Multi-beam inspection device

Abstract

An improved source conversion unit of a charged particle beam device is disclosed. The source conversion unit includes a first microstructure array, which includes a plurality of microstructures. The plurality of microstructures are grouped into one or more groups. Corresponding electrodes of the microstructures in a group are electrically connected and driven by a driver to affect a corresponding group of beam waves. The microstructures in a group can be monopole structures or multipole structures. The microstructures in a group have the same or substantially the same radial offset relative to the optical axis of the device. The microstructures in a group have the same or substantially the same orientation angle relative to their radial offset direction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 62 / 665,451, filed May 1, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments provided herein disclose a multi-beam inspection apparatus, and more particularly, disclose a multi-beam inspection apparatus including an improved source conversion unit. Background Art

[0004] When manufacturing semiconductor integrated circuit (IC) chips, pattern defects and / or uninvited particles (residues) inevitably appear on wafers and / or masks during the manufacturing process, thereby greatly reducing the yield rate. For example, for patterns with smaller critical feature sizes (which have been adopted to meet the increasingly higher performance requirements of IC chips), uninvited particles can be troublesome.

[0005] Pattern inspection tools with a single electron beam have been used to detect defects and / or uninvited particles. These tools typically employ a scanning electron microscope (SEM). In an SEM, a primary electron beam with relatively high energy is decelerated so as to land on a sample with a relatively low landing energy, and is focused to form a detection spot thereon. Due to this focused detection spot of the primary electrons, secondary electrons will be generated from the surface. By scanning the detection spot over the sample surface and collecting the secondary electrons, the pattern inspection tool can acquire an image of the sample surface. Summary of the invention

[0006] Embodiments of the present disclosure provide a multi-beam inspection device, and more specifically, provide a multi-beam inspection device including an improved source conversion unit. In some embodiments, a microstructure array including a first group of monopole structures is provided. The first group of monopole structures has a first radial offset relative to the central axis of the array, wherein the first radial offsets are equal or substantially equal. In addition, the first group of monopole structures includes corresponding electrodes electrically connected and driven by a first driver.

[0007] In some embodiments, a microstructure array is provided that includes a first set of multipolar structures. The first set of multipolar structures has a first radial offset and a first orientation angle relative to a central axis of the array, wherein the first radial offsets are equal or substantially equal, and the first orientation angles are equal or substantially equal. In addition, the first set of multipolar structures includes corresponding electrodes electrically connected and driven by a first driver.

[0008] In some embodiments, a source conversion unit in a charged particle device is provided. The source conversion unit includes a first microstructure array having a first group of multipole structures. The first group of multipole structures has a first radial offset and a first orientation angle relative to an optical axis of the device, wherein the first radial offsets are equal or substantially equal, and the first orientation angles are the same or substantially the same. In addition, the first group of multipole structures includes corresponding electrodes electrically connected and driven by a first driver associated with the first microstructure array. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other aspects of the present disclosure will become more apparent through the description of exemplary embodiments with reference to the accompanying drawings.

[0010] Figure 1 is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system according to an embodiment of the present disclosure.

[0011] Figure 2 The present invention is shown as an embodiment of the present invention. Figure 1 A schematic diagram of an exemplary multi-beam apparatus that is a portion of an exemplary electron beam inspection system.

[0012] Figure 3A is a schematic diagram of an exemplary multi-beam device, showing an embodiment of the present disclosure Figure 1 An exemplary configuration of a source switching unit of an exemplary electron beam inspection system.

[0013] Figure 3B and 3C Exemplary deflection characteristics with respect to corresponding radial directions are shown.

[0014] Figure 3D An exemplary multipole structure having a dipole configuration is shown.

[0015] Figure 3E An exemplary multipole structure having a quadrupole configuration is shown.

[0016] Figure 3F An exemplary multipole structure having an octupole configuration is shown.

[0017] Figure 4A and 4B is a schematic diagram showing an exemplary configuration of an array of multi-pole structures.

[0018] Figure 5A is a schematic diagram illustrating an exemplary configuration of an image forming element array according to an embodiment of the present disclosure.

[0019] Figure 5B is a schematic diagram illustrating an exemplary configuration of another image forming element array according to an embodiment of the present disclosure.

[0020] Figure 5Cis a schematic diagram showing an exemplary configuration including an image forming element array and an auxiliary micro deflector array according to an embodiment of the present disclosure.

[0021] Fig. 6A is a schematic diagram showing an exemplary configuration of a field curvature compensator array according to an embodiment of the present disclosure.

[0022] Figure 6B is a schematic diagram showing another exemplary configuration of a field curvature compensator array according to an embodiment of the present disclosure.

[0023] Figure 6C is a schematic diagram showing a portion of an exemplary configuration including a field curvature compensator array and an auxiliary microlens array according to an embodiment of the present disclosure.

[0024] Fig. 7A is a schematic diagram showing an exemplary configuration of an astigmatism compensator array according to an embodiment of the present disclosure.

[0025] Figure 7B is a schematic diagram showing another exemplary configuration of an astigmatism compensator array according to an embodiment of the present disclosure.

[0026] Figure 7C is a schematic diagram showing a portion of an exemplary configuration including an astigmatism compensator array and an auxiliary micro-stigmatizer array according to an embodiment of the present disclosure.

[0027] Fig. 8A is a schematic diagram showing an exemplary configuration of a field curvature compensator array including a portion of an astigmatism compensator array according to an embodiment of the present disclosure.

[0028] Figure 8B is a schematic diagram illustrating an exemplary configuration of an astigmatism compensator array including a portion of a field curvature compensator array according to an embodiment of the present disclosure.

[0029] Fig. 9 is a flow chart illustrating an exemplary method for controlling a driver associated with a microstructure according to an embodiment of the present disclosure.

[0030] Fig.10 is a flow chart illustrating an exemplary method for forming a microstructure array according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] Reference will now be made in detail to exemplary embodiments, examples of which are shown in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments set forth in the following description of exemplary embodiments are not intended to represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with various aspects of the present invention as described in the appended claims.

[0032] For the sake of clarity, the relative sizes of components in the drawings may be exaggerated. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences with respect to the various embodiments are described.

[0033] Without limiting the scope of protection, all descriptions and drawings of the embodiments will refer to electron beams by way of example. However, the embodiments are not intended to limit the present invention to specific charged particles.

[0034] Reference now Figure 1 , Figure 1 is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system according to an embodiment of the present disclosure. Figure 1 As shown, the charged particle beam inspection system 1 includes a main chamber 10 , a load / lock chamber 20 , an electron beam tool 100 , and an equipment front end module (EFEM) 30 . The electron beam tool 100 is located in the main chamber 10 .

[0035] The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b may, for example, accommodate a wafer front opening unified pod (FOUP) that accommodates wafers (e.g., semiconductor wafers or wafers made of other materials) or samples to be inspected (wafers and samples are collectively referred to as "wafers" hereinafter). One or more robot arms (not shown) in the EFEM 30 transport the wafers to the load / lock chamber 20.

[0036] The load / lock chamber 20 is connected to a load / lock vacuum pump system (not shown) that removes gas molecules in the load / lock chamber 20 to reach a first pressure lower than atmospheric pressure. After reaching the first pressure, one or more robot arms (not shown) transport the wafer from the load / lock chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pump system (not shown) that removes gas molecules in the main chamber 10 to reach a second pressure lower than the first pressure. After reaching the second pressure, the wafer is inspected by the electron beam tool 100.

[0037] The controller 109 is electrically connected to the electron beam tool 100. The controller 109 may be a computer configured to perform various controls of the EBI system 100. Figure 1 10 is shown as being outside the structure including the main chamber 10, the load / lock chamber 20 and the EFEM 30, but it should be understood that the controller 109 can be part of the structure. Although the present disclosure provides an example of a main chamber 10 housing an electron beam inspection system, it should be noted that aspects of the present disclosure in its broadest sense are not limited to a chamber housing an electron beam inspection system. Instead, it should be understood that the aforementioned principles can also be applied to other tools operating at a second pressure.

[0038] Reference now Figure 2 , Figure 2 The present invention is shown as an embodiment of the present invention. Figure 1 Schematic diagram of an exemplary multi-beam device 100 as a part of an exemplary electron beam inspection system. The electron beam tool 100 (also referred to herein as device 100) includes an electron source 101, a gun hole plate 171, a condenser lens 110, a source conversion unit 120, a main projection optical system 130, a sample 8 having a sample surface 7, a secondary imaging system 150, and an electron detection device 140M. The main projection optical system 130 may include an objective lens 131. The electron detection device 140M may include a plurality of detection elements 140_1, 140_2, and 140_3. The beam splitter 160 and the deflection scanning unit 132 may be located inside the main projection optical system 130.

[0039] The electron source 101, the aperture plate 171, the condenser lens 110, the source conversion unit 120, the beam splitter 160, the deflection scanning unit 132 and the main projection optical system 130 can be aligned with the main optical axis 100_1 of the device 100. The secondary imaging system 150 and the electron detection device 140M can be aligned with the auxiliary optical axis 150_1 of the device 100.

[0040] The electron source 101 may include a cathode (not shown) and an extractor and / or an anode (not shown), wherein during operation, the electron source 101 is configured to emit primary electrons from the cathode, and the primary electrons are extracted and / or accelerated by the extractor and / or the anode to form a primary electron beam 102, which forms a primary beam cross (virtual or real) 101s. The primary electron beam 102 can be visualized as being emitted from the primary beam cross 101s.

[0041] The source conversion unit 120 may include an image forming element array ( Figure 2 Not shown), field curvature compensator array ( Figure 2 Not shown), astigmatism compensator array ( Figure 2 not shown) and the beam limiting aperture array ( Figure 2). Examples of the source conversion unit 120 can be found in U.S. Patent No. 9,691,586, U.S. Publication No. 2017 / 0025243, and International Application No. PCT / EP2017 / 084429 (the entire contents of which are incorporated herein by reference). The image forming element array may include a plurality of micro-deflectors and / or micro-lenses to affect a plurality of primary beam waves 102_1, 102_2, 102_3 of the primary electron beam 102, and form a plurality of parallel images (virtual or real) of the primary beam cross 101s, one parallel image for each primary beam wave 102_1, 102_2, and 102_3. In some embodiments, such as when a micro-deflector is used to affect a plurality of primary beam waves 102_1, 102_2, 102_3 of the primary beam 102, a plurality of virtual images of the source 101 are formed. In other embodiments, multiple real images of the source 101 are formed, such as when microlenses are used to affect the multiple primary beam waves 102_1, 102_2, 102_3 of the primary beam 102. The field curvature compensator array may include multiple microlenses for compensating for field curvature aberrations of the primary beam waves 102_1, 102_2, and 102_3. The astigmatism compensator array may include multiple micro-stigmatizers for compensating for astigmatism aberrations of the primary beam waves 102_1, 102_2, and 102_3. The beam limiting aperture array may be configured to limit the diameter of the individual primary beam waves 102_1, 102_2, and 102_3. Figure 2 As an example, three primary beams 102_1, 102_2, and 102_3 are shown, and it should be understood that the source conversion unit 120 can be configured to form any number of primary beams. The source conversion unit 120 can be connected to the controller 109, which can generate a signal for controlling the source conversion unit 120. Figure 1 Various control signals for the operation of the EBI system 1.

[0042] The condenser lens 110 is configured to focus the primary electron beam 102. The condenser lens 110 may also be configured to adjust the current of the primary beam waves 102_1, 102_2, and 102_3 downstream of the source conversion unit 120 by changing the focal length of the condenser lens 110. Alternatively, the current may be changed by changing the radial size of the beam limiting aperture within the beam limiting aperture array corresponding to a single primary beam wave. The current may be changed by changing both the radial size of the beam limiting aperture and the focal length of the condenser lens 110. The condenser lens 110 may be a movable condenser lens, which may be configured such that the position of its first principal plane is movable. The movable condenser lens may be configured to be magnetic, which may cause the off-axis beam waves 102_2 and 102_3 to land on a beam limiting mechanism (e.g., Figure 3AThe rotation angle varies with the focal length of the movable focusing lens and the position of the first principal plane. In some embodiments, the movable focusing lens can be a movable anti-rotation focusing lens, which includes an anti-rotation lens having a movable first principal plane. The movable focusing lens is further described in U.S. Publication No. 2017 / 0025241 (the entire contents of which are incorporated herein by reference). Anti-rotation lenses and anti-rotation movable focusing lenses are further described in International Application No. PCT / EP2017 / 084429 (the entire contents of which are incorporated herein by reference).

[0043] The objective lens 131 (further explained below) can be configured to focus the beams 102_1, 102_2, and 102_3 onto the sample 8 for inspection, and in the current embodiment, three detection spots 102_1s, 102_2s, and 102_3s can be formed on the surface 7. The aperture plate 171 is configured to block peripheral electrons of the primary electron beam 102 in operation to reduce the Coulomb effect. The Coulomb effect may increase the size of each detection spot 102_1s, 102_2s, and 102_3s of the primary beams 102_1, 102_2, 102_3, and thus reduce the inspection resolution.

[0044] The beam splitter 160 may be, for example, a Wien filter, which includes generating an electrostatic dipole field E1 and a magnetic dipole field B1 (both of which are not Figure 2 1 and 102_3). In operation, the beam splitter 160 can be configured to exert an electrostatic force on the individual electrons of the primary beam waves 102_1, 102_2, and 102_3 through the electrostatic dipole field E1. The electrostatic force is equal in magnitude but opposite in direction to the magnetic force exerted on the individual electrons by the magnetic dipole field B1 of the beam splitter 160. The primary beam waves 102_1, 102_2, and 102_3 can therefore pass through the beam splitter 160 at least substantially straight with a deflection angle of at least substantially zero.

[0045] In operation, the deflection scanning unit 132 is configured to deflect the primary beam waves 102_1, 102_2 and 102_3 to scan the detection spots 102_1s, 102_2s and 102_3s on a single scanning area in the segment of the surface 7. In response to the incidence of the primary beam waves 102_1, 102_2 and 102_3 at the detection spots 102_1s, 102_2s and 102_3s, electrons are emitted from the sample 8 and three secondary electron beams 102_1se, 102_2se and 102_3se are generated. Each of the secondary electron beams 102_1se, 102_2se and 102_3se generally includes electrons with different energies, including secondary electrons (electron energy ≤ 50eV) and backscattered electrons (electron energy is between 50eV and the landing energy of the primary beam waves 102_1, 102_2 and 102_3). The beam splitter 160 is configured to deflect the secondary electron beams 102_1se, 102_2se, and 102_3se toward the secondary imaging system 150. The secondary imaging system 150 then focuses the secondary electron beams 102_1se, 102_2se, and 102_3se onto the detection elements 140_1, 140_2, and 140_3 of the electron detection device 140M. The detection elements 140_1, 140_2, and 140_3 are arranged to detect the corresponding secondary electron beams 102_1se, 102_2se, and 102_3se and generate corresponding signals, which are sent to a signal processing unit (not shown), for example, to construct an image of the corresponding scanning area of ​​the sample 8.

[0046] Reference now Figure 3A , Figure 3A is a schematic diagram of an exemplary multi-beam device 200A according to an embodiment of the present disclosure, which includes Figure 1 200A. An exemplary configuration of a source conversion unit 120 of an exemplary electron beam inspection system. In some embodiments, the device 200A may include an electron source 101, a gun hole plate 171, a condenser lens 110, a source conversion unit 120, an objective lens 131, and a sample 8 having a sample surface 7. The electron source 101, the gun hole plate 171, the condenser lens 110, the source conversion unit 120, and the objective lens 131 are aligned with the main optical axis 200_1 of the device. The electron source 101 generates a primary electron beam 102 along the main optical axis 200_1 and having a source cross (virtual or real) 101s. The gun hole plate 171 cuts off peripheral electrons of the primary electron beam 102 to reduce the Coulomb effect. The primary electron beam 102 can be trimmed into three beams 102_1, 102_2, and 102_3 by three beam forming holes (not shown) of a pre-beam forming mechanism (not shown).

[0047] The condenser lens 110 may focus the three beams 102_1 to 102_3 to become parallel beams along the main optical axis 200_1 and be vertically incident on the source conversion unit 120 .

[0048] In some embodiments, the source conversion unit 120 may include a beam limiting aperture array 121 having beam limiting apertures 121_1, 121_2, and 121_3 configured to limit beam waves 102_1, 102_2, and 102_3 of the primary electron beam 102. The source conversion unit 120 may also include an image forming element array 122-1 having image forming micro deflectors 122_1d, 122_2d, and 122_3d configured to deflect the beam waves 102_1, 102_2, and 102_3 toward the optical axis 200_1 to form detection spots 102_1S, 102_2S, and 102_3S. The source conversion unit 120 may further include an aberration compensator array 122_2 configured to compensate for the aberrations of the detection spots 102_1S, 102_2S, and 102_3S. In some embodiments, the aberration compensator array 122_2 may include a field curvature compensator array 122_2fc having microlenses 122_11, 122_2l, and 122_3l, and the microlenses 122_11, 122_2l, and 122_3l are configured to compensate for the field curvature aberrations of the detection spots 102_1S, 102_2S, and 102_3S, respectively. In some embodiments, the aberration compensator array 122_2 may include an astigmatism compensator array 122~2as having micro-stigmatizers 122_1s, 122_2s, and 122_3s~, and the micro-stigmatizers 122_1s, 122_2s, and 122_3s are configured to compensate for the astigmatism aberrations of the detection spots 102_1S, 102_2S, and 102_3S, respectively. In some embodiments, the image forming element array 122~1, the field curvature compensator array 122_2fc, and the astigmatism compensator array 122~2as may include multi-layer micro-deflectors, micro-lenses, and micro-stigmatizers, respectively. The multi-layer array is further described in U.S. Patent Application No. 62 / 567,134 (the entire contents of which are incorporated herein by reference).

[0049] In the source conversion unit 120, the beams 102_1, 102_2 and 102_3 of the primary electron beam 102 are deflected toward the main optical axis 200_1 by the micro deflectors 122_1d, 122_2d and 122_3d of the image forming element array 122-1, respectively. It can be understood that the beam 102_1 may be on the optical axis 200_1 before reaching the micro deflector 122_1d; therefore, the beam 102_1 may not be deflected by the micro deflector 122_1d.

[0050] The objective lens 131 focuses the beam onto the surface 7 of the sample 8, that is, projects three virtual images onto the surface 7. The three images formed by the three beams 102_1 to 102_3 on the surface 7 form three detection spots 102_1S, 102_2S and 102_3S thereon. The deflection angles of the beams 102_1 to 102_3 are adjusted to reduce the off-axis aberrations of the three detection spots 102_1S to 102_3S caused by the objective lens 131, and the three deflected beams therefore pass through or approach the front focus of the objective lens 131. The deflection angle used to form the detection spots corresponds to the radial offset (the distance from the optical axis 200_1) of the beam. For example, beams with the same radial offset have the same or substantially the same deflection angle. In addition, the deflection direction of the beam is related to its corresponding radial offset direction. Furthermore, the aberrations (eg, field curvature aberration and astigmatism aberration) of beams having the same or substantially the same radial offset are the same or substantially the same, and the direction of the astigmatism aberration is related to the direction of their radial offset.

[0051] The deflection direction of the beam can also be changed based on the presence of a magnetic field at the electron source 101 or the sample 8. In some embodiments, neither the electron source 101 nor the sample 8 can be immersed in a magnetic field (not shown). In such embodiments, the deflection direction is opposite to the radial offset direction, such as Figure 3B As shown. Figure 3B In the embodiment, the deflection directions 102_2D and 102_3D of the beams 102_2 and 102_3 are opposite to their corresponding radial offset directions 102_2R and 102_3R. ​​In other embodiments, at least one of the electron source 101 and the sample 8 may be immersed in a magnetic field. In such an embodiment, Figure 3C As shown, the deflection direction is rotated by a deflection rotation angle relative to the radial offset direction. Figure 3C , the deflection directions 102_2D and 102_3D of the beams 102_2 and 102_3 are rotated by a deflection rotation angle β relative to their corresponding radial offset directions 102_2R and 102_3R.

[0052] Reference now Figure 3D , Figure 3D An exemplary multipole structure with a dipole configuration according to an embodiment of the present disclosure is shown. The multipole structure includes two or more segmented electrodes. In some embodiments, the multipole structure can be Figure 3A The multipole structure may have a central axis and one or more symmetry planes P bisecting a pair of opposing segmented electrodes. The orientation direction A of the multipole structure is the direction of one of the symmetry planes and is perpendicular to the central axis. The radial offset direction R of the multipole structure is from Figure 3A The direction from the optical axis 200_1 to the central axis. Figure 3DIn the exemplary dipole configuration shown, the orientation angle α is formed by the orientation direction A and the radial offset direction R. Similarly, Figure 3E and 3F , respectively, show exemplary multipole structures with quadrupole and octupole configurations. A dipole structure can only be oriented in its orientation direction (e.g., Figure 3D Thus, if a dipole structure is used as a micro-deflector, the dipole structure can be positioned so that the orientation direction matches the deflection direction of the corresponding beam.

[0053] In some embodiments, the dipole field as an electric field is generated by the micro-deflector and is substantially perpendicular to the main optical axis 200_1. Figure 3A , the path of the beam is parallel to the main optical axis 200_1 when the beam enters the source conversion unit 122. In addition, when an electric field is present, the electric field can bend the beam in a direction diverging from (e.g., not parallel to) the path of the beam when the beam enters the source conversion unit 122. Figure 3A The optical axis 200_1 also spreads out. Figure 3A In the embodiment, 122_2d may be a multi-pole micro-deflector in which each pair of poles forms a pole of a dipole. When excitation is applied to the dipole, an electric field is formed between the two poles, wherein the electric field is substantially perpendicular to the main optical axis 200_1 and the path of the beam wave 102_2 when entering the source conversion unit 120, both of which are parallel to the central axis of the micro-deflector 122_2d. In addition, the electric field deflects the beam wave 102_2 in a direction diverging relative to the main optical axis 200_1 (the direction is the path of the beam wave 102_2 when the beam wave 102_2 enters the source conversion unit 120), and deviates from the central axis of the deflector 122_2d.

[0054] If a quadrupole structure or an octupole structure is used as a micro deflector, the quadrupole structure or the octupole structure can generate a dipole field in any direction perpendicular to its central axis by controlling the voltage applied to each electrode. Moreover, the quadrupole structure can generate only a dipole field in the direction in which it is oriented (e.g., Figure 3E The quadrupole field is aligned with the orientation direction A in the beam. Therefore, if the quadrupole structure is used as a micro-stigmator, the quadrupole structure can be positioned so that the orientation direction matches the astigmatism aberration direction of the corresponding beam. If the octopole structure is used as a micro-stigmator, there is no such limitation because it can generate a quadrupole field in any direction perpendicular to its central axis by controlling the voltage applied to each electrode.

[0055] For example, when one voltage is applied to all electrodes, the multipole structure is configured to function as a microlens. If the multipole structure has four segmented electrodes (i.e., a quadrupole structure) and two voltages having the same absolute value but opposite polarities are applied to two pairs of opposing electrodes, the multipole structure is configured to function as a micro-stigmator having a quadrupole field whose value can be changed but whose direction is fixed. For example, in Figure 3E In , when V1 is applied to electrodes e1 and e3, and when ~V1 is applied to electrodes e2 and e4, the multipole structure acts as such a micro-stigmator. The value of the quadrupole field can be changed by changing V1. If the multipole structure has eight segmented electrodes (i.e., an octupole structure) and two voltages of the same absolute value and opposite polarity are applied to two pairs of opposing electrodes, and another two voltages of the same absolute value and opposite polarity are applied to another two pairs of opposing electrodes, the multipole structure is configured to act as a micro-stigmator whose quadrupole field can be changed in both value and direction. For example, in Figure 3F In , when V1 is applied to electrodes e1 and e5, ~V1 is applied to electrodes e3 and e7, V2 is applied to electrodes e2 and e6, and ~V2 is applied to electrodes e4 and e8, the multipole structure acts as such a micro-stigmator. The value and direction of the quadrupole field can be changed by changing V1 and V2. If a multipole structure has four segmented electrodes (i.e., a quadrupole structure) and two voltages of the same absolute value and opposite polarity are applied to one pair of opposing electrodes, and another two voltages of the same absolute value and opposite polarity are applied to another pair of opposing electrodes, the multipole structure is configured to act as a micro-deflector. For example, in Figure 3E In the example, when V1 is applied to e2, ~V1 is applied to e4, V2 is applied to e1, and ~V2 is applied to e3, the multipole structure acts as a microdeflector. The value and direction of the dipole field can be changed by changing V1 and V2.

[0056] Reference now Figure 4A . Figure 4A The present invention is a diagram showing an embodiment of the present invention. Figure 3ASchematic diagram of an exemplary configuration of an array of image forming elements. In this embodiment, each microdeflector includes an octupole structure having eight segmented electrodes, and the eight segmented electrodes are excited separately and independently. For example, in this embodiment, the eight electrodes of microdeflector 122_2d are individually driven by eight outputs of the excitation driver 122_2d_D. In addition, nine microdeflectors need to be controlled separately. Therefore, for this three-by-three array structure, a total of 9 drivers and 72 connecting circuit lines are required. And, as more beam waves are used, the circuits connecting the microdeflectors become more and more complex, and the excitation voltages in the connecting lines become higher and higher. This increased level of complexity may cause problems as the number of beam waves increases. First, electrical interference between adjacent connecting lines may cause problems in maintaining signal integrity. In addition, if the voltage is high enough, the electric field between two adjacent lines may produce arcs. Second, when these drivers are located inside one or more vacuum chambers, the heat generated by these drivers may degrade system performance, and the exhaust of the heated drivers may deteriorate the vacuum state. Similar problems exist in field curvature compensator arrays with monopole structures, such as Figure 4B As shown. The monopole structure includes one or more ring electrodes. Therefore, the increased level of complexity brings the problem of increasing the number of beams used by the multi-beam system, thereby limiting the output. A solution (not shown) is proposed in U.S. Patent Application No. 62 / 567,134 (the entire contents of which are incorporated herein by reference). This solution is to Figure 4A One or more micro deflectors 122 to 1 in Figure 4B The corresponding micro lenses of 122-2fc in 122-1 are exchanged, such as exchanging the micro deflector 122_2d of 122-1 with the micro lens 122_2l of 122-2fc. The present disclosure proposes other solutions described below.

[0057] Reference now Figure 5A . Figure 5A 1 is a schematic diagram showing an exemplary configuration of an image forming element array 122-1 according to an embodiment of the present disclosure. In some embodiments, the image forming array 122-1 may include a plurality of micro deflectors 122_1d-122_25d positioned to have the same orientation angle α. Figure 5A In the example, the orientation angle α is equal to 22.5 degrees. Figure 5B As another example, the orientation angle is equal to zero degrees. Figure 3A The micro deflectors with the same radial offset, such as micro deflectors 122_2d, 122_3d, 122_6d and 122_16d, of the Z-axis 200_1) in the embodiment may have the same or substantially the same deflection angles of the corresponding beams. Figure 3B and 3CAs described, for corresponding beam waves, the deflection rotation angles β of the micro-deflectors 122_1d~122_25d can be equal or substantially equal. For example, in some embodiments in which neither the electron source 101 nor the sample 8 is immersed in a magnetic field, the deflection rotation angle β can be equal to zero degrees. In other embodiments in which at least one of the electron source 101 and the sample 8 is immersed in a magnetic field, the deflection rotation angle β can be 1 mrad (milliradians). Therefore, in the image forming element array 122~1, a group of multi-pole deflectors having the same or substantially the same radial offset and the same or substantially the same orientation angle α can be grouped to share a common driver.

[0058] Thus, in some embodiments, the micro-deflectors 122_1d-122_25d of the image forming element array 122-1 can be grouped into six different groups, each group including one or more micro-deflectors. Each micro-deflector in a given group can be driven by a corresponding group of drivers. For example, group 1 (in Figure 5A 122_2d, 122_3d, 122_6d, and 122_16d. Group 3 (G3) may include 122_7d, 122_8d, 122_17d, and 122_18d. Group 4 (G4) may include 122_4d, 122_5d, 122_11d, and 122_21d. Group 5 (G5) may include 122_9d, 122_10d, 122_12d, 122_13d, 122_19d, 122_20d, 122_22d, and 122_23d. Group 6 (G6) may include 122_14d, 122_15d, 122_24d, and 122_25d. The micro-deflector 122_1d in group 1 can have the smallest radial offset because it is located on the optical axis. The micro-deflectors 122_14d, 122_15d, 122_24d, and 122_25d in group 6 can have the largest radial offset because they are located at each corner of the array and are farthest from the optical axis. In addition, in such an embodiment, the micro-deflectors 122_14d, 122_15d, 122_24d, and 122_25d in group 6 can be driven by the highest deflection voltage to deflect the corresponding beam waves by a larger deflection angle because the micro-deflectors with larger radial offsets in the group deflect the beam waves more strongly toward the optical axis. Although Figure 5A and 5B A five by five array configuration is shown, but it should be understood that the array can be any size.

[0059] In some embodiments, the micro-deflectors 122_1d-122_25d can be grouped based on the proximity of the radial offset relative to the optical axis. For example, micro-deflectors with radial offset differences within a range of 10% can be grouped together and connected to a corresponding set of drivers. In some embodiments, the auxiliary micro-deflector array 122-1a (such as Figure 5C As shown) can be used to compensate for the effects of a 10% range. In some embodiments, the effects of a 10% range can be compensated for by appropriately designing the diameter of the microdeflector. For example, if a first microdeflector having a first diameter is radially offset further away from the optical axis than a second microdeflector having a second diameter, the first diameter can be reduced so that the same voltage can still be applied to the first and second microdeflectors while compensating for the difference in radial offset. That is, the same voltage applied to the two microdeflectors may result in a larger deflection angle caused by the first microdeflector having a smaller diameter than the deflection angle caused by the second microdeflector having a larger diameter. Although described using a microdeflector as an example, it should be understood that the same diameter variation technology can be used for microlenses and micro-stigmators.

[0060] In some embodiments, the micro deflectors 122_1d to 122_25d of the image forming element array 122-1 may include a plurality of segmented electrodes. Figure 5A As an example, eight segmented electrodes (octopoles) in each micro-deflector are shown, and it should be understood that the micro-deflector can be configured with any even number of segmented electrodes. The segmented electrodes in each micro-deflector can be labeled according to the angle with the orientation direction of the micro-deflector. For example, Figure 5A As shown, the first electrode that is at a first angle to the alignment direction can be considered as electrode e1, and the second electrode that is at a second angle to the alignment direction can be considered as electrode e2. Figure 5A Electrodes e1 and e2 of the multipole deflector in group 5 are shown only as examples, and it should be understood that any of the eight electrodes can be considered as electrode e1. In such an embodiment, electrode e1 in the multipole deflectors (122_9d, 122_10d, 122_12d, 122_13d, 122_19d, 122_20d, 122_22d, and 122_23d) in group 5 can be connected by the corresponding group driver 122~1_D5 and driven with a first voltage. Similarly, electrode e2 in group 5 can be connected by driver 122~1_D5 and driven with a second voltage. In such an embodiment, the remaining electrodes in group 5 (e3~e8, not shown) can also be driven by drivers 122~1_D5 with corresponding voltages. In addition, although Figure 5A The driver 122-1_D5 is shown to be located in a vacuum with the image forming element array 122-1, but it should be understood that the driver 122-1_D5 can be as shown in FIG. Figure 5BShown outside of vacuum. Figure 4A This embodiment reduces the number of drivers from 25 drivers (one for each micro-deflector) to only 6 drivers compared to the embodiment of FIG. 1 , and reduces the number of connecting circuits in the array configuration by driving a common set of voltages to the micro-deflectors in a group.

[0061] Reference now Figure 5B , Figure 5B 1 is a schematic diagram illustrating an exemplary configuration of an image forming element array 122 - 1 according to an embodiment of the present disclosure. Figure 5B FIG. 1 shows a configuration of micro deflectors 122_1d to 122_25d each having an orientation angle equal to zero degrees. Figure 5A As shown, the driver (e.g., 122-1_D5) can be positioned inside the vacuum. In other embodiments, such as Figure 5B As shown, the driver (e.g., 122-1_D5) can be positioned outside the vacuum to avoid exhaust, while the interface unit 122-1_I is positioned inside the vacuum and is configured to provide connection between the micro deflectors 122_1d~122_25d and the driver (e.g., 122-1_D5) outside the vacuum.

[0062] Reference now Figure 5C , Figure 5C 5A is a schematic diagram showing an exemplary source conversion unit having an array of image forming elements 122-1 and an array of auxiliary micro-deflectors 122-1a according to an embodiment of the present disclosure. As explained with respect to 5A, all micro-deflectors in a given group can be driven by a corresponding group driver. However, some inconsistencies may occur (e.g., based on manufacturing errors), which may result in slightly different deflection angles or deflection directions between micro-deflectors in the same group. In some embodiments, a control unit such as a micro-deflector may be used. Figure 5C The image forming element array 122-1 may have an auxiliary array such as the auxiliary micro deflector array 122-1a in the image forming element array 122-1a. Figure 5A The array configuration shown has six groups based on radial offset. The auxiliary micro-deflector array 122-1a may include a micro-deflector array having a configuration similar to that of the image forming element array 122-1. Each micro-deflector in the image forming element array 122-1 and a corresponding micro-deflector in the auxiliary micro-deflector array 122-1a are aligned with each other so that a pair of micro-deflectors from the two arrays can provide a deflection angle for a corresponding beam wave. The auxiliary micro-deflector array 122-1a differs from the image forming element array 122-1 in that the micro-deflectors in the auxiliary array may not be grouped. Figure 4AAs shown, the micro-deflectors in the auxiliary array can be driven individually or separately to provide fully independent controllability of each micro-deflector. For example, assuming that due to the previously mentioned inconsistency, the expected deflection angle of the micro-deflectors 122_14d, 122_15d, 122_24d and 122_25d in the group 6 of the image forming element array 122~1 is equal to 30mrad, when a set of voltages are applied, the actual deflection angles generated by the micro-deflectors 122_14d, 122_15d, 122_24d and 122_25d can be 30.1, 30, 29.8, 29.9mrad, respectively. In this case, the corresponding micro-deflectors in the auxiliary micro-deflector array 122~1a can be individually controlled to provide further deflections of ~0.1, 0, 0.2, 0.1mrad, respectively. As a result, the beam waves leaving the image forming element array 122-1 and the auxiliary micro-deflector array 122-1a are all deflected by 30mrad. Although the auxiliary micro-deflector array 122-1a requires more drivers, since it does not utilize the grouping technology, the problem is not as serious as in the image forming element array 122-1, because the voltage used for the micro-deflectors in the auxiliary array is very small, as shown in the above example. In addition, due to the aforementioned inconsistency, the actual deflection rotation angle β of the micro-deflectors 122_14d, 122_15d, 122_24d and 122_25d may be slightly different from the expected one, respectively. In this case, the corresponding micro-deflectors in the auxiliary micro-deflector array 122-1a can be individually controlled to provide further deflection to meet the required deflection rotation angle β.

[0063] Reference now Fig. 6A and 6B , Fig. 6A and 6B 2 is a schematic diagram showing an exemplary configuration of a field curvature compensator array 122 ˜ 2fc according to an embodiment of the present disclosure. The field curvature compensator array 122 ˜ 2fc may include a plurality of micro lenses 122_1_1 ˜ 122_251 . Fig. 6A and 6B Unipolar microlenses 122_11 to 122_251 are shown as examples. Although microlenses 122_11 to 122_251 may have a unipolar structure, it should be understood that some or all of microlenses 122_11 to 222_251 may have a multipolar structure, wherein the segmented electrodes within each multipolar structure are configured to be driven by a common voltage. Figure 5A and 5B The described grouping techniques and other embodiments may also be applied to the field curvature compensator arrays 122-2fc. In addition, in some embodiments, such as Fig. 6A As shown, the driver (e.g., 122-2fc_D5) can be positioned inside the vacuum. In other embodiments, such as Figure 6B As shown, the driver (e.g., 122-2fc_D5) can be positioned outside the vacuum to avoid exhaust, while the interface unit 122-2fc_I is positioned inside the vacuum and is configured to provide a connection between the micro-deflectors 122_11-122_251 and the driver (e.g., 122-2fc_D5) outside the vacuum. One difference is that a micro-lens group with a smaller radial offset may use a higher focusing voltage. Although Fig. 6A and 6B A five by five array configuration is shown, but it should be understood that the array may be any size.

[0064] Reference now Figure 6C , Figure 6C is a schematic diagram showing an exemplary source conversion unit in a multi-beam device having a field curvature compensator array 122~2fc and an auxiliary microlens array 122~2fca according to an embodiment of the present disclosure. The auxiliary microlens array 122~2fca can compensate for the inconsistency of the field curvature aberration of the field curvature compensator array 122~2fc. Each microlens in the field curvature compensator array 122~2fc and a corresponding auxiliary microlens in the auxiliary microlens array 122~2fca are aligned with each other so that a pair of microlenses from the two arrays can affect the field curvature aberration of the corresponding beam wave. The auxiliary microlens array 122~2fca differs from the field curvature compensator array 122~2fc in that the microlenses in the auxiliary array may not be grouped. The microlenses in the auxiliary array may be as follows: Figure 4B The microlenses are driven individually and separately to provide complete independent controllability of each microlens. Figure 6C The auxiliary microlens array 122-2fca is shown as being located below the field curvature compensator array 122-2fc. It is understood that the auxiliary microlens array 122-2fca may be located above the field curvature compensator array 122-2fc.

[0065] Reference now Fig. 7A and 7B , Fig. 7A and 7B 2 is a schematic diagram showing an exemplary configuration of an astigmatism compensator array 122-2as according to an embodiment of the present disclosure. Fig. 7A and 7B The micro-stigmators 122_1s to 122_25s having an octapole structure are shown, and it should be understood that some or all of the micro-stigmators 122_1s to 122_25s may have a multipole structure having any even number of segmented electrodes. Figure 5A and 5B The described grouping techniques and other embodiments may also be applied to the astigmatism compensator array 122-2as. In addition, in some embodiments, such as Fig. 7AAs shown, the driver (e.g., 122-2as_D5) can be positioned inside the vacuum. In other embodiments, such as Figure 7B As shown, the driver (e.g., 122-2as_D5) can be positioned outside the vacuum to avoid exhaust, while the interface unit 122-2as_I is positioned inside the vacuum and is configured to provide a connection between the micro deflectors 122_1s-122_25s and the driver (e.g., 122-2as_D5) outside the vacuum. Fig. 7A and 7B A five by five array configuration is shown, but it should be understood that the array can be any size.

[0066] In some embodiments, if the voltage applied to the micro-stigmators of the astigmatism compensator array 122-2as is not high, the astigmatism compensator array 122-2as can be used to perform the function of an auxiliary micro-deflector array or an auxiliary micro-lens array or both. In some embodiments, the astigmatism compensator array 122-2as can perform the function of an auxiliary array (e.g., Figure 5C The auxiliary micro-deflector array 122-1a or Figure 6C In the embodiment, the auxiliary microlens array 122-2fca in the astigmatism compensator array 122-2as performs the function of the auxiliary microlens array 122-2fca in the astigmatism compensator array 122-2as, and in the configuration without the dedicated auxiliary microdeflector array 122-1a or the auxiliary microlens array 122-2fca, performs the astigmatism compensation function. In such an embodiment, the micro-stigmatizers of the astigmatism compensator array 122-2as may not be grouped, but may be driven individually and separately to provide additional dipole fields or lens fields or both.

[0067] Figure 7C 1 is a schematic diagram showing a portion of an exemplary source conversion unit in a multi-beam device having an astigmatism compensator array 122-2as and an auxiliary micro-stigmatism stigmatism array 122-2asa according to an embodiment of the present disclosure. The auxiliary micro-stigmatism stigmatism array 122-2asa can compensate for the inconsistency of the astigmatism compensator array 122-2 regarding astigmatism aberration. The auxiliary micro-stigmatism stigmatism array 122-2asa may include a micro-stigmatism stigmatism array similar in configuration to the astigmatism compensator array 122-2as. Each micro-stigmatism stigmatism in the astigmatism compensator array 122-2as and a corresponding auxiliary micro-stigmatism stigmatism in the auxiliary micro-stigmatism stigmatism array 122-2asa are aligned with each other, so that a pair of micro-stigmatism stigmatism from the two arrays can affect the astigmatism aberration of the corresponding beam wave. The auxiliary micro-stigmatism stigmatism array 122-2asa is different from the astigmatism compensator array 122-2as in that the micro-stigmatism stigmatism in the auxiliary array may not be grouped. The micro-stigmators in the auxiliary array can be driven individually or separately to provide full independent controllability of each auxiliary micro-stigmator. Figure 7CThe auxiliary micro-stigmator array 122-2asa is shown positioned below the astigmatism compensator array 122-2as, but it should be understood that the auxiliary micro-stigmator array 122-2asa may be positioned above the astigmatism compensator array 122-2as.

[0068] Reference now Fig. 8A and 8B In order to reduce the complexity of the connection lines or circuits in an array of the above-mentioned microstructures, in some embodiments, Figure 5A One or more micro-deflectors of 122 to 1 can be used Fig. 6A Similarly, in some embodiments, as Fig. 7A One or more micro-stigmators of 122 to 2 can be used Fig. 6A In some embodiments, Figure 5A One or more micro-deflectors of 122 to 1 can be used Fig. 7A The corresponding micro-stigmator of 122~2 is replaced. For example, Fig. 8A An exemplary configuration of a microstructure array is shown, where four microlenses are replaced with micro-stigmators in group G3s, so the corresponding array becomes 122~2fc~2as. Similarly, Figure 8B An exemplary configuration of a microstructure array is shown, in which the four micro-stigmators are replaced by microlenses in group G31, so the corresponding array becomes 122~2as~2fc.

[0069] Reference now Fig. 9 , Fig. 9 is a flow chart illustrating an exemplary method 900 of controlling a plurality of drivers to form a plurality of detection spots according to an embodiment of the present disclosure. The method 900 may be performed by an electron beam tool (e.g., Figure 2 In particular, a controller of the electron beam tool (e.g., Figure 2 The controller 109) can execute method 900.

[0070] In step 910, a first driver in a first microstructure array is directed to control a first set of one or more voltages to a first group of one or more microstructures to affect a first group of corresponding one or more beams. In some embodiments, the first driver is connected to a first group of microstructures in the first microstructure array. In step 920, a second driver in the first microstructure array is directed to control a second set of one or more voltages to a second group of one or more microstructures to affect a second group of corresponding one or more beams. In some embodiments, the second driver is connected to a second group of microstructures in the first microstructure array.

[0071] In some embodiments, such as embodiments in which the source conversion unit includes a second microstructure array, steps 930 and 940 may be further performed. In step 930, a third driver in the second microstructure array is instructed to control a third group of one or more voltages of a third group of one or more microstructures to affect one or more beams corresponding to the first group. In step 940, a fourth driver in the second microstructure array is instructed to control a fourth group of one or more voltages of a fourth group of one or more microstructures to affect one or more beams corresponding to the second group. The microstructures described herein may be monopole structures or any type of multipole structures, such as dipole (2-pole) structures, quadrupole (4-pole) structures, octopole (8-pole) structures, and the like.

[0072] In some embodiments, the actuator may be positioned outside the vacuum to avoid exhaust. In such embodiments, the actuator may control a set of microstructures via an interface unit configured to provide a connection between the actuator and the multipolar structure.

[0073] Reference now Fig.10 , Fig.10 is a flow chart illustrating an exemplary method 1000 of fabricating an exemplary configuration of a microstructure array according to an embodiment of the present disclosure. In some embodiments, the microstructure array can be fabricated using semiconductor fabrication processes.

[0074] In step 1010, an array having a plurality of microstructures is formed as a base layer. The microstructures may be monopolar structures or any type of multipolar structures, such as dipole structures, quadrupole structures, octopole structures, etc. In step 1020, a connection layer may be formed to create connections for a first group of microstructures in the plurality of microstructures. In some embodiments, the microstructures in the first group are positioned close to or substantially at the same first radial offset from the central axis of the array. In step 1030, another connection layer may be formed to create connections for a second group of microstructures in the plurality of microstructures. In some embodiments, the microstructures in the second group are positioned close to or substantially at the same second radial offset from the central axis of the array. The connection layers in steps 1020 and 1030 may be connected directly to two different actuators, or to interfaces connected to two different actuators.

[0075] The embodiments may be further described using the following terms:

[0076] 1. A microstructure array, the array comprising:

[0077] A first set of monopolar structures has a first radial offset relative to the central axis of the array, wherein the first radial offset is equal or substantially equal, and the first set of monopolar structures includes corresponding electrodes electrically connected and driven by a first driver.

[0078] 2. A microstructure array according to clause 1, wherein the first driver is configured to enable the first group of monopole structures to function as microlenses to compensate for field curvature aberrations of corresponding beam spots in a charged particle multi-beam device.

[0079] 3. A microstructure array, the array comprising:

[0080] A first group of multipole structures has a first radial offset and a first orientation angle relative to the central axis of the array, wherein the first radial offset is equal or substantially equal, the first orientation angles of the first group of multipole structures are equal or substantially equal, and the first group of multipole structures includes corresponding electrodes electrically connected and driven by a first driver.

[0081] 4. A microstructure array according to clause 3, wherein the first driver is configured to enable the first group of multipole structures to be used as microdeflectors to deflect a first group of beam waves in a charged particle multi-beam device.

[0082] 5. The microstructure array according to clause 3, wherein the first driver is configured to enable the first group of multipole structures to be used as micro-stigmators to compensate for the astigmatic aberrations of the first group of beam spots in a charged particle multi-beam device.

[0083] 6. The microstructure array according to any one of clauses 4 and 5 further includes a second group of multipole structures, the second group of multipole structures having a second radial offset and a second orientation angle relative to the central axis, wherein the second radial offset is equal or substantially equal, and the second orientation angles of the second group of multipole structures are equal or substantially equal, and the second group of multipole structures includes corresponding electrodes electrically connected and driven by a second driver.

[0084] 7. The microstructure array according to clause 6, wherein the second driver is configured to enable the second group of multipole structures to be used as microdeflectors to deflect a second group of beam waves in the charged particle multi-beam device.

[0085] 8. The microstructure array according to clause 6, wherein the second driver is configured to enable the second group of multipole structures to function as micro-stigmators to compensate for astigmatic aberrations of a second group of beam spots in the charged particle multi-beam device.

[0086] 9. A microstructure array according to any one of clauses 4 and 5, further comprising a first group of monopolar structures, the first group of monopolar structures having a second radial offset relative to the central axis, wherein the second radial offset is equal or substantially equal, and the first group of monopolar structures comprises corresponding electrodes electrically connected and driven by a second driver.

[0087] 10. The microstructure array according to clause 9, wherein the second driver is configured to enable the first group of monopole structures to function as microlenses to compensate for field curvature aberrations of a second group of beam spots in the charged particle multi-beam device.

[0088] 11. A source conversion unit in a charged particle device, comprising:

[0089] A first microstructure array comprises a first group of multipole structures, wherein the first group of multipole structures has a first radial offset and a first orientation angle relative to the optical axis of the device, wherein the first radial offset is equal or substantially equal, the first orientation angles of the first group of multipole structures are equal or substantially equal, and the first group of multipole structures comprises corresponding electrodes electrically connected and driven by a first driver associated with the first microstructure array.

[0090] 12. A source conversion unit according to clause 11, wherein the first driver is configured to enable the first set of multipole structures to act as micro-deflectors to deflect a first set of beam waves of a charged particle beam to form a first set of detection spots in the device.

[0091] 13. The source conversion unit according to clause 12 further includes a second microstructure array, the second microstructure array including a first group of monopole structures respectively aligned with the first group of multipole structures, wherein the first group of monopole structures include corresponding electrodes electrically connected and driven by a second driver associated with the second microstructure array.

[0092] 14. A source conversion unit according to clause 13, wherein the second driver is configured to enable the first group of monopole structures to act as microlenses to influence the first group of beam waves to compensate for field curvature aberrations of the first group of detection spots.

[0093] 15. The source conversion unit according to clause 14 further includes a third microstructure array, wherein the third microstructure array includes a second group of multipole structures, wherein the second group of multipole structures are respectively aligned with the first group of multipole structures and have a second orientation angle, wherein the second orientation angles of the second group of multipole structures are the same or substantially the same, and the second group of multipole structures include corresponding electrodes electrically connected and driven by a third driver associated with the third microstructure array.

[0094] 16. A source conversion unit according to clause 15, wherein the third driver is configured to enable the second set of multipole structures to act as a micro-stigmator to influence the first set of beam waves to compensate for astigmatic aberrations of the first set of detection spots.

[0095] 17. The source conversion unit according to clause 14, further comprising a third microstructure array, the third microstructure array comprising a second set of multipole structures respectively aligned with the first set of multipole structures.

[0096] 18. A source conversion unit according to clause 17, wherein the second set of multipole structures are individually controlled to act as at least one of micro-deflectors, micro-stigmators and micro-lenses to further influence the first set of beam waves to affect the first set of detection spots.

[0097] 19. The source conversion unit according to clause 16, further comprising a first microstructure auxiliary array, the first microstructure auxiliary array comprising a third group of multipole structures respectively aligned with the first group of multipole structures.

[0098] 20. The source conversion unit of clause 19, wherein the third set of multipole structures are individually controlled to function as at least one of micro-deflectors, micro-stigmators, and micro-lenses to further influence the first set of beam waves to influence the first set of detection spots.

[0099] 21. The source conversion unit according to any one of clause 20, further comprising a second microstructure auxiliary array, the second microstructure auxiliary array comprising a second group of monopole structures respectively aligned with the first group of multipole structures.

[0100] 22. A source conversion unit according to clause 21, wherein the second set of monopole structures are individually controlled to act as microlenses to further influence the first set of beam waves to influence the first set of detection spots.

[0101] 23. A source conversion unit in a charged particle device, comprising:

[0102] a first microstructure array comprising: a first set of multipole structures having a first radial offset relative to an optical axis of the device, and a second set of multipole structures having a second radial offset relative to the optical axis; and

[0103] The second microstructure array includes: a first group of monopole structures respectively aligned with the first group of multipole structures, and a third group of multipole structures respectively aligned with the second group of multipole structures.

[0104] 24. A unit according to clause 23, wherein the first radial offsets are equal or substantially equal, the first set of multipolar structures have the same or substantially the same orientation angles, and their corresponding electrodes are electrically connected and driven by a first driver associated with the first microstructure array.

[0105] 25. A unit according to claim 24, wherein the second radial offsets are equal or substantially equal, the second set of multipolar structures have the same or substantially the same orientation angles, and their corresponding electrodes are electrically connected and driven by a second driver associated with the first microstructure array.

[0106] 26. A cell according to clause 25, wherein corresponding electrodes of the first set of monopolar structures are electrically connected and driven by a third driver associated with the second array of microstructures.

[0107] 27. A cell according to clause 26, wherein the third set of multipolar structures have the same or substantially the same orientation angles and their corresponding electrodes are electrically connected and driven by a fourth driver associated with the second microstructure array.

[0108] 28. A unit according to clause 27, wherein the first driver is configured to enable the first set of multipole structures to act as micro-deflectors to deflect a first set of beam waves of a charged particle beam to form a first set of detection spots in the device.

[0109] 29. A unit according to clause 28, wherein the third driver is configured to enable the first set of monopole structures to act as a microlens to influence the first set of beam waves to compensate for field curvature aberrations of the first set of detection spots.

[0110] 30. A unit according to clause 29, wherein the fourth driver is configured to enable the third set of multipole structures to act as micro-deflectors to deflect a second set of beam waves of the charged particle beam to form a second set of detection spots in the device.

[0111] 31. A unit according to clause 30, wherein the second driver is configured to enable the second set of multipole structures to act as a micro-stigmator to influence the second set of beam waves to compensate for astigmatic aberrations of the second set of detection spots.

[0112] 32. A unit according to clause 29, wherein the second driver is configured to enable the second multipole structure to act as a micro-deflector to deflect a second set of beam waves of the charged particle beam to form a second set of detection spots in the device.

[0113] 33. A unit according to clause 32, wherein the fourth driver is configured to enable the third multipole structure to act as a micro-stigmator to influence the second set of beam waves to compensate for astigmatic aberrations of the second set of detection spots.

[0114] 34. A non-transitory computer readable medium comprising a set of instructions executable by one or more processors of a controller to cause the controller to perform a method of forming an image of a sample, the method comprising:

[0115] instructing a first driver coupled to a first group of microstructures in a first array of microstructures to control a first group of one or more voltages to affect a first group of beams; and

[0116] A second driver coupled to a second set of microstructures in the first array is directed to control a second set of one or more voltages to affect a second set of beam waves.

[0117] 35. The computer-readable medium of clause 34, wherein the set of instructions is executable by the one or more processors of the controller to cause the controller to further perform:

[0118] instructing a third driver connected to a first group of microstructures in a second array of microstructures to control a third group of one or more voltages to affect the first group of beams; and

[0119] A fourth driver coupled to a second set of microstructures in the second array is directed to control a fourth set of one or more voltages to affect the second set of beams.

[0120] 36. The computer-readable medium of clause 34, wherein the set of instructions is executable by the one or more processors of the controller to cause the controller to further perform:

[0121] A plurality of third actuators coupled to a plurality of microstructures in a second array of microstructures are instructed to affect at least one of the first set of beams and the second set of beams.

[0122] 37. A method of manufacturing a microstructure array comprising a plurality of microstructures, the method comprising:

[0123] forming the plurality of microstructures around a central axis of the array;

[0124] forming a first set of connections between microstructures in a first set of microstructures in the plurality of microstructures, wherein the microstructures in the first set of microstructures are positioned at a first radial offset relative to the central axis; and

[0125] A second set of connections is formed between microstructures in a second set of microstructures in the plurality of microstructures, wherein the microstructures in the second set of microstructures are positioned at a second radial offset relative to the central axis.

[0126] 38. The method of clause 37, further comprising connecting the first set of connections to a first driver.

[0127] 39. The method of clause 37 or 38, further comprising connecting the second set of connections to a second driver.

[0128] 40. The method of clause 37, further comprising connecting the first set of connections to a first interface associated with a first driver.

[0129] 41. The method of clause 37 or 38, further comprising connecting the second set of connections to a second interface associated with a second drive.

[0130] 42. A method comprising:

[0131] controlling a first set of one or more microstructures in a first array of microstructures using a first driver to affect a first set of corresponding one or more beams; and

[0132] A second group of microstructures in the first array of microstructures is controlled using a second driver to affect a second group of corresponding one or more beams.

[0133] 43. The method according to clause 42, further comprising:

[0134] controlling a first group of one or more microstructures in a second array of microstructures using a third actuator to affect a first group of corresponding one or more beams; and

[0135] A second group of microstructures in the second array of microstructures is controlled using a fourth actuator to affect a second group of corresponding one or more beams.

[0136] 44. The method according to clause 42, further comprising:

[0137] Microstructures in a second array of microstructures are controlled to affect at least one of the first set of beams and the second set of beams.

[0138] 45. A charged particle beam device comprising:

[0139] Source conversion unit, comprising:

[0140] The first microstructure array comprises a plurality of microstructures, wherein the first microstructure array comprises:

[0141] a first group of microstructures of the plurality of microstructures, wherein the microstructures of the first group of microstructures have a first radial offset relative to an optical axis of the device and are driven by a first driver to affect a first group of beam waves of a charged particle beam; and

[0142] A second group of microstructures in the plurality of microstructures, wherein the microstructures in the second group of microstructures have a second radial offset relative to the optical axis and are driven by a second driver to affect a second group of beam waves of the charged particle beam.

[0143] 46. ​​The electron beam apparatus of clause 45, further comprising a movable focusing lens configured to focus the charged particle beam.

[0144] 47. The electron beam apparatus of clause 45, further comprising an anti-rotation focusing lens for focusing the charged particle beam.

[0145] 48. The electron beam apparatus of clause 45, further comprising a movable anti-rotation focusing lens for focusing the charged particle beam.

[0146] 49. A polar structure array comprising a plurality of polar structures, the polar structure array comprising:

[0147] a first set of pole structures in the plurality of pole structures, wherein the pole structures in the first set of pole structures are configured to be driven by a first driver and are positioned proximate a first radial offset relative to the optical axis; and

[0148] A second set of pole structures in the plurality of pole structures, wherein the pole structures in the second set of pole structures are configured to be driven by a second driver and are positioned proximate a second radial offset relative to the optical axis.

[0149] 50. An array of pole structures according to clause 49, wherein the plurality of pole structures have corresponding axes of symmetry, and the plurality of pole structures are rotated such that the corresponding axes of symmetry are substantially parallel to corresponding radial directions relative to the optical axis.

[0150] 51. A source conversion unit, comprising:

[0151] A first pole structure array, comprising a plurality of pole structures, wherein the first pole structure array comprises:

[0152] a first set of pole structures in the plurality of pole structures, wherein the pole structures in the first set of pole structures are configured to be driven by a first driver and are positioned proximate a first radial offset relative to the optical axis; and

[0153] A second set of pole structures in the plurality of pole structures, wherein the pole structures in the second set of pole structures are configured to be driven by a second driver and are positioned proximate a second radial offset relative to the optical axis.

[0154] 52. An array of microstructures according to clause 3, wherein a first micropole structure in the first set of multipole structures is configured to form a virtual image of an electron source.

[0155] 53. An array of microstructures according to clause 3, wherein each micropolar structure in the first set of multipolar structures is configured to form a virtual image of an electron source.

[0156] 54. An array of microstructures according to clause 3, wherein each micropolar structure in the first set of multipolar structures is configured to form a different virtual image of the same single electron source.

[0157] 55. The microstructure array of clause 3, wherein a first micropole structure in the first set of multipole structures is configured to generate an electric field substantially perpendicular to a central axis of the first micropole structure.

[0158] 56. A microstructure array according to claim 3, wherein the central axis of each micropole structure in the first group of multipole structures is substantially parallel to the central axis of each other micropole structure in the first group of multipole structures, and wherein each micropole structure in the first group of multipole structures is configured to generate an electric field substantially perpendicular to the central axis.

[0159] It should be understood that the controller of the multi-beam device can use software to control the above functions. For example, the controller can send instructions to the aforementioned lenses to generate appropriate fields (e.g., magnetic fields or electrostatic fields) respectively. The controller can also send instructions to the driver to adjust the voltage to control the above array. The software can be stored on a non-transient computer-readable medium. Common forms of non-transient media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, tapes or any other magnetic data storage media, CD-ROMs, any other optical data storage media, any physical media with hole patterns, RAM, PROM and EPROM, FLASH-EPROM or any other flash memory, NVRAM, caches, registers, any other storage chips or cassettes, and network versions of the above.

[0160] Although the disclosed embodiments have been explained with respect to the preferred embodiments thereof, it should be understood that other modifications and variations may be made without departing from the spirit and scope of the subject matter as hereinafter claimed.

Claims

1. A microstructure array, the array comprising: a first set of multipole structures, each multipole structure of the first set of multipole structures having a first radial offset and a first orientation angle relative to a first central axis of the array, wherein the first radial offsets of the first set of multipole structures are equal, the first orientation angles of the first set of multipole structures are equal, and the first set of multipole structures comprises corresponding electrodes electrically connected and driven by a shared first driver, wherein each multipolar structure comprises a second central axis, a plurality of segmented electrodes surrounding the second central axis, and one or more symmetry planes bisecting the opposing segmented electrodes, The first radial offset of each multipole structure indicates a distance from the first central axis to the second central axis in a radial offset direction from the first central axis to the second central axis, and The first orientation angle of each multipole structure indicates an angle between the radial offset direction and a direction in which a symmetry plane closest to the radial offset direction among the one or more symmetry planes is located. 2 . The microstructure array according to claim 1 , wherein the first driver is configured to enable the first group of multipole structures to be used as microdeflectors to deflect a first group of beam waves in a charged particle multi-beam device.

3. The microstructure array according to claim 1, wherein the first driver is configured to enable the first group of multipole structures to be used as a micro-stigmator to compensate for the astigmatic aberration of the first group of beam spots in a charged particle multi-beam device.

4. The microstructure array of claim 2, further comprising a second set of multipole structures having a second radial offset and a second orientation angle relative to the first central axis, wherein the second radial offsets are equal and the second orientation angles of the second set of multipole structures are equal, and the second set of multipole structures comprises corresponding electrodes electrically connected and driven by a second driver, wherein each multipole structure in the second group of multipole structures comprises a third central axis, a plurality of segmented electrodes surrounding the third central axis, and one or more second symmetry planes bisecting the opposing segmented electrodes, the second radial offset of each multipole structure in the second set of multipole structures indicates a distance from the first central axis to the third central axis in another radially offset direction from the first central axis to the third central axis, and The second orientation angle of each multipole structure in the second group of multipole structures indicates an angle between the other radial offset direction and a direction in which a second symmetry plane closest to the other radial offset direction among the one or more second symmetry planes is located. 5 . The microstructure array according to claim 4 , wherein the second driver is configured to enable the second group of multipole structures to be used as micro-deflectors to deflect a second group of beam waves in the charged particle multi-beam device. 6 . The microstructure array according to claim 4 , wherein the second driver is configured to enable the second group of multipole structures to function as micro-stigmators to compensate for astigmatism aberrations of the second group of beam spots in the charged particle multi-beam device.

7. The microstructure array of claim 2, further comprising a first set of monopolar structures having a second radial offset relative to the first central axis, wherein the second radial offsets are equal and the first set of monopolar structures comprises corresponding electrodes electrically connected and driven by a second driver, and Wherein each monopole structure of the first set of monopole structures includes a fourth central axis, and the second radial offset indicates a distance from the first central axis to the fourth central axis.

8. The microstructure array according to claim 7, wherein the second driver is configured to enable the first group of monopole structures to function as microlenses to compensate for field curvature aberrations of a second group of beam spots in the charged particle multi-beam device.

9. The microstructure array of claim 1, wherein the first multipole structure in the first group is configured to form a virtual image of an electron source.

10. The microstructure array of claim 1, wherein each multipole structure in the first group is configured to form a virtual image of an electron source.

11. The microstructure array of claim 1, wherein each multipole structure in the first group is configured to form a different virtual image of the same single electron source.

12. The microstructure array of claim 1, wherein a first multipole structure in the first group is configured to generate an electric field substantially perpendicular to the second central axis of the first multipole structure.

13. A source conversion unit in a charged particle device, comprising: a first microstructure array comprising a first set of multipole structures, each multipole structure of the first set of multipole structures having a first radial offset and a first orientation angle relative to an optical axis of the device, wherein the first radial offsets of the first set of multipole structures are equal, the first orientation angles of the first set of multipole structures are equal, and the first set of multipole structures comprises corresponding electrodes electrically connected and driven by a first driver associated with the first microstructure array, wherein each multipolar structure comprises a central axis, a plurality of segmented electrodes surrounding the central axis, and one or more symmetry planes bisecting the opposing segmented electrodes, The first radial offset of each multipole structure indicates a distance from the optical axis to the central axis in a radial offset direction from the optical axis to the central axis, and The first orientation angle of each multipole structure indicates an angle between the radial offset direction and a direction in which a symmetry plane closest to the radial offset direction among the one or more symmetry planes is located.

14. The source conversion unit according to claim 13, wherein the first driver is configured to enable the first set of multipole structures to act as micro-deflectors to deflect a first set of beam waves of the charged particle beam to form a first set of detection spots in the device.

15. A method for manufacturing a microstructure array comprising a plurality of microstructures, the method comprising: forming the plurality of microstructures around a first central axis of the array; forming a first set of connections between microstructures in a first set of microstructures in the plurality of microstructures, wherein the microstructures in the first set of microstructures are positioned at a first radial offset relative to the first central axis, wherein each microstructure in the first set of microstructures includes a second central axis, and the first radial offset of each microstructure indicates a distance from the first central axis to the second central axis in a radially offset direction from the first central axis to the second central axis; as well as forming a second set of connections between microstructures in a second group of microstructures in the plurality of microstructures, wherein the microstructures in the second group of microstructures are positioned at a second radial offset relative to the first central axis, wherein each microstructure in the second group of microstructures includes a third central axis, and the second radial offset of each microstructure indicates a distance from the first central axis to the third central axis in a radial offset direction from the first central axis to the third central axis.

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