector and the second image collector are installed on the linear guide rail. The first image collector and the second image collector can slide along the linear guide rail, and the relative positions of the first image collector and the second image collector are Remaining unchanged, the collection surface of the first image collector faces the lens group, and the collection surface of the second image collector faces the calibration tool. That is to say, two image collectors are used to collect images of the first mark and the second mark respectively, wherein the first image collector is used to collect the image of the first mark, and the second image collector is used to collect the image of the second mark;

Control the first image collector and the second image collector to move along the linear track at the same time, so that the first image collector sequentially collects at least two images of each first mark, and the second image collector sequentially collects at least two images of each second mark. Two images. The first image collector and the second image collector can move synchronously, that is, the relative positions of the first image collector and the second image collector remain unchanged, and the first image collector acquires at least one image of the first mark each time, The second image collector acquires at least one image of the second marker at a time. In the embodiment of this application, Two image collectors are used to collect the images of the first mark and the second mark respectively, and the acquisition speed is faster.

After that, remove the linear guide rail, the first image collector and the second image collector.

In another possible embodiment, the position of the carrier plate corresponding to the second mark can be set in a light-transmitting setting, that is, the bearing plate has a light-transmitting area at the position of the second mark. The bearing plate can be made of a transparent material, for example Crystallized glass material is used, or the position of the bearing plate corresponding to the second mark can be hollowed out. In this way, the image collector (ie, the third image collector) can be provided only on the side of the calibration tool away from the lens group. The three image collectors can acquire images of the first mark and the second mark through a light-transmitting area in the carrier plate.

The above-mentioned acquisition of at least one image through the image collector may include:

Set a linear guide rail on the side of the measurement and calibration tool away from the lens group; install the third image collector on the linear guide rail, and the third image collector can slide along the linear guide rail; the collection surface of the third image collector faces the measurement and calibration tool ; Control the third image collector to move along the linear guide rail and acquire at least one image, the image including at least one first mark and at least one second mark. That is, only one image collector can be used to simultaneously capture images of the first mark and the second mark. During the acquisition process of the third image collector, the height of the calibration tool can be adjusted so that the first mark and the second mark are within the depth of field of the third image collector.

After that, remove the linear guide and the third image collector.

In a possible implementation, the first marks on the lens group can be arranged in a row, and the second marks on the carrier plate can be arranged in a row, which can facilitate the image collector to collect the first marks and the second marks. Image. Optionally, the arrangement directions of each first mark and each second mark can be consistent, so that the first mark and the second mark can more easily fall into the collection range of the image collector.

In a possible implementation, the adjustment structure may include: a turntable fixedly connected to the bearing plate, and screws located on the side of the turntable for driving the turntable to rotate.

The above-mentioned rotation of the bearing plate through the adjustment structure may include:

The turntable is driven to rotate by rotating the screw to drive the bearing plate to rotate.

In the embodiment of the present application, saw teeth can be provided on the side of the turntable, and threads matching the saw teeth can be provided on the screws. The saw teeth on the turntable can engage with the threads on the screws, so that the turntable can be driven to rotate by turning the screws. Since the turntable is fixedly connected to the bearing plate, during the rotation of the turntable, the bearing plate can be driven to rotate, so that the first angle between the lens group and the reference structure can be adjusted. Wherein, the pitch between the threads of the screw and the radius of the turntable can be determined according to the adjustment accuracy of the first angle.

In another possible implementation, the adjustment structure may include: a first top wire and a second top wire.

By rotating the first jackscrew and/or the second jackscrew, the bearing plate is driven to rotate.

In one possible implementation, the reference structure can be a polygonal mirror in the shape of a cuboid. That is to say, any two adjacent sides of the reference structure are perpendicular to each other, and each side of the reference structure is a reflecting surface. In this way, the reference structure can be used as an orientation reference in the Cartesian coordinate system. The reference structure may include: adjacent first reflective surfaces and second reflective surfaces. The position sensor may include: a first position sensor for detecting the position of the displacement stage in the first direction and a second position sensor for detecting the position of the displacement stage in the second direction.

The above calibration methods can also include:

Install the first position sensor and the second position sensor on the measurement frame; adjust the first position sensor so that the signal emission direction of the first position sensor is perpendicular to the first reflective surface of the reference structure; adjust the second position sensor so that The signal emission direction of the second position sensor is perpendicular to the second reflective surface of the reference structure.

In the embodiment of the present application, since the reference structure can be used as an azimuth reference in the Cartesian coordinate system, the first position sensor and the second position sensor can be adjusted according to the orientation of the reflective surface of the reference structure so that the signal emission direction of the first position sensor Perpendicular to the first reflective surface, the signal emission direction of the second position sensor is perpendicular to the second reflective surface. In practical applications, the direction perpendicular to the first reflective surface can be used as the first direction, and the direction perpendicular to the second reflective surface can be used as the second direction. In this way, the first position sensor can detect the movement of the displacement stage in the first direction. position, the second position sensor can detect the position of the displacement stage in the second direction, so that the position of the displacement stage can be accurately positioned.

In some embodiments of the present application, the first position sensor and the second position sensor may be laser interferometers or laser rangefinders. The first position sensor can be controlled to emit laser light toward the reference structure in the first direction, and receive the reflected light from the reflective surface of the reference structure, and read the spot overlap intensity of the emitted light and the reflected light in the first direction. When the spot overlap intensity reaches At the maximum value, the signal emission direction of the first position sensor is approximately perpendicular to the first reflective surface. Similarly, the second position sensor can be controlled to emit laser light toward the reference structure in the second direction and receive the reflected light from the reflective surface of the reference structure. By reading the spot overlap intensity of the emitted light and the reflected light in the second direction, when the When the light spot overlap intensity reaches the maximum value, the signal emission direction of the second position sensor is approximately perpendicular to the second reflective surface.

In the calibration method provided by the embodiment of the present application, the lens group can be aligned with the reference structure by setting up a calibration tool. After that, the reflective surface of the reference structure can be used to adjust the signal emission direction of the position sensor. Subsequently, the signal output of the position sensor can be adjusted according to the signal of the position sensor. The output direction is adjusted to adjust the displacement stage so that the moving direction of the displacement stage is basically consistent with the direction of the signal output direction of the position sensor, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor detection equipment. Moreover, in the calibration method provided by the embodiment of the present application, there is no need to adjust the connection relationship between the lens group and the measurement frame, which can effectively improve the connection stiffness of the lens group and the measurement frame and reduce the dynamic error of the system. There is no need to use a micro-moving stage and other structures in the lens group, and the lens group and the displacement stage can be quickly and accurately compared. The calibration method is highly flexible.

In the fourth aspect, the embodiment of the present application also provides another calibration method for the calibration system. The calibration method provided by the embodiment of the present application may include:

The measurement frame and the calibration tool are installed according to the lens group, wherein the measurement and calibration tool is installed on the side of the measurement frame away from the lens group; wherein the lens group is provided with at least two first marks, and the first marks are used to indicate the position of the lens group. information; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks, and the second marks are used to indicate the position of the bearing plate Information; obtain the relative positional relationship between the lens group and the carrier plate; determine the first angle between the lens group and the reference structure based on the relative positional relationship between the lens group and the carrier plate. The first angle is used to describe the vertical position between the lens group and the reference structure. The relative position relationship in the direction of the bearing plate; adjust the first angle by rotating the bearing plate through the adjustment structure; when the first angle is less than the preset first threshold, obtain the position information of the reference structure and remove the calibration tool; according to the Position information to install and adjust the stage.

In the calibration method provided by the embodiment of the present application, at least two first marks are set on the lens group, and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement and calibration can be The tool is installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Then, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

For the specific implementation of the calibration method in the fourth aspect of the present application, reference may be made to the specific implementation of the calibration method in the third aspect, and repeated details will not be described again.

Description of drawings

Figure 1 is a schematic diagram of the image when the position error of the displacement stage is large;

Figure 2 is a schematic diagram of the calibration system provided by the embodiment of the present application during the calibration process;

Figure 3 is a schematic structural diagram of the test and calibration tool in the embodiment of the present application;

Figure 4 is a schematic structural diagram of the calibration system provided by the embodiment of the present application after calibration;

Figure 5 is a top view or side view of the displacement stage in the embodiment of the present application;

Figure 6 is a bottom view of the lens group in the embodiment of the present application;

Figure 7 is a schematic diagram of the distribution of each first mark and each second mark;

Figure 8 is another structural representation of the calibration tool in the embodiment of the present application;

Figure 9 is a schematic diagram of the calibration process of the position sensor in the embodiment of the present application;

Figure 10 is a schematic diagram of the calibration process of the displacement stage in the embodiment of the present application;

Figure 11 is a schematic flow chart of the calibration method provided by the embodiment of the present application;

Figure 12 is a schematic diagram of the image acquisition process in the embodiment of the present application;

Figure 13 is another schematic diagram of the image acquisition process in the embodiment of the present application;

Figure 14 is another schematic flow chart of the calibration method provided by the embodiment of the present application.

Reference signs:
101-Measurement frame; 102-Lens group; 103-Position sensor; 103a-First position sensor; 103b-Second position sensor; 104-
Displacement stage; 20-measuring and calibration tools; 201-carrying plate; 202-reference structure; 203-adjustment structure; 203a-turntable; 203b-screw; 203c-first jackscrew; 203d-second jackscrew; 21-bracket; 22-pillar; 401-linear guide; 402-first image collector; 403-second image collector; 404-third image collector; x-first direction; y-second direction; z-third direction ;M1-first mark;M2-second mark.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in conjunction with the accompanying drawings.

It should be noted that the same reference numerals in the drawings of the present application represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in this application are all explained by taking the accompanying drawings as examples, but they can be changed as needed, and all changes are included in the protection scope of this application. The drawings in this application are only used to illustrate relative positional relationships and do not represent true proportions.

In order to align the lens group with the displacement stage to reduce the position error of the displacement stage to improve etching accuracy or detection accuracy. Embodiments of the present application provide a calibration system, a calibration tool and a calibration method. Wherein, the calibration system can be applied to semiconductor etching equipment or semiconductor detection equipment. For example, semiconductor etching equipment includes etching equipment and charged particle beam etching equipment, and semiconductor detection equipment includes electron beam detection equipment and scanning electron microscopes. There are no limitations here.

In practical applications, taking charged particle beam etching equipment or charged particle beam detection equipment as an example, for single column or single beam (i.e., single charged particle beam) equipment, the position accuracy of the displacement stage is relatively low, and through the mechanical structure It is possible to adjust the lens group to align with the displacement stage. For multi-charged particle beam etching equipment, since the multi-charged particle beam etching equipment does not have a mask and the lens group is heavy, the alignment of the multi-charged particle beam etching equipment is difficult and cannot be based on The position of the displacement stage adjusts the entire lens group, and alignment between the lens group and the displacement stage cannot be achieved through mechanical processing alone. For multi-charged particle beam detection equipment, in some application scenarios it is necessary to stitch images of each charged particle beam. The position accuracy of the displacement stage is relatively high, and the combination of the lens group and the displacement stage cannot be achieved through mechanical processing alone. alignment between. The calibration system provided by the embodiments of the present application can be applied to equipment such as multi-charged particle beam etching equipment and multi-charged particle beam detection equipment to achieve alignment between the lens group and the displacement stage.

Figure 2 is a schematic diagram of the calibration system provided by the embodiment of the present application during the calibration process. Figure 3 is a schematic structural diagram of the calibration tool in the embodiment of the present application. As shown in Figures 2 and 3, the calibration system provided by the embodiment of the present application It may include: measurement frame 101, calibration tool 20 and displacement stage. The calibration system is used to calibrate the relative positional relationship between the lens group 102, the measurement and calibration tool 20, and the displacement stage. During the process of calibrating the measurement and calibration tool 20, the measurement frame 101 is connected to the lens group 102, and the measurement frame 101 is also equipped with a measurement and calibration device. The tool 20 and the lens group 102 are located on the side of the measurement frame 101 away from the calibration tool 20 . The lens group 102 is provided with at least two first marks (not shown in the figure), and the first marks are used to indicate position information of the lens group 102 .

Among them, the measurement frame 101 can play a role in fixing and supporting other components, and multiple components such as the lens group 102 in the semiconductor etching equipment (or semiconductor testing equipment) can be fixed on the measurement frame 101 . The lens group 102 can include an optical lens group or an electronic lens group, wherein the optical lens group can converge or diffuse the beam, adjust the path of the beam, etc.; the electronic lens group can converge or diffuse the charged particle beam, and adjust the charged particle beam. path etc.

The calibration tool 20 may include: a bearing plate 201, a reference structure 202 fixed on the bearing plate 201, and an adjustment structure 203 connected to the bearing plate 201. The bearing plate 201 is provided with at least two second marks M2. M2 is used to indicate the position information of the carrier tray 201 . Among them, the adjustment structure 203 is used to rotate the carrier tray 201 according to the position information of the lens group 102 and the position information of the carrier tray 201, and adjust the first angle between the lens group 102 and the reference structure 202. The first angle is used to describe the lens group 102 The relative position relationship with the reference structure 202 in the direction perpendicular to the carrier plate 201.

In the calibration system provided by the embodiment of the present application, at least two first marks are set on the lens group and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement can be The calibration tool is installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor inspection equipment.

Continuing to refer to FIGS. 2 and 3 , during specific implementation, the calibration tool 20 may also include: a bracket 21 and a plurality of pillars 22 located on the bracket 21 . The bearing plate 201 , the reference structure 202 and the adjustment structure 203 can be disposed on the bracket 21 . During the calibration process of the calibration system, the calibration tool 20 can be fixedly connected to the measurement frame 101 through the support 22 .

As shown in Figure 2, during specific implementation, a rectangular coordinate system can be used to identify the positions of each component in the calibration system, where the first direction x and the second direction y are both parallel to the bearing plate in the measurement and calibration tool 20, And the first direction x and the second direction y cross each other. For example, the first direction x and the second direction y can be perpendicular to each other, and the third direction z is perpendicular to the bearing plate in the calibration tool 20 . Rx is the angle obtained by rotating around the first direction x, Ry is the angle obtained by rotating around the second direction y, and Rz is the angle obtained by rotating around the third direction z. In some embodiments of the present application, the above-mentioned first angle may be an angle obtained by rotating the lens group 102 and the reference structure 202 around the third direction z.

In specific implementation, the position information of the lens group 102 can be determined according to each first mark in the lens group 102, and the position information of the carrier tray 201 can be determined according to each second mark M2 in the carrier tray 201. According to the relative positional relationship between each first mark in the lens group 102 and each second mark M2 in the carrier tray 201, and the relative positional relationship between each second mark M2 in the carrier tray 201 and the reference structure 202, the lens group 102 can be determined. A first angle with reference structure 202 . According to the first angle and the preset first threshold, the angle adjustment value can be determined. According to the determined angle adjustment value, the adjustment structure 203 is controlled to drive the bearing plate 201 to rotate to adjust the first angle between the lens group 102 and the reference structure 202. angle until the adjusted first angle is less than the preset first threshold. The above-mentioned first threshold can be set according to the stroke capability of the displacement stage 104. For example, the above-mentioned first threshold can be set to 500 urad.

Figure 4 is a schematic structural diagram of the calibration system after calibration provided in the embodiment of the present application. As shown in Figure 4, the calibration in the embodiment of the present application The system may also include: a position sensor 103. The position sensor 103 may be located on the side of the lens group 102 away from the measurement frame 101. In a possible implementation, in order to implement the charged particle beam etching or charged particle beam detection function, the lens is A charged particle beam source (not shown in the figure) may also be provided on the side of the group 102 away from the displacement stage 104 . The displacement stage 104 is used to carry the wafer to be etched or to be inspected. The displacement stage 104 can be moved by components such as the machine platform, so that the charged particle beam emitted from the charged particle beam source can be directed to the displacement through the lens group 102 The stage 104 carries the wafer.

After the calibration system calibrates the calibration tool, the calibration tool can be used to calibrate the signal emission direction of the position sensor 103. Specifically, the position sensor 103 can be fixed on the side of the measurement frame 101 away from the lens group 102. The position sensor 103 is used to obtain the position information of the reference structure when the first angle is less than the first threshold, wherein the position information can be used to calibrate the displacement stage 104 when the displacement stage 104 is installed after the calibration tool is removed. After the displacement stage 104 is calibrated, the position sensor 103 is also used to detect the position of the displacement stage 104, so that the position of the displacement stage 104 can be adjusted through the detection data fed back by the position sensor 103, so that the charged particle beam emitted from the charged particle beam source can onto the wafer carried by the displacement stage 104 .

In the embodiment of the present application, as shown in FIG. 3 , the reference structure 202 may be a multifaceted mirror tooling (MMT) in the shape of a cuboid. That is to say, any two adjacent sides of the reference structure 202 are perpendicular to each other, and each side of the reference structure 202 is a reflective surface. In this way, the reference structure 202 can be used as an orientation reference in the rectangular coordinate system. For example, After the lens group is aligned with the reference structure 202, the reflective surface of the reference structure 202 can be used to align the orientation of the position sensor.

Figure 5 is a top view or side view of the displacement stage in the embodiment of the present application. As shown in Figure 5, the dotted line F1 can represent the signal emission direction of the position sensor, and the dotted arrow F2 can represent the moving direction of the displacement stage 104. If the error between the signal emission direction of the position sensor and the moving direction of the displacement stage 104 is too large, the positioning accuracy of the displacement stage 104 will be reduced, and the etching accuracy of the semiconductor etching equipment will be reduced or the detection accuracy of the semiconductor detection equipment will be reduced. In the embodiment of the present application, by setting up a calibration tool, the lens group can be aligned with the reference structure. After that, the reflective surface of the reference structure can be used to adjust the signal emission direction of the position sensor. Then, the determined signal emission direction is adjusted to the displacement stage. Therefore, the error between the signal emission direction of the position sensor and the moving direction of the displacement stage 104 can be smaller, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor detection equipment.

In specific implementation, continuing to refer to FIGS. 2 to 4 , the first mark may be located on the surface of the lens group 102 facing the measurement frame 101 , and the second mark M2 may be located on the surface of the carrier plate 201 on the side where the reference structure 202 is provided. In this way, the relative positional relationship between each first mark and each second mark M2 can be more easily determined. During the calibration process of the calibration system, the calibration tool 20 is installed on the side of the measurement frame 101 away from the lens group 102 , and the side of the calibration tool 20 with the reference structure 202 faces the measurement frame 101 . The first mark is arranged on the surface of the lens group 102 facing the measurement frame 101, and the second mark M2 is arranged on the surface of the bearing plate 201 on the side where the reference structure 202 is provided, so that each first mark and each second mark M2 can be opposite to each other. set up. During specific implementation, the calibration system in the embodiment of the present application may also include: an image collector, the image collector is used to acquire at least one image, the image includes at least one first marked image and/or at least one second mark M2 The above-mentioned at least one image and the position information of the corresponding image collector are used to determine the relative positional relationship between the lens group and the carrier plate. Therefore, according to the image acquired by the image collector, the relative positional relationship between each first mark and each second mark M2 can be determined. In one possible implementation, the image collector can be disposed between the lens group 102 and the calibration tool 20 . In another possible implementation, the position of the bearing plate 201 corresponding to each second mark M2 can be Light-transmitting setting, the carrier tray 201 can be made of transparent material, such as crystallized glass material, or it can be hollowed out at the position of the carrier tray 201 corresponding to the second mark M2, so that the image collector can be installed on the carrier tray 201 Below and on the side away from the lens group 102, the image collector can acquire at least one image through a light-transmissive position on the carrier plate, and the image includes at least one image of the first mark and at least one image of the second mark. Of course, in some cases, the first mark and the second mark can also be set at other positions, as long as the relative positional relationship between each first mark and each second mark can be determined. The first mark and the second mark are not discussed here. position is limited.

Figure 6 is a bottom view of the lens group in the embodiment of the present application (that is, a schematic view of the side of the lens group facing the measurement frame). As shown in Figure 6, the first mark M1 can be disposed on the surface of the lens group 102 facing the measurement frame 101. , for example, the first mark M1 may be set on the projection objective lens at the bottom of the lens group 102 . The position indicated by the circle P in Figure 6 is the area where the charged particle beam passes. When setting the first mark M1, the position of the first mark M1 needs to be positioned away from the area indicated by the circle P, which the charged particle beam passes through. During the processing of the lens group 102, laser etching or other means can be used to form at least two first marks M1 on the lens group 102, and then the positions of the first marks M1 can be measured and calibrated through an optical microscope or an electron microscope. The position of each first mark M1 on the lens group 102 is known, so that the position of the first mark M1 can be used to indicate the position of the lens group 102 .

Referring to FIG. 3 , during the processing of the calibration tool 20 , at least two second marks M2 can be formed on the bearing plate 201 , and the position of each second mark M2 is calibrated through optical detection or other means to determine each second mark. The relative position relationship between M2 and the reference structure 202. That is to say, the positions of each first mark and each second mark are known, and by measuring the relative positional relationship between each first mark and each second mark, The first angle between the lens group and the reference structure can be derived. By controlling the adjustment structure to drive the bearing plate to rotate, the first angle between the lens group and the reference structure can be adjusted so that the first angle between the lens group and the reference structure is less than a preset first threshold.

Figure 7 is a schematic diagram of the distribution of the first marks and the second marks. As shown in Figure 7, the first marks M1 on the lens group 102 can be arranged in a row, and the second marks M2 on the carrier plate 201 can be arranged. In one row, the arrangement directions of the first marks M1 and the second marks M2 may be consistent. During the calibration process, in order to determine the relative positional relationship between each first mark M1 and each second mark M2, an image collector can be used to obtain the image of each first mark M1 and each second mark M2 respectively, and the first The markers M1 and the second markers M2 are arranged in the same arrangement, which makes it easier for the image collector to sequentially acquire the images of the first markers M1 and the images of the second markers M2.

In specific implementation, the first marks M1 on the lens group 102 can be arranged at equal intervals, and the second marks M2 on the carrier plate 201 can be arranged at equal intervals. This facilitates calculation of the relative positional relationship between each first mark M1 and each second mark M2, reduces the amount of calculation, and increases the calculation speed. Alternatively, the distance between two adjacent first marks M1 may be consistent with the distance between two adjacent second marks M2. Of course, during specific implementation, the first marks M1 on the lens group 102 can also be arranged in other ways, and the second marks M2 on the carrier plate 201 can also be arranged in other ways, which are not limited here.

In a possible implementation, the shape of the first mark M1 and the second mark M2 may be a "cross" shape. During specific implementation, the first mark M1 and the second mark M2 may also be set in other shapes. The shapes and sizes of the first mark M1 and the second mark M2 may be set to be consistent or inconsistent, and are not limited here.

In a possible implementation, as shown in Figure 3, the adjustment structure 203 may include: a turntable 203a fixedly connected to the bearing tray 201, and a screw 203b located on the side of the turntable 203a for driving the turntable 203a to rotate. During specific implementation, saw teeth can be provided on the side of the turntable 203a, and threads matching the saw teeth can be provided on the screw 203b. The saw teeth on the turntable 203a can engage with the threads on the screw 203b, so that the screw 203b can be rotated to drive the The turntable 203a rotates. Since the turntable 203a is fixedly connected to the bearing plate 201, during the rotation process, the turntable 203a can drive the bearing plate 201 to rotate, so that the first angle between the lens group and the reference structure can be adjusted. The pitch between the threads of the screw 203b and the radius of the turntable 203a can be determined according to the adjustment accuracy of the first angle.

Figure 8 is another structural diagram of the calibration tool in the embodiment of the present application. As shown in Figure 8, in another possible implementation, the adjustment structure 203 may include: a first top screw 203c and a second top screw 203d. . During specific implementation, the first top screw 203c and/or the second top screw 203d can be rotated to drive the bearing plate 201 to rotate, so that the first angle between the lens group and the reference structure can be adjusted.

Figure 9 is a schematic diagram of the calibration process of the position sensor in the embodiment of the present application. As shown in Figure 9, the position sensor may include: a first position sensor 103a and a second position sensor 103b. The first position sensor 103a is used to obtain the position of the reference structure 202. position in the first direction x, the second position sensor 103b is used to obtain the position of the reference structure 202 in the second direction y, the first direction x and the second direction y are both parallel to the surface of the carrier plate, and the first direction x and the second direction y The two directions y cross each other. For example, the first direction x and the second direction y may be perpendicular to each other. During specific implementation, the signal emission directions of the first position sensor 103a and the second position sensor 103b can be adjusted according to the obtained positions of the reference structure 202 in the first direction x and the second direction y.

Figure 10 is a schematic diagram of the calibration process of the displacement stage in the embodiment of the present application. As shown in Figure 10, after the calibration tool is removed and the displacement stage 104 is installed, the position sensor can also be used to calibrate the displacement stage based on the position information of the reference structure. 104 is calibrated so that the moving direction of the displacement stage 104 is substantially consistent with the signal emission direction of the position sensor. In addition, after the displacement stage 104 is calibrated, the position sensor is also used to detect the position of the displacement stage 104, so that the position of the displacement stage 104 can be adjusted through the detection data fed back by the position sensor, so that the charged particle beam emitted from the charged particle beam source can onto the wafer carried by the displacement stage 104 . By arranging two position sensors and measuring the positions of the displacement stage 104 in the first direction x and the second direction y respectively, the position coordinates of the displacement stage 104 can be determined. In specific implementation, the first position sensor 103a and the second position sensor 103b can be a laser interferometer or a laser range finder. By emitting laser light to the displacement stage 104 and receiving the laser light reflected by the displacement stage 104, it can be determined that the distance between the displacement stage 104 and The distance between the first position sensor 103a (or the second position sensor 103b) can be calculated to obtain the position coordinates of the displacement stage 104.

Based on the same technical concept, the embodiment of the present application also provides a test and calibration tool. As shown in Figure 3, the test and calibration tool 20 may include: a bearing plate 201, a reference structure 202 fixed on the bearing plate 201, and a reference structure 202 fixed on the bearing plate 201. The adjustment structure 203 is connected to the tray 201. The carrier tray 201 is provided with at least two second marks M2, and the second marks M2 are used to indicate the position information of the carrier tray 201.

With reference to Figures 2 to 4, the adjustment structure 203 is used to rotate the carrier plate 201 according to the position information of the lens group 102 and the position information of the carrier plate 201, and adjust the first angle between the lens group 102 and the reference structure 202. The first angle is The relative positional relationship between the lens group 102 and the reference structure 202 in the direction perpendicular to the carrier plate 201 is described.

In the embodiment of the present application, at least two first marks are provided on the lens group, and at least two second marks are provided on the bearing plate of the calibration tool. two marks, so that before installing the displacement stage, the calibration tool can be installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure. Realize the calibration of test and calibration tools. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

In specific implementation, the second mark may be located on the surface of the side of the carrier plate where the reference structure is provided.

In some embodiments of the present application, the reference structure may be a polygon mirror in the shape of a cuboid.

In a possible implementation, the adjustment structure may include: a turntable fixedly connected to the bearing plate, and screws located on the side of the turntable for driving the turntable to rotate. In another possible implementation, the adjustment structure may include: a first top wire and a second top wire.

In a possible implementation, the positions of the carrier plate corresponding to each second mark may be light-transmissive.

For the specific implementation of the test and calibration tool in the embodiment of the present application, reference can be made to the specific implementation of the test and calibration tool in the above-mentioned calibration system, and repeated details will not be described again.

Based on the same technical concept, the embodiment of the present application also provides a calibration method for the calibration system. Figure 11 is a schematic flow chart of the calibration method provided by the embodiment of the present application. As shown in Figure 11, the calibration method provided by the embodiment of the present application can include:

S301. Install the measurement frame, lens group and calibration tool. The calibration tool is installed on the side of the measurement frame away from the lens group. The lens group is provided with at least two first marks, and the first mark is used to indicate the lens group. position information; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks, and the second marks are used to indicate the bearing plate location information;

S302. Obtain the relative positional relationship between the lens group and the bearing plate;

S303. Determine the first angle between the lens group and the reference structure according to the relative positional relationship between the lens group and the carrier plate. The first angle is used to describe the relative positional relationship between the lens group and the reference structure in the direction perpendicular to the carrier plate;

S304. Rotate the bearing plate through the adjustment structure until the first angle is smaller than the preset first threshold.

In specific implementation, the angle adjustment value can be determined according to the first angle and the preset first threshold. According to the determined angle adjustment value, the adjustment structure is controlled to drive the bearing plate to rotate to adjust the third distance between the lens group and the reference structure. an angle until the adjusted first angle is less than the preset first threshold. The above-mentioned first threshold can be set according to the stroke capability of the displacement stage. For example, the above-mentioned first threshold can be set to 500 urad.

In the calibration method provided by the embodiment of the present application, at least two first marks are set on the lens group and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement can be The calibration tool is installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Subsequently, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

As shown in FIG. 2 , in the above step S301 , the lens group 102 can be installed above the measurement frame 101 , and the calibration tool 20 can be installed on the side of the measurement frame 101 away from the lens group 102 . With reference to FIG. 2 and FIG. 3 , the calibration tool 20 may include: a bracket 21 and a plurality of pillars 22 located on the bracket 21 . The bearing plate 201 , the reference structure 202 and the adjustment structure 203 can be disposed on the bracket 21 . The measurement and calibration tool 20 can be fixedly connected to the measurement frame 101 through the support 22 .

In specific implementation, in the above step S302, obtaining the relative positional relationship between the lens group and the carrier plate may include:

Figure 12 is a schematic diagram of the image collection process in this embodiment of the present application. As shown in Figure 12, the image collector may include: a first image collector 402 and a second image collector 403. In a possible embodiment, the above-mentioned acquisition of at least one image through an image collector may include:

A linear guide rail 401 is provided between the lens group 102 and the calibration tool 20. In specific implementation, the extension direction of the linear guide rail 401 can be consistent with the direction of the first direction x;

The first image collector 402 and the second image collector 403 are installed on the linear guide rail 401. The first image collector 402 and the second image collector 403 can slide along the linear guide rail 401, and the first image collector 402 and the second image collector 403 can slide along the linear guide rail 401. The relative positions of the two image collectors 403 remain unchanged. The collection surface of the first image collector 402 faces the lens group 102 , and the collection surface of the second image collector 403 faces the calibration tool 20 . That is to say, two image collectors are used to collect images of the first mark M1 and the second mark M2 respectively, wherein the first image collector 402 is used to collect the image of the first mark M1, and the second image collector 403 is used to collect the image of the first mark M1. Collect the image of the second marker M2;

The first image collector 402 and the second image collector 403 are controlled to move along the linear track 401 at the same time, so that the first image collector 402 sequentially collects at least two images of each first mark M1, and the second image collector 403 sequentially collects At least two images of each second mark M2. In FIG. 12 , T1 represents the image of the first mark M1 collected by the first image collector 402 , and T2 represents the image of the second mark M2 collected by the second image collector 403 . During specific implementation, the first image collector 402 and the second image collector 403 can move synchronously, that is, the relative positions of the first image collector 402 and the second image collector 403 remain unchanged. At least one image of the first mark M1 is acquired each time, and the second image collector 403 acquires at least one image of the second mark M2 each time. In the embodiment of the present application, two image collectors are used to collect images of the first mark M1 and the second mark M2 respectively, and the collection speed is relatively fast.

Afterwards, the linear guide rail 401, the first image collector 402 and the second image collector 403 are removed.

Figure 13 is another schematic diagram of the image acquisition process in the embodiment of the present application. As shown in Figure 13, in another possible embodiment, the position of the carrier plate 201 corresponding to each second mark M2 can be set to be light-transmissive. That is, the carrier tray 201 has a light-transmitting area Q at the position of the second mark M2. The carrier tray 201 can be made of transparent material, such as crystallized glass material, or it can be at the position of the carrier tray 201 corresponding to the second mark M2. Hollow arrangement, in this way, the image collector (ie, the third image collector 404) can be provided only on the side of the calibration tool 20 away from the lens group 102, and the third image collector 404 can pass through the light-transmitting area of the carrier plate 201 Q acquires images of the first mark M1 and the second mark M2.

A linear guide rail 401 is provided on the side of the calibration tool 20 away from the lens group 102. In specific implementation, the extension direction of the linear guide rail 401 can be consistent with the direction of the first direction x;

The third image collector 404 is installed on the linear guide rail 401, and the third image collector 404 can slide along the linear guide rail 401; the collection surface of the third image collector 404 faces the calibration tool 20;

The third image collector 404 is controlled to move along the linear guide 401 and acquire at least one image including at least one first mark and at least one second mark. That is to say, in the embodiment shown in FIG. 13 , only one image collector can be used to collect the images of the first mark M1 and the second mark M2 simultaneously. In FIG. 13 , T3 represents the third image collected by the third image collector 404 . An image of a mark M1 and a second mark M2. During the acquisition process of the third image collector 404, the height of the calibration tool 20 can be adjusted so that the first mark M1 and the second mark M2 are within the depth of field of the third image collector 404.

After that, the linear guide 401 and the third image collector 404 are removed.

Referring to Figures 12 and 13, in order to facilitate the image collector to collect images of the first marks M1 and the second marks M2, the first marks M1 on the lens group 102 can be arranged in a row, and the second marks M1 on the carrier plate 201 can be arranged in a row. The markers M2 are arranged in a row, and the first markers M1 and the second markers M2 are arranged in the same direction. In this way, the first markers M1 and the second markers M2 can more easily fall into the collection range of the image collector.

In the above step S303, the first angle between the lens group and the reference structure can be determined based on the relative positional relationship between the lens group and the carrier plate, and the predetermined relative positional relationship between each second mark in the carrier plate and the reference structure. In the embodiment of the present application, referring to FIG. 12 , according to the relative positional relationship between each first mark M1 and each second mark M2, the relative positional relationship between the lens group 102 and the carrier tray 201 can be determined. The relative positional relationship between the lens group 102 and the carrier tray 201 can be described by a second angle. The second angle is used to describe the relative positional relationship between the lens group 102 and the carrier tray 201 in a direction perpendicular to the carrier tray 201 . The second angle can be determined as follows:

Any two first marks M1 and the corresponding two second marks M2 are regarded as a mark group. For example, the two first marks M1 and the two second marks M2 in Figure 12 can be regarded as a mark group;

In each mark group, the angle Δθ between the line connecting the two first marks M1 and the line connecting the two second marks M2 can be determined according to the following formula:

Among them, L ₁ represents the distance between the two first marks M1 in the mark group in the first direction x, Δy ₁ represents the distance difference between the two first marks M1 in the mark group and the linear track 401 in the second direction y, L ₂ represents the distance between the two second marks M2 in the mark group in the first direction x, Δy ₂ represents the distance difference in the second direction y between the two second marks M2 in the mark group and the linear track 401; first The direction x and the second direction y are both parallel to the surface of the measurement frame, and the first direction x and the second direction y cross each other. For example, the first direction x and the second direction y can be perpendicular to each other;

The average value of the angles Δθ of each mark group is used as the second angle between the lens group 102 and the carrier plate 201 .

During the processing of the lens group 102, laser etching or other means may be used to form at least two first marks M1 on the lens group 102. Afterwards, the position of each first mark M1 can be measured and calibrated through an optical microscope or an electron microscope. That is, the position of each first mark M1 on the lens group 102 is known, and the position of the first mark M1 can represent the position of the lens group 102 . Moreover, during the processing of the calibration tool 20, at least two second marks M2 can be formed on the bearing plate 201, and the position of each second mark M2 can be calibrated through optical detection or other means to determine the relationship between each second mark M2 and The relative position relationship of the reference structure 202. That is to say, the positions of each first mark and each second mark are known. In this way, according to the positions of each first mark and each second mark and the above formula, the third distance between the lens group 102 and the carrier plate 201 can be obtained. From the two angles, the first angle between the lens group 102 and the reference structure 202 can be derived. Therefore, the angle adjustment value can be determined based on the determined first angle between the lens group and the reference structure and the preset first threshold. Then, the adjustment structure can be controlled to drive the bearing plate to rotate, and the relationship between the lens group and the reference structure can be adjusted. The first angle between the lens group and the reference structure finally makes the first angle between the lens group and the reference structure smaller than the preset first threshold.

In specific implementation, the first marks M1 on the lens group 102 can be arranged at equal intervals, and the second marks M2 on the carrier plate 201 can be arranged at equal intervals. The distance between two adjacent first marks M1 can be the same as that between two adjacent first marks M1. The spacing between the two second marks M2 is consistent. In this way, the above formula can be simplified to the following formula:

Therefore, it is easy to calculate the angle Δθ between each first mark M1 and each second mark M2, reducing the calculation amount and increasing the calculation speed.

Referring to Figure 3, in a possible implementation, the adjustment structure 203 may include: a turntable 203a fixedly connected to the bearing tray 201, and a screw 203b located on the side of the turntable 203a for driving the turntable 203a to rotate.

In the above step S304, rotating the bearing plate through the adjustment structure may include:

By rotating the screw 203b, the turntable 203a is driven to rotate, so as to drive the bearing plate 201 to rotate.

During specific implementation, saw teeth can be provided on the side of the turntable 203a, and threads matching the saw teeth can be provided on the screw 203b. The saw teeth on the turntable 203a can engage with the threads on the screw 203b, so that the screw 203b can be rotated to drive the The turntable 203a rotates. Since the turntable 203a is fixedly connected to the bearing plate 201, during the rotation process, the turntable 203a can drive the bearing plate 201 to rotate, so that the first angle between the lens group and the reference structure can be adjusted. The pitch between the threads of the screw 203b and the radius of the turntable 203a can be determined according to the adjustment accuracy of the first angle.

Referring to FIG. 8 , in another possible implementation, the adjustment structure 203 may include: a first top wire 203c and a second top wire 203d.

By rotating the first jack screw 203c and/or the second jack screw 203d, the bearing plate 201 is driven to rotate.

As shown in Figure 9, the reference structure 202 can be a polygonal mirror in the shape of a cuboid. That is to say, any two adjacent sides of the reference structure 202 are perpendicular to each other, and each side of the reference structure 202 is a reflective surface. In this way, the reference structure 202 can be used as an orientation reference in the Cartesian coordinate system. The reference structure 202 may include: adjacent first reflective surface 202a and second reflective surface 202b. The position sensor may include: a first position sensor 103a and a second position sensor 103b. After the displacement stage 104 is installed, the first position sensor 103a is used to detect the position of the displacement stage 104 in the first direction x, and the second position sensor 103b is used to detect the position of the displacement stage 104 in the first direction x. The position of the displacement stage 104 in the second direction y is detected.

Combined with Figure 2 and Figure 9, the above calibration method can also include:

The first position sensor 103a and the second position sensor 103b are installed on the measurement frame 101. In specific implementation, the first position sensor 103a and the second position sensor 103b can be installed on the side of the measurement frame 101 away from the lens group 102;

Adjust the first position sensor 103a so that the signal emission direction of the first position sensor 103a is perpendicular to the first reflective surface 202a of the reference structure 202;

The second position sensor 103b is adjusted so that the signal emission direction of the second position sensor 103b is perpendicular to the second reflective surface 202b of the reference structure 202.

In the embodiment of the present application, since the reference structure 202 can be used as an orientation reference in the Cartesian coordinate system, the first position sensor 103a and the second position sensor 103b can be adjusted according to the orientation of the reflective surface of the reference structure 202 so that the first position sensor The signal emission direction of the second position sensor 103a is perpendicular to the first reflective surface 202a, so that the signal emission direction of the second position sensor 103b is perpendicular to the second reflective surface 202b. In practical applications, the direction perpendicular to the first reflective surface 202a can be regarded as the first direction x, and the direction perpendicular to the second reflective surface 202b can be regarded as the second direction y. In this way, after the displacement stage 104 is installed, the third direction can be A position sensor 103a detects the position of the displacement stage in the first direction x, and the second position sensor 103b can detect the position of the displacement stage in the second direction y, so that the position of the displacement stage can be accurately positioned.

In specific implementation, the first position sensor 103a and the second position sensor 103b may be laser interferometers or laser rangefinders. Can By controlling the first position sensor 103a to emit laser light toward the reference structure 202 along the first direction x and receiving the reflected light from the reflective surface of the reference structure 202, the spot overlap intensity of the emitted light and the reflected light in the first direction x is read. When the light spot overlap intensity reaches the maximum value, the signal emission direction of the first position sensor 103a is approximately perpendicular to the first reflective surface 202a. Similarly, by controlling the second position sensor 103b to emit laser light toward the reference structure 202 along the second direction y, and receiving the reflected light from the reflective surface of the reference structure 202, the overlap of the light spots of the emitted light and the reflected light in the second direction y can be read. intensity, when the light spot overlap intensity reaches the maximum value, the signal emission direction of the second position sensor 103b is approximately perpendicular to the second reflective surface 202b.

After the position sensor is installed and calibrated, the calibration method provided by the embodiment of the present application may also include:

Remove the calibration tools;

Referring to Figures 4 and 10, the displacement stage 104 is installed on the side of the measurement frame 101 away from the lens group 102, and the displacement stage 104 is adjusted so that the displacement stage 104 can move along the first direction x and the second direction y. The first direction x is consistent with the signal emission direction of the first position sensor 103a, and the second direction y is consistent with the signal emission direction of the second position sensor 103b.

In the calibration method provided by the embodiment of the present application, the lens group can be aligned with the reference structure by setting up a calibration tool. After that, the reflective surface of the reference structure can be used to adjust the signal emission direction of the position sensor. Subsequently, the signal output of the position sensor can be adjusted according to the signal of the position sensor. By adjusting the displacement stage in the emission direction, the moving direction of the displacement stage can be basically consistent with the direction of the signal emission direction of the position sensor, thereby improving the etching accuracy of the semiconductor etching equipment or the detection accuracy of the semiconductor detection equipment. Moreover, in the calibration method provided by the embodiment of the present application, there is no need to adjust the connection relationship between the lens group and the measurement frame, which can effectively improve the connection stiffness of the lens group and the measurement frame and reduce the dynamic error of the system. There is no need to use a micro-moving stage and other structures in the lens group, and the lens group and the displacement stage can be quickly and accurately compared. The calibration method is highly flexible.

Based on the same technical concept, the embodiment of the present application also provides a calibration method of the calibration system. Figure 14 is another schematic flow chart of the calibration method provided by the embodiment of the present application. As shown in Figure 14, the calibration method provided by the embodiment of the present application Methods can include:

S401. Install the measurement frame and the calibration tool according to the lens group. The calibration tool is installed on the side of the measurement frame away from the lens group. The lens group is provided with at least two first marks, and the first marks are used to indicate the lens group. position information; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks, and the second marks are used to indicate the bearing plate location information;

S402. Obtain the relative positional relationship between the lens group and the bearing plate;

S403. Determine the first angle between the lens group and the reference structure according to the relative positional relationship between the lens group and the carrier plate. The first angle is used to describe the relative positional relationship between the lens group and the reference structure in the direction perpendicular to the carrier plate;

S404. Adjust the first angle by rotating the bearing plate through the adjustment structure;

S405. When the first angle is less than the preset first threshold, obtain the position information of the reference structure and remove the calibration tool;

S406. Install and adjust the displacement stage according to the position information of the reference structure.

In the calibration method provided by the embodiment of the present application, at least two first marks are set on the lens group and at least two second marks are set on the bearing plate of the measurement and calibration tool. In this way, before installing the displacement stage, the measurement can be The calibration tool is installed on the side of the measurement frame away from the lens group, and the adjustment structure drives the bearing plate to rotate to adjust the first angle between the lens group and the reference structure to achieve calibration of the measurement and calibration tool. Then, the position of the displacement stage can be calibrated based on the position information of the reference structure to achieve alignment between the lens group and the displacement stage.

In the embodiment of the present application, the specific implementation manner of the above-mentioned step S401 is consistent with the specific implementation manner of the above-mentioned step S301, the specific implementation manner of the above-mentioned step S402 is consistent with the specific implementation manner of the above-mentioned step S302, and the specific implementation manner of the above-mentioned step S403 is the same as the above-mentioned specific implementation manner. The specific implementation manner of step S303 is consistent with that of step S404. The specific implementation manner of step S304 is consistent with that of step S304. The overlapping parts will not be described again.

Referring to Figure 9, the reference structure 202 can be a polygonal mirror in the shape of a cuboid. That is to say, any two adjacent sides of the reference structure 202 are perpendicular to each other, and each side of the reference structure 202 is a reflective surface. In this way, The reference structure 202 can be used as an orientation reference in the Cartesian coordinate system. The reference structure 202 may include: adjacent first reflective surface 202a and second reflective surface 202b.

In the above step S405, when the first angle is less than the preset first threshold, obtaining the position information of the reference structure may specifically include:

Install the first position sensor 103a and the second position sensor 103b on the side of the measurement frame 101 away from the lens group 102;

In specific implementation, the first position sensor 103a and the second position sensor 103b may be laser interferometers or laser rangefinders. By controlling the first position sensor 103a to emit laser light toward the reference structure 202 along the first direction x and receiving the reflected light from the reflective surface of the reference structure 202, the spot overlap intensity of the emitted light and the reflected light in the first direction When the light spot overlap intensity reaches the maximum value, the signal emission direction of the first position sensor 103a is approximately perpendicular to the first reflective surface 202a. Similarly, by controlling the second position sensor 103b to emit laser light toward the reference structure 202 along the second direction y, and receiving the reflected light from the reflective surface of the reference structure 202, the overlap of the light spots of the emitted light and the reflected light in the second direction y can be read. intensity, when the light spot overlap intensity reaches the maximum value, the signal emission direction of the second position sensor 103b is approximately perpendicular to the second reflective surface 202b.

After installing and calibrating the position sensor, remove the calibration tool.

In the above step S406, installing and adjusting the displacement stage according to the position information of the reference structure may specifically include:

Although the preferred embodiments of the present application have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once the basic inventive concepts are apparent. Therefore, it is intended that the appended claims be construed to include the preferred embodiments and all changes and modifications that fall within the scope of this application.

Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. In this way, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of this application and equivalent technologies, then this application is also intended to include these modifications and variations.

Claims

A calibration system, characterized by including: a measurement frame, a measurement and calibration tool and a displacement stage;

The calibration system is used to calibrate the relative positions of the lens group, the calibration tool, and the displacement stage;

The measurement frame is connected to the lens group, and the measurement frame is also equipped with the calibration tool. The lens group is located on the side of the measurement frame away from the calibration tool; the lens group is provided with at least Two first marks, the first marks are used to indicate the position information of the lens group;

The calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks, and the second The mark is used to indicate the position information of the carrier disk;

Wherein, the adjustment structure is used to rotate the carrier plate according to the position information of the lens group and the position information of the carrier plate, and adjust the first angle between the lens group and the reference structure, and the second An angle is used to describe the relative positional relationship between the lens group and the reference structure in a direction perpendicular to the carrier plate.
The calibration system of claim 1, further comprising: a position sensor;

The position sensor is used to obtain position information of the reference structure when the first angle is less than a first threshold;

Wherein, the position information is used to calibrate the displacement stage when the displacement stage is installed after the calibration tool is removed.
The calibration system of claim 2, wherein the position sensor includes: a first position sensor and a second position sensor;

The first position sensor is used to obtain the position of the reference structure in the first direction;

The second position sensor is used to obtain the position of the reference structure in the second direction;

The first direction and the second direction are both parallel to the surface of the bearing plate, and the first direction and the second direction intersect each other.
The calibration system according to any one of claims 1 to 3, wherein the first mark is located on the surface of the lens group facing the measurement frame, and the second mark is located on the bearing plate. There is a surface on one side of the reference structure.
The calibration system according to any one of claims 1 to 4, wherein the at least two first marks are arranged in a row, the at least two second marks are arranged in a row; and the at least two second marks are arranged in a row; The first marks are arranged at equal intervals, and the at least two second marks are arranged at equal intervals.
The calibration system according to any one of claims 1 to 5, further comprising: an image collector;

The image collector is used to acquire at least one image, the image containing at least one of the at least two first markers and/or at least one of the at least two second markers;

Wherein, the at least one image and the corresponding position information of the image collector are used to determine the relative positional relationship between the lens group and the carrier plate.
The calibration system of claim 6, wherein the positions of the carrier plate corresponding to the at least two second marks are light-transmissive.
The calibration system according to claim 7, characterized in that:

The image collector is installed below the bearing plate and on the side away from the lens group;

The image collector is used to acquire at least one image through the light-transmitting position on the carrier plate, the image including at least one of the at least two second marks and the at least two first marks. at least one of them.
The calibration system according to any one of claims 1 to 8, wherein the adjustment structure includes: a turntable fixedly connected to the bearing tray, and screws located on the side of the turntable for driving the turntable to rotate. .
The calibration system according to any one of claims 1 to 9, wherein the reference structure is a polygonal mirror in the shape of a cuboid.
A test and calibration tool, characterized in that it includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing plate is provided with at least two second marks , the second mark is used to indicate the position information of the carrier disk;

Wherein, the adjustment structure is used to rotate the carrier plate according to the position information of the lens group and the position information of the carrier plate, and adjust the first angle between the lens group and the reference structure, and the second An angle is used to describe the relative positional relationship between the lens group and the reference structure in a direction perpendicular to the carrier plate.
The calibration tool according to claim 11, wherein the second mark is located on a surface of the bearing plate on the side where the reference structure is provided.
The calibration tool according to claim 11 or 12, wherein the reference structure is a polygonal mirror in the shape of a cuboid.
The testing and calibration tool according to any one of claims 11 to 13, characterized in that the adjustment structure includes: a turntable fixedly connected to the bearing tray, and a side member located on the side of the turntable for driving the turntable to rotate. screw.
The calibration tool according to any one of claims 11 to 14, wherein the positions of the carrier plate corresponding to the at least two second marks are light-transmissive.
A calibration method for a calibration system, characterized by including:

Install the measurement frame, the lens group and the calibration tool, wherein the calibration tool is installed on the side of the measurement frame away from the lens group; wherein the lens group is provided with at least two first marks, the The first mark is used to indicate the position information of the lens group; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing The disk is provided with at least two second marks, the second marks being used to indicate position information of the carrier disk;

Obtain the relative positional relationship between the lens group and the carrier plate;

According to the relative positional relationship between the lens group and the bearing plate, a first angle between the lens group and the reference structure is determined. The first angle is used to describe the relationship between the lens group and the reference structure. The relative positional relationship in the direction perpendicular to the bearing plate;

The bearing plate is rotated through the adjustment structure until the first angle is smaller than a preset first threshold.
The calibration method according to claim 16, wherein the obtaining the relative positional relationship between the lens group and the carrier plate includes:

Acquire at least one image by an image collector, the image containing at least one of the at least two first markers and/or at least one of the at least two second markers;

The relative positional relationship between the lens group and the carrier plate is determined based on the at least one image and the corresponding position information of the image collector.
The calibration method according to claim 17, wherein the image collector includes a first image collector and a second image collector, and obtaining at least one image through the image collector specifically includes:

A linear guide rail is provided between the lens group and the calibration tool;

The first image collector and the second image collector are installed on the linear guide rail, the first image collector and the second image collector can slide along the linear guide rail, and the The relative position of the first image collector and the second image collector remains unchanged; the collection surface of the first image collector faces the lens group, and the collection surface of the second image collector faces the measurement surface. calibration tools;

The first image collector and the second image collector are controlled to move along the linear track at the same time, so that the first image collector sequentially collects at least two images of the at least two first marks, so The second image collector collects at least two images of the at least two second markers in sequence.
The calibration method according to claim 17, wherein the image collector includes a third image collector, and the position of the carrier plate corresponding to the second mark is light-transmissive;

The acquisition of at least one image through the image collector specifically includes:

A linear guide rail is provided on the side of the calibration tool away from the lens group;

Install a third image collector on the linear guide rail, and the third image collector can slide along the linear guide rail, and the collection surface of the image collector faces the calibration tool;

Control the third image collector to move along the linear guide rail and acquire at least one image, the image including at least one of the at least two first marks and at least one of the at least two second marks. one.
The calibration method according to any one of claims 16 to 19, wherein the adjustment structure includes: a turntable fixedly connected to the bearing tray, and screws located on the side of the turntable for driving the turntable to rotate. ;

The rotation of the bearing plate through the adjustment structure specifically includes:

By rotating the screw, the turntable is driven to rotate, thereby driving the bearing plate to rotate.
The calibration method according to any one of claims 16 to 20, wherein the reference structure is a polygon mirror in the shape of a cuboid; the reference structure includes: adjacent first reflective surfaces and second reflective surfaces;

The calibration method also includes:

Install the first position sensor and the second position sensor on the measurement frame;

Adjust the first position sensor so that the signal emission direction of the first position sensor is perpendicular to the first reflective surface;

The second position sensor is adjusted so that the signal emission direction of the second position sensor is perpendicular to the second reflective surface.
A calibration method for a calibration system, characterized by including:

The measurement frame and the calibration tool are installed according to the lens group, wherein the calibration tool is installed on the side of the measurement frame away from the lens group; wherein the lens group is provided with at least two first marks, and the The first mark is used to indicate the position information of the lens group; the calibration tool includes: a bearing plate, a reference structure fixed on the bearing plate, and an adjustment structure connected to the bearing plate; the bearing The disk is provided with at least two second marks, the second marks being used to indicate position information of the carrier disk;

Obtain the relative positional relationship between the lens group and the carrier plate;

According to the relative positional relationship between the lens group and the bearing plate, a first angle between the lens group and the reference structure is determined. The first angle is used to describe the relationship between the lens group and the reference structure. The relative positional relationship in the direction perpendicular to the bearing plate;

Adjust the first angle by rotating the bearing plate through the adjustment structure;

When the first angle is less than the preset first threshold, obtain the position information of the reference structure and remove the calibration tool;

The translation stage is mounted and adjusted based on the position information of the reference structure.
The calibration method according to claim 22, wherein the obtaining the relative positional relationship between the lens group and the carrier plate includes:

Acquire at least one image by an image collector, the image containing at least one of the at least two first markers and/or at least one of the at least two second markers;

The relative positional relationship between the lens group and the carrier plate is determined based on the at least one image and the corresponding position information of the image collector.
The calibration method according to claim 23, wherein the image collector includes a first image collector and a second image collector, and obtaining at least one image through the image collector specifically includes:

A linear guide rail is provided between the lens group and the calibration tool;

The first image collector and the second image collector are installed on the linear guide rail, the first image collector and the second image collector can slide along the linear guide rail, and the The relative position of the first image collector and the second image collector remains unchanged; the collection surface of the first image collector faces the lens group, and the collection surface of the second image collector faces the measurement surface. calibration tools;

The first image collector and the second image collector are controlled to move along the linear track at the same time, so that the first image collector sequentially collects at least two images of the at least two first marks, so The second image collector collects at least two images of the at least two second markers in sequence.
The calibration method according to claim 23, wherein the image collector includes a third image collector, and the position of the carrier plate corresponding to the second mark is light-transmissive;

The acquisition of at least one image through the image collector specifically includes:

A linear guide rail is provided on the side of the calibration tool away from the lens group;

Install a third image collector on the linear guide rail, and the third image collector can slide along the linear guide rail, and the collection surface of the image collector faces the calibration tool;

Control the third image collector to move along the linear guide rail and acquire at least one image, the image including at least one of the at least two first marks and at least one of the at least two second marks. one.
The calibration method according to any one of claims 22 to 25, wherein the adjustment structure includes: a turntable fixedly connected to the bearing tray, and screws located on the side of the turntable for driving the turntable to rotate. ;

The rotation of the bearing plate through the adjustment structure specifically includes:

By rotating the screw, the turntable is driven to rotate, thereby driving the bearing plate to rotate.
The calibration method according to any one of claims 22 to 26, wherein the reference structure is a polygon mirror in the shape of a cuboid; the reference structure includes: adjacent first reflective surfaces and second reflective surfaces;

The calibration method also includes:

Install the first position sensor and the second position sensor on the measurement frame;

Adjust the first position sensor so that the signal emission direction of the first position sensor is perpendicular to the first reflective surface;

The second position sensor is adjusted so that the signal emission direction of the second position sensor is perpendicular to the second reflective surface.