JP2012069668A - Charged particle beam lithography apparatus and charged particle beam lithography method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable of drawing a pattern with higher dimensional accuracy.SOLUTION: A lithography apparatus 100 comprises: a scheduled drawing time calculation unit 52 which calculates a scheduled drawing time longer than a predicted drawing prediction time; a drawing control unit 72 which controls drawing operation along the scheduled drawing time; and a drawing unit 150 which is controlled by the drawing control unit 72 to perform drawing operation along the scheduled drawing time, and draws a pattern, by using a charged particle beam, on a sample coated with resist that changes the pattern dimensions depending on the elapsed time after drawing.

Description

  The present invention relates to a charged particle beam drawing apparatus and a charged particle beam drawing method, and for example, relates to a drawing apparatus and method for drawing a pattern on a resist whose pattern dimensions change according to a standing time after drawing.

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

  Here, in recent years, there is a chemically amplified resist as one of the resists frequently used for electron beam exposure. The chemically amplified resist has a problem that the optimum exposure amount changes depending on the exposure after exposure. In other words, when a chemically amplified resist is used for mask production, line width dimension (CD) fluctuations after drawing of a mask serving as a sample occur.

  Here, it is considered that the line width dimension (CD) variation after the mask drawing described above is due to the diffusion of the acid generated by the drawing. The diffusion of the acid occurs in the region of several tens of nm and is a rate of about 1.0 nm / h. Therefore, the drawing apparatus is required to be equipped with a time-dependent correction function. As one of them, the dose is corrected depending on the drawing time. For example, when the pattern drawn on the sample or the drawing order of the chips can be controlled, a pattern CD error due to time is predicted, and the dose Dose is changed in order to correct this (for example, see Patent Document 1).

  In order to perform such time-dependent dose correction, it is necessary to grasp the drawing time before drawing. Accordingly, the drawing apparatus predicts the drawing time using the pattern layout data to be drawn. However, there is a problem that a difference occurs between the predicted drawing time and the actual drawing time as the drawing process is started and drawing progresses. For this reason, there is a problem that if the drawing is performed with the dose corrected based on the drawing time, an error occurs in the pattern dimension.

JP 2008-034781 A

  As described above, as drawing processing is started and drawing progresses, there is a problem that a difference (gap) occurs between the drawing time predicted before drawing and the actual drawing time. For this reason, there is a problem that if the drawing is performed with the irradiation amount calculated based on the drawing time, an error occurs in the pattern dimension. However, a sufficient method for solving such a problem has not been established.

  Accordingly, an object of the present invention is to provide an apparatus and a method that can overcome such problems and can draw a pattern with a more accurate dimension.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
A planned drawing time calculation unit for calculating a planned drawing time longer than the predicted drawing predicted time;
A drawing control unit that controls drawing operations according to the planned drawing time;
A pattern is drawn using a charged particle beam on a sample coated with a resist that changes the pattern size according to the standing time after drawing while being controlled by the drawing control unit to perform a drawing operation along the planned drawing time. A drawing section;
It is provided with.

  In addition, when there is a request for an unscheduled operation when calculating the planned drawing time, the drawing control unit continues to perform control so that the drawing operation is continued along the planned drawing time without performing the operation. It is characterized by that.

  In addition, it is preferable that the planned drawing time calculation unit includes the transport time for transporting the sample to be drawn next after the drawing process for the drawing target sample is temporarily suspended in the planned drawing time.

A drawing time prediction unit for calculating a drawing prediction time;
A drift correction time calculation unit for calculating a drift correction time of a charged particle beam having an irregular execution interval using a drawing prediction time;
Further comprising
The planned drawing time calculation unit preferably includes a drift correction time for performing drift correction of the charged particle beam in the drift correction time calculated by temporarily interrupting the drawing process for the sample to be drawn.

The charged particle beam drawing method of one embodiment of the present invention includes:
Calculating a planned drawing time longer than the predicted drawing prediction time;
A process of drawing a pattern using a charged particle beam on a sample coated with a resist that changes a pattern size according to a standing time after drawing while controlling so that a drawing operation is performed according to a planned drawing time;
It is provided with.

  According to one embodiment of the present invention, a pattern can be drawn with a more accurate dimension.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. FIG. 4 is a flowchart showing main steps of the drawing method according to Embodiment 1. FIG. 6 is a conceptual diagram illustrating a configuration in a case where the progress of a drawing operation is managed by a control computer on the shot generation side in the first embodiment. FIG. 3 is a conceptual diagram illustrating a configuration in a case where progress of a drawing operation is managed by a control computer on the drawing control side in the first embodiment. FIG. 6 is a flowchart when performing mask transport processing in the first embodiment. 6 is a conceptual diagram for explaining a request rejection method according to Embodiment 1. FIG. FIG. 10 is a conceptual diagram for explaining a difference in drawing time depending on the presence or absence of drift correction in the second embodiment. FIG. 10 is another conceptual diagram for explaining a difference in drawing time depending on the presence or absence of drift correction in the second embodiment. FIG. 10 is a conceptual diagram for explaining an interval between drawing pauses due to drift correction and conveyance processing in the second embodiment. FIG. 10 is a conceptual diagram for explaining a drawing pause interval when events such as drift correction and conveyance processing occur simultaneously in the second embodiment. 6 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 2. FIG. FIG. 10 is a flowchart showing main steps of a drawing method according to Embodiment 2. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus.

  Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and a beam using charged particles such as an ion beam may be used. Further, a variable shaping type drawing apparatus will be described as an example of the charged particle beam apparatus.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The drawing apparatus 100 is an example of a charged particle beam drawing apparatus. In particular, it is an example of a variable shaping type (VSB type) drawing apparatus. The drawing unit 150 includes an electron column 102 and a drawing chamber 103. In the electron column 102, there are an electron gun 201, an illumination lens 202, a blanking deflector (blanker) 212, a blanking aperture 214, a first shaping aperture 203, a projection lens 204, a deflector 205, and a second shaping aperture. 206, an objective lens 207, and a deflector 208 are arranged. An XY stage 105 that can move at least in the XY direction is disposed in the drawing chamber 103. On the XY stage 105, a sample 101 to be drawn on which a resist is applied is disposed. The sample 101 includes an exposure mask and a silicon wafer for manufacturing a semiconductor device. Masks include mask blanks.

  The control unit 160 includes memories 51, 61, 71, control computers 110, 112, 114, an interface (I / F) circuit 111, a stage drive control circuit 116, a deflection control circuit 120, and a DAC (digital / analog converter) amplifier unit 130. (Deflection amplifier) and storage devices 140, 142, and 144 such as magnetic disk devices. The memories 51, 61, 71, the control computers 110, 112, 114, the interface (I / F) circuit 111, the stage drive control circuit 116, the deflection control circuit 120, and the storage devices 140, 142, 144 such as a magnetic disk device are They are connected to each other via a bus 118. A DAC amplifier unit 130 is connected to the deflection control circuit 120. The DAC amplifier unit 130 is connected to the blanking deflector 212.

  A digital signal for blanking control is output from the deflection control circuit 120 to the DAC amplifier unit 130. The DAC amplifier unit 130 converts the digital signal into an analog signal, amplifies it, and applies it to the blanking deflector 212 as a deflection voltage. The electron beam 200 is deflected by such a deflection voltage, and a beam of each shot is formed.

  In the control computer 110, a drawing time prediction unit 50 and a planned drawing time calculation unit 52 are arranged. Each function such as the drawing time prediction unit 50 and the planned drawing time calculation unit 52 may be configured by software such as a program. Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. The input data necessary for the control computer 110 or the calculated result is stored in the memory 51 each time.

  Further, in the control computer 112, a shot data generation unit 60, a determination unit 62, and a command instruction unit 64 are arranged. Each function such as the shot data generation unit 60, the determination unit 62, and the command instruction unit 64 may be configured by software such as a program. Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. The input data necessary for the control computer 112 or the calculated result is stored in the memory 61 each time.

  In the control computer 114, a drawing management unit 70, a drawing process control unit 72, a determination unit 74, and an irradiation amount calculation unit 76 are arranged. Each function such as the drawing management unit 70, the drawing processing control unit 72, the determination unit 74, and the dose calculation unit 76 may be configured by software such as a program. Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. The input data necessary for the control computer 114 or the calculated result is stored in the memory 71 each time.

  In addition, drawing data is input from the outside and stored in the storage device 140.

  Here, FIG. 1 shows a configuration necessary for explaining the first embodiment. The drawing apparatus 100 may normally have other necessary configurations. For example, it goes without saying that each DAC amplifier unit for the deflector 205 and the deflector 208 is also provided.

  Conventionally, in the case of correcting the change in pattern dimensions due to leaving after drawing with a chemically amplified resist by the irradiation amount, first, the drawing time is predicted from the pattern layout, and the irradiation amount is calculated from the drawing time. That is, the normal drawing process time is predicted, and the irradiation amount is obtained according to the predicted time. However, when the drawing process is actually started, there may be a case where the scheduled drawing time is deviated. As described above, if the drawing time is predicted so as to match the drawing process in accordance with the performance on the apparatus side, a time difference is generated between the actual process. Therefore, in the first embodiment, instead of using the predicted drawing time according to the drawing processing, conversely, first, the planned drawing time is set, and the progress status of the actual drawing processing operation is displayed at the planned drawing time. Proceed to match. In other words, the other is adjusted to the drawing time calculated as “plan” instead of “forecast”. Thereby, it is possible to prevent a time lag between the planned drawing time and the actual processing time.

  FIG. 2 is a flowchart showing main steps of the drawing method according to the first embodiment. In FIG. 2, the drawing method in Embodiment 1 includes a drawing time prediction step (S102), a planned drawing time calculation unit (S110), a dose calculation step (S111), a drawing start processing step (S112), A series of steps of a determination step (S114), a drawing pause step (S116), a determination step (S118), a drawing restart processing step (S120), and a determination step (S122) are performed.

  First, the shot data generation unit 60 reads the drawing data from the storage device 140 and performs a plurality of stages of data conversion processing to generate shot data having a format unique to the apparatus. The generated shot data is sequentially stored in the storage device 144.

  In the drawing time prediction step (S102), the drawing time prediction unit 50 reads drawing data from the storage device 140, and predicts the drawing time before starting drawing based on the pattern layout. The drawing time can be calculated, for example, by multiplying the total number of shots by a shot cycle. Such processing is preferably performed in parallel with shot data generation.

As the planned drawing time calculation unit (S110), the planned drawing time calculation unit 52 calculates a planned drawing time longer than the predicted drawing prediction time. When the planned drawing time is longer than the actual drawing time, the drawing process can be paused halfway to match the actual drawing process with the planned drawing time. Also, the drawing progress can be advanced slowly. On the other hand, when the planned drawing time is shorter than the actual drawing time, it is necessary to speed up the actual drawing process, but this is difficult. Therefore, the planned drawing time is calculated so as to be always longer than the actual drawing time by adding the maximum error to the predicted drawing time and further multiplying by the safety factor. For example, the planned drawing time Tp can be defined by the following equation using the drawing prediction time Ts, the maximum error Em (%), and the safety factor Fs (%).
Tp = (Ts × Em / 100) · (Fs / 100)

As the dose calculation step (S111), the dose calculation unit 76 calculates the dose of the electron beam 200 using the calculated planned drawing time. For example, the irradiation amount of the beam of each shot is calculated as follows. First, the generated shot data is input, and a reference dose D0 for each shot is calculated. Further, the calculated planned drawing time is input, and the reference dose D0 for each shot is corrected using the time t from the drawing start time to the time when each shot is irradiated. Specifically, the corrected dose D (t) is defined by the following equation using a predetermined corrected dose amount δD, the planned drawing time Tp, and the 1 / e decay time constant Tλ.
D (t) = D0−δD · exp {(t−Tp) / Tλ}

  The irradiation amount of the beam of each shot is not limited to the above-described formula, and it is only necessary to correct the pattern dimension that changes depending on the standing time after drawing along the planned drawing time Tp. Further, the pattern change due to the standing time after drawing in the chemically amplified resist is saturated after a certain period of time has passed. Such saturation time varies depending on the type of resist. Therefore, if the pattern is left for more than the saturation time during drawing, the pattern dimension will not change thereafter. Needless to say, for shots in which the exposure time after drawing is equal to or greater than the saturation time, the dose is corrected so as to correct the pattern dimension that changes depending on the saturation time.

  As the drawing start processing step (S112), the drawing processing control unit 72 controls the drawing unit 150 via the deflection control circuit 120 and the like to start the drawing process. The drawing unit 150 draws a desired pattern on the sample 101 using the electron beam 200 having an irradiation amount obtained for each shot position. Specifically, it operates as follows. The deflection control circuit 120 receives shot data and outputs a digital signal for controlling the irradiation time for each shot to the DAC amplifier unit 130. The DAC amplifier unit 130 converts the digital signal into an analog signal, amplifies it, and applies it to the blanking deflector 212 as a deflection voltage.

  When the electron beam 200 emitted from the electron gun 201 (emission unit) passes through the blanking deflector 212, it is controlled by the blanking deflector 212 so as to pass through the blanking aperture 214 in the beam ON state. In the beam OFF state, the entire beam is deflected so as to be shielded by the blanking aperture 214. The electron beam 200 that has passed through the blanking aperture 214 until the beam is turned off after the beam is turned off becomes one shot of the electron beam. The blanking deflector 212 controls the direction of the passing electron beam 200 to alternately generate a beam ON state and a beam OFF state. For example, the voltage may be applied to the blanking deflector 212 when the beam is OFF, without applying a voltage when the beam is ON. The irradiation amount per shot of the electron beam 200 irradiated on the sample 101 is adjusted with the irradiation time T of each shot.

  As described above, the electron beam 200 of each shot generated by passing through the blanking deflector 212 and the blanking aperture 214 illuminates the entire first shaping aperture 203 having a rectangular hole, for example, a rectangular hole, by the illumination lens 202. To do. 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 shaping aperture 203 is projected onto the second shaping aperture 206 by the projection lens 204. The deflector 205 controls the deflection of the first aperture image on the second shaping aperture 206 and can change the beam shape and dimensions (variable shaping is performed). Such variable shaping is performed for each shot, and is usually shaped into different beam shapes and dimensions for each shot. The electron beam 200 of the second aperture image that has passed through the second shaping aperture 206 is focused by the objective lens 207, deflected by the deflector 208, and placed on the XY stage 105 that moves continuously. The desired position is irradiated. As described above, a plurality of shots of the electron beam 200 are sequentially deflected onto the sample 101 serving as the substrate by each deflector.

  Here, in the first embodiment, the drawing operation is controlled along the planned drawing time. However, it is determined whether the drawing progress is progressing along the planned drawing time, and if the drawing progress is too early, the drawing progress is performed. The processing for delaying can be performed by the control computer 112 or the control computer 114.

  FIG. 3 is a conceptual diagram showing a configuration when the progress of the drawing operation is managed by the control computer on the shot generation side in the first embodiment. In FIG. 3, the control computer 112 determines whether or not the drawing progress has progressed along the planned drawing time, and outputs a command for delaying the drawing progress if it is too early. Information on the planned drawing time stored in the storage device 142 is input by the control computer 112 via the drawing management unit 70. Alternatively, the image is output from the storage device 142 to the control computer 112 by the drawing management unit 70.

  As a determination step (S114), the determination unit 62 in the control computer 112 determines whether or not the drawing processing speed is faster than the planned drawing time. If it is fast, the process proceeds to S116, and if it is not fast, the process proceeds to S122.

  In the drawing pause process (S116), when the drawing processing speed is faster than the planned drawing time, the command instruction unit 64 in the control computer 112 sends a drawing pause status signal (pause) to the drawing management unit 70. Command). In addition, from the shot data generation unit 60, for example, a drawing preparation completion status indicating that generation of information and shot data such as frame information and compartment information has been completed and drawing preparation has been completed is completed. Is output to the drawing management unit 70.

  The drawing management unit 70 outputs information such as a drawing pause status signal to the drawing processing control unit 72. In response to the drawing pause status signal, the drawing processing control unit 72 controls the drawing processing to be suspended.

  As a determination step (S118), the determination unit 62 in the control computer 112 determines whether the drawing processing speed is faster than the plan based on the planned drawing time. If it is fast, the process returns to S116, and the command instruction unit 64 continues the drawing process temporarily by maintaining the drawing pause status signal. If the drawing processing speed is not faster than the planned drawing time, the process proceeds to S120.

  In the drawing restart processing step (S120), when the drawing processing speed is not faster than the planned drawing time, the command instruction unit 64 in the control computer 112 sends a drawing pause status signal ( (Pause command) release signal is output The drawing management unit 70 outputs information about the cancellation of the drawing pause status signal to the drawing processing control unit 72. The drawing process control unit 72 controls to resume the drawing process in response to the cancellation of the drawing pause status signal.

  As a determination step (S122), the drawing management unit 70 determines whether or not the drawing process has ended. If not, the drawing management unit 70 returns to S114, and if it has ended, the flow ends.

  FIG. 4 is a conceptual diagram showing a configuration when the progress of the drawing operation is managed by the control computer on the drawing control side in the first embodiment. In FIG. 4, the control computer 114 determines whether or not the progress of drawing is progressing along the planned drawing time, and performs processing for delaying the progress of drawing if it is too early. The drawing process control unit 72 inputs information on the planned drawing time stored in the storage device 142. In this case, the processing from the determination step (S114) to the drawing resumption processing step (S120) in FIG. 2 is as follows.

  As a determination step (S114), the determination unit 74 in the control computer 114 determines whether the drawing processing speed is faster than the plan based on the planned drawing time. If it is fast, the process proceeds to S116, and if it is not fast, the process proceeds to S122.

  Here, a plurality of chip patterns may be drawn on one mask. In such a case, there are chip patterns with different drawing conditions. Therefore, the chips having the same drawing condition are collected as one drawing group (drawing G), and drawing is performed for each drawing group. The drawing area of the sample 101 is virtually divided into a plurality of stripe areas in a strip shape, and drawing is performed for each stripe area. The drawing data is divided into data processing units for each predetermined area, and data processing is performed. Therefore, the determination time may be determined by, for example, a drawing group unit, a stripe unit, a drawing data processing unit, or the like.

  In the drawing pause process (S116), when the drawing processing speed is faster than the planned drawing time, the drawing process control unit 72 controls to temporarily stop the drawing process. Alternatively, the drawing processing control unit 72 may control the stage drive control circuit 116 so that the stage speed becomes slow. For example, when the stage speed is calculated from information such as frame information and compartment information input from the shot data generation unit 60, a value obtained by multiplying the stage speed information by a coefficient smaller than 1 may be output. In response to the signal, the stage drive control circuit 116 performs drawing while reducing the stage speed.

  As a determination step (S118), the determination unit 74 in the control computer 114 determines whether the drawing processing speed is faster than the plan based on the planned drawing time. If it is fast, the process returns to S116, and the drawing process control unit 72 continues to suspend the drawing process. Alternatively, control is continued so that the stage speed becomes slow. If the drawing processing speed is not faster than the planned drawing time, the process proceeds to S120.

  In the drawing restart processing step (S120), when the drawing processing speed is not faster than the planned drawing time, the drawing processing control unit 72 controls to restart the drawing processing. Alternatively, the stage speed is recovered.

  As a determination step (S122), the drawing management unit 70 determines whether or not the drawing process has ended. If not, the drawing management unit 70 returns to S114, and if it has ended, the flow ends.

  As described above, the drawing processing control unit 72 controls the drawing operation along the planned drawing time. The drawing process control unit 72 is an example of a drawing control unit. In addition, the drawing unit 150 is controlled by the drawing processing control unit 72 so as to perform a drawing operation according to the planned drawing time, and the sample 101 is coated with a resist that changes a pattern dimension according to a standing time after drawing. A pattern is drawn using the electron beam 200.

  Here, during the drawing process, there may be a request for an operation that is not scheduled when calculating the planned drawing time. For example, the drawing process by the user is temporarily interrupted, and the sample to be drawn next is transported. In the drawing apparatus 100, for example, a process of setting two substrates (samples) and transporting the other to the front of the drawing chamber 103 while drawing one may be performed. At that time, since the vibration caused by the conveyance deteriorates the drawing accuracy, the drawing is temporarily stopped when the paper is conveyed. Since the transport time is not included in the above-described planned drawing time, if the transport process enters between the start of the drawing process and the end, the elapsed time after the drawing will be extended, so the dimensional change of the pattern Will be different from the expected amount. Therefore, the carrying process cannot be performed as it is.

  Therefore, in the first embodiment, the conveyance permission time is set. The time and time when the sample to be drawn next may be conveyed is input from the I / F circuit 111, and the planned drawing time calculation unit 52 performs drawing processing on the drawing target sample when calculating the planned drawing time. Include the time when the sample to be drawn is transported temporarily and the transport time.

  FIG. 5 is a flowchart when the mask carrying process in the first embodiment is performed. In FIG. 5, the drawing management unit 70 determines whether or not the mask conveyance permission time is set (S202). If the mask conveyance permission time is not set, the drawing process control unit 72 waits for mask conveyance until the end of drawing even if there is a request for mask conveyance.

  When there is a mask conveyance permission time setting, the drawing management unit 70 determines whether the current time is before or after the mask conveyance permission start time (S204). When the current time is after the mask conveyance permission start time, the drawing process control unit 72 waits for mask conveyance until the end of drawing even if there is a request for mask conveyance.

  If the current time is before the mask conveyance permission start time, the drawing management unit 70 determines whether the current time is the mask conveyance permission start time (S206). If the current time is the mask transfer permission start time, the drawing process control unit 72 temporarily stops the drawing process and performs the transfer process of the mask substrate to be drawn next instead.

  If the current time is not the mask transfer permission start time, the process returns to S206 while waiting for mask transfer.

  As described above, the dimensional accuracy of the pattern can be obtained even if mask transfer processing is performed by including the timing and time to transfer the sample to be drawn next after temporarily stopping the drawing processing for the sample to be drawn in the planned drawing time. Can be maintained.

  In addition, the drawing process control unit 72 does not perform such an operation when there is a request for an operation that is not scheduled when calculating a planned drawing time such as a temporary interruption of the drawing process by a user other than the mask conveyance process. Control is continued so as to continue the drawing operation along the planned drawing time.

  FIG. 6 is a conceptual diagram for explaining a request rejection method according to the first embodiment. FIG. 6A shows a case where a pause request is input from the I / F circuit 111 during the drawing process according to the planned drawing time. In such a case, a pause command is output to the control computer 114, but is rejected by the drawing management unit 70 or the drawing processing control unit 72. Then, the drawing processing control unit 72 continues to perform control so that the drawing operation is continued along the planned drawing time without performing such an operation. FIG. 6B shows a case in which the I / F circuit 111 is rejected at the stage of inputting a temporary stop request. During the drawing process according to the planned drawing time, a plan mode flag is output from the drawing management unit 70 or the drawing process control unit 72, and the I / F circuit 111 outputs the I / F circuit 111 when the flag is output. To prevent input from. For example, when inputting from the touch panel, it is effective not to display the input button or to disable the input button.

  As described above, according to the first embodiment, when calculating the irradiation dose depending on time, the deviation from the actual drawing processing time can be prevented by using the planned drawing time. Therefore, a more accurate pattern can be drawn.

Embodiment 2. FIG.
In the second embodiment, the case of performing electron beam drift correction is also included in the planned drawing time.

  FIG. 7 is a conceptual diagram for explaining a difference in drawing time depending on the presence or absence of drift correction in the second embodiment. When the beam drift correction is performed periodically, the drawing process is temporarily interrupted while the drift correction is performed. Therefore, when the drawing time is predicted, the drawing end time is delayed by the drift correction time (F).

  FIG. 8 is another conceptual diagram for explaining a difference in drawing time depending on the presence or absence of drift correction in the second embodiment. The drift correction includes a drift correction (F) performed periodically at regular intervals and a drift correction (C) performed irregularly. As described above, a plurality of chip patterns may be drawn on one mask. In such a case, there are chip patterns with different drawing conditions. Therefore, the chips having the same drawing condition are collected as one drawing group (drawing G), and drawing is performed for each drawing group. In such a case, it is often required to perform drift correction (C) after drawing a certain drawing group and before drawing the next drawing group. Moreover, the conveyance process (T) demonstrated in Embodiment 1 may be requested | required during drawing.

  FIG. 9 is a conceptual diagram for explaining a drawing pause interval due to drift correction and conveyance processing in the second embodiment. Since the execution time is constant between drift corrections (F) performed periodically, the execution time can be simply predicted. However, since the timing for performing the drift correction (C) performed between the drawing groups differs depending on the formation of the drawing groups, the implementation timing is not regular. Further, the transfer process is not periodic when the transfer permission time is not set as in the first embodiment. In order to accurately predict the drawing time, it is necessary to grasp the generation time of the request event and the processing time thereof.

  FIG. 10 is a conceptual diagram for explaining a drawing pause interval when events such as drift correction and conveyance processing occur simultaneously in the second embodiment. Since the conveyance processing request and the drift correction (C) occur irregularly, there is a possibility that the drift correction (F) performed periodically and the timing thereof overlap each other or overlap each other. In that case, the drawing apparatus designates which has priority. Therefore, in order to accurately predict the drawing time, it is necessary to grasp such priorities.

  Therefore, in the second embodiment, the drift time for performing drift correction by temporarily interrupting the drawing process on the drawing target sample 101 at the drift correction time is included in the planned drawing time.

  FIG. 11 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the second embodiment. 11 is the same as FIG. 1 except that a drawing group end time calculation unit 54 and a drift correction time calculation unit 56 are added to the control computer 110 and a drift correction unit 119 is added.

  Memory 51, 61, 71, control computer 110, 112, 114, I / F circuit 111, drift correction unit 119, stage drive control circuit 116, deflection control circuit 120, and storage devices 140, 142, 144 such as a magnetic disk device Are connected to each other via a bus 118.

  The functions such as the drawing time prediction unit 50, the planned drawing time calculation unit 52, the drawing group end time calculation unit 54, and the drift correction time calculation unit 56 in the control computer 110 may be configured by software such as a program. . Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. The input data necessary for the control computer 110 or the calculated result is stored in the memory 51 each time.

  FIG. 12 is a flowchart showing main steps of the drawing method according to the second embodiment. In FIG. 12, the drawing method according to the second embodiment includes an inter-drawing group time calculating step (S104) and a drift correction time calculating step between the drawing time prediction step (S102) and the planned drawing time calculation unit (S110). 2 is the same as FIG. 2 except that (S106) and the drawing time re-prediction step (S108) are added. Further, contents not specifically described below are the same as those in the first embodiment.

  In the inter-drawing group time calculation step (S104), the drawing group end time calculation unit 54 calculates the drawing end time of each drawing group from the predicted drawing time information.

  As the drift correction time calculation step (S106), the drift correction time calculation unit 56 inputs regular drift correction interval information and priority information, and performs drift correction (C) time and regular drift correction performed between drawing groups according to the priority information. (F) Time is calculated. In this way, the drift correction time calculation unit 56 calculates the drift correction time (C) of the electron beam 200 with an irregular execution interval using the predicted writing time.

  In the drawing time re-prediction step (S108), the drawing time prediction unit 50 re-predicts the drawing time including the calculated drift correction (C) time and the regular drift correction (F) time between the drawing groups.

  Then, as the planned drawing time calculation unit (S110), the planned drawing time calculation unit 52 calculates a planned drawing time longer than the re-predicted drawing prediction time. Therefore, the planned drawing time includes a drift correction time for performing electron beam drift correction at the drift correction time calculated by temporarily stopping the drawing process on the drawing target sample. Further, as described in the first embodiment, when the planned drawing time calculation unit 52 calculates the planned drawing time, the drawing process for the drawing target sample is temporarily suspended and the next drawing sample is transported. And its transport time.

  The subsequent steps are the same as those in the first embodiment. However, when the period for the periodic drift correction (F) and the irregular drift correction (C) has come, the drawing processing control unit 72 temporarily stops the drawing process, and then the drift correction unit 119 drifts. Make corrections. In addition, for the next transport (T) of the drawing target sample, the transport process is performed along the flow described in FIG.

  By calculating the planned drawing time as described above, even if the regular drift correction (F), the irregular drift correction (C), and the next drawing target sample transport (T) are performed, the dimensional change of the pattern Can be as expected. Therefore, even when processing such as drift correction is performed before the drawing is finished, a more accurate pattern can be drawn.

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

50 Drawing time prediction units 51, 61, 71 Memory 52 Planned drawing time calculation unit 54 Drawing group end time calculation unit 56 Drift correction time calculation unit 60 Shot data generation unit 62 Determination unit 64 Command instruction unit 70 Drawing management unit 72 Drawing process control Unit 74 determination unit 76 irradiation amount calculation unit 100 drawing device 101 sample 102 electron column 103 drawing room 105 XY stages 110, 112, 114 control computer 111 I / F circuit 116 stage drive control circuit 119 drift correction unit 120 deflection control circuit 130 DAC amplifier units 140, 142, 144 Storage device 150 Drawing unit 160 Control unit 200 Electron beam 201 Electron gun 202 Illumination lens 203 First shaping aperture 204 Projection lens 205 Deflector 206 Second shaping aperture 207 Objective lens 208 Deflector 2 2 blanking deflector 214 the blanking aperture 330 electron beam 340 Sample 410 first aperture 411 opening 420 second aperture 421 variable-shaped opening 430 a charged particle source

Claims (5)

A planned drawing time calculation unit for calculating a planned drawing time longer than the predicted drawing predicted time;
A drawing control unit for controlling a drawing operation along the planned drawing time;
A pattern is formed using a charged particle beam on a sample coated with a resist that changes the pattern size according to the standing time after drawing while being controlled by the drawing control unit to perform the drawing operation along the planned drawing time. A drawing section for drawing;
A charged particle beam drawing apparatus comprising:   The drawing control unit controls to continue the drawing operation along the planned drawing time without performing the operation when there is a request for an operation that is not scheduled when calculating the planned drawing time. The charged particle beam drawing apparatus according to claim 1, which is continued.   3. The plan drawing time calculation unit includes the transport time for transporting a sample to be drawn next after the drawing process for the sample to be drawn is temporarily suspended in the planned drawing time. 4. Charged particle beam lithography system. A drawing time prediction unit for calculating the drawing prediction time;
A drift correction time calculation unit for calculating a drift correction time of a charged particle beam having an irregular execution interval using the drawing prediction time;
Further comprising
The planned drawing time calculation unit includes, in the planned drawing time, a drift correction time for performing drift correction of a charged particle beam at a drift correction time calculated by temporarily interrupting a drawing process on a drawing target sample. The charged particle beam drawing apparatus according to claim 1. Calculating a planned drawing time longer than the predicted drawing prediction time;
A step of drawing a pattern using a charged particle beam on a sample coated with a resist that changes a pattern size according to a standing time after drawing while controlling the drawing operation to be performed along the planned drawing time; ,
A charged particle beam drawing method comprising:

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