Beam array correction coefficient calculation method for multi-charged particle beam and multi-charged particle beam drawing method

Abstract

To calculate a correction coefficient of a beam array shape of multi-beams.SOLUTION: In a beam array correction coefficient calculation method according to an embodiment, at least one of a step of writing a first evaluation pattern by a first scan in which a beam is irradiated on each rectangular region including a plurality of pixels obtained by dividing a plurality of rectangular regions obtained by dividing a stripe in which a writing region of a substrate is divided in a y direction into the y direction and an x direction which is a direction perpendicular to the y direction into a mesh shape with a predetermined size, and a step of drawing a second evaluation pattern by a second scan of irradiating a beam in units of pixel rows in the y direction is executed. A position measurement corresponding to at least one of the drawn first evaluation pattern and the second evaluation pattern is performed, and a correction coefficient of distortion of a beam array shape on a substrate formed by the beam array is calculated using a result of the position measurement.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for calculating beam array correction coefficients for multiple charged particle beams and a method for writing with multiple charged particle beams. [Background technology]

[0002] As LSIs become more highly integrated, the circuit line width of semiconductor devices becomes ever finer. Electron beam lithography, which offers excellent resolution, is used to create exposure masks (also called reticles when used in steppers and scanners) for forming circuit patterns on these semiconductor devices.

[0003] For example, there is a lithography system that uses multiple beams. Compared to lithography using a single electron beam, using multiple beams allows for the irradiation of many beams at once, thereby significantly improving throughput. In a multi-beam lithography system, for example, an electron beam emitted from an electron gun is passed through a shaping aperture array substrate with multiple openings to form a multi-beam containing multiple individual beams. The multi-beam is reduced in size by an optical system, deflected by a deflector, and irradiated onto the desired position on the sample.

[0004] A multi-beam lithography system irradiates multiple individual beams at once, and connects the beams formed after passing through the same or different apertures in a shaping aperture array substrate to draw a pattern of the desired shape. The shape of the entire beam array irradiated onto the substrate (hereinafter sometimes referred to as the "beam array shape") affects the joining accuracy of the drawn figure, so the beam array shape is adjusted using an electron optical system.

[0005] Conventionally, an evaluation pattern is written on a substrate, and distortion of the beam array shape is analyzed using the writing results. For example, as shown in Figure 3, a writing area 50 on a substrate 40 is divided in the y direction into multiple rectangular stripe areas 52 with a predetermined width (e.g., the size of the beam array), and the XY stage on which the substrate 40 is placed is moved and adjusted so that an irradiation area 54 that can be irradiated with one multi-beam irradiation is positioned at the left end of the first stripe area 52, and then writing begins.

[0006] When writing the first stripe region 52, the XY stage is moved in the -x direction, thereby relatively writing in the +x direction. In the second stripe region 52, writing is performed in the -x direction. In the third stripe region 52, writing is performed in the +x direction, and in the fourth stripe region 52, writing is performed in the -x direction. Writing is performed in order from the first stripe region 52 to the last stripe region 52 until the entire writing region 50 is written.

[0007] When there is no distortion in the beam array shape as shown in FIG. 14(a), the joining precision of the stripe region 52A in which the evaluation pattern is written is high as shown in FIG. 14(b).

[0008] Distortion of the beam array shape includes expansion / contraction and rotation. Expansion / contraction consists of XX distortion, which indicates the amount of deviation in the X direction depending on the designed X position of each beam, as shown in Figure 15(a), and YY distortion, which indicates the amount of deviation in the Y direction depending on the designed Y position of each beam, as shown in Figure 16(a). In the figure, the dashed line indicates the designed position, and the arrow indicates the amount of deviation. XX distortion corresponds to expansion / contraction in the x direction of the beam array, as shown in Figure 15(b). YY distortion corresponds to expansion / contraction in the y direction of the beam array, as shown in Figure 16(b).

[0009] The rotation consists of XY distortion, which indicates the amount of deviation in the X direction depending on the designed Y position of each beam, as shown in Fig. 17(a), and YX distortion, which indicates the amount of deviation in the Y direction depending on the designed X position of each beam, as shown in Fig. 18(a). The XY distortion and YX distortion correspond to the rotation of the beam array as shown in Fig. 17(b) and Fig. 18(b), respectively.

[0010] When the beam array shape has YY distortion (expansion / contraction in the y direction), a deviation (e.g., a gap) occurs in the y direction in the stripe region 52B where the evaluation pattern is written, as shown in Fig. 19(a). When the beam array shape has XY distortion (rotation), a deviation in the x direction occurs in the stripe region 52C where the evaluation pattern is written, as shown in Fig. 19(b).

[0011] In this way, since the deviation caused by the YY distortion or XY distortion appears in the drawing result, a correction coefficient (first-order coefficient) can be calculated and adjusted in the electron optical system.

[0012] However, since the misalignment caused by XX distortion (expansion and contraction in the x-direction) and YX distortion (rotation) is difficult to see in the drawing results, the correction coefficient (first-order coefficient) cannot be calculated, which hinders the improvement of drawing accuracy. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-007379 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-103571 [Patent Document 3] Japanese Patent Application Publication No. 2017-220615 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been made in consideration of the above-described conventional situation, and has an object to provide a method for calculating a correction coefficient for a beam array shape of a multi-charged particle beam, and a multi-charged particle beam writing method for correcting the beam array shape using the calculated correction coefficient to write a pattern with high accuracy. [Means for solving the problem]

[0015] A method for calculating a beam array correction coefficient for a multi-charged particle beam according to one aspect of the present invention includes: irradiating a substrate placed on a stage with a multibeam using a beam array composed of a plurality of individual beams of charged particles, while performing a tracking operation so that the deflection position of the multibeam follows movement of the stage; and during the tracking operation, performing at least one of the following steps: drawing a first evaluation pattern by a first scan in which the beam is irradiated with the individual beams on each of a plurality of rectangular regions, each of which includes a plurality of pixels obtained by dividing a drawing area of ​​the substrate into stripes in a y direction, the stripes being further divided in the y direction and in an x ​​direction perpendicular to the y direction, into a mesh-like shape of a predetermined size; and drawing a second evaluation pattern by a second scan in which the beam is irradiated with the beam on each of a plurality of pixel columns in the y direction; performing position measurement corresponding to at least one of the drawn first evaluation pattern and the second evaluation pattern; and calculating a correction coefficient for distortion of the beam array shape on the substrate formed by the beam array using the results of the position measurement.

[0016] A multi-charged particle beam writing method according to one aspect of the present invention writes a pattern using multiple beams in a beam array shape corrected based on the correction coefficients calculated by the beam array correction coefficient calculation method. [Effects of the Invention]

[0017] According to the present invention, it is possible to calculate a correction coefficient for the beam array shape and improve the pattern writing accuracy. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of a drawing device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a shaped aperture array substrate. [Figure 3] FIG. 10 is a diagram illustrating an example of a drawing operation. [Figure 4] 10A and 10B are diagrams illustrating examples of multi-beam irradiation areas and pixels to be drawn. [Figure 5] 10(a) to 10(d) are diagrams illustrating an example of a drawing operation. [Figure 6] 10(a) to 10(d) are diagrams illustrating an example of a drawing operation. [Figure 7] 10 is a flowchart illustrating a method for calculating correction coefficients for a multi-beam beam array shape according to the embodiment. [Figure 8] 10(a) and 10(b) are diagrams showing the shot order. [Figure 9] 10(a) to 10(d) are diagrams showing examples of displacement amount maps of drawn evaluation patterns. [Figure 10] 10 is a graph showing the relationship between the designed x position and the amount of misalignment in the x direction. [Figure 11] 10 is a graph showing the relationship between the designed x position and the amount of misalignment in the y direction. [Figure 12] FIG. 10 is a diagram showing a symmetric shot order of an X-scan. [Figure 13] FIG. 10 is a diagram showing a symmetric shot order of a Y scan. [Figure 14] 1A is a diagram showing an ideal beam array shape, and FIG. 1B is a diagram showing a stripe region in which a pattern is written. [Figure 15] 10(a) is a diagram showing XX distortion, and FIG. 10(b) is a diagram showing expansion and contraction of the beam array shape in the x direction. [Figure 16] 10A is a diagram showing YY distortion, and FIG. 10B is a diagram showing expansion and contraction of the beam array shape in the y direction. [Figure 17] (a) is a diagram showing XY distortion, and (b) is a diagram showing rotation of the beam array shape. [Figure 18] FIG. 10(a) is a diagram showing YX distortion, and FIG. 10(b) is a diagram showing rotation of the beam array shape. [Figure 19] 10(a) and 10(b) are diagrams showing a state in which a shift occurs in a stripe region where a pattern is written. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and an ion beam or the like may also be used.

[0020] 1 is a schematic diagram of a drawing apparatus according to this embodiment. The drawing apparatus includes a control unit 100, a storage unit 102, and a drawing unit 200. The drawing apparatus is an example of a multi-charged particle beam drawing apparatus. The drawing unit 200 includes an electron optical column 20 and a drawing chamber 30. Inside the electron optical column 20, an electron gun 21, an illumination lens 22, a shaping aperture array substrate 23, a blanking aperture array substrate 24, a reduction lens 25, a limiting aperture member 26, an objective lens 27, and deflectors 28 and 29 are arranged. The reduction lens 25 and the objective lens 27 are both electromagnetic lenses, and the reduction lens 25 and the objective lens 27 form a reduction optical system.

[0021] An XY stage 32 is arranged in the patterning chamber 30. A substrate 40 to be patterned is placed on the XY stage 32. The substrate 40 is an exposure mask used when manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured, a mask blank coated with resist and on which nothing is yet to be patterned, or the like.

[0022] 2, apertures H are formed in a matrix of m rows and n columns (m, n≧2) at a predetermined arrangement pitch on the shaping aperture array substrate 23. Each aperture H is formed in the same rectangular or circular shape with the same dimensions.

[0023] An electron beam B emitted from an electron gun 21 (electron source) is illuminated almost perpendicularly onto the entire shaping aperture array substrate 23 by an illumination lens 22. As the electron beam B passes through a plurality of apertures H in the shaping aperture array substrate 23, a multi-beam MB consisting of individual beams arranged in m rows and n columns is formed.

[0024] The blanking aperture array substrate 24 has through holes formed in alignment with the positions of the apertures H of the shaping aperture array substrate 23. A pair of two electrodes (blankers: blanking deflectors) is disposed in each through hole. A control voltage is applied to one of the two electrodes, and the other is grounded. The individual beams passing through each through hole are deflected independently by the voltages applied to the pair of electrodes. Blanking control is performed by this deflection of the individual beams.

[0025] The multi-beams MB that have passed through the blanking aperture array substrate 24 are reduced in size by the reduction lens 25 and proceed toward the central opening formed in the limiting aperture member 26. The individual beams deflected by the blanker of the blanking aperture array substrate 24 move away from the central opening of the limiting aperture member 26 and are blocked by the limiting aperture member 26. On the other hand, the individual beams that have not been deflected by the blanker pass through the central opening of the limiting aperture member 26.

[0026] In this way, the limiting aperture member 26 blocks the individual beams deflected by the blanker to be in the beam-off state. Then, the beams formed from when the beams are turned on until when they are turned off and that pass through the limiting aperture member 26 form a beam for one shot.

[0027] The multi-beams MB that have passed through the limiting aperture member 26 are focused by the objective lens 27 to form a pattern image with a desired reduction ratio, and are deflected collectively by the deflectors 28 and 29 to be irradiated onto the substrate 40. For example, when the XY stage 32 is moving continuously, the deflector 28 (main deflector) controls the irradiation position of the beam so as to follow the movement of the XY stage 32.

[0028] The multiple beams MB irradiated at one time are ideally arranged at a pitch obtained by multiplying the above-mentioned desired reduction ratio by the arrangement pitch of the multiple apertures in the shaping aperture array substrate 23. The drawing device performs drawing operations using a raster scan method in which shot beams are continuously irradiated in order, and when drawing a desired pattern, the beams required for the pattern are turned on by blanking control.

[0029] For example, writing proceeds according to the following writing algorithm. As shown in Fig. 3, the writing region 50 on the substrate 40 is virtually divided into a plurality of rectangular stripe regions 52 with a predetermined width in the y direction. For example, the XY stage 32 is moved and adjusted so that an irradiation region 54 that can be irradiated with one multi-beam MB irradiation is positioned at the left end of the first stripe region 52, and writing begins. By moving the XY stage 32 in the -x direction, writing can proceed relatively in the +x direction.

[0030] After completing the drawing of the first stripe region 52, the stage position is moved in the -y direction to adjust the irradiation region to be positioned at the right end of the second stripe region 52, and drawing begins. Then, by moving the XY stage 32 in, for example, the +x direction, drawing is performed in the -x direction.

[0031] The writing time can be reduced by alternately changing the direction of writing, such as writing in the +x direction in the third stripe region 52 and writing in the -x direction in the fourth stripe region 52. However, writing is not limited to alternately changing the direction of writing, and writing in each stripe region 52 may proceed in the same direction.

[0032] FIG. 4 is a diagram showing an example of a multi-beam irradiation area and a pixel to be drawn. In FIG. 4, a stripe area 52 is divided into a plurality of mesh areas in a mesh shape, for example, based on the beam size of the individual beams. Each mesh area becomes a pixel 60 to be drawn (a unit irradiation area or a drawing position). The size of the pixel 60 to be drawn is not limited to the beam size of the individual beams, and may be any size.

[0033] 4 shows a case where the writing area 50 of the substrate 40 is divided, for example, in the y direction, into a plurality of stripe areas 52 each having a width substantially equal to the size of an irradiation area 54 (writing field) that can be irradiated with a single irradiation of the multi-beam MB. Note that the width of the stripe areas 52 is not limited to this.

[0034] The example of FIG. 4 shows the case of an 8×8 array of multi-beams. Within an irradiation area 54, a plurality of (64 in this example) pixels 44 (beam drawing positions) that can be irradiated with one shot of the multi-beam MB are shown. The pitch between adjacent pixels 44 is the pitch between individual beams of the multi-beam. In the example of FIG. 4, a square area surrounded by four adjacent pixels 44 and including one pixel 44 of the four pixels 44 constitutes one grid 46 (pitch cell). In the example of FIG. 4, each grid 46 is made up of 4×4 pixels.

[0035] 5(a) to 5(d) are diagrams illustrating an example of a writing operation in the stripe region 52. Figures 5(a) to 5(d) show an example of writing in the stripe region 52 using a 4x4 multi-beam in the x and y directions. In this example, the deflector 29 deflects the multi-beam to shift the irradiation position by one pixel in the x or y direction, and one irradiation region is exposed (written) by the entire multi-beam in 16 shots.

[0036] FIG. 5(a) shows the pixel irradiated by the first shot. Next, as shown in FIG. 5(b), the second, third, and fourth shots are performed sequentially, shifting the position by one pixel in the y direction. These four shots render one pixel column in the y direction (the first pixel column from the left in the grid). Next, as shown in FIG. 5(c), the fifth shot is performed by shifting the position by one pixel in the x direction from the first shot position. Next, the sixth, seventh, and eighth shots are performed sequentially, shifting the position by one pixel in the y direction. This results in the pixels in the second pixel column from the left being shot in order from the bottom up. By repeating the same operation, the ninth through sixteenth shots are performed sequentially, as shown in FIG. 5(d). The 16 shots render an area (grid 46) defined by the beam pitch. In this example, the 16 pixels in the grid are rendered with one individual beam.

[0037] Hereinafter, drawing within the grid in units of pixel columns in the y direction as shown in FIGS. 5(a) to 5(d) will be referred to as Y-scanning.

[0038] 6(a) to 6(d) are diagrams illustrating another example of the writing operation in the stripe region 52. FIG.

[0039] As shown in Figures 6(a) and 6(b), the first to fourth shots are performed in sequence, shifting the position by one pixel in the x direction. These four shots write one pixel row in the x direction (the first pixel row from the bottom in the grid). Next, as shown in Figure 6(c), the fifth shot is performed by shifting the position by one pixel in the y direction from the first shot position. Subsequently, the sixth, seventh, and eighth shots are performed in sequence, shifting the position by one pixel in the x direction. This results in the pixels in the second pixel row from the bottom being shot in order from left to right. Repeating the same operation, the ninth to sixteenth shots are performed in sequence, as shown in Figure 6(d). A single grid 46 can be written with 16 shots. In this example, the 16 pixels in the grid are written with one individual beam.

[0040] Hereinafter, drawing within a grid in units of pixel columns in the x direction as shown in FIGS. 6(a) to 6(d) will be referred to as X-scanning.

[0041] A desired pattern is drawn by irradiating a beam onto pixels where a figure pattern exists and not irradiating a beam onto pixels where no figure pattern exists.

[0042] The control unit 100 reads the drawing data from a storage device (not shown) and performs multiple stages of data conversion processing to generate shot data specific to the device. The shot data defines the dose and irradiation position coordinates of each shot.

[0043] The control unit 100 calculates the irradiation time t by dividing the irradiation amount of each shot by the current density. Then, when performing the corresponding shot, the control unit 100 applies a deflection voltage to the corresponding blanker on the blanking aperture array substrate 24 so that the blanker turns on the beam for the irradiation time t.

[0044] Furthermore, the control unit 100 applies deflection voltages to the deflectors 28 and 29 so that each beam is deflected to the position (coordinates) indicated by the shot data, thereby deflecting the multiple beams shot in that round collectively.

[0045] In multi-beam writing, the beam array shape affects the joining accuracy of the written image, so it is necessary to measure the distortion of the beam array shape and adjust the beam array shape using an electron optical system including the objective lens 27.

[0046] Distortion of the beam array shape includes expansion / contraction and rotation. Expansion / contraction consists of XX distortion, which indicates the amount of deviation in the X direction depending on the designed X position of each beam, and YY distortion, which indicates the amount of deviation in the Y direction depending on the designed Y position of each beam. Rotation consists of XY distortion, which indicates the amount of deviation in the X direction depending on the designed Y position of each beam, and YX distortion, which indicates the amount of deviation in the Y direction depending on the designed X position of each beam.

[0047] Conventionally, an evaluation pattern is written on a substrate, and distortion of the beam array shape is measured from the writing results. The writing results show misalignment caused by YY distortion and XY distortion (amount of misalignment dependent on the position in the y direction, which is perpendicular to the stage movement direction). However, misalignment caused by XX distortion and YX distortion (amount of misalignment dependent on the position in the x direction, which is the direction of stage movement) is difficult to detect in the writing results, making it difficult to adjust the beam array shape.

[0048] The present inventors have found that by writing an evaluation pattern with a Y scan shot order, deviations due to XX distortion appear in the writing results. Furthermore, the present inventors have found that by writing an evaluation pattern with an X scan shot order, deviations due to YX distortion appear in the writing results.

[0049] FIG. 7 is a flowchart illustrating a method for calculating correction coefficients for a multi-beam beam array shape according to this embodiment.

[0050] Using the shot sequence data in the storage unit 102, a first evaluation pattern is written on the substrate 40 by X-scanning (first scan) (step S1). The substrate 40 is, for example, a silicon wafer on which a light-shielding film such as chromium and a resist are laminated. The evaluation pattern is not particularly limited, but may be, for example, a line and space pattern. FIG. 8(a) shows an example of the shot sequence when X-scanning a grid consisting of 10 × 10 pixels.

[0051] A second evaluation pattern is written by Y-scanning (second scan) on the substrate 40 (step S2). Fig. 8(b) shows an example of the shot order when Y-scanning a grid made up of 10 x 10 pixels.

[0052] A development process is performed to form a resist pattern (Step S3). Subsequently, an etching process is performed using the resist pattern as a mask to process the light-shielding film (Step S4). After the etching process, the resist pattern is removed by ashing or the like.

[0053] The position of the evaluation pattern transferred onto the light-shielding film is measured using a scanning electron microscope (SEM) or the like (step S5).

[0054] The amount of misalignment, which is the difference between the position measurement result of the evaluation pattern and the design position, is calculated (step S6). The amount of misalignment in the x direction (ΔX) and the amount of misalignment in the y direction (ΔY) are calculated.

[0055] Figures 9(a) to 9(d) show examples of misalignment maps. Figure 9(a) shows the misalignment amount (ΔX) in the x direction of an evaluation pattern written by an X scan. Figure 9(b) shows the misalignment amount (ΔX) in the x direction of an evaluation pattern written by a Y scan. Figure 9(c) shows the misalignment amount (ΔY) in the y direction of an evaluation pattern written by an X scan. Figure 9(d) shows the misalignment amount (ΔY) in the y direction of an evaluation pattern written by a Y scan.

[0056] 9(a) to 9(d) show the y-position dependency of the amount of misalignment, and it is clear that the XY distortion and the YY distortion can be found.

[0057] As shown in FIG. 9(b), the drawing result in the Y scan shows the x-position dependency of the positional deviation amount in the x direction, and it is clear that the XX distortion can be obtained.

[0058] As shown in FIG. 9(c), the drawing result of the X scan shows the x-position dependency of the positional deviation amount in the y direction, and it is clear that the YX distortion can be obtained.

[0059] The shape of the multi-beam array can be approximated by the following linear equation:

[0060] (Equation 1) X=A0+A1x+A2y Y=B0+B1x+B2y

[0061] Figure 10 is a graph showing the relationship between the designed x position and the amount of misalignment in the x direction, which is determined from the drawing results of the Y scan. The slope of the arrow in Figure 10 (the slope of the approximate line) is calculated. This slope corresponds to the coefficient A1 in the above formula and indicates the XX distortion.

[0062] Figure 11 is a graph showing the relationship between the designed x position and the amount of misalignment in the y direction, as determined from the drawing results of the X scan. The slope of the arrow in Figure 11 (the slope of the approximate line) is calculated. This slope corresponds to the coefficient B1 in the above formula and indicates the YX distortion.

[0063] Note that the shaded areas in the graphs of Figures 10 and 11 are affected by overlap due to multiplicity, and are therefore not used in calculating the slope (coefficient).

[0064] Using the drawing results from the X scan or Y scan, a graph is created showing the relationship between the design y position and the amount of misalignment in the x and y directions, and coefficients A2 and B2 of the above formula that indicate XY distortion and YY distortion are calculated.

[0065] In this way, the first-order correction coefficients A1, A2, B1, and B2 are calculated (step S7).

[0066] Using the calculated correction coefficient, the excitation parameters (excitation current, applied voltage) of the electron optical system including the objective lens 27 are controlled to adjust the beam array shape (step S8).

[0067] As described above, according to this embodiment, the evaluation pattern is written by X scan and Y scan, so that positional deviations caused by each of XX distortion, YX distortion, YY distortion, and XY distortion appear in the result of writing the evaluation pattern, and correction coefficients (A1, A2, B1, B2) can be calculated and adjusted by the electron optical system.

[0068] Furthermore, by drawing a pattern with multiple beams in a beam array shape corrected using the calculated correction coefficient, it is possible to improve the drawing accuracy.

[0069] In the above embodiment, the X scan may be performed in any order as long as it performs drawing in units of pixel rows in the x direction. Furthermore, within a pixel row, the position may be shifted by one pixel in the +x direction or by one pixel in the -x direction.

[0070] Similarly, Y scan can be performed in any order as long as it performs drawing in units of pixel rows in the y direction. Furthermore, within a pixel row, the position can be shifted by one pixel in the +y direction or by one pixel in the -y direction.

[0071] For example, the shot order may be symmetric (line symmetric or point symmetric) within the grid. A line symmetric shot order means that, within one pixel row, individual beams are shot while being shifted by one pixel in a first direction, and then, within a pixel row at a symmetrical position with the center line of the grid as the axis of symmetry, individual beams are shot while being shifted by one pixel in the first direction. A line symmetric shot order means that, within one pixel row, individual beams are shot while being shifted by one pixel in the first direction, and then, within a pixel row at a symmetrical position with the center line of the grid as the axis of symmetry, individual beams are shot while being shifted by one pixel in a second direction opposite to the first direction.

[0072] Fig. 12 shows an example of a line-symmetric shot order and a point-symmetric shot order for an X scan, and Fig. 13 shows an example of a line-symmetric shot order and a point-symmetric shot order for a Y scan.

[0073] In the above embodiment, the method of drawing both the first evaluation pattern by X scanning and the second evaluation pattern by Y scanning has been described, but it is also possible to perform only one of them.

[0074] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0075] 20 Electron Optical Tube 21 Electron gun 22 Lighting lens 23 Shaped aperture array member 24 Blanking aperture array board 25. Reduction Lens 26 Limiting aperture member 27 Objective Lens 28, 29 Deflector 30 Drawing room 32 XY stage 40 boards 50 drawing area 52 Stripe Area 54 Irradiation area 100 control section 102 Storage section 200 Drawing section

Claims

1. a tracking operation is performed so that the deflection position of the multi-beam follows the movement of the stage while the substrate placed on the stage is irradiated with the multi-beam using a beam array composed of a plurality of individual beams of charged particles; During the tracking operation, at least one of a step of drawing a first evaluation pattern by a first scan in which the individual beams are irradiated with the beams on each of a plurality of rectangular regions, each of which includes a plurality of pixels obtained by dividing a drawing region of the substrate into stripes in a y direction and a plurality of rectangular regions, each of which is further divided in the y direction and an x ​​direction perpendicular to the y direction, into a mesh shape of a predetermined size, in units of pixel columns in the x direction, and a step of drawing a second evaluation pattern by a second scan in which the beams are irradiated with the beams on each of a plurality of rectangular regions, in units of pixel columns in the y direction, a beam array correction coefficient calculation method for a multi-charged particle beam, the method comprising: performing position measurement corresponding to at least one of the drawn first evaluation pattern and the drawn second evaluation pattern; and calculating a correction coefficient for distortion of the beam array shape on a substrate formed by the beam array using a result of the position measurement.

2. In the first scan, the irradiation position of each individual beam is shifted in the +x direction or the −x direction within the pixel row in the x direction to sequentially expose a plurality of pixels; 2. The beam array correction coefficient calculation method according to claim 1, wherein in the second scan, the irradiation positions of the individual beams are shifted in the +y direction or the −y direction within the pixel row in the y direction to sequentially expose a plurality of pixels.

3. The beam array correction coefficient calculation method according to claim 2 , wherein the shot order of the plurality of pixels in the rectangular region is line-symmetric or point-symmetric.

4. measuring a first positional deviation amount in the x direction according to the position in the x direction, a second positional deviation amount in the y direction according to the position in the x direction, a third positional deviation amount in the x direction according to the position in the y direction, and a fourth positional deviation amount in the y direction according to the position in the y direction from a result of positional measurement of at least one of the first evaluation pattern and the second evaluation pattern; calculating a correction coefficient corresponding to expansion or contraction of the beam array shape using the first positional deviation amount and the fourth positional deviation amount; The beam array correction coefficient calculation method according to claim 2 , further comprising: calculating a correction coefficient corresponding to a rotation of the beam array shape using the second positional deviation amount and the third positional deviation amount.

5. A multi-charged particle beam writing method for writing a pattern using multiple beams in a beam array shape corrected based on a correction coefficient calculated by the beam array correction coefficient calculation method according to any one of claims 1 to 4.

Images