Multi-electron beam inspection device, multipole array control method, and multi-electron beam inspection method

Abstract

To provide a device capable of reducing the number of power sources used for a multipole array.SOLUTION: A multi electron beam inspection device comprises: an aberration corrector 220 including a plurality of multipoles disposed so as to enclose a corresponding beam of multi primary electron beams; a sub deflector 209 for scanning a surface of a substrate by performing collective beam deflection on the multi primary electron beams; a plurality of first sample / hold circuits 2 for holding a potential to be applied for each electrode of the plurality of multipoles; a plurality of power sources 5 for applying the potential to the first sample / hold circuits 2; an aberration correction circuit 121 for controlling the potential applied to the plurality of first sample / hold circuits 2 so as to hold the potential by a plurality of second sample / hold circuits selected from among the plurality of first sample / hold circuits 2 synchronously with swing-back of the collective beam deflection by an objective deflector; and a multi detector 222 for detecting multi secondary electron beams emitted by irradiating the substrate with the multi primary electron beams.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-electron beam inspection apparatus, a control method for a multipole array, and a multi-electron beam inspection method, for example, to a multipole array that corrects aberrations of multiple electron beams, and an apparatus that irradiates multiple electron beams and is equipped with a multipole array. [Background technology]

[0002] In recent years, with the increasing integration and capacity of large scale integrated circuits (LSIs), the circuit line width required for semiconductor elements has become narrower and narrower. In addition, improving the yield is essential for the manufacture of LSIs, which require a large manufacturing cost. However, as typified by 1 gigabit class DRAMs (random access memories), the patterns constituting LSIs are on the order of submicrons to nanometers. In recent years, with the miniaturization of LSI pattern dimensions formed on semiconductor wafers, the dimensions that must be detected as pattern defects have also become extremely small. Therefore, there is a need for high-precision pattern inspection devices that inspect defects in ultra-fine patterns transferred onto semiconductor wafers. Another major factor that reduces the yield is pattern defects in masks used when exposing and transferring ultra-fine patterns onto semiconductor wafers using photolithography technology. Therefore, there is a need for high-precision pattern inspection devices that inspect defects in transfer masks used in LSI manufacturing.

[0003] In the inspection device, for example, a multi-beam using an electron beam is irradiated onto the substrate to be inspected, secondary electrons corresponding to each beam emitted from the substrate to be inspected are detected, and a pattern image is captured. Then, a method of inspection is known in which the captured measurement image is compared with design data or a measurement image of the same pattern on the substrate. For example, there is a "die to die inspection" that compares measurement image data captured of the same pattern at different locations on the same substrate, and a "die to database inspection" that generates design image data (reference image) based on design data for a pattern design, and compares it with a measurement image that becomes measurement data captured by capturing the pattern. The captured image is sent to a comparison circuit as measurement data. In the comparison circuit, after aligning the images, the measurement data is compared with the reference data according to an appropriate algorithm, and if they do not match, it is determined that there is a pattern defect.

[0004] In an electron optical system using multiple beams, aberrations such as field curvature, off-axis astigmatism, or distortion (distortion aberration) may occur. In an inspection device using an electron beam, it is necessary to obtain high-precision images in order to perform inspections. To correct such aberrations, it is necessary to individually correct the trajectory of each beam of the multiple beams. For example, it is possible to arrange independent multipole lenses for each beam in an array (for example, see Patent Document 1).

[0005] Here, in order to correct each beam individually using the multipole lens, it is necessary to control each beam and each electrode individually. Therefore, a power supply is required for the number of beams multiplied by the number of multipole electrodes. As the number of beams increases, the number of power supplies also increases, which creates the problem of difficulty in implementation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-200983 A Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, one aspect of the present invention provides an apparatus and method that can reduce the number of power supplies used for a multipole array. [Means for solving the problem]

[0008] A multi-electron beam inspection apparatus according to one aspect of the present invention comprises: A stage on which a substrate is placed; an emission source that emits multiple primary electron beams; a multipole array having a plurality of multipoles each arranged to surround a corresponding beam among the multiple primary electron beams at a position through which the corresponding beam passes; an objective deflector that collectively deflects the multiple primary electron beams that have passed through the multipole array to scan the substrate with the multiple primary electron beams; a plurality of first sample-and-hold circuits each having a capacitor and a switch arranged for each of the electrodes of the plurality of multipoles, the first sample-and-hold circuits holding potentials to be applied to the electrodes by using the capacitors and the switches; a plurality of power sources that apply a plurality of potentials to the plurality of first sample and hold circuits; a control circuit that controls the first sample and hold circuits so that the potentials applied to the first sample and hold circuits are held by the second sample and hold circuits selected from the first sample and hold circuits in synchronization with a return of the collective beam deflection by the objective deflector; a detector for detecting multiple secondary electron beams emitted as a result of the multiple primary electron beams being irradiated onto the substrate; The present invention is characterized by comprising:

[0009] Moreover, the number of the multiple power sources is less than the value obtained by multiplying the number of beams of the multiple primary electron beams by the number of electrodes of the multipole element per beam.

[0010] Also, it is preferable that the number of the multiple power sources is smaller than the number of the multiple primary electron beams.

[0011] The control circuit further controls the plurality of power sources; The objective deflector scans a desired area for each beam by performing multiple line scan operations by repeating collective beam deflection, It is preferable that the control circuit switches the potentials of the plurality of power sources in synchronization with at least one of the plurality of line scanning operations.

[0012] A method for controlling a multipole array according to one aspect of the present invention includes the steps of: applying a plurality of potentials to a plurality of first sample and hold circuits using capacitors and switches to hold potentials for application to the electrodes; holding the multiple potentials applied to the multiple first sample and hold circuits in multiple second sample and hold circuits selected from the multiple first sample and hold circuits in synchronization with return of the collective beam deflection of the multiple primary electron beams by an objective deflector that scans a substrate with the multiple primary electron beams by collective beam deflection of the multiple primary electron beams; applying the potentials held in the second sample-and-hold circuits to electrodes connected to the second sample-and-hold circuits in the multipoles arranged to surround corresponding beams at positions through which the corresponding beams pass among the multiple primary electron beams; The present invention is characterized by comprising:

[0013] A multi-electron beam inspection method according to one aspect of the present invention includes: emitting multiple primary electron beams; a step of scanning a substrate placed on a stage with the multiple primary electron beams using an objective deflector that performs collective beam deflection of the multiple primary electron beams; applying a plurality of potentials to a plurality of first sample and hold circuits using capacitors and switches to hold potentials for application to the electrodes; holding the potentials applied to the first sample and hold circuits in second sample and hold circuits selected from the first sample and hold circuits in synchronization with return of collective beam deflection of the multiple primary electron beams by the objective deflector; applying the potentials held in the second sample-and-hold circuits to electrodes connected to the second sample-and-hold circuits in the multipoles arranged to surround corresponding beams at positions through which the corresponding beams pass among the multiple primary electron beams; individually correcting aberrations of the multiple primary electron beams by a multipole array having a plurality of multipoles; detecting multiple secondary electron beams emitted as a result of the multiple primary electron beams being irradiated onto the substrate; A step of comparing a detection image based on the detected detection signal with a reference image and outputting the result; The present invention is characterized by comprising: Effect of the Invention

[0014] According to one aspect of the present invention, the number of power supplies used in a multipole array can be reduced. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a configuration diagram showing a configuration of a pattern inspection device according to a first embodiment. [Diagram 2] 2 is a conceptual diagram showing a configuration of a shaping aperture array substrate in the first embodiment. FIG. [Diagram 3] 1 is a diagram showing an example of a plurality of chip regions formed on a semiconductor substrate in the first embodiment. [Figure 4] FIG. 2 is a diagram for explaining a multi-beam scanning operation in the first embodiment. [Diagram 5] 3 is a top view showing an example of the configuration of each electrode substrate of the aberration corrector in the first embodiment. FIG. [Figure 6] 2 is a cross-sectional view showing an example of the configuration of an aberration corrector in the first embodiment. [Figure 7] FIG. 2 is a diagram for explaining a multipole element and an applied potential in the first embodiment. [Figure 8] FIG. 2 is a diagram illustrating an example of a plurality of sample-and-hold circuits according to the first embodiment. [Figure 9] 5 is a diagram for explaining a method of controlling line scanning and a sample-and-hold circuit in the first embodiment. FIG. [Figure 10] FIG. 4 is a diagram showing an example of a time chart of a control pulse signal in the first embodiment. [Figure 11] FIG. 2 is a diagram illustrating an example of a configuration of a power supply according to the first embodiment. [Figure 12] FIG. 4 is a diagram for explaining the number of wirings in the first embodiment. [Figure 13] FIG. 3 is a diagram showing an example of distortion in the first embodiment. [Figure 14] FIG. 3 is a diagram showing an example of an astigmatism in the first embodiment. [Figure 15] FIG. 11 is a diagram showing another example of an astigmatism in the first embodiment. [Figure 16] 4 is a configuration diagram showing an example of the internal configuration of a comparison circuit according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In the following, in the embodiment, a multi-electron beam inspection device will be described as an example of a multi-electron beam irradiation device. However, the multi-electron beam irradiation device is not limited to an inspection device, and may be a drawing device or the like that irradiates multiple electron beams using an electron optical system.

[0017] Embodiment 1 FIG. 1 is a configuration diagram showing the configuration of a pattern inspection apparatus in the first embodiment. In FIG. 1, an inspection apparatus 100 for inspecting a pattern formed on a substrate is an example of a multi-electron beam inspection apparatus. The inspection apparatus 100 includes an image acquisition mechanism 150 and a control circuit 160. The image acquisition mechanism 150 includes an electron beam column 102 (electron lens barrel) and an inspection chamber 103. In the electron beam column 102, an electron gun 201, an electromagnetic lens 202, a shaping aperture array substrate 203, an electromagnetic lens 205, an aberration corrector 220, an electrostatic lens 221, a collective blanking deflector 212, a limiting aperture substrate 213, an electromagnetic lens 206, an electromagnetic lens 207 (objective lens), a main deflector 208, a sub-deflector 209, an E×B separator 214, a deflector 218, an electromagnetic lens 224, and a multi-detector 222 are arranged. A primary electron optical system is constituted by the electron gun 201, the electromagnetic lens 202, the shaping aperture array substrate 203, the electromagnetic lens 205, the aberration corrector 220, the electrostatic lens 221, the collective blanking deflector 212, the limiting aperture substrate 213, the electromagnetic lens 206, the electromagnetic lens 207 (objective lens), the main deflector 208, and the sub-deflector 209. A secondary electron optical system is constituted by the electromagnetic lens 207, the E×B separator 214, the deflector 218, and the electromagnetic lens 224. The electron beam column 102 and the inspection chamber 103 are evacuated to a desired vacuum state by a vacuum pump (not shown).

[0018] In the inspection chamber 103, a stage 105 movable at least in the XY direction is arranged. On the stage 105, a substrate 101 (sample) to be inspected is arranged. The substrate 101 includes an exposure mask substrate and a semiconductor substrate such as a silicon wafer. When the substrate 101 is a semiconductor substrate, a plurality of chip patterns (wafer dies) are formed on the semiconductor substrate. When the substrate 101 is an exposure mask substrate, a chip pattern is formed on the exposure mask substrate. The chip pattern is composed of a plurality of figure patterns. The chip pattern formed on the exposure mask substrate is exposed and transferred onto the semiconductor substrate a plurality of times, so that a plurality of chip patterns (wafer dies) are formed on the semiconductor substrate. The following mainly describes the case where the substrate 101 is a semiconductor substrate. The substrate 101 is arranged on the stage 105 with, for example, a pattern forming surface facing upward. In addition, on the stage 105, a mirror 216 is arranged to reflect a laser beam for laser measurement irradiated from a laser measurement system 122 arranged outside the inspection chamber 103. The multi-detector 222 is connected to a detection circuit 106 outside the electron beam column 102. The detection circuit 106 is connected to a chip pattern memory 123.

[0019] In the control system circuit 160, a control computer 110 that controls the entire inspection apparatus 100 is connected to a position circuit 107, a comparison circuit 108, a reference image creation circuit 112, a stage control circuit 114, an aberration correction circuit 121, a lens control circuit 124, a blanking control circuit 126, a deflection control circuit 128, a power supply circuit 132, a storage device 109 such as a magnetic disk device, a monitor 117, a memory 118, and a printer 119 via a bus 120. The deflection control circuit 128 is also connected to DAC (digital-to-analog conversion) amplifiers 144, 146, and 148. The DAC amplifier 146 is connected to a main deflector 208, and the DAC amplifier 144 is connected to a sub-deflector 209. The DAC amplifier 148 is connected to a deflector 218.

[0020] The chip pattern memory 123 is connected to the comparison circuit 108. The stage 105 is driven by a driving mechanism 142 under the control of the stage control circuit 114. The driving mechanism 142 is configured with a driving system such as a three-axis (XY-θ) motor that drives in the X, Y, and θ directions in the stage coordinate system, and the stage 105 can be moved in the X, Y, and θ directions. These X, Y, and θ motors (not shown) can be, for example, step motors. The stage 105 can be moved in the horizontal and rotational directions by the motors of the X, Y, and θ axes. The moving position of the stage 105 is measured by a laser length measurement system 122 and supplied to a position circuit 107. The laser length measurement system 122 measures the position of the stage 105 by receiving the reflected light from the mirror 216 based on the principle of laser interference. For example, the X, Y, and θ directions of the stage coordinate system are set with respect to a plane perpendicular to the optical axis of the multi-primary electron beams 20.

[0021] The electromagnetic lens 202, the electromagnetic lens 205, the electromagnetic lens 206, the electromagnetic lens 207 (objective lens), the electromagnetic lens 224, and the E×B separator 214 are controlled by a lens control circuit 124. The collective blanking deflector 212 is composed of two or more electrodes, and is controlled by the blanking control circuit 126 via a DAC amplifier (not shown) for each electrode.

[0022] Furthermore, in the control system circuit 160, a sample and hold circuit board 130 is further arranged. The sample and hold circuit board 130 is preferably arranged inside the electron beam column 102. Therefore, the sample and hold circuit board 130 is arranged in a vacuum atmosphere. On the other hand, the aberration correction circuit 121 and the power supply circuit 132 are arranged inside the control room. Therefore, the sample and hold circuit board 130 is connected to the aberration correction circuit 121 and the power supply circuit 132 on the atmospheric pressure side via a feedthrough (not shown). The sample and hold circuit board 130 is connected to an aberration corrector 220 (an example of a multipole array).

[0023] In the sample-and-hold circuit board 130, a plurality of sample-and-hold circuits are arranged, as described later. In the power supply circuit 132, a plurality of power supplies are arranged, as described later. The aberration correction circuit 121 (control circuit) controls the plurality of sample-and-hold circuits. The aberration correction circuit 121 further controls the plurality of power supplies.

[0024] The aberration corrector 220 is composed of two or more stages of electrode substrates as described below, and is controlled by the aberration correction circuit 121 via the sample-and-hold circuit board 130. The electrostatic lens 221 is composed of, for example, three or more stages of electrode substrates, with an opening formed in the center through which the entire multi-primary electron beams can pass, and is controlled by the aberration correction circuit 121.

[0025] The sub-deflector 209 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 128 via the DAC amplifier 144. The main deflector 208 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 128 via the DAC amplifier 146. The deflector 218 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 128 via the DAC amplifier 148.

[0026] A high-voltage power supply circuit (not shown) is connected to the electron gun 201, and an acceleration voltage from the high-voltage power supply circuit is applied between a filament (cathode) (not shown) and an extraction electrode (anode) inside the electron gun 201. In addition, a voltage is applied to another extraction electrode (Wehnelt) and the cathode is heated to a predetermined temperature, whereby a group of electrons emitted from the cathode are accelerated and emitted as an electron beam 200.

[0027] 1 shows the configuration necessary for explaining the embodiment 1. The inspection device 100 may also include other configurations that are normally required.

[0028] 2 is a conceptual diagram showing the configuration of the shaping aperture array substrate in the embodiment 1. In FIG. 2, the shaping aperture array substrate 203 has a two-dimensional lateral (x direction) m 1 Column x vertical (y direction) n1 Step (m 1 ,n 1 The holes (openings) 22 are formed at a predetermined arrangement pitch in the x and y directions (where x is an integer of 2 or more). In the example of FIG. 2, for example, 11×11 holes (openings) 22 are formed. Each hole 22 is formed as a rectangle of the same size and shape. Alternatively, they may be circles of the same outer diameter. A part of the electron beam 200 passes through each of these holes 22, thereby forming the multi-primary electron beams 20. The shaping aperture array substrate 203 is an example of an emission source that emits the multi-primary electron beams 20. Here, an example in which the holes 22 are arranged in two or more rows in both the horizontal and vertical directions (x and y directions) is shown, but this is not limited to this. For example, one of the horizontal and vertical directions (x and y directions) may be multiple rows and the other may be only one row. In addition, the arrangement of the holes 22 is not limited to the case in which the holes 22 are arranged in a lattice pattern in the horizontal and vertical directions as shown in FIG. 2. For example, the holes in the kth column and the k+1th column in the vertical direction (y direction) may be shifted by a dimension a in the horizontal direction (x direction). Similarly, the holes in the k+1th column and the k+2th column in the vertical direction (y direction) may be shifted by a dimension b in the horizontal direction (x direction).

[0029] Next, the operation of the image acquisition mechanism 150 in the inspection device 100 will be described.

[0030] An electron beam 200 emitted from an electron gun 201 (emission source) is refracted by an electromagnetic lens 202, and illuminates the entire shaping aperture array substrate 203. A plurality of holes 22 (openings) are formed in the shaping aperture array substrate 203 as shown in Fig. 2, and the electron beam 200 illuminates an area including all of the plurality of holes 22. Each portion of the electron beam 200 irradiated to the positions of the plurality of holes 22 passes through each of the plurality of holes 22 in the shaping aperture array substrate 203, thereby forming multiple primary electron beams 20 (multiple primary electron beams).

[0031] The formed multi-primary electron beams 20 are refracted by the electromagnetic lenses 205 and 206, respectively, and while repeating intermediate images and crossovers, pass through the E×B separator 214 arranged at the intermediate image position of each beam of the multi-primary electron beams 20 and proceed to the electromagnetic lens 207 (objective lens). During this time, aberrations such as field curvature, astigmatism, and / or distortion are corrected by the aberration corrector 220. In addition, when the correction by the aberration corrector 220 causes a shift in the focal position of the beam, the electrostatic lens 221 corrects the shift in the focal position collectively. In the example of FIG. 1, the aberration corrector 220 is arranged in the magnetic field of the electromagnetic lens 205. By arranging the aberration corrector 220 in the magnetic field of the electromagnetic lens 205, the potential applied to the control electrode of the aberration corrector 220 can be made smaller than that when it is arranged outside the magnetic field. For example, it can be made smaller to about 1 / 100. However, this is not limited to this. The aberration corrector 220 may be disposed between the shaping aperture array substrate 203 and the E×B separator 214 .

[0032] When the multi-primary electron beams 20 are incident on the electromagnetic lens 207 (objective lens), the electromagnetic lens 207 focuses the multi-primary electron beams 20 on the substrate 101. In other words, the electromagnetic lens 207 (an example of an electron optical system) guides the multi-primary electron beams 20 to the substrate 101 after at least one of the field curvature, astigmatism, and distortion aberration is corrected by the aberration corrector 220. The multi-primary electron beams 20 focused on the substrate 101 (sample) surface by the objective lens 207 are deflected collectively by the main deflector 208 and the sub-deflector 209, and are irradiated on the respective irradiation positions on the substrate 101 of each beam. When the entire multi-primary electron beams 20 are deflected collectively by the collective blanking deflector 212, the position is shifted from the hole in the center of the limiting aperture substrate 213, and the entire multi-primary electron beams 20 are shielded by the limiting aperture substrate 206. On the other hand, the multi primary electron beams 20 that are not deflected by the collective blanking deflector 212 pass through a hole in the center of the limiting aperture substrate 206 as shown in Fig. 1. Blanking control is performed by turning on / off the collective blanking deflector 212, and the beams are collectively controlled to be turned on / off. In this way, the limiting aperture substrate 206 shields the multi primary electron beams 20 that are deflected by the collective blanking deflector 212 to be in the beam OFF state. Then, the multi primary electron beams 20 for inspection (for image acquisition) are formed by a group of beams that have passed through the limiting aperture substrate 206 from when the beams are turned on until when they are turned off.

[0033] When the multi primary electron beams 20 are irradiated onto a desired position on the substrate 101, a bundle of secondary electrons (multi secondary electron beams 300) including reflected electrons corresponding to each beam of the multi primary electron beams 20 (multi primary electron beams) is emitted from the substrate 101 as a result of the irradiation of the multi primary electron beams 20.

[0034] The multiple secondary electron beams 300 emitted from the substrate 101 pass through an electromagnetic lens 207 and proceed to an E×B separator 214 .

[0035] Here, the E×B separator 214 (beam separator) has two or more magnetic poles using coils and two or more electrodes. A directional magnetic field is generated by the multiple magnetic poles. Similarly, a directional electric field is generated by the multiple electrodes. Specifically, the E×B separator 214 generates an electric field and a magnetic field in a direction perpendicular to the direction (orbital central axis) of the central beam of the multiple primary electron beams 20. The electric field exerts a force in the same direction regardless of the direction of electron movement. In contrast, the magnetic field exerts a force according to Fleming's left-hand rule. Therefore, the direction of the force acting on the electrons can be changed depending on the direction of entry of the electrons. The force due to the electric field and the force due to the magnetic field cancel each other out for the multiple primary electron beams 20 entering the E×B separator 214 from above, and the multiple primary electron beams 20 proceed straight downward. In contrast, the multiple secondary electron beams 300 entering the E×B separator 214 from below are subjected to forces due to the electric field and the magnetic field in the same direction, so that the multiple secondary electron beams 300 are bent obliquely upward and separated from the multiple primary electron beams 20.

[0036] The multi secondary electron beams 300 bent obliquely upward and separated from the multi primary electron beams 20 are further bent by the deflector 218 and projected onto the multi detector 222 while being refracted by the electromagnetic lens 224. The multi detector 222 detects the projected multi secondary electron beams 300. The multi detector 222 has, for example, a diode-type two-dimensional sensor (not shown). Then, at the diode-type two-dimensional sensor positions corresponding to the respective beams of the multi primary electron beams 20, the secondary electrons of the multi secondary electron beams 300 collide with the diode-type two-dimensional sensor to generate electrons, and secondary electron image data is generated for each pixel. The intensity signal detected by the multi detector 222 is output to the detection circuit 106.

[0037] 3 is a diagram showing an example of a plurality of chip regions formed on a semiconductor substrate in the first embodiment. In FIG. 3, when substrate 101 is a semiconductor substrate (wafer), a plurality of chips (wafer dies) 332 are formed in a two-dimensional array in inspection region 330 of the semiconductor substrate (wafer). A mask pattern for one chip formed on an exposure mask substrate is transferred onto each chip 332 by an exposure device (stepper) (not shown), reduced to, for example, 1 / 4. Within each chip 332, for example, a two-dimensional horizontal (x direction) m 2 Column x vertical (y direction) n 2 Step (m 2 ,n 2 The mask die 33 is divided into a plurality of mask dies 33 (wherein the mask die 33 is an integer equal to or greater than 2). In the first embodiment, each mask die 33 is a unit inspection area. The beam is moved to a target mask die 33 by collective deflection of the entire multi primary electron beams 20 by the main deflector 208.

[0038] FIG. 4 is a diagram for explaining the scanning operation of the multi-beam in the first embodiment. The example of FIG. 4 shows the case of the multi-primary electron beam 20 of 5×5 rows. The irradiation area 34 that can be irradiated by one irradiation of the multi-primary electron beam 20 is defined as (x-direction size obtained by multiplying the inter-beam pitch in the x direction of the multi-primary electron beam 20 on the substrate 101 surface by the number of beams in the x direction)×(y-direction size obtained by multiplying the inter-beam pitch in the y direction of the multi-primary electron beam 20 on the substrate 101 surface by the number of beams in the y direction). The example of FIG. 4 shows the case where the irradiation area 34 is the same size as the mask die 33. However, this is not limited thereto. The irradiation area 34 may be smaller than the mask die 33. Or it may be larger than the mask die 33. Then, each primary electron beam 9 of the multi-primary electron beam 20 scans (scans) within the sub-irradiation area 29 surrounded by the inter-beam pitch in the x direction and the inter-beam pitch in the y direction where the beam is located. Each beam constituting the multi primary electron beam 20 is assigned to one of the sub-irradiation regions 29, which are different from each other. During each shot, each beam irradiates the same position in the assigned sub-irradiation region 29. The movement of the beam in the sub-irradiation region 29 is performed by collective deflection of the entire multi primary electron beam 20 by the sub-deflector 209. By repeating this operation, one beam is used to sequentially irradiate the entire one sub-irradiation region 29. In the example of FIG. 4, the sub-irradiation region 29 is scanned with four lines proceeding in the y direction, but in reality, more lines are scanned as described later. For example, 512 lines are scanned.

[0039] When a desired position on the substrate 101 is irradiated with the multi primary electron beams 20, the aberration of which has been corrected by the aberration corrector 220, a multi secondary electron beam 300 including reflected electrons corresponding to the multi primary electron beams 20 is emitted from the substrate 101. The multi secondary electron beams 300 emitted from the substrate 101 proceed to the E×B separator 214 and are bent obliquely upward. The trajectory of the multi secondary electron beams 300 bent obliquely upward is bent by the deflector 218, and the multi secondary electron beams 300 are projected onto the multi detector 222. In this manner, the multi detector 222 detects the multi secondary electron beams 300 emitted when the multi primary electron beams 20 are irradiated onto the substrate 101 surface. The reflected electrons may diverge midway along the optical path.

[0040] As described above, the mask die 33 is scanned as an irradiation region 34 by the entire multi-primary electron beams 20, with each beam scanning one corresponding sub-irradiation region 29. Then, when scanning of one mask die 33 is completed, the next adjacent mask die 33 is moved so that it becomes the irradiation region 34, and scanning of the next adjacent mask die 33 is performed. This operation is repeated to scan each chip 332. Each time a shot of the multi-primary electron beams 20 is made, secondary electrons are emitted from the irradiated position and detected by the multi-detector 222.

[0041] FIG. 5 is a top view showing an example of the configuration of each electrode substrate of the aberration corrector in the first embodiment. FIG. 6 is a cross-sectional view showing an example of the configuration of the aberration corrector according to the first embodiment. The aberration corrector 220 is composed of two or more stages of electrode substrates arranged with a predetermined gap therebetween. The examples of Fig. 5(a) and Fig. 5(b) show a case where 5 x 5 multi primary electron beams 20 are used. The aberration corrector 220 (multipole array) has a plurality of multipoles 13 arranged so as to surround a corresponding beam among the multi primary electron beams 20 at a position where the corresponding beam passes through. A specific description will be given below.

[0042] In the first electrode substrate 10, a plurality of passage holes 11 (first passage holes) through which the multi-primary electron beams 20 pass are formed in the substrate body 12. As shown in FIG. 5(a) and FIG. 6, in the first electrode substrate 10, a plurality of passage holes 11 are formed at positions through which the multi-primary electron beams 20 pass at the beam pitch P. The plurality of passage holes 11 in the first electrode substrate 10 are formed so that they have a hole diameter D2 (second hole diameter) from the top surface (upstream side in the beam traveling direction) of the substrate body 12 to the middle of the back surface, and have a hole diameter D3 (third hole diameter) from the middle of the way to the back surface. In addition, as shown in FIG. 6, the top surface, side surface, and bottom surface of the substrate body 12 and the inner walls of the plurality of passage holes 11 are covered with a shield electrode 44. The shield electrode 44 is disposed on at least the inner walls of the plurality of passage holes 11.

[0043] The second electrode substrate 14 is disposed on the lower side (downstream side in the beam traveling direction) of the first electrode substrate 10. In the second electrode substrate 14, a plurality of passage holes 17 (second passage holes) are formed in the substrate body 15, through which the multi-primary electron beams 20 with the beam pitch P pass. As shown in FIG. 5(b) and FIG. 6, the plurality of passage holes 17 of the second electrode substrate 14 are formed from the upper surface to the rear surface of the substrate body 15 with a hole diameter D1 (first hole diameter). A multipole element 13 with four or more poles is disposed on the upper surface around the passage hole 17 for each passage hole 17. A plurality of electrodes 16 (an example of a first electrode) are disposed as the multipole element 13. FIG. 5(b) shows a case where eight electrodes 16 (a to h) (an example of a first electrode) are disposed. For example, in the case of correcting the distortion aberration of the multi-primary electron beams 20, four-pole electrodes 16 may be disposed in pairs facing each other in orthogonal directions (x and y directions) for each beam. For example, in the case of correcting astigmatism of multiple primary electron beams 20, it is preferable to arrange eight electrodes 16 for each beam, in which two poles are arranged opposite each other in the orthogonal directions (x, y directions) as well as in the 45° and 135° directions that are intermediate phases. If the direction of astigmatism is known, four electrodes 16 may be arranged opposite each other in the orthogonal directions (x, y directions). In addition, in the second electrode substrate 14, an insulating layer 40 is arranged between the substrate body 15 and the multiple electrodes 16 (a to h) for each beam. In addition, as shown in FIG. 6, the side and bottom surfaces of the substrate body 15 and the inner walls of the multiple through holes 17 are covered with a shield electrode 42.

[0044] The material of the substrate body 12 of the first electrode substrate 10 and the material of the substrate body 15 of the second electrode substrate 14 are both preferably silicon (Si). The substrate bodies 12, 15 are preferably Si substrates having a thickness of, for example, about several hundreds of μm. The material of each of the electrodes 16 (a-h) for each beam is preferably a metal that is not easily oxidized, such as aluminum (Al), platinum (Pt), titanium (Ti), or palladium (Pd). The material of the shield electrodes 42, 44 is preferably a metal that is not easily oxidized, such as Al, Pt, Ti, or Pd, similar to the electrode 16.

[0045] When correcting astigmatism and distortion, a potential of +V is applied to one of the two opposing electrodes among the multiple electrodes 16 for one beam. A potential of the same potential but with the opposite sign, -V, is applied to the other electrode. When correcting field curvature, the same potential is applied to the multiple electrodes 16 for one beam. In addition, a ground (GND) potential is applied to the shield electrodes 42, 44.

[0046] Here, in the aberration corrector 220, as shown in FIG. 6, the passage hole 11 of the first electrode substrate 10 is formed wider than the passage hole 17 in which the electrode 16 of the second electrode substrate 14 is disposed. Therefore, the upper part of the electrode 16 is open due to the passage hole 11. Therefore, the electric field E can be spread to the space in the passage hole 11 on the two opposing electrodes 16. In addition, since the upper part of the passage hole 11 of the first electrode substrate 10 shown in FIG. 6 is narrowed from the hole diameter D3 to the hole diameter D2 by the brim part, the direction of the electric field line can be easily bent. Therefore, the electric field E can be formed in the passage hole 11 on the two opposing electrodes 16 without diverging upward from the upper electrode substrate 10. Therefore, an electric field can be applied to the electron beam that has entered the passage hole 11 of the first electrode substrate 10 while passing through the passage hole 11. Therefore, the deflection fulcrum can be provided midway through the passage hole 11 on the electrode 16. The thickness of the electrode 16 itself can be reduced accordingly.

[0047] FIG. 7 is a diagram for explaining the multipole elements and applied potentials in the first embodiment. In FIG. 7, eight electrodes 16a to 16h are arranged as the multipole elements 13 for each beam so as to surround the corresponding beam at a position where the corresponding beam passes. In FIG. 7, an electrode (Eij) with electrode number j for a beam with index i among the multiple primary electron beams 20 arranged in an array is shown. j indicates electrode numbers 1 to 8. In FIG. 7, electrodes Ei1 to Ei8 for a beam with index i are shown. A potential V1 is applied to the electrode 16a (E11). A potential V2 is applied to the electrode 16b. A potential V3 is applied to the electrode 16c. A potential V4 is applied to the electrode 16d. A potential V5 is applied to the electrode 16e. A potential V6 is applied to the electrode 16f. A potential V7 is applied to the electrode 16g. A potential V8 is applied to the electrode 16h.

[0048] In order to correct each beam individually using a multipole array such as the aberration corrector 220, it is necessary to control each beam and each electrode individually. Therefore, a power supply is required for the number of beams x the number of electrodes of the multipole. As the number of beams increases, the number of power supplies also increases, which is a problem in that it becomes difficult to implement. For example, in the case of 11 x 11 multi-primary electron beams, there are beams i = 1 to 121. In the aberration corrector 220, when eight electrodes 16 are arranged for each beam, 121 x 8 power supplies are required to correct each beam individually. Therefore, in the first embodiment, a sample hold circuit is arranged for each of the electrodes of 8 electrodes x the number of beams. Such a plurality of sample hold circuits (first sample hold circuits) have a capacitor and a switch arranged for each electrode 16 of the plurality of multipole elements 13, and hold a potential to be applied to the electrode 16 using the capacitor and the switch. A specific description will be given below.

[0049] FIG. 8 is a diagram showing an example of a plurality of sample and hold circuits in the first embodiment. In FIG. 8, eight sample and hold circuits 2 for connection to a plurality of electrodes Ei1 to Ei8 for the same beam are arranged in the horizontal direction. The same eight sample and hold circuits 2 are arranged in the vertical direction, the number of which corresponds to the number of beams. The example in FIG. 8 shows a case in which 11×11 multi-primary electron beams 20 are used. In that case, since there are 121 beams, 121 sample and hold circuits 2 are arranged in the vertical direction. Therefore, a total of 121×8 sample and hold circuits (first sample and hold circuits) are arranged.

[0050] Each sample-and-hold circuit 2 has a switch 3 and a capacitor 4. The inputs of the eight switches 3 for beam i are connected to the line of the control pulse signal SLi. For example, the inputs of the eight switches 3 for beam 1 are connected to the line of the control pulse signal SL1. The inputs of the eight switches 3 for beam 121 are connected to the line of the control pulse signal SL121. The switch 3 with electrode number 1 for each beam is connected to the line of potential V1 from the power supply 1. Similarly, the switch 3 with electrode number 2 for each beam is connected to the line of potential V2 from the power supply 2. Similarly, the switch 3 with electrode number 8 for each beam is connected to the line of potential V8 from the power supply 8. One terminal of the capacitor 4 and the corresponding electrode Eij are connected in parallel to the output of each switch 3. The other terminal of each capacitor is connected to the ground potential. In this way, 121×8 sample-and-hold circuits 2 are arranged in an array. Such 121×8 sample-and-hold circuits 2 are arranged in a sample-and-hold circuit board 130.

[0051] In addition, in the power supply circuit 132, a plurality of power supplies are arranged to apply a plurality of potentials to a plurality of sample-and-hold circuits in the sample-and-hold circuit board 130. The number of the plurality of power supplies is less than the value obtained by multiplying the number of beams of the multi-primary electron beams 20 by the number of electrodes of the multipole element 13 per beam. Furthermore, the number of the plurality of power supplies is less than the number of beams of the multi-primary electron beams 20. For example, the same number of power supplies as the number of electrodes per beam are arranged. Here, eight power supplies 1 to 8 are arranged. A potential V1 from the power supply 1 is connected to the switch 3 of electrode number 1 for each beam. A potential V2 from the power supply 2 is connected to the switch 3 of electrode number 2 for each beam. Thereafter, a potential V8 from the power supply 8 is connected to the switch 3 of electrode number 8 for each beam in a similar manner.

[0052] FIG. 9 is a diagram for explaining a method of controlling the line scan and the sample-and-hold circuit in the first embodiment. The sub-deflector 209, which is an example of an objective deflector, collectively deflects the multi-primary electron beams 20 that have passed through the aberration corrector 220 (multipole array), thereby scanning the substrate 101 with the multi-primary electron beams 20. The sub-deflector 209 scans the sub-irradiation region 29 (within a desired region) for each beam by performing a plurality of line scanning operations by repeating the collective beam deflection. Specifically, for example, in FIG. 9, in each sub-irradiation region 29, 512 line scans are performed with the corresponding primary electron beam 9. When one line scan is completed, the beam is deflected back to the start position of the next line scan. To scan the entirety of one sub-irradiation region 29, such an operation is repeated, for example, 512 times.

[0053] The aberration correction circuit 121 (control circuit) controls the 121×8 sample hold circuits 2 (first sample hold circuits) so that the multiple potentials V1 to V8 applied to the 121×8 sample hold circuits 2 (first sample hold circuits) are held by eight multiple sample hold circuits 2 (second sample hold circuits) selected from the 121×8 sample hold circuits in synchronization with the return of the collective beam deflection by the sub-deflector 209, which is an objective deflector. Also, the aberration correction circuit 121 switches the potentials V1 to V8 of the multiple power supplies 1 to 8 in synchronization with at least one line scan operation of the multiple line scan operations.

[0054] FIG. 10 is a diagram showing an example of a time chart of the control pulse signal in the first embodiment. For example, during the first line scan operation, the potentials V1 to V8 of the power supplies 1 to 8 are switched to the potentials V1 to V8 for beam 1 correction. Then, after the first line scan is completed, the control pulse signal SL1 is transmitted, for example, once in synchronization with the timing of returning the beam to the starting position of the second line scan. As a result, while the control pulse signal SL1 is in the ON state, the potentials V1 to V8 are applied to the electrodes E11 to E18 constituting the multipole element 13 for beam 1 correction. At the same time, the potentials V1 to V8 are applied to the capacitors 4 of the eight sample-hold circuits 2 for beam 1 correction. Even when the control pulse signal SL1 is turned OFF, the eight sample-hold circuits 2 for beam 1 correction hold the respective potentials V1 to V8. Specifically, the respective potentials V1 to V8 stored in the capacitors 4 of the eight sample-hold circuits 2 for beam 1 correction are applied to the electrodes E11 to E18. Therefore, the potentials V1 to V8 for correcting beam 1 are continuously applied to the electrodes E11 to E18 constituting the multipole element 13 for correcting beam 1. As a result, the aberration of beam 1 is corrected.

[0055] After the first deflection is completed, during the second line scan operation, the potentials V1 to V8 of the power supplies 1 to 8 are switched to the potentials V1 to V8 for beam 2 correction. Then, after the second line scan is completed, the control pulse signal SL2 is transmitted, for example, once in synchronization with the timing of deflecting the beam back to the starting position of the third line scan. As a result, while the control pulse signal SL1 is in the ON state, the potentials V1 to V8 are applied to the electrodes E11 to E18 constituting the multipole element 13 for beam 2 correction. At the same time, the potentials V1 to V8 are applied to the capacitors 4 of the eight sample-hold circuits 2 for beam 2 correction. Even when the control pulse signal SL2 is turned OFF, the eight sample-hold circuits 2 for beam 2 correction hold the respective potentials V1 to V8. Specifically, the respective potentials V1 to V8 stored in the capacitors 4 of the eight sample-hold circuits 2 for beam 1 correction are applied to the electrodes E21 to E28. Therefore, the potentials V1 to V8 for correcting beam 2 are continuously applied to the electrodes E21 to E28 constituting the multipole element 13 for correcting beam 2. As a result, the aberration of beam 2 is corrected.

[0056] By repeating this operation 121 times, all of the beam correction potentials V1 to V8 continue to be applied to the electrodes Ei1 to Ei8 that configure the respective beam correction multipole elements 13. This allows the aberration of each beam to be individually corrected.

[0057] FIG. 11 is a diagram showing an example of the configuration of a power supply in the first embodiment. FIG. 11 shows one of eight power supplies arranged in the power supply circuit 132. Each power supply 5 has a D / A (digital-analog) converter 7 and an operational amplifier 6. Each power supply 5 variably adjusts the potential using the D / A converter 7 and the operational amplifier 6. The required range of potential is controlled with a resolution of, for example, 16 bits (512 gradations). The aberration correction circuit 121 outputs a 16-bit digital control potential signal indicating the potential for the beam to be applied next to the D / A converter 7. The D / A converter 7 performs D / A conversion and outputs to the operational amplifier 6, and the desired potential is output to the sample-and-hold circuit as the output of the operational amplifier 6.

[0058] Here, if the potential for each electrode is sampled and held once for each of the 121 beams, the operation is completed with 121 line scans. If 512 lines are scanned, four sample holds can be performed for each of the 121 lines. In other words, the potential applied to each beam control electrode 16 can be refreshed four times. If the scanning of 512 lines takes, for example, 4.5 ms, 1.125 ms is required until the next refresh. If the allowable voltage fluctuation when the electrode 16 is irradiated with 1 nA electrons is 100 μV, the capacitance C of the capacitor 4 needs to be 1 nA × 1.125 ms / 100 μV = 11.25 nF or more. A capacitor with such a capacitance can be implemented.

[0059] In the above example, the scan cycle for one line is 8.789 μs. Of that, it takes 500 ns for the reset. It is sufficient if the refresh is completed within that time. Simulation results showed that the refresh was possible.

[0060] FIG. 12 is a diagram for explaining the number of wirings in the first embodiment. The aberration corrector 220 requires power supplies equal to the number of beams times the number of electrodes. Therefore, the sample-and-hold circuit board 130 and the aberration corrector 220 are connected by wirings equal to at least the number of beams times the number of electrodes (for example, 121 x 8). On the other hand, the number of wirings between the sample-and-hold circuit board 130 and the aberration corrector 220 can be reduced to 121, which is the number of control pulse signals SLi, and 8, which is the number of power sources. Therefore, the number of wirings between the relaying feedthrough and the sample-and-hold circuit board 130 can be reduced to 121, which is the number of control pulse signals SLi, and 8, which is the number of power sources. In this way, the number of wirings of the feedthrough arranged at the boundary between the atmospheric pressure environment and the vacuum environment can be reduced.

[0061] FIG. 13 is a diagram showing an example of distortion in the first embodiment. The example in FIG. 13 shows a case where 5×5 multi-primary electron beams 20 are used. If the holes 22 in the shaping aperture array substrate 203 are formed in a matrix at a predetermined pitch in the x and y directions, ideally, as shown in FIG. 13(b), the irradiation positions 19 of the multi-primary electron beams 20 irradiated on the substrate 101 should also be arranged in a matrix at a predetermined reduction ratio. However, by using an electron optical system such as an electromagnetic lens, distortion (distortion aberration) occurs as shown in FIG. 13(a). The shape of the distortion takes a distribution called a barrel type or a pincushion type depending on the conditions. In general, the distortion of a magnetic lens causes a deviation in the rotation direction in addition to the radial direction. FIG. 13(a) shows an example under the condition where no rotation component occurs. The direction and position deviation amount of the distortion generated in the multi-primary electron beams 20 differ for each beam, even if there is a certain tendency. Therefore, in order to correct such distortion, it is necessary to perform correction for each individual beam. By correcting the beam trajectory for each beam using the aberration corrector 220 in the first embodiment, it is possible to correct the irradiation position 19 of the multiple primary electron beams 20 irradiated onto the substrate 101 as shown in FIG. 13(b).

[0062] FIG. 14 is a diagram showing an example of astigmatism in the first embodiment. In the example of FIG. 14, a case where 5×5 multi-primary electron beams 20 are used is shown. As shown in FIG. 14(b), ideally, each beam is irradiated in a circular shape. However, by using an electron optical system such as an electromagnetic lens, astigmatism may occur as shown in FIG. 14(a). Therefore, as shown in FIG. 14(a), the focal position shifts in the secondary direction of the x and y directions on the substrate 101 (sample) surface, the beam becomes so-called elliptical at the focal position, and the irradiated beam becomes blurred. The direction and position shift amount of the astigmatism generated in the multi-primary electron beams 20 tend to be elliptical extending radially from the center of the multi-primary electron beams 20, but differs for each beam. Therefore, in order to correct such astigmatism, it is necessary to correct it for each individual beam. Therefore, by correcting the beam trajectory for each beam using the aberration corrector 220 in the first embodiment, the astigmatism can be corrected as shown in FIG. 14(b).

[0063] Fig. 15 is a diagram showing another example of astigmatism in the first embodiment. The direction of astigmatism generated in the multi primary electron beams 20 is not limited to the case of extending radially from the center of the multi primary electron beams 20 shown in Fig. 14(a). As shown in Fig. 15(a), it may also extend in the circumferential direction. Even in such a case, the astigmatism can be corrected as shown in Fig. 15(b) by correcting the beam trajectory for each beam using the aberration corrector 220 in the first embodiment.

[0064] Moreover, in the aberration corrector 220 in the first embodiment, distortion and astigmatism can be corrected simultaneously. Moreover, by applying the same potential (bias potential) to the eight electrodes 16 constituting the multipole element 13, the focus can also be corrected at the same time.

[0065] Here, the electrostatic lens 221 has three stages of electrode substrates in which an opening is formed through which the entire multiple primary electron beams 20 pass, and a control potential is applied to the middle stage electrode substrate. A GND potential is applied to the upper and lower stage electrode substrates. By adjusting the control potential of the middle stage electrode substrate, the focal positions of the multiple primary electron beams 20 can be corrected collectively. It is also preferable to arrange an electrostatic lens array so that the focal position of each beam can be individually controlled.

[0066] The image acquisition mechanism 150 acquires a secondary electron image of the pattern formed on the substrate 101 using the multi-primary electron beams 20 (multi-primary electron beams) whose aberrations have been corrected by the aberration corrector 220. Specifically, it operates as follows. The image acquisition mechanism 150 uses the multi-primary electron beams 20 to scan the substrate 101 on which a graphic pattern has been formed, and detects the multi-secondary electron beams 300 emitted from the substrate 101 due to irradiation with the multi-primary electron beams 20. The detection image data (measurement image: secondary electron image: inspection image) based on the detection signal of the secondary electrons from each measurement pixel 36 detected by the multi-detector 222 is output to the detection circuit 106 in the order of measurement. In the detection circuit 106, the analog detection data is converted to digital data by an A / D converter (not shown) and stored in the chip pattern memory 123. In this way, the image acquisition mechanism 150 acquires a measurement image of the pattern formed on the substrate 101. Then, for example, when the detection data for one chip 332 has been accumulated, the data is transferred to the comparison circuit 108 as chip pattern data together with information indicating each position from the position circuit 107.

[0067] In the reference image creating step, the reference circuit 112 (reference image creating unit) creates a reference image corresponding to the image to be inspected. The reference circuit 112 creates a reference image for each frame area based on the design data on which a pattern is formed on the substrate 101, or on the design pattern data defined in the exposure image data of the pattern formed on the substrate 101. For example, the mask die 33 is preferably used as the frame area. More specifically, the operation is as follows. First, the design pattern data is read from the storage device 109 through the control computer 110, and each figure pattern defined in the read design pattern data is converted into binary or multi-value image data.

[0068] Here, the figures defined in the design pattern data are, for example, rectangles and triangles as basic figures, and the figure data stored defines the shape, size, position, etc. of each pattern figure using information such as the coordinates (x, y) at the reference position of the figure, the length of the sides, and a figure code that serves as an identifier to distinguish the type of figure, such as a rectangle or triangle.

[0069] When the design pattern data that constitutes such graphic data is input to the reference circuit 112, it is expanded into data for each graphic, and the graphic code indicating the graphic shape of the graphic data, the graphic dimensions, etc. are interpreted. The graphic data is then expanded into binary or multi-value design pattern image data as a pattern to be placed within a grid having a predetermined quantized dimension as a unit, and output. In other words, the design data is read, the inspection area is virtually divided into grids having a predetermined dimension as a unit, the occupancy rate of the graphic in the design pattern is calculated for each grid, and n-bit occupancy data is output. For example, it is preferable to set one grid as one pixel. Then, 1 / 2 pixel is assigned to one pixel. 8 If a pixel has a resolution of (=1 / 256), a small area of ​​1 / 256 is allocated for the area of ​​the figure placed in the pixel to calculate the occupancy rate within the pixel. Then, the occupancy rate data is output to the reference circuit 112 as 8-bit data. The squares (inspection pixels) can be aligned with the pixels of the measurement data.

[0070] Next, the reference circuit 112 applies appropriate filtering to the design image data of the design pattern, which is image data of the graphic. Since the optical image data as the measurement image is in a state where a filter has been applied by the optical system, in other words, in an analog state that changes continuously, it is possible to match the measurement data by also applying filtering to the design image data, which is image data on the design side with image intensity (grayscale value) being a digital value. The image data of the created reference image is output to the comparison circuit 108.

[0071] FIG. 16 is a configuration diagram showing an example of the configuration in the comparison circuit in the first embodiment. In FIG. 16, the comparison circuit 108 includes storage devices 52 and 56 such as magnetic disk devices, an alignment unit 57, and a comparison unit 58. Each "unit" such as the alignment unit 57 and the comparison unit 58 includes a processing circuit, and the processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each "unit" may use a common processing circuit (the same processing circuit). Alternatively, different processing circuits (separate processing circuits) may be used. Input data or calculation results required in the alignment unit 57 and the comparison unit 58 are stored in a memory (not shown) or memory 118 each time.

[0072] In the comparison circuit 108, the transferred pattern image data (secondary electron image data) is temporarily stored in the storage device 56. The transferred reference image data is temporarily stored in the storage device 52.

[0073] In the alignment step, alignment unit 57 reads out a mask die image to be inspected and a reference image corresponding to the mask die image, and aligns the two images in units of sub-pixels smaller than pixels 36. For example, the alignment may be performed using the least squares method.

[0074] In the comparison step, the comparison unit 58 compares the mask die image (inspected image) with the reference image. The comparison unit 58 compares the two for each pixel 36 according to a predetermined judgment condition, and judges the presence or absence of a defect such as a shape defect. For example, if the gradation value difference for each pixel 36 is greater than the judgment threshold value Th, it is judged to be a defect. Then, the comparison result is output. The comparison result may be output to the storage device 109, the monitor 117, or the memory 118, or may be output from the printer 119.

[0075] In addition, the above-mentioned die-database inspection is not limited, and die-die inspection may be performed. When performing die-die inspection, images of mask dies 33 on which the same pattern is formed may be compared. Therefore, a mask die image of a partial area of ​​a wafer die 332 to be die (1) and a mask die image of a corresponding area of ​​another wafer die 332 to be die (2) are used. Alternatively, a mask die image of a partial area of ​​the same wafer die 332 may be used as the mask die image of die (1), and a mask die image of another part of the same wafer die 332 on which the same pattern is formed may be used as the mask die image of die (2) for comparison. In such a case, if one of the images of the mask die 33 on which the same pattern is formed is used as a reference image, inspection can be performed using a method similar to the above-mentioned die-database inspection.

[0076] That is, in the alignment step, the alignment unit 57 reads out the mask die image of the die (1) and the mask die image of the die (2), and aligns the two images in units of sub-pixels smaller than the pixel 36. For example, the alignment may be performed by the least squares method.

[0077] Then, as a comparison step, the comparison unit 58 compares the mask die image of the die (1) with the mask die image of the die (2). The comparison unit 58 compares the two for each pixel 36 according to a predetermined judgment condition, and judges the presence or absence of a defect, such as a shape defect. For example, if the gradation value difference for each pixel 36 is greater than the judgment threshold value Th, it is judged to be a defect. Then, the comparison result is output. The comparison result may be output to a storage device, monitor, or memory (not shown), or may be output from a printer.

[0078] In addition, in the above-mentioned examples of die-to-database inspection and die-to-die inspection, a comparison is made for each pixel, but the present invention is not limited to this. For example, it is also preferable to extract the contours of each figure pattern and determine that a defect exists when the distance between the contours exceeds a threshold value.

[0079] As described above, according to the first embodiment, the number of power supplies used for a multipole array such as the aberration corrector 220 can be reduced.

[0080] In the above description, a series of "circuits" includes a processing circuit, which may include an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each "circuit" may use a common processing circuit (the same processing circuit). Alternatively, different processing circuits (separate processing circuits) may be used. A program for executing the processor may be recorded on a recording medium such as a magnetic disk device, a magnetic tape device, a FD, or a ROM (read-only memory). For example, the position circuit 107, the comparison circuit 108, the reference image creation circuit 112, the stage control circuit 114, the aberration correction circuit 121, the lens control circuit 124, the blanking control circuit 126, and the deflection control circuit 128 may be composed of at least one of the processing circuits described above.

[0081] The above describes the embodiment with reference to specific examples. However, the present invention is not limited to these specific examples. In the example of Fig. 1, a case is shown in which multiple primary electron beams 20 are formed by a shaping aperture array substrate 203 from one beam irradiated from an electron gun 201 serving as one irradiation source, but the present invention is not limited to this. Multiple primary electron beams 20 may be formed by irradiating primary electron beams from multiple irradiation sources, respectively.

[0082] Further, although the description of the device configuration, control method, and other parts not directly necessary for the explanation of the present invention have been omitted, the required device configuration and control method can be appropriately selected and used.

[0083] In addition, all aberration correctors and multi-electron beam irradiation devices that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. [Explanation of symbols]

[0084] 2. Sample and hold circuit 3 Switch 4 Capacitors 5 Power supply 6. Operational Amplifiers 7 D / A Converter 10 First electrode substrate 11 Passing hole 12 Board body 13 Multipole 14 Second electrode substrate 15 Board body 16 electrodes 17 Passing hole 19 Irradiation position 20 Multi-primary electron beam 22 holes 29 Sub-irradiation area 33 Mask Die 34 Irradiation area 40 Insulating layer 42,44 Shield electrode 52,56 Storage device 57 Alignment section 58 Comparison section 100 Inspection Equipment 101 Substrate 102 Electron Beam Column 103 Examination Room 105 Stages 106 Detection circuit 107 Position circuit 108 Comparison circuit 109 Storage device 110 Control computer 112 Reference image creation circuit 114 Stage control circuit 117 Monitor 118 Memory 119 Printer 120 Bus 121 Aberration correction circuit 122 Laser length measurement system 123 Chip Pattern Memory 124 Lens control circuit 126 Blanking control circuit 128 Deflection control circuit 130 Sample and hold circuit board 132 Power supply circuit 142 Drive mechanism 144,146,148 DAC Amplifier 150 Image Acquisition Mechanism 160 Control Circuits 201 Electron Gun 202 Electromagnetic Lens 203 Shaped aperture array substrate 205 Electromagnetic Lens 206 Electromagnetic Lens 207 Electromagnetic Lens 208 Main deflector 209 Sub deflector 212 Blanking deflector 213 Limiting Aperture Substrate 214 E×B separator 216 Mirror 218 Deflector 220 Aberration corrector 221 Electrostatic Lens 222 Multi-detector 224 Electromagnetic Lens 300 Multi-Secondary Electron Beam 330 Inspection Area 332 Chips

Claims

1. A stage on which a substrate is placed; an emission source that emits multiple primary electron beams; a multipole array having a plurality of multipoles each arranged to surround a corresponding beam among the multiple primary electron beams at a position through which the corresponding beam passes; an objective deflector that collectively deflects the multiple primary electron beams that have passed through the multipole array to scan the substrate with the multiple primary electron beams; a plurality of first sample-and-hold circuits each having a capacitor and a switch arranged for each electrode of the plurality of multipoles, the first sample-and-hold circuits using the capacitor and the switch to hold a potential to be applied to the electrode; a plurality of power sources that apply a plurality of potentials to the plurality of first sample-and-hold circuits; a control circuit that controls the first sample and hold circuits so that the potentials applied to the first sample and hold circuits are held by a plurality of second sample and hold circuits selected from the first sample and hold circuits in synchronization with a return of the collective beam deflection by the objective deflector; a detector for detecting multiple secondary electron beams emitted as a result of the multiple primary electron beams being irradiated onto the substrate; A multi-electron beam inspection device comprising:

2. 2. The multi-electron beam inspection apparatus according to claim 1, wherein the number of said plurality of power sources is smaller than a value obtained by multiplying the number of said multiple primary electron beams by the number of electrodes of a multipole per beam.

3. 3. The multi-electron beam inspection apparatus according to claim 1, wherein the number of said plurality of power sources is smaller than the number of said multiple primary electron beams.

4. The control circuit further controls the plurality of power sources. the objective deflector scans a desired area for each beam by performing a plurality of line scan operations by repeating the collective beam deflection; 4. The multi-electron beam inspection device according to claim 1, wherein the control circuit switches the potentials of the plurality of power sources in synchronization with at least one of the plurality of line scanning operations.

5. applying a plurality of potentials to a plurality of first sample and hold circuits using capacitors and switches to hold potentials for application to the electrodes; holding the multiple potentials applied to the multiple first sample and hold circuits in multiple second sample and hold circuits selected from the multiple first sample and hold circuits in synchronization with a return of collective beam deflection of the multiple primary electron beams by an objective deflector that scans a substrate with the multiple primary electron beams by collective beam deflection of the multiple primary electron beams; applying the potentials held by the second sample-and-hold circuits to electrodes connected to the second sample-and-hold circuits in a plurality of multipoles arranged to surround corresponding beams among the multiple primary electron beams at positions through which the corresponding beams pass; A method for controlling a multipole array, comprising:

6. emitting multiple primary electron beams; a step of scanning a substrate placed on a stage with the multiple primary electron beams by using an objective deflector that performs collective beam deflection of the multiple primary electron beams; applying a plurality of potentials to a plurality of first sample and hold circuits using capacitors and switches to hold potentials for application to the electrodes; holding the potentials applied to the first sample and hold circuits in a plurality of second sample and hold circuits selected from the first sample and hold circuits in synchronization with a return of the collective beam deflection of the multiple primary electron beams by the objective deflector; applying the potentials held by the second sample-and-hold circuits to electrodes connected to the second sample-and-hold circuits in a plurality of multipoles arranged to surround corresponding beams among the multiple primary electron beams at positions through which the corresponding beams pass; correcting aberrations of the multiple primary electron beams individually using a multipole array having the plurality of multipoles; detecting multiple secondary electron beams emitted by irradiating the substrate with the multiple primary electron beams; A step of comparing a detection image based on the detected detection signal with a reference image and outputting the result; A multi-electron beam inspection method comprising:

Images