A pre-check system and a pre-check method of an electron gun

Abstract

The application discloses a pre-check system and a pre-check method of an electron gun. The pre-check system comprises a deflection lens barrel, a measuring lens barrel and a control module. The measuring lens barrel is located directly below the deflection lens barrel, and both are electrically connected with the control module. During pre-check, the electron gun lens barrel to be detected is installed directly above the deflection lens barrel, and the control module is electrically connected with the electron gun lens barrel. The control module is used for controlling the electron gun to emit an electron beam, and is used for controlling the electron beam to deflect in a first direction and a second direction through the deflection lens barrel, so that the electron beam performs point-by-point scanning on a first scanning range. An electron beam collecting device in the measuring lens barrel is used for collecting a current value corresponding to each scanning point. The control module is further used for generating a gray-scale image based on the current value, and adjusting the position of the electron gun according to the position of a bright spot in the gray-scale image until the center of the bright spot coincides with the center of the image. The application can improve the maintenance efficiency of the electron microscope equipment, reduce the maintenance difficulty and reduce the downtime.

Description

Technical Field

[0001] The present invention relates to the field of scanning electron microscope maintenance, and in particular to a pre-inspection system and a pre-inspection method for an electron gun. Background Art

[0002] Electron beam scanning measuring instruments are core measurement equipment in the semiconductor manufacturing industry. They use a high-voltage power supply to control the electron gun to emit a high-energy electron beam. Deflection coils and convergence coils are then used to control the electron beam to bombard the sample surface. The excited secondary electrons are detected to obtain image information of the sample surface, allowing for high-precision measurement of critical dimensions of the sample based on clear surface image information. The cathode filament of the electron gun wears out during operation and needs to be replaced regularly. Due to errors in machining and assembly, replacing the electron gun filament can cause the center of the electron beam (emission axis) to deviate from the central axis (optical axis) of each aperture, increasing astigmatism and reducing the image resolution and signal-to-noise ratio. In severe cases, the electron beam cannot pass through the aperture to reach the sample, making it impossible for the electron microscope to form an image. Therefore, after replacing the cathode filament of the electron gun, it is necessary to adjust the alignment of the electron beam emitted by the cathode filament with the central axis of the electron optical system. This is referred to as alignment or coaxialization.

[0003] Currently, electron gun cathode filament replacement often involves on-site replacement, requiring the old filament to be removed on-site. During this process, the vacuum chamber must be broken, and after installing the new filament, a high vacuum must be established and the electron gun emission axis aligned. However, to ensure the normal and stable operation of the electron microscope's electron optical system, an ultra-high vacuum level is required within the electron gun and lens barrel. Establishing this ultra-high vacuum level is complex and time-consuming. Furthermore, the measurement principle of the scanning electron microscope (with magnifications exceeding thousands) makes it difficult to locate the alignment spot, making on-site alignment extremely difficult. Furthermore, the filament's high precision and cleanliness requirements make it extremely susceptible to damage and contamination during processing, transportation, and installation. If a defective filament is discovered after on-site replacement, the replacement process must be repeated, consuming a significant amount of time and manpower. Summary of the Invention

[0004] The present invention provides an electron gun pre-inspection system and a pre-inspection method, so as to improve the maintenance efficiency of electron microscope equipment, reduce the maintenance difficulty and shorten the downtime.

[0005] In a first aspect, an embodiment of the present invention provides a pre-inspection system for an electron gun, comprising: a deflection lens barrel, a measurement lens barrel, and a control module;

[0006] The measuring lens barrel is located directly below the deflecting lens barrel, and the deflecting lens barrel and the measuring lens barrel are electrically connected to the control module respectively; the measuring lens barrel includes an aperture and an electron beam collecting device, the center of the aperture has a light-transmitting hole, and the electron beam collecting device is located directly below the aperture;

[0007] During pre-inspection, the electron gun lens barrel to be inspected is installed directly above the deflection lens barrel, and the control module is electrically connected to the electron gun lens barrel; the electron gun lens barrel includes an electron gun;

[0008] The control module is used to control the electron gun to emit an electron beam, and to control the deflection of the electron beam in a first direction and a second direction through a deflection lens barrel, so that the electron beam scans a first scanning range point by point; the first direction and the second direction are orthogonal to each other and are both parallel to the plane where the aperture is located; the position of the electron gun is simultaneously the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction;

[0009] The electron beam collecting device is used to collect the current value corresponding to each scanning point of the electron beam during the scanning process and send the current value to the control module;

[0010] The control module is also used to generate a grayscale image based on the current value, and adjust the position of the electron gun according to the position of the bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical axis; the bright spot corresponds to the imaging area of ​​the light-transmitting hole.

[0011] Optionally, the deflection lens barrel includes a first deflection coil and a second deflection coil; the control module is used to control the deflection range of the electron beam in the first direction by controlling the current of the first deflection coil; the control module is also used to control the deflection range of the electron beam in the second direction by controlling the current of the second deflection coil.

[0012] Optionally, the control module includes a controller, a drive control circuit, a deflection control circuit, and a measurement circuit;

[0013] The driving control circuit is connected between the electron gun barrel and the controller;

[0014] The deflection control circuit is connected between the deflection lens barrel and the controller;

[0015] The measuring circuit is connected between the measuring lens barrel and the controller.

[0016] Optionally, the pre-inspection system further includes a human-computer interaction module, and the human-computer interaction module is electrically connected to the controller.

[0017] In a second aspect, an embodiment of the present invention provides a pre-inspection method for an electron gun, which is performed using a pre-inspection system provided by any embodiment of the present invention. The pre-inspection method includes:

[0018] Control the electron gun to emit electron beam;

[0019] The electron beam is deflected in a first direction and a second direction by a deflection lens barrel so that the electron beam scans a first scanning range point by point; the first direction and the second direction are orthogonal to each other and are both parallel to the plane where the aperture is located; and the position of the electron gun is simultaneously the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction;

[0020] The current value corresponding to each scanning point of the electron beam collected by the electron beam collecting device during the scanning process is received, and a grayscale image is generated based on the current value. The position of the electron gun is adjusted according to the position of the bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical axis; the bright spot corresponds to the imaging area of ​​the light-transmitting hole.

[0021] Optionally, the deflection lens barrel includes a first deflection coil and a second deflection coil; controlling the electron beam to deflect in the first direction and the second direction by the deflection lens barrel so that the electron beam scans the first scanning range point by point includes:

[0022] determining a first scanning step number of the first deflection coil and a second scanning step number of the second deflection coil according to a preset pixel value of the grayscale image;

[0023] calculating a first maximum current of the first deflection coil and a second maximum current of the second deflection coil according to a preset magnification value of the grayscale image;

[0024] Determine a first current range according to the first maximum current; wherein the first maximum current is XI1, the first current range is -XI1 to +XI1; XI1 is a positive number;

[0025] Determine a second current range according to the second maximum current; wherein the second maximum current is YI1, the second current range is -YI1 to +YI1; YI1 is a positive number;

[0026] Calculating a first deflection current of the first deflection coil corresponding to each scanning point in the first direction according to the first current range and the first scanning step number;

[0027] Calculating a second deflection current of the second deflection coil corresponding to each scanning point in the second direction according to the second current range and the second number of scanning steps;

[0028] The current change of the first deflection coil is controlled according to the first deflection current corresponding to each scanning point, and the current change of the second deflection coil is controlled according to the second deflection current corresponding to each scanning point, so that the electron beam scans point by point within the first scanning range.

[0029] Optionally, in the grayscale image, the number of pixels in each row is equal to the number of pixels in each column.

[0030] Optionally, during the pre-check process, the preset magnification value is variable, and different grayscale images are obtained based on different preset magnification values.

[0031] Optionally, adjusting the position of the electron gun according to the position of the bright spot in the grayscale image includes:

[0032] Setting the preset magnification value to a first magnification to obtain a first grayscale image;

[0033] determining whether a bright spot exists in the first grayscale image; if not, adjusting the position of the electron gun, and again determining whether a bright spot exists in the updated first grayscale image; if so, adjusting the position of the electron gun so that the center of the bright spot moves toward the center of the image;

[0034] The preset magnification value is set to the second magnification to obtain a second grayscale image, and the position of the electron gun is adjusted until the center of the bright spot coincides with the center of the image;

[0035] The first magnification is smaller than the second magnification.

[0036] Optionally, the pre-check method further includes:

[0037] When the preset magnification value is the first magnification, if there is still no bright spot in the updated first grayscale image, it is determined that the electron gun is faulty; and / or,

[0038] After the center of the bright spot coincides with the center of the image, the first current value of the electron beam passing through the light-transmitting hole collected by the electron beam collecting device is received. If the difference between the first current value and the standard current value is greater than a preset threshold, it is determined that the electron gun is faulty.

[0039] The pre-inspection system and pre-inspection method provided in the embodiments of the present invention can complete pre-inspection work such as alignment of the emission axis of the electron gun and quality inspection. After the pre-inspection is completed, the electron gun barrel can be installed as a whole in the scanning equipment. In this way, the disadvantages of on-site replacement of the cathode filament can be avoided (for example, avoiding the problems of complex, time-consuming and difficult on-site alignment operations, avoiding the problem of a large amount of time wasted due to the installation of defective products, and avoiding the problem of damage to the cathode filament due to transportation and disassembly). In addition, since the emission axis of the electron gun has completed the preliminary alignment operation, only fine-tuning of the on-site scanning electron microscope equipment is required, which can avoid the need to search for the light spot over a large area, improve the maintenance efficiency of the electron microscope equipment, reduce the difficulty of maintenance of the electron microscope equipment, and reduce the downtime of the electron microscope equipment.

[0040] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 This is a structural diagram of a pre-inspection system for an electron gun provided by an embodiment of the present invention when performing pre-inspection work;

[0043] Figure 2 yes Figure 1 The schematic diagram of the structure of the measuring lens barrel in the pre-inspection system shown in FIG.

[0044] Figure 3 This is a schematic diagram of the structure of a typical existing electron gun barrel;

[0045] Figure 4 yes Figure 1 A schematic diagram of the top view of the deflection lens barrel in the pre-inspection system shown;

[0046] Figure 5 is a structural diagram of another pre-inspection system provided by an embodiment of the present invention;

[0047] Figure 6 This is one of the schematic diagrams of the working principle of the pre-check system provided by an embodiment of the present invention;

[0048] Figure 7 This is the second schematic diagram of the working principle of the pre-inspection system provided by an embodiment of the present invention;

[0049] Figure 8 This is the third schematic diagram of the working principle of the pre-inspection system provided by an embodiment of the present invention;

[0050] Figure 9 1 is a flow chart of a pre-inspection method for an electron gun provided by an embodiment of the present invention;

[0051] Figure 10 This is a schematic diagram of a scanning principle provided by an embodiment of the present invention;

[0052] Figure 11 is a schematic diagram of a first grayscale image obtained when the preset magnification value is a first magnification;

[0053] Figure 12 is a schematic diagram of a second grayscale image obtained when the preset magnification value is a second magnification;

[0054] Figure 13 This is a schematic diagram of a specific process of a pre-check method provided by an embodiment of the present invention;

[0055] Figure 14 This is a schematic diagram of a specific process for generating a grayscale image during a pre-inspection process provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0057] It will be apparent to those skilled in the art that various modifications and variations can be made in this application without departing from the spirit or scope of this application. Therefore, this application is intended to cover modifications and variations of this application that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents. It should be noted that the embodiments provided in the examples of this application can be combined with each other without contradiction.

[0058] First, it should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the ordinary meaning understood by a person of ordinary skill in the field to which the present invention belongs. The terms "first," "second," and similar terms used in the present invention do not indicate any order, quantity, or importance, but are simply used to distinguish different components. "Include" and similar terms mean that the elements or objects preceding the term include the elements or objects listed after the term and their equivalents, but do not exclude other elements or objects. "Connected" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," and "right," and similar terms are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In addition, the shapes and sizes of the components in the drawings do not reflect the actual proportions and are intended only to illustrate the contents of the present invention.

[0059] Figure 1 1 is a schematic structural diagram of a pre-inspection system of an electron gun provided by an embodiment of the present invention when performing pre-inspection work. Figure 2 yes Figure 1 The schematic diagram of the structure of the measuring lens barrel in the pre-inspection system is shown in FIG. Figure 1 and Figure 2As shown, the pre-inspection system provided by the embodiment of the present invention includes a deflection lens barrel 2, a measuring lens barrel 3 and a control module 4; the measuring lens barrel 3 is located directly below the deflection lens barrel 2, and the deflection lens barrel 2 and the measuring lens barrel 3 are electrically connected to the control module 4 respectively; the measuring lens barrel 3 includes an aperture 31 and an electron beam collecting device 32, the center of the aperture 31 has a light-transmitting hole 311, and the electron beam collecting device 32 is located directly below the aperture 31; during pre-inspection, the electron gun lens barrel 1 to be inspected is installed directly above the deflection lens barrel 2, and the control module 4 is electrically connected to the electron gun lens barrel 1; the electron gun lens barrel 1 includes an electron gun.

[0060] Among them, the control module 4 is used to control the electron gun to emit an electron beam, and to control the deflection of the electron beam in the first direction and the second direction through the deflection lens barrel 2, so that the electron beam scans the first scanning range point by point; the first direction and the second direction are orthogonal and both parallel to the plane where the aperture is located; the position of the electron gun is also the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction.

[0061] Among them, the electron beam collecting device 32 is used to collect the current value corresponding to each scanning point of the electron beam during the scanning process, and send the current value to the control module 4; the control module 4 is also used to generate a grayscale image based on the current value, and adjust the position of the electron gun according to the position of the bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical axis; the bright spot corresponds to the imaging area of ​​the light-transmitting hole.

[0062] For example, Figure 3 This is a schematic diagram of the structure of a typical electron gun lens barrel. Figure 3 As shown, the electron gun barrel 1 includes a barrel wall 12, with a removable sealing cover 13 located above the barrel wall 12. An insulating sleeve 14 is positioned between the barrel wall 12 and the sealing cover 13. A cathode filament 16 of the electron gun is secured to the insulating sleeve 14. Electrodes within the insulating sleeve 14 apply voltage to the electron gun, causing it to emit an electron beam. The sealing cover 13 and the insulating sleeve 14 are securely connected by a foldable sealing material 15, such as a stainless steel bellows, to isolate and seal the interior of the chamber from the outside. During pre-inspection, the electron gun barrel is mounted directly above the deflection barrel 2, and a control module 4 is electrically connected to the barrel 1, enabling the control module to control the electron gun's electron beam emission.

[0063] In this embodiment, the deflection lens barrel 2 is used to realize the deflection of the electron beam so that the electron beam scans a certain area. Its working principle is similar to the deflection principle of the electron beam controlled by a scanning electron microscope.

[0064] For example, Figure 4 yes Figure 1 The schematic diagram of the top view of the deflection lens barrel in the pre-inspection system is shown in FIG. Figure 4As shown, the deflection lens barrel 2 comprises a first deflection coil 211 and a second deflection coil 212; the control module is configured to control the deflection range of the electron beam in the first direction D1 by controlling the current of the first deflection coil 211; and the control module is further configured to control the deflection range of the electron beam in the second direction D2 by controlling the current of the second deflection coil 212. It can be understood that, since the first direction D1 and the second direction D2 are orthogonal, the shape of the first scanning range is rectangular or square, and the area of the above-mentioned first scanning range is the product of the maximum scanning range (distance) of the electron beam in the first direction and the maximum scanning range (distance) of the electron beam in the second direction. In addition, since the position of the electron gun is the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction, the center of the first scanning range is the position of the orthographic projection of the electron gun on the scanning surface (i.e. the diaphragm).

[0065] Further, the manner in which the electron beam performs point-by-point scanning on the first scanning range can be any one of line-by-line scanning, spiral scanning and snake scanning. It can be understood that the deflection degree of the electron beam in the first direction and / or the deflection degree of the electron beam in the second direction corresponding to different scanning points are different, and therefore the current of the first deflection coil (referred to as the first deflection current) and / or the current of the second deflection coil (referred to as the second deflection current) are different, in other words, each scanning point corresponds to a first deflection current and a second deflection current. As long as the first deflection current and the second deflection current of the electron beam when scanning each scanning point are determined respectively, and the current changes on the first deflection coil and the second deflection coil are controlled according to the scanning manner, the point-by-point scanning of the electron beam can be realized.

[0066] As shown in the figure, Figure 5 is another structure schematic diagram of a pre-check system provided by an embodiment of the present application, as shown in the figure, Figure 5 As shown, the control module 4 comprises a controller 41 and a deflection control circuit 43, the deflection control circuit 43 is connected between the deflection lens barrel 2 and the controller 41, specifically, the deflection control circuit 43 is electrically connected with the controller 41, the first deflection coil 211 and the second deflection coil 212 respectively, and the controller 41 can control the current of the first deflection coil 211 through the deflection control circuit 43, and control the current of the second deflection coil 212 through the deflection control circuit 43.

[0067] In addition, as shown in the figure, Figure 4 As shown, the deflection lens barrel 2 further comprises an electron beam channel 22, the electron beam channel 22 is sealed from the outside, and the electron beam passes through the electron beam channel 22 to reach the measurement lens barrel 3.

[0068] Further, in the embodiment, the pre-check system further comprises a measurement lens barrel, as shown in the figure, Figure 2As shown, the measuring lens barrel 3 includes an aperture 31 and an electron beam collecting device 32. The center of the aperture 31 has a light-transmitting hole 311. The electron beam collecting device 32 is located directly below the aperture 31. In this way, when the electron beam enters the measuring lens barrel and passes through the light-transmitting hole, the electron beam collecting device can collect the electrons. Otherwise, the electrons cannot be collected. Based on this, it can be understood that when the electron beam collects the current value corresponding to each scanning point of the electron beam during the scanning process through the electron beam collecting device in this embodiment, if the scanning point is located in the area where the light-transmitting hole is located, the current value collected by the electron beam collecting device 32 is greater than 0. If the scanning point is located outside the area where the light-transmitting hole is located, the electron beam is blocked by the aperture 31, and the current value collected by the electron beam collecting device 32 is 0.

[0069] Furthermore, the control module 4 can generate a grayscale image based on the current value, and adjust the position of the electron gun according to the position of the bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical axis; the bright spot corresponds to the imaging area of ​​the light-transmitting hole.

[0070] The optical axis can be understood as the central axis of the light-transmitting hole. For example, a mapping relationship between current value and grayscale value can be established to determine the grayscale value of each pixel in the grayscale image according to the current value corresponding to each scanning point to generate a grayscale image.

[0071] Specifically, when the center of the bright spot coincides with the center of the image, the emission axis of the electron gun is aligned. The following describes the working principle of adjusting the position of the electron gun according to the position of the bright spot in the grayscale image to achieve emission axis alignment of the electron gun.

[0072] For example, Figure 6 This is one of the working principle diagrams of the pre-check system provided by the embodiment of the present invention. Figure 6 As shown, assuming that the emission axis of the electron gun coincides with the optical axis, at this time, by controlling the current of the deflection coil in one direction (for example, the first deflection coil) to change from -I to +I, the electron beam will move continuously in that direction (for example, the first direction). Due to the obstruction of the aperture 31, the current value Ip collected by the electron beam collecting device 32 will change. If the collected current value Ip is corresponded to the grayscale value of the image, a dark-bright-dark stripe will be formed.

[0073] Furthermore, Figure 7 This is the second schematic diagram of the working principle of the pre-inspection system provided by the embodiment of the present invention. Figure 7 Part (a) illustrates the relative positional relationship between the electron gun and the aperture, part (b) is a top view of the aperture 31, illustrating the first scanning range S1, and part (c) illustrates the grayscale image. Figure 7As shown in (a), (b) and (c), when the emission axis of the cathode filament 16 of the electron gun coincides with the optical axis L, if the current of the first deflection coil and the second deflection coil is controlled so that the electron beam scans the first scanning range S1 point by point, the center of the light-transmitting hole 311 coincides with the center of the first scanning range S1. Correspondingly, if the current value collected by the electron beam collecting device 32 corresponds to the grayscale value of the image, a grayscale image with a bright spot Q in the center will be generated, and the center of the bright spot Q coincides with the center of the image.

[0074] Furthermore, Figure 8 This is the third schematic diagram of the working principle of the pre-inspection system provided by the embodiment of the present invention. Figure 8 Part (a) illustrates the relative positional relationship between the electron gun and the aperture, part (b) is a top view of the aperture 31, illustrating the first scanning range S1, and part (c) illustrates the grayscale image. Figure 8 As shown in (a), (b) and (c), when the emission axis of the electron gun cathode filament 16 does not coincide with the optical axis L, if the first deflection coil and the second deflection coil are controlled to control the current so that the electron beam scans the first scanning range S1 point by point, the first scanning range S1 will shift due to the shift of the emission axis of the electron gun cathode filament 16, causing the relative position of the first scanning range S1 and the light-transmitting hole 311 to shift. Correspondingly, if the current value collected by the electron beam collecting device 32 is corresponded to the grayscale value of the image, the position of the bright spot Q in the image will shift synchronously. Figure 8 For example, when the emission axis of the electron gun cathode filament 16 deviates to the left of the optical axis L, the center of the first scanning range S1 will also deviate to the left of the center of the light-transmitting hole 311, thereby causing the center of the bright spot Q in the grayscale image to deviate to the right of the image center.

[0075] It can be seen that the position of the bright spot in the grayscale image corresponds to the light-transmitting hole, and the relative positional relationship between the center of the bright spot and the center of the image can reflect the relative positional relationship between the center of the light-transmitting hole and the center of the first scanning range of the actual scan. Then, the position of the electron gun can be adjusted according to the offset of the bright spot. As long as the center of the bright spot is adjusted to the center of the image, the emission axis of the electron gun can be coincident with the optical axis, and the emission axis alignment operation of the electron gun can be achieved, which is simple and intuitive.

[0076] Here, the image center is the center of the grayscale image. The size of the grayscale image (resolution / pixel setting) is usually unchanged, so the image center is fixed. However, it should be noted that the grayscale image is updated in real time. Specifically, in the process of adjusting the position of the electron gun, the scanning process is carried out synchronously, so that the relative position relationship between the first scanning range and the light-transmitting hole changes in real time. Therefore, the grayscale image is updated in real time, which is specifically reflected in the different relative positions of the center of the bright spot and the center of the grayscale image in different grayscale images. It is easy to understand that since the scanning process and the imaging process are very fast, in the process of adjusting the position of the electron gun to align the emission axis, the operator sees a continuous video (composed of frames of grayscale images), and the center of the bright spot in the video is constantly moving toward the center.

[0077] It is understandable that the electron gun emission axis alignment operation performed using the technical solution of the embodiments of the present invention does not require knowledge of the specific position of the first scanning range. Alignment of the electron gun emission axis can be achieved by simply adjusting the position of the electron gun to move the bright spot in the grayscale image, ultimately aligning the center of the bright spot with the center of the image. It should be noted that the structures of different electron gun barrels vary, and the direction of electron gun position adjustment is not necessarily related to the direction of bright spot movement. For different electron gun barrels, the direction of electron gun movement can be determined through several attempts.

[0078] Understandably, a grayscale image may not contain a bright spot. For example, if the electron gun's position deviates significantly, causing the first scanning range to not cover the light-transmitting aperture, the grayscale image may lack a bright spot. In this case, the electron gun's position can be adjusted to find the bright spot again. Furthermore, if the electron gun malfunctions, the grayscale image may also lack a bright spot. In this case, even repeated adjustments to the electron gun's position will not reveal the bright spot. Therefore, during the electron gun's emission axis alignment process, the electron gun's quality can also be tested.

[0079] In summary, the pre-inspection system provided by the embodiment of the present invention can complete pre-inspection work such as alignment of the emission axis of the electron gun and quality inspection. After the pre-inspection is completed, the electron gun barrel can be installed as a whole in the scanning equipment. In this way, the disadvantages of on-site replacement of the cathode filament can be avoided (for example, avoiding the problems of complex, time-consuming and difficult on-site alignment operations, avoiding the problem of a large amount of time wasted due to the installation of defective products, and avoiding the problem of damage to the cathode filament due to transportation and disassembly). In addition, since the emission axis of the electron gun has completed the preliminary alignment operation, only fine-tuning of the on-site scanning electron microscope equipment is required, which can avoid searching for the light spot in a large area, improve the maintenance efficiency of the electron microscope equipment, reduce the difficulty of maintenance of the electron microscope equipment, and reduce the downtime of the electron microscope equipment.

[0080] like Figure 3As shown, the position of the electron gun refers to the position of the electron gun cathode filament 16. As an example, refer to Figure 3 The sealing cover 13 is symmetrically provided with four adjusting top screws 17, and the angle between any two adjacent adjusting top screws is 90°. One end of the adjusting top screw 17 is in contact with the insulating sleeve 14. In this way, the control module can adjust the position of the electron gun cathode filament 16 in two orthogonal directions in the vacuum chamber by adjusting the extension length of the four adjusting top screws 17, that is, adjust the position of the electron gun.

[0081] It can be understood that the two orthogonal directions are the directions of the connecting lines of the two groups of opposite adjusting top screws 17. It should be noted that the two orthogonal directions can coincide with the first direction and the second direction respectively, or can not coincide with the first direction and the second direction respectively. There is no necessary connection between the two, and the position adjustment direction of the electron gun has no necessary connection with the moving direction of the bright spot.

[0082] It should be further noted that different types of electron gun lens barrels have different ways of adjusting the position of the cathode filament, which is not limited in the embodiment of the present application.

[0083] As shown in Figure 5 , optionally, the control module 4 further comprises a driving control circuit 42 connected between the electron gun lens barrel 1 and the controller 41. The driving control circuit 42 can be used to control a precision driver, such as a motor, to precisely adjust the position of the electron gun. As an example, referring to Figure 3 the structure of the electron gun lens barrel, the precision driver can be connected with the adjusting top screw 17, and the controller 41 controls the precision driver to adjust the extension length of the adjusting top screw 17 through the driving control circuit 42, so as to adjust the position of the electron gun cathode filament.

[0084] In addition, as shown in Figure 5 , optionally, the control module further comprises a measurement circuit 44 connected between the measurement lens barrel 3 and the controller 41. In the embodiment, the measurement circuit 44 is used to process the weak current signal collected by the electron beam collecting device, such as amplification, filtering, zero adjustment, etc. It can also convert the current signal into a voltage signal recognizable by the controller 41, and then convert the voltage value corresponding to the current value into a gray value and display it on the pixel point corresponding to the position of the gray scale image.

[0085] As shown in Figure 5As shown, the pre-check system also comprises a man-machine interaction module 5, which is electrically connected with the controller 41. In this embodiment, the man-machine interaction module can have a display function to display an operation interface, such as the movement of the electron gun and the position of the electron beam, and the operator can view the gray-scale image through the man-machine interaction module, and then move the bright spot in the gray-scale image by moving the electron gun until the center of the bright spot coincides with the center of the image, so as to realize the alignment operation of the emission axis of the electron gun.

[0086] Based on the same inventive concept, the present application also provides a pre-check method of an electron gun, which can be executed by the pre-check system provided by any of the embodiments of the present application. Figure 9 is a flowchart of a pre-check method of an electron gun provided by the present application, as shown in the figure, the pre-check method comprises the following steps: Figure 9

[0087] S101, controlling the electron gun to emit an electron beam.

[0088] Specifically, when pre-checking the electron gun, first install the electron gun lens barrel to be detected above the deflection lens barrel, and then electrically connect the electron gun lens barrel with the control module in the pre-check system. In this way, the control module can apply voltage to the electron gun to make the electron gun emit an electron beam.

[0089] S102, controlling the electron beam to deflect in a first direction and a second direction through the deflection lens barrel to make the electron beam perform point-by-point scanning on a first scanning range; the first direction and the second direction are orthogonal and both are parallel to the plane where the diaphragm is located; the position of the electron gun is the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction.

[0090] Specifically, in the process of emitting the electron beam by the electron gun, the control module controls the electron beam to deflect in a first direction and a second direction through the deflection lens barrel to make the electron beam perform point-by-point scanning on a first scanning range. It can be understood that the size of the first scanning range is related to the scanning distance of the electron beam in the first direction and the scanning distance of the electron beam in the second direction, and the product of the two is the area of the first scanning range, while the center of the first scanning range is related to the position of the electron gun, specifically, the center of the first scanning range is the orthographic projection position of the electron gun on the scanning surface.

[0091] S103, receiving the current value corresponding to each scanning point of the electron beam in the scanning process collected by the electron beam collecting device, and generating a gray-scale image based on the current value, and adjusting the position of the electron gun according to the position of the bright spot in the gray-scale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical optical axis; the bright spot corresponds to the imaging area of the light transmission hole.

[0092] ​Specifically, in the process that the electron beam scans the first scanning range point by point, the electron beam collecting device synchronously collects the current value corresponding to each scanning point, the control module receives the current value, and according to the mapping relationship between the current value and the gray value and the current value corresponding to each scanning point, the gray value of each pixel point in the gray image is determined, and the gray image is generated. It can be understood that if the scanning point is located in the region where the light transmission hole is located, the current value corresponding to the scanning point is greater than 0, and if the scanning point is located outside the region where the light transmission hole is located, the current value corresponding to the scanning point is 0.

[0093] Further, according to the above description of the working principle, the relative position relationship between the center of the bright spot and the center of the image can reflect the relative position relationship between the center of the light transmission hole and the center of the actual scanned first scanning range, and then the position of the electron gun can be adjusted according to the offset of the bright spot. As long as the center of the bright spot is adjusted to the center of the image, the emission axis of the electron gun can be aligned with the optical axis, and the emission axis alignment operation of the electron gun can be realized.

[0094] In addition, according to the above description, during the emission axis alignment operation of the electron gun, the quality of the electron gun can also be detected according to the presence or absence of the bright spot.

[0095] In summary, the pre-checking method provided by the embodiment of the present application can complete the pre-checking work such as the emission axis alignment and quality detection of the electron gun. After the pre-checking is completed, the electron gun lens barrel can be installed in the scanning equipment as a whole. In this way, the disadvantages of replacing the cathode filament on site can be avoided (for example, the problems of complex on-site alignment operation, long time consumption and difficult alignment can be avoided, the problem of a large amount of time waste caused by the installation of defective products can be avoided, and the problem of damage to the cathode filament caused by transportation and disassembly can be avoided). In addition, since the emission axis of the electron gun has completed the preliminary alignment operation, only fine tuning of the on-site scanning electron microscope equipment is required. Therefore, a large range of light spots can be avoided, the maintenance efficiency of the electron microscope equipment can be improved, the maintenance difficulty of the electron microscope equipment can be reduced, and the downtime of the electron microscope equipment can be reduced.

[0096] On the basis of the above embodiment, referring to Figure 4 The deflection lens barrel 2 includes a first deflection coil 211 and a second deflection coil 212. The control module can control the deflection range of the electron beam in the first direction D1 by controlling the current of the first deflection coil 211. The control module can also control the deflection range of the electron beam in the second direction D2 by controlling the current of the second deflection coil 212. Correspondingly, the above-mentioned deflection of the electron beam in the first direction and the second direction by the deflection lens barrel to make the electron beam scan the first scanning range point by point can include the following steps:

[0097] Step one, determining the first scanning step number of the first deflection coil and the second scanning step number of the second deflection coil according to the preset pixel value of the gray image.

[0098] Step two, according to the preset magnification value of the gray image, the first maximum current of the first deflection coil and the second maximum current of the second deflection coil are calculated;

[0099] Step three, the first current range is determined according to the first maximum current; wherein the first maximum current is XI1, the first current range is -XI1~+XI1; XI1 is a positive number;

[0100] Step four, the second current range is determined according to the second maximum current; wherein the second maximum current is YI1, the second current range is -YI1~+YI1; YI1 is a positive number;

[0101] Step five, the first deflection current corresponding to each scanning point in the first direction of the first deflection coil is calculated according to the first current range and the first scanning step number;

[0102] Step six, the second deflection current corresponding to each scanning point in the second direction of the second deflection coil is calculated according to the second current range and the second scanning step number;

[0103] Step seven, the current change of the first deflection coil is controlled according to the first deflection current corresponding to each scanning point, and the current change of the second deflection coil is controlled according to the second deflection current corresponding to each scanning point, so that the electron beam performs point-by-point scanning in the first scanning range.

[0104] In step one, the preset pixel value can be set by the user, the first scanning step number can be understood as the number of scanning points of the electron beam in the first direction, and the second scanning step number can be understood as the number of scanning points of the electron beam in the second direction.

[0105] It can be understood that the scanning points correspond to the pixel points one by one, the number of scanning points in each row can be determined according to the number of pixel points in each row (both are equal), the number of scanning points in each column can be determined according to the number of pixel points in each column (both are equal), and then the first scanning step number and the second scanning step number are determined. For example, the pixel value of the gray image can be M*N, wherein M and N are positive integers, M and N can be equal or not equal, M represents the number of pixel points in each row of the gray image, and N represents the number of pixel points in each column of the gray image. At this time, the first scanning step number can be M and the second scanning step number can be N.

[0106] In step two, the preset magnification value can be set by the user; the first maximum current refers to the current on the first deflection coil when the deflection degree of the electron beam in the first direction is maximum; the second maximum current refers to the current on the second deflection coil when the deflection degree of the electron beam in the second direction is maximum.

[0107] The magnification represents the ratio between the size of the gray scale image and the size of the first scanning range. Referring to photography, the larger the magnification, the smaller the actual photographed area for the same size of the photo (same pixel value). Similarly, in the present embodiment, for the same size of the gray scale image, the larger the magnification, the smaller the actual scanned area (i.e. the first scanning range). Therefore, according to the preset magnification value, the size of the first scanning range in the first direction and the second direction can be determined, and then according to the current change amount required by the scanning unit size, the current change amount required in the first direction and the second direction when scanning the first scanning range can be determined respectively, and then the first maximum current and the second maximum current can be determined. For example, assuming that the current change amount A required for scanning from one end of the first scanning range to the other end in the first direction, the first maximum current is XI = 0.5A, and assuming that the current change amount B required for scanning from one end of the first scanning range to the other end in the second direction, the second maximum current YI = 0.5B.

[0108] Further, in step three, according to the first maximum current XI1, the first current range is determined as -XI1~+XI1, so that when the current of the first deflection coil is changed in the range of -XI1~+XI1, the electron beam can be scanned in the first direction with the position of the electron gun as the center. Similarly, in step four, according to the second maximum current YI1, the second current range is determined as -YI1~+YI1, so that when the current of the second deflection coil is changed in the range of -YI1~+YI1, the electron beam can be scanned in the second direction with the position of the electron gun as the center, and then the center of the first scanning range can correspond to the position of the electron gun, which is convenient for subsequent alignment operation.

[0109] Furthermore, steps 5 and 6 are performed to calculate, based on the first current range and the first number of scan steps, a first deflection current corresponding to each scan point in the first direction for the first deflection coil, and based on the second current range and the second number of scan steps, a second deflection current corresponding to each scan point in the second direction for the second deflection coil. As described above, each scan point corresponds to a first deflection current and a second deflection current, and different scan points correspond to different first deflection currents and / or second deflection currents. Taking row-by-row scanning (the first direction is the row direction, and the second direction is the column direction) as an example, it can be understood that the scanning points in the same row correspond to the same second deflection current. When M scans are performed in the first direction, so that each row has M scanning points, the current in the first deflection coil needs to change (M-1) times. That is, the first current range -XI1 to +XI1 needs to be divided into (M-1) steps. The current change corresponding to each step is 2*X1 / (M-1). In this way, the first deflection current corresponding to the first scanning point in the first direction is -XI1. After that, each step change in the first deflection current corresponds to a scanning point. The first deflection current corresponding to the last scanning point in the first direction is +XI1. Similarly, specifically, -YI1~+YI1 is divided into (N-1) steps, and the current change corresponding to each step is 2*Y1 / (N-1). Then the second deflection current corresponding to the first scanning point in the second direction is -YI1, and then each step change of the second deflection current corresponds to a scanning point, and the second deflection current corresponding to the last scanning point in the second direction is +YI1, so that a total of N points are scanned in the second direction.

[0110] Finally, step seven is executed, i.e., the current change of the first deflection coil is controlled according to the first deflection current corresponding to each scanning point, and the current change of the second deflection coil is controlled according to the second deflection current corresponding to each scanning point, so that the electron beam can be scanned point by point within the first scanning range.

[0111] For example, Figure 10 This is a schematic diagram of a scanning principle provided by an embodiment of the present invention. Figure 10As shown, the deflection current corresponding to each scanning point is (XI, YI), where XI represents the first deflection current and YI represents the second deflection current. Taking left-to-right scanning as an example, the deflection current corresponding to the leftmost scanning point in the first row is (-XI1, -YI1), the deflection current corresponding to the rightmost scanning point in the first row is (+XI1, -YI1), and the second deflection current corresponding to the remaining scanning points in the first row is -Y1. The change in the first deflection current corresponding to two adjacent scanning points is the current change corresponding to each step size described above. The deflection current corresponding to the leftmost scanning point in the last row is (-XI1, +YI1), the deflection current corresponding to the rightmost scanning point in the last row is (+XI1, +YI1), and the currents corresponding to the remaining scanning points are similar and are not further described here. After determining the first and second deflection currents corresponding to each scanning point, the currents in the first and second deflection coils can be controlled to achieve line-by-line single-point scanning of the electron beam.

[0112] As described above, during the scanning process, the electron beam collecting device collects the current value corresponding to each scanning point, the control module receives the current value and generates a grayscale image based on the current value, and adjusts the position of the electron gun according to the position of the bright spot in the grayscale image to achieve the emission axis alignment operation of the electron gun. Figure 11 is a schematic diagram of a first grayscale image obtained when the preset magnification value is a first magnification, such as Figure 11 As shown, the preset pixel value of the image is k*k, and the first current range corresponding to the first magnification is Figure 10 The second current range corresponding to -XI1~+XI1 is Figure 10 It can be understood that the size of the first current range and the second current range can be used to represent the size of the actual scanning range. Figure 10 and Figure 11 It can be seen that when the scanning point is located within the light-transmitting hole 311, the electron beam can pass through the light-transmitting hole and be received by the electron beam collecting device, so that the current value collected by the electron beam collecting device is greater than 0, thereby forming a bright spot in the grayscale image ( Figure 11 Using a circular bright spot as an example, at other scanning positions, the electron beam collector is unable to collect current due to the aperture blocking the beam, resulting in dark areas in the grayscale image. Based on the principle explained above, the electron gun's emission axis can be aligned by adjusting the position of the electron gun so that the center of the bright spot coincides with the center of the image. This operation is simple and intuitive.

[0113] Reference Figure 11 , Optionally, in the grayscale image, the number of pixels in each row is equal to the number of pixels in each column. Exemplarily, Figure 11Taking the number of pixels in each row and the number of pixels in each column as k, that is, M=N=k as an example, such a setting is conducive to simplifying the calculation of the first deflection current and the second deflection current corresponding to each scanning point, thereby improving alignment efficiency.

[0114] Optionally, during the pre-inspection process, the preset magnification value is variable, and different grayscale images are obtained based on different preset magnification values. According to the above description, different preset magnification values ​​make the first current range and the second current range different, that is, the first scanning range is different, and thus the obtained grayscale images are different.

[0115] Further optionally, adjusting the position of the electron gun according to the position of the bright spot in the grayscale image may include the following steps:

[0116] Setting the preset magnification value to a first magnification to obtain a first grayscale image;

[0117] Determine whether there is a bright spot in the first grayscale image; if not, adjust the position of the electron gun, and again determine whether there is a bright spot in the updated first grayscale image; if so, adjust the position of the electron gun so that the center of the bright spot moves toward the center of the image;

[0118] The preset magnification value is set to the second magnification to obtain a second grayscale image, and the position of the electron gun is adjusted until the center of the bright spot coincides with the center of the image;

[0119] The first magnification is smaller than the second magnification.

[0120] Among them, the process of setting the preset magnification value to the first magnification to obtain the first grayscale image, and the process of setting the preset magnification value to the second magnification to obtain the second grayscale image can refer to the above description and will not be repeated here.

[0121] The term "first grayscale image" generally refers to a grayscale image obtained at the first magnification. As previously explained, adjusting the electron gun position at the first magnification updates the first grayscale image. The position of the bright spot in the updated first grayscale image changes, while the size of the bright spot remains unchanged (because the magnification remains unchanged). Of course, the image center remains unchanged (because the pixel value remains unchanged).

[0122] When the preset magnification value is the first magnification, specifically, when it is determined that a bright spot exists in the first grayscale image and the center of the bright spot does not coincide with the center of the image, the position of the electron gun is adjusted so that the center of the bright spot moves toward the direction close to the center of the image, and the emission axis alignment operation of the electron gun is performed; when it is determined that no bright spot exists in the first grayscale image, the position of the electron gun is adjusted and the first grayscale image is updated. If a bright spot exists in the updated first grayscale image, the position of the electron gun is continued to be adjusted so that the center of the bright spot moves toward the direction close to the center of the image, and the emission axis alignment operation of the electron gun is performed.

[0123] For example, refer to Figure 10 and Figure 11 Since the first magnification is small, the scanning range corresponding to the first grayscale image obtained at the first magnification is large (the first current range is -XI1 to +XI1, and the second current range is -YI1 to +YI1), so it is easy to include the light-transmitting hole 311 of the aperture in the scanning range, and then find the bright spot in the grayscale image, adjust the position of the electron gun according to the position of the bright spot, and perform the emission axis alignment operation; even if the light-transmitting hole 311 is not included in the scanning range, it is beneficial to make the scanning range close to the light-transmitting hole 311, find the bright spot in the grayscale image by fine-tuning the position of the electron gun, and then perform the emission axis alignment operation of the electron gun.

[0124] Further, refer to Figure 11 Because the first magnification is relatively low, the bright spot size is relatively small. Therefore, if the center of the bright spot is simply aligned with the center of the grayscale image in the first grayscale image obtained at the first magnification, it may be difficult to ensure accurate alignment between the two. To further ensure alignment accuracy, this embodiment first obtains a first grayscale image at the first magnification. Based on the position of the bright spot in the first grayscale image, the electron gun position is initially adjusted to bring the center of the bright spot closer to the image center. Then, a second grayscale image is obtained at a higher second magnification. Based on the position of the bright spot in the second grayscale image, the electron gun position is further adjusted to bring the center of the bright spot into alignment with the image center, thereby improving emission axis alignment accuracy.

[0125] The second grayscale image generally refers to a grayscale image obtained at the second magnification. During the process of adjusting the position of the electron gun, the second grayscale image is also updated in real time.

[0126] Based on the above description, it can be understood that after adjusting the preset magnification value, the control module needs to recalculate the first maximum current and the second maximum current, re-determine the first current range and the second current range, and control the current changes in the first deflection coil and the second deflection coil to make the electron beam scan the new scanning range, thereby obtaining a new grayscale image. Therefore, the bright spot size in the grayscale image at different magnifications is different. For example, Figure 12 The grayscale image is obtained when the preset magnification value is the second magnification, and the corresponding first current range is, for example, Figure 10 The second current range of -XI2~+XI2 is Figure 10 The calculation method of -YI2~+YI2 in is as described above and will not be repeated here. Figure 11 and Figure 12 It can be seen that since the pixel value of the grayscale image remains unchanged, the first grayscale image (such as Figure 11 ) and the second grayscale image (such as Figure 12The size of the actual scanning area is reduced by the magnification, so that the bright spot in the gray scale image can be enlarged, and fine adjustment is facilitated, so that the center of the bright spot is accurately overlapped with the center of the image, and the alignment accuracy of the emission axis is improved.

[0127] Optionally, the pre-checking method further comprises: when the preset magnification value is the first magnification, if the bright spot still does not exist in the updated first gray scale image, determining that the electron gun is faulty. Specifically, under the first lower magnification, if it is determined that the bright spot does not exist in the initial first gray scale image, and after adjusting the position of the electron gun and updating the first gray scale image, the bright spot still cannot be found in the image, it is determined that the electron gun is faulty. According to the foregoing description, since the first magnification is relatively low, the scanning range is relatively large, and even if the light transmission hole is not included in the scanning range, it is also beneficial to make the scanning range close to the light transmission hole, and the position of the electron gun is adjusted to find the bright spot in the gray scale image, but if the bright spot still cannot be found after adjusting the position of the electron gun, it is likely that the electron gun itself is faulty. Therefore, the quality of the electron gun can be detected synchronously during the alignment of the emission axis of the electron gun, the pre-checking efficiency is improved, and a large amount of time is avoided from being wasted due to the on-site installation of defective products.

[0128] An exemplary Figure 13 is a specific flowchart of a pre-checking method provided by an embodiment of the present application, which summarizes the execution process of the pre-checking work such as the alignment and quality detection of the emission axis of the electron gun. As shown in Figure 13 , in the pre-checking process, a low magnification image is first generated, and the bright spot is searched in the low magnification image. If the bright spot exists and is centered, it indicates that the emission axis of the electron gun is in an aligned state, and the alignment operation can be ended. If the bright spot exists but is not centered, the position of the electron gun is first adjusted to make the bright spot close to the center of the image, and then the magnification of the image is adjusted to generate a high magnification image, and the position of the electron gun is adjusted in the high magnification image until the bright spot is centered, and the alignment operation is ended. If the bright spot is not observed in the low magnification image, the position of the electron gun is adjusted. If the position of the electron gun is adjusted for several times and the bright spot can be observed in the low magnification image, the above operation is performed until the bright spot is centered and the alignment operation is ended. If the number of times of adjusting the position of the electron gun is too large and the bright spot still cannot be observed in the low magnification image, it is determined that the electron gun is faulty, and the pre-checking is ended.

[0129] According to the foregoing description, in the Figure 13 , the gray scale image is updated in real time no matter whether the position of the electron gun is adjusted or the magnification of the image is adjusted. An exemplary Figure 14 is a specific flowchart of generating a gray scale image in a pre-checking process provided by an embodiment of the present application, so as to understand the image updating process. Referring to Figure 14As shown, the flow is as follows: a. reading the pixel settings of the user (the number of scanning steps can be determined according to the pixel settings); b. reading the magnification settings of the user (the current variation range of each deflection coil can be determined according to the magnification settings); c. deflection control (determining the first current on the first deflection coil and the second current on the second deflection coil corresponding to each scanning point according to the number of scanning steps and the current variation range, performing deflection control to make the electron beam scan point by point); d. current collection (i.e. while deflection control, the electron beam collection device collects the current value of the electron beam passing through the light aperture of the diaphragm to determine the current value corresponding to each scanning point); e. image generation (convert the current value to a gray value and display it on the pixel point at the corresponding position, i.e. a gray scale image can be generated). By repeatedly executing the above b, c, d and e, the real-time update of the gray scale image is realized.

[0130] In some embodiments, the quality detection of the electron gun can also be in the following manner. Optionally, the pre-checking method further comprises: after the center of the bright spot coincides with the center of the image, receiving the first current value of the electron beam passing through the light aperture collected by the electron beam collection device, and determining that the electron gun is faulty when the difference between the first current value and the standard current value is greater than a preset threshold.

[0131] Wherein, the specific values of the standard current value and the preset threshold can be set by oneself, and the embodiments of the present application do not limit this. Generally, the current value of the electron beam that can pass through the light aperture has a reference standard value, and if the difference between the first current value actually collected and the standard value is too large, for example, greater than the preset threshold, it can be determined that the electron gun is defective.

[0132] It should be noted that the quality detection of the electron gun can adopt at least one of the above two ways, and the embodiments of the present application do not limit this.

[0133] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A pre-inspection system for an electron gun, characterized in that: include: Deflecting lens tube, measuring lens tube and control module; The measuring lens barrel is located directly below the deflecting lens barrel, and the deflecting lens barrel and the measuring lens barrel are electrically connected to the control module respectively; the measuring lens barrel includes an aperture and an electron beam collecting device, the aperture has a light-transmitting hole at its center, and the electron beam collecting device is located directly below the aperture; During pre-inspection, the electron gun barrel to be inspected is installed directly above the deflection barrel, and the control module is electrically connected to the electron gun barrel; the electron gun barrel includes an electron gun; The control module is used to control the electron gun to emit an electron beam, and is used to control the deflection of the electron beam in a first direction and a second direction through the deflection lens barrel, so that the electron beam scans a first scanning range point by point; the first direction and the second direction are orthogonal to each other and are both parallel to the plane where the aperture is located; the position of the electron gun is simultaneously the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction; The electron beam collecting device is used to collect the current value corresponding to each scanning point of the electron beam during the scanning process, and send the current value to the control module; The control module is further configured to generate a grayscale image based on the current value, and adjust the position of the electron gun according to the position of a bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, thereby aligning the emission axis of the electron gun with the optical axis; the bright spot corresponds to an imaging area of ​​the light-transmitting hole.

2. The pre-inspection system according to claim 1, characterized in that: The deflection lens barrel includes a first deflection coil and a second deflection coil; the control module is used to control the deflection range of the electron beam in the first direction by controlling the current of the first deflection coil; the control module is also used to control the deflection range of the electron beam in the second direction by controlling the current of the second deflection coil.

3. The pre-inspection system according to claim 1, characterized in that: The control module includes a controller, a drive control circuit, a deflection control circuit and a measurement circuit; The drive control circuit is connected between the electron gun barrel and the controller; The deflection control circuit is connected between the deflection lens barrel and the controller; The measuring circuit is connected between the measuring lens barrel and the controller.

4. The pre-inspection system according to claim 3, characterized in that: The pre-inspection system further includes a human-computer interaction module, and the human-computer interaction module is electrically connected to the controller.

5. A pre-inspection method for an electron gun, performed by using the pre-inspection system according to any one of claims 1 to 4, characterized in that: The pre-check method comprises: Control the electron gun to emit electron beam; The electron beam is controlled to be deflected in a first direction and a second direction by a deflection lens barrel, so that the electron beam scans a first scanning range point by point; the first direction and the second direction are orthogonal to each other and are both parallel to the plane where the aperture is located; the position of the electron gun is simultaneously the center of the deflection range of the electron beam in the first direction and the center of the deflection range of the electron beam in the second direction; Receive the current value corresponding to each scanning point of the electron beam during the scanning process collected by the electron beam collection device, generate a grayscale image based on the current value, and adjust the position of the electron gun according to the position of the bright spot in the grayscale image until the center of the bright spot coincides with the center of the image, so that the emission axis of the electron gun coincides with the optical axis; the bright spot corresponds to the imaging area of ​​the light-transmitting hole.

6. The pre-check method according to claim 5, characterized in that: The deflection lens barrel includes a first deflection coil and a second deflection coil; controlling the electron beam to deflect in the first direction and the second direction by the deflection lens barrel so that the electron beam scans the first scanning range point by point includes: determining a first scanning step number of the first deflection coil and a second scanning step number of the second deflection coil according to a preset pixel value of the grayscale image; calculating a first maximum current of the first deflection coil and a second maximum current of the second deflection coil according to a preset magnification value of the grayscale image; Determine a first current range according to the first maximum current; wherein the first maximum current is XI1, the first current range is -XI1 to +XI1; XI1 is a positive number; Determine a second current range according to the second maximum current; wherein the second maximum current is YI1, the second current range is -YI1 to +YI1; YI1 is a positive number; calculating, according to the first current range and the first number of scanning steps, a first deflection current of the first deflection coil corresponding to each scanning point in the first direction; calculating, according to the second current range and the second number of scanning steps, a second deflection current of the second deflection coil corresponding to each scanning point in the second direction; The current change of the first deflection coil is controlled according to the first deflection current corresponding to each scanning point, and the current change of the second deflection coil is controlled according to the second deflection current corresponding to each scanning point, so that the electron beam scans point by point within the first scanning range.

7. The pre-check method according to claim 6, characterized in that: In the grayscale image, the number of pixels in each row is equal to the number of pixels in each column.

8. The pre-check method according to claim 6, characterized in that: During the pre-inspection process, the preset magnification value is variable, and the grayscale images obtained based on different preset magnification values ​​are different.

9. The pre-check method according to claim 8, characterized in that: Adjusting the position of the electron gun according to the position of the bright spot in the grayscale image includes: Setting the preset magnification value to a first magnification to obtain a first grayscale image; determining whether a bright spot exists in the first grayscale image; if not, adjusting the position of the electron gun, and again determining whether a bright spot exists in the updated first grayscale image; if so, adjusting the position of the electron gun so that the center of the bright spot moves toward the center of the image; Setting the preset magnification value to a second magnification to obtain a second grayscale image, and adjusting the position of the electron gun until the center of the bright spot coincides with the center of the image; The first magnification is smaller than the second magnification.

10. The pre-check method according to claim 9, characterized in that: The pre-check method further comprises: When the preset magnification value is the first magnification, if there is still no bright spot in the updated first grayscale image, it is determined that the electron gun is faulty; and / or, After the center of the bright spot coincides with the center of the image, a first current value of the electron beam passing through the light-transmitting hole collected by the electron beam collecting device is received. If the difference between the first current value and the standard current value is greater than a preset threshold, it is determined that the electron gun is faulty.

Images