Scanning system and electron beam control method

Abstract

The invention relates to the technical field of electron beam scanning, in particular to a scanning system and an electron beam control method.The scanning system comprises an integrated electromagnetic lens structure, the integrated electromagnetic lens structure comprises a main body part and an annular pole shoe part which are spaced, the annular pole shoe part and the main body part are electrically insulated, and magnetic circuits of the annular pole shoe part and the main body part are continuous; the annular pole shoe part comprises a plurality of deflection groups, the deflection groups are electrically insulated, and magnetic circuits are continuous; the voltage loaded on the main body part is different from the voltage loaded on the annular pole shoe, the voltages loaded on the deflection groups are different, the main body part is loaded with the corresponding voltage, and when the deflection groups are loaded with the corresponding voltage, the integrated electromagnetic lens structure realizes focusing and deflection of electron beams at the same time. The invention at least facilitates the reduction of the assembly complexity of the scanning system and the reduction of the size of the scanning system.

Description

Technical Field

[0001] The present invention belongs to the technical field of electron beam scanning, and in particular relates to a scanning system and an electron beam control method. Background Art

[0002] A scanning electron microscope (SEM) is a high-end electron optical instrument that uses a focused, high-energy incident electron beam to scan and bombard a sample. The interaction between the incident electron beam and the material stimulates various physical information, which is then collected, amplified, and re-imaged to characterize the microscopic morphology of the material. The core component of a SEM is the electromagnetic lens system, which primarily consists of an axisymmetric electromagnetic lens (such as a magnetic condenser or magnetic objective lens) for electron beam focusing and a multi-stage electric / magnetic lens (such as a quadrupole lens or an octopole lens) for electron beam deflection. The axisymmetric electromagnetic lens forms an axisymmetric magnetic field through a toroidal coil and a magnetic pole shoe to focus the electron beam. The multi-stage electric / magnetic lens deflects or scans the electron beam through the asymmetric field distribution of multiple sets of electrodes or magnetic poles.

[0003] Current electromagnetic lens systems have the following problems. On the one hand, they occupy a large space. Specifically, the independent focusing lenses and deflection lenses need to be stacked in multiple layers, which limits the miniaturization design of the electromagnetic lens system. On the other hand, the assembly complexity of the electromagnetic lens system is relatively high. The reason is that the multi-stage lenses need to be precisely aligned, otherwise the electron beam trajectory will be offset or aberrations will be generated. Therefore, the assembly complexity is relatively high. On the other hand, there is a signal interference problem. Specifically, the electromagnetic field of the multi-stage lenses used for deflection may interfere with the main focusing magnetic field and reduce the resolution.

[0004] In summary, traditional electromagnetic lens systems have problems such as large equipment size, complex assembly, and the introduction of multi-stage lenses that may interfere with the distribution of the main magnetic field and thus affect the resolution. Summary of the Invention

[0005] In view of this, the present invention aims to provide a scanning system and an electron beam control method, which are at least conducive to reducing the assembly complexity of the scanning system and reducing the volume of the scanning system.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: On the one hand, the present invention provides a scanning system, including: an integrated electromagnetic lens structure, the integrated electromagnetic lens structure includes a main body and an annular pole shoe portion spaced apart from each other, the annular pole shoe portion is electrically insulated from the main body and the magnetic circuit is continuous; the annular pole shoe portion includes multiple deflection groups, the deflection groups are electrically insulated from each other and the magnetic circuit is continuous; the voltage loaded on the main body is different from the voltage loaded on the annular pole shoe, and the voltage loaded on each deflection group is different. When the main body is loaded with corresponding voltages and the deflection groups are loaded with corresponding voltages, the integrated electromagnetic lens structure simultaneously realizes focusing and deflection of the electron beam.

[0007] Furthermore, when the deflection group is loaded with a corresponding voltage, the annular pole shoe portion forms a quadrupole deflection field, and the electron beam is deflected under the action of the quadrupole deflection field.

[0008] Furthermore, the annular pole shoe portion includes four deflection groups, which are the first deflection group, the second deflection group, the third deflection group and the fourth deflection group arranged in sequence, wherein the first deflection group and the third deflection group are symmetrical, and the second deflection group and the fourth deflection group are symmetrical; the voltage of each deflection group is adjustable, the voltage loaded by the first deflection group is the positive second voltage, the voltage loaded by the third deflection group is the negative second voltage, the voltage loaded by the second deflection group is the positive third voltage, and the voltage loaded by the fourth deflection group is the negative third voltage, and the second voltage and the third voltage are different.

[0009] Furthermore, each deflection group includes a sub-deflection unit; or, each deflection group includes N spaced sub-deflection units, where N is an integer greater than 1, and the sub-deflection units are electrically insulated and have continuous magnetic circuits.

[0010] Furthermore, each sub-deflecting portion is connected via a first sub-connecting portion to form an annular pole shoe portion, and the first sub-connecting portion is made of insulating material.

[0011] Furthermore, the integrated electromagnetic lens structure also includes an insulating connection portion, through which the annular pole shoe portion is connected to the main body portion, and the distance between the annular pole shoe portion and the main body portion is not less than a first preset distance.

[0012] Furthermore, the insulating connection part is made of non-magnetic insulating material, and the distance between the annular pole shoe part and the main body part is not greater than the second preset distance; or, the insulating connection part is made of magnetic insulating material, and the distance between the annular pole shoe part and the main body part is not greater than the third preset distance.

[0013] Furthermore, the scanning system also includes a condenser, which is located on the side of the integrated electromagnetic lens structure away from the sample, and is used to achieve preliminary convergence of the electron beam; the integrated electromagnetic lens structure serves as an objective lens, and the electron beam after preliminary convergence is focused on the sample through the objective lens.

[0014] Furthermore, the scanning system also includes a first deflection member, which is arranged in the electron beam channel of the integrated electromagnetic lens structure, and the first deflection member is located on a side of the annular pole shoe portion away from the sample.

[0015] Furthermore, the scanning system also includes a control component, which is used to regulate the voltage loaded onto the annular pole shoe portion and to regulate the voltage loaded onto the first deflection element.

[0016] Another aspect of the present invention provides an electron beam control method, comprising: providing the above-mentioned scanning system, the scanning system including an integrated electromagnetic lens structure, the integrated electromagnetic lens structure including a main body and an annular pole shoe portion, the annular pole shoe portion including multiple deflection groups; the electron beam control method comprising: regulating the main body and the annular pole shoe portion to load different voltages, and regulating each deflection group to load a different voltage, so that the integrated electromagnetic lens structure can simultaneously achieve focusing and deflection of the electron beam.

[0017] Furthermore, regulating the main body and the annular pole piece to load different voltages, and regulating each deflection group to load different voltages includes regulating the main body to be at a first voltage, and regulating the voltage of each deflection group within a preset range to achieve deflection fields of different intensities.

[0018] Furthermore, regulating the voltage of each deflection group within a preset range includes regulating each deflection group to apply a voltage on top of the first voltage.

[0019] Furthermore, the scanning system also includes a first deflection element and a control component; the electron beam control method also includes: using the control component to regulate the voltage of the loaded annular pole shoe portion to achieve a primary deflection of the electron beam, and achieving deflection scanning of the first field of view through a single deflection; or, using the control component to regulate the voltage of the loaded first deflection element to achieve a primary deflection of the electron beam, and regulating the voltage of the loaded annular pole shoe portion to achieve a secondary deflection of the electron beam, and achieving deflection scanning of the second field of view through two deflections; wherein the first field of view range is smaller than the second field of view range.

[0020] Compared with the prior art, the invention can achieve the following beneficial effects: the invention divides the axisymmetric magnetic pole shoe of the magnetic lens serving as the objective lens into a main body and an annular pole shoe, divides the annular pole shoe into a plurality of deflection groups, and designs that the main body and the annular pole shoe are electrically insulated but the magnetic circuit is continuous, and the deflection groups are also electrically insulated from each other and the magnetic circuit is continuous, applies a voltage different from that of the main body to the annular pole shoe, and applies a different voltage to each deflection group in the annular pole shoe, utilizes the annular pole shoe to form a deflection electric field, and changes the intensity of the deflection electric field by controlling the voltage loaded on the deflection group to realize deflection scanning of the electron beam, and the shape of the integrated electromagnetic lens structure formed by the main body and the annular pole shoe is exactly the same as that of the magnetic lens used to form the focusing magnetic field before division. , and the magnetic circuits of the main body and the annular pole shoe are continuous. Therefore, the integrated electromagnetic lens structure formed by the main body and the annular pole shoe can form a magnetic field for focusing the electron beam while forming a deflection electric field. That is, one component can be used to simultaneously realize the focusing and deflection scanning of the electron beam, and the volume and shape of the integrated electromagnetic lens structure for realizing the focusing and deflection scanning of the electron beam are the same as the volume and shape of the original objective lens used only for realizing focusing. Therefore, it is beneficial to reduce the occupied space of the lens while ensuring the realization of the focusing and deflection scanning of the electron beam, and avoids the assembly of multiple components, significantly reduces the complexity of assembly, and avoids the electromagnetic field of the multi-stage lens interfering with the main focusing magnetic field, alleviates the signal interference problem, and is beneficial to improving the resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 A schematic cross-sectional view of the integrated electromagnetic lens structure at its central axis according to an embodiment of the present invention; Figure 2 A schematic diagram of the three-dimensional structure of the integrated electromagnetic lens structure according to an embodiment of the present invention; Figure 3 A schematic structural diagram of an annular pole shoe portion according to an embodiment of the present invention is provided; Figure 4 A schematic diagram of the integrated electromagnetic lens structure forming a focusing magnetic field according to an embodiment of the present invention; Figure 5 A schematic diagram of a deflection electric field formed by an annular pole shoe portion according to an embodiment of the present invention; Figure 6 A schematic structural diagram of an annular pole shoe portion according to another embodiment of the present invention; Figure 7A schematic diagram of a portion of the structure of a scanning system according to an embodiment of the present invention; Figure 8 A schematic diagram of a scanning system according to an embodiment of the present invention achieving secondary deflection of an electron beam; Figure 9 A schematic diagram of a scanning system according to an embodiment of the present invention achieving a single deflection of an electron beam. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0027] refer to Figures 1 to 7 On the one hand, the present invention provides a scanning system, including: an integrated electromagnetic lens structure, the integrated electromagnetic lens structure includes a main body 10 and an annular pole shoe 11 spaced apart from each other, the annular pole shoe 11 is electrically insulated from the main body 10 and the magnetic circuit is continuous; the annular pole shoe 11 includes a plurality of deflection groups, the deflection groups are electrically insulated from each other and the magnetic circuit is continuous; the voltage loaded on the main body 10 is different from the voltage loaded on the annular pole shoe, and the voltage loaded on each deflection group is different. When the main body 10 is loaded with the corresponding voltage and the deflection group is loaded with the corresponding voltage, the integrated electromagnetic lens structure simultaneously realizes focusing and deflection of the electron beam.

[0028] The deflection groups are arranged along the circumference of the annular pole shoe 11 , the magnetic field for focusing the electron beam is formed by the main body 10 and the annular pole shoe 11 , and the electric field for deflecting the electron beam is formed by the annular pole shoe 11 .

[0029] In some embodiments, the voltage applied to the main body 10 is a first voltage, which may be a ground voltage, or may be 3000V or 5000V.

[0030] It should be noted that the scanning system provided by the present invention can be applied to a high-resolution scanning electron microscope, and can also be applied to a scanning electron microscope for feature size measurement.

[0031] In some embodiments, the main body 10 includes a magnetic shell 101 and a coil 102. The magnetic shell 101 has a accommodating cavity, and the coil 102 is arranged in the accommodating cavity. The annular pole shoe portion 11 is the end of the integrated electromagnetic lens structure that outputs the electron beam to the sample. The annular pole shoe portion 11 is annular, the integrated electromagnetic lens structure has a central axis, and the central axis of the integrated electromagnetic lens structure has an electron beam channel 20. The magnetic shell 101, the accommodating cavity, the coil 102 and the annular pole shoe portion 11 are all arranged in an outer ring of the electron beam channel 20, and the magnetic shell 101 has an annular opening on the side facing the electron beam channel 20. The accommodating cavity is connected to the electron beam channel 20 through the annular opening, and the annular pole shoe portion 11 is located on the side of the annular opening facing the sample, wherein the coil 102, the magnetic shell 101 and the annular pole shoe portion 11 jointly form a magnetic field that converges the electron beam.

[0032] In some embodiments, the integrated electromagnetic lens structure may be a non-immersed magnetic lens, a semi-immersed magnetic lens, or a fully-immersed magnetic lens.

[0033] Furthermore, when the deflection group is loaded with a corresponding voltage, the annular pole shoe portion 11 forms a quadrupole deflection field, and the electron beam is deflected under the action of the quadrupole deflection field.

[0034] Furthermore, the annular pole shoe portion 11 includes four deflection groups, namely a first deflection group, a second deflection group, a third deflection group, and a fourth deflection group, arranged in sequence. The first and third deflection groups are symmetrical, and the second and fourth deflection groups are symmetrical. The voltages of each deflection group are adjustable: the first deflection group is loaded with a positive second voltage, the third deflection group is loaded with a negative second voltage, the second deflection group is loaded with a positive third voltage, and the fourth deflection group is loaded with a negative third voltage, with the second and third voltages being different. In other words, the voltages applied to two symmetrically arranged deflection groups have the same value but different directions, and the voltages applied to any two adjacent deflection groups also have different values, thereby forming a quadrupole deflection field.

[0035] For further reference, Figure 3 Each deflection group includes a sub-deflection unit 110, and the sub-deflection units 110 are electrically insulated and have continuous magnetic circuits. Figure 5 shown.

[0036] Furthermore, each sub-deflecting portion 110 is connected via a first sub-connecting portion to form an annular pole shoe portion 11 , and the first sub-connecting portion is made of insulating material.

[0037] In some embodiments, each deflection group includes N spaced-apart sub-deflection units, where N is an integer greater than 1, and the sub-deflection units are electrically insulated and have continuous magnetic paths.

[0038] In some embodiments, reference Figure 6 The annular pole shoe portion 11 includes four deflection groups, which are a first deflection group, a second deflection group, a third deflection group and a fourth deflection group arranged in sequence. The sub-deflection portion of the first deflection group is defined as a first sub-deflection portion 111. The first deflection group includes three spaced first sub-deflection portions 111. The sub-deflection portion of the second deflection group is defined as a second sub-deflection portion 112. The second deflection group includes three spaced second sub-deflection portions 112. The sub-deflection portion of the third deflection group is defined as a third sub-deflection portion 113. The third deflection group includes three spaced third sub-deflection portions 113. The sub-deflection portion of the fourth deflection group is defined as a fourth sub-deflection portion 11 4. The fourth deflection group includes three spaced-apart fourth sub-deflecting units 114. The first deflection group and the third deflection group are symmetrical, and the second deflection group and the fourth deflection group are symmetrical. The first deflection group is loaded with a positive second voltage, the third deflection group is loaded with a negative second voltage, the second deflection group is loaded with a positive third voltage, and the fourth deflection group is loaded with a negative third voltage. In some examples, the positive second voltage can be 30V, the negative second voltage is 30V, the positive third voltage is 50V, and the negative third voltage is -50V. In this way, by using different voltages loaded by the first deflection group, the second deflection group, the third deflection group, and the fourth deflection group, a four-level deflection field is formed to achieve deflection of the electron beam.

[0039] In some embodiments, each sub-deflecting portion 110 is fan-shaped, and each sub-deflecting portion 110 is arranged along the circumference of the annular pole shoe portion.

[0040] In some embodiments, the distance between two adjacent sub-deflecting portions 110 is not less than a fourth preset distance. In some examples, the fourth preset distance is in the range of 1.5 mm to 2.5 mm.

[0041] In some embodiments, the first sub-connecting portion is made of a non-magnetic insulating material, and the distance between two adjacent sub-deflecting portions 110 is no greater than a fifth predetermined distance. In some examples, the fifth predetermined distance is within a range of 4.5 mm to 5 mm.

[0042] In some embodiments, the first sub-connecting portion may also be made of a magnetically conductive insulating material, and the distance between two adjacent sub-deflecting portions 110 is no greater than a sixth preset distance. In some examples, the sixth preset distance is in the range of 5 mm to 5.5 mm.

[0043] It should be noted that in order to ensure electrical insulation and continuous magnetic circuit between each sub-deflection unit 110, when the first sub-connecting part is a non-magnetic insulating material, it is necessary to set the distance between two adjacent sub-deflection units 110 to be neither too large nor too small. Although a too large distance between two adjacent sub-deflection units 110 can ensure better insulation, it may cause discontinuity of the magnetic circuit. Although a too small distance between two adjacent sub-deflection units 110 can ensure the continuity of the magnetic circuit, it may cause voltage breakdown of the insulating layer. Therefore, it is necessary to set the distance between two adjacent sub-deflection units 110 within a reasonable range to ensure both electrical insulation and continuity of the magnetic circuit.

[0044] When the first sub-connecting portion is made of a magnetically conductive insulating material, the distance between two adjacent sub-deflecting portions 110 needs to be set to be neither too large nor too small. If the distance between two adjacent sub-deflecting portions 110 is too large, although the magnetic circuit will not be discontinuous due to the magnetic conductive properties of the first sub-connecting portion, the size of the portion of the annular pole shoe portion 11 that does not require voltage loading will be too large, thereby resulting in insufficient deflection strength of the four-level deflection field and affecting the deflection performance. If the distance between two adjacent sub-deflecting portions 110 is too small, the voltage may break through the first sub-connecting portion. Therefore, the distance between two adjacent sub-deflecting portions 110 needs to be set within a reasonable range to ensure both electrical insulation and magnetic circuit continuity.

[0045] Furthermore, the integrated electromagnetic lens structure further includes an insulating connection portion, wherein the annular pole shoe portion 11 is connected to the main body portion 10 via the insulating connection portion, and the distance between the annular pole shoe portion 11 and the main body portion 10 is not less than a first predetermined distance. In some examples, the first predetermined distance is in the range of 0.3 mm to 0.7 mm.

[0046] Furthermore, the insulating connection portion is made of a non-magnetic insulating material, and the distance between the annular pole shoe portion 11 and the main body portion 10 is no greater than a second preset distance. In some examples, the second preset distance is in the range of 1 mm to 2 mm.

[0047] Furthermore, the insulating connection portion is made of a magnetically conductive insulating material, and the distance between the annular pole shoe portion 11 and the main body portion 10 is no greater than a third preset distance. In some examples, the third preset distance is in the range of 2.5 mm to 3.5 mm.

[0048] In some embodiments, the magnetically conductive insulating material may be ferrite ceramic.

[0049] It should be noted that in order to ensure electrical insulation and continuous magnetic circuit between the annular pole shoe portion 11 and the main body portion 10, an insulating connection portion (magnetic insulating material or non-magnetic insulating material) needs to be set. The distance between the annular pole shoe portion 11 and the main body portion 10 cannot be too large or too small. Although a too large distance can ensure better insulation, it may cause discontinuity of the magnetic circuit. Although a too small distance can ensure the continuity of the magnetic circuit, it may cause voltage breakdown of the insulating material. Therefore, it is necessary to set the distance between the annular pole shoe portion 11 and the main body portion 10 within a reasonable range, so as to ensure stable electrical insulation between the annular pole shoe portion 11 and the main body portion 10, and to ensure the continuity of the magnetic circuit between the annular pole shoe portion 11 and the main body portion 10.

[0050] refer to Figure 4 When the insulating connection part is designed reasonably, the magnetic field distribution for focusing formed by the integrated electromagnetic lens structure is not affected by the insulating connection part.

[0051] Furthermore, the scanning system also includes a condenser, which is located on the side of the integrated electromagnetic lens structure away from the sample, and is used to achieve preliminary convergence of the electron beam; the integrated electromagnetic lens structure serves as an objective lens, and the electron beam after preliminary convergence is focused on the sample through the objective lens.

[0052] In some embodiments, the condenser can be an electrostatic lens; in other embodiments, the condenser can also be an electromagnetic lens. In some examples, the condenser can be a three-stage non-immersion electrostatic lens, and the diameter of the condenser pole piece can be in the range of 4 mm to 6 mm.

[0053] In some embodiments, the pole shoe opening diameter of the integrated electromagnetic lens structure may be in the range of 7 mm to 9 mm.

[0054] Furthermore, the scanning system further includes a first deflecting member 30 , which is disposed in the electron beam channel 20 of the integrated electromagnetic lens structure, and is located on a side of the annular pole shoe portion 11 away from the sample.

[0055] In some embodiments, the first deflector 30 may be a magnetic deflector. In other embodiments, the first deflector 30 may be an electric deflector.

[0056] In some examples, when the first deflection element 30 is a magnetic deflection element, the first deflection element 30 is a quadrupole coil, the diameter of each pole coil may be in the range of 5 mm to 7 mm, and the number of turns of each pole coil may be in the range of 180 turns to 220 turns.

[0057] In some examples, when the first deflection element 30 is an electric deflection element, the first deflection element 30 is a four-stage electrostatic deflector, the pitch of the four-stage electrostatic deflector can be in the range of 1.5 mm to 2.2 mm, and the diameter of each electrode is in the range of 9 mm to 11 mm.

[0058] It should be noted that the integrated electromagnetic lens structure and the first deflection element 30 are both coaxially arranged along the main axis of the incident electron beam.

[0059] Furthermore, the scanning system further includes a control component, which is used to regulate the voltage applied to the annular pole shoe portion 11 and to regulate the voltage applied to the first deflection member 30 .

[0060] In some examples, the working principle of the scanning system is as follows: the incident electron beam is first initially converged by the condenser, and then focused and deflected by the integrated electromagnetic lens structure to act on the sample surface; alternatively, the electron beam initially converged by the condenser is focused by the integrated electromagnetic lens structure, and deflected twice by the integrated electromagnetic lens structure and the first deflection member 30 before acting on the sample surface; the signal electrons generated on the sample surface are accelerated by the accelerating electrode and then received by the detector.

[0061] refer to Figures 1 to 9 On the other hand, the present invention provides an electron beam control method, including: providing the above-mentioned scanning system, the scanning system including an integrated electromagnetic lens structure, the integrated electromagnetic lens structure including a main body 10 and an annular pole shoe portion 11, the annular pole shoe portion 11 including a plurality of deflection groups; the electron beam control method includes: regulating the main body 10 and the annular pole shoe portion 11 to load different voltages, and regulating each deflection group to load a different voltage, so that the integrated electromagnetic lens structure can simultaneously achieve focusing and deflection of the electron beam.

[0062] In some examples, reference Figure 6The annular pole shoe portion 11 includes four deflection groups, which are a first deflection group, a second deflection group, a third deflection group, and a fourth deflection group arranged in sequence. The sub-deflection portion of the first deflection group is defined as a first sub-deflection portion 111. The first deflection group includes three spaced first sub-deflection portions 111. The sub-deflection portion of the second deflection group is defined as a second sub-deflection portion 112. The second deflection group includes three spaced second sub-deflection portions 112. The sub-deflection portion of the third deflection group is defined as a third sub-deflection portion 113. The third deflection group includes three spaced third sub-deflection portions 113. The sub-deflection portion of the fourth deflection group is defined as a fourth sub-deflection portion 114. The fourth deflection group includes three spaced fourth sub-deflection portions 114. The first deflection group and the third deflection group are symmetrical, and the second deflection group and the fourth deflection group are symmetrical. The first deflection group is loaded with a positive second voltage, the third deflection group is loaded with a negative second voltage, the second deflection group is loaded with a positive third voltage, and the fourth deflection group is loaded with a negative third voltage. The positive second voltage, the negative second voltage, the positive third voltage, and the negative third voltage are all voltages that change in the form of a triangular wave. In some examples, at a certain moment, the positive second voltage can be 30V, the negative second voltage can be 30V, the positive third voltage can be 50V, and the negative third voltage can be -50V. In this way, by using different voltages loaded by the first deflection group, the second deflection group, the third deflection group, and the fourth deflection group, a four-level deflection field is formed to achieve deflection of the electron beam.

[0063] Furthermore, regulating the main body 10 and the annular pole piece 11 to load different voltages, and regulating each deflection group to load different voltages includes regulating the main body 10 to be at a first voltage, and regulating the voltage of each deflection group within a preset range to achieve deflection fields of different intensities.

[0064] Furthermore, regulating the voltage of each deflection group within a preset range includes regulating each deflection group to apply a voltage on top of the first voltage.

[0065] In some embodiments, when the first voltage is 0V, regulating each deflection group to load a voltage on the first voltage includes regulating the voltage of each deflection group to change with the first voltage as an offset.

[0066] For details, please refer to Figure 6 When the control main body 10 is in a first voltage of 0V, the voltages of the first deflection group, the second deflection group, the third deflection group and the fourth deflection group are increased or decreased on the basis of 0V. For example, when the target voltages of the first deflection group, the second deflection group, the third deflection group and the fourth deflection group are +30, +50, -30 and -50, a voltage of +30V is added on the basis of 0V to make the first deflection group reach the target voltage of +30V, and a voltage of -50V is added on the basis of 0V to make the fourth deflection group reach the target voltage of -50V.

[0067] In some embodiments, the voltage of each deflection group is controlled to vary in a triangular wave pattern within a preset range, where the preset range is the range between the minimum and maximum voltages of the triangular wave pattern. In some examples, the preset range is -100V to 100V. In other examples, depending on actual needs, the preset range can also be set to -200V to 200V.

[0068] Furthermore, the scanning system also includes a first deflection member 30 and a control assembly. The electron beam control method further includes: using the control assembly to regulate the voltage applied to the annular pole shoe 11 to achieve a primary deflection of the electron beam, thereby achieving deflection scanning within a first field of view through the single deflection; or using the control assembly to regulate the voltage applied to the first deflection member 30 to achieve a primary deflection of the electron beam, and regulating the voltage applied to the annular pole shoe 11 to achieve a secondary deflection of the electron beam, thereby achieving deflection scanning within a second field of view through the two deflections; wherein the first field of view is smaller than the second field of view. In this way, through the hierarchical control of the first deflection member 30 and the annular pole shoe 11, multi-field compatibility can be achieved, and deflection scanning within two different fields of view can be achieved simultaneously with focusing using only the first deflection member 30 and the objective lens. This reduces the number of components in the scanning system while still ensuring that the scanning system has comprehensive functionality.

[0069] It should be noted that for scanning within a small field of view, since the annular pole shoe 11 is positioned sufficiently close to the sample surface, better resolution can be achieved. Scanning using only the annular pole shoe 11 is completely sufficient and does not significantly affect resolution, etc., and single-layer deflection is easier to debug and calibrate. For scanning within a large field of view, the first deflection element 30 can be activated. In this way, the electron beam undergoes two deflections, passing through the center of the objective lens to reach the sample surface, allowing scanning to be completed within a larger field of view while ensuring that resolution is not significantly degraded.

[0070] In summary, the scanning system and electron beam control method provided by the present invention integrate the focusing and deflection functions into the same pole shoe, thereby reducing the independent lens components, thereby reducing the occupied space of the independent lens components, and avoiding the assembly of multiple components, significantly reducing the assembly complexity, eliminating the need for multi-stage lens alignment, and reducing the risk of assembly errors. The deflection electric field formed by the annular pole shoe portion 11 acts on the near-sample area, alleviating long-range interference, and also alleviating the electromagnetic field of the multi-stage lens from interfering with the main focusing magnetic field, alleviating the signal interference problem, and helping to improve resolution.

[0071] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0072] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A scanning system, characterized in that: include: An integrated electromagnetic lens structure, comprising a main body portion and an annular pole shoe portion spaced apart from each other, wherein the annular pole shoe portion is electrically insulated from the main body portion and has a continuous magnetic circuit; The annular pole shoe portion includes a plurality of deflection groups, each deflection group is electrically insulated and has a continuous magnetic circuit; The voltage loaded on the main body is different from the voltage loaded on the annular pole shoe, and the voltage loaded on each deflection group is different. When the main body is loaded with corresponding voltages and the deflection groups are loaded with corresponding voltages, the integrated electromagnetic lens structure simultaneously realizes focusing and deflection of the electron beam.

2. The scanning system according to claim 1, wherein: When the deflection group is loaded with a corresponding voltage, the annular pole shoe portion forms a quadrupole deflection field, and the electron beam is deflected under the action of the quadrupole deflection field.

3. The scanning system according to claim 2, wherein: The annular pole shoe portion includes four deflection groups, which are a first deflection group, a second deflection group, a third deflection group, and a fourth deflection group arranged in sequence, wherein the first deflection group and the third deflection group are symmetrical, and the second deflection group and the fourth deflection group are symmetrical; The voltage of each deflection group is adjustable. The voltage loaded on the first deflection group is a positive second voltage, the voltage loaded on the third deflection group is a negative second voltage, the voltage loaded on the second deflection group is a positive third voltage, and the voltage loaded on the fourth deflection group is a negative third voltage. The second voltage is different from the third voltage.

4. The scanning system according to claim 1, wherein: Each of the deflection groups includes a sub-deflection unit; Alternatively, each of the deflection groups includes N spaced-apart sub-deflection units, where N is an integer greater than 1, and the sub-deflection units are electrically insulated from each other and have continuous magnetic circuits.

5. The scanning system according to claim 4, characterized in that The sub-deflecting portions are connected via a first sub-connecting portion to form the annular pole shoe portion, and the first sub-connecting portion is made of insulating material.

6. The scanning system according to claim 1, wherein: The integrated electromagnetic lens structure further includes an insulating connection portion, the annular pole shoe portion is connected to the main body portion via the insulating connection portion, and the distance between the annular pole shoe portion and the main body portion is not less than a first preset distance.

7. The scanning system according to claim 6, wherein: The insulating connection portion is made of a non-magnetic insulating material, and the distance between the annular pole shoe portion and the main body portion is no greater than a second preset distance; Alternatively, the insulating connection portion is made of a magnetically conductive insulating material, and the distance between the annular pole shoe portion and the main body portion is no greater than a third preset distance.

8. The scanning system according to claim 1, wherein: The scanning system further comprises a condenser lens, which is located on a side of the integrated electromagnetic lens structure away from the sample and is used to achieve preliminary convergence of the electron beam; The integrated electromagnetic lens structure serves as an objective lens, and the electron beam after preliminary convergence is focused on the sample through the objective lens.

9. The scanning system according to claim 1, wherein: The scanning system further includes a first deflecting member, which is disposed in the electron beam channel of the integrated electromagnetic lens structure and is located on a side of the annular pole shoe portion away from the sample.

10. The scanning system according to claim 9, wherein: The scanning system further includes a control component, which is used to regulate the voltage applied to the annular pole shoe portion and to regulate the voltage applied to the first deflection element.

11. An electron beam control method, characterized in that: include: A scanning system according to any one of claims 1 to 10 is provided, wherein the scanning system comprises an integrated electromagnetic lens structure, the integrated electromagnetic lens structure comprises a main body portion and an annular pole shoe portion, the annular pole shoe portion comprises a plurality of deflection groups; The electron beam control method comprises: The main body and the annular pole shoe are regulated to load different voltages, and each deflection group is regulated to load different voltages, so that the integrated electromagnetic lens structure can simultaneously achieve focusing and deflection of the electron beam.

12. The electron beam control method according to claim 11, wherein: Regulating the main body and the annular pole shoe to load different voltages, and regulating each deflection group to load a different voltage includes: The main body is regulated to be at a first voltage, and the voltage of each deflection group is regulated within a preset range to achieve deflection fields of different intensities.

13. The electron beam control method according to claim 12, wherein: Regulating the voltage of each deflection group within a preset range includes: Each of the deflection groups is regulated to apply a voltage on top of the first voltage.

14. The electron beam control method according to claim 11, wherein: The scanning system further includes a first deflection member and a control assembly; The electron beam control method further comprises: The control component is used to regulate the voltage applied to the annular pole shoe portion to achieve a single deflection of the electron beam, and a deflection scan of the first field of view is achieved through the single deflection; Alternatively, the control component is used to regulate the voltage applied to the first deflection member to achieve a primary deflection of the electron beam, and the voltage applied to the annular pole shoe is regulated to achieve a secondary deflection of the electron beam, thereby achieving deflection scanning within a second field of view through the two deflections; The first field of view is smaller than the second field of view.

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