Multi-charged particle beam writing method, multi-charged particle beam writing apparatus, and program

Abstract

PURPOSE: To provide a method that can reduce pattern positional deviation due to distortion of the beam array shape.CONSTITUTION: A multi-charged particle beam writing method according to an embodiment of the present invention includes the steps of setting a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas in which a writing area of a substrate is divided into a mesh shape by the inter-beam pitch size of the multi-charged particle beam on the substrate, setting a writing order for the plurality of groups for each processing number of the multiple writing process such that the writing order of the plurality of groups differs for each processing number indicating the processing order of the multiple writing process, and performing multiple writing in accordance with the writing order of the plurality of groups for each processing number of the set multiple writing process.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a multi-charged particle beam lithography method, a multi-charged particle beam lithography apparatus, and a program, and more particularly to a technique for correcting positional deviation caused by beam array distortion on a substrate surface in a multi-beam lithography apparatus. [Background technology]

[0002] Lithography technology, which is responsible for the advancement of miniaturization of semiconductor devices, is the only extremely important process in semiconductor manufacturing that generates patterns. In recent years, with the increasing integration density of LSIs, the circuit line width required for semiconductor devices has been getting finer year by year. Here, electron beam (EB) lithography technology has inherently excellent resolution, and lithography is carried out using an electron beam to draw on wafers, etc.

[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 such a lithography system, for example, an electron beam emitted from an electron gun is passed through a mask with multiple holes to form multiple beams, each of which is blanked, and the unblocked beams are reduced in size by an optical system, deflected by a deflector, and irradiated onto the desired position on the sample.

[0004] In multi-beam lithography, distortion of the beam array shape affects the positional accuracy and dimensional accuracy of the lithography pattern. To address this issue, the averaging effect can be improved by increasing the number of passes in which the stage repeatedly moves, shifting the irradiation area in the y direction after each stripe lithography, so that the same stripe area is multiplexed. However, there is a limit to how much distortion of the beam array shape can be reduced. Furthermore, in multiple lithography in which stripes are repeatedly lithographed, the same position is repeatedly lithographed with the same beam or beams that are relatively close to each other, which poses a problem of insufficient reduction in the effects of distortion of the beam array shape.

[0005] Here, a method has been disclosed in which the beams are irradiated in a first shot order in a first pass, and after the first pass is completed, the stage is moved in the opposite direction in a second pass in which the beams are irradiated in a second shot order that is different from the first shot order on a pixel-by-pixel basis, thereby reducing the effect of distortion in the beam array shape (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2023-042359 Summary of the Invention [Problem to be solved by the invention]

[0007] One aspect of the present invention provides a method capable of reducing pattern misalignment due to distortion of the beam array shape. [Means for solving the problem]

[0008] A multi-charged particle beam writing method according to one aspect of the present invention includes: a step of setting a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a writing area of ​​a substrate into a mesh-like shape based on a beam pitch size of the multi-charged particle beam on the substrate; setting a drawing order for the plurality of groups for each processing number of the multiple drawing processing so that the drawing order for the plurality of groups differs for each processing number indicating the processing order of the multiple drawing processing; a step of performing multiple drawing in accordance with a drawing order of a plurality of groups for each processing number of the set multiple drawing process; The present invention is characterized by the following.

[0009] Furthermore, when performing multiple drawing, it is preferable to perform multiple drawing in accordance with the drawing order of multiple groups for each processing number of the set multiple drawing process during one stage movement in a direction parallel to the drawing direction by repeating tracking control for making the irradiation area of ​​the multi-charged particle beam follow the movement of the substrate placed on the continuously moving stage and tracking reset for resetting the position of the irradiation area of ​​the multi-charged particle beam, and performing drawing processing of the processing number whose processing number is changed in sequence for each tracking cycle, and during the tracking control in the drawing processing of the processing number, each beam of the multi-charged particle beam draws all beam irradiation unit areas of the same group within any one of different pitch cell areas located within the irradiation area of ​​the multi-charged particle beam.

[0010] It is also preferable to shift the drawing order of the multiple groups for each processing number of the multiple drawing process.

[0011] It is also preferable to shift the irradiation area of ​​the multi-charged particle beam in a direction perpendicular to the writing direction by a size less than the size of the beam irradiation unit area for each processing number of the multiple writing processing.

[0012] A program to be executed by a computer according to one aspect of the present invention comprises: a function of setting a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a drawing area of ​​the substrate into a mesh-like shape based on the inter-beam pitch size of the multi-charged particle beam on the substrate; a function of setting a drawing order of a plurality of groups for each processing number of the multiple drawing process so that the drawing order of the plurality of groups differs for each processing number indicating the processing order of the multiple drawing process; a function of storing in a storage device the drawing order of the plurality of groups for each processing number of the set multiple drawing processing; a function of reading out from the storage device a drawing order of a plurality of groups for each processing number of the set multiple drawing process, and performing multiple drawing in accordance with the drawing order of the plurality of groups for each processing number of the set multiple drawing process; The present invention is characterized by the following.

[0013] A multi-charged particle beam writing apparatus according to one aspect of the present invention comprises: a group setting unit that sets a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a drawing area of ​​the substrate into a mesh-like pattern based on the inter-beam pitch size of the multi-charged particle beam on the substrate; a group order setting unit that sets a drawing order of the plurality of groups for each processing number of the multiple drawing processes so that the drawing order of the plurality of groups differs for each processing number that indicates the processing order of the multiple drawing processes; a drawing control unit that performs multiple drawing in accordance with a drawing order of a plurality of groups for each processing number of the set multiple drawing processes; The present invention is characterized by the following.

[0014] A multi-charged particle beam writing method according to another aspect of the present invention comprises: a step of setting a writing order of a plurality of beam irradiation unit areas in a plurality of pitch cell areas for each processing number indicating a processing order of the multiple writing processes, such that the writing order of a plurality of beam irradiation unit areas in a plurality of pitch cell areas obtained by dividing a writing area of ​​the substrate into a mesh shape by the inter-beam pitch size of the multi-charged particle beam on the substrate differs for each processing number of the multiple writing processes; a step of performing multiple drawing in accordance with a drawing order of a plurality of beam irradiation unit areas in a plurality of pitch cell areas for each set process number of the multiple drawing process during one movement of the stage in a direction parallel to the drawing direction, by performing drawing processes of process numbers whose process numbers are sequentially changed in each tracking cycle, in which a tracking control for making the irradiation area of ​​the multi-charged particle beam follow the movement of a substrate placed on a continuously moving stage and a tracking reset for resetting the position of the irradiation area of ​​the multi-charged particle beam are repeated, and by performing the drawing processes of the process numbers whose process numbers are sequentially changed in each tracking cycle, in which each beam of the multi-charged particle beam draws the same beam irradiation unit area in any one of different pitch cell areas located in the irradiation area of ​​the multi-charged particle beam during the tracking control in the drawing processes of the process numbers; The present invention is characterized by the following. [Effects of the Invention]

[0015] According to one aspect of the present invention, it is possible to reduce pattern positional deviations caused by distortion of the beam array shape. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram showing a configuration of a drawing device according to a first embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing the configuration of a shaping aperture array substrate according to the first embodiment. [Figure 3] 2 is a cross-sectional view showing the configuration of a blanking aperture array mechanism in the first embodiment. FIG. [Figure 4] FIG. 2 is a conceptual diagram for explaining an example of a drawing operation in the first embodiment. [Figure 5] 3 is a diagram showing an example of a multi-beam irradiation area and a pixel to be written in the first embodiment. FIG. [Figure 6] FIG. 2 is a flowchart showing an example of main steps of the writing method according to the first embodiment. [Figure 7] 5 is a diagram showing an example of a sub-illumination region and an example of a group according to the first embodiment. FIG. [Figure 8] FIG. 2 is a diagram for explaining a part of an example of a multi-beam writing operation according to the first embodiment. [Figure 9] FIG. 10 is a diagram for explaining another part of the example of the multi-beam writing operation according to the first embodiment. [Figure 10] 10 shows an example of the beam numbers used to write the sub-irradiation regions in the first embodiment. [Figure 11] 1 shows an example of the average beam numbers of a plurality of beams that write at each position in the first embodiment and the first comparative example. [Figure 12] 10 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number of the multiple rendering process in the first embodiment. [Figure 13] 10 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number in the multiple rendering process in Comparative Example 1 of the first embodiment. [Figure 14]10 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number in the multiple rendering process in Comparative Example 2 of Embodiment 1. [Figure 15] 10 shows an example of the relationship between the average error value of multiple writing processes for pixels at the same position in each sub-irradiation region and the pixel position in the first embodiment. [Figure 16] 10 shows an example of the relationship between the average error value of multiple drawing processes for pixels at the same position in each sub-irradiation region and the pixel position in Comparative Example 1 of Embodiment 1. [Figure 17] 10 shows an example of the relationship between the average error value of multiple drawing processes for pixels at the same position in each sub-irradiation region and the pixel position in Comparative Example 2 of Embodiment 1. [Figure 18] FIG. 10 is a flowchart showing an example of main steps of a writing method according to the second embodiment. [Figure 19] FIG. 10 is a diagram for explaining a part of an example of a multi-beam writing operation according to the second embodiment. [Figure 20] FIG. 10 is a diagram for explaining another part of the example of the multi-beam writing operation in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following embodiments, a configuration using an electron beam will be described as an example of a charged particle beam, but the charged particle beam is not limited to an electron beam and may be a beam using charged particles such as an ion beam.

[0018] Embodiment 1 FIG. 1 is a conceptual diagram showing the configuration of a lithography apparatus according to the first embodiment. In FIG. 1, the lithography apparatus 100 includes a lithography mechanism 150 and a control circuit 160. The lithography apparatus 100 is an example of a multi-charged particle beam lithography apparatus and also an example of a multi-charged particle beam exposure apparatus. The lithography mechanism 150 includes an electron lens barrel 102 (electron beam column) and a lithography chamber 103. Inside the electron lens barrel 102, an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a main deflector 208, and a sub-deflector 209 are arranged.

[0019] An XY stage 105 is disposed within the patterning chamber 103. A sample 101, such as a mask, which will be the patterned substrate during patterning (exposure) is disposed on the XY stage 105. The sample 101 includes an exposure mask used in manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured. The sample 101 also includes a mask blank coated with resist and on which nothing has yet been patterned. A mirror 210 for measuring the position of the XY stage 105 is also disposed on the XY stage 105.

[0020] The control system circuit 160 includes a control computer 110, a memory 112, a deflection control circuit 130, digital-to-analog conversion (DAC) amplifier units 132 and 134, a lens control circuit 136, a stage control mechanism 138, a stage position measurement device 139, and storage devices 140 and 142 such as magnetic disk drives. The control computer 110, the memory 112, the deflection control circuit 130, the lens control circuit 136, the stage control mechanism 138, the stage position measurement device 139, and storage devices 140 and 142 are connected to one another via a bus (not shown). The deflection control circuit 130 is connected to the DAC amplifier units 132 and 134 and a blanking aperture array mechanism 204. The sub-deflector 209 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 132. The main deflector 208 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 134. The lens group including the illumination lens 202 , the reduction lens 205 , and the objective lens 207 is controlled by a lens control circuit 136 .

[0021] The position of the XY stage 105 is controlled by driving motors (not shown) for each axis controlled by a stage control mechanism 138. A stage position measuring device 139 receives light reflected from a mirror 210 and measures the position of the XY stage 105 based on the principle of laser interferometry.

[0022] The control computer 110 includes a group setting unit 50, a group order setting unit 52, a layer switching unit 54, a Y-shift unit 56, a writing data processing unit 70, a writing control unit 72, and a transfer processing unit 74. Each of the "units" such as the group setting unit 50, the group order setting unit 52, the layer switching unit 54, the Y-shift unit 56, the writing data processing unit 70, the writing control unit 72, and the transfer processing unit 74 has a processing circuit. Such a processing circuit may include, for example, an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each of the "units" may use a common processing circuit (the same processing circuit) or different processing circuits (separate processing circuits). Information input to and output from the group setting unit 50, the group order setting unit 52, the layer switching unit 54, the Y-shift unit 56, the writing data processing unit 70, the writing control unit 72, and the transfer processing unit 74, as well as information being calculated, is stored in the memory 112 each time.

[0023] The drawing operation of the drawing apparatus 100 is controlled by a drawing control unit 72. In other words, the drawing control unit 72 (an example of a control circuit) controls the drawing mechanism 150. In addition, a transfer process of the irradiation time data of each shot to the deflection control circuit 130 is controlled by a transfer processing unit 74.

[0024] Furthermore, drawing data (chip data) is input from outside the drawing device 100 and stored in the storage device 140. The chip data defines information on a plurality of figure patterns that constitute the chip pattern. Specifically, for each figure pattern, for example, the coordinates of each vertex are defined in the order in which the figure is formed. Alternatively, for each figure pattern, for example, a figure code, coordinates, size, etc. are defined.

[0025] 1 shows the configuration necessary for explaining the first embodiment. The drawing device 100 may also include other configurations that are normally required.

[0026] FIG. 2 is a conceptual diagram showing the configuration of a shaping aperture array substrate in the first embodiment. In FIG. 2, holes (openings) 22 are formed in a matrix of p columns (y direction) by q columns (x direction) (p, q≧2) at a predetermined arrangement pitch in shaping aperture array substrate 203. The example in FIG. 2 shows, for example, a case where 24×24 columns of holes 22 are formed in the vertical and horizontal directions (x, y directions). The number of holes 22 is not limited to this. For example, 512×512 columns of holes 22 may be formed. Each hole 22 is formed as a rectangle of the same size and shape. Alternatively, it may be a circle of the same diameter. Multiple beams 20 are formed when portions of electron beam 200 pass through these multiple holes 22. In other words, shaping aperture array substrate 203 forms multiple beams 20.

[0027] FIG. 3 is a cross-sectional view showing the configuration of the blanking aperture array mechanism according to the first embodiment. As shown in FIG. 3, the blanking aperture array mechanism 204 includes a blanking aperture array substrate 31, which is made of a semiconductor substrate such as silicon, and is disposed on a support base 33. In a central membrane region 330 of the blanking aperture array substrate 31, passage holes 25 (openings) for passing through each beam of the multi-beams 20 are formed at positions corresponding to the holes 22 of the shaping aperture array substrate 203 shown in FIG. 2. Pairs of control electrodes 24 and counter electrodes 26 (blankers: blanking deflectors) are disposed at positions facing each other across the corresponding passage holes 25 among the plurality of passage holes 25. Furthermore, a control circuit 41 (logic circuit) is disposed inside the blanking aperture array substrate 31 near each passage hole 25, which applies a deflection voltage to the control electrode 24 for each passage hole 25. The counter electrodes 26 for each beam are connected to ground.

[0028] An amplifier (an example of a switching circuit), not shown, is disposed within the control circuit 41. As an example of the amplifier, a CMOS (Complementary MOS) inverter circuit serving as a switching circuit is disposed. To the input (IN) of the CMOS inverter circuit, either an L (low) potential (e.g., ground potential) that is lower than the threshold voltage or an H (high) potential (e.g., 1.5 V) that is equal to or higher than the threshold voltage is applied as a control signal. In the first embodiment, when an L potential is applied to the input (IN) of the CMOS inverter circuit, the output (OUT) of the CMOS inverter circuit applied to the control circuit 41 becomes a positive potential (Vdd), and the corresponding beam is deflected by an electric field due to the potential difference with the ground potential of the counter electrode 26, and is controlled so that the beam is turned OFF by being shielded by the limiting aperture substrate 206. On the other hand, when an H potential is applied to the input (IN) of the CMOS inverter circuit (active state), the output (OUT) of the CMOS inverter circuit becomes the ground potential, and there is no potential difference with the ground potential of the opposing electrode 26, so the corresponding beam is not deflected, and the beam is controlled to be ON by passing through the limiting aperture substrate 206. Blanking control is performed by this deflection.

[0029] Next, a specific example of the operation of the drawing mechanism 150 will be described. An electron beam 200 emitted from an electron gun 201 (emission source) is illuminated by an illumination lens 202 almost perpendicularly onto the entire shaping aperture array substrate 203. A plurality of rectangular holes 22 (openings) are formed in the shaping aperture array substrate 203, and the electron beam 200 illuminates an area including all of the holes 22. Portions of the electron beam 200 irradiated onto the positions of the holes 22 pass through the holes 22 of the shaping aperture array substrate 203, thereby forming, for example, a rectangular multibeam (multiple electron beams) 20. The multibeam 20 passes through corresponding blankers of a blanking aperture array mechanism 204. Each blanker performs blanking control on the beams passing through it so that the beams are turned on for a set drawing time (irradiation time).

[0030] The multi-beams 20 that pass through the blanking aperture array mechanism 204 are reduced by the reduction lens 205 and travel toward a central hole formed in the limiting aperture substrate 206. Here, the electron beams deflected by the blankers of the blanking aperture array mechanism 204 are shifted from the central hole of the limiting aperture substrate 206 and are blocked by the limiting aperture substrate 206. On the other hand, the electron beams that are not deflected by the blankers of the blanking aperture array mechanism 204 pass through the central hole of the limiting aperture substrate 206 as shown in FIG. 1. In this way, the limiting aperture substrate 206 blocks each beam that is deflected by the blankers of the blanking aperture array mechanism 204 to be in a beam-off state. Then, each beam of one shot is formed by the beams that pass through the limiting aperture substrate 206 from when the beams are turned on until when they are turned off. The multibeams 20 that have passed through the limiting aperture substrate 206 are focused by the objective lens 207 to form a pattern image with the desired reduction ratio, and the entire multibeams 20 that have passed through the limiting aperture substrate 206 are deflected in the same direction by the main deflector 208 and the sub-deflector 209, and each beam is irradiated onto its respective irradiation position on the sample 101. Furthermore, for example, when the XY stage 105 is moving continuously, tracking control is performed by the main deflector 208 so that the beam irradiation position follows the movement of the XY stage 105. Ideally, the multibeams 20 that are irradiated at one time are arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes 22 in the shaping aperture array substrate 203 by the desired reduction ratio described above.

[0031] Fig. 4 is a conceptual diagram for explaining an example of the writing operation in embodiment 1. As shown in Fig. 4, the writing region 30 (bold line) on the sample 101 is virtually divided, for example, in the y direction into a plurality of rectangular stripe regions 32 with a predetermined width. The example in Fig. 4 shows a case where the writing region 30 on the sample 101 is divided, for example, in the y direction, into a plurality of stripe regions 32 with a width that is substantially the same as the size of the designed irradiation region 34 (writing field) that can be irradiated with a single irradiation of the multibeam 20.

[0032] The example of FIG. 4 illustrates a case where multiple rendering is performed with a multiplicity of 2. For the first rendering process, which has a processing number of 1 indicating the processing order of the multiple rendering process, a first stripe layer is set, which is composed of multiple stripe regions 32 obtained by dividing the rendering area 30. For the second rendering process, which has a processing number of 2, a second stripe layer is set, which is composed of multiple stripe regions 32 shifted in the y direction relative to the first stripe layer by half the pixel size of a pixel 36 (described later). Thus, in the example of FIG. 4, two stripe layers, a first stripe layer and a second stripe layer, are set. Therefore, by combining the first stripe layer and the second stripe layer, multiple stripe regions 32 are set that are aligned and partially overlap each other in the y direction. The example of FIG. 4 illustrates a case where adjacent stripe regions 32 in the y direction overlap each other except for a portion. It is also preferable to set one extra stripe region 32 in each stripe layer in the -y direction from the end of the rendering area 30. The multiplicity is not limited to 2 and may be 3 or more.

[0033] For example, when performing multiple rendering with a multiplicity of 4, a first stripe layer is set for the first rendering process, which has a processing number of 1 in the multiple rendering process. A second stripe layer is set for the second rendering process, which has a processing number of 2 in the multiple rendering process. A third stripe layer is set for the third rendering process, which has a processing number of 3 in the multiple rendering process. A fourth stripe layer is set for the fourth rendering process, which has a processing number of 4 in the multiple rendering process. It is preferable that each stripe layer is set so that its position is shifted from the others in the y direction by 1 / 4 of the pixel size.

[0034] Furthermore, the above-described positional shift less than the pixel size is not limited to the y direction, but may also be applied to the x direction as shown in Fig. 4. Next, an example of the drawing operation will be described.

[0035] First, the XY stage 105 is moved and adjusted so that the irradiation area 34 of the multibeam 20 is positioned at the left end of the first stripe region 32 of the first stripe layer, or at a position further to the left. Then, when writing the first stripe region 32, the XY stage 105 is moved, for example, in the −x direction, thereby relatively progressing writing in the x direction. The XY stage 105 is moved continuously, for example, at a constant speed. In the first embodiment, writing is performed on all of the first stripe regions 32 of each stripe layer during one movement (one pass) of the XY stage 105 in the −x direction.

[0036] After the first stripe region 32 of each stripe layer has been written, the stage position is moved in the -y direction by the width of the stripe region 32. As a result, the written stripe region 32 is shifted in the y direction by the width of the stripe region 32.

[0037] Next, the irradiation area 34 of the multibeam 20 is adjusted to be located at the left end of the second stripe area 32 of the first stripe layer, or at a position further to the left. Then, by moving the XY stage 105, for example, in the -x direction, writing proceeds relatively in the x direction. This results in writing of the second stripe area 32 of each stripe layer. In this way, writing of all the second stripe areas 32 of each stripe layer is completed during one movement (one pass) of the XY stage 105 in the -x direction. By repeating this process thereafter, writing of all the stripe areas 32 of each stripe layer is completed. The stripe layer is switched during each pass by Y-deflection by the main deflector 208, which will be described later. As a result, multiple drawing is performed in the stripe region 32 of each stripe layer.

[0038] 4 shows the case where each stripe region 32 is written in the same direction, but this is not limiting. For example, the stripe region 32 to be written next to the stripe region 32 written in the x direction may be written in the -x direction by moving the XY stage 105 in the x direction, for example. By writing while alternating directions in this way, the stage movement time can be shortened, and ultimately the writing time can be shortened. In one shot, multiple shot patterns, up to the same number as the holes 22, are formed at once by the multi-beams formed by passing through each hole 22 in the shaping aperture array substrate 203.

[0039] FIG. 5 shows an example of a multibeam irradiation area and a target pixel for drawing in the first embodiment. In FIG. 5, the stripe area 32 is divided into a plurality of mesh areas, for example, based on the beam size of the multibeam 20. Each mesh area corresponds to a target pixel 36 (beam irradiation unit area, irradiation position). The size of the target pixel 36 is not limited to the beam size and may be any size regardless of the beam size. For example, the size may be 1 / n (n is an integer greater than or equal to 1) of the beam size. The example of FIG. 5 shows a case where the target region for drawing on the sample 101 is divided, for example, in the y direction, into a plurality of stripe areas 32, each having a width substantially equal to the size of the irradiation region 34 (drawing field) that can be irradiated with one irradiation of the multibeam 20. The size of the rectangular irradiation region 34 in the x direction can be defined by the number of beams in the x direction multiplied by the beam pitch in the x direction. The size of the rectangular irradiation region 34 in the y direction can be defined by the number of beams in the y direction multiplied by the beam pitch in the y direction. In the example of Figure 5, for example, a 24 x 24 array of multi-beams is shown as an 8 x 8 array of multi-beams. A plurality of pixels 28 (beam drawing positions) that can be irradiated with one shot of the multi-beams 20 are shown within the irradiation area 34. The pitch between adjacent pixels 28 is the inter-beam pitch of each of the multi-beams. A rectangular area surrounded by the size of the inter-beam pitch in the x and y directions constitutes one sub-irradiation area 29 (pitch cell area). In the example of Figure 5, each sub-irradiation area 29 is shown as being composed of, for example, 4 x 4 pixels.

[0040] Fig. 6 is a flowchart showing an example of main steps of the writing method according to the first embodiment. In Fig. 6, the writing method according to the first embodiment performs a series of steps including a group setting step (S102), a group order setting step (S104), a multiple writing step (S108), and a determination step (S140). The multiple writing step (S108) performs, as internal steps, a group shot (tracking control) step (S110), a tracking reset step (S112), a determination step (S120), a multiple writing process number switching step (S130), and a stripe position Y shift step (S132).

[0041] As a group setting step (S102), the group setting unit 50 sets multiple groups consisting of multiple pixels 36 within multiple sub-irradiation areas 29 (pitch cell areas) in which the stripe area 32 (an example of a drawing area) of the sample 101 (substrate) is divided into a mesh shape at the beam pitch size of the multi-beam 20 on the sample 101.

[0042] Fig. 7 is a diagram showing an example of a sub-irradiation area and an example of a group in the first embodiment. In the example of Fig. 7, each sub-irradiation area 29 is composed of, for example, 6 x 6 pixels 36. In the example of Fig. 7, one group is composed of six pixels arranged in the y direction that make up each column in the x direction. Therefore, in the example of Fig. 7, six groups 1 to 6 are composed. The number of pixels that compose such a group is preferably set to the number of pixels that are shot during one tracking control.

[0043] In the group order setting step (S104), the group order setting unit 52 sets the drawing order of the multiple groups for each processing number indicating the processing order of the multiple drawing processing so that the drawing order of the multiple groups differs for each processing number of the multiple drawing processing. In other words, when multiple drawing with a multiplicity of 4 is performed, the drawing orders are set so that the drawing order of the multiple groups when drawing each sub-irradiation region 29 in each stripe region 32 in the first stripe layer is different from the drawing order of the multiple groups when drawing each sub-irradiation region 29 in each stripe region 32 in the second stripe layer, the drawing order of the multiple groups when drawing each sub-irradiation region 29 in each stripe region 32 in the third stripe layer, and the drawing order of the multiple groups when drawing each sub-irradiation region 29 in each stripe region 32 in the fourth stripe layer are different. In this case, it is preferable to shift the drawing order of the multiple groups for each processing number of the multiple drawing processing. In other words, it is preferable to shift the cycles. In the example of FIG. 7 , in the first drawing process (first iteration) of process number 1 of the multiple drawing process, for example, the sub-illumination areas 29 are drawn in the order of groups 1, 2, 3, 4, 5, and 6. In the second drawing process (second iteration) of process number 2 of the multiple drawing process, for example, the sub-illumination areas 29 are drawn in the order of groups 6, 1, 2, 3, 4, and 5. In the third drawing process (third iteration) of process number 3 of the multiple drawing process, for example, the sub-illumination areas 29 are drawn in the order of groups 5, 6, 1, 2, 3, and 4. In the fourth drawing process (fourth iteration) of process number 4 of the multiple drawing process, for example, the sub-illumination areas 29 are drawn in the order of groups 4, 5, 6, 1, 2, and 3.

[0044] In the multiple lithography step (S108), first, the lithography data processing unit 70 reads chip data (lithography data) stored in the storage device 140 and generates irradiation time data for each pixel for each lithography process of each process number of the multiple lithography. For example, in a lithography process with a multiplicity of 4, a beam with a dose of, for example, 1 / 4 of the required dose is irradiated onto the target pixel for each lithography process of each process number. The irradiation time data is rearranged in shot order according to a preset lithography sequence. The irradiation time data is stored in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order. The lithography mechanism 150 lithographs a pattern on the sample 101 with the multibeam 20. The lithography control unit 72 controls the lithography operation by the lithography mechanism 150.

[0045] Then, under the control of the drawing control unit 72, the drawing mechanism 150 performs multiple drawing in accordance with the drawing order of the multiple groups for each processing number of the set multiple drawing process. In other words, the drawing control unit 72 performs multiple drawing in accordance with the drawing order of the multiple groups for each processing number of the set multiple drawing process. When performing multiple drawing, it is preferable to shift the irradiation area 34 of the multi-beam 20 in the y direction perpendicular to the drawing direction (x direction) by a size less than the pixel size for each processing number of the multiple drawing process.

[0046] In the first embodiment, when performing multiple drawing, the drawing mechanism 150 performs drawing processing of the multiple drawing processing with the processing number changed in sequence for each tracking cycle. In the tracking cycle, tracking control for making the irradiation area 34 of the multibeam 20 follow the movement of the sample 101 placed on the continuously moving XY stage 105 and tracking reset for resetting the position of the irradiation area 34 of the multibeam 20 are repeated. The drawing mechanism 150 performs drawing processing for the processing number in each tracking cycle, and during tracking control in the drawing processing for that processing number, each beam of the multiple child beams 20 draws all pixels 36 of the same group in any one of the mutually different sub-irradiation areas 29 located within the irradiation area 34 of the multi-beam 20. As a result, during one stage movement in a direction parallel to the drawing direction, multiple drawing is performed in accordance with the drawing order of multiple groups for each processing number of the set multiple drawing processing. This will be described in detail below.

[0047] FIG. 8 is a diagram for explaining a part of an example of a multi-beam writing operation according to the first embodiment. FIG. 9 is a diagram for explaining another part of the example of the multi-beam writing operation according to the first embodiment. 8 and 9 show a case where, for each stripe layer, writing is performed in each sub-irradiation region 29 with six different beams. The example of FIG. 8 also shows a writing operation in which the XY stage 105 continuously moves at a speed of a distance L corresponding to one beam pitch while writing one group (1 / 6 of the region) in each sub-irradiation region 29. The writing operation shown in the example of FIG. 8 shows a case where, for example, while the XY stage 105 moves the distance L corresponding to one beam pitch, six shots of the multi-beam 20 are performed in a shot cycle T while the sub-deflector 209 sequentially shifts the irradiation position (pixel 36), thereby writing (exposing) six different pixels constituting one group in the same sub-irradiation region 29. While writing (exposing) these six pixels, the main deflector 20 collectively deflects the entire multi-beam 20 to prevent the relative position of the irradiation region 34 with respect to the sample 101 from shifting due to the movement of the XY stage 105, thereby causing the irradiation region 34 to follow the movement of the XY stage 105. In other words, tracking control is performed. Six beam shots are emitted in one tracking control, so the tracking cycle is 6T plus the settling time of the DAC amplifier. The settling time is negligibly short compared to 6T, so it is shown as 6T in the example in Figure 8.

[0048] As a group shot (tracking control) step (S110), the drawing mechanism 150 performs tracking control, and during the tracking control, each beam of the multi-child beam 20 draws all pixels 36 of the same group in any one of the different sub-irradiation areas 29 located within the irradiation area 34 of the multi-beam 20. In the first multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the first pixel row from the left in each sub-irradiation area 29, which is group 1. The example in Fig. 8 shows a case where, of the beams with beam numbers 0 to 23 aligned in the x direction, beam 23 is used to draw the pixel row of group 1 in a certain sub-irradiation area 29.

[0049] In the tracking reset step (S112), the imaging mechanism 150 resets tracking when one tracking cycle 6T ends, and returns to the previous tracking start position.

[0050] In the determination step (S120), the writing control unit 72 determines whether multiple writing of the target stripe has been completed. If multiple writing of the target stripe has been completed, the process proceeds to the determination step (S130). If multiple writing of the target stripe has not been completed, the process proceeds to the multiple writing process number switching step (S130).

[0051] In the multiple drawing process number switching step (S130), the layer switching processing unit 54 switches the process number of the multiple drawing process in order at each tracking reset (tracking cycle). In other words, the layer switching processing unit 54 switches from the previous stripe layer to the next stripe layer at each tracking reset. In the example of FIG. 8, the first multiple drawing process is switched to the second multiple drawing process. Therefore, the first stripe layer is switched to the second stripe layer.

[0052] In the stripe position Y shift step (S132), the main deflector 208 deflects the beam to shift the position of the irradiation region 34 of the multibeam 20 in the y direction by a predetermined shift amount. When performing multiple drawing with a multiplicity of 4, the position is shifted in the y direction by a shift amount of ¼ the pixel size. Then, the process returns to the group shot (tracking control) step (S110). Thereafter, the steps from the group shot (tracking control) step (S110) to the stripe position Y shift step (S132) are repeated until multiple drawing of the target stripe region 32 is completed. When switching from the first multiple drawing process to the second multiple drawing process, the irradiation region 34 is shifted in the y direction by a shift amount of ¼ the pixel size from the position of the first stripe layer in the first multiple drawing process.

[0053] 8, since the drawing of the first group in the first multiplex drawing process has been completed, the sub-deflector 209 first deflects (shifts) the drawing position of the beam so that the beam will draw the sixth pixel row from the left (first pixel row from the right), which is the first pixel in the sixth group in the next second multiplex drawing process. Here, the drawing position of the beam is aligned with the sixth pixel row from the left and the first pixel row from the bottom.

[0054] Then, while performing tracking control, the drawing mechanism 150 draws all pixels 36 of the same group in each sub-irradiation area 29 in the stripe area 32 of the second stripe layer as a second multiple drawing process. In the second multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the sixth pixel row from the right in each sub-irradiation area 29, which is group 6. The example in Fig. 8 shows a case where, of the beams with beam numbers 0 to 23 aligned in the x direction, beam 22 is used to draw the pixel row of group 6 in the sub-irradiation area 29 irradiated with beam 23.

[0055] Then, the drawing mechanism 150 resets tracking after finishing drawing the second-multiple group 6. The layer switching processing unit 54 switches from the second-multiple drawing process to the third-multiple drawing process. Therefore, it switches from the second stripe layer to the third stripe layer. The main deflector 208 further shifts the position of the irradiation area 34 of the multibeam 20 in the y direction by an amount equal to 1 / 4 of the pixel size through beam deflection. When switching from the second-multiple drawing process to the third-multiple drawing process, the irradiation area 34 is shifted in the y direction by an amount equal to 1 / 4 of the pixel size from the position of the second stripe layer in the second-multiple drawing process. Therefore, when the position of the first stripe layer is used as a reference, the position is shifted by an amount equal to 2 / 4 of the pixel size from the reference position.

[0056] Since drawing of the sixth group in the second multiplex drawing process has been completed, in the next tracking cycle, the sub-deflector 209 first deflects the beam to align (shift) the drawing position so that the beam will draw the fifth pixel row from the left (second from the right), which is the first pixel in the fifth group in the next third multiplex drawing process. Here, the beam drawing position is aligned with the fifth pixel from the left and the first pixel from the bottom.

[0057] Then, while performing tracking control, the drawing mechanism 150 draws all pixels 36 of the same group in each sub-irradiation area 29 in the stripe area 32 of the third stripe layer as a third multiplex drawing process. In the third multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the fifth pixel row from the right in each sub-irradiation area 29, which is group 5. The example in Fig. 9 shows a case where, of the beams with beam numbers 0 to 23 aligned in the x direction, beam 21 draws the pixel row of group 5 in sub-irradiation area 29 irradiated with beams 23 and 22.

[0058] Then, the drawing mechanism 150 resets tracking after finishing drawing the third-multiple group 5. The layer switching processing unit 54 switches from the third-multiple drawing process to the fourth-multiple drawing process. Therefore, it switches from the third stripe layer to the fourth stripe layer. The main deflector 208 further shifts the position of the irradiation area 34 of the multibeam 20 in the y direction by a shift amount of 1 / 4 of the pixel size through beam deflection. When switching from the third-multiple drawing process to the fourth-multiple drawing process, the irradiation area 34 is shifted in the y direction by a shift amount of 1 / 4 of the pixel size from the position of the third stripe layer in the third-multiple drawing process. Therefore, when the position of the first stripe layer is used as a reference, the position is shifted by 3 / 4 of the pixel size from the reference position.

[0059] Since the drawing of the fifth group in the third multiplex drawing process has been completed, in the next tracking cycle, the sub-deflector 209 first deflects the beam to align (shift) the drawing position so that the beam will draw the fourth pixel row from the left (third from the right), which is the first pixel in the fourth group of the next fourth multiplex drawing process. Here, the drawing position of the beam is aligned with the fourth pixel from the left and the first pixel from the bottom.

[0060] Then, while performing tracking control, the drawing mechanism 150 draws all pixels 36 of the same group in each sub-irradiation area 29 in the stripe area 32 of the fourth stripe layer as a fourth multiple drawing process. In the fourth multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the fourth pixel row from the right in each sub-irradiation area 29, which is group 4. The example in Fig. 9 shows a case where, of the beams with beam numbers 0 to 23 aligned in the x direction, beam 20 is used to draw the pixel row of group 4 in the sub-irradiation area 29 irradiated with beams 23, 22, and 21.

[0061] Then, after finishing drawing the fourth multiplex group 4, the drawing mechanism 150 resets tracking. The layer switching processor 54 switches from the fourth multiplex drawing process to the first multiplex drawing process. Therefore, it switches from the fourth stripe layer to the first stripe layer. The main deflector 208 deflects the beam to shift the position of the irradiation area 34 of the multibeam 20 in the -y direction so as to return it to the reference position of the first stripe layer.

[0062] Then, in the first multiplex drawing process, drawing of the next group 2 is performed. In the next tracking cycle, as the second multiplex drawing process, a Y deflection shift is performed and drawing of the next group 1 is performed. In the next tracking cycle, as the third multiplex drawing process, a Y deflection shift is performed and drawing of the next group 6 is performed. In the next tracking cycle, as the fourth multiplex drawing process, a Y deflection shift is performed and drawing of the next group 5 is performed. In the next tracking cycle, a Y deflection shift reset (a shift to return to the reference position) is performed and the process returns to the first multiplex drawing process, and drawing of the next group 3 is performed. Thereafter, drawing of each stripe layer is similarly performed in accordance with the drawing order of the multiple groups for each processing number of the set multiplex drawing process. By repeating this operation, the position of the irradiation region 34 moves sequentially from irradiation regions 34a to 34o as shown in FIG. 4, and the stripe region 32 is drawn.

[0063] In the determination step (S140), the writing control unit 72 determines whether multiple writing has been completed for all stripe regions 32. If multiple writing has been completed for all stripe regions 32, the writing process ends. If multiple writing has not been completed for all stripe regions 32, the XY stage 105 is moved to a position where writing is possible for the next stripe region 32 that has not yet been multiple written, and the process returns to the multiple writing step (S108). The multiple writing step (S108) is then repeated until multiple writing has been completed for all stripe regions 32.

[0064] Fig. 10 shows an example of the beam numbers used to write the sub-irradiation regions in embodiment 1. Fig. 10 shows a portion of the results of writing three sub-irradiation regions 29 arranged in the x direction in accordance with the writing sequences of Figs. 8 and 9. "i" indicates an index. In the ith sub-irradiation region 29 in the x direction, in the first multiplexing drawing process, the first pixel row from the left is drawn with beam 23, the second pixel row with beam 19, the third pixel row with beam 15, the fourth pixel row with beam 11, the fifth pixel row with beam 7, and the sixth pixel row with beam 3. As the multiplicity is thus 4, drawing is performed with each beam shifted by four beams in the x direction. In addition, in the second multiplex drawing process, the first pixel row from the left is drawn with beam 18, the second pixel row with beam 14, the third pixel row with beam 10, the fourth pixel row with beam 6, the fifth pixel row with beam 2, and the sixth pixel row with beam 22. In addition, in the third multiplex drawing process, the first pixel row from the left is drawn with beam 13, the second pixel row with beam 9, the third pixel row with beam 5, the fourth pixel row with beam 1, the fifth pixel row with beam 21, and the sixth pixel row with beam 17. In addition, in the fourth multiplex drawing process, the first pixel row from the left is drawn with beam 8, the second pixel row with beam 4, the third pixel row with beam 0, the fourth pixel row with beam 20, the fifth pixel row with beam 16, and the sixth pixel row with beam 12.

[0065] In each pixel column in the x direction of the (i+1)th sub-irradiation area 29 in the x direction, in the drawing process of the corresponding processing number of the multiple drawing, drawing is performed with a beam that is shifted by one in the x direction from each pixel column in the x direction of the i-th sub-irradiation area 29. In the first multiplex drawing process, the first pixel column from the left is drawn with beam 0, the second pixel column with beam 20, the third pixel column with beam 16, the fourth pixel column with beam 12, the fifth pixel column with beam 8, and the sixth pixel column with beam 4. In addition, in the second multiplex drawing process, the first pixel row from the left is drawn with beam 19, the second pixel row with beam 15, the third pixel row with beam 11, the fourth pixel row with beam 7, the fifth pixel row with beam 3, and the sixth pixel row with beam 23. In addition, in the third multiplex drawing process, the first pixel row from the left is drawn with beam 14, the second pixel row with beam 10, the third pixel row with beam 6, the fourth pixel row with beam 2, the fifth pixel row with beam 22, and the sixth pixel row with beam 18. In addition, in the fourth multiplex drawing process, the first pixel row from the left is drawn with beam 9, the second pixel row with beam 5, the third pixel row with beam 1, the fourth pixel row with beam 21, the fifth pixel row with beam 17, and the sixth pixel row with beam 13.

[0066] Similarly, in the drawing process of the corresponding process number of the multiple drawing, each pixel column in the x direction of the (i+2)th sub-irradiation area 29 in the x direction is drawn with a beam that is shifted by one in the x direction from each pixel column in the x direction of the (i+1)th sub-irradiation area 29. In the first multiplex drawing process, the first pixel row from the left is drawn with beam 1, the second pixel row with beam 21, the third pixel row with beam 17, the fourth pixel row with beam 13, the fifth pixel row with beam 9, and the sixth pixel row with beam 5. In addition, in the second multiplex drawing process, the first pixel row from the left is drawn with beam 20, the second pixel row with beam 16, the third pixel row with beam 12, the fourth pixel row with beam 8, the fifth pixel row with beam 4, and the sixth pixel row with beam 0. In addition, in the third multiplex drawing process, the first pixel row from the left is drawn with beam 15, the second pixel row with beam 11, the third pixel row with beam 7, the fourth pixel row with beam 3, the fifth pixel row with beam 23, and the sixth pixel row with beam 19. In addition, in the fourth multiplex drawing process, the first pixel row from the left is drawn with beam 10, the second pixel row with beam 6, the third pixel row with beam 2, the fourth pixel row with beam 22, the fifth pixel row with beam 18, and the sixth pixel row with beam 14.

[0067] FIG. 11 shows an example of the average beam number of multiple beams that write to each position in the first embodiment and the first comparative example. In FIG. 11, the vertical axis shows the average beam number, and the horizontal axis shows the pixel position in the x direction. In the first comparative example, the writing order of multiple groups is the same in the writing process for each processing number of multiple writing. The rest of the writing sequence is the same as in the first embodiment. As shown in FIG. 11 , the average beam number of pixel columns in the sub-irradiation region 29 drawn with beam 23 in the first drawing process is 22 in Comparative Example 1, but can be set to 16 in Embodiment 1. Furthermore, the average beam number of pixel columns in the sub-irradiation region 29 drawn with beam 19 in the first drawing process is 18 in Comparative Example 1, but can be set to 12 in Embodiment 1. Furthermore, the average beam number of pixel columns in the sub-irradiation region 29 drawn with beam 15 in the first drawing process is 14 in Comparative Example 1, but is set to 8 in Embodiment 1. Furthermore, the average beam number of pixel columns in the sub-irradiation region 29 drawn with beam 11 in the first drawing process is 10 in Comparative Example 1, but is set to 10 in Embodiment 1. Furthermore, the average beam number of pixel columns in the sub-irradiation region 29 drawn with beam 7 in the first drawing process is 6 in Comparative Example 1, but is set to 12 in Embodiment 1. Furthermore, the average beam number of pixel rows in the sub-irradiation region 29 written with beam 3 in the first multiplex writing process is 2 in the first comparative example, whereas it is 14 in the first embodiment.

[0068] As described above, in Comparative Example 1, the average beam number varies from, for example, 2 to 22, whereas in Embodiment 1, it can be kept within the range of, for example, 8 to 16. In other words, in Comparative Example 1, many pixel rows are drawn using only a plurality of beams located in a biased portion of the beam array area. In contrast, in Embodiment 1, drawing is possible using a plurality of beams that are widely distributed over the entire beam array area. The same is true for each of the sub-irradiation areas 29 aligned in the x direction. Therefore, according to the first embodiment, the effect of averaging the positional deviation caused by the distortion of the beam array shape can be improved compared to the first comparative example.

[0069] FIG. 12 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number in the multiple rendering process according to the first embodiment. FIG. 13 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number in the multiple rendering process in Comparative Example 1 of the first embodiment. FIG. 14 shows an example of the relationship between the amount of positional deviation and the pixel position in the rendering process of each processing number in the multiple rendering process in Comparative Example 2 of Embodiment 1. In FIG.

[0070] 12 to 14, the vertical axis represents the amount of misalignment (error), and the horizontal axis represents the pixel position in the x direction. The examples of FIGS. 12 to 14 show the amount of misalignment that occurs at each pixel when the amount of misalignment (error) at the center position of the designed beam array shape is set to zero, and the amount of misalignment at the end in the -x direction is set to -1 and the amount of misalignment at the end in the x direction is set to +1. Also, the examples of FIGS. 12 to 14 show the amount of misalignment at each pixel position in the drawing processes of each process number of the multiple drawing processes, superimposed on each other. Comparative Example 1 shows a case where drawing is performed in the drawing sequence described in Fig. 11. Comparative Example 2 shows a case where the first and second multiplex drawing processes draw each group in the same drawing order, and the third and fourth multiplex drawing processes draw each group in the reverse order of the first and second multiplex drawing processes.

[0071] As shown in FIG. 13, in Comparative Example 1, the amount of positional deviation changes in the same manner in each drawing process of multiple drawing, and therefore it is understood that the amount of positional deviation is not canceled out even when multiple drawing is performed. Furthermore, in Comparative Example 2, as shown in Figure 14, although the positional deviation amounts are offset in some sub-irradiation areas 29, the relationship between the positional deviation amounts gradually shifts in other sub-irradiation areas 29, and the effect of averaging the positional deviation amounts becomes smaller.

[0072] In contrast to this, in the first embodiment shown in FIG. 12, it can be seen that the positional deviation amounts are averaged in all of the sub-irradiation areas 29.

[0073] FIG. 15 shows an example of the relationship between the average error value of the multiple writing process for pixels at the same position in each sub-irradiation region and the pixel position in the first embodiment. FIG. 16 shows an example of the relationship between the average error value of the multiple drawing process for pixels at the same position in each sub-irradiation region and the pixel position in Comparative Example 1 of Embodiment 1. In FIG. FIG. 17 shows an example of the relationship between the average error value of the multiple drawing process for pixels at the same position in each sub-irradiation region and the pixel position in Comparative Example 2 of Embodiment 1. In FIG.

[0074] 15 to 17, the vertical axis indicates the average positional deviation amount (average error value), and the horizontal axis indicates the pixel position in the x direction. The average error value indicates the average value of the error values ​​in the drawing process for each process number when multiple drawing is performed on the pixel. In the examples of FIGS. 15 to 17, the graphs are formed by focusing on the first pixel from the bottom in the first column from the left in each of the sub-irradiation areas 29 aligned in the x direction.

[0075] 16, in Comparative Example 1, as the sub-irradiation areas 29 move away from each other in the x direction, the average error value also shifts to the negative side within the range of -1 to +1, then reverses midway, and then shifts to the positive side within the range of -1 to +1. This indicates that the positional deviation amount of the target pixel has not been averaged. 17, in Comparative Example 2, as the sub-irradiation areas 29 move away from each other in the x direction, the average error value also shifts to the negative side within the range of -1 to +1, then reverses midway, and then shifts to the positive side within the range of -1 to +1. This indicates that the positional deviation amount of the pixel of interest has not been averaged.

[0076] 15, the average error value varies as the distance between the sub-irradiation areas 29 increases in the x direction, but the range is within the range of approximately −0.4 to +0.4. This shows that the effect of averaging the positional deviation amount of the pixel of interest is significant in all sub-irradiation areas 29.

[0077] As described above, it is possible to reduce pattern positional deviation due to distortion of the beam array shape according to Embodiment 1. Furthermore, it is possible to improve the effect of averaging positional deviations at pixel boundaries by shifting the position in the Y direction by less than the pixel size.

[0078] Embodiment 2 In the first embodiment, a configuration for performing multiple writing within the same pass has been described, but the present invention is not limited to this. In the second embodiment, a configuration for performing multiple writing by moving the XY stage 105 through the same stripe region 32 multiple times will be described.

[0079] The configuration of the drawing device 100 in the second embodiment may be the same as that in Fig. 1. In the second embodiment, the contents are the same as those in the first embodiment except for the points that will be particularly explained below.

[0080] Fig. 18 is a flowchart showing an example of main steps of the writing method according to the second embodiment. In Fig. 18, the writing method according to the second embodiment performs a series of steps including a group setting step (S102), a group order setting step (S104), a multiple writing step (S108), and a determination step (S140). The multiple writing step (S108) performs, as internal steps, a stripe writing (tracking control) step (S116), a determination step (S120), a multiple writing process number switching step (S130), and a stripe position Y shift step (S132).

[0081] The group setting step (S102) and the group order setting step (S104) are the same as those in the first embodiment.

[0082] As in the first embodiment, in the multiple drawing step (S108), the drawing data processing unit 70 first generates irradiation time data for each pixel. For example, in a drawing process with a multiplicity of 4, a beam with a dose of, for example, 1 / 4 of the required dose is irradiated onto the target pixel for each drawing process with each process number. The irradiation time data is rearranged in shot order according to a preset drawing sequence. The irradiation time data is stored in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order. Under the control of the drawing control unit 72, the drawing mechanism 150 performs multiple drawing according to the drawing order of the multiple groups for each process number of the set multiple drawing process.

[0083] In the second embodiment, for example, one writing process of the multiple writing processes is performed during one stage movement in a direction parallel to the writing direction. For example, in a writing process with a multiplicity of 4, the stage is moved four times in a direction parallel to the writing direction for one stripe region 32. Also, as in the first embodiment, when performing multiple writing, it is preferable to shift the irradiation region 34 of the multibeam 20 in the y direction perpendicular to the writing direction (x direction) by an amount less than the pixel size for each processing number of the multiple writing process. This will be specifically described below.

[0084] FIG. 19 is a diagram for explaining a part of an example of a multi-beam writing operation according to the second embodiment. FIG. 20 is a diagram for explaining another part of the example of the multi-beam writing operation according to the second embodiment. 19 and 20 show a case where, as in the first embodiment, writing is performed with six different beams in each sub-irradiation region 29 for each stripe layer. The example of FIG. 19 also shows a writing operation in which the XY stage 105 continuously moves at a speed of a distance L corresponding to four beam pitches while writing one group (1 / 6 of the region) in each sub-irradiation region 29. The writing operation shown in the example of FIG. 19 shows a case where, for example, while the XY stage 105 moves the distance L corresponding to one beam pitch, six shots of the multi-beam 20 are performed in a shot cycle T while the irradiation position (pixel 36) is shifted in sequence by the sub-deflector 209, thereby writing (exposing) six different pixels constituting one group in the same sub-irradiation region 29. While these six pixels are being written (exposed), the main deflector 208 deflects the entire multi-beam 20 collectively so that the irradiation area 34 does not shift in position relative to the sample 101 due to the movement of the XY stage 105, thereby causing the irradiation area 34 to follow the movement of the XY stage 105. In other words, tracking control is performed. Since six shots of beam irradiation are performed in one tracking control, the tracking cycle is 6T plus the settling time of the DAC amplifier. Since the settling time is negligibly short compared to 6T, it is shown as 6T in the example of FIG. 19.

[0085] As a stripe drawing (tracking control) step (S116), the drawing mechanism 150 performs tracking control, and during the tracking control, each beam of the multi-child beam 20 draws all pixels 36 of the same group in any one of the different sub-irradiation areas 29 located within the irradiation area 34 of the multi-beam 20. In the first multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the first pixel row from the left in each sub-irradiation area 29, which is group 1. The example in Fig. 19 shows a case where, of the beams with beam numbers 0 to 23 aligned in the x direction, beam 23 is used to draw the pixel row of group 1 in a certain sub-irradiation area 29.

[0086] When one tracking cycle 6T is completed, the drawing mechanism 150 resets tracking and returns to the previous tracking start position. Since drawing of the first group in the first multiplex drawing process is completed, in the next tracking cycle, the sub-deflector 209 first deflects the beam to align (shift) the drawing position of the beam so that it draws the second pixel column from the left, which is the first pixel in group 2 of the next first multiplex drawing process. Here, the drawing position of the beam is aligned with the second pixel from the left and the first pixel from the bottom.

[0087] Then, the drawing mechanism 150 performs the first multiplex drawing of group 2 while performing tracking control. Thereafter, similarly, the drawing is performed in the order of groups 3, 4, 5, and 6 while repeating tracking control and tracking reset. The first multiplex drawing process is performed on the entire stripe region 32 during one movement of the XY stage 105 in the direction parallel to the drawing direction.

[0088] In the determination step (S120), the writing control unit 72 determines whether multiple writing of the target stripe has been completed. If multiple writing of the target stripe has been completed, the process proceeds to the determination step (S130). If multiple writing of the target stripe has not been completed, the process proceeds to the multiple writing process number switching step (S130).

[0089] In the multiple rendering process number switching step (S130), the layer switching processing unit 54 switches the process number of the multiple rendering process in sequence for each stripe rendering. In other words, the layer switching processing unit 54 switches from the previous stripe layer to the next stripe layer for each stripe rendering. In the example of FIG. 19, the first multiple rendering process is switched to the second multiple rendering process. Therefore, the first stripe layer is switched to the second stripe layer.

[0090] In the stripe position Y shift step (S132), the main deflector 208 deflects the beam to shift the position of the irradiation region 34 of the multibeam 20 in the y direction by a predetermined shift amount. When performing multiple drawing with a multiplicity of 4, the position is shifted in the y direction by a shift amount equal to ¼ of the pixel size. Then, the process returns to the stripe drawing (tracking control) step (S116). Thereafter, the steps from the stripe drawing (tracking control) step (S116) to the stripe position Y shift step (S132) are repeated until multiple drawing of the target stripe region 32 is completed. When switching from the first multiple drawing process to the second multiple drawing process, the irradiation region 34 is shifted in the y direction by a shift amount equal to ¼ of the pixel size from the position of the first stripe layer in the first multiple drawing process. Then, drawing is started from the initial position of the target stripe region 32.

[0091] In the second multiplexing drawing process, for example, six pixels 36 are drawn from bottom to top in the sixth pixel row from the left in each sub-irradiation area 29, which is group 6. The example in Fig. 20 shows a case where beam 22, out of the beams with beam numbers 0 to 23 aligned in the x direction, draws the pixel row of group 6 in a certain sub-irradiation area 29.

[0092] When one tracking cycle 6T is completed, the drawing mechanism 150 resets tracking and returns to the previous tracking start position. Since drawing of the sixth group of the second multiplex drawing process is completed, in the next tracking cycle, the sub-deflector 209 first deflects the beam to align (shift) the drawing position of the beam so that it draws the first pixel row from the left, which is the first pixel of group 1 of the next second multiplex drawing process. Here, the drawing position of the beam is aligned with the first pixel from the left and the first pixel from the bottom.

[0093] Then, the drawing mechanism 150 performs the second multiplex drawing of group 1 while performing tracking control. Thereafter, similarly, the drawing is performed in the order of groups 2, 3, 4, and 5 while repeating tracking control and tracking reset. The second multiplex drawing process is performed on the entire stripe region 32 during one movement of the XY stage 105 in the direction parallel to the drawing direction.

[0094] When the second multiplex drawing process is completed, the irradiation area 34 is shifted in the y direction by an amount equal to 1 / 4 of the pixel size from the position of the second stripe layer of the second multiplex drawing process. Then, drawing is started from the initial position of the target stripe area 32.

[0095] In the third multiplex drawing process, tracking control and tracking reset are repeated to perform drawing in the order of groups 5, 6, 1, 2, 3, and 4. During one run of the XY stage 105 in the direction parallel to the drawing direction, the third multiplex drawing process is performed on the entire stripe region 32.

[0096] When the third multiplex drawing process is completed, the irradiation area 34 is shifted in the y direction by an amount equal to 1 / 4 of the pixel size from the position of the second stripe layer of the third multiplex drawing process. Then, drawing is started from the initial position of the target stripe area 32.

[0097] In the fourth multiplex drawing process, tracking control and tracking reset are repeated to perform drawing in the order of groups 4, 5, 6, 1, 2, and 3. During one run of the XY stage 105 in the direction parallel to the drawing direction, the fourth multiplex drawing process is performed on the entire stripe region 32.

[0098] When the rendering process for the fourth multiplex is completed, the process proceeds to a determination step (S140).

[0099] In the determination step (S140), the writing control unit 72 determines whether multiple writing has been completed for all stripe regions 32. If multiple writing has been completed for all stripe regions 32, the writing process ends. If multiple writing has not been completed for all stripe regions 32, the XY stage 105 is moved to a position where writing is possible for the next stripe region 32 that has not yet been multiple written, and the process returns to the multiple writing step (S108). The multiple writing step (S108) is then repeated until multiple writing has been completed for all stripe regions 32.

[0100] By performing the above operations, an example of the beam numbers used to write the sub-irradiation regions in the second embodiment can be the same as in Fig. 10. Therefore, the same effects as in the first embodiment can be obtained.

[0101] Although the embodiments have been described above with reference to specific examples, the present invention is not limited to these specific examples.

[0102] For example, in each of the above-described embodiments, the case where each group is made up of a plurality of pixels 36 has been described, but the present invention is not limited to this. For example, each group may be made up of one pixel 36. In other words, the case may be such that only one pixel 36 is drawn during one tracking control, and then the operation of performing tracking reset is repeated.

[0103] In such a case, the group order setting unit 52 sets the drawing order of the multiple pixels 36 in the multiple sub-illumination areas 29 for each processing number of the multiple drawing process so that the drawing order of the multiple pixels 36 in the multiple sub-illumination areas 29 differs for each processing number of the multiple drawing process.

[0104] Then, the drawing mechanism 150 performs multiple drawing in accordance with the drawing order of the plurality of beam irradiation unit areas within the plurality of pitch cell areas for each processing number of the set multiple drawing process.

[0105] In this case, in the operation according to the first embodiment, for each tracking cycle in which tracking control and tracking reset are repeated, the drawing process of the corresponding processing number of the multiple drawing process is performed, with the processing number being changed in sequence. At this time, during the tracking control in the drawing process of the corresponding processing number, each beam of the multibeam 20 draws the same pixel 36 in any one of the mutually different sub-irradiation areas 29 located within the irradiation area 34 of the multibeam 20. Through this operation, during one stage movement in a direction parallel to the drawing direction, multiple drawing is performed in accordance with the drawing order of the multiple pixels 36 in the multiple sub-irradiation areas 29 for each of the set processing numbers of the multiple drawing process. Furthermore, as in the first embodiment, when switching the processing number of the multiple drawing process, it is preferable to perform the Y-direction shift by an amount less than the pixel size, as described above.

[0106] In the operation according to the second embodiment, multiple writing may be performed by changing the writing order of the plurality of pixels 36 in the sub-irradiation region 29 of the target stripe region 32 for each pass. Also, when switching the processing number of the multiple writing process, it is preferable to perform the Y-direction shift by a size less than the pixel size, as described above, as in the second embodiment.

[0107] Furthermore, the processing functions described in each of the above-mentioned embodiments may be executed by a computer, and a program for causing a computer to execute such processing functions may be stored in a non-transitory, tangible readable recording medium such as a magnetic disk device.

[0108] Although the description of the device configuration, control method, and other parts not directly necessary for the explanation of the present invention have been omitted, the required device configuration and control method can be appropriately selected and used. For example, the description of the control unit configuration that controls the drawing device 100 has been omitted, but it goes without saying that the required control unit configuration can be appropriately selected and used.

[0109] In addition, all multi-charged particle beam lithography apparatuses, multi-charged particle beam lithography methods, and programs that include elements of the present invention and can be appropriately designed and modified by those skilled in the art are included in the scope of the present invention.

Explanation of Signs

[0110] 20 Multi-beam 22 Hole 24 Control electrode 25 Through-hole 26 Opposing electrode 29 Sub-irradiation region 30 Lithography region 32 Strip region 34 Irradiation region 36 Pixel 41 Control circuit 50 Group setting unit 52 Group order setting unit 54 Layer switching processing unit 56 Y-shift processing unit 70 Lithography data processing unit 72 Lithography control unit 74 Transfer processing unit 100 Lithography apparatus 101 Sample 102 Electron column 103 Lithography chamber 105 XY stage 110 Control computer 112 Memory 130 Deflection control circuit 132, 134 DAC amplifier unit 136 Lens control circuit 138 Stage control mechanism 139 Stage position measuring device 140, 142 Storage device 150 Lithography mechanism 160 Control system circuit 200 Electron beam 201 Electron gun 202 Illumination lens 203 Shaping aperture array substrate 204 Blanking aperture array mechanism 205 Reduction Lens 206 Limiting Aperture Substrate 207 Objective Lens 208 Main deflector 209 Sub deflector 210 Mirror 330 Membrane Region

Claims

1. a step of setting a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a writing area of ​​a substrate into a mesh-like shape based on a beam pitch size of the multi-charged particle beam on the substrate; setting a drawing order of the plurality of groups for each processing number of the multiple drawing processes so that the drawing order of the plurality of groups differs for each processing number indicating the processing order of the multiple drawing processes; performing multiple drawing in accordance with the drawing order of the plurality of groups for each processing number of the set multiple drawing process; A multi-charged particle beam writing method comprising:

2. 2. The multi-charged particle beam lithography method according to claim 1, wherein, in performing multiple lithography, a lithography process of a processing number of the multiple lithography process is performed in which a tracking control for making the irradiation area of ​​the multi-charged particle beam follow the movement of the substrate placed on a continuously moving stage and a tracking reset for resetting the position of the irradiation area of ​​the multi-charged particle beam are repeated for each tracking cycle, and while the lithography process of the processing number of the multiple lithography process is performed in order, each beam of the multi-charged particle beam lithography writes all beam irradiation unit areas of the same group in any one of different pitch cell areas located in the irradiation area of ​​the multi-charged particle beam during the tracking control in the lithography process of the processing number, thereby performing multiple lithography in accordance with the set lithography order of the plurality of groups for each processing number of the multiple lithography process during one movement of the stage in a direction parallel to the lithography direction.

3. 3. A multi-charged particle beam drawing method according to claim 1, wherein the drawing order of the plurality of groups is shifted in order for each processing number of the multiple drawing processes.

4. 3. A multi-charged particle beam drawing method according to claim 1, wherein the irradiation area of ​​the multi-charged particle beam is shifted in a direction perpendicular to the drawing direction by a size less than the size of the beam irradiation unit area for each processing number of the multiple drawing process.

5. a function of setting a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a drawing area of ​​a substrate into a mesh-like shape based on the inter-beam pitch size of the multi-charged particle beam on the substrate; a function of setting a drawing order of the plurality of groups for each processing number of the multiple drawing processes so that the drawing order of the plurality of groups differs for each processing number indicating the processing order of the multiple drawing processes; a function of storing in a storage device the drawing order of the plurality of groups for each processing number of the set multiple drawing processing; a function of reading out the drawing order of the plurality of groups for each processing number of the set multiple drawing process from the storage device, and performing multiple drawing in accordance with the drawing order of the plurality of groups for each processing number of the set multiple drawing process; A program that causes a computer to execute the following.

6. a group setting unit that sets a plurality of groups each consisting of a plurality of beam irradiation unit areas within a plurality of pitch cell areas obtained by dividing a writing area of ​​a substrate into a mesh-like shape based on the beam pitch size of the multi-charged particle beam on the substrate; a group order setting unit that sets a drawing order of the plurality of groups for each processing number of the multiple drawing processes so that the drawing order of the plurality of groups differs for each processing number that indicates a processing order of the multiple drawing processes; a drawing control unit that performs multiple drawing in accordance with a drawing order of the plurality of groups for each processing number of the set multiple drawing process; A multi-charged particle beam drawing apparatus comprising:

7. a step of setting a writing order of a plurality of beam irradiation unit areas in a plurality of pitch cell areas obtained by dividing a writing area of ​​a substrate into a mesh shape by a beam pitch size of the multi-charged particle beam on the substrate, for each processing number of the multiple writing processes, such that a writing order of a plurality of beam irradiation unit areas in the plurality of pitch cell areas differs for each processing number indicating a processing order of the multiple writing processes; a step of performing multiple drawing in accordance with a drawing order of a plurality of beam irradiation unit areas in the plurality of pitch cell areas for each set processing number of the multiple drawing process during one stage movement in a direction parallel to a drawing direction, by performing drawing processes of processing numbers whose processing numbers are sequentially changed in each tracking cycle, in which a tracking control for making the irradiation area of ​​the multi-charged particle beam follow the movement of the substrate placed on a continuously moving stage and a tracking reset for resetting the position of the irradiation area of ​​the multi-charged particle beam are repeated, and by performing the drawing processes of the processing numbers whose processing numbers are sequentially changed in each tracking cycle, in which each beam of the multi-charged particle beam draws the same beam irradiation unit area in any one of different pitch cell areas located in the irradiation area of ​​the multi-charged particle beam during the tracking control in the drawing processes of the processing numbers; A multi-charged particle beam writing method comprising:

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