JP2007129137A - Substrate transfer apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate transfer apparatus which prevents excessive restraints on a second arm, while smoothly carrying out the passage of arms over a dead point. <P>SOLUTION: The substrate transfer apparatus 10 is provided with a dead point escaping mechanism 15 which gives a torque to the second arm 21, only when the first and second arms 11 and 21 pass the dead point, at which both arms becomes parallel with each other. The dead point escaping mechanism 15 includes a fixing gear 16 disposed around a rotating shaft 1 rotating the first arm 11, a first rotating gear 17 engaged with the fixing gear 16, a second gear 18 to which the torque of the first rotating gear 17 is transmitted via a link 19, and an engaging gear 20 which engages with the second gear 18, only when the second arm 21 passes the dead point to give an axial torque to the second arm 21. This structure allows the substrate transfer apparatus 10 to prevent excessive restraints on the second arm 21, while smoothly carrying out the passage of the arms 11 and 21 over the dead point, which leads to improvement in the stable rectilinear motion of a substrate and transfer precision. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate transfer apparatus for transferring, for example, a semiconductor substrate or the like into a vacuum processing chamber and transferring it to a predetermined position.

  In recent years, there has been a demand for ultra-miniaturization and high precision for semiconductor elements. In an apparatus for manufacturing such semiconductor elements, the throughput is improved, the floor area for installing the apparatus is reduced, etc. Is required.

  For this reason, in a multi-chamber apparatus in which a plurality of processing chambers are arranged around a transfer chamber and connected through gate valves, various substrate processes can be performed consistently in vacuum. A substrate transfer device for automatically loading / unloading a substrate from / to each processing chamber is used.

  As the substrate transfer device, an arm type or a frog-leg type is known. For example, a frog-leg type substrate transfer device is configured as schematically shown in FIG. The frog-leg type substrate transfer apparatus includes a base 3 having a pair of rotating shafts 1 and 2 rotating in different directions, and a pair of first arms 11 having the rotating shafts 1 and 2 connected to one end of each. , 12 and a pair of second arms 21 and 22 having one end rotatably coupled to the other end of each of the first arms 11 and 12, and rotatable to the other end of each of the second arms 21 and 22 And a substrate support 4 coupled to the substrate.

  The first arms 11 and 12 and the second arms 21 and 22 have the same arm length, and a parallel link mechanism is constituted by these. Accordingly, by rotating the pivot shafts 1 and 2 in opposite directions, the angle θ formed by the first arms 11 and 12 and the second arms 21 and 22 changes, and the substrate support 4 is moved in the vertical direction in the figure. Moved. Thereby, the substrate W on the substrate support 4 can be transported to an arbitrary position. Note that the substrate support 4 is pivoted around the base 3 by rotating the base 3 around its axis. Further, a drive motor (drive source) is connected to one of the rotating shafts 1 and 2.

  In the frog-leg type substrate transport apparatus having such a configuration, when the substrate W is transported with respect to the base 3 from the front position shown in FIG. 6A to the rear position shown in FIG. 6B, the pair of first arms 11 and 12 and It is necessary to pass through the position shown in FIG. 6C where the pair of second arms 21 and 22 are parallel to each other (θ = 0 °). The arm position shown in FIG. 6C corresponds to the dead point of the parallel link mechanism. Therefore, in the conventional substrate transport apparatus, in order to smoothly transport the substrate W, a mechanism for applying a driving force in the moving direction to the second arms 21 and 22 at this dead center position (hereinafter referred to as “dead center escape mechanism”). ") Is provided.

  FIG. 7 shows a configuration of a conventional substrate transfer device 5 provided with a dead center escape mechanism (see Patent Document 1 below). In the figure, parts corresponding to those in FIG. The rotating shafts 1 and 2 are arranged coaxially with each other and have independent drive sources, and the substrate support 4 is configured to support two substrates W simultaneously.

  The conventional substrate transfer device 5 shown in the figure includes a first pulley 6 concentrically fixed to the rotation shaft 2 and a second pulley concentrically fixed to a connecting portion between the first arm 11 and the second arm 21. 7 and a belt 8 laid between the first pulley 6 and the second pulley 7. With this configuration, the rotational force of the rotating shaft 2 is directly transmitted to the second arm 21 via the belt 8, so that the link can pass smoothly through the dead center position.

JP-A-9-283588

  However, in the substrate transfer apparatus 5 having the conventional dead center escape mechanism shown in FIG. 7, the second arm 21 is configured to be constantly given a rotational force from the rotary shaft 2, so There is a problem in that the rotation angle is always restrained by the rotation shaft 2, and this causes a deterioration of the substrate transport accuracy.

  That is, since the second arm 21 rotates in conjunction with the rotational movement of the first arm 11, the rotation amount of the rotation shaft 2 is added to the rotation angle of the first arm 11 in the process of transporting the substrate W. By being transmitted directly, the second arm 21 is over-constrained, which may cause vibration during substrate transportation or impair the straightness of the substrate.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a substrate transfer apparatus that can prevent over-constraint of the second arm while smoothly passing through the dead center.

  In solving the above-described problems, the substrate transfer apparatus of the present invention includes a pair of rotating shafts connected to at least one drive source, and a pair of first arms connected at one end to the pair of rotating shafts. A pair of second arms having one end rotatably coupled to the other end of each of the pair of first arms and having the same arm length as the first arm, and rotating to the other end of each of the pair of second arms In a substrate transfer apparatus including a substrate support that is coupled to each other, a rotational force is applied to the second arm only when the first arm and the second arm pass through a dead center position that is parallel to each other. Has a dead center escape mechanism.

  Since the substrate transfer apparatus of the present invention includes a dead center escape mechanism that applies a rotational force to the second arm only when the first arm and the second arm pass through a dead center position that is parallel to each other. Further, it is possible to prevent the second arm from being over-constrained while smoothly passing through the dead center, and to improve the straight straightness and the conveyance accuracy of the substrate.

  Further, in the substrate transport apparatus of the present invention, the dead center escape mechanism is provided on the rotation drive unit communicating with the rotation shaft and the second arm or the substrate support, and when the substrate support passes the dead center position. It has an engaging part engaged with a rotation drive part. With this configuration, an intended rotational force can be applied to the second arm only when the second arm passes through a dead center position parallel to the first arm.

  As an example of the configuration of the dead center escape mechanism, the rotation driving unit includes a fixed gear that is installed concentrically with the rotation shaft, and a first rotation that is supported near one end of the first arm and meshes with the fixed gear. A gear, a second rotating gear that is pivotally supported in the vicinity of the other end of the first arm, and a torque transmitting member that transmits the torque of the first rotating gear to the second rotating gear. The engagement arm is fixed to the coupling shaft of the first arm and the second arm, and has engagement teeth that are partially engageable with the second rotation gear.

  As another configuration example of the dead center escape mechanism, the rotation drive unit includes a drive shaft conversion unit that converts the rotation axis of the rotation shaft into a direction orthogonal thereto, and a converted rotation axis. The engaging portion is a flat gear which is provided on the lower surface of the substrate support and can be engaged with the rotating gear.

  As described above, the substrate transfer apparatus according to the present invention provides a dead center escape that applies a rotational force to the second arm only when the first arm and the second arm pass through a dead center position that is parallel to each other. Since the mechanism is provided, it is possible to prevent the second arm from being over-constrained while smoothly passing through the dead center, and to improve the straight straightness of the substrate and the conveyance accuracy.

  Embodiments of the present invention will be described below with reference to the drawings. Although not shown, the substrate transfer apparatus of the present embodiment is a multi-chamber apparatus in which a plurality of vacuum processing chambers are arranged around a vacuum transfer chamber, and is installed in the vacuum transfer chamber and includes a plurality of load / unload chambers. This is applied to a substrate transfer apparatus for automatically transferring a substrate between the vacuum processing chambers.

[First Embodiment]
FIG. 1 shows the configuration of a substrate transfer apparatus 10 according to a first embodiment of the present invention.

  The substrate transfer apparatus 10 according to the present embodiment includes a base 3 having a pair of rotating shafts 1 and 2 rotating in different directions, and a pair of first arms each having the rotating shafts 1 and 2 connected to one end. 11 and 12, a pair of second arms 21 and 22 whose one ends are rotatably coupled to the other ends of the first arms 11 and 12 via arm coupling shafts 13 and 14, and the second arms 21. , 22 is provided with a substrate support 4 rotatably coupled to the other end.

  The first arms 11 and 12 and the second arms 21 and 22 have the same arm length, and a parallel link mechanism is constituted by these. Accordingly, by rotating the pivot shafts 1 and 2 in opposite directions, the angle θ formed by the first arms 11 and 12 and the second arms 21 and 22 changes, and the substrate support 4 is moved in the vertical direction in the figure. Moved. Thereby, the substrate W on the substrate support 4 can be transported to an arbitrary position. Note that the substrate support 4 is pivoted about the base 3 by rotating the base 3 about its axis. Further, a drive source (not shown) such as a drive motor is connected to one of the rotating shafts 1 and 2.

  Here, the rotating shafts 1 and 2 may be arranged on the same axis. In this case, as shown in FIG. 7, for example, one rotating shaft 1 is disposed on the inner peripheral side, and the other rotating shaft 2 is disposed on the outer peripheral side. Each of these rotating shafts 1 and 2 has an independent drive source, and the substrate support 4 is moved in the front-rear direction by rotating in opposite directions, and the substrate support 4 is rotated in the same direction. It will turn.

  Moreover, although the board | substrate support body 4 is set as the structure which can mount the one board | substrate W in the example of a figure, as shown in FIG. 7, it is good also as a structure which can mount two board | substrates. Further, the shape of the substrate support 4 is not limited to the example shown in the figure, and can be appropriately changed to a fork shape. As the substrate W, an unprocessed or already processed semiconductor wafer substrate, glass substrate, or the like is applied.

  In such a frog-leg type substrate transport apparatus 10, when the substrate W is transported with respect to the base 3 from the front position (upper position in the figure) to the rear position (lower position in the figure), a pair of first It is necessary that the arms 11 and 12 and the pair of second arms 21 and 22 pass through a dead center position where they are parallel to each other (θ = 0 °). Therefore, in order to smoothly pass through the dead center position, the substrate transport apparatus 10 of the present embodiment is provided with a dead center escape mechanism 15 described later.

  2 and 3 show the configuration of the dead center escape mechanism 15. Here, FIG. 2 is a fragmentary side view of the principal part of the substrate transport apparatus 10, and FIG. 3 is a principal part plan view for explaining the operation of the dead center escape mechanism 15.

  In the present embodiment, the dead center escape mechanism 15 is attached to the second arm 21 only when the pair of first arms 11 and 12 and the pair of second arms 21 and 22 pass through a dead center position that is parallel to each other. It is comprised so that rotational force may be provided with respect to it. The dead center escape mechanism 15 is provided on the first arm 11 and the second arm 21 on one side, respectively, but may be provided on the first arm 12 and the second arm 22 on the other side.

  A fixed gear 16 is installed on the base 3 concentrically with the rotating shaft 1 that rotates the first arm 11. A first rotating gear 17 that meshes with the periphery of the fixed gear 16 is rotatably supported near one end on the lower surface side of the first arm 11. The first rotating gear 21 rotates while circling around the fixed gear 16 like a planetary gear as the first arm 11 rotates. Near the other end on the lower surface side of the first arm 11, a second rotating gear 18 is rotatably supported. A link (lever) 19 is connected between the second rotation gear 18 and the first rotation gear 17, and the rotational force of the first rotation gear 17 is transmitted to the second rotation gear 18 via the link 19. It is comprised so that.

  The fixed gear 16, the first rotating gear 17, the second rotating gear 18 and the link 19 constitute a “rotation drive unit” according to the present invention. The link 19 is a specific example of the “rotational force transmission member” of the present invention, and may be constituted by a belt member other than the link, for example.

  On the other hand, at the lower end of the arm coupling shaft 13 that couples the other end of the first arm 11 and one end of the second arm 21, the second rotation gear is rotated when the second arm 21 is at a predetermined rotation angle (rotation phase). An engagement gear 20 that engages with the shaft 18 is fixed. The arm coupling shaft 13 is fixed to the second arm 21 and rotates relative to the first arm 11. The engagement gear 20 corresponds to an “engagement portion” according to the present invention, and has an engagement tooth 20 a that can be engaged with the second rotation gear 18 partially on the outer peripheral portion. The engaging teeth 20a are arranged in the extending direction of the second arm 21, and as shown in FIG. 3B, a dead center position where the second arm 21 overlaps and is parallel to the first arm 11, and a predetermined position before and after the dead center position. Only in the angular range, the second rotating gear 18 is engaged.

  In the substrate transport apparatus 10 of the present embodiment configured as described above, the pair of first arms 11 and 12 and the pair coupled thereto are rotated by rotating the rotation shafts 1 and 2 in opposite directions. The parallel link mechanism composed of the second arms 21 and 22 expands and contracts, and the substrate W on the substrate support 4 is linearly transferred in the front-rear direction (vertical direction in FIG. 1). More specifically, the substrate W advances in the F direction in FIG. 1 by rotating one rotating shaft 1 counterclockwise and rotating the other rotating shaft 2 clockwise. Further, the substrate W moves backward in the direction B in FIG. 1 as one pivot shaft 1 rotates clockwise and the other pivot shaft 2 rotates counterclockwise.

  In the dead center escape mechanism 15, as the first arm 11 rotates, the first rotating gear 17 meshing with the fixed gear 16 rotates as shown in FIG. It is transmitted to the rotating gear 18. When the substrate support 4 is linearly moved at the front position with respect to the base 3 as shown in FIG. 1, the engagement teeth 20 a of the engagement gear 20 do not engage with the second rotation gear 18. The two arms 21 rotate at a rotation angle corresponding to the rotation angle of the first arm 11 without receiving any restraining force from the rotation shaft 1.

  On the other hand, when the substrate support 4 is transported from the front position shown in FIG. 1 to the rear position of the base 3 with respect to the base 3, the pair of second arms 21 and 22 are parallel to the first arms 11 and 12, respectively. Will pass the dead center position of the link. In this case, the engagement gear 20 engages with the second rotation gear 18 that rotates as the first arm 11 rotates (FIG. 3B). Thereby, the second arm 21 receives a predetermined axial torque in the rotation direction of the second rotation gear 18 via the engagement gear 20 and can smoothly pass the dead center position shown in FIG. 3B ( FIG. 3C).

  Note that the same operation as described above is performed when the substrate support 4 is moved from the rear position to the front position of the base 3. In this case, the rotation direction of the second rotation gear 18 is opposite to the above.

  Therefore, according to the substrate transfer apparatus 10 of the present embodiment, the second arm only when the pair of first arms 11 and 12 and the pair of second arms 21 and 22 pass through a dead center position that is parallel to each other. Since the dead center escape mechanism 15 for applying a rotational force to the motor 21 is provided, the second arm 21 is prevented from being over-restrained when the dead center is not passed while the dead center is passed smoothly, thereby stabilizing the substrate W. It is possible to improve the straightness and the conveyance accuracy.

  Further, according to the substrate transfer apparatus 10 of the present embodiment, when the second arms 21 and 22 are temporarily stopped at the dead center position and the second arms 21 and 22 are moved again from the dead center position, By receiving the rotational force imparting action by the dead center escape mechanism 15, the second arms 21 and 22 can move smoothly.

[Second Embodiment]
4 and 5 show the configuration of the substrate transfer apparatus 30 according to the second embodiment of the present invention. FIG. 4 is a plan view of the substrate transfer apparatus 30 and FIG. 5 is a front view of the substrate transfer apparatus 30. . In each figure, the same reference numerals are given to portions corresponding to those in the first embodiment.

  As in the first embodiment, the substrate transfer apparatus 30 according to the present embodiment includes a base 3 having a pair of rotating shafts 1 and 2 that rotate in different directions, and rotating shafts 1 and 2. A pair of first arms 11 and 12 coupled to one end, a pair of second arms 21 and 22 coupled to the other end of each of the first arms 11 and 12, respectively, A substrate support 4 is rotatably connected to the other end of each of the two arms 21 and 22.

  The pair of first arms 11 and 12 and the pair of second arms 21 and 22 have the same arm length, and a parallel link mechanism is constituted by these. Accordingly, by rotating the pivot shafts 1 and 2 in opposite directions, the angle θ formed by the first arms 11 and 12 and the second arms 21 and 22 changes, and the substrate support 4 is moved in the vertical direction in the figure. Moved. Note that the substrate support 4 is pivoted about the base 3 by rotating the base 3 about its axis.

  In the present embodiment, gear members 33 and 34 are fixed around the coupling shafts 31 and 32 that couple the other ends of the second arms 21 and 22 and the substrate support 4, respectively. These gear members 33 and 34 are meshed with each other and can rotate in opposite directions to constitute a posture holding mechanism that holds the posture of the substrate support 4 constant during the rotation of the second arms 21 and 22. ing.

  In such a frog-leg type substrate transport apparatus 30, when the substrate support 4 is transported relative to the base 3 from the front position (upper position in the figure) to the rear position (lower position in the figure), a pair of The first arms 11 and 12 and the pair of second arms 21 and 22 need to pass through a dead center position where they are parallel to each other (θ = 0 °). Therefore, in order to smoothly pass through this dead center position, a dead center escape mechanism 35 having a configuration described below is provided in the present embodiment.

  The dead center escape mechanism 35 is a rotational force with respect to the second arms 21 and 22 only when the pair of first arms 11 and 12 and the pair of second arms 21 and 22 pass through dead center positions that are parallel to each other. Is configured to grant.

  Referring to FIG. 5, a first bevel gear 36 is provided at the upper end of the rotation shaft 2 that rotates the first arm 12. The first bevel gear 36 faces the upper surface of the first arm 12, and the second bevel gear 38 is engaged with the first bevel gear 36. The second bevel gear 38 is rotatably supported by a support column 37 erected substantially at the center of the upper surface of the base 3. The first and second bevel gears 36 and 38 constitute a drive shaft converting portion that converts the rotational axis of the rotating shaft 2 in a direction orthogonal thereto. A rotation gear 39 is integrally fixed to the shaft portion of the second bevel gear 38 and is rotated around the rotation axis converted by the drive shaft conversion portion.

  The drive shaft conversion section and the rotation gear 39 constitute a “rotation drive section” according to the present invention. In the present embodiment, a rack (flat gear) 41 provided on the lower side of the substrate support 4 is used as an engagement portion that engages with the rotation drive portion when the substrate support 4 passes through the dead center position. Is used. The rack 41 is provided on the lower surface of the support plate 40 that supports the lower ends of the coupling shafts 31 and 32. The gear length can be arbitrarily set. For example, the rotation gear 39 can be set only at a dead center position (θ = 0 °) where the second arms 21 and 22 are parallel to the first arms 11 and 12 and within a predetermined angle range before and after that. The length is engaged.

  In the substrate transport apparatus 30 of the present embodiment configured as described above, the pair of first arms 11 and 12 and the pair coupled thereto are rotated by rotating the rotation shafts 1 and 2 in opposite directions. The parallel link mechanism composed of the second arms 21 and 22 expands and contracts, and the substrate on the substrate support 4 is moved straight forward and backward.

  In the dead center escape mechanism 35, the first bevel gear 36 rotates as the first arm 12 rotates, and the rotation of the rotary shaft 2 via the second bevel gear 38 that engages with the first bevel gear 36. The axis is converted 90 ° laterally in FIG. Then, the rotation gear 39 rotates around the converted rotation axis. When the substrate support 4 is linearly moved at the front position relative to the base 3 as shown in FIG. 4, the rack 41 as the engaging portion does not engage with the rotating gear 39. 22 rotates at a rotation angle corresponding to the rotation angle of the first arms 11 and 12 without receiving any restraining force from the rotation shaft 2.

  On the other hand, when the substrate support 4 is conveyed in the arrow B direction from the front position shown in FIG. 4 to the base 3 toward the rear position of the base 3, the pair of second arms 21 and 22 are respectively It passes through the dead center position of the link parallel to one arm 11, 12. In this case, the rack 41 is engaged with the rotating gear 39 that rotates as the first arm 12 rotates. Thus, the second arms 21 and 22 receive a predetermined axial torque in the rotation direction of the rotary gear 39 via the rack 41, and can pass smoothly through the dead center position.

  Note that the same operation as described above is performed when the substrate support 4 is moved from the rear position to the front position of the base 3. In this case, the rotation direction of the rotation gear 39 is opposite to the above.

  Therefore, according to the substrate transfer apparatus 30 of the present embodiment, the second arm only when the pair of first arms 11 and 12 and the pair of second arms 21 and 22 pass through a dead center position that is parallel to each other. Since the dead center escape mechanism 35 for applying rotational force to the 21 and 22 is provided, the second arm 21 and 22 is prevented from being over-constrained when the dead center is not passed while smoothly passing the dead center. It is possible to improve the straightness of the substrate and the conveyance accuracy.

  Further, according to the substrate transport apparatus 30 of the present embodiment, the second arms 21 and 22 are temporarily stopped at the dead center position, and when the second arms 21 and 22 are moved again from the dead center position, By receiving the rotational force imparting action by the dead center escape mechanism 35, the second arms 21 and 22 can move smoothly.

  As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to these, A various deformation | transformation is possible based on the technical idea of this invention.

  For example, in the first embodiment described above, in the engaging gear 20 constituting the dead center escape mechanism 15, the second position is only passed when passing through the dead center position of the link where the substrate support 4 is located immediately above the base 3. The engaging teeth 20a are formed only at a rotation angle that can be engaged with the rotating gear 18, but by forming the engaging teeth 20a at a position further 180 ° apart from the outer periphery of the engaging gear 20, θ = 180 °. The drive control at the arm position (or dead point position) at (or -180 °) can also be performed stably and with high accuracy.

  In each of the above embodiments, the dead center escape mechanisms 15 and 35 are configured using a gear driving force transmission mechanism. Instead, for example, a rotary motor is provided on the arm coupling shaft 13 (or 14). It is good also as a structure which provides axial torque only when installing and passing a dead center position.

  Further, the present invention is not limited to the application example to the substrate transfer apparatus used in a vacuum atmosphere such as a vacuum transfer chamber, but can be applied to the substrate transfer apparatus used in the air.

1 is a schematic plan view of a substrate transfer apparatus 10 according to a first embodiment of the present invention. FIG. 3 is a cutaway side view of a main part of the substrate transfer apparatus 10. FIG. 6 is a plan view of a principal part for explaining the operation of a dead center escape mechanism of the substrate transport apparatus 10. It is a schematic plan view of the board | substrate conveyance apparatus 30 by the 2nd Embodiment of this invention. 3 is a front view of a substrate transfer device 30. FIG. It is a figure explaining the conventional frog-leg type board | substrate conveyance apparatus. It is a schematic plan view of the board | substrate conveyance apparatus provided with the conventional dead center escape mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Rotating shafts 10, 30 Substrate conveyance device 11, 12 1st arm 13, 14 Arm coupling shaft 15 Dead center escape mechanism 16 Fixed gear 17 1st rotating gear 18 2nd rotating gear 19 Link (rotational force transmission member)
20 Engagement gear (engagement part)
21, 22 Second arm 31, 32 Coupling shaft 35 Dead center escape mechanism 36, 38 Bevel gear (drive shaft conversion unit)
39 Rotating gear 41 Rack (flat gear)

Claims (6)

A pair of rotating shafts having a drive source connected to at least one, a pair of first arms having one end connected to the pair of rotating shafts, and one end rotating to the other end of each of the pair of first arms A substrate transfer apparatus comprising a pair of second arms that are coupled to each other and have the same arm length as the first arm, and a substrate support that is rotatably coupled to the other end of each of the pair of second arms. In
A substrate transfer comprising a dead center escape mechanism that applies a rotational force to the second arm only when the first arm and the second arm pass through a dead center position that is parallel to each other. apparatus.   The dead center escape mechanism includes a rotation drive unit that communicates with the rotation shaft, and a rotation drive unit that is provided on the second arm or the substrate support and is engaged with the rotation drive unit when the substrate support passes the dead center position. The substrate transfer apparatus according to claim 1, further comprising an engaging portion that mates. The rotation drive unit includes a fixed gear concentrically installed with the rotation shaft, a first rotation gear that is pivotally supported in the vicinity of one end of the first arm, and meshes with the fixed gear. A second rotating gear that is pivotally supported in the vicinity of the end; and a rotational force transmitting member that transmits the rotational force of the first rotating gear to the second rotating gear;
The engagement portion is fixed to a coupling shaft between the first arm and the second arm, and has an engagement tooth partially engageable with the second rotation gear on an outer peripheral portion. Item 3. The substrate transfer apparatus according to Item 2. The rotation drive unit includes a drive shaft conversion unit that converts a rotation axis of the rotation shaft in a direction orthogonal thereto, and a rotation gear that rotates around the converted rotation axis.
The substrate transfer apparatus according to claim 2, wherein the engaging portion is a spur gear that is provided below the substrate support and is engageable with the rotating gear.   The substrate transfer apparatus according to claim 1, wherein the pair of rotation shafts are disposed at different axial positions and rotate in directions opposite to each other. The substrate transfer apparatus according to claim 1, wherein the pair of rotation shafts are arranged coaxially and rotate in opposite directions and the same direction.

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