JP2019186140A - Multi-charged particle beam irradiation device and multi-charged particle beam irradiation method - Google Patents

Abstract

To provide a device capable of individually correcting at least distortion (distortion aberration) when radiating a multi-beam while using an optical system.SOLUTION: A multi-charged particle beam irradiation device comprises: a stage 105 to place a specimen thereon; an upper-stage electrode substrate 217 in which multiple first openings are formed at positions that charged particle beams pass, and to which a first potential is applied; a middle-stage electrode substrate 218 which is disposed at a downstream side of the upper-stage electrode substrate with respect to an advance direction of charged particle beams, in which multiple second openings corresponding to the multiple first openings are formed while including at least one second opening around a position shifted from a center of a corresponding first opening, and to which a second potential is applied; a lower-stage electrode substrate 219 which is disposed at a further downstream side of the middle-stage electrode substrate, in which multiple third openings are formed at positions similar to the multiple first openings, and to which the first potential is applied; and a charged particle beam optical system which irradiates the specimen with the charged particle beams passing the electrode substrates.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a multi-charged particle beam irradiation apparatus and a multi-charged particle beam irradiation method. For example, the present invention relates to an irradiation apparatus and method for correcting a positional deviation on a sample surface caused by aberration of an optical system that irradiates a multi-beam.

  In recent years, the circuit line width required for a semiconductor element has been increasingly narrowed as a large scale integrated circuit (LSI) is highly integrated and has a large capacity. These semiconductor elements use an original pattern pattern (also referred to as a mask or a reticle, hereinafter referred to as a mask) on which a circuit pattern is formed, and the pattern is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by forming a circuit.

  In addition, improvement in yield is indispensable for manufacturing an LSI that requires a large amount of manufacturing cost. However, as represented by a 1 gigabit class DRAM (Random Access Memory), the pattern constituting the LSI is on the order of submicron to nanometer. In recent years, with the miniaturization of LSI pattern dimensions formed on semiconductor wafers, the dimensions that must be detected as pattern defects have become extremely small. Therefore, it is necessary to improve the accuracy of a pattern inspection apparatus that inspects defects in ultrafine patterns transferred onto a semiconductor wafer. Another major factor that decreases the yield is a pattern defect of a mask used when an ultrafine pattern is exposed and transferred onto a semiconductor wafer by a photolithography technique. Therefore, it is necessary to improve the accuracy of a pattern inspection apparatus that inspects defects in a transfer mask used in LSI manufacturing.

  As an inspection method, a method of performing an inspection by comparing a measurement image obtained by imaging a pattern formed on a substrate such as a semiconductor wafer or a lithography mask with a measurement image obtained by imaging design data or the same pattern on the substrate. It has been known. For example, as a pattern inspection method, “die to die inspection” in which measurement image data obtained by imaging the same pattern at different locations on the same substrate is compared, or a design image based on design data on which a pattern is designed There is a “die to database (die-database) inspection” in which data (reference image) is generated and compared with a measurement image that is measurement data obtained by imaging a pattern. In the inspection method in such an inspection apparatus, a substrate to be inspected is placed on a stage, and the stage is moved, so that the light beam scans on the sample and the inspection is performed. The inspection target substrate is irradiated with a light beam by a light source and an illumination optical system. The light transmitted or reflected through the inspection target substrate is imaged on the sensor via the optical system. The image picked up by the sensor is sent to the comparison circuit as measurement data. The comparison circuit compares the measured data and the reference data according to an appropriate algorithm after the images are aligned, and determines that there is a pattern defect if they do not match.

  In the pattern inspection apparatus described above, an optical image is acquired by irradiating the inspection target substrate with a laser beam and capturing a transmission image or a reflection image thereof. In contrast, the development of an inspection apparatus that scans an inspection target substrate with an electron beam, detects secondary electrons emitted from the inspection target substrate upon irradiation of the electron beam, and acquires a pattern image. Is also progressing. In the inspection apparatus using an electron beam, development of an apparatus using a multi-beam is also progressing. In an apparatus using a multi-beam optical system, distortion (distortion aberration), off-axis astigmatism, and the like may occur. If an attempt is made to correct these corrections using an independent multipole lens, a multipole (for example, 8 poles) is required for each individual beam, and these are required for the number of beams. And a power supply circuit are required. Therefore, when the number of beams increases, it becomes difficult to mount on the apparatus. On the other hand, the lead position is individually connected to the intermediate electrode array of the multi-lens array in which Einzel lenses are arranged in a matrix, and the bias potential is individually controlled to individually correct the focal position and to correct the field curvature aberration. It has been proposed (see, for example, Patent Document 1). However, even in such a case, wiring and power supply circuits corresponding to at least the number of beams are required. Further, with such a configuration, it is difficult to correct individual distortion (distortion aberration) and off-axis astigmatism. Further, such a document discloses providing an astigmatism corrector having 8 poles per individual beam for astigmatism correction. The above-described problems are not limited to the multi-beam inspection apparatus, and may occur in the same way for all apparatuses that irradiate a multi-beam using an optical system such as a multi-beam drawing apparatus.

JP 60-042825 A

  Accordingly, one embodiment of the present invention provides an apparatus and method capable of individually correcting at least distortion (distortion aberration) when a multi-beam is irradiated using an optical system.

The multi-charged particle beam irradiation apparatus of one embodiment of the present invention is
A stage on which a sample is placed;
A plurality of first openings formed at positions through which the multi-charged particle beam passes, and an upper electrode substrate to which a first potential is applied;
A plurality of second openings that are arranged downstream of the upper electrode substrate with respect to the traveling direction of the multi-charged particle beam and that have at least one second opening centered at a position shifted from the center of the corresponding first opening; A plurality of second openings corresponding to the first openings, and a middle electrode substrate to which a second potential is applied;
A plurality of third openings are formed at the same position as the plurality of first openings, and are arranged on the downstream side of the intermediate electrode substrate with respect to the traveling direction of the multi-charged particle beam, and the first potential is applied. Lower electrode substrate,
A charged particle beam optical system that irradiates a sample with a multi-charged particle beam that has passed through an upper electrode substrate, a middle electrode substrate, and a lower electrode substrate;
It is provided with.

  Further, the shift amount of the center of at least one second opening is set to an amount for correcting the shift amount from the design position of the corresponding beam irradiated onto the sample surface.

  In addition, it is preferable that at least one second opening is formed in an elliptical shape.

  Alternatively, it is preferable that the at least one second opening is formed in a high-order rotationally symmetric shape.

The multi-charged particle beam irradiation method of one embodiment of the present invention includes:
Measuring the amount of deviation from the design position of each beam when a sample is irradiated with a multi-charged particle beam using a charged particle beam optical system;
An upper electrode substrate in which a plurality of first openings are formed at a position where the multi-charged particle beam passes; and an upper electrode substrate disposed downstream of the upper electrode substrate with respect to the traveling direction of the multi-charged particle beam. Corresponding to a plurality of first openings including at least one second opening centered at a position shifted from the center of the corresponding first opening so as to individually correct the shift amount for each beam. A middle stage electrode substrate in which a plurality of second openings are formed, and a plurality of second stage openings arranged on the downstream side of the middle stage electrode substrate with respect to the traveling direction of the multi-charged particle beam. Producing a lens array having a lower electrode substrate on which a third opening is formed;
Arranging a lens array in a charged particle beam optical system and irradiating the sample with a multi charged particle beam;
It is provided with.

  According to one embodiment of the present invention, at least distortion (distortion aberration) can be individually corrected when a multi-beam is irradiated using an optical system.

1 is a configuration diagram illustrating a configuration of a pattern inspection apparatus according to a first embodiment. FIG. 3 is a conceptual diagram showing a configuration of a molded aperture array substrate in the first embodiment. 3 is a diagram showing an example of a plurality of chip regions formed on the semiconductor substrate in the first embodiment. FIG. 6 is a diagram illustrating an example of a multi-beam irradiation region and a measurement pixel in Embodiment 1. FIG. FIG. 4 is a flowchart showing an example of a main process of the multi-beam inspection method in the first embodiment. 5 is a diagram illustrating an example of distortion in Embodiment 1. [FIG. 6 is a diagram illustrating an example of a top view of each electrode substrate of a correction lens array that corrects distortion in the first embodiment. FIG. FIG. 3 is a diagram illustrating an example of a cross-sectional view of each electrode substrate of a correction lens array that corrects distortion in the first embodiment. 6 is a diagram illustrating an example of astigmatism in the first embodiment. FIG. 6 is a diagram illustrating an example of a top view of each electrode substrate of a correction lens array for correcting distortion and astigmatism in Embodiment 1. FIG. FIG. 6 is a flowchart showing another example of the main process of the multi-beam inspection method in the first embodiment. FIG. 6 is a diagram for explaining high-order astigmatism in the first embodiment. FIG. 6 is a cross-sectional view showing a modification of the configuration of the correction lens array in Embodiment 1. FIG. 10 is a cross-sectional view illustrating another modification of the configuration of the correction lens array in the first embodiment. FIG. 10 is a cross-sectional view illustrating another modification of the configuration of the correction lens array in the first embodiment. FIG. 10 is a cross-sectional view illustrating another modification of the configuration of the correction lens array in the first embodiment. 6 is a configuration diagram illustrating an example of a configuration of a pattern drawing apparatus according to Embodiment 2. FIG. FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to a third embodiment.

  In the following embodiments, a configuration of a multi-beam using an electron beam will be described as an example of a multi-charged particle beam. However, the multi-charged particle beam is not limited to the electron beam, and may be a multi-beam using charged particles such as an ion beam. A multi-electron beam inspection apparatus will be described as an example of a multi-charged particle beam irradiation apparatus. However, the multi-charged particle beam irradiation apparatus is not limited to the inspection apparatus, and may be an apparatus that irradiates a multi-charged particle beam using an electromagnetic lens such as an electron beam drawing apparatus.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing the configuration of the pattern inspection apparatus according to the first embodiment. In FIG. 1, an inspection apparatus 100 that inspects a pattern formed on a substrate is an example of an electron beam inspection apparatus. The inspection apparatus 100 is an example of a multi-beam inspection apparatus. Furthermore, the inspection apparatus 100 is an example of a multi-electron beam image acquisition apparatus. The inspection apparatus 100 includes an image acquisition mechanism 150 and a control system circuit 160. The image acquisition mechanism 150 includes an electron beam column 102 (also referred to as an electron column) (an example of a multi-beam column), an examination room 103, a detection circuit 106, a chip pattern memory 123, a stage driving mechanism 142, and a laser length measurement system 122. It has. In the electron beam column 102, an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a correction lens array 220, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a main deflector 208, a sub deflector 209, A batch blanking deflector 212, a beam separator 214, projection lenses 224 and 226, a deflector 228, and a multi-detector 222 are disposed. The shaped aperture array substrate 203, the reduction lens 205, and the objective lens 207 constitute a primary multi-beam optical system (charged particle beam optical system) that irradiates the multi-beam 20 onto the substrate 101. The primary multi-beam optical system may further include an electron gun 201, an illumination lens 202, a limiting aperture substrate 206, a main deflector 208, a sub deflector 209, and / or a collective blanking deflector 212. The beam separator 214, the projection lenses 224 and 226, the deflector 228, and the multi-detector 222 constitute a secondary multi-beam optical system.

  An XY stage 105 that can move at least on the XY plane is disposed in the examination room 103. A substrate 101 (sample) to be inspected is disposed on the XY stage 105. The substrate 101 includes a mask substrate for exposure 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 graphic patterns. The chip pattern formed on the mask substrate for exposure is exposed and transferred a plurality of times onto the semiconductor substrate, whereby a plurality of chip patterns (wafer dies) are formed on the semiconductor substrate. Hereinafter, a case where the substrate 101 is a semiconductor substrate will be mainly described. For example, the substrate 101 is disposed on the XY stage 105 with the pattern formation surface facing upward. On the XY stage 105, a mirror 216 for reflecting laser length measurement laser light emitted from a laser length measurement system 122 arranged outside the examination room 103 is arranged. The multi-detector 222 is connected to the detection circuit 106 outside the electron beam column 102. The detection circuit 106 is connected to the chip pattern memory 123.

  In the control system circuit 160, a control computer 110 that controls the entire inspection apparatus 100 is connected via a bus 120 to a position circuit 107, a comparison circuit 108, a reference image creation circuit 112, a stage control circuit 114, a lens control circuit 124, and blanking. A control circuit 126, a deflection control circuit 128, a correction lens control circuit 130, a storage device 109 such as a magnetic disk device, a monitor 117, a memory 118, and a printer 119 are connected. The deflection control circuit 128 is connected to DAC (digital / analog conversion) amplifiers 144 and 146. The DAC amplifier 144 is connected to the main deflector 208, and the DAC amplifier 146 is connected to the sub deflector 209.

  The chip pattern memory 123 is connected to the comparison circuit 108. The XY stage 105 is driven by the drive mechanism 142 under the control of the stage control circuit 114. In the drive mechanism 142, for example, a drive system such as a three-axis (XY-θ) motor that drives in the X direction, Y direction, and θ direction in the stage coordinate system is configured, and the XY stage 105 is movable. Yes. As these X motor, Y motor, and θ motor (not shown), for example, step motors can be used. The XY stage 105 can be moved in the horizontal direction and the rotation direction by motors of XYθ axes. The moving position of the XY stage 105 is measured by the laser length measurement system 122 and supplied to the position circuit 107. The laser length measurement system 122 receives the reflected light from the mirror 216, and measures the position of the XY stage 105 based on the principle of laser interferometry. In the stage coordinate system, for example, an X direction, a Y direction, and a θ direction are set with respect to a plane orthogonal to the optical axis of the multi-primary electron beam.

  A high voltage power supply circuit (not shown) is connected to the electron gun 201, and an acceleration voltage is applied from a high voltage power supply circuit between a filament (not shown) in the electron gun 201 and the extraction electrode, and the voltage of a predetermined extraction electrode (Wernert) is adjusted. By application and heating of the cathode at a predetermined temperature, the electron group emitted from the cathode is accelerated and emitted as an electron beam 200. The illumination lens 202, the reduction lens 205, the objective lens 207, and the projection lenses 224 and 226 are, for example, electromagnetic lenses, and are controlled by the lens control circuit 124. The beam separator 214 is also controlled by the lens control circuit 124. The collective blanking deflector 212 and the deflector 228 are each composed of an electrode group of at least two poles, and are controlled by the blanking control circuit 126. The main deflector 208 is constituted by an electrode group having at least four electrodes, and is controlled by the deflection control circuit 128 via a DAC amplifier 144 arranged for each electrode. Similarly, the sub deflector 209 is composed of at least four electrode groups, and is controlled by the deflection control circuit 128 via the DAC amplifier 146 arranged for each electrode. The correction lens array 220 is controlled by the correction lens control circuit 130.

  Here, FIG. 1 shows a configuration necessary for explaining the first embodiment. The inspection apparatus 100 may normally have other necessary configurations.

FIG. 2 is a conceptual diagram showing the configuration of the molded aperture array substrate in the first embodiment. In FIG. 2, a two-dimensional horizontal (x direction) m ₁ row × vertical (y direction) n ₁ stage (m ₁ , n ₁ is an integer of 2 or more) hole (opening) is formed in the molded aperture array substrate 203. ) 22 are formed at a predetermined arrangement pitch in the x and y directions. In the example of FIG. 2, a case where a 23 × 23 hole (opening) 22 is formed is shown. Each hole 22 is formed of a rectangle having the same size and shape. Alternatively, it may be a circle having the same outer diameter. When a part of the electron beam 200 passes through each of the plurality of holes 22, the multi-beam 20 is formed. Here, an example is shown in which two or more holes 22 are arranged in both horizontal and vertical directions (x and y directions), but the present invention is not limited to this. For example, one of the horizontal and vertical directions (x and y directions) may be a plurality of rows and the other may be only one row. Further, the arrangement of the holes 22 is not limited to the case where the horizontal and vertical directions are arranged in a grid pattern as shown in FIG. For example, the holes in the vertical direction (y direction) k-th row and the (k + 1) -th row may be arranged so as to be shifted in the horizontal direction (x direction) by a dimension a. Similarly, the holes in the vertical (y direction) k + 1-th row and the k + 2-th row may be arranged so as to be shifted in the horizontal direction (x direction) by a dimension b.

  The image acquisition mechanism 150 acquires an inspection image of a graphic pattern from the substrate 101 on which the graphic pattern is formed using the multi-beam 20 using an electron beam. Hereinafter, the operation of the image acquisition mechanism 150 in the inspection apparatus 100 will be described.

  The electron beam 200 emitted from the electron gun 201 (emission source) illuminates the entire shaped aperture array substrate 203 almost vertically by the illumination lens 202. As shown in FIG. 2, a plurality of rectangular holes 22 (openings) are formed in the molded aperture array substrate 203, and the electron beam 200 illuminates a region including all of the plurality of holes 22. Each part of the electron beam 200 irradiated to the positions of the plurality of holes 22 passes through the plurality of holes 22 of the shaped aperture array substrate 203, for example, a plurality of rectangular electron beams (multi-beams) 20a to 20a. 20d (solid line in FIG. 1) (multi-primary electron beam) is formed.

The formed multi-beams 20a to 20d have their beam trajectories individually corrected by the correction lens array 220 as will be described later. The multi-beams 20a to 20d whose beam trajectories are individually corrected then form a crossover (C.O.), and after passing through the beam separator 214 arranged at the crossover position of each beam of the multi-beam 20. The lens is reduced by the reduction lens 205 and proceeds toward the central hole formed in the limiting aperture substrate 206. Here, when the entire multi-beams 20a to 20d are deflected all at once by the collective blanking deflector 212 arranged between the correction lens array 220 and the reduction lens 205, the center of the limiting aperture substrate 206 is centered. The position deviates from the hole and is blocked by the limiting aperture substrate 206. On the other hand, the multi-beams 20a to 20d that have not been deflected by the collective blanking deflector 212 pass through the central hole of the limiting aperture substrate 206 as shown in FIG. Blanking control is performed by turning ON / OFF the collective blanking deflector 212, and ON / OFF of the beam is collectively controlled. In this manner, the limiting aperture substrate 206 shields the multi-beams 20a to 20d deflected so as to be in the beam OFF state by the collective blanking deflector 212. Then, the inspection multi-beams 20a to 20d are formed by the beam group that has passed through the limiting aperture substrate 206 formed from when the beam is turned on to when the beam is turned off. The multi-beams 20a to 20d that have passed through the limiting aperture substrate 206 are focused on the surface of the sample 101 by the objective lens 207, and become a pattern image (beam diameter) with a desired reduction ratio. The main deflector 208 and the sub deflector 209 The entire multi-beam 20 that has passed through the limiting aperture substrate 206 is collectively deflected in the same direction, and is irradiated to the respective irradiation positions on the substrate 101 of each beam. In such a case, the main deflector 208 deflects the entire multi-beam 20 in a lump to the reference position of the mask die scanned by the multi-beam 20. In the first embodiment, for example, scanning is performed while continuously moving the XY stage 105. Therefore, the main deflector 208 further performs tracking deflection so as to follow the movement of the XY stage 105. Then, the sub-deflector 209 collectively deflects the entire multi-beam 20 so that each beam scans the corresponding area. The multi-beams 20 irradiated at a time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes 22 of the shaped aperture array substrate 203 by the desired reduction ratio (1 / a) described above. As described above, the electron beam column 102 irradiates the substrate 101 with a two-dimensional m ₁ × n _single multi-beam 20 at a time. A bundle of secondary electrons (multi-secondary electron beam 300) including reflected electrons corresponding to each beam of the multi-beam 20 from the substrate 101 due to the irradiation of the multi-beam 20 at a desired position on the substrate 101 ( (Dotted line in FIG. 1) is emitted.

  The multi-secondary electron beam 300 emitted from the substrate 101 is refracted by the objective lens 207 toward the center of the multi-secondary electron beam 300 and travels toward the central hole formed in the limiting aperture substrate 206. The multi-secondary electron beam 300 that has passed through the limiting aperture substrate 206 is refracted almost parallel to the optical axis by the reduction lens 205 and proceeds to the beam separator 214.

  Here, the beam separator 214 generates an electric field and a magnetic field in a direction orthogonal to a direction orthogonal to the traveling direction (optical axis) of the multi-beam 20. The electric field exerts a force in the same direction regardless of the traveling direction of the electrons. In contrast, the magnetic field exerts a force according to Fleming's left-hand rule. For this reason, the direction of the force acting on the electrons can be changed depending on the penetration direction of the electrons. The multi-beam 20 (primary electron beam) that enters the beam separator 214 from the upper side cancels out the force due to the electric field and the force due to the magnetic field, and the multi-beam 20 goes straight downward. On the other hand, the force due to the electric field and the force due to the magnetic field both act in the same direction on the multi-secondary electron beam 300 entering the beam separator 214 from below, and the multi-secondary electron beam 300 is inclined upward. Bend.

  The multi-secondary electron beam 300 bent obliquely upward is projected onto the multi-detector 222 while being refracted by the projection lenses 224 and 226. The multi-detector 222 detects the projected multi-secondary electron beam 300. The multi-detector 222 includes, for example, a diode-type two-dimensional sensor (not shown). Then, at the diode-type two-dimensional sensor position corresponding to each beam of the multi-beam 20, each secondary electron of the multi-secondary electron beam 300 collides with the diode-type two-dimensional sensor to generate electrons, and the secondary Electronic image data is generated for each pixel. Further, in order to perform scanning while continuously moving the XY stage 105, tracking deflection is performed as described above. Along with the movement of the deflection position accompanying such tracking deflection, the deflector 228 deflects the multi-secondary electron beam 300 so as to irradiate a desired position on the light receiving surface of the multi-detector 222.

FIG. 3 is a diagram showing an example of a plurality of chip regions formed on the semiconductor substrate in the first embodiment. In FIG. 3, when the substrate 101 is a semiconductor substrate (wafer), a plurality of chips (wafer dies) 332 are formed in a two-dimensional array in the inspection region 330 of the semiconductor substrate (wafer). A mask pattern for one chip formed on the exposure mask substrate is transferred to each chip 332 after being reduced to, for example, ¼ by an exposure apparatus (stepper) (not shown). Each chip 332 is divided into, for example, a plurality of mask dies 33 each having two-dimensional horizontal (x direction) m ₂ rows × vertical (y direction) n ₂ stages (m ₂ and n ₂ are integers of 2 or more). The In the first embodiment, the mask die 33 is a unit inspection region.

  FIG. 4 is a diagram illustrating an example of a multi-beam irradiation region and a measurement pixel in the first embodiment. In FIG. 4, each mask die 33 is divided into a plurality of mesh regions having a mesh shape, for example, with a multi-beam beam size. Each mesh region is a measurement pixel 36 (unit irradiation region). In the example of FIG. 4, the case of 8 × 8 multi-beams is shown. The irradiation area 34 that can be irradiated by one irradiation of the multi-beam 20 is (the x-direction size obtained by multiplying the pitch between the beams in the x-direction of the multi-beam 20 on the surface of the substrate 101 by the number of beams in the x-direction) × (the substrate 101 Y-direction size obtained by multiplying the pitch between beams in the y-direction of the multi-beam 20 on the surface by the number of beams in the y-direction). In the example of FIG. 4, the irradiation area 34 has the same size as the mask die 33. However, the present invention is not limited to this. The irradiation area 34 may be smaller than the mask die 33. Or it may be large. In the irradiation area 34, a plurality of measurement pixels 28 (beam irradiation positions at one shot) that can be irradiated by one irradiation of the multi-beam 20 are shown. In other words, the pitch between the adjacent measurement pixels 28 is the pitch between the beams of the multi-beam. In the example of FIG. 4, one sub-irradiation region 29 is configured by a square region that is surrounded by four adjacent measurement pixels 28 and includes one measurement pixel 28 among the four measurement pixels 28. In the example of FIG. 4, each sub-irradiation region 29 is configured with 4 × 4 pixels 36.

In the scanning operation in the first embodiment, scanning is performed for each mask die 33. In the example of FIG. 4, an example of scanning one mask die 33 is shown. When all the multi-beams 20 are used, m ₁ × n ₁ sub-irradiation regions 29 are arranged in the x and y directions (two-dimensionally) in one irradiation region 34. . The XY stage 105 is moved to a position where the first mask die 33 can be irradiated with the multi-beam 20. Then, while performing tracking deflection so as to follow the movement of the XY stage 105 by the deflector 208, the mask die 33 is scanned within the mask die 33 with the mask die 33 as the irradiation region 34 (scanning operation). To do. Each beam constituting the multi-beam 20 is in charge of one of the different sub-irradiation areas 29. In each shot, each beam irradiates one measurement pixel 28 corresponding to the same position in the assigned sub-irradiation area 29. In the example of FIG. 4, each beam is deflected by the deflector 208 to irradiate the first measurement pixel 36 from the bottom right in the assigned sub-irradiation region 29 in the first shot. Then, the first shot is irradiated. Subsequently, the deflector 208 collectively shifts the entire multi-beam 20 in the y direction by one measurement pixel 36 and shifts the beam deflection position to the right of the second stage from the bottom in the assigned sub-irradiation area 29 in the second shot. The first measurement pixel 36 is irradiated. Similarly, the third measurement pixel 36 from the right in the third row from the bottom in the assigned sub-irradiation region 29 is irradiated in the third shot. In the fourth shot, the first measurement pixel 36 from the right in the fourth row from the bottom in the assigned sub-irradiation region 29 is irradiated. Next, the deflector 208 collectively shifts the entire multi-beam 20 and shifts the beam deflection position to the position of the second measurement pixel 36 from the bottom right, and similarly, the measurement pixel 36 in the y direction. Are sequentially irradiated. Such an operation is repeated, and all the measurement pixels 36 in one sub-irradiation region 29 are sequentially irradiated with one beam. In one shot, multi-secondary electrons 300 corresponding to a plurality of beam shots of the same number as each hole 22 at a maximum by the multi-beams formed by passing through each hole 22 of the shaped aperture array substrate 203 at a time. Detected.

  As described above, the entire multi-beam 20 is scanned (scanned) using the mask die 33 as the irradiation region 34, but each beam scans one corresponding sub-irradiation region 29. When the scanning of one mask die 33 is completed, the next adjacent mask die 33 moves so as to be the irradiation region 34, and the next adjacent mask die 33 is scanned (scanned). Such an operation is repeated to advance scanning of each chip 332. Each time a shot of the multi-beam 20 is taken, secondary electrons are emitted from the irradiated measurement pixel 36 and detected by the multi-detector 282. In the first embodiment, the unit detection region size of the multi-detector 282 detects secondary electrons emitted upward from each measurement pixel 36 for each measurement pixel 36 (or for each sub-irradiation region 29).

  As described above, scanning using the multi-beam 20 enables a scanning operation (measurement) at a higher speed than when scanning with a single beam. Note that each mask die 33 may be scanned by a step-and-repeat operation, or each mask die 33 may be scanned while the XY stage 105 is continuously moved. When the irradiation area 34 is smaller than the mask die 33, the scanning operation may be performed while moving the irradiation area 34 in the mask die 33.

  When the substrate 101 is an exposure mask substrate, the chip area for one chip formed on the exposure mask substrate is divided into a plurality of stripe areas in a strip shape with the size of the mask die 33 described above, for example. Then, each mask die 33 may be scanned for each stripe region by the same scanning as that described above. Since the size of the mask die 33 on the exposure mask substrate is the size before transfer, it is four times the size of the mask die 33 on the semiconductor substrate. Therefore, when the irradiation region 34 is smaller than the mask die 33 on the exposure mask substrate, the scanning operation for one chip increases (for example, four times). However, since the pattern for one chip is formed on the exposure mask substrate, the number of scans can be reduced as compared with a semiconductor substrate on which more than four chips are formed.

  As described above, the image acquisition mechanism 150 uses the multi-beam 20 to scan the inspection substrate 101 on which the graphic pattern is formed, and from the inspection substrate 101 due to the irradiation of the multi-beam 20. The emitted secondary secondary electrons 300 are detected. Secondary electron detection data (measurement image: secondary electron image: image to be inspected) from each measurement pixel 36 detected by the multi-detector 282 is output to the detection circuit 106 in the order of measurement. In the detection circuit 106, analog detection data is converted into 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, at the stage where the detection data for one chip 332 is accumulated, it is transferred as chip pattern data to the comparison circuit 108 together with information indicating each position from the position circuit 107.

  The reference image creation circuit 112 generates a reference image for each mask die on the basis of design data used as a basis for forming a pattern on the substrate 101 or design pattern data defined in exposure image data of a pattern formed on the substrate 101. Create Specifically, it operates as follows. First, design pattern data is read from the storage device 109 through the control computer 110, and each graphic pattern defined in the read design pattern data is converted into binary or multivalued image data.

  Here, the figure defined in the design pattern data is, for example, a rectangle or triangle as a basic figure. For example, the coordinates (x, y) at the reference position of the figure, the length of the side, a figure such as a rectangle or a triangle Stored is graphic data that defines the shape, size, position, etc. of each pattern graphic with information such as a graphic code serving as an identifier for distinguishing species.

When design pattern data as such graphic data is input to the reference image creation circuit 112, it is expanded to data for each graphic, and graphic codes, graphic dimensions, etc. indicating the graphic shape of the graphic data are interpreted. Then, it is developed into a binary or multi-value design pattern image data as a pattern arranged in a grid having a grid of a predetermined quantization size as a unit, and is output. In other words, the design data is read, the occupancy ratio of the figure in the design pattern is calculated for each grid formed by virtually dividing the inspection area as a grid with a predetermined size as a unit, and the n-bit occupancy data is calculated. Output. For example, it is preferable to set one square as one pixel. If a resolution of 1/2 ⁸ (= 1/256) is given to one pixel, 1/256 small areas are allocated by the figure area arranged in the pixel, and the occupation ratio in the pixel is set. Calculate. Then, it is output to the reference circuit 112 as 8-bit occupation ratio data. Such squares (inspection pixels) may be aligned with the pixels of the measurement data.

  Next, the reference image creation circuit 112 performs an appropriate filter process on the design image data of the design pattern, which is graphic image data. Since the optical image data as the measurement image is in a state in which the filter is applied by the optical system, in other words, in an analog state that continuously changes, the image intensity (lightness value) is changed to the design image data that is the image data on the design side of the digital value. Also, it can be adjusted to the measurement data by applying the filtering process. The created image data of the reference image is output to the comparison circuit 108 and stored in a memory (not shown) in the comparison circuit 108.

  Then, the comparison circuit 108 (inspection unit) inspects the pattern formed on the substrate 101 using information on the multi-secondary electron beam 300 detected by the multi-detector 222. Specifically, it operates as follows.

  First, the comparison circuit 108 performs alignment between a mask die image serving as an inspection image and a mask die image serving as a reference image. For example, alignment is performed using a least square method. Here, for example, a mask die image is used as the inspection image.

  Next, the comparison circuit 108 compares the measurement image measured from the substrate 101 with the corresponding reference image. Specifically, the aligned image to be inspected and the reference image are compared for each pixel. Both are compared for each pixel according to a predetermined determination condition using a predetermined determination threshold value, and the presence or absence of a defect such as a shape defect is determined. For example, if the gradation value difference for each pixel is larger than the determination threshold Th, it is determined as a defect candidate. 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.

  In addition to the die-database inspection described above, a die-to-die inspection may be performed. When performing die-to-die inspection, measured image data obtained by imaging the same pattern at different locations on the same substrate 101 are compared. Therefore, the image acquisition mechanism 150 uses the multi-beam 20 (electron beam) to form one graphic pattern (first pattern) from the substrate 101 where the same graphic patterns (first and second graphic patterns) are formed at different positions. Measurement images that are secondary electron images of the other graphic pattern (second graphic pattern) and the other graphic pattern (second graphic pattern). In such a case, the acquired measurement image of one graphic pattern is a reference image, and the measurement image of the other graphic pattern is an inspection image. The acquired image of one graphic pattern (first graphic pattern) and the other graphic pattern (second graphic pattern) may be in the same chip pattern data or divided into different chip pattern data. Also good. The inspection method may be the same as the die-database inspection.

  Here, in such an apparatus that irradiates a multi-beam, distortion (distortion aberration), off-axis astigmatism, or the like may occur. As described above, when trying to correct these corrections using an independent multipole lens, a multipole (for example, 8 poles) is required for each individual beam, and these are required by the number of beams. A huge number of wires and power supply circuits are required. Therefore, when the number of beams increases, it becomes difficult to mount on the apparatus. Therefore, in the first embodiment, as will be described later, using the correction lens array 220 including three or more stages of electrode substrates, the distortion generated in each beam is individually corrected while reducing the number of wirings and power supply circuits. enable. Further, the correction lens array 220 may be improved so that off-axis astigmatism can be corrected in addition to distortion. This will be specifically described below.

  FIG. 5 is a flowchart showing an example of main steps of the multi-beam inspection method according to the first embodiment. 5, the multi-beam inspection method according to the first embodiment includes a distortion amount measurement step (S102), a distortion correction lens array manufacturing step (S104), an astigmatism measurement step (S106), a distortion and astigmatism correction lens. A series of steps of an array remanufacturing step (S108), a distortion and astigmatism measurement step (S110), a determination step (S112), and a pattern inspection step (S114) are performed. A series of steps shown in FIG. 5 are also main steps of the multi-beam irradiation method in the first embodiment.

  As a distortion amount measurement step (S102), an electron beam optical system having an objective lens 207 is used to measure the deviation amount of each beam from the design position when the sample is irradiated with the multi-beam 20. Specifically, the measurement is performed as follows. First, in the configuration shown in FIG. 1, evaluation in which a resist is applied instead of the substrate 101 to be inspected in a state where the correction lens array 220 is not operating, that is, in a state where no deflection is applied to the electron beam trajectory. The substrate is placed on the XY stage 105 and the evaluation substrate is irradiated (exposed) with the multi-beam 20. Then, the evaluation substrate irradiated with the multi-beam 20 is developed, and the position of the irradiation pattern (beam irradiation position) formed by irradiation with each beam is measured by the position detector. With one beam, when the size of the irradiation pattern is smaller than the measurement limit of the position detector, a plurality of shots are performed while shifting the pixel 36, and an irradiation pattern having a size larger than the measurement limit of the position detector is obtained. What is necessary is just to form. By measuring the edge positions on both sides of the irradiation pattern and determining the center position, the irradiation position of the beam can be measured. Alternatively, an irradiation position of each beam may be measured by arranging a mark (not shown) on the XY stage 105, scanning the mark for each beam, and measuring the secondary electron image. Then, the amount of deviation of the irradiation position of each beam from the design position of each beam when the evaluation beam (sample) is irradiated with the multi-beam 20 is measured as a distortion amount.

  FIG. 6 is a diagram illustrating an example of distortion in the first embodiment. In the example of FIG. 6, a case where 5 × 5 multi-beams 20 are used is shown. If the plurality of holes 22 of the molded aperture array substrate 203 are formed in a matrix at predetermined pitches in the x and y directions, ideally, the substrate 101 is irradiated as shown in FIG. The irradiation positions 10 of the multi-beams 20 should also be arranged in a matrix at a predetermined reduction rate. However, when an optical system such as an electromagnetic lens such as the illumination lens 202, the reduction lens 205, and / or the objective lens 207 is used, distortion (distortion aberration) occurs as shown in FIG. The shape of the distortion takes a distribution called barrel type or pin cushion type depending on conditions. In general, the distortion of the magnetic lens causes a shift in the rotational direction in addition to the radial direction. FIG. 6B shows an example under conditions where no rotation component occurs. Even if there is a certain degree of tendency, the direction of the distortion and the amount of displacement generated in the multi-beam 20 are different for each beam. Therefore, in order to correct such distortion, it is necessary to correct for each individual beam. Therefore, in the first embodiment, the correction lens array 220 capable of correcting the beam trajectory for each beam is manufactured.

  As a distortion correction lens array manufacturing step (S104), a correction lens array for correcting distortion is manufactured.

FIG. 7 is a diagram illustrating an example of a top view of each electrode substrate of the correction lens array for correcting distortion in the first embodiment.
FIG. 8 is a diagram illustrating an example of a cross-sectional view of each electrode substrate of the correction lens array for correcting distortion in the first embodiment. The correction lens array 220 includes three or more stages of electrode substrates. In the example of FIGS. 7 and 8, a correction lens array 220 configured by three-stage electrode substrates of an upper electrode substrate 217, a middle electrode substrate 218, and a lower electrode substrate 219 is illustrated. The upper electrode substrate 217, the middle electrode substrate 218, and the lower electrode substrate 219 are formed using a conductive material. Alternatively, a conductive material film may be formed on the surface of the insulating material. In the example of FIGS. 7 and 8, a case where 3 × 3 multi-beams 20 are used is shown. The middle electrode substrate 218 is disposed with a gap G1 on the downstream side of the upper electrode substrate 217 with respect to the traveling direction of the multi-beam 20. The lower electrode substrate 219 is disposed with a gap G2 on the downstream side of the intermediate electrode substrate 218 with respect to the traveling direction of the multi-beam 20. In the upper electrode substrate 217, the middle electrode substrate 218, and the lower electrode substrate 219, a plurality of openings 11 (or 12 or 13) are formed at positions where the multi-beam 20 passes. A ground potential (first potential) is applied to the upper electrode substrate 217 and the lower electrode substrate 219. Further, for example, a positive potential (second potential) is applied to the middle electrode substrate 218. The plurality of openings 11 (first opening) of the upper electrode substrate 217 and the plurality of openings 13 (third opening) of the lower electrode substrate 219 are arranged such that the center of the opening comes to the passage position of each corresponding beam. Is formed. In the example of FIG. 1, the case of being arranged immediately below the shaping aperture array 203 is shown. In other words, the lower electrode substrate 219 has a plurality of openings at the same positions as the plurality of openings 11 of the upper electrode substrate 217. 13 is formed. In such a case, the plurality of openings 11 and 13 may be formed with the arrangement pitch P of the plurality of holes 22 formed in the shaping aperture array 203.
When the electrode substrates 217 and 219 are grounded and a positive potential is applied to the electrode substrate 218, the openings of the electrode substrates 217 and 219 corresponding to one opening of the electrode substrate 218 (corresponding to the same electron beam trajectory) are respectively circular. Thus, when the central axes coincide with each other, the electric field generated between the electrodes acts as a so-called Einzel lens and an electrostatic convex lens for electrons. On the other hand, when the opening of the electrode substrate 218 is deviated, an electric field perpendicular to the beam traveling trajectory oriented in the direction of the deviation is generated, thereby deflecting the electron beam trajectory.

  On the other hand, although the plurality of openings 12 corresponding to the plurality of openings 11 are formed in the middle electrode substrate 218, the plurality of openings 12 are shifted from the center of the corresponding openings 11. It includes at least one opening 12 that is central. The shift amount of the center of at least one opening 12 is set to an amount for correcting the shift amount from the design position of the corresponding beam irradiated onto the evaluation substrate (sample) surface. In addition, the direction in which the center of at least one opening 12 is shifted is set to correct the deviation from the design position of the corresponding beam irradiated onto the evaluation substrate (sample) surface. In FIG. 7, the dotted lines of the middle electrode substrate 218 indicate the positions of the plurality of openings 11 of the upper electrode substrate 217. In the example of FIG. 6, for example, the beams arranged in the x and y directions (vertical and horizontal) passing through the center of the entire multi-beam 20 are distorted so as to be shifted toward the center as the distance from the center increases. Further, the 45-degree and 135-degree aligned beams passing through the center of the entire multi-beam 20 are distorted so as to move away from the center as the distance from the center increases. Therefore, in the example of FIG. 7, the beams arranged in the x and y directions (vertical and horizontal) passing through the center of the entire multi-beam 20 shift the center of the opening 12 in the direction and amount away from the center as the distance from the center increases. Further, the beams arranged in the oblique directions of 45 degrees and 135 degrees passing through the center of the entire multi-beam 20 shift the center of the opening 12 toward the direction and amount closer to the center as the distance from the center increases. Here, since the distortion amount of the individual beam is measured, the direction and the shift amount for correcting the distortion amount are set for each opening 12.

  The electrons passing through the opening 11 of the upper electrode substrate 217 are shifted in the orbit, for example, toward the center by the opening 12 of the middle electrode substrate 218 whose center is shifted to the center. Then, after passing through the opening 13 of the lower electrode substrate 219, the electron trajectory advances obliquely inward. Conversely, when the opening 12 of the middle electrode substrate 218 whose center is shifted outward is formed, the trajectory of electrons is shifted outward. Then, after passing through the opening 13 of the lower electrode substrate 219, the electron trajectory proceeds obliquely outward. Therefore, by adjusting the direction and amount to be corrected by shifting the opening 12 in accordance with the positional deviation amount of the individual beam, the single potential is applied to the intermediate electrode substrate 218 for each beam while being adjusted. It can be reduced by correcting the distortion individually.

Here, the arrangement pitch P of the plurality of openings 11 and 13 of the upper electrode substrate 217, the diameter D1 of the plurality of openings 11, the diameter D2 of the plurality of openings 12, and the diameter D3 of the plurality of openings 13 The relationship between the gap G1 between the upper electrode substrate 217 and the middle electrode substrate 218 and the gap G2 between the middle electrode substrate 218 and the lower electrode substrate 219 is preferably set as follows. The diameter D 1 of the plurality of openings 11, the diameter D 2 of the plurality of openings 12, and the diameter D 3 of the plurality of openings 13 are formed larger than the size of the holes 22 formed in the molded aperture array substrate 203. Therefore, the multi-beam 20 is not reshaped when passing.
(1) P> G1, G2
(2) P-D1, P-D2, P-D3> G1, G2

  By satisfying the relations of the expressions (1) and (2), the influence of the electric field of the adjacent beam can be reduced. In addition, since the shift amount of the plurality of openings 12 of the middle-stage electrode substrate 218 is smaller than the diameter D2, this relationship can be ignored. When the diameter D1 of the plurality of openings 11, the diameter D2 of the plurality of openings 12, and the diameter D3 of the plurality of openings 13 are, for example, 100 μmφ and the gaps G1 and G2 are 100 μm, an evaluation substrate (sample) In order to correct the positional deviation of 10 nm on the surface, it is sufficient to set the shift amount of the opening 12 to, for example, 5 to 10 μm (for example, 7 μm) and to apply a potential of about 5 to 100 V (for example, 10 V) to the intermediate electrode substrate 218. .

  As an astigmatism measurement step (S106), a correction lens array for correcting the manufactured distortion is mounted on the inspection apparatus 100, and astigmatism is measured when the distortion is corrected using the correction lens array.

  FIG. 9 is a diagram illustrating an example of astigmatism in the first embodiment. The example of FIG. 9 shows a case where eight beams in the oblique direction are omitted from the 5 × 5 multi-beams 20. Ideally, each beam is irradiated in a circle. However, astigmatism may occur by incorporating a correction lens array for correcting the manufactured distortion into the inspection apparatus 100. There may also be original astigmatism caused by using an optical system such as an electromagnetic lens such as illumination lens 202, reduction lens 205, and / or objective lens 207. Therefore, as shown in FIG. 9, the focal position shifts in the secondary direction of the x and y directions on the sample surface, the beam becomes so-called elliptical at the focal position, and the irradiated beam is blurred. The direction of astigmatism and the amount of positional deviation generated in the multi-beam 20 are different for each beam even though there is a certain tendency. Therefore, in order to correct such astigmatism, it is necessary to correct each individual beam. Therefore, in the first embodiment, in addition to distortion, astigmatism is also added to the correction items of the correction lens array 220 so that the beam trajectory can be corrected for each beam. However, the present invention is not limited to this. The correction target of the correction lens array 220 may be only distortion.

  In the distortion and astigmatism correction lens array remanufacturing step (S108), a correction lens array for correcting distortion and astigmatism is remanufactured.

  FIG. 10 is a diagram illustrating an example of a top view of each electrode substrate of the correction lens array for correcting distortion and astigmatism in the first embodiment. An example of a cross-sectional view of each electrode substrate of the correction lens array for correcting distortion and astigmatism in the first embodiment is the same as FIG. The configurations of the upper electrode substrate 217 and the lower electrode substrate 219 are the same as those in FIGS. On the other hand, the shape of the plurality of openings 12 of the middle electrode substrate 218 is formed in an elliptical shape distorted in the direction for correcting astigmatism. In the example of FIG. 9, as the distance from the center of the multi-beam 20 increases, the size is reduced in the radial direction and is distorted in an elliptical shape in which the size is increased in the direction orthogonal to the radial direction. Therefore, in the example of FIG. 10, as the distance from the center of the multi-beam 20 is increased, the elliptical shape is formed such that the size increases in the radial direction and decreases in the direction orthogonal to the radial direction. Since the astigmatism is a blur of the beam (focal position shift), it is not necessary to shift the center of the aperture. Therefore, at the center position of the opening for distortion correction, according to the size of the astigmatism, the opening shape may be formed from a circular shape to an elliptical shape having a major axis and a minor axis that correct such astigmatism.

  In the distortion and astigmatism measurement step (S110), a correction lens array 220 for correcting the reconstructed distortion and astigmatism is mounted on the inspection apparatus 100, and the distortion and astigmatism are measured using the correction lens array 220. .

  In the determination step (S112), it is determined whether or not the measured distortion and astigmatism are within an allowable range. If the lens is still out of the allowable range, the correction lens returns to the distortion and astigmatism correction lens array remanufacturing step (S108), and the shape and the like are adjusted so as to further correct the distortion and astigmatism until it falls within the allowable range. The array 220 may be manufactured.

  As the pattern inspection step (S114), the inspection apparatus 100 inspects the defect of the pattern formed on the substrate 101 (sample) using the multi-beam 20 that has passed through the correction lens array 220. Specifically, the multi-beam 20 that has passed through the correction lens array 220 is irradiated onto the substrate 101 (sample) using a primary multi-beam optical system. Then, as described above, the multi-secondary electron beam 300 generated by the irradiation of the multi-beam 20 onto the substrate 101 is guided to the multi-detector 222 by the secondary multi-beam optical system and detected by the multi-detector 222. Pattern inspection is performed using the secondary electron image.

  Here, in the above-described example, the case where the correction lens array for correcting the distortion is once created and then the astigmatism measurement is performed, and the correction lens array for correcting the distortion and the astigmatism is newly manufactured is described. It is not limited to.

  FIG. 11 is a flowchart showing another example of the main process of the multi-beam inspection method according to the first embodiment. In FIG. 11, the multi-beam inspection method according to the first embodiment includes a distortion amount measuring step (S102), an astigmatism simulation step (S105), a distortion and astigmatism correction lens array manufacturing step (S107), a distortion and an astigmatism. A series of steps of a point measurement step (S110), a determination step (S112), and a pattern inspection step (S114) are performed. Each series of steps shown in FIG. 11 is also a main step of the multi-beam irradiation method in the first embodiment.

  The content of the distortion amount measurement step (S102) is the same as that described above.

  In the astigmatism simulation step (S105), the astigmatism generated when the distortion is corrected by the correction lens array is obtained by simulation using the measured distortion amount.

  In the distortion and astigmatism correction lens array manufacturing step (S107), a correction lens array 220 for correcting distortion and astigmatism is manufactured. As described above, the shift amount and the direction of the opening center of the opening 12 of the middle electrode substrate 218 are set to the shift amount and the direction for correcting the measured distortion amount. Further, the shape of the opening 12 is set to an elliptical shape having a major axis and a minor axis, in which the astigmatism is corrected, according to the size of the astigmatism obtained by simulation. The contents of the distortion and astigmatism measurement process (S110), the determination process (S112), and the pattern inspection process (S114) are the same as those described above.

  As described above, by predicting astigmatism through simulation, the number of times the correction lens array 220 is manufactured can be reduced.

  FIG. 12 is a diagram for explaining high-order astigmatism in the first embodiment. In the above-mentioned example, as shown in FIG. 12A, the elliptical astigmatism having the secondary rotational symmetry of the x and y axes has been described. However, the present invention is not limited to this. As shown in FIG. 12B, astigmatism having a third-order rotational symmetry having a shape similar to a triangle may also occur. In the correction lens array 220 according to the first embodiment, the shape of the opening 12 of the middle electrode substrate 218 is not only the shape of the second-order rotational symmetry but also the shape of the third-order or higher-order rotational symmetry. Is also suitable. Thereby, it is possible to correct and reduce astigmatism having third-order or higher order rotational symmetry. Furthermore, a plurality of rotational symmetries can be added to the aperture deformation accuracy distribution so as to generate an electric field having a plurality of rotational symmetries.

  FIG. 13 is a cross-sectional view showing a modified example of the configuration of the correction lens array in the first embodiment. As shown in FIG. 8, the correction lens array 220 described above has been described with respect to the case where the upper electrode substrate 217, the middle electrode substrate 218, and the lower electrode substrate 219 are configured with three electrode substrates. It is not a thing. Furthermore, you may make it comprise with a multistage electrode board | substrate. In the example of FIG. 13, a first-stage electrode substrate 317 to which a ground potential is applied, a second-stage electrode substrate 318 to which a positive potential is applied and the center of the opening is shifted in accordance with the positional deviation, and the ground A third-stage electrode substrate 319 to which a potential is applied, for example, a fourth-stage electrode substrate 320 to which a positive potential is applied and the center of the opening is shifted in accordance with the position shift, and a fifth-stage electrode substrate to which a ground potential is applied. In this example, the electrode substrate 321 and the five-stage electrode substrate 321 are used. By providing a two-stage electrode substrate that shifts the opening center between the second-stage electrode substrate 318 and the fifth-stage electrode substrate 321 across the electrode substrate to which the ground potential is applied, the track is divided into two times. Can be corrected. Therefore, the shift amount in each electrode substrate of the two-stage electrode substrate that shifts the opening center can be reduced. Thereby, the magnitude of other aberrations that can be caused by the correction of the trajectory of the individual beam due to the shift of the aperture center can be reduced. Of course, the number of stages is not limited to five, and more stages may be used. As the number of multistages increases, the shift amount of the opening center per stage can be reduced.

FIG. 14 is a cross-sectional view showing another modification of the configuration of the correction lens array in the first embodiment.
FIG. 15 is a cross-sectional view showing another modification of the configuration of the correction lens array according to the first embodiment.
FIG. 16 is a cross-sectional view illustrating another modification of the configuration of the correction lens array according to the first embodiment. In the example of FIG. 14, the above-described correction lens array 220 is arranged in two stages. As shown in the example of FIG. 14, the two-stage correction lens array is arranged at a certain distance in the electron beam traveling direction, so that the two-stage correction lens array is deflected in different directions along the trajectory. The irradiation position of the electron beam on the sample surface can be changed without changing the crossover position. The number of correction lens arrays may be two or more.
Here, as shown in FIGS. 15 and 16, a plurality of virtual electron source images (referred to as effective multi electron sources) are formed downstream of the multi-electron source or the aperture array, and the images are displayed on the sample surface. In the case of an effective multi-electron source method, the above-described crossover position is overlapped with each multi-electron source or the position where ideal orbits of electron beams from the effective multi-electron source overlap (multi-electron This is called the crossover position of the source trajectory.

  As described above, according to the first embodiment, when multi-beam irradiation is performed using an optical system, at least distortion (distortion aberration) can be individually corrected and reduced using a small number of wirings and power supply circuits. Furthermore, astigmatism can be individually corrected and reduced.

Embodiment 2. FIG.
In the first embodiment, the inspection apparatus has been described as an example of a multi-beam irradiation apparatus that can individually correct distortion (distortion aberration) and astigmatism. In Embodiment 2, a drawing apparatus will be described as an example of a multi-beam irradiation apparatus.

  FIG. 17 is a configuration diagram illustrating an example of the configuration of the pattern drawing apparatus according to the second embodiment. In FIG. 17, a drawing apparatus 700 for drawing a pattern on a substrate is an example of an electron beam drawing apparatus. The drawing apparatus 700 is an example of a multi-beam drawing apparatus. Furthermore, the drawing apparatus 700 is an example of a multi-electron beam image acquisition apparatus. The drawing apparatus 700 includes a drawing mechanism 750 and a control system circuit 760. The drawing apparatus 700 includes an electron beam column 702 (also referred to as an electron column) (an example of a multi-beam column), a drawing chamber 703, a stage drive mechanism 142, and a laser length measurement system 122. In the electron beam column 702, an electron gun 201, an illumination lens 202, a correction lens array 220, a shaping aperture array substrate 203, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a main deflector 208, a sub deflector 209, And a blanking deflector 212 is disposed. 17, the configuration of the drawing mechanism 750 is the configuration of the primary multi-beam optical system of the image acquisition mechanism 150 of FIG. 1 except that the arrangement positions of the shaping aperture array substrate 203 and the correction lens array 220 are reversed. It is the same.

  An XY stage 105 that can move at least on the XY plane is disposed in the drawing chamber 703. On the XY stage 105, a substrate 101 (sample) to be drawn is arranged. The substrate 101 is held on the XY stage 105 by, for example, three-point support (not shown). The substrate 101 includes an exposure mask for manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured. Further, the substrate 101 includes mask blanks to which a resist is applied and nothing is drawn yet.

  In the control system circuit 760, the control computer 110 that controls the entire drawing apparatus 700 is connected via the bus 120 to the position circuit 107, the stage control circuit 114, the lens control circuit 124, the blanking control circuit 126, the deflection control circuit 128, and the correction. The lens control circuit 130 is connected to a storage device 109 such as a magnetic disk device, a monitor 117, a memory 118, and a printer 119. The deflection control circuit 128 is connected to DAC (digital / analog conversion) amplifiers 144 and 146. The DAC amplifier 144 is connected to the main deflector 208, and the DAC amplifier 146 is connected to the sub deflector 209.

  The XY stage 105 is the same as that in FIG. 1 in that it is driven by the drive mechanism 142 under the control of the stage control circuit 114. The moving position of the XY stage 105 is measured by the laser length measuring system 122 and is supplied to the position circuit 107 as in FIG.

In the example of FIG. 17, the electron beam 200 emitted from the electron gun 201 (emission source) illuminates the entire correction lens array 220 almost vertically by the illumination lens 202. Diameter D1 of the plurality of openings 11 of the upper electrode substrate 217 constituting the correction lens array 220, diameter D2 of the plurality of openings 12 of the middle electrode substrate 218, and diameter D3 of the plurality of openings 13 of the lower electrode substrate 219 Is formed larger than the size of the hole 22 formed in the molded aperture array substrate 203. Therefore, each part of the electron beam 200 irradiated to the positions of the plurality of openings 11 passes through the plurality of openings 11 of the upper electrode substrate 217, for example. ) Is formed. The temporary multi-beam passes through the upper electrode substrate 217, the middle electrode substrate 218, and the lower electrode substrate 219 in order, so that the beam trajectory is individually set by the correction lens array 220 including these three electrode substrates. It is corrected. The provisional multi-beams whose beam trajectories are individually corrected then pass through the plurality of holes 22 of the shaped aperture array substrate 203, for example, a plurality of rectangular electron beams (multi-beams) 20a to 20d (FIG. 13). Solid line) (multi-primary electron beam) is formed. The formed multi-beams 20 a to 20 d are then reduced by the reduction lens 205, and a crossover (C.O.) is formed in the central hole formed in the limiting aperture substrate 206. Ideally, the trajectory near the center of the electron beam that has passed through each aperture of the shaped aperture array substrate 203 (the trajectory of each beam) passes through the region of the ideal crossover image size at the crossover position. When the illumination lens 202 and the reduction lens 205 have aberration, the trajectory passing position of each beam deviates from this ideal crossover image region at the crossover position. By correcting the trajectory by the correction lens array 202, aberrations such as spherical aberration and astigmatism in crossover imaging by the illumination lens 202 and the reduction lens 205 can be corrected, and the deviation of the trajectory can be reduced.
Here, when the entire multi-beams 20a to 20d are deflected collectively by the collective blanking deflector 212 disposed between the shaping aperture array substrate 203 and the reduction lens 205, the center of the limiting aperture substrate 206 is obtained. The position is deviated from the hole and is shielded by the limiting aperture substrate 206. On the other hand, the multi-beams 20a to 20d that have not been deflected by the collective blanking deflector 212 pass through the central hole of the limiting aperture substrate 206 as shown in FIG. Blanking control is performed by turning ON / OFF the collective blanking deflector 212, and ON / OFF of the beam is collectively controlled. In this manner, the limiting aperture substrate 206 shields the multi-beams 20a to 20d deflected so as to be in the beam OFF state by the collective blanking deflector 212. Then, the drawing multi-beams 20a to 20d are formed by the beam group that has passed through the limiting aperture substrate 206 formed from when the beam is turned on to when the beam is turned off. The multi-beams 20a to 20d that have passed through the limiting aperture substrate 206 are focused on the surface of the substrate 101 by the objective lens 207, and become a pattern image (beam diameter) with a desired reduction ratio. The main deflector 208 and the sub deflector 209 The entire multi-beam 20 that has passed through the limiting aperture substrate 206 is collectively deflected in the same direction and is irradiated onto the irradiation positions on the substrate 101 of each beam, whereby a desired pattern is drawn on the substrate 101. .

  As described above, according to the second embodiment, as in the first embodiment, when multi-beam irradiation is performed using an optical system, astigmatism of crossover imaging is performed using a small number of wires and a power supply circuit. It is possible to correct aberrations such as spherical aberration, in which the trajectory of the electron beam that has passed through each aperture of the shaped aperture array substrate 203 is shifted at the crossover position.

Embodiment 3 FIG.
In Embodiment 3, in addition to correcting distortion (distortion aberration) and astigmatism individually, another configuration of a multi-beam irradiation apparatus capable of further reducing spherical aberration will be described. In Embodiment 3, a drawing apparatus using a doublet lens will be described as an example.

  FIG. 18 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the third embodiment. In FIG. 18, the drawing apparatus 500 includes a drawing mechanism 550 and a control system circuit 560. The drawing apparatus 500 is an example of a multi charged particle beam irradiation apparatus and an example of a multi charged particle beam drawing apparatus. The drawing mechanism 550 includes an electron column 502 and a drawing chamber 503. In the electron column 502, an electron gun 601, an illumination lens 602, a pre-molded aperture array substrate 624, a correction lens array 220, electromagnetic lenses 612 and 614 constituting a doublet lens, a limiting aperture member 616, a correction lens array 221 and a molding An aperture array substrate 603, a blanking aperture array mechanism 604, a reduction lens 605, a limiting aperture member 606 (blanking aperture), an objective lens 607, and a deflector 608 are disposed. An XY stage 505 is disposed in the drawing chamber 503. On the XY stage 505, a sample 501 such as a mask to be a drawing target substrate at the time of drawing is arranged. The sample 501 is held on the XY stage 505 by, for example, three-point support (not shown). The sample 501 includes an exposure mask for manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured. Further, the sample 501 includes mask blanks to which a resist is applied and nothing is drawn yet.

  The correction lens array 220 is located near the blanking aperture array mechanism 604 side opposite to the electron gun 601 side with respect to the pre-molded aperture array substrate 624 (the first molded aperture array substrate or the first aperture array substrate). Be placed. For example, it is disposed between the pre-molded aperture array member 624 and the electromagnetic lens 612 on the upstream side of the optical axis constituting the doublet lens. The arrangement order of the correction lens array 220 and the pre-molded aperture array substrate 624 may be reversed. As shown in FIG. 7 (or FIG. 10) and FIG. 8, the correction lens array 220 is composed of, for example, a three-stage electrode substrate.

A doublet lens constituted by the electromagnetic lens 612 (first electromagnetic lens) and the electromagnetic lens 614 (second electromagnetic lens) is disposed between the pre-molded aperture array substrate 624 and the molded aperture array substrate 604. In the example of FIG. 18, it is arranged between the correction lens array 220 and the correction lens array 221. The electromagnetic lens 612 and the electromagnetic lens 614 are excited to have the same axial magnetic field sign and the same magnitude.
Here, the electromagnetic lenses 612 and 614 need only satisfy the condition that the magnetic field having the lens effect satisfies the condition, and the arrangement of the structures such as the ferromagnetic bodies and the coils constituting the electromagnetic lens is the first molded aperture array member or the later-described arrangement. Need not be placed between the second shaping aperture array.

  The limiting aperture member 616 is disposed between the electromagnetic lens 612 and the electromagnetic lens 614 at the multi-beam focusing point position. The limiting aperture member 616 is grounded.

  In addition, the molded aperture array substrate 603 (second molded aperture array substrate or second aperture array substrate) is disposed on the XY stage 505 side with respect to the doublet lens.

  Further, the correction lens array 221 is disposed in the closest proximity to the doublet lens side constituted by the electromagnetic lenses 612 and 614 with respect to the molded aperture array substrate 603. The correction lens array 221 is configured by, for example, a three-stage electrode substrate, as shown in FIG. 7 (or FIG. 10) and FIG. 8, like the correction lens array 220.

  The control system circuit 560 includes a control computer 510, a memory 512, a lens control circuit 520, a correction lens control circuit 522, 524, a deflection control circuit 530, a deflection control circuit 532, a DAC amplifier 536, and a storage device 540 such as a magnetic disk device. Have. The control computer 510, the memory 512, the lens control circuit 520, the correction lens control circuits 522 and 524, the deflection control circuit 530, the deflection control circuit 532, and the storage device 540 are connected to one another via a bus (not shown). A DAC amplifier 536 is connected to the deflection control circuit 532. Drawing data in which a graphic pattern is defined is input from the outside of the drawing apparatus 100 and stored in the storage device 540 (storage unit). The lens control circuit 520, the correction lens control circuits 522 and 524, and the deflection control circuits 530 and 532 are controlled by the control computer 110.

The electromagnetic lenses 612 and 614 are connected to and controlled by the lens control circuit 420. The correction lens array 220 is connected to the correction lens control circuit 522 and controlled. The correction lens array 221 is connected to and controlled by the correction lens control circuit 524. The blanking aperture array mechanism 604 is connected to and controlled by the deflection control circuit 530. The deflector 608 is connected to the deflection control circuit 532 via the DAC amplifier 536 and controlled.
The lens system composed of the electromagnetic lenses 612 and 614 and / or the correction lens arrays 220 and 221 functions to form an image of the opening on the pre-formed aperture array substrate 624 on the corresponding opening of the formed aperture array substrate 503 at the same magnification. Have.

  Here, FIG. 18 illustrates a configuration necessary for explaining the third embodiment. The drawing apparatus 500 may normally have other necessary configurations.

  Similarly to the case shown in FIG. 2, the molded aperture array substrate 603 has predetermined holes (first openings) of vertical (y direction) m rows × horizontal (x direction) n rows (m, n ≧ 2). It is formed in a matrix with an arrangement pitch of. For example, 512 * 512 rows of holes 22 are formed.

  In addition, the pre-molded aperture array substrate 624 is configured in the same manner as the molded aperture array substrate 603. A plurality of holes (second openings) formed in the pre-molded aperture array substrate 624 are formed to have the same positional relationship as a plurality of corresponding holes formed in the molded aperture array substrate 603. However, the plurality of holes formed in the pre-molded aperture array substrate 624 are formed in a slightly larger size than the plurality of holes formed in the molded aperture array substrate 603. Thereby, the shape of the multi-beam 21 is determined by the shaping aperture array substrate 603. However, the present invention is not limited to this. The plurality of holes formed in the molded aperture array member 603 are formed to be slightly larger in size than the plurality of holes formed in the pre-molded aperture array member 624, and the plurality of holes formed in the pre-molded aperture array member 624 are The shape of the multi-beam 21 may be determined.

  In the blanking aperture array mechanism 604 in the first embodiment, a semiconductor substrate made of silicon or the like is disposed on a support base (not shown). The central portion of the semiconductor substrate is thinned from the back side, for example, and processed into a membrane region (first region) having a thin film thickness h. The periphery surrounding the membrane region is an outer peripheral region (second region) having a thick film thickness H. The semiconductor substrate is held on a support base on the back surface of the outer peripheral region. The central part of the support base is open, and the position of the membrane region is located in the open area of the support base.

  In the membrane region, passage holes (openings) for the passage of the respective multi-beams are opened at positions corresponding to the respective holes 22 of the shaped aperture array substrate 6. Then, a set of blanking deflection control electrodes and counter electrodes (blankers: blanking deflectors) are respectively disposed across the passage holes. Further, a control circuit (logic circuit) that applies a deflection voltage to the control electrode for each through hole is disposed in the vicinity of each through hole. The counter electrode for each beam is grounded.

  Corresponding electron beams of the multi-beams passing through the respective through holes are deflected independently by the voltage between the paired control electrode and the counter electrode. Blanking is controlled by such deflection.

  Next, the operation of the drawing mechanism 650 in the drawing apparatus 500 will be described. The electron beam 600 emitted from the electron gun 601 (emission unit) illuminates the entire pre-formed aperture array substrate 624 (first formed aperture array member) almost vertically by the illumination lens 602. A plurality of rectangular holes (first openings) are formed in the pre-molded aperture array substrate 624, and the electron beam 600 illuminates a region including all the plurality of holes. Each part of the electron beam 600 irradiated to the positions of the plurality of holes passes through the plurality of holes of the pre-molded aperture array substrate 624, for example, so that a plurality of rectangular electron beams (provisional multi-beams) are formed. 21 is formed. The temporary multi-beam 21 is focused by the electromagnetic lens 612 and, for example, scattered electrons (charged particles) that are off the focusing point are allowed to pass by the limiting aperture member 616 (first limiting aperture member) disposed at the focusing position. Limited. Thereby, the scattered electrons are shielded by the pre-molded aperture array substrate 624. Therefore, it is possible to prevent the scattered electrons from entering the downstream side. Then, the provisional multi-beam 21 from which scattered electrons have been cut by the limiting aperture substrate 616 is projected almost vertically onto the shaped aperture array substrate 603 by the electromagnetic lens 614.

  A plurality of rectangular holes (second openings) are formed in the molded aperture array substrate 603 (second molded aperture array member), and a plurality of electron beams (temporary multi-beams) projected by the electromagnetic lens 614 are formed. 21 passes through the corresponding holes of the plurality of holes (second openings) of the shaped aperture array substrate 603, thereby forming a plurality of rectangular electron beams (multi-beams) 20 having a desired size, for example. Molded. In other words, at least a part of the corresponding beam of the provisional multi-beam 21 passes through the plurality of holes of the shaping aperture array substrate 603 (second shaping aperture array member).

  Here, the number of imaging points of the multi-beam 20 can be reduced by determining the beam shape not by the upstream pre-formed aperture array substrate 624 but by the downstream shaped aperture array substrate 603. Therefore, the optical system can be prevented from becoming complicated. In the case of determining the beam shape on the pre-formed aperture array substrate 624 side, each beam passes through the formed aperture array substrate 603 in the downstream formed aperture array substrate 603, so that the beam passes through the formed aperture array substrate 603. There is an advantage that generation of scattered electrons at the time can be suppressed.

  Here, in the optical system using the doublet lens shown in FIG. 18, the correction lens array 220 individually corrects the beam trajectory for the temporary multi-beam 21 formed by the pre-molded aperture array substrate 624. Distortion correction and astigmatism correction can be performed. Here, it is possible to act on the concave lens by shifting the aperture center for each beam so that the shift amount gradually increases from the center of the multi-beam 21 toward the outside. The spherical aberration of crossover imaging can be reduced. The optimum value can be set by adjusting the shift amount of the aperture center for distortion correction and the shift amount of the aperture center for spherical aberration correction by simulation or the like. In the second embodiment, the shift amount of the opening center of the plurality of openings 12 of the middle electrode substrate 218 and the shape of the opening 12 are individually adjusted, so that, for example, a lattice lens that acts on a concave lens is not configured. Also, each beam can be corrected individually. Therefore, spherical aberration can be corrected in addition to distortion correction and astigmatism correction.

  The electromagnetic lenses 612 and 614 are excited by the lens control circuit 520 so that the magnetic fields are opposite and have the same magnitude. As a result, the multi-beam 21 that has passed through the electromagnetic lens 612 can be prevented from rotating when passing through the electromagnetic lens 614. Further, by constructing an antisymmetric doublet lens having a magnification of 1 in this way, distortion can be reduced. Since the magnification is 1, ideally, the limiting aperture member 616 is disposed at an exactly middle position between the electromagnetic lens 612 and the electromagnetic lens 614.

  Then, the distortion correction caused by the optical system after passing through the shaped aperture array substrate 603 is individually corrected by the correction lens array 221 with respect to the temporary multi-beam 21 incident on the shaped aperture array substrate 603. And astigmatism correction. As in the case of the correction lens array 220, the aperture center for each beam can be shifted so as to gradually increase the shift amount from the center of the multi-beam 21 toward the outside, thereby allowing the lens to act on the concave lens. The spherical aberration of the crossover imaging by 614 can be reduced. The optimum value can be set by adjusting the shift amount of the aperture center for distortion correction and the shift amount of the aperture center for spherical aberration correction by simulation or the like. Therefore, the trajectory of each beam can be individually corrected without configuring a grating lens that acts on the concave lens. Further, since the distortion amount by the electromagnetic lenses 612 and 614 constituting the doublet lens can be reduced, the shift amount of the opening center of the plurality of openings 12 of the middle electrode substrate 218 of the correction lens array 221 can be reduced correspondingly, and a new Occurrence of aberration can be suppressed.

  What are the shift amounts of the opening centers of the plurality of openings 12 of the correction lens array 220 and the shape of the openings 12, and the shift amounts of the opening centers of the plurality of openings 12 of the correction lens array 221 and the shapes of the openings 12. It may be adjusted separately by performing a simulation or the like.

  The multi-beams 20 that have passed through the shaped aperture array substrate 603 pass through blankers (first deflectors: individual blanking mechanisms) corresponding to blanking aperture array mechanisms 604 (other examples of the second aperture array member), respectively. pass. Each of these blankers deflects the electron beam 20 that individually passes (performs blanking deflection).

  The multi-beam 20 that has passed through the blanking aperture array mechanism 604 is focused by a reduction lens 605 (electromagnetic lens). In other words, the reduction lens 605 focuses the multi-beam 20 that has passed through the shaping aperture array substrate 603. At that time, the size of the multi-beam 20 image is reduced by the reduction lens 605. The multi-beam 20 refracted in the focusing direction by the reduction lens 605 (electromagnetic lens) travels toward a central hole formed in the limiting aperture member 606. The limiting aperture member 606 (second limiting aperture member) is disposed at the focal point position of the multi-beam 20 focused by the reduction lens 605 and limits the passage of the electron beam deviating from the focal point of the multi-beam 20. Here, the position of the electron beam 310 deflected by the blanker of the blanking aperture array mechanism 604 deviates from the central hole of the limiting aperture member 606 and is blocked by the limiting aperture member 606. On the other hand, the electron beam 20 that has not been deflected by the blanker of the blanking aperture array mechanism 604 passes through the central hole of the limiting aperture member 606. Beam ON / OFF is controlled by blanking control. In this way, the limiting aperture substrate 606 blocks each beam deflected so as to be in a beam OFF state. For each beam, one shot beam is formed by the beam that has passed through the limiting aperture substrate 606 formed from when the beam is turned on to when the beam is turned off. The multi-beam 20 that has passed through the limiting aperture substrate 606 is focused on the surface of the sample 501 by the objective lens 607 and becomes a pattern image having a desired reduction ratio, and each beam that has passed through the limiting aperture substrate 606 by the deflector 608. The entire multi-beam 20 is deflected all at once in the same direction, and is irradiated to each irradiation position on the sample 501 of each beam. In other words, the sample 101 placed on the continuously movable XY stage 505 is irradiated with at least a part of the beam group of the multi-beam 20 that has passed through the doublet lens. For example, when the XY stage 505 is continuously moving, the deflector 608 controls the beam irradiation position so as to follow (track) the movement of the XY stage 505. The position of the XY stage 505 is measured by irradiating a laser from a stage position detector (not shown) toward a mirror (not shown) on the XY stage 505 and using the reflected light. The multi-beams 20 irradiated at a time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes of the shaping aperture array substrate 603 by the desired reduction ratio. The drawing apparatus 500 irradiates each beam one pixel at a time along the drawing sequence by moving the beam deflection position by the deflector 608 while following the movement of the XY stage 505 during each tracking operation. The drawing operation is performed. When drawing a desired pattern, a beam required according to the pattern is controlled to be turned on by blanking control.

  As described above, according to the third embodiment, scattered electrons generated in the vicinity of the opening of the pre-molded aperture array substrate 624 can be shielded by the limiting aperture 616 by arranging the doublet lens. Further, by combining with the limiting aperture substrate 606 provided downstream, there is an advantage that the contrast can be further improved as compared with the case where there is no limiting aperture substrate 616 and only the limiting aperture substrate 606 blocks the scattered electrons.

  Furthermore, by arranging the correction lens array 220, it is possible to reduce the spherical aberration caused by the electronic lens 612 while maintaining the state in which the distortion of the multi-beam 21 is reduced by the electronic lens 612 constituting the doublet lens. As a result, the crossover diameter of the multi-beam 21 on the surface of the limiting aperture member 616 spread by the spherical aberration generated by the electron lens 612 can be reduced. Similarly, by arranging the correction lens array 221, the spherical aberration generated by the electronic lens 614 can be reduced while maintaining the state where the distortion of the multi-beam 21 is reduced by the electronic lens 614 constituting the doublet lens. As a result, the crossover diameter of the multi-beam 20 on the surface of the limiting aperture member 606 spread by the spherical aberration generated by the electron lens 614 can be reduced.

  In the above description, a series of “˜circuit” 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. Further, a common processing circuit (the same processing circuit) may be used for each “˜circuit”. Alternatively, different processing circuits (separate processing circuits) may be used. A program for executing a processor or the like may be recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (read only memory). For example, the position circuit 107, the comparison circuit 108, the reference image creation circuit 112, and the like may be configured by at least one processing circuit described above.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the configuration of the multi-beam irradiation mechanism described in Embodiment 1 can be applied not only to the inspection apparatus 100 but also to a drawing apparatus or the like. Similarly, the configuration of the multi-beam irradiation mechanism described in Embodiment 2 can be applied not only to the drawing apparatus 500 but also to an inspection apparatus or the like. Further, the above-described distortion correction, astigmatism correction, and spherical aberration correction are not limited to the case where the respective aberrations are completely reduced to zero, and it is only necessary that the respective aberrations can be made smaller than when the correction lens array is not used.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used.

  In addition, all multi-charged particle beam irradiation apparatuses and multi-charged particle beam irradiation methods that include 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.

DESCRIPTION OF SYMBOLS 10 Irradiation position 11, 12, 13 Aperture 20, 21 Multi beam 22 Hole 28 Pixel 29 Sub irradiation area 33 Mask die 34 Irradiation area 36 Pixel 100 Inspection apparatus 101 Substrate 102 Electron beam column 103 Inspection room 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 122 Laser length measurement system 123 Chip pattern memory 124 Lens control circuit 126 Blanking control circuit 128 Deflection control circuit 130 Correction lens control Circuit 132 Degraded pixel search circuit 142 Stage drive mechanism 144, 146 DAC amplifier 150 Image acquisition mechanism 160 Control system circuit 200 Electron beam 201 Electron gun 202 Illumination lens 203 Molding circuit Aperture array substrate 205 Reduction lens 206 Restriction aperture substrate 207 Objective lens 208 Main deflector 209 Sub deflector 212 Batch blanking deflector 214 Beam separator 216 Mirror 217 Upper electrode substrate 218 Middle electrode substrate 219 Lower electrode substrate 220, 221 Correction lens array 222 Multi-detector 224, 226 Projection lens 228 Deflector 300 Multi-secondary electron beams 317, 318, 319, 320, 321 Electrode substrate 330 Inspection area 332 Chip 500 Drawing device 501 Sample 502 Electron barrel 503 Drawing chamber 505 XY stage 510 Control Computer 512 Memory 520 Lens control circuit 522, 524 Correction lens control circuit 530 Deflection control circuit 532 Deflection control circuit 536 DAC amplifier 540 Storage device 550 Drawing mechanism 560 Control system Path 601 Electron gun 602 Illumination lens 603 Molding aperture array substrate 604 Blanking aperture array mechanism 605 Reduction lens 606 Limiting aperture member 607 Objective lens 608 Deflector 612, 614 Electromagnetic lens 616 Limiting aperture member 624 Pre-molding aperture array substrate 700 Drawing device 702 Electron beam column 703 Drawing chamber 750 Drawing mechanism 760 Control system circuit

Claims (5)

A stage on which a sample is placed;
A plurality of first openings formed at positions through which the multi-charged particle beam passes, and an upper electrode substrate to which a first potential is applied;
Including at least one second opening centered at a position shifted from the center of the corresponding first opening, which is disposed downstream of the upper electrode substrate with respect to the traveling direction of the multi-charged particle beam; A plurality of second openings corresponding to the plurality of first openings, and a middle electrode substrate to which a second potential is applied;
A plurality of third openings are formed on the downstream side of the middle electrode substrate with respect to the traveling direction of the multi-charged particle beam, and a plurality of third openings are formed at positions similar to the plurality of first openings. A lower electrode substrate to which a potential is applied;
A charged particle beam optical system for irradiating the sample with the multi-charged particle beam that has passed through the upper electrode substrate, the middle electrode substrate, and the lower electrode substrate;
A multi-charged particle beam irradiation apparatus comprising:   The shift amount of the center of the at least one second opening is set to an amount for correcting a shift amount from a design position of a corresponding beam irradiated on the sample surface. Multi charged particle beam irradiation device.   The multi-charged particle beam irradiation apparatus according to claim 1, wherein the at least one second opening is formed in an elliptical shape.   The multi-charged particle beam irradiation apparatus according to claim 1, wherein the at least one second opening is formed in a high-order rotationally symmetric shape. Measuring the amount of deviation from the design position of each beam when a sample is irradiated with a multi-charged particle beam using a charged particle beam optical system;
An upper electrode substrate in which a plurality of first openings are formed at a position through which the multi-charged particle beam passes; and an upper electrode substrate disposed downstream of the upper electrode substrate with respect to a traveling direction of the multi-charged particle beam, The plurality of first apertures including at least one second aperture centered at a position shifted from the center of the corresponding first aperture so as to individually correct the shift amount for each beam of charged particle beams. A middle electrode substrate in which a plurality of second openings corresponding to the openings are formed; and a plurality of first openings arranged on the downstream side of the middle electrode substrate with respect to the traveling direction of the multi-charged particle beam. A step of manufacturing a lens array having a lower electrode substrate in which a plurality of third openings are formed at the same position as the portion;
Arranging the lens array in the charged particle beam optical system and irradiating the sample with the multi-charged particle beam;
A multi-charged particle beam irradiation method comprising:

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