JP2008182073A - Charged particle beam lithography device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithography device for accelerating an efficiency of the lithography process. <P>SOLUTION: The lithography device 100 includes an electron gun 201 for emitting an electron beam 200, an XY-stage 105 for mounting a sample 101, a deflector 208 for deflecting the beam, a shot data producing unit 110 for producing the shot data, a buffer 176 for temporarily storing the shot data, a lithography-time-distributional-data producing unit 174 for producing the lithography-time-distributional-data on the basis of the shot data after the shot data of the predetermined area is stored in the buffer 176, a stage-speed calculating unit 120 for calculating a traveling speed distribution of the stage on the basis of the lithography-time-distributional-data, and a deflector controlling unit 130 for controlling the deflector 208 so that the pattern included in the shot data is drawn by inputting the shot data from the buffer 176 after the traveling speed distribution of the stage is calculated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charged particle beam drawing apparatus. For example, the present invention relates to an electron beam drawing apparatus that irradiates a sample with an electron beam while variably shaping the electron beam, and a drawing method of the apparatus.

  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. 16 is a conceptual diagram for explaining the operation of a conventional variable shaping type electron beam drawing apparatus.
The variable shaping electron beam drawing apparatus (EB (Electron beam) drawing apparatus) operates as follows. In the first aperture 410, a rectangular opening 411 for forming the electron beam 432 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 432 that has passed through the opening 411 into a desired rectangular shape. The electron beam 432 irradiated from the charged particle source 430 and passed through the opening 411 is deflected by a deflector. Then, it passes through a part of the variable shaping opening 421 and irradiates the sample 440 mounted on the stage. The stage continuously moves in a predetermined direction (for example, the X direction) during drawing. That is, a rectangular shape that can pass through both the opening 411 and the variable shaping opening 421 is drawn in the drawing region of the sample 440 mounted on the stage that moves continuously. A method of creating an arbitrary shape by passing both the opening 411 and the variable forming opening 421 is referred to as a variable forming method.

  Here, for example, when drawing the sample 440 mounted on a stage that continuously moves in the X direction, it is necessary to determine the moving speed of the stage before drawing at the latest. Conventionally, first, in advance, dummy drawing is executed in which only the system program is executed without actually drawing. Then, the moving speed of the stage is determined based on the result of the dummy drawing. After the stage moving speed is determined, the system setting is switched from the dummy drawing to the actual drawing module. As a result, the actual drawing process can be started. In an actual drawing process, shot data for a drawing stripe serving as a drawing unit area is generated from the drawing data. Thereafter, the drawing stripe region is drawn according to the shot data while moving the stage at the obtained stage speed. However, with this conventional method, it is necessary to perform dummy drawing in advance separately from the drawing process.

Here, although not directly related to the moving speed of the stage, as a technique related to dummy drawing, a technique of a method for checking an arithmetic processing function in electron beam drawing is disclosed in the literature (for example, refer to Patent Document 1). .
Japanese Patent Laid-Open No. 10-242027

  As described above, a stage speed calculation time that cannot be processed in parallel with the drawing process is required separately. Therefore, the throughput of the drawing time has been reduced. Therefore, we examined various places to execute the stage speed calculation and the drawing process in parallel. Hereinafter, although not publicly known, a configuration conceived in the process until the present invention is conceived will be described.

FIG. 17 is a conceptual diagram showing the configuration of the drawing apparatus.
In the drawing apparatus 300 in FIG. 17, the drawing area of the sample 311 is virtually divided into strip-like stripe areas for drawing. In the following description, a stripe area when actually drawing is called a drawing stripe. In addition, a stripe area that is virtually divided in order to calculate the stage speed is called a speed optimized stripe. First, the shot data generation unit 310 virtually divides the drawing area into speed optimized stripes. Then, the data of the area virtually divided into speed optimized stripes is processed in advance. Then, first, shot data of the speed optimized stripe is generated. Then, drawing time distribution data is generated from the shot data of the speed optimized stripe. Then, the drawing time distribution data is sent to and stored in the stage speed calculation unit 320. After the shot data generation unit 310 completes the speed optimization stripe processing within the range necessary for calculating the stage speed of the drawing stripe, the stage speed calculation unit 320 obtains the drawing time distribution data of the same area as the drawing stripe. Extract. Then, the stage speed is calculated. Next, when the shot data generating unit 310 starts generating shot data of a drawing stripe, the shot data starts to be sent to the deflection control unit 330. When the stage controller 340 is instructed to start moving the stage, the XY stage 305 starts to move, and drawing starts when the drawing range reaches the beam deflection region. That is, the electron beam 302 is irradiated from the electron gun 301. Then, the deflection signal controlled by the deflection control unit 330 is amplified by the amplifier 315, and the electron beam 302 is deflected to a desired position by the deflector 308. The electron beam 302 is focused by the objective lens 307 and reaches the sample 311 on the moving XY stage 305.

FIG. 18 is a diagram illustrating a configuration example of stripes when performing double drawing.
FIG. 18 shows an example of double drawing. There is one layer composed of speed optimized stripes 501, 502, 505, 508, 511. Further, there are drawn stripes 503, 506, 509, 512, 514, and 516 of layers with a shift for double drawing. Also, there is one layer of non-shifted drawing stripes 504, 507, 510, 513, 515. Each speed-optimized stripe is a region that just overlaps each drawn stripe in the non-shifted layer. When calculating the stage speed of each stripe in this layer, the corresponding shot distribution data for one stripe is used. When calculating the stage speed of the stripes 503, 506, 509, 512, 514, and 516 with a shift, the stage speed spans two speed-optimized stripes. The stage speed cannot be calculated. For example, when calculating the stage speed of the stripe 506, the processing of the speed optimization stripes 501 and 502 needs to be completed. Here, problems in this method will be described below.

FIG. 19 is a diagram illustrating the order of stripe processing when performing double drawing.
First, the shot data generation unit 310 first processes the speed optimization stripe 501. Next, the shot data generation unit 310 starts processing the speed optimization stripe 502. At the same time, generation of shot data of the drawing stripe 503 whose stage speed can be calculated is started. Then, the generated shot data of the drawing stripe 503 is output to the deflection control unit 330. On the other hand, in the stage speed calculation unit 320, the shot data generation unit 310 starts processing of the speed optimization stripe 502 and calculates the stage speed of the drawing stripe 503. Then, the stage movement is performed based on the stage speed calculated after the calculation of the stage speed of the drawing stripe 503 is completed, and at the same time, the deflection control unit 330 outputs a deflection signal and the drawing stripe 503 is drawn. Subsequently, after calculation of the stage speed of the drawing stripe 504 is completed, generation of shot data of the drawing stripe 504 is started, and stage movement is performed based on the calculated stage speed, and at the same time, output to the deflection control unit 330. The The deflection control unit 330 outputs a deflection signal, and the drawing stripe 504 is drawn. When the drawing of the drawing stripes 503 and 504 is completed and the processing of the speed optimization stripe 502 is completed in the shot data generation unit 310, the shot data generation unit 310 starts processing of the speed optimization stripe 505. At the same time, generation of shot data of the drawing stripe 506 for which the stage speed can be calculated is started. Then, the generated shot data of the drawing stripe 506 is output to the deflection control unit 330. On the other hand, in the stage speed calculation unit 320, the shot data generation unit 310 starts processing of the speed optimization stripe 505 and can calculate the stage speed of the drawing stripe 506 straddling the speed optimization stripes 501 and 502. Then, the stage speed of the drawing stripe 506 is calculated. Then, the stage movement is performed based on the stage speed calculated after the calculation of the stage speed of the drawing stripe 506 is completed, and at the same time, the deflection control unit 330 outputs a deflection signal and the drawing stripe 506 is drawn. Subsequently, the stage speed of the drawing stripe 507 that is the same as the speed optimization stripe 502 is calculated. The stage movement is performed based on the stage speed calculated after the calculation of the stage speed of the drawing stripe 507 is completed. At the same time, the deflection control unit 330 outputs a deflection signal, and the drawing stripe 507 is drawn. When the processing up to the drawing stripe 516 is completed in such a procedure, the drawing is completed. In this method, as described above, there is a dependency between the speed optimization stripe and the drawing stripe processing.

FIG. 20 is a diagram illustrating a configuration example of a stripe when a null (NULL) stripe is present when performing double drawing.
FIG. 21 is a diagram showing the order of stripe processing when a NULL stripe is present when performing double drawing.
The NULL stripe indicates a stripe area where no graphic for drawing exists. In FIG. 20, the speed optimization stripe 508 is the same as in FIGS. 18 to 19, but there is no drawing pattern in the drawing stripe 509. In this case, the processing of the drawing stripe 509 is skipped and the drawing stripe 510 is drawn forward. Will be started. However, since the next drawing stripe 512 extends over the speed optimization stripe 505 and the speed optimization stripe 508, the stage speed cannot be calculated unless the processing of the speed optimization stripe 508 is completed. Therefore, a waiting time of waiting for completion is required. Therefore, useless time occurs in the drawing process. As a result, there is a problem that the throughput of the drawing apparatus is lowered.

  Accordingly, an object of the present invention is to provide a drawing apparatus that overcomes such problems and promotes the efficiency of drawing processing.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
An irradiation unit for irradiating a charged particle beam;
A stage on which a sample is placed and moved in a predetermined direction;
A deflector for deflecting a charged particle beam;
A shot data generation unit that inputs drawing data, converts the drawing data, and generates shot data in an internal format of the apparatus;
A buffer for temporarily storing shot data;
A drawing time distribution data generation unit that generates drawing time distribution data based on the shot data stored in the buffer after shot data for a predetermined area on the drawing surface of the sample is stored in the buffer;
A stage speed calculation unit for calculating a moving speed distribution of the stage when drawing a predetermined region based on the drawing time distribution data;
After the stage moving speed distribution is calculated, shot data is input from the buffer, and the pattern included in the shot data input to a predetermined area on the stage that moves according to the stage moving speed distribution is deflected. A deflection control unit for controlling the device;
It is provided with.

  First, shot data of the drawing area is generated without virtually dividing the stage speed calculation area separately from the drawing area. Then, a stage moving speed distribution is calculated based on the shot data. If there is a NULL region (NULL stripe), the stage moving speed distribution is not calculated because there is no shot data for drawing. Therefore, it is possible to prevent the waiting time from occurring.

The drawing apparatus includes a plurality of buffers,
The shot data generation unit sequentially generates shot data for the first area,
Among the plurality of buffers, one buffer stores shot data for the nth region, and the other buffer stores shot data for the (n + 1) th region,
It is preferable that the stage speed calculation unit calculates the stage moving speed distribution in order from the area of the shot data stored in the buffer that has been previously stored.

In particular, as the shot data for the nth region, shot data for the first half of the drawing unit region of any of the plurality of drawing unit regions obtained by virtually dividing the drawing surface of the sample is used,
As the shot data for the (n + 1) th area, it is preferable to use shot data for the latter half area.

  Furthermore, it is preferable that the stage speed calculation unit corrects the last speed distributed in the stage moving speed distribution for the first half area based on the drawing time distribution data for the second half area.

  In addition, the stage speed calculation unit inputs drawing time distribution data for the first half area and provisional drawing time distribution data instead of the drawing time distribution data for the second half area, and based on both data Thus, it is preferable to calculate the moving speed distribution of the stage for the first half area.

  According to the present invention, it is possible to prevent a standby time from occurring even when a NULL area exists. As a result, the drawing time can be shortened, so that the throughput can be improved.

  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.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment.
In FIG. 1, a drawing apparatus 100 is an example of a charged particle beam drawing apparatus. The drawing apparatus 100 is also an example of a variable shaping type drawing apparatus. The drawing apparatus 100 draws a predetermined pattern on the sample 101 using the electron beam 200. Here, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The drawing unit 150 includes a drawing chamber 103 and an electron column 102. In the electron column 102, 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, and a deflector 208 are disposed. An XY stage 105 is disposed in the drawing chamber 103, and a sample 101 to be drawn is placed on the XY stage 105. The control unit 160 includes a magnetic disk device 112, a shot data generation unit 110, a stage speed calculation unit 120, a deflection control unit 130, a stage control unit 140, a transfer control unit 170, a drawing control unit 180, and a shot data generation processing control unit 190. Have. The magnetic disk device 112, shot data generation unit 110, stage speed calculation unit 120, deflection control unit 130, stage control unit 140, transfer control unit 170, drawing control unit 180, and shot data generation processing control unit 190 are not shown. They are connected to each other via a bus. In the transfer control unit 170, a control unit 172, a drawing time distribution data generation unit 174, and buffers 176 and 178 are arranged. In addition, the deflection control unit 130 is connected to the deflector 208 via the amplifier 115. Drawing data is stored in the magnetic disk device 112. This drawing data is converted into shot data in the apparatus internal format, and a pattern is drawn in accordance with the shot data.

  Here, each configuration described in “˜unit” may be implemented by hardware using an electric circuit. Or you may make it implement by the combination of the hardware and software by an electric circuit. Alternatively, a combination of such hardware and firmware may be used. When software or firmware is used, a CPU serving as a control computer is arranged in the corresponding configuration. In addition, a storage device such as a memory for storing input / output data such as results calculated by the CPU is arranged. In FIG. 1, constituent parts necessary for explaining the first embodiment are described. The drawing apparatus 100 may normally include other necessary configurations.

  Next, the flow of data processing will be described. Here, in the control unit 160 of FIG. 1, the flow of data is indicated by a solid line, and the flow of control signals is indicated by a dotted line. The shot data generation processing control unit 190 sends a shot generation start instruction to the shot data generation unit 110. Then, the shot data generation unit 110 inputs as much drawing data as necessary to draw a certain drawing stripe from the magnetic disk device 112. Here, the drawing data is composed of a plurality of files. Therefore, a necessary file may be input. In drawing, the drawing area of the sample 101 is virtually divided into a plurality of strip-like drawing stripes. The drawing stripe is a drawing unit area. A drawing process is performed for each drawing stripe. When drawing data is input, the shot data generation unit 110 starts generating shot data, and the generated shot data is temporarily stored in the buffer 176 or the buffer 178 in the transfer control unit 170. At that time, the shot data generation unit 110 sequentially generates shot data for the first region. One buffer stores shot data for the nth area, and another buffer stores shot data for the (n + 1) th area. The shot data in the apparatus internal format is generated by converting the drawing data by the shot data generation unit 110. In the transfer control unit 170, the drawing time distribution data generation unit 174 generates drawing time distribution data from the generated shot data. The generated drawing time distribution data is temporarily stored in the buffer 176 or the buffer 178 together with the shot data. Each time the generation of the shot data of the drawing stripe is completed, the shot data generation unit 110 sends a stripe data generation completion notification to the shot data generation processing control unit 190.

  The shot data generation processing control unit 190 sends a stripe data generation completion notification to the drawing control unit 180 if drawing can be started. After receiving the stripe data generation completion notification, the drawing control unit 180 sends a stage speed calculation instruction to the stage speed calculation unit 120.

  Then, the stage speed calculation unit 120 reads the drawing time distribution data generated from the buffer 176 or the buffer 178 in the transfer control unit 170, and calculates the stage speed distribution (profile) of the drawing stripe. Then, the stage speed calculation unit 120 sets the stage speed distribution in the stage control unit 140 and sends a speed profile setting completion notification to the drawing control unit 180. The stage speed calculation unit 120 calculates the moving speed distribution of the stage in order from the shot data area stored in the buffer that has been previously stored.

  Next, the drawing control unit 180 sends a shot start instruction to the deflection control unit 130 and sends a stage movement start instruction to the stage control unit 140. When a shot start instruction is transmitted to the deflection control unit 130, shot data is read from the transfer control unit 170. In this way, shot data is transferred to the deflection control unit 130. On the other hand, the movement of the XY stage 105 is started by the stage control unit 140. Then, after entering the area that can be deflected by the deflector 208, drawing of the corresponding drawing stripe is started.

  On the other hand, the drawing unit 150 operates as follows. The electron beam 200 is emitted from the electron gun 201. Then, the electron beam 200 emitted from the electron gun 201 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 position of the first aperture image on the second aperture 206 is controlled by the deflector 205. As a result, the beam shape and dimensions 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. The electron beam 200 is output from the deflection control unit 130 and deflected by the deflector 208 controlled by the signal amplified by the amplifier 115. Then, the deflected electron beam 200 is applied to the sample 101 on the moving XY stage 105.

  When the deflection control unit 130 detects the stripe end of the drawing stripe that becomes the drawing unit region, the deflection control unit 130 sends a stripe end detection notification to the drawing control unit 180. Further, when the control unit 172 in the transfer control unit 170 completes the transfer of the shot data of the stripe being drawn to the deflection control unit 130, the shot data generation unit 110 is notified that the drawing of the buffer 176 or the buffer 178 has been completed. Notify by data transfer completion notification. By this notification, the shot data generation unit 110 can know the state of the buffer in the transfer control unit 170.

  As described above, the shot data generation unit 110 processes the data in the drawing stripe in advance, and generates shot data. The generated shot data is output to the transfer controller 170 and stored in the buffer. When the generation of the shot data of the drawing stripe is completed, the transfer control unit 170 creates drawing time distribution data and sends it to the stage speed calculation unit 120. The stage speed calculation unit 120 calculates the stage speed from the drawing time distribution data sent from the transfer control unit 170. On the other hand, the shot data of the drawing stripe starts to be sent from the transfer control unit 170 to the deflection control unit 130. When the stage controller 140 is instructed to start moving the stage, the XY stage 105 starts to move, and drawing starts when the drawing range reaches the beam deflection region.

FIG. 2 is a diagram illustrating a configuration example of stripes when performing double drawing in the first embodiment.
FIG. 2 shows an example of double drawing. There are one drawing stripe 1, 3, 5, 7, 9, 11 with a shifted layer for double drawing, and two drawing stripes 2, 4, 6, 8, 10 with no shifting. The speed-optimized stripe described with reference to FIG. 18 and the like disappears, and the distribution data of the drawing time necessary for calculating the stage speed is created from the result of generating the shot data of the drawing stripe. The drawing time distribution can be generated as follows, for example. First, the drawing stripe is divided with a predetermined width in the x direction, for example. A plurality of compartments (CPM) 70 are assumed. Then, the drawing time that is the sum of the shot time of the shot to be drawn in each CPM 70 and the settling time of the amplifier 115 at each shot is calculated. As the shot time, the beam irradiation time included in the shot data may be used. Further, the settling time can be calculated by obtaining the amount of change in the deflection distance from the coordinates of the shot data. In this way, the drawing time distribution data (CPM data) can be generated by calculating the drawing time for each CPM 70 divided at a predetermined interval.

FIG. 3 is a diagram showing the order of stripe processing when double drawing is performed in the stripe configuration of FIG.
The shot data generation unit 110 generates a shot of the drawing stripe 1 and stores it in the buffer 176. When the generation is completed, the shot generation of the next drawing stripe 2 is started, and the drawing time distribution data generation unit 174 generates the drawing time distribution data of the drawing stripe 1. When the stage speed calculation unit 120 calculates the stage speed of the drawing stripe 1, drawing of the drawing stripe 1 is started. In this way, when the processing up to the drawing stripe 11 is completed, the drawing is completed. In the first embodiment, drawing stripe shot generation is always preceded, the stage speed is calculated after generation is completed, and stripe drawing is performed. Here, the stage speed can be calculated by dividing the drawing time for each CPM 70 by the width of the CPM 70. Also, if the difference V between the front and rear stage speeds is too large, the XY stage 105 may not be able to follow when shifting from the previous speed to the subsequent speed. Therefore, in calculating the stage speed, it is preferable to calculate the speed so that the XY stage 105 is distributed at a speed that can be followed. For example, the maximum value of the speed difference V may be set in advance, and the fast side speed may be reached so as to be within the range.

FIG. 4 is a diagram showing a configuration example of a stripe when a NULL stripe is present when performing double drawing in the first embodiment.
FIG. 5 is a diagram showing the order of stripe processing when double drawing is performed in the stripe configuration of FIG.
The drawing stripe 4 is the same as in FIG. 2, but the drawing stripe 5 has no drawing pattern. In this case, the processing of the drawing stripe 5 is skipped (omitted) and the processing of the drawing stripe 6 is started ahead of schedule. Therefore, no waiting time occurs. In this way, everything from shot generation to drawing is advanced, and the entire drawing time is shortened.

  In addition, the configuration of the first embodiment achieves the following effects in addition to the effect that drawing does not stop even when NULL data as described above is generated. When multiple drawing is performed with a configuration using speed optimized stripes, subfield shifting is performed in addition to stripe shifting for multiple drawing. As a result, variations in beam position caused by random noise or beam deflection position errors can be reduced. The subfield (SF) is a small area obtained by further dividing the stripe. SF becomes a sub deflection region when the multistage deflector is used. As a result of shifting the subfield, the grid of the subfield changes. Therefore, it may affect the affiliation of subfields at the stripe boundary. As a result, an error occurs in the drawing time distribution. For example, in double drawing, one layer is the same as the optimized stripe, but the grid of the subfield is changed in the other layer. Then, in order to obtain the speed distribution for two layers with the speed optimized stripe for one drawing layer, such an error factor occurs. On the other hand, in Embodiment 1, since the distribution of the drawing time is obtained from the shot data itself of the drawing stripe that is actually used, such an error does not occur.

FIG. 6 is a diagram illustrating an example of how to use the buffer in the first embodiment.
One buffer stores shot data that is being generated, and the other buffer stores shot data that has been generated. In FIG. 6A, shot data being generated is sequentially stored in the buffer 176, and shot data that has already been generated is stored in the buffer 178. Then, the drawing time distribution data (CPM data) extracted from the shot data is sent to the stage speed calculation unit 120 from the buffer 178 that has already been generated, and the stage speed calculation unit 120 generates a profile of the stage speed. Then, stage speed profile data is set in the stage controller 140. Thereafter, when the drawing conditions of the stage control unit 140 and the deflection control unit 130 are satisfied, stage movement is started based on the set stage speed profile, and the deflection control unit 130 reads shot data from the buffer 178 and starts stripe drawing. Is done. Then, when the drawing for the data stored in the buffer 178 is completed, the shot data of the next drawing area is now stored in the buffer 176 as shown in FIG. 6B. On the other hand, the shot data during the generation of new shots is sequentially stored in the buffer 178. Then, the drawing time distribution data (CPM data) extracted from the shot data from the buffer 176 that has already been generated is sent to the stage speed calculator 120, and the stage speed calculator 120 generates a profile of the stage speed. Then, stage speed profile data is set in the stage controller 140. Thereafter, when the drawing conditions of the stage control unit 140 and the deflection control unit 130 are established, the stage movement is started based on the set stage speed profile, and the deflection control unit 130 reads the shot data from the buffer 176 and starts the stripe drawing. Is done.

FIG. 7 is a diagram illustrating an example of how the buffer is used in the transfer control unit when data for one stripe fits in the buffer according to the first embodiment.
FIG. 7A shows the state of the preceding process for generating the first shot data. While the shot data of the stripe 1 being generated is being stored in the buffer 176, drawing cannot be started yet. In FIG. 7B, the shot data storage of the first stripe 1 is completed in the buffer 176, and drawing is started. In the buffer 178, accumulation of shot data of the next stripe 2 has started. In FIG. 7C, drawing of the stripe 1 is completed and drawing of the stripe 2 is started. Further, the generation of shot data for the stripe 3 is started and the shot data is accumulated in the buffer 176. In the example of FIG. 7, one stripe of data is stored in one buffer, but a plurality of stripe data may be stored in one buffer.

FIG. 8 is a diagram illustrating an example of how the buffer is used in the transfer control unit when data for one stripe does not fit in the buffer according to the first embodiment.
FIG. 8A shows the state of the preceding process for generating the first shot data. Drawing data for the first half of the stripe 1 being generated is being stored in the buffer 176, and drawing cannot be started yet. In FIG. 8B, storage of shot data of the first half of the first stripe 1 is completed in the buffer 176, and drawing is started. In the buffer 178, accumulation of shot data of the second half of the stripe 1 has started. In FIG. 8C, drawing of the first half of the stripe 1 is completed, and drawing of the second half of the stripe 1 is started. Further, the generation of the shot data of the stripe 2 is started and the shot data is accumulated in the buffer 176. In the example of FIG. 8, one stripe is divided into two, but even if more divisions are performed, the same processing can be used.

FIG. 9 is a diagram illustrating an example of re-evaluation of the speed profile in the stage speed calculation unit when data for one stripe does not fit in the buffer according to the first embodiment.
FIG. 9A shows a speed profile 30 generated by extracting the CPM data 20 from the shot data of the first half of the stripe stored in the first buffer 176. FIG. 9B shows a speed profile 32 generated by extracting the CPM data 22 from the shot data of the latter half of the stripe stored in the other buffer 178. FIG. 9C shows a case where the speed profile 30 and the speed profile 32 described above are generated separately and simply connected. When the separately generated profiles are simply connected in this way, the speed difference V increases at the boundary between the speed profiles of the first half and the second half. Therefore, there is a possibility that the speed profile may not be followed by the XY stage 105 in practice.

  Therefore, as shown in FIG. 9D, the stage speed calculator 120 creates a speed profile 30 in the first half of the stripe, and when the generation of shot data in the second half is completed, The speed profile 31 is regenerated using the CPM data 24 combined with the latter half. In that case, the last speed of the first half is corrected to a speed that can be followed so that the XY stage 105 can follow. FIG. 9D shows a case where tracking is possible by decelerating by the speed V1. Then, the stage speed calculation unit 120 sends an instruction to change the speed profile 30 to the speed profile 31 to the stage control unit 140. Upon receiving such a speed profile change instruction, the stage control unit 140 switches the speed profile and continues drawing without stopping the XY stage 105 during drawing movement. By configuring as described above, it is possible to prevent drawing stoppage due to the inability to follow the XY stage 105.

FIG. 10 is a diagram for explaining speed profile switching processing in the case where the generation of shot data in the latter half of the first embodiment is in time.
First, the speed profile 30 of the first half of the stripe is set in the stage controller 140 from the stage speed calculator 120. When a stripe drawing start instruction is received, the stage must be moved according to the speed profile 30 in the first half. When the second half shot generation is completed while the first half stripe drawing movement is performed, the stage speed calculation unit 120 generates a speed profile 31 that combines the first half part and the second half part, and sets the speed profile 31 in the stage control unit 140. . If the speed profile has been updated, the stage is switched to the new speed profile 31 and the stage movement is continued. As described above, if switching is performed before shifting to the final speed of the first half, stage movement is performed continuously even in drawing of a stripe divided into a plurality of buffers, and the drawing operation is temporarily performed by switching the buffer. No disruption occurs. However, there is a case where the generation of the short-term shot data is not in time.

FIG. 11 is a diagram for explaining speed profile addition processing when the generation of the short-term shot data in the first embodiment is not in time.
As shown in FIG. 11, when it takes time to generate the second half of the shot data and the drawing operation of the first half is completed and the XY stage 105 is stopped, the process restarts from the stopped state. In this case, the stage speed calculation unit 120 generates the original second half speed profile 32. And the stage control part 140 should just continue drawing from a stop position. At that time, it is preferable that the XY stage 105 starts to move from a position returned before the stop position by the distance for acceleration.

  As described above, the case where the generation of the short-term shot data is in time can be dealt with, and the case where the short-time shot data is not in time can be dealt with. The speed profile may be switched by the stage controller 140 automatically selecting and switching. This selection may be made, for example, based on whether the stage control unit 140 has received a speed profile change instruction before shifting to the final speed of the first half. By configuring as described above, even if the processing capability is reduced for some reason, it takes time to generate shots, the stage movement of the first half of the stripe is completed before setting the speed profile, and the XY stage 105 stops, The XY stage 105 can be restarted to perform a drawing operation.

Embodiment 2. FIG.
As described in the first embodiment, shot data of one drawing stripe may be divided into a plurality of buffers. At that time, it may be necessary to create a stage speed profile and start drawing at a stage where all the distribution data of the stripe are not available. In this case, if the speed profile is created only with the drawing time distribution data of the first half, the drawing time distribution of the second half is not taken into consideration, so the speed profile is different from that created when the drawing time distribution data of the second half is collected. There is a case. In that case, there is a possibility that the range of influence may also be exerted on the speed profile of the part that has already started drawing. If the stage position has already reached the influence range and there is a large speed difference with the speed profile created later, it becomes impossible to follow the boundary between the first half and the second half, and a recovery operation such as a restart occurs. there's a possibility that. Therefore, it is desirable to reduce the influence of the latter half. Therefore, in the second embodiment, a drawing time evaluation unit before drawing is provided, and a velocity profile is created by supplementing the drawing time distribution data of the insufficient portion. Thereby, the influence when the speed profile of the rear part is created is reduced.

FIG. 12 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the second embodiment.
In FIG. 12, the control unit 160 further includes a pre-drawing drawing time evaluation unit 122 in addition to the configuration shown in FIG. The other points are the same as in FIG. Then, the drawing time evaluation unit 122 before drawing reads the drawing data from the magnetic disk device 112. The drawing time evaluation unit 122 before drawing creates simple drawing time distribution data of all drawing stripes prior to drawing. For example, in the simple drawing time distribution data, drawing data is divided into sizes corresponding to stripes, each stripe region is further divided into CPM regions, and a figure included in each CPM region is divided into shot data sizes. If the number of shots is estimated, the approximate drawing time of each CPM region can be estimated from the irradiation time per shot. The simple drawing time distribution data is provisional drawing time distribution data. The drawing time distribution data created immediately before the drawing by the transfer control unit 170 is calculated with the shot time, the settling time, etc. being distributed and calculated for each CPM region divided in advance, so that the accuracy is very high. However, when shot data for one drawing stripe extends over a plurality of buffers, not all drawing time distribution data for one stripe is prepared at the start of drawing. On the other hand, since the simple drawing time distribution data calculated in advance by the drawing time evaluation unit 122 before drawing is simply obtained, the accuracy is slightly reduced, but the distribution data of all one stripe can be prepared.

FIG. 13 is a diagram illustrating an example of how to use the buffer according to the second embodiment.
In FIG. 13A, shot data in the other buffer 178 is drawn while storing shot data in the buffer 176 in the preceding process. At that time, the drawing time distribution data is transferred to the stage speed calculator 120 before drawing. On the other hand, provisional drawing time distribution data calculated in advance by the drawing time evaluation unit 122 before drawing is also output from the drawing time evaluation unit 122 before drawing to the stage speed calculation unit 120. When shot data for one stripe fits in one buffer, a speed profile may be created using highly accurate drawing time distribution data. However, when the drawing time distribution data for one stripe does not exist because the data is divided into a plurality of buffers, the shortage is supplemented with temporary drawing time distribution data simply obtained by the drawing time evaluation unit 122 before drawing. Here, a case where data of the first half of one stripe is stored in the buffer 178 is shown.

  Here, in the case of changing from a low speed to a high speed, even if the XY stage 105 cannot follow, it is only lower than the set speed, so that drawing does not stop. Conversely, when the XY stage 105 cannot follow when the speed changes from a high speed to a low speed, the actual speed becomes faster than the set speed, and the possibility of drawing stop increases. Therefore, it is preferable to adjust the shot time distribution data obtained simply by multiplying the safety factor in advance so that the speed is slow.

FIG. 14 shows a procedure for generating a speed profile when shot data of one stripe in the second embodiment is divided into two buffers.
In FIG. 14A, the drawing time distribution data (CPM data) obtained from the buffer 178 is only the first half CPM data 20, but the provisional drawing time distribution data (DWS data) 44 is provided for one stripe. . The provisional drawing time distribution data 44 is composed of provisional drawing time distribution data 40 in the first half and provisional drawing time distribution data 42 in the second half. If the division sizes of these distribution data are prepared in advance, as shown in FIG. 14B, the high-accuracy CPM data 20 in the first half is supplemented with temporary drawing time distribution data 42 to cover one stripe. Distribution data can be prepared. The stage speed calculation unit 120 calculates the speed profile 50 from the distribution data of this combination. In this case, since the temporary drawing time distribution data 42 is simple distribution data, an error is included in comparison with the CPM data 20 in the first half. For this reason, when the maximum error appears in a direction in which the shot time is short, the speed becomes too high, and the possibility of recovery such as drawing stop and restart is increased. Therefore, the provisional drawing time distribution data 42 may be adjusted in advance so that the speed is slowed by a safety factor. Of the speed profiles 50 thus obtained, the speed profile 51 excluding the speed of the rear end portion of the front half is set in the stage controller 140 as shown in FIG. The reason for removing the last speed is that when a speed profile is created when the CPM data 22 in the latter half is complete, there is a possibility that the boundary portion between the high-precision shot distribution and the simple shot distribution will slightly change. Therefore, it is not set here because it is set when the latter half is complete.

  When the drawing of the data stored in the buffer 178 is completed, the shot data in the buffer 176 is drawn while the next shot data is stored in the buffer 178, as shown in FIG. That is, the case where data in the latter half of one stripe is stored in the buffer 176 is shown. When the second half of the shot data accumulates in the buffer 176, the drawing time distribution data generation unit 174 creates the second half CPM data 22. At this point, drawing of the first half of the stripe has already started. At the time when the CPM data 22 is created, as shown in FIG. 14E, the drawing time distribution data for the first half and the second half are ready, so that it is possible to create a highly accurate velocity profile for one entire stripe. . However, the first half is already being drawn, and the speed profile cannot be changed. Therefore, as shown in FIG. 14F, the stage speed calculation unit 120 creates the speed profile 53 of the second half part under the constraint that the speed profile 51 already set in the stage control unit 140 is not changed. Then, as shown in FIG. 14 (g), the remaining speed profile 53 is set in the stage control unit 140.

FIG. 15 is a diagram illustrating another example of a speed profile generation procedure when one stripe of shot data according to the second embodiment is divided into two buffers.
In FIG. 15A, the CPM data 20 obtained from the buffer 178 is only the first half, but the provisional drawing time distribution data (DWS) is provided for one stripe. As described above, the temporary drawing time distribution data 44 includes the first half of the temporary drawing time distribution data 40 and the second half of the temporary drawing time distribution data 42. The stage speed calculation unit 120 extracts the drawing time 43 of the portion having the highest shot density from the temporary drawing time distribution data 42. It is assumed that the second half is all this shot density. Then, tentative drawing time distribution data 45 in the latter half part assuming that all CPMs are the drawing time 43 is assumed. Then, as shown in FIG. 15C, a speed profile 60 is created from the combination of the CPM data 20 and the temporary drawing time distribution data 45. In this case, since the temporary drawing time 43 is simple data, as described above, it is preferable to adjust the speed so as to slow down by multiplying the safety factor in advance. Then, as shown in FIG. 15 (d), a speed profile 61 from which the rear end portion is removed is set in the stage controller 140 among the speed profiles 60. In this case as well, it is desirable to set the rest when CPM data in the latter half of the high accuracy is available.

  When the second half of the shot data accumulates in the buffer 176, the drawing time distribution data generation unit 174 creates the second half CPM data 22. At this point, drawing of the first half of the stripe has already started. At the time when the CPM data 22 is created, as shown in FIG. 15E, the drawing time distribution data for the first half and the second half are ready, so that it is possible to create a highly accurate speed profile for the entire stripe. . However, the first half is already being drawn, and the speed profile cannot be changed. Therefore, as shown in FIG. 15 (f), the stage speed calculation unit 120 creates the speed profile 63 of the second half part under the constraint that the speed profile 61 already set in the stage control unit 140 is not changed. Then, as shown in FIG. 15G, the remaining speed profile 63 is set in the stage control unit 140.

  By configuring as described above, the setting speed of the first half portion is set lower. Although the stripe throughput may be reduced, the possibility of drawing stop and restart can be reduced by previously setting a lower stage speed at the boundary portion.

  Here, the drawing time evaluation unit 122 before drawing may be further simplified, and the drawing time assuming that the shot density is the highest in the system design may be generated as temporary drawing time distribution data in the latter half. Then, the first half of the speed profile may be generated by combining the provisional drawing time distribution data of the latter half. In this case, there is a possibility that the speed profile may be set slower, but it is possible to further avoid the occurrence of recovery such as drawing stop and restart of the boundary portion. It is a rare phenomenon that a stripe is divided into a plurality of buffers, and if the ratio to the entire drawing is not large, it is effective when it is desired to avoid the occurrence of recovery at the expense of some throughput.

  In the above description, the processing content or operation content described as “to part” may be configured by a computer-operable program. Alternatively, it may be configured by hardware. Or you may make it implement by not only the program used as software but the combination of hardware and software. Alternatively, a combination with firmware may be used. When configured by a program, the program is recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (Read Only Memory).

  In FIG. 1 or FIG. 12, “to part” further indicates a RAM (Random Access Memory), ROM, magnetic disk (HD) device, and input means, which are examples of a storage device, via a bus (not shown). Connected to a keyboard (K / B), a mouse, a monitor, a printer as an example of output means, an external interface (I / F) as an example of an input output means, FD, DVD, CD, etc. It doesn't matter.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  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 subfield division methods, stage speed determination methods, charged particle beam drawing apparatuses, and charged particle beam drawing 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. The

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. 6 is a diagram illustrating a configuration example of a stripe when performing double drawing in Embodiment 1. FIG. FIG. 3 is a diagram showing the order of stripe processing when performing double drawing in the stripe configuration of FIG. 2. 6 is a diagram illustrating a configuration example of a stripe when a NULL stripe is present when performing double drawing in Embodiment 1. FIG. FIG. 5 is a diagram showing the order of stripe processing when double drawing is performed in the stripe configuration of FIG. 4. 6 is a diagram illustrating an example of how to use a buffer in Embodiment 1. FIG. 6 is a diagram illustrating an example of how to use a buffer in a transfer control unit when data for one stripe fits in the buffer in Embodiment 1. FIG. 6 is a diagram illustrating an example of how to use a buffer in a transfer control unit when data for one stripe does not fit in the buffer according to Embodiment 1. FIG. 6 is a diagram illustrating an example of a reevaluation of a speed profile in a stage speed calculation unit when data for one stripe does not fit in the buffer according to Embodiment 1. FIG. FIG. 10 is a diagram for describing speed profile switching processing in a case where generation of shot data in the latter half of the first embodiment is in time. FIG. 10 is a diagram for describing speed profile addition processing when the generation of shot data in the latter half of the first embodiment is not in time. 6 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 2. FIG. 10 is a diagram illustrating an example of how to use a buffer in Embodiment 2. FIG. 10 shows a procedure for generating a speed profile when shot data of one stripe in the second embodiment is divided into two buffers. FIG. 10 is a diagram illustrating another example of a procedure for generating a speed profile when one-stripe shot data according to the second embodiment is divided into two buffers. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus. It is a conceptual diagram which shows the structure of a drawing apparatus. It is a figure which shows the structural example of the stripe in the case of performing double drawing. It is a figure which shows the order of the stripe process in the case of performing double drawing. It is a figure which shows the structural example of a stripe when a null (NULL) stripe exists when performing double drawing. It is a figure which shows the order of the stripe process when a NULL stripe exists when performing double drawing.

Explanation of symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 Drawing stripes 20, 22, 24 CPM data 30, 31, 32, 50, 51, 53, 60, 61, 63 Speed profile 40 , 42, 44, 45 Temporary drawing time distribution data 43 Drawing time 70 CPM
100, 300 Drawing apparatus 101, 311, 440 Sample 102 Electron barrel 103 Drawing chamber 105, 305 XY stage 110, 310 Shot data generation unit 112 Magnetic disk unit 115, 315 Amplifier 120, 320 Stage speed calculation unit 122 Drawing time before drawing Evaluation unit 130, 330 Deflection control unit 140, 340 Stage control unit 150 Drawing unit 160 Control unit 170 Transfer control unit 172 Control unit 174 Drawing time distribution data generation units 176, 178 Buffer 180 Drawing control unit 190 Shot data generation processing control unit 200 , 302 Electron beam 201, 301 Electron gun 202 Illumination lens 203, 410 First aperture 204 Projection lens 205, 208, 308 Deflector 206, 420 Second aperture 207, 307 Objective lens 411 Opening 421 Possible Shaped opening 430 a charged particle source 432 electron beam 501,502,505,508,511 speed optimization stripe 503,504,506,507,509,510 drawing stripe 512,513,514,515,516 drawing stripes

Claims (5)

An irradiation unit for irradiating a charged particle beam;
A stage on which a sample is placed and moved in a predetermined direction;
A deflector for deflecting the charged particle beam;
A shot data generation unit that inputs drawing data and converts the drawing data to generate shot data in an internal format of the apparatus;
A buffer for temporarily storing the shot data;
After the shot data for a predetermined area on the drawing surface of the sample is stored in the buffer, a drawing time distribution data generation unit that generates drawing time distribution data based on the shot data stored in the buffer;
A stage speed calculator that calculates a moving speed distribution of the stage when drawing the predetermined area based on the drawing time distribution data;
After the movement speed distribution of the stage is calculated, the shot data is input from the buffer, and a pattern included in the shot data input to the predetermined area on the stage that moves according to the movement speed distribution of the stage A deflection controller that controls the deflector to be drawn;
A charged particle beam drawing apparatus comprising: The drawing device includes a plurality of the buffers,
The shot data generation unit sequentially generates shot data for the first region,
Of the plurality of buffers, one buffer stores shot data for the nth region, and another buffer stores shot data for the (n + 1) th region,
2. The charged particle beam drawing apparatus according to claim 1, wherein the stage speed calculation unit calculates a moving speed distribution of the stage in order from an area of shot data stored in a buffer that has been previously stored. As the shot data for the nth region, shot data for the first half of the drawing unit region of any of the plurality of drawing unit regions obtained by virtually dividing the drawing surface of the sample is used,
3. The charged particle beam drawing apparatus according to claim 2, wherein the shot data for the second half area is used as the shot data for the (n + 1) th area.   The stage speed calculator corrects the last speed distributed in the moving speed distribution of the stage for the first half area based on the drawing time distribution data for the second half area. 3. The charged particle beam drawing apparatus according to 3.   The stage speed calculation unit inputs drawing time distribution data for the first half area and provisional drawing time distribution data instead of the drawing time distribution data for the second half area. 4. The charged particle beam drawing apparatus according to claim 3, wherein a moving speed distribution of the stage for the first half area is calculated based on the first half area.

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