Electron beam device and image acquisition method

Abstract

The electron beam apparatus according to the embodiment includes: a support portion that supports a sample; electrodes disposed below the sample supported by the support portion and capable of applying a voltage to the sample, the electrodes including a plurality of columnar electrodes capable of independently setting the voltage; and a control portion capable of generating correction data for correcting the electric field distribution generated on the sample based on structural information representing the structure of the sample, and controlling the plurality of columnar electrodes based on the correction data.

Description

[0001] Related applications

[0002] This application is based on and claims the benefit of priority arising from the prior Japanese Patent Application No. 2020-152972, filed on September 11, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments of the present invention relate to an electron beam device and an image acquisition method. Background Technology

[0004] Imprint lithography is a known process in semiconductor manufacturing. In imprint lithography, a template is pressed onto a resist film formed on the layer to be etched, and the resist film is processed into an etching mask. The template used for imprint lithography has a pattern that is the same size as the pattern formed on the semiconductor device. As semiconductor devices become smaller, the patterns on the templates also become smaller. In order to use such a template in the manufacture of semiconductor devices, it is first necessary to inspect and measure the pattern on the template, but the miniaturization of the template makes inspection and measurement difficult.

[0005] Main contents of the invention

[0006] One embodiment provides an electron beam apparatus and an image acquisition method capable of improving the accuracy of inspection and measurement of minute patterns.

[0007] According to one embodiment, an electron beam apparatus is provided. The electron beam apparatus includes: a support portion supporting a sample; electrodes disposed below the sample supported by the support portion and capable of applying a voltage to the sample, the electrodes comprising a plurality of columnar electrodes capable of independently setting the voltage; and a control unit capable of generating correction data for correcting the electric field distribution generated by the sample based on structural information representing the structure of the sample, and controlling the plurality of columnar electrodes based on the correction data.

[0008] Based on the above configuration, an electron beam device and image acquisition method can be provided that can improve the accuracy of inspection and measurement of minute patterns. Brief description of the attached figures

[0009] Figure 1 This is an example of a block diagram showing the general configuration of the electron beam device according to this embodiment.

[0010] Figure 2 (A) is a schematic top view showing the deceleration electrode. Figure 2 (B) is a partial perspective view schematically showing the upper end of the cylindrical electrode of the deceleration electrode.

[0011] Figure 3 This is a flowchart illustrating the image acquisition method involved in the implementation method.

[0012] Figure 4 (A) is a schematic diagram showing the structure of a template created based on the mesa structural information. Figure 4 (B) is a diagram showing the electric field correction plot calculated using the platform structure information.

[0013] Figure 5 (A) is a schematic top view showing the deceleration electrode of the electron beam device according to a modified embodiment. Figure 5 (B) is along Figure 5 A partial sectional view of the LL line in (A).

[0014] Figure 6 This is a flowchart illustrating an image acquisition method implemented using an electron beam apparatus according to a variation of the embodiment. Detailed Implementation

[0015] Hereinafter, non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. Throughout the drawings, the same or corresponding components or parts are given the same or corresponding reference numerals, and repeated descriptions are omitted. Furthermore, the drawings are not intended to show relative proportions between components or parts, or between the thicknesses of various layers; therefore, specific thicknesses and dimensions should be determined by those skilled in the art based on the following non-limiting embodiments.

[0016] Figure 1 This is an example of a block diagram illustrating the general configuration of an electron beam device according to an embodiment. For example... Figure 1 As shown, the electron beam device 1 includes an electron microscope 2, a control computer 3, a structural information storage device 4, and an electric field correction diagram storage device 5.

[0017] The electron microscope 2 can be a scanning electron microscope (SEM). As shown in the figure, the electron microscope 2 has a microscope tube 21, a sample chamber 22, an electron gun control unit 23, a lens control unit 24, a deflector control unit 25, a lens control unit 26, an electrode control unit 27, a stage control unit 28, a signal processing unit 29, and an image generation unit 30.

[0018] The microscope tube 21 is equipped with: an electron gun 21G, a condenser lens 21L, a deflector 21D, an objective lens 21O, and a detector 21E. Additionally, the sample chamber 22 is equipped with: a stage 22S that can move at least in the XYZ directions; a support pin 22P disposed on the stage 22S and supporting the sample S to be inspected and measured; a deceleration electrode 22E disposed on the stage 22S at a distance from the sample S supported by the support pin 22P; and a drive mechanism 22D that drives the stage 22S.

[0019] Furthermore, the sample S is, for example, a template used in imprint lithography. Figure 1 As shown, the template has a mesa M and a base B surrounding it. When the template is pressed onto the resist film, the mesa M comes into contact with the resist film. The mesa M protrudes from the base B, thus creating a step difference of, for example, approximately 10–40 μm between the mesa M and the base B in the Z direction.

[0020] The control computer 3 is connected to the electron gun control unit 23, lens control units 24 and 26, deflector control unit 25, electrode control unit 27, stage control unit 28, signal processing unit 29, and image generation unit 30 of the electron microscope 2. Additionally, the structural information storage device 4 and the electric field correction diagram storage device 5 are connected to the control computer 3.

[0021] Furthermore, the storage device 6, display device 7, and input device 8 can also be connected to the control computer 3. The storage device 6 can be implemented using a hard disk drive (HDD), semiconductor memory, or the like. The storage device 6 stores, via input from the control computer 3, information such as electron beam conditions, the type of the pattern being inspected, the coordinate position of the inspection and measurement area, and various thresholds used for inspection and measurement. In addition, the storage device 6 can also store, via input from the control computer 3, image signals generated by the image generation unit 30 of the electron microscope 2.

[0022] The display device 7 can be, for example, a liquid crystal display (LCD) or an organic EL display, which can display a surface image of the sample S based on image signals from the control computer 3. The input device 8 can be, for example, a keyboard or a computer mouse, and may further include an interface device for connecting the control computer 3 to the Internet or a local area network. Through the input device 8, information such as electron beam conditions, the type of pattern being inspected, the coordinates of the inspection area, and various thresholds used for inspection and measurement can be input to the control computer 3.

[0023] Furthermore, the control computer 3 can be implemented as a computer including a CPU, ROM, RAM, etc. Alternatively, the control computer 3 can be implemented using hardware such as application-specific integrated circuits (ASICs), programmable gate arrays (PGAs), and field-programmable gate arrays (FPGAs). The control computer 3 comprehensively controls the electron beam device based on control programs and various data. Specifically, the control computer 3 generates various control signals based on control programs and various data, and sends the generated control signals to the electron gun control unit 23, lens control units 24 and 26, deflector control unit 25, electrode control unit 27, stage control unit 28, signal processing unit 29, and image generation unit 30 of the electron microscope 2. The programs and various data can be downloaded, for example, via wired or wireless means from non-transitory computer-readable storage media such as hard disk drives (HDDs), semiconductor memories, and servers.

[0024] The electron gun control unit 23 is connected to the electron gun 21G inside the lens barrel 21. The electron gun control unit 23 controls the electron gun 21G based on control signals from the control computer 3. Specifically, the electron gun control unit 23 can cause the electron gun 21G to release the electron beam EB (primary electron beam) within a specified period and adjust the intensity of the electron beam EB.

[0025] The lens control unit 24 is connected to the condenser lens 21L. The lens control unit 24 controls the condenser lens 21L based on control signals from the control computer 3. For example, the lens control unit 24 can focus the electron beam EB emitted from the electron gun 21G via the condenser lens 21L.

[0026] The deflector control unit 25 is connected to the deflector 21D. Based on control signals from the control computer 3, the deflector control unit 25 controls the deflector 21D. The deflector controller 25 causes the deflector 21D to generate a deflection electric field or a deflection magnetic field, causing the electron beam EB to deflect in the X and Y directions. Thus, the electron beam EB scans the surface of the sample S.

[0027] The lens control unit 26 is connected to the objective lens 21O. Based on control signals from the control computer 3, the lens control unit 26 controls the objective lens 21O. Specifically, it adjusts the focal position of the electron beam EB so that the focal point of the electron beam EB is aligned with the surface.

[0028] Electrode control unit 27 is connected to deceleration electrode 22E. Electrode control unit 27 controls deceleration electrode 22E based on control signals from control computer 3. A so-called deceleration voltage is applied to deceleration electrode 22E. Deceleration voltage is a voltage applied to stage 22S to decelerate electrons incident on sample S. Decelerating electrons reduces the surface charge of sample S, resulting in a clearer image. The structure of deceleration electrode 22E and the control of deceleration electrode 22E by electrode control unit 27 will be described later.

[0029] The stage control unit 28 is connected to the drive mechanism 22D of the stage 22S. Based on control signals from the control computer 3, the stage control unit 28 moves the stage 22S in the X and Y directions.

[0030] The signal processing unit 29 is connected to the detector 21E and receives the output signal from the detector 21E. After the electron beam EB irradiates the sample S, secondary electrons SE are released from the surface of the sample S. When these secondary electrons SE are incident on the detector 21E, the detector 21E generates a pixel signal corresponding to the number of incident secondary electrons SE. This pixel signal is received by the signal processing unit 29 as an output signal. The signal processing unit 29 performs signal processing on the received signal, such as noise reduction and amplification, performs A / D conversion on the processed signal, and sends the digital signal to the control computer 3. In addition, the signal processing unit 29 can also control the detector 21E based on the control signal from the control computer 3. Specifically, the on / off state and sensitivity of the detector 21E are controlled by the signal processing unit 29 based on the control signal from the control computer 3.

[0031] The image generation unit 30 is connected to the signal processing unit 29 and receives digital signals from the signal processing unit 29. The image generation unit 30 performs prescribed image processing on the received digital signals to generate an image signal. The image signal is sent to the display device 7 via the control computer 3, and a secondary electronic image of the surface of the sample S is displayed on the display device 7. In addition, the image signal can also be sent to the storage device 6 via the control computer 3 and stored therein.

[0032] The structural information storage device 4 can be implemented using a hard disk drive (HDD), semiconductor memory, or the like. The structural information storage device 4 inputs and stores the structural information of the sample S input from the input device 8 via the control computer 3. The structural information may, for example, be the table structure information of the template serving as the sample S. The table structure information includes information on the planar shape and height of the template. That is, the table structure information includes information on the planar shape and height of the table surface M. The table structure information may, for example, include the numbering of multiple grids dividing the surface of the template (the side pressed against the resist film) of the sample S, which is the object of inspection and measurement, and the height associated with that number at that grid. Additionally, the table structure information may also include the coordinate position on the surface of the template, and the surface height associated with that coordinate position at that position.

[0033] Furthermore, the mesa structure information can be CAD data used when designing the mesa structure of the template, or measurement data. It can also be design data for a device pattern that needs to be formed using a template. In this case, the design data can also include data related to the shape of the chip's outer periphery (e.g., the cutout area). When design data containing such data is input from the input device, it can be displayed on the display device 7, and based on this display, it can be processed into mesa structure information. The mesa structure information can be input from the input device 8 and stored in the structure information storage device 4.

[0034] The electric field correction diagram storage device 5 stores the electric field correction diagram calculated by the control computer 3 based on the platform structure information (described later).

[0035] The following is combined Figure 2 (A) and Figure 2 (B) indicates that the deceleration electrode 22E. Figure 2 (A) is a schematic top view showing the deceleration electrode 22E. Figure 2 (B) is a schematic partial perspective view of the cylindrical electrode included in the deceleration electrode 22E.

[0036] like Figure 2 As shown in (A), in this embodiment, the deceleration electrode 22E has a flat electrode portion FE1, a cylindrical electrode portion PE, and a flat electrode portion FE2. Specifically, the flat electrode portion FE1 has a rectangular shape when viewed from above, and the cylindrical electrode portion PE is arranged to surround the flat electrode portion FE1. Furthermore, the flat electrode portion FE2 is arranged to surround the cylindrical electrode portion PE. The flat electrode portions FE1 and FE2 are formed of a metal such as copper and have a flat upper surface. In addition, the flat electrode portions FE1 and FE2 are electrically connected to the electrode control unit 27 and are energized by the electrode control unit 27. Furthermore, under the control of the electrode control unit 27, the flat electrode portions FE1 and FE2 can be energized with the same voltage or with different voltages.

[0037] The columnar electrode portion PE has dimensions comparable to those of the sample S (specifically, the template) to be inspected and measured. Specifically, the columnar electrode portion PE has an outer circumference larger than the outer circumference of the template's mesa M, and an inner circumference smaller than the outer circumference of the mesa M, corresponding to the area where the end of the mesa M is located. Furthermore, the outer surface of the mesa M is not limited to being flat; in some cases, it may have a portion protruding outwards and a portion recessed inwards. In such cases, it is ideal that both the protruding and recessed portions fall within the area of ​​the columnar electrode portion PE.

[0038] In addition, the columnar electrode section PE has multiple columnar electrodes P. Figure 2(B) is a schematic partial perspective view of the upper end (the end facing the sample S) of the cylindrical electrode P. Figure 2 As shown in (B), the cylindrical electrode P comprises a cylindrical body PP with a cylindrical shape and an insulating film PI covering the outer peripheral surface of the cylindrical body PP. The cylindrical body PP can be formed of a metal such as copper. A wire (not shown) is connected to the lower end of the cylindrical body PP, through which the cylindrical electrode P is electrically connected to the electrode control unit 27. Thus, voltage is applied individually to the cylindrical electrode P from the electrode control unit 27. Furthermore, the insulating film PI is provided to prevent electrical short circuits between two adjacent cylindrical electrodes P. The insulating film PI can be formed of a resin material, for example. In the illustrated example, a portion of the upper end of the outer peripheral surface of the cylindrical body PP is exposed, but the insulating film PI may also cover the entire outer peripheral surface of the cylindrical body PP.

[0039] Furthermore, the diameter of the columnar electrode P is ideally, for example, less than 1 mm. Alternatively, copper columnar electrodes used in flip chip manufacturing processes can be used as the columnar electrode P; flip chip manufacturing is a method of electrically connecting the semiconductor chip to the electrodes of the package when housing a semiconductor chip within a package. This allows the diameter of the columnar electrode P to be less than 50 μm and its height to be more than 100 μm. The smaller the diameter of the columnar electrode P, the more precise the electric field correction can be performed.

[0040] In addition, Figure 1 In this design, the deceleration electrode 22E is mounted on the stage 22S, but it can also be integrated with the stage 22S. However, the dimensions of the deceleration electrode 22E (especially the size and shape of the columnar electrode portion PE) will vary depending on the shape of the sample S, so it is ideal to form it separately from the stage 22S for easy replacement.

[0041] Next, the image acquisition method according to the embodiment will be described. This image acquisition method can be implemented using the electron beam device 1 described above. Figure 3 This is a flowchart illustrating the image acquisition method described herein. It is assumed that the sample S (template), which is the object of this method, is supported on stage 22S within the electron beam apparatus 1, and the electron microscope 2 is ready.

[0042] First, in step S1, the platform structure information of the template stored in the structural information storage device 4 is read by the control computer 3. As described above, the platform structure information includes information on the planar shape and height of the platform surface. Next, in step S2, electric field correction data is generated using the read platform structure information. An example of the generation of electric field correction data will be described below.

[0043] Figure 4 (A) is a schematic diagram showing the structure of the template TP, which serves as the specimen S, as specified by the platform structure information. Figure 4(B) is a graph that displays the electric field correction data calculated using the platform structure information as an electric field correction diagram. Additionally, Figure 4 In (A), the base portion B is omitted (see reference). Figure 1 The diagram shows the figure. Furthermore, according to the platform structure information in this embodiment, the height difference between the platform surface M and the base portion is 30 μm, but it is not limited to this. Additionally, the template TP is formed of a dielectric material such as quartz glass.

[0044] Suppose a template TP is supported with its back side in contact with the upper surface of a metal plate. When a voltage is applied to the plate, a charge with the opposite polarity to the applied voltage will be induced on the surface of the template TP. The induced charge tends to concentrate at the edge (or corner) of the isthmus M. This is because the charge is less likely to repel at the edge, and even if it does, it cannot move further away from the edge. That is, if a step difference exists due to the isthmus M, as in the template TP, the distribution of the induced charge will be uneven. If this unevenness occurs, the deceleration voltage cannot be applied uniformly, and the uniform deceleration of electrons incident on the template TP will be hindered.

[0045] Figure 4 The electric field correction diagram shown in (B) was created to correct this charge distribution. That is, based on the information about the platform structure, such as by determining the position and height of the edge of the platform M, the charge distribution is estimated, and based on the estimation results, the distribution of the applied voltage that can make the charge distribution uniform can be determined. Figure 4 In (B), the distribution of the applied voltage is represented by contour lines C1 to C3. The illustrated example shows that the applied voltage should be reduced in the following order: the region inside contour line C1, the region between contour lines C1 and C2, and the region between contour lines C2 and C3. That is, the edge of the isthmus M of the template TP can be considered to be located in the region between contour lines C2 and C3. By making the voltage applied to this region lower than that in other regions, the charge induced near the edge of the isthmus M can be reduced, thereby making the charge distribution on the surface of the template TP more uniform.

[0046] Furthermore, electric field correction diagrams can be generated, for example, using the three-dimensional finite element method (FEM). The finite element method (FEM) is a numerical method for solving differential equations under certain boundary conditions. It represents structures using sets of small polygons called "elements," thus making it applicable to structures with complex shapes. It can numerically obtain the boundary value solutions of differential equations under given boundary conditions. Alternatively, electric field correction diagrams can also be generated using a specified simulator.

[0047] Back to Figure 3In step S3, the control computer 3 selects the cylindrical electrode P of the deceleration electrode 22E based on the electric field correction diagram and calculates the voltage to be applied to the selected cylindrical electrode P. The control computer 3 sends a control signal, including the selected cylindrical electrode P and its applied voltage, to the electrode control unit 27. This control signal may include, for example, a reference deceleration voltage applied to the flat plate electrode units FE1 and FE2 and the unselected cylindrical electrode P, and the difference between the voltage to be applied to the selected cylindrical electrode P and the reference deceleration voltage.

[0048] Next, in step S4, the electrode control unit 27 applies a deceleration voltage to the deceleration electrode 22E. At this time, a predetermined voltage is applied to the selected columnar electrode P within the columnar electrode unit PE. As a result, a locally differentiated voltage is applied to the template TP. Therefore, for example, the concentration of charge at, for example, the edge of the isthmus M can be counteracted, and a uniform electric field is generated on the surface of the template TP.

[0049] Next, in step S5, the electron gun control unit 23 releases the electron beam EB from the electron gun 21G based on the control signal from the control computer 3. Furthermore, under the action of the deflector control unit 25, the electron beam EB scans the template TP, and the image (SEM image) formed by secondary electrons released from the surface of the template TP is acquired by the detector 21E. This concludes the series of processing steps.

[0050] As explained above, according to the electron beam apparatus and image acquisition method of the embodiment, a predetermined columnar electrode of the deceleration electrode is selected based on the electric field correction map generated based on the table structure information, and a predetermined voltage is applied to the selected columnar electrode, thereby making the electric field distribution on the template surface more uniform. Thus, the electron beam can be uniformly incident on the template surface, and an image that accurately reflects the shape of the template surface can be acquired.

[0051] In addition, the above combination Figure 3 This explains the image acquisition method. Figure 3The series of processing steps shown can be implemented as part of a measurement method or inspection method. For example, when measuring the dimensions of a specific part in an acquired image, reducing noise by repeatedly acquiring images of that part can improve measurement accuracy. That is, after step S5, steps such as repeatedly acquiring images of a specific part, reducing noise based on repeatedly acquired images, and measuring dimensions based on images with reduced noise can be added. Furthermore, for example, when performing defect inspection of a template TP, it is not necessary to repeatedly acquire images. However, steps such as determining the shape of the tabletop M (the position of the edge, etc.) based on the image and comparing it with the tabletop structure information can be set. Even when the above method is implemented as a measurement method or inspection method, high-precision measurement and inspection can be performed because an image that accurately reflects the shape of the template surface can be acquired.

[0052] (Modified Example)

[0053] The electron beam apparatus according to the modified embodiment will now be described. The difference between the modified electron beam apparatus and the electron beam apparatus 1 according to the embodiment is that it has a deceleration electrode different from the deceleration electrode 22E; the other configurations are the same as those of the electron beam apparatus 1 according to the embodiment. The modified electron beam apparatus will be described below focusing on the differences.

[0054] Figure 5 (A) is a schematic top view showing the deceleration electrode of the electron beam device involved in the modified example. Figure 5 (B) is along Figure 5 A partial sectional view of line L1-L1 in (A). For example... Figure 5 As shown in (A), the deceleration electrode 220E is identical to the deceleration electrode 22E when viewed from above. However, as Figure 5 As shown in (B), the cylindrical electrodes P0 of the deceleration electrode 220E can move up and down individually under the action of the drive mechanism (not shown). Therefore, the interval between each cylindrical electrode P0 and the sample S can be adjusted for each cylindrical electrode P0. In addition, when each cylindrical electrode P0 moves upward, it can also contact the back side of the sample S (template) supported by the support pin 22P.

[0055] Furthermore, similar to the columnar electrodes P, each columnar electrode P0 has, for example, a metal cylinder PP and an insulating film PI around it. A wire (not shown) is also connected to the lower end of the cylinder PP, through which it is electrically connected to the electrode control unit 27. Thus, the columnar electrodes P0 can also be individually voltageed by the electrode control unit 27.

[0056] As described above, the distance between the back side of the sample S and the columnar electrode P0 can be adjusted, thus enabling more precise adjustment of the electric field distribution on the surface of the template TP.

[0057] Next, an image acquisition method (inspection method, measurement method) implemented using the electron beam apparatus involved in the modified example will be described. Figure 6 This is a flowchart illustrating an image acquisition method implemented using an electron beam apparatus according to a variation of the embodiment.

[0058] Steps S21 and S22 are respectively with Figure 3 Steps S1 and S2 in the flowchart are the same. That is, the platform structure information is read in step 21, and an electric field correction diagram is generated in step S22. Then, in step S23, the control computer 3, based on the electric field correction diagram, selects, for example, the cylindrical electrode P0 of the deceleration electrode 220E, and calculates the voltage to be applied to the selected cylindrical electrode P0 and the moving distance of the selected cylindrical electrode P0. A control signal containing such information is sent from the control computer 3 to the electrode control unit 27.

[0059] Then, in step S24, the determined voltage is applied to the selected cylindrical electrode P0, and in step S25, the selected cylindrical electrode P0 is moved by the determined moving distance. Alternatively, the order of steps S24 and S25 can be reversed, or they can be performed simultaneously.

[0060] Next, in step S26, the electron gun control unit 23 releases the electron beam EB from the electron gun 21G based on the control signal from the control computer 3. Furthermore, under the action of the deflector controller 25, the electron beam EB scans the template TP, and an image (SEM image) formed by secondary electrons SE released from the surface of the template TP is acquired. This concludes the series of processing steps.

[0061] As explained above, according to the image acquisition method (inspection method, measurement method) implemented using the electron beam device involved in the modified example, when a voltage is applied to the deceleration electrode 220E according to the electric field correction diagram made based on the table structure information, the distance between the columnar electrode P0 of the columnar electrode part PE and the back surface of the template TP can be adjusted, thus enabling the electric field distribution on the surface of the template TP to be adjusted with higher precision.

[0062] Furthermore, for example, an equal voltage can be applied to the entirety of the flat plate electrode portions FE1 and FE2 and the cylindrical electrode portion PE, while adjusting the electric field distribution by moving the cylindrical electrode P0 up and down. In other words, in step S23, the voltage to be applied to the selected cylindrical voltage P0 can also be determined to be equal to the voltage applied to other portions of the deceleration electrode 220E.

[0063] The foregoing has described several embodiments of the present invention, which are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention described in the patent claims and its equivalents.

[0064] For example, in the aforementioned deceleration electrodes 22E and 220E, a flat plate electrode portion FE1 is provided inside the columnar electrode portion PE, but the flat plate electrode portion FE1 may be omitted and columnar electrodes P and P0 may be provided instead. As a result, in a template having a three-dimensional structure, for example, the uneven distribution of the electric field caused by step differences can be reduced not only at the edge of the platform surface M, but also at the inner side of the platform surface.

[0065] Furthermore, the columnar electrodes P and P0 are not limited to having a cylindrical shape PP, but can also be prisms such as quadrilaterals or hexagons. In this case, an insulating film PI is provided around the prism.

Claims

1. An electron beam apparatus that acquires an image of a sample by irradiating it with an electron beam, the electron beam apparatus comprising: The support portion supports the sample; An electrode, disposed below the sample supported by the support portion, is capable of applying a voltage to the sample, the electrode comprising a plurality of columnar electrodes capable of independently setting the voltage; as well as The control unit is capable of generating correction data for correcting the electric field distribution generated on the sample based on structural information representing the structure of the sample, and controlling the plurality of columnar electrodes based on the correction data.

2. The electron beam apparatus according to claim 1, characterized in that, The sample has a planar portion and a raised portion that rises from the planar portion, and the plurality of columnar electrodes are disposed corresponding to the raised portion.

3. The electron beam apparatus according to claim 1 or 2, characterized in that, Each of the plurality of columnar electrodes is movable relative to the sample.

4. The electron beam apparatus according to claim 1, characterized in that, The structural information includes information about the planar shape and height of the specimen.

5. The electron beam apparatus according to claim 1, characterized in that, Each of the plurality of columnar electrodes has a columnar body formed of a conductive material and a film made of an insulating material covering the outer peripheral surface of the columnar body.

6. An image acquisition method, comprising: Based on structural information representing the structure of the sample, correction data is generated to correct the electric field distribution generated on the sample. Based on the correction data, locally differentiated voltages are applied to the sample, and the sample is irradiated with electrons. The application of the locally varying voltages is performed by a plurality of columnar electrodes positioned below the sample and capable of independently setting the voltage.

7. The image acquisition method according to claim 6, characterized in that, The structural information includes information about the planar shape and height of the specimen.

8. The image acquisition method according to claim 6, characterized in that, Each of the plurality of columnar electrodes is individually subjected to a voltage.

9. The image acquisition method according to claim 6, characterized in that, The spacing between the plurality of columnar electrodes and the sample is adjusted.

Images