JP2012132055A - Vacuum rotation drive device and vacuum treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering apparatus which can stabilize the ground of a shutter plate when target cleaning is performed.SOLUTION: A movable shutter device 2 has a forward/backward moving device 45 for moving a grounding member 43 toward a rotation axis 27 of a motor for introducing torque into a vacuum vessel. The grounding member 43 is brought into contact with the rotation axis 27 to ground a shutter plate 21 connected to the rotation axis 27. When target cleaning is performed by using the shutter plate 21 as a dummy substrate, the grounding member 43 can be brought into contact with the rotation axis 27 to strengthen the grounding action of the shutter plate 21.

Description

  The present invention relates to a vacuum rotation driving device and a vacuum processing device, and in particular, a vacuum that is provided in a vacuum processing device used for film formation of a semiconductor, a magnetic storage medium, a flat panel display, etc., and can obtain a stable ground. The present invention relates to a rotation driving device and a vacuum processing apparatus including the vacuum rotation driving device.

  In a sputtering apparatus that is a film forming process processing apparatus in semiconductor manufacturing or magnetic storage media, a target that is a consumable is periodically replaced with a new one. Since the new target is stored in the atmosphere, the surface thereof is oxidized or impurities are attached. Further, a reattached film is deposited on the surface of the target during sputtering, which may substantially deteriorate the performance of the sputtering film. In order to eliminate these inconveniences, target cleaning for periodically cleaning the target surface is performed.

  As a specific method of target cleaning, there is known a method of removing foreign matter on the surface of a target by performing dummy sputtering on a dummy substrate with electric power larger than that of a normal process. Furthermore, in order to reduce the cost of the dummy substrate, a method is known in which a shutter plate rotatably disposed in the process chamber is used as the dummy substrate.

  In general sputtering processing, a process gas is introduced into a chamber with a substrate placed in a substrate holder in the process chamber, a process of supplying power to a target to perform sputtering, and time power corresponding to the amount of film formation. After supplying the substrate, a series of steps such as a step of stopping the supply of electric power and process gas and evacuating the substrate, and a step of unloading the substrate to the transfer chamber are included.

  By repeating the sputtering process, the target disappears, and when it becomes a predetermined thickness, it is replaced with a new target. In addition, during sputtering, the particles that have jumped out of the target may not adhere to the substrate and re-adhere to the target surface. If a film is formed on the substrate in a state where a reattached film or foreign matter is generated, the desired film forming performance cannot be achieved, and thus periodic target cleaning is required.

  In target cleaning using a shutter plate, a process gas is introduced in a state where the shutter plate is opposed to the target, and foreign matter on the target surface is removed by performing dummy sputtering. The shutter plate is movably attached by a movable shutter mechanism, and is disposed at a position away from the target during the film forming process, and can be disposed at a position facing the target by a motor during target cleaning.

  An example of a conventional movable shutter device will be described with reference to FIG. 6 (see, for example, Patent Documents 1 and 2). The movable shutter device 101 is a mechanism for transmitting rotational power into the vacuum. The shaft joint 104 that connects the motor 103 and the shutter plate 105 with the vacuum seal portion 102 that separates the atmosphere and the vacuum interposed therebetween, and the motor 103 And a bearing 107 as a guide for the rotating shaft. By supplying electric power to the motor 103 based on the read value of the encoder, the shutter plate 105 can be rotated at a position facing the target TG and a position completely separated from the target TG. This movable shutter device 101 has a structure in which a shutter plate 105 is grounded via a bearing 107.

JP-A-8-92764 JP-A-9-63959

  In sputtering using an RF power source, the earth as an electric flow path plays an important role. For example, when the ground is unstable, the film quality deteriorates due to deterioration of film formation performance, which may cause noise to peripheral sensors and electrical components, or induce arcing or discharge at unexpected locations. There is a possibility.

  However, in the conventional movable shutter device 101, since the shutter plate 105 is grounded through the bearing 107, point contact is made between the ball of the bearing 107 and the inner ring, and between the ball and the outer ring. It was getting expensive. Therefore, it is desirable to strengthen the ground of the shutter plate 105 in order to increase the applied RF power.

  An object of the present invention is to provide a sputtering apparatus that can stabilize the ground of a shutter plate when performing target cleaning in view of the above-described problems of the prior art.

  A vacuum rotation driving device according to the present invention includes a casing attached to a vacuum vessel, a conductive rotation shaft that is rotatably supported by the casing and partially disposed in the vacuum vessel, and a permanent shaft provided on the rotation shaft. A magnet, a stator provided on the casing facing the permanent magnet, and a forward / backward movement device for moving the grounding member, which is always grounded, forward and backward toward the rotation shaft. The rotating shaft is brought into contact or the ground member is moved away from the rotating shaft.

  According to the present invention, the grounding of the shutter plate during target cleaning can be ensured, the target cleaning of the sputtering apparatus can be stably performed, the risk of occurrence of arc, noise, etc. is reduced, and the reliability of the apparatus is improved. improves. Moreover, the operation rate of a vacuum processing apparatus can be improved by that.

  In addition, the stabilization of the ground can stabilize the film quality, and the power loss of the power source can be reduced by efficiently supplying power to the sputtering space, thereby reducing the power consumption.

It is the schematic of the sputtering device which concerns on one Embodiment of this invention. It is the schematic of the movable shutter apparatus which concerns on one Embodiment of this invention. It is an enlarged view of the advance / retreat apparatus of the movable earth unit which concerns on one Embodiment of this invention. It is an enlarged view of the socket which concerns on one Embodiment of this invention. It is a structural example of the control system of the sputtering device which concerns on one Embodiment of this invention. It is the schematic of the conventional movable shutter apparatus.

  Below, the vacuum rotation drive device and vacuum processing apparatus which concern on each embodiment of this invention are demonstrated below. The members, arrangements, and the like described below are examples embodying the invention and do not limit the present invention, and it is needless to say that various modifications can be made in accordance with the spirit of the present invention. The application of the vacuum rotation driving device according to the present invention is not limited to the sputtering device, but can be applied as a rotation introducing device that needs to ensure a stable ground in the vacuum vessel.

  1 to 5 show a preferred embodiment of a sputtering apparatus and a vacuum rotation driving apparatus according to the present invention. FIG. 1 is a schematic view of a sputtering apparatus, FIG. 2 is a schematic view of a movable shutter apparatus, and FIG. FIG. 4 is an enlarged view of a socket, and FIG. 5 shows a configuration example of a control system of a sputtering apparatus.

First, the sputtering apparatus 1 according to the present embodiment will be outlined with reference to FIG.
The sputtering apparatus 1 (vacuum processing apparatus) includes a vacuum vessel 11 (hereinafter referred to as a chamber 11), a substrate holder 15 that holds a substrate W in the chamber 11, a target electrode 17 that holds a target TG, a shutter plate 21, and a shutter driving device. 25. As will be described later, the movable shutter device 2 (vacuum rotation driving device) is configured by attaching the shutter plate 21 to the shutter driving device 25.

  The chamber 11 includes a vacuum gauge PG for monitoring the pressure in the chamber, a gas introduction system 13 for introducing process gas into the chamber, a vacuum exhaust system (not shown) for evacuating the chamber internal space, and a decompressed chamber. A vent piping system (not shown) for returning the inside to atmospheric pressure is provided, and a power source (not shown) that supplies power to the target electrode 17 is connected to the target electrode 17. The chamber 11 is connected to an adjacent transfer chamber via a gate valve GV, and a transfer system for transferring the substrate is provided in the transfer chamber. Usually, the chamber 11 and the substrate holder 15 are grounded.

  The movable shutter device 2 as a vacuum rotation driving device is a device that moves the shutter plate 21 in the horizontal direction (direction parallel to the film-forming surface of the substrate) by the shutter driving device 25, and the position facing the target TG, the target The shutter plate 21 can be moved between a position completely away from the TG. That is, the movable shutter device 2 can arrange the shutter plate 21 at a position away from the target during sputtering film formation, and can arrange the shutter plate 21 at a position facing the target TG during target cleaning. Note that target cleaning is a processing step for removing a film that has reattached to the target surface.

Next, the movable shutter device will be described with reference to FIG.
As described above, the movable shutter device 2 is a rotary shutter device for changing the arrangement position of the shutter plate 21 according to the processing step by the shutter drive device 25, and includes the shutter drive device 25, the shutter plate 21, and the movable ground. A unit 40 is included as a main component. The shutter driving device 25 includes a rotating shaft 27 disposed so as to partially protrude from the opening 11 a of the chamber 11 into the chamber, a stator 29 disposed around the radial direction of the rotating shaft 27, and the rotating shaft 27. And a casing 31 for holding the stator 29. The shutter plate 21 is connected to a rotary shaft 27 via a shaft joint 28 inside the chamber. The shutter plate 21, the shaft joint 28, and the rotary shaft 27 are all configured to be conductive.

  The upper end of the casing 31 is airtightly attached to the chamber 11, and a pair of bearings 37 that support the stator 29 and the rotating shaft 27 are attached to the inner peripheral side. The bearing 37 is a member for supporting the rotating shaft 27, and it is desirable to use a vacuum bearing that hardly generates particles. The stator 29 is composed of a coil group that generates a magnetic force when electric power is applied. A vacuum partition 39 is provided between the stator 29 and the rotating shaft 27, and the rotating shaft 27 is divided on the vacuum side and the stator 29 (coil) is divided on the atmosphere side. The rotating shaft 27 is supported so that the gap with the vacuum partition wall 39 is as small as possible. In this specification, for convenience, the chamber 11 side of the rotating shaft 27 is described as the upper side (upper side), and the surface perpendicular to the rotating shaft 27 is described as the horizontal direction.

  A permanent magnet is provided on the outer peripheral portion of the rotating shaft 27 at a position facing the stator 29, and a brushless DC motor is configured with the stator 29. The shutter plate 21 rotates as the rotary shaft 27 rotates, and moves between the cleaning position and the process position. The cleaning position of the shutter plate 21 refers to a state in which the shutter plate 21 is positioned facing the target TG (target electrode 17) and the shutter plate 21 covers the target TG (target electrode 17). . On the other hand, the process position of the shutter plate 21 refers to a state in which the shutter plate 21 is positioned away from above the target TG and there is no region facing the target TG.

  A rotation sensor having a linear scale and an encoder 51 is provided on the lower side of the rotation shaft 27 (on the side opposite to the end portion to which the shutter plate 21 is attached). The encoder 51 is a known sensor composed of a magnetic sensor such as a Hall element fixed on the casing 31 side, and can detect a change in magnetism of a linear scale fixed on the rotating shaft 27 side. When an encoder composed of a projector and a light receiver is used, a disk whose light projection rate and coloring are changed at predetermined intervals is used instead of the linear scale.

  By controlling the power supplied to the stator 29 based on information obtained from the encoder 51, a position facing the target electrode 17 (cleaning position) and a position completely separated from the position facing the target electrode 17 (process position). The shutter plate 21 is controlled. Further, at the bottom of the casing 31, there is a feed-through 53 for routing a power cable, a signal cable, an encoder cable, etc. (all not shown) connected to the stator 29 to the outside of the casing.

Here, the movable earth unit 40 will be described.
The movable earth unit 40 is a device that is electrically connected to the rotating shaft 27 at a predetermined timing and grounds the shutter plate 21 via the shaft joint 28 and the rotating shaft 27. The movable earth unit 40 includes an earth member 43 that can come into contact with the rotating shaft, an advance / retreat device 45 that moves the earth member 43 forward and backward with respect to the rotating shaft 27, and a bellows tube 47 that maintains the periphery of the earth member 43 on the vacuum side. have. In the present embodiment, the movable earth unit 40 is provided below the rotating shaft 27. A region inside the bellows tube 47 and the vacuum partition 39 is a region to be evacuated, and the rotating shaft 27 and the ground member 43 are arranged in this vacuum region (vacuum side).

  The earth member 43 is configured to move up and down by an advance / retreat device 45, and is attached so as to abut against and be electrically connected to the lowermost end portion of the rotary shaft 27 when moved upward. Yes. Since the ground member 43 is always grounded, the rotary shaft 27, the shaft joint 28, and the shutter plate 21 are all grounded with the rotary shaft 27 and the ground member 43 in contact with each other. In this embodiment, an air cylinder is used for the advance / retreat apparatus 45, but it goes without saying that other configurations for moving an object such as a motor and a feed screw mechanism can be applied.

  Note that the shutter plate 21 may be configured so that a shield arranged around the substrate holder 15 and a labyrinth structure can be assembled to prevent foreign matter from adhering to the surface of the substrate holder 15 during target cleaning. Specifically, a shutter lifting / lowering device that can move the shutter plate 21 up and down is further attached to the movable shutter device 2 so that a shield and a labyrinth structure around the substrate holder 15 can be formed when the shutter plate 21 is raised. .

  During normal process processing, the shutter plate 21 is in the process position, and the ground member 43 is lowered and separated from the rotating shaft 27 (separated position). At this time, the rotating shaft 27 is rotatable, and the shutter plate 21 is grounded only through the bearing 37. At the time of target cleaning, the shutter plate 21 is moved to the target cleaning position, and the ground member 43 is raised and is in contact with the rotary shaft 27 (contact position). At this time, the shutter plate 21 is in a state of being grounded through both the bearing 37 and the ground member 43. In the present embodiment, the locus of the vertical movement of the ground member 43 is set to be coaxial with the rotary shaft 27, but it is not necessary to be coaxial with the rotary shaft 27. For example, the ground member 43 may be configured to move up and down in the horizontal direction and to contact the outer peripheral surface of the rotating shaft 27.

Here, the movable earth unit will be described in detail with reference to FIGS.
FIG. 3 is an enlarged view of the advance / retreat apparatus for the movable earth unit. FIG. 3A is a view when the ground member 43 is in the separated position. FIG. 3 (b)
These are figures when the earth member 43 exists in a contact position. When the ground member 43 is in the contact position, the shutter plate 21 is firmly grounded by the ground member 43. In the present embodiment, a socket 49 for securing a contact area with the ground member 43 is attached to the rotating shaft 27.

  FIG. 4 shows a perspective view of the socket. The socket 49 has a conical shape with cuts and is made of a conductive material. The socket 49 is attached to the lower end of the rotating shaft 27 (a position in contact with the ground member 43). The tip of the ground member 43 is formed thinly in accordance with the shape of the inner surface of the socket 49, and the ground member 43 enters the socket 49 and can be stably contacted.

  The contact structure between the ground member 43 and the rotating shaft 27 shown in FIG. 4 is an example. As another example of the contact structure between the ground member 43 and the rotary shaft 27, for example, the bottom end of the rotary shaft 27 may be flattened and the tip of the ground member 43 may be flattened so that the flat surfaces come into contact with each other. Good.

At this time, the contact surface of the earth member 43 (or the contact surface of the rotating shaft 27) is deformed or inclined according to the contact surface of the rotating shaft 27 (or the contact surface of the earth member 43) so that the contact can be made more stably. It is desirable that the structure be
Further, the contact surface of the ground member 43 (or the contact surface of the rotating shaft 27) may be embossed so that the contact can be stably made at a large number of locations.

FIG. 5 shows a configuration example of a control system of the sputtering apparatus.
The sputtering apparatus is a system controlled by a controller using a PLC (program logic controller), and has an apparatus PLC and a unit PLC (unit program logic controller) as controllers. The device PLC is a controller that controls the operation of each unit PLC, the transport system (substrate transport), the gate valve GV, and the like. The transport system and the gate valve GV may be controlled via the unit PLC.
The unit PLC is a controller that controls a motor driver, an air operation (gas introduction system), a power supply (for example, an RF power supply), an exhaust system, and the like according to a command from the device PLC.

  The motor driver supplies power to the motor (stator 29) of the shutter driving device 25 in accordance with a command from the unit PLC. At this time, the shutter plate 21 is opened and closed by controlling the power based on the position information from the encoder 51. The air operation controls the gas introduction system by controlling the opening and closing of each valve according to a command from the unit PLC. Examples of the device controlled by the air operation include the advance / retreat device 45 and the gas introduction system 13. The advance / retreat device 45 (cylinder) of the movable earth unit 40 moves the rotary shaft 27 up and down by switching the air supply in response to a command from the air operation. The RF power supply also supplies power to the cathode electrode 17 through the matching box in response to a command from the unit PLC. The exhaust system is similarly controlled by a command from the unit PLC, and the pump is started and the valve is opened and closed by an air operation.

The present invention is not limited to the opening / closing device (movable shutter device 2) of the shutter plate 21, but can be widely used as a rotation introducing device for introducing a rotational force into the vacuum vessel. For example, it can be used for strengthening the earth of a roll in an apparatus (roll conveyance apparatus) that conveys using a roll. The conventional roll conveying device is structured to be grounded through a bearing in the same manner as the shutter opening / closing device. For this reason, there is a risk that the electrical resistance increases and the ground becomes unstable. By using the movable ground unit of the present invention, the ground can be strengthened only when necessary (when the process current is turned on). The maintenance interval can be increased compared to the method in which the brush is always in contact with the ground. In this case, since the roll is always rotating, the earth of the roll is strengthened by using a brush or the like for the earth connection portion. Also, the maintenance interval (brush life) can be extended by contacting the brush only when necessary (when the process current is input).

According to the present invention, the grounding of the shutter plate during target cleaning can be ensured, the target cleaning of the sputtering apparatus can be stably performed, the risk of occurrence of arc, noise, etc. is reduced, and the reliability of the apparatus is improved. improves. Moreover, the operation rate of a vacuum processing apparatus can be improved by that. In addition, the stabilization of the ground can stabilize the film quality, and the power loss of the power source can be reduced by efficiently supplying power to the sputtering space, thereby reducing the power consumption.

Further, since the gap between the rotating shaft 27 and the vacuum partition wall 39 is small at the lowermost end of the rotating shaft 27 and the gap between the rotating shaft 27 and the vacuum partition wall 39 is small, particles generated by the contact with the grounding member 43 are moved to the process chamber side. Outflow can be reduced. Further, since the lower space of the rotating shaft 27 has a high degree of freedom in design, a labyrinth structure (not shown) can be provided in the vicinity of the contact portion with the ground member 43 for further reduction.

TG Target PG Vacuum gauge GV Gate valve W Substrate 1 Sputtering device 2 Movable shutter device 11 Chamber 11a Opening portion 13 Gas introduction system 15 Substrate holder 17 Target electrode 21 Shutter plate 25 Shutter drive device 27 Rotating shaft 28 Shaft joint 29 Stator 31 Casing 37 Bearing 39 Vacuum bulkhead 40 Movable earth unit 43 Ground member 45 Advance / retract device 47 Bellows tube 49 Socket 51 Encoder 53 Feedthrough 101 Movable shutter device 102 Vacuum seal part 103 Motor 104 Shaft joint 105 Shutter plate 107 Bearing

Claims (4)

A casing attached to the vacuum vessel;
A conductive rotating shaft supported rotatably on the casing and partially disposed in the vacuum vessel;
A permanent magnet provided on the rotating shaft;
A stator provided in the casing facing the permanent magnet;
An advancing / retreating device for advancing / retreating a grounding member that is always grounded toward the rotating shaft,
The advancing / retreating device moves the grounding member so as to contact the rotating shaft or move the grounding member away from the rotating shaft. The vacuum rotation driving device according to claim 1, wherein both the rotating shaft and the ground member are disposed in a vacuum region. A substrate holder capable of holding a substrate;
A target electrode capable of holding a target;
A conductive shutter plate;
A vacuum processing apparatus provided with a movable shutter device capable of moving the shutter plate between a cleaning position facing the target electrode and a process position separated from the target electrode, in a vacuum container,
The vacuum processing apparatus according to claim 1, wherein the movable shutter device is a vacuum rotation driving device according to claim 1. The movable shutter device causes the ground member to abut on the rotating shaft when the shutter plate is at the cleaning position, and separates the ground member from the rotating shaft when the shutter plate is at the process position. The vacuum processing apparatus according to claim 3.