JP7430094B2 - Charged particle beam lithography device and lithography method - Google Patents

Description

The present invention relates to a charged particle beam lithography apparatus and a lithography method.

A charged particle beam drawing device is a device for drawing a pattern on a drawing material using a charged particle beam. As such a charged particle beam lithography apparatus, a direct lithography type apparatus is known, which scans a material with a finely focused charged particle beam to draw an arbitrary pattern. As such a charged particle beam drawing apparatus, for example, Patent Document 1 discloses an electron beam drawing apparatus that draws a pattern on a drawing material with an electron beam.

Japanese Patent Application Publication No. 2012-15227

In an electron beam lithography system, the following relationship exists between resist sensitivity Q [C/cm ² ], beam current I [A], lithography area S [cm ² ], and lithography time T [s].

Q=IT/S

Further, the scanning speed F [Hz] of the electron beam when scanning the drawing material with the electron beam to draw a pattern is given by the following equation, when the scanning step of the electron beam is p [cm].

F=I/(Qp ² )

Therefore, in order to shorten the writing time T, it is necessary to increase the beam current I or select a resist with a small sensitivity Q. Even when increasing the beam current I or selecting a resist with a small sensitivity Q, the scanning speed F of the electron beam becomes faster. Therefore, in order to shorten the drawing time T and improve the drawing throughput, it is required to increase the scanning speed F, that is, to increase the scanning frequency.

As a clock output circuit that outputs a clock signal that determines the scanning speed, for example, a clock output circuit using a PLL (Phase Locked Loop) circuit is used. A clock output circuit using a PLL circuit can obtain a clock signal with an extremely high frequency compared to, for example, a clock output circuit using a ring oscillator.

Here, in the electron beam lithography apparatus, the scanning speed of the electron beam is not constant. For example, the scanning speed is changed when correcting a change in the dose amount due to a change in the beam current during writing, or when the required dose amount is different for each pattern to be written.

However, in a clock output circuit using a PLL circuit, it takes time to switch the frequency of a clock signal. Therefore, the drawing throughput decreases.

One aspect of the charged particle beam lithography apparatus according to the present invention is
A charged particle beam drawing device that draws a pattern on a drawing material with a charged particle beam,
a charged particle beam source that generates the charged particle beam;
a deflector that deflects the charged particle beam;
a scan frequency calculation unit that calculates the scan frequency;
a clock signal output section that switches the frequency of the clock signal according to the scan frequency;
a deflector control unit that causes the deflector to deflect the charged particle beam based on the clock signal;
a storage unit storing pattern data of the pattern made up of a plurality of partial patterns and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
a pattern data generation unit that generates a plurality of partial pattern data by extracting the partial patterns having the same shot time condition from the pattern data;
a sorting processing unit that arranges the plurality of partial patterns for each of the partial pattern data to generate a partial pattern sequence;
including;
performing a process of drawing the partial patterns in the order in which they are arranged in the partial pattern column;
The process of drawing the partial pattern is as follows:
a process in which the scan frequency calculation unit calculates the scan frequency based on the shot time condition;
a process in which the deflector control unit causes the deflector to draw the partial pattern at the scan frequency determined by the scan frequency calculation unit ;
including .

In such a charged particle beam drawing apparatus, partial patterns drawn at the same scan frequency are drawn continuously, so the number of times the scan frequency is switched can be reduced, and the drawing throughput can be improved.

One aspect of the drawing method according to the present invention is
A drawing method for drawing a pattern on a drawing material using a charged particle beam,
acquiring pattern data of the pattern made up of a plurality of partial patterns, and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
generating a plurality of partial pattern data by extracting the partial patterns having the same shot time condition from the pattern data;
arranging the plurality of partial patterns according to the partial pattern data to generate a partial pattern sequence;
drawing the partial patterns in the order arranged in the partial pattern row;
including;
The step of drawing the partial pattern includes:
determining a scan frequency when drawing the partial pattern based on the shot time condition;
causing a deflector that deflects the charged particle beam to draw the partial pattern at the scanning frequency;
including.
One aspect of the drawing method according to the present invention is
A drawing method for drawing a pattern on a drawing material using a charged particle beam,
acquiring pattern data of the pattern made up of a plurality of partial patterns, and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
in each of the plurality of partial patterns, determining a scan frequency when drawing the partial pattern based on the shot time condition;
A partial pattern in which the scan frequency is equal to or less than a threshold is extracted from the pattern data to generate partial pattern data, a partial pattern in which the scan frequency is greater than the threshold is extracted from the pattern data, and the partial pattern is extracted from the extracted partial pattern. generating a plurality of partial pattern data by extracting partial patterns having the same shot time condition;
A plurality of partial patterns are arranged for each partial pattern data to form a partial pattern string.
The process of generating;
drawing the partial patterns in the order arranged in the partial pattern row;
including;
The step of drawing the partial pattern includes:
determining a scan frequency when drawing the partial pattern based on the shot time condition;
causing a deflector that deflects the charged particle beam to draw the partial pattern at the scanning frequency;
including;
In the step of causing the deflector to draw the partial pattern, the charged particle beam is deflected by the deflector based on the clock signal output from a clock signal output unit that switches the frequency of a clock signal according to the scan frequency. let me,
The clock signal output section includes:
a first clock generation circuit;
a second clock generation circuit;
a selector that selects a clock signal generated by the first clock generation circuit or a clock signal generated by the second clock generation circuit;
has
The frequency of the clock signal generated by the second clock generation circuit is higher than the frequency of the clock signal generated by the first clock generation circuit,
A switching time for switching the frequency of the clock signal of the second clock generation circuit is longer than a switching time for switching the frequency of the clock signal of the first clock generation circuit,
In the step of drawing the partial pattern on the deflector,
If the scan frequency is less than or equal to the threshold, the selector selects the clock signal generated by the first clock generation circuit, and if the scan frequency is greater than the threshold, the selector selects the clock signal generated by the second clock generation circuit. Select the generated clock signal.

In such a drawing method, partial patterns drawn at the same scan frequency are drawn continuously, so the number of times the scan frequency is switched can be reduced, and the drawing throughput can be improved.

FIG. 1 is a diagram showing the configuration of an electron beam lithography apparatus according to an embodiment. FIG. 3 is a diagram for explaining pattern data of a pattern drawn on a drawing material. FIG. 1 is a diagram showing the configuration of a clock signal output section of an electron beam lithography apparatus according to an embodiment. 1 is a flowchart illustrating an example of the operation of the electron beam lithography apparatus according to the embodiment. FIG. 3 is a diagram for explaining processing of a pattern data generation unit. FIG. 3 is a diagram for explaining processing of a sort processing unit. The figure which shows an example of the method of drawing a pattern. FIG. 3 is a diagram for explaining an example of a partial pattern sequence. FIG. 7 is a diagram showing a configuration of a clock signal output section of an electron beam lithography apparatus according to a first modification. 12 is a flowchart showing an example of the operation of the electron beam lithography apparatus according to the second modification. FIG. 7 is a diagram for explaining processing of a pattern data generation unit of an electron beam lithography apparatus according to a second modification.

Hereinafter, preferred embodiments of the present invention will be described in detail using the drawings. Note that the embodiments described below do not unduly limit the content of the present invention described in the claims. Furthermore, not all of the configurations described below are essential components of the present invention.

The charged particle beam lithography apparatus according to the present invention will be described below using an example of an electron beam lithography apparatus that draws a pattern on a lithography material with an electron beam. ) may be used to draw a pattern.

1. Electron beam lithography apparatus First, an electron beam lithography apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of an electron beam lithography apparatus 100 according to this embodiment.

The electron beam drawing device 100 is a device that draws a pattern on the drawing material M by scanning the drawing material M with a finely focused electron beam. The electron beam drawing apparatus 100 is used, for example, to manufacture a photomask such as a reticle. The drawing material M is, for example, a mask blank in which a metal film such as a chromium film is formed on a quartz substrate, and a resist is applied thereto. In the electron beam drawing apparatus 100, the resist of the drawing material M is exposed to an electron beam.

As shown in FIG. 1, the electron beam drawing apparatus 100 includes an electron source 10 (an example of a charged particle beam source), an accelerating electrode 11, a blanking aperture 12, a blanker 13, an electrostatic lens 14, and a condenser lens. 15a, a condenser lens 15b, an objective diaphragm 16, an objective lens 17, an astigmatism corrector 18, a deflector 19, a stage 20, a height measuring device 21, and a Faraday cup 22.

Further, the electron beam lithography apparatus 100 includes a high voltage control section 30, a blanking control section 31, a lens control section 32, a scan frequency calculation section 33, a clock signal output section 34, and a sub-deflector control section 35. , a main deflector control section 36, a height measurement control section 37, an ammeter 38, and a stage control device 39.

Further, the electron beam lithography apparatus 100 includes a lithography control section 40 and an information processing apparatus 50.

Electron source 10 generates an electron beam. The accelerating electrode 11 accelerates the electron beam generated by the electron source 10.

The blanking aperture 12 is an aperture for blocking electron beams. Blanker 13 deflects the electron beam onto blanking aperture 12 . Electrostatic lens 14 focuses the electron beam onto blanking aperture 12 .

For example, when the drawing material M is not irradiated with the electron beam, the electron beam is deflected by the blanker 13 and shielded by the blanking aperture 12. Further, when the drawing material M is irradiated with the electron beam, the electron beam is not deflected by the blanker 13, but is allowed to pass through the aperture hole of the blanking aperture 12. In this way, the electron beam can be turned on and off by operating the blanker 13.

Condenser lens 15a and condenser lens 15b converge the electron beam. The objective aperture 16 controls the aperture angle of the electron beam. The objective lens 17 focuses the electron beam onto the drawing material M. The astigmatism corrector 18 corrects astigmatism of the objective lens 17.

Deflector 19 deflects the electron beam. The deflector 19 includes a sub-deflector 19a and a main deflector 19b.

The main deflection area where the main deflector 19b can deflect the electron beam is larger than the sub deflection area where the sub deflector 19a can deflect the electron beam. The sub-deflector 19a deflects the electron beam faster than the main deflector 19b. The main deflector 19b is used, for example, to change the position of the sub-deflection area. The sub-deflector 19a is used, for example, to scan the electron beam within the sub-deflection region.

The stage 20 holds the drawing material M. The stage 20 can move the drawing material M. The height measuring device 21 measures the height of the drawing material M. Faraday cup 22 measures beam current. The beam current is the amount of current of the electron beam with which the drawing material M is irradiated.

In the electron beam drawing apparatus 100, an electron beam emitted from the electron source 10 is focused by a condenser lens 15a, a condenser lens 15b, and an objective lens 17, and is irradiated onto a drawing material M. The electron beam is switched on and off by a blanker 13. Further, the electron beam is irradiated onto a desired position by a deflector 19. By moving the drawing material M on the stage 20, drawing can be performed in a wider range than the main deflection area. In the electron beam drawing apparatus 100, before drawing, the height of the surface of the drawing material M is measured using the height measuring device 21, and the beam current is measured using the Faraday cup 22.

The high voltage control section 30 applies an accelerating voltage to the accelerating electrode 11 . Further, the high voltage control section 30 controls the electrostatic lens 14. The blanking control section 31 controls the blanker 13. The lens control unit 32 controls the condenser lens 15a, the condenser lens 15b, the objective lens 17, and the astigmatism corrector 18.

The scan frequency calculation unit 33 calculates the scan frequency based on the drawing conditions. The scan frequency corresponds to the scanning speed of the electron beam.

The clock signal output section 34 outputs a clock signal. The clock signal is a timing clock for scanning the electron beam. The clock signal output section 34 switches the frequency of the clock signal according to the scan frequency determined by the scan frequency calculation section 33. The clock signal output from the clock signal output section 34 is sent to the sub-deflector control section 35.

The sub-deflector control section 35 controls the sub-deflector 19a. The sub-deflector control unit 35 operates the sub-deflector 19a based on the clock signal. Thereby, the electron beam can be scanned at the scan frequency determined by the scan frequency calculation section 33. Further, the sub-deflector control unit 35 receives pattern information from the information processing device 50 and controls the sub-deflector 19a based on the pattern information. Thereby, the pattern can be drawn on the drawing material M.

For example, the sub-deflector control unit 35 generates a scanning signal based on pattern information and a clock signal from the information processing device 50. The scanning signal includes pattern information and scan frequency information. The sub-deflector control section 35 supplies the generated scanning signal to the sub-deflector 19a. Thereby, the sub-deflector 19a operates based on the scanning signal, and a desired pattern is drawn at a desired scanning frequency.

The main deflector control section 36 controls the main deflector 19b. The main deflector control unit 36 receives pattern information from the information processing device 50, generates a deflection signal based on the pattern information, and supplies it to the main deflector 19b. Thereby, the main deflector 19b operates according to the deflection signal, and a desired position of the drawing material M is irradiated with the electron beam.

The height measurement control section 37 controls the height measurement device 21. Further, the height measurement control unit 37 acquires information on the height of the drawing material M measured by the height measuring device 21 and sends it to the information processing device 50 .

The functions of the high voltage control section 30, blanking control section 31, lens control section 32, scan frequency calculation section 33, sub-deflector control section 35, main deflector control section 36, and height measurement control section 37 are, for example, It may be realized by a general-purpose circuit such as a microcontroller or a microprocessor that operates according to a program, or it may be realized by a dedicated circuit such as an ASIC (application specific integrated circuit).

The ammeter 38 measures the beam current incident on the Faraday cup 22. The beam current measured by the ammeter 38 is sent to the information processing device 50.

Stage control device 39 operates stage 20. The stage 20 has a movement mechanism that moves the drawing material M in the horizontal direction. The stage control device 39 operates the moving mechanism of the stage 20 to move the drawing material M to the stage 20 in the horizontal direction.

The high voltage control section 30, the blanking control section 31, the lens control section 32, the scan frequency calculation section 33, the sub-deflector control section 35, the main deflector control section 36, the height measurement control section 37, and the stage control device 39 are , is controlled by the information processing device 50.

The drawing control unit 40 controls the entire operation of the electron beam drawing apparatus 100 via the information processing device 50. The drawing control unit 40 can be realized, for example, by using hardware such as various processors (CPU (Central Processing Unit), DSP (digital signal processor), etc.) and executing a program stored in a storage device.

The information processing device 50 includes a processing section 52, an operation section 54, and a storage section 56.

The operation unit 54 is for the user to input operation information, and outputs the input operation information to the processing unit 52. The functions of the operation unit 54 can be realized by hardware such as a keyboard, a mouse, buttons, and a touch pad.

The storage unit 56 stores programs and various data for making the computer function as each part of the processing unit 52. The storage unit 56 also functions as a work area for the processing unit 52. The function of the storage unit 56 can be realized by a hard disk, RAM (Random Access Memory), or the like.

The storage unit 56 stores pattern data. The pattern data includes data of a plurality of partial patterns that constitute a pattern drawn on the drawing material M. The partial pattern data includes information on the position of the partial pattern, information on the shape of the partial pattern, and information on the size of the partial pattern. Furthermore, the storage unit 56 stores drawing conditions. The drawing conditions include shot time conditions set for each of the plurality of partial patterns. Further, the drawing conditions include beam current and the like.

FIG. 2 is a diagram for explaining pattern data D of pattern 2 drawn on drawing material M. FIG. 2 shows a pattern 2 drawn in the main deflection area A1.

The main deflection area A1 is an area where the electron beam can be deflected by the main deflector 19b. The sub-deflection area A2 is an area where the electron beam can be deflected by the sub-deflector 19a. In the electron beam drawing apparatus 100, the main deflector 19b deflects the electron beam to the origin position of the sub-deflection area A2, and the sub-deflector 19a draws the partial pattern 4 in the sub-deflection area A2. When the drawing of the partial pattern 4 in the sub-deflection area A2 is completed, the main deflector 19b deflects the electron beam to the origin position of the next sub-deflection area A2. By repeating this, pattern 2 can be drawn in the main deflection area A1.

As shown in FIG. 2, the pattern 2 is composed of a plurality of partial patterns 4. The partial pattern 4 is, for example, a pattern obtained by dividing the pattern 2 into standard shapes such as trapezoids and rectangles. Drawing of pattern 2 is performed for each partial pattern 4. The partial pattern 4 is drawn, for example, by scanning an area of the shape and size specified by the pattern data D at a position specified by the pattern data D with an electron beam. The scanning speed of the electron beam when drawing one partial pattern 4 is constant.

Here, when drawing a pattern with an electron beam, the required dose differs for each partial pattern 4 to be drawn in order to correct the proximity effect. Therefore, the shot time conditions differ for each partial pattern 4. The shot time condition is the time per shot of the electron beam. That is, it is the time that the electron beam stays at one point. The scanning speed of the electron beam, that is, the scanning frequency can be determined from the shot time conditions. Within one main deflection area A1, if the shot time conditions are the same, the scan frequencies will be the same.

Note that the proximity effect is a phenomenon in which pattern dimensional errors occur when the resist is exposed to light by backscattered electrons that have passed through the resist and been scattered on the substrate surface.

In FIG. 2, differences in shot time conditions set for partial pattern 4 are represented by differences in hatching. That is, partial patterns 4 for which the same shot time is set are given the same hatching.

The processing unit 52 shown in FIG. 1 performs processing for drawing a pattern. The functions of the processing unit 52 can be realized by executing a program using hardware such as various processors (CPU, DSP, etc.). The processing section 52 includes a pattern data generation section 520 and a sorting processing section 522.

The pattern data generation unit 520 generates a plurality of partial pattern data by extracting partial patterns 4 having the same shot time condition from the pattern data D.

The sort processing unit 522 arranges the partial patterns 4 included in the plurality of partial pattern data generated by the pattern data generation unit 520 in the order of drawing, and stores them in the storage unit 56.

Details of the processing of the pattern data generation section 520 and the processing of the sorting processing section 522 will be explained in "3. Operation of the electron beam lithography apparatus" described later.

2. Clock Signal Output Unit FIG. 3 is a diagram showing the configuration of the clock signal output unit 34.

The clock signal output section 34 includes a control circuit 340 and a clock generation circuit 342, as shown in FIG.

The control circuit 340 receives information on the scan frequency determined by the scan frequency calculation section 33. The control circuit 340 generates setting data for generating a clock signal with a frequency corresponding to the scan frequency determined by the scan frequency calculation unit 33. The control circuit 340 sets setting data to the clock generation circuit 342. Thereby, the clock generation circuit 342 generates a clock signal with a frequency corresponding to the scan frequency. For example, the clock generation circuit 342 generates a clock signal having the same frequency as the scan frequency determined by the scan frequency calculation unit 33.

The control circuit 340 uses the enable signal to cause the clock generation circuit 342 to stop generating clock signals while the setting data is being set in the clock generation circuit 342. The control circuit 340 outputs the clock signal generated by the clock generation circuit 342 to the sub-deflector control section 35.

Clock generation circuit 342 generates a clock signal. The clock generation circuit 342 is, for example, a PLL circuit.

Note that the control circuit 340 and the scan frequency calculation section 33 may be configured by one FPGA (field programmable gate array).

3. Operation of electron beam lithography apparatus The operation of the electron beam lithography apparatus 100 will be explained. FIG. 4 is a flowchart showing an example of the operation of the electron beam lithography apparatus 100. Below, a case will be described in which pattern 2 is drawn in main deflection area A1.

When the drawing control section 40 receives an instruction to start the process of drawing the pattern 2 on the drawing material M, it operates each section constituting the electron beam drawing apparatus 100.

First, the pattern data generation unit 520 obtains pattern data D of pattern 2 (S100).

The pattern data generation unit 520 reads pattern data D of pattern 2 from the storage unit 56. The pattern data D includes data of a plurality of partial patterns 4 forming the pattern 2. The pattern data generation unit 520 further reads drawing conditions from the storage unit 56. The drawing conditions include shot time conditions set for each of the plurality of partial patterns 4.

Next, the pattern data generation unit 520 generates a plurality of partial pattern data by extracting partial patterns 4 having the same shot time condition from the pattern data D (S102).

FIG. 5 is a diagram for explaining the processing of the pattern data generation section 520.

As shown in FIG. 5, the pattern data generation unit 520 extracts partial pattern 4 having the same shot time condition from pattern 2, and generates partial pattern data. The partial pattern data is data of partial pattern 4 set to the same shot time condition. The partial pattern data includes information on the position of the partial pattern, information on the shape of the partial pattern, and information on the size of the partial pattern.

In the example shown in FIG. 5, from the pattern data D, four partial pattern data (first partial pattern data D-1, second partial pattern data D-2, third partial pattern data D-3, and fourth partial pattern data D-4) is generated.

The first partial pattern data D-1 is data of a partial pattern 4 whose shot time is set to the first shot time among the plurality of partial patterns 4 constituting the pattern 2. The second partial pattern data D-2 is data of a partial pattern 4 whose shot time is set to the second shot time among the plurality of partial patterns 4 forming the pattern 2. The third partial pattern data D-3 is data of a partial pattern 4 whose shot time is set to the third shot time among the plurality of partial patterns 4 forming the pattern 2. The fourth partial pattern data D-4 is data of a partial pattern 4 whose shot time is set to the fourth shot time among the plurality of partial patterns 4 constituting the pattern 2.

Next, the sort processing unit 522 arranges the partial patterns 4 for each partial pattern data and stores them in the storage unit 56 (S104).

FIG. 6 is a diagram for explaining the processing of the sort processing unit 522.

As shown in FIG. 6, the sort processing unit 522 sorts the partial pattern 4 included in the first partial pattern data D-1, the partial pattern 4 included in the second partial pattern data D-2, and the third partial pattern data D-. The partial patterns 4 are arranged in the order of the partial patterns 4 included in the fourth partial pattern data D-4 and the partial patterns 4 included in the fourth partial pattern data D-4.

That is, after arranging all the partial patterns 4 included in the first partial pattern data D-1, the sorting processing unit 522 arranges all the partial patterns 4 included in the second partial pattern data D-2. Further, after all the partial patterns 4 included in the second partial pattern data D-2 are arranged, all the partial patterns 4 included in the third partial pattern data D-3 are arranged. Further, after all the partial patterns 4 included in the third partial pattern data D-3 are arranged, all the partial patterns 4 included in the fourth partial pattern data D-4 are arranged.

Through the above processing, a partial pattern sequence 6 is generated. In the partial pattern row 6, partial patterns 4 having the same shot time condition are consecutively arranged. That is, in the partial pattern row 6, partial patterns 4 drawn at the same scan frequency are consecutively arranged. The data of the partial pattern sequence 6 is stored in the storage section 56.

Although not shown, the electron beam lithography apparatus 100 may have a storage section for storing the partial pattern array 6, separate from the storage section 56. For example, the electron beam lithography apparatus 100 may have a dedicated storage section for storing the partial pattern array 6. The function of the storage unit may be realized by a hard disk, RAM, or the like.

The scan frequency calculation unit 33 calculates the scan frequency based on the shot time condition of the first (N=1) partial pattern 4 in the partial pattern sequence 6 (S106).

The scan frequency can be determined from the beam current and shot time, for example. The beam current is measured, for example, before writing the main deflection region A1. For example, the beam current is measured for each main deflection region A1. That is, within one main deflection region A1, the beam current conditions when drawing the partial pattern 4 are constant. Information on the beam current is included in the drawing conditions and is stored in the storage unit 56. Note that the scan frequency calculation unit 33 may calculate the scan frequency only from the shot time condition, or may calculate the scan frequency by considering not only the shot time condition but also other drawing conditions.

When the scan frequency calculation unit 33 calculates the scan frequency, the clock signal output unit 34 outputs a clock signal having a frequency corresponding to the scan frequency calculated by the scan frequency calculation unit 33.

The sub-deflector control unit 35 and the main deflector control unit 36 cause the deflector 19 to draw the first partial pattern 4 of the partial pattern array 6 (S108).

For example, first, the main deflector control unit 36 causes the main deflector 19b to deflect the electron beam to the origin position of the sub-deflection area A2 including the first partial pattern 4. Next, the sub-deflector control unit 35 causes the sub-deflector 19a to draw the first partial pattern 4. At this time, the sub-deflector control section 35 operates the sub-deflector 19a based on the clock signal. Thereby, the electron beam is scanned at the scan frequency determined by the scan frequency calculation section 33. Through the above processing, the first partial pattern 4 can be drawn.

Next, the scan frequency calculation unit 33 calculates the scan frequency based on the shot time condition of the second (N=2) partial pattern 4 of the partial pattern sequence 6 (S106), and the control circuit 340 The frequency is compared with the scan frequency of the previous drawing, and if different, setting data is set to the clock generation circuit 342 (scan frequency switching), and if the same, setting data is set to the clock generation circuit 342. Without setting, use the same clock signal as the previous drawing. The sub-deflector control unit 35 and the main deflector control unit 36 cause the deflector 19 to draw the second partial pattern 4 (S108).

Until the scan frequency calculation (S106) and the drawing process (S108) are performed on the last partial pattern 4 (Mth partial pattern) of the partial pattern sequence 6 (until N=M), the scan frequency is Calculation (S106) and drawing processing (S108) are repeatedly performed.

The sub-deflector control unit 35 and the main deflector control unit 36 cause the deflector 19 to draw the M-th partial pattern 4, and when the drawing of the M-th partial pattern 4 is completed (Yes in S108), the drawing control is performed. The unit 40 ends the process of drawing pattern 2.

Through the above processing, pattern 2 can be drawn in the main deflection area A1.

In this way, in the electron beam drawing apparatus 100, after all the partial patterns 4 included in the first partial pattern data D-1 are drawn, all the partial patterns 4 included in the second partial pattern data D-2 are drawn. . Similarly, after all the partial patterns 4 included in the second partial pattern data D-2 are drawn, all the partial patterns 4 included in the third partial pattern data D-3 are drawn. Similarly, after all the partial patterns 4 included in the third partial pattern data D-3 are drawn, all the partial patterns 4 included in the fourth partial pattern data D-4 are drawn.

As a result, the number of times the scan frequency is switched is three.

Note that by repeating the movement of the main deflection area A1 by moving the drawing material M on the stage 20 and the drawing of the pattern on the main deflection area A1 shown in FIG. can be drawn.

4. Effects In the electron beam lithography apparatus 100, the pattern data generation unit 520 generates a plurality of partial pattern data by extracting partial patterns 4 having the same shot time condition from the pattern data D. Further, the scan frequency calculation unit 33 calculates a first scan frequency, which is a scan frequency when drawing the partial pattern 4 included in the first partial pattern data D-1, based on the shot time condition of the first partial pattern data D-1. A second scan frequency, which is a scan frequency when drawing the partial pattern 4 included in the second partial pattern data D-2, based on the process of determining the scan frequency and the shot time condition of the second partial pattern data D-2. Perform the process to obtain . Further, the sub-deflector control unit 35 causes the deflector 19 to draw the partial pattern 4 included in the first partial pattern data D-1 at the first scan frequency, and causes the deflector 19 to write the second partial pattern data D-1. A process of drawing the partial pattern 4 included in D-2 at the second scan frequency is performed.

In this manner, the electron beam drawing apparatus 100 generates a plurality of partial pattern data by extracting partial patterns 4 having the same shot time condition, and draws the partial pattern 4 for each partial pattern data. That is, in the electron beam drawing apparatus 100, partial patterns 4 drawn at the same scan frequency are drawn continuously. Therefore, in the electron beam lithography apparatus 100, the number of times the scan frequency is switched can be reduced, and the throughput of lithography can be improved.

FIG. 7 is a diagram illustrating an example of a method for drawing pattern 2.

For example, as shown in FIG. 7, after all partial patterns 4 in one sub-deflection area A2 are drawn, all partial patterns 4 in the adjacent sub-deflection area A2 are repeatedly drawn, and the main deflection area A1 Draw pattern 2 on. In this case, the partial pattern 4 is drawn for each sub-deflection area A2. The partial pattern array 8 at this time is shown in FIG.

When drawing the partial pattern 4 for each sub-deflection area A2, as shown in FIG. 8, the number of times the scan frequency is switched increases. In the example shown in FIG. 8, the scan frequency must be switched every time one partial pattern 4 is drawn.

On the other hand, in the electron beam lithography apparatus 100, as described above, the partial patterns 4 drawn at the same scan frequency are drawn continuously, so when drawing the partial patterns 4 for each sub-deflection area A2, Compared to , the number of times the scan frequency must be switched can be reduced. This allows the clock signal output section 34 to reduce the number of times the frequency of the clock signal is switched. Therefore, the electron beam lithography apparatus 100 can improve the lithography throughput.

In the electron beam drawing apparatus 100, the sub-deflector control section 35 and the main deflector control section 36 cause the deflector 19 to draw all the partial patterns 4 included in the first partial pattern data D-1, and then write the partial patterns 4 included in the first partial pattern data D-1. All partial patterns 4 included in the 2-part pattern data D-2 are drawn. Therefore, in the electron beam lithography apparatus 100, the number of times the scan frequency is switched can be reduced, and the throughput of lithography can be improved.

5. Variations 5.1. First modification 5.1.1. Configuration of Electron Beam Lithography Apparatus The electron beam lithography apparatus according to the first modification differs from the electron beam lithography apparatus 100 described above in the configuration of the clock signal output section 34. Below, points different from the example of the electron beam lithography apparatus 100 described above will be explained, and explanations of similar points will be omitted.

FIG. 9 is a diagram showing the configuration of the clock signal output section 34 of the electron beam lithography apparatus according to the first modification.

The clock signal output section 34 includes a control circuit 340, a first clock generation circuit 342a, a second clock generation circuit 342b, and a selector 344.

The first clock generation circuit 342a is a circuit that generates a low frequency clock signal. The second clock generation circuit 342b is a circuit that generates a high frequency clock signal. That is, the frequency of the clock signal generated by the second clock generation circuit 342b is higher than the frequency of the clock signal generated by the first clock generation circuit 342a.

The first clock generation circuit 342a is, for example, a ring oscillator. The second clock generation circuit 342b is, for example, a PLL circuit. Since the operating speed of a ring oscillator depends on the delay time of the delay IC and logic circuit, the frequency of the clock signal that can be generated is, for example, 100 MHz or less. On the other hand, a PLL circuit can generate a clock signal with a high frequency of about several GHz.

The switching time for switching the frequency of the clock signal of the second clock generation circuit 342b is longer than the switching time for switching the frequency of the clock signal of the first clock generation circuit 342a.

Switching time is the sum of program time and stabilization time. The program time is the time for setting the frequency in the clock generation circuit. The stabilization time is the time from when a frequency is set in the clock generation circuit until the clock generation circuit stably outputs a clock signal of the set frequency. Due to the characteristics of the PLL circuit, the switching time of the PLL circuit is longer than the switching time of the ring oscillator.

The first clock generation circuit 342a and the second clock generation circuit 342b are connected to the input of the selector 344.

The selector 344 selects the clock signal generated by the first clock generation circuit 342a or the clock signal generated by the second clock generation circuit 342b. The operation of selector 344 is controlled by control circuit 340. The clock signal selected by selector 344 is output from control circuit 340.

5.1.2. Operation of the electron beam lithography apparatus FIG. 10 is a flowchart showing an example of the operation of the electron beam lithography apparatus according to the second modification.

Before starting writing, the drawing control unit 40 irradiates the Faraday cup 22 with an electron beam and measures the beam current with the ammeter 38 (S200).

The pattern data generation unit 520 acquires pattern data D and drawing conditions of pattern 2 to be drawn in the main deflection area A1 (S202). The drawing conditions include shot time conditions set for each of the plurality of partial patterns 4 making up the pattern 2.

The scan frequency calculation unit 33 calculates the scan frequency for each of the plurality of partial patterns 4 based on the shot time condition and the beam current, and determines the maximum value of the scan frequency (S204).

The drawing control unit 40 compares the maximum value of the scan frequency with a preset threshold (S206).

The threshold value is set, for example, to the maximum frequency of the clock signal that can be generated by the first clock generation circuit 342a.

If the maximum value of the scan frequency is less than or equal to the threshold (Yes in S208), the pattern data generation unit 520 does not generate partial pattern data, and the sorting unit 522 arranges partial patterns 4 for each sub-deflection area A2, for example. Thus, a partial pattern sequence 8 shown in FIG. 8 is generated. Thereby, as shown in FIG. 7, partial pattern 4 is drawn for each sub-deflection area A2 (S210).

Specifically, the scan frequency calculation unit 33 calculates the scan frequency based on the shot time condition of the first partial pattern 4 of the partial pattern sequence 8. The clock signal output section 34 outputs a clock signal having a frequency corresponding to the scan frequency determined by the scan frequency calculation section 33. At this time, in the clock signal output section 34, the selector 344 selects the clock signal generated by the first clock generation circuit 342a. The sub-deflector control unit 35 and the main deflector control unit 36 cause the deflector 19 to draw the first partial pattern 4 of the partial pattern array 8 .

The drawing of the second and subsequent partial patterns 4 in the partial pattern array 8 is also performed in the same manner as the drawing of the first partial pattern 4. Through the above processing, pattern 2 can be drawn in the main deflection area A1.

If the maximum value of the scan frequency is greater than the threshold (No in S208), the pattern data generation unit 520 extracts a partial pattern 4 whose scan frequency is equal to or less than the threshold from the pattern data D, as shown in FIG. First partial pattern data D-1 is generated. Further, the pattern data generation unit 520 extracts a partial pattern 4 whose scanning frequency is higher than a threshold value from the pattern data D, extracts a partial pattern 4 for each shot time condition from the extracted partial pattern 4, and generates a plurality of partial patterns. Pattern data (second partial pattern data D-2, third partial pattern data D-3) is generated (S212).

The sort processing unit 522 arranges the partial patterns 4 for each partial pattern data and generates a partial pattern sequence. For example, the sorting processing unit 522 selects a partial pattern 4 included in the first partial pattern data D-1, a partial pattern 4 included in the second partial pattern data D-2, and a portion included in the third partial pattern data D-3. Partial patterns 4 are arranged in the order of pattern 4.

Note that the sort processing unit 522 selects partial patterns 4 included in the second partial pattern data D-2, partial patterns 4 included in the third partial pattern data D-3, and portions included in the first partial pattern data D-1. Partial patterns 4 may be arranged in the order of pattern 4.

The scan frequency calculation unit 33 calculates the scan frequency in the order of the generated partial pattern sequences, and the sub-deflector control unit 35 and the main deflector control unit 36 draw the partial patterns 4 in the order of the generated partial pattern sequences. (S214).

Specifically, the scan frequency calculation unit 33 calculates the scan frequency based on the shot time condition of the first partial pattern 4 in the partial pattern sequence. Here, if the scan frequency of the first partial pattern 4 is less than or equal to the threshold value, the selector 344 selects the clock signal generated by the first clock generation circuit 342a. Further, when the scan frequency of the first partial pattern 4 in the partial pattern sequence is higher than the threshold value, the selector 344 selects the clock signal generated by the second clock generation circuit 342b. The sub-deflector control unit 35 and the main deflector control unit 36 cause the deflector 19 to draw the first partial pattern 4 in the partial pattern sequence.

Drawing of the second and subsequent partial patterns 4 in the partial pattern sequence is also performed in the same manner as the drawing of the first partial pattern 4. Through the above processing, pattern 2 can be drawn in the main deflection area A1.

5.1.3. Effects In the electron beam lithography apparatus according to the first modification, the clock signal output unit 34 includes a first clock generation circuit 342a and a second clock generation circuit 342b, and the second clock generation circuit 342b generates a clock signal. The frequency of the clock signal is higher than the frequency of the clock signal generated by the first clock generation circuit 342a, and the switching time for switching the frequency of the clock signal of the second clock generation circuit 342b is higher than the frequency of the clock signal generated by the first clock generation circuit 342a. It is longer than the switching time for switching the signal frequency.

Therefore, in the electron beam lithography apparatus according to the first modification, when drawing at a low scan frequency, the first clock generation circuit 342a with a short switching time is used. Therefore, when drawing at a low scan frequency, the process of generating partial pattern data by the pattern data generation unit 520 is not necessary, and the drawing throughput can be improved. Further, the electron beam lithography apparatus according to the first modification performs the same operation as the above-described electron beam lithography apparatus 100 when performing lithography at a high scan frequency, so that the lithography throughput can be improved.

5.2. Second Modification The electron beam lithography apparatus according to the second modification differs from the above-described electron beam lithography apparatus 100 in the configuration of the clock signal output section 34. Below, points different from the example of the electron beam lithography apparatus 100 and the example of the electron beam lithography apparatus according to the first modification described above will be explained, and explanations of the same points will be omitted.

In the electron beam lithography apparatus according to the first modified example shown in FIG. 9, the first clock generation circuit 342a was a ring oscillator, and the second clock generation circuit 342b was a PLL circuit.

In contrast, in the electron beam lithography apparatus according to the second modification, the first clock generation circuit 342a and the second clock generation circuit 342b are PLL circuits. Hereinafter, an electron beam lithography apparatus according to a second modification will be described with reference to FIG. 9.

In the clock signal output section 34, frequencies can be set individually for the first clock generation circuit 342a and the second clock generation circuit 342b. That is, while the first clock generation circuit 342a is generating a clock signal, the frequency can be set in the second clock generation circuit 342b. Therefore, in the electron beam lithography apparatus according to the second modification, the waiting time when switching the scan frequency can be shortened.

For example, when drawing the partial pattern array 6 shown in FIG. While the partial pattern 4 is being drawn, processing for setting the frequency corresponding to the second scan frequency in the second clock generation circuit 342b is started.

Further, the control circuit 340 causes the second clock generation circuit 342b to generate a clock signal corresponding to the second scan frequency, and while the partial pattern 4 included in the second partial pattern data D-2 is being drawn, A process of setting a frequency corresponding to the third scan frequency in the first clock generation circuit 342a is started.

By repeating this process, the waiting time when switching the scan frequency can be reduced.

Note that although the case where there are two clock generation circuits has been described above, the number of clock generation circuits may be two or more. By increasing the number of clock generation circuits, it is possible to further reduce the waiting time when switching the scan frequency.

Note that the above-described embodiments and modifications are merely examples, and the present invention is not limited thereto. For example, each embodiment and each modification can be combined as appropriate.

The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as those described in the embodiments. Substantially the same configuration is, for example, a configuration with the same function, method, and result, or a configuration with the same purpose and effect. Further, the present invention includes a configuration in which non-essential parts of the configuration described in the embodiments are replaced. Further, the present invention includes a configuration that has the same effects or a configuration that can achieve the same purpose as the configuration described in the embodiment. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

2... Pattern, 4... Partial pattern, 6... Partial pattern row, 8... Partial pattern row, 10... Electron source, 11... Accelerating electrode, 12... Blanking aperture, 13... Blanker, 14... Electrostatic lens, 15a... Capacitor Lens, 15b...Condenser lens, 16...Objective aperture, 17...Objective lens, 18...Astigmatism corrector, 19...Deflector, 19a...Sub deflector, 19b...Main deflector, 20...Stage, 21...Height Measuring instrument, 22... Faraday cup, 30... High voltage control section, 31... Blanking control section, 32... Lens control section, 33... Scan frequency calculation section, 34... Clock signal output section, 35... Sub-deflector control section, 36... Main deflector control section, 37... Height measurement control section, 38... Ammeter, 39... Stage control device, 40... Drawing control section, 50... Information processing device, 52... Processing section, 54... Operation section, 56 ...Storage unit, 100...Electron beam drawing device, 340...Control circuit, 342...Clock generation circuit, 342a...First clock generation circuit, 342b...Second clock generation circuit, 344...Selector, 520...Pattern data generation unit, 522 …Sort processing section

Claims (6)

A charged particle beam drawing device that draws a pattern on a drawing material with a charged particle beam,
a charged particle beam source that generates the charged particle beam;
a deflector that deflects the charged particle beam;
a scan frequency calculation unit that calculates the scan frequency;
a clock signal output section that switches the frequency of the clock signal according to the scan frequency;
a deflector control unit that causes the deflector to deflect the charged particle beam based on the clock signal;
a storage unit storing pattern data of the pattern made up of a plurality of partial patterns and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
a pattern data generation unit that generates a plurality of partial pattern data by extracting the partial patterns having the same shot time condition from the pattern data;
a sorting processing unit that arranges the plurality of partial patterns for each of the partial pattern data to generate a partial pattern sequence;
including;
performing a process of drawing the partial patterns in the order in which they are arranged in the partial pattern column;
The process of drawing the partial pattern is as follows:
a process in which the scan frequency calculation unit calculates the scan frequency based on the shot time condition;
a process in which the deflector control unit causes the deflector to draw the partial pattern at the scan frequency determined by the scan frequency calculation unit ;
A charged particle beam lithography device including : In claim 1 ,
The clock signal output section includes:
a first clock generation circuit;
a second clock generation circuit;
a selector that selects a clock signal generated by the first clock generation circuit or a clock signal generated by the second clock generation circuit;
has
The frequency of the clock signal generated by the second clock generation circuit is higher than the frequency of the clock signal generated by the first clock generation circuit,
A charged particle beam lithography apparatus, wherein a switching time for switching the frequency of the clock signal of the second clock generation circuit is longer than a switching time for switching the frequency of the clock signal of the first clock generation circuit. In claim 2,
The pattern data generation unit includes:
extracting a partial pattern in which the scan frequency is less than or equal to a threshold value from the pattern data to generate partial pattern data;
generating a plurality of partial pattern data by extracting a partial pattern in which the scanning frequency is higher than the threshold value from the pattern data, and extracting a partial pattern in which the shot time condition is the same from the extracted partial pattern;
The sorting processing unit generates a partial pattern sequence by arranging the plurality of partial patterns for each of the partial pattern data generated by the pattern data generation unit,
The process of drawing the partial pattern is as follows:
If the scan frequency is less than or equal to the threshold, the selector selects the clock signal generated by the first clock generation circuit, and if the scan frequency is greater than the threshold, the selector selects the clock signal generated by the second clock generation circuit. including a process of selecting the generated clock signal;
The deflector control unit is a charged particle beam lithography device that causes the deflector to draw the partial pattern based on the selected clock signal. In claim 1,
The clock signal output section includes:
multiple clock generation circuits,
a control circuit that sets a frequency of a clock signal for each of the plurality of clock generation circuits;
a selector that selects one of the clock signals generated by the plurality of clock generation circuits;
A charged particle beam lithography device having: A drawing method for drawing a pattern on a drawing material using a charged particle beam,
acquiring pattern data of the pattern made up of a plurality of partial patterns, and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
generating a plurality of partial pattern data by extracting the partial patterns having the same shot time condition from the pattern data;
arranging the plurality of partial patterns according to the partial pattern data to generate a partial pattern sequence;
drawing the partial patterns in the order arranged in the partial pattern row;
including;
The step of drawing the partial pattern includes:
determining a scan frequency when drawing the partial pattern based on the shot time condition;
causing a deflector that deflects the charged particle beam to draw the partial pattern at the scanning frequency;
Including how to draw. A drawing method for drawing a pattern on a drawing material using a charged particle beam,
acquiring pattern data of the pattern made up of a plurality of partial patterns, and drawing conditions including shot time conditions set for each of the plurality of partial patterns;
in each of the plurality of partial patterns, determining a scan frequency when drawing the partial pattern based on the shot time condition;
A partial pattern in which the scan frequency is equal to or less than a threshold is extracted from the pattern data to generate partial pattern data, a partial pattern in which the scan frequency is greater than the threshold is extracted from the pattern data, and the partial pattern is extracted from the extracted partial pattern. generating a plurality of partial pattern data by extracting partial patterns having the same shot time condition;
arranging the plurality of partial patterns for each of the partial pattern data to generate a partial pattern sequence;
drawing the partial patterns in the order arranged in the partial pattern row;
including;
The step of drawing the partial pattern includes:
determining the scan frequency when drawing the partial pattern based on the shot time condition;
causing a deflector that deflects the charged particle beam to draw the partial pattern at the scanning frequency;
including;
In the step of causing the deflector to draw the partial pattern, the charged particle beam is deflected by the deflector based on the clock signal output from a clock signal output unit that switches the frequency of a clock signal according to the scan frequency. let me,
The clock signal output section includes:
a first clock generation circuit;
a second clock generation circuit;
a selector that selects a clock signal generated by the first clock generation circuit or a clock signal generated by the second clock generation circuit;
has
The frequency of the clock signal generated by the second clock generation circuit is higher than the frequency of the clock signal generated by the first clock generation circuit,
A switching time for switching the frequency of the clock signal of the second clock generation circuit is longer than a switching time for switching the frequency of the clock signal of the first clock generation circuit,
In the step of drawing the partial pattern on the deflector,
If the scan frequency is less than or equal to the threshold, the selector selects the clock signal generated by the first clock generation circuit, and if the scan frequency is greater than the threshold, the selector selects the clock signal generated by the second clock generation circuit. A drawing method that selects the generated clock signal.

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