JP6627632B2 - Multi charged particle beam writing apparatus and multi charged particle beam writing method - Google Patents

Description

  The present invention relates to a multi-charged particle beam writing apparatus and a multi-charged particle beam writing method.

  With the increase in integration of LSIs, circuit line widths of semiconductor devices have been further miniaturized. As a method for forming an exposure mask (a reticle is used for a stepper or a scanner) for forming a circuit pattern on these semiconductor devices, an electron beam drawing technique having excellent resolution has been used. I have.

  A writing apparatus using a multi-beam can irradiate a large number of beams at one time (one shot) as compared with the case of writing with one electron beam, so that the throughput can be greatly improved. In a multi-beam writing apparatus, for example, an electron beam emitted downward from an electron gun passes through an aperture member having a plurality of holes to form a multi-beam.

  In such a multi-beam writing apparatus, the shot size may change for each writing adjustment / for each apparatus due to an error in the mounting position of the aperture member, an error in the size of the hole formed in the aperture member, and the like. If the drawing is performed without considering the change in the shot size, there is a problem that the whole layout is enlarged or reduced, or the pattern connection accuracy is deteriorated, so that the drawing accuracy is deteriorated.

JP 2006-251207 A JP, 2012-527765, A Patent No. 5270891 JP 2015-162504 A JP 2009-88848 A

  The present invention has been made in view of the above-described conventional situation, and provides a multi-charged particle beam writing apparatus and a multi-charged particle beam writing method capable of preventing deterioration of writing accuracy even when a shot size of a multi-beam changes. That is the task.

A multi-charged particle beam drawing apparatus according to one embodiment of the present invention includes a boundary of pixels obtained by dividing a drawing area of a substrate into a mesh, an irradiation area of the multi-charged particle beam, and the drawing area with a predetermined width in a predetermined direction. A data region determination unit that determines a data region based on the boundary of the stripe region, and a deflection coordinate adjustment that adjusts a deflection coordinate of the multi-charged particle beam so as to associate the pixel boundary with the irradiation region boundary. Unit, based on the positional relationship between each beam of the multi-charged particle beam and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data by 1 A correction unit that divides the beam into the above-described beams, and calculates a corrected dose by adding the distributed dose in each of the beams; and a correction unit that calculates the corrected dose based on the adjusted deflection coordinates. Deflecting the multi charged particle beam Te, wherein a drawing unit for drawing a pattern by irradiating the corrected dose of the beam, comprises a, for each pixel of the data area, surrounding the dose of the beam corresponding to the pixel The correction dose is calculated using a correction map that defines a ratio of distribution to the beams .

  In the multi-charged particle beam drawing apparatus according to one aspect of the present invention, the correction unit calculates, for each pixel, the corrected irradiation amount from the barycentric position of the pixel and the irradiation amount and the barycenter position of the beam corresponding to the pixel. It is characterized in that it is calculated.

  In the multi-charged particle beam drawing apparatus according to one aspect of the present invention, when the data area determination unit determines that the data area is larger than an irradiation area of the multi-charged particle beam, the irradiation area is included in the data area. It is characterized in that shot data corresponding to a portion located on the outer side is complemented.

  A multi-charged particle beam drawing apparatus according to one embodiment of the present invention includes a stage on which the substrate is placed and moved, and a plurality of openings formed therein, and the multi-charged particle beam passes through the plurality of openings. Aperture member forming a particle beam, of the multi-charged particle beam, a blanking plate in which a plurality of blankers for switching on / off of the corresponding beam are arranged, and the beams turned on by the plurality of blankers are collectively collected. A deflector that deflects to follow the movement of the stage, deflects the beam to a first drawing position, and performs tracking control to follow a movement of the stage during beam drawing for a predetermined time; After a lapse of a predetermined time, the beam deflection is reset to return the beam to the direction opposite to the stage moving direction. A deflection control unit for controlling the deflector, wherein the deflection control unit performs writing and tracking control by deflecting the beam to a second writing position after writing at the first writing position, After drawing at the second drawing position, the beam is deflected to the third drawing position to perform drawing and tracking control.

  The multi-charged particle beam drawing apparatus according to one aspect of the present invention adds a shot for irradiating the pixel when a positional shift between the pixel and a beam corresponding to the pixel is equal to or more than a predetermined amount.

A multi-charged particle beam drawing apparatus according to one embodiment of the present invention includes a boundary of pixels obtained by dividing a drawing area of a substrate into a mesh, an irradiation area of the multi-charged particle beam, and the drawing area with a predetermined width in a predetermined direction. A data region determination unit that determines a data region based on the boundary of the stripe region, and a deflection coordinate adjustment that adjusts a deflection coordinate of the multi-charged particle beam so as to associate the pixel boundary with the irradiation region boundary. Unit, based on the positional relationship between each beam of the multi-charged particle beam and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data by 1 A correction unit that divides the beam into the above-described beams, and calculates a corrected dose by adding the distributed dose in each of the beams; and a correction unit that calculates the corrected dose based on the adjusted deflection coordinates. A drawing unit that deflects the multi-charged particle beam and irradiates the beam of the corrected irradiation amount to draw a pattern, and when a positional shift between the pixel and the beam corresponding to the pixel is equal to or more than a predetermined amount, A shot for irradiating the pixel is added, and a shot is added when a center of the pixel is not included in a beam corresponding to the pixel.

In the multi-charged particle beam drawing method according to one embodiment of the present invention, the drawing area of the substrate is divided into meshes, the boundaries of the pixels, the irradiation area of the multi-charged particle beam, and the drawing area are divided by a predetermined width in a predetermined direction. Determining a data area based on the boundary of the striped area, adjusting a deflection coordinate of the multi-charged particle beam so as to associate the boundary of the pixel with the boundary of the irradiation area, and Based on the positional relationship between each beam of the particle beam and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data is distributed to one or more beams. Calculating a corrected dose by adding the distributed doses in each of the beams; and a multi-charged particle beam based on the adjusted deflection coordinates. Deflect, and a step of drawing a pattern by irradiating a beam of the corrected dose for each pixel of the data area, the ratio of distributing the dose of the beam corresponding to the pixel to the periphery of the beam The correction dose is calculated using the defined correction map .

  In the multi-charged particle beam drawing method according to one aspect of the present invention, the irradiation position of the multi-charged particle beam is subjected to tracking control for following the movement of a stage on which the substrate is mounted, and after a predetermined time has elapsed, the beam deflection is reset. And returning the beam to a direction opposite to the stage movement direction, deflecting the beam to a first drawing position, performing drawing and tracking control, and after drawing at the first drawing position, changing the beam to a first drawing position. After drawing at the second drawing position, the beam is deflected to the third drawing position to perform drawing and tracking control.

  In the multi-charged particle beam drawing method according to one aspect of the present invention, a shot for irradiating the pixel is added when a positional shift between the pixel and a beam corresponding to the pixel is equal to or more than a predetermined amount.

  According to the present invention, it is possible to prevent the writing accuracy from deteriorating even when the shot size of the multi-beam changes.

1 is a schematic configuration diagram of a drawing apparatus according to an embodiment of the present invention. (A), (b) is a figure which shows the example of a structure of an aperture member. FIG. 4 is a diagram illustrating an example of a drawing operation. FIG. 4 is a diagram illustrating an example of a multi-beam irradiation area and a drawing target pixel. 5 is a flowchart illustrating a drawing method according to the embodiment of the present invention. FIG. 4 is a diagram showing an irradiation area of a multi-beam in which a beam size has changed. It is a figure which shows the example of correction of an irradiation amount. (A)-(d) is a figure which shows the shot by a comparative example. (A)-(d) is a figure which shows the example of the shot by embodiment. FIG. 7 is a diagram illustrating an example of determining a data area. It is a figure showing an example of adjustment of deflection coordinates. It is a figure which shows the example of correction of an irradiation amount. It is a figure which shows the example of correction of an irradiation amount. (A)-(c) is a figure explaining the process at the time of making a data area large. It is a figure showing an example of a tracking operation. (A), (b) is a figure which shows the example of the positional relationship of a pixel mesh and a beam mesh.

  Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, but may be a beam using charged particles such as an ion beam.

  FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to an embodiment. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The writing apparatus 100 is an example of a multi-charged particle beam writing apparatus.

  The drawing unit 150 includes the electronic lens barrel 102 and the drawing chamber 103. In the electron beam column 102, an electron gun 201, an illumination lens 202, an aperture member 203, a blanking plate 204, a reduction lens 205, a limiting aperture member 206, an objective lens 207, and a deflector 208 are arranged.

  In the drawing room 103, an XY stage 105 that can be continuously moved is arranged. On the XY stage 105, a mask substrate 101 to be drawn at the time of writing is arranged. The mask substrate 101 includes an exposure mask for manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured, and the like. In addition, the mask substrate 101 includes a mask blank on which a resist is applied and on which nothing is drawn yet. On the XY stage 105, a mirror 210 for measuring the position of the XY stage 105 is further arranged.

  The control unit 160 includes a control computer 110, a memory 112, a deflection control circuit 130, a stage position detector 139, and storage devices 140, 142, 144, and 146 such as magnetic disk devices. These are connected to each other via a bus. In the storage device 140, the drawing data is externally input and stored.

  The control computer 110 includes a data area determination unit 50, a deflection coordinate adjustment unit 52, a correction map creation unit 54, a shot data creation unit 56, a correction unit 58, and a drawing control unit 60. These functions may be configured by hardware such as an electric circuit, or may be configured by software. When configured with software, a program that implements at least a part of the functions may be stored in a recording medium and read and executed by a computer having a CPU. The recording medium is not limited to a removable medium such as a magnetic disk or an optical disk, but may be a fixed recording medium such as a hard disk device or a memory. Information such as a calculation result in the control computer 110 is stored in the memory 112 each time.

  FIGS. 2A and 2B are conceptual diagrams illustrating a configuration example of the aperture member 203. FIG. In FIG. 2A, the aperture member 203 has holes (openings) 22 of m rows (in the y direction) × n rows (in the x direction) (n, m ≧ 2) arranged in a matrix at a predetermined arrangement pitch. Is formed. For example, 512 × 512 rows of holes 22 are formed vertically and horizontally (x, y directions). Each hole 22 is formed by a rectangle having the same size. Hole 22 may be circular.

  When a part of the electron beam 200 passes through each of the plurality of holes 22, the multi-beams 20a to 20e are formed. Here, an example in which the holes 22 are arranged in two or more rows in both the vertical and horizontal directions (x, y directions) is shown, but the present invention is not limited to this. For example, one of the vertical and horizontal (x, y directions) may be a plurality of rows and the other may be only one row.

  The way of arranging the holes 22 is not limited to the case where the vertical and horizontal directions are arranged in a lattice as shown in FIG. For example, as shown in FIG. 2B, holes in the k-th row in the vertical direction (y direction) and the holes in the k + 1-th row are displaced by the dimension a in the horizontal direction (x direction). Is also good. Similarly, the holes of the (k + 1) th row in the vertical direction (y direction) and the holes of the (k + 2) th row may be displaced from each other by the dimension b in the horizontal direction (x direction).

  The blanking plate 204 has a passage hole (opening) for passing each of the multi-beams at a position corresponding to each hole 22 of the aperture member 203 shown in FIGS. 2A and 2B. Then, a set of blanking deflection electrodes (blankers: blanking deflectors) is arranged with each passing hole interposed therebetween. One of the two electrodes is applied with a deflection voltage based on a control signal from the deflection control circuit 130, and the other is grounded.

  The electron beams 20a to 20e passing through the passage holes are deflected independently by blankers, and blanking control is performed. In this manner, the plurality of blankers perform blanking deflection of the corresponding beams among the multi-beams that have passed through the plurality of holes 22 (openings) of the aperture member 203.

  FIG. 3 is a conceptual diagram illustrating an example of a drawing operation. As shown in FIG. 3, the drawing area 30 of the mask substrate 101 is virtually divided into a plurality of strip-shaped stripe areas 32 having a predetermined width in the y direction, for example.

  First, the XY stage 105 is moved so that the irradiation area 34 that can be irradiated by one irradiation of the multi-beam 20 is positioned at the left end of the first stripe area 32 or at a position further to the left, and the drawing is performed. Is started. When drawing the first stripe region 32, the XY stage 105 is moved in the -x direction, for example, so that the drawing is relatively advanced in the x direction. The XY stage 105 is, for example, continuously moved at a predetermined speed.

  After the drawing of the first stripe region 32 is completed, the stage position is moved in the −y direction, and the irradiation region 34 is relatively positioned in the y direction at the right end of the second stripe region 32 or further to the right. Then, by moving the XY stage 105 in, for example, the x direction, drawing is similarly performed in the −x direction.

  In the third stripe region 32, writing is performed in alternate directions, such as writing in the x direction, and in the fourth stripe region 32, writing is performed in the −x direction. Can be shortened. However, the present invention is not limited to the case where the drawing is performed while changing the direction alternately, and the drawing may be performed in the same direction when the respective stripe regions 32 are drawn. In one shot, a maximum of the same number of shot patterns as each hole 22 are formed at a time by the multi-beam formed by passing through each hole 22 of the aperture member 203.

  FIG. 4 is a diagram illustrating an example of a multi-beam irradiation area and a drawing target pixel. In FIG. 4, the stripe region 32 is divided into a plurality of mesh regions 40 in a mesh shape, for example, with a beam size of a multi-beam. Each mesh area 40 is a drawing target pixel (drawing position). The size of the drawing target pixel is not limited to the beam size. For example, the size may be 1 / n (n is an integer of 1 or more) of the beam size. In the example of FIG. 4, the drawing area of the mask substrate 101 has a plurality of stripes each having a width smaller than the size (shot size) of the irradiation area 34 that can be irradiated by one irradiation of the multiple beams 20a to 20e in the y direction, for example. The case where the image is divided into regions 32 is shown. The width of the stripe region 32 is not limited to this, and may be, for example, n times (n is an integer of 1 or more) the irradiation region 34.

  In the irradiation area 34, a plurality of pixels 24 (beam drawing positions) that can be irradiated by one irradiation of the multi-beams 20a to 20e are shown. In other words, the pitch between the adjacent pixels 24 is the pitch between the beams of the multi-beam. In the example of FIG. 4, one sub-pitch region 26 is surrounded by four adjacent pixels 24 and is a square region including one pixel 24 of the four pixels 24. FIG. 4 shows a case where each sub-pitch region 26 is composed of 4 × 4 pixels.

  Next, the operation of the drawing unit 150 will be described. The electron beam 200 emitted from the electron gun 201 (emission unit) illuminates the entire aperture member 203 almost vertically by the illumination lens 202. When the electron beam 200 passes through the plurality of holes 22 of the aperture member 203, for example, a plurality of rectangular electron beams (multi-beams) 20a to 20e are formed. The multiple beams 20a to 20e pass through respective blankers of the blanking plate 204. The blanker individually deflects the passing electron beam 20 so that the beam is turned ON only during the calculated writing time (irradiation time) and the beam is turned OFF otherwise (performs blanking deflection).

  The multi-beams 20 a to 20 e that have passed through the blanking plate 204 are reduced by the reduction lens 205 and proceed toward a central hole formed in the limiting aperture member 206. The electron beam deflected by the blanker of the blanking plate 204 to be turned off by the beam is displaced from the center hole of the limiting aperture member 206 (blanking aperture member) and is blocked by the limiting aperture member 206. On the other hand, the electron beam that has not been deflected by the blanker of the blanking plate 204 (deflected to be the beam ON) passes through the center hole of the limiting aperture member 206.

  A beam of one shot is formed by a beam formed after the beam is turned on and before the beam is turned off and passed through the restriction aperture member 206. The multi-beam that has passed through the limiting aperture member 206 is focused by the objective lens 207 to form a pattern image with a desired reduction ratio, and each beam (the entire multi-beam 20) is collectively deflected in the same direction by the deflector 208, and Each drawing position (irradiation position) on the substrate 101 is irradiated.

  When the XY stage 105 is continuously moving, tracking control is performed by the deflector 208 so that the beam writing position (irradiation position) follows the movement of the XY stage 105. Laser is irradiated from the stage position detector 139 toward the mirror 210 on the XY stage 105, and the position of the XY stage 105 is measured using the reflected light. The multiple beams irradiated at one time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes of the aperture member 203 by the above-described desired reduction ratio.

  The writing apparatus 100 sequentially irradiates a multi-beam, which is a shot beam, while sequentially shifting a plurality of pixels (pixels 24 in FIG. 4) while shifting the writing position while following the movement of the XY stage 105 during each tracking operation. The drawing operation is performed by a raster scan method.

  FIG. 5 is a flowchart illustrating a drawing method according to the embodiment. This drawing method includes a data area determination step S102, a deflection coordinate adjustment step S104, a correction map creation step S106, a drawing data acquisition step S202, a shot data creation step S204, a correction step S206, and a drawing step S208. Prepare.

  In the drawing data acquisition step S202, the shot data creation unit 56 reads out and acquires the drawing data (graphic data) from the storage device 140. The shot data creation unit 56 reads the corresponding drawing data from the storage device 140 for each stripe area, for example.

  In the shot data creation step S204, the shot data creation unit 56 calculates, for each pixel (or for each of a plurality of pixel groups), the area density of the pattern arranged therein, using the drawing data. For example, the shot data creation unit 56 assigns a plurality of graphic patterns defined in the drawing data to corresponding pixels. Then, the shot data creation unit 56 calculates the area density of the figure pattern to be arranged for each pixel.

  Further, the shot data creation unit 56 calculates, for each pixel, a beam irradiation amount to the pixel. Here, the irradiation amount of the electron beam per shot (or irradiation time T: also called shot time or exposure time) is calculated for each pixel. It is preferable that the reference irradiation amount (or irradiation time T) is obtained in proportion to the calculated pattern area density. It is preferable that the irradiation amount finally calculated is a corrected irradiation amount obtained by correcting the dimensional change for a phenomenon that causes dimensional fluctuations such as a proximity effect, a fogging effect, and a loading effect (not shown) by the irradiation amount. The irradiation time can be defined by a value obtained by dividing the irradiation amount D by the current density J.

  The shot data creation unit 56 calculates the irradiation amount for each pixel assuming that the beam is reduced at a predetermined reduction ratio (for example, 200%). However, due to an error in the mounting position of the aperture member 203, an error in the size of the hole 22 formed in the aperture member 203, and the like, the reduction ratio of the beam changes, and the shot size (beam size) changes.

  FIG. 6 shows an example of the relationship between the pixel 40 for which the shot data creation unit 56 calculates the irradiation amount and the irradiation region 34 of the multi-beam whose beam size has changed. Pixel 40 is indicated by a dashed line. FIG. 6 shows an example in which a multi-beam is composed of four beams. As shown in FIG. 6, when the size of each beam of the multi-beam changes, one beam is positioned over a plurality of pixels 40, and the boundary between the irradiation area 34 and the pixel 40 does not match. Therefore, it is necessary to correct the irradiation amount of each pixel 40 in consideration of the change in the beam size.

  For example, as shown in FIG. 7, a beam B corresponding to a pixel at a coordinate (x, y) has, in addition to a pixel at a coordinate (x, y), adjacent coordinates (x, y + 1), (x + 1, y), It is located on the pixel (x + 1, y + 1). Therefore, the irradiation amount distributed to the beam B is obtained from the irradiation amount of each pixel and the ratio of the overlapping area, and the irradiation amount distributed from each pixel is summed to calculate the corrected irradiation amount of the beam B.

  For example, the ratio of the area where the beam B overlaps the pixel at the coordinates (x, y) (= overlap area / 1 pixel area) is A10, and the irradiation amount of the pixel at the coordinates (x, y) is D10. . Similarly, the ratio of the area where the beam B overlaps the pixel at the coordinates (x, y + 1), (x + 1, y), (x + 1, y + 1) is A11, A12, A13, and the coordinates (x, y + 1), (x + 1). , Y) and (x + 1, y + 1) are denoted by D11, D12, and D13, respectively. In this case, the corrected irradiation amount of the beam B is obtained by D10 × A10 + D11 × A11 + D12 × A12 + D13 × A13. In this way, the corrected irradiation amount of each beam is calculated.

  A case in which a shot is performed while shifting by サ イ ズ of the irradiation area size is taken as an example. FIGS. 8A to 8D show a case where the shot is simply shifted by １ ／ of the irradiation area size. Since the boundary of the irradiation area 34 and the boundary of the pixel 40 do not match, in each of the shots of FIGS. 8A to 8D, the positional relationship between the beam and the pixel 40 differs, and The way of straddling is different. Therefore, the distribution ratio of the irradiation amount to the adjacent pixels differs between shots. That is, the dose correction maps that define the distribution ratio of the dose to the adjacent pixels are different from each other in FIGS. 8A to 8D, and the calculation cost of the correction process increases.

  Therefore, in the present embodiment, the shot position (deflection coordinates) is adjusted so that the boundary of the irradiation area 34 matches the boundary of the pixel 40. 9A to 9D show an example of shot position adjustment according to the present embodiment. FIGS. 9A and 9B are the same as FIGS. 8A and 8B. In this example, in the shot shown in FIG. 9C, the boundary of the irradiation region 34 and the boundary of the pixel 40 are matched. By the position adjustment, for example, the end on the + x side of the irradiation area of the shot in FIG. 9A and the end on the −x side of the irradiation area of the shot in FIG. 9C overlap.

  By such position adjustment, in FIGS. 9A and 9C, the positional relationship between each beam and the pixel 40 (how to cross over the adjacent pixel) becomes the same, and the distribution ratio of the irradiation amount to the adjacent pixel is reduced. Will be the same. Therefore, FIGS. 9A and 9C can use a common dose correction map. Similarly, FIGS. 9B and 9D can use a common dose correction map. That is, if a combination of two correction maps, the irradiation amount correction map in FIG. 9A and the irradiation amount correction map in FIG. 9B, is created, the combination can be used repeatedly thereafter. Since the common correction map can be used repeatedly, the calculation cost of the correction processing can be reduced. In the data area determination step S102, the deflection coordinate adjustment step S104, and the correction map creation step S106, such a correction map creation process is performed.

  The steps from the data area determination step S102 to the correction map creation step S106 are preferably executed as pre-processing for executing the drawing processing.

  Before performing the drawing process, the beam size of each pixel when the multi-beam is irradiated onto the mask substrate 101 surface is measured in advance, and the irradiation region size is obtained. A measurement substrate to which a resist (not shown) is applied is placed on the stage 105 and irradiated with a multi-beam, so that an irradiation area size can be obtained. The beam size data and the irradiation area size data are stored in the storage device 144.

  In the data area determination step S102, the data area determination unit 50 determines a data area corresponding to the irradiation area 34 among the pixel data using the irradiation area size data. For example, within the stripe region 32, the size of the data region is set to be smaller than the actual irradiation region size, and the boundary of the data region is matched (matched) with the boundary of the closest pixel 40. For example, a hatched portion in FIG. 10 is a data area.

  In the deflection coordinate adjustment step S104, the deflection coordinate adjustment unit 52 adjusts the deflection coordinates based on the boundary of the data area specified in step S102 so that the boundary of the irradiation area 34 matches the boundary of the pixel 40. For example, as shown in FIG. 11, the deflection coordinates are adjusted in the −x direction.

  In the correction map creation step S106, a correction map for allocating the dose to adjacent pixels is created. When performing a shot while shifting the irradiation area by １ ／, two types of correction maps are created. Similarly, when a shot is performed while shifting by １ ／ of the irradiation area size, three types of correction maps that are repeatedly used are created. When performing a shot while shifting the irradiation area size (1 time), one type of correction map is created. The created correction map is stored in the storage device 146.

  In order to reduce resources by reducing the number of correction maps to be created, for example, even in the shots shown in FIGS. 9B and 9D, shot positions are set so that the boundary of the irradiation area 34 and the boundary of the pixel 40 match. May be adjusted. As a result, in all shots, the positional relationship between each beam and the pixel 40 (how to cross over adjacent pixels) becomes the same, and a common irradiation amount correction map can be used. Similarly, in the case where shots are performed while being shifted by ３ of the irradiation area size, the shot position of each shot is adjusted so that a common irradiation amount correction map can be used for all shots. Forty boundaries may be matched. Alternatively, the shot position may be adjusted so that two types of correction maps are used.

  Thus, after the correction map is created as the pre-processing, the actual drawing processing is started. As described above, first, in the drawing data acquisition step S202, the drawing data is read from the storage device 140 for each stripe region, and subsequently, in the shot data creation step S204, the beam irradiation amount for each pixel is calculated.

  Next, in the correction step S206, the correction unit 58 distributes the dose of each pixel to adjacent pixels based on the dose distribution ratio specified in the correction map. The correction unit 58 calculates the corrected dose of each pixel (beam) by adding the doses distributed from the adjacent pixels. By correcting the irradiation amount of each pixel in this manner, pixel data is reconstructed.

  Further, after reconstructing the pixel data, the correcting unit 58 adjusts the irradiation amount to the adjacent pixels in order to correct the positional deviation and the dimensional deviation of the pattern formed by the beam having the positional deviation due to the distortion of the electron beam. May be distributed. For example, as shown in FIG. 12, the beam corresponding to the pixel at the coordinates (x, y) has the coordinates (x, y + 1), (x + 1, y), (x) in addition to the pixel at the coordinates (x, y). In the case of being located on the pixel of (x + 1, y + 1), the irradiation amount of the pixel at the coordinates (x, y) is allocated to a pixel adjacent to the opposite side to the overlapping pixel according to the ratio of the overlapping area. For example, the irradiation amount according to the area ratio overlapping the pixel at the coordinate (x, y + 1) is allocated to the pixel at the coordinate (x, y-1). Then, the doses assigned from the adjacent pixels are added to obtain a corrected dose.

  The number of beams corresponding to one pixel is not necessarily limited to one, and may be two or more. Further, there may be a case where the irradiation amount of the beam corresponding to one pixel is not allocated to another beam.

  In the drawing step S208, the drawing unit 150 draws a pattern on the mask substrate 101 using the multi-beam so that each beam is irradiated on the corresponding pixel by the amount of the corrected irradiation. The drawing control unit 60 converts the corrected irradiation amount into the irradiation time, rearranges the shots according to the drawing sequence, and outputs irradiation time data to the deflection control circuit 130. The deflection control circuit 130 controls the blanker of the blanking plate 204 and the amount of deflection of the deflector 208 for each shot based on the irradiation time data. The drawing control unit 60 outputs the deflection coordinates adjusted by the deflection coordinate adjustment unit 52 to the deflection control circuit 130. Thereby, the deflection amount of the deflector 208 is controlled so that the boundary of the irradiation region of the multi-beam coincides with the boundary of the pixel.

  As described above, according to the present embodiment, even when the beam size changes, the irradiation amount of the pixel is distributed and the irradiation amount of each beam is corrected, so that it is possible to prevent the deterioration of the drawing accuracy. Further, the data area is determined (limited) so that the boundary of the irradiation area 34 and the boundary of the pixel 40 coincide with each other, and the deflection coordinates are adjusted to match this boundary. It can be shared between shots, and the time and resources required for the correction map creation processing can be reduced.

  In the above embodiment, a plurality of sets of at least one correction map used repeatedly may be created according to global position dependency on the mask substrate 101 or the like.

  In the above embodiment, an example is described in which two correction processes are performed, i.e., correction of the irradiation amount for reconstructing the pixel data and correction of the irradiation amount for correcting the positional shift and the dimensional shift of the formed pattern. Although described, these may be performed together in one correction process. For example, the area (dose) and the center of gravity are matched between an ideal shot (a calculated shot before the dose correction) and an actual shot (a shot after the dose correction), so that the corrected dose is Calculate.

The description will be given focusing on the pixel 40A shown in FIG. This pixel 40A, it is assumed that overlapping three beams B1, B2, B3 located displaced with changes in the beam size, the dose of each beam and _{D 1, D 2, D 3} . At this time, the correction dose D of the pixel 40A is calculated so that the following relational expression holds.

  Formulas similar to the above are established for the other pixels, and the corrected dose of each pixel is calculated so that a plurality of formulas hold. By correcting the irradiation amount so that the area (irradiation amount) and the center of gravity match each other, it is possible to reconstruct the pixel data and to correct the positional deviation and the dimensional deviation of the pattern.

  In the data area determination step S102 of the above embodiment, the data area determination unit 50 may determine the data area to be larger than the size of the irradiation area 34. For example, as shown in FIG. 14A, the data area DR is made larger than the irradiation area 34 in the + x direction and the + y direction (rightward and upward in the figure). At this time, since shots at the boundary portions outside the irradiation area 34 on the + x side and + y side, which are indicated by hatched portions in FIG. 14B, are separately required, the shot data creation section 56 Complement. As the shot of the supplemented shot data, as shown in FIG. 14C, a beam that performs a shot in a region in the −x direction and the −y direction (lower left in the drawing) is used.

  In the present embodiment, the correction of the irradiation amount and the like is performed using the correction map. However, the correction calculation may be performed using a correction formula or the like without necessarily using the map.

  The writing apparatus 100 is configured such that, during irradiation of the multi-beam on the mask substrate 101 disposed on the movable XY stage 105, each beam is irradiated so that the irradiation target pixel of each beam does not shift due to the movement of the XY stage 105. Irradiation of each beam is performed while performing a tracking operation following the stage movement. When one or more shots are completed, the tracking operation is reset, each beam is turned back, the deflection position is shifted to the next irradiation target pixel, and then each beam is irradiated while performing the tracking operation in the same manner. .

  In the conventional tracking control, tracking is continued from time t = 0 to time t = T at a position A0 on the substrate, as shown in FIG. During time T, the stage moves by distance L. By resetting the tracking at time t = T, the beam is turned back in the direction opposite to the stage moving direction. After the elapse of the settling time Ts of the DAC amplifier, the next tracking is started for the position A1.

  For the position A1, tracking is continued from time t = T + Ts to t = 2T + Ts. During this time, the stage moves by the distance L. The beam is turned back by resetting the tracking at the time point of t = 2T + Ts, and after the settling time Ts of the DAC amplifier has elapsed, the next tracking is started for the position A2. Thereafter, such an operation is repeated.

  In the conventional tracking operation, the distance between shots (for example, the distance from the position A0 to the position A1, the distance from the position A1 to the position A2) is constant, and the tracking reset distance (the distance to swing back the beam) is also constant. ing. On the other hand, in the above-described embodiment, the shot position (deflection coordinates) is adjusted so that the boundary of the irradiation area 34 coincides with the boundary of the pixel 40. The distance may not be constant.

  The drawing apparatus 100 obtains the beam deflection coordinates P and the corrected irradiation amount adjusted so as to associate the boundary of the irradiation area 34 with the boundary of the pixel 40, and determines shot data. The deflection control circuit 130 reads the shot data, calculates the tracking reference position P-L0 from the deflection coordinates P and the stage position L0 at the start of tracking, and starts the tracking operation.

  To calculate the tracking reference position P-L0, an offset term may be added in order to use the entire irradiation area 34 and use the tracking range widely.

  After the adjustment of the deflection coordinates, as shown in FIG. 16 (a), the deviation between the pixel mesh (dashed line in the figure) and the beam mesh (solid line in the figure) is large, and the pixel 40B whose pixel center is not included in the beam mesh is shown. Can occur. When a desired dose is given to the pixel 40B by the beam B4, the dose needs to be extremely large, and the drawing time per shot becomes longer. Drawing on the mask substrate 101 includes a large number of shots, which greatly affects the total drawing time.

  Therefore, when the displacement between the pixel mesh and the beam mesh is equal to or more than a predetermined amount, for example, when a pixel 40B whose pixel center is not included in the beam mesh occurs, as shown in FIG. It is preferable to add a shot such that the shot fits within the beam mesh. The total drawing time is shorter when one shot is added than when the drawing time per one shot is lengthened.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. Various inventions can be formed by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.

Reference Signs List 20 Multi-beam 22 Hole 32 Stripe region 50 Data region determination unit 52 Deflection coordinate adjustment unit 54 Correction map creation unit 56 Shot data creation unit 58 Correction unit 60 Drawing control unit 100 Drawing device 101 Mask substrate 102 Electronic lens barrel 103 Drawing room 105 XY Stage 110 Control computer 112 Memory 130 Deflection control circuit 139 Stage position detector 140, 142, 144, 146 Storage device 150 Drawing unit 160 Control unit 200 Electron beam 201 Electron gun 202 Illumination lens 203 Aperture member 204 Blanking plate 205 Reduction lens 206 Limiting aperture member 207 Objective lens 208 Deflector 210 Mirror

Claims (9)

A data area is determined based on a boundary between pixels obtained by dividing the drawing area of the substrate into a mesh shape, an irradiation area of the multi-charged particle beam, and a boundary of the stripe area obtained by dividing the drawing area by a predetermined width in a predetermined direction. A data area determination unit;
A deflection coordinate adjustment unit that adjusts the deflection coordinates of the multi-charged particle beam so as to correspond to the boundary of the pixel and the boundary of the irradiation area,
Based on the positional relationship between each of the multi-charged particle beams and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data is set to one or more beams. And a correction unit for calculating a correction dose by adding the split dose in each of the beams,
A drawing unit that deflects a multi-charged particle beam based on the adjusted deflection coordinates, and irradiates a beam of the corrected irradiation amount to draw a pattern,
Equipped with a,
The correction unit, for each pixel in the data area, the correction dose is calculated using a correction map that defines a ratio of distributing the dose of the beam corresponding to the pixel to surrounding beams, multi charged particle beam drawing apparatus that. Wherein the correction unit, for each pixel, multi according the position of the center of gravity of the pixel, and a dose and the center of gravity position of the beam corresponding to the pixel, to claim 1, characterized in that to calculate the corrected dose Charged particle beam drawing equipment. When the data area determination unit determines that the data area is larger than the irradiation area of the multi-charged particle beam, the data area determination unit complements shot data corresponding to a location located outside the irradiation area in the data area. The multi-charged particle beam drawing apparatus according to claim 1 or 2 , wherein: A stage on which the substrate is placed and moved,
A plurality of openings are formed, an aperture member that forms a multi-charged particle beam by passing a charged particle beam through the plurality of openings,
Of the multi-charged particle beam, a blanking plate in which a plurality of blankers for switching on / off the corresponding beam, respectively, are arranged,
A deflector that deflects the beams beam-on by the plurality of blankers together to follow the movement of the stage,
The beam is deflected to a first drawing position, and tracking control is performed so that the beam irradiation position follows the movement of the stage during drawing for a predetermined time. After the predetermined time has elapsed, the beam deflection is reset and the beam is moved in the stage movement direction. A deflection control unit that controls the deflector to return to the opposite direction,
Further comprising
After the drawing at the first drawing position, the deflection control unit performs drawing and tracking control by deflecting the beam to the second drawing position. After drawing at the second drawing position, the beam is subjected to the third drawing. multi charged particle beam drawing apparatus according to any one of claims 1 to 3, characterized in that deflects to a position for drawing and tracking control. If positional deviation between the beam corresponding to the pixel and the pixel is not less than a predetermined amount, the multi-charged particles according to any one of claims 1 to 4, characterized in that to add a shot for illuminating the pixel Beam drawing device.   A data area is determined based on a boundary between pixels obtained by dividing the drawing area of the substrate into a mesh shape, an irradiation area of the multi-charged particle beam, and a boundary of the stripe area obtained by dividing the drawing area by a predetermined width in a predetermined direction. A data area determination unit;
  A deflection coordinate adjustment unit that adjusts the deflection coordinates of the multi-charged particle beam so as to correspond to the boundary of the pixel and the boundary of the irradiation area,
  Based on the positional relationship between each of the multi-charged particle beams and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data is set to one or more beams. And a correction unit for calculating a correction dose by adding the split dose in each of the beams,
  A drawing unit that deflects a multi-charged particle beam based on the adjusted deflection coordinates, and irradiates a beam of the corrected irradiation amount to draw a pattern,
  With
  If the displacement between the pixel and the beam corresponding to the pixel is a predetermined amount or more, add a shot for irradiating the pixel,
  A multi-charged particle beam drawing apparatus, wherein a shot is added when the center of the pixel is not included in a beam corresponding to the pixel. A data area is determined based on a boundary between pixels obtained by dividing the drawing area of the substrate into a mesh shape, an irradiation area of the multi-charged particle beam, and a boundary of the stripe area obtained by dividing the drawing area by a predetermined width in a predetermined direction. Process and
Adjusting the deflection coordinates of the multi-charged particle beam so as to correspond to the boundaries of the pixels and the boundaries of the irradiation area,
Based on the positional relationship between each of the multi-charged particle beams and the pixels in the data area, the irradiation amount of the beam corresponding to the pixels in the data area calculated based on the drawing data is set to one or more beams. And calculating a corrected dose by adding the split dose in each of the beams,
A step of deflecting a multi-charged particle beam based on the adjusted deflection coordinates and irradiating a beam of the corrected dose to draw a pattern,
Equipped with a,
A multi-charged particle beam, wherein the correction dose is calculated using a correction map that defines a ratio of distributing a dose of a beam corresponding to the pixel to surrounding beams for each pixel in the data area. Drawing method. Performing a tracking control for causing the irradiation position of the multi-charged particle beam to follow the movement of the stage on which the substrate is mounted, and after a predetermined time elapse, resetting the beam deflection and returning the beam to the direction opposite to the stage moving direction. Further comprising
The beam is deflected to a first writing position to perform writing and tracking control. After writing at the first writing position, the beam is deflected to a second writing position to perform writing and tracking control. 8. The multi-charged particle beam writing method according to claim 7 , wherein after writing at the position, the beam is deflected to a third writing position to perform writing and tracking control. If positional deviation between the beam corresponding to the pixel and the pixel is not less than a predetermined amount, the multi-charged particle beam writing method according to claim 7 or 8, characterized in adding a shot for illuminating the pixel .

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