Multi-beam charged particle source with alignment method

Abstract

The present invention relates to an apparatus and a method for generating a plurality of substantially collimated charged particle sub-beams. The apparatus includes a charged particle source for generating a divergent charged particle beam, a beam splitter for splitting the charged particle beam into an array of charged particle sub-beams, a deflector array including an array of deflectors, the array of deflectors including one deflector for each charged particle sub-beam of the array of charged particle sub-beams, wherein the deflector array is configured to substantially collimate the array of divergent charged particle sub-beams. The apparatus further includes a beam manipulation device configured to generate an electric field and / or a magnetic field at least in a region between the charged particle source and the deflector array. The apparatus includes a central axis, and the beam manipulation device is configured to generate an electric field and / or a magnetic field substantially parallel to and substantially perpendicular to the central axis.

Description

[0001] Embodiments of the present invention relate to an apparatus and method for generating multiple charged particle sub-beams. Background Art

[0002] Charged particle beams are used in various systems, such as lithography, inspection, and imaging systems. Some of these systems use a single charged particle source to generate a charged particle beam, which is then split into multiple charged particle sub-beams.

[0003] Specifically, US 2004 / 0232349A1 describes an apparatus for generating multiple charged particle sub-beams, including a charged particle source for generating a divergent charged particle beam, a converging device for refracting the divergent charged particle beam, and a lens array including multiple lenses. The lens array is disposed between the charged particle source and the converging device.

[0004] For applications where the size of the array of multiple charged particle sub-beams at the collimator plane is large, it becomes impractical to use a single electron lens for collimation. As described in US 2004 / 0232349A1, a deflector array can be used as a converging device, especially for collimating a divergent charged particle beam. The deflector array includes deflectors for each charged particle sub-beam to deflect the sub-beam. Summary of the Invention

[0005] A disadvantage of known apparatuses for generating multiple charged particle beams is that the position of the array of charged particle sub-beams needs to be precisely aligned with the position of collimation equipment, such as an array of deflectors of a deflector array.

[0006] Incorrect alignment with the array of deflectors will result in, in particular, not every sub-beam passing through the center of the corresponding deflector of the array of deflectors, and thus incorrect alignment may generate a deviation from the desired deflection of each sub-beam, or even cause sub-beam blockage when the sub-beam misses the aperture of the corresponding deflector.

[0007] An object of the present invention is to at least partially solve at least one of the above-mentioned defects, at least partially, and / or provide an alternative apparatus for generating multiple charged particle sub-beams, which allows alignment of the charged particle sub-beams relative to a deflector array.

[0008] According to a first aspect, there is provided an apparatus for generating multiple charged particle sub-beams, the apparatus comprising:

[0009] a charged particle source for generating a divergent charged particle beam,

[0010] a beam splitter for splitting the charged particle beam into an array of charged particle sub-beams,

[0011] A deflector array, comprising an array of deflectors, the array of deflectors comprising one deflector for each charged particle beam of an array of charged particle beams, wherein the deflector array is configured to at least substantially collimate an array of diverging charged particle beams, and a beam manipulation device configured to generate an electric field and / or a magnetic field at least in a region between a charged particle source and the deflector array, wherein the device comprises a central axis, wherein the charged particle source, the centre of the beam splitter and the centre of the deflector array are arranged on the central axis, and wherein the beam manipulation device is configured to generate:

[0012] An electric field that is substantially parallel and / or perpendicular to the central axis, and / or

[0013] A magnetic field that is substantially parallel and / or perpendicular to the central axis.

[0014] In the device according to the invention, the beam manipulation device allows the manipulation of the charged particle beams in order to optimize the alignment of the charged particle beams on the deflector array. Due to the presence of the manipulation device, the mechanical alignment of the elements of the device for generating a plurality of charged particle beams may be less accurate. More importantly, the alignment of the charged particle beams can be adjusted during the operation of the device, for example to correct any thermal expansion of the elements of the device and / or to correct any drift.

[0015] When considering a Cartesian coordinate system of the device with a Z-axis parallel to the central axis and X- and Y-axes in a plane perpendicular to the central axis, the electric and / or magnetic fields generated by the beam manipulation device can be assigned as follows:

[0016] Using a magnetic field extending along the Y-axis and / or an electric field extending along the X-axis, the array of charged particle beams can be moved in the direction along the X-axis. By carefully controlling the magnitude of the magnetic field and / or the electric field, the actual position of the array of charged particle beams on the deflector array along the X-axis can be controlled in order to align the array of charged particle beams with the deflector array.

[0017] Using a magnetic field extending along the X-axis and / or an electric field extending along the Y-axis, the array of charged particle beams can be moved in the direction along the Y-axis. By carefully controlling the magnitude of the magnetic field and / or the electric field, the actual position of the array of charged particle beams on the deflector array along the Y-axis can be controlled in order to align the array of charged particle beams with the deflector array.

[0018] Using a magnetic field that at least partially extends along the Z-axis, an array of charged particle beams can be rotated about the Z-axis. By carefully controlling the magnitude of the magnetic field, the actual position of the array of charged particle beams around the Z-axis on the deflector array can be controlled so that the array of charged particle beams is aligned with the deflector array. It should be noted that such a magnetic field is typically generated using coils of conductive wires arranged in the XY plane, and preferably, the central axis of the coil is arranged on the Z-axis. Since the magnetic field of such a coil bends around the conductive wires of the coil, the magnetic fields before and after the coil are not exactly parallel to the Z-axis, as shown in the view along the Z-axis. Therefore, such a magnetic field also provides a lens effect. This lens effect can be compensated for by controlling the divergence of the charged particle beam from the source, for example, by adjusting the voltage on the charged particle source electrode, such as the voltage on the extractor electrode.

[0019] Additionally, by using an electrostatic field and / or a magnetic field (which is configured to provide a change in the field in a direction parallel to the central axis), the spacing between the sub-beams of the array of charged particle beams can be adjusted.

[0020] In a preferred embodiment, the beam manipulation device is configured to combine several of these magnetic and / or electric fields by combining one or more of the embodiments described below. This allows for the adjustment of the deviation of the charged particle beam array in multiple directions / rotational alignments. The specific arrangement of the beam manipulation device depends in particular on the specific use of the device and / or the alignment accuracy required in the specific application in which the device is used to generate multiple charged particle beams.

[0021] In one embodiment, the beam manipulation device includes one or more first coils for generating a magnetic field in a first direction substantially perpendicular to the central axis. The device according to this embodiment provides a relatively simple beam manipulation device that allows for the adjustment of the alignment of the array of charged particle beams in cases where the deviation and / or drift is mainly in the direction perpendicular to the central axis and the first direction.

[0022] In one embodiment, in addition to the one or more first coils, the beam manipulation device further includes one or more second coils for generating a magnetic field in a second direction substantially perpendicular to the central axis and substantially perpendicular to the first direction. The device according to this embodiment provides a beam manipulation device that allows for the adjustment of the alignment of the array of charged particle beams in a plane perpendicular to the central axis, particularly in directions along two orthogonal directions, such as along the X-axis and Y-axis described above.

[0023] In one embodiment, the beam manipulation device includes a third coil for generating a magnetic field in a direction at least partially along and substantially parallel to the central axis. The device according to this embodiment provides a beam manipulation device that allows for the adjustment of the alignment of the array of charged particle beams relative to rotation about the central axis.

[0024] Note that the magnetic field generated by the third coil can also provide a change in the spacing between the sub-beams of an array of charged particle beams. Thus, in one embodiment, the third coil is a first third coil, and the beam steering device further includes a second third coil configured to provide a magnetic field having a magnetic field variation in a direction parallel to the central axis, wherein the first coil and the second coil are configured such that, preferably, the spacing between the sub-beams of the array of charged particle beams is adjusted without substantially adjusting the rotation about the central axis. By using two third coils, the combined effects of rotation and spacing variation can be at least partially separated.

[0025] In one embodiment, the beam steering device includes one or more first electrodes for generating an electrostatic field in a first direction substantially perpendicular to the central axis. The device according to this embodiment provides a relatively simple beam steering device that allows adjustment of the alignment of an array of charged particle beams in cases where deviations and / or drifts are mainly in a direction perpendicular to the central axis and parallel to the first direction.

[0026] Note that an electrostatic field in a first direction substantially perpendicular to the path along which the charged particles move provides a force to the charged particles substantially parallel to the first direction, while a magnetic field in a first direction substantially perpendicular to the path along which the charged particles move provides a force to the charged particles substantially perpendicular to the first direction.

[0027] In one embodiment, in addition to one or more first coils, the beam steering device further includes one or more second electrodes for generating a magnetic field in a second direction substantially perpendicular to the central axis and substantially perpendicular to the first direction. The device according to this embodiment provides a beam steering device that allows adjustment of the alignment of an array of charged particle beams in a plane perpendicular to the central axis, particularly in directions along the X and Y axes as described above. In one embodiment, the beam steering device includes one or more third electrodes for generating an electrostatic field in a direction along and substantially parallel to the central axis, wherein the one or more third electrodes are configured to provide an electrostatic field having a variation in a direction parallel to the central axis in order to adjust the spacing between the sub-beams of the array of charged particle beams.

[0028] Note that the latter embodiment can advantageously be combined with an embodiment in which the beam steering device includes a third coil for generating a magnetic field in a direction at least partially along and substantially parallel to the central axis, as described above. As already indicated above, the magnetic field of the third coil can provide rotation of the array of charged particle beams about the central axis, as well as a change in the spacing between the sub-beams of the array of charged particle beams. By combining one or more third electrodes with the coil, the combined effects of rotation and spacing change of the third coil can be at least partially separated.

[0029] In addition to, or as an alternative to, the generation of a magnetic field and / or an electric field as described above, the manipulation device may also be configured to generate a multipole field, such as a quadrupole field or an octupole field. By using, for example, a quadrupole magnetic field and / or an electric field, an array of charged particle beams may be, for example, more closely bunched together in a first direction and spread out in a second direction, where the second direction may be substantially perpendicular to the first direction. Thus, the spacing between the charged particle beams in the first direction may be reduced, while the spacing between the charged particle beams in the second direction may be increased. One or more of the embodiments described below may be used to generate one or more of these magnetic and / or electric quadrupole fields:

[0030] In one embodiment, the beam manipulation device includes one or more fourth coils for generating a quadrupole magnetic field in a plane substantially perpendicular to the central axis. In one embodiment, the beam manipulation device includes four fourth coils, where two coils are arranged on opposite sides of the central axis and have a first common coil axis, and the other two coils are arranged on opposite sides of the central axis and have a second common coil axis perpendicular to the first common coil axis, where the first and second common coil axes are arranged in a plane substantially perpendicular to the central axis. Preferably, the four fourth coils are arranged at substantially the same distance from the central axis.

[0031] In another embodiment, the beam manipulation device includes two sets of fourth coils, each configured to generate a quadrupole magnetic field in a plane substantially perpendicular to the central axis, where the first common coil axis of the first set is arranged at an acute angle with respect to the first common coil axis of the second set. In one embodiment, the angle between the first common coil axis of the first set and the first common coil axis of the second set is substantially 45 degrees.

[0032] In one embodiment, the beam manipulation device includes one or more fourth electrodes for generating a quadrupole electrostatic field in a plane substantially perpendicular to the central axis. In one embodiment, the beam manipulation device includes four fourth electrodes, where two coils are arranged on opposite sides of the central axis and on a first common electrode axis, and the other two coils are arranged on opposite sides of the central axis and on a second common electrode axis perpendicular to the first common electrode axis, where the first and second common electrode axes are arranged in a plane substantially perpendicular to the central axis. Preferably, the four fourth electrodes are arranged at substantially the same distance from the central axis.

[0033] In another embodiment, the beam manipulation device includes two sets of fourth electrodes, each configured to generate a quadrupole electrostatic field in a plane substantially perpendicular to the central axis, where the first common electrode axis of the first set is arranged at an acute angle with respect to the first common electrode axis of the second set. In one embodiment, the angle between the first common electrode axis of the first set and the first common electrode axis of the second set is substantially 45 degrees.

[0034] Additionally or alternatively, in said another embodiment, the beam manipulation device includes a set of fourth coils configured to generate a quadrupole magnetic field in a plane substantially perpendicular to the central axis, wherein a first common coil axis of the set of fourth coils is arranged to be substantially parallel to a first common electrode axis of the set of fourth electrodes.

[0035] Note that in another embodiment, the beam manipulation device may further include another coil and / or electrode for generating a higher-order multipole magnetic field and / or an electrostatic field, which is arranged between the charged particle source and the deflector array or between the charged particle source and the collimator lens.

[0036] In one embodiment, the device further includes a control system for the beam manipulation device, wherein the control system is configured to adjust the electric field and / or magnetic field based on signals from sensors, wherein the sensors are configured to measure the deviation of one or more charged particle sub-beams in the array of charged particle sub-beams from the desired alignment. Thus, the device for generating a plurality of charged particle sub-beams can be actively controlled to maintain the desired alignment of the charged particle sub-beams. In one embodiment, the sensors are arranged at or near the deflector array or the collimator lens. In one embodiment, the beam splitter includes a lens array, which includes a plurality of lenses, and each charged particle sub-beam has one lens.

[0037] In an alternative embodiment, the device includes a lens array, which includes a plurality of lenses, and each charged particle sub-beam has one lens, wherein the lens array is arranged between the beam splitter and the deflector array.

[0038] In one embodiment, the device includes a collimator lens and a focusing lens. The collimator lens is arranged between the beam splitter and the charged particle source, and the focusing lens is arranged between the beam splitter and the deflector array, wherein the focusing lens is configured to provide a common intersection of a plurality of charged particle sub-beams between the focusing lens and the deflector array. Preferably, the focusing lens and the deflector array are configured to provide a beam expander.

[0039] In an alternative embodiment, the device includes a collimator lens arranged between the beam splitter and the charged particle source, and a diverging lens arranged between the beam splitter and the deflector array. Preferably, the diverging lens and the deflector array are configured to provide a beam expander. In this embodiment, a common intersection of a plurality of charged particle sub-beams can be avoided.

[0040] By using a collimator, it can be ensured that the charged particle beam impinging on the beam splitter is a substantially collimated charged particle beam. This further collimator at least substantially prevents problems that occur when splitting a divergent charged particle beam with a substantially planar orifice plate or electrode plate, where the incident beam does not pass through the orifice plate of the electrode plate perpendicular to the plane of the planar orifice plate or electrode plate, as described, for example, in US2004 / 0232349A1. According to a second aspect, the present invention provides a method for generating a plurality of charged particle sub-beams, the method comprising the following steps:

[0041] Generating a divergent charged particle beam using a charged particle source,

[0042] Splitting the charged particle beam into an array of charged particle sub-beams using a beam splitter,

[0043] Using an array of deflectors to substantially deflect each charged particle sub-beam in the array of charged particle sub-beams, the array of deflectors comprising an array of deflectors, the array of deflectors comprising one deflector for each charged particle sub-beam, wherein the array of deflectors is configured to at least substantially collimate the array of divergent charged particle sub-beams, and

[0044] Using a beam manipulation device for aligning the array of charged particle sub-beams relative to the array of deflectors to generate an electric field and / or a magnetic field at least in the region between the charged particle source and the array of deflectors,

[0045] Wherein the device comprises a central axis, wherein the charged particle source, the center of the beam splitter, and the center of the array of deflectors are arranged on the central axis, and wherein the beam manipulation device generates:

[0046] An electric field substantially parallel and / or perpendicular to the central axis, and / or

[0047] A magnetic field substantially parallel and / or perpendicular to the central axis.

[0048] In the method of the present invention, the beam manipulation device allows manipulation of the charged particle beam in order to optimize the alignment of the charged particle sub-beams on the array of deflectors. Due to the presence of the manipulation device, the mechanical alignment of the elements of the device for generating a plurality of charged particle sub-beams may be less accurate. More importantly, the alignment of the charged particle sub-beams can be adjusted during the operation of the device, for example to correct for any thermal expansion of the elements of the device and / or to correct for any drift. In particular, an electric field and / or a magnetic field is generated in order to adjust the alignment of the array of charged particle sub-beams by providing one or more of the following:

[0049] Deflection of the array of charged particle sub-beams in a first direction substantially perpendicular to the central axis,

[0050] Deflection of the array of charged particle sub-beams in a second direction substantially perpendicular to the first direction and the central axis,

[0051] Rotation of an array of charged particle beams about a central axis

[0052] Elongation in a first direction substantially perpendicular to the central axis and contraction in a second direction substantially perpendicular to the first direction and the central axis of the array of charged particle beams, and

[0053] Elongation or contraction of the array of charged particle beams in a radial direction relative to the central axis (and thus changing the spacing between the beams of the array of charged particle beams).

[0054] In one embodiment, the device further includes a control system for the beam manipulation device, wherein the control system adjusts the electric field and / or magnetic field based on signals from sensors, wherein the sensors determine deviations from a desired alignment of one or more of the charged particle beams of the array of charged particle beams. Thus, actively control the device for generating a plurality of charged particle beams to maintain the desired alignment of the charged particle beams. In one embodiment, the sensors are arranged at or near the deflector array or the collimator lens.

[0055] In one embodiment, the beam splitter includes a lens array including a plurality of lenses, the lenses including one lens for each charged particle beam, wherein each charged particle beam of the array of charged particle beams is refracted by a lens of the lens array.

[0056] In one embodiment, the device includes a lens array including a plurality of lenses, the plurality of lenses including one lens for each charged particle beam, wherein the lens array is arranged between the beam splitter and the deflector array, and wherein each charged particle beam of the array of charged particle beams is refracted by a lens of the lens array.

[0057] The various aspects and features described and illustrated in the specification can be applied separately where possible. These separate aspects, especially those described in the appended dependent claims, can be the subject of divisional patent applications.

[0058] Brief Description of the Drawings

[0059] The present invention will be described based on exemplary embodiments shown in the drawings, wherein:

[0060] Figure 1A and 2A Schematically shows an example of a device for generating a plurality of charged particle beams, the device having a beam manipulation device configured to generate a magnetic field substantially perpendicular to the central axis

[0061] Figure 1B Schematically shows Figure 1A The device in a plane perpendicular to the central axis

[0062] Figure 2B which schematically shows a device for combining in a plane perpendicular to the central axis Figure 1A and 2A a beam manipulation device

[0063] Figure 3A which schematically shows another example of a device for generating a plurality of charged particle sub - beams, the device having a beam manipulation device configured to generate a magnetic field at least partially parallel to the central axis

[0064] Figure 3B which schematically shows Figure 3A a device in a plane perpendicular to the central axis

[0065] Figure 4A which schematically shows another example of a device for generating a plurality of charged particle sub - beams, the device having a beam manipulation device configured to generate an electric field substantially perpendicular to the central axis

[0066] Figure 4B which schematically shows Figure 4A a device in a plane perpendicular to the central axis

[0067] Figure 5A which schematically shows another example of a device for generating a plurality of charged particle sub - beams, the device having a beam manipulation device configured to generate a quadrupole magnetic field or an electrostatic field substantially perpendicular to the central axis

[0068] Figure 5B which schematically shows Figure 5A a first example of the device in a plane perpendicular to the central axis, wherein coils are arranged on the X - axis and the Y - axis to generate a quadrupole magnetic field

[0069] Figure 5C which schematically shows Figure 5A a second example of the device in a plane perpendicular to the central axis, wherein coils are arranged in the XY - plane and rotated clockwise by more than 45 degrees relative to the position of the coils in Figure 5B and

[0070] Figure 5D which schematically shows Figure 5A a third example of the device in a plane perpendicular to the central axis, wherein electrodes are arranged on the X - axis and the Y - axis to generate a quadrupole electrostatic field, and

[0071] Figure 5E which schematically shows Figure 5A a fourth example of the device in a plane perpendicular to the central axis, wherein electrodes are arranged in the XY - plane and relative toFigure 5D The position of the electrodes in

[0072] INVENTION DESCRIPTION

[0073] Note that the beam manipulation device according to the present invention is preferably configured to combine a plurality of magnetic fields and / or electric fields. This allows adjustment of the deviation of a charged particle beam in multiple directions / rotational alignments. To more clearly describe examples of beam manipulation devices that allow adjustment of sub-beam alignment, these different examples are described separately below, but it should be understood that in the beam manipulation device according to the present invention, one or more of the embodiments described below are combined.

[0074] FIG. 1 shows a first example of an apparatus 10 for generating a plurality of charged particle sub-beams 16. The apparatus 10 includes a charged particle source 11 having an extraction electrode 19 for generating a divergent charged particle beam 12. The divergent charged particle beam 12 is directed onto a collimating lens 13, and subsequently at least substantially collimated charged particle beam 12 is directed onto a beam splitter 14 for splitting the charged particle beam 12 into an array 16 of charged particle sub-beams. In this example, the beam splitter 14 includes an array of lenses configured to focus each charged particle sub-beam 16. Additionally, the lens array is combined with an electrode 141 to provide a diverging lens for generating a divergent array of charged particle sub-beams 16. The divergent charged particle sub-beams 16 are directed to a deflector array 15, which includes an array of deflectors, each charged particle sub-beam 16 having one deflector. The apparatus 10 includes a central axis CA, where the charged particle source 11, the center of the beam splitter 14, and the center of the deflector array 15 are arranged on the central axis CA. The deflector array 15 is configured to substantially deflect each charged particle sub-beam 16 to provide an array of substantially collimated charged particle sub-beams 16. Note that the diverging lens provided by the beam splitter 14 and the electrode 141 and the deflector array 15 together form a beam expander. In the example shown in FIG. 1, the lens array is configured to substantially focus each charged particle sub-beam 16 at the plane of the deflector array 15.

[0075] The position of the array of divergent charged particle sub-beams 16 needs to be precisely aligned with the position of the array of deflectors of the deflector array 15. To assist in alignment and / or adjustment of alignment, the apparatus 10 of the present invention includes a beam manipulation device that includes a first coil 17 and a second coil 18, the first coil 17 and the second coil 18 being arranged on opposite sides of the central axis CA. The coils 17, 18 are configured to generate a magnetic field BX in the region between the charged particle source 11 and the deflector array 15, particularly in the region between the beam splitter 14 and the deflector array 15.

[0076] As schematically indicated in FIG. 1, the magnetic field Bx extends substantially in a direction parallel to the X-axis and substantially perpendicular to the central axis CA. In the case where the charged particle beam 16 comprises positively charged particles and the magnetic field Bx extends in the positive X-axis direction, the magnetic field BX will generate a force on the positively charged particles that causes the positively charged particles to move in the positive Y-axis direction, as Figure 1B schematically indicated therein.

[0077] In the figure, the open circles represent the positions of the charged particle beams when the magnetic or electrostatic fields of the manipulation device are off, while the filled circles represent the positions of the charged particle beams when the magnetic or electrostatic fields of the manipulation device are on.

[0078] It should be noted that the combination of the beam splitter 14 and the electrode 141 is configured to generate an electrostatic field in a direction along and substantially parallel to the central axis and is thus configured to operate as one or more of the third electrodes identified above. The beam splitter 14 and the electrode 14 can be arranged to provide a varying electrostatic field in a direction parallel to the central axis in order to adjust the spacing between the sub-beams of the array of charged particle beams, particularly at the deflector array 15.

[0079] Figure 2A A first alternative example of an apparatus 10' for generating a plurality of charged particle beams 16' is shown. The apparatus 10' includes a charged particle source 11 having an extraction electrode 19' for generating a divergent charged particle beam 12'. The divergent charged particle beam 12' is directed onto a beam splitter 14' for splitting the divergent charged particle beam 12' into an array of charged particle beams 16'. The charged particle beams 16' are directed to a deflector array 15' that includes an array of deflectors, the array of deflectors including one deflector for each charged particle beam 16'. The apparatus 10' includes a central axis CA, wherein the center of the charged particle source 11', the center of the beam splitter 14', and the center of the deflector array 15' are arranged on the central axis CA. The deflector array 15' is configured to substantially deflect each charged particle beam 16' towards the central axis CA, where the deflection is configured to increase with the distance from the central axis CA. In particular, the deflector array 15' is configured to substantially deflect each charged particle beam 16' so as to provide a substantially collimated array of charged particle beams 16'. In the Figure 2A example shown, the beam splitter 14' includes a lens array 14' that is configured to substantially focus each charged particle beam 16' at the plane of the deflector array 15'. For example, such a system is also described in US2004 / 0232349A1, particularly in FIG. 7 thereof.

[0080] Similarly, the positions of the charged particle beam 16' arrays need to be precisely aligned with the positions of the deflectors of the deflector array 15'. To assist in alignment and / or adjustment of alignment, the device 10' of the present invention includes a beam steering device that includes a first coil 17' and a second coil 18', with the first coil 17' and the second coil 18' arranged on opposite sides of the central axis CA. The coils 17', 18' are configured to generate a magnetic field BY in the region between the charged particle source 11' and the deflector array 15', particularly in the region between the beam splitter 14' and the deflector array 15'. In the case where the charged particle beam 16' includes positively charged particles and the magnetic field BY extends in the positive Y-axis direction, the magnetic field BY will exert a force on the positively charged particles, causing the positively charged particles to move in the negative X-axis direction.

[0081] The deflection amount ΔX depends particularly on the intensity of the magnetic field BY. Therefore, by controlling the intensity of the magnetic field BY, the deflection amount ΔX can be controlled, so that the arrays 16' of the charged particle beams are precisely aligned with the openings in the deflector array 15'.

[0082] It should be noted that negatively charged particles will move in the opposite direction of the positive X-axis. As Figure 1A schematically indicated, the coils 17, 18 can be configured to provide a magnetic field BX in a direction parallel to the X-axis and substantially perpendicular to the central axis CA. As Figure 2A schematically indicated, the coils 17', 18' can be configured to provide a magnetic field BY in a direction parallel to the Y-axis and substantially perpendicular to the central axis CA. By combining Figure 1A the example of Figure 2A and the beam steering device of the example of Figure 2B the alignment of the sub-beams 16' can be adjusted in the X and Y directions, as Figure 3A schematically indicated. In a second example of the device 20 of the present invention as shown in

[0083] The apparatus 20 further includes beam manipulation equipment, which includes a coil 27 arranged around a central axis CA. Preferably, the central axis CA and the central axis of the coil 27 are substantially coincident. The coil 27 is configured to generate a magnetic field B that curls around the coil 27, and is configured to generate a magnetic field BZ at least in the region within the coil 27 and in the region between the charged particle source 21 and the deflector array 25, especially in the region between the beam splitter 23 and the deflector array 25. In use, the magnetic field BZ will generate a force on the charged particles, which provides a rotation ΔRZ of the array 24 of charged particle beams around the central axis CA, as Figure 3B schematically indicated. The amount of rotation ΔRZ depends especially on the strength of the magnetic field BZ. Thus, by controlling the strength of the magnetic field BZ, the amount of rotation ΔRZ can be controlled, so that the array 26 of charged particle beams is precisely aligned with the openings in the deflector array 25.

[0084] It should be noted that the direction of rotation of the array of charged particle beams with negatively charged particles is opposite to the direction of rotation of the array of charged particle beams with positively charged particles, as Figure 3B shown.

[0085] It should also be noted that the magnetic field on one side of the coil 27 curls towards the central axis CA, while the magnetic field on the other side of the coil 27 curls away from the central axis CA. Thus, viewed from the angle along the Z-axis, the magnetic fields before and after the coil 27 are not exactly parallel to the Z-axis. Such a magnetic field provides an additional lens effect. This lens effect can be compensated by controlling the divergence of the charged particle beam 22 from the source 21, for example by adjusting the voltage on the electrodes of the charged particle source 21, such as the voltage on the extractor electrode 29.

[0086] In a third example of the apparatus 30 of the present invention as shown in Figure 4A , the apparatus 30 includes a charged particle source 31, which has an extraction electrode 39 for generating a divergent charged particle beam 32, a beam splitter 33 for splitting the divergent charged particle beam 32 into an array of divergent charged particle sub-beams 34, and a deflector array 35, which includes an array of deflectors, and each deflector of the array of deflectors corresponds to one charged particle beam 34. The charged particle source 31, the center of the beam splitter 33, and the center of the deflector array 35 are arranged on the central axis CA. The deflector array 35 is configured to deflect each charged particle beam 34 substantially towards the central axis CA, where the deflection is preferably configured to provide an array of substantially collimated charged particle sub-beams 36. Preferably, the beam splitter 33 includes a lens array, which is configured to focus each divergent charged particle sub-beam 34 substantially at the plane of the deflector array 35.

[0087] To assist in alignment and / or adjustment of alignment, the apparatus 30 of this example includes a beam manipulation device that includes a first electrode 37 and a second electrode 38, with the first electrode 37 and the second electrode 38 disposed on opposite sides of the central axis CA. The electrodes 37, 38 are configured to generate an electric field EX in the region between the charged particle source 31 and the deflector array 35, particularly in the region between the beam splitter 33 and the deflector array 35.

[0088] As Figure 4A schematically indicated, the electrodes 37, 38 can be configured to provide the electric field EX in a direction parallel to the X-axis and substantially perpendicular to the central axis CA. In the case where the charged particle sub-beam 34 includes positively charged particles and the electric field EX extends in the positive X-axis direction, the electric field EX will generate a force on the positively charged particles that causes the positively charged particles to move in the positive X-axis direction, as Figure 4B schematically indicated. The deflection amount ΔX depends in particular on the intensity of the electric field EX. Thus, by controlling the intensity of the electric field EX, the deflection amount ΔX can be controlled, thereby precisely aligning the array 36 of charged particle sub-beams with the openings in the deflector array 35.

[0089] Note that negatively charged particles will move in the opposite direction of the negative X-axis.

[0090] Further note that, in a similar manner, the apparatus 30 can also be equipped with electrodes that generate an electric field in the Y-direction (e.g., in the positive Y-axis direction). In the case where the charged particle sub-beam 34 includes positively charged particles, the electric field extending in the positive Y-axis direction will generate a force on the positively charged particles that causes the positively charged particles to move in the positive Y-axis direction.

[0091] In as Figure 5AIn a fourth example of the device 40 of the present invention shown in [figure reference], the device 40 includes a charged particle source 41 for generating a divergent charged particle beam 42, a beam splitter 43 for splitting the divergent charged particle beam 42 into an array of divergent charged particle sub-beams 44, and a deflector array 45 that includes an array of deflectors, where the array of deflectors includes one deflector for each charged particle sub-beam 44, and the charged particle source 41, the center of the beam splitter 43, and the center of the deflector array 45 are arranged on a central axis CA. The deflector array 45 is configured to deflect each charged particle sub-beam 44 substantially towards the central axis CA, where the deflection is preferably configured to provide an array of substantially collimated charged particle beams 46. Preferably, the beam splitter 43 includes an array of lenses that is configured to focus each divergent charged particle sub-beam 44 substantially at the plane of the deflector array 45. To assist in alignment and / or adjustment of the alignment, the device 40 of this example includes a beam manipulation device that includes a quadrupole deflector 47. In this particular example, the quadrupole deflector 47 includes a set of coils, in particular coils 48, 49, 50, 51, which are arranged around the central axis CA and are located in a plane perpendicular to the central axis CA, in particular all at the same distance from the central axis CA, as Figure 5B schematically shown in [figure reference]. The coils 48, 49, 50, 51 are configured to generate a quadrupole magnetic field in the region between the charged particle source 41 and the deflector array 45, in particular in the region between the beam splitter 43 and the deflector array 45.

[0092] As Figure 5B schematically shown in [figure reference], the coils 48, 49, 50, 51 can be configured such that each coil provides a magnetic field B in a direction towards or away from the array 46 of charged particles. The combined magnetic field B of the coils 48, 49, 50, 51 will generate:

[0093] a. A force F1 on positive charge particles between the first and second coils 48, 49 that pushes the positive charge particles towards a direction substantially parallel to the diagonal in the +X, +Y directions,

[0094] b. A force F2 on positive charge particles between the second and third coils 49, 50 that pushes the positive charge particles towards a direction substantially parallel to the diagonal in the -X, +Y directions,

[0095] c. A force F3 on positive charge particles between the third and fourth coils 50, 51 that pushes the positive charge particles towards a direction substantially parallel to the diagonal in the -X, -Y directions, and

[0096] d. A force F4 on positive charge particles between the fourth and first coils 51, 48 that pushes the positive charge particles towards a direction substantially parallel to the diagonal in the +X, -Y directions.

[0097] Thus, the quadrupole deflector 47 compresses the array in a direction parallel to the diagonal in the +X, +Y directions (along the F1, F3 directions), and extends the array in a direction parallel to the diagonal in the -X, Y directions (along the F2, F4 directions), as Figure 5B schematically indicated. The amounts of extension and compression depend in particular on the strength of the magnetic field B. Thus, by controlling the strength of the magnetic field B, the amounts of extension and compression can be controlled so that the array 46 of charged particle beams is precisely aligned with the openings in the deflector array 45. It should be noted that when the coils 48, 49, 50, 51 are driven to provide a magnetic field B in the direction opposite to the magnetic field Figure 5B shown, the forces acting on the charged particles will also act in a direction opposite to the Figure 5B forces shown.

[0098] It should be further noted that negatively charged particles will move in the opposite direction, so that the extension will be parallel to the F1, F3 directions and the compression will be parallel to the F2, F4 directions.

[0099] Additionally or alternatively, the quadrupole deflector 47 includes a second set of coils, in particular coils 48', 49', 50', 51' arranged around the central axis CA, in particular all the coils being at the same distance from the central axis CA, as Figure 5C schematically shown. The coils 48’, 49’, 50’, 51’ are configured to generate a quadrupole magnetic field in the region between the charged particle source 41 and the deflector array 45, in particular in the region between the beam splitter 43 and the deflector array 45.

[0100] As Figure 5C schematically shown, the coils 48’, 49’, 50’, 51’ can be configured so that each coil provides a magnetic field B in a direction towards or away from the array 46 of charged particles. The combined magnetic field B of the coils 48’, 49’, 50’, 51’ will generate:

[0101] a. A force F1 on the positively charged particles between the first and second coils 48’, 49’ that pushes the positively charged particles in a direction substantially parallel to the

[0102] +X direction,

[0103] b. A force F2’ on the positively charged particles between the second and third coils 49’, 50’ that pushes the positively charged particles in a direction substantially parallel to the +Y direction,

[0104] c. A force F3’ on the positively charged particles between the third and fourth coils 50’, 51’ that pushes the positively charged particles in a direction substantially parallel to the -X direction, and

[0105] d. The force F4' on the positively charged particles between the fourth and first coils 51', 48', which pushes the positively charged particles in a direction substantially parallel to the -Y direction.

[0106] Thus, the quadrupole deflector 47 provides compression of the array of charged particle beams 46 in a direction parallel to the X-axis and provides extension of the array in a direction parallel to the Y-axis, as Figure 5C schematically shown. The amounts of extension and compression depend in particular on the strength of the magnetic field B. Thus, by controlling the strength of the magnetic field B, the amounts of extension and compression can be controlled so that the array of charged particle beams 46 is precisely aligned with the openings in the deflector array 45.

[0107] Note that when the coils 48', 49', 50', 51' are driven to provide a magnetic field B in a direction opposite to the magnetic field shown in Figure 5C the force acting on the charged particle beam 46 will also act in a direction opposite to the force shown in Figure 5C the figure.

[0108] Further note that a beam of negatively charged particles will move in a direction opposite to the example in Figure 5C so that the extension will be parallel to the X-axis and the compression will be parallel to the Y-axis.

[0109] Additionally or alternatively, the quadrupole deflector 47 includes a fourth set of electrodes, in particular electrodes 48'', 49'', 50'', 51'' arranged around the central axis CA, in particular all the electrodes being at the same distance from the central axis CA, as Figure 5D schematically shown. The coils 48'', 49'', 50'', 51'' are configured to generate a quadrupole electrostatic field in the region between the charged particle source 41 and the deflector array 45, in particular in the region between the beam splitter 43 and the deflector array 45.

[0110] a. As Figure 5D schematically shown, the coils 48'', 49'', 50'', 51'' can be configured so that each coil provides an electrostatic field E in a direction towards or away from the array 46'' of charged particles. When the electrodes are supplied with a potential as shown in Figure 5D the combined electrostatic field E of the electrodes 48'', 49'', 50'', 51'' will generate: a force F1'' that pulls negatively charged particles towards the electrode 48'' in a direction substantially parallel to the -Y direction,

[0111] b. A force

[0112] F2'' that pushes negatively charged particles towards the electrode 49'' in a direction substantially parallel to the +X direction

[0113] c. A force that pulls negatively charged particles towards the electrode 50'' in a direction substantially parallel to the +Y direction

[0114] "F3", and

[0115] d. A force F4" that pushes the negatively charged particles near the electrode 51" in a direction substantially parallel to the -X direction.

[0116] Therefore, the quadrupole deflector 47 provides compression of the array of negatively charged particle beams 46" in a direction parallel to the X-axis and provides extension of the array in a direction parallel to the Y-axis, as Figure 5D schematically shown. The amounts of extension and compression depend particularly on the intensity of the electrostatic field E. Therefore, by controlling the intensity of the electrostatic field E, the amounts of extension and compression can be controlled, so that the array 46 of charged particle beams is precisely aligned with the openings in the deflector array 45.

[0117] Note that when the coils 48", 49", 50", 51" are driven to provide an electrostatic field E in a direction opposite to the electrostatic field shown in Figure 5D , the forces acting on the negatively charged particle beam will also act in a direction opposite to the forces shown in Figure 5D .

[0118] Further note that when using the same arrangement of the electrostatic field E as shown in Figure 5D , the positively charged particle beam will move in a direction opposite to the example shown in Figure 5D , so that the extension will be parallel to the X-axis and the compression will be parallel to the Y-axis.

[0119] Additionally or alternatively, the quadrupole deflector 47 includes a fourth group of electrodes, particularly electrodes 48'", 49'", 50'", 51'" arranged around the central axis CA, particularly with all electrodes at the same distance from the central axis CA, as Figure 5E schematically shown. The electrodes 48'", 49'", 50'", 51'" are arranged in the XY plane and are rotated 45 degrees clockwise with respect to the positions of the electrodes 48", 49", 50", 51" in Figure 5D . When the potentials shown in Figure 5E are applied to the electrodes 48'", 49'", 50'", 51'", the quadrupole deflector 47 provides array compression in the directions of the +X, +Y directions (parallel to the directions of F1'" and F3'") and provides array extension in the directions of the -X, Y directions (parallel to the directions of F2'" and F4'"). The amounts of extension and compression depend particularly on the intensity of the electrostatic field E. Therefore, by controlling the intensity of the electrostatic field E, the amounts of extension and compression can be controlled, so that the array 46'" of charged particle beams is precisely aligned with the openings in the deflector array 45. Note that Figure 5B , 5C, exemplary embodiments of 5D and 5E can be used alone or in combination in the quadrupole deflector 47 according to the present invention.

[0120] It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not intended to limit the scope of the present invention. From the above discussion, many variations not covered by the scope of the present invention will become apparent to those skilled in the art.

[0121] As described above, the manipulation device according to the present invention preferably incorporates one or more of the above examples in order to provide the desired possibilities for correcting the trajectory of a charged particle beam, in particular for aligning a charged particle beam on a deflector array.

[0122] In addition, Figure 3A , 4A , the manipulation devices 27, 38, and 47 in 5A, 5B, 5C, 5D, and 5E can also be used and / or combined in the beam expander of FIG. 1.

[0123] In summary, the present invention relates to an apparatus and method for generating a plurality of substantially collimated charged particle sub-beams. The apparatus includes a charged particle source for generating a divergent charged particle beam, a beam splitter for splitting the charged particle beam into an array of charged particle sub-beams, a deflector array including an array of deflectors, the array of deflectors including one deflector for each charged particle sub-beam of the array of charged particle sub-beams, wherein the deflector array is configured to substantially collimate the array of divergent charged particle sub-beams. The apparatus further includes a beam manipulation device configured to generate an electric field and / or a magnetic field at least in the region between the charged particle source and the deflector array. The apparatus includes a central axis, and the beam manipulation device is configured to generate an electric field and / or a magnetic field that is substantially parallel to and substantially perpendicular to the central axis.

Claims

1. A device for generating a plurality of charged particle sub-beams, comprising: A charged particle source for generating a divergent charged particle beam, A beam splitter for splitting the charged particle beam into an array of charged particle sub-beams, A deflector array including an array of deflectors, the array of deflectors including one deflector for each charged particle sub-beam of the array of charged particle sub-beams, wherein the deflector array is configured to collimate the array of divergent charged particle sub-beams, and A beam manipulation device configured to generate an electric field and / or a magnetic field at least in a region between the charged particle source and the deflector array, wherein the electric field and / or the magnetic field is configured to optimize the alignment of the charged particle sub-beams on the deflector array, Wherein the device includes a central axis, wherein the charged particle source, the center of the beam splitter, and the center of the deflector array are arranged on the central axis, and wherein the beam manipulation device is configured to generate: An electric field perpendicular to the central axis, and / or A magnetic field perpendicular to the central axis.

2. The device according to claim 1, characterized in that, The device further includes a control system for controlling the beam manipulation device, wherein the control system is configured to adjust the electric field and / or the magnetic field based on a signal from a sensor, wherein the sensor is configured to measure the deviation of one or more charged particle sub-beams in the array of charged particle sub-beams from a desired alignment.

3. The device according to claim 1 or 2, characterized in that, The beam manipulation device includes one or more first coils for generating a magnetic field in a first direction perpendicular to the central axis.

4. The device according to claim 3, characterized in that, The beam manipulation device includes one or more second coils for generating a magnetic field in a second direction perpendicular to the central axis and perpendicular to the first direction.

5. The device according to claim 1 or 2, characterized in that, The beam manipulation device includes a third coil for generating a magnetic field in a first direction along and parallel to the central axis.

6. The device according to claim 5, characterized in that, The third coil is a first third coil, wherein the beam manipulation device further includes a second third coil configured to provide a magnetic field having a magnetic field variation in a direction parallel to the central axis, wherein the first third coil and the second third coil are configured to adjust the spacing between the sub-beams of the array of charged particle sub-beams.

7. The device according to claim 6, wherein The first third coil and the second third coil are configured to adjust the spacing between the sub-beams of the array of charged particle sub-beams without adjusting around the central axis.

8. The device according to claim 1 or 2, characterized in that, The beam manipulation device includes one or more fourth coils for generating a quadrupole magnetic field in a plane perpendicular to the central axis.

9. The device according to claim 8, characterized in that, The beam manipulation device includes a set of four fourth coils, wherein two fourth coils are arranged on opposite sides of the central axis and have a first common coil axis, and wherein the other two fourth coils are arranged on opposite sides of the central axis and have a second common coil axis perpendicular to the first common coil axis, wherein the first and second common coil axes are arranged in a plane perpendicular to the central axis.

10. The device according to claim 9, characterized in that, The beam manipulation device includes two sets of fourth coils including a first set and a second set, each set of fourth coils being configured to generate a quadrupole magnetic field in a plane perpendicular to the central axis, wherein a first common coil axis of the first set is arranged at an acute angle with respect to a first common coil axis of the second set.

11. The device according to claim 10, characterized in that, The acute angle between the first common coil axis of the first set and the first common coil axis of the second set is 45 degrees.

12. The device according to claim 1 or 2, characterized in that, The beam manipulation device includes one or more first electrodes for generating an electrostatic field in a first direction perpendicular to the central axis.

13. The device according to claim 12, characterized in that, The beam manipulation device includes one or more second electrodes for generating an electrostatic field in a second direction perpendicular to the central axis and perpendicular to the first direction.

14. The device according to claim 1 or 2, characterized in that, The beam manipulation device includes one or more third electrodes for generating an electrostatic field in a direction along and parallel to the central axis, wherein the one or more third electrodes are configured to provide an electrostatic field that varies in the direction parallel to the central axis so as to adjust the spacing between the sub-beams of the array of charged particle sub-beams.

15. The device according to claim 1 or 2, characterized in that The beam manipulation device includes one or more fourth electrodes for generating a quadrupole electrostatic field in a plane perpendicular to the central axis.

16. The device according to claim 15, characterized in that, The beam manipulation device includes a set of four fourth electrodes, wherein two fourth electrodes are arranged on opposite sides of the central axis and on a first common electrode axis, and the other two fourth electrodes are arranged on opposite sides of the central axis and have a second common electrode axis perpendicular to the first common electrode axis, wherein the first and second common electrode axes are arranged in a plane perpendicular to the central axis.

17. The device according to claim 16, characterized in that, The beam manipulation device includes two sets of fourth electrodes including a first set and a second set, each set of fourth electrodes being configured to generate a quadrupole electrostatic field in a plane perpendicular to the central axis, wherein a first common electrode axis of the first set is arranged at an acute angle with respect to a first common electrode axis of the second set.

18. The device according to claim 17, characterized in that, The acute angle between the first common electrode axis of the first set and the first common electrode axis of the second set is 45 degrees.

19. The device according to claim 1 or 2, It is characterized in that The beam splitter includes a lens array, the lens array including a plurality of lenses, including one lens for each charged particle sub-beam, or wherein the device includes a lens array, the lens array including a plurality of lenses, including one lens for each charged particle sub-beam, wherein the lens array is arranged between the beam splitter and the deflector array or between the beam splitter and the collimating lens.

20. The device according to claim 1, characterized in that, The beam manipulation device includes: a set of at least two coils arranged on opposite sides of the central axis and having a common coil central axis, wherein the common coil central axis is arranged in a plane substantially perpendicular to the central axis, and / or a set of at least two electrodes arranged on opposite sides of the central axis and having a common electrode axis, wherein the common electrode axis is arranged in a plane substantially perpendicular to the central axis.

21. The device according to claim 1, characterized in that, The beam manipulation device is arranged in the array of divergent charged particle sub-beams.

22. A method for generating a plurality of charged particle sub-beams, comprising the steps of: A divergent charged particle beam is generated using a charged particle source, the charged particle beam is split into an array of charged particle sub-beams using a beam splitter, each charged particle sub-beam in the array of charged particle sub-beams is substantially deflected using an array of deflectors, the array of deflectors comprising an array of deflectors, the array of deflectors comprising one deflector for each charged particle sub-beam, wherein the array of deflectors is configured to collimate the array of divergent charged particle sub-beams, and a beam manipulation device for aligning the array of charged particle sub-beams relative to the array of deflectors of the array of deflectors is used to generate an electric field and / or a magnetic field at least in a region between the charged particle source and the array of deflectors, wherein the charged particle source, the center of the beam splitter, and the center of the array of deflectors are arranged on a central axis of the device, and wherein the beam manipulation device generates: an electric field perpendicular to the central axis, and / or a magnetic field perpendicular to the central axis.

23. The method according to claim 22, wherein The device further comprises a control system for the beam manipulation device, wherein the control system adjusts the electric field and / or the magnetic field based on a signal from a sensor, wherein the sensor is arranged to determine a deviation from a desired alignment.

24. The method according to claim 23, wherein The sensor is arranged at or near the array of deflectors or a collimator lens.

25. The method according to claim 22, 23 or 24, It is characterized in that the beam splitter comprises a lens array comprising a plurality of lenses, the plurality of lenses comprising one lens for each charged particle sub-beam, wherein each charged particle sub-beam of the array of charged particle sub-beams is refracted by a lens of the lens array, or wherein the device comprises a lens array comprising a plurality of lenses, the plurality of lenses comprising one lens for each charged particle sub-beam, wherein the lens array is arranged between the beam splitter and the array of deflectors or between the beam splitter and a collimator lens, and wherein each charged particle sub-beam of the array of charged particle sub-beams is refracted by a lens of the lens array.

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