JP5505049B2 - Gripping device - Google Patents

Description

  The present invention relates to a gripping device, and more particularly, to a gripping device including a clamp portion for clamping a thin plate-like object.

  2. Description of the Related Art Conventionally, a gripping device including a clamp unit for clamping a thin plate-like object such as a wafer is known (see, for example, Patent Document 1).

  In Patent Document 1, an electromagnetic actuator having a drive shaft (solenoid actuator), a direction attached to the drive shaft of the electromagnetic actuator, and a direction in which a thin plate (wafer) is clamped along with the movement of the drive shaft of the electromagnetic actuator are A wafer handling robot hand (gripping device) including a clamp part that rotates in a clamping direction and a spring member that biases the clamp part in a direction of clamping the wafer is disclosed. In this wafer handling robot hand, when the wafer is clamped, the electromagnetic actuator is de-energized so that no thrust is generated in a direction against the biasing force of the spring member of the electromagnetic actuator. Is rotated in the direction of clamping the wafer to clamp the wafer. On the other hand, at the time of unclamping when the wafer is not clamped by the clamp portion, the clamp portion is unclamped by exciting the electromagnetic actuator to generate a thrust force in a direction against the biasing force of the spring member. Rotated in the direction.

  However, in the wafer handling robot hand described in Patent Document 1, when the wafer is clamped, the excitation of the electromagnetic actuator is turned off so that the clamping portion is rotated so as to clamp the wafer by the biasing force of the spring member. At the moment when the excitation of the electromagnetic actuator is cut off, the clamping portion is rotated at a large speed in the clamping direction by the biasing force of the spring member. For this reason, there is an inconvenience that an impact when clamping the wafer is increased.

  Therefore, conventionally, a technique for solving the above-described inconvenience has been proposed (for example, see Patent Document 2). In Patent Document 2, an electromagnetic actuator, a clamp portion attached to the electromagnetic actuator and gripping a thin plate-like object, and a clamp portion attached to the clamp portion for biasing the clamp portion in the direction of clamping the thin plate-like object are disclosed. A thin plate-like object gripping device including a spring member is disclosed. The electromagnetic actuator is provided with a position detector that detects the position of the thin plate-like object. In this gripping device, when the thin plate-like object is clamped, the position of the thin plate-like object is detected by the position detector when the clamp part moves in the direction of clamping the thin plate-like object by the biasing force of the spring member. By controlling the operation of the electromagnetic actuator based on the detection result by the detector, the moving speed of the clamp unit is controlled to be reduced before the clamp unit contacts the thin plate-like object. Thereby, the impact at the time of clamping a thin plate-shaped object by a clamp part can be relieved. On the other hand, when the thin plate-like object is not clamped by the clamp portion, the clamp portion is moved in the direction of unclamping by generating a thrust in a direction against the urging force of the spring member by the electromagnetic actuator.

JP 7-37960 A JP 2004-119554 A

  However, in Patent Document 2, it is possible to mitigate the impact when the thin plate-like object is clamped by the clamp portion, while a position detector for detecting the position of the thin plate-like object is additionally provided in the electromagnetic actuator. Therefore, there is a problem that the configuration of the electromagnetic actuator is complicated.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to use a position detector while mitigating the impact when a thin plate-like object is clamped by a clamp portion. It is an object of the present invention to provide a gripping device capable of suppressing the complication of the configuration of the electromagnetic actuator caused by the above.

Means for Solving the Problems and Effects of the Invention

In order to achieve the above object, a gripping device according to one aspect of the present invention is constantly biased in a direction of clamping a movable part of a clamp part including a movable part that moves in a direction of clamping a thin plate-like object. And at least an electromagnetic actuator that generates a thrust when shifting from the clamp-released state to the clamped state. The electromagnetic actuator moves in the clamping direction of the spring member when shifting from the clamp-released state to the clamped state. and the flat surface shape of the exciting coil for generating a thrust in the direction to reduce the speed of movement of the movable portion by the biasing force, including flat the excitation circuit and a permanent magnet provided so as to face the flat surface shape of the exciting coil is configured, the spring member includes a first spring member and second spring members are provided on both sides of the flat-type electromagnetic actuator, the electromagnetic Accession When the excitation circuit is switched from the on state to the off state when shifting from the clamp release state to the clamp state, the thrust of the electromagnetic actuator becomes smaller than the urging force that gradually decreases as the spring member extends. By gradually reducing the current flowing through the excitation circuit, the thrust is generated in a direction that reduces the moving speed of the movable part due to the biasing force of the spring member.

  In the gripping device according to this one aspect, as described above, the spring member that constantly urges the movable portion of the clamp portion in the clamping direction, and at least the clamp direction of the spring member when shifting from the clamp release state to the clamp state The thrust generated by the exciting coil when shifting from the clamped state to the clamped state by providing an electromagnetic actuator having an exciting coil that generates thrust in a direction that reduces the moving speed of the movable part due to the biasing force Since the moving speed of the movable part is reduced by this, it is suppressed that the clamp part contacts the thin plate-like object at a high speed. Thereby, since the impact at the time of clamping a thin plate-shaped object can be relieved, damage to a thin plate-shaped object and generation | occurrence | production of particles (dust) can be suppressed. In addition, a position detector that detects the position of a thin plate-like object is added to the electromagnetic actuator when clamping the thin plate-like object by controlling the speed of the clamping unit using an excitation circuit that is usually provided in the electromagnetic actuator. Since the moving speed of the movable part can be reduced without being provided, the complication of the configuration of the electromagnetic actuator due to the use of the position detector can be suppressed.

The electromagnetic actuator is movable by the biasing force of the spring member by gradually reducing the current flowing through the excitation circuit when the excitation circuit is switched from the on state to the off state when shifting from the clamp release state to the clamp state. It is comprised so that a thrust may be generated in the direction which reduces the moving speed of a part. This ensures, as the current flowing through the exciting circuit is gradually decreased, since the movable portion while reducing the moving speed of the movable portion can be gradually close to the thin plate material, a thin plate-like material Impact during clamping can be reduced.

  In this case, preferably, the excitation circuit includes a capacitor for storing the current of the excitation circuit, and when the excitation circuit is turned from the on state to the off state, the current flowing through the excitation circuit is caused to flow by passing the current stored in the capacitor. It is configured to gradually decrease. With this configuration, the current stored in the capacitor automatically decreases gradually with discharge, so the movable part is made into a thin plate while reducing the moving speed of the movable part simply by providing a capacitor in the excitation circuit. You can gradually approach the object.

  In the gripping device in which the current flowing through the excitation circuit is gradually decreased, the excitation circuit preferably includes a bypass circuit including a diode for causing a current to flow when a counter electromotive force is generated when the current is not flown when the switch is turned on and when a back electromotive force is generated. When the excitation circuit is switched from the on state to the off state, the current caused by the back electromotive force generated transiently in the excitation coil is passed through the bypass circuit, so that the current flowing through the excitation circuit gradually decreases. Has been. With this configuration, when the excitation circuit is switched from the on-state to the off-state, the excitation coil generates thrust in a direction that reduces the moving speed of the movable part due to the current caused by the back electromotive force that is transiently generated. The moving part can gradually approach the thin plate-like object while reducing the moving speed of the moving part.

  In the gripping device in which the current flowing through the excitation circuit is gradually reduced, preferably, the excitation circuit is provided so as to correspond to each of the plurality of excitation coils and the plurality of excitation coils, and the on / off operation of the plurality of excitation coils. When switching the excitation circuit from the on-state to the off-state, by controlling the plurality of switch sections so that the plurality of excitation coils are sequentially turned off, the current flowing through the excitation circuit is gradually increased. It is configured to decrease. If comprised in this way, since the number of the exciting coils which an electric current flows in steps can be reduced by turning off several switch parts sequentially, a movable part is made to approach a thin plate-like object in steps. be able to. In addition, the moving speed of the movable part can be more appropriately reduced by controlling the energization time of the excitation coils at each stage when the number of excitation coils through which current flows is reduced by sequentially turning off a plurality of excitation coils. The degree can be controlled.

  In the gripping device according to the above aspect, the clamp unit and the electromagnetic actuator are preferably used in a vacuum, and the electromagnetic actuator generates thrust even in the clamp release state in addition to the transition from the clamp release state to the clamp state. In the clamp-released state, the exciting circuit is turned on and a current is applied to generate a thrust in a direction against the biasing force of the spring member, so that the movable part is clamped in the clamping direction. In the clamped state, the exciting circuit is turned off and no current flows, so that no thrust is generated in the electromagnetic actuator and the movable member is clamped by the biasing force of the spring member. The clamp is performed by being energized. With this configuration, when the excitation circuit is turned on, a thrust against the biasing force of the spring member is generated in the electromagnetic actuator, and the movable part moves away from the thin plate. Can be brought into a clamp release state (unclamped state). Further, when the excitation circuit is turned off, for example, no current flows from the power source to the excitation circuit, so that heat generation in the excitation circuit can be suppressed. Thereby, since it is suppressed that an electromagnetic actuator becomes high temperature, an electromagnetic actuator can be used also in the vacuum where the heat | fever of an electromagnetic actuator is hard to radiate.

  In the gripping device according to the above aspect, the excitation circuit of the electromagnetic actuator is preferably configured so that the direction of the flowing current can be changed. In the clamped state, the current is applied in a direction opposite to that when the excitation circuit is on. By flowing, the electromagnetic actuator is configured to generate a thrust in a direction that assists the clamping force of the movable portion by the biasing force of the spring member. According to this configuration, when the biasing force of the spring member is weak and the thin plate-like object cannot be sufficiently clamped, the thrust of the electromagnetic actuator can be supplemented as the clamping force to the biasing force of the spring member. It can be clamped securely.

  In the gripping device according to the above aspect, the electromagnetic actuator preferably includes a flat linear motor. With this configuration, a flat linear motor can be used to reduce the thickness. Therefore, when used in a vacuum, a passage with a small height (gate valve opening) for accessing the vacuum apparatus is used. Part).

It is a schematic diagram which shows the multi-chamber type vacuum processing apparatus provided with the electromagnetic gripper by 1st Embodiment of this invention. It is a top view which shows the electromagnetic gripper by 1st Embodiment of this invention. It is a figure which shows the detail of the electromagnetic actuator of the electromagnetic gripper by 1st Embodiment of this invention. It is sectional drawing along the 300-300 line of FIG. FIG. 4 is a cross-sectional view taken along line 400-400 in FIG. 3. It is an equivalent circuit diagram in case the excitation circuit by 1st Embodiment of this invention is an ON state. It is an equivalent circuit diagram when the excitation circuit according to the first embodiment of the present invention is in an off state. It is a top view for demonstrating the wafer clamp state by 1st Embodiment of this invention. It is sectional drawing for demonstrating the wafer clamp state by 1st Embodiment of this invention. It is a figure which shows the state which the electromagnetic gripper by 1st Embodiment of this invention has passed through the opening part of the gate valve of a vacuum processing apparatus. It is an equivalent circuit diagram of the excitation circuit for demonstrating the modification of 1st Embodiment of this invention. It is an equivalent circuit diagram in case the excitation circuit by 2nd Embodiment of this invention is an ON state. It is an equivalent circuit diagram in case the excitation circuit by 2nd Embodiment of this invention is an OFF state. It is an equivalent circuit diagram in case the three switches of the excitation circuit by 3rd Embodiment of this invention are in an ON state. It is an equivalent circuit diagram in case two switches of the excitation circuit by 3rd Embodiment of this invention are in an ON state. It is an equivalent circuit diagram in case one switch of the excitation circuit by 3rd Embodiment of this invention is an ON state. It is an equivalent circuit diagram in case the switch of the excitation circuit by 3rd Embodiment of this invention is an OFF state. It is an equivalent circuit schematic of the excitation circuit containing the current control circuit by 4th Embodiment of this invention. It is the graph which showed the relationship between the exciting current at the time of turning off the exciting circuit by 4th Embodiment of this invention, and time.

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

(First embodiment)
With reference to FIGS. 1-5, the vacuum processing apparatus 200 provided with the electromagnetic gripper 100 by 1st Embodiment of this invention is demonstrated. The electromagnetic gripper 100 is an example of the “gripping device” in the present invention.

  The multi-chamber type vacuum processing apparatus 200 including the electromagnetic gripper 100 according to the first embodiment of the present invention includes four vacuum processing units 1, 2, 3 and 4 as shown in FIG. The vacuum processing units 1 to 4 are provided on the outer periphery of the transfer chamber 5. Note that the inside of the transfer chamber 5 is maintained at a predetermined degree of vacuum. In addition to the transfer chamber 5, load lock chambers 6 and 7 are provided on the outer periphery of the transfer chamber 5. A load / unload chamber 8 is provided on the opposite side of the load lock chambers 6 and 7 from the transfer chamber 5. On the opposite side of the loading / unloading chamber 8 from the load lock chambers 6 and 7, there are provided three ports 11 for attaching carriers 10 capable of accommodating semiconductor wafers 9 as substrates to be processed. The wafer 9 is an example of the “thin plate” in the present invention.

  The vacuum processing units 1 to 4 are connected to the periphery of the transfer chamber 5 via a gate valve 12. Further, by opening the gate valve 12, the transfer chamber 5 and the vacuum processing units 1 to 4 are connected, and by closing the gate valve 12, the transfer chamber 5 and the vacuum processing units 1 to 4 are shut off. Further, the load lock chambers 6 and 7 are connected to the transfer chamber 5 through the gate valve 12a, respectively. The load lock chambers 6 and 7 are connected to the carry-in / out chamber 8 via the gate valve 12a, respectively. The load lock chambers 6 and 7 are connected to the transfer chamber 5 by opening the gate valve 12a, and are disconnected from the transfer chamber 5 by closing the gate valve 12a. The load lock chambers 6 and 7 are connected to the loading / unloading chamber 8 by opening the gate valve 12a, and are blocked from the loading / unloading chamber 8 by closing the gate valve 12a.

  In the transfer chamber 5, a horizontal articulated wafer transfer robot 5 a for loading and unloading the wafer 9 with respect to the vacuum processing units 1 to 4 and the load lock chambers 6 and 7 is provided. The wafer transfer robot 5a is disposed substantially at the center of the transfer chamber 5, and is configured to be capable of turning and extending / contracting by driving a plurality of joints, and has an electromagnetic gripper 100 provided at the tip of the arm portion. Yes.

  As shown in FIG. 2, the electromagnetic gripper 100 is provided so as to extend from the root portion 100 b, has a substantially U shape, and has a support arm 100 a for supporting the wafer 9. On the surface of the support arm 100 a of the electromagnetic gripper 100, two fixed claws 20 at the tip for clamping (gripping) the wafer 9 and two wafer sliding members 21 for sliding the wafer 9 are provided. It has been.

  An electromagnetic actuator 22 is provided on the surface of the root portion 100b of the electromagnetic gripper 100 on the arrow X2 direction side. The electromagnetic actuator 22 includes a flat linear motor including flat surface-shaped exciting coils 27a to 27c, which will be described later, and permanent magnets 29a to 29f (see FIG. 3). Further, the electromagnetic actuator 22 includes a fixed portion 23 and a clamp portion 24 that can move (slide) in the X direction with respect to the fixed portion 23. The clamp unit 24 includes a movable unit 25 that can move in the direction of clamping the wafer 9 (arrow X1 direction) and a movable claw 26 for clamping the wafer 9.

  In the first embodiment, as shown in FIG. 3, the fixing portion 23 includes an excitation circuit 28 having three spiral excitation coils 27a, 27b, and 27c. The three exciting coils 27a to 27c are arranged so as to be adjacent along the X direction and are connected in series. The movable portion 25 includes six permanent magnets 29a, 29b, 29c, 29d, 29e, and 29f arranged to face the exciting coils 27a to 27c of the fixed portion 23. Each of the six permanent magnets 29a to 29f is formed so as to extend in the Y direction, and is disposed so as to be adjacent along the X direction. Further, as shown in FIG. 4, the permanent magnets 29a, 29b, 29c, 29d, 29e, and 29f are S poles, N poles, S poles, N poles, and S poles as viewed from the upper surface side (arrow Z1 direction side). , N poles, and N poles, S poles, N poles, S poles, N poles, and S poles as viewed from the lower surface side (arrow Z2 direction side). Further, the exciting coils 27a to 27c are arranged so as to intersect with the magnetic field in the Z direction generated in the permanent magnets 29a to 29f.

  Further, as shown in FIG. 3, a DC power source 40 described later is connected to the three exciting coils 27a to 27c connected in series. The three exciting coils 27a to 27c are configured to be supplied with a direct current from a direct current power source 40. When current is supplied to the three exciting coils 27a to 27c, as shown in FIG. A thrust (electromagnetic force) is generated in the direction of the arrow X2 between the current flowing through the three exciting coils 27a to 27c and the magnetic field generated from the six permanent magnets 29a to 29f. In addition, when no current is supplied to the exciting coils 27a to 27c, no thrust is generated between the exciting coils 27a to 27c and the permanent magnets 29a to 29f, and the movable portion 25 has a spring member 30 described later. It is configured to move in the direction of arrow X1 by the urging force. The movable portion 25 is configured to move (slide) so that the wafer 9 is pressed against the two fixed claws 20 on the arrow X1 direction side when the movable claw 26 contacts the wafer 9. Thus, the wafer 9 is clamped by the movable claw 26 and the two fixed claws 20. The thrust generated between the exciting coils 27 a to 27 c and the permanent magnets 29 a to 29 f is configured to be larger than the urging force of the spring member 30.

  As shown in FIG. 3, a spring member 30 is disposed between the fixed portion 23 and the movable portion 25. This spring member 30 consists of a compression spring, and is provided one each on the arrow Y1 direction side and the arrow Y2 direction side of the movable part 25. Further, the spring member 30 is configured so as to always be urged in a direction (arrow X1 direction) in which the movable portion 25 is clamped.

  Further, one linear guide 31 for guiding the movement of the movable part 25 in the X direction is provided on each side of the movable part 25 in the direction of the arrow Y1 and in the direction of the arrow Y2. As shown in FIG. 5, the linear guide 31 includes a slider 32 provided on the movable portion 25 side and a rail 33 provided on the fixed portion 23 side. The slider 32 on the movable portion 25 side is fixed. It is configured to slide (slide) on the rail 33 on the part 23 side along the X direction. Further, as shown in FIG. 3, the stoppers 34a and 34b for restricting the movable portion 25 from moving in the X direction are respectively provided on the arrow X1 direction side and the arrow X2 direction side of the fixed portion 23. It is provided one by one.

  Next, a detailed configuration of the excitation circuit 28 will be described with reference to FIG.

  In the first embodiment, the excitation circuit 28 includes the above-described three excitation coils 27a to 27c connected in series, a DC power source 40 for supplying a DC current to the excitation coils 27a to 27c, and an electric current for storing the current. A capacitor 35 and a switch unit 41 are included. The + terminal of the DC power supply 40 is connected to one end of the exciting coil 27 a and one electrode of the capacitor 35. The other end of the exciting coil 27a is connected to one end of the exciting coil 27b, and the other end of the exciting coil 27b is connected to one end of the exciting coil 27c. The other end of the exciting coil 27 c and the other electrode of the capacitor 35 are connected to one end of the switch unit 41. The other end of the switch unit 41 is connected to the negative terminal of the DC power supply 40.

  Next, the operation of the electromagnetic gripper 100 will be described with reference to FIGS. 4 and 6 to 10.

  First, when releasing the clamping state of the wafer 9 (the state of clamping the wafer 9), the switch unit 41 is turned on (the excitation circuit 28 is turned on) as shown in FIG. A current is supplied to the coils 27 a to 27 c and the capacitor 35. At this time, the capacitor 35 is charged (charged) with a current. In addition, the movable portion 25 is moved by the arrow X1 of the spring member 30 by the thrust (electromagnetic force) generated between the current flowing through the exciting coils 27a to 27c and the magnetic field generated from the permanent magnets 29a to 29f (see FIG. 4). It moves in the direction of arrow X2 so as to overcome the urging force in the direction. When the movable portion 25 comes into contact with the stopper 34b on the arrow X2 direction side, the movement of the movable portion 25 is stopped and the clamp is released (the wafer 9 is not clamped).

  Next, when shifting from the clamp release state to the clamp state, the switch unit 41 is turned off (the excitation circuit 28 is turned off), and current supply from the DC power supply 40 to the excitation coils 27a to 27c is stopped. Here, in the first embodiment, as shown in FIG. 7, the excitation circuit 28 of the electromagnetic actuator 22 shifts from a clamp release state (a state where the wafer 9 is not clamped) to a clamp state (a state where the wafer 9 is clamped). When the excitation circuit 28 is changed from the on state to the off state, the current stored in the capacitor 35 is caused to flow, whereby the current flowing through the excitation circuit 28 is gradually reduced, so that the spring member 30 is clamped (arrow) Thrust is generated in a direction (arrow X2 direction) in which the moving speed of the movable portion 25 is reduced by the urging force in the X1 direction.

  That is, when shifting from the clamp release state to the clamp state, the capacitor 35 is charged when the clamp state is released, so that current is supplied from the capacitor 35 to the exciting coils 27a to 27c. Thereby, between the electric current which flows into excitation coil 27a-27c, and the magnetic field which generate | occur | produces from permanent magnet 29a-29f (refer FIG. 4), it is smaller than the urging | biasing force of the spring member 30, and is a direction opposite to urging | biasing force. A thrust (electromagnetic force) in the direction of arrow X2 is generated. Due to the thrust (electromagnetic force) in the arrow X2 direction, a part of the urging force in the arrow X1 direction by the spring member 30 acting on the movable portion 25 is canceled and reduced, so that the moving speed of the movable portion 25 is reduced. The moving claw 26 is slowly moved in the direction of the arrow X1 in the state of being in contact with the wafer 9 at a low speed. As a result, the state shown in FIGS. 8 and 9 is obtained. The thrust generated in the direction of the arrow X2 is gradually reduced as the current stored in the capacitor 35 is discharged. Therefore, the biasing force in the direction of the arrow X1 of the spring member 30 acting on the wafer 9 via the movable claw 26 is used. (Pressing force) gradually increases. As the urging force of the spring member 30 in the arrow X1 direction acting on the wafer 9 increases, the wafer 9 starts moving in the arrow X1 direction and comes into contact with the fixed claw 20. Thereafter, when the current stored in the capacitor 35 is completely discharged, no thrust is generated, and only the urging force of the spring member 30 acts on the wafer 9 to be in a clamped state. Thereafter, as shown in FIG. 10, the clamped wafer 9 passes through the gate valve 12 (12a) having a small height of the vacuum processing apparatus 200, or the vacuum processing units 1 to 4 or the load lock chambers 6 and 7 are placed. To be transported.

  In the first embodiment, as described above, the spring member 30 that constantly urges the movable portion 25 of the clamp portion 24 in the direction in which the movable portion 25 is clamped (the direction of the arrow X1), and the spring when the transition from the clamp release state to the clamp state occurs. By providing an electromagnetic actuator 22 having exciting coils 27a to 27c that generate thrust in a direction (arrow X2 direction) in which the moving speed of the movable portion 25 is reduced by the urging force of the member 30 in the clamping direction, When shifting to the clamp state, the moving speed of the movable portion 25 is reduced by the thrust generated by the excitation coils 27a to 27c, so that the clamp portion 24 is prevented from contacting the wafer 9 at a high speed. . Thereby, since the impact at the time of clamping the wafer 9 can be relieved, damage to the wafer 9 and generation of particles (dust) can be suppressed. In addition, by controlling the speed of the clamp unit 24 using the excitation circuit 28 provided in the normal electromagnetic actuator 22, a position detector that detects the position of the wafer 9 is clamped to the electromagnetic actuator 22 when the wafer 9 is clamped. Since the moving speed of the movable part 25 can be reduced without additionally providing, the complexity of the configuration of the electromagnetic actuator 22 resulting from the use of the position detector can be suppressed.

  In the first embodiment, as described above, when the electromagnetic actuator 22 changes the excitation circuit 28 from the on state to the off state when the clamper moves from the clamp release state to the clamp state, the current flowing through the excitation circuit 28 gradually increases. As a result, the thrust is generated in a direction that reduces the moving speed of the movable portion 25 due to the biasing force of the spring member 30. As a result, as the current flowing through the excitation circuit 28 gradually decreases, the movable portion 25 can gradually approach the wafer 9 while reducing the moving speed of the movable portion 25. Impact during clamping can be reduced.

  In the first embodiment, as described above, when the excitation circuit 28 is switched from the on state to the off state, the current flowing through the excitation circuit 28 is gradually decreased by flowing the current stored in the capacitor 35. As a result, the current stored in the capacitor 35 is automatically gradually reduced with discharge. Therefore, the movable part 25 is moved to the wafer 9 while reducing the moving speed of the movable part 25 only by providing the capacitor 35 in the excitation circuit 28. Can be gradually approached.

  In the first embodiment, as described above, in the clamp release state, the excitation circuit 28 is turned on and a current flows, whereby a thrust in a direction against the urging force of the spring member 30 is applied to the electromagnetic actuator 22. The generated movable portion 25 is moved in the direction opposite to the clamping direction. In the clamped state, the exciting circuit 28 is turned off and no current flows, so that no thrust is generated in the electromagnetic actuator 22 and the spring member 30 is moved. Clamping is performed by urging the movable portion 25 in the direction of clamping by the urging force. Thereby, when the excitation circuit 28 is turned on, a thrust against the biasing force of the spring member 30 is generated in the electromagnetic actuator 22 and the movable part 25 moves away from the wafer 9, so that the wafer 9 can be easily clamped. It can be in a released state (unclamped state). Further, when the excitation circuit 28 is turned off, no current flows from the DC power supply 40 to the excitation circuit 28, so that the heat generation of the excitation circuit 28 can be suppressed. Thereby, since it is suppressed that the electromagnetic actuator 22 becomes high temperature, the electromagnetic actuator 22 can be used even in the vacuum where the heat of the electromagnetic actuator 22 is difficult to radiate.

  In the first embodiment, as described above, the electromagnetic actuator 22 is formed into a flat linear motor including flat surface excitation coils 27a to 27c and permanent magnets 29a to 29f, so that the thickness is reduced. Therefore, when used in a vacuum, a passage having a small height (opening of the gate valve 12 (12a)) for accessing the inside of the vacuum processing apparatus 200 can be passed.

(Modification of the first embodiment)
Next, a modification of the first embodiment of the present invention will be described with reference to FIG. In the modification of the first embodiment, in the first embodiment configured to reduce the moving speed when shifting to the clamp state by the thrust of the electromagnetic actuator 22, the wafer clamp is further performed by the thrust of the electromagnetic actuator. An example of assisting force will be described.

  As shown in FIG. 11, the exciting circuit 128 of the electromagnetic gripper 101 according to the modification of the first embodiment of the present invention is applied to the exciting coils 27 a to 27 c in the forward direction (arrow A direction) and the reverse direction (arrow B direction). A variable power supply 40a that can switch the direction of the current supplied to the power supply is included. The remaining configuration of the modification of the first embodiment is the same as that of the first embodiment.

  Next, the operation of the excitation circuit 128 of the electromagnetic gripper 101 according to the modification of the first embodiment will be described.

  First, as in the first embodiment described above, when the excitation circuit 128 changes from the on-state to the off-state when shifting from the clamp-released state to the clamped state, the current stored in the capacitor 35 is supplied. By causing the actuator 22 to generate a thrust force in the direction of the arrow X2 that reduces the urging force of the spring member 30 in the direction of the arrow X1, the movable portion 25 moves in a state where the speed is reduced in the direction of the arrow X1. Then, the movable claw 26 of the movable unit 25 slowly comes into contact with the wafer 9 at a small speed and presses the wafer 9 against the fixed claw 20 to be in a clamped state. Here, in the modification of the first embodiment, as shown in FIG. 11, the electromagnetic actuator 22 causes a current to flow in the excitation circuit 128 in the opposite direction (arrow B direction) to the excitation circuit 128 in the clamped state. Thus, thrust in the direction (arrow X1 direction) that assists the clamping force of the movable portion 25 by the biasing force of the spring member 30 is generated. That is, by switching the direction of the current supplied to the excitation circuit 128 from the forward direction (arrow A direction) to the reverse direction (arrow B direction) while the wafer 9 is clamped, the thrust from the electromagnetic actuator 22 in the arrow X1 direction. Occurs. Thereby, it is possible to assist (complement) the urging force (clamping force) acting toward the arrow X1 direction of the spring member 30 with the thrust acting from the electromagnetic actuator 22 toward the arrow X1 direction. Note that other operations of the modified example of the first embodiment are the same as those of the first embodiment.

  In the modification of the first embodiment, as described above, thrust in a direction that assists the clamping force of the movable portion 25 by the biasing force of the spring member 30 by flowing a current in the reverse direction through the excitation circuit 28 in the clamped state. When the biasing force of the spring member 30 is weak and the wafer 9 cannot be clamped sufficiently, the thrust of the electromagnetic actuator 22 can be supplemented with the biasing force of the spring member 30 as a clamping force. The wafer 9 can be securely clamped.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, unlike the first embodiment in which an excitation circuit including a capacitor is applied to an electromagnetic actuator, an example in which an excitation circuit including a diode is applied to the electromagnetic actuator will be described.

  The exciting circuit 28a of the electromagnetic gripper 102 according to the second embodiment includes exciting coils 27a to 27c, a DC power supply 40, a bypass circuit 281a, and a switch unit 41. The bypass circuit 281a includes one diode 281b. The bypass circuit 281a is provided to flow a current due to a counter electromotive force generated when the excitation circuit 28a is turned off without flowing a current when the excitation circuit 28a is turned on. The + terminal of the DC power supply 40 is connected to one end of the exciting coil 27a and one end of the bypass circuit 281a. The other end of the exciting coil 27a is connected to one end of the exciting coil 27b, and the other end of the exciting coil 27b is connected to one end of the exciting coil 27c. The other end of the exciting coil 27 c and the other end of the bypass circuit 281 a are connected to one end of the switch unit 41. The other end of the switch unit 41 is connected to the negative terminal of the DC power supply 40. In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  Next, the operation of the electromagnetic gripper 102 will be described with reference to FIGS. 4, 10, 12 and 13.

  First, when the clamped state of the wafer 9 is released, as shown in FIG. 12, the switch unit 41 is turned on (the excitation circuit 28a is turned on), and the excitation coil 27a to 27c is switched from the + terminal side of the DC power supply 40. Current is supplied. At this time, no current flows through the bypass circuit 281a due to the rectification action of the diode 281b. In addition, the movable portion 25 is urged in the direction of the arrow X1 of the spring member 30 by the thrust (electromagnetic force) generated between the current flowing through the excitation coils 27a to 27c and the magnetic field generated from the permanent magnets 29a to 29f. It moves in the direction of arrow X2 so as to overcome. And when the movable part 25 contact | abuts to the stopper 34b of the arrow X2 direction side, while the movement of the movable part 25 stops, it will be in a clamp release state (refer FIG. 4).

  Next, when shifting from the clamp release state to the clamp state, the switch unit 41 is turned off (the excitation circuit 28a is turned off), and the current supply from the DC power supply 40 to the excitation coils 27a to 27c is stopped. Here, in the second embodiment, as shown in FIG. 13, the excitation circuit 28 a of the electromagnetic actuator 22 shifts from a clamp release state (a state where the wafer 9 is not clamped) to a clamp state (a state where the wafer 9 is clamped). When the excitation circuit 28a is switched from the ON state to the OFF state, a current caused by a back electromotive force transiently generated in the excitation coils 27a to 27c is caused to flow through the bypass circuit 281a, whereby the current flowing through the excitation circuit 28a is changed. Decrease gradually.

  That is, when shifting from the clamp release state to the clamp state, the switch unit 41 is turned off (the excitation circuit 28a is turned off), and current supply from the DC power supply 40 to the excitation coils 27a to 27c is stopped. At this time, back electromotive force is generated in the excitation coils 27a to 27c of the fixed portion 23, and current flows to the excitation coils 27a to 27c via the diode 281b of the bypass circuit 281a. Thereby, between the electric current which flows into excitation coil 27a-27c, and the magnetic field which generate | occur | produces from permanent magnet 29a-29f (refer FIG. 4), it is a direction (arrow) opposite to the urging | biasing force smaller than the urging | biasing force of the spring member 30. X2 direction) thrust (electromagnetic force) is generated. Due to the thrust (electromagnetic force) in the arrow X2 direction, a part of the urging force in the arrow X1 direction by the spring member 30 acting on the movable portion 25 is canceled and reduced, so that the moving speed of the movable portion 25 is reduced. The moving claw 26 is slowly moved in the direction of the arrow X1 in the state of being in contact with the wafer 9 at a low speed. The thrust generated in the direction of the arrow X2 gradually decreases as the current flowing through the exciting coils 27a to 27c decreases, so that the spring member 30 acting on the wafer 9 via the movable claw 26 is attached in the direction of the arrow X1. The force (pressing force) gradually increases. As the urging force of the spring member 30 in the arrow X1 direction acting on the wafer 9 increases, the wafer 9 starts moving in the arrow X1 direction and comes into contact with the fixed claw 20. Thereafter, when the back electromotive force is not generated, the thrust is not generated, and only the urging force of the spring member 30 acts on the wafer 9 to be in a clamped state. Thereafter, as shown in FIG. 10, the clamped wafer 9 passes through the gate valve 12 (12a) having a small height of the vacuum processing apparatus 200, or the vacuum processing units 1 to 4 or the load lock chambers 6 and 7 are placed. To be transported.

  In the second embodiment, as described above, when the excitation circuit 28a is switched from the on state to the off state, a current caused by the counter electromotive force transiently generated in the excitation coils 27a to 27c is caused to flow through the bypass circuit 281a. Thus, when the excitation circuit 28a is turned from the on state to the off state by gradually decreasing the current flowing through the excitation circuit 28a, the excitation coils 27a to 27c are moved by the current due to the back electromotive force that is transiently generated. Since the thrust is generated in the direction of reducing the moving speed of the moving part 25, the moving part 25 can gradually approach the wafer 9 while reducing the moving speed of the moving part 25.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, an example in which three excitation coils 27a to 27c of the excitation circuit are connected in parallel will be described, unlike the first embodiment in which the three excitation coils 27a to 27c of the excitation circuit are connected in series.

  The exciting circuit 28b of the electromagnetic gripper 103 according to the third embodiment of the present invention includes three exciting coils 27a, 27b and 27c connected in parallel, and a direct current for supplying a direct current to the three exciting coils 27a, 27b and 27c. The power supply 40 and three switch parts 41a, 41b and 41c are included.

  In addition, one end of each of the exciting coils 27 a to 27 c is connected to the + terminal of the DC power supply 40. Further, one ends of the switch portions 41a to 41c are connected to the other ends of the exciting coils 27a to 27c, respectively. Further, the other ends of the switch units 41 a to 41 c are connected to the other end of the DC power supply 40. The switch units 41a to 41c are configured to control the on / off operation of the exciting coils 27a to 27c, respectively. Further, since the excitation coils 27a to 27c are configured to be able to supply currents separately, it is possible to generate thrust separately for the excitation coils 27a to 27c.

  Next, the operation of the electromagnetic gripper 103 will be described with reference to FIGS. 4 and 14 to 17.

  First, when the clamped state of the wafer 9 is released, as shown in FIG. 14, the three switch parts 41a to 41c are turned on (the exciting circuit 28b is turned on), and the three exciting coils 27a are supplied from the DC power supply 40. Current is supplied to .about.27c. At this time, the movable portion 25 urges the spring member 30 in the direction of the arrow X1 by the thrust (electromagnetic force) generated between the current flowing through the excitation coils 27a to 27c and the magnetic field generated from the permanent magnets 29a to 29f. And move in the direction of the arrow X2. And when the movable part 25 contact | abuts to the stopper 34b of the arrow X2 direction side, while the movement of the movable part 25 stops, it will be in a clamp release state (refer FIG. 4).

  Next, when shifting from the clamp release state to the clamp state, in the third embodiment, as shown in FIGS. 15 to 17, the switch units 41 a to 41 c are controlled so that the excitation coils 27 a to 27 c are sequentially turned off. As a result, the current flowing through the excitation circuit 28b is gradually reduced. At this time, the switch units 41a to 41c are turned off one by one with a predetermined time difference. The time difference (the energization time of the exciting coils 27a to 27c at each stage when the number of exciting coils 27a to 27c through which current flows) is reduced can be arbitrarily adjusted (controlled).

  That is, when the wafer 9 is shifted from the clamp released state to the clamped state, as shown in FIG. 15, first, the switch portion 41a is turned off, and the current supply from the DC power supply 40 to the exciting coil 27a is stopped. At this time, thrust (electromagnetic force) between the exciting coil 27a and the magnetic field generated from the permanent magnets 29a and 29b corresponding to the exciting coil 27a is not generated. Thereby, the movable part 25 moves to the arrow X1 direction to the position where the urging | biasing force of the spring member 30 and a thrust balance with the urging | biasing force of the arrow X1 direction of the spring member 30. FIG. When one exciting coil is turned off and the urging force of the spring member 30 is large, the movable portion 25 starts to move in the direction of the arrow X1, but is attached in accordance with the extension of the spring member 30. Since the power also becomes weak, the moving operation of the movable portion 25 stops or the speed becomes slow.

  Next, as shown in FIG. 16, the switch unit 41b is also turned off, and the current supply from the DC power supply 40 to the exciting coil 27b is stopped. At this time, thrust (electromagnetic force) between the exciting coil 27b and the magnetic field generated from the permanent magnets 29c and 29d corresponding to the exciting coil 27b is not generated. Accordingly, the movable portion 25 is further moved in the arrow X1 direction by the biasing force of the spring member 30 in the arrow X1 direction, and the movable claw 26 of the movable portion 25 contacts the wafer 9. At this time, the difference between the urging force of the spring member 30 and the thrust in the arrow X2 direction becomes a force (pressing force) for pressing the wafer 9 in the arrow X2 direction.

  Finally, as shown in FIG. 17, the switch unit 41c is turned off, and the current supply from the DC power supply 40 to the exciting coil 27c is stopped. That is, all the three switch parts 41a-41c will be in an OFF state. At this time, thrust (electromagnetic force) between the exciting coil 27c and the magnetic field generated from the permanent magnets 29e and 29f corresponding to the exciting coil 27c is not generated. As a result, the wafer 9 starts moving in the direction of the arrow X1 as the biasing force of the spring member 30 in the direction of the arrow X1 acting on the wafer 9 increases, and comes into contact with the fixed claw 20. Thereafter, only the urging force of the spring member 30 acts on the wafer 9 to be in a clamped state. Note that the movable claw 26 of the movable unit 25 may be in contact with the wafer 9 when one switch unit 41a or the two switch units 41a and 41b are turned off. Thus, by sequentially turning off the switch portions 41a to 41c (stepwise), the movable portion 25 can be gradually moved stepwise in the arrow X1 direction. As shown in the modification of the first embodiment, the DC power source 40 is replaced with the variable power source 40a, and a current in the reverse direction is supplied to the exciting coils 27a to 27c when the wafer 9 is clamped. It is also possible to assist the clamping force at the time of clamping.

  In the third embodiment, as described above, when the excitation circuit 28b is changed from the on state to the off state, the excitation circuits 27a to 27c are sequentially turned off so as to sequentially turn off the three switch units 41a to 41c. By gradually decreasing the current flowing through 28b, the number of exciting coils 27a-27c through which current flows stepwise can be reduced by sequentially turning off the three switch portions 41a-41c. The movable part 25 can be brought close to the wafer 9. In addition, it is possible to more appropriately control the energization time of the excitation coils 27a to 27c at each stage when the excitation coils 27a to 27c are sequentially turned off to reduce the number of excitation coils 27a to 27c through which current flows. The degree of reduction in the moving speed of the movable portion 25 can be controlled.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, unlike the first embodiment in which the DC power source and the switch unit are configured to excite the electromagnetic actuator, the current control circuit 50 controls the current when the excitation is turned off in order to excite the electromagnetic actuator. An example in which the current flowing through the exciting coil is gradually turned off will be described.

  The exciting circuit 28c of the electromagnetic gripper 104 according to the fourth embodiment includes exciting coils 27a to 27c and a current control circuit 50. The other end of the excitation coil 27a is connected to one end of the excitation coil 27b, and the other end of the excitation coil 27b is connected to one end of the excitation coil 27c. A current control circuit 50 is provided between one end of the excitation coil 27a and the other end of the excitation coil 27c, and the current control circuit 50 controls the amount of excitation current of the excitation coils 27a to 27c. . The current control circuit 50 operates under microcomputer control, and outputs a desired current pattern by receiving an excitation circuit on / off signal by a built-in program. In addition, the other structure of 4th Embodiment is the same as that of the said 1st Embodiment.

  Next, the operation of the electromagnetic gripper 104 will be described with reference to FIGS. 4, 10, 18 and 19.

  First, when the clamped state of the wafer 9 is released, a predetermined current flows in the arrow direction (clockwise direction) from the current control circuit 50 by receiving the excitation-on signal in FIG. 18, and the current flows in the excitation coils 27a to 27c. Is supplied. Due to the thrust (electromagnetic force) generated between the current flowing through the exciting coils 27a to 27c and the magnetic field generated from the permanent magnets 29a to 29f (see FIG. 4), the movable portion 25 is moved in the direction of the arrow X1 of the spring member 30. It moves in the direction of the arrow X2 so as to overcome the urging force. And when the movable part 25 contact | abuts to the stopper 34b of the arrow X2 direction side, while the movement of the movable part 25 stops, it will be in a clamp release state (refer FIG. 4).

  Next, when shifting from the clamp release state to the clamp state, the current control circuit 50 stops the current supply to the excitation coils 27a to 27c by receiving the excitation off signal. Here, in the fourth embodiment, the current supply from the current control circuit 50 is not stopped immediately (instantly), but the excitation current gradually decreases with time as shown in FIG. Therefore, the current control circuit 50 is configured in advance.

  That is, when shifting from the clamp release state to the clamp state, the current flowing through the excitation coils 27a to 27c gradually decreases, and therefore the biasing force of the spring member 30 generated by the permanent magnets 29a to 29f (see FIG. 4) is reduced. The opposing force in the direction of arrow X2 gradually weakens. Therefore, the movable portion 25 moves slowly in the direction of the arrow X1 with the movement speed reduced, and the movable claw 26 slowly contacts the wafer 9 at a low speed. When the exciting current disappears, no thrust is generated, and only the urging force of the spring member 30 acts on the wafer 9 to enter a clamped state. Thereafter, as shown in FIG. 10, the clamped wafer 9 passes through the gate valve 12 (12a) having a small height of the vacuum processing apparatus 200, or the vacuum processing units 1 to 4 or the load lock chambers 6 and 7 are placed. To be transported.

  In the fourth embodiment, as described above, the force against the biasing force of the spring member 30 is gradually reduced by gradually reducing the excitation current by using the current control circuit 50 when the excitation current is off. Can do. Thereby, since the moving speed of the movable part 25 can be reduced, the movable part 25 can be gradually approached to the wafer 9.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to fourth embodiments, the semiconductor wafer is shown as an example of the thin plate-like material of the present invention, but the present invention is not limited to this. For example, as long as it is a thin plate, other thin plate such as a glass substrate other than a semiconductor wafer can be applied.

  Moreover, although the example which uses an electromagnetic gripper in a multi-chamber type vacuum processing apparatus was shown in the said 1st-4th embodiment, this invention is not limited to this. For example, you may use in the processing apparatus which uses an electromagnetic gripper under atmospheric pressure.

  In the first to fourth embodiments, an example in which a capacitor, a diode, or a switch unit is provided in the excitation circuit has been described. However, the present invention is not limited to this. In the present invention, when the electromagnetic actuator shifts from the clamp release state to the clamp state, an excitation circuit can be used as long as it generates thrust in a direction that reduces the moving speed of the movable part due to the biasing force of the spring member in the clamp direction. An element or a circuit other than a capacitor, a diode, or a switch unit may be provided in the circuit.

  Moreover, although the said 1st-4th embodiment showed the example comprised so that urging | biasing force might generate | occur | produce using two spring members, this invention is not limited to this. For example, the biasing force may be generated using one or three or more spring members.

  Moreover, although the example which comprises a fixing | fixed part with three exciting coils was shown in the said 1st-4th embodiment, this invention is not limited to this. For example, you may comprise a fixing | fixed part with two or less or four or more exciting coils.

9 Wafer (thin plate)
22 Electromagnetic actuator 24 Clamping part 25 Movable part 27a, 27b, 27c Excitation coil 28, 28a, 28b, 28c, 128 Excitation circuit 30 Spring member 35 Capacitor 41a, 41b, 41c Switch part 100, 101, 102, 103, 104 Electromagnetic gripper (Gripping device)
281a Bypass circuit 281b Diode

Claims (7)

A clamp part including a movable part that moves in the direction of clamping the thin plate-like object;
A spring member that constantly urges the movable part of the clamp part in a clamping direction;
An electromagnetic actuator that generates a thrust when shifting from the clamp release state to the clamp state,
Wherein the electromagnetic actuator, when moving from the unclamping state to the clamping state, the spring member in a direction to the excitation of the flat surface shape that generates a thrust to reduce the moving speed of the movable portion by the urging force of the clamping direction a coil, the excitation circuit and a permanent magnet provided so as to face the flat surface shape of the exciting coil is configured including flat,
The spring member includes a first spring member and a second spring member provided on both sides of the flat electromagnetic actuator,
In the electromagnetic actuator, when the excitation circuit is changed from the ON state to the OFF state when the clamp circuit is shifted from the clamp release state to the clamp state, the thrust of the electromagnetic actuator gradually decreases as the spring member extends. The current flowing through the excitation circuit is gradually reduced so as to be smaller than the force, and is configured to generate a thrust in a direction to reduce the moving speed of the movable part due to the biasing force of the spring member. Gripping device. The excitation circuit includes a capacitor for storing the current of the excitation circuit,
2. The grip according to claim 1, wherein when the excitation circuit is switched from an on state to an off state, the current flowing through the excitation circuit is gradually decreased by flowing a current stored in the capacitor. apparatus. The excitation circuit includes a bypass circuit including a diode for causing a current to flow when a counter electromotive force is generated when the current is not flown when the switch is turned on,
When the excitation circuit is switched from an on state to an off state, a current caused by a back electromotive force generated transiently in the excitation coil is caused to flow through the bypass circuit, whereby the current flowing through the excitation circuit gradually decreases. The gripping device according to claim 1, configured as described above. The excitation circuit includes a plurality of the excitation coils, and a plurality of switch units that are provided so as to correspond to the plurality of excitation coils, and that control on / off operations of the plurality of excitation coils,
When switching the excitation circuit from the on state to the off state, the plurality of excitation coils are sequentially turned off to control the plurality of switch units so that the current flowing through the excitation circuit gradually decreases. The gripping device according to claim 1. The clamp part and the electromagnetic actuator are used in a vacuum,
The electromagnetic actuator is configured to generate thrust in the clamp release state in addition to the transition from the clamp release state to the clamp state,
In the clamp release state, the excitation circuit is turned on and a current flows, whereby a thrust in a direction against the urging force of the spring member is generated in the electromagnetic actuator, and the movable part is opposite to the clamp direction. In the clamped state, the exciting circuit is turned off and no current flows, so that no thrust is generated in the electromagnetic actuator and the movable part is clamped by the biasing force of the spring member. The gripping device according to any one of claims 1 to 4, wherein the gripping device is configured to be clamped by being biased. The excitation circuit of the electromagnetic actuator is configured to be able to change the direction of the flowing current,
In the clamped state, by causing a current to flow in a direction opposite to that when the excitation circuit is turned on, the electromagnetic actuator is caused to generate a thrust force in a direction that assists the clamping force of the movable part by the biasing force of the spring member. The gripping device according to any one of claims 1 to 5, wherein the gripping device is configured.   The gripping apparatus according to claim 1, wherein the electromagnetic actuator includes a flat linear motor.

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