Pre-inspection system and pre-inspection method of electron gun

Abstract

The invention discloses a pre-detection system and a pre-detection method for an electronic gun. The pre-detection system comprises a deflection lens cone, a measurement lens cone and a control module, the measuring lens cone and the deflection lens cone are respectively and electrically connected with the control module; during pre-detection, the to-be-detected electron gun lens cone is installed right above the deflection lens cone, and the control module is electrically connected with the electron gun lens cone. The control module is used for controlling the electron gun to emit an electron beam and controlling the electron beam to deflect in a first direction and a second direction through the deflection lens cone, so that the electron beam performs point-by-point scanning on a first scanning range; an electron beam collecting device in the measuring barrel lens is used for collecting a current value corresponding to each scanning point, and the control module is further used for generating a grayscale image based on the current values and adjusting the position of the electron gun according to the position of a hot spot in the grayscale image until the center of the hot spot coincides with the center of the image. The maintenance efficiency of the electron microscope equipment can be improved, the maintenance difficulty is reduced, and the downtime is shortened.

Description

Technical Field

[0001] The 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] The electron beam scanning measuring instrument is the core measuring equipment of the semiconductor manufacturing industry. It controls the electron gun to emit a high-energy electron beam through a high-voltage power supply, and then controls the electron beam to bombard the sample surface through the deflection coil and the convergence coil. The excited secondary electrons are detected to obtain the image information of the sample surface, so as to measure the key dimensions of the sample with high precision based on the clear surface image information. The cathode filament of the electron gun will produce loss during operation and needs to be replaced regularly. Due to errors such as machining and assembly, the replacement of the electron gun filament will cause the center of the electron beam (emission axis) to deviate from the central axis (optical axis) of each level of aperture, resulting in increased astigmatism, reduced 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 overlap of the electron beam emitted by the cathode filament of the electron gun with the central axis of the electron optical system, which is referred to as alignment or axis co-ordination.

[0003] At present, the replacement of the cathode filament of the electron gun is often carried out on-site. The old filament needs to be removed on-site. In this process, the vacuum of the vacuum chamber must be destroyed. After the new filament is installed, a high vacuum is established and the electron gun emission axis is aligned. However, in order to ensure that the electron optical system of the electron microscope can work normally and stably, an ultra-high vacuum degree is required inside the electron gun and the lens barrel. The establishment of ultra-high vacuum degree is complicated and time-consuming. Moreover, due to the measurement principle of the scanning electron microscope (magnification of thousands), it is difficult to find the alignment spot, which makes on-site alignment very difficult. In addition, the filament has the characteristics and requirements of high precision and high cleanliness. It is very easy to be damaged and contaminated during processing, transportation, and installation. If the filament is found to be defective after on-site replacement, the above replacement process can only be repeated, which consumes a lot of time and manpower. Summary of the invention

[0004] The 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 comprises 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 the 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;

[0008] The control module is used to control the electron gun to emit an electron beam, and is used to control the electron beam to deflect in a first direction and a second direction through a deflection lens barrel, so that the electron beam scans the first scanning range point by point; the first direction and the second direction are orthogonal and both are 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 by a pre-inspection system provided by any embodiment of the present invention, and the pre-inspection method includes:

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

[0019] The electron beam is controlled to deflect in a first direction and a second direction by a deflection lens barrel, so that the electron beam scans the first scanning range point by point; the first direction and the second direction are orthogonal and 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;

[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, and 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, including:

[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 the 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] 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 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 scanning step number;

[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] 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 yes, adjust 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, 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.

[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 device. 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 a large amount of time wasted due to the installation of defective products, and avoiding 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 light spots in a large range, 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 contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily 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 It is a structural schematic diagram of a pre-inspection system of 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;

[0044] Figure 3 It is a schematic diagram of the structure of a typical 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 schematic structural diagram of another pre-check 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 the embodiment of the present invention;

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

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

[0050] Fig. 9 It is a flow chart of a pre-inspection method of an electron gun provided by an embodiment of the present invention;

[0051] Fig.10 It is a schematic diagram of a scanning principle provided by an embodiment of the present invention;

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

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

[0054] Fig.13 It is a specific flow chart of a pre-check method provided by an embodiment of the present invention;

[0055] Fig.14 It is a schematic diagram of a specific process of 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 scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

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

[0058] First of all, it should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left" and "right" and similar words 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 accompanying drawings do not reflect the true proportions, and the purpose is only to illustrate the content of the present invention.

[0059] Figure 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 is used to control the deflection of the electron beam in the first direction and the second direction through the deflection lens tube 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 are 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.

[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, a detachable sealing cover 13 is arranged above the barrel wall 12, an insulating sleeve 14 is arranged between the barrel wall 12 and the sealing cover 13, and an electron gun cathode filament 16 is fixed on the insulating sleeve 14. Through the electrode in the insulating sleeve 14, a voltage can be applied to the electron gun to make the electron gun emit an electron beam. The sealing cover 13 and the insulating sleeve 14 are fixedly connected by a foldable sealing material 15, such as a stainless steel bellows, so that the cavity is isolated and sealed from the outside. When performing a pre-inspection, the electron gun barrel is installed directly above the deflection barrel 2, and the control module 4 is electrically connected to the electron gun barrel 1, so that the control module controls the electron gun to emit an electron beam.

[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, optionally, the deflection lens barrel 2 includes a first deflection coil 211 and a second deflection coil 212; the control module is used to 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 is also used 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 a rectangle or a square, and the area of ​​the 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 both 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 positive projection of the electron gun on the scanning surface (i.e., the aperture).

[0065] Furthermore, the electron beam may scan the first scanning range point by point in any of the following ways: line-by-line scanning, spiral scanning, and serpentine scanning. It is understandable that the deflection degree of the electron beam in the first direction and / or the deflection degree in the second direction corresponding to different scanning points are different, so 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 when the electron beam scans 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 mode, the electron beam can be scanned point by point.

[0066] For example, Figure 5 is a schematic diagram of the structure of another pre-check system provided by an embodiment of the present invention, such as Figure 5 As shown, the control module 4 includes 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 to the controller 41, the first deflection coil 211 and the second deflection coil 212 respectively. 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, if Figure 4 As shown, the deflection lens tube 2 further includes an electron beam channel 22 , which is sealed from the outside, and the electron beam reaches the measurement lens tube 3 through the electron beam channel 22 .

[0068] Furthermore, in this embodiment, the pre-inspection system also includes a measuring lens barrel, such as 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, and the electron beam collecting device 32 is located directly below the aperture 31, so that 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 in the scanning process collects the current value corresponding to each scanning point of the electron beam through the electron beam collecting device, 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, and 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. Exemplarily, 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 the emission axis alignment of the electron gun.

[0072] For example, Figure 6 FIG. 1 is one of the schematic diagrams of the working principle 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 corresponding to the grayscale value of the image, a dark-bright-dark stripe will be formed.

[0073] Further, Figure 7 This is the second schematic diagram of the working principle of the pre-check system provided by the embodiment of the present invention. Figure 7 Part (a) illustrates the relative position 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 electron gun 16 coincides with the optical axis L, if the electron beam scans the first scanning range S1 point by point by controlling the current of the first deflection coil and the second deflection coil, 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] Further, Figure 8 This is the third schematic diagram of the working principle of the pre-check system provided by the embodiment of the present invention. Figure 8 Part (a) illustrates the relative position 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 16 does not coincide with the optical axis L, if the first deflection coil and the second deflection coil are controlled by current so that the electron beam scans the first scanning range S1 point by point, the first scanning range S1 is offset due to the offset of the emission axis of the electron gun 16, so that the relative position of the first scanning range S1 and the light-transmitting hole 311 will be offset. Correspondingly, if the current value collected by the electron beam collecting device 32 corresponds to the gray value of the image, the position of the bright spot Q in the image will be synchronously offset. Figure 8 For example, when the emission axis of the electron gun 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, and the center of the bright spot Q in the grayscale image will 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 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-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 realized, which is simple and intuitive.

[0076] Among them, 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 that the relative position of the center of the bright spot in different grayscale images and the center of the grayscale image is different. It is easy to understand that since the scanning process and the imaging process are very fast, therefore, in the process of adjusting the position of the electron gun for emission axis alignment, 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 can be understood that the emission axis alignment operation of the electron gun is performed by using the technical solution of the embodiment of the present invention, without knowing the specific position of the first scanning range, and the emission axis alignment operation of the electron gun can be achieved by only adjusting the position of the electron gun to move the position of the bright spot in the grayscale image, and finally making the center of the bright spot coincide with the center of the image. It should be noted that the structures of different electron gun barrels are different, and the position adjustment direction of the electron gun is not necessarily related to the moving direction of the bright spot. For different electron gun barrels, the moving direction of the electron gun can be determined through several attempts.

[0078] It is understandable that there may be a situation where there is no bright spot in the grayscale image. Exemplarily, when the position deviation of the electron gun is too large so that the first scanning range does not cover the light-transmitting hole, there is no bright spot in the grayscale image. At this time, the bright spot can be found again by adjusting the position of the electron gun. In addition, if the electron gun fails, there is no bright spot in the grayscale image. At this time, even if the position of the electron gun is adjusted multiple times, the bright spot cannot be found in the grayscale image. Therefore, during the emission axis alignment operation of the electron gun, the quality of the electron gun can also be tested.

[0079] In summary, the pre-inspection system provided in the embodiment of the present invention can be used to 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 device. 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 a large amount of time wasted due to the installation of defective products, and avoiding 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, it is only necessary to fine-tune the on-site scanning electron microscope equipment, which can avoid searching for light spots 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 above adjustment of the position of the electron gun specifically refers to adjusting the position of the electron gun cathode filament 16. For example, referring to Figure 3 Four adjusting screws 17 are symmetrically arranged above the sealing cover 13, and the angle between any two adjacent adjusting screws is 90°. One end of the adjusting screw 17 contacts the insulating sleeve 14. In this way, the control module can adjust the position of the cathode filament 16 of the electron gun in the vacuum chamber in two orthogonal directions by adjusting the extension length of the four adjusting screws 17, that is, adjust the position of the electron gun.

[0081] It can be understood that the above two orthogonal directions are the connection directions of two sets of opposite adjustment filaments 17. It should be noted that the two orthogonal directions may or may not coincide with the first direction and the second direction respectively, and there is no necessary connection between the two directions. The position adjustment direction of the electron gun has no necessary connection with the moving direction of the bright spot.

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

[0083] like Figure 5 As shown, the control module 4 may further include a drive control circuit 42, which is connected between the electron gun barrel 1 and the controller 41. The drive control circuit 42 may be used to control a precision driver, such as a motor, to precisely adjust the position of the electron gun. Figure 3 Taking the structure of the electron gun barrel as an example, the precision driver can be connected to the adjusting top screw 17, and the controller 41 controls the precision driver through the driving control circuit 42 to adjust the extension length of the adjusting top screw 17, thereby adjusting the position of the cathode filament of the electron gun.

[0084] In addition, if Figure 5 As shown, optionally, the control module further includes a measuring circuit 44, and the measuring circuit 44 is connected between the measuring lens barrel 3 and the controller 41. In this embodiment, the measuring circuit 44 is used to process the weak current signal collected by the electron beam collecting device, such as amplification, filtering, zeroing, etc., and 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 grayscale value, which is displayed on the pixel point at the corresponding position of the grayscale image.

[0085] like Figure 5As shown, optionally, the pre-inspection system further includes a human-computer interaction module 5, which is electrically connected to the controller 41. In this embodiment, the human-computer interaction module may have a display function to display an operation interface, such as electron gun movement and electron beam position, etc. The operator may view the grayscale image through the human-computer interaction module, and then move the electron gun to move the bright spot position in the grayscale image until the center of the bright spot coincides with the center of the image, thereby realizing the emission axis alignment operation of the electron gun.

[0086] Based on the same inventive concept, an embodiment of the present invention further provides a pre-inspection method for an electron gun, and the pre-inspection method can be executed by using the pre-inspection system provided by any embodiment of the present invention. Fig. 9 is a flow chart of a pre-inspection method of an electron gun provided by an embodiment of the present invention, such as Fig. 9 As shown, the pre-check method includes the following steps:

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

[0088] Specifically, when pre-checking the electron gun, the electron gun barrel to be checked is first installed directly above the deflection barrel, and then the electron gun barrel is electrically connected to 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 the first direction and the second direction through the deflection lens barrel so that the electron beam scans the first scanning range point by point; the first direction and the second direction are orthogonal and both are 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.

[0090] Specifically, in the process of the electron gun emitting the electron beam, the control module controls the electron beam to deflect in the first direction and the second direction through the deflection lens barrel, so that the electron beam scans the first scanning range point by point. 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, and 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 positive 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 collected by the electron beam collecting device during the scanning process, generating a grayscale image based on the current value, and adjusting 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.

[0092] Specifically, in the process of the electron beam scanning 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 determines the grayscale value of each pixel in the grayscale image according to the mapping relationship between the current value and the grayscale value, and the current value corresponding to each scanning point, and generates a grayscale image. It can be understood that if the scanning point is located in the area where the light-transmitting hole is located, the current value corresponding to the scanning point is greater than 0, and if the scanning point is located outside the area where the light-transmitting hole is located, the current value corresponding to the scanning point is 0.

[0093] Furthermore, 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-transmitting hole and the center of the first scanning range of the actual scanning, 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 coincident with the optical axis, thereby realizing the emission axis alignment operation of the electron gun.

[0094] In addition, referring to the above description, during the operation of aligning the emission axis of the electron gun, the quality of the electron gun can also be detected based on the presence or absence of bright spots.

[0095] In summary, by adopting the pre-inspection method provided in the embodiment of the present invention, pre-inspection work such as alignment of the emission axis of the electron gun and quality inspection can be completed. After the pre-inspection is completed, the electron gun barrel can be installed as a whole in the scanning device. In this way, the disadvantages of on-site replacement of the cathode filament can be avoided (for example, avoiding the problems of complicated, time-consuming and difficult on-site alignment operations, avoiding a large amount of time wasted due to the installation of defective products, and avoiding 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, it is only necessary to fine-tune the on-site scanning electron microscope equipment, which can avoid searching for light spots in a large range, 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.

[0096] Based on the above embodiments, 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. Accordingly, the above-mentioned deflection of the electron beam 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 can include the following steps:

[0097] Step 1: 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;

[0098] Step 2: 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;

[0099] Step 3: 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;

[0100] Step 4: Determine the 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;

[0101] Step 5: Calculate the 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;

[0102] Step 6, calculating the 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 scanning step number;

[0103] Step seven, controlling the current change of the first deflection coil according to the first deflection current corresponding to each scanning point, and controlling the current change of the second deflection coil 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.

[0104] In step 1, 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, and the number of scanning points in each row can be determined according to the number of pixels in each row (the two are equal), and the number of scanning points in each column can be determined according to the number of pixels in each column (the two are equal), thereby determining the first scanning step number and the second scanning step number. Exemplarily, the pixel value of the grayscale image can be M*N, where M and N are both positive integers, M and N can be equal or unequal, M represents the number of pixels in each row of the grayscale image, and N represents the number of pixels in each column of the grayscale image. At this time, the first scanning step number can be M and the second scanning step number can be N.

[0106] In step 2, 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 electron beam is deflected to the maximum extent in the first direction; the second maximum current refers to the current on the second deflection coil when the electron beam is deflected to the maximum extent in the second direction.

[0107] The magnification represents the ratio between the size of the grayscale image and the size of the first scanning range. Referring to taking photos, for photos of the same size (same pixel value), the larger the magnification, the smaller the area actually photographed. Similarly, in this embodiment, for grayscale images of the same size, the larger the magnification, the smaller the area actually scanned (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 the current change required in the first direction and the second direction when scanning the first scanning range can be determined according to the current change required for the scanning unit size, respectively, and then the first maximum current and the second maximum current are determined. Exemplarily, assuming that the current change required to scan from one end of the first scanning range to the other end in the first direction is A, the first maximum current is X1=0.5A, assuming that the current change required to scan from one end of the first scanning range to the other end in the second direction is B, then the second maximum current Y1=0.5B.

[0108] Furthermore, in step 3, the first current range is determined to be -XI1 to +XI1 according to the first maximum current XI1, so that when the current of the first deflection coil is controlled to change within the range of -XI1 to +XI1, the electron beam can be scanned in the first direction with the position of the electron gun as the center. Similarly, in step 4, the second current range is determined to be -YI1 to +YI1 according to the second maximum current YI1, so that when the current of the second deflection coil is controlled to change within the range of -YI1 to +YI1, the electron beam can be scanned in the second direction with the position of the electron gun as the center, and the center of the first scanning range can be made to correspond to the position of the electron gun, which is convenient for subsequent alignment operations.

[0109] Further, step 5 and step 6 are performed, that is, according to the first current range and the first scanning step number, the first deflection current corresponding to each scanning point in the first direction of the first deflection coil is calculated, and according to the second current range and the second scanning step number, the second deflection current corresponding to each scanning point in the second direction of the second deflection coil is calculated. According to the above description, each scanning point corresponds to a first deflection current and a second deflection current, and different scanning 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 second deflection current corresponding to the scanning points in the same row is the same. When M scans are performed in the first direction so that each row has M scanning points, the current on 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, and 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, and thereafter, each step change of the first deflection current corresponds to a scanning point, and 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 thereafter, 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, that is, the current change of the first deflection coil is controlled according to the first deflection current corresponding to each scanning point, and at the same time, 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, Fig.10 Schematic diagram of a scanning principle provided by an embodiment of the present invention. Fig.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 the scanning from left to right 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 length. 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, which will not be described in detail. After determining the first deflection current and the second deflection current corresponding to each scanning point, the currents on the first deflection coil and the second deflection coil can be controlled to change accordingly, so that the electron beam can achieve single-point scanning line by line.

[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. Fig.11 is a schematic diagram of a first grayscale image obtained when the preset magnification value is a first magnification, such as Fig.11 As shown, the preset pixel value of the image is k*k, and the first current range corresponding to the first magnification is Fig.10 The second current range corresponding to -XI1~+XI1 is Fig.10 It can be understood that the size of the first current range and the second current range can be used to characterize the size of the actual scanning range. Fig.10 and Fig.11 It can be seen that when the scanning point is located in 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 ( Fig.11 Taking a circular bright spot as an example, the rest of the scanning positions are blocked by the aperture, so that the electron beam collection device cannot collect current and a dark area is formed in the grayscale image. Based on the above principle explanation, by adjusting the position of the electron gun so that the center of the bright spot coincides with the center of the image, the emission axis alignment operation of the electron gun can be completed, and the operation is simple and intuitive.

[0113] Reference Fig.11 , Optionally, in the grayscale image, the number of pixels in each row is equal to the number of pixels in each column. Exemplarily, Fig.11Taking the case where the number of pixels in each row and the number of pixels in each column are both k, that is, M=N=k, this configuration is helpful to simplify the calculation of the first deflection current and the second deflection current corresponding to each scanning point and improve the 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, so 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 yes, 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 first grayscale image generally refers to the grayscale image obtained at the first magnification. According to the above explanation, at the first magnification, if the position of the electron gun is adjusted, the first grayscale image will be updated, and the position of the bright spot in the updated first grayscale image will change, while the size of the bright spot remains unchanged (because the magnification remains unchanged), and of course, the center of the image remains unchanged (because the pixel value remains unchanged).

[0122] When the preset magnification value is the first magnification, specifically, when it is determined that there is a bright spot 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 to move the center of the bright spot toward the center of the image, and the emission axis alignment operation of the electron gun is performed; when it is determined that there is no bright spot in the first grayscale image, the position of the electron gun is adjusted, and the first grayscale image is updated. If there is a bright spot in the updated first grayscale image, the position of the electron gun is continued to be adjusted to move the center of the bright spot toward the center of the image, and the emission axis alignment operation of the electron gun is performed.

[0123] For example, refer to Fig.10 and Fig.11 Since the first magnification is relatively small, the scanning range corresponding to the first grayscale image obtained at the first magnification is relatively large (the first current range is -XI1 to +XI1, and the second current range is -YI1 to +YI1), and 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 also 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 Fig.11 Since the first magnification is relatively low, the size of the bright spot is relatively small. Therefore, if the center of the bright spot is made to coincide with the center of the grayscale image only in the first grayscale image obtained at the first magnification, it may be difficult to ensure that the two coincide accurately. To further ensure the alignment accuracy, this embodiment first obtains the first grayscale image at the first magnification, and performs a preliminary adjustment of the electron gun position according to the position of the bright spot in the first grayscale image, so that the center of the bright spot is close to the center of the image. Then, at a higher second magnification, a second grayscale image is obtained, and according to the position of the bright spot in the second grayscale image, the position of the electron gun is further adjusted to coincide with the center of the image, so as to improve the alignment accuracy of the emission axis.

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

[0126] According to 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 change on 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 under different magnifications is different. Exemplary, Fig.12 is a grayscale image obtained when the preset magnification value is the second magnification, and the corresponding first current range is, for example, Fig.10 The second current range of -XI2~+XI2 is Fig.10 The calculation method of -YI2~+YI2 in is as described above and will not be repeated here. Fig.11 and Fig.12 It can be seen that since the pixel value of the grayscale image remains unchanged, the first grayscale image (such as Fig.11 ) and the second grayscale image (such as Fig.12) is the same size, and the actual scanning area is made smaller by the magnification, so that the bright spot in the grayscale image can be magnified, which is convenient for further fine-tuning, so that the center of the bright spot coincides accurately with the center of the image, thereby improving the alignment accuracy of the emission axis.

[0127] Optionally, the pre-inspection method further includes: 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. Specifically, at a lower first magnification, if it is determined that there is no bright spot in the initial first grayscale image, and after adjusting the position of the electron gun and updating the first grayscale image, the bright spot still cannot be found in the image, then it is determined that the electron gun is faulty. According to the above description, since the first magnification is low and the scanning range is relatively large, even if the light-transmitting hole is not included in the scanning range, it is also beneficial to make the scanning range close to the light-transmitting hole, and find the bright spot in the grayscale image by fine-tuning the position of the electron gun. However, 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. In this way, the quality of the electron gun can be detected synchronously during the alignment of the emission axis of the electron gun, thereby improving the pre-inspection efficiency and avoiding a lot of time waste caused by the installation of defective products on site.

[0128] For example, Fig.13 FIG. 1 is a schematic diagram of a specific flow chart of a pre-inspection method provided by an embodiment of the present invention, and summarizes the execution process of the pre-inspection work such as the emission axis adjustment and quality inspection of the electron gun. Fig.13 As shown, during the pre-inspection process, a low-magnification image is first generated, and a bright spot is searched under the low-magnification image; if a 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 terminated; if a bright spot exists but is not centered, the position of the electron gun is first adjusted to bring the bright spot close to the center of the image, and then the image magnification is adjusted to generate a high-magnification image, and the position of the electron gun is adjusted under the high-magnification image until the bright spot is centered, and the alignment operation is terminated; if no bright spot is observed under the low-magnification image, the position of the electron gun is adjusted; if the bright spot can be observed under the low-magnification image after adjusting the position of the electron gun several times, the above operation is performed until the bright spot is centered, and the alignment operation is terminated; if the number of times the electron gun is adjusted is too large and exceeds the standard, and the bright spot still cannot be observed under the low-magnification image, it is determined that the electron gun is faulty, and the pre-inspection is terminated.

[0129] According to the above description, in Fig.13 In the process, whether adjusting the position of the electron gun or adjusting the image magnification, the grayscale image is updated in real time. Fig.14 This is a specific flow chart of generating a grayscale image in a pre-check process provided by an embodiment of the present invention, so as to understand the image update process. Fig.14As shown, the process is as follows: a. Read the user's pixel setting (the number of scanning steps can be determined according to the pixel setting); b. Read the user's magnification setting (the current variation range of each deflection coil can be determined according to the magnification setting); c. Perform deflection control (determine 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 scanning step and the current variation range, perform deflection control, and make the electron beam scan point by point); d. Current acquisition (that is, while deflecting the control, the electron beam collection device collects the current value of the electron beam passing through the aperture light-transmitting hole to determine the current value corresponding to each scanning point); e. Image generation (convert the current value into a grayscale value and display it on the pixel point at the corresponding position to generate a grayscale image). By cyclically executing the above b, c, d and e, the real-time update of the grayscale image is realized.

[0130] In some embodiments, the quality inspection of the electron gun may also be performed in the following manner. Optionally, the pre-inspection method further comprises: after the center of the bright spot coincides with the center of the image, receiving a first current value of the electron beam passing through the light-transmitting hole collected by the electron beam collecting 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] The specific values ​​of the standard current value and the preset threshold value can be set by yourself, and the embodiment of the present invention does not limit this. Generally, the current value of the electron beam that can pass through the light-transmitting hole has a reference standard value. If the difference between the actually collected first current value and the standard value is too large, for example, greater than the preset threshold value, it can be determined that the electron gun is defective.

[0132] It should be noted that the quality detection of the electron gun may adopt at least one of the above two methods, which is not limited in the embodiment of the present invention.

[0133] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pre-inspection system for an electron gun, characterized in that: include: Deflection tube, measuring 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 comprises 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 the 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 electron beam to deflect 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 and 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 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.

2. The pre-check 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-check 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 driving 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-check system according to claim 3, characterized in that: The pre-inspection system further comprises 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, implemented by 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 deflect 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 and 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 in the scanning process collected by the electron beam collecting 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 comprises a first deflection coil and a second deflection coil; the deflection lens barrel is used to control the electron beam to deflect in a first direction and a second direction so that the electron beam scans a first scanning range point by point, comprising: 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, and the second current range is -YI1 to +YI1; YI1 is a positive number; 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; calculating, according to the second current range and the second scanning step number, 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-checking 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 comprises: Setting the preset magnification value to a first magnification to obtain a first grayscale image; 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 yes, adjust 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; Wherein, 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 also includes: 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, and 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