Multi-charged particle beam drawing device and multi-charged particle beam drawing method

Abstract

A multi-charged particle beam drawing device according to one embodiment of the present invention is characterized by being provided with: a beam forming mechanism that forms a multi-charged particle beam; and a defect correction data creation circuit that creates defect correction data that defines a dose modulation rate, using a dose distribution that defines, at the same dose, each position of a unit region on the sample surface corresponding to an irradiation region of the entire multi-charged particle beam, regardless of a drawing pattern for drawing. The dose modulation rate is used for distributing and correcting a dose at a position in charge of a defect beam which is always cut off in the multi-charged particle beam to more than one other pixel; a storage device that stores defect correction data; a dose calculation circuit that calculates, for each drawing pattern, individual doses at each position on the sample corresponding to the drawing pattern; and a dose correction circuit that reads out the defect correction data from the storage device for each drawing pattern, corrects individual doses at each position on the sample corresponding to the drawing pattern by means of dose allocation, obtains a corrected dose, and outputs the corrected dose. The dose distribution uses a value obtained by multiplying a dose modulation rate defined in the read defect correction data by an individual dose at each position on the sample; and a drawing mechanism that draws the drawing pattern on the sample using the multi-charged particle beam irradiated at the corrected dose.

Description

Technical Field

[0001] The present application is based on JP2022-090905 (application number) filed in Japan on June 3, 2022, and claims priority to the basic application. All contents described in JP2022-090905 are incorporated herein by reference.

[0002] One embodiment of the present invention relates to a multi-charged particle beam imaging device and a multi-charged particle beam imaging method, for example, to a method of reducing dimensional deviation of a pattern caused by multi-beam imaging. Background Art

[0003] The photolithography technology that is responsible for the progress of miniaturization of semiconductor devices is an extremely important process for generating patterns in the semiconductor manufacturing process. In recent years, with the high integration of LSI, the circuit line width required by semiconductor devices has been miniaturized year by year. Here, electron beam (electron beam) drawing technology has excellent resolution in nature, and uses electron beams to draw mask patterns on mask blanks.

[0004] For example, there is a drawing device using multiple beams. Compared with the case of drawing with a single electron beam, by using multiple beams, more beams can be irradiated at a time, so the productivity can be greatly improved. In such a drawing device using multiple beams, for example, the electron beam emitted from the electron gun is passed through a mask having multiple holes to form multiple beams, and blanking control is performed on each of them. The unblocked beams are reduced by the optical system, thereby reducing the mask image and deflecting it by the deflector, so that it is irradiated to the desired position on the sample.

[0005] In multi-beam drawing, the dose irradiated from each beam is controlled by the irradiation time. However, it is difficult to control the irradiation time due to a failure of a blanking control mechanism, etc., and a defective beam that is a beam that is always cut off and does not irradiate the beam may be generated. In the case where the necessary dose is not irradiated to the sample, there is a problem of generating shape errors in the pattern formed on the sample. In response to this problem, it is proposed to calculate the dose of each pixel corresponding to the drawing pattern to be drawn, and to distribute the insufficient dose in the pixel responsible for the defective beam that is always cut off to the surrounding beams for correction (for example, refer to patent document 1). However, data processing for defective beam correction takes time. Therefore, there may be a problem that data generation cannot keep up with the drawing processing speed.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2019-033117 Summary of the invention

[0009] Technical problem that the invention will solve

[0010] One embodiment of the present invention provides an apparatus and method capable of preventing data processing for defective beam correction from failing to keep up with the speed of drawing processing in multi-beam drawing.

[0011] Means for solving technical problems

[0012] A multi-charged particle beam drawing device according to one aspect of the present invention is characterized by comprising:

[0013] A beam forming mechanism for forming a multi-charged particle beam;

[0014] A defect correction data production circuit produces defect correction data using a dose distribution that defines each position of a unit area on a sample surface corresponding to an irradiation area of ​​the multi-charged particle beam as a whole with the same dose, regardless of a drawing pattern used for drawing, and the defect correction data defines a dose modulation rate that is used to distribute the dose of a position that is responsible for a defective beam that is always beam-cutoff in the multi-charged particle beam to one or more other pixels for correction;

[0015] A storage device storing defect correction data;

[0016] a dose calculation circuit that calculates, for each drawing pattern, a separate dose at each position on the sample corresponding to the drawing pattern;

[0017] a dose correction circuit that reads defect correction data from a storage device for each drawing pattern, corrects the individual dose at each position on the sample corresponding to the drawing pattern by dose allocation, and obtains a corrected dose, wherein the dose allocation uses a value obtained by multiplying the individual dose at each position on the sample by a dose modulation rate defined in the read defect correction data; and

[0018] The drawing mechanism draws the drawing pattern on the sample using the multi-charged particle beam irradiated with the corrected dose.

[0019] A multi-charged particle beam drawing method according to one embodiment of the present invention is characterized by comprising the following steps:

[0020] Formation of multiple charged particle beams,

[0021] Defect correction data is prepared using a dose distribution regardless of a drawing pattern used for drawing, the dose distribution defining each position of a unit area on a sample surface corresponding to an irradiation area of ​​the entire multi-charged particle beam with the same dose, the defect correction data defining a dose modulation rate for allocating the dose of a position responsible for a defective beam that is always beam cutoff in the multi-charged particle beam to one or more other pixels for correction,

[0022] storing the defect correction data in a storage device,

[0023] For each drawing pattern, a separate dose is calculated for each position on the sample corresponding to the drawing pattern.

[0024] For each drawing pattern, defect correction data is read from a storage device, and a separate dose at each position on the sample corresponding to the drawing pattern is corrected by dose allocation to obtain a corrected dose, wherein the dose allocation uses a value obtained by multiplying a dose modulation rate defined in the read defect correction data by a separate dose at each position on the sample,

[0025] A pattern is drawn on the sample using a multi-charged particle beam irradiated at a calibrated dose.

[0026] Effects of the Invention

[0027] According to one aspect of the present invention, in multi-beam drawing, it is possible to avoid a situation where data processing for defective beam correction cannot keep up with the drawing processing speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a conceptual diagram showing the structure of the rendering device according to the first embodiment.

[0029] Figure 2 This is a conceptual diagram showing the structure of the formed aperture array substrate of embodiment 1.

[0030] Figure 3 It is a cross-sectional view showing the structure of the blanking aperture array mechanism according to the first embodiment.

[0031] Figure 4 This is a conceptual diagram for explaining an example of the drawing operation in the first embodiment.

[0032] Figure 5 This is a diagram showing an example of a multi-beam irradiation area and rendering target pixels according to the first embodiment.

[0033] Figure 6 This is a diagram for explaining an example of a multi-beam drawing method according to the first embodiment.

[0034] Figure 7 This is a flowchart showing the main steps of the drawing method according to the first embodiment.

[0035] Fig. 8A This is a diagram for explaining the positional shift of the beam and the periodicity of the positional shift according to the first embodiment.

[0036] Figure 8B This is a diagram for explaining the positional shift of the beam and the periodicity of the positional shift according to the first embodiment.

[0037] Fig. 9A This is a diagram for explaining an example of a positional deviation correction method in the first embodiment.

[0038] Fig. 9B This is a diagram for explaining an example of a positional deviation correction method in the first embodiment.

[0039] Fig.10 This is a diagram showing an example of a dose map of a rectangular unit area for defect correction in the first embodiment.

[0040] Fig.11A This is a diagram for explaining an example of a method of performing defect correction by multi-drawing in the first embodiment.

[0041] Fig. 11B This is a diagram for explaining an example of a method of performing defect correction by multi-drawing in the first embodiment.

[0042] Fig.12 This is a diagram for explaining an example of a method of performing defect correction using peripheral pixels in the first embodiment.

[0043] Fig.13 This is a diagram for explaining another example of the method of performing defect correction using peripheral pixels in the first embodiment. DETAILED DESCRIPTION

[0044] 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 of charged particles such as an ion beam.

[0045] [Implementation Method 1]

[0046] Figure 1 1 is a conceptual diagram showing the structure of the drawing device of Embodiment 1. Figure 1In the drawing device 100, a drawing mechanism 150 and a control system circuit 160 are provided. The drawing device 100 is an example of a multi-charged particle beam drawing device. The drawing mechanism 150 includes an electron lens barrel 102 (multi-electron beam column) and a drawing chamber 103. An electron gun 201, an illumination lens 202, a forming aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a deflector 208 and a deflector 209 are arranged in the electron lens barrel 102. An XY worktable 105 is arranged in the drawing chamber 103. A sample 101 is arranged on the XY worktable 105, and the sample 101 is a mask blank coated with a resist and becomes a drawing object substrate during drawing. The sample 101 includes an exposure mask when manufacturing a semiconductor device or a semiconductor substrate (silicon wafer) for manufacturing a semiconductor device. A reflection mirror 210 for measuring the position of the XY stage 105 is further arranged on the XY stage 105. A Faraday cup 106 is further arranged on the XY stage 105.

[0047] The control system circuit 160 includes a control computer 110, a memory 112, a deflection control circuit 130, digital analog conversion (DAC) amplifier units 132 and 134, a table position detector 139, and storage devices 140, 142, and 144 such as a magnetic disk device. The control computer 110, the memory 112, the deflection control circuit 130, the DAC amplifier units 132 and 134, the table position detector 139, and the storage devices 140, 142, and 144 are connected to each other via a bus not shown. The DAC amplifier units 132 and 134 and the blanking aperture array mechanism 204 are connected to the deflection control circuit 130. The output of the DAC amplifier unit 132 is connected to the deflector 209. The output of the DAC amplifier unit 134 is connected to the deflector 208. The deflector 208 is composed of electrodes of four or more poles, and is controlled by the deflection control circuit 130 via the DAC amplifier 134 for each electrode. The deflector 209 is composed of four or more electrodes, and is controlled by the deflection control circuit 130 for each electrode via the DAC amplifier 132. The stage position detector 139 irradiates the laser beam to the mirror 210 on the XY stage 105, and receives the reflected light from the mirror 210. Then, the position of the XY stage 105 is measured by the principle of laser interference using the information of the reflected light.

[0048] The control computer 110 includes a beam position shift map creation unit 50, a position shift correction data creation unit 52, a detection unit 54, a determination unit 55, a defect correction data creation unit 56, a rasterization unit 60, a dose map creation unit 62, a dose correction unit 64, an irradiation time calculation unit 72, and a drawing control unit 74. Each of the "parts" such as the beam position shift map creation unit 50, the position shift correction data creation unit 52, the detection unit 54, the determination unit 55, the defect correction data creation unit 56, the rasterization unit 60, the dose map creation unit 62, the dose correction unit 64, the irradiation time calculation unit 72, and the drawing control unit 74 has a processing circuit. Such a processing circuit includes, for example, an electrical circuit, a computer, a processor, a circuit substrate, a quantum circuit, or a semiconductor device. Each of the "parts" may use a common processing circuit (the same processing circuit) or may use different processing circuits (separate processing circuits). The information input and output relative to the beam position offset mapping production unit 50, the position offset correction data production unit 52, the detection unit 54, the determination unit 55, the defect correction data production unit 56, the rasterization unit 60, the dose mapping production unit 62, the dose correction unit 64, the irradiation time calculation unit 72 and the drawing control unit 74, as well as the information in the calculation, are each stored in the memory 112.

[0049] In addition, drawing data is input from outside the drawing device 100 and stored in the storage device 140. The drawing data generally defines information of a plurality of graphic patterns used for drawing. Specifically, a graphic code, coordinates, size, etc. are defined for each graphic pattern.

[0050] Here, in Figure 1 , the configuration necessary for explaining the first embodiment is described. The drawing device 100 may generally include other necessary configurations.

[0051] Figure 2 1 is a conceptual diagram showing the structure of a formed aperture array substrate according to Embodiment 1. Figure 2 In the forming aperture array substrate 203, holes (openings) 22 are formed in a matrix with p columns in the longitudinal direction (y direction) and q columns in the transverse direction (x direction) (p, q ≥ 2) at a predetermined arrangement pitch. Figure 2 For example, 512×512 rows of holes 22 are formed in the vertical and horizontal directions (x and y directions). Each hole 22 is formed in a rectangular shape of the same size. Alternatively, it can also be a circle with the same diameter. The forming aperture array substrate 203 (beam forming mechanism) forms the multi-beam 20. Specifically, a part of the electron beam 200 passes through the above-mentioned multiple holes 22 respectively, thereby forming the multi-beam 20. In addition, the arrangement method of the holes 22 is not limited to the following. Figure 2For example, the holes in the kth and k+1th columns in the longitudinal direction (y direction) can be arranged in a grid-like manner. Similarly, the holes in the k+1th and k+2th columns in the longitudinal direction (y direction) can be arranged in a grid-like manner.

[0052] Figure 3 2 is a cross-sectional view showing the structure of the blanking aperture array mechanism of Embodiment 1. Figure 3 As shown, the blanking aperture array mechanism 204 is configured with a semiconductor substrate 31 made of silicon or the like on a support platform 33. The central portion of the substrate 31 is cut, for example, from the back side, and processed into a diaphragm region 330 (first region) of a relatively thin film thickness h. The periphery surrounding the diaphragm region 330 is formed into a peripheral region 332 (second region) of a relatively thick film thickness H. The upper surface of the diaphragm region 330 and the upper surface of the peripheral region 332 are formed to be at the same height position or substantially the same height position. The substrate 31 is held on the support platform 33 at the back of the peripheral region 332. The central portion of the support platform 33 is open, and the position of the diaphragm region 330 is located in the region of the opening of the support platform 33.

[0053] In the diaphragm region 330, Figure 2 The positions corresponding to the holes 22 of the forming aperture array substrate 203 shown are provided with through holes 25 (openings) for passing each beam of the multi-beam 20. In other words, a plurality of through holes 25 for passing each beam corresponding to the multi-beam 20 using electron beams are formed in an array on the diaphragm region 330 of the substrate 31. In addition, a plurality of electrode pairs having two electrodes are arranged at positions opposite to each other across the corresponding through holes 25 among the plurality of through holes 25. Specifically, as Figure 3 As shown, a set of control electrodes 24 and counter electrodes 26 for blanking deflection matching the positions near the respective through holes 25 are arranged on the diaphragm region 330 with the through holes 25 interposed therebetween (blanking device: blanking deflector). In addition, a control circuit 41 (logic circuit) for applying a deflection voltage to the control electrodes 24 for the respective through holes 25 is arranged inside the substrate 31 and near the respective through holes 25 on the diaphragm region 330. The counter electrodes 26 for the respective beams are grounded.

[0054] An amplifier (an example of a switching circuit) not shown in the figure is arranged in the control circuit 41. As an example of an amplifier, a CMOS (Complementary MOS) inverter circuit is arranged. Furthermore, the CMOS inverter circuit is connected to a positive potential (Vdd: blanking potential: first potential) (for example, 5V) (first potential) and a ground potential (GND: second potential). The output line (OUT) of the CMOS inverter circuit is connected to the control electrode 24. On the other hand, the opposing electrode 26 is applied with a ground potential. Furthermore, on the substrate 31, and at positions opposite to the opposing electrodes 26 respectively corresponding to the plurality of opposing electrodes 26 separated by the plurality of through holes 25 respectively corresponding to each other, a plurality of control electrodes 24 capable of switchably applying a blanking potential and a ground potential are arranged.

[0055] As a control signal, either an L (low) potential (e.g., ground potential) lower than the threshold voltage or an H (high) potential (e.g., 1.5 V) higher than the threshold voltage is applied to the input (IN) of the CMOS inverter circuit. In the first embodiment, when the L potential is applied to the input (IN) of the CMOS inverter circuit, the output (OUT) of the CMOS inverter circuit is a positive potential (Vdd), and the electric field generated by the potential difference with the ground potential of the counter electrode 26 deflects the corresponding one of the multi-beams 20, and is blocked by the limiting aperture substrate 206, thereby controlling the beam to be cut off. On the other hand, when the 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 the potential difference with the ground potential of the counter electrode 26 disappears, and the corresponding one of the multi-beams 20 is not deflected, so it is controlled to be beam-on by the limiting aperture substrate 206.

[0056] A corresponding electron beam in the multi-beam 20 passing through each through hole is deflected by a voltage applied to two control electrodes 24 and counter electrodes 26 that are independently paired. Blanking control is performed by this deflection. Specifically, the group of control electrodes 24 and counter electrodes 26 blanks and deflects the corresponding beams of the multi-beam 20 individually by the potential switched by the CMOS inverter circuit that becomes the corresponding switching circuit. In this way, the plurality of blankers perform blanking deflection of the corresponding beams in the multi-beam 20 after passing through the plurality of holes 22 (openings) of the forming aperture array substrate 203.

[0057] Figure 4 1 is a conceptual diagram for explaining an example of a drawing operation in Implementation Example 1. Figure 4As shown, the drawing area 30 of the sample 101 is virtualy divided into a plurality of long strip areas 32 with a predetermined width, for example, in the y direction. First, the XY worktable 105 is moved and adjusted so that the irradiation area 34 that can be irradiated by the emission of the multi-beam 20 once is located at the left end or further to the left of the first strip area 32, and drawing is started. When drawing the first strip area 32, the XY worktable 105 is moved, for example, in the -x direction, and drawing is performed relatively in the x direction. The XY worktable 105 moves continuously, for example, at a constant speed. After the drawing of the first strip area 32 is completed, the worktable position is moved in the -y direction and adjusted so that the irradiation area 34 is relatively located at the right end or further to the right of the second strip area 32 in the y direction. This time, the XY worktable 105 is moved, for example, in the x direction, and drawing is performed in the -x direction in the same manner. By depicting in the x direction in the third strip region 32 and in the -x direction in the fourth strip region 32, the depiction is performed while changing the direction alternately, thereby shortening the depiction time. However, this is not limited to the case where the depiction is performed while changing the direction alternately, and the depiction may be performed in the same direction when depicting each strip region 32. In one emission, multiple emission patterns are formed at one time using multiple beams formed by each hole 22 of the forming aperture array substrate 203, with the maximum number being the same as the number of holes 22 formed in the forming aperture array substrate 203. In addition, in Figure 4 In the example of FIG. 1 , the strip regions 32 are depicted one by one, but the present invention is not limited thereto. Even if multiple depictions are performed to depict the same region multiple times, it is also suitable. When multiple depictions are performed, it is preferred to set the strip regions 32 of each stroke while shifting the positions.

[0058] Figure 5 FIG. 1 is a diagram showing an example of a multi-beam irradiation area and a drawing target pixel according to Embodiment 1. Figure 5 In the strip region 32, for example, a plurality of control grids 27 (design grids) are arranged in a grid pattern with a beam size pitch of the multi-beam 20 on the surface of the sample 101. For example, the control grids 27 are preferably arranged at a pitch of about 10 nm. Such a plurality of control grids 27 are at the designed irradiation position of the multi-beam 20. The arrangement pitch of the control grids 27 is not limited to the beam size, and can be configured with any size that can be controlled as the deflection position of the deflector 209 regardless of the beam size. Furthermore, a plurality of pixels 36 that are virtually divided in a grid pattern with the same size as the arrangement pitch of the control grids 27 as the center are set. Each pixel 36 becomes the irradiation unit area of ​​each beam in the multi-beam. In Figure 5In the example, the case is shown where the drawing area of ​​the sample 101 is divided into a plurality of strip areas 32, for example in the y direction, with a width dimension substantially the same as the dimension of the irradiation area 34 (drawing field) that can be irradiated by irradiation of the multi-beam 20 (beam array) once. The x-direction dimension of the irradiation area 34 can be defined by a value obtained by multiplying the inter-beam spacing in the x-direction of the multi-beam 20 by the number of beams in the x-direction. The y-direction dimension of the irradiation area 34 can be defined by a value obtained by multiplying the inter-beam spacing in the y-direction of the multi-beam 20 by the number of beams in the y-direction. In addition, the width of the strip area 32 is not limited thereto. It is preferably a dimension that is n times (n is an integer greater than 1) the irradiation area 34. In Figure 5 In the example, for example, the illustration of the multi-beam of 512×512 columns is omitted to be shown as a multi-beam of 8×8 columns. Then, a plurality of pixels 28 (beam drawing positions) that can be irradiated by emitting the multi-beam 20 once are shown in the irradiation area 34. In other words, the spacing between adjacent pixels 28 is the spacing between each beam of the multi-beam in design. Figure 5 In the example of , a sub-irradiation area 29 is formed by an area surrounded by the beam spacing. Figure 5 In the example of FIG. 1 , the case where each sub-irradiation region 29 is composed of 4×4 pixels is shown.

[0059] Figure 6 This is a diagram for explaining an example of a multi-beam drawing method according to Embodiment 1. Figure 6 In the figure, it is shown that Figure 5 The beams of the k-th segment of the y-direction coordinates (1, 3), (2, 3), (3, 3), ..., (512, 3) in the multi-beam strip region 32 depict a portion of the secondary irradiation region 29. Figure 6 In the example, for example, 4 pixels are depicted (exposed) while the XY stage 105 moves a distance equal to 8 beam pitches. During the depiction (exposure) of these 4 pixels, the multi-beam 20 is deflected as a whole by the deflector 208 to prevent the relative position of the irradiation area 34 from shifting with respect to the sample 101 due to the movement of the XY stage 105. In this way, the irradiation area 34 follows the movement of the XY stage 105. In other words, tracking control is performed. Figure 6 The example of FIG. 1 shows a case where four pixels are drawn (exposed) during movement of a distance corresponding to eight beam pitches, thereby implementing one tracking cycle.

[0060] Specifically, in each shot, the beam is irradiated within the set maximum drawing time and within the drawing time corresponding to each control grid 27. Specifically, the beam corresponding to each of the turned-on beams in the multi-beam 20 is irradiated to each control grid 27. And, according to each shot cycle time Ttr obtained by adding the stabilization time of the DAC amplifier to the maximum drawing time, the irradiation position of each beam is moved to the next shot position by collective deflection of the deflector 209.

[0061] And, in Figure 6 In the example of FIG. 1 , at the time when the fourth transmission is completed, the DAC amplifier unit 134 resets the beam deflection for tracking control. Thus, the tracking position is returned to the tracking start position at which the tracking control is started.

[0062] In addition, the depiction of the first pixel column from the right of each secondary irradiation area 29 is completed. Therefore, after the tracking is reset, in the next tracking cycle, first, the deflector 209 is deflected to make the depiction positions of the beams corresponding to the control grids 27 of the first section from the bottom and the second pixel from the right of each secondary irradiation area 29 consistent (shifted). By repeating this action, all pixels are depicted. In the case where the secondary irradiation area 29 is composed of n×n pixels, different beams are used to depict every n pixels in n tracking actions. Thus, all pixels within an area of ​​1 n×n pixels are depicted. For other n×n pixel areas within the irradiation area of ​​the multi-beam, the same action is performed at the same time and depiction is performed in the same manner.

[0063] Next, the operation of the drawing mechanism 150 in the drawing device 100 is described. The electron beam 200 emitted from the electron gun 201 (emission source) illuminates the entire forming aperture array substrate 203 through the illumination lens 202. A plurality of rectangular holes 22 (openings) are formed in the forming aperture array substrate 203. And the electron beam 200 illuminates the area including all the plurality of holes 22. Each portion of the electron beam 200 irradiated to the position of the plurality of holes 22 passes through the plurality of holes 22 of such a forming aperture array substrate 203. Thus, for example, a plurality of electron beams (multiple beams 20) in a rectangular shape are formed. Such multi-beams 20 pass through the corresponding blankers (first deflector: separate blanking mechanism) of the blanking aperture array mechanism 204. Such blankers deflect the electron beams that pass through individually (perform blanking deflection).

[0064] The multi-beam 20 after passing through the blanking aperture array mechanism 204 is reduced by the reduction lens 205 and travels toward the hole formed in the center of the limiting aperture substrate 206. Here, the position of the electron beam deflected by the blanker of the blanking aperture array mechanism 204 in the multi-beam 20 deviates from the hole in the center of the limiting aperture substrate 206 and is blocked by the limiting aperture substrate 206. On the other hand, the electron beam not deflected by the blanker of the blanking aperture array mechanism 204 is as shown in FIG. Figure 1 As shown in FIG. 4 , the plurality of beams 20 are formed by passing through the hole in the center of the limiting aperture substrate 206. By turning on / off the individual blanking mechanism 47, blanking control is performed to control the turning on / off of the beam. In this way, the limiting aperture substrate 206 blocks each beam deflected by the individual blanking mechanism 47 to a beam-off state. Then, for each beam, a beam formed from the beam-on state to the beam-off state after passing through the limiting aperture substrate 206 is used to form a beam emitted once. The multi-beam 20 after passing through the limiting aperture substrate 206 is focused by the objective lens 207 to form a pattern image of a desired reduction ratio. The beams (the entire multi-beam 20) after passing through the limiting aperture substrate 206 are deflected in the same direction by the deflectors 208 and 209, and irradiated to each irradiation position on the sample 101 of each beam. The multiple beams 20 for one irradiation are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the multiple holes 22 of the aperture array substrate 203 by the above-mentioned desired reduction ratio.

[0065] As described above, defective beams may be generated in the multi-beams. Defective beams include overdose defective beams where the dose of the beam cannot be controlled and the dose of the beam cannot be controlled. Overdose defective beams include a part of an on defective beam where the dose is always on and a part of a poorly controlled defective beam where the irradiation time is poorly controlled. The insufficient dose defective beam includes a cutoff defective beam where the dose is always off and the remaining part of the poorly controlled defective beam.

[0066] In the case where the sample is not irradiated with the predetermined dose due to a defective beam, there is a problem of generating a shape error of the pattern formed on the sample. To address this problem, in the past, the dose of each pixel corresponding to the desired drawing pattern was calculated. Then, for the dose of each pixel, the excess or insufficient dose in the pixel for which the defective beam is responsible is calculated. Then, the distribution rate for distributing the obtained excess or insufficient dose to the surrounding beams is calculated. Then, the dose of each pixel is modulated according to the distribution rate. This correction method has been studied. However, data processing for defective beam correction takes time. Therefore, there may be a problem that data generation cannot keep up with the drawing processing speed. In addition, if the drawing pattern that is the object of drawing changes, in order to calculate the distribution rate for distributing to the surrounding beams, it is necessary to start over from the point where the dose of each pixel corresponding to the drawing pattern is calculated. In this way, every time the drawing pattern changes, in order to calculate the distribution rate for distributing to the surrounding beams, data processing needs to be re-performed from the beginning.

[0067] Here, in defect beams other than the defect beams that are always cut off, if the designed dose corresponding to the drawing pattern is not determined, it is unclear whether the dose is insufficient or excessive. In the case of correcting the excess dose, the dose of the peripheral beams will be reduced. Therefore, if it is a pixel without a pattern and the designed dose is zero, it cannot be further reduced and therefore cannot be used for defect correction. Therefore, it is difficult to calculate the allocation rate for the peripheral beam distribution without using the drawing pattern. In contrast, for the defect beams that are always cut off in the defect beams, the irradiated dose is zero, so in the case of defect correction, the dose of the peripheral beams will be increased. Therefore, even pixels without a pattern and the designed dose is zero can be used for defect correction. Therefore, the allocation rate for the peripheral beam distribution can be calculated independently regardless of the drawing pattern.

[0068] Therefore, in the first embodiment, for the beam that is always cut off among the defective beams, the distribution rate for distributing the insufficient dose to the surrounding beams regardless of the drawing pattern is calculated as a pre-processing before starting the drawing process. Then, defect correction data defining the distribution rate for each distribution destination of each pixel is prepared in advance. Then, in the actual drawing process, for each drawing pattern, the defect correction data that is not dependent on the prepared drawing pattern is used to modulate the dose of each pixel. This is described in detail below.

[0069] Figure 7 1 is a flowchart showing the main steps of the drawing method in Embodiment 1. Figure 7In the drawing method in the first embodiment, a series of steps including a beam position deviation amount measuring step (S102), a defect beam detecting step (S104), a position deviation correction data creating step (S106), a defect beam position determining step (S108), a defect correction data creating step (S110), a dose calculating step (S120), a dose correcting step (S130), an irradiation time calculating step (S140), and a drawing step (S142) are implemented. In the first embodiment, a case where beam position deviation correction is performed in addition to defect beam correction is described, but the present invention is not limited thereto. In the case where beam position deviation correction is not performed, the beam position deviation amount measuring step (S102) and the position deviation correction data creating step (S106) may be omitted.

[0070] Each of the steps of beam position deviation measuring step (S102), defective beam detecting step (S104), position deviation correction data creating step (S106), defective beam position determining step (S108), and defect correction data creating step (S110) is performed as pre-processing before starting the drawing process.

[0071] In the beam position deviation amount measuring step ( S102 ), the imaging device 100 measures the amount of deviation of the irradiation position on the surface of the sample 101 of each beam of the multi-beam 20 from the corresponding control grid 27 .

[0072] Fig. 8A and Figure 8B 1 is a diagram for explaining the positional offset and periodicity of the positional offset of the beam according to Embodiment 1. Fig. 8AAs shown, due to the characteristics of the optical system, deformation occurs in the exposure field. Due to such deformation, the actual irradiation position 39 of each beam is offset from the irradiation position 37 when irradiating the ideal grid. Therefore, in Embodiment 1, the positional offset of the actual irradiation position 39 of each beam is measured. Specifically, the position of the resist pattern generated by irradiating the multi-beam 20 to the evaluation substrate coated with the resist and developing the evaluation substrate is measured by a position measuring device. Thus, the positional offset of each beam is measured. In the emission size of each beam, if it is difficult to measure the size of the resist pattern at the irradiation position of each beam by the position measuring device, a graphic pattern (for example, a rectangular pattern) of a size that can be measured by the position measuring device is drawn by each beam. Then, the edge positions of both sides of the graphic pattern (resist pattern) (the left and right sides of the rectangular pattern or the upper limit sides) are measured, and the positional offset of the target beam is measured based on the difference between the middle position between the two edges and the middle position of the designed graphic pattern. Then, the obtained positional offset data of the irradiation position of each beam is input to the drawing device 100 and stored in the storage device 144. In addition, in the multi-beam drawing, the drawing is performed while shifting the irradiation area 34 in the strip area 32. Therefore, for example, in Figure 6 In the order of drawing described in Figure 4 As shown in the lower part of FIG, in the depiction of the strip area 32, the position of the irradiation area 34 moves in sequence in the case of the irradiation areas 34a to 34o. And, every time the irradiation area 34 moves, the position shift of each beam is periodic. Alternatively, if the depiction order is such that each beam irradiates all pixels 36 in the corresponding sub-irradiation area 29, then Figure 8B As shown, the positional offset of each beam is periodic in each unit area 35 (35a, 35b, ...) of at least the same size as the irradiation area 34. Therefore, if the positional offset of each beam in the irradiation area 34 of the beam array is measured, the measurement result can be used. In other words, for each beam, it is sufficient to measure the positional offset in each pixel 36 in the corresponding sub-irradiation area 29.

[0073] Then, the beam position offset map making unit 50 first makes a beam position offset map (1) that defines the beam array unit, in other words, the position offset of each beam of each pixel 36 within a rectangular unit area 35 (an example of a unit area) on the sample surface corresponding to the irradiation area 34. The rectangular unit area 35 is an area on the sample surface that corresponds to the irradiation area 34 of the multi-beam 20 obtained by combining each beam of the multi-beam 20 with each designed sub-irradiation area 29 (small area) surrounded by other adjacent beams. Here, the multi-beams 20 are arranged in a square grid, so that the unit area is rectangular, but the shape of the unit area can also be changed according to the arrangement shape of the multi-beams 20. Specifically, the beam position offset map making unit 50 only needs to read the position offset data of the irradiation position of each beam from the storage device 144 and use the data as the mapping value to make the beam position offset map (1). For example, Figure 6 As described in the drawing order, which beam in the multi-beam 20 as a whole irradiates the control grid 27 of each pixel 36 in a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34 irradiated by the multi-beam 20 as a whole is determined according to the drawing order. Thus, the beam position offset map preparation unit 50 determines the beam responsible for irradiating the control grid 27 for each control grid 27 of each pixel 36 in one unit area 35 according to the drawing order, and calculates the position offset of the beam. The prepared beam position offset map (1) is stored in the storage device 144.

[0074] As a defective beam detection process (S104), the detection unit 54 detects defective beams from the multi-beams 20. In the always-on defective beam, the beam of the maximum irradiation time in one shot is always irradiated regardless of the controlled dose. Alternatively, the irradiation is continued even when moving between pixels. In addition, in the always-off defective beam, the beam is always off regardless of the controlled dose. Specifically, under the control of the drawing control unit 74, the drawing mechanism 150 controls the multi-beams 20 one by one to be beam-on through the blanking aperture array mechanism 204, and controls all the remaining beams to be beam-off. In this state, the beam in which no current is detected by the Faraday cup 106 is detected as a cut-off defective beam. Conversely, the control is switched from this state so that the detection target beam becomes beam-off. At this time, although the beam is switched from beam-on to beam-off, the beam in which the current is always detected by the Faraday cup 106 is detected as an open defective beam. After switching from beam on to beam off, the beam in which the current is detected by the Faraday cup 106 for a predetermined period is detected as a control failure defective beam. If all beams of the multi-beam 20 are sequentially checked by the same method, the presence and type of defective beams and the position of the defective beams can be detected. Here, the case where defective beams other than the cut-off defective beam are also detected is described, but only the cut-off defective beam that is always cut off may be detected. The information of the detected defective beams is stored in the storage device 144.

[0075] In the positional deviation correction data creating step ( S106 ), the positional deviation correction data creating unit 52 creates positional deviation correction data for correcting individual positional deviations of the irradiation positions of the multi-beam 20 .

[0076] Fig. 9A and Fig. 9B FIG. 1 is a diagram for explaining an example of a positional offset correction method in Embodiment 1. Fig. 9A In the example of FIG. 1 , a beam a' irradiated to a pixel at coordinates (x, y) is shown as being positionally offset on the -x and -y sides. In order to convert the positional offset of the pattern formed by the beam a' that produces such a positional offset into Fig. 9B In this way, correction can be performed by correcting the position to match the pixel of the coordinates (x, y) and allocating the irradiation amount of the offset amount to the pixels on the opposite side of the offset surrounding pixels. Fig. 9A In the example of , the irradiation amount of the amount shifted toward the pixel at coordinates (x, y-1) is allocated to the pixel at coordinates (x, y+1). The irradiation amount of the amount shifted toward the pixel at coordinates (x-1, y) is allocated to the pixel at coordinates (x+1, y). The irradiation amount of the amount shifted toward the pixel at coordinates (x-1, y-1) is allocated to the pixel at coordinates (x+1, y+1).

[0077] In the first embodiment, the position shift correction allocation amount of the beam allocation irradiation amount to at least one surrounding pixel is calculated in proportion to the position shift amount of the beam. The position shift correction data generating unit 52 calculates the modulation rate of the beam to the pixel and the modulation rate of the beam to at least one surrounding pixel of the pixel according to the ratio of the area shifted by the position shift of the beam to the pixel. Specifically, for each surrounding pixel where the beam is shifted from the target pixel and a part of the beam overlaps, the ratio of the area of ​​the shift amount (the area of ​​the overlapping beam part) divided by the beam area is calculated as the allocation amount (modulation rate of the beam) to the pixel located on the opposite side of the overlapping pixel relative to the target pixel.

[0078] exist Fig. 9A In the example, the area ratio of the pixel offset to the coordinate (x, y-1) can be calculated by (x-direction beam size-(-x)-direction offset)×y-direction offset / (x-direction beam size×y-direction beam size). Therefore, the allocation amount (beam modulation rate) V for the pixel allocation to the coordinate (x, y+1) for correction can be calculated by (x-direction beam size-(-x)-direction offset)×y-direction offset / (x-direction beam size×y-direction beam size).

[0079] exist Fig. 9A In the example of , the area ratio of the pixel shifted to the coordinate (x-1, y-1) can be calculated by -x direction shift amount × -y direction shift amount / (x direction beam size × y direction beam size). Therefore, the allocation amount (beam modulation rate) W for the pixel allocation to the coordinate (x+1, y+1) for correction can be calculated by -x direction shift amount × -y direction shift amount / (x direction beam size × y direction beam size).

[0080] exist Fig. 9A In the example of , the area ratio of the pixel offset to the coordinate (x-1, y) can be calculated by -x direction offset × (y direction beam size - (-y) direction offset) / (x direction beam size × y direction beam size). Therefore, the allocation amount (beam modulation rate) Z used for allocation to the pixel of the coordinate (x+1, y) for correction can be calculated by -x direction offset × (y direction beam size - (-y) direction offset) / (x direction beam size × y direction beam size).

[0081] As a result, the modulation rate U of the beam of the pixel at the coordinates (x, y), which is the amount remaining without being distributed, can be obtained by the calculation of 1-VWZ.

[0082] As described above, for each pixel 36 in the beam array unit, in other words, a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, the modulation rate of the beam to the pixel and the modulation rate of the beam to at least one surrounding pixel that is the distribution destination are calculated. Then, the position shift correction data generating unit 52 generates position shift correction data defining the modulation rate of the beam to the pixel and the modulation rate of the beam to at least one surrounding pixel that is the distribution destination for each pixel 36. The position shift correction data is generated for a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, and the generated position shift correction data is stored in the storage device 144.

[0083] As a defective beam position determination step (S108), the determination unit 55 determines the pixel irradiated by the defective beam that is always cut off in the defective beam for each pixel 36 in a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34 in the beam array unit, in other words. As described above, the control grid 27 determines which beam irradiates each pixel 36 in the rectangular unit area 35 according to the drawing order.

[0084] As a defect correction data production process (S110), the defect correction data production unit 56 uses the dose distribution of each pixel 36 of a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, which is defined by the beam array unit with the same dose, regardless of the drawing pattern used for drawing, to produce defect correction data. The defect correction data defines a dose modulation rate for allocating the dose of the position responsible for the defective beam that is always beam cutoff in the multi-beam 20 to one or more other pixels for correction.

[0085] Fig.10 FIG. 4 is a diagram showing an example of dose mapping of a rectangular unit area for defect correction in Embodiment 1. Fig.10 As shown, it is preferable to use a dose of 100% relative to the reference dose as the dose of each pixel. In other words, it is assumed that the entire rectangular unit area 35 is a so-called solid pattern. The entire rectangular unit area 35 is a so-called solid pattern, and therefore does not depend on the actual drawing pattern.

[0086] exist Figure 6In the example of , the XY stage 105 moves in the -x direction by 32 beam pitches (= 4 times × 8 beam pitches) through 4 tracking actions. One drawing process is performed during the movement of 32 beam pitches. In this configuration, when the beam array unit, in other words, a rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, is drawn using a 512×512 multi-beam unit, multiple drawing (multiplicity = 16) based on 16 (= 512 / 32) drawing processes (passes) is performed on each pixel 36. When the 32×32 multi-beam 20 is drawn, one drawing process (pass) is performed on each pixel. In addition, if the XY stage 105 is repeatedly moved continuously, for example 4 times, multiple drawing (multiplicity = 4) based on 4 drawing processes (passes) is performed on each pixel 36. In addition, in Embodiment 1, the number of stage movements rather than each drawing process of multiple drawing is expressed as a pass.

[0087] Fig.11A and Fig. 11B FIG. 1 is a diagram for explaining an example of a method for performing defect correction by multiple drawing in Embodiment 1. Fig.11A and Fig. 11B In the example of FIG. 1 , a case of performing multiple drawing based on four drawing processes (strokes) is shown. In each pixel, for example, four different beams are irradiated. The dose T(x) to such a pixel is irradiated at 1 / 4 of a second in each stroke. Thus, in pixels not caused by the defective beam, Fig.11A The dose per irradiation is T(x) / pass. In the pixel that the defective beam is responsible for, the defective beam is responsible for one of the four irradiations. In the pass that the defective beam is responsible for, since the beam is not irradiated, the dose for one pass will be insufficient. Therefore, in the case where the pattern is drawn on the sample by multiple drawing, the defect correction data preparation unit 56 prepares the defect correction data in such a way that the correction of the dose of the position that the defective beam is responsible for, which is performed in one of the multiple passes of the multiple drawing, is performed in the other passes. For example, Fig. 11B As shown, defect correction data is prepared so that the distribution dose (shortage) obtained by dividing the dose of one time by the number of other strokes is evenly added to the other strokes. Fig. 11B In the example, 33% of the 25% dose is allocated each time. The allocation method is not limited to the equal case. It is also possible to allocate with emphasis on a part of the stroke. If the allocation is emphasized, there is a case where the dose becomes too large in a part of the stroke. In this case, the maximum irradiation time becomes longer, resulting in an increase in the drawing time. Therefore, it is preferable to add it evenly to other strokes. In this way, the maximum irradiation time can be suppressed from increasing.

[0088] The defect correction data defines the dose modulation rate of 0% for the pixel that the defective beam is responsible for and the dose modulation rate for at least one of the passes that are the distribution destinations. For other pixels, a dose modulation rate of 100% is defined as solid data. The defect correction data is preferably prepared for each pass. The information of the pixel that the defective beam is responsible for is shared between each pass.

[0089] In addition, as described above, when creating the positional offset correction data, the defect correction data creating unit 56 inputs the positional offset correction data for correcting the individual positional offsets of each irradiation position of the multi-beam, and creates the defect correction data using the positional offset correction data. Thus, for the pixel that the defective beam is responsible for, the dose modulation rate of the own 0% and the dose modulation rate to at least one stroke that is the distribution destination are defined. For the dose modulation rate to the stroke to the distribution destination, a value obtained by multiplying each dose modulation rate defined in the positional offset correction data is further defined. For the other pixels, a dose modulation rate of each dose modulation rate defined in the positional offset correction data × 100% is defined.

[0090] The defect correction is not limited to the case where the defect correction is performed by allocation to other strokes. For example, the defect correction data generating unit 56 generates defect correction data so as to correct the dose of the position that the defect beam is responsible for by the peripheral beam, and the peripheral beam is used to irradiate the position around the position that the defect beam is responsible for.

[0091] Fig.12 1 is a diagram for explaining an example of a method for performing defect correction using peripheral pixels in Embodiment 1. The defect correction data generating unit 56 allocates the dose of the position that the defect beam is responsible for to at least one, for example, three or more peripheral pixels around the control grid 10 of the pixel that the defect beam is responsible for. Fig.12 In the example, the peripheral pixels allocated to irradiation position 39a, the peripheral pixels allocated to irradiation position 39c, and the peripheral pixels allocated to irradiation position 39g are shown. It is preferred to use three or more irradiation positions that surround the control grid 10 of the pixels responsible for the defective beam. In embodiment 1, it is preferred to determine the allocation rate in such a way that the center of gravity position of the multiple allocation rates (dose modulation rates) allocated becomes the position of the control grid 10 of the pixels responsible for the defective beam. In this case, the allocation rate is determined according to the distance ri from the control grid 10 to the irradiation position of the peripheral beam. i represents the index of the peripheral beam that is the object in the N peripheral beam groups. In this case, each allocation rate δdi can be defined by, for example, the following formula (1) using 100% dose Δ and distance ri.

[0092] [Formula 1]

[0093] (1)

[0094] like Fig.12 As shown, it is also possible that the irradiation position 39g of the distribution destination is outside the pattern. When a dose distribution corresponding to the drawing pattern is prepared in advance, it is known whether the irradiation position of each pixel is inside or outside the pattern. Therefore, for the pixels located at the irradiation position outside the pattern, since the dose corresponding to the drawing pattern is zero, the following adjustment can be made, that is, increasing the dose allocated for defect correction. If the offset of the center of gravity position can be allowed, for example, an adjustment of 5% can be made for two pixels inside the pattern, and an adjustment of 80% can be made for one pixel outside the pattern. Thus, it is possible to avoid making pixels whose final dose becomes too large. However, in embodiment 1, since defect correction is performed regardless of the drawing pattern, it is unclear whether the irradiation position of the distribution destination is inside or outside the pattern at the time of calculating the allocation rate for defect correction. Therefore, it is difficult to adjust the allocation rate based on the inside and outside of the pattern. Therefore, it is preferable to set an upper limit on the allocation rate. For example, it is preferable to set the upper limit to about 40%. In addition, it is preferable to set the maximum value of the dose modulation rate of the pixel of the position offset correction amount of each pixel and the total value of the dose modulation rate allocated from other pixels (total modulation rate) as the upper limit. This can avoid pixels with excessively high doses, and can suppress an increase in the maximum irradiation time, which results in a reduction in the drawing time.

[0095] Fig.13 FIG. 1 is a diagram for explaining another example of the method for performing defect correction using the peripheral pixels in Embodiment 1. When the allocation rate of the allocation destination exceeds the set upper limit, as Fig.13 As shown, just increase the number of allocation destinations. Fig.13 In the example of , the case where it is allocated to 11 pixels is shown.

[0096] Although this may result in poor accuracy, when the displacement of the center of gravity is not considered, the distribution rate δd may be determined simply by using the equation (2) obtained by dividing the 100% dose Δ by the number of distribution destinations N.

[0097] [Formula 2]

[0098] (2) δd = Δ / N

[0099] The defect correction data defines a dose modulation rate of 0% for the pixel responsible for the defect beam and a distribution rate (dose modulation rate) to at least one pixel as a distribution destination. For other pixels, a dose modulation rate of 100% is defined as solid data.

[0100] In addition, as described above, when creating the position shift correction data, the defect correction data creating unit 56 inputs the position shift correction data for correcting the individual position shift of each irradiation position of the multi-beam, and creates the defect correction data using the position shift correction data. Thus, for the pixel that the defective beam is responsible for, the dose modulation rate of 0% of itself and the dose modulation rate to at least one, for example, three or more pixels that are the distribution destinations are defined. Here, it is preferable to align the center of gravity position of the dose modulation rate of the distribution destination taking into account the position shift with the position of the pixel that the defective beam is responsible for. For the other pixels, the dose modulation rate of each dose modulation rate defined in the position shift correction data × 100% is defined.

[0101] The created defect correction data is stored in the storage device 144. The defect correction data may be created in consideration of the content of the positional shift correction data as described above, or may be stored in the storage device 144 as separate data.

[0102] As described above, as pre-processing before starting the drawing process, defect correction data (and positional deviation correction data) that do not depend on the drawing pattern are prepared in advance. Next, the drawing process is performed for each drawing pattern.

[0103] Here, the larger value (3) is obtained between the maximum value (1) of the dose modulation rate of the pixel for the position shift correction amount and the total value (total modulation rate) of the dose modulation rate allocated from other pixels, and the maximum value (2) of the dose modulation rate of the defect correction amount allocated to each pixel. If the reference value (4) of the individual dose corresponding to the drawing pattern is known, the dose actually irradiated to each pixel will not be greater than the value obtained by multiplying the two ((3)×(4)). Therefore, the value obtained by multiplying the two is taken as the maximum dose ((3)×(4)), and the maximum irradiation time obtained by dividing the maximum dose by the current density can be obtained in advance. Regarding the reference value (4) of the individual dose, if dose modulation such as proximity effect correction is not performed, the reference irradiation amount Dbase can be used. In the case of performing dose modulation such as proximity effect correction, as the reference value (4) of the individual dose, the value obtained by multiplying the maximum dose modulation rate such as proximity effect correction by the reference irradiation amount Dbase can be used.

[0104] As a dose calculation step (S120), the dose map preparation unit 62 (dose calculation unit) calculates the individual dose of each pixel 36 on the sample 101 corresponding to the drawing pattern for each drawing pattern. Specifically, the operation is performed as follows. First, the rasterization unit 60 reads the drawing data from the storage device 140, and calculates the pattern area density ρ' in the pixel 36 for each pixel 36. For example, this process is performed for each strip area 32.

[0105] Next, the dose map preparation unit 62 first divides the drawing area (here, for example, the strip area 32) into a plurality of adjacent grid areas (grid areas for calculation of proximity effect correction) in a grid shape with a predetermined size. The size of the adjacent grid area is preferably set to about 1 / 10 of the influence range of the proximity effect, for example, about 1 μm. The dose map preparation unit 62 reads the drawing data from the storage device 140, and for each adjacent grid area, calculates the pattern area density ρ of the pattern arranged in the adjacent grid area.

[0106] Next, the dose map preparation unit 62 calculates the proximity effect correction irradiation coefficient Dp(x) (corrected irradiation amount) for correcting the proximity effect for each neighboring grid area. The unknown proximity effect correction irradiation coefficient Dp(x) can be defined by a threshold model for proximity effect correction that uses the backscatter coefficient η, the irradiation amount threshold Dth of the threshold model, the pattern area density ρ, and the distribution function g(x), which is the same as the conventional method.

[0107] Next, the dose map preparation unit 62 calculates the incident irradiation amount D(x) (dose) for irradiating the pixel 36 for each pixel 36. The incident irradiation amount D(x) can be calculated as a value obtained by, for example, multiplying a preset reference irradiation amount Dbase by a proximity effect correction irradiation coefficient Dp and a pattern area density ρ'. The reference irradiation amount Dbase can be defined, for example, as Dth / (1 / 2+η). Based on the above, the originally desired incident irradiation amount D(x) corrected for the proximity effect based on the layout of the plurality of graphic patterns defined in the drawing data can be obtained.

[0108] Then, the dose map preparation unit 62 prepares a dose map that defines the incident irradiation amount D(x) of each pixel 36 in bar units. Such an incident irradiation amount D(x) of each pixel 36 is designed to be a predetermined incident irradiation amount D(x) irradiated to the control grid 27 of the pixel 36. In other words, the dose map preparation unit 52 prepares a dose map that defines the incident irradiation amount D(x) of each control grid 27 in bar units. The prepared dose map is stored in the storage device 144, for example.

[0109] As a dose correction process (S130), the dose correction unit 64 reads defect correction data from the storage device 144 for each drawing pattern, corrects the individual doses of each position on the sample corresponding to the drawing pattern through dose distribution, and obtains a corrected dose. The dose distribution uses a value obtained by multiplying the dose modulation rate defined in the read defect correction data by the individual dose of each position on the sample.

[0110] Specifically, the dose correction unit 64 first repeatedly allocates the rectangular unit regions 35 to the stripe region 32 according to the drawing order. This makes it possible to determine which beam is irradiated to each pixel 36 in the stripe region 32 .

[0111] The dose correction unit 64 calculates, for each pixel, a value obtained by multiplying a separate dose for each pixel corresponding to the depicted pattern by a dose modulation rate for the pixel defined in the defect correction data. In addition, the dose correction unit 64 calculates, for each pixel, a value obtained by multiplying a separate dose for each pixel corresponding to the depicted pattern by a dose modulation rate for the pixel to be the distribution destination defined in the defect correction data, and distributes it to the pixel to be the distribution destination. Next, the dose correction unit 64 adds the dose obtained by multiplying the dose variable rate of the pixel to the distributed dose for each pixel 36. In the pixel responsible for the defective beam, if there is a dose distributed from other pixels, the added dose is not zero. In this case, for the pixel responsible for the defective beam, a value obtained by multiplying the added dose by the dose modulation rate (0%) for the pixel defined in the defect correction data is calculated. In addition, it is preferable to remove the defective beam from the distribution destination of the dose in advance at the stage of making the defect correction data.

[0112] When the defect correction data and the positional shift correction data are stored separately in advance, first, a value obtained by multiplying the individual dose of each pixel corresponding to the drawing pattern by the dose variation rate of the pixel defined in the positional shift correction data is calculated. In addition, the dose correction unit 64 calculates a value obtained by multiplying the individual dose of the pixel by the dose modulation rate to the pixel to be allocated defined in the defect correction data for each pixel, and allocates it to the pixel to be allocated. Then, the dose correction unit 64 adds the dose obtained by multiplying the dose variation rate of the pixel to the allocated dose for each pixel 36. Next, a value obtained by multiplying the dose of each pixel added by the dose variation rate of the pixel defined in the defect correction data is calculated. In addition, the dose correction unit 64 calculates a value obtained by multiplying the individual dose of the pixel after addition by the dose modulation rate to the pixel to be allocated defined in the defect correction data for each pixel, and allocates it to the pixel to be allocated. Then, the dose correction unit 64 adds the dose obtained by multiplying the dose variation rate of the pixel to the allocated dose for each pixel 36. In addition, it is preferable to synthesize the defect correction data and the position shift correction data in advance and perform the defect correction and the position shift correction at the same time.

[0113] exist Figure 7In the flowchart shown, correction is not performed for defect beams other than the defect beam that is always turned off. However, this is not limited to this. It is also possible to further perform correction for excess dose irradiated by excess dose defect beams such as the defect beam that is always turned on. The correction method for excess dose can also be the same as the conventional method.

[0114] As an irradiation time calculation process (S140), the irradiation time calculation unit 72 calculates the irradiation time t corresponding to the dose of each pixel after correcting the position deviation of the beam and correcting the insufficient dose caused by the defective beam. The irradiation time t can be calculated by dividing the dose D by the current density J. The irradiation time t of each pixel 36 (control grid 27) is calculated as a value within the maximum irradiation time Ttr that can be irradiated by one emission of the multi-beam 20. The irradiation time t of each pixel 36 (control grid 27) is converted into grayscale value data of 0 to 1023 grayscales, in which the maximum irradiation time Ttr is set to 1023 grayscales (10 bits), for example. The grayscaled irradiation time data is stored in the storage device 142.

[0115] As a drawing process (S142), first, the drawing control unit 74 sorts the irradiation time data according to the drawing order and the emission order. Then, the irradiation time data is transmitted to the deflection control circuit 130 according to the emission order. The deflection control circuit 130 outputs a blanking control signal to the blanking aperture array mechanism 204 according to the emission order, and outputs a deflection control signal to the DAC amplifier units 132 and 134 according to the emission order. Then, the drawing mechanism 150 draws a drawing pattern on the sample 101 using the multi-beam 20 irradiated with the corrected dose.

[0116] As described above, in Embodiment 1, before starting the drawing process, defect correction data (and position shift correction data) that is not dependent on the drawing pattern is pre-made. Then, using the defect correction data (and position shift correction data), for each drawing pattern, the individual dose of each pixel corresponding to the drawing pattern is corrected. Even if the drawing pattern changes, the defect correction data (and position shift correction data) that has been made can be reused. Thus, there is no need to re-make the defect correction data (and position shift correction data) every time the drawing pattern changes. Therefore, the data processing time in the drawing process can be shortened.

[0117] Therefore, according to the first embodiment, in multi-beam drawing, it is possible to avoid a situation where the data processing for defect beam correction cannot keep up with the drawing processing speed.

[0118] The above embodiments are described with reference to specific examples. However, the present invention is not limited to these specific examples. In the above examples, the case where the irradiation time of each beam of the multi-beam 20 is controlled individually for each beam within the maximum irradiation time Ttr of one shot is described. However, it is not limited to this. For example, the maximum irradiation time Ttr of one shot is divided into a plurality of sub-shots with different irradiation times. And, for each beam, a combination of sub-shots is selected from the plurality of sub-shots in such a way that the irradiation time becomes one shot. And, it is preferred that the selected combination of sub-shots continuously irradiates the same pixel with the same beam, thereby controlling the irradiation time of one shot for each beam.

[0119] In addition, in the above example, a 10-bit control signal is input to control each control circuit 41, but the number of bits can be set appropriately. For example, a 2-bit or 3-bit to 9-bit control signal can also be used. In addition, a control signal of 11 bits or more can also be used.

[0120] In addition, descriptions of parts such as device configurations and control methods that are not directly necessary for the description of the present invention are omitted, but it is possible to select and use the necessary device configurations and control methods as appropriate. For example, descriptions of the control unit configuration for controlling the rendering device 100 are omitted, but it is possible to select and use the necessary control unit configuration as appropriate.

[0121] Furthermore, any multi-charged particle beam drawing apparatus and multi-charged particle beam drawing method that includes the elements of the present invention and can be appropriately designed and modified by a person skilled in the art are included in the scope of the present invention.

[0122] Industrial Applicability

[0123] One embodiment of the present invention relates to a multi-charged particle beam imaging device and a multi-charged particle beam imaging method, which are methods that can be used to reduce dimensional deviation of a pattern caused by multi-beam imaging, for example.

[0124] Description of Reference Numerals

[0125] 20 Multi-beam

[0126] 22 holes

[0127] 24 Control electrode

[0128] 25 through hole

[0129] 26 Counter electrode

[0130] 27 Control Grid

[0131] 28 pixels

[0132] 29 Secondary irradiation area

[0133] 30 Drawing area

[0134] 32 Stripe Area

[0135] 31 substrate

[0136] 33 Supporting platform

[0137] 34 Irradiation area

[0138] 35 Rectangular unit area

[0139] 36 pixels

[0140] 37, 39 Irradiation position

[0141] 41 Control circuit

[0142] 50Beam position offset map production department

[0143] 52 Position offset correction data production department

[0144] 54 Detection Department

[0145] 55 Determination

[0146] 56 Defect Correction Data Production Department

[0147] 60 Rasterization Unit

[0148] 62 Dose Mapping Production Department

[0149] 64 Dose Calibration Department

[0150] 72 Irradiation time calculation unit

[0151] 74 Drawing control unit

[0152] 100 Drawing Device

[0153] 101 Sample

[0154] 102 Electronic tube

[0155] 103 Drawing Room

[0156] 105 XY table

[0157] 110 Control Computer

[0158] 112 Memory

[0159] 130 Deflection control circuit

[0160] 132, 134DAC amplifier unit

[0161] 139 workbench position detector

[0162] 140, 142, 144 storage device

[0163] 150 Depicting Organization

[0164] 160 Control system circuit

[0165] 200 Electron Beam

[0166] 201 Electron Gun

[0167] 202 Lighting lens

[0168] 203 Forming aperture array substrate

[0169] 204 Blanking Aperture Array Mechanism

[0170] 205 Zooming Lens

[0171] 206 Restricted Aperture Substrate

[0172] 207 Objective

[0173] 208, 209 Deflector

[0174] 210 Reflector

[0175] 330 Diaphragm area

[0176] 332 Peripheral area

Claims

1. A multi-charged particle beam mapping device, characterized in that: have: A beam forming mechanism for forming a multi-charged particle beam; a defect correction data producing circuit which produces defect correction data using a dose distribution independently of a drawing pattern, the dose distribution defining each position of a unit area on a sample surface corresponding to an irradiation area of ​​the multi-charged particle beam as a whole with the same dose, the defect correction data defining a dose modulation rate for distributing the dose of a position responsible for a defective beam that is always beam cutoff in the multi-charged particle beam to one or more other pixels for correction; A storage device for storing the defect correction data; a dose calculation circuit that calculates, for each drawing pattern, a separate dose at each position on the sample corresponding to the drawing pattern; a dose correction circuit that reads the defect correction data from the storage device for each drawing pattern, corrects the individual doses at the positions on the sample corresponding to the drawing pattern by dose distribution, and obtains a corrected dose, wherein the dose distribution uses a value obtained by multiplying the dose modulation rate defined in the read defect correction data by the individual dose at the positions on the sample; as well as The drawing mechanism draws the drawing pattern on the sample using the multi-charged particle beam irradiated with the corrected dose.

2. The multi-charged particle beam drawing device according to claim 1, characterized in that: The defect correction data creation circuit inputs positional shift correction data for correcting individual positional shifts of respective irradiation positions of the multi-charged particle beams, and creates the defect correction data using the positional shift correction data.

3. The multi-charged particle beam drawing device according to claim 1, characterized in that: The drawing pattern is drawn on the sample by multiple drawing, The defect correction data generating circuit generates the defect correction data in such a way that the correction of the dose at the position responsible for the defect beam, which is performed in one of the plurality of passes of the multiple mapping, is performed by other passes.

4. The multi-charged particle beam drawing device according to claim 1, characterized in that: The defect correction data creation circuit creates the defect correction data by correcting the dose of the position where the defect beam is responsible using a peripheral beam that irradiates a position around the position where the defect beam is responsible.

5. The multi-charged particle beam drawing device according to claim 2, characterized in that: The device further includes a position shift correction data creation circuit that creates the position shift correction data for correcting individual position shifts of the irradiation positions of the multi-charged particle beams.

6. The multi-charged particle beam drawing device according to claim 5, characterized in that: The positional deviation correction data generating circuit calculates a modulation rate of the beam toward the target pixel and a modulation rate of the beam toward at least one pixel around the target pixel based on a ratio of an area shifted by the positional deviation of the beam toward the target pixel.

7. The multi-charged particle beam drawing device according to claim 4, characterized in that: The defect correction data production circuit, calculating a plurality of distribution rates for distributing the dose of the position responsible for the defect beam to a plurality of positions around the position responsible for the defect beam, The distribution ratio is determined so that the center of gravity position of the plurality of distribution ratios to be distributed becomes the position to which the defective beam is responsible.

8. A multi-charged particle beam characterization method, characterized in that: The steps include: Formation of multiple charged particle beams, Defect correction data is prepared using a dose distribution regardless of a drawing pattern used for drawing, the dose distribution defining each position of a unit area on a sample surface corresponding to an irradiation area of ​​the entire multi-charged particle beam with the same dose, the defect correction data defining a dose modulation rate for allocating the dose of a position responsible for a defective beam that is always beam cutoff in the multi-charged particle beam to one or more other pixels for correction, storing the defect correction data in a storage device, For each drawing pattern, a separate dose is calculated for each position on the sample corresponding to the drawing pattern. For each drawing pattern, the defect correction data is read from the storage device, and the individual doses at the positions on the sample corresponding to the drawing pattern are corrected by dose distribution, where the dose distribution uses a value obtained by multiplying the dose modulation rate defined in the read defect correction data by the individual doses at the positions on the sample to obtain a corrected dose. The drawing pattern is drawn on the sample using the multi-charged particle beam irradiated with the corrected dose.

9. The multi-charged particle beam drawing method according to claim 8, characterized in that: The defect correction data is also created using positional deviation correction data for correcting individual positional deviations of the irradiation positions of the multi-charged particle beams.

10. The multi-charged particle beam drawing method according to claim 8, characterized in that: The drawing pattern is drawn on the sample by multiple drawing. The defect correction data are generated in such a way that a correction of the dose at the location for which the defect beam is responsible, which is carried out in one of the plurality of passes of the multiple mapping, is carried out by means of other passes.

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