Multi-charged particle beam evaluation method, multi-charged particle beam evaluation program, multi-charged particle beam drawing method, and multi-charged particle beam irradiation device aperture array substrate inspection method

Abstract

To improve the accuracy of writing by identifying an individual beam or a beam area where a change in angle of a beam trajectory in the vicinity of a shaping aperture array substrate occurs.SOLUTION: Provided is a multi charged particle beam evaluation method for evaluating trajectories of a plurality of individual beams in a multi charged particle beam which has passed through a plurality of openings provided in an aperture array substrate. The method includes: measuring the positions of the plurality of individual beams at each of a plurality of heights (a first height and a second height different from the first height), in an optical axis direction, of an imaging plane of the multi charged particle beam, or a measurement plane on which a mark for beam position measurement is formed; and extracting a singular beam in which a beam trajectory has changed among the plurality of individual beams, based on a position difference, the position difference being a difference between a beam position measured at the first height and a beam position measured at the second height of each of the plurality of individual beams.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating a multi-charged particle beam, a multi-charged particle beam writing method, and a method for inspecting an aperture array substrate for a multi-charged particle beam irradiation device. [Background technology]

[0002] As LSIs become more highly integrated, the circuit line width required for semiconductor devices is becoming finer every year. To form the desired circuit pattern on a semiconductor device, a method is adopted in which a high-precision master pattern formed on quartz is reduced and transferred onto a wafer using a reduction projection exposure system. The high-precision master pattern is drawn using an electron beam drawing system, and so-called electron beam lithography technology is used.

[0003] For example, there is a lithography system that uses multiple beams. Compared to lithography using a single electron beam, using multiple beams allows for the irradiation of many beams at once, thereby significantly improving throughput. In a multi-beam lithography system, for example, an electron beam emitted from an electron gun passes through a shaping aperture array (SAA) substrate with multiple apertures to form multiple beams, and each beam is individually blanked and controlled by a blanking aperture array (BAA) substrate. The unblocked beams are reduced in size by an optical system and deflected by a deflector to be irradiated at the desired position on the sample.

[0004] In multi-beam lithography systems, dust and contamination (dirt generated by beam irradiation) adhering to the SAA substrate can become charged, causing deflections that were not anticipated in the electron optical design, which can cause the trajectories of some of the multi-beams to bend at angles different from the design. Hereinafter, this change in the angle of the beam trajectory near the SAA substrate will be referred to as the SAA angle deviation.

[0005] Because the SAA substrate and BAA substrate are placed close to each other, this SAA angle deviation can be caused by charging of dust or contaminants on the BAA substrate, or by charging of exposed insulators or attached foreign particles due to manufacturing process instabilities. Aperture array substrates, such as SAA substrates and BAA substrates, used in multi-beam lithography systems have a huge number of minute apertures and complex electrode structures, e.g., 512 columns x 512 rows, totaling more than 260,000. It is therefore difficult to detect all of these attached or exposed dust or insulators through prior inspection, such as observation or analysis. While inspection technologies for large-scale (very numerous) microstructures have advanced with the development of LSI technology, the final pass / fail criterion for aperture array substrate inspection is whether or not the electron beam trajectory is affected when it is cut or passed nearby. This issue cannot be fully addressed by conventional inspection technologies for electronic circuits, and conventional LSI inspection technologies have not been able to adequately address this issue.

[0006] SAA angle deviation causes distortion and aberration of the multi-beams on the imaging surface (sample surface), resulting in reduced imaging accuracy. Previously, it was not possible to measure SAA angle deviation for each individual beam, which hindered improvements in imaging accuracy. Another problem was that it was impossible to completely detect local defects on SAA and BAA substrates that cause SAA angle deviation (such as dust adhesion, structures or materials that are prone to contamination, exposed insulators, or foreign matter adhesion). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-140643 [Patent Document 2] Japanese Patent Publication No. 2020-205314 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-266525 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a method for evaluating a multi-charged particle beam and a multi-charged particle beam writing method that can identify individual beams or beam regions where an angle change of the beam trajectory occurs near a shaping aperture array substrate and improve writing accuracy. Another aim of the present invention is to provide a method for inspecting an aperture array substrate for a multi-charged particle beam irradiation device that can reliably detect local defects (such as dust adhesion, structure or material that is prone to adhesion of contamination, exposed insulator, or foreign matter adhesion) on the aperture array substrate (SAA substrate and BAA substrate) that cause angle changes. [Means for solving the problem]

[0009] A method for evaluating a multi-charged particle beam according to one aspect of the present invention is a method for evaluating the trajectories of a plurality of individual beams in a multi-charged particle beam that has passed through a plurality of openings provided in an aperture array substrate, in which the height in the optical axis direction of an imaging plane of the multi-charged particle beam or a measurement plane on which a mark for beam position measurement is formed is set to a first height and a second height different from the first height, and the positions of the plurality of individual beams are measured, and a singular beam whose beam trajectory has changed is extracted from the plurality of individual beams based on a position difference between the beam position measured at the first height and the beam position measured at the second height for each of the plurality of individual beams.

[0010] A multi-charged particle beam writing method according to one aspect of the present invention writes a pattern on a substrate using beams other than the singular beam extracted by the evaluation method of the present invention, out of the multi-charged particle beams that have passed through a plurality of openings provided in the aperture array substrate.

[0011] A method for inspecting an aperture array substrate for a multi-charged particle beam irradiation apparatus according to one aspect of the present invention inspects the aperture array substrate using position information of the specific beam extracted by the evaluation method of the present invention. [Effects of the Invention]

[0012] According to the present invention, by identifying individual beams or beam regions where an angular change in the beam trajectory occurs near a shaping aperture array substrate, it is possible to improve drawing accuracy and improve inspection efficiency of aperture array substrates. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram of a drawing device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a shaped aperture array substrate. [Figure 3] 10 is a flowchart illustrating a method for evaluating multiple charged particle beams according to the embodiment. [Figure 4] 10(a) and 10(b) are diagrams showing an example of a change in height when measuring the amount of positional deviation of an individual beam. [Figure 5] FIG. 10 is a diagram illustrating an example of a beam position difference. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the following embodiments, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and a beam using charged particles such as an ion beam may also be used. Furthermore, in the embodiments, a multi-beam lithography system using multiple electron beams will be described as an example of a multi-charged particle beam irradiation system. However, the multi-charged particle beam irradiation system is not limited to a multi-beam lithography system, and the present embodiments can also be applied to a multi-beam inspection system.

[0015] Fig. 1 is a schematic diagram of a multi-beam lithography apparatus according to an embodiment of the present invention. As shown in Fig. 1, the multi-beam lithography apparatus includes a lithography unit W and a control unit C. The lithography unit W includes an electron optical column 102 and a lithography chamber 103. Inside the electron optical column 102, there are arranged an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array substrate 204, a limiting aperture substrate 206, a deflector 208, and an objective lens 210, which constitute the electron optical system of the multi-beam lithography apparatus.

[0016] An XY stage 105 movable in the X and Y directions and a detector 220 are arranged in the patterning chamber 103. The XY stage 105 may be movable in the Z direction. A substrate 10 to be patterned is arranged on the XY stage 105. The substrate 10 includes an exposure mask used in manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured, and the like. The substrate 10 also includes a mask blank coated with resist and on which nothing is yet patterned.

[0017] A mark 20 for measuring the beam position is also provided on the XY stage 105. The mark 20 is, for example, a cross-shaped metallic mark. A detector 220 detects reflected electrons (or secondary electrons) when the mark 20 is scanned with the beam.

[0018] In addition, a mirror 30 for measuring the position of the stage is placed on the XY stage 105.

[0019] The control unit C has a control computer 110, a control circuit 120, a detection circuit 122, and a stage position detector 124. The stage position detector 124 irradiates a laser, receives the light reflected from the mirror 30, and detects the position of the XY stage 105 based on the principle of laser interferometry.

[0020] FIG. 1 shows the configuration necessary for explaining the embodiment, and other configurations are omitted from the illustration.

[0021] 2 is a conceptual diagram showing the configuration of a shaping aperture array (SAA) substrate 203. In FIG. 2, apertures (first openings) 203a are formed in a matrix of p columns (y direction) by q rows (x direction) (p, q≧2) at a predetermined arrangement pitch on the shaping aperture array substrate 203. For example, 512 columns by 512 rows of apertures 203a are formed. Each aperture 203a is formed as a rectangle with the same dimensions. The apertures 203a may also be circular. Multibeams MB are formed when portions of the electron beam 200 pass through each of these multiple apertures 203a.

[0022] The blanking aperture array substrate 204 is provided below the shaping aperture array substrate 203, and has passage holes (second openings) formed in alignment with the positions of the apertures 203a of the shaping aperture array substrate 203. A blanker consisting of a pair of two electrodes is disposed in each passage hole. One electrode of the blanker is fixed at ground potential, and the other electrode is switched between ground potential and another potential. The electron beams passing through each passage hole are deflected independently by the voltage applied to the blanker. In this way, the multiple blankers perform blanking deflection on the corresponding beams among the multi-beams MB that have passed through the multiple apertures 203a of the shaping aperture array substrate 203.

[0023] An electron beam 200 emitted from an electron gun 201 (emitter) is refracted by an illumination lens 202 and illuminates the entire shaping aperture array substrate 203. The electron beam 200 illuminates an area including multiple (all) apertures 203a. A portion of the electron beam 200 passes through the multiple apertures 203a in the shaping aperture array substrate 203, thereby forming multiple electron beams (multi-beams MB). The multi-beams MB pass through corresponding blankers in a blanking aperture array substrate 204. The blankers perform blanking control on the passing beams so that the beams are in an ON state for a set writing time (irradiation time).

[0024] The multi-beams MB that have passed through the blanking aperture array substrate 204 are refracted by the illumination lens 202 and travel toward the opening (third opening) formed in the center of the limiting aperture substrate 206. The multi-beams MB then form a crossover at the height position of the opening of the limiting aperture substrate 206.

[0025] Here, the beams deflected by the blankers of the blanking aperture array substrate 204 are displaced from the openings of the limiting aperture substrate 206 and are blocked by the limiting aperture substrate 206. On the other hand, the beams not deflected by the blankers of the blanking aperture array substrate 204 pass through the openings of the limiting aperture substrate 206. In this way, the limiting aperture substrate 206 blocks the beams deflected by the blankers to be in the beam OFF state.

[0026] Each beam of one shot is formed by the beams that have passed through the limiting aperture substrate 206 from when the beam is turned on until when it is turned off. Each beam of the multi-beam MB that has passed through the limiting aperture substrate 206 is turned by the objective lens 210 into an aperture image of the opening 203a of the shaping aperture array substrate 203 at a desired reduction magnification, and is focused on the substrate 10. Then, the beams that have passed through the limiting aperture substrate 206 (the entire multi-beam) are deflected collectively in the same direction by the deflector 208, and each beam is irradiated onto its respective irradiation position on the substrate 10.

[0027] For example, when the XY stage 105 is moving continuously, the deflector 208 controls the beam irradiation position so that it follows the movement of the XY stage 105. Ideally, the multiple beams MB irradiated at one time are arranged at a pitch obtained by multiplying the arrangement pitch of the multiple apertures 203a in the shaping aperture array substrate 203 by the desired reduction ratio described above. The drawing device performs drawing operations using a raster scan method in which shot beams are irradiated continuously in order, and when drawing a desired pattern, unnecessary beams are turned off by blanking control.

[0028] In such a lithography device, dust and contamination adhering to the shaping aperture array substrate 203 can become charged, causing deflection that was not anticipated in the electron-optical design, and an "SAA angle deviation" can occur in some of the multi-beams, where the beam trajectory is bent at an angle different from the design angle near the shaping aperture array (SAA) substrate 203. This SAA angle deviation can also be caused by charging of dust and contamination adhering to the blanking aperture array substrate 204, or by charging of exposed insulators or attached foreign matter due to instability in the manufacturing process.

[0029] It is necessary to identify beams that have an SAA angle deviation in order to improve the accuracy of pattern writing on the substrate 10. A multi-beam evaluation method for identifying beams that have an SAA angle deviation will be described with reference to the flowchart shown in FIG.

[0030] First, at two different heights (first height z1 and second height z2) near the drawing surface, the positions of multiple individual beams among the many individual beams constituting the multibeam are measured (steps S1 and S2). Here, the beam position refers to the beam incident position on a measurement surface perpendicular to the optical axis, and is usually expressed as a pair of x- and y-coordinate values ​​within the measurement surface. For example, only the individual beams to be measured are turned on one by one in sequence, and the beams are deflected by the deflector 208 to scan the mark 20, and the electrons reflected by the mark 20 are detected by the detector 220. The detection circuit 122 notifies the control computer 110 of the amount of electrons detected by the detector 220. The control computer 110 obtains a scan waveform from the detected electron amount and determines the position of the individual beam based on the position of the XY stage 105.

[0031] The individual beams are switched on in order to determine the position of each beam. There is no particular limit to the number of individual beams whose positions are to be determined, but for example, 7 x 7 equally spaced beams are selected as measurement targets from the 512 x 512 beams that make up the multi-beam.

[0032] Note that the "different height" or "changing the height" may refer to "changing the measurement surface height and fixing the image surface height" as shown in FIG. 4(a), in which the XY stage 105 is moved in the Z direction (the optical axis direction or the beam traveling direction) to change the height of the surface (measurement surface) of the mark 20 in the optical axis direction while fixing the height of the multi-beam imaging surface. Alternatively, it may refer to "fixing the measurement surface height and changing the image surface height" as shown in FIG. 4(b), in which the height of the measurement surface is not changed but the height of the multi-beam imaging surface in the optical axis direction is changed. In this case, if the objective lens 210 constituting the electron optical system of the drawing apparatus is a magnetic lens, the height of the multi-beam imaging surface can be changed by changing the excitation of the objective lens 210 using the control circuit 120. If the objective lens 210 is an electrostatic lens, the applied voltage can be changed. Instead of the objective lens, the applied voltage of, for example, an electrostatic focus correction lens (not shown) disposed between the deflector 208 and the mark 20 may be changed.

[0033] In this way, the height of the imaging plane of the multi-beam can be changed by changing the excitation amount (excitation for a magnetic lens, applied voltage for an electrostatic lens) of the lens (objective lens, focus correction lens, etc.) arranged in the optical axis direction between the shaping aperture array substrate 203 and the mark 20. Note that the height of the imaging plane may also be changed by changing the excitation amount of multiple lenses at a fixed ratio.

[0034] The difference between the two heights z1 and z2 is preferably several μm to several tens of μm. The origin of the height coordinate z may be determined in any way as long as it is constant during the execution of the method of the present application. Note that at heights z1 and z2, the beam does not need to be just focused on the surface (measurement surface) of mark 20. For example, the beam may be just focused at one height and out of focus at the other height, or it may be out of focus at both heights.

[0035] For each beam, the difference (position difference) between the position at the first height z1 and the position at the second height z2 is calculated (step S3). The position difference is calculated for each of the x coordinate value and the y coordinate value.

[0036] The position difference of each beam is plotted as a deviation from the normal position, and beams with anomalous position differences are extracted (step S4). A anomalous position difference means, for example, that the absolute value and / or direction of the position difference is significantly different (a predetermined value or more) from the surrounding beams. For example, Beams with large positional differences, beams at locations where the positional difference changes significantly, beams at locations where the direction of the positional difference changes, and beams at locations where the direction of the positional difference changes are extracted as peculiar beams. Figure 5 shows an example of beams with peculiar positional differences. The extraction of beams with peculiar positional differences may be performed by the control computer 110 or by an operator visually.

[0037] A beam with an SAA angular deviation will have a beam trajectory within the objective lens 210 that is separate from surrounding beams without an SAA angular deviation.

[0038] When the excitation of the objective lens 210 is changed using the above-mentioned "fixed measurement plane height / changed image plane height," the focusing force on each beam within the objective lens 210 changes, causing the beam position on the measurement plane to move. This movement of the beam position is continuous and gradual for beams without SAA angular deviation, but beams with SAA angular deviation follow a trajectory separate from surrounding beams without SAA angular deviation, and therefore exhibit a different tendency. Therefore, by extracting beams whose positions change specifically in response to changes in the objective lens excitation, it is possible to identify beams with SAA angular deviation.

[0039] Because the beam travels essentially straight near the image plane, changing the height of the plane on which the beam position is measured using the "Changing Measurement Plane Height / Fixing Image Plane Height" method described above causes the beam position to move within the measurement plane. This beam position movement is continuous and gradual for beams without SAA angle deviations. However, beams with SAA angle deviations enter from a location farther away from the surrounding beams without SAA angle deviations, resulting in a large change in the angle of incidence at the image plane. As a result, they exhibit a different tendency in beam position movement. Therefore, by extracting beams whose position changes specifically in response to changes in the beam position measurement plane height, it is possible to identify beams with large changes in the angle of incidence at the image plane, i.e., beams with SAA angle deviations.

[0040] The beams having the SAA angle deviation thus identified are excluded, and a pattern is written on the substrate 10 using the writing device. First, the control computer 110 reads the writing data from a storage device (not shown), and performs multiple stages of data conversion processing on the writing data to generate shot data specific to the device. The shot data defines the dose and irradiation position coordinates of each shot, etc.

[0041] The control computer 110 outputs the dose for each shot to the control circuit 120 based on the shot data. The control circuit 120 calculates the irradiation time t by dividing the input dose by the current density. Then, when performing the corresponding shot, the control circuit 120 controls the deflection voltage applied to the corresponding blanker so that the beam is turned on for the irradiation time t. The control circuit 120 turns off the beam if an SAA angle deviation occurs.

[0042] The control computer 110 outputs deflection position data to the control circuit 120 so that each beam is deflected to the position (coordinates) indicated by the shot data. The control circuit 120 calculates the amount of deflection and applies a deflection voltage to the deflector 208. As a result, the multiple beams shot in that round are deflected collectively.

[0043] By not using a beam with an SAA angle deviation, it is possible to improve the drawing accuracy.

[0044] In the above embodiment, when a beam having an SAA angle deviation is identified, it may be assumed that multiple beams within a region of a predetermined size centered on the identified beam have an SAA angle deviation, and the beams within this region may not be used.

[0045] By recording the position within the beam array where the SAA angle deviation occurs and then inspecting the corresponding area of ​​the shaping aperture array substrate 203 by observation, analysis, etc. after disassembling the electron optical column 102, the cause of the dust or charging can be efficiently identified. As a result, countermeasures can be taken promptly, and the quality of the shaping aperture array substrate can be improved quickly. Furthermore, by inspecting the corresponding area of ​​the blanking aperture array substrate 204 by observation, analysis, etc., it is possible to efficiently confirm the exposed insulator, the adhesion of foreign matter, etc., and identify the cause. As a result, countermeasures can be taken promptly, and the quality of the blanking aperture array substrate can be improved quickly.

[0046] In this way, it is possible to reliably and efficiently narrow down the defective areas that actually affect the beam trajectory from a very large number of micro-apertures and micro-electrode structures (for example, more than 260,000), which greatly improves the efficiency of identifying the cause of the defect and taking measures, accelerates quality improvements to the aperture array substrate, and contributes to improved device reliability and extended maintenance intervals.

[0047] In the above embodiment, an example has been described in which the position difference is plotted as a deviation from the normal position and a beam with a unique position difference is extracted, but the position difference measurement value may be approximated by a position polynomial, and all or part of the low-order polynomial components of the approximate polynomial, such as zeroth order, first order, second order, or third order, may be subtracted from the original position difference measurement value to remove components with gradual changes. This emphasizes local changes in the position difference between beams, making it easy to identify beams with SAA angle deviations.

[0048] The position difference may be differentiated between beams or differentiated to a second or higher order, and the resulting value may be used. The value obtained in this way emphasizes local changes in the position difference, making it easier to compare the position difference between beams. Note that, since the difference between adjacent beams is usually substantially equivalent to a differential, the differential process also includes a differential process.

[0049] A threshold value may be set for the position difference measurement value, the value obtained by removing low-order polynomial components, or the value obtained by performing differentiation, and beams (beam regions) whose absolute values ​​are equal to or greater than the threshold value may be selected to identify beams in which an SAA angle deviation has occurred. Note that the calculation process for emphasizing local changes in the position difference is not limited to removing low-order polynomial components or differentiating.

[0050] In the above embodiment, an example has been described in which a beam with a unique position difference is extracted, but a value obtained by dividing the position difference by the height difference Δz (=z2-z1) may also be used. The height difference is the height difference of the imaging plane of the multi-beam, or the height difference of the surface (measurement surface) of the mark 20. Alternatively, a value obtained by dividing the position difference by the height difference Δz and then by the angular magnification of the shaping aperture array substrate 203 may also be used. The value obtained in this manner is converted into an amount equivalent to the angle change in the vicinity of the shaping aperture array substrate 203, and is therefore suitable for comparing and examining the degree of angle change across measurement times and target devices.

[0051] In the above embodiment, an example in which the beam position is measured at two heights (z1, z2) has been described, but the beam position may also be measured at three or more heights. By calculating the rate of change of the beam position relative to the imaging plane height or the measurement plane height, an amount equivalent to the value obtained by dividing the position difference by the height difference Δz can be obtained.

[0052] The beam position measured by simply shifting the objective lens excitation or mark height from just focus may also be used as the position difference. This is because distortion caused by angle changes near the shaping aperture array substrate 203 is usually relatively small on the just focus image plane, so the beam position measured by shifting the objective lens excitation or mark height from just focus will be close to the difference between the beam position measured at just focus objective lens excitation or mark height. This method has the advantage of being simple, although it is slightly less accurate.

[0053] In the above embodiment, the height was set first and the beam position was measured while maintaining the height, but it is also possible to set the beam whose position is to be measured first, change the height while maintaining the height, and measure the beam position at a different height.

[0054] Instead of measuring the beam position, the distortion of the overall beam shape of the multi-beam may be measured, and the beam in which the SAA angle deviation occurs may be identified from the change in the distortion.

[0055] In the above embodiment, the position of each individual beam was measured by scanning the mark 20 with multiple beams and measuring the reflected electrons, but the position of each individual beam may also be determined by drawing a test pattern on the substrate and measuring the position of the drawn pattern with a measuring instrument.

[0056] Each step of the above multi-beam evaluation method is executed by the control computer 110 controlling the control circuit 120, the detection circuit 122, and the stage position detector 124 to operate each part of the drawing unit W. The control computer 110 may be configured with hardware such as an electric circuit, or may be configured with software. When configured with software, a program that realizes at least some of the functions of the control computer 110 may be stored in a recording medium and read and executed by a computer including an electric circuit.

[0057] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0058] 10 Substrate 20 marks 102 Electron Optical Tube 103 Drawing room 105 XY stage 110 Control computer 120 control circuit 200 electron beam 201 Electron Gun 202 Lighting lens 203 Shaped Aperture Array Substrate 204 Blanking aperture array substrate 206 Limiting Aperture Substrate 208 Deflector 210 objective lens

Claims

1. A method for evaluating a multi-charged particle beam, which evaluates trajectories of a plurality of individual beams in a multi-charged particle beam that has passed through a plurality of openings provided in an aperture array substrate, comprising: measuring the positions of the individual beams by setting the height of an image plane of the multi-charged particle beam or a measurement plane on which a mark for beam position measurement is formed in the optical axis direction to a plurality of different heights; A method for evaluating a multi-charged particle beam, which extracts a singular beam from among the plurality of individual beams whose beam trajectory has changed based on a position difference, which is a difference between the beam positions of each of the plurality of individual beams measured at the plurality of heights.

2. 2. The method for evaluating a multi-charged particle beam according to claim 1, wherein the height in the optical axis direction is a height of the image forming plane in the optical axis direction, and the image forming plane is set to each of the plurality of heights by changing an excitation amount of a lens arranged between the aperture array substrate and the mark in the optical axis direction while keeping the measurement plane constant.

3. 2. The method for evaluating a multi-charged particle beam according to claim 1, wherein the height in the optical axis direction is a height of the measurement surface in the optical axis direction, and the measurement surface is set to each of the plurality of heights by moving the measurement surface in the optical axis direction while keeping the image plane constant.

4. 4. The method for evaluating a multi-charged particle beam according to claim 1, further comprising: approximating the position difference by a polynomial; and extracting the singular beam based on a value obtained by subtracting a predetermined low-order component of the polynomial from a measurement value of the position difference.

5. 4. The method for evaluating multiple charged particle beams according to claim 1, wherein the anomalous beam is extracted based on a value obtained by performing a differential process or a second-order or higher differential process on the position difference.

6. A method for evaluating a multi-charged particle beam described in any one of claims 1 to 3, wherein the singular beam is extracted based on the value obtained by dividing the position difference by the corresponding height difference.

7. The plurality of different heights are a first height and a second height, 4. The method for evaluating a multi-charged particle beam according to claim 1, wherein the position difference is a difference between a beam position measured at the first height and a beam position measured at the second height.

8. A program for evaluating a multi-charged particle beam, which evaluates trajectories of a plurality of individual beams in a multi-charged particle beam that has passed through a plurality of openings provided in an aperture array substrate, comprising: a step of setting a height in the optical axis direction of an image forming plane of the multi-charged particle beam or a measurement plane on which a mark for beam position measurement is formed to a plurality of different heights, and measuring the positions of the plurality of individual beams; extracting a specific beam having a change in beam trajectory from among the plurality of individual beams based on a position difference that is a difference between beam positions of the plurality of individual beams measured at the plurality of heights; A program that causes a computer to execute the following.

9. A multi-charged particle beam lithography method for lithography a pattern on a substrate using beams other than the singular beam extracted by the evaluation method of any one of claims 1 to 3, out of the multi-charged particle beams that have passed through a plurality of openings provided in the aperture array substrate.

10. A multi-charged particle beam drawing method as described in claim 9, in which a pattern is drawn on a substrate using a beam other than a beam within a region of a predetermined size centered on the singular beam.

11. 4. A method for inspecting an aperture array substrate for a multi-charged particle beam irradiation device, comprising: inspecting the aperture array substrate using position information of the specific beam extracted by the evaluation method of claim 1.

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