Multi-beam drawing method and multi-beam drawing apparatus

Abstract

Provided are a multi-beam rendering method and apparatus that reduce system errors caused by emission order within a beam pitch unit. In a multi-beam drawing method, a drawing region of a substrate is divided into a plurality of stripe regions by a predetermined width in a direction perpendicular to a drawing traveling direction, and each stripe region is drawn with an intra-stripe weight N (N is an integer of 2 or more). M types (M is an integer of 2 or more) of segments, which define the emission order corresponding to a plurality of pixels to which each of a plurality of cells obtained by dividing the stripe region belongs, and which are different from each other, are generated, while deflecting a plurality of beams. A plurality of pixels in a cell are irradiated with an (m-1)-th section (m is an integer of 2 < = m < = M) by a first individual beam constituting a plurality of beams, and then the plurality of pixels in the cell are irradiated with an m-th section by a second individual beam different from the first individual beam, and irradiation with M types of sections in sequence is repeated. And all pixels in each unit are depicted by the weight N.

Description

[0001] Related Applications

[0002] This application claims the priority of Japanese Patent Application No. 2023-173682 (filing date: October 5, 2023) as a basic application. The present application incorporates all the contents of the basic application by reference. Technical Field

[0003] The present invention relates to a multi-beam drawing method and a multi-beam drawing device. Background Art

[0004] With the high integration of LSI, the circuit line width required for semiconductor devices is becoming finer every year. In order to form the desired circuit pattern for semiconductor devices, the following method is adopted: using a reduced projection exposure device, a high-precision original pattern formed on a quartz substrate as a light-shielding film or a reflective film is reduced and transferred to a wafer. In the process of making this high-precision original pattern, the so-called electron beam lithography technology is used to form a pattern by exposing the resist with an electron beam drawing device.

[0005] Compared with the case of drawing with a single electron beam, a drawing device using a multi-beam can irradiate more beams at a time, so the productivity can be greatly improved. In a multi-beam drawing device using a blanking aperture array as one mode of a multi-beam drawing device, for example, an electron beam emitted from an electron source is passed through a forming aperture array having a plurality of openings to form a multi-beam composed of a plurality of small beams (beamlets, individual beams). The multi-beam passes through the blankers described later in each corresponding blanking aperture array. The blanking aperture array has an electrode pair (blanker) for deflecting the beam individually, and an opening for the beam to pass is formed between the electrode pairs. By controlling the electrode pair to the same potential or to different potentials, the passing electron beam is blanked and deflected. The individual beam deflected by the blanker is shielded, and the individual beam that is not deflected is irradiated onto the substrate.

[0006] In the drawing process, for example, the drawing area of ​​the substrate is virtually divided into a plurality of stripe areas with a predetermined width in the y direction, and the beam array is adjusted so that it is located at the left end of the first stripe area, and the drawing is performed in the +X direction. After the drawing of the first stripe area is completed, the beam array is adjusted so that it is located at the right end of the second stripe area, and the drawing is performed in the -X direction.

[0007] As a high-precision drawing method, a multi-drawing method is known in which the necessary irradiation amount is divided into multiple drawings (exposures) in order to average the beam error. In the multi-drawing using multiple beams, the errors in the position and current of each beam are averaged, and the errors in the size and position of the drawing pattern are reduced. As a multi-drawing method, there are stripe multi-drawing in which stripes are staggered and overlapped, and intra-stripe multi-drawing in which multiple exposures are performed within one stripe.

[0008] In the stripe-in-multiple drawing, for example, the stripe area on the substrate is divided into a plurality of beam spacing units according to the beam spacing size of the multi-beam. One beam spacing unit is further divided into a plurality of pixels. Then, after the beams are emitted to all pixels in the emission order assigned to each pixel, the beams are further emitted to all pixels again in the same emission order. In this example, the same part is emitted twice, so it becomes a multi-drawing with a multiplicity of 2.

[0009] For example, consider the following situation: a beam spacing unit is composed of 10 pixels × 10 pixels = 100 pixels. While the worktable on which the substrate is mounted is continuously moved, the worktable is tracked, and the 10 pixels of the first row of the beam spacing unit are sequentially exposed. If 10 shots are performed and 10 pixels are exposed, the beam position is returned to the tracking start position (tracking reset). Repeat the exposure of 10 pixels and the tracking reset, exposing 100 pixels each time, to complete the first multiple exposure. The sequence of shots for 100 pixels is as follows: Fig. 22 The 100 pixels of the beam spacing unit are exposed again in the same order in the same emission sequence to complete the second multiple exposure.

[0010] However, if there is a systematic error in the emission order, each beam pitch unit is emitted in the same emission order in the first multiplexing and the second multiplexing, so there is a problem that the averaging effect of multiple drawing cannot be obtained. For example, if charging occurs in the column due to the tracking reset operation and the position of the beam is shifted, and this position shift decays between the exposure operations of 10 pixels in tracking, Fig.10 In the above example, each beam spacing unit is emitted in the same emission order in the first multiplexing and the second multiplexing, so the averaging effect brought by the multiple depiction cannot be obtained. Fig.11 As shown, a systematic error occurs in the emission position of each pixel, resulting in errors in the position and line width of the drawn pattern.

[0011] There is a known method of making it difficult for systematic errors to occur by dispersing the transmission sequence within the beam spacing unit in position. Fig.23The exposure positions in the beam spacing unit in one tracking shown above are not biased in the x-direction and the y-direction, and the dispersion of the emission position error distribution can be spatially dispersed. The emission order can be generated by a random number generator. However, even if this method is used, it is difficult to fully reduce the systematic error corresponding to the emission order because each beam spacing unit for simultaneous exposure with multiple beams is emitted in the same emission order. Summary of the invention

[0012] One aspect of the present invention provides a multi-beam mapping method and a multi-beam mapping device for reducing a systematic error caused by a transmission order within a beam pitch unit.

[0013] A multi-beam drawing method according to one embodiment of the present invention is a method for dividing a drawing area of ​​a substrate on a workbench of a beam array irradiated with a multi-beam into a plurality of stripe areas with a predetermined width in a direction perpendicular to a drawing advancing direction, and into a plurality of pixels as an irradiation unit area of ​​each individual beam constituting the multi-beam, and drawing is performed with a predetermined intra-strip multiplicity N for each stripe area, wherein N is an integer greater than or equal to 2, and the multi-beam drawing method comprises the following steps: generating M types of segments, the M types of segments defining emission orders corresponding to a plurality of pixels belonging to each of a plurality of units obtained by dividing the stripe area and being different from each other, wherein M is an integer greater than or equal to 2, while deflecting the multi-beam, irradiating a plurality of pixels in the unit using an m-1th segment by a first individual beam, and then irradiating a plurality of pixels in the unit using an mth segment by a second individual beam different from the first individual beam, wherein m is an integer of 2≤m≤M, and drawing all pixels in each unit with the multiplicity N by repeatedly irradiating using the M types of segments in sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a multi-charged particle beam mapping device according to an embodiment of the present invention.

[0015] Figure 2 is a top view of the formed aperture component.

[0016] Figure 3 This is a diagram for explaining an example of a drawing operation.

[0017] Figure 4 This is a diagram showing an example of a multi-beam irradiation area and rendering target pixels.

[0018] Figure 5 This is a diagram for explaining an example of a drawing operation.

[0019] Figure 6 This is a diagram for explaining an example of a drawing operation.

[0020] Figure 7 (a) to (c) are explanatory diagrams of multiple depictions within stripes.

[0021] Figure 8 (a) to (c) are explanatory diagrams of multiple depictions within stripes.

[0022] Fig. 9 (a) to (c) are explanatory diagrams of multiple depictions within stripes.

[0023] Fig.10 It is a diagram showing the deviation of the emission position.

[0024] Fig.11 : is a diagram showing an example of systematic error according to the transmission order.

[0025] Fig.12 It is a diagram showing an example of a beam array.

[0026] Fig.13 (a) to (d) are explanatory diagrams of the multiple drawing method within a stripe according to this embodiment.

[0027] Fig.14 (a) to (d) are explanatory diagrams of the multiple drawing method within a stripe according to this embodiment.

[0028] Fig.15 This is a diagram showing an example of a segment in which the transmission order and transmission position are defined.

[0029] Fig.16 (a) to (d) are diagrams illustrating the emission order within each pitch unit.

[0030] Fig.17 It is a diagram showing an example of a beam array.

[0031] Fig.18 This is a diagram showing an example of a segment in which the transmission order and transmission position are defined.

[0032] Fig.19 (a) to (c) are explanatory diagrams of the multiple drawing method within a stripe according to this embodiment.

[0033] Fig. 20 (a) to (c) are explanatory diagrams of the multiple drawing method within a stripe according to this embodiment.

[0034] Fig.21 This is a diagram showing an example of a segment in which the transmission order and transmission position are defined.

[0035] Fig. 22 It is a diagram illustrating the transmission order within a pitch unit.

[0036] Fig.23 It is a diagram illustrating the transmission order within a pitch unit. DETAILED DESCRIPTION

[0037] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, a configuration using an electron beam is described as an example of a beam. However, the beam is not limited to an electron beam, and may be another charged particle beam such as an ion beam.

[0038] Figure 1 2 is a schematic diagram of the drawing device of the embodiment. Figure 1 As shown, the drawing device 100 includes a drawing unit 100W and a control unit 100C. The drawing device 100 is an example of a multi-charged particle beam drawing device. The drawing unit 100W includes an electron lens barrel 102 and a drawing chamber 103. An electron source 201, an illumination lens 202, a forming aperture component 203, a blanking aperture array substrate 204, a reduction lens 205, a limiting aperture component 206, an objective lens 207, and deflectors 208 and 209, which constitute a multi-beam generating mechanism, are arranged in the electron lens barrel 102. As described later, the deflector 208 is used for stage tracking deflection, and the deflector 209 is used for positioning the multi-beams to the pixels. In addition, a deflector having the functions of the deflector 209 and the deflector 208 can also be provided, and the one deflector can be used to perform both the stage tracking deflection and the multi-beam positioning to the pixels.

[0039] An XY stage 105 is disposed in the drawing chamber 103. A substrate 101 to be drawn is disposed on the XY stage 105. The substrate 101 is, for example, a mask blank or a semiconductor substrate (silicon wafer).

[0040] A reflection mirror 210 for position measurement is arranged on the XY stage 105 .

[0041] The control unit 100C includes a control computer 110, a deflection control circuit 130, a table position detector 139, and a storage unit 140. Drawing data is input from the outside to the storage unit 140 and stored. In addition, the storage unit 140 stores information of a segment described later. The drawing data generally defines information of a plurality of graphic patterns used for drawing. Specifically, a graphic code, coordinates, size, etc. are defined for each graphic pattern.

[0042] The control computer 110 includes an area ratio calculation unit 111, an irradiation amount calculation unit 117, and a drawing control unit 118. Each unit of the control computer 110 may be composed of hardware such as an electric circuit, or software such as a program that executes its functions, or a combination of hardware and software.

[0043] The stage position detector 139 irradiates laser light and receives reflected light from the reflection mirror 210 , thereby detecting the position of the XY stage 105 using a laser interferometer method.

[0044] Figure 2 2 is a conceptual diagram showing the structure of the forming aperture component 203. Figure 2 As shown, the aperture forming member 203 is formed with m rows in the longitudinal direction (y direction) and n columns in the transverse direction (x direction) (m, n ≥ 2) at a predetermined arrangement pitch. Each opening 22 is formed by a rectangle of the same size and shape. Each opening 22 can also be a circle of the same outer diameter. Parts of the electron beam 200 pass through the plurality of openings 22, respectively, to form multiple beams 20a to 20e.

[0045] In the blanking aperture array substrate 204, through holes are formed to match the configuration positions of the openings 22 of the forming aperture component 203. A group of two electrodes (blankers) are respectively configured in pairs in each through hole. The electron beam passing through each through hole is independently controlled to a beam-on or beam-off state according to each beam by the voltage applied to the blanker. When the beam is on, the opposing electrodes of the blanker are controlled to the same potential, and the blanker does not deflect the beam. When the beam is off, the opposing electrodes of the blanker are controlled to different potentials from each other, and the blanker deflects the beam. In this way, a plurality of blankers blank and deflect the beams corresponding to each blanker in the multiple beams passing through the plurality of openings 22 of the forming aperture component 203.

[0046] The electron beam 200 emitted from the electron source 201 (emission unit) illuminates the entire aperture forming member 203 substantially vertically by the illumination lens 202. The electron beam 200 illuminates a region including all the openings 22. The electron beam 200 passes through the plurality of openings 22 of the aperture forming member 203, thereby forming a plurality of electron beams (multi-beams) 20a to 20e in, for example, a rectangular shape.

[0047] The multiple beams 20a to 20e pass through the blankers of the blanking aperture array substrate 204. The blankers deflect the electron beams that pass through individually. The multiple beams 20a to 20e that pass through the blanking aperture array substrate 204 are reduced by the reduction lens 205, and when all beams are turned on, they ideally pass through the same point on the limiting aperture component 206. The beam trajectory is adjusted by a correction coil (not shown) so that the point is located in the opening at the center of the limiting aperture component 206.

[0048] Here, the beam controlled to be in the beam-off state is deflected by the blanker of the blanking aperture array substrate 204, and the beam trajectory leads to the outside of the opening of the limiting aperture component 206, so it is shielded by the limiting aperture component 206. On the other hand, the beam controlled to be in the beam-on state is not deflected by the blanker, so it passes through the opening of the limiting aperture component 206. In this way, the on / off of the beam is controlled by the blanking control of the blanking aperture array substrate 204.

[0049] The limiting aperture member 206 shields each beam deflected by the plurality of blankers to a beam-off state. Then, multiple beams are formed in one emission using beams formed from beam-on to beam-off and passing through the limiting aperture member 206.

[0050] The multi-beams that have passed through the limiting aperture component 206 are focused by the objective lens 207 and projected onto the substrate 101 at a desired reduction ratio. The deflectors 208 and 209 can deflect the multi-beams as a whole. The deflection amounts of the deflectors 208 and 209 are independently controlled. The irradiation position of the multi-beams on the substrate 101 is controlled by the deflectors 208 and 209.

[0051] During the drawing, the XY table 105 is controlled to move continuously at a certain speed. At this time, the deflector 208 is controlled so that the irradiation position of the beam follows the movement of the XY table 105. The multiple beams irradiated simultaneously are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the multiple openings of the forming aperture component 203 by the above-mentioned desired reduction rate. During the drawing, the multiple beams perform a drawing operation of a raster scanning method that exposes all pixels defined on the substrate 101 through position control based on deflection. When the beam is located on a pixel that does not contain a pattern, the beam is controlled to be disconnected through blanking control.

[0052] Figure 3 2 is a conceptual diagram for explaining the drawing operation in this embodiment. Figure 3 As shown, the drawing area 30 on the substrate 101 is virtually divided into a plurality of stripe areas 32 with a predetermined width, for example, in the y direction (first direction), and the length direction (x direction or second direction) of the stripe area 32 orthogonal to the y direction becomes the drawing advancing direction. When drawing these stripe areas 32, the XY stage 105 is first moved and adjusted so that the irradiation area (beam array) 34 that can be irradiated by one multi-beam irradiation is located at the left end of the first stripe area 32, and the drawing is started.

[0053] When drawing the first stripe region 32, the XY stage 105 is continuously moved in the -x direction at a constant speed, thereby drawing the substrate 101 relatively in the +x direction. After the drawing of the first stripe region 32 is completed, the XY stage 105 stops. Next, the stage position is moved in the -y direction by the stripe width, and the beam array 34 is adjusted to be located at the right end of the second stripe region 32. Next, the XY stage 105 is continuously moved in the +x direction at a constant speed, thereby drawing the substrate 101 toward the -x direction.

[0054] The third stripe region 32 is drawn in the +x direction, and the fourth stripe region 32 is drawn in the −x direction. Although each stripe region 32 may be drawn in the same direction, in this case, an operation of returning the stage position is added after drawing, so the drawing time is increased.

[0055] Figure 4 FIG. 1 is a diagram showing an example of a multi-beam irradiation area and a pixel to be drawn. Figure 4 In the stripe region 32, for example, a plurality of control grids 27 are arranged in a grid pattern at a pitch corresponding to the beam size of the multi-beam on the surface of the substrate 101. For example, the arrangement pitch is preferably about 10 nm.

[0056] The plurality of control grids 27 form an ideal irradiation position (ideal position) where the positions of the multiple beams are not offset. The arrangement pitch of the control grids 27 is not limited to the same size as the beam size, but may be any size that can be controlled as the deflection position of the deflector 209. In addition, a plurality of pixels 36 are set that are virtually divided into a grid shape with the same size as the arrangement pitch of the control grids 27, centered around each control grid 27.

[0057] Each pixel 36 becomes an irradiation unit area of ​​each beam (individual beam) of the multi-beam. Figure 4 In the example of FIG. 1 , a case is shown where the drawing area of ​​the substrate 101 is divided into a plurality of stripe areas 32 in the y direction with the same width size as the size of the beam array 34 (drawing area) that can be irradiated by one multi-beam 20 irradiation. The size of the beam array 34 in the x direction is a value obtained by multiplying the beam pitch in the x direction of the multi-beam by the number of beams in the x direction. The size of the beam array 34 in the y direction is a value obtained by multiplying the beam pitch in the y direction of the multi-beam by the number of beams in the y direction.

[0058] exist Figure 4In the figure, an example of a multi-beam of 8×8 columns is shown. In addition, the multi-beam is not limited to 8×8 columns, and 512×512 columns or the like can be used appropriately. Moreover, in the beam array 34, a plurality of pixels 28 (beam drawing positions) that can be irradiated by a single multi-beam emission are represented as blackened pixels. In other words, the spacing between adjacent pixels 28 becomes the spacing between each beam of the designed multi-beam. Here, the area of ​​the beam spacing size is set as the spacing unit 29. In Figure 4 In the example of FIG. 4 , each pitch unit 29 is composed of 4×4 pixels.

[0059] When drawing each stripe area 32, in parallel with the continuous movement of the XY stage 105 in the x direction, the beam position is controlled by the deflectors 208 and 209 so that all pixels on the substrate 101 are exposed the same number of times. At this time, the deflector 208 performs deflection control of the beam position (stage tracking) so that the beam being exposed follows the continuous movement of the substrate 101. The deflector 209 controls the switching of the exposure pixels. When switching the exposure pixels, the deflector 209 deflects the beam array within the range of the pitch unit 29.

[0060] exist Figure 5 In FIG. 1 , an example is shown in which four multi-beams are arranged in the x direction at intervals of four times the beam size. Although there may be four or different rows of multi-beams in the y direction, each row of multi-beams depicts an area of ​​beam pitch width corresponding to the width of the sub-irradiation area 29, so it can also be considered that Figure 5 Represents a row of a multi-beam array having multiple rows and the pixels they should expose.

[0061] exist Figure 5 In the example of , the following repetitive process is shown, that is, while the stage continuously moves in the -x direction, each beam exposes one column consisting of 4 pixels in the y direction, and then the beam moves in the +x direction to expose another column. As described above, here, while each beam exposes one column of 4 pixels, the deflector 209 applies a deflection for switching the exposed pixels in the y direction in parallel with the stage tracking operation of the deflector 208, and the stage tracking operation is to perform continuous deflection following the movement of the stage so that the position of the beam array in the x direction on the substrate 101 does not change. The larger movement of the beam in the +x direction after exposing one column is performed by the tracking reset operation, which is an operation to stop the stage tracking and return the deflection amount of the deflector 208 to the deflection amount at the start of the stage tracking.

[0062] exist Figure 5In the example, the pixel groups are divided into regions of the beam pitch width, but when the beam moves to another column, the beam moves to a region of another pitch width. This movement is performed by controlling the amount of deflection applied by the deflector 209 in the x direction. That is, the deflector 208 performs tracking deflection, and the deflector 209 performs deflection within the pitch unit 29, thereby performing raster scanning. In addition, in Figure 5 In the exposure process shown, only a part of the pixels in the area of ​​the third pitch width from the left are exposed, but all the pixels in the area of ​​the right pitch width are exposed by further repeating the above process. That is, after the exposure starts, the three beam pitch areas become incompletely exposed, so in order to prevent the actual drawing area from entering this part, the drawing operation is started in advance from the area to the left of the drawing area.

[0063] In this example, during the tracking period, a plurality of pixels are sequentially exposed in the +y direction, but the present invention is not limited thereto. Figure 6 As shown, exposure can also be performed sequentially in the +x direction.

[0064] In multi-beam imaging, in order to average out errors in the position and current amount of each beam, it is preferable to perform multi-image imaging by dividing the necessary irradiation amount into a plurality of image formations (exposures).

[0065] A known method is "multiple intra-fringe drawing" in which a beam array is divided into a plurality of regions with a predetermined uniform width in the x direction (drawing direction) and the beams in each divided region draw the same portion while drawing one fringe region.

[0066] For example, when the emission sequence assigned to each pixel is repeated twice for the pixels in the beam spacing area, such as Figure 7 As shown in (a), the beam array 34 is divided into two regions (sub-beam arrays) of block region R1 and block region R2, and the pixels in the stripe 32 are depicted once each using the beam belonging to region R1 and the beam belonging to region R2. Figure 7 (b) Figure 7 As shown in (c) of FIG. 1 , the shaded area in the figure is irradiated with the beam of area R1 and then irradiated with the beam of area R2. Therefore, one area is drawn twice, so the multiplicity is 2.

[0067] For example, Figure 5 , Figure 6 In the example, the 4×4 pixels in the beam pitch area are exposed once by one of the four multi-beams a, b, c, and d, but the 4×4 pixels are exposed one by one by a and b in the right half of the multi-beams of 1 row of 4. Next, the 4×4 pixels are exposed one by one by c and d in the left half of the multi-beams. Figure 5 , 6In the embodiment, each of the four multi-beams a, b, c, d performs a depiction with a multiplicity of 1 by respectively exposing four of the 4×4 pixels in the beam spacing area. However, when the four multi-beams a, b, c, d are divided into two block areas, in other words, divided into multi-beams a, b and c, d to perform a depiction with a multiplicity of 2, each of the four multi-beams a, b, c, d exposes eight of the 4×4 pixels in the beam spacing area.

[0068] A specific example of a drawing method based on multiple drawing within a stripe is described. Figure 8 As shown in (a), the beam array 34 is divided into two block areas R1 and R2. One side of the beam array is set to 80 μm, and the width of the stripe area 32 is also set to 80 μm. One side of the spacing unit 29 that divides the stripe area with the beam spacing size of the multi-beam is set to 160 nm. The emission size (the size of a single beam) is set to 16 nm. The spacing unit is composed of 10 pixels × 10 pixels = 100 pixels.

[0069] exist Figure 8 In the present invention, the focus is on the pitch unit 29 as one of the pitch units, and how the 10×10 pixels in the pitch unit are exposed by the beam array 34 is described. A plurality of tracking start positions are set for the stripes 32. Figure 8 The vertical line indicates the position of the right end of the pitch unit where the beam at the right end of the beam array is located in the stripe 32 at the start of tracking. There is more than one pitch unit between the tracking start point and the next start point. Figure 8 In the example, multiple spacing units are included.

[0070] In this case, the inter-beam spacing dimension does not refer to the spacing dimension between beams rigidly arranged adjacent to each other, but refers to the spacing between multiple beams used for drawing. For example, in order to limit the total current amount, when a rigidly specified beam is used every other beam (otherwise it is OFF), the inter-beam spacing dimension becomes a spacing that is twice the rigidly specified spacing.

[0071] While the XY stage 105 is continuously moved and the stage tracking is performed, 10 pixels of the first row of the pitch unit are sequentially exposed using one beam of the block area R1. If 10 shots (shot 1 to shot 10) are performed, tracking reset is performed, in other words, the beam position in the deflection coordinate system is returned to the tracking start position. At this time, the beam position on the substrate 101 moves to the pitch unit to the right than during the tracking reset. In other words, on the substrate 101, the beam position moves in the +X direction and is positioned in another pitch unit. The multiple beams are deflected together by the deflector 208, so through the tracking reset, each beam of the multiple beams moves the same amount to the pitch unit on the right by the same amount.

[0072] like Figure 8 As shown in (b), the next stage tracking is started, and another beam in the block region R1 is used to sequentially expose 10 pixels in the second row of the pitch unit. After 10 shots, in other words, shots 11 to 20, tracking reset is performed.

[0073] In this way, the exposure and tracking reset of 10 pixels are repeated according to each stage tracking, so that Figure 8 As shown in (c), the 100 pixels of the pitch unit 29 of interest are exposed one by one using the multiple beams of the block area R1. That is, while the block area R1 passes through the pitch unit 29 of interest, the 100 pixels of the pitch unit 29 are exposed one by one, and the exposure of the multiplicity 1 (first multiplicity) of the multiple beams of the block area R1 is completed. The emission order of the 100 pixels is as follows: Fig. 22 Like that.

[0074] The drawing operation is continued, and the focused pitch unit 29 is exposed by the beam of the block region R2. After the exposure of the beam of the region R1 with multiplicity 1 is completed, the tracking reset is performed so that the beam of the region R2 is located at the focused pitch unit 29. Therefore, Fig. 9 As shown in (a), one beam of the block region R2 is used to sequentially expose 10 pixels of the first row of the pitch unit. After 10 shots, in other words, shots 101 to 110, tracking reset is performed. The second exposure (second path) of the 10 pixels of the first row is performed.

[0075] like Fig. 9 As shown in (b), the next stage tracking starts, and another beam of the block area R2 is used to sequentially expose 10 pixels of the second row of the pitch unit. After 10 shots, in other words, shots 111 to 120, tracking reset is performed.

[0076] While the stage is tracking, the exposure and tracking reset of 10 pixels are repeated. Fig. 9 As shown in (c), the 100 pixels of the pitch unit are exposed one by one by using the multiple beams of the block area R2. That is, while the block area R2 passes through the pitch unit 29 of interest, the 100 pixels of the pitch unit 29 are exposed one by one, and the exposure of the multiplicity 1 (second multiplicity) based on the multiple beams of the block area R2 is completed.

[0077] Through this drawing process, 100 pixels of the pitch unit are exposed twice each, and the multiplicity becomes 2.

[0078] exist Figure 8 (a)~ Figure 8 (c) Fig. 9 (a)~ Fig. 9 In the example shown in (c) of FIG. 1 , the pixels of the first row of a pitch unit are emitted from left to right, and then the pixels of the second row are emitted from left to right in a monotonous emission order. Fig.10 That is, when charging occurs in the column due to the tracking reset operation and the position of the beam is shifted, and this position shift decays between the exposure operations of 10 pixels in tracking, Fig.10 Such a biased distribution of emission positions.

[0079] In the above example, each pitch unit is transmitted in the same transmission order in the first multiple and the second multiple, so Fig.11 As shown, a systematic error occurs in the emission position of each pixel, and errors occur in the position and line width of the drawn pattern.

[0080] By making the transmission sequence within the beam spacing unit dispersed in position, it is possible to make it difficult for systematic errors to occur. Fig.23 The dispersed emission order shown can make the error distribution of the emission position dispersed in space. The dispersed emission order is that the exposure position within the beam spacing unit in one tracking is not biased in the x direction and the y direction. Hereinafter, this emission order is referred to as a random emission order. The random emission order can be generated by a random number generator. In multi-beam drawing, the positions of the multiple beams are controlled by the deflector 209, so each spacing unit exposed at the same time is emitted in the same emission order, and a systematic error corresponding to the emission order may occur, which hinders the improvement of drawing accuracy.

[0081] The inventors of the present invention have discovered that in the intra-stripe multiple drawing method, by assigning different emission orders to a plurality of pitch units within a stripe region, the systematic error caused by the emission order can be averaged, thereby improving the drawing accuracy.

[0082] use Figure 12 to Figure 14 An example of this depiction method is described below. Fig.12 As shown, a beam array composed of 8×1 individual beams (beamlets) is used to perform intra-fringe multiplexing with a multiplicity of 2. The pitch unit is composed of 2 pixels×2 pixels=4 pixels.

[0083] First, if Fig.13 As shown in (a), the beam array is moved in the y direction while the stage is tracked, and the two pixels on the left side of the pitch unit are emitted. Fig.13(a) shows a state where the individual beams a and b are radiated to two pixels on the left side of the pitch units P2 and P1. The number in the pixel indicates the number of radiated times of the pixel.

[0084] Perform tracking reset to align the beam drawing position with the lower right pixel of each pitch unit. Fig.13 As shown in (b), the beam array is moved in the y direction while the stage is being tracked, and the two pixels on the right side of the pitch unit are emitted.

[0085] Fig.13 (b) shows a state where the individual beams a and b are emitted to two pixels on the right side of the pitch units P4 and P3 and the individual beams c and d are emitted to two pixels on the right side of the pitch units P2 and P1.

[0086] Perform tracking reset to align the beam drawing position with the upper left pixel of each pitch unit. Fig.13 As shown in (c), the beam array is moved in the x direction while the stage is tracked, and the beam is emitted to the two pixels on the upper side of the pitch unit.

[0087] Fig.13 (c) shows the state where separate beams a and b emit to the two pixels on the upper side of spacing units P6 and P5, separate beams c and d emit to the two pixels on the upper side of spacing units P4 and P3, and separate beams A and B emit to the two pixels on the upper side of spacing units P2 and P1.

[0088] Perform tracking reset to align the beam drawing position with the lower left pixel of each pitch unit. Fig.13 As shown in (d), the beam array is moved in the x direction while the stage is tracked, and the beam is emitted to the two pixels on the lower side of the pitch unit.

[0089] Fig.13 (d) shows the state in which separate beams a and b emit to the two pixels at the bottom of spacing units P8 and P7, separate beams c and d emit to the two pixels at the bottom of spacing units P6 and P5, separate beams A and B emit to the two pixels at the bottom of spacing units P4 and P3, and separate beams C and D emit to the two pixels at the bottom of spacing units P2 and P1.

[0090] Thus, the four pixels of the pitch units P1 and P2 are exposed twice each.

[0091] Perform tracking reset to align the beam drawing position with the lower left pixel of each pitch unit. Fig.14 As shown in (a), the beam array is moved in the y direction while the stage is tracked, and the two pixels on the left side of the pitch unit are emitted.

[0092] Fig.14 (a) shows the state in which separate beams a and b emit to the two pixels on the left side of spacing units P10 and P9, separate beams c and d emit to the two pixels on the left side of spacing units P8 and P7, separate beams A and B emit to the two pixels on the left side of spacing units P6 and P5, and separate beams C and D emit to the two pixels on the left side of spacing units P4 and P3.

[0093] Thus, the four pixels of the pitch units P3 and P4 are exposed twice each.

[0094] Perform tracking reset to align the beam drawing position with the lower right pixel of each pitch unit. Fig.14 As shown in (b), the beam array is moved in the y direction while the stage is being tracked, and the two pixels on the right side of the pitch unit are emitted.

[0095] Fig.14 (b) shows the state in which separate beams a and b emit to the two pixels on the right side of spacing units P12 and P11, separate beams c and d emit to the two pixels on the right side of spacing units P10 and P9, separate beams A and B emit to the two pixels on the right side of spacing units P8 and P7, and separate beams C and D emit to the two pixels on the right side of spacing units P6 and P5.

[0096] Thus, the four pixels of the pitch units P5 and P6 are exposed twice each.

[0097] Perform tracking reset to align the beam drawing position with the upper left pixel of each pitch unit. Fig.14 As shown in (c), the beam array is moved in the x direction while the stage is tracked, and the beam is emitted to the two pixels on the upper side of the pitch unit.

[0098] Fig.14 (c) shows the state in which separate beams a and b are emitting to the two pixels on the upper side of spacing units P14 and P13, separate beams c and d are emitting to the two pixels on the upper side of spacing units P12 and P11, separate beams A and B are emitting to the two pixels on the upper side of spacing units P10 and P9, and separate beams C and D are emitting to the two pixels on the upper side of spacing units P8 and P7.

[0099] Thus, the four pixels of the pitch units P7 and P8 are exposed twice each.

[0100] Perform tracking reset to align the beam drawing position with the lower left pixel of each pitch unit. Fig.14As shown in (d), the beam array is moved in the x direction while the stage is tracked, and the beam is emitted to the two pixels on the lower side of the pitch unit.

[0101] Fig.14 (d) shows the state in which separate beams a and b emit to the two pixels on the lower side of spacing units P16 and P15, separate beams c and d emit to the two pixels on the lower side of spacing units P14 and P13, separate beams A and B emit to the two pixels on the lower side of spacing units P12 and P11, and separate beams C and D emit to the two pixels on the lower side of spacing units P10 and P9.

[0102] Thus, the four pixels of the pitch units P9 and P10 are exposed twice each.

[0103] When the number of tracking times required for irradiation of one pitch unit is M (M is an integer greater than or equal to 2), M segments defining the emission order corresponding to a plurality of different pixels in the pitch unit are prepared and stored in the storage unit 140. The segment defines the pixels emitted in one pitch unit during one tracking period and the emission order. Fig.13 , Fig.14 In the example shown, the number of traces required to irradiate one pitch unit is 4. Fig.15 The four segments 1 to 4 shown are drawn by assigning a repetition order to different segments for each tracking.

[0104] When the segment is regarded as a two-dimensional matrix in which pixels to which emission is assigned are 1 and other pixels are 0, each element of the sum of matrices corresponding to segments 1 to 4 coincides with the intra-fringe multiplicity.

[0105] The 4 pixels of the pitch units P1 and P2 are Fig.16 That is, the drawing based on the segment 1, the drawing based on the segment 2, the drawing based on the segment 3, and the drawing based on the segment 4 are performed in sequence.

[0106] The 4 pixels of the pitch units P3 and P4 are Fig.16 That is, the drawing based on the segment 2, the drawing based on the segment 3, the drawing based on the segment 4, and the drawing based on the segment 1 are performed in sequence.

[0107] The 4 pixels of the pitch units P5 and P6 are Fig.16 That is, the drawing based on the segment 3, the drawing based on the segment 4, the drawing based on the segment 1, and the drawing based on the segment 2 are performed in sequence.

[0108] The 4 pixels of the pitch units P7 and P8 are Fig.16That is, the drawing based on the segment 4, the drawing based on the segment 1, the drawing based on the segment 2, and the drawing based on the segment 3 are performed in sequence.

[0109] In this way, different emission orders can be assigned to a plurality of pitch units in a stripe region according to different sections of each tracking application, thereby reducing the system error caused by the emission order.

[0110] When performing such drawing processing, the area ratio calculation unit 111 reads the drawing data from the storage unit 140 , calculates the pattern area density ρ(x) in the pixel 36 for each pixel 36 , and creates an area ratio map. This processing is performed for each stripe region 32 , for example.

[0111] In addition, the area ratio calculation unit 111 virtually divides the drawing area (e.g., the stripe area 32) into a plurality of proximity grid areas (grid areas for proximity effect correction calculation) in a grid shape with a predetermined size. The size of the proximity grid area is preferably set to about 1 / 10 of the influence range of the proximity effect, for example, about 1 μm. The area ratio calculation unit 111 reads the drawing data from the storage unit 140, and calculates the pattern area density ρ′ of the pattern arranged in the proximity grid area for each proximity grid area.

[0112] Next, the area ratio calculation unit 111 calculates the proximity effect correction coefficient Dp(x) (corrected irradiation amount) for correcting the proximity effect according to each proximity grid area. The unknown proximity effect correction irradiation coefficient Dp(x) can be defined by a threshold model for proximity effect correction that uses the backscatter coefficient η, the irradiation amount threshold Dth of the threshold model, the pattern area density ρ′, and the distribution function g(x), which is the same as the conventional method.

[0113] The irradiation amount calculation unit 117 calculates the incident irradiation amount D(x) (dose, exposure amount) for irradiating the pixel 36 for each pixel 36. The incident irradiation amount D(x) is calculated as, for example, a value obtained by multiplying a preset reference irradiation amount Dbase by the pattern area density ρ(x) and the proximity effect correction coefficient Dp(x). The reference irradiation amount Dbase can be defined, for example, by Dth / (1 / 2+η).

[0114] The irradiation amount calculation unit 117 calculates the irradiation amount of each beam (individual beam) of the multi-beam for each shot. For example, the irradiation amount calculation unit 117 divides the incident irradiation amount D(x) of the pixel irradiated with the individual beam by the multiplicity to calculate the irradiation amount per path.

[0115] The drawing control unit 118 converts the irradiation amount of each beam calculated by the irradiation amount calculation unit 117 into irradiation time data and transmits it to the deflection control circuit 130. The deflection control circuit 130 controls the on and off of each blanker of the blanking aperture array substrate 204 based on the irradiation time data. In addition, the deflection control circuit 130 controls the deflection amount of the deflectors 208 and 209 to become Fig.13 , Fig.14 The firing order shown in .

[0116] In the stripe multiple drawing method, as another example of a drawing method for assigning different emission orders to a plurality of pitch units in a stripe area, the method uses Figures 17 to 20 The case where there are many pixels in a pitch unit is described.

[0117] like Fig.17 As shown, a beam array composed of 3×18 individual beams (beamlets) is used to perform intra-fringe multiplexing with a multiplicity of 2. The pitch unit is composed of 3 pixels×3 pixels=9 pixels.

[0118] The number of tracking times required for irradiation of one pitch unit is set to 6. Fig.18 Segments 1 to 6 are stored in the storage unit 140. When the segments are regarded as a two-dimensional matrix in which pixels assigned with emission are 1 and other pixels are 0, the value of each element of the sum of segments 1 to 6 is 2 (= intra-fringe multiplicity).

[0119] First, if Fig.19 As shown in (a), while the work stage is tracking, the three pixels of the pitch unit are emitted in the emission order of segment 1. Fig.19 (a) shows a state where the individual beams a, b, and c are radiated to three pixels in the pitch units P3, P2, and P1. After the radiated three pixels, tracking reset is performed.

[0120] Start bench tracking again, such as Fig.19 As shown in (b), the three pixels of the pitch unit are emitted in the emission order of segment 2. Fig.19 (b) shows a state where the individual beams a to f are radiated to three pixels in the pitch units P6 to P1. After the radiated three pixels, tracking reset is performed.

[0121] Start bench tracking again, such as Fig.19 As shown in (c), the three pixels of the pitch unit are emitted in the emission order of segment 3. Fig.19 (c) shows a state where the individual beams a to i are radiated to three pixels in the pitch units P9 to P1. After the radiated three pixels, tracking reset is performed.

[0122] Start bench tracking again, such as Fig. 20 As shown in (a), the three pixels of the pitch unit are emitted in the emission order of segment 4. Fig. 20 (a) shows a state where the individual beams a to i and the individual beams A to C are radiated to three pixels in the pitch units P12 to P1. After the radiated three pixels, tracking reset is performed.

[0123] Start bench tracking again, such as Fig. 20 As shown in (b), the three pixels of the pitch unit are emitted in the emission order of segment 5. Fig. 20 (b) shows a state where the individual beams a to i and the individual beams A to F are radiated to three pixels in the pitch units P15 to P1. After the radiated three pixels, tracking reset is performed.

[0124] Start bench tracking again, such as Fig. 20 As shown in (c), the three pixels of the pitch unit are emitted in the emission order of segment 6. Fig. 20 (c) shows a state where the individual beams a to i and the individual beams A to I are radiated to three pixels in the pitch units P18 to P1.

[0125] Thus, the nine pixels of the pitch units P1 to P3 are exposed twice each. In this example, each segment has a complex emission sequence including both deflection in the x direction and deflection in the y direction, which can further enhance the effect of reducing the systematic error caused by the multiple drawing.

[0126] In the case of a systematic drift depending on the emission deflection direction, it is preferable to prepare a section with the emission order reversed. For example, it is known that the emission position drifts in the -x direction from the design position when the beam is deflected in the +x direction, and the emission position drifts in the +x direction from the design position when the beam is deflected in the -x direction.

[0127] In this case, if Fig.21 As shown, by using segments with the same emitted pixels but in opposite emission orders, errors can be eliminated and the position accuracy of the depicted pattern can be further improved.

[0128] like Fig.18 As shown, when the same number of segments as the number of tracking times M required for irradiation of one pitch unit is regarded as a two-dimensional matrix in which the pixels assigned to emission are 1 and the pixels other than 0 are assigned, the elements of the sum of the M segments can be consistent with the multiplicity within the stripe. As long as this restriction is met, there are no other restrictions on the emission order, and the emission order can also be a random order using random numbers.

[0129] In the above embodiment, different segments may be used for each stripe area. Figures 17 to 20 In the example shown, segments 1 to 6 are used in the depiction of the first stripe region. Segments 7 to 12 different from segments 1 to 6 are used in the depiction of the second stripe region. By using different segments for each stripe region, it is possible to reduce the systematic error caused by the emission order not only in the x direction but also in the y direction.

[0130] By changing the order in which the segments are applied per stripe region, it is also possible to reduce the systematic errors caused by the emission sequence in the y direction. Figures 17 to 20 In the example shown, in the first stripe region, the drawing is repeated in the order of segment 1, segment 2, segment 3, segment 4, segment 5, and segment 6. In the second stripe region, the drawing is repeated in the order of segment 2, segment 4, segment 5, segment 1, segment 6, and segment 3. In the third stripe region, the drawing is repeated in the order of segment 5, segment 1, segment 6, segment 3, segment 2, and segment 4.

[0131] In addition, in the above-mentioned embodiment, an example is shown in which the timing of beam switching of the irradiation beam spacing unit corresponds to the timing of tracking reset, but the present invention is not limited to this configuration. For example, it is also possible to add tracking reset between each emission when a certain single beam emits each pixel in the beam spacing unit. In other words, it is also possible to perform tracking reset for each emission. In this case, the area for generating the segment is a unit defined by the maximum area irradiated by one single beam.

[0132] In addition, the present invention is not limited to the above-mentioned embodiments as it is, and in the implementation stage, the constituent elements can be deformed and concretized within the scope of the main purpose. For example, in the above-mentioned embodiment, the case of a multiplicity of 2 in the stripes is described, but the multiplicity is not limited to 2, and can also be 4, 8, etc. In the above-mentioned embodiment, a charged particle multi-beam device that controls the charged particle beam by a blanking aperture array is described, but it can also be applied to a multi-charged particle beam drawing device that does not use a blanking aperture and a multi-laser beam drawing device that uses a digital micromirror device (DMD). In addition, various inventions can be formed by appropriate combinations of multiple constituent elements disclosed in the above-mentioned embodiments. For example, several constituent elements can be deleted from all the constituent elements shown in the embodiment. Moreover, the constituent elements of different embodiments can also be appropriately combined.

[0133] Description of Reference Numerals

[0134] 100 Drawing Device

[0135] 110 Control Computer

[0136] 111 Area ratio calculation unit

[0137] 117 Exposure Calculation Unit

[0138] 118 Drawing control unit

Claims

1. A multi-beam drawing method, comprising: dividing a drawing area of ​​a substrate on a workbench of a beam array irradiated with a multi-beam into a plurality of stripe areas with a predetermined width in a direction perpendicular to a drawing advancing direction, and dividing the area into a plurality of pixels as an irradiation unit area of ​​each individual beam constituting the multi-beam, and drawing is performed with a predetermined intra-strip multiplicity N for each stripe area, wherein: The N is an integer greater than 2, and the multi-beam delineation method comprises the following steps: Generate M different segments, the M segments define emission orders corresponding to a plurality of pixels belonging to each of a plurality of units obtained by dividing the stripe region, wherein M is an integer greater than 2, While deflecting the multi-beam, a first single beam is used to irradiate a plurality of pixels in the unit using an m-1th segment, and then a second single beam different from the first single beam is used to irradiate a plurality of pixels in the unit using an mth segment, wherein m is an integer of 2≤m≤M, By repeatedly performing illumination using the M types of segments in sequence, all pixels in each unit are rendered at the multiplicity N.

2. The multi-beam delineation method according to claim 1, wherein: The unit is a pitch unit obtained by dividing the stripe area according to the inter-beam pitch size of the multi-beam used for drawing, While tracking by deflecting the multi-beam in a manner following the movement of the worktable, the first single beam is used to irradiate the multiple pixels in the pitch unit using the m-1th segment, and after the tracking is reset, the second single beam is used to irradiate the multiple pixels in the pitch unit using the mth segment.

3. The multi-beam delineation method according to claim 1, wherein: The unit is obtained by dividing the stripe area by the maximum area irradiated by a single beam among the multiple beams.

4. The multi-beam delineation method according to claim 1, wherein: When the M types of segments are regarded as two-dimensional matrices in which pixels assigned with emission are 1 and pixels not assigned with emission are 0, the values ​​of each element of the sum of the two-dimensional matrices corresponding to the M types of segments are consistent with the specified multiplicity.

5. The multi-beam delineation method according to claim 1, wherein: In two of the M types of segments, the emitted pixels are the same, and the emission order is opposite.

6. The multi-beam delineation method according to claim 1, wherein: The M types of segments used when drawing the first stripe area are different from the M types of segments used when drawing the second stripe area.

7. A multi-beam delineation device, wherein: have: A workbench, on which a substrate for drawing an object is placed and which can be moved; A multi-beam forming unit for forming a multi-beam; a storage unit storing drawing data and M types of segments different from each other, the M types of segments being generated by defining emission orders corresponding to a plurality of pixels belonging to each of a plurality of units obtained by dividing a plurality of stripe regions respectively, the plurality of stripe regions being obtained by dividing the drawing region of the substrate by a predetermined width in a direction perpendicular to a drawing advancing direction, wherein M is an integer greater than or equal to 2; and a drawing control unit that controls drawing using the drawing data and the segment, The pixel is a unit area of ​​illumination of each individual beam constituting the multi-beam, The depiction control unit controls the deflection of the multi-beam while irradiating the multiple pixels in the unit using the m-1th segment through the first single beam of the multi-beam, and then irradiates the multiple pixels in the unit using the mth segment through the second single beam different from the first single beam, to depict each of the multiple stripe areas with a specified intra-stripe multiplicity N, wherein m is an integer of 2≤m≤M, and N is an integer greater than 2.

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