Off-axis electrostatic deflector for charged particle beam and deflection scanning method

Abstract

The invention provides an off-axis electrostatic deflector for a charged particle beam and a deflection scanning method. The off-axis electrostatic deflector comprises an incident side electrode, a focusing electrode, at least one off-axis electrode, an emergent side electrode and a shifter, the incident side electrode, the focusing electrode, the off-axis electrode and the emergent side electrode are all provided with through holes and are coaxially arranged in parallel according to a preset arrangement sequence, the potential of the incident side electrode, the potential of the focusing electrode and the potential of the off-axis electrode are different from each other and are fixed, and the potential of the emergent side electrode is the same as the potential of the incident side electrode and is fixed; the off-axis electrode is mechanically connected with the displacer, and the displacer is used for controlling the displacement of the off-axis electrode so as to form a non-axisymmetric electric field to enable the charged particle beam to continuously deflect and scan. The problem of charged particle beam defocusing caused by a vertical electric field is weakened, the problem of charged particle beam deflection errors caused by voltage ripples generated by voltage changes is weakened, and then the charged particle beam deflection precision is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of charged particle beam transmission, in particular to an off-axis electrostatic deflector for charged particle beam and a deflection scanning method. BACKGROUND

[0002] The electrostatic deflector is widely used in the fields of oscilloscope, electron beam lithography system and detection system, especially in the nanometer precision patterning and defect detection equipment, the electrostatic deflection lens is needed to make the charged particle beam realize high-precision deflection scanning. Therefore, in the high-precision industry, how to ensure the deflection scanning precision of the charged particle beam of the electrostatic deflector becomes a key research problem.

[0003] At present, in the existing electrostatic deflection technology, the planar deflector usually adopts parallel electrode configuration, and the unidirectional deflection of the particle beam is realized through the vertical electric field formed between the electrode plates; or the multi-pole deflector realizes the compound deflection of the charged particles in the two-dimensional plane through the ring arrangement of multiple groups of electrodes. However, the existing deflector realizes the deflection scanning of the charged particle beam by applying corresponding voltage to the electrodes, and the direction of the deflection electric field generated is perpendicular to the optical axis, which is easy to cause the defocusing of the charged particle beam, and the voltage ripple caused by the change of the voltage is easy to cause the charged particle beam to have a large deflection error, resulting in poor deflection precision of the charged particle beam. SUMMARY

[0004] In order to solve the above problems, the present application provides an off-axis electrostatic deflector for charged particle beam and a deflection scanning method, which realizes the deflection scanning of the charged particle beam in the deflection electric field which is not completely perpendicular to the direction of the optical axis, can weaken the defocusing problem of the charged particle beam caused by the vertical electric field; in addition, the voltage does not need to be changed during the deflection scanning process, which can weaken the defocusing problem of the charged particle beam caused by the voltage ripple generated by the change of the voltage, thereby improving the deflection precision of the charged particle beam.

[0005] In order to achieve the above purpose, the embodiment of the present application provides an off-axis electrostatic deflector for charged particle beam, which comprises: an incident side electrode, a focusing electrode, at least one off-axis electrode, an exit side electrode and a displacer; the incident side electrode, the focusing electrode, the off-axis electrode and the exit side electrode are all provided with through holes for passing the charged particle beam; the incident side electrode, the focusing electrode, the off-axis electrode and the exit side electrode are coaxially and parallelly arranged in a predetermined arrangement order, wherein the incident side electrode is fixedly arranged at the first position of the predetermined arrangement order, and the exit side electrode is fixedly arranged at the last position of the predetermined arrangement order; the potential of the incident side electrode, the potential of the focusing electrode and the potential of the off-axis electrode are different and fixedly unchanged, and the potential of the exit side electrode is the same as that of the incident side electrode and is fixedly unchanged; the off-axis electrode is mechanically connected with the displacer, and the displacer is used for controlling the displacement of the off-axis electrode to form a non-axisymmetric electric field to continuously deflect and scan the charged particle beam.

[0006] The embodiment of the present application provides a kind of off-axis electrostatic deflector for charged particle beam, the potential of incident side electrode, focusing electrode, off-axis electrode and exit side electrode is fixed, to move off-axis electrode with shifter control, to form non-axisymmetric electric field (equivalent to deflection electric field) to charged particle beam and be offset scanning, while since off-axis electrode moves with shifter control changes the distribution of non-axisymmetric electric field, charged particle beam can be deflected scanning in the deflection electric field that is not completely perpendicular to optical axis direction, the problem of defocusing of charged particle beam caused by vertical electric field can be weakened;In addition, voltage does not need to be changed during deflection scanning, the problem of defocusing of charged particle beam caused by voltage ripple due to voltage change can be weakened, to improve the deflection accuracy of charged particle beam.

[0007] Further, through hole is arranged in the center of incident side electrode, focusing electrode, off-axis electrode and exit side electrode, and the through hole can be arranged in any rotationally symmetric shape.

[0008] Further, if off-axis electrode is provided as two, the off-axis electrode includes: first off-axis electrode and second off-axis electrode;First off-axis electrode and second off-axis electrode are coaxially parallel, and focusing electrode is coaxially parallel between first off-axis electrode and second off-axis electrode;First off-axis electrode is mechanically connected with shifter, and shifter is used to control first off-axis electrode to move along first direction perpendicular to preset optical axis, so that charged particle beam is deflected along first direction;Second off-axis electrode is mechanically connected with shifter, and shifter is used to control second off-axis electrode to move along second direction perpendicular to preset optical axis and perpendicular to first direction, so that the charged particle beam moves along second direction.

[0009] In the above scheme, the off-axis electrostatic deflector is provided with two off-axis electrodes, and the two off-axis electrodes are arranged on the two sides of the focusing electrode coaxially and in parallel, so that when the first off-axis electrode moves along the first direction perpendicular to the preset optical axis, the charged particle beam is deflected along the first direction, and when the second off-axis electrode moves along the second direction perpendicular to the preset optical axis and perpendicular to the first direction, the charged particle beam is deflected along the second direction. By arranging two off-axis electrodes to move in different directions, the charged particle beam is deflected and scanned in different directions. By controlling the movement of off-axis electrode with shifter to change the distribution of non-axisymmetric electric field, the charged particle beam can be deflected and scanned in the deflection electric field that is not completely perpendicular to optical axis direction, and the problem of defocusing of charged particle beam caused by vertical electric field can be weakened. In addition, voltage does not need to be changed during deflection scanning, the problem of defocusing of charged particle beam caused by voltage ripple due to voltage change can be weakened, to improve the deflection accuracy of charged particle beam.

[0010] Further, the first off-axis electrode is moved in the first direction by a distance less than or equal to a preset first distance value, wherein the preset first distance value is set according to a through-hole aperture of the first off-axis electrode; and the second off-axis electrode is moved in the second direction by a distance less than or equal to a preset second distance value, wherein the preset second distance value is set according to a through-hole aperture of the second off-axis electrode.

[0011] In the above scheme, the movement distance of the first off-axis electrode is limited to be less than or equal to the preset first distance value according to the through-hole of the first off-axis electrode, and the movement distance of the second off-axis electrode is limited to be less than or equal to the preset second distance value according to the through-hole of the second off-axis electrode, so that the charged particle beam can pass through the off-axis electrodes, thereby providing a guarantee for subsequent simultaneous deflection scanning of the charged particle beam.

[0012] Further, the potential of the first off-axis electrode and the potential of the second off-axis electrode are set to be the same; if the first off-axis electrode is moved, the incident-side electrode, the first off-axis electrode and the focusing electrode form a first electric field region, and the first electric field region is used to control the charged particle beam to deviate in the first direction. If the second off-axis electrode is moved, the focusing electrode, the second off-axis electrode and the exit-side electrode form a second electric field region, and the second electric field region is used to control the charged particle beam to deviate in the second direction.

[0013] In the above scheme, when the first off-axis electrode is moved, the incident-side electrode, the first off-axis electrode and the focusing electrode form a first electric field region, and the charged particle beam is deflected and scanned in the first direction; when the second off-axis electrode is moved, the first off-axis electrode is fixed, the focusing electrode, the first off-axis electrode and the exit-side electrode form a second electric field region, and the charged particle beam is deflected and scanned in the second direction. Only the movement of a single off-axis electrode effectively prevents the deflection direction of the charged particle beam from being confused, and the movement of the off-axis electrode controlled by the shifter changes the distribution of the non-axisymmetric electric field, so that the charged particle beam can be deflected and scanned in a deflection electric field that is not completely perpendicular to the optical axis direction, and the problem of defocusing of the charged particle beam caused by the vertical electric field can be weakened. In addition, the voltage does not need to be changed during the deflection scanning process, and the problem of defocusing of the charged particle beam caused by voltage ripples due to voltage changes can be weakened, thereby improving the deflection accuracy of the charged particle beam.

[0014] Further, if the off-axis electrode is one, the focusing electrode is coaxially parallel and adjacent to the off-axis electrode, and the off-axis electrode is mechanically connected to the shifter, and the shifter is used to control the first off-axis electrode to move in the first direction or the second direction, so that the charged particle beam is deflected in the first direction or the second direction.

[0015] In the above scheme, the off-axis electrostatic deflector is provided with only one off-axis electrode, and the focusing electrode is coaxially parallel and adjacent to the off-axis electrode, so that when the off-axis electrode moves in different directions, a deflection electric field is generated to cause the charged ion beam to deflect and scan in the deflection electric field. The shifter is used to control the movement of the off-axis electrode to change the distribution of the non-axisymmetric electric field, so as to realize the deflection and scanning of the charged particle beam in the deflection electric field which is not completely perpendicular to the optical axis direction, and to weaken the problem of defocusing of the charged particle beam caused by the vertical electric field; in addition, the voltage does not need to be changed during the deflection and scanning process, so as to weaken the problem of defocusing of the charged particle beam caused by voltage ripples due to voltage changes, thereby improving the deflection accuracy of the charged particle beam.

[0016] Further, if the off-axis electrode moves along the first direction, the focusing electrode and the off-axis electrode form a third electric field region for controlling the charged particle beam to deflect and scan along the first direction. If the off-axis electrode moves along the second direction, the focusing electrode and the off-axis electrode form a fourth electric field region for controlling the charged particle beam to deflect and scan along the second direction.

[0017] In the above scheme, when the off-axis electrode moves along the first direction, the focusing electrode and the off-axis electrode form a third electric field region to control the charged particle beam to deflect and scan in the first direction, and when the off-axis electrode moves along the second direction, the focusing electrode and the off-axis electrode form a fourth electric field region to control the charged particle beam to deflect and scan in the second direction. The shifter is used to control the movement of the off-axis electrode to change the distribution of the non-axisymmetric electric field, so as to realize the deflection and scanning of the charged particle beam in the deflection electric field which is not completely perpendicular to the optical axis direction, and to weaken the problem of defocusing of the charged particle beam caused by the vertical electric field; in addition, the voltage does not need to be changed during the deflection and scanning process, so as to weaken the problem of defocusing of the charged particle beam caused by voltage ripples due to voltage changes, thereby improving the deflection accuracy of the charged particle beam.

[0018] The embodiment of the present application also provides a deflection scanning method for a charged particle beam, comprising: receiving a charged particle beam incident from an incident side electrode along a preset optical axis; controlling a shifter to move an off-axis electrode to generate a non-axisymmetric electric field; and controlling the charged particle beam to continuously deflect and scan based on the non-axisymmetric electric field.

[0019] The embodiment of the present application provides a deflection scanning method for a charged particle beam, the potential of an incident side electrode, a focusing electrode, an off-axis electrode and an exit side electrode is fixed, the off-axis electrode is controlled to move by a shifter, so that a non-axisymmetric electric field (deflection electric field) is formed to perform deflection scanning on the charged particle beam. Meanwhile, the off-axis electrode is controlled to move by the shifter to change the distribution of the non-axisymmetric electric field, deflection scanning of the charged particle beam in the deflection electric field which is not completely perpendicular to the optical axis direction is realized, and the defocus problem of the charged particle beam caused by the vertical electric field can be weakened; in addition, the voltage does not need to be changed in the deflection scanning process, and the defocus problem of the charged particle beam caused by voltage ripples due to voltage changes can be weakened, so that the deflection accuracy of the charged particle beam is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure One ;

[0021] Figure 2 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Two ;

[0022] Figure 3 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Three ;

[0023] Figure 4 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Four ;

[0024] Figure 5 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Five ;

[0025] Figure 6 An improved module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure One ;

[0026] Figure 7 An improved module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Two ;

[0027] Figure 8 A step flow diagram of a deflection scanning method for a charged particle beam is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0028] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0029] Embodiment 1

[0030] The embodiment of the present application provides an off-axis electrostatic deflector for a charged particle beam, comprising: an incident side electrode 11, at least one off-axis electrode 12, a focusing electrode 13, an exit side electrode 14 and a displacement device 2; the incident side electrode 11, the focusing electrode 13, the off-axis electrode 12 and the exit side electrode 14 are all provided with a through hole 3 for passing the charged particle beam. The incident side electrode 11, the focusing electrode 13, the off-axis electrode 12 and the exit side electrode 14 are coaxially and parallelly arranged in a preset arrangement order, wherein the incident side electrode 11 is fixedly arranged at the first position of the preset arrangement order, and the exit side electrode 14 is fixedly arranged at the last position of the preset arrangement order. The electric potential of the incident side electrode 11, the electric potential of the focusing electrode 13 and the electric potential of the off-axis electrode 12 are different and fixed, and the electric potential of the exit side electrode 14 is the same as and fixed with the electric potential of the incident side electrode 11. The off-axis electrode 12 is mechanically connected with the displacement device 2, and the displacement device 2 is used for controlling the displacement of the off-axis electrode 12 to form a non-axisymmetric electric field to continuously deflect and scan the charged particle beam. The through hole 3 is arranged at the center of the incident side electrode 11, the focusing electrode 13, the off-axis electrode 12 and the exit side electrode 14, and the through hole 3 can be arranged in any rotationally symmetric body shape.

[0031] A specific embodiment can be implemented, referring to Figure 1 , Figure 1 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam provided by an embodiment of the present application Figure One . As Figure 1As shown, in the xyz coordinate system, the off-axis electrostatic deflector is composed of an incident side electrode 11, one off-axis electrode 12, two focusing electrodes 13, and an exit side electrode 14, wherein the two focusing electrodes include a first focusing electrode 13a and a second focusing electrode 13b. A through hole 3 is arranged at the center of the incident side electrode 11, the focusing electrode 13, the off-axis electrode 12, and the exit side electrode 14, and the through hole 3 can be arranged in any rotationally symmetric shape, and in this embodiment, a cylindrical shape is preferred. The incident side electrode 11, at least one off-axis electrode 12, the focusing electrode 13, and the exit side electrode 14 are arranged in parallel in the z direction, arranged in order from top to bottom, with the incident side electrode 11 at the beginning of the arrangement order and the exit side electrode 14 at the end of the arrangement order. The arrangement order of the off-axis electrode 12 and the focusing electrode 13 is obtained according to the number of electrodes arranged. For example, in a 5-electrode off-axis electrostatic deflector, if two off-axis electrodes 12, i.e., a first off-axis electrode 12a and a second off-axis electrode 12b, are arranged, the order of arrangement from top to bottom is the incident side electrode 11, the first off-axis electrode 12a, the focusing electrode 13, the second off-axis electrode 12b, and the exit side electrode 14. At this time, the first off-axis electrode 12a and the second off-axis electrode 12b are movable, the incident side electrode 11, the focusing electrode 13, and the exit side electrode 14 are fixedly arranged and have fixed potentials, the potentials of the incident side electrode 11 and the exit side electrode 14 are the same and are denoted as a first potential V1, the potentials of the first off-axis electrode 12a and the second off-axis electrode 12b are the same and are denoted as a second potential V2, the potential of the focusing electrode 13 is denoted as a third potential V3, and the first potential V1, the second potential V2, and the third potential V3 are all different. Furthermore, the displacer 2 is mechanically connected to the first off-axis electrode 12a or the second off-axis electrode 12b to control the movement of the first off-axis electrode 12a or the second off-axis electrode 12b in the respective direction, thereby forming a non-axisymmetric electric field to continuously deflect and scan the charged particle beam in the respective direction. If one off-axis electrode 12 and two focusing electrodes 13 are arranged, the focusing electrodes 13 include the first focusing electrode 13a and the second focusing electrode 13b, and the order of arrangement from top to bottom is the incident side electrode 11, the first focusing electrode 13a, the off-axis electrode 12, the second focusing electrode 13b, and the exit side electrode 14. At this time, the incident side electrode 11, the first focusing electrode 13a, the second focusing electrode 13b, and the exit side electrode 14 are fixedly arranged and have fixed potentials, the off-axis electrode 12 is movable, the potentials of the incident side electrode 11 and the exit side electrode 14 are the same and are denoted as a first potential V1, the potential of the off-axis electrode 12 is denoted as a second potential V2, the potentials of the first focusing electrode 13a and the second focusing electrode 13b are the same and are denoted as a third potential V3, and the first potential V1, the second potential V2, and the third potential V3 are all different. Furthermore, the displacer 2 is mechanically connected to the off-axis electrode 12 to control the movement of the off-axis electrode 12 in the x direction and the y direction, thereby forming a non-axisymmetric electric field to continuously deflect and scan the charged particle beam in the x direction and the y direction.It is worth mentioning that in the embodiment, the charged particle beam includes an electron beam and an ion beam. The incident-side electrode 11, the focusing electrode 13, the off-axis electrode 12, and the exit-side electrode 14 can be provided in any size and any shape, such as a thin film electrode, an electrode plate, and an electrode cylinder, wherein the thin film electrode is very thin and the thickness is negligible; the electrode plate has a certain thickness; the thickness of the electrode cylinder is much greater than the aperture; in the embodiment, the electrode plate is preferred, and the electrode plate is taken as an example for explanation, and the following will not be repeated.

[0032] The embodiment of the application provides an off-axis electrostatic deflector for a charged particle beam, a through hole 3 is arranged at the center of the electrode, the charged particle beam can be transmitted between coaxially arranged electrodes, a channel is provided for subsequent deflection and scanning of the charged particle beam, potentials of the incident-side electrode 11, the focusing electrode 13, the off-axis electrode 12, and the exit-side electrode 14 are fixed, the off-axis electrode 12 is controlled to move by the shifter, thereby forming a non-axisymmetric electric field to deflect and scan the charged particle beam, and the shifter controls the off-axis electrode 12 to move to change the distribution of the non-axisymmetric electric field, the charged particle beam is deflected and scanned in a deflection electric field that is not completely perpendicular to the optical axis direction, and the defocusing problem of the charged particle beam caused by the vertical electric field can be weakened; in addition, the voltage does not need to be changed in the deflection and scanning process, and the defocusing problem of the charged particle beam caused by voltage ripples due to voltage change can be weakened, thereby improving the deflection accuracy of the charged particle beam.

[0033] In a preferred embodiment, if two off-axis electrodes 12 are provided, the off-axis electrodes 12 include: a first off-axis electrode 12a and a second off-axis electrode 12b; the first off-axis electrode 12a and the second off-axis electrode 12b are coaxially arranged in parallel, and the focusing electrode 13 is coaxially arranged in parallel between the first off-axis electrode 12a and the second off-axis electrode 12b. The first off-axis electrode 12a is mechanically connected to a displacer 2, which is used to control the movement of the first off-axis electrode 12a in a first direction (equivalent to the x-direction) perpendicular to the preset optical axis a (equivalent to the z-direction), thereby deflecting the charged particle beam in the first direction. The second off-axis electrode 12b is mechanically connected to the displacer 2, which is used to control the movement of the second off-axis electrode 12b in a second direction (equivalent to the y-direction) perpendicular to the preset optical axis a and perpendicular to the first direction, thereby shifting the charged particle beam in the second direction. The distance that the first off-axis electrode 12a moves along the first direction is less than or equal to a preset first distance value, wherein the preset first distance value is set based on the aperture of the through-hole 3 of the first off-axis electrode 12a. The distance that the second off-axis electrode 12b moves along the second direction is less than or equal to a preset second distance value, wherein the preset second distance value is set based on the aperture of the through-hole 3 of the second off-axis electrode 12b. If the first off-axis electrode 12a moves, the second off-axis electrode 12b is fixed. The potential of the first off-axis electrode 12a and the potential of the second off-axis electrode 12b are set to be the same. The incident-side electrode 11, the first off-axis electrode 12a, and the focusing electrode 13 form a first electric field region AR1, which is used to control the deflection of the charged particle beam along the first direction.

[0034] A preferred embodiment of the present invention can be seen in Figure 2 , Figure 2 A schematic diagram of the module structure of an off-axis electrostatic deflector for a charged particle beam provided in one embodiment of the present invention Figure Two ;like Figure 2As shown, the off-axis electrostatic deflector is composed of five electrodes, which are coaxially and parallelly arranged from top to bottom in the order of the incident-side electrode 11, the first off-axis electrode 12a, the focusing electrode 13, the second off-axis electrode 12b, and the exit-side electrode 14. The first off-axis electrode 12a and the second off-axis electrode 12b are movable. The movable direction of the first off-axis electrode 12a is a first direction perpendicular to the preset optical axis a, which is the x direction in this embodiment. The first direction distance x0 at which the first off-axis electrode 12a is movable is less than or equal to a preset first distance value, which is one-tenth of the aperture of the through hole 3. The movable direction of the second off-axis electrode 12b is a second direction perpendicular to the preset optical axis a and perpendicular to the first direction, which is the y direction in this embodiment. The second direction distance y0 at which the second off-axis electrode 12b is movable is less than or equal to a preset second distance value, which is one-tenth of the aperture of the through hole 3. Since the through holes of the electrodes are uniform in this embodiment, the preset first distance value and the preset second distance value are the same in this embodiment. The incident-side electrode 11, the focusing electrode 13, and the exit-side electrode 14 are fixedly arranged and have fixed potentials. The incident-side electrode 11 and the exit-side electrode 14 have the same potential, which is denoted as a first potential V1. The first off-axis electrode 12a and the second off-axis electrode 12b have the same potential, which is denoted as a second potential V2. The potential of the focusing electrode 13 is denoted as a third potential V3. The first potential V1, the second potential V2, and the third potential V3 are all different. In this embodiment, the first potential V1, the second potential V2, and the third potential V3 are all adjustable. By adjusting the potentials of the electrodes, the focal length of the charged particle beam is adjusted. Before the first off-axis electrode 12a and the second off-axis electrode 12b start to move, the first potential V1, the second potential V2, and the third potential V3 can be set. After the first off-axis electrode 12a and the second off-axis electrode 12b start to move, the first potential V1, the second potential V2, and the third potential V3 remain unchanged. Finally, the displacer 2 is mechanically connected to the first off-axis electrode 12a to control the movement of the first off-axis electrode 12a in the first direction. At this time, the incident-side electrode 11, the first off-axis electrode 12a, and the focusing electrode 13 form a non-axisymmetric electric field, i.e., a first electric field region AR1. The first electric field region AR1 is used to control the deflection of the charged particle beam in the first direction, so that the charged particle beam is continuously deflected and scanned in the first direction. It is worth mentioning that the ratio of the third potential V3 to the second potential V2 should be not less than 0.95 and not greater than 1.05, so as to reduce the influence of the first electric field region AR1 on the focusing electric field AR0, which is composed of the incident-side electrode 11, the focusing electrode 13, and the exit-side electrode 14 and their corresponding potentials, and is used to focus the charged particle beam. The first electric field region AR1 is Figure 2 represented by the area of the dashed oval passing through the three electrode pieces; and the focusing electric field AR0 is Figure 2 represented by the area of the dashed oval passing through the five electrode pieces.

[0035] Another interpretation of the preferred solution, if the off-axis electrode 12 is provided as two, the off-axis electrode 12 comprises: a first off-axis electrode 12a and a second off-axis electrode 12b; the first off-axis electrode 12a and the second off-axis electrode 12b are coaxially parallel, and the focusing electrode 13 is coaxially parallel between the first off-axis electrode 12a and the second off-axis electrode 12b. The first off-axis electrode 12a is mechanically connected with the displacer 2, and the displacer 2 is used to control the first off-axis electrode 12a to move along a first direction perpendicular to the preset optical axis a, so as to deflect the charged particle beam along the first direction. The second off-axis electrode 12b is mechanically connected with the displacer 2, and the displacer 2 is used to control the second off-axis electrode 12b to move along a second direction perpendicular to the preset optical axis a and the first direction, so as to move the charged particle beam along the second direction. The distance of the first off-axis electrode 12a moving along the first direction is less than or equal to a preset first distance value, wherein the preset first distance value is set according to the aperture of the through hole 3 of the first off-axis electrode 12a. The distance of the second off-axis electrode 12b moving along the second direction is less than or equal to a preset second distance value, wherein the preset second distance value is set according to the aperture of the through hole 3 of the second off-axis electrode 12b. If the second off-axis electrode 12b moves, the first off-axis electrode 12a is fixedly arranged; the potential of the first off-axis electrode 12a and the potential of the second off-axis electrode 12b are set to be the same; see Figure 3 , the focusing electrode 13, the second off-axis electrode 12b and the exit side electrode 14 form a second electric field region AR2, and the second electric field region AR2 is used to control the charged particle beam to deviate along the second direction, wherein the second electric field region AR2 is Figure 3 represented by the dashed oval line passing through the three electrode pieces.

[0036] An implementation manner of the preferred solution, see Figure 3 , Figure 3 A schematic structural diagram of a module for an off-axis electrostatic deflector of a charged particle beam provided for an embodiment of the present application Figure Three ; as Figure 3As shown, the off-axis electrostatic deflector is composed of five electrodes, which are arranged coaxially and in parallel from top to bottom in the order of the incident-side electrode 11, the first off-axis electrode 12a, the focusing electrode 13, the second off-axis electrode 12b, and the exit-side electrode 14. The first off-axis electrode 12a and the second off-axis electrode 12b are movable, the movable direction of the first off-axis electrode 12a is a first direction perpendicular to the preset optical axis a, which is the x direction in this embodiment, and the first direction distance x0 of the movable first off-axis electrode 12a is less than or equal to a preset first distance value, which is one-tenth of the aperture of the through hole 3. The movable direction of the second off-axis electrode 12b is a second direction perpendicular to the preset optical axis a and perpendicular to the first direction, which is the y direction in this embodiment, and the second direction distance y0 of the movable second off-axis electrode 12b is less than or equal to a preset second distance value, which is one-tenth of the aperture of the through hole 3. Since the through holes of the electrodes are uniform in this embodiment, the preset first distance value and the preset second distance value are the same in this embodiment. The incident-side electrode 11, the focusing electrode 13, and the exit-side electrode 14 are fixedly arranged and have fixed potentials, the incident-side electrode 11 and the exit-side electrode 14 have the same first potential V1, the first off-axis electrode 12a and the second off-axis electrode 12b have the same second potential V2, the potential of the focusing electrode 13 is a third potential V3, and the first potential V1, the second potential V2, and the third potential V3 are all different. In this embodiment, the first potential V1, the second potential V2, and the third potential V3 are all adjustable, the size of the potential of each electrode is adjusted to further adjust the focal length of the charged particle beam, the first potential V1, the second potential V2, and the third potential V3 can be set before the first off-axis electrode 12a and the second off-axis electrode 12b start to move, and the first potential V1, the second potential V2, and the third potential V3 remain unchanged after the first off-axis electrode 12a and the second off-axis electrode 12b start to move. Finally, the displacer 2 is mechanically connected to the second off-axis electrode 12b to control the movement of the second off-axis electrode 12b in the second direction, at this time the focusing electrode 13, the second off-axis electrode 12b, and the exit-side electrode 14 form a non-axisymmetric electric field, i.e. a second electric field region AR2, which is used to control the charged particle beam to deviate in the second direction, so that the charged particle beam continuously deflects and scans in the second direction. It is worth mentioning that the ratio of the third potential V3 to the second potential V2 should be not less than 0.95 and not more than 1.05, so as to reduce the influence of the second electric field region AR2 on the focusing electric field AR0, which is composed of the incident-side electrode 11, the focusing electrode 13, and the exit-side electrode 14 and their corresponding potentials, and is used to focus the charged particle beam. In addition, the first off-axis electrode 12a and the second off-axis electrode 12b can be moved simultaneously to deflect and scan the charged particle beam to any position on the plane to realize plane scanning, if only one of the first off-axis electrode 12a and the second off-axis electrode 12b is moved, then linear scanning in a single direction can be realized.

[0037] In the above scheme, the off-axis electrostatic deflector is provided with two off-axis electrodes 12, which are respectively arranged on the two sides of the focusing electrode 13 coaxially and in parallel, so that the first off-axis electrode 12a deflects the charged particle beam in the first direction perpendicular to the preset optical axis a, and the second off-axis electrode 12b deflects the charged particle beam in the second direction perpendicular to the preset optical axis a and the first direction. The two off-axis electrodes 12 are arranged to move in different directions, thereby deflecting and scanning the charged particle beam in different directions. The movement distance of the first off-axis electrode 12a is limited to be less than or equal to a preset first distance value according to the through hole 3 of the first off-axis electrode 12a, and the movement distance of the second off-axis electrode 12b is limited to be less than or equal to a preset second distance value according to the through hole 3 of the second off-axis electrode 12b, so that the charged particle beam can pass through the off-axis electrode 12. Thus, it is ensured that the charged particle beam can be deflected and scanned simultaneously in the subsequent process. When the first off-axis electrode 12a is moved, the second off-axis electrode 12b is fixed, so that the incident side electrode 11, the first off-axis electrode 12a and the focusing electrode 13 form a first electric field region AR1, and the charged particle beam is deflected and scanned in the first direction. When the second off-axis electrode 12b is moved, the first off-axis electrode 12a is fixed, so that the focusing electrode 13, the first off-axis electrode 12a and the exit side electrode 14 form a second electric field region AR2, and the charged particle beam is deflected and scanned in the second direction. Only the movement of a single off-axis electrode 12 effectively prevents the deflection direction of the charged particle beam from being confused, and the displacement of the off-axis electrode controlled by the shifter changes the distribution of the non-axisymmetric electric field, so that the charged particle beam can be deflected and scanned in the deflection electric field which is not completely perpendicular to the optical axis direction, and the defocusing problem of the charged particle beam caused by the vertical electric field can be weakened. In addition, the voltage does not need to be changed during the deflection and scanning process, so that the defocusing problem of the charged particle beam caused by the voltage ripple due to the change of the voltage can be weakened, thereby improving the deflection accuracy of the charged particle beam.

[0038] In another preferred scheme, the off-axis electrode 12 is provided as one, and the off-axis electrode 12 is mechanically connected with the shifter 2, which is used to control the first off-axis electrode 12a to move in the first direction or the second direction, so that the charged particle beam is deflected in the first direction or the second direction. Referring to Figure 4 , if the off-axis electrode 12 moves in the first direction, the focusing electrode 13 and the off-axis electrode 12 form a third electric field region AR3, which is used to control the charged particle beam to deflect in the first direction.

[0039] In an implementation manner of a preferred scheme, referring to Figure 4 , Figure 4 A module structure diagram of an off-axis electrostatic deflector for a charged particle beam is provided for an embodiment of the present application Figure Four ; as Figure 4As shown, the off-axis electrostatic deflector is composed of 5 electrodes, wherein one off-axis electrode 12 is arranged and two focusing electrodes 13 are arranged, the focusing electrodes 13 include: a first focusing electrode 13a and a second focusing electrode 13b, which are coaxially and parallelly arranged from top to bottom in the order of the incident side electrode 11, the first focusing electrode 13a, the off-axis electrode 12, the second focusing electrode 13b and the exit side electrode 14. The off-axis electrode 12 is movable, the movable direction of the off-axis electrode 12 is a first direction perpendicular to the preset optical axis a, which is the x direction in this embodiment, and the first direction distance x0 of the movable direction of the off-axis electrode 12 is less than or equal to a preset first distance value, which is one tenth of the aperture of the through hole 3; the movable direction of the off-axis electrode 12 is a second direction perpendicular to the preset optical axis a and perpendicular to the first direction, which is the y direction in this embodiment, and the second direction distance y0 of the movable direction of the off-axis electrode 12 is less than or equal to a preset second distance value, which is one tenth of the aperture of the through hole 3, since the apertures of the through holes of the electrodes arranged in this embodiment are consistent, the preset first distance value and the preset second distance value are the same in this embodiment. The incident side electrode 11, the first focusing electrode 13a, the second focusing electrode 13b and the exit side electrode 14 are fixedly arranged and have fixed potentials, the incident side electrode 11 and the exit side electrode 14 have the same potential, which is the fourth potential V4, the off-axis electrode 12 has a potential, which is the fifth potential V5, the first focusing electrode 13a and the second focusing electrode 13b have the same potential, which is the sixth potential V6, and the fourth potential V4, the fifth potential V5 and the sixth potential V6 are all different. In this embodiment, the fourth potential V4, the fifth potential V5 and the sixth potential V6 are all adjustable, the focal length of the charged particle beam can be adjusted by adjusting the potential of each electrode, the fourth potential V4, the fifth potential V5 and the sixth potential V6 can be set before the off-axis electrode 12 starts to move, and the fourth potential V4, the fifth potential V5 and the sixth potential V6 remain unchanged after the off-axis electrode 12 starts to move. The displacer 2 is mechanically connected with the off-axis electrode 12 to control the movement of the off-axis electrode 12 in the first direction, at this time the first focusing electrode 13a, the off-axis electrode 12 and the second focusing electrode 13b form a non-axisymmetric electric field, i.e. the third electric field region AR3, which is used to control the deflection of the charged particle beam in the first direction, so that the charged particle beam continuously deflects and scans in the first direction. It is worth mentioning that the ratio of the third potential V3 to the second potential V2 should be not less than 0.95 and not greater than 1.05, so as to reduce the influence of the third electric field region AR3 on the focusing electric field AR0, which is composed of the incident side electrode 11, the focusing electrodes 13 and the exit side electrode 14 and their corresponding potentials, and is used to focus the charged particle beam, wherein the third electric field region AR3 is Figure 4 represented by the area of the dashed oval passing through three electrode pieces; the focusing electric field AR0 is Figure 4 represented by the area of the dashed oval passing through five electrode pieces.

[0040] Another interpretation of the preferred embodiment, the off-axis electrode 12 is provided as one, the off-axis electrode 12 is mechanically connected with the displacer 2, the displacer 2 is used to control the first off-axis electrode 12a to move along the first direction or the second direction, so as to deflect the charged particle beam along the first direction or the second direction. Referring to Figure 5 , if the off-axis electrode 12 moves along the second direction, the focusing electrode 13 and the off-axis electrode 12 form a fourth electric field region AR4, and the fourth electric field region AR4 is used to control the charged particle beam to deflect along the second direction.

[0041] An implementation manner of a preferred embodiment, referring to Figure 5 , Figure 5 A schematic structural diagram of a module structure of an off-axis electrostatic deflector for a charged particle beam provided for an embodiment of the present application Figure Five ; as Figure 5As shown, the off-axis electrostatic deflector is composed of 5 electrodes, wherein one off-axis electrode 12 is arranged and two focusing electrodes 13 are arranged, the focusing electrodes 13 include: a first focusing electrode 13a and a second focusing electrode 13b, which are coaxially and parallelly arranged from top to bottom in the order of the incident side electrode 11, the first focusing electrode 13a, the off-axis electrode 12, the second focusing electrode 13b and the exit side electrode 14. The off-axis electrode 12 is movable, the movable direction of the off-axis electrode 12 is a first direction perpendicular to the preset optical axis a, which is the x direction in this embodiment, and the first direction distance x0 of the movable direction of the off-axis electrode 12 is less than or equal to a preset first distance value, which is one tenth of the aperture of the through hole 3; the movable direction of the off-axis electrode 12 is a second direction perpendicular to the preset optical axis a and perpendicular to the first direction, which is the y direction in this embodiment, and the second direction distance y0 of the movable direction of the off-axis electrode 12 is less than or equal to a preset second distance value, which is one tenth of the aperture of the through hole 3, since the apertures of the through holes of the electrodes arranged in this embodiment are consistent, the preset first distance value and the preset second distance value are the same in this embodiment. The incident side electrode 11, the first focusing electrode 13a, the second focusing electrode 13b and the exit side electrode 14 are fixedly arranged and have fixed potentials, the incident side electrode 11 and the exit side electrode 14 have the same potential, which is the fourth potential V4, the off-axis electrode 12 has a potential, which is the fifth potential V5, the first focusing electrode 13a and the second focusing electrode 13b have the same potential, which is the sixth potential V6, and the fourth potential V4, the fifth potential V5 and the sixth potential V6 are all different. In this embodiment, the fourth potential V4, the fifth potential V5 and the sixth potential V6 are all adjustable, the focal length of the charged particle beam can be adjusted by adjusting the potential of each electrode, the fourth potential V4, the fifth potential V5 and the sixth potential V6 can be set before the off-axis electrode 12 starts to move, and the fourth potential V4, the fifth potential V5 and the sixth potential V6 remain unchanged after the off-axis electrode 12 starts to move. The displacer 2 is mechanically connected with the off-axis electrode 12 to control the movement of the off-axis electrode 12 in the second direction, at this time the first focusing electrode 13a, the off-axis electrode 12 and the second focusing electrode 13b form a non-axisymmetric electric field, i.e. the fourth electric field region AR4, which is used to control the charged particle beam to deviate in the second direction, so that the charged particle beam continuously deflects and scans in the second direction. It is worth mentioning that the ratio of the third potential V3 to the second potential V2 should be not less than 0.95 and not greater than 1.05, so as to reduce the influence of the fourth electric field region AR4 on the focusing electric field AR0, which is composed of the incident side electrode 11, the focusing electrodes 13 and the exit side electrode 14 and their corresponding potentials, and is used to focus the charged particle beam, wherein the fourth electric field region AR4 is Figure 5 represented by the area of the dashed oval passing through three electrode pieces; the focusing electric field AR0 is Figure 5 represented by the area of the dashed oval passing through five electrode pieces.

[0042] In the above scheme, the off-axis electrostatic deflector is provided with only one off-axis electrode 12, and the focusing electrode 13 is coaxially parallel to and adjacent to the off-axis electrode 12, so that when the off-axis electrode 12 moves in different directions, a deflection electric field is generated, causing the charged ion beam to be deflected and scanned in the deflection electric field. When the off-axis electrode 12 moves along a first direction, the focusing electrode and the off-axis electrode 12 form a third electric field region AR3, which controls the deflection scanning of the charged particle beam in the first direction; when the off-axis electrode 12 moves along a second direction, the focusing electrode 13 and the off-axis electrode 12 form a fourth electric field region AR4, which controls the deflection scanning of the charged particle beam in the second direction. A shifter is used to control the movement of the off-axis electrode to change the distribution of the non-axisymmetric electric field, so that the charged particle beam is deflected and scanned in a deflection electric field that is not completely perpendicular to the optical axis direction, which can weaken the defocusing problem of the charged particle beam caused by the vertical electric field. In addition, there is no need to change the voltage during the deflection scanning process, which can weaken the defocusing problem of the charged particle beam caused by voltage ripples generated by voltage changes, thereby improving the deflection accuracy of the charged particle beam.

[0043] Example 2

[0044] In order to adapt to the application scenario of miniaturization, an off-axis electrostatic deflector for a charged particle beam proposed in an embodiment of the present invention is improved. An off-axis electrostatic deflector for a charged particle beam consisting of five electrodes arranged from top to bottom, namely, an incident side electrode 11, a first off-axis electrode 12a, a focusing electrode 13, a second off-axis electrode 12b, and an exit side electrode 14, is used as an example for explanation. Figure 6 , Figure 6 Schematic diagram of an improved module structure of an off-axis electrostatic deflector for a charged particle beam provided by an embodiment of the present invention Figure One ;like Figure 6 As shown, when the displacer 2 is removed and the charged particle beam needs to be deflected in the x-direction, the incident-side electrode 11, the focusing electrode 13, the second off-axis electrode 12b, and the exit-side electrode 14 are arranged parallel and coaxially, and the first off-axis electrode 12a is fixedly arranged at a distance x0 in the first direction. At this time, by continuously adjusting the voltage value of the first off-axis electrode 12a, a non-axisymmetric electric field is formed between the incident-side electrode 11, the first off-axis electrode 12a, and the focusing electrode 13, i.e., the fifth electric field region AR5. Continuous deflection and scanning of the charged particle beam in the x-direction is achieved through the fifth electric field region AR5, wherein the fifth electric field region AR5 is Figure 6 The dotted ellipse passing through the three electrodes represents the area; the focused electric field AR0 is Figure 6 The dotted ellipse passing through the five electrodes represents the area; similarly, see Figure 7 , Figure 7 Schematic diagram of an improved module structure of an off-axis electrostatic deflector for a charged particle beam provided by an embodiment of the present invention Figure Two ;likeFigure 7 As shown, when the displacement device 2 is removed and the charged particle beam needs to be deflected along the y direction, the incident side electrode 11, the first off-axis electrode 12a, the focusing electrode 13, and the exit side electrode 14 are arranged in parallel and coaxially, and the second off-axis electrode 12b is fixedly arranged at a position with a second direction distance y0. At this time, by continuously adjusting the voltage value of the second off-axis electrode 12b, the focusing electrode 13, the second off-axis electrode 12b, and the exit side electrode 14 form a non-axisymmetric electric field, i.e., a sixth electric field region AR6, and further, the charged particle beam is continuously deflected and scanned along the y direction through the sixth electric field region AR6, wherein the sixth electric field region AR6 is Figure 7 The region represented by the dashed oval line passing through the three electrode pieces.

[0045] Through the above improvement, the off-axis electrode 12 is fixedly arranged to be different from the preset optical axis, and the off-axis electrode 12 is adjusted to form a non-axisymmetric electric field (deflection electric field) to deflect and scan the charged particle beam. Therefore, by arranging the off-axis electrode 12 to deviate from the preset optical axis and adjusting the voltage of the off-axis electrode 12 to change the distribution of the non-axisymmetric electric field (equivalent to the deflection electric field), the charged particle beam can be deflected and scanned in the deflection electric field which is not completely perpendicular to the optical axis direction, and the defocus problem of the charged particle beam caused by the vertical electric field can be weakened.

[0046] Embodiment 3

[0047] Referring to Figure 8 , Figure 8 A step flowchart of a deflection scanning method for a charged particle beam provided by an embodiment of the present application. As shown in Figure 8 A deflection scanning method for a charged particle beam, comprising steps S1 to S3, and the specific steps are as follows:

[0048] S1: receiving a charged particle beam incident from an incident side electrode along a preset optical axis;

[0049] S2: controlling the displacement device to move the off-axis electrode to generate a non-axisymmetric electric field;

[0050] S3: based on the non-axisymmetric electric field, controlling the charged particle beam to continuously deflect and scan.

[0051] The embodiment of the present application proposes a deflection scanning method for a charged particle beam, the potential of an incident side electrode, a focusing electrode, an off-axis electrode and an exit side electrode is fixed, the off-axis electrode is controlled to move by a shifter, so as to form a non-axisymmetric electric field (deflection electric field) to deflect the charged particle beam, and the distribution of the non-axisymmetric electric field is changed by controlling the off-axis electrode to move by the shifter, so as to realize deflection scanning of the charged particle beam in the deflection electric field which is not completely perpendicular to the optical axis direction, and the defocus problem of the charged particle beam caused by the vertical electric field can be weakened; in addition, the voltage does not need to be changed during the deflection scanning process, and the defocus problem of the charged particle beam caused by voltage ripples due to voltage changes can be weakened, so as to improve the deflection accuracy of the charged particle beam.

[0052] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

[0053] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0054] In addition, the terms "first", "second" are only for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

Claims

1. An off-axis electrostatic deflector for a charged particle beam, characterized in that include: An incident side electrode, a focusing electrode, at least one off-axis electrode, an exit side electrode and a displacer; the incident side electrode, the focusing electrode, the off-axis electrode and the exit side electrode are all provided with a through hole, and the through hole is used to pass the charged particle beam; The incident-side electrode, the focusing electrode, the off-axis electrode, and the exit-side electrode are coaxially and parallelly arranged in a preset arrangement sequence, wherein the incident-side electrode is fixedly arranged at the first position in the preset arrangement sequence, and the exit-side electrode is fixedly arranged at the last position in the preset arrangement sequence; The potential of the incident-side electrode, the potential of the focusing electrode, and the potential of the off-axis electrode are different from each other and are fixed, and the potential of the output-side electrode is the same as the potential of the incident-side electrode and is fixed; The off-axis electrode is mechanically connected to a displacer, and the displacer is used to control the displacement of the off-axis electrode to form a non-axisymmetric electric field to enable the charged particle beam to continuously deflect and scan.

2. An off-axis electrostatic deflector for a charged particle beam according to claim 1, characterized in that: The through hole is provided at the center of the incident-side electrode, the focusing electrode, the off-axis electrode, and the exit-side electrode, and the through hole can be provided in any rotationally symmetrical shape.

3. An off-axis electrostatic deflector for a charged particle beam according to claim 2, characterized in that: If the number of the off-axis electrodes is two, the off-axis electrodes include: a first off-axis electrode and a second off-axis electrode; The first off-axis electrode and the second off-axis electrode are coaxially arranged in parallel, and the focusing electrode is coaxially arranged in parallel between the first off-axis electrode and the second off-axis electrode; The first off-axis electrode is mechanically connected to the displacer, and the displacer is used to control the first off-axis electrode to move along a first direction perpendicular to a preset optical axis, so as to deflect the charged particle beam along the first direction; The second off-axis electrode is mechanically connected to a displacer, and the displacer is used to control the second off-axis electrode to move along a second direction perpendicular to the preset optical axis and perpendicular to the first direction, so that the charged particle beam moves along the second direction.

4. An off-axis electrostatic deflector for a charged particle beam according to claim 3, characterized in that: The distance that the first off-axis electrode moves along the first direction is less than or equal to a preset first distance value, wherein the preset first distance value is set according to the aperture of the through hole of the first off-axis electrode; The distance that the second off-axis electrode moves along the second direction is less than or equal to a preset second distance value, wherein the preset second distance value is set according to the aperture of the through hole of the second off-axis electrode.

5. An off-axis electrostatic deflector for a charged particle beam according to claim 4, characterized in that: The potential of the first off-axis electrode and the potential of the second off-axis electrode are set to be the same; If the first off-axis electrode moves, the incident-side electrode, the first off-axis electrode, and the focusing electrode form a first electric field region, and the first electric field region is used to control the charged particle beam to deflect along the first direction.

6. An off-axis electrostatic deflector for a charged particle beam according to claim 5, characterized in that: If the second off-axis electrode moves, the focusing electrode, the second off-axis electrode and the exit-side electrode form a second electric field region, and the second electric field region is used to control the charged particle beam to deflect along the second direction.

7. An off-axis electrostatic deflector for a charged particle beam according to claim 6, characterized in that: If the off-axis electrode is set as one, the focusing electrode is coaxially parallel to and adjacent to the off-axis electrode, and the off-axis electrode is mechanically connected to a displacer, which is used to control the first off-axis electrode to move along the first direction or the second direction, so that the charged particle beam is deflected along the first direction or the second direction.

8. An off-axis electrostatic deflector for a charged particle beam according to claim 7, characterized in that: If the off-axis electrode moves along the first direction, the focusing electrode and the off-axis electrode form a third electric field region, and the third electric field region is used to control the charged particle beam to deflect along the first direction.

9. An off-axis electrostatic deflector for a charged particle beam according to claim 8, characterized in that: If the off-axis electrode moves along the second direction, the focusing electrode and the off-axis electrode form a fourth electric field region, and the fourth electric field region is used to control the charged particle beam to deflect along the second direction.

10. A deflection scanning method for a charged particle beam, characterized in that: An off-axis electrostatic deflector for a charged particle beam as claimed in any one of claims 1 to 9, wherein the deflection scanning method for the charged particle beam comprises: receiving a charged particle beam incident from an incident-side electrode along a preset optical axis; Controlling the shifter to move the off-axis electrode to generate a non-axisymmetric electric field; Based on the non-axisymmetric electric field, the charged particle beam is controlled to continuously deflect and scan.

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