JP6063767B2 - Failure diagnosis method for electron beam drawing apparatus, electron beam drawing apparatus - Google Patents

Description

  Embodiments described herein relate generally to an electron beam drawing apparatus failure diagnosis method and an electron beam drawing apparatus for drawing a mask substrate with an electron beam.

  An electron beam drawing apparatus is used to create a mask substrate used for manufacturing a semiconductor device. In the electron beam drawing apparatus, a pattern is drawn by irradiating a mask substrate with an electron beam and exposing a resist applied to the mask substrate. The quality determination of the drawn pattern (drawing pattern) is usually performed after resist development, so that if there is a defect in the drawing pattern, the pattern is drawn again on the mask substrate.

  However, in recent years, semiconductor devices have been miniaturized, and patterns drawn on a mask substrate have also been miniaturized. For this reason, the time required for drawing on the mask substrate is increased. For example, depending on the drawing pattern, it may take ten or more hours to draw one mask substrate. For this reason, if a defect is found in the drawing pattern after development, a huge amount of time is wasted.

  Therefore, in the conventional electron beam drawing apparatus, failure diagnosis of the electron beam drawing apparatus (for example, a register, an arithmetic element, a circuit, or the like constituting the electron beam drawing apparatus) is performed, and a defect in the drawing pattern by the electron beam drawing apparatus is obviated. I try to prevent it. However, in the conventional electron beam drawing apparatus, the mask substrate cannot be drawn during the failure diagnosis of the electron beam drawing apparatus. Therefore, the time required for the failure diagnosis of the electron beam drawing apparatus remains as it is as the downtime of the electron beam drawing apparatus. It has become.

  At present, as the pattern drawn on the mask substrate is miniaturized, the electron beam drawing apparatus has also been improved in performance, and the time required for failure diagnosis has increased (for example, a failure for 5 minutes at a time). Even if the diagnosis is performed twice a day, 2.5 days will be used for fault diagnosis in one year). For this reason, the time of downtime is also increasing. Therefore, some conventional electron beam lithography systems reduce the downtime of the electron beam lithography system by diagnosing the failure of the electron beam lithography system during evacuation of the load lock or during transfer of the mask substrate. (See Patent Document 1).

Japanese Patent No. 3291591

  As described above, reduction of downtime by failure diagnosis of an electron beam drawing apparatus has been conventionally demanded. An object of the present embodiment is to provide an electron beam drawing apparatus failure diagnosis method and an electron beam drawing apparatus that can reduce downtime due to failure diagnosis.

A failure diagnosis method for an electron beam lithography apparatus according to an embodiment of the present invention is a failure diagnosis method for an electron beam lithography apparatus that draws a desired pattern on a mask substrate using an electron beam, and is used for calibration provided on the stage. Irradiating the mark with the electron beam to acquire calibration data, and diagnosing the presence or absence of a self failure while acquiring the calibration data .

The schematic diagram which shows the structure of the electron beam drawing apparatus which concerns on embodiment. The schematic diagram which shows the structure of the electronic lens-barrel and control mechanism which concern on embodiment. 6 is a flowchart showing an operation (when deployed) of the electron beam drawing apparatus according to the embodiment. 6 is a flowchart showing an operation (during drawing) of the electron beam drawing apparatus according to the embodiment. 6 is a flowchart showing an operation (at the time of obtaining calibration parameters) of the electron beam drawing apparatus according to the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment)
FIG. 1 is a schematic view (partially sectional view) of an electron beam lithography apparatus 10 according to the embodiment. FIG. 2 is a schematic diagram showing the configuration of the electron column 500 and the control mechanism 600. Hereinafter, the configuration of the electron beam drawing apparatus 10 will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the electron beam drawing apparatus 10 includes an interface (I / F) 100, a carry-in / out (I / O) chamber 200, a robot chamber (R chamber) 300, and a writing chamber (W chamber) 400. And an electron column 500, a control mechanism 600, and gate valves G1 to G3.

  The I / F 100 includes a mounting table 110 on which a container C (for example, SMIFPod) containing a mask substrate W used in this embodiment is mounted, and a transport robot 120 that transports the mask substrate W. The mask substrate W is a quartz substrate or the like with a light shielding film formed on the surface, and a resist is coated on the light shielding film.

  The I / O chamber 200 is a load lock chamber for carrying in and out the mask substrate W while keeping the inside of the R chamber 300 in a vacuum (low atmospheric pressure). The I / O chamber 200 is provided with a gate valve G1 between the I / O chamber 200 and a vacuum pump (not shown) and a gas supply system. The vacuum pump is, for example, a dry pump or a turbo molecular pump, and evacuates the I / O chamber 200. The gas supply system supplies venting gas (for example, nitrogen gas or CDA (Clean Dry Gas)) into the I / O chamber 200 when the I / O chamber 200 is at atmospheric pressure.

  When the inside of the I / O chamber 200 is evacuated, it is evacuated using a vacuum pump connected to the I / O chamber 200. Further, when the inside of the I / O chamber 200 is returned to the atmospheric pressure, vent gas is supplied from the gas supply system, and the inside of the I / O chamber 200 becomes the atmospheric pressure. Note that when the inside of the I / O chamber 200 is evacuated and at atmospheric pressure, the gate valves G1 and G2 are closed.

  The R chamber 300 includes a transfer robot 310 for the mask substrate W. The R chamber 300 is connected to the I / O chamber 200 via the gate valve G2. The transfer robot 310 transfers the mask substrate W between the I / O chamber 200 and the W chamber 400. Although not shown, the R chamber 300 includes an alignment chamber for positioning (aligning) the mask substrate W, a housing chamber for housing the substrate cover H placed on the mask substrate W, and the R chamber 300 in a vacuum. A vacuum pump (for example, a Cryo pump or a turbo molecular pump) is provided.

  The W chamber 400 includes a stage 410, a drive mechanism 420, a laser length measuring system 430, and a vacuum pump (not shown) (for example, a Cryo pump or a turbo molecular pump), and is connected to the R chamber 300 via a gate valve G3. ing.

  The stage 410 is a table for placing the mask substrate W, and the mask substrate W is placed on the stage 410 by the transfer robot 310 of the R chamber 300. On the stage 410, a reflecting mirror (mirror) M used for measuring the position of the stage 410 and an alignment mark AM (for example, a Faraday cup) used for calibration of the irradiation amount and irradiation position of the electron beam B are provided. Yes.

  A drive mechanism 420 (for example, a motor) drives the stage 410. Laser length measurement system 430 is an interferometer for detecting the position of stage 410. The laser measurement system 430 receives the reflected light by irradiating the reflecting mirror M provided on the stage 410 with a laser, and calculates the distance from the reflecting mirror M from the interference between the irradiated light and the reflected light.

  Although not shown, the W chamber 400 includes a vacuum pump (for example, a Cryo pump or a turbo molecular pump) for evacuating the W chamber 400. The inside of the W chamber 400 is evacuated by this vacuum pump and maintained at a pressure at which electronic drawing is possible.

  The electron column 500 includes an electron gun 510, deflectors 511 to 513, electrostatic lenses 521 to 523, and apertures 531 and 532. The electron gun 510 irradiates the electron beam B. The deflectors 511 to 513 deflect the electron beam B. The electrostatic lenses 521 to 523 adjust the focus and astigmatism of the electron beam B. The apertures 531 and 532 are aperture plates for controlling the shape and size of the electron beam B and ON / OFF.

  The position, focus, astigmatism, shape, size, etc. of the electron beam B emitted from the electron gun 510 are adjusted on the stage 410 by the deflectors 511 to 513, the electrostatic lenses 521 to 523 and the apertures 531 and 532. Irradiation is performed on the placed mask substrate W.

(Configuration of control mechanism 600)
The control mechanism 600 includes a developing unit 610, a drawing control unit 620, a deflection unit 630, and a stage control unit 640. Each component of the control mechanism 600 includes a processor, a memory, and the like.

  The developing unit 610, the deflecting unit 630, and the stage control unit 640 are configured to perform a normal operation (drawing mode) and a mode for performing self-fault diagnosis (diagnostic mode) according to an instruction from the drawing control unit 620. ) And switch. Each of the developing unit 610, the deflecting unit 630, and the stage control unit 640 is provided with a mode setting register. Normally, the registers are set so that the drawing mode has priority. Hereinafter, each configuration will be described for each mode.

(Drawing mode)
The expansion unit 610 expands (converts) data describing a drawing pattern on the mask substrate (hereinafter referred to as pattern data) into drawing data (language) understandable by the electron beam drawing apparatus 10. The pattern data is described in CAD, for example.

  Specifically, the development unit 610 divides the pattern data into a large number of areas, and includes the electron beam shot size, shape, dose, position, etc. necessary for drawing the pattern drawn in each area. Convert to drawing data. The development unit 610 sequentially outputs the rendered drawing data for each predetermined unit (for example, divided areas).

  The drawing control unit 620 controls the development of the pattern data to the development unit 610 and the transfer of the drawing data after the development. Further, the drawing control unit 620 controls the start and stop of the failure diagnosis operation of the development unit 610, the deflection unit 630, and the stage control unit 640.

  The deflecting unit 630 controls the deflectors 511 to 513 based on the drawing data transferred from the developing unit 610 to adjust the irradiation position, shape, and the like of the electron beam B. Signals from the deflecting unit 630 are amplified by amplifiers AMP-1 to AMP-3 and then applied to the deflectors 511 to 513, respectively. Further, the deflection unit 630 controls the stage control unit 640 based on the drawing data transferred from the development unit 610.

  The stage controller 640 detects the position of the stage 410 in real time based on distance information from the laser length measurement system 430. Further, the stage control unit 640 controls the drive mechanism 420 based on an instruction from the deflection unit 630 to drive the stage 410.

(Diagnostic mode)
The development unit 610, the deflection unit 630, and the stage control unit 640 diagnose the presence or absence of their own failure based on an instruction from the drawing control unit 620. A failure diagnosis program is stored in each memory of the expansion unit 610, the deflection unit 630, and the stage control unit 640. By executing this failure diagnosis program, the expansion unit 610, the deflection unit 630, and the stage control unit 640 Diagnose the presence of self-failure.

  The failure diagnosis includes a communication error (for example, a communication error during optical communication), a memory read / write (Read / Write) error, a calculation error (register error), a memory free capacity diagnosis, and the like. The memory includes a drawing data buffer memory, a memory for storing calibration parameters (calibration data), a debugging memory, and the like. The failure diagnosis is performed using a checksum, a cyclic redundancy check (CRC), or the like.

(Operation of the electron beam drawing apparatus 10)
3 to 5 are flowcharts showing operations at the time of failure diagnosis of the electron beam drawing apparatus 10. Hereinafter, the operation at the time of failure diagnosis of the electron beam drawing apparatus 10 will be described with reference to FIGS.

(Failure diagnosis operation during pattern data development)
First, with reference to FIGS. 1 to 3, an operation at the time of failure diagnosis of the electron beam drawing apparatus 10 during pattern data development will be described. In this failure diagnosis, the failure diagnosis of the deflection unit 630 and the stage control unit 640 that are not used is performed while the development unit 610 is developing the pattern data, thereby effectively reducing the downtime due to the failure diagnosis.

  When the drawing operation of the electron beam drawing apparatus 10 is started, the drawing control unit 620 instructs the developing unit 610 to develop pattern data into drawing data (step S101). Next, the drawing control unit 620 instructs the deflection unit 630 and the stage control unit 640 to start its own failure diagnosis (step S102). In response to the instruction, the deflection unit 630 and the stage control unit 640 are switched from the drawing mode to the diagnosis mode.

  The development unit 610 starts development of pattern data into drawing data in response to an instruction from the drawing control unit 620 (step S103). The deflection unit 630 and the stage control unit 640 start failure diagnosis of the deflection unit 630 and the stage control unit 640 according to an instruction from the drawing control unit 620 (step S104).

  The expansion unit 610 expands the pattern data, and when a predetermined unit is reached, transmits a transfer preparation completion report indicating that preparation for transferring the developed drawing data is completed to the drawing control unit 620 (step S105). Upon receiving the transfer preparation completion report from the development unit 610, the drawing control unit 620 instructs the deflection unit 630 and the stage control unit 640 to interrupt the fault diagnosis (step S106).

  The deflecting unit 630 and the stage control unit 640 stop their own fault diagnosis, and store in the memory the items for which the fault diagnosis has been completed (how far the fault diagnosis has been completed) and the fault diagnosis result (step S107). Next, the deflection unit 630 and the stage control unit 640 transfer the result of the failure diagnosis to the drawing control unit 620 (step S108).

  The drawing control unit 620 checks whether there is an abnormality in the failure diagnosis result (step S109). If there is an abnormality in the failure diagnosis result (YES in step S109), the drawing control unit 620 executes a process corresponding to the abnormality, such as stopping drawing (step S110). If there is no abnormality in the failure diagnosis result (NO in step S109), the drawing control unit 620 instructs the developing unit 610 to transfer the drawing data (step S111). In addition, the drawing control unit 620 instructs the deflection unit 630 and the stage control unit 640 to start drawing control (step S112). After the instruction, the deflection unit 630 and the stage control unit 640 switch from the diagnosis mode to the drawing mode.

  The developing unit 610 transfers the drawing data developed in accordance with an instruction from the drawing control unit 620 (step S113). The deflection unit 630 and the stage control unit 640 continue the drawing process based on the drawing data transferred from the developing unit 610 (step S114). The developing unit 610 starts developing the next pattern data after transferring the drawing data.

  As described above, while the pattern data is developed by the development unit 610, failure diagnosis of the deflection unit 630 and the stage control unit 640 that are not used is performed. For this reason, the downtime by failure diagnosis can be reduced effectively. In addition, when the failure diagnosis is stopped, how far the failure diagnosis has been completed is stored, so that the failure diagnosis can be continued from the next failure diagnosis. For this reason, it is not necessary to restart the failure diagnosis from the beginning each time the failure diagnosis is interrupted. As a result, downtime due to failure diagnosis can be reduced more effectively.

(Failure diagnosis operation during drawing)
Next, with reference to FIG. 1, FIG. 2, and FIG. 4, the operation at the time of failure diagnosis of the electron beam drawing apparatus 10 during drawing will be described. In this failure diagnosis, the failure of the developing unit 610 and the deflecting unit 630 that are not used until the next drawing area enters the electron beam irradiation region (deflection region) after drawing of an arbitrary area is completed. Diagnosing effectively reduces downtime due to failure diagnosis.

  When the drawing operation in the predetermined area is completed (step S201), the drawing control unit 620 instructs the developing unit 610 and the deflecting unit 630 to start own fault diagnosis (step S202). In response to the instruction, the developing unit 610 and the deflecting unit 630 are switched from the drawing mode to the diagnostic mode. The stage control unit 640 moves the stage 410 until the next drawing area enters the electron beam irradiation area (deflection area) (step S203).

  The developing unit 610 and the deflecting unit 630 start their own fault diagnosis in response to an instruction from the drawing control unit 620 (step S204). When the stage 410 moves until the next drawing area enters the electron beam irradiation area (deflection area), the stage control section 640 sends a movement completion report indicating that the movement of the stage 410 is completed. (Step S204).

  When the drawing control unit 620 receives the movement completion report from the stage control unit 640, the drawing control unit 620 instructs the development unit 610 and the deflection unit 630 to interrupt the failure diagnosis (step S205). The developing unit 610 and the deflecting unit 630 stop the failure diagnosis, and store the items for which the failure diagnosis has been completed (how far the failure diagnosis has been completed) and the failure diagnosis result in the memory (step S206). Next, the developing unit 610 and the deflecting unit 630 transfer the result of failure diagnosis to the drawing control unit 620 (step S207).

  The drawing control unit 620 checks whether there is an abnormality in the failure diagnosis result (step S208). If there is an abnormality in the failure diagnosis result (YES in step S208), the drawing control unit 620 executes processing corresponding to the abnormality, such as stopping drawing (step S209). If there is no abnormality in the failure diagnosis result (NO in step S208), the drawing control unit 620 instructs the developing unit 610 and the deflecting unit 630 to continue the drawing operation (step S210). In response to the instruction, the developing unit 610 and the deflecting unit 630 are switched from the diagnostic mode to the drawing mode.

  As described above, after the drawing of an arbitrary area is completed, the developing unit 610 and the deflecting unit 630 that are not used are broken until the next drawing area enters the electron beam irradiation region (deflection region). I have a diagnosis. For this reason, the downtime by failure diagnosis can be reduced effectively. In addition, when the failure diagnosis is stopped, how far the failure diagnosis has been completed is stored, so that the failure diagnosis can be continued from the next failure diagnosis. For this reason, it is not necessary to restart the failure diagnosis from the beginning each time the failure diagnosis is interrupted. As a result, downtime due to failure diagnosis can be reduced more effectively.

(Failure diagnosis operation during acquisition of calibration parameters)
Next, the operation at the time of failure diagnosis of the electron beam drawing apparatus 10 that is acquiring the calibration parameters will be described with reference to FIGS. In this failure diagnosis, while the deflection unit 630 and the stage control unit 640 are used to acquire the calibration parameters, the failure diagnosis of the deployment unit 610 that is not used is performed, thereby reducing the downtime due to the failure diagnosis. Has been reduced.

  In the electron beam drawing apparatus 10, the irradiation mark and irradiation position of the electron beam B are calibrated periodically using the alignment mark AM. For this reason, downtime due to failure diagnosis can be greatly reduced by performing failure diagnosis of the developing unit 610 that is not used when acquiring the calibration parameters.

  The drawing control unit 620 instructs the deflection unit 630 and the stage control unit 640 to acquire calibration parameters (step S301). The deflection unit 630 and the stage control unit 640 start to acquire the calibration parameters using the alignment marks AM provided on the stage 410 in order to update the calibration parameters stored in the memory (step S302).

  The drawing control unit 620 instructs the development unit 610 to perform its own fault diagnosis (step S303). In response to the instruction, the expansion unit 610 switches from the drawing mode to the diagnostic mode. The unfolding unit 610 starts its own failure diagnosis according to an instruction from the drawing control unit 620 (step S304).

  When the acquisition of the calibration parameter is completed, the deflection unit 630 and the stage control unit 640 transmit an acquisition completion report indicating that the acquisition of the calibration parameter is completed to the drawing control unit 620 (step S305). Upon receiving the acquisition completion report, the drawing control unit 620 instructs the development unit 610 to interrupt the fault diagnosis (step S306).

  The expansion unit 610 stops the failure diagnosis, and stores in the memory the item for which the failure diagnosis has been completed (how far the failure diagnosis has been completed) and the failure diagnosis result (step S307). Next, the expansion unit 610 transfers the failure diagnosis result to the drawing control unit 620 (step S308).

  The drawing control unit 620 checks whether there is an abnormality in the failure diagnosis result (step S309). If there is an abnormality in the failure diagnosis result (YES in step S309), the drawing control unit 620 executes processing corresponding to the abnormality, such as stopping drawing (step S310). If there is no abnormality in the failure diagnosis result (NO in step S309), the drawing control unit 620 instructs the developing unit 610 to continue the drawing operation as it is (step S310). After the instruction, the development unit 610 switches from the diagnosis mode to the drawing mode.

  As described above, while the deflection unit 630 and the stage control unit 640 are used to acquire the calibration parameters, the failure diagnosis of the developing unit 610 that is not used is performed. For this reason, the downtime by failure diagnosis can be reduced effectively. In addition, when the failure diagnosis is stopped, how far the failure diagnosis has been completed is stored, so that the failure diagnosis can be continued from the next failure diagnosis. For this reason, it is not necessary to restart the failure diagnosis from the beginning each time the failure diagnosis is interrupted. As a result, downtime due to failure diagnosis can be reduced more effectively.

(Other embodiments)
In addition, although some embodiment of this invention was described, the said embodiment is an illustration and does not intend limiting this invention to the said embodiment. The above embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. For example, in the above embodiment, failure diagnosis of a memory that backs up drawing data during drawing may be performed.

  DESCRIPTION OF SYMBOLS 10 ... Electron beam drawing apparatus, 110 ... Mounting table, 120 ... Transfer robot, 200 ... I / O chamber, 300 ... R chamber, 310 ... Transfer robot, 400 ... W chamber, 410 ... Stage, 420 ... Drive mechanism, 430 ... Laser length measuring system, 500 ... electron barrel, 510 ... electron gun, 511-513 ... deflector, 521-523 ... electrostatic lens, 531, 532 ... aperture, 600 ... control mechanism, 610 ... deployment unit, 620 ... drawing Control unit, 630... Deflection unit, 640... Stage control unit.

Claims (2)

A failure diagnosis method for an electron beam drawing apparatus for drawing a desired pattern on a mask substrate placed on a stage by an electron beam,
Irradiating the calibration mark provided on the stage with the electron beam to obtain calibration data;
Diagnosing the presence or absence of a self failure while acquiring the calibration data;
A fault diagnosis method for an electron beam lithography apparatus having An electronic beam drawing apparatus for drawing a desired pattern by the Lima disk substrate to an electron beam,
A calibration mark is provided, and a stage on which the mask substrate is placed;
And a deflection unit for deflecting the previous Symbol electron beam,
And a stage control unit for driving the previous Symbol stage,
A development unit that develops pattern data of the pattern into drawing data, and performs self-failure diagnosis;
Instructing the deflection unit and the stage control unit to acquire calibration data by irradiating the calibration mark with the electron beam, and performing failure diagnosis on the developing unit while acquiring the calibration data A control unit for instructing
Bei obtain an electron beam lithography apparatus.

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