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

Abstract

To provide a device which can avoid unnecessary defect corrections when correcting excessive doses of defective beams across a drawing path of multiple drawing in multi-beam drawing.SOLUTION: The present invention includes: a dose determination unit for determining the position of a dose which is not zero in a proximity region including a defective position where a defective beam with an excessive dose of a multi-beam is to be applied for each processing region; a defective position dose data creation unit in which a dose for a defect is defined in the defective position when the dose which is not zero is defined; a pattern presence determination unit for determining the presence of a pattern by using dose data of each position for future irradiation for each unit region on a sample surface; and a drawing mechanism for skipping a unit region which has been determined to include no patterns by the pattern presence determination unit and moving to a unit region which has been determined to include a pattern on which drawing processing is to be performed, and performing correction to reduce an excessive dose caused by a defective dose in one of a plurality of drawing paths of multiple drawing in other drawing paths.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a multi-charged particle beam writing apparatus and a multi-charged particle beam writing method, and relates to, for example, a technique for reducing dimensional deviation of a pattern caused by multi-beam writing. [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 mask patterns are written onto mask blanks using an electron beam.

[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 each unblocked beam is reduced in size by an optical system to reduce the mask image, and the beams are deflected by a deflector to be irradiated onto the desired position on the sample.

[0004] In multi-beam writing, the dose irradiated from each beam is controlled by the irradiation time. However, if a failure in the blanking control mechanism or other factors makes it difficult to control the irradiation time, a defective beam may be generated, in which the beam is over-irradiated. If the required dose is not irradiated onto the sample, there is a problem that shape errors occur in the pattern formed on the sample. To address this problem, a technology has been proposed that corrects the excess dose by distributing it among multiple peripheral beams (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-021919 Summary of the Invention [Problem to be solved by the invention]

[0006] Although it is not yet publicly known, a technique is being considered for correcting excess dose caused by irradiation of defect beams across multiple writing passes in multi-beam writing. On the other hand, in multi-beam writing, for example, writing proceeds while shifting the rectangular area irradiated by the multi-beams on the writing area of ​​the sample. In this case, for rectangular areas where no pattern exists, it is desirable to skip the writing process of such rectangular areas in order to shorten the writing time.

[0007] However, when correcting excess dose due to a defect beam across multiple drawing passes in multiple drawing, a rectangular area including the position where the defect beam is irradiated in some drawing passes may not have a pattern. Dose data is generated independently between drawing passes. In this case, for example, data is generated in the first drawing pass assuming that defect correction will be performed on the position where the defect beam is irradiated in the second drawing pass. However, a rectangular area including the position where the defect beam is irradiated in the second drawing pass may not have a pattern. In this case, if the drawing process for the non-patterned area is skipped, the defect beam that was supposed to be irradiated in the second drawing pass will not be irradiated, and the assumption for correction in the first drawing pass will be invalid. As a result, unnecessary defect correction may be performed.

[0008] One aspect of the present invention provides an apparatus and method that can avoid unnecessary defect correction when correcting excess dose due to a defect beam across multiple writing passes in multi-beam writing. [Means for solving the problem]

[0009] A multi-charged particle beam writing apparatus according to one aspect of the present invention comprises: a beam forming mechanism for forming multiple charged particle beams; a dose data generating unit that generates dose data for each of a plurality of processing regions obtained by dividing the writing region on the sample surface, the dose data defining an individual dose amount at each position within the processing region; a dose determination unit for determining whether or not a position where a dose amount other than zero is defined exists in a region nearby the defect position to be irradiated with a defect beam of the multi-charged particle beam that will have an excessive dose amount for each processing region; a defect position dose data creating unit that creates defect dose data in which a defect dose is defined at a defect position when a dose amount with a non-zero value is defined in a nearby region; a pattern presence / absence determination unit that determines, for each unit area on the sample surface where an irradiation area of ​​the multi-charged particle beam is set, whether or not a pattern is present in the unit area using dose data of each position to be irradiated in the unit area; a writing mechanism that, when writing a pattern on a sample using a multi-charged particle beam, skips a unit area determined by a pattern presence / absence determination unit as having no pattern and moves the unit area to be written to a next unit area determined as having a pattern, thereby correcting an excess dose caused by a defective beam in any one of a plurality of writing passes of multiple writing so as to reduce it in another writing pass; Equipped with.

[0010] Also, a movable stage on which a sample is placed; a tracking deflector that performs tracking deflection of the multi-charged particle beam so that an irradiation area of ​​the multi-charged particle beam follows the movement of the stage; Furthermore, It is preferable that a unit area is set for each tracking control by tracking deflection.

[0011] Preferably, the pattern presence / absence determining unit determines that a pattern is present in each unit area.

[0012] Alternatively, the image processing device may further include a storage device for storing a result of determining whether or not a pattern exists for each unit area, In the second or subsequent drawing passes of the multiple drawing passes of multiple drawing, it is preferable to determine whether or not to correct the excess dose caused by the defective beam in that pass based on the result of determining whether or not a pattern exists for each unit area in the preceding pass.

[0013] Furthermore, it is preferable that the determination of the presence or absence of a pattern for each unit area is performed as a pre-processing before the start of the drawing process.

[0014] A multi-charged particle beam writing method according to one aspect of the present invention includes: forming a multi-charged particle beam; creating dose data for each of a plurality of processing regions into which the writing region on the sample surface is divided, the dose amount being defined for each position within the processing region; For each processing region, determining whether there is a position where a dose amount of a non-zero value is defined in a region nearby the defect position where the defect beam of the multi-charged particle beam is to be irradiated with an excessive dose amount; creating defect dose data in which a defect dose is defined at the defect position when a dose amount with a non-zero value is defined in the neighboring region; a step of determining, for each unit area on the sample surface where an irradiation area of ​​the multi-charged particle beam is set, whether or not a pattern exists in the unit area using dose data of each position to be irradiated in the unit area; a step of drawing a pattern on a sample using a multi-charged particle beam, skipping a unit area determined to have no pattern and moving the unit area to be subjected to drawing processing to a next unit area determined to have a pattern, and correcting an excess dose caused by a defective beam in any one of a plurality of drawing passes of multiple drawing so as to reduce it in another drawing pass; Equipped with.

[0015] The method further comprises a step of performing tracking deflection of the multi-charged particle beam so that the irradiation area of ​​the multi-charged particle beam follows the movement of a movable stage on which the sample is placed, It is preferable that a unit area is set for each tracking control by tracking deflection. [Effects of the Invention]

[0016] According to one aspect of the present invention, in multi-beam writing, when correction of excess dose due to a defect beam is performed across writing passes of multiple writing, unnecessary defect correction can be avoided. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a conceptual diagram showing a configuration of a drawing device according to a first embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing the configuration of a shaping aperture array substrate according to the first embodiment. [Figure 3] 2 is a cross-sectional view showing the configuration of a blanking aperture array mechanism in the first embodiment. FIG. [Figure 4] FIG. 2 is a conceptual diagram for explaining an example of a drawing operation in the first embodiment. [Figure 5] 3 is a diagram showing an example of a multi-beam irradiation area and a pixel to be written in the first embodiment. FIG. [Figure 6] FIG. 2 is a diagram for explaining an example of a multi-beam writing method according to the first embodiment. [Figure 7] FIG. 4 is a diagram showing an example of the presence or absence of a pattern in each drawing pass according to the first embodiment. [Figure 8] FIG. 2 is a flowchart showing the main steps of the writing method according to the first embodiment. [Figure 9] 5A and 5B are diagrams for explaining beam positional deviation and positional deviation periodicity in the first embodiment. [Figure 10] FIG. 2 is a diagram for explaining an example of a positional deviation correction method according to the first embodiment. [Figure 11]FIG. 4 is a diagram showing an example of defect beam correction in the first embodiment. [Figure 12] FIG. 10 is a diagram showing another example of defective beam correction in the first embodiment. [Figure 13] 10 is a diagram showing an example of the presence or absence of a pattern in a processing region and the presence or absence of a pattern for each main deflection region in a comparative example of the first embodiment. FIG. [Figure 14] 5 is a diagram showing an example of the presence or absence of a pattern in a processing region and the presence or absence of a pattern in each main deflection region in the first embodiment. FIG. [Figure 15] FIG. 11 is a flowchart showing the main steps of a writing method according to the third embodiment. [Figure 16] FIG. 11 is a flowchart showing the main steps of a writing method according to the fourth embodiment. [Figure 17] FIG. 13 is a conceptual diagram showing the configuration of a drawing device according to a fifth embodiment. [Figure 18] FIG. 13 is a flowchart showing the main steps of a writing method according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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.

[0019] 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. The lithography mechanism 150 includes an electron lens column 102 (multi-electron beam column) and a lithography chamber 103. The electron lens column 102 includes an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a collective blanking deflector 212, a limiting aperture substrate 206, an objective lens 207, a deflector 208, and a deflector 209. The lithography chamber 103 includes an XY stage 105. A sample 101, such as a resist-coated mask blank, which serves as a target substrate for lithography, is placed on the XY stage 105. The sample 101 includes an exposure mask used in manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured, etc. A mirror 210 for measuring the position of the XY stage 105 is also placed on the XY stage 105. A Faraday cup 106 is also placed on the XY stage 105.

[0020] The control system circuit 160 includes a control computer 110, a memory 112, a deflection control circuit 130, digital-to-analog conversion (DAC) amplifier units 132, 134, and 136, a stage position detector 139, and storage devices 140, 142, and 144 such as magnetic disk drives. The control computer 110, the memory 112, the deflection control circuit 130, the DAC amplifier units 132, 134, and 136, the stage position detector 139, and the storage devices 140, 142, and 144 are connected to one another via a bus (not shown). The deflection control circuit 130 is connected to the DAC amplifier units 132, 134, and 136 and a blanking aperture array mechanism 204. The output of the DAC amplifier unit 132 is connected to a deflector 209. The output of the DAC amplifier unit 134 is connected to a deflector 208. The output of the DAC amplifier unit 136 is connected to a collective blanking deflector 212. The deflector 208 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via a DAC amplifier 134. The deflector 209 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via a DAC amplifier 132. The collective blanking deflector 212 is composed of two or more electrodes, and each electrode is controlled by the deflection control circuit 130 via a DAC amplifier 136.

[0021] The stage position detector 139 irradiates a mirror 210 on the XY stage 105 with laser light and receives the light reflected from the mirror 210. Then, the position of the XY stage 105 is measured using the principle of laser interference based on the information on the reflected light.

[0022] The control computer 110 includes a rasterizer 50, a dose data generator 52, a beam position deviation map generator 54, a position deviation correction unit 56, a detector 57, an identification unit 58, a defect corrector 60, a finite dose determination unit 62, a defect dose data generator 64, an irradiation time calculator 66, a data processor 67, a NULL determination unit 68, and a writing controller 74. Each of the units, such as the rasterizer 50, the dose data generator 52, the beam position deviation map generator 54, a position deviation correction unit 56, a detector 57, an identification unit 58, a defect corrector 60, a finite dose determination unit 62, a defect dose data generator 64, an irradiation time calculator 66, a data processor 67, a NULL determination unit 68, and a writing controller 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 "unit" may use a common processing circuit (the same processing circuit) or may use a different processing circuit (separate processing circuit). Information input to and output from the rasterizing unit 50, dose data creating unit 52, beam position deviation map creating unit 54, position deviation correcting unit 56, detecting unit 57, identifying unit 58, defect correcting unit 60, finite dose determining unit 62, defect dose data creating unit 64, irradiation time calculating unit 66, data processing unit 67, NULL determining unit 68, and writing control unit 74, as well as information being calculated, are stored in memory 112 each time.

[0023] Furthermore, drawing data is input from outside the drawing device 100 and stored in the storage device 140. The drawing data usually defines information on a plurality of graphic patterns to be drawn. Specifically, a graphic code, coordinates, size, etc. are defined for each graphic pattern.

[0024] 1 shows the configuration necessary for explaining the first embodiment. The drawing device 100 may also include other configurations that are normally required.

[0025] FIG. 2 is a conceptual diagram showing the configuration of a shaping aperture array substrate in the first embodiment. In FIG. 2, holes (apertures) 22 are formed in a matrix of p columns (y direction) by q columns (x direction) (p, q≧2) at a predetermined arrangement pitch on the shaping aperture array substrate 203. In FIG. 2, for example, 512×512 columns of holes 22 are formed in the vertical and horizontal directions (x, y directions). Each hole 22 is formed as a rectangle of the same size and shape. Alternatively, they may be circles of the same diameter. The shaping aperture array substrate 203 (beam forming mechanism) forms multiple beams 20. Specifically, multiple beams 20 are formed by portions of electron beam 200 passing through these multiple holes 22. The arrangement of holes 22 is not limited to the grid-like arrangement shown in FIG. 2. For example, the holes in the kth column in the vertical direction (y direction) and the k+1th column in the horizontal direction (x direction) may be offset by a dimension a from each other. Similarly, the holes in the k+1th column and the k+2th column in the vertical direction (y direction) may be arranged with a shift of dimension b in the horizontal direction (x direction).

[0026] FIG. 3 is a cross-sectional view showing the configuration of the blanking aperture array mechanism according to the first embodiment. In the blanking aperture array mechanism 204, as shown in FIG. 3, a semiconductor substrate 31 made of silicon or the like is placed on a support base 33. The central portion of the substrate 31 is removed, for example, from the backside, to form a membrane region 330 (first region) with a thin film thickness h. The area surrounding the membrane region 330 is a peripheral region 332 (second region) with a thick film thickness H. The upper surfaces of the membrane region 330 and the peripheral region 332 are formed to be at the same height position or substantially at the same height position. The substrate 31 is held on the support base 33 at the backside of the peripheral region 332. The central portion of the support base 33 is open, and the membrane region 330 is located in the open region of the support base 33.

[0027] In the membrane region 330, passage holes 25 (openings) for passing through each beam of the multibeam 20 are opened at positions corresponding to the holes 22 of the shaping aperture array substrate 203 shown in FIG. 2. In other words, a plurality of passage holes 25 for passing through corresponding beams of the multibeam 20 using electron beams are formed in an array in the membrane region 330 of the substrate 31. A plurality of electrode pairs, each having two electrodes, are arranged on the membrane region 330 of the substrate 31 at positions facing each other across each passage hole 25. Specifically, on the membrane region 330, as shown in FIG. 3, pairs of a control electrode 24 for blanking deflection and a counter electrode 26 (blanker: blanking deflector: first deflector) are arranged on the membrane region 330, with the passage hole 25 sandwiched between them, in positions near each passage hole 25. Furthermore, a control circuit 41 (logic circuit) for applying a deflection voltage to the control electrode 24 for each passage hole 25 is arranged inside the substrate 31 and near each passage hole 25 on the membrane region 330. The counter electrode 26 for each beam is 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 is disposed. The CMOS inverter circuit is connected to a positive potential (Vdd: blanking potential: first potential) (e.g., 5 V) (first potential) and a ground potential (GND: second potential). An output line (OUT) of the CMOS inverter circuit is connected to a control electrode 24. On the other hand, a ground potential is applied to the counter electrode 26. A plurality of control electrodes 24, to which a blanking potential and a ground potential are switchably applied, are disposed on the substrate 31 at positions facing the corresponding counter electrodes 26 of the plurality of counter electrodes 26 across the corresponding passage holes 25 of the plurality of passage holes 25.

[0029] To the input (IN) of the CMOS inverter circuit, either an L (low) potential (e.g., ground potential) lower than the threshold voltage or an H (high) potential (e.g., 1.5 V) 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 becomes a positive potential (Vdd), and a corresponding one of the multi-beams 20 is deflected by an electric field due to a potential difference with the ground potential of the counter electrode 26, and is controlled so that the beam is turned OFF by being blocked 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 counter electrode 26, so that the corresponding one of the multi-beams 20 is not deflected, and the beam is controlled so that it passes through the limiting aperture substrate 206 and is turned ON.

[0030] Each electron beam in the multi-beams 20 passing through each passage hole is deflected by a voltage applied to two independent pairs of control electrodes 24 and counter electrodes 26. Blanking control is performed by this deflection. Specifically, the pairs of control electrodes 24 and counter electrodes 26 individually blank and deflect the corresponding beams in the multi-beams 20 by the potentials switched by the CMOS inverter circuits that serve as corresponding switching circuits. In this way, the multiple blankers perform blanking deflection of the corresponding beams in the multi-beams 20 that have passed through the multiple holes 22 (openings) in the shaping aperture array substrate 203.

[0031] 4 is a conceptual diagram for explaining an example of the writing operation in embodiment 1. As shown in Fig. 4, a writing region 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, for example.

[0032] In the example of FIG. 4, a first stripe layer is set, which is composed of multiple stripe regions 32 obtained by dividing the drawing area 30. A second stripe layer is set, which is composed of multiple stripe regions 32 that are shifted in the y direction by half the width of the stripe region 32 relative to the first stripe layer. Thus, in the example of FIG. 4, two stripe layers, the first stripe layer and the second stripe layer, are set. Therefore, by combining the first stripe layer and the second stripe layer, multiple stripe regions 32 are set that are aligned and partially overlap in the y direction. The example of FIG. 4 shows a case where adjacent stripe regions 32 in the y direction overlap each other by half their areas. It is also preferable to set one extra stripe region 32 in the second stripe layer from the end of the drawing area 30 in the -y direction. Next, an example of a drawing operation will be described.

[0033] First, the XY stage 105 is moved and adjusted so that the irradiation area 34 of the multibeam 20 is positioned at the left end of the first stripe region 32 of the second stripe layer, or further to the left. Then, the first stripe region 32 of the second stripe layer is written. When writing the first stripe region 32 of the second stripe layer, the XY stage 105 is moved, for example, in the −x direction, so that writing progresses relatively in the x direction. The XY stage 105 is moved continuously, for example, at a constant speed. After writing the first stripe region 32 of the second stripe layer is completed, the stage position is moved in the −y direction by an amount of displacement equal to half the width of the stripe region 32.

[0034] Next, the irradiation area 34 of the multibeam 20 is adjusted to be located at the right end of the first stripe region 32 of the first stripe layer, or at a position further to the right. Then, by moving the XY stage 105, for example, in the x direction, writing proceeds relatively in the -x direction. This results in writing of the first stripe region 32 of the first stripe layer. After writing of the first stripe region 32 of the first stripe layer is completed, writing of the second stripe region 32 of the second stripe layer is performed. By alternately writing the first stripe layer and the second stripe layer, multiple writing is performed at each position. Furthermore, in the above example, writing is performed while alternating directions, but this is not limiting, and writing may proceed in the same direction when writing each stripe region 32.

[0035] FIG. 5 is a diagram showing an example of a multi-beam irradiation region and a pixel to be written in the first embodiment. In FIG. 5, a plurality of control grids 27 (design grids) are set in the stripe region 32, for example, arranged in a grid pattern at a beam size pitch of the multi-beams 20 on the surface of the sample 101. The control grids 27 preferably have an arrangement pitch of, for example, about 10 nm. The plurality of control grids 27 are the designed irradiation positions of the multi-beams 20. The arrangement pitch of the control grids 27 is not limited to the beam size, and may be any size that can be controlled as the deflection position of the deflector 209, regardless of the beam size. A plurality of pixels 36 are set, virtually divided into a mesh shape with the same size as the arrangement pitch of the control grids 27, with each control grid 27 at its center. Each pixel 36 is an irradiation unit region for one beam of the multi-beams. The example of FIG. 5 shows a case where the writing area of ​​the sample 101 is divided, for example, in the y direction, into multiple stripe regions 32 each having a width substantially equal to the size of the irradiation area 34 (writing field) that can be irradiated with one shot of the multibeam 20 (beam array). The x-direction size of the irradiation area 34 can be defined as the value obtained by multiplying the inter-beam pitch of the multibeam 20 in the x direction by the number of beams in the x direction. The y-direction size of the irradiation area 34 can be defined as the value obtained by multiplying the inter-beam pitch of the multibeam 20 in the y direction by the number of beams in the y direction. Note that the width of the stripe regions 32 is not limited to this. Preferably, the size is n times the size of the irradiation area 34 (n is an integer greater than or equal to 1). In the example of FIG. 5, for example, a 512 × 512 array of multibeams is shown as an 8 × 8 array of multibeams. Furthermore, within the irradiation area 34, multiple pixels 28 (beam writing positions) that can be irradiated with one shot of the multibeam 20 are shown. In other words, the pitch between adjacent pixels 28 is the pitch between each beam of the designed multi-beam. In the example of Fig. 5, the area surrounded by the inter-beam pitch constitutes one sub-illumination area 29. In the example of Fig. 5, each sub-illumination area 29 is composed of 4 x 4 pixels.

[0036] FIG. 6 is a diagram illustrating an example of a multi-beam writing method according to the first embodiment. FIG. 6 illustrates a portion of the sub-irradiation area 29 written by each beam at coordinates (1,3), (2,3), (3,3), . . . , (512,3) in the k-th stage in the y-direction, among the multi-beams that write the stripe area 32 shown in FIG. 5 . The example in FIG. 6 illustrates, for example, a case in which four pixels are written (exposed) while the XY stage 105 moves a distance equivalent to eight beam pitches. While writing (exposing) these four pixels, the entire multi-beam 20 is deflected collectively by the deflector 208 so that the relative position of the irradiation area 34 with respect to the sample 101 does not shift due to the movement of the XY stage 105. This causes the irradiation area 34 to follow the movement of the XY stage 105. In other words, tracking control is performed. The deflector 208 serves as a tracking deflector and performs tracking deflection of the multi-beam 20 so that the irradiation area 34 of the multi-beam 20 follows the movement of the stage. The example of FIG. 6 shows a case where one tracking cycle is performed by drawing (exposing) four pixels while moving a distance of eight beam pitches.

[0037] Specifically, in each shot, a beam is irradiated for a writing time (irradiation time or exposure time) corresponding to each control grid 27 within the set maximum writing time. Specifically, each control grid 27 is irradiated with a corresponding ON beam among the multi-beams 20. Then, for each shot cycle time Ttr, which is the maximum writing time plus the settling time of the DAC amplifier, the irradiation position of each beam is moved to the next shot position by collective deflection by the deflector 209.

[0038] 6, when four shots have been taken, the DAC amplifier unit 134 resets the beam deflection for tracking control, thereby returning the tracking position to the tracking start position where tracking control was started.

[0039] Note that drawing of the first pixel row from the right in each sub-irradiation area 29 has been completed. Therefore, after tracking reset, in the next tracking cycle, the deflector 209 first deflects the beams so as to align (shift) the drawing positions of the corresponding beams with the control grid 27 of the pixel in the first row from the bottom and second from the right in each sub-irradiation area 29. By repeating this operation, drawing of all pixels is completed. If the sub-irradiation area 29 is made up of n x n pixels, n tracking operations are performed, each time with a different beam, to draw n pixels. In this way, all pixels in one n x n pixel area are drawn. Similar operations are performed at the same time for other n x n pixel areas within the multi-beam irradiation area, and drawing is performed in the same manner.

[0040] By this operation, as shown by irradiation areas 34a to 34o in FIG. 4, the drawing process proceeds while the irradiation area 34 is shifted on the stripe area 32 by, for example, 8 beam pitches, which is the stage movement amount in one tracking control.

[0041] Next, the operation of the drawing mechanism 150 in the drawing apparatus 100 will be described. An electron beam 200 emitted from an electron gun 201 (emission source) is illuminated by an illumination lens 202 onto the entire shaping aperture array substrate 203. A plurality of rectangular holes 22 (openings) are formed in the shaping aperture array substrate 203. The electron beam 200 then 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 in the shaping aperture array substrate 203, respectively. This results in the formation of a plurality of rectangular electron beams (multibeams 20). The multibeams 20 pass through corresponding blankers (first deflectors) in a blanking aperture array mechanism 204. Each blanker individually deflects the passing electron beam (performs blanking deflection).

[0042] The multi-beams 20 passing 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, electron beams deflected by the blankers of the blanking aperture array mechanism 204 are displaced from the central hole of the limiting aperture substrate 206 and are blocked by the limiting aperture substrate 206. On the other hand, electron beams 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 . Blanking control is performed by turning the blankers on and off, and the beams are controlled to be turned on and off. In this way, the limiting aperture substrate 206 blocks each beam deflected by the blankers to turn the beam off. Then, a single shot of beam is formed by the beams formed for each beam from when the beam is turned on until when the beam is turned off and passing through the limiting aperture substrate 206. 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 individual beams that have passed through the limiting aperture substrate 206 (the entire multibeams 20 that have passed through) are deflected collectively in the same direction by the deflectors 208 and 209, and each beam is irradiated onto its respective irradiation position on the sample 101. Ideally, the multibeams 20 that are irradiated at one time are aligned 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.

[0043] As described above, defective beams can occur in multi-beams. Defective beams include over-dose defective beams, which are beams that are irradiated with an excessive dose because the beam dose cannot be controlled, and under-dose defective beams, which are beams that are irradiated with an insufficient dose because the beam dose cannot be controlled. Over-dose defective beams include ON defect beams that are always ON and a portion of poorly controlled defect beams that are poorly controlled for irradiation time. Under-dose defective beams include OFF defect beams that are always OFF and the remainder of poorly controlled defect beams.

[0044] When a defect beam irradiates a sample with a dose exceeding the planned dose, a problem occurs in the shape of the pattern formed on the sample. To address this problem, defect correction is performed to offset the excess dose. In the first embodiment, multiple lithography is performed, in which lithography is performed using multiple lithography passes. Therefore, such defect correction is performed in a lithography pass different from the lithography pass irradiated with the defect beam. Meanwhile, in multi-beam lithography, for example, a rectangular area (an example of a unit area) irradiated by the multi-beam 20 on the lithography area of ​​the sample 101 is shifted as it progresses. Here, the rectangular area (beam array area) is the multi-beam irradiation area 34, which is a combination of sub-irradiation areas 29 (small areas) surrounded by each beam of the multi-beam 20 and adjacent beams. Note that the unit area is not limited to a rectangular shape. The shape of the unit area may be other shapes according to the arrangement shape of the multi-beam. In the example of FIG. 4 , the irradiation area 34 shifts, for example, by eight beam pitches per tracking cycle. Therefore, rectangular areas irradiated by the multi-beam 20 overlap on the stripe area 32, shifting by eight beam pitches. For example, in the rectangular area corresponding to irradiation area 34a, the first pixel row from the right in each sub-irradiation area 29 is the target of irradiation. For example, in the rectangular area corresponding to irradiation area 34b, the second pixel row from the right in each sub-irradiation area 29 is the target of irradiation. For example, in the rectangular area corresponding to irradiation area 34c, the third pixel row from the right in each sub-irradiation area 29 is the target of irradiation. For example, in the rectangular area corresponding to irradiation area 34d, the fourth pixel row from the right in each sub-irradiation area 29 is the target of irradiation. The irradiation target pixels are similarly shifted in the subsequent rectangular areas. In this case, for rectangular areas where no pattern exists in the irradiation target pixels, it is desirable to skip the drawing process for such rectangular areas in order to shorten the drawing time.

[0045] In addition, when the drawing process of the rectangular area is skipped, the entire multi-beam 20 including the defective beam 11 can be blocked by the limiting aperture substrate 206 by deflecting the entire multi-beam 20 at once using the collective blanking deflector 212 during the skip operation.

[0046] 7 is a diagram showing an example of the presence or absence of a pattern in each writing pass in embodiment 1. In FIG. 7, a pattern 12 is arranged in a rectangular area 13 where a certain tracking control is performed in the first writing pass (first pass). The rectangular area 13 includes a position where a defect beam 11 is irradiated in the second writing pass (second pass). The position where the defect beam 11 is irradiated in the first pass is not shown.

[0047] When creating dose data for irradiating the rectangular region 13 in the first pass, the data is generated on the assumption that defect correction will be performed in the second pass to correct the excess dose due to irradiation with the defect beam 11. Furthermore, the position irradiated with the defect beam 11 in the second pass is included in the rectangular region 13 where a certain tracking control is performed. Here, the rectangular region 13 including the position irradiated with the defect beam 11 in the second pass may become an area without a pattern, as shown in FIG. 7. Thus, when correction of excess dose due to the defect beam is performed across multiple drawing passes, the rectangular region 13 including the position irradiated with the defect beam in some drawing passes may become an area without a pattern. Dose data is generated independently between drawing passes. In this case, if the drawing process for the rectangular region 13 without a pattern is skipped in the second drawing pass, the defect beam 11 is not irradiated, and the assumption for correction in the first drawing pass is violated. As a result, unnecessary defect correction may be performed.

[0048] Conversely, there may be cases where the rectangular area 13 in the second pass includes a position irradiated with the defect beam in the first pass. When creating dose data for irradiating the rectangular area 13 in the second pass, the data is generated on the assumption that defect correction will be performed to correct the excess dose caused by irradiation with the defect beam in the first pass. However, there may be cases where the rectangular area including the position irradiated with the defect beam in the first pass becomes an area without a pattern. If the drawing process for the rectangular area without a pattern is skipped in the first drawing pass, the defect beam will not be irradiated, and the assumption for correction in the second drawing pass will be invalid. As a result, there is a problem in that unnecessary defect correction will be performed.

[0049] Therefore, in the first embodiment, when there is a pixel around the position where the defect beam is irradiated, for which a dose amount that is defined as a non-zero value (finite value) in design, the rectangular area 13 where tracking control is performed is controlled so as not to be skipped even if there is no pattern.

[0050] For example, if a defect beam is irradiated in the first-pass writing process, the rectangular area 13 targeted for irradiation at the position irradiated with the defect beam in the first pass may become an area without a pattern in the second pass. If there is no design pattern around the defect beam, no pattern shape error will occur due to the defect beam. Therefore, in such a case, the defect beam can be ignored, and the writing process may be skipped.

[0051] Fig. 8 is a flowchart showing the main steps of the writing method according to the embodiment 1. In Fig. 8, the writing method according to the embodiment 1 carries out a series of steps including a beam position deviation measuring step (S102), a defect beam detecting step (S104), a dose amount calculating step (S110), a position deviation correcting step for each pass (S112), a defect beam position specifying step for each pass (S120), a defect beam correcting step (S122), a defect vicinity finite dose determining step (S130), a defect dose data creating step (S132), an irradiation time calculating step (S142), a data processing step (S144), a main deflector data NULL determining step (S146), and a writing step (S150).

[0052] Each of the defect beam correction process (S122), defect vicinity finite dose determination process (S130), defect dose data creation process (S132), irradiation time calculation process (S142), data processing process (S144), main deflection data NULL determination process (S146), and drawing process (S150) is performed for each drawing pass.

[0053] In the beam position deviation amount measuring step (S102), the drawing apparatus 100 measures the amount of deviation of the irradiation position of each beam of the multibeam 20 on the surface of the sample 101 from the corresponding control grid 27.

[0054] FIG. 9 is a diagram illustrating beam positional deviation and positional deviation periodicity in the first embodiment. In the multi-beam 20, as shown in FIG. 9( a), distortion occurs in the exposure field due to the characteristics of the optical system. This distortion causes the actual irradiation positions 39 of each beam to deviate from the irradiation positions 37 when the beam is irradiated onto an ideal grid. Therefore, in the first embodiment, the amount of positional deviation of the actual irradiation positions 39 of each beam is measured. Specifically, the multi-beam 20 is irradiated onto a resist-coated evaluation substrate, and the position of the resist pattern generated by developing the evaluation substrate is measured using a position measuring device. This allows the amount of positional deviation for each beam to be measured. If it is difficult to measure the size of the resist pattern at the irradiation position of each beam using a position measuring device for the shot size of each beam, a figure pattern (e.g., a rectangular pattern) of a size measurable by the position measuring device is written using each beam. Then, the edge positions on both sides of the figure pattern (resist pattern) are measured, and the amount of positional deviation of the target beam can be measured from the difference between the midpoint between the two edges and the midpoint of the designed figure pattern. The obtained misalignment data of the irradiation position of each beam is input to the writing device 100 and stored in the storage device 144. Furthermore, in multi-beam writing, writing progresses while shifting the irradiation region 34 within the stripe region 32. For example, in the writing sequence described with reference to FIG. 6, the positions of the irradiation regions 34 move sequentially from 34a to 34o during writing of the stripe region 32, as shown in the lower part of FIG. 4. Periodicity occurs in the misalignment of each beam with each movement of the irradiation region 34. Alternatively, in the case of a writing sequence in which each beam irradiates all pixels 36 within the corresponding sub-irradiation region 29, periodicity occurs in the misalignment of each beam for each unit region 35 (35a, 35b, ...) that is at least the same size as the irradiation region 34, as shown in FIG. 9(b). Therefore, if the misalignment amount of each beam for the irradiation region 34 of the beam array is measured, the measurement result can be reused. In other words, it is sufficient to measure the misalignment amount of each beam at each pixel 36 within the corresponding sub-irradiation region 29.

[0055] The beam position deviation map creation unit 54 then first creates a beam position deviation map (1) that defines the amount of deviation of each beam for each pixel 36 in a single rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, i.e., for each beam array. Specifically, the beam position deviation map creation unit 54 reads deviation data for the irradiation position of each beam from the storage device 144 and creates the beam position deviation map (1) using the data as map values. Which beam irradiates the control grid 27 of each pixel 36 in a single rectangular unit area 35 on the sample surface corresponding to the irradiation area 34 of the entire multibeam 20 is determined by the writing sequence, as described with reference to FIG. 6 , for example. Therefore, the beam position deviation map creation unit 54 identifies the beam responsible for irradiating each control grid 27 of each pixel 36 in a single unit area 35 according to the writing sequence, and calculates the amount of deviation of the beam. The created beam position deviation map (1) is stored in the storage device 144.

[0056] In the defect beam detection step (S104), the detection unit 57 detects defect beams from the multi-beams 20. An ON defect beam that is always ON always irradiates the beam for the maximum irradiation time per shot, regardless of the controlled dose. Alternatively, irradiation continues even when moving between pixels. An OFF defect beam that is always OFF always remains OFF, regardless of the controlled dose. Specifically, under the control of the writing control unit 74, the writing mechanism 150 controls each of the multi-beams 20 to be turned ON by the blanking aperture array mechanism 204, and controls all the remaining beams to be turned OFF. In this state, a beam for which no current is detected by the Faraday cup 106 is detected as an OFF defect beam. Conversely, from this state, the control is switched to turn the detection target beam OFF. At this time, a beam for which a current is always detected by the Faraday cup 106 despite switching from beam ON to beam OFF is detected as an ON defect beam. After switching from beam ON to beam OFF, a beam in which current is detected by the Faraday cup 106 for a predetermined period of time is detected as a poorly controlled defective beam. By checking all beams in the multi-beam 20 in order using the same method, it is possible to detect the presence or absence of a defective beam, its type, and the position of the defective beam. Here, the case where defective beams other than ON defective beams are also detected is described, but it is also possible to only detect ON defective beams that are always ON. Information on the detected defective beams is stored in the memory device 144.

[0057] In the dose calculation step (S110), the dose data creation unit 52 (dose calculation unit) creates dose data for each of the processing regions into which the writing region on the surface of the sample 101 is divided, in which the individual dose amount at each position within the processing region is defined. Specifically, the operation is as follows. First, the rasterization unit 50 reads the writing data from the storage device 140 and calculates, for each pixel 36, the pattern area density ρ' within the pixel 36. This process is performed, for example, for each stripe region 32.

[0058] Next, the dose data creation unit 52 first virtually divides the writing region (here, for example, the stripe region 32) into a plurality of proximity mesh regions (mesh regions for calculating proximity effect correction) in a mesh shape with a predetermined size. The size of the proximity mesh region is preferably set to about 1 / 10 of the range of influence of the proximity effect, for example, about 1 μm. Dose Data Creation Department 52 reads out the drawing data from the storage device 140, and calculates, for each proximity mesh region, the pattern area density ρ of the pattern to be placed in that proximity mesh region.

[0059] Next, the dose data generation unit 52 calculates a proximity effect correction irradiation coefficient Dp(x) (corrected dose) for correcting the proximity effect for each proximity mesh region. The unknown proximity effect correction irradiation coefficient Dp(x) can be defined by a threshold model for proximity effect correction similar to the conventional method, using the backscattering coefficient η, the dose threshold Dth of the threshold model, the pattern area density ρ, and the distribution function g(x).

[0060] Next, the dose data generation unit 52 calculates, for each pixel 36, an incident irradiation dose D(x) (dose) for irradiating the pixel 36. The incident irradiation dose D(x) may be calculated, for example, as a value obtained by multiplying a preset reference irradiation dose Dbase by a proximity effect correction irradiation coefficient Dp and a pattern area density ρ'. The reference irradiation dose Dbase can be defined, for example, as Dth / (1 / 2 + η). As a result, the original desired incident irradiation dose D(x) with the proximity effect corrected can be obtained based on the layout of the multiple graphic patterns defined in the drawing data.

[0061] The dose data creation unit 52 performs the above-described processing for each processing region obtained by dividing the stripe region 32. For example, a rectangular unit region 35 having the same size as the irradiation region 34 is used as the processing region. The dose data creation unit 52 then creates a dose map that defines the incident irradiation dose D(x) for each pixel 36 in processing region units. The incident irradiation dose D(x) for each pixel 36 is the incident irradiation dose D(x) that is intended to be applied to the control grid 27 of the pixel 36 in terms of design. The created dose map is stored, for example, in the storage device 144.

[0062] In the positional deviation correction step for each pass (S112), the positional deviation correction unit 56 creates a dose map in which the individual positional deviations of the irradiation positions of the multi-beams 20 are corrected for each writing pass.

[0063] First, the dose amount for each pixel for each drawing pass is defined. Specifically, the operation is as follows. The misalignment correction unit 56, for example, reads out a dose map from the storage device 144, and calculates the dose amount for each drawing pass by dividing the dose amount defined for each pixel by the number of drawing passes. Next, for each drawing pass, it corrects the misalignment of the beam that irradiates each pixel. Which beam irradiates which pixel for each pass is determined by the drawing sequence.

[0064] FIG. 10 is a diagram illustrating an example of a positional deviation correction method according to the first embodiment. The example in FIG. 10(a) illustrates a case in which a beam a' irradiated onto a pixel at coordinates (x, y) is misaligned toward the -x, -y side. To correct the misalignment of a pattern formed by the misaligned beam a' to a position that matches the pixel at coordinates (x, y) as shown in FIG. 10(b), the misalignment can be corrected by distributing the dose of irradiation corresponding to the misalignment to pixels on the opposite side of the direction of the surrounding pixels. In the example in FIG. 10(a), the dose of irradiation corresponding to the misalignment of the pixel at coordinates (x, y-1) may be distributed to the pixel at coordinates (x, y+1). The dose of irradiation corresponding to the misalignment of the pixel at coordinates (x-1, y) may be distributed to the pixel at coordinates (x+1, y). The dose of irradiation corresponding to the misalignment of the pixel at coordinates (x-1, y-1) may be distributed to the pixel at coordinates (x+1, y+1).

[0065] In the first embodiment, a misalignment correction distribution amount is calculated that distributes the irradiation amount to the beam for at least one surrounding pixel in proportion to the amount of beam misalignment. The misalignment correction data creation unit 52 calculates the modulation rate of the beam for the pixel and the modulation rate of the beam for at least one pixel surrounding the pixel in accordance with the ratio of the area shifted due to the beam misalignment for the pixel. Specifically, for each surrounding pixel where the beam is shifted from the pixel of interest and part of the beam overlaps, the ratio of the shifted area (area of ​​the overlapping beam part) divided by the beam area is calculated as the distribution amount (beam modulation rate) for the pixel located on the opposite side of the pixel of interest from the overlapping pixel.

[0066] 10(a), the area ratio shifted to the pixel at coordinate (x, y-1) can be calculated by (x-direction beam size - (-x) direction shift amount) x y-direction shift amount / (x-direction beam size x y-direction beam size). Therefore, the distribution amount (beam modulation rate) V to be distributed to the pixel at coordinate (x, y+1) for correction can be calculated by (x-direction beam size - (-x) direction shift amount) x y-direction shift amount / (x-direction beam size x y-direction beam size).

[0067] 10(a), the area ratio shifted to the pixel at coordinates (x-1, y-1) can be calculated by the formula: -x direction shift amount × -y direction shift amount / (x direction beam size × y direction beam size). Therefore, the distribution amount (beam modulation rate) W to be distributed to the pixel at coordinates (x+1, y+1) for correction can be calculated by the formula: -x direction shift amount × -y direction shift amount / (x direction beam size × y direction beam size).

[0068] In the example of Figure 10(a), the area ratio shifted to the pixel at coordinate (x-1, y) can be calculated by the -x direction shift amount × (y direction beam size - (-y) direction shift amount) / (x direction beam size × y direction beam size). Therefore, the distribution amount (beam modulation rate) Z to be distributed to the pixel at coordinate (x+1, y) for correction can be calculated by the -x direction shift amount × (y direction beam size - (-y) direction shift amount) / (x direction beam size × y direction beam size).

[0069] As a result, the remaining portion that has not been distributed, that is, the modulation factor U of the beam of the pixel at coordinates (x, y), can be calculated by 1-VWZ.

[0070] In this way, for each pixel 36 in a beam array unit, in other words, in one rectangular unit area 35 on the sample surface corresponding to the irradiation area 34, the modulation rate of the beam to that pixel and the modulation rate of the beam to at least one surrounding pixel to which the beam is distributed are calculated.

[0071] Then, for each pixel 36, the misalignment correction unit 56 calculates, for each drawing pass, a value obtained by multiplying the dose defined for that pixel by the modulation rate of the beam to that pixel. The misalignment correction unit 56 also calculates, for each pixel 36, a value obtained by multiplying the dose defined for that pixel by the modulation rate of the beam to at least one surrounding pixel to which the dose is to be distributed. The calculated value is then distributed to the destination pixel. For each drawing pass, the misalignment correction unit 56 calculates, for each pixel 36, a dose amount obtained by multiplying the dose defined for that pixel by the modulation rate of the beam to that pixel and adding up the value distributed from other pixels. This allows a dose map for each drawing pass in which the misalignment has been corrected (a dose map after misalignment correction for each pass) to be created. The created dose map after misalignment correction for each pass is stored in the storage device 144.

[0072] As a step of identifying the defective beam position for each pass (S120), 58 specifies the pixel to be irradiated by the overdose defect beam including the always-on defect beam for each beam array unit for each writing pass, in other words, for each pixel 36 in one rectangular unit area 35 on the sample surface corresponding to the irradiation area 34. As described above, which beam irradiates the control grid 27 of each pixel 36 in the rectangular unit area 35 is determined by the writing sequence.

[0073] In the defect beam correction step (S122), the defect corrector 60 corrects, for each drawing pass, the excess dose that has become excessive due to irradiation of the defect beam in another drawing pass so as to reduce it.

[0074] FIG. 11 illustrates an example of defect beam correction in the first embodiment. FIG. 11(a) illustrates a case where, for example, four-pass multiplex writing (multiplicity=4) is performed. In this case, for pixels not irradiated with the defect beam, the dose in each writing pass is defined as T(x) / pass, which is the dose T(x) irradiated to each pixel divided by the number of writing passes (here, 4). However, for pixels irradiated with the defect beam, this results in an overdose if left as is. Therefore, since the dose in the writing pass irradiated with the defect beam cannot be controlled, the dose is corrected to a dose obtained by subtracting the excess dose Δ in the other writing passes. In the example of FIG. 11(b), the defect beam is irradiated in one of the four writing passes. In this case, first, the excess amount Δ relative to T(x) / pass is calculated. Then, for the remaining three writing passes irradiated with the normal beam, the dose is corrected to a dose obtained by subtracting Δ / 3 from each dose T(x) / pass.

[0075] FIG. 12 illustrates another example of defect beam correction in the first embodiment. The designed dose at the position where the defect beam is irradiated may be smaller than the overdose Δ. In such cases, it is difficult to correct the overdose Δ using only the pixel. In such cases, the overdose Δ or the excess dose that cannot be fully corrected at the pixel irradiated with the defect beam is distributed to the surrounding beams. Therefore, the defect correction unit 60 corrects the excess dose that is excessive due to the defect beam irradiation in other irradiated passes by distributing it to the surrounding beams for each lithography pass. As shown in FIG. 12, the excess dose that cannot be fully corrected is distributed to, for example, three irradiation positions 39a, 39c, and 39g located around the irradiation position of the defect beam 11. Each distribution amount is calculated so that the center of gravity of each distribution amount is the irradiation position of the defect beam 11. The defect beam can be corrected by subtracting the calculated distributed dose from the beam dose at the target irradiation position.

[0076] 13A and 13B are diagrams showing an example of the presence or absence of a pattern in a processing region and the presence or absence of a pattern for each main deflection region in a comparative example of the first embodiment. FIG. 13A shows the presence or absence of a pattern in a processing region in one of multiple writing passes of multiple writing. Here, a case is shown in which a rectangular unit region 35 is used as the processing region. In the example of FIG. 13A, a design pattern 12 is placed in the rectangular unit region 35. In addition, in this writing pass, a defect beam 11 is irradiated near the pattern 12. When writing such a rectangular unit region 35, as described above, a rectangular region 13 that becomes a main deflection region is set for each tracking control. 13(b), for example, a rectangular area 13a is shown as the main deflection area for the first tracking control. In the rectangular area 13a, for example, the first pixel row from the right in each sub-irradiation area 29 is the target pixel. In the example of FIG. 13(b), the defect beam 11 is shown as the target pixel. 13(c) shows, for example, a rectangular area 13b that serves as the main deflection area for the second tracking control. In the rectangular area 13b, for example, the second pixel row from the right in each sub-irradiation area 29 is the drawing target. The example of FIG. 13(c) shows a case where the target pixel is a partial pattern 9a that is part of the pattern 12. Fig. 13(d) shows, for example, rectangular area 13c that serves as the main deflection area for the third tracking control. In rectangular area 13c, for example, the third pixel row from the right in each sub-irradiation area 29 is the drawing target. In the example of Fig. 13(d), a partial pattern 9b, which is another part of pattern 12, is shown as the target pixel. Of these main deflection regions, no pattern is placed in rectangular region 13a. Therefore, the drawing process for rectangular region 13a is skipped. In this case, since defect beam 11 is not irradiated, if defect correction is performed in another drawing pass, the correction will be unnecessary. Therefore, in the first embodiment, under certain conditions, control is performed so that the drawing process for rectangular region 13a is not skipped.

[0077] As the defect vicinity finite dose determination process (S130), the finite dose determination unit 62 (dose determination unit) determines, for each drawing pass and for each processing area, whether there is a position in the vicinity of the defect position where a defect beam in the multi-beam 20 that will have an excessive dose is to be irradiated, where a dose amount that is not zero (finite value) is defined.

[0078] FIG. 14 shows an example of the presence or absence of a pattern in a processing region and the presence or absence of a pattern for each main deflection region in the first embodiment. FIG. 14(a) shows the presence or absence of a pattern in a processing region A in one of multiple writing passes of multiple writing. Here, a rectangular unit region 35 is used as the processing region A. In the example of FIG. 14(a), a design pattern 12 is arranged within the rectangular unit region 35, as in FIG. 13(a). In addition, in this writing pass, a defect beam 11 is irradiated near the pattern 12. Here, the finite dose determination unit 62 determines whether a position (pixel) where a dose amount of a non-zero value (finite value) is defined exists in a nearby region C including a defect position (defective pixel) to be irradiated with the defect beam 11. It is preferable to assume that the nearby region C is a correction region for correcting the positional deviation of the pixel to be irradiated with the defect beam. For example, it is preferable to assume a pixel region within a radius of several pixels centered on the pixel to be irradiated with the defect beam. Alternatively, it is preferable to assume a pixel region within a radius of 1 to 2 beam size pitches centered on the pixel to be irradiated with the defect beam. Here, a rectangular region is shown as the neighboring region C, but this is not limiting. For example, a circular region is also preferable. In addition, a margin region B is set around the processing region A to take into account the defect beam in the processing region adjacent thereto. The margin width is preferably set to, for example, a few pixels to 1 to 2 beam pitches.

[0079] The finite dose determination unit 62 determines whether the defect beam 11 is within the processing region A and whether there is a pixel in the neighboring region C for which a dose amount of a non-zero value (finite value) is defined in design. In this case, it is assumed that the pixel in the neighboring region C for which a dose amount of a non-zero value (finite value) is defined does not exceed the margin region B. 14(a), the defect beam 11 is located within the processing area A, and part of the pattern 12 is located within the nearby area C, so it is determined that there is a pixel within the nearby area C for which a dose amount of a non-zero value (finite value) is defined in design. Since the pixel within the nearby area C for which a dose amount of a non-zero value (finite value) is defined does not exceed the margin area B, there is no problem with the premise. Therefore, the finite dose determination unit 62 determines that there is a pixel for which a dose amount is defined as a non-zero value (finite value). The dose amount of each pixel uses a value defined in a dose map stored in the storage device 144. Here, it is preferable to use a dose map after positional deviation correction for each pass as the dose map.

[0080] In the defect dose data creation step (S132), the defect dose data creation unit 64 (defect position dose data creation unit) creates defect dose data in which the defect dose is defined at the defect position when a non-zero (finite) dose is defined in the nearby region C. In the example of FIG. 14(a), defect dose data is created at the position irradiated with the defect beam 11. As the defect dose, for example, the maximum dose for each drawing pass is set. The maximum dose for each drawing pass can be the maximum dose of the dose for each pixel defined in the dose map (the dose map after positional deviation correction for each pass).

[0081] In the irradiation time calculation step (S142), the irradiation time calculation unit 66 calculates the irradiation time t corresponding to the dose of each pixel. 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 with one shot of the multi-beam 20. The irradiation time t of each pixel 36 (control grid 27) is converted into gradation value data of 0 to 1023 gradations, for example, with the maximum irradiation time Ttr being 1023 gradations (10 bits). The gradated irradiation time data is stored in the storage device 142.

[0082] In the data processing step (S144), the data processing unit 67 rearranges the irradiation time data for each pixel in the order of the main deflection region and the shot for each writing pass. The rectangular region 13 serving as the main deflection region is set for each tracking control using tracking deflection. A portion of the example shown in FIG. 14(a) when rearranging the data in the order of the main deflection region will be described. FIG. 14(b) shows, for example, a rectangular region 13a serving as the main deflection region for the first tracking control. In the rectangular region 13a, for example, the first pixel row from the right in each sub-irradiation region 29 is the writing target. The example shown in FIG. 14(b) shows a case where the target pixel is the defect beam 11. If defect dose data is defined at the position of the defect beam 11, the result will be the same as the state in which the defect pattern 17 is defined as shown in FIG. 14(b). Similarly to FIG. 13(c), FIG. 14(c) shows, for example, a rectangular region 13b serving as the main deflection region for the second tracking control. In rectangular region 13b, for example, the second pixel column from the right in each sub-irradiation region 29 is the drawing target. Similar to FIG. 13(c), the example of FIG. 14(c) illustrates a case where partial pattern 9a, which is part of pattern 12, is the target pixel. Similar to FIG. 13(d), FIG. 14(d) illustrates rectangular region 13c, which is the main deflection region for the third tracking control, for example. Similar to FIG. 13(d), the example of FIG. 14(d) illustrates a case where partial pattern 9b, which is another part of pattern 12, is the target pixel. Of these main deflection regions, the rectangular region 13a has been changed from a state in which no pattern was arranged as shown in FIG. 13(b) to a state in which a defect pattern 17 is arranged as shown in FIG. 14(b).

[0083] As described above, the shot data is divided for each main deflection region.

[0084] In the main deflector data NULL determination step (S146), the NULL determination unit 68 (pattern presence / absence determination unit) determines the presence or absence of a pattern in each rectangular region 13 on the surface of the sample 101 where the irradiation region 34 of the multi-beam 20 is set, using dose data for each position to be irradiated in the rectangular region 13. The irradiation time data of the rectangular region 13 that becomes the main deflector region becomes the main deflector data. When there is no main deflector data, i.e., when there is no pattern, it is determined as NULL (no pattern). In all of Figures 14(b) to 14(d), it is determined as non-NULL (pattern present). In particular, in the rectangular region 13a irradiated by the defect beam 11, even if there is no pattern in the design, defect dose data is defined, so the writing process is not skipped.

[0085] In the writing step (S150), the writing mechanism 150 skips writing processing of the rectangular region 13 determined to have no pattern and moves the rectangular region 13 to be written processing to the next rectangular region 13 having a pattern, and writes a pattern on the sample 101 using the multi-beam 20 while correcting an excess dose caused by the defect beam 11 in any of the writing passes of the multiple writing passes in the multiple writing, in the other writing passes. In the example of FIG. 14 , for example, even if defect correction is performed in the first writing pass on the assumption that the defect beam 11 will be irradiated in the second writing pass, the defect beam 11 is irradiated without being skipped in the second writing pass. Therefore, the defect correction in the first writing pass can be effectively performed. Similarly, for example, even if defect correction is performed in the second writing pass on the assumption that the defect beam 11 will be irradiated in the first writing pass, the defect beam 11 is irradiated without being skipped in the first writing pass. Therefore, the defect correction in the second writing pass can be effectively performed.

[0086] As described above, according to the first embodiment, in multi-beam writing, when the correction of the excess dose by the defect beam 11 is performed across writing passes of multiple writing, unnecessary defect correction can be avoided.

[0087] Embodiment 2 In the first embodiment, a case has been described in which defect dose data is created at the irradiation position of the defect beam, so that rectangular area 13 without a pattern is determined to have a pattern in the main deflector data NULL determination step (S146). In the second embodiment, other configurations will be described. The configuration of the writing apparatus in the second embodiment is the same as that in FIG. 1. The flowchart showing the main steps of the writing method in the second embodiment is the same as that in FIG. 8. Points not specifically explained below are the same as those in the first embodiment.

[0088] In the main deflector data NULL determination step (S146) in the second embodiment, the NULL determination unit 68 (pattern presence / absence determination unit) determines each rectangular region 13 as non-NULL (pattern present) regardless of the presence or absence of a pattern. Other points are the same as those in the first embodiment.

[0089] In the second embodiment, the defect vicinity finite dose determination step (S130) and the defect dose data creation step (S132) may be omitted. In such a case, the finite dose determination unit 62 and the defect dose data creation unit 64 may be omitted.

[0090] This eliminates the need to skip any rectangular area 13, but also avoids a situation where the defect beam 11 is not irradiated. This allows all defect corrections to function effectively.

[0091] Embodiment 3 Fig. 15 is a flowchart showing the main steps of the writing method according to the embodiment 3. Fig. 15 is the same as Fig. 8 except that the determination result in the main deflector data NULL determination step (S146) is stored in a storage device and the determination result in the main deflector data NULL determination step (S146) is fed back.

[0092] The configuration of the writing apparatus in the third embodiment is the same as that in Fig. 1. However, in the third embodiment, the finite dose determination unit 62 and the defect dose data creation unit 64 may be omitted. Below, the points not particularly explained are the same as those in the first embodiment.

[0093] In the third embodiment, the determination result in the main deflector data NULL determination step (S146) is stored in the storage device 144.

[0094] Therefore, in the defect beam correction step (S122), the defect correction unit 60 determines whether to correct the excess dose caused by the defect beam 11 in the second or subsequent drawing pass of the multiple drawing passes of multiple drawing, based on the determination result of the presence or absence of a pattern in the main deflector data NULL determination step (S146) for each rectangular area in the preceding pass. For example, whether a defect beam was irradiated in the first drawing pass can be determined from the determination result of the presence or absence of a pattern in the main deflector data NULL determination step (S146). Therefore, for example, in the second drawing pass, based on such determination result, defect correction is performed if a defect beam was irradiated in the first drawing pass, and defect correction is not performed if a defect beam was not irradiated. This makes it possible to avoid unnecessary defect correction.

[0095] Embodiment 4 Fig. 16 is a flowchart showing the main steps of the writing method according to the fourth embodiment. Fig. 16 is the same as Fig. 15 except that the steps in all writing passes from the beam position deviation amount measuring step (S102) to the main deflector data NULL determining step (S146) are performed as pre-processing before starting the writing process of the first writing pass. Therefore, like the third embodiment, the determination result in the main deflector data NULL determining step (S146) is stored in the storage device 144 and is fed back.

[0096] The configuration of the writing apparatus in the fourth embodiment is the same as that in Fig. 1. However, in the fourth embodiment, the finite dose determination unit 62 and the defect dose data creation unit 64 may be omitted. Below, the points not particularly explained are the same as those in the first embodiment.

[0097] In the fourth embodiment, as pre-processing before starting the writing process of the first writing pass, each step in all writing passes from the beam position deviation amount measuring step (S102) to the main deflector data NULL determining step (S146) is performed. Therefore, the determination of the presence or absence of a pattern for each rectangular region 13 is performed as pre-processing before starting the writing process.

[0098] As a result, in the defect beam correction step (S122), the defect correction unit 60 can determine, for each writing pass, whether a defect beam has been irradiated in another writing pass from the determination result of the presence or absence of a pattern in the main deflector data NULL determination step (S146). Therefore, the defect correction unit 60 determines whether to correct the excess dose caused by the defect beam 11 in that writing pass, using the determination result of the presence or absence of a pattern in the main deflector data NULL determination step (S146). In the fourth embodiment, the determination results of the presence or absence of patterns in the main deflector data NULL determination step (S146) for all writing passes are completed before starting the writing process of the first writing pass. Therefore, in the fourth embodiment, it is also possible to determine whether a defect beam will be irradiated in a subsequent writing pass. Therefore, for example, in the first writing pass, it is possible to determine whether to correct the defect beam scheduled to be irradiated in the second writing pass.

[0099] Embodiment 5. FIG. 17 is a conceptual diagram showing the configuration of a lithography device according to the fifth embodiment. FIG. 17 is the same as FIG. 1 except that a determination unit 61 is further added to the control computer 110. Each of the "units" such as the rasterization unit 50, dose data creation unit 52, beam position deviation map creation unit 54, position deviation correction unit 56, detection unit 57, identification unit 58, defect correction unit 60, determination unit 61, finite dose determination unit 62, defect dose data creation unit 64, irradiation time calculation unit 66, data processing unit 67, NULL determination unit 68, and lithography control 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 the rasterization unit 50, dose data creation unit 52, beam position deviation map creation unit 54, position deviation correction unit 56, detection unit 57, identification unit 58, defect correction unit 60, judgment unit 61, finite dose judgment unit 62, defect dose data creation unit 64, irradiation time calculation unit 66, data processing unit 67, NULL judgment unit 68, and drawing control unit 74, as well as information being calculated, are stored in memory 112 each time.

[0100] Fig. 18 is a flowchart showing the main steps of the writing method in the embodiment 5. Fig. 17 is the same as Fig. 8 except that a determination step (S128) is added before the defect vicinity finite dose determination step (S130).

[0101] In addition, the contents other than those specifically explained below are the same as those in the first embodiment.

[0102] The contents of each of the beam position deviation measurement process (S102), defect beam detection process (S104), dose calculation process (S110), position deviation correction process for each pass (S112), defect beam position identification process for each pass (S120), and defect beam correction process (S122) are the same as those in embodiment 1.

[0103] In the determination step (S128), the determination unit 61 determines whether the size of the region where only a zero dose is defined is equal to or smaller than a threshold value. Specifically, the determination unit 61 references the dose data after positional deviation correction for each pass and determines whether the size of the region where only a zero dose is defined is equal to or smaller than 1 / n or n times the size of the rectangular region, where n is a natural number. If the size of the region where only a zero dose is defined is not equal to or smaller than the threshold value, the process proceeds to the defect vicinity finite dose determination step (S130). If the size of the region where only a zero dose is defined is equal to or smaller than the threshold value, the defect vicinity finite dose determination step (S130) and the defect dose data creation step (S132) are skipped, and the process proceeds to the irradiation time calculation step (S142). In other words, the defect vicinity finite dose determination step (S130) and the defect dose data creation step (S132) are performed only for regions where there is no pattern of a certain size.

[0104] The contents of each step after the defect vicinity finite dose determination step (S130) are the same as those in embodiment 1. When the defect vicinity finite dose determination step (S130) and the defect dose data creation step (S132) are skipped, it is preferable to configure the main deflector data NULL determination step (S146) to always determine non-NULL (pattern present).

[0105] As described above, by skipping small areas among areas without a pattern, it is possible to reduce the drawing processing time.

[0106] The above describes an embodiment with reference to specific examples. However, the present invention is not limited to these specific examples. In the above example, a case has been described in which the irradiation time of each beam of the multi-beam 20 is individually controlled for each beam within the maximum irradiation time Ttr for one shot. However, the present invention is not limited to this. For example, the maximum irradiation time Ttr for one shot is divided into multiple sub-shots with different irradiation times. Then, for each beam, a combination of sub-shots is selected from the multiple sub-shots so that the irradiation time for one shot is achieved. Then, it is also preferable to control the irradiation time for one shot for each beam by continuously irradiating the same pixel with the same beam using the selected combination of sub-shots.

[0107] In the above example, a 10-bit control signal is input to control each control circuit 41, but the number of bits may be set as appropriate. For example, a 2-bit, or 3-9-bit control signal may be used. Note that a control signal of 11 or more bits may also be used.

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

[0109] In addition, all other multi-charged particle beam writing apparatuses and multi-charged particle beam writing methods 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]

[0110] 9 Partial Pattern 11 Defective beam 12 patterns 13 Rectangular area 20 Multibeam 22 holes 24 control electrode 25 Passing hole 26 Counter electrode 27 Control Grid 28 pixels 29 Sub-irradiation area 30 drawing area 32 stripe area 31 PCB 33 Support stand 34 Irradiation area 35 Rectangular unit area 36 pixels 39 Irradiation position 41 Control circuit 50 Rasterization section 52 Dose Data Creation Department 54 Beam position deviation map creation unit 56 Position deviation correction unit 57 Detector 58 Specific part 60 Defect correction unit 61 Judgment section 62 Finite dose determination unit 64 Defect Dose Data Creation Department 66 Irradiation time calculation section 67 Data Processing Department 68 NULL judgment section 74 Drawing control unit 100 drawing device 101 Sample 102 Electron Telescope 103 Drawing room 105 XY stage 106 Faraday Cup 110 Control computer 112 memory 130 Deflection control circuit 132, 134, 136 DAC amplifier unit 139 Stage Position Detector 140,142,144 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 208,209 Deflector 210 Mirror 212 collective blanking deflector 330 Membrane Region 332 Outer area

Claims

1. a beam forming mechanism for forming multiple charged particle beams; a dose data generating unit that generates dose data for each of a plurality of processing regions obtained by dividing the writing region on the sample surface, the dose data defining an individual dose amount at each position within the processing region; a dose determination unit that determines whether or not a position where a dose amount of a non-zero value is defined exists in a region nearby the defect position where the defect beam of the multi-charged particle beam is to be irradiated with an excessive dose amount for each of the processing regions; a defect position dose data creating unit that creates defect dose data in which a defect dose is defined at the defect position when a dose amount with a value other than zero is defined in the neighboring region; a pattern presence / absence determination unit that determines, for each unit area on the sample surface where an irradiation area of ​​the multi-charged particle beam is set, the presence or absence of a pattern in the unit area using dose data of each position to be irradiated in the unit area; a drawing mechanism that, when drawing a pattern on the sample using the multi-charged particle beam, skips a unit area determined by the pattern presence / absence determining unit as having no pattern and moves the unit area to be subjected to drawing processing to a next unit area determined as having a pattern, thereby correcting an excess dose caused by the defective beam in any one of a plurality of drawing passes of multiple drawing so as to reduce it in another drawing pass; A multi-charged particle beam lithography system equipped with the above.

2. a movable stage on which the sample is placed; a tracking deflector that performs tracking deflection of the multi-charged particle beam so that an irradiation area of ​​the multi-charged particle beam follows the movement of the stage; Furthermore, 2. The multi-charged particle beam drawing apparatus according to claim 1, wherein the unit area is set for each tracking control by the tracking deflection.

3. 3. The multi-charged particle beam drawing apparatus according to claim 1, wherein the pattern presence / absence determining unit determines whether a pattern exists in each unit area.

4. a storage device for storing a result of determining whether or not a pattern exists for each unit area; 3. The multi-charged particle beam drawing apparatus according to claim 1, wherein in a second or subsequent drawing pass of the multiple drawing passes of the multiple drawing, it is determined whether or not correction of an excess dose caused by the defect beam is required in that pass based on a result of determining whether or not a pattern exists for each unit area in a preceding pass.

5. 5. The multi-charged particle beam drawing apparatus according to claim 1, wherein the determination of the presence or absence of a pattern for each unit area is performed as a pre-processing before starting a drawing process.

6. forming a multi-charged particle beam; creating dose data for each of a plurality of processing regions into which the writing region on the sample surface is divided, the dose amount being defined for each position within the processing region; determining whether or not there is a position where a dose amount other than zero is defined in a nearby area including a defect position to be irradiated with a defect beam of the multi-charged particle beam that has an excessive dose amount for each of the processing areas; creating defect dose data in which a defect dose is defined at the defect position when a dose amount with a non-zero value is defined in the neighboring region; a step of determining, for each unit area on the sample surface where an irradiation area of ​​the multi-charged particle beam is set, whether or not a pattern exists in the unit area using dose data of each position to be irradiated in the unit area; a step of drawing a pattern on the sample using the multi-charged particle beam, skipping a unit area determined to have no pattern and moving the unit area to be subjected to drawing processing to a next unit area determined to have a pattern when performing the drawing, and correcting an excess dose caused by the defective beam in any one of a plurality of drawing passes of multiple drawing so as to reduce it in another drawing pass; A multi-charged particle beam writing method comprising:

7. performing tracking deflection of the multi-charged particle beam so that an irradiation area of ​​the multi-charged particle beam follows movement of a movable stage on which the sample is placed; 7. The multi-charged particle beam writing method according to claim 6, wherein the unit area is set for each tracking control by the tracking deflection.

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