Secondary electron detector, scanning electron beam imaging device and scanning electron beam imaging method

Abstract

The invention provides a secondary electron detector and a scanning electron beam imaging device and method, and relates to the technical field of scanning electron microscopes. The secondary electron detector comprises a detection device which comprises a plurality of detection areas, absorbs secondary electrons through the plurality of detection areas, and is also used for converting the secondary electrons into scintillation light and transmitting the scintillation light to a photoelectric conversion device; the photoelectric conversion device is coupled with the detection device and comprises a plurality of photoelectric conversion units, the photoelectric conversion units correspond to at least one detection area in the detection areas, and the photoelectric conversion units are used for converting the scintillation light corresponding to the at least one detection area into electric signals. Each electric signal can represent the number information and the emitting direction of the secondary electrons absorbed at the corresponding at least one detection area. The sample surface image is generated by utilizing a plurality of electric signals capable of representing more information, so that the authenticity of the generated sample surface image is improved.

Description

[0001] Cross-references

[0002] This application claims priority. The application number of the prior application is: 202410130943X. The name of the invention is: secondary electron detector, scanning electron beam imaging device, method. The priority date is January 30, 2024.

[0003] This application claims priority to Chinese Patent Application No. 202410130943X, filed on January 30, 2024, entitled “SECONDARY ELECTRON DETECTOR, SCANNING ELECTRON BEAM IMAGING DEVICE, AND METHOD”, which is expressly incorporated herein by reference in its entirety. Technical Field

[0004] The present disclosure relates to the technical field of scanning electron microscopes, and in particular to a secondary electron detector, a scanning electron beam imaging device, and a method. Background Art

[0005] In the field of scanning electron microscopy, a secondary electron detector is a tool for detecting secondary electrons emitted by a sample.

[0006] In the related technology, the secondary electron detector absorbs secondary electrons emitted from the sample surface through a thin scintillator surface, converts the secondary electrons into scintillation light, transmits the scintillation light to the photodetector through a light guide, and then converts the scintillation light into an electrical signal through the photodetector.

[0007] However, the electrical signal generated by the secondary electron detector in the related art can only represent the quantity information of the secondary electrons, and the authenticity of the sample surface image generated using the electrical signal is low.

[0008] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0009] The present disclosure provides a secondary electron detector, a scanning electron beam imaging device, and a method, which at least to a certain extent overcome the problem that the electrical signal generated by the secondary electron detector represents little information, and are conducive to improving the authenticity of the sample surface image.

[0010] According to one aspect of the present disclosure, a secondary electron detector is provided, comprising: a detection device, comprising a plurality of detection areas, the detection device absorbing secondary electrons through the plurality of detection areas, the detection device also being used to convert the secondary electrons into scintillation light, and transmitting the scintillation light to a photoelectric conversion device; a photoelectric conversion device, coupled to the detection device, comprising a plurality of photoelectric conversion units, the photoelectric conversion unit corresponding to at least one detection area among the plurality of detection areas, the photoelectric conversion unit being used to convert the scintillation light corresponding to the at least one detection area into an electrical signal.

[0011] In one embodiment of the present disclosure, the detection device further comprises a plurality of light pipes; each light pipe comprises a first end face and a second end face, the first end face is coupled to a detection region, and the second end face is coupled to a photoelectric conversion unit.

[0012] In one embodiment of the present disclosure, the detection device includes at least one scintillator, and the plurality of detection areas are respectively arranged on a surface of the at least one scintillator located on the same side.

[0013] In one embodiment of the present disclosure, the detection device includes a scintillation fiber array, the scintillation fiber array includes a plurality of scintillation fibers; the scintillation fiber includes a third end face and a fourth end face, the third end face of at least one scintillation fiber is a detection area, and the fourth end face is coupled to a photoelectric conversion unit.

[0014] In one embodiment of the present disclosure, the scintillating optical fiber is a scintillating glass optical fiber; or, the scintillating optical fiber is a scintillating plastic optical fiber; or, the scintillating optical fiber is a scintillating crystal optical fiber; or, the scintillating optical fiber is a microcrystalline glass optical fiber.

[0015] In one embodiment of the present disclosure, any two detection areas among the multiple detection areas are closely arranged or dispersedly arranged.

[0016] In one embodiment of the present disclosure, the detection surface formed by the multiple detection areas is a curved surface that is bent toward a side for receiving secondary electrons.

[0017] In one embodiment of the present disclosure, the plurality of detection areas are arranged in a preset shape, and an opening is left at a central position of the preset shape, and the opening is used for allowing an electron beam that excites secondary electrons to pass through.

[0018] In one embodiment of the present disclosure, the preset shape is a disc; or, the preset shape is an ellipse; or, the preset shape is a polygon.

[0019] In one embodiment of the present disclosure, the photoelectric conversion device is a multi-anode photomultiplier tube, and one photoelectric conversion unit corresponds to one anode in the multi-anode photomultiplier tube; or, the photoelectric conversion device is a silicon photomultiplier tube array, and the silicon photomultiplier tube array includes a plurality of silicon photomultiplier tube detection units, and the plurality of silicon photomultiplier tube detection units correspond one-to-one to the plurality of photoelectric conversion units; or, the photoelectric conversion device is a photodiode array, and the photodiode array includes a plurality of photodiodes, and the plurality of photodiodes correspond one-to-one to the plurality of photoelectric conversion units.

[0020] In one embodiment of the present disclosure, it further includes: an electrode device, located on a side of the detection surface formed by the multiple detection areas for receiving secondary electrons, for attracting secondary electrons.

[0021] According to another aspect of the present disclosure, a scanning electron beam imaging device is provided, wherein the scanning electron beam imaging device is applied with a secondary electron detector such as in any one of the above embodiments.

[0022] According to another aspect of the present disclosure, a scanning electron beam imaging method is provided, which is applied to the scanning electron beam imaging device as described in the above embodiment, including: absorbing secondary electrons emitted from the sample surface by the detection device, and converting the secondary electrons emitted from the sample surface into scintillation light; converting the scintillation light into multiple electrical signals by the photoelectric conversion device, one electrical signal corresponding to one photoelectric conversion unit; and generating an image of the sample surface according to the multiple electrical signals.

[0023] In one embodiment of the present disclosure, generating an image of the sample surface based on the multiple electrical signals includes: determining the number of pulses in each electrical signal; and generating an image of the sample surface based on the number of pulses of each electrical signal and / or the ratio between the number of pulses of each electrical signal.

[0024] In one embodiment of the present disclosure, an image of the sample surface is generated based on the number of pulses of each electrical signal and / or the ratio between the number of pulses of each electrical signal, including: determining a weight value of each electrical signal; and generating an image of the sample surface based on the product of the weight of each electrical signal and the number of pulses and / or the ratio between the number of pulses of each electrical signal.

[0025] The technical solution provided by the embodiments of the present disclosure includes at least the following beneficial effects:

[0026] In the technical solution provided by the embodiments of the present disclosure, the photoelectric conversion device includes a plurality of photoelectric conversion units, and each photoelectric conversion unit can convert the scintillation light generated at the corresponding at least one detection area into an electrical signal, thereby obtaining a plurality of electrical signals. In addition to representing the quantity information of the secondary electrons absorbed at the corresponding at least one detection area, each electrical signal can also represent the emission direction of the secondary electrons absorbed at the at least one detection area. Using a plurality of electrical signals that can represent more information to generate a sample surface image is conducive to improving the authenticity of the generated sample surface image.

[0027] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0029] Figure 1 This is a schematic diagram of the structure of a secondary electron detector in one embodiment of the present disclosure;

[0030] Figure 2 A schematic diagram of an arrangement structure of multiple detection areas in one embodiment of the present disclosure;

[0031] Figure 3 A schematic diagram of an arrangement structure of multiple detection areas in another embodiment of the present disclosure;

[0032] Figure 4 A schematic diagram of a plurality of detection areas being arranged on a scintillator in one embodiment of the present disclosure;

[0033] Figure 5 This is a schematic diagram of another embodiment of the present disclosure in which multiple detection areas are arranged on a scintillator;

[0034] Figure 6 A schematic diagram of a plurality of detection areas being arranged on two scintillators in one embodiment of the present disclosure;

[0035] Figure 7 It is a schematic structural diagram of a secondary electron detector in another embodiment of the present disclosure;

[0036] Figure 8 A schematic diagram of a scintillating optical fiber array according to an embodiment of the present disclosure;

[0037] Fig. 9A schematic diagram of the structure of a scintillation optical fiber in one embodiment of the present disclosure;

[0038] Fig.10 A schematic diagram of multiple detection areas and openings in one embodiment of the present disclosure;

[0039] Fig.11 This is a schematic structural diagram of a secondary electron detector in yet another embodiment of the present disclosure;

[0040] Fig.12 A schematic diagram of the structure of a scanning electron beam imaging device in one embodiment of the present disclosure;

[0041] Fig.13 A flowchart of a scanning electron beam imaging method according to an embodiment of the present disclosure;

[0042] Fig.14 It is a schematic diagram of stimulated emission of secondary electrons by a sample in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0043] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0044] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0045] It should be understood that the various steps described in the method embodiments of the present disclosure may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0046] It should be noted that the concepts such as “first” and “second” mentioned in the present disclosure are only used to distinguish different objects, and are not used to limit the interdependence of these objects.

[0047] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0048] like Figure 1 As shown, the secondary electron detector in the embodiment of the present disclosure may include: a detection device 11 and a photoelectric conversion device 12.

[0049] The detection device 11 includes a plurality of detection areas 111 , through which the detection device absorbs secondary electrons. The detection device can also convert the absorbed secondary electrons into scintillation light, and transmit the scintillation light to the photoelectric conversion device 12 .

[0050] The photoelectric conversion device 12 is coupled to the detection device 11, and the photoelectric conversion device 12 includes multiple photoelectric conversion units 121. One photoelectric conversion unit 121 corresponds to at least one detection area among the multiple detection areas 111. The photoelectric conversion unit 121 is used to convert the flash light corresponding to at least one detection area into an electrical signal.

[0051] It should be noted that Figure 1 The fact that each detection area 111 is rectangular is merely exemplary, and the shape of each detection area in the multiple detection areas 111 can be any shape, for example, a circle, an ellipse, a triangle, an irregular shape, etc., and the shapes of any two detection areas in the multiple detection areas 111 can be the same or different, and the embodiments of the present disclosure are not limited to this.

[0052] In addition, the areas of any two detection areas in the multiple detection areas 111 may be the same or different, and the embodiments of the present disclosure do not limit this.

[0053] It should also be noted that Figure 1 The rectangular arrangement of the multiple detection areas 111 of the detection device 11 is merely exemplary. The arrangement of the multiple detection areas 111 may also be in other shapes such as a circle or an ellipse, and the embodiments of the present disclosure are not limited thereto.

[0054] It should also be noted that Figure 1 The multiple detection areas 111 ( Figure 1 The close and seamless arrangement of the multiple detection areas 111 (eg, 9 detection areas) is only exemplary, and the multiple detection areas 111 may also be arranged in a dispersed manner, such as Figure 2 Alternatively, at least two of the plurality of detection areas 111 may be arranged in a dispersed manner, such as Figure 3 As shown, eight detection areas are closely arranged, and one detection area is dispersedly arranged with the eight detection areas.

[0055] The embodiments of the present disclosure do not limit the number of the multiple detection areas. For example, the multiple detection areas 111 may be as follows: Figure 1 There are 9 detection areas shown in FIG. 1 ; for another example, the plurality of detection areas 111 may be 100 detection areas, or 500 detection areas, or 1000 detection areas, and so on.

[0056] In one embodiment, Figure 4 As shown, the detection device 11 may include at least one scintillator 112 , and the plurality of detection regions 111 are respectively arranged on a surface 41 on the same side as the at least one scintillator 112 .

[0057] Figure 4 In the figure, at least one scintillator 112 is drawn as one scintillator, and 12 detection areas are set on the scintillator. Figure 4 The plurality of detection regions 111 (12 detection regions) do not cover the entire surface of one side of the scintillator 112 and are merely exemplary. Figure 5 As shown, the multiple detection areas 111 can also completely cover the surface of one side of the scintillator 112 .

[0058] Figure 6 In the figure, at least one scintillator 112 is two scintillators, and four detection areas are set on each scintillator. The detection areas 111 can be set closely and seamlessly on the surface of the scintillator, or can be set dispersedly, and the embodiments of the present disclosure do not limit this.

[0059] The embodiment of the present disclosure does not limit the specific number of the at least one scintillator. For example, the at least one scintillator may be 2 scintillators, or 3, 4, 5 scintillators, etc. Each scintillator is provided with at least one detection area.

[0060] The embodiments of the present disclosure do not limit the specific material used for the at least one scintillator. For example, the material may include but is not limited to any one or more of the following scintillators: lanthanum bromide LaBr3 (Ce), sodium iodide NaI (Tl, Li) and other halides doped with other ions, bismuth germanate Bi4Ge3O 12 And oxides such as cadmium tungstate CdWO4, and fluorides such as barium fluoride BaF2.

[0061] In the case where the detection device 11 includes at least one scintillator, the photoelectric conversion device 12 is coupled to the detection device 11, which means that at least one scintillator is directly coupled to the photoelectric conversion device 12. The embodiments of the present disclosure do not limit the implementation method of the coupling. For example, a material with light-conducting and adhesive properties (for example, silicone oil, optical glue, etc.) can be used to achieve the direct coupling of at least one scintillator and the photoelectric conversion device 12, and the coupling of the two can also be achieved by mechanically fixing at least one scintillator and the photoelectric conversion device 12.

[0062] In another embodiment, Figure 7 As shown, the detection device 11 includes at least one scintillator 112 and a plurality of light guides 113 .

[0063] The surface 41 is a surface on one side of the scintillator where a plurality of detection regions 111 are arranged, and the region 71 is a region corresponding to the detection region on the other side opposite to the surface 41 .

[0064] Each light pipe 113 includes a first end surface and a second end surface, wherein the first end surface is coupled to one detection region 111 , and the second end surface is coupled to one photoelectric conversion unit 121 .

[0065] In one embodiment, coupling the first end face with a detection area 111 may include: the first end face is optically connected to a corresponding area on the other side of the detection area 111 opposite to the surface 41 (a connection method that allows light transmission), so that after the detection area 111 absorbs secondary electrons, the scintillator absorbs the secondary electrons and emits scintillation light. The scintillation light can be emitted from the area on the other side of the detection area opposite to the surface 41. The scintillation light can enter the optical fiber 113 optically connected to the area, and be transmitted to the photoelectric conversion device 12 via the optical fiber 113. The scintillation light can be specifically transmitted to the photoelectric conversion unit 121 on the photoelectric conversion device 12 that is coupled to the optical fiber 113.

[0066] In one embodiment, one detection area 111 can be coupled to at least one first end surface, that is, one detection area 111 can be coupled to at least one light pipe, so that the scintillation light emitted by the detection area 111 can be fully transmitted to the same photoelectric conversion unit 121. It should be noted that the second end surface of the at least one light pipe is coupled to the same photoelectric conversion unit.

[0067] In one embodiment, one photoelectric conversion unit 121 may be coupled to all light pipes coupled to at least one detection region 111 , wherein the at least one detection region 111 is a detection region corresponding to the photoelectric conversion unit 121 in the plurality of detection regions 111 .

[0068] In one embodiment, the first end surface of at least one light pipe 113 coupled to one detection area 111 may cover a corresponding area of ​​the detection area 111 on the other side opposite to the surface 41 .

[0069] In another embodiment, the size and position of the detection area 111 are determined by the area and position covered by the first end surface of at least one light pipe 113 coupled to the detection area 111 .

[0070] In one embodiment, the shapes of the first end surfaces of different light guides may be the same or different. The shape of the first end surface of a light guide may be circular, elliptical, polygonal, irregular, etc.

[0071] In one embodiment, the areas of the first end surfaces of different light pipes may be the same or different, and the embodiments of the present disclosure are not limited to this.

[0072] In one embodiment, each detection area 111 is coupled to a light pipe 113, and the first end surfaces of different light pipes have the same area. The first end surfaces of the different light pipes 113 having the same area include: the first end surfaces of the different light pipes 113 have the same shape and size, and the first end surfaces of the different light pipes 113 have different shapes and the same area.

[0073] In yet another embodiment, Figure 8 As shown, the detection device 11 includes a scintillation fiber array 114 , and the scintillation fiber array includes a plurality of scintillation fibers 1141 .

[0074] A scintillation optical fiber 1141 includes a third end face and a fourth end face. The third end face of at least one scintillation optical fiber 1141 is a detection area, and the fourth end face is coupled to a photoelectric conversion unit 121 .

[0075] The scintillation fiber includes a core and a cladding, and the constituent material of the core includes a scintillator. Therefore, after the secondary electrons are injected into the third end face of the scintillation fiber, they can be absorbed by the scintillator in the core and generate scintillation light, and the scintillation light can also be transmitted by the scintillation fiber.

[0076] One photoelectric conversion unit 121 corresponds to at least one detection region 111 . Accordingly, one photoelectric conversion unit 121 can be coupled to the fourth end faces of all scintillation optical fibers 1141 corresponding to at least one detection region 111 .

[0077] It should be noted that the number of the third end faces of at least one scintillation optical fiber constituting different detection areas may be the same or different. The embodiments of the present disclosure do not limit this. For example, one detection area is composed of the third end faces of three scintillation optical fibers, and another detection area is composed of the third end faces of four scintillation optical fibers.

[0078] It should be noted that the shapes of the third end faces of different scintillation fibers in the plurality of scintillation fibers 1141 may be the same or different. The shape of the first end face of the scintillation fiber may be circular, elliptical, polygonal or irregular, which is not limited in the embodiments of the present disclosure. In addition, the areas of the third end faces of different scintillation fibers may be the same or different.

[0079] In one embodiment, each of the plurality of detection regions 111 is a third end surface, and the third end surfaces of different scintillation optical fibers 1141 have the same shape and size.

[0080] In one embodiment, different photoelectric conversion units 121 among the multiple photoelectric conversion units 121 correspond to the same number of at least one detection area 111, that is, different photoelectric conversion units 121 correspond to the same number of detection areas 111. Then, when each detection area 111 among the multiple detection areas 111 has the same number of third end faces, different photoelectric conversion units are coupled with the same number of fourth end faces of the scintillation optical fiber 1141.

[0081] For example, if one photoelectric conversion unit 121 corresponds to at least one detection area 111 which is 3, and each detection area 111 in the plurality of detection areas is a third end face, then one photoelectric conversion unit 121 is coupled to the fourth end faces of three scintillating optical fibers 1141 .

[0082] In one embodiment, the third end face of a scintillation fiber 1141 is a detection area 111 , and at least one detection area 111 corresponding to a photoelectric conversion unit 121 is a detection area 111 , then a photoelectric conversion unit 121 is coupled to the fourth end face of a scintillation fiber 1141 .

[0083] The embodiments of the present disclosure do not limit the specific implementation of coupling the fourth end face of the scintillation fiber 1141 with the photoelectric conversion unit 121. In one embodiment, the coupling of the fourth end face of the scintillation fiber 1141 with the photoelectric conversion unit 121 can be achieved by a material with light-guiding and adhesive properties (e.g., silicone oil, optical glue, etc.), or by mechanical fixing.

[0084] In one embodiment, the scintillating optical fiber may be a scintillating glass optical fiber; or, the scintillating optical fiber may be a scintillating plastic optical fiber; or, the scintillating optical fiber may be a scintillating crystal optical fiber; or, the scintillating optical fiber may be a microcrystalline glass optical fiber.

[0085] In one embodiment, Fig. 9As shown, the core of each scintillation optical fiber 1141 includes a first core section 1142 and a second core section 1143, and the core within a preset length from the third end face of the scintillation optical fiber 1141 is the first core section 1142, and the constituent material of the first core section 1142 includes a scintillator, and the constituent material of the second core section 1143 is a preset material, and the difference in refractive index between the preset material and the scintillator is less than a preset value.

[0086] The embodiments of the present disclosure do not limit what the predetermined material is, and the predetermined material can be determined according to the refractive index of the specific scintillator constituting the first section of the fiber core 1142, thereby ensuring that the difference in refractive index between the predetermined material and the scintillator is less than a preset value. The embodiments of the present disclosure do not limit what the predetermined value is, for example, the predetermined value is 0.1 or 0.2.

[0087] The method of using scintillators to form the first section of the fiber core 1142 within a preset length from the third end face can reduce the use of scintillators and reduce the cost of manufacturing scintillating optical fibers. The difference in refractive index between the scintillators participating in forming the first section of the fiber core 1142 and the predetermined material forming the second section of the fiber core 1143 is less than a preset value, so that the light loss when the light enters the second section of the fiber core 1143 from the first section of the fiber core 1142 can be controlled within a smaller range.

[0088] In one embodiment, the photoelectric conversion device can be any photodetector array.

[0089] In one embodiment, the photoelectric conversion device is a multi-anode photomultiplier tube, and one photoelectric conversion unit corresponds to one anode in the multi-anode photomultiplier tube; or, the photoelectric conversion device is a silicon photomultiplier tube array, and the silicon photomultiplier tube array includes multiple silicon photomultiplier tube detection units, and the multiple silicon photomultiplier tube detection units correspond one-to-one to the multiple photoelectric conversion units; or, the photoelectric conversion device is a photodiode array, and the photodiode array includes multiple photodiodes, and the multiple photodiodes correspond one-to-one to the multiple photoelectric conversion units; or, the photoelectric conversion device is an avalanche photodiode array, and the avalanche photodiode array includes multiple avalanche photodiodes, and the multiple avalanche photodiodes correspond one-to-one to the multiple photoelectric conversion units.

[0090] Among them, each anode in the multi-anode photomultiplier tube has a time resolution of <30ps (picoseconds), and the anode signal output is a pulse waveform, the rise time of the pulse is within 300ps, and the width of the pulse waveform is usually less than 500ps. The ultra-narrow pulse signal can avoid the overlap of pulse signals, which is conducive to improving the accuracy of the secondary electron detector when counting. In addition, the ultra-fast time resolution can improve the detection efficiency of the scanning electron microscope using the secondary electron detector.

[0091] In one embodiment, the secondary electron detector includes, in addition to the detection device 11 and the photoelectric conversion device 12, an electrode device, which is located on a side of the detection surface formed by the multiple detection regions 111 for receiving secondary electrons, and is used to attract secondary electrons.

[0092] In one embodiment, the electrode device may be a grid electrode or an electrode film layer.

[0093] In one embodiment, any two detection areas 111 among the plurality of detection areas 111 are closely arranged or dispersedly arranged.

[0094] In one embodiment, the detection surface formed by the multiple detection areas 111 is a curved surface that is bent toward the side for receiving secondary electrons, thereby increasing the detection area without increasing the use of scintillators or scintillating fibers, so as to receive more secondary electrons and improve the sensitivity of the secondary electron detector.

[0095] In one embodiment, Fig.10 As shown, the arrangement of multiple detection areas 111 is in a preset shape, and an opening 101 is left at the center of the preset shape, and the opening 101 is used for the electron beam that excites the secondary electrons to pass through. By leaving the opening 101 at the center of the preset shape, the secondary electron detector can be directly set on the sample to detect the secondary electrons emitted by the sample.

[0096] It should be noted that Fig.10 The preset shape is drawn as a disc, but it is not used to limit the preset shape to only a disc. In one embodiment, the preset shape can be a disc; or, the preset shape can be an ellipse; or, the preset shape can be a polygon; or, the preset shape is an irregular shape.

[0097] It should also be noted that there may be no openings in the preset shape formed by the multiple detection areas 111, and the secondary electron detector may not be set on the path of the electron beam emitted to the sample, but may be set at other positions that can absorb the secondary electrons generated by the sample being excited by the electron beam. In addition, the secondary electron detector can attract secondary electrons through the electric field generated by the electrode device.

[0098] To facilitate understanding of the implementation principles of various secondary electron detectors provided in the embodiments of the present disclosure, Fig.10 and Fig.11 to explain.

[0099] in, Fig.10 A detection area 111 may be a third end face of a scintillation optical fiber 1141 . Fig.11In the embodiment, the electrode film layer 13 is used to attract secondary electrons. After the electrode film layer 13 attracts the secondary electrons, the attracted secondary electrons enter each detection area (the third end face of the scintillation optical fiber 114). The scintillator in the core of the scintillation optical fiber 1141 absorbs the secondary electrons to generate scintillation light. The scintillation light is transmitted through the scintillation optical fiber 1141 into the photoelectric conversion device 12 (taking the photoelectric conversion device 12 as a multi-anode photomultiplier tube as an example, the photoelectric conversion unit 121 corresponds to one anode). Among them, one photoelectric conversion unit 121 can be coupled with the fourth end face of at least one scintillation optical fiber 1141 (for example, at least one scintillation optical fiber 114 is an adjacent scintillation optical fiber in arrangement), so that the scintillation light transmitted by at least one scintillation optical fiber 1141 is processed by the photoelectric conversion unit 121 and converted into an electrical signal. If one photoelectric conversion unit 121 generates one electrical signal, then multiple photoelectric conversion units 121 generate multiple electrical signals.

[0100] Since the detection areas are arranged at different positions, the secondary electrons absorbed by different detection areas have different emission directions, so each electrical signal can represent the emission direction information and quantity information of the secondary electrons.

[0101] Furthermore, using multiple electrical signals that can represent more information (emission direction information and quantity information of secondary electrons) to generate a sample surface image is beneficial to improving the authenticity of the generated sample surface image.

[0102] In one embodiment, the present disclosure further provides a scanning electron beam imaging device, which is applied with a secondary electron detector such as in any one of the above embodiments.

[0103] In one embodiment, Fig.12 As shown, the scanning electron beam imaging device may include: an electron gun 1201 , a lens system 1202 , a sample stage 1203 , a secondary electron detector 1204 , and an image processing system 1205 .

[0104] Among them, the electron gun 1201 is the electron emission source of the scanning electron beam imaging device, which is used to generate and accelerate the electron beam. The lens system 1202 is used to control and focus the electron beam, for example, to adjust the size, shape and focusing distance of the electron beam. The sample stage 1203 is used to place the sample to be observed. In one embodiment, the sample stage 1203 has the function of three-dimensional movement. The secondary electron detector 1204 is used to absorb the secondary electrons emitted from the sample surface through the detection device 12, and convert the secondary electrons emitted from the sample surface into scintillation light; the scintillation light is converted into multiple electrical signals through the photoelectric conversion device 12, and one electrical signal corresponds to one photoelectric conversion unit 121. The image processing system 1205 can generate a graphic of the sample surface based on the multiple electrical signals.

[0105] It should be noted that Fig.12 The relative position of the secondary electron detector 1204 and the sample stage 1203 is merely exemplary. In some embodiments, the secondary electron detector 1204 may also be disposed obliquely above the sample stage 1203, or at other locations where the secondary electrons emitted by the sample on the sample stage 1203 can be received.

[0106] In one embodiment, the present disclosure further provides a scanning electron beam imaging method, which is applied to the scanning electron beam imaging device in the above embodiment.

[0107] like Fig.13 As shown, the scanning electron beam imaging method includes the following S1301 to S1303.

[0108] S1301, absorbing secondary electrons emitted from the sample surface through a detection device, and converting the secondary electrons emitted from the sample surface into scintillation light.

[0109] Among them, the specific implementation of S1301 can refer to the various embodiments of the secondary electron detector and the embodiments of the scanning electron beam imaging device mentioned above, and will not be repeated here.

[0110] S1302, converting the flashing light into a plurality of electrical signals through a photoelectric conversion device, where one electrical signal corresponds to one photoelectric conversion unit.

[0111] Among them, the specific implementation of S1302 can refer to the various embodiments of the secondary electron detector and the embodiments of the scanning electron beam imaging device mentioned above, which will not be repeated here.

[0112] S1303, generating an image of the sample surface according to the multiple electrical signals.

[0113] In one embodiment, generating an image of the sample surface according to the multiple electrical signals may be directly generating the image of the sample surface according to the total number of pulses in the multiple electrical signals.

[0114] After the sample is excited by the electron beam, the emission direction and quantity of the secondary electrons are affected by the specific morphology of the sample surface. The morphology of the sample surface usually includes convexities, concavities, planes, etc. Fig.14 As shown, after being excited by the electron beam, compared with the plane, among the secondary electrons emitted by the protrusion 1401, more secondary electrons with a large exit angle can be emitted from the sample due to the shorter exit path, thereby making the proportion of secondary electrons with a large angle among the secondary electrons emitted by the protrusion 1401 higher than that of the plane.

[0115] For concave morphology, the distance that secondary electrons need to travel in the sample when emitting is greater. Therefore, for concave morphology, relatively few secondary electrons are emitted through the sample in each direction, and even if the angle between the emission angle of the secondary electrons and the vertical plane direction is small, they still need to travel a longer distance in the sample (compared with the case of a plane).

[0116] It can be seen that after being excited by the electron beam, different surface morphologies of samples have different ratios of secondary electrons emitted through the sample in various directions. Among them, the total number of secondary electrons emitted through the sample at the protrusion is large, and the proportion of secondary electrons emitted at large angles is large (compared with the plane); the total number of secondary electrons emitted at the depression is small, and the proportion of secondary electrons emitted at large angles is small (compared with the plane). Therefore, the morphology of the sample surface can also be determined by the ratio of the number of secondary electrons in different directions. The secondary electron detector in each embodiment of the present disclosure can detect the number of secondary electrons emitted by the sample in different directions.

[0117] In one embodiment, generating an image of the sample surface based on multiple electrical signals may include: determining the number of pulses in each electrical signal; and generating an image of the sample surface based on the number of pulses of each electrical signal and / or the ratio between the number of pulses of each electrical signal.

[0118] In addition, the protrusions and edges of the sample surface usually form local high brightness and high contrast features on the sample surface image formed based on the secondary electrons because the number of emitted secondary electrons is larger than that of the flat surface. In some cases, it may also cause local images or brightness distortion that cannot truly reflect the intrinsic morphology of the sample surface.

[0119] This problem can be solved by reducing the weight of the electrical signal generated by secondary electrons with a larger exit angle when generating an image of the sample surface.

[0120] In one embodiment, generating an image of the sample surface based on the number of pulses of each electrical signal and / or the ratio between the number of pulses of each electrical signal may include: determining a weight value for each electrical signal; generating an image of the sample surface based on the product of the weight of each electrical signal and the number of pulses and / or the ratio between the number of pulses of each electrical signal.

[0121] In one case, when a sample is made of different materials, the number of stimulated secondary electrons emitted from surfaces with the same morphology may be different. In this case, the image of the sample surface generated by the total count of secondary electrons is not accurate enough. However, by using the ratio between the number of pulses of each electrical signal, the total count of secondary electrons can be ignored, and only the ratio between the counts of secondary electrons in each direction can be considered, so that the image of the sample surface can be correctly generated.

[0122] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A secondary electron detector, characterized in that: include: A detection device, comprising a plurality of detection regions, wherein the detection device absorbs secondary electrons through the plurality of detection regions, and the detection device is further used to convert the secondary electrons into scintillation light, and transmit the scintillation light to the photoelectric conversion device; The photoelectric conversion device is coupled to the detection device and includes a plurality of photoelectric conversion units, each of which corresponds to at least one detection area among the plurality of detection areas and is used to convert the scintillation light corresponding to the at least one detection area into an electrical signal.

2. The secondary electron detector according to claim 1, characterized in that: The detection device includes at least one scintillator, and the plurality of detection areas are respectively arranged on a surface of the at least one scintillator located on the same side.

3. The secondary electron detector according to claim 2, characterized in that: The detection device also includes a plurality of light guide tubes; Each optical waveguide comprises a first end surface and a second end surface, wherein the first end surface is coupled to a detection region, and the second end surface is coupled to a photoelectric conversion unit.

4. The secondary electron detector according to claim 1, characterized in that: The detection device comprises a scintillation optical fiber array, wherein the scintillation optical fiber array comprises a plurality of scintillation optical fibers; The scintillation optical fiber comprises a third end face and a fourth end face. The third end face of at least one scintillation optical fiber is a detection area, and the fourth end face is coupled to a photoelectric conversion unit.

5. The secondary electron detector according to claim 4, characterized in that: The scintillating optical fiber is a scintillating glass optical fiber; or, the scintillating optical fiber is a scintillating plastic optical fiber; or, the scintillating optical fiber is a scintillating crystal optical fiber; or, the scintillating optical fiber is a microcrystalline glass optical fiber.

6. The secondary electron detector according to claim 4, characterized in that: Any two detection areas among the multiple detection areas are closely arranged or dispersedly arranged.

7. The secondary electron detector according to any one of claims 1 to 6, characterized in that: The detection surface formed by the multiple detection areas is a curved surface that is bent toward a side for receiving secondary electrons.

8. The secondary electron detector according to any one of claims 1 to 6, characterized in that: The plurality of detection areas are arranged in a preset shape, and an opening is left at a central position of the preset shape, and the opening is used for allowing an electron beam that excites secondary electrons to pass through.

9. The secondary electron detector according to claim 8, characterized in that: The preset shape is a disc; or, the preset shape is an ellipse; or, the preset shape is a polygon.

10. The secondary electron detector according to claim 1, characterized in that: The photoelectric conversion device is a multi-anode photomultiplier tube, and one photoelectric conversion unit corresponds to one anode in the multi-anode photomultiplier tube; Alternatively, the photoelectric conversion device is a silicon photomultiplier tube array, the silicon photomultiplier tube array includes a plurality of silicon photomultiplier tube detection units, and the plurality of silicon photomultiplier tube detection units correspond one to one to the plurality of photoelectric conversion units; Alternatively, the photoelectric conversion device is a photodiode array, the photodiode array includes a plurality of photodiodes, and the plurality of photodiodes correspond one-to-one to the plurality of photoelectric conversion units.

11. The secondary electron detector according to any one of claims 1 to 6 and 10, characterized in that: Also includes: The electrode device is located on a side of the detection surface formed by the multiple detection areas for receiving secondary electrons, and is used to attract secondary electrons.

12. The secondary electron detector according to claim 11, characterized in that: The electrode device is a grid electrode or an electrode film layer.

13. A scanning electron beam imaging device, characterized in that: The scanning electron beam imaging device is applied with a secondary electron detector such as that described in any one of claims 1-12.

14. A scanning electron beam imaging method, characterized in that: The scanning electron beam imaging device as claimed in claim 13 comprises: The detection device absorbs secondary electrons emitted from the sample surface and converts the secondary electrons emitted from the sample surface into scintillation light; The flashing light is converted into a plurality of electrical signals by the photoelectric conversion device, wherein one electrical signal corresponds to one photoelectric conversion unit; An image of the sample surface is generated based on the plurality of electrical signals.

15. The method according to claim 14, characterized in that Generating an image of the sample surface according to the plurality of electrical signals comprises: determining the number of pulses in each electrical signal; An image of the sample surface is generated according to the pulse numbers of the respective electrical signals and / or the ratio between the pulse numbers of the respective electrical signals.

16. The method according to claim 15, characterized in that Generating an image of the sample surface according to the number of pulses of each electrical signal and / or the ratio between the number of pulses of each electrical signal, comprising: Determining a weight value of each electrical signal; An image of the sample surface is generated according to the product of the weight of each electrical signal and the number of pulses and / or the ratio between the numbers of pulses of the electrical signals.

Images