JP6214441B2 - Deflector cleaning device and deflector cleaning method - Google Patents

Description

  The present invention relates to a deflector cleaning device and a deflector cleaning method.

  An electron beam drawing apparatus for drawing a desired pattern on a sample such as a mask substrate has a deflector in order to control the irradiation position of the electron beam on the sample. A sample is placed immediately below the deflector. When particles are attached to the deflector, the particles are peeled off from the deflector to contaminate the sample. In order to suppress such contamination of the sample, the deflector needs to be cleaned cleanly.

  Conventionally, cleaning of the deflector has been performed manually using an ionizer. Therefore, the cleaning quality varies.

JP 2002-93696 A

  An object of one embodiment of the present invention is to provide a deflector cleaning apparatus and a deflector cleaning method capable of achieving uniform cleaning quality.

A deflector cleaning device according to an aspect of the present invention is a deflector cleaning device that cleans a deflector used in a charged beam drawing apparatus, and includes a chamber, a support on which the deflector is placed in the chamber, and a support A moving mechanism for rotating the support and moving the support in the vertical direction, an ionizer having a plurality of nozzles for ejecting ionized gas into the chamber, and a down flow into the chamber An airflow control mechanism for generating a gas, and a particle detection device disposed above the moving mechanism and below the deflector in the chamber. The first nozzle that ejects the ionized gas and ionization in the horizontal direction from the side of the chamber Having a second nozzle unit, and a third nozzle for injecting ionized gas obliquely upwardly from the side of the chamber, a for jetting the gas.

  In the cleaning device for a deflector according to one aspect of the present invention, the plurality of nozzle portions from which the ionized gas is ejected is selected so that the ionized gas is not ejected from at least the plurality of nozzle portions adjacent to each other. It has a control part.

  In the deflector cleaning device according to one embodiment of the present invention, the chamber has a shape in which at least the upper diameter is larger than the lower diameter.

  In the deflector cleaning device according to one aspect of the present invention, the airflow control mechanism controls the wind speed so that the downflow wind speed in the chamber is constant.

A deflector cleaning method according to an aspect of the present invention is a deflector cleaning method for cleaning a deflector used in a charged beam lithography apparatus, and the deflector is attached to a support body installed in a chamber. The ionized gas is placed on the upper surface, the side surface, and the lower surface of the deflector while the deflector is moved in the chamber by placing and rotating the support and moving the support in the vertical direction. Particles ejected and adhered to the deflector are peeled off, a down flow is generated in the chamber, the peeled particles are moved downward, the particles are detected under the deflector, and the cleaning of the deflector is completed. This is a method for determining whether or not.

  According to the deflector cleaning device and the deflector cleaning method of the present invention, the cleaning quality can be made uniform.

It is a figure which shows typically the cleaning apparatus for deflectors which concerns on one embodiment of this invention. It is a figure which expands and shows the deflector arrange | positioned on the some support | pillar and its periphery. It is an electric block diagram which shows the cleaning apparatus for deflectors which concerns on one embodiment of this invention. It is a flowchart which shows the cleaning method of the deflector which concerns on one embodiment of this invention.

  A deflector cleaning device and a deflector cleaning method according to one embodiment of the present invention will be described below.

  FIG. 1 is a diagram schematically showing a deflector cleaning device according to an embodiment of the present invention. A deflector cleaning apparatus 10 shown in FIG. 1 uses, for example, a deflector 11 used in a charged beam drawing apparatus as an object to be cleaned, and jets ionized gas onto the surface of the deflector 11 at a predetermined pressure / flow rate. The particles adhering to the deflector 11 are peeled off to clean the deflector 11.

  The deflector cleaning device 10 is loaded with a deflector 11 to be cleaned and is cleaned. An ionizer 13 for ejecting a gas ionized in the deflector 11 in the chamber 12 at a predetermined wind speed. 12 includes an airflow control mechanism 14 that generates a downflow, and a particle detection device 15 that detects particles peeled off from the deflector 11.

  The chamber 12 is made of, for example, stainless steel (SUS) or the like and is supported by the gantry 16. The chamber 12 is a portion below the broken line AA ′ in FIG. 1 and has a chamber main body 12a provided with an opening at the top, and a lid provided above the chamber main body 12a and provided to cover the opening. It is comprised from the body 12b. The lid 12b can open and close the opening of the chamber body 12a by sliding in the horizontal direction, for example. A handle 17 for moving the lid 12b relative to the chamber body 12a is provided on the side surface of the lid 12b. By providing the handle 17 on the side surface of the lid 12b, it is possible to prevent the particles from falling by passing over the chamber body 12a whose arms and the like are opened when the lid 12b is moved.

  Such a chamber 12 corresponds to the shape of the deflector 11 arranged inside, and has such a shape that the downflow inside the chamber 12 flows smoothly without being disturbed. For example, when the deflector 11 is substantially T-shaped as illustrated, at least the diameter of the upper portion of the chamber body 12a is substantially tapered so as to correspond to this shape.

  Inside the chamber 12, there are provided a plurality of support columns 19 that are supports for supporting the deflector 11, and a moving mechanism 18 that moves the deflector 11.

  FIG. 2 is an enlarged view showing the deflector 11 placed on the plurality of support columns 19 and the periphery thereof. As shown in FIG. 2, the deflector 11 is fixed to the ring-shaped adapter 20 with, for example, screws 21. Then, the deflector 11 is placed on the upper ends of the plurality of columns 19 via the adapter 20. In this way, the deflector 11 is supported by the plurality of support columns 19. The adapter 20 is provided with a plurality of through holes 22. Each of these through holes 22 is a ventilation hole.

  By preparing such an adapter 20 for each shape of the deflector 11, the plurality of support columns 19 can support the deflectors 11 having various shapes.

  When the deflector 11 is fixed to the adapter 20, the ionized gas cannot be supplied to the contact surface S that is a surface in contact with the adapter 20 of the deflector 11, and the surface S is cleaned. I can't. However, when the deflector 11 is attached to the charged beam drawing apparatus, the outer peripheral portion P of the deflector 11 does not enter the vacuum chamber of the charged beam drawing apparatus but is exposed to the outside air. Therefore, the outer peripheral portion P is a region where there is no influence in the vacuum chamber even if particles are attached. The deflector 11 is fixed to the adapter 20 by contacting the adapter 20 in the region P.

  The moving mechanism 18 inside the chamber 12 rotates the plurality of support columns 19 and moves the deflectors 11 supported by the plurality of support columns 19 in the vertical direction by moving the support columns 19 in the vertical direction. In the present embodiment, the moving mechanism 18 rotates the plurality of support columns 19 stepwise and moves them stepwise in the vertical direction.

  The ionizer 13 peels off particles adhering to the deflector 11 by ejecting ionized gas such as ionized compressed air at a predetermined wind speed onto the deflector 11 supported by the support column 19. .

  The ionizer 13 includes, for example, a dryer that removes moisture in the air, a filter regulator that controls the compressed air to a desired pressure, a needle valve that controls the flow rate, a flow meter that measures the flow rate, plus (+) minus (− ) Gas control box 13a including an ionizer controller for controlling the generation of ions, a solenoid valve for selecting a flow path (nozzle part) of compressed air, a sequencer for controlling ON / OFF of ionization, and the like from the gas control box 13a to one end thereof A plurality of pipes 13b to which compressed air is supplied and a nozzle portion 13c connected to the other end of each pipe 13b and ionizing and discharging the compressed air flowing through each pipe 13b are provided.

  The gas control box 13a is disposed, for example, inside or above the gantry 16 and is controlled by a PC (control unit) 31 described later.

  The nozzle portion 13c is provided with an ionization mechanism (not shown) that decomposes air into plus (+) ions and minus (−) ions, such as a discharge mechanism, at the tip thereof, and is supplied from the pipe 13b. The compressed air is ionized and ejected at a predetermined wind speed. The plurality of nozzle portions 13c deflect the ionized compressed air ejected from them over the entire surface of the deflector 11 that moves up and down at a substantially uniform wind speed. 11 is installed on the side surface of the chamber 12.

  Among the plurality of nozzle portions 13c, each of the plurality of first nozzle portions 13c-1 installed above the deflector 11 ejects compressed air ionized mainly on the upper surface of the deflector 11. Each of the plurality of first nozzle portions 13 c-1 ejects compressed air ionized from a direction substantially perpendicular to the upper surface of the deflector 11 above the deflector 11 inside the chamber 12. It is installed so that it can. The plurality of first nozzle portions 13c-1 are arranged in a line at a predetermined pitch (for example, 30 mm pitch).

  It should be noted that some of the first nozzle portions 13c-1 may be installed so that compressed air ionized from an oblique direction with respect to the upper surface of the deflector 11 can be ejected.

  Of the plurality of nozzle portions 13 c, each of the plurality of second nozzle portions 13 c-2 provided on the side surface of the chamber 12 ejects compressed air ionized mainly on the side surface of the deflector 11. Each of the plurality of second nozzle portions 13c-2 is installed on the side surface of the chamber 12 so that compressed air ionized in a direction substantially perpendicular to the side surface of the chamber 12 can be ejected. . The plurality of second nozzle portions 13c-2 are arranged in a line from above to below at a predetermined pitch (for example, 30 mm pitch).

  Of the plurality of nozzle portions 13 c, each of the plurality of third nozzle portions 13 c-3 provided on the side surface of the chamber 12 ejects compressed air that is ionized mainly on the lower surface of the deflector 11. Each of the plurality of third nozzle portions 13c-3 is installed on the side surface of the chamber 12 so as to eject compressed air ionized obliquely upward with respect to the side surface of the chamber 12. . The plurality of third nozzle portions 13c-3 are arranged in a line at a predetermined pitch (for example, 30 mm pitch).

  In the present embodiment, the first nozzle portion 13c-1 has six locations, the second nozzle portion 13c-2 has seven locations, and the third nozzle portion 13c-3 has five locations. Although the nozzle part 13c is installed in 18 places, an installation position and a number are not limited and can be provided suitably.

  The plurality of nozzle portions 13c are preferably switched ON / OFF by an electromagnetic valve or the like as appropriate so that at least adjacent nozzle portions 13c do not simultaneously eject ionized compressed air. It can suppress that the ions ejected from the adjacent nozzle part 13c cancel each other.

  In this embodiment, the ionizer 13 may decompose the compressed air into plus (+) ions and minus (−) ions, and eject them in an equal amount to each other. Negative (-) ions may be ejected separately. Further, the amount of plus (+) ions and the amount of minus (−) ions do not have to be equal to each other, and the gas to be each ion is not limited to air, but includes a very small amount of water.

  The chamber 12 is provided with an airflow control mechanism 14 that generates a downflow in the chamber 12. The downflow generated by the airflow control mechanism 14 moves the particles peeled off from the deflector 11 by the ionizer 13 at least from the deflector 11 downward.

  The airflow control mechanism 14 includes a fan 14a that takes in air from the outside of the chamber 12 at a fixed flow rate that is arbitrarily determined, and a blower 14b that discharges air inside the chamber 12 to the outside.

  The fan 14 a is provided at the upper end of the chamber 12 via a filter 23. When the fan 14 a takes in air from the outside of the chamber 12, the taken-in air is supplied into the chamber 12 through the filter 23. The supplied air is clean air because particles are collected by the filter 23.

  As the filter 23, it is preferable to use an ULPA filter which is an ultra-high performance filter capable of collecting 99.9995% of 0.15 μm particles.

  The blower 14b is provided in the lower part of the chamber 12, for example, the blower control part 26 electrically controls the rotation speed of the blower 14b, thereby adjusting the amount of air discharged from the discharge flow rate chamber 12. By such electrical control, the wind speed in the chamber 12 has changed due to fluctuations in the number of jets due to switching of the nozzle portion 13c from which ionized compressed air is jetted and fluctuations in the jet flow rate of ionized compressed air. In some cases, the flow rate of the air discharged by the blower 14b can be automatically adjusted (selected), and a constant downflow velocity can be generated in the chamber 12 so that air current is not disturbed. The blower 14b discharges the air in the chamber 12 from the exhaust port 25 at the flow rate controlled in this way. The discharge flow rate may be manually adjusted by a manual butterfly valve 24 provided at the upper portion of the blower 14b.

  Further, in the chamber 12, a particle detection device 15 is provided below the lower end of the deflector 11 to be cleaned and above the moving mechanism 18. Examples of the particle detection device 15 include a particle counter 15 a that can detect the amount and size of particles peeled off from the deflector 11 by the ionizer 13. By detecting the amount of particles peeled off from the deflector 11, the particle counter 15a can confirm whether or not the cleaning of the deflector 11 has been completed. For example, when the amount of particles detected by the particle counter 15a becomes 0, it can be confirmed that the cleaning of the deflector 11 has been completed.

  Furthermore, a particle collecting device 15b may be provided to collect particles that have been peeled off from the deflector 11. By analyzing the collected particles, the source of the particles can be specified. The particle counter 15a and the particle collecting device 15b can be appropriately moved in the horizontal direction by the particle counter controller 27, and can detect particles near or in the center of the side surface of the chamber body 12a.

  In the chamber 12, an anemometer 28 that can detect the wind speed in the chamber 12 may be provided below the deflector 11 and above the moving mechanism 18. Similarly to the particle counter 15a and the like, the anemometer 28 can be moved horizontally in the chamber 12 by the anemometer controller 29.

  In addition, a rack 32 on which various power sources 30 and a PC (control unit) 31 are mounted is disposed in the vicinity of the gantry 16 that supports the chamber 12 and includes the gas control box 13a and the like. As shown in the electrical block diagram of the deflector cleaning apparatus 10 according to the embodiment in FIG. 3, the PC 31 includes a moving mechanism 18, a gas control box 13a, a blower control unit 26, a particle counter controller 27, an anemometer controller 29, and the like. A series of cleaning operations by the ionizer 12 including selection of a nozzle unit to which connected and ionized compressed air is ejected, movement of the deflector 11, and downflow by the airflow control mechanism 14 are controlled.

  A cleaning program (recipe) for cleaning the deflector 11 is stored in the PC (control unit) 31 in advance, and the deflector cleaning device 10 can be operated according to this program. For example, a plurality of different cleaning programs (recipes) are stored in the PC (control unit) 31 and the user selects and executes one of the plurality of programs according to the type or history of the deflector 11. Accordingly, the deflector cleaning device 10 can be optimally operated.

  Hereinafter, a method of cleaning the deflector 11 using such a deflector cleaning device 10 will be described.

  FIG. 4 is a flowchart showing a deflector cleaning method according to an embodiment of the present invention.

  As shown in FIG. 4, first, the lid 12 b of the chamber 12 is opened using the handle 17 provided on the side surface thereof, and the deflector 11 fixed to the adapter 20 is placed on the plurality of columns 19. Then, the lid 12b is closed (S101).

  Next, a deflector cleaning program (recipe) stored in the PC 31 is selected and executed (S102). Thereby, the deflector cleaning device 10 starts a series of cleaning operations.

  First, a downflow with a predetermined wind speed is generated in the chamber 12 (S103). The wind speed of the downflow is adjusted by the blower control unit 26 by automatically adjusting the rotational speed of the blower 14b based on the detection result by the anemometer 28. The wind speed may be adjusted manually by the manual butterfly valve 24.

  Next, the moving mechanism 18 is controlled to rotate the deflector 11 stepwise and move it stepwise in the vertical direction. At the same time, the ionizer 13 is driven, and ionized compressed air having a predetermined pressure / flow rate is ejected from the plurality of selected nozzle portions 13c in accordance with the position of the deflector 11, thereby cleaning the deflector 11. (S104).

  When the ionizer 13 takes in compressed air in the gas control box 13a, the ionizer 13 dehumidifies the air with a dryer. The dehumidified air is controlled by a filter regulator so as to reach a desired pressure based on the pressure detected by the pressure gauge. The compressed air having a desired pressure flows through the plurality of selected pipes 13b and is supplied to the nozzle portion 13c connected to the selected pipe 13b. Note that the flow rate of the compressed air flowing through each pipe 13b is controlled by the needle valve so as to be a desired flow rate based on the flow rate detected by the flow meter. The compressed air supplied to the nozzle portion 13 c is ionized at the tip of the nozzle portion 13 c and is ejected onto the surface of the deflector 11 at a predetermined pressure / flow rate.

  During cleaning of the deflector 11, the pressure / flow rate of the compressed air ejected from the selected nozzle portion 13 c is controlled so that ionized compressed air having a predetermined wind speed is ejected substantially uniformly onto the surface of the deflector 11. The The plurality of selected nozzle portions 13c are switched ON / OFF by an electromagnetic valve so that compressed air ionized from the plurality of nozzle portions 13c adjacent to each other is not simultaneously ejected. This is to prevent the ions that are ejected from canceling out.

  In addition, during the cleaning of the deflector 11, it is preferable to always monitor the downflow wind speed with the anemometer 28. Even if the position of the selected nozzle 13c and the pressure / flow rate of the ionized compressed air fluctuate, the amount of exhaust from the blower 14b is controlled so as to keep the downflow wind speed constant. The downflow can be stabilized by appropriately controlling the flow.

  During cleaning, it is preferable to always monitor the number of particles by the particle counter 15a. In addition to grasping the variation in the number of particles, it is possible to feed back to a cleaning program (recipe) so as to remove particles more efficiently. Furthermore, it is preferable to collect particles by the particle collecting device 15b. The particle source can be specified.

  The particle counter 15a, the particle collecting device 15b, and the anemometer 28 are arranged in the vicinity of the side surface of the chamber body 12 so as not to come into contact with the plurality of columns 19 rotated by the moving mechanism 18 during cleaning of the deflector 11. Is done.

  When a series of cleaning operations for the deflector 11 is executed, it is determined using the particle counter 15a whether or not the cleaning of the deflector 11 has been completed. First, in order to measure the amount of particles with higher accuracy, the particle counter controller 27 moves the particle counter 15a to the center of the chamber body 12a (S105), and detects the amount of particles (S106).

  If the amount of particles is equal to or greater than the threshold (for example, 1 or greater) (No in S107), it is determined that the cleaning of the deflector 11 has not been completed, and the deflector cleaning device 10 performs the cleaning operation again.

  The cleaning operation to be executed again may be in accordance with, for example, the previously selected cleaning program (recipe). Further, the cleaning program (recipe) changed based on the change tendency (history) of the particle amount detected during the cleaning operation may be followed.

  For example, when ionized compressed air is mainly ejected from the first nozzle portion 13 c-1, if the amount of detected particles increases compared to that before, a large amount of It can be seen that particles are attached. In this case, the cleaning operation executed again is effectively changed by changing the operation of ejecting compressed air ionized from the first nozzle portion 13c-1 to a cleaning program (recipe) mainly. It can be carried out.

  As a result of the detection of the particle amount, when the particle amount becomes less than a threshold value (for example, 0) (Yes in S107), it is determined that the cleaning of the deflector 11 is completed. After the down flow in the fan 12a and blower 14b chamber 12 is stopped (S108), the lid 12b of the chamber 12 is opened, and the deflector 11 fixed to the adapter 20 is taken out (S109).

  In this way, the deflector 11 is automatically cleaned.

  As described above, according to the deflector cleaning device and the deflector cleaning method according to the present embodiment, the cleaning operation of the deflector 11 is automatically executed according to the cleaning program. Therefore, the cleaning quality can be made uniform.

  Further, since the amount of particles peeled off from the deflector 11 can be detected by the particle counter 15a at a predetermined position, it is possible to improve the detection accuracy of the particles, and this also makes the cleaning quality uniform. Can be achieved.

  Further, in the past, the deflector was cleaned using the nozzle portion of one ionizer, but the cleaning time of the deflector 11 was reduced because the deflector 11 was cleaned using the plurality of nozzle portions 13c simultaneously. Can be shortened. For example, in the past, it took about 5 hours to clean the deflector 11 once. However, when the deflector 11 is cleaned using, for example, six nozzle portions 13c simultaneously, the cleaning work of the deflector 11 is performed. Can be shortened to about 1/6 of the conventional one.

  Further, by automating the cleaning operation, the details of the deflector 11 can be accurately cleaned, and the cleaning quality is improved. As a result, the assembly time of the deflector 11 can be shortened.

  That is, since the deflector 11 is required to be clean, conventionally, about 1/3 of the time required for the assembly process of the deflector 11 has been spent on the cleaning work. On the other hand, according to the deflector cleaning device 10 and the deflector 11 cleaning method according to the present embodiment, the cleaning quality is improved. Therefore, the deflector 11 should be cleaned only at the end of the assembly process of the deflector 11. It is sufficient, and the time spent for the cleaning work can be shortened.

  Furthermore, by automating the cleaning operation, it is possible to clean the deflector 11 at all times including, for example, nights and holidays. Therefore, the manufacturing cost of the deflector 11 and the manufacturing cost of the charged beam drawing apparatus in which the deflector 11 is incorporated can be suppressed.

  Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Deflector cleaning device 11 ... Deflector 12 ... Chamber 12a ... Chamber main body 12b ... Lid 13 ... Ionizer 13a ... Ionizer main body 13b ... Piping 13c, 13c -1, 13c-2, 13c-3 ... Nozzle 14 ... Airflow control mechanism 14a ... Fan 14b ... Blower 15 ... Particle detector 15a ... Particle counter 15b ... Particle Collection device 16 ... mount 17 ... handle 18 ... moving mechanism 19 ... support 20 ... adapter 21 ... screw 22 ... through hole 23 ... filter 24 ... manual Butterfly valve 25 ... outlet 26 ... blower control unit 27 ... particle counter controller 28 ... anemometer 29 ... anemometer Controller 30 ... various power 31 ··· PC (control unit)
32 ... Rack

Claims (5)

A deflector cleaning device for cleaning a deflector used in a charged beam lithography apparatus,
A chamber;
A support for mounting the deflector in the chamber;
A moving mechanism that is disposed at a lower portion of the support, rotates the support, and moves the support in the vertical direction;
An ionizer having a plurality of nozzle portions for ejecting ionized gas into the chamber;
An airflow control mechanism for generating a downflow in the chamber;
In the chamber, a particle detection device disposed above the moving mechanism and below the deflector;
Comprising
The plurality of nozzle portions are a first nozzle portion that ejects the ionized gas from above to below the chamber;
A second nozzle part for ejecting the ionized gas in a horizontal direction from a side surface of the chamber;
A third nozzle part for ejecting the ionized gas obliquely upward from the side surface of the chamber;
A deflector cleaning device.   2. The deflection according to claim 1, further comprising a control unit that selects the plurality of nozzle portions from which the ionized gas is ejected so that the ionized gas is not ejected simultaneously from the plurality of nozzle portions adjacent to each other. Detergent cleaning device.   2. The cleaning device for a deflector according to claim 1, wherein the chamber has a shape in which at least an upper diameter is larger than a lower diameter.   2. The deflector cleaning device according to claim 1, wherein the air flow control mechanism controls the wind speed so that the wind speed of the downflow in the chamber is constant. A cleaning method for a deflector for cleaning a deflector used in a charged beam drawing apparatus,
Place the deflector on the support installed in the chamber,
While rotating the support and moving the support in the vertical direction by moving the support in the chamber, the ionized gas is ejected to the upper surface, the side surface, and the lower surface of the deflector Remove the particles adhering to the deflector,
Generate a down flow in the chamber, move the peeled particles downward,
A deflector cleaning method for detecting the particles at a lower portion of the deflector and determining whether or not cleaning of the deflector is completed.

Images