JP2012015244A - Device and method for drawing charged particle beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for drawing a charged particle beam which reduces the drawing time when performing the multiple drawing.SOLUTION: A drawing device 100 includes: a division part 50 which virtually divides a chip region in which a pattern is formed into a plurality of small areas; a multiplex degree computing/setting part 64 which sets the multiplex degree for drawing the pattern in the small areas for every small area so that the multiplex degree different from the others is set to at least a part of the plurality of the small areas obtained by virtual division of the chip region; and a drawing part 150 which draws the pattern in the small areas with the multiplex degree set for every small area using the charged particle beam.

Description

  The present invention relates to a charged particle beam drawing apparatus and a charged particle beam drawing method, and for example, relates to a drawing method and apparatus used for multiple drawing using an electron beam.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

FIG. 7 is a conceptual diagram for explaining the operation of a conventional variable shaping type electron beam drawing apparatus.
The variable shaped electron beam (EB) drawing apparatus operates as follows. In the first aperture 410, a rectangular opening for forming the electron beam 330, for example, a rectangular opening 411 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 330 having passed through the opening 411 of the first aperture 410 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 of the first aperture 410 is deflected by the deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and passes through a predetermined range. The sample 340 mounted on a stage that continuously moves in one direction (for example, the X direction) is irradiated. That is, the drawing area of the sample 340 mounted on the stage in which the rectangular shape that can pass through both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is continuously moved in the X direction. Drawn on. A method of creating an arbitrary shape by passing both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method (VSB method).

  In such electron beam drawing, a multiple drawing method is generally adopted in which drawing is performed by overlapping drawing patterns a plurality of times. The multiple drawing method is effective in improving the pattern joining accuracy at the boundary between the stripe regions where the chip region is virtually divided, and in reducing the heating (charging) effect at the time of drawing. For this reason, conventionally, the number of times of drawing (multiplicity) is set for each chip to be drawn, and drawing is performed with the set multiplicity.

  In electron beam drawing, dimensional variations due to proximity effects or the like are corrected by increasing or decreasing the dose. Therefore, the irradiation amount often varies depending on the drawing position. For this reason, the above-described heating (charging) effect can be reduced even with the maximum irradiation amount, and the multiplicity is determined in advance for each chip and input to the drawing apparatus so that the connection accuracy is satisfied.

  In general, a pattern of a plurality of chips is drawn on a mask that is one of the samples, and the drawing conditions are often different depending on the chip. For example, a certain chip is drawn once (multiplicity = 1). Another chip is drawn by multiple drawing (for example, multiplicity = 2) (see, for example, Patent Document 1). Conventionally, in an electron beam drawing apparatus, when drawing a pattern of a plurality of chips on a mask, chips having the same drawing conditions laid out within a certain range are grouped together to form a drawing group, and drawing is performed for each drawing group. It was. As a result, while drawing within one drawing group, drawing is performed under the same drawing condition (multiplicity).

  As the multiplicity increases, the drawing time increases accordingly. With recent miniaturization of patterns, it is desired to shorten the drawing time. Therefore, it is desired to shorten the drawing time when performing such multiple drawing.

Japanese Patent Laid-Open No. 11-274036

  As described above, while it is desired to shorten the drawing time, it is desirable to solve such a problem even when performing multiple drawing. However, conventionally, a method for sufficiently solving such a problem has not been established.

  In view of the above, an object of the present invention is to overcome the above-described problems and reduce the drawing time when multiple drawing is performed.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
A dividing unit that virtually divides a chip area to be patterned into a plurality of small areas;
Setting for setting the multiplicity for drawing a pattern in each small area so that a different multiplicity is set for at least a part of the plurality of small areas obtained by virtually dividing the chip area. And
For each small region, using a charged particle beam, a drawing unit that draws a pattern in the small region with a set multiplicity,
It is provided with.

  With such a configuration, areas with different multiplicity can be set in one chip. Therefore, since the same multiplicity is not set as in the conventional case, in the low multiplicity region, it is possible to shorten the drawing time corresponding to the reduction in the number of times of drawing.

Further, the apparatus further comprises a dose map calculation unit for calculating a dose map in which the dose is defined,
It is preferable that the setting unit is configured to set a multiplicity for drawing a pattern in the small region using each dose defined in the dose map.

In addition, it further includes a determination unit that determines whether each dose defined in the dose map is larger than a threshold value,
The setting unit is preferably configured to set the multiplicity so that the irradiation amount per drawing does not become larger than the threshold value.

  In addition, as a plurality of small regions in which multiplicity is set, a plurality of shot regions irradiated with a charged particle beam, a plurality of subfield regions composed of at least one shot region, and one is a plurality of subfields It is preferable to use one of a plurality of stripe regions constituted by regions.

The charged particle beam drawing method of one embodiment of the present invention includes:
Virtually dividing the pattern formed chip region into a plurality of small regions;
A step of setting a multiplicity for drawing a pattern in the small region for each small region so that a multiplicity different from the others is set in at least a part of the plurality of small regions obtained by virtually dividing the chip region When,
For each small region, using a charged particle beam, drawing a pattern in the small region with a set multiplicity,
It is provided with.

  According to the present invention, the drawing time can be reduced even when multiple chips are drawn.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. FIG. 4 is a flowchart showing main steps of the drawing method according to Embodiment 1. 6 is a conceptual diagram for explaining a stripe layer and a drawing procedure in Embodiment 1. FIG. FIG. 6 is a conceptual diagram for explaining an SF layer and a drawing procedure in the first embodiment. 3 is a conceptual diagram for explaining a shot layer and a drawing procedure in Embodiment 1. FIG. 6 is a diagram illustrating an example of a determination region mesh in the first embodiment. FIG. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus.

  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, and a beam using charged particles such as an ion beam may be used. Further, a variable shaping type drawing apparatus will be described as an example of the charged particle beam apparatus.

  As described above, conventionally, the same multiplicity has been set uniformly in chips to be drawn. However, in order to reduce the heating effect, it is only necessary to increase the drawing multiplicity only in the region where the irradiation amount is large. Therefore, hereinafter, in the embodiment, regions of different multiplicity are set in a chip to be drawn. As a result, in the low multiplicity region, the drawing time can be shortened as the number of drawing times decreases.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The drawing apparatus 100 is an example of a charged particle beam drawing apparatus. In particular, it is an example of a variable shaping type drawing apparatus. The drawing unit 150 includes an electron column 102 and a drawing chamber 103. In the electron column 102, there are an electron gun 201, an illumination lens 202, a first aperture 203, a projection lens 204, a deflector 205, a second aperture 206, an objective lens 207, a main deflector 208, and a sub deflector 209. Has been placed. An XY stage 105 is disposed in the drawing chamber 103. On the XY stage 105, a sample 101 such as a mask to be drawn at the time of drawing is arranged. The sample 101 includes an exposure mask for manufacturing a semiconductor device. Further, the sample 101 includes mask blanks on which nothing has been drawn yet.

  The control unit 160 includes a control computer unit 110, a memory 111, a control circuit 120, and storage devices 140, 142, and 144 such as a magnetic disk device. The control computer unit 110, the memory 111, the control circuit 120, and the storage devices 140, 142, and 144 such as a magnetic disk device are connected to each other via a bus (not shown).

  In the control computer unit 110, a dividing unit 50, a pattern density calculating unit 52, an irradiation amount density calculating unit 54, an irradiation amount calculating unit 56, a multiplicity setting unit 60, and a drawing data processing unit 66 are arranged. In the multiplicity setting unit 60, a determination unit 58, a multiplicity calculation unit 62, and a multiplicity calculation / setting unit 64 are arranged. The dividing unit 50, the pattern density calculating unit 52, the dose density calculating unit 54, the dose calculating unit 56, the multiplicity setting unit 60, and the drawing data processing unit 66 may be configured by hardware such as an electric circuit. In addition, it may be configured by software such as a program for executing these functions. Alternatively, it may be configured by a combination of hardware and software. Similarly, the determination unit 58, the multiplicity calculating unit 62, and the multiplicity calculating / setting unit 64 may be configured by hardware such as an electric circuit or software such as a program that executes these functions. May be. Alternatively, it may be configured by a combination of hardware and software. The division unit 50, the pattern density calculation unit 52, the dose density calculation unit 54, the dose calculation unit 56, the multiplicity setting unit 60, the drawing data processing unit 66, the determination unit 58, the multiplicity calculation unit 62, and the multiplicity Information input / output to / from the calculation / setting unit 64 and information being calculated are stored in the memory 111 each time. In particular, the drawing data processing unit 66 is preferably composed of a plurality of CPUs and a plurality of memories (not shown) because the data processing amount can be enormous.

  Chip data serving as layout data (drawing data) is input from the outside of the apparatus and stored in the storage device 140. The chip is composed of a plurality of graphic patterns.

  In the storage device 142, information necessary for setting the multiplicity in the first embodiment is input from the outside of the device and stored. For example, multiplicity information indicating the multiplicity N necessary to maintain the necessary connection accuracy between stripes, subfields (SF), or shots is stored. Furthermore, a dose threshold A required for determining the required multiplicity is stored. Furthermore, determination area information indicating a determination area for determining the required multiplicity is stored. Further, multiplicity variable area information indicating a multiplicity variable area which is a unit area when the multiplicity is set variably is stored. Further, it indicates whether or not to permit reduction to a multiplicity lower than the multiplicity defined in the multiplicity information within a range where the irradiation dose per drawing does not become larger than the dose threshold A. The availability flag is stored.

  Here, FIG. 1 shows a configuration necessary for explaining the first embodiment. The drawing apparatus 100 may normally have other necessary configurations. For example, the main deflector 208 and the sub deflector 209, which are the main and sub two-stage deflectors, are used for position deflection. However, the position deflection may be performed by a single stage deflector.

  FIG. 2 is a flowchart showing main steps of the drawing method according to the first embodiment. In FIG. 2, the drawing method according to the first embodiment includes a mesh dividing step (S102), a pattern density calculating step (S104), an irradiation density calculating step (S106), and an irradiation amount calculating step (irradiation amount map creating step). ) (S106), a multiplicity setting step (S108), a shot data generation step (S116), and a drawing step (S118). In the multiplicity setting step (S108), a series of steps such as a determination step (S110), a determination region multiplicity calculation step (S112), and a variable region multiplicity calculation / setting step (S114) are performed as internal processes. .

  FIG. 3 is a conceptual diagram for explaining a stripe layer and a drawing procedure in the first embodiment. FIG. 3 shows a case where, for example, a stripe region 20 is set as the multiplicity variable region. In the drawing apparatus 100, the drawing area of the sample 101 is virtually divided into a plurality of strip-shaped stripe areas 20. FIG. 3 shows a case where, for example, one chip indicated by the chip area 10 is drawn on the sample 101. Of course, a plurality of chips may be drawn on the sample 101. The width of the stripe region 20 is divided by a width that can be deflected by the main deflector 208. When drawing on the sample 101, the XY stage 105 is continuously moved in the x direction, for example. The electron beam 200 irradiates one stripe region 20 while continuously moving in this way. The movement of the XY stage 105 in the X direction is a continuous movement, and at the same time, the main deflector 208 causes the shot position of the electron beam 200 to follow the stage movement. Further, the drawing time can be shortened by continuously moving. When drawing of one stripe region 20 is completed, the XY stage 105 is stepped in the y direction, and the next stripe region 20 is drawn in the x direction (in this case, the opposite direction). The moving time of the XY stage 105 can be shortened by making the drawing operation of each stripe region 20 meander.

  In the example of FIG. 3, for example, only the second stripe region 20 from the bottom requires multiplicity N = 2 (drawing twice), and the other stripe regions 20 have multiplicity N = 1 (one time). (Drawing) shows a good case. In such a case, in the first embodiment, all the stripe regions 20 are drawn as the first stripe layer L1. In the second stripe layer L2, only the second stripe region 22 from the bottom is drawn. In this way, even within a chip with the same drawing conditions or within the same drawing group with the same drawing conditions, a low multiplicity can be set by increasing or decreasing the multiplicity locally in some stripe regions as necessary. This can reduce the number of times the area is drawn. Conventionally, if there is even one area that requires multiplicity N = 2 (two times of drawing), all stripe regions 20 are drawn with multiplicity N = 2 (two times of drawing). Thus, by reducing the multiplicity for unnecessary areas and conversely increasing the multiplicity for necessary areas, it is possible to maintain the connecting accuracy between stripes and reduce the heating effect while shortening the drawing time. The drawing order may be that after drawing all the stripe regions 20 of the first layer, the stripe region 22 of the second layer may be drawn, or the stripe region 20 is drawn in order from the bottom, and the second region from the bottom. For the second stripe region 20, the drawing for the second layer may be continued after the drawing for the first layer.

  FIG. 4 is a conceptual diagram for explaining the SF layer and the drawing procedure in the first embodiment. FIG. 4 shows a case where, for example, the SF area 30 is set as the multiplicity variable area. Each stripe region 20 is virtually divided into a plurality of small regions (SF: subfield) having a square mesh shape, for example. The size of the SF region 30 is a size that can be deflected by the sub deflector 209. The deflection area to be divided is the deflection area having the smallest SF.

  Here, in the example of FIG. 4, for example, only the third and fourth SF areas 30 from the bottom of the first column need multiplicity N = 2 (2 times drawing), and in the other SF areas 30, multiplicity N = This shows a case where 1 (one-time drawing) is sufficient. In such a case, in the first embodiment, all the SF areas 30 are drawn as the first SF layer L1. In the second SF layer L2, only the third and fourth SF areas 32 from the bottom of the first column are drawn. In this way, even if the drawing conditions are the same in the chip or the drawing conditions are the same drawing group, the multiplicity is set to a low multiplicity by locally increasing / decreasing the multiplicity of some SF areas as necessary. This can reduce the number of times the area is drawn. Conventionally, if there is an area where multiplicity N = 2 (drawing twice) is required, all the SF areas 30 are drawn with multiplicity N = 2 (drawing twice). Thus, by reducing the multiplicity for unnecessary areas and conversely increasing the multiplicity for necessary areas, the drawing time can be shortened while maintaining the connection accuracy between SFs and reducing the heating effect. The drawing order is drawn in order from the left column to the right column, and in each column, for example, the drawing is done in order from the bottom to the top. In the example of FIG. 4, the drawing is performed in order from the lower SF of the first column upward (toward the y direction), and the drawing of the first layer of the first column (in the order of 1 to 6 in FIG. 4) is completed. Later, the second layer of the first column is drawn (in the order of 7 and 8 in FIG. 4). Then, after finishing the first column, the SFs in the second column are similarly drawn in order.

  FIG. 5 is a conceptual diagram for explaining a shot layer and a drawing procedure in the first embodiment. FIG. 5 shows a case where a shot area indicated by a graphic pattern 40 or the like is set as the multiplicity variable area, for example. Within each SF region 30, an electron beam 200 variably shaped to a desired shape and size is shot at each figure position by the sub deflector 209. The example of FIG. 5 shows a case where a square graphic pattern 40 and a rectangular graphic pattern 41 are shot.

  Here, in the example of FIG. 5, for example, only the graphic pattern 40 requires multiplicity N = 2 (draw twice), and the other graphic pattern 41 may have multiplicity N = 1 (draw once). Show. In such a case, in the first embodiment, all the graphic patterns 40 and 41 are drawn as the first shot layer L1. In the second shot layer L2, only the graphic pattern 42 is drawn at the position of the graphic pattern 40. In this way, even if the drawing conditions are within the same chip or within the same drawing group, only a part of the shots can be set to a low multiplicity by locally increasing or decreasing the multiplicity as necessary. The number of shot area drawing operations can be reduced. Conventionally, if there is an area where multiplicity N = 2 (drawing twice) is required, all shots are drawn with multiplicity N = 2 (double drawing). However, as in the first embodiment, By reducing the multiplicity for unnecessary regions and conversely increasing the multiplicity for necessary regions, for example, the drawing time can be shortened while maintaining the joining accuracy between shots and reducing the heating effect. The drawing order is not particularly specified. For example, after drawing the graphic pattern 40, the graphic pattern 41 is drawn successively, and then the graphic pattern 42 is drawn.

  Hereinafter, a method of setting different multiplicity depending on the area in the chip will be described along the steps.

  As a mesh dividing step (S102), the dividing unit 50 reads the determination area information from the storage device 142, and converts the chip area to be patterned into a plurality of mesh areas (small areas: determination) with the size defined in the determination area information. Area). Further, the dividing unit 50 reads the multiplicity variable area information from the storage device 142, and divides the chip area to be patterned into a plurality of mesh areas (small areas: multiplicity variable areas) with a size defined in the multiplicity variable area. ). The multiplicity variable region includes a plurality of shot regions indicated by the graphic pattern 40 or the like irradiated with the electron beam 200 described above, a plurality of SF regions composed of at least one shot region, and one of the plurality of SF regions 30. At least one of the plurality of stripe regions 20 to be configured is used. In other words, the multiplicity variable region may be a combination of the SF region 30 and the stripe region 20. As will be described later, the multiplicity is newly set for each multiplicity variable region.

  FIG. 6 is a diagram illustrating an example of the determination region mesh in the first embodiment. The size of the determination area 12 divided into meshes may be the same size as the SF, for example, or may be larger or smaller than the SF. For example, the image is divided into mesh regions having a size of 10 μm.

  As the pattern density calculation step (S104), the pattern density calculation unit 52 reads the chip data from the storage device 140, and calculates the proximity effect density of the pattern in the mesh region for each proximity effect mesh having a predetermined size. Here, the proximity effect density U (x) is defined as a value obtained by convolving and integrating the distribution function g (x) with the pattern area density ρ (x) in the proximity effect mesh in a range equal to or greater than the influence range of the proximity effect. The proximity effect mesh preferably has a size of, for example, about 1/10 of the influence range of the proximity effect, and for example, a size of about 1 μm is preferable. x is a vector indicating the position.

As the dose density calculation step (S106), the dose density calculation unit 54 calculates the dose (unit dose density) per unit area. Here, the dimensional variation due to factors such as proximity effect, fogging, or loading effect is corrected by the dose. Therefore, the irradiation amount with the dimensional variation corrected is calculated. For example, the dose density D (x, U) corrected for the proximity effect is the proximity effect corrected dose Dp (η (x), U (x) depending on the reference dose Dbase and the proximity effect correction coefficient η (x). )) Can be obtained by the following equation (1).
(1) D (x, U) = Dbase · Dp (η (x), U (x))

  As an irradiation amount calculation step (irradiation amount map creation step) (S106), the irradiation amount calculation unit 56 calculates an irradiation amount in each determination region 12. Here, it can be calculated by multiplying the figure pattern area arranged in each determination region 12 by the dose density D (x, U). Then, the dose calculation unit 56 calculates and creates a dose map in which the dose is defined for each determination region 12 using the determination region 12 as a unit region. The dose calculation unit 56 is an example of a dose map calculation unit.

  In the multiplicity setting step (S108), the multiplicity setting unit 60 sets a multiplicity different from the others in at least a part of a plurality of multiplicity variable regions (small regions) in which the chip region 10 is virtually divided. In addition, a multiplicity for drawing a pattern in the multiplicity variable area is set for each multiplicity variable area. Further, the multiplicity setting unit 60 sets the multiplicity for drawing the pattern in the multiplicity variable region using each irradiation dose defined in the irradiation dose map. In particular, the multiplicity of each multiplicity variable region is set so that the irradiation amount per drawing does not become larger than the irradiation amount threshold A (threshold). Specifically, it operates as follows.

  As a determination step (S108), the determination unit 58 reads the dose threshold A from the storage device 142, and the dose D of the determination region 12 defined in the dose map is determined for each determination region 12. It is determined whether it is larger than the threshold value A (threshold value).

  As the determination area multiplicity calculation step (S112), the multiplicity calculation unit 62 determines the multiplicity N ′ (however, the irradiation amount per drawing does not become larger than the irradiation amount threshold A for each determination area 12). , N ′> 1). When D> A in the determination step (S108), the multiplicity calculation unit 62 first multiplicity N ′ that is the minimum multiplicity within a range in which the irradiation amount per drawing does not become larger than the irradiation amount threshold A. Is calculated. When D> A is not satisfied in the determination step (S108), the multiplicity calculation unit 62 calculates multiplicity N ′ = 1.

  As the variable area multiplicity calculation / setting step (S114), the multiplicity calculation / setting unit 64 reads the multiplicity variable area information from the storage device 142, and for each multiplicity variable area indicated in the multiplicity variable area information, The maximum value N ″ of the multiplicity N ′ calculated in the determination area that is located in the multiplicity variable area or overlaps the multiplicity variable area is calculated. The multiplicity information is read, and the multiplicity maximum value N ″ is compared with the multiplicity N indicated by the multiplicity information. When the multiplicity maximum value N ″ is smaller than the multiplicity N, the multiplicity calculation / setting unit 64 reads the availability flag from the storage device 142, and when the multiplicity may be lowered based on the availability flag, the multiplicity is determined. The multiplicity of the variable area is set as N ″. The multiplicity of the multiplicity variable region is set to N by the availability flag or when the flag is not defined and it is not permitted to reduce the multiplicity. When the multiplicity maximum value N ″ is not smaller than the multiplicity N, the multiplicity calculation / setting unit 64 sets the multiplicity of the multiplicity variable region to N ″.

  With the above configuration, when the multiplicity maximum value N ″ is smaller than the multiplicity N and the multiplicity may be lowered based on the availability flag, the multiplicity of the multiplicity variable region is input. As a result, the drawing time can be shortened because the number of times of drawing in the lowered multiplicity variable area is reduced, and the multiplicity maximum value N when D> A in the determination step (S108). When "" is not smaller than the multiplicity N, the multiplicity can be increased locally, and the dimensional variation due to the heating effect can be suppressed.

  As the shot data generation step (S116), the drawing data processing unit 66 reads the chip data from the storage device 140, performs a plurality of stages of conversion processing, creates shot data for each stripe area, and stores the shot data in the storage device 144. . The shot data is generated along the multiplicity set variably for each multiplicity variable region. That is, if the multiplicity variable region is a stripe region, the stripe layer has multiple layers. If the multiplicity variable region is an SF region, the SF layer is multi-layered. If the multiplicity variable area is a shot area, the shot layer has multiple layers.

  Then, as the drawing step (S118), the control circuit 120 reads the shot data configured with the set multiplicity from the storage device 144, controls the drawing unit 150, and is set using the electron beam 200. A pattern in each multiplicity variable region is drawn with multiplicity. Specifically, the drawing unit 150 operates as follows.

  The electron beam 200 emitted from the electron gun 201 (emission unit) illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole, by the illumination lens 202. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first aperture 203 is projected onto the second aperture 206 by the projection lens 204. The deflector 205 controls the deflection of the first aperture image on the second aperture 206 so that the beam shape and size can be changed. The electron beam 200 of the second aperture image that has passed through the second aperture 206 is focused by the objective lens 207, deflected by the main deflector 208 and the sub deflector 209, and continuously moved. The desired position of the sample 101 arranged in the above is irradiated. FIG. 1 shows a case in which multi-stage deflection of main and sub two stages is used for position deflection. In such a case, the electron beam 200 is deflected while following the stage movement to the reference position of the subfield (SF) which is a small area obtained by virtually dividing the stripe area by the main deflector 208, and the sub-deflector 209 deflects the electron beam 200 in the SF. What is necessary is just to deflect the beam concerning each irradiation position.

  As described above, according to the present embodiment, it is possible to reduce the drawing time even when multiple chips are drawn.

  Here, in the above-described example, the multiplicity is calculated after the drawing process is started, but the present invention is not limited to this. In actual drawing data processing, when calculating the dose density, for example, calculation is performed in units of fine mesh regions for proximity effect correction. That is, since a mesh having a size of, for example, about 1/10 of the influence range of the proximity effect is used for the proximity effect calculation, it takes time to calculate the dose density with the proximity effect corrected. Therefore, the dose density may be calculated in advance with a coarser mesh size before the drawing process is started, and the multiplicity may be set from the dose map using the dose density. Then, the number of stripe layers and the number of SF layers having a set multiplicity may be adjusted in advance. Or you may combine both. By combining them, a low-precision multiplicity can be obtained in advance before starting the drawing process, and the multiplicity can be reset only in the area that needs to be changed after the drawing process is started. As a result, multiplicity can be set with high accuracy.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In the above-described example, the multiplicity is calculated by comparing the dose obtained by multiplying the dose density by the dose area and the dose threshold A, but the present invention is not limited to this. For example, the multiplicity may be calculated by comparing the dose density with the dose density threshold. Alternatively, the multiplicity may be calculated by comparing the pattern area density with the pattern area density threshold.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all charged particle beam writing apparatuses and methods that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

10 Chip region 12 Determination region 20, 22 Stripe region 30, 32 SF region 40, 41, 42 Graphic pattern 50 Division unit 52 Pattern density calculation unit 54 Irradiation density calculation unit 56 Irradiation amount calculation unit 58 Determination unit 60 Multiplicity setting unit 62 Multiplicity Calculation Unit 64 Multiplicity Calculation / Setting Unit 66 Drawing Data Processing Unit 100 Drawing Device 101, 340 Sample 102 Electron Tube 103 Drawing Room 105 XY Stage 110 Control Computer Unit 111 Memory 120 Control Circuits 140, 142, 144 Storage Device 150 Drawing unit 160 Control unit 200 Electron beam 201 Electron gun 202 Illumination lenses 203 and 410 First aperture 204 Projection lens 205 Deflector 206 and 420 Second aperture 207 Objective lens 208 Main deflector 209 Sub deflector 330 Electron beam 411 Opening 421 variable molding Mouth 430 charged particle source

Claims (5)

A dividing unit that virtually divides a chip area to be patterned into a plurality of small areas;
A multiplicity for drawing a pattern in the small area is set for each small area so that a different multiplicity is set for at least a part of the plurality of small areas obtained by virtually dividing the chip area. A setting section to be set;
For each small region, using a charged particle beam, a drawing unit for drawing a pattern in the small region with a set multiplicity;
A charged particle beam drawing apparatus comprising: A dose map calculation unit for calculating a dose map in which the dose is defined;
2. The charged particle beam drawing according to claim 1, wherein the setting unit sets a multiplicity for drawing a pattern in the small region using each dose defined in the dose map. apparatus. A determination unit for determining whether each dose defined in the dose map is greater than a threshold;
The charged particle beam drawing apparatus according to claim 2, wherein the setting unit sets the multiplicity so that an irradiation amount per drawing does not become larger than the threshold value.   As the plurality of small regions in which the multiplicity is set, a plurality of shot regions irradiated with a charged particle beam, a plurality of subfield regions composed of at least one shot region, and one is a plurality of subfields The charged particle beam drawing apparatus according to claim 1, wherein at least one of a plurality of stripe regions constituted by regions is used. Virtually dividing the pattern formed chip region into a plurality of small regions;
A multiplicity for drawing a pattern in the small area is set for each small area so that a different multiplicity is set for at least a part of the plurality of small areas obtained by virtually dividing the chip area. A setting process;
Drawing a pattern in the small region with a set multiplicity using a charged particle beam for each small region;
A charged particle beam drawing method comprising:

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