Multi charged particle beam writing method, multi charged particle beam writing apparatus, and storage medium

Abstract

PURPOSE: To provide a drawing device and method capable of expanding an adjustment range of a reduction ratio of a beam array on a sample surface.CONSTITUTION: A multi-charged particle beam writing method according to an aspect of the present invention includes a step of setting a plurality of stripe regions such that a longitudinal direction of each stripe region of the plurality of stripe regions obtained by dividing a writing region of a target object is parallel to a traveling axis of a stage on which the target object is placed, and a step of writing a beam array including a multi-charged particle beam on a target object surface of the target object in a direction of a first scanning axis having an angle of θ (θ≠0, θ<90°) with respect to a traveling axis of the stage while moving the stage in the direction of the traveling axis. And a drawing step of drawing a pattern in each of the stripe regions by scanning in a direction of a second scanning axis linearly independent of the first scanning axis.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a multi-charged particle beam writing method, a multi-charged particle beam writing apparatus, and a program, and more particularly to a writing method in a multi-beam writing 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, the reduction ratio of the beam array composed of multiple beams on the sample surface is changed depending on the required lithography accuracy. For example, increasing the reduction ratio from the reference reduction ratio increases the lithography time but improves lithography accuracy. Conversely, decreasing the reduction ratio decreases the lithography time but reduces lithography accuracy. Conventionally, lithography processing is performed while maintaining a constant beam array rotation angle. However, changing the reduction ratio causes the beam array to rotate on the sample surface, resulting in rotational positional deviation beyond a certain range. Therefore, under the condition that the beam array rotation is invariant, even when the reduction ratio is changed, the adjustment range of the reduction ratio is limited to a range within which the lithography accuracy due to the rotation of the beam array is acceptable. Therefore, there has been a need for an expanded adjustment range of the reduction ratio.

[0005] Here, a technique has been disclosed in which a stripe region of a sample is rotated from the direction of the main axis of a pattern to be written, and writing is performed while scanning multiple beams in the longitudinal direction of the stripe (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6948765 Summary of the Invention [Problem to be solved by the invention]

[0007] One aspect of the present invention provides a writing apparatus and method that allows for an expanded adjustment range of the demagnification ratio of a beam array on a sample surface. [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 dividing the drawing area of ​​the sample into a plurality of stripe areas, and setting the plurality of stripe areas so that the longitudinal direction of each of the stripe areas is parallel to the moving axis of a stage on which the sample is placed; a writing step of scanning a beam array formed by multiple charged particle beams on the sample surface in a first scanning axis direction, which forms an angle with the stage's traveling axis θ (θ≠0, θ<90°), and in a second scanning axis direction, which is linearly independent of the first scanning axis, while moving the stage in the traveling axis direction, to write a pattern in each of the stripe regions; The present invention is characterized by the following features.

[0009] In addition, the drawing area of ​​the sample is divided into a plurality of pixel areas which are irradiation unit areas of each beam of the beam array, During one stage movement for each stripe region, it is preferable that the beam array is scanned in a direction parallel to the direction of the second scanning axis over a distance that is a natural number m times the size of the pixel region divided by a natural number m″ for each predetermined number of shots.

[0010] In addition, tracking control is repeatedly performed so that the irradiation area of ​​the beam array follows the movement of the stage. Scanning of the beam array in a direction parallel to the direction of the second scan axis is preferably performed during tracking reset.

[0011] The angle θ, the size L of the beam array in the beam array arrangement direction, the size a of the pixel region, and the natural numbers m and m′ have the following relationship: m′ L tanθ=m a This is preferable.

[0012] The scanning of the beam array is performed by deflecting the beam of the beam array. The direction of the main axis of the beam deflection is preferably different from the traveling direction of the stage and coincides with the arrangement direction of the beam array.

[0013] A multi-charged particle beam writing apparatus according to one aspect of the present invention comprises: a setting unit that sets a plurality of stripe regions into which the drawing region of the sample is divided so that the longitudinal direction of each of the stripe regions is parallel to the moving axis of a stage on which the sample is placed; a drawing mechanism having a stage, and scanning a beam array formed by multiple charged particle beams on a sample surface of the sample in a first scanning axis direction, which forms an angle with the traveling axis of the stage of θ (θ≠0, θ<90°), and in a second scanning axis direction, which is linearly independent of the first scanning axis, while moving the stage in the traveling axis direction, to draw a pattern in each of the stripe regions; The present invention is characterized by the following features.

[0014] A program to be executed by a computer according to one aspect of the present invention comprises: a function of storing information about the direction of the travel axis of the stage on which the sample is placed in a storage device; a function of reading the direction of the travel axis of the stage from the storage device, and setting the plurality of stripe regions into which the drawing region of the sample is divided so that the longitudinal direction of each of the stripe regions is parallel to the travel axis of the stage on which the sample is placed; a function of scanning a beam array formed by multiple charged particle beams on the sample surface in a first scanning axis direction, which forms an angle with the stage's traveling axis θ (θ≠0, θ<90°), and in a second scanning axis direction, which is linearly independent of the first scanning axis, while traveling the stage in the traveling axis direction, to write a pattern in each of the stripe regions; The present invention is characterized by the following features. [Effects of the Invention]

[0015] According to one aspect of the present invention, the adjustment range of the reduction ratio of the beam array on the sample surface can be expanded. [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. 10 is a conceptual diagram for explaining an example of a writing region and a stripe region in a first comparative example of the first embodiment. [Figure 5] FIG. 2 is a diagram showing an example of a beam array in a standard magnification state according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing an example of a beam array in a state where the reduction ratio is reduced below the reference magnification ratio in the first embodiment; [Figure 7] FIG. 10 is a diagram showing an example of a beam array in a state where the reduction ratio is increased from the reference magnification ratio in the first embodiment. [Figure 8] FIG. 10 is a diagram for explaining an example of a writing method in a second comparative example of the first embodiment. [Figure 9] FIG. 2 is a flowchart showing an example of main steps of the writing method according to the first embodiment. [Figure 10] FIG. 2 is a diagram showing an example of a beam array region according to the first embodiment. [Figure 11] FIG. 3 is a diagram for explaining an appropriate rotation angle in the first embodiment. [Figure 12] FIG. 10 is a conceptual diagram for explaining an example of a drawing operation in the first embodiment; [Figure 13] 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 14] FIG. 2 is a diagram for explaining an example of a multi-beam writing operation according to the first embodiment. [Figure 15] FIG. 2 is a diagram for explaining a writing technique in a positional relationship in which a stripe region is mainly viewed in the first embodiment. [Figure 16] FIG. 2 is a diagram for explaining a drawing technique in a positional relationship in which the beam array is mainly viewed in the first embodiment. [Figure 17] FIG. 2 is a diagram showing an example of how to set the spacing between stripe regions in the first embodiment. [Figure 18]FIG. 10 is a diagram showing another example of how to set the spacing between stripe regions in the first embodiment. [Figure 19] FIG. 10 is a diagram showing another example of how to set the spacing between stripe regions in the first embodiment. [Figure 20] FIG. 2 is a diagram showing an example of a processing region according to the first embodiment. [Figure 21] FIG. 4 is a diagram showing an example of deflection control parameters according to the first embodiment. [Figure 22] FIG. 10 is a diagram showing another example of the drawing operation in the first embodiment. [Figure 23] FIG. 2 is a diagram illustrating an example of a configuration of a deflector according to the first embodiment. [Figure 24] FIG. 4 is a diagram showing another example of the configuration of the deflector according to the first embodiment. [Figure 25] FIG. 4 is a diagram showing another example of the configuration of the deflector according to the first 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. The electron lens barrel 102 contains an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, an air-core coil 214, a limiting aperture substrate 206, multiple electrostatic lenses 212, an objective lens 207, a main deflector 208, a sub-deflector 209, and a detector 216. It is preferable to use, for example, three or more stages of electrostatic lenses as the multiple electrostatic lenses 212.

[0019] A 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 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 stage 105 is also disposed on the stage 105. A mark 106, which can be adjusted to a position flush with the surface of the sample 101, is also disposed on the stage 105. A cross pattern, for example, is preferably used as the mark pattern formed on the surface of the mark 106.

[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, an electrostatic lens control circuit 137, 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 electrostatic lens control circuit 137, 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 a deflection control circuit 130 via a DAC amplifier 134. A lens group including the illumination lens 202, reduction lens 205, and objective lens 207, and the air-core coil 214 are controlled by a lens control circuit 136. A plurality of electrostatic lenses 212 are controlled by an electrostatic lens control circuit 137. The output of the detector 216 is output to the control computer 110 via a detection circuit (not shown).

[0021] The position of the 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 stage 105 based on the principle of laser interferometry.

[0022] The control computer 110 includes a measurement processing unit 50, an appropriate rotation angle calculation unit 52, a rotation angle adjustment processing unit 54, a pixel setting unit 56, a parameter setting unit 58, a stripe setting unit 60, a Y-shift processing unit 62, a writing data processing unit 70, a writing control unit 72, and a transfer processing unit 74. Each of the units, such as the measurement processing unit 50, the appropriate rotation angle calculation unit 52, the rotation angle adjustment processing unit 54, the pixel setting unit 56, the parameter setting unit 58, the stripe setting unit 60, the Y-shift processing unit 62, 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 and output to and from the measurement processing unit 50, appropriate rotation angle calculation unit 52, rotation angle adjustment processing unit 54, pixel setting unit 56, parameter setting unit 58, stripe setting unit 60, Y-shift processing unit 62, drawing data processing unit 70, drawing control unit 72, and transfer processing unit 74, as well as information being calculated, are stored in 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 horizontal (x direction) columns by q vertical (y direction) columns (p, q≧2) at a predetermined arrangement pitch in shaping aperture array substrate 203. The example in FIG. 2 shows a case where holes 22 are formed in 32 horizontal and 32 vertical (x and y directions) columns. The number of holes 22 is not limited to this. For example, holes 22 may be formed in 512 horizontal and 512 vertical columns. Each hole 22 is formed as a rectangle of the same size and shape. Alternatively, holes 22 may be circular and have the same diameter. Multiple beams 20 are formed by portions of electron beam 200 passing 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 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) for applying a deflection voltage to the control electrode 24 for each passage hole 25 is disposed within the blanking aperture array substrate 31, for example, near 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 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 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] 4 is a conceptual diagram illustrating an example of a writing region and a stripe region in Comparative Example 1 of Embodiment 1. In FIG. 4, the x and y axes indicate a writing coordinate system, which indicates a coordinate system of a pattern to be written. The x direction indicates a direction parallel to the traveling direction of stage 105, and the direction perpendicular to the x direction is the y direction. In other words, stage 105 travels parallel to the writing coordinate system. In Comparative Example 1, as shown in Fig. 4, the writing area 30 (bold line) of the sample 101 is virtually divided into a plurality of rectangular stripe regions 32 with a predetermined width in the y direction. The example of Fig. 4 shows a case where the writing area 30 of the sample 101 is divided into a plurality of stripe regions 32 with a width that is substantially the same as the size of the designed beam array region 34 (irradiation area, writing field) on the sample surface that can be irradiated with a single irradiation of the multibeam 20, for example.

[0032] In Comparative Example 1, the stage 105 moves at a constant speed in the -x direction for each stripe region 32, while scanning the multibeams 20 in the x direction over the stripe region 32. In other words, the scanning direction of the beam array formed by the multibeams 20 advances in a direction parallel to the stage travel direction, thereby performing the drawing process. As a result, each stripe region 32 is drawn with the multibeams 20.

[0033] FIG. 5 is a diagram showing an example of a beam array in a standard magnification state according to the first embodiment. FIG. 6 is a diagram showing an example of a beam array in a state where the reduction ratio is reduced from the reference magnification ratio in the first embodiment. FIG. 7 shows an example of a beam array with a reduction ratio higher than the reference magnification in the first embodiment. As described above, reducing the reduction ratio shortens the writing time. Reducing the reduction ratio widens the width of the stripe regions 32, reducing the number of stripe regions covering the writing region 30. This reduces the stage travel distance and the number of turns, thereby shortening the writing time. Conversely, increasing the reduction ratio improves writing accuracy. Increasing the reduction ratio reduces the beam size and increases the number of pixels per unit area, thereby improving writing accuracy. However, if the reduction ratio of the beam array region 34, which has the reference reduction ratio shown in FIG. 5, is changed to meet the required writing accuracy, the beam array region 34 rotates on the sample surface, as shown in FIGS. 6 and 7. Therefore, changing the reduction ratio beyond a certain range results in a shift in the position of the written pattern due to the rotation of the beam array region 34. For this reason, writing has traditionally been performed under the condition that the beam array region 34 is rotation-invariant to prevent pattern shifts due to the rotation of the beam array region 34. Thus, even when the reduction ratio is changed, the adjustment range of the reduction ratio is limited to the reduction ratio within the range where the drawing accuracy due to the rotation of the beam array is allowed. Therefore, there is a need to expand the adjustment range of the reduction ratio.

[0034] FIG. 8 is a diagram illustrating an example of a writing method in Comparative Example 2 of Embodiment 1. Comparative Example 2 in FIG. 8 illustrates a case in which the stripe regions 32 are set obliquely in accordance with the rotation angle of the beam array region 34. In Comparative Example 2, the stripe regions 32 are set so that the longitudinal direction of the stripe regions 32 is parallel to the sides of the rectangle of the beam array region 34. In this case, since it is necessary to cover the entire writing region by combining multiple stripe regions 32, a wasted region outside the writing region is generated within the stripe regions 32. For example, it is estimated that a rotation of 5 mrad will result in a wasted region and a 1% increase in writing time. Furthermore, the coordinate system of the design data (pattern coordinate system) and the coordinate system of the drawing do not match, which makes analysis of drawing errors complicated. Furthermore, the distribution of the stripe boundaries changes, making it difficult to check the device alignment status by writing (for example, measuring the boundary CD).

[0035] Therefore, in the first embodiment, while the coordinate system of the design data (the coordinate system of the pattern) and the coordinate system of the drawing remain the same, drawing is performed using the rotated beam array region 34. A specific description will be given below.

[0036] Fig. 9 is a flowchart showing an example of main steps of the writing method according to Embodiment 1. In Fig. 9, the writing method according to Embodiment 1 carries out a series of steps including a beam array reduction ratio adjusting step (S101), a beam array reduction ratio and rotation angle measuring step (S102), a beam array optimum rotation angle calculating step (S104), a beam array rotation angle adjusting step (S106), a pixel setting step (S108), a deflection control parameter setting step (S110), a stripe region setting step (S120), and a writing step (S130).

[0037] In the beam array reduction ratio adjustment step (S101), under the control of the electrostatic lens control circuit 137, the multiple electrostatic lenses 212 adjust the reduction ratio of the beam array region 34 on the sample surface to a desired reduction ratio. If emphasis is placed on drawing accuracy, the reduction ratio is increased above the reference reduction ratio. If emphasis is placed on throughput, the reduction ratio is decreased below the reference reduction ratio. If the reference reduction ratio is acceptable, the reduction ratio can be adjusted to the reference reduction ratio. Since the adjustment requires three parameters: rotation, focal position, and magnification, it is preferable to use electrostatic lenses with three or more stages when changing the magnification to change the reduction ratio while maintaining the rotation and focal position.

[0038] In the beam array reduction ratio and rotation angle measurement step (S102), the measurement processing unit 50 measures the reduction ratio and rotation angle of the beam array region 34. Specifically, the operation is as follows. First, the writing control unit 72 controls the stage control mechanism 138 to move the stage 105 to a position where the mark 106 can be irradiated with one of the four corner beams located at the four corners of the multi-beam 20. Then, the corner beam is scanned over the mark 106. Secondary electrons emitted from the mark 105 by this scanning are detected by the detector 216. A signal detected by the detector 216 is output to the control computer 110 via a detection circuit (not shown). Similar operations are performed for the other three corner beams.

[0039] FIG. 10 is a diagram showing an example of a beam array area in the first embodiment. Four mark images are detected using four corner beams. The beam array area can be measured by connecting the centers of the four mark images. The rotation angle of the beam array area 34 can be measured by measuring the relative angle of the measured beam array area with an axis (e.g., the x-axis) of the drawing coordinate system. Furthermore, the size of the beam array area 34 can be measured by measuring the distance between each two points of the four mark images. Once the size can be measured, the reduction ratio M2 can be measured (calculated). The example of FIG. 10 shows the beam array area 34 at a reduction ratio M2, which is reduced compared to the reference reduction ratio M1. The example of FIG. 10 also shows the beam array area 34 rotated at a rotation angle θ0. If the measurement result shows that the reduction ratio M2 is not the desired value, the process returns to the beam array reduction ratio adjustment step (S101) and the adjustment is performed again. After the adjustment is performed again, the beam array reduction ratio and rotation angle measurement step (S102) is performed again.

[0040] In the beam array appropriate rotation angle calculation step (S104), the appropriate rotation angle calculation unit 52 calculates an appropriate value for the rotation angle of the beam array region 34 (appropriate rotation angle).

[0041] Fig. 11 is a diagram for explaining the appropriate rotation angle in the first embodiment. In Fig. 11, the arrangement direction of the beam array region 34 is the X and Y directions. In this case, the angle θ (appropriate rotation angle of the beam array region 34) between the arrangement direction of the beam array (here, the X direction) and the longitudinal direction of the stripe region (the x direction), the size L of the beam array in the arrangement direction of the beam array (the X direction), the size a of the pixel region, and the natural numbers m and m' have the relationship shown in the following formula (1). (1) m′·L·tanθ=m·a

[0042] If the relationship satisfying formula (1) is satisfied, and the lower left corner of the beam array region 34 coincides with, for example, the lower end of the stripe region 32, when the beam array region 34 is scanned in the X direction on the sample surface a distance that is a natural number m' times the size L (L·m'), the distance in the Y direction between the lower left corner of the beam array region 34 and the lower end of the stripe region 32 can be a natural number multiple (m·a) of the pixel size. The example in Figure 11 shows the case where m' = 1. As will be described later, in the first embodiment, during writing of each stripe region 32, the beam array region 34 is Y-shifted (Y-deflected) in the -Y direction by a distance that is a natural number multiple of the pixel size (m·a) every time the beam array region 34 is scanned in the X direction by a distance that is a natural number multiple of L (L·m'). This causes the lower left corner of the beam array region 34 to coincide with the bottom end of the stripe region 32. Therefore, the appropriate rotation angle θ can be defined by the following equation (2). (2) θ=tan -1 ((m·a) / (m′·L)

[0043] In the beam array rotation angle adjustment step (S106), under the control of the lens control circuit 136, the air-core coil 214 adjusts the rotation angle of the beam array region 34 on the sample surface so that the measured rotation angle θ0 of the beam array region 34 on the sample surface becomes the calculated appropriate rotation angle θ. The air-core coil 214 can fine-tune to the desired rotation angle (here, the appropriate rotation angle) even if a rotational deviation occurs despite the fact that the magnification (reduction ratio) is adjusted by the multiple electrostatic lenses 212 without changing the rotation. The air-core coil 214 is an example of a beam array rotation angle adjustment coil. As the beam array rotation angle adjustment coil, the air-core coil 214 that does not generate hysteresis is preferable, but is not limited to this. Other electromagnetic lenses or electrostatic lenses may also be used.

[0044] As a result, the main axis of the beam array becomes the X direction, which is one of the arrangement directions of the beam array rotated by the appropriate rotation angle θ on the sample surface, and the Y direction, which is the other arrangement direction of the beam array and is perpendicular to the X direction.

[0045] In the pixel setting step (S108), the pixel setting unit 56 divides the drawing region 30 of the sample 101 into a plurality of pixels (pixel regions) which become unit regions to be irradiated by each beam of the beam array.

[0046] Fig. 12 is a conceptual diagram for explaining an example of the writing operation in embodiment 1. As shown in Fig. 12, the writing region 30 (bold line) on the sample 101 is virtually divided into a plurality of rectangular stripe regions 32 with a predetermined width in the y direction, for example. The example in Fig. 12 shows a case where the writing region 30 on the sample 101 is divided 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 one irradiation of the multibeam 20, for example, in the y direction of the writing coordinate system.

[0047] FIG. 13 is a diagram showing an example of a multi-beam irradiation area and a pixel to be written in the first embodiment. In FIG. 13, a writing area 30 on a sample 101 is divided into a plurality of mesh areas in a mesh shape, for example, based on the beam size of the multi-beam 20. Each mesh area becomes a pixel 36 to be written (beam irradiation unit area, irradiation position). The size of the pixel 36 to be written is not limited to the beam size, and may be any size regardless of the beam size. For example, the pixel may be 1 / n (n is an integer equal to or greater than 1) of the beam size.

[0048] In the first embodiment, when forming pixels 36, the direction of the appropriate rotation angle θ is defined as the X axis, and the direction perpendicular to the X axis is defined as the Y axis, and the drawing area 30 is divided into a plurality of pixels 36 using these X and Y axes as the main axes. In other words, the main axes of the mesh data are the X and Y axes. Therefore, the main axes of the mesh data are not parallel to the traveling direction of the stage 105, which moves parallel to the x direction of the drawing coordinate system. The example in FIG. 13 shows a pixel area of ​​the same size as the Y direction size of the beam array area 34.

[0049] Here, the size of the beam array region 34 in the X direction can be defined by the number of beams in the X direction multiplied by the inter-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 inter-beam pitch in the Y direction. In the example of FIG. 13, for example, a 512×512 array of multi-beams is shown abbreviated to an 8×8 array of multi-beams. A plurality of pixels 28 (beam drawing positions) that can be irradiated with one shot of the multi-beam 20 are shown within the beam array region 34. The pitch between adjacent pixels 28 is the inter-beam pitch of each of the multi-beams. A rectangular region surrounded by the size of the inter-beam pitch in the X and Y directions constitutes one sub-irradiation region 29 (pitch cell region). In the example of FIG. 13, each sub-irradiation region 29 is composed of, for example, 4×4 pixels.

[0050] 14 is a diagram illustrating an example of a multi-beam writing operation in the first embodiment. The example of FIG. 14 shows a case where writing is performed in each sub-irradiation area 29 with four different beams. The example of FIG. 14 also shows a writing operation in which the stage 105 continuously moves at a speed of a distance Dj·sinθ, which is obtained by multiplying a distance Dj corresponding to eight beam pitches by sinθ, while writing is performed on ¼ of the area in each sub-irradiation area 29 (one corresponding to the number of beams used for irradiation). The direction of the main axis of beam deflection that collectively deflects the multi-beams 20 is different from the traveling direction (-x direction) of the stage 105 and coincides with the arrangement direction of the beam array (X and Y directions).

[0051] In the drawing operation shown in the example of FIG. 14 , for example, while the stage 105 moves a distance of Dj·sinθ, the sub-deflector 209 sequentially shifts the irradiation position (pixel 36) while firing four shots of the multi-beam 20 in a shot cycle T to draw (expose) four different pixels in the same sub-irradiation region 29. The irradiation time of the electron beam irradiating each pixel 36 is determined by irradiation time data (described later). The irradiation time of each pixel 36 is set to fit within the shot cycle T. In other words, the shot cycle T is set to match the pixel with the longest irradiation time. While drawing (exposing) these four pixels, the main deflector 208 deflects the entire multi-beam 20 collectively to prevent the beam array region 34 from shifting its relative position to the sample 101 due to the movement of the stage 105, thereby causing the beam array region 34 to follow the movement of the stage 105. In other words, tracking control is performed. When one tracking cycle is completed, tracking is reset and the system returns to the previous tracking start position.

[0052] Note that since the drawing of the first pixel row from the right in each sub-irradiation area 29 has been completed, after a tracking reset, in the next tracking cycle, the sub-deflector 209 first deflects the beam to align (shift) the drawing position so that the beam draws an undrawn pixel row, for example, the second pixel row from the right, in each sub-irradiation area 29. By repeating this operation during drawing of the stripe area 32, the position of the beam array area 34 of the multi-beam 20 moves sequentially as shown in the beam array areas 34a, 34b, 34c, ... 34o shown in the lower diagram of Figure 12, and drawing is performed.

[0053] By the above-mentioned tracking reset, the beam array region 34 is moved by a distance Dj in the X direction on the surface of the sample 101 by beam deflection by the main deflector 208. In other words, by the tracking reset, the beam array is scanned by a distance Dj in the X direction on the surface of the sample 101 with the beam OFF. In this way, the scanning directions of the beam array are the X direction (first scanning direction) at an angle closer to the traveling direction (-x direction) of the stage 105, and the Y direction (second scanning direction) at an angle perpendicular to the X direction and farther from the traveling direction (-x direction) of the stage 105. Scanning in the Y direction refers to the movement of the multibeam 20 performed by beam deflection by the sub-deflector 209 when irradiating the four pixels 36 during each tracking operation described above. In this way, scanning of the beam array is performed by beam deflection of the beam array.

[0054] In the deflection control parameter setting step (S110), the parameter setting unit 58 sets deflection control parameters. Examples of the deflection control parameters include the number Ej of pixels 36 to be irradiated in each sub-irradiation area 29 during each tracking control, the deflection coordinates (Xk, Yk) for moving to the pixels 36 to be irradiated in each sub-irradiation area 29 during each tracking control, the distance Dj by which the beam array area 34 is moved when tracking is reset, and the number of pixels YYj for Y-shift deflection. k indicates the shot number. j indicates the tracking number indicating the number of tracking operations. In the example of FIG. 14, Ej=4, k=1 is (3,0), k=2 is (3,1), k=3 is (3,2), and k=4 is (3,3). YYj is, for example, 1. Here, the coordinates of 16 (=4 × 4) pixels in the sub-irradiation area 29 are represented by 0, 1, 2, 3 in the X direction and 0, 1, 2, 3 in the Y direction.

[0055] In the stripe region setting step (S120), the stripe setting unit 60 (an example of a setting unit) reads the travel direction of the stage 105 from, for example, the storage device 140, and sets multiple stripe regions 32 into which the writing region 30 of the sample 101 is divided, as shown in FIG. 12. The multiple stripe regions 32 are set so that the longitudinal direction of each of the multiple stripe regions 32 is parallel to the travel axis (±x direction) of the stage 105 on which the sample 101 is placed. Specifically, the stripe regions 32 are set so that the longitudinal direction of the stripe regions 32 is parallel to the x direction of the writing coordinate system. The example of FIG. 12 shows a case where multiple stripe regions 32 are set with the same width as the width of the beam array region 34 in the y direction. Information about the travel axis direction of the stage 105 on which the sample 101 is placed, in other words, information about the main axis of writing, is stored in, for example, the storage device 140. The travel direction of the stage 105 is changed for each stripe, from left to right and then right to left, along the travel axis direction. Alternatively, all stripes are set to either left to right or right to left. During writing, it is preferable to keep the rotation angle of the beam array, ie, the rotation angle relative to the +X direction, constant during writing.

[0056] In the writing step (S130), the writing data processing unit 70 first reads writing data from the storage device 140, for example, for each stripe region 32, and calculates, for each pixel 36, an irradiation dose D to be applied to that pixel 36. The irradiation dose D may be calculated, for example, by multiplying a preset reference irradiation dose Dbase by a proximity effect correction irradiation coefficient Dp and a pattern area density ρ. In this way, the irradiation dose D is preferably calculated in proportion to the pattern area density calculated for each pixel 36. Regarding the proximity effect correction irradiation coefficient Dp, the writing region (e.g., the stripe region 32) is virtually divided into a plurality of proximity mesh regions (mesh regions for calculating proximity effect correction) of a predetermined size in a mesh pattern. The size of the proximity mesh region is preferably set to approximately 1 / 10 of the range of influence of the proximity effect, for example, approximately 1 μm. Then, the writing data processing unit 70 reads writing data from the storage device 140, and calculates, for each proximity mesh region, a pattern density ρ' (pattern area density) of the pattern to be arranged within that proximity mesh region.

[0057] Next, a proximity effect correction exposure coefficient Dp for correcting the proximity effect is calculated for each proximity mesh region. Here, the size of the mesh region for calculating the proximity effect correction exposure coefficient Dp does not need to be the same as the size of the mesh region for calculating the pattern density ρ'. Furthermore, the correction model for the proximity effect correction exposure coefficient Dp and its calculation method may be the same as the method used in the conventional single-beam writing method.

[0058] Then, the writing data processing unit 70 calculates, for each pixel 36, the irradiation time t of the electron beam for making the calculated irradiation dose D incident on the pixel 36. The irradiation time t can be calculated by dividing the irradiation dose D by the current density J. In this way, a dose map (actually an irradiation time map) is created in which irradiation time data (shot data) for each pixel 36 is defined.

[0059] When multiple writing is performed, a dose map (actually, an irradiation time map) is created for each of the multiple writing processes. In other words, a dose map (actually, an irradiation time map) is created for each stripe layer. The created irradiation time data is stored in the storage device 142 in shot order. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0060] Under the control of the writing control unit 72, the writing mechanism 150 writes a pattern in each stripe region 32 of the sample 101 using the beam array while scanning the beam array (X direction) that scans the beam array formed by the multibeams 20 on the sample surface of the sample 101 and while moving the stage 105 so that the scanning direction (X direction) of the beam array and the traveling direction (-x direction) of the stage 105 are not parallel during the traveling of the stage 105. In other words, while moving the stage 105 in the traveling axis direction (±x direction), the writing mechanism 150 scans the beam array formed by the multibeams 20 on the sample surface of the sample 101 in the direction of a first scanning axis (±X direction) that forms an angle with the traveling axis of the stage 105 of θ (θ≠0, θ<90°) and in the direction of a second scanning axis (±Y direction) that is linearly independent of the first scanning axis, thereby writing a pattern in each stripe region 32. This will be described in detail below.

[0061] FIG. 15 is a diagram for explaining a writing technique in a positional relationship mainly viewing the stripe region in the first embodiment. FIG. 16 is a diagram for explaining a drawing technique in a positional relationship in which the beam array is mainly viewed in the first embodiment. As shown in FIGS. 15 and 16 , there is an angular misalignment between the arrangement direction of the pixels 36 (the main axis of the mesh data) and the longitudinal direction of the stripe region 32. The main axis of the beam array is also angle-matched to the arrangement direction of the pixels 36. Writing processing is performed in this state. The beam array scans in the X direction of the main axis (X, Y) of the beam array. The stage 105 travels in the −x direction of the main axis (x, y) of writing, which is parallel to the longitudinal direction of the stripe region 32. Therefore, as writing progresses, the position of the beam array (beam array region 34) moves relatively away from the stripe region 32. Therefore, in the first embodiment, during one stage travel over each stripe region 32, the Y-shift processing unit 62 scans the beam array over a distance (m·a) that is a natural number m times the size of the pixel 36, for example, in the −Y direction (a direction parallel to the second scanning direction) for each predetermined number of shots. The predetermined number of shots is set to the number of shots that the beam array (beam array region 34) advances a distance (L·m′) that is a natural number multiple of the size L of the beam array in the X direction. In other words, every time the beam array (beam array region 34) advances a distance (L·m′) that is a natural number multiple of the size L of the beam array in the X direction, the Y-shift processing unit 62 shifts and deflects the beam array (beam array region 34) in the −Y direction by a distance (m·a) that is a natural number multiple of the pixel size a. The example in FIG. 15 shows a case where the beam array (beam array region 34) is deflected in the −Y direction by a distance a (YYj=1) equivalent to one pixel every time the beam array (beam array region 34) advances (scans) a distance of 2L. By repeating this, the stripe region 32 can be drawn, as shown in FIG. 15. If m is 2 or more, the beam array may be deflected in the −Y direction by a distance m·a every time the beam array advances a distance 2L, or the beam array may be deflected in the −Y direction two or more times while the beam array advances (scans) a distance 2L, so that the total deflection amount in the −Y direction is a distance m·a equivalent to m pixels. In normal multi-beam writing where m = 0, that is, the beam array is not rotating, the deflection control parameters are repeated every beam array scanning distance L. When m ≥ 1, that is, when the beam array is rotating, if the angle of equation (2) is set, the deflection control parameters are repeated every distance m' L, but at angles that do not satisfy equation (2), the parameters are repeated at even longer intervals or do not repeat at all, making writing control difficult. When the rotation angle of the beam array is large, m' should be set to a large natural number, i.e., m' = 1. When the rotation angle of the beam array is small, m' should be set to a natural number equal to or greater than 2, i.e., m = 1.

[0062] In this drawing operation, as described above, tracking control is repeatedly performed so that the beam array region 34 follows the movement of the stage 105. Therefore, scanning of the beam array in the -Y direction (Y-shift deflection) is preferably performed during tracking reset. Specifically, it is performed each time a tracking reset is performed multiple times in which the beam array (beam array region 34) advances a distance (L m'). Therefore, it is not necessary to perform Y-shift deflection every time a tracking reset is performed. When L=100 um, m'=1, m=10, and a=10 nm, the rotation angle according to equation (2) is θ=1 mrad.

[0063] In the above example, the rotation angle of the beam array is offset counterclockwise from the longitudinal direction of the stripe region 32. However, this is not limiting. The writing process can be performed in the same way even when the rotation angle of the beam array is offset clockwise from the longitudinal direction of the stripe region 32. In multi-beam writing, multiple writing may be performed by shifting pixels. For example, grids may be arranged in the X and Y directions at the pixel pitch, and writing may be performed so that pixels overlap at a pitch half the pixel size a in both the X and Y directions. This case can be considered as a case where pixels of the same size as the grid are exposed without multiplexing. In other words, the Y-shift processing unit 62 controls the beam array (beam array region 34) to shift and deflect in the -Y direction by a distance (m·b) that is a natural number m' times the writing grid pitch b every time the beam array (beam array region 34) advances a distance (L·m') that is a natural number m' times the size L of the beam array in the X direction. The grid pitch b is not limited to half the pixel size a, but can be set to 1 / m″, a natural number, of the pixel size a. When the grid pitch b is 1 / 1 of the pixel size a, in other words, when the grid pitch b matches the pixel size a, multiple rendering by shifting the pixels is not performed. Therefore, when multiple drawing is performed by shifting the pixels, the beam array is scanned, for example, in the −Y direction (second scanning axis direction) over a distance that is a natural number m times the size of 1 / m″ of the size a of the pixel 36, for each predetermined number of shots during one stage travel for each stripe region.

[0064] Fig. 17 is a diagram showing an example of how to set the spacing between stripe regions in embodiment 1. The example in Fig. 17 shows a case where the stripe regions 32 are set so that the pixels 36 are continuous between adjacent stripe regions 32. However, the present invention is not limited to this.

[0065] FIG. 18 is a diagram showing another example of how to set the spacing between stripe regions in the first embodiment. The example in FIG. 18 shows a case where the stripe regions 32 are set so that, for example, one pixel 36 overlaps between adjacent stripe regions 32. For example, the width of the stripe regions 32 is set to be narrower than the size of the beam array region, for example, by one pixel. In the example in FIG. 18, an unexposed portion appears at the bottom end of the stripe region 32, but it is preferable to write all pixels within each stripe region and on the boundaries between the stripe regions, and to perform multiple writing of pixels on the boundaries of the stripe regions 32 by writing adjacent stripe regions 32. This reduces stitching errors between the stripes.

[0066] FIG. 19 is a diagram showing another example of how to set the spacing between stripe regions in the first embodiment. The example in FIG. 19 shows a case where pixels 36 and stripe regions 32 are set so that the pixels 36 are discontinuously connected between adjacent stripe regions 32. In the above example, the writing region 30 of the sample 101 is first divided into a plurality of pixels 36 in a mesh pattern, but this is not limiting. After the stripe regions 32 are set, a plurality of pixels 36 may be set in a mesh pattern for each stripe region 32. In this case, it is acceptable for the pixels 36 to be discontinuously connected between adjacent stripe regions 32. In such a case, the area ratio of the pattern within the target stripe region 32 within the pixel 36 that overlaps the boundary of the target stripe region 32 may be calculated, and the dose may be set according to this area ratio.

[0067] FIG. 20 is a diagram showing an example of a processing region in the first embodiment. In the above example, data processing of the drawing data is performed in units of stripe regions 32, but this is not limiting. In the example of FIG. 20, the region scanned in the X direction is divided for each Y-shift deflection, and each divided region is defined as one processing region 37. Then, data processing of the drawing data is performed for each processing region 37. For example, rasterization processing is performed. Since the amount of data can be reduced compared to when data processing is performed for an entire stripe region 32, the memory capacity can be reduced. If there is sufficient memory capacity, it is also preferable to increase the length of the region scanned by the beam array in the X direction before Y-shift deflection is performed.

[0068] Fig. 21 is a diagram showing an example of deflection control parameters according to Embodiment 1. In Fig. 21, k represents the shot number, and j represents the tracking number. FIG. 22 is a diagram showing another example of the drawing operation in the first embodiment. The example of FIG. 22 shows how the drawing process is performed in accordance with the deflection control parameters shown in FIG. 21. The examples of FIGS. 21 and 22 show a case where a 4×q beam array (q≧1) in which four beams are arranged in the X direction is used, for example. Here, the drawing sequence of four beam arrays arranged in the X direction at a certain stage in the Y direction out of the 4×q beam array is shown. Also, the case where the beam pitch is 2 beams is shown. In other words, one sub-irradiation area 29 is formed by 2×2 pixels. Also, in the example of FIG. 21, Dj is defined as the number of pixels.

[0069] At k=1 (first shot), the pixel 36 at coordinates (0,0) in each sub-irradiation area 29 is irradiated with the beam corresponding to that sub-irradiation area 29. Since Ej=1, tracking is reset when one pixel is irradiated. Also, since Dj=2, the beam array area 34 advances (scans) by two pixels in the X direction when tracking is reset.

[0070] At k=2 (second shot), the pixel 36 at coordinates (0,1) in each sub-irradiation area 29 at the tracking reset position is irradiated with the beam corresponding to that sub-irradiation area 29. Since Ej=1, tracking is reset when one pixel is irradiated. Also, since Dj=2, the beam array area 34 advances (scans) by two pixels in the X direction when tracking is reset.

[0071] At k=3 (third shot), the pixel 36 at coordinates (1,1) in each sub-irradiation area 29 at the tracking reset position is irradiated with the beam corresponding to that sub-irradiation area 29. Since Ej=1, tracking is reset when one pixel is irradiated. Also, since Dj=2, the beam array area 34 advances (scans) by two pixels in the X direction when tracking is reset.

[0072] At k=4 (fourth shot), the pixel 36 at coordinates (1,0) in each sub-irradiation area 29 at the tracking reset position is irradiated with the beam corresponding to that sub-irradiation area 29. Since Ej=1, tracking is reset when one pixel is irradiated. Also, since Dj=2, the beam array area 34 advances (scans) by two pixels in the X direction when tracking is reset.

[0073] Furthermore, for k=4 (fourth shot), YYj=2, so after the shot, the beam array region 34 is shifted in the Y direction by two pixels in the -Y direction due to beam deflection (Y deflection shift). Furthermore, a change is made to the coordinates (Xk, Yk) in each sub-irradiation region 29 corresponding to the shot of k=5, so deflection in the X direction is also performed in Figure 22.

[0074] At k=5 (fifth shot), tracking is reset, and the same operation as in the case of k=1 is performed within each sub-irradiation area 29 at a position where the Y deflection is shifted.

[0075] At k=6 (sixth shot), the same operation as in the case of k=2 is performed within each sub-irradiation area 29 at the tracking reset position.

[0076] At k=7 (seventh shot), the same operation as in the case of k=3 is performed within each sub-irradiation area 29 at the tracking reset position.

[0077] At k=8 (eighth shot), the same operation as in the case of k=8 is performed within each sub-irradiation area 29 at the tracking reset position.

[0078] Furthermore, at k=8 (8th shot), YYj=2, so after the shot, the beam array region 34 is shifted in the Y direction by two pixels in the -Y direction due to beam deflection (Y deflection shift).

[0079] In this way, the operation of k=1 to 4 is repeated thereafter. Then, the Y deflection shift is repeated every four shots. By performing this operation, writing of each stripe region 32 progresses. Note that the unshot pixels in the portion shown in part A of FIG. 22 are irradiated by the beam array aligned in the X direction adjacent in the -Y direction. Also, the unshot pixels in the portion located at the stripe boundary shown in part B of FIG. 22 are irradiated by the beam array aligned in the X direction in the first row in the Y direction of the beam array in the writing process of the next stripe region 32.

[0080] As a result of the above, each pixel in each stripe region 32 can be written.

[0081] Fig. 23 is a diagram showing an example of the configuration of a deflector in the first embodiment. In the example of Fig. 23, as described in Fig. 1, two stages of deflectors (main deflector 208 and sub-deflector 209) are arranged. In the example of Fig. 23, the main deflector 208 performs tracking control by beam deflection of the entire multi-beam 20 (beam deflection for tracking control), and also performs beam deflection for Y deflection shift (an example of scanning in the Y direction). Furthermore, the sub-deflector 209 performs beam deflection for shifting the shot position within the sub-irradiation region 29 (another example of scanning in the Y direction). However, the present invention is not limited to this.

[0082] Fig. 24 is a diagram showing another example of the configuration of the deflector in the first embodiment. The example of Fig. 24 shows a case where a single-stage deflector (main deflector 208 or sub-deflector 209) is arranged. In this case, the single-stage deflector performs all of the beam deflection for tracking control, the beam deflection for Y deflection shift, and the beam deflection for shifting the shot position within the sub-irradiation region 29.

[0083] Fig. 25 is a diagram showing another example of the configuration of the deflector in the first embodiment. The example of Fig. 25 shows a case where three stages of deflectors (main deflector 208, sub-deflector 209, and an additional deflector) are arranged. In such a case, for example, the first stage deflector (sub-deflector 209) performs beam deflection for shifting the shot position within the sub-irradiation region 29. For example, the second stage deflector (additional deflector) performs tracking control by deflecting the entire multi-beam (beam deflection for tracking control). For example, the third stage deflector (main deflector 208) performs beam deflection for Y deflection shift.

[0084] As described above, the beam deflection for the Y deflection shift and the beam deflection for tracking control may be performed by the same deflector or by different deflectors.

[0085] As described above, according to the first embodiment, it is not necessary to limit the rotation angle of the beam array to a fixed condition, so that the adjustment range of the reduction ratio of the beam array on the surface of the sample 101 can be expanded.

[0086] Furthermore, in the case of Comparative Examples 1 and 2 in which the scanning direction of the beam array is parallel to the longitudinal direction of the stripe region 32 (and the running direction of the stage 105), if there is even one defect beam among the multiple beams 20 constituting the beam array, the position irradiated by the defect beam in the x direction will be repeated. In this case, when a pattern extending along the x direction of the pattern coordinate system is written on the surface of the sample 101, for example, the defect beam may repeatedly write the pattern edge portion at a predetermined cycle, which may cause a problem of deterioration in the shape accuracy of the pattern.

[0087] In contrast, according to the first embodiment, the beam array scans in a direction oblique to the longitudinal direction of the stripe region 32 (and the travel direction of the stage 105), so when writing a pattern extending along the x-direction, the beam irradiating the pattern edge is shifted. Therefore, the pattern edge is not irradiated periodically and repeatedly with the same beam, but with different beams. Therefore, for example, the pattern edge region may be irradiated once with a defect beam, but repeated irradiation with the defect beam can be avoided. This reduces deterioration of pattern accuracy.

[0088] The above describes the embodiments with reference to specific examples. However, the present invention is not limited to these specific examples. When drawing is performed using only a 500 × 500 sub-beam array by omitting a portion of the beam array, for example, six columns on the top, bottom, left, and right of a 512 × 512 array, the present invention can be implemented as a 500 × 500 beam array.

[0089] 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.

[0090] 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.

[0091] In addition, all other multi-charged particle beam writing methods, multi-charged particle beam writing apparatuses, and programs that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included within the scope of the present invention. [Explanation of symbols]

[0092] 20 Multibeam 22 holes 24 control electrode 25 Passing hole 26 Counter electrode 29 Sub-irradiation area 30 drawing area 31 PCB 32 stripe area 33 Support stand 34 Beam Array Area 36 pixels 36 Processing Area 41 Control circuit 50 Measurement processing section 52 Appropriate rotation angle calculation unit 54 Rotation angle adjustment processing unit 56 Pixel setting section 58 Parameter setting section 60 Stripe setting section 62 Y shift processing section 70 Drawing data processing unit 72 Drawing control unit 74 Transfer Processing Unit 100 drawing device 101 Sample 102 Electron Telescope 103 Drawing room 105 XY stage 106 marks 110 Control computer 112 memory 130 Deflection control circuit 132,134 DAC amplifier unit 136 Lens control circuit 137 Electrostatic lens control circuit 138 Stage Control Mechanism 139 Stage Position Measuring Instrument 140,142 Storage device 150 Drawing mechanism 160 Control Circuits 200 electron beam 201 Electron Gun 202 Lighting lens 203 Shaped 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 212 Electrostatic Lens 214 Air-core coil 216 detector 330 Membrane Region

Claims

1. setting a plurality of stripe regions into which a drawing region of a sample is divided so that a longitudinal direction of each of the plurality of stripe regions is parallel to a moving axis of a stage on which the sample is placed; a writing step of scanning a beam array formed by multiple charged particle beams on a sample surface in a first scanning axis direction, which forms an angle with the stage's traveling axis θ (θ≠0, θ<90°), and in a second scanning axis direction, which is linearly independent of the first scanning axis, while the stage is traveling in the traveling axis direction, to write a pattern in each of the stripe regions; A multi-charged particle beam writing method comprising:

2. a drawing area of ​​the sample is divided into a plurality of pixel areas which are irradiation unit areas of each beam of the beam array; 2. The multi-charged particle beam writing method according to claim 1, wherein the beam array is scanned in a direction parallel to the direction of the second scanning axis by a distance that is a natural number m times a size that is 1 / (m") of a size of a pixel region, for each of a predetermined number of shots during one stage travel for each stripe region.

3. a tracking control is repeatedly performed so that the irradiation area of ​​the beam array follows the movement of the stage; 3. The multi-charged particle beam writing method according to claim 2, wherein the scanning of the beam array in the direction parallel to the direction of the second scanning axis is performed during tracking reset.

4. The angle θ, the size L of the beam array in the arrangement direction of the beam array, the size a of the pixel region, and natural numbers m and m′ have the following relationship: m'・L・tanθ=m・a 4. The multi-charged particle beam writing method according to claim 1, wherein the multi-charged particle beam writing method is a multi-charged particle beam writing method.

5. the scanning of the beam array is performed by beam deflection of the beam array; 4. A multi-charged particle beam writing method according to claim 1, wherein the direction of the main axis of the beam deflection is different from the direction of the travel axis of the stage and coincides with the arrangement direction of the beam array.

6. a setting unit that sets a plurality of stripe regions into which a drawing region of a sample is divided so that a longitudinal direction of each of the stripe regions is parallel to a moving axis of a stage on which the sample is placed; a drawing mechanism having the stage, and scanning a beam array formed by multiple charged particle beams on a sample surface of the sample in a first scanning axis direction that forms an angle with the traveling axis of the stage of θ (θ≠0, θ<90°) and in a second scanning axis direction that is linearly independent of the first scanning axis, while moving the stage in the traveling axis direction, to draw a pattern in each of the stripe regions; A multi-charged particle beam drawing apparatus comprising:

7. a function of storing information about the direction of the travel axis of the stage on which the sample is placed in a storage device; a function of reading the direction of the travel axis of the stage from a storage device, and setting the plurality of stripe regions into which the drawing region of the sample is divided so that the longitudinal direction of each of the stripe regions is parallel to the travel axis of the stage on which the sample is placed; a function of scanning a beam array formed by multiple charged particle beams on the sample surface in a first scanning axis direction, which forms an angle with the stage's traveling axis θ (θ≠0, θ<90°), and in a second scanning axis direction, which is linearly independent of the first scanning axis, while traveling the stage in the traveling axis direction, to write a pattern in each of the stripe regions; A program to execute.

Images