Transport robot

Abstract

To provide a carrier robot capable of further reducing a time required for an alignment operation.SOLUTION: A carrier robot A1 comprises: a horizontal arm 2 that can be rotated around a pivot shaft 21 vertical to a support base transmitted by a robot; and a hand 3 that is rotated around a rotational shaft 31 parallel to the pivot shaft 21 with respect to the horizontal arm 2 above the horizontal arm 2, and can hold a plate-like workpiece (wafer) W onto an upper surface. The horizontal arm 2 is provided with a rotational stage 24 which can be rotated around a rotational shaft 241 parallel to or matched to the pivot shaft 21, can be lifted in a shaft direction of the rotational shaft 241, and can hold the plate-like workpiece W onto the upper surface. The hand 3 is formed so that a rotational locus of a holding center O1 corresponded to a center of the plate-like workpiece passes through the rotational shaft 241 in a plan view. The rotational stage 24 is rotated by using an output of a motor provided to the horizontal arm 2 so as to rotate the horizontal arm 2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a transfer robot for transferring plate-like workpieces such as semiconductor wafers. [Background technology]

[0002] For example, in semiconductor processing, transfer robots are used to remove wafers from cassettes and transport them to processing chambers, or to remove wafers that have completed processing in the processing chamber and transport them to the next process. This type of transfer robot is generally equipped with a hand on its upper surface that holds the wafer, and is configured to transport the wafer held in the hand from its source to its destination.

[0003] When a wafer is transported to a processing chamber, it may be necessary for the wafer to be accurately positioned at each reference position in the rotational direction (θ direction) and planar direction (XY direction) at the destination. For this purpose, a device called an aligner is used to perform alignment operations.

[0004] As shown in Patent Document 1, particularly FIG. 3, for example, an aligner includes a rotary table on which a wafer can be placed and sensors for detecting the amount of deviation of the wafer placed on the rotary table from a reference position in the X and Y directions and in the θ direction. The wafer has a circular outer periphery and a notch or orientation flat on this circular outer periphery. For example, by continuously detecting the outer periphery of the wafer while rotating it, the amount of deviation of the wafer's center in the X and Y directions at the time it is placed on the rotary table can be detected. In addition, by detecting the notch or orientation flat while rotating the wafer, the amount of deviation of the wafer in the θ direction at the time it is placed on the rotary table can be detected.

[0005] The deviation in the θ direction can be eliminated by rotating the turntable in a predetermined direction in consideration of the deviation amount detected as described above. The deviation in the X and Y directions can be eliminated by having the robot correct the hand that picked up the wafer from the turntable in the X and Y directions while transferring it to the destination, taking into consideration the deviation amount detected as described above.

[0006] However, the aligner described in the cited document 1 is independent of the transfer robot, which increases the cost of the transfer device consisting of the transfer robot and the aligner, and requires a large floor space for the installation of the transfer device. Moreover, the time required to transfer the wafer between the robot and the aligner delays the throughput, which reduces the processing efficiency of the entire process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-195328 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been devised in light of the above circumstances, and an object of the present invention is to provide a transfer robot that can further reduce the time required for alignment operations. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention employs the following technical means.

[0010] In other words, the transport robot provided by the present invention is a transport robot comprising a horizontal arm that can rotate around a rotation axis that is perpendicular to a support base that is transported by the robot, and a hand that is located above the horizontal arm and can rotate around a rotation axis that is parallel to the rotation axis relative to the horizontal arm, and can hold a plate-shaped workpiece on its upper surface, wherein the horizontal arm is provided with a rotating stage that can rotate around a rotation axis that is parallel to or coincident with the rotation axis, can be raised and lowered in the axial direction of the rotation axis, and can hold the plate-shaped workpiece on its upper surface, and the hand is formed so that the rotation trajectory of the holding center corresponding to the center of the plate-shaped workpiece passes through the rotation axis in a planar view, and the rotating stage is rotated using the output of a motor provided on the horizontal arm to rotate the horizontal arm.

[0011] In a preferred embodiment, the rotating stage is rotated using the output of the motor by looping a belt around a pulley provided on a shaft for transmitting rotational power to the rotating stage, a motor pulley provided on the output shaft of the motor, and a pivot pulley provided on the pivot shaft.

[0012] In a preferred embodiment, a reducer is provided between the pulley provided on the pivot shaft and the support base.

[0013] In a preferred embodiment, the reduction ratio of the reducer is, for example, 1 / 160 to 1 / 50.

[0014] In a preferred embodiment, the motor and the pulley attached to the output shaft of the motor, the shaft for transmitting rotational power to the rotating stage and the pulley attached to it, the pulley attached to the pivot shaft, and the belt looped between these pulleys are all located inside the horizontal arm. [Effects of the Invention]

[0015] In the above configuration, the rotation locus of the holding center of the hand is formed to pass through the rotation axis in a plan view, so that the hand can be rotated around the rotation axis to position the holding center on the rotation axis of the rotation stage.

[0016] The plate-shaped workpiece on the hand transferred above the rotary stage is then lifted and placed on the rotary stage. By rotating the rotary stage in this state and continuously detecting the periphery of the plate-shaped workpiece with a predetermined sensor, the amount of misalignment of the center of the plate-shaped workpiece in the X and Y directions at the time of transfer from the hand to the rotary stage can be detected. If the plate-shaped workpiece is a semiconductor wafer, it has a notch or orientation flat formed on its periphery. By simultaneously detecting this notch or orientation flat, the amount of misalignment of the plate-shaped workpiece in the θ direction at the time of transfer from the hand to the rotary stage can be detected. The misalignment in the θ direction can be eliminated by rotating the rotary stage in a predetermined direction, taking into account the detected misalignment amount. The plate-shaped workpiece with its misalignment in the θ direction thus eliminated is then transferred onto the hand by lowering the rotary stage. The misalignment of the plate-shaped workpiece in the X and Y directions can be eliminated by having the robot correct the hand in the X and Y directions based on the detected misalignment amount and transporting it to the destination.

[0017] As described above, the transfer robot configured as above can perform alignment operations without providing a separate aligner, thereby enabling the size and cost of the entire transfer device to be reduced. Furthermore, since the transfer of plate-shaped workpieces between the hand and the rotating stage can be completed in a short time, the time required for alignment operations can be shortened and the processing efficiency of the entire process can be improved.

[0018] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an overall elevational view of a transport robot according to an embodiment of the present invention; [Figure 2] FIG. [Figure 3] 3 is a longitudinal cross-sectional view of the horizontal arm, corresponding to the cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] 3 is a diagram showing an operating state, and corresponds to a cross-sectional view taken along line III-III in FIG. 2. [Figure 6] FIG. 10 is a plan view of the horizontal arm showing the operating state. [Figure 7] 3 is a diagram showing an operating state, and corresponds to a cross-sectional view taken along line III-III in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0020] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0021] 1 is a schematic diagram showing the overall configuration of a transfer robot A1 according to one embodiment of the present invention. The transfer robot A1 is configured to transfer semiconductor wafers W as plate-like workpieces.

[0022] The transport robot A1 includes a robot 1, a horizontal arm 2, and a hand 3. The robot 1 includes a first arm 111 that is rotatable around a horizontal first axis 11, a second arm 121 that is rotatable around a horizontal second axis 12 at the tip of the first arm 111, and a support base 131 that is rotatable around a horizontal third axis 13 at the tip of the second arm 121. The robot 1 is capable of transferring the support base 131 to any position within a range allowed by the lengths of the first arm 111 and the second arm 121 in a vertical plane perpendicular to the first, second, and third axes 11, 12, and 13. The attitude of the support base 131 is normally controlled so that the rotation axis 21 of the horizontal arm 2 that it rotatably supports faces the vertical direction.

[0023] The horizontal arm 2 is supported on the support base 131 so as to be rotatable about a rotation axis 21. The rotation of the horizontal arm 2 is driven by a rotation motor 22 disposed inside the horizontal arm 2. As shown in FIGS. 3 and 4, the output shaft 221 of the rotation motor 22 is connected to the support base 131 by an endless belt 23 wound between a pulley 222 mounted on the output shaft 221 and a pulley 212 mounted on the rotation axis 21 via a reducer 211. The reducer 211 may have a high reduction ratio, such as a Harmonic Drive (registered trademark). The reduction ratio of this reducer is, for example, 1 / 160 to 1 / 50. In this embodiment, a rotation motor 22 without a reduction function is preferably used. The ratio of the pulley 222 mounted on the output shaft 221 of the rotation motor 22 to the pulley 212 on the rotation axis 21 is not limited, but may be, for example, 1:1.

[0024] As shown in FIG. 2, the hand 3 has a planar shape like a forked fork, and has a holding center O1 on the upper surface where the center of the wafer W (FIG. 5) to be held should be located. In the embodiment shown in the figure, two hands 3 stacked one on top of the other are provided to be rotatable about a vertical rotation axis 31. The rotation of each hand 3 is controlled individually by a motor 32 provided inside the horizontal arm 2 via a belt transmission mechanism 33, for example. In this embodiment, the hand 3 is capable of holding the wafer W by vacuum suction. Alternatively, the hand W may be capable of clamping and holding the periphery of the wafer W using a clamping mechanism.

[0025] In the present invention, a rotary stage 24 that has a rotary shaft 241 and can move up and down is provided on the horizontal arm 2. A specific example of the configuration for this purpose will be described below.

[0026] As shown in FIG. 3, a support plate 25 is provided inside the horizontal arm 2, which can be raised and lowered by a linear actuator such as an air cylinder 251. A rotation shaft 241, which is parallel to or coaxial with the pivot shaft 21, is rotatably supported on the support plate 25. The relationship between the rotation shaft 241 and the hand 3 is such that the distance L1 from the pivot shaft 31 of the hand 3 to the holding center O1 is equal to the distance L2 between the pivot shaft 31 of the hand 3 and the rotation shaft 241 of the rotation stage 24 (FIG. 2). A circular rotation stage 24 is provided on the upper end of the rotation shaft 21. The rotation stage 24 is sized to be able to pass through the space between the fork claws 3a of the hand 3 in the vertical direction, and is capable of holding a wafer W on its upper surface by, for example, suction. In this embodiment, the rotation shaft 241 of the rotation stage 24 is arranged coaxially with the pivot shaft 21 of the horizontal arm 2.

[0027] An intermediate transmission shaft 26 extending vertically is rotatably supported on an auxiliary plate 252 provided below the support plate 25, and the upper end of the intermediate transmission shaft 26 is inserted through a holder 261 that is passed through and held by the support plate 25 and a spline nut 262 that is attached to the holder 261 and is rotatable relative to the holder 261. The intermediate transmission shaft 25 is a spline shaft, and the spline nut 262 is movable in the axial direction with respect to the intermediate transmission shaft 26 but is unable to rotate relative to the intermediate transmission shaft 26. Therefore, regardless of the position of the support plate 25 or the spline nut 262 in their vertical stroke, the rotation of the intermediate transmission shaft 26 is transmitted to the spline nut 262, and the spline nut 262 rotates together with the intermediate transmission shaft 26. Note that a rotary ball spline LTR type manufactured by THK Corporation can be suitably used as a commercially available product that can realize the function of the combination of the intermediate transmission shaft 26 (spline shaft), holder 261, and spline nut 262.

[0028] A pulley 263 is provided on the spline nut 262, and a pulley 242 is provided below the rotation shaft 241 of the rotation stage 24, with an endless belt 27 running between these pulleys 263 and 242. A pulley 264 is provided at the lower end of the intermediate transmission shaft 25, and an endless belt 23 is run around the pulley 264 in common between a pulley 222 provided on the output shaft 221 of the rotation motor 22 and a pulley 212 provided on the rotation shaft 21 via a reducer 211 (FIG. 4). The ratio of the pulleys 222 and 264 is not limited, but may be, for example, 1 to 2:1. As a result, when the rotation motor 22 is driven, the horizontal arm 2 swings around the rotation shaft 21 and the rotation stage 24 rotates around the rotation shaft 241 at the same time. However, since the reduction ratio of the reducer 211 is large, even if the rotation stage 24 rotates once (360°), the rotation angle of the horizontal arm 2 is small.

[0029] Next, an example of the operation when the transfer robot A1 having the above configuration is used to perform an alignment operation on the wafer W will be described.

[0030] 5, the rotary stage 24 is positioned below the hand 3, and the holding center O1 of the hand 3 carrying the wafer W received from the transfer source is aligned in plan with the rotation axis 241 of the rotary stage 24. At this time, as shown in FIG. O is displaced in the XY direction (displacement amount δ XY ), and there is also a shift in the θ direction (shift amount δ θ ) may occur.

[0031] 7, the rotary stage 24 is raised to transfer the wafer W onto the rotary stage 24. In this state, the rotary stage 24 is rotated and the outer periphery of the wafer W is continuously detected by a predetermined sensor (not shown), thereby determining the center W of the wafer W at the time of transfer from the hand 3 to the rotary stage 24. O XY direction deviation δ XY The wafer W has a notch W on the periphery. NOrientation flat is formed, so at the same time this notch W N Alternatively, by detecting the orientation flat, the amount of deviation δ of the wafer W in the θ direction at the time when the wafer W is transferred from the hand 3 to the rotary stage 24 can be determined. θ The deviation in the θ direction can be calculated by the deviation amount δ θ The wafer W, whose deviation in the θ direction has been eliminated in this way, is transferred onto the hand 3 by lowering the rotary stage 24, and the deviation of the wafer W in the X and Y directions is corrected by the deviation amount δ detected as described above. XY In light of this, the robot 1 or the horizontal arm 2 can correct the hand 3 in the X and Y directions while transferring it to the destination, thereby resolving this problem.

[0032] In the above configuration, the rotation of the rotary stage 24 is performed using the output of the rotation motor 22 for rotating the horizontal arm 2, so there is no need to provide a separate drive system for the rotary stage 24.

[0033] When the rotation stage 24 is rotated as described above, the horizontal arm 2 also rotates. However, because the reducer 211 has a high reduction ratio as described above, the rotation angle of the horizontal arm 2 is small, and the horizontal arm 2 does not rotate greatly during alignment operations and interfere with peripheral equipment, thereby maintaining the compactness of the entire apparatus.

[0034] As described above, the transfer robot A1 having the above configuration can perform alignment operations without providing a separate aligner, thereby reducing the size and cost of the entire transfer device. Furthermore, since the transfer of the wafer W between the hand 3 and the rotary stage 24 can be performed in a short time, the time required for alignment operations can be shortened and the processing efficiency of the entire process can be improved.

[0035] Of course, the scope of the present invention is not limited to the above-described embodiments, and all modifications that fall within the meaning of the claims are encompassed within the scope of the present invention.

[0036] For example, in the embodiment, the rotation axis 241 of the rotating stage 24 and the pivot axis 21 of the horizontal arm 2 are aligned, but this is not necessarily required. It is sufficient to make the distance L1 between the rotation axis 31 of the hand 3 and the holding center O1 equal to the distance L2 between the rotation axis 31 of the hand 3 and the rotation axis 241 of the rotating stage 24.

[0037] Furthermore, the configuration for raising and lowering the rotating stage 24, which rotates using the output of the rotation motor 22 of the horizontal arm 2, is not limited to that in the embodiment.

[0038] Furthermore, the configuration of the robot 1 that transfers the support base 131 that supports the horizontal arm 2 is not limited to that of the above-mentioned embodiment, and may be any configuration that can transfer the support base 131 to any position within a vertical plane. [Explanation of symbols]

[0039] A1: Transport robot, W: Wafer (plate-shaped workpiece), W O : Center (of wafer), 1: Robot, 131: Support base, 2: Horizontal arm, 21: Swivel shaft, 211: Reducer, 212: Pulley, 22: Swivel motor, 221: Output shaft, 222: Pulley, 23: Endless belt, 24: Rotation stage, 241: Rotation shaft, 264: Pulley, 27: Endless belt, 3: Hand, 31: Rotation shaft

Claims

1. a horizontal arm that is pivotable about a pivot axis perpendicular to a support base that is transferred by the robot; a hand that is located above the horizontal arm and can rotate relative to the horizontal arm around a rotation axis that is parallel to the rotation axis, and that can hold a plate-shaped workpiece on an upper surface thereof, The horizontal arm is provided with a rotation stage that is rotatable around a rotation axis that is parallel to or coincident with the pivot axis, that is movable up and down in the axial direction of the rotation axis, and that can hold the plate-shaped workpiece on its upper surface; the hand is formed so that a rotation locus of a holding center corresponding to the center of the plate-like workpiece passes through the rotation axis in a plan view, The transfer robot is characterized in that the rotation stage is rotated by utilizing the output of a motor provided on the horizontal arm to rotate the horizontal arm.

2. 2. The transport robot according to claim 1, wherein the rotating stage is rotated using the output of the motor by looping a belt around a pulley provided on a shaft for transmitting rotational power to the rotating stage, a pulley provided on the output shaft of the motor, and a pulley provided on the swivel shaft.

3. 3. The transfer robot according to claim 2, further comprising a reducer provided between the pulley provided on the pivot shaft and the support base.

4. 4. The transport robot according to claim 3, wherein the reduction ratio of the reducer is 1 / 160 to 1 / 50.

5. 5. The transport robot according to claim 4, wherein the motor and the pulley attached to the output shaft of the motor, the shaft for transmitting rotational power to the rotating stage and the pulley attached to the shaft, the pulley attached to the pivot shaft, and the belt looped between these pulleys are all provided inside the horizontal arm.

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