JP2006041233A - Conveyance arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize compact arm structure capable of conveying stably and highly accurately a substrate conveying base arranged at the edge of the conveyance arm which connects two sets of parallel links. <P>SOLUTION: The conveyance arm 1 is constituted such that a first parallel link 10 and a second parallel link 20 are connected by a shared short joint 26, and a conveying base 50 arranged at the free end of the second parallel link 20 is made to move linearly by rotating operation given to the rotating axis of the arm end of the first parallel link 10. From each joint consisting of the shared short joint 26, an underside connecting plate 16 for connecting end fulcrums having a predetermined amount extension of respective arms 11 and 12 of the first parallel link 10, and an upper side connecting plate for connecting medium fulcrums 23, 24 having a predetermined amount inside of respective arms 21 and 22 of the second parallel link 20, are connected to a plate spring 18 arranged for maintaining parallel condition, so that lateral displacement to the direction of linear movement between connecting plates 16 and 17 may be regulated and relative displacement may be permitted by maintaining parallel condition of the connecting plates 16 and 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transfer arm, and more particularly to a transfer arm that is mounted on a semiconductor manufacturing apparatus or the like and can transfer a substrate with high accuracy in a compact and stable state.

  In general, a semiconductor manufacturing apparatus is provided with a substrate transfer device for moving a substrate such as a wafer in a predetermined operation sequence. This type of substrate transfer apparatus is required to have a high-precision operation and a clean operation environment that does not generate dust. In order to meet this demand, the applicant has already been able to transport a substrate with high accuracy, maintain a clean environment with little wear on moving parts, etc. It has been proposed (see Patent Document 1).

6A is a bent state of the transfer arm 100 already proposed by the applicant, and FIG. 6B is a plan view showing an extended state of the arm. The transport arm 100 is configured such that the two sets of parallel links 110 and 120 supported by the rotation axes R ₁₀₁ and R ₁₀₂ of the base plate 102 as a whole are connected with a short joint and operate as a unit. Yes.

The transfer arm 100 is a 1-way joints 114 of the short sections 113 formed by connecting the shaft end of the arm 111 and 112 parallel arrangement of two a drive rotational axis R _101, the other joint 115 as a driven rotation shaft R ₁₀₂ Yes. A first parallel for rotating the arms 111 and 112 with respect to the respective rotation axes R ₁₀₁ and R ₁₀₂ while holding the parallelogram with the other short sections 116 facing the short section 113 by the rotation of the drive rotation axis R _101. The link 110 and the short link 126 shared with the short link 116 of the first parallel link 110 are connected, and the ends of the two arms 121 and 122 arranged in parallel are connected to both end joints 127 and 128 of the short link 126. The second parallel link 120 and the linear guide 132 (FIG. 6B) that linearly guides in the direction orthogonal to the short node 116 (126) are the main structures and are provided to the arm 111 of the first parallel link 110. Synchronous link 1 that causes the arm 122 of the second parallel link 120 to rotate at an equal angle opposite to the first parallel link 110 by linearly moving the slider 131 of the linear guide 132 by the turning operation. 40 and a transfer table 150 on which a transfer target such as a substrate (not shown) is placed.

In the transfer arm 100 having this configuration, a clockwise turning movement about the rotation axis R _101, transfer arm so as to deform the parallel link 110 and 120 from the state shown in FIG. 6 (a), the conveying table 150 is linearly moved in the direction of arrow A to the state shown in FIG. FIG. 7 is a link model diagram illustrating the stretched state and the bent state of the parallel links of the transfer arm 100 at this time. As shown in the figure, in the transport arm 100, the base plate 102 (FIG. 6A) is rotated in a bent state, and the transport base 150 is swung by a predetermined angle in a predetermined rotation direction with a turning radius R _r. , by extension of the arm due to the turning operation of the rotary shaft R ₁₀₁ can be only moved linearly conveying distance L in the arrow a direction.

JP 2001-185596 A.

  By the way, since the above-mentioned linear guide includes the synchronization link, the number of members is large, the joint portion is thick, and it is difficult to reduce the thickness of the arm bending portion. In addition, the linear guide has a structure in which the bearing ball continuously rolls along a linear internal path, but there is a risk that it may be inferior in lubricity compared to a conventional ball bearing with a short rolling path, and the smoothness of the arm. When bending and extension are required, it is desired to use a proven ball bearing in a movable part such as each joint.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a transport arm that has a compact and thin arm structure and can carry a substrate with high precision.

  In order to achieve the above object, according to the present invention, a short link of a first parallel link and a short link of a second parallel link are shared and connected, and a turning motion applied to an arm end of the first parallel link. In the transfer arm, the angle formed by the arm of the first parallel link and the arm of the second parallel link is changed to linearly move the transfer table provided at the short node on the free end side of the second parallel link. From the joints constituting the shared short nodes, from the joints of the first parallel links that connect the end fulcrums obtained by extending the arms of the first parallel links by a predetermined amount, and the joints of the second parallel links The second connecting member that connects the intermediate fulcrum on the inner side of the predetermined amount on each arm regulates the shift in the linear movement direction between the two connecting members, and maintains a parallel state between the two connecting members. Connect with a regulating member that allows relative displacement. Characterized by comprising parallel retaining portion made.

  The short link of the first parallel link and the short link of the second parallel link are connected in common, and the arm of the first parallel link and the second are connected by a turning motion applied to the arm end of the first parallel link. In each of the transfer arms configured to linearly move the transfer table provided at the short end on the free end of the second parallel link by changing the angle formed by the arms of the parallel link, Between a joint, a first connecting member that connects a predetermined amount inside intermediate fulcrum on each arm from the joint of the first parallel link, and an end fulcrum obtained by extending each arm of the second parallel link by a predetermined amount The second connecting member that connects the two is connected with a regulating member that restricts the displacement in the linear movement direction between the two connecting members and that allows the relative displacement while maintaining a parallel state between the two connecting members. Characterized by having a parallel holding part To.

  At this time, it is preferable that the restricting member is a plate-like spring member spanned between the first connecting member and the second connecting member.

  Further, the distance from the joint of each arm of the first parallel link of the first connecting member to the end fulcrum, and the joint of each arm of the second parallel link of the second connecting member A distance to an intermediate fulcrum, or a distance from each joint of each arm of the first parallel link of the first connecting member to the intermediate fulcrum, and each arm of the second parallel link of the second connecting member. It is preferable that the distance from the joint to the end fulcrum is set equal.

  As described above, according to the transport arm of the present invention, the substrate can be transported with high accuracy by a compact apparatus configuration, and the lubrication characteristic of the movable part is excellent, and there is almost no wear. It is possible to maintain a clean environment for a long period of time, and as a result, high durability can be obtained.

  Hereinafter, as the best mode for carrying out the transfer arm of the present invention, the following embodiments will be described with reference to the accompanying drawings.

Hereinafter, an embodiment of a transfer arm of the present invention will be described with reference to the accompanying drawings. FIG. 1A is a plan view showing the entire transfer arm 1 supported by the link drive rotation axis R ₁ of the base plate 2 as a whole. FIG. 1B is an arrow side view showing a bent state of the transport arm and a positional relationship between a plate spring 18 as a regulating member, which will be described later, and connection plates 16, 17 (to be described later) to which the plate spring 18 is fixed. The transfer arm 1 is composed of two sets of parallel links 10 and 20 that are connected and operated in a similar manner to the known transfer arm using the two sets of parallel links shown in Patent Document 1, and operates. The entire transport arm is supported on the upper end of an arm turning drive shaft (not shown) that is mounted at the center and can rotate at a predetermined turning direction and turning speed by rotation of a drive motor (not shown).

As shown in FIG. 1A, the transfer arm 1 has two parallel arrangements in which a joint 6 that coincides with the central axis of the apparatus is fixed to the upper end of the link drive rotation axis R ₁ and the other end is a joint 7. A first parallel link 10 which forms a parallelogram with a connecting plate 5 as a short node connecting the shaft ends of the arms 11 and 12, and a short node 26 at a position facing the connecting plate 5, and a first parallel link A second parallel link 20 in which the ends of two parallel-arranged arms 21 and 22 each supported as a rotation axis are connected to both end joints 27 and 28 as short nodes 26 shared with 10; A ball bearing 31 (FIG. 1 (b)) is attached to the end fulcrums 13 and 14 positioned at the member ends 11a of the arms 11 and 12 with the joints 27 and 28 at both ends of the short link 26 of the parallel link 10 slightly extended. The lower surface connecting plate 16 attached via the An upper surface connecting plate 17 attached to intermediate fulcrums 23 and 24 located slightly inward from the joints 27 and 28 of the arms 21 and 22 of the parallel link 20 via ball bearings 32 (FIG. 1B); The parallel holding portion 30 composed of the lower surface connecting plate 16 and the plate spring 18 as a regulating member fixed to the outer end of the upper surface connecting plate 17 and the free end of the second parallel link 20 function as a short node 25, It is comprised from the conveyance stand 50 which mounts conveyance objects, such as a board | substrate which does not.

Hereinafter, the configuration of each joint (axis) of the transfer arm 1 and each member connected via the joint (axis) will be described.
[Configuration of parallel links]
The structure of the attachment structure to the base of the 1st parallel link 10 is demonstrated with reference to FIGS. FIG. 1A is a plan view showing the transfer arm in a state stopped at the origin position of the transfer arm 1 as one embodiment. As shown in the figure, the two sets of parallel links 10 and 20 where the joints 27 and 28 are shared and connected are in the most bent state. At this time, as shown in FIG. 1A, the arm 11 of the first parallel link 10 has a transport arm turning drive shaft (not shown) and a link drive rotation axis R ₁ arranged coaxially with respect to the central axis of the apparatus. The shaft end is supported on the base plate 2 by a bolt (not shown) via a ball bearing (not shown) so as to be independently rotatable. The base plate 2 has a disk shape in plan view, and is fixed by bolting or the like on a part of the fixing portion 3 in the vacuum space according to the specifications. Each of the transfer arm rotation drive shaft and the link drive rotation axis R ₁ can be appropriately set by a control device (not shown) so that the entire transfer arm can be rotated and the transfer table 50 can be linearly moved by deformation of the link mechanism independently or simultaneously. It is like that.

  The configuration of the first parallel link 10 will be described with reference to FIGS. 1 and 2, FIGS. 3 and 4. 3 and 4 are diagrams based on a link model in which the link mechanism formed by the members of the parallel links 10 and 20 is indicated by an axis. As shown in FIG. 3, in the bent state of the transfer arm, the arms 11 and 12 of the first parallel link have the central axis of the joint portion as the apex of the parallel link, but the shape is as shown in FIG. As shown, both ends 11a, 11a of the member are discs so that ball bearings (29, 31, 32: FIG. 1 (b)) having predetermined thicknesses and diameters arranged at respective joint positions can be incorporated into the member ends. It has a shape.

  Similarly, the configuration of the second parallel link 20 will be described. The disk portions 21a and 22a of the arms 21 and 22 of the second parallel link 20 are bolts (via the ball bearings 29 (FIG. 1B)) at the joints 27 and 28 at the ends of the arms 11 and 12 of the first parallel link. (Not shown). On the other hand, at the position of the short node 25 at the free end of each arm 22, 21 of the second parallel link 20, a transport base 50 is fixed on a ball bearing constituting the joint. The shape of the transport table 50 is set so as to have an optimal fork shape according to the size, weight, etc. of the substrate to be placed, liquid crystal glass or the like (not shown). In the present embodiment, for the sake of convenience, it is indicated by a substantially quadrilateral with a virtual line. Note that the shape of the members constituting each parallel link can be set to an appropriate size and shape as long as it can hold the bearing that supports the shaft member of each link member and there is no interference of the members in the deformation of the link shape. Needless to say, you can.

[Configuration of parallel holding part]
As shown in FIG. 1B, FIG. 2B, FIG. 3 (bent state), and FIG. 4 (extended state), on the extension line of the arms 11 and 12 passing through the joints 27 and 28 of the first parallel link 10 At the end fulcrums 13 and 14, the lower surface connecting plate 16 is attached to the lower surfaces of the disk portions 11a and 12a of the arms 11 and 12 via ball bearings 31 having a smaller diameter than the ball bearings 29 of the joints 27 and 28, respectively. It is worn. Since the lower surface connecting plate 16 connects the end fulcrums 13 and 14 via the ball bearings 31, when the parallelogram of the first parallel link 10 is deformed from, for example, the state of FIGS. The connecting plate 16 can be displaced (moved) following the deformation of the first parallel link 10 while maintaining a parallel state with the portion constituting the short node 26.

  As described above, the first parallel link 10 includes the short links 26 between the arms 11 and 12, the connecting plate 5 and the joints 27 and 28, and the lower surface connecting plate 16 connecting the end fulcrums 13 and 14. . On the other hand, the second parallel link 20 includes the arms 21 and 22, the short nodes 25, and the upper surface connecting plate 17 that connects the intermediate fulcrums 23 and 24 near the joints 27 and 28 of the arms 11 and 22. In this structure, the end portion of the lower surface connecting plate 16 and the end portion of the upper surface connecting plate 17 are connected by a plate spring 18 having a predetermined rigidity as a restricting member, thereby causing deformation of the parallel links 10 and 20. A parallel holding unit 30 is configured to reliably hold the linear movement of the transport table 50.

  That is, the parallel holding portion 30 has the end fulcrums 13 and 14 at arbitrary positions on the center lines on the arms 11 and 12, respectively, as shown in FIGS. , 14 so that a flat parallelogram can be formed. Similarly, the intermediate fulcrums 23, 24 are located near the joints 27, 28 on the center lines on the arms 21, 22 via the ball bearings 32, respectively. Thus, the upper surface connecting plate 17 is connected, and the joints 27 and 28 and the intermediate fulcrums 23 and 24 of the upper surface connecting plate 17 are arranged so as to form a parallelogram. The link mechanism is geometrically set so that the distances from the joint 27 to the end fulcrum 13 and the intermediate fulcrum 23 and from the joint 28 to the end fulcrums 14 and 24 are equal. That is, an isosceles triangle (ΔEIC, ΔFJD) having the joints 27 and 28 as vertices is formed, and the link is such that the angle of the vertex changes when the first parallel link 10 and the second parallel link 20 are deformed. Transforms. In FIGS. 3 and 4, for the sake of simplification, an alphabetic character is added to the vertex of each link.

  The movement of the link mechanism of the transfer arm realizes linear movement of the transfer table 50 in the A direction (see FIGS. 1 to 2, FIG. 3 to FIGS. 4 and 5). In order for the carriage 50 to go straight on the imaginary line C in the direction A, as described above, the isosceles triangles (ΔEIC, ΔFJD) do not become inequilateral triangles, that is, the end fulcrums 13 and 14 are moved. It is necessary that the lower connecting plate 16 to be connected and the upper connecting plate 17 to connect the intermediate fulcrums 23 and 24 are held so as not to be relatively displaced in the X direction. Therefore, in the present invention, a steel plate having a thickness of 0.2 mm and a width of 80 mm is used as the regulating member in the present invention, and is fixed to the end faces of the upper surface connecting plate 17 and the lower surface connecting plate 16 with bolts 19. Further, when the transfer arm 1 is bent and extended, the straight line (IJ) connecting the end fulcrums 13 and 14 and the straight line (CD) connecting the intermediate fulcrums 23 and 24 have the same amount in the Y direction across the joints 27 and 28. Only the relative position changes. The above-described leaf spring 18 is set to a margin length that can absorb the displacement in the Y direction between the connecting plate 16 and the connecting plate 17 caused by the relative position change.

  The plate-like spring as the restricting member is not limited to the above-described dimensions as long as it is a member having torsional rigidity capable of absorbing the displacement in the Y direction and restraining the displacement in the A direction. Needless to say, the material can be appropriately selected. In addition, various linear guides, link mechanisms, and the like can be used as long as the mechanism can achieve the same displacement regulation and achieve the same effect.

  Further, as another embodiment of the parallel holding portion 30 formed in the connection of the first parallel link 10 and the second parallel link 20 described above, the end fulcrums 13 and 14 are on center lines on the arms 21 and 22, respectively. The joints 27 and 28 are provided at positions extended by a predetermined amount, and a flat parallelogram is formed at the four points of the joints 27 and 28 and the end fulcrums 13 and 14. Similarly, the intermediate fulcrums 23 and 24 are respectively connected to the arms. 11 and 12 may be provided at bearing positions arranged on the arms 11 and 12 close to the joints 27 and 28 on the center line on the center line 11 and 12, so that a parallelogram of the same shape may be formed.

Hereinafter, the linear movement of the transfer arm 1 will be described with reference to FIGS.
The arm 11 fastened to the upper end of the link drive rotation axis R ₁ rotates about the rotation axis R ₁ , and as a result, the first parallel link 10 moves to the arm 11 as shown in FIGS. , 12, the connecting plate 5, and the bottom connecting plate 16 are deformed from a flat quadrilateral to a rectangular to a flat quadrilateral according to the turning motion. At the same time, the initially flat parallelogram (□ ECDF) composed of the end fulcrums 13 and 14 and the joints 27 and 28 on which the lower surface connecting plate 16 is supported is similarly deformed. At this time, the second parallel link 20 is connected to the first parallel link 10 via the parallel holding portion 30 via the joints 27 and 28. Accordingly, the upper surface connection plate 17 attached so as to connect the intermediate fulcrums 23 and 24 on the arms 21 and 22 of the second parallel link 20 is further fixed to the lower surface connection plate 16 of the first parallel link 10. The relative displacement with respect to the X direction is restricted by the spring 18. The parallelogram (□ ECDF, □ IEFJ) formed by a part of the first parallel link 10 and the second parallel link 20 maintains the symmetrical shape with the short axis 26 as the symmetry axis (EF), and is the first. It deforms through the same shape as a parallel link. Therefore, the second parallel link 20 also has a parallelogram (□ EFHG) with the joints 27 and 28 as one side deformed in the same manner as the parallelogram (□ EFBA) of the first parallel link 10, and as a result, the second parallel link. The carriage 50 on the 20 short nodes 25 can linearly move on the virtual line C in the direction of arrow A (see FIGS. 2 and 4).

  FIG. 5 shows the first parallel link 10 and the second parallel link 20 of the present invention, the lower surface connecting plate 16 constituting the parallel holding portion 30 attached to each arm, the upper surface connecting plate 17, and the lower surface connecting plate. 6 is a schematic link model diagram showing a positional relationship between a plate-like spring 18 that connects 16 and the upper surface connecting plate 17 in accordance with the bent and extended states of the transfer arm 1. FIG. As shown in the figure, in the state (e) in which the first parallel link 10 and the second parallel link 20 are most bent to the most extended state (e), the lower surface connection plate 16 and the upper surface connection plate 17 The distance between them is large in the state where the upper and lower parallel links 10 and 20 in FIG. 7B overlap, and in this state, the plate spring 18 is shifted most in the Y direction. The plate-like spring 18 is set to have a shape and dimension so as not to be in an excessive stress state even in this state.

The top view which showed one Example (origin position: arm bending state) of the conveyance arm by this invention, a partial cross section arm side view. The top view which showed the expansion | extension state of the conveyance arm shown in FIG. 1, the partial cross section arm side view. The link model figure in the arm state shown in FIG. The link model figure in the arm state shown in FIG. The state explanatory drawing which showed the bending | flexion and expansion | extension state of the arm by a link model figure in steps. The top view which showed an example (the bending | flexion and expansion | extension state) of the conventional conveyance arm. The link model figure which showed the bending | flexion and expansion | extension state of the conveyance arm shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer arm 2 Base plate 5 Connection plate 10 1st parallel link 11, 12, 21, 22 Arm 11a, 12a, 21a, 22a Member end 13, 14 End fulcrum 16 Lower surface connection plate 17 Upper surface connection plate 18 Leaf spring 20 Second parallel links 23, 24 Intermediate fulcrums 25, 26 Short node 30 Parallel holding part 50 Transport base R ₁ link drive rotary shaft

Claims (5)

  The short link of the first parallel link and the short link of the second parallel link are connected in common, and the arm of the first parallel link and the second are connected by a turning motion applied to the arm end of the first parallel link. In each of the transfer arms configured to linearly move the transfer table provided at the short end on the free end of the second parallel link by changing the angle formed by the arms of the parallel link, A first connecting member that connects between the end fulcrum obtained by extending each arm of the first parallel link by a predetermined amount from the joint, and a middle fulcrum on the inner side by a predetermined amount on each arm from the joint of the second parallel link. And a second connecting member connected to each other by a restricting member that restricts the displacement of the connecting members in the linear movement direction and maintains a parallel state between the connecting members and allows relative displacement. Characterized by having a parallel holding part Transport arm to.   The short link of the first parallel link and the short link of the second parallel link are connected in common, and the arm of the first parallel link and the second are connected by a turning motion applied to the arm end of the first parallel link. In each of the transfer arms configured to linearly move the transfer table provided at the short end on the free end of the second parallel link by changing the angle formed by the arms of the parallel link, Between a joint, a first connecting member that connects a predetermined amount inside intermediate fulcrum on each arm from the joint of the first parallel link, and an end fulcrum obtained by extending each arm of the second parallel link by a predetermined amount The second connecting member that connects the two is connected with a restricting member that restricts the displacement in the linear movement direction between the two connecting members and allows the relative displacement while maintaining a parallel state between the two connecting members. Characterized by having a parallel holding part Transport arm to.   3. The transport arm according to claim 1, wherein the restricting member is a plate-like spring member spanned between the first connecting member and the second connecting member.   The distance from the joint of each arm of the first parallel link of the first connecting member to the end fulcrum, and the intermediate fulcrum from the joint of each arm of the second parallel link of the second connecting member The transfer arm according to claim 1, wherein the distance to the transfer arm is equal.   The distance from the joint of each arm of the first parallel link of the first connecting member to the intermediate fulcrum, and the end fulcrum from the joint of each arm of the second parallel link of the second connecting member The transfer arm according to claim 2, wherein the distance to the transfer arm is equal.

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