Robot with driven motion of end effector

Abstract

To provide a robot with a following operation of an end effector so as to increase throughput and a capacity factor of a related facility as well as reducing a cycle time by the minimization of a transfer time.SOLUTION: In a robot 28 having a robot driving device and a robot arm mechanism 30, a first link (upper arm) 34 of the robot arm mechanism is connected to the robot driving device in a first driving shaft, and a second link (front arm) 36 is coupled to an upper arm in a rotational joint 46, and can be rotated around the rotational joint. The rotational joint can be driven by a first band mechanism 48 coupled to a second driving shaft, an end effector 38 is coupled to the front arm by a rotational joint 56, and can be rotated to a circumference of the rotational joint 56. The rotational joint 56 can be driven by a second band mechanism 58 coupled to the first rotational joint, and the second band mechanism provides a variable transfer ratio.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The exemplary and non-limiting embodiments generally relate to robots with end effectors, and more specifically to robots with driven motion of the end effectors. Background

[0002] Vacuum, atmospheric, and controlled environment processing for applications such as semiconductors, LEDs (Light Emitting Diodes), solar power, MEMS (Micro Electro Mechanical Systems), or other device manufacturing utilize robotic technology and other forms of automation to transport substrates and their associated transporters to or from storage, processing, or other locations. Such transport of substrates may involve moving individual substrates or groups of substrates using a single arm transporting one or more substrates, or using multiple arms, each transporting one or more substrates. Much of the manufacturing takes place in clean or vacuum environments where footprint and volume are critical, such as in semiconductor manufacturing. Furthermore, automated transport is often implemented when minimizing transport time leads to reduced cycle times and increased throughput and utilization of associated equipment. Summary

[0003] The following abstract is provided for illustrative purposes only and does not limit the scope of the claims.

[0004] In one example, a drive unit having at least three drive motors and at least three coaxial drive shafts connected to each of the at least three drive motors; Robot arm and; A transport device is provided that includes the following: Here, the robot arm is An upper arm connected to the first drive shaft of the at least three coaxial drive shafts; A first forearm connected to the upper arm at the first rotational joint; A second forearm connected to the upper arm at a second rotational joint arranged coaxially with the first rotational joint; A first end effector is connected to the first forearm at a third rotational joint and is rotatable about the third rotational joint; A second end effector is connected to the second forearm at a fourth rotational joint and is rotatable about the fourth rotational joint; Equipped with, At least one of the upper arm, the first forearm, and the second forearm is equipped with a band mechanism having at least one pulley having a non-circular outer diameter, and the band mechanism is Between one of the first to fourth rotational joints and another one, Between one of the first to fourth rotational joints and one of the at least three coaxial drive shafts, Located; The band mechanism is configured to provide a variable transfer ratio, which is selected such that the orientation of the first end effector changes in a predetermined manner as a function of the position of the first forearm relative to the upper arm, and the variable transfer ratio is selected such that, when the upper arm and the first forearm are driven, a reference point on the first end effector follows a predetermined path in a predetermined and changed orientation.

[0005] In another example, a transport device is provided comprising a drive unit having at least three drive motors and at least three coaxial drive shafts connected to each of the at least three drive motors, and a robot arm. Here, the robot arm is An upper arm connected to the first drive shaft of the at least three coaxial drive shafts; A first forearm connected to the upper arm at the first rotational joint; A second forearm connected to the upper arm at a second rotational joint located at a distance from the first rotational joint; A first end effector is connected to the first forearm at a third rotational joint and is rotatable about the third rotational joint; A second end effector is connected to the second forearm at a fourth rotational joint and is rotatable about the fourth rotational joint; Equipped with, At least one of the upper arm, the first forearm, and the second forearm is equipped with a band mechanism having at least one pulley having a non-circular outer diameter, and the band mechanism is Between one of the first to fourth rotational joints and another one, Between one of the first to fourth rotational joints and one of the at least three coaxial drive shafts, Located; The band mechanism is configured to provide a variable transfer ratio, which is selected such that the orientation of the first end effector changes in a predetermined manner as a function of the position of the first forearm relative to the upper arm, and the variable transfer ratio is selected such that, when the upper arm and the first forearm are driven, a reference point on the first end effector follows a predetermined path in a predetermined and changed orientation.

[0006] In another example, a drive unit having at least one motor and at least one drive shaft connected to each of the at least one motor, and a robot arm A transport device is provided that includes the following: Here, the robot arm is At least one upper arm connected to the aforementioned at least one drive shaft; A first forearm connected to at least one upper arm at the first rotational joint; A second forearm connected to at least one upper arm at the second rotational joint; A first end effector is connected to the first forearm at a third rotational joint and is rotatable about the third rotational joint; A second end effector is connected to the second forearm at the fourth rotational joint and is rotatable about the fourth rotational joint; Equipped with, At least one of the at least one upper arm, the first upper arm, or the first forearm, has internally a mechanism configured to provide a variable transfer ratio, wherein the variable transfer ratio is selected such that the orientation of the first end effector changes in a predetermined manner as a function of the position of the first forearm relative to the first upper arm, and the variable transfer ratio is selected such that, when the first upper arm and the first forearm are driven, a reference point on the first end effector follows a predetermined path in a predetermined and changed orientation.

[0007] In another example, the device comprises a drive unit and a robotic arm. The drive unit comprises a first drive shaft rotatable around a first rotation axis and a second drive shaft rotatable around a second rotation axis, the second drive shaft being coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft. The robotic arm comprises an upper arm connected to the drive unit at the first drive shaft, a forearm coupled to the upper arm, and an end effector coupled to the forearm, the forearm being coupled to the upper arm at a first rotary joint and rotatable around the first rotary joint, the first rotary joint being driveable by a first band mechanism coupled to the second drive shaft, the end effector being coupled to the forearm at a second rotary joint and rotatable around the second rotary joint, the second rotary joint being driveable by a second band mechanism coupled to the first rotary joint. The second band mechanism is configured to provide a variable transmission ratio. In another example, the device comprises a drive unit and a robotic arm. The drive unit comprises a first drive shaft rotatable around a first rotation axis, a second drive shaft rotatable around a second rotation axis, and a third drive shaft rotatable around a third rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft, and the third drive shaft is coaxial with the second drive shaft, partially located inside the second drive shaft, and axially rotatable within the second drive shaft. The robot arm comprises an upper arm connected to the drive device at the first drive axis, a forearm coupled to the upper arm, and a first end effector and a second end effector coupled to the forearm, wherein the forearm is coupled to the upper arm at a first rotary joint and is rotatable around the first rotary joint, the first rotary joint is driveable by a single-stage band mechanism, the single-stage band mechanism comprises a first shoulder pulley driveable by the third drive axis, a first elbow pulley partially forming the first rotary joint, and a band, belt, or cable configured to transmit motion between the first shoulder pulley and the first elbow pulley, the first end effector and the second end effector are coupled to the forearm at a second rotary joint, and the orientation of the first end effector and the second end effector is controlled via a two-stage band mechanism. The first stage of the two-stage band mechanism comprises a second shoulder pulley driveable by the second drive shaft, a second elbow pulley partially forming the first rotational joint, and an upper band, belt, or cable configured to transmit motion between the second shoulder pulley and the second elbow pulley.The second stage of the two-stage band mechanism comprises a third elbow pulley coupled to the second elbow pulley, a first wrist pulley coupled to the first end effector, and a first lower band, belt, or cable configured to transmit motion between the third elbow pulley and the first wrist pulley. The second stage of the two-stage band mechanism further comprises a fourth elbow pulley coupled to the second elbow pulley, a second wrist pulley coupled to the second end effector, and a second lower band, belt, or cable configured to transmit motion between the fourth elbow pulley and the second wrist pulley. At least one of the motions between the first shoulder pulley and the first elbow pulley, the motion between the second shoulder pulley and the second elbow pulley, the motion between the third elbow pulley and the first wrist pulley, and the motion between the fourth elbow pulley and the second wrist pulley is performed with a variable transmission ratio. In another example, the device comprises a drive unit, a first robotic arm, and a second robotic arm. The drive unit comprises a first drive shaft rotatable around a first rotation axis, a second drive shaft rotatable around a second rotation axis, and a third drive shaft rotatable around a third rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft, and the third drive shaft is coaxial with the second drive shaft, partially located inside the second drive shaft, and axially rotatable within the second drive shaft. The first robot arm comprises a first upper arm connected to the drive device at a first drive axis, a first forearm coupled to the first upper arm, and a first end effector coupled to the first forearm, wherein the first forearm is coupled to the first upper arm at a first rotary joint, the first rotary joint is driveable by the second drive axis using a first band mechanism, and the first end effector is coupled to the first forearm at a third rotary joint, the third rotary joint is driveable by the first rotary joint using a third band mechanism. The second robot arm comprises a second upper arm connected to the drive device at the third drive axis, a second forearm coupled to the second upper arm, and a second end effector coupled to the second forearm, wherein the second forearm is coupled to the second upper arm at a second rotary joint, the second rotary joint is driveable by the second drive axis using a second band mechanism, and the second end effector is coupled to the second forearm at a fourth rotary joint, the fourth rotary joint is driveable by the second rotary joint using a fourth band mechanism. At least one of the first band mechanism, the second band mechanism, the third band mechanism, and the fourth band mechanism has a variable transmission ratio. The aforementioned aspects and other features will be described in the following description, with reference to the attached drawings. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a top view of the conveying device.

[0009] [Figure 2] Figure 2 is a top view of the conveying device.

[0010] [Figure 3] Figure 3 is a side view of the conveying device.

[0011] [Figure 4] Figure 4 is a top view of the conveying device.

[0012] [Figure 5] Figure 5 is a top view of the conveying device.

[0013] [Figure 6] Figure 6 is a top view of the conveying device.

[0014] [Figure 7] Figure 7 is a top view of the conveying device.

[0015] [Figure 8] Figure 8 is a top view of the conveying device.

[0016] [Figure 9] Figure 9 is a side view of the conveying device.

[0017] [Figure 10] Figure 10 is a top view of the conveying device.

[0018] [Figure 11] Figure 11 is a top view of the conveying device.

[0019] [Figure 12] Figure 12 is a side view of the conveying device.

[0020] [Figure 13] Figures 13A to 13C are top views of the conveying device.

[0021] [Figure 14A] Figure 14A is a top view of the conveying device.

[0022] [Figure 14B] Figure 14B is a side view of the conveying device.

[0023] [Figure 15] Figures 15A and 15C are top views of the conveying device.

[0024] [Figure 16] Figure 16 is a top view of the conveying device.

[0025] [Figure 17] Figure 17 is a side view of the conveying device.

[0026] [Figure 18A] Figure 18A is a top view of the conveying device.

[0027] [Figure 18B] Figure 18B is a side view of the conveying device.

[0028] [Figure 19] Figures 19A and 19C are top views of the conveying device.

[0029] [Figure 20] Figures 20A and 20C are top views of the conveying device.

[0030] [Figure 21] Figures 21A and 21C are top views of the conveying device.

[0031] [Figure 22] Figure 22 is a side view of the conveying device.

[0032] [Figure 23] Figure 23A is a side view of the conveying device.

[0033] Figure 23B is a side view of the conveying device.

[0034] [Figure 24] Figure 24 is a side view of the conveying device.

[0035] [Figure 25] Figure 25A is a top view of the conveying device.

[0036] Figure 25B is a side view of the conveying device.

[0037] [Figure 26] Figures 26A to 26C are top views of the conveying device.

[0038] [Figure 27] Figures 27A and 27C are top views of the conveying device.

[0039] [Figure 28] Figures 28A to 28C are top views of the conveying device.

[0040] [Figure 29A] Figure 29A is a top view of the conveying device.

[0041] [Figure 29B] Figure 29B is a side view of the conveying device.

[0042] [Figure 30] Figure 30A is a side view of the conveying device.

[0043] Figure 30B is a side view of the conveying device.

[0044] [Figure 31] Figure 31 is a top view of the conveying device.

[0045] [Figure 32]Figure 32 is a side view of the conveying device.

[0046] [Figure 33A] Figure 33A is a top view of the conveying device.

[0047] [Figure 33B] Figure 33B is a side view of the conveying device.

[0048] [Figure 34] Figures 34A to 34C are top views of the conveying device.

[0049] [Figure 35] Figures 35A and 35C are top views of the conveying device.

[0050] [Figure 36] Figure 36 is a side view of the conveying device.

[0051] [Figure 37A] Figure 37A is a top view of the conveying device.

[0052] [Figure 37B] Figure 37B is a side view of the conveying device.

[0053] [Figure 38A] Figure 38A is a top view of the conveying device.

[0054] [Figure 38B] Figure 38B is a side view of the conveying device.

[0055] [Figure 39] Figure 39 is a top view of the conveying device.

[0056] [Figure 40] Figure 40 is a side view of the conveying device.

[0057] [Figure 41A] Figure 41A is a top view of the conveying device.

[0058] [Figure 41B] Figure 41B is a side view of the conveying device.

[0059] [Figure 42A] Figure 42A is a partial outline view of the pulley.

[0060] [Figures 42B-42E] Figures 42B to 42E are top views of the conveying device.

[0061] [Figure 43] Figure 43 is a partial outline view of the pulley.

[0062] [Figure 44] Figure 44 is a top view of the conveying device.

[0063] [Figure 45] Figure 45 shows the trajectory of the shaft position.

[0064] [Figure 46] Figure 46 is a top view of the conveying device.

[0065] [Figure 47] Figure 47 shows the trajectory of the shaft position.

[0066] [Figure 48] Figure 48 is a side view of the conveying device.

[0067] [Figure 49A] Figure 49A is a top view of the conveying device.

[0068] [Figure 49B] Figure 49B is a side view of the conveying device.

[0069] [Figure 50] Figure 50 is a top view of the conveying device.

[0070] [Figure 51] Figure 51 is a diagram of the shaft's trajectory.

[0071] [Figure 52] Figure 52 is a top view of the conveying device.

[0072] [Figure 53] Figure 53 is a diagram of the shaft's trajectory. Detailed description of the examples

[0073] Referring to Figure 1, a top view of a transport device 10 having features of an exemplary embodiment is shown. These features will be described with reference to the exemplary embodiment shown in the drawings, but it should be understood that they can also be realized by various other embodiments. Furthermore, any suitable size, shape, or type of elements and materials can be used. This specification discloses a multilink robotic arm mechanism. For example, a three-link robotic arm mechanism is disclosed that can be used to transport materials to and from parallel, for example, laterally offset stations in a semiconductor wafer processing tool.

[0074] An exemplary arrangement of the semiconductor wafer processing tool 10 is schematically shown in the top view of Figure 1. In this particular example, the tool features four sets of parallel stations, for example, one set of load locks 12 and three sets of process module stations 14, 16, and 18. As shown in the example of Figure 1, the three-link arm mechanism is designed to access each station in the tool along a predefined path, for example, a substantially linear path, in a predefined orientation of the end effector, for example, along a linear path 20. These linear paths may be parallel to each other or at angles to each other in any plane 22. In another embodiment, any suitable path or combination of paths may be defined, which may be linear, circular, or any suitable shape or combination of shapes.

[0075] Figure 2 shows a top view of a robot arm mechanism 30 according to the disclosed embodiment, mounted on a robot drive unit 32, and Figure 3 shows a side view thereof. This arm mechanism may consist of a first link (upper arm) 34, a second link (forearm) 36, and a third link (end effector) 38 supporting a substrate 40. An exemplary internal mechanism of a robot 28 is schematically shown in Figure 3. This arm mechanism may be driven by a two-axis spindle having two coaxial shafts, for example, an outer T1 shaft 42 and an inner T2 shaft 44. The inner T2 shaft 44 may be partially inside the outer T1 shaft 42 so that the inner T2 shaft 44 is rotatable within the outer T1 shaft 42. The first link 34 of the robot arm mechanism may be directly attached to the T1 shaft 42. The second link 36 may be coupled to the first link 34 via a rotary joint 46 and driven by the T2 shaft 44 using a band mechanism 48. The band mechanism 48 may comprise a shoulder pulley 50, an elbow pulley 52, and a band, belt, or cable 54. The shoulder pulley 50 may be attached to the T2 shaft 44, the elbow pulley 52 may be attached to the second link 36, and the band, belt, or cable 54 may transmit motion between the two pulleys 50, 52. This belt mechanism may feature a constant transmission ratio, for example, a 1:1 ratio may be used for convenience. However, any other suitable mechanism may be used. The third link 38 may be coupled to the second link 36 via a rotary joint 56, and the orientation of the third link 38 may be constrained by another band mechanism 58. The band mechanism 58 may comprise an elbow pulley 60, a wrist pulley 62, and a band, belt, or cable 64. The elbow pulley 60 may be connected to the first link 34, and the wrist pulley 62 may be connected to the third link 38, and a band, belt, or cable 64 may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figure 3 as an example, the wrist pulley may feature a non-circular shape.An example of an arm using a non-circular pulley is disclosed in U.S. Patent Application No. 13 / 833,732, titled "Robot Having Arm With Unequal Link Lengths," filed March 15, 2013. This reference is incorporated in its entirety by reference.

[0076] The variable transfer ratio may be selected to change the orientation of the third link (end effector) 38 in a predefined manner as a function of the relative positions of the first link 34 and the second link 36. The relative positions of the first link 34 and the second link 36 may be conveniently expressed as the narrow angle between the two links. Alternatively, the orientation of the third link (end effector) 38 may be changed in a predefined manner as a function of the relative positions of the links, shafts, etc. For example, the transfer ratio may be selected so that, when the first and second links are driven, the reference point on the third link (usually the nominal center 70 of the end effector) follows a predefined path while maintaining a predefined (but not necessarily constant) orientation of the third link (end effector). For example, as shown in Figure 4, paths 72, 74, 76, and 78 may be selected as access paths to any of the stations in Figure 1. Alternatively, as shown in Figure 5, the transfer ratio may be selected so that the arm can access the adjacent station 82. As shown in Figures 6 and 7, the T1 shaft 42 and T2 shaft 44 may be rotated to change the orientation of the arm mechanism to access another set of stations 86, 88, or 90, 92.

[0077] The initial position of the robot arm mechanism is shown on the axis of symmetry between adjacent parallel stations, but it should be noted that any other arbitrary initial position may be used. Furthermore, the robot's drive system may feature additional axes to facilitate the vertical elevation of the arm mechanism, for example, lifting and positioning wafers transported by the end effector. In another embodiment, other additional rotation axes and / or arms may be provided. In another embodiment, a variable transmission ratio is characterized in the band mechanism between the shoulder pulley attached to the T2 shaft and the elbow pulley attached to the second link, for example, using at least one non-circular pulley. The variable transmission ratio is selected such that the extension of the arm is driven by the T1 shaft and the T2 shaft remains stationary. In another embodiment, the variable transmission ratio may be selected such that the T2 shaft follows a predefined motion profile as the robot arm extends along a predefined path. In another embodiment, the mechanism constraining the orientation of the third link includes an additional band mechanism.

[0078] For example, as schematically shown in Figure 8, the orientation of the third link 102 may be constrained by a band mechanism 104. The band mechanism 104 may comprise an elbow pulley 106, a wrist pulley 114, and a band, belt, or cable 116. The elbow pulley 106 may be coaxial with the elbow joint 108 (the rotational joint between the first and second links) and may rotate freely relative to the two links, the first link 110 and the second link 112. The wrist pulley 114 may be connected to the third link 102. The band, belt, or cable 116 may transmit motion between the two pulleys. The motion of the elbow pulley is constrained by another band mechanism 118. The band mechanism 118 may comprise a pulley 120, a pulley 124, and a band, belt, or cable 126. Pulley 120 is attached to the T2 shaft 122, and pulley 124 is attached to the elbow pulley 106, and a band, belt, or cable 126 may transmit motion between these two pulleys. The two band mechanisms may feature a constant or variable transmission ratio. For example, if the two band mechanisms feature a constant ratio of 1:1 and the second link is coupled to the T2 shaft, the end effector maintains a constant orientation as the arm extends and retracts due to the drive of the T1 shaft.

[0079] The disclosed embodiments are also applicable to dual-end effector arm mechanisms that may be used for material transport to and from parallel (laterally offset) stations in a semiconductor wafer processing tool. Here, an exemplary arrangement of the semiconductor wafer processing tool 210 is schematically shown in the top view of Figure 10. In this particular example, the tool features four sets of parallel stations, for example, one set of load locks 220, three sets of process module stations 230, and a transport chamber or module 232.

[0080] As shown in the example in Figure 10, the arm mechanism of this embodiment may be designed to access each station in the tool along a predefined path 236, for example, a substantially straight path, with a predefined orientation of the end effector, for example, an orientation along the straight path.

[0081] Figure 11 shows a top view of a robot arm mechanism 250 attached to a robot drive unit 252, and Figure 12 shows a side view thereof. This arm mechanism may consist of a first link (upper arm) 254, a second link (forearm) 256, a pivot end effector A 258, and a pivot end effector B 260. An exemplary internal mechanism of the robot is schematically shown in Figures 11 and 12. This arm mechanism may be driven by a three-axis spindle having three coaxial shafts, for example, an outer T1 shaft 262, a T2 shaft 264, and an inner T3 shaft 266. The T2 shaft 264 may be partially inside the outer T1 shaft 262, and the inner T3 shaft 266 may be partially inside the T2 shaft 264. The first link of the robot arm mechanism may be directly attached to the T1 shaft. The second link may be coupled to the first link via a rotary joint (elbow joint) and driven by the T3 shaft using a band mechanism. This band mechanism may comprise a first shoulder pulley, a first elbow pulley, and a band, belt, or cable. The first shoulder pulley may be attached to the T3 shaft, and the first elbow pulley may be attached to the second link, and the band, belt, or cable may transmit motion between these two pulleys. This band mechanism may feature a constant or variable transmission ratio, for example, a 1:1 ratio may be used for convenience. However, any other suitable mechanism may be used. The end effector A may be coupled to the second link via a rotary joint (wrist joint), and the orientation of the end effector A may be controlled by a two-stage band mechanism. The first stage of this band mechanism may comprise a second shoulder pulley, a second elbow pulley, and a band, belt, or cable. The second shoulder pulley may be connected to the T2 shaft, and the band, belt, or cable may transmit motion between these two pulleys. The first stage of this band mechanism may feature a constant or variable transmission ratio, for example, a 1:1 ratio may be used for convenience. The second stage of the band mechanism may comprise a third elbow pulley, a first wrist pulley, and a band, belt, or cable.A third elbow pulley may be connected to a second elbow pulley, and a first wrist pulley may be connected to an end effector A, and a band, belt, or cable may transmit motion between these two pulleys. The second stage of this band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figures 11 and 12, the wrist pulley may feature a non-circular shape. An example of an arm using non-circular pulleys is disclosed in U.S. Patent Application No. 13 / 833,732, “Robot Having Arm With Unequal Link Lengths,” filed March 15, 2013. This reference is incorporated in whole by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 132,066, titled "2-Degree-of-Freedom 3-Link Robot Arm Mechanisms," filed March 12, 2015. This reference is incorporated in its entirety by reference.

[0082] The variable transfer ratio may be selected to change the orientation of end effector A in a predefined manner as a function of the relative positions of the first link, the second link, and the T2 shaft. For example, the variable transfer ratio may be selected so that end effector A follows a path to the station, as shown in Figures 13A to 13C, or so that it folds laterally in response to the movement of the T2 shaft, also as shown in Figures 13A to 13C. Similarly, end effector B may be coupled to the second link via a rotary joint (wrist joint), and the orientation of end effector B may be controlled by a two-stage band mechanism. The first stage of this band mechanism is common to end effector A. The second stage of this band mechanism may comprise a fourth elbow pulley, a second wrist pulley, and a band, belt, or cable. The fourth elbow pulley may be connected to the second elbow pulley, and the second wrist pulley may be connected to end effector B, and the band, belt, or cable may transmit motion between these two pulleys. The second stage of this band mechanism may be configured in a cross shape as shown in Figures 11 and 12, and may feature a variable transmission ratio. The variable transmission ratio may be realized, for example, using at least one pulley having a non-circular shape. Referring to Figures 11 and 12, the wrist pulley may feature a non-circular shape. The variable transmission ratio may be selected to change the orientation of the end effector B in a predefined manner as a function of the relative position of the first link, the second link, and the T2 shaft. For example, the variable transmission ratio may be selected so that the end effector B follows a path to the station, as shown in Figures 13A to 13C, or so that it folds laterally in response to the motion of the T2 shaft, also as shown in Figures 13A to 13C.

[0083] In Figures 13A to 13C, the arm mechanism is shown as right-handed when accessing the left-side station (the elbow joint is located to the right of the line from the shoulder joint to the wrist joint), and as left-handed when accessing the right-side station. However, in another embodiment, the mechanism may be configured to be left-handed when accessing the left-side station and right-handed when accessing the right-side station.

[0084] In yet another embodiment, the second link may be driven by the T2 shaft, and the orientation of the end effector may be controlled by the T3 shaft. Referring to Figures 14A and 14B, a top view and a side view, respectively, of the robot arm mechanism 300 attached to the robot drive unit 302 are shown. An exemplary internal mechanism of the robot is also included. The arm mechanism may consist of a left linkage 304 and a right linkage 306. This arm mechanism may be driven by a three-axis spindle having three coaxial shafts, for example, an outer T1 shaft 308, a T2 shaft 310, and an inner T3 shaft 312. The T2 shaft 310 may be partially inside the outer T1 shaft 308, and the inner T3 shaft 312 may be partially inside the T2 shaft 310. The left linkage may consist of a first left link (upper arm) 314, a second left link (forearm) 316, and a third left link (end effector) 318. The first left link may be directly attached to the T1 shaft. The second left-side link may be coupled to the first left-side link via a rotary joint and constrained by the T2 shaft using a band mechanism. This band mechanism may comprise a first shoulder pulley, a left elbow pulley, and a band, belt, or cable. The first shoulder pulley may be attached to the T2 shaft, and the left elbow pulley may be attached to the second link, and the band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. However, any other suitable mechanism may be used. The third left-side link may be coupled to the second left-side link via a rotary joint, and the orientation of the third left-side link may be constrained by another band mechanism. This band mechanism may comprise a left elbow pulley, a left wrist pulley, and a band, belt, or cable. The left elbow pulley may be connected to the first left-side link, and the left wrist pulley may be attached to the third left-side link, and the band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape.As an example, referring to Figures 14A and 14B, the wrist pulley may feature a non-circular shape. The variable transmission ratio may be selected to change the orientation of the third left link (end effector) in a predefined manner as a function of the relative positions of the first left link and the second left link. The relative positions of the first and second left links may be conveniently expressed as the narrow angle between the two links. For example, the transmission ratio of the two band mechanisms may be selected so that, when the first left link is driven by the T1 shaft and the T2 shaft remains stationary, the reference point on the third left link (usually the nominal center of the end effector) follows a predefined path, while maintaining a predefined (e.g., constant) orientation of the third left link (end effector).

[0085] For example, as shown in Figures 15A to 15C, a route may be selected as an access route to one of the stations in Figure 10. Referring again to Figures 14A and 14B, the right-side linkage may be substantially configured as a mirror image of the left-side linkage. The right-side linkage may consist of a first right-side link (upper arm) 320, a second right-side link (forearm) 322, and a third right-side link (end effector) 324. The first right-side link may be directly attached to the T3 shaft. The second right-side link may be coupled to the first right-side link via a rotary joint and constrained by the T2 shaft using a band mechanism. This band mechanism may comprise a second shoulder pulley, a right elbow pulley, and a band, belt, or cable. The second shoulder pulley may be attached to the T2 shaft, and the right elbow pulley may be attached to the second link, and the band, belt, or cable may transmit motion between these two pulleys. Similar to the left-side linkage, the belt mechanism may feature a variable transmission ratio. However, any other suitable mechanism may be used.

[0086] The remaining components of the right linkage may be substantially configured as a mirror image of the left linkage, and the operation of the right linkage is substantially equivalent to that of a mirror image of the left linkage. Furthermore, the T1, T2, and T3 shafts may be rotated synchronously to change the orientation of the arm mechanism and allow access to another set of stations.

[0087] In Figures 15A to 15C, the left linkage is shown as left-handed (the elbow joint is located to the left of the line from the shoulder joint to the wrist joint), and the right linkage is shown as right-handed. However, in another embodiment, this mechanism may be configured such that the left linkage is right-handed and the right linkage is left-handed.

[0088] In yet another embodiment, the right upper arm may be driven by the T2 shaft, and the orientation of the left and right forearms may be restricted by the T3 shaft.

[0089] The disclosed embodiments are also applicable to a dual-end effector robotic arm mechanism which may be used for material transfer to and from parallel (laterally offset) stations in a semiconductor wafer processing tool. An exemplary arrangement of the semiconductor wafer processing tool 410 is schematically shown in the top view of Figure 16. In this particular example, the tool features four sets of parallel stations, for example, one set of load locks 412 and three sets of process module stations 414 coupled to a transfer chamber 416.

[0090] As shown in the example in Figure 16, the disclosed arm mechanism may access each station in the tool along a predefined path, for example, substantially straight paths 418, 420, and in a predefined orientation of the end effector, for example, an orientation along the straight paths 418, 420.

[0091] Figure 17 shows a side view of a robot 50 having an exemplary robot arm mechanism 452 according to one embodiment, mounted on a robot drive unit 454. This arm mechanism may consist of a first link (upper arm) 456, a second link (forearm) A458, an end effector A460, a second link (forearm) B462, and an end effector B464. An exemplary internal mechanism of the robot 450 of Figure 17 is schematically shown in Figures 18A and 18B. This arm mechanism may be driven by a three-axis spindle 454 having three coaxial shafts, for example, an outer T1 shaft 470, a T2 shaft 472, and an inner T3 shaft 474. The first link 456 of the robot arm mechanism may be directly attached to the T1 shaft 470. The second link A458 may be coupled to the first link 456 via a rotary joint (elbow joint) 480 and driven by the T3 shaft 474 using a band mechanism 482. The band mechanism 482 may comprise a shoulder pulley A484, an elbow pulley A486, and a band, belt, or cable 488. The shoulder pulley A484 may be attached to the T3 shaft 474, and the elbow pulley A486 may be attached to the second link A458, and the band, belt, or cable 488 may transmit motion between these two pulleys. The band mechanism may feature a constant or variable transmission ratio, for example, a 1:1 ratio may be used for convenience. However, any other suitable mechanism may be used. Similarly, the second link B462 may be coupled to the first link 456 via a rotary joint (elbow joint) 480 and driven by the T2 shaft 472 using a band mechanism 483. The end effector A460 may be coupled to the second link A458 via a rotary joint (wrist joint) 490, and the orientation of the end effector A460 may be constrained by another band mechanism 492. The band mechanism may comprise an elbow pulley 494, a wrist pulley 496, and a band, belt, or cable 498. The elbow pulley 494 may be connected to a first link, the wrist pulley 496 may be connected to an end effector A460, and the band, belt, or cable 498 may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio.The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. For example, referring to Figures 18A and 18B, the wrist pulley may feature a non-circular shape. An example of an arm using a non-circular pulley is disclosed in U.S. Patent Application No. 13 / 833,732 (titled "Robot Having Arm With Unequal Link Lengths," filed March 15, 2013). This reference is incorporated in its entirety by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 132,066 (titled "2-Degree-of-Freedom 3-Link Robot Arm Mechanisms," filed March 12, 2015). This reference is incorporated in its entirety by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 135,490, titled "Arm Mechanisms with Two End Effectors," filed March 19, 2015. This reference is incorporated in its entirety by reference.

[0092] The variable transfer ratio may be selected to change the orientation of the end effector A460 in a predefined manner as a function of the relative positions of the first link 456 and the second link A458. For example, the variable transfer ratio may be selected so that the end effector A460 follows a path to the station, as shown in Figures 19A to 19C.

[0093] Similarly, the end effector B464 may be coupled to a second link B462 via a rotary joint (wrist joint) 502, and the orientation of the end effector B464 may be further constrained by another band mechanism 504. The band mechanism 504 may comprise an elbow pulley 506, a wrist pulley 508, and a band, belt, or cable 510. The elbow pulley 506 may be connected to the first link 456, and the wrist pulley 508 may be connected to the end effector B464, and the band, belt, or cable 510 may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figures 18A and 18B as an example, the wrist pulley may feature a non-circular shape. The variable transfer ratio may be selected as a function of the relative positions of the first link and the second link B to change the orientation of the end effector B in a predefined manner. For example, the variable transfer ratio may be selected so that the end effector B follows a path to the station, as shown in Figures 19A to 19C.

[0094] Typical operation of this robot is shown in Figures 19 to 21. Figures 19A to 19C show robot 450 in a retracted position, accessing the left station 530 via end effector A and the same station via end effector B. This allows the robot to perform rapid material changes at the left station. Similarly, Figures 20A to 20C show robot 450 accessing station B 532 via end effectors A and B. This allows the robot to perform rapid material changes at station B. Finally, Figures 21A to 21C show that the robot may extend both end effectors 460 and 464 to access the left station 530 and the right station 532 simultaneously. Furthermore, the T1, T2, and T3 shafts may be rotated synchronously to change the orientation of the arm mechanism to access another set of stations or any suitable combination of locations.

[0095] Examples in Figures 17 to 21 show a robot arm mechanism having multiple coaxially configured elbow joints. However, as schematically shown in the exemplary robot 450' of Figure 22, these elbow joints may be configured as two separate joints 542, 544 offset 540. Further exemplary embodiments are schematically shown in Figures 23A and 23B. Figure 23A shows a robot 600 comprising a drive unit 602, a common upper arm 604, a forearm A 606, and a forearm B 608. Forearms A 606 and B 608 have a common elbow 610. Here, robot 600 includes an end effector mounted on the upper surface of forearm 608 at the wrist joint and an end effector mounted on the upper surface of forearm 606 at the wrist joint. This robot 600 may be driven and used in a similar manner to robot 450. Figure 23B shows a robot 600' comprising a drive unit 602, a common upper arm 604, a forearm A606', and a forearm B608. Forearms A606' and B608 share a common elbow 610. Here, robot 600' includes an end effector mounted on the upper surface of forearm 608 at the wrist joint, and an end effector mounted on the lower surface of forearm 606' at the wrist joint. This robot 600' may be driven and used in the same manner as robot 450.

[0096] Figure 24 shows a side view of a robot equipped with a robot arm mechanism 702 according to one embodiment, mounted on a robot drive unit 704. This arm mechanism may consist of linkage A 706 and linkage B 708. An exemplary internal mechanism of the robot 700 of Figure 24 is schematically shown in Figures 25A and 25B. This arm mechanism may be driven by a three-axis spindle 704 having three coaxial shafts, for example, an outer T1 shaft 710, a T2 shaft 712, and an inner T3 shaft 714. The T2 shaft 712 may be partially inside the outer T1 shaft 710, and the inner T3 shaft 714 may be partially inside the T2 shaft 712. Linkage A 706 may consist of a first link (upper arm) 716, a second link (forearm) 718, and a third link (end effector A) 720. The first link may be directly attached to the T3 shaft 714. The second link may be coupled to the first link via a rotary joint 722 and constrained by the T2 shaft 712 using a band mechanism 724. The band mechanism 724 may comprise a shoulder pulley, an elbow pulley, and a band, belt, or cable. The shoulder pulley may be attached to the T2 shaft 712, and the elbow pulley may be attached to the second link 718, and the band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. However, any other suitable mechanism may be used. The third link 720 of linkage A may be coupled to the second link 718 via a rotary joint 726, and the orientation of the third link 720 may be constrained by another band mechanism 728. The band mechanism 728 may comprise a right elbow pulley, a wrist pulley, and a band, belt, or cable. The right elbow pulley may be connected to the first link 716, and the wrist pulley may be connected to the third link 720, and a band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figures 25A and 25B as an example, the wrist pulley may feature a non-circular shape.The variable transfer ratio may be selected to change the orientation of the third link (end effector A) of linkage A in a predefined manner, as a function of the relative positions of the first and second links. The relative positions of the first and second links may be conveniently expressed as the narrow angle between the two links. For example, the transfer ratio of the two band mechanisms of linkage A706 may be selected so that, when the first link is driven by the T3 shaft and the T2 shaft remains stationary, the reference point on the third link (usually the nominal center of end effector A) follows a predefined path, while maintaining a predefined (e.g., constant) orientation of the third right-hand link (end effector A).

[0097] For example, as shown in Figures 26A to 26C, a route may be selected as an access route to any of the stations in Figure 16. Referring again to Figures 25A and 25B, linkage B708 ​​may consist of a first link (upper arm) 732, a second link 734 (forearm), and a third left-side link (end effector B) 736. The first link 732 may be directly attached to the T1 shaft 710. The second link 734 may be coupled to the first link 732 via a rotary joint 738 and constrained by the T2 shaft 712 using a band mechanism 740. This band mechanism may comprise another shoulder pulley, an elbow pulley, and a band, belt, or cable. The other shoulder pulley may be attached to the T2 shaft 712, and the elbow pulley may be attached to the second link 734, and the band, belt, or cable may transmit motion between these two pulleys. Similar to the right-side linkage A, the band mechanism may feature a variable transmission ratio. However, any other suitable mechanism may be used. The remaining components of linkage B may be configured in the same way as linkage A, and the operation of linkage B is substantially equivalent to the operation of linkage A, except that the T1 shaft 710 plays the role of the T3 shaft 714.

[0098] Typical operation of this robot is shown in Figures 26 to 28. Figures 26A to 26C show the robot 700 in a retracted position accessing the left station 532 via end effector A720 and the same station via end effector B736. This allows the robot 700 to perform rapid material changes at the left station 532. Similarly, Figures 27A to 27C show the robot 700 accessing station 534 via end effectors A720 and B736. This allows the robot to perform rapid material changes at station 534. Furthermore, Figures 28A to 28C show that the robot may extend both end effectors to access the left and right stations simultaneously. Additionally, the T1, T2, and T3 shafts may be rotated synchronously to change the orientation of the arm mechanism to access another set of stations or any suitable position.

[0099] Alternatively, as shown in Figures 29A and 29B, the arm mechanism may be driven by a four-axis spindle 750 comprising four coaxial shafts, for example, an outer T1 shaft 752, a T2 shaft 754, a T3 shaft 756, and an inner T4 shaft 758, as shown in the example in Figure 29. In this particular example, the T1 shaft 752 may be connected to the first link 760 of linkage A, the T2 shaft 754 may drive the second link 762 of linkage A, the T3 shaft 756 may drive the second link 764 of linkage B, and the T4 shaft 758 may be connected to the first link 766 of linkage B. However, any suitable configuration of the four shafts may be used.

[0100] Further exemplary embodiments are schematically shown in Figures 30A and 30B. Figure 30A shows a robot 780 comprising a drive unit 782 and nested arms A784 and B786 as shown. Robot 780 has similar features to robots 700, 750, etc., and may be driven in the same manner. Here, robot 780 comprises an end effector mounted at the wrist joint on the upper surface of one forearm and an end effector mounted at the wrist joint on the upper surface of the other forearm. This robot 780 may be driven and used in the same manner as other robots. Figure 30B shows a robot 780' comprising a drive unit 782 and nested arms A784' and B786 as shown. Robot 780' has similar features to robots 700, 750, etc., and may be driven in the same manner. Here, robot 780' comprises an end effector mounted at the wrist joint on the upper surface of one forearm and an end effector mounted at the wrist joint on the lower surface of the other forearm. This robot 780' may be driven and used in the same way as other robots.

[0101] The disclosed embodiments are also applicable to dual-end effector robotic arm mechanisms that may be used for material transfer to and from parallel (laterally offset) stations in a semiconductor wafer processing tool. An exemplary arrangement of the semiconductor wafer processing tool 810 is schematically shown in the top view of Figure 31. In this particular example, the tool features four sets of parallel stations, for example, one set of load locks 812 and three sets of process module stations 814 coupled to a transfer chamber 816.

[0102] As shown in the example in Figure 31, the arm mechanism may access each station in the tool along a predefined path, for example, substantially straight paths 818, 820, and in a predefined orientation of the end effector, for example, in an orientation along the straight paths 818, 820.

[0103] Figure 32 shows a side view of a robot 850, which includes an exemplary robot arm mechanism 852 according to one embodiment, mounted on a robot drive unit 854. This arm mechanism may consist of a first link (upper arm) 856, a second link (forearm) A858, an end effector A860, a second link (forearm) B862, and an end effector B864. An exemplary internal mechanism of the robot 850 of Figure 32 is schematically shown in Figures 33A and 33B. This arm mechanism may be driven by a three-axis spindle 854 having three coaxial shafts, for example, an outer T1 shaft 870, a T2 shaft 872, and an inner T3 shaft 874. The first link 856 of the robot arm mechanism may be directly attached to the T1 shaft 870. The second link A858 may be coupled to the first link 856 via a rotary joint (elbow joint) 880 and driven by the T3 shaft 874 using a band mechanism 882. The band mechanism 882 may comprise a shoulder pulley A884, an elbow pulley A886, and a band, belt, or cable 888. The shoulder pulley A884 may be attached to the T3 shaft 874, and the elbow pulley A886 may be attached to the second link A858, and the band, belt, or cable 888 may transmit motion between these two pulleys. The band mechanism may feature a constant or variable transmission ratio, for example, a 1:1 ratio may be used for convenience. However, any other suitable mechanism may be used. Similarly, the second link B862 may be coupled to the first link 856 via a rotary joint (elbow joint) 880 and driven by the T2 shaft 872 using the band mechanism 883. The end effector A860 may be coupled to the second link A858 via a support structure 861 and a rotary joint (wrist joint) 890. As shown in the example in Figure 32, the support structure 861 may be attached to the rotary joint 890 below the second link A858 and may be shaped to avoid mechanical interference with, for example, the second link A858 and the second link B862 during operation. The support structure 861 may be formed by one or more components integrated with the end effector A860 or the rotary joint 890, or implemented in any other suitable manner.The orientation of the end effector A860 may be constrained by a band mechanism 892. This band mechanism may comprise an elbow pulley 894, a wrist pulley 896, and a band, belt, or cable 898. The elbow pulley 894 may be connected to a first link, and the wrist pulley 896 may be connected to a support structure 861 comprising the end effector A860, and the band, belt, or cable 898 may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figures 33A and 33B as an example, the wrist pulley may feature a non-circular shape. An example of an arm using a non-circular pulley is disclosed in U.S. Patent Application No. 13 / 833,732 (titled "Robot Having Arm With Unequal Link Lengths," filed March 15, 2013). This reference is incorporated into this application in its entirety by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 132,066 (titled "2-Degree-of-Freedom 3-Link Robot Arm Mechanisms," filed March 12, 2015). This reference is incorporated into this application in its entirety by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 135,490 (titled "Arm Mechanisms with Two End Effectors," filed March 19, 2015). This reference is incorporated in its entirety by reference. Another example of an arm using a non-circular pulley is disclosed in U.S. Provisional Patent Application No. 62 / 137,458, titled "Robot Arm Mechanisms with Two End Effectors," filed March 24, 2015. This reference is incorporated in its entirety by reference.

[0104] The variable transfer ratio may be selected to change the orientation of the end effector A860 in a predefined manner as a function of the relative positions of the first link 856 and the second link A858. For example, the variable transfer ratio may be selected so that the end effector A860 follows a path to the station, as shown in Figures 34A to 34C. The end effector B864 may be coupled to the second link B862 via a rotary joint (wrist joint) 902, and the orientation of the end effector B864 may be further constrained by another band mechanism 904. The band mechanism 904 may comprise an elbow pulley 906, a wrist pulley 908, and a band, belt, or cable 910. The elbow pulley 906 may be connected to the first link 856, and the wrist pulley 908 may be connected to the end effector B864, and the band, belt, or cable 910 may transmit motion between these two pulleys. The band mechanism may feature a variable transfer ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. Referring to Figures 33A and 33B as an example, the wrist pulley may feature a non-circular shape.

[0105] The variable transfer ratio may be selected to change the orientation of end effector B in a predefined manner as a function of the relative positions of the first link and the second link B. For example, the variable transfer ratio may be selected so that end effector B follows a path to the station, as shown in Figures 34A to 34C. Typical operation of this robot is shown in Figures 34 and 35. Figures 34A to 34C show robot 850 in a retracted position in front of the left station 530, accessing the left station 530 via end effector A and then accessing the same station via end effector B. This allows the robot to perform rapid material exchange at the left station. Referring further to Figures 34A to 34C, end effector A860 may be extended to the left station 530 along a desired path, for example, a substantially straight path 820. This is done by rotating the T3 shaft 874 clockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T3 shaft 874, so that the end effector A860 follows the desired straight path 820. At the same time, the T2 shaft 872 may be rotated synchronously with the T1 shaft 870 so that the end effector B864 remains folded on the second link B862. Similarly, the end effector A860 may be retracted from the left station 530 along a desired path, for example, the same substantially straight path 820. This is done by rotating the T3 shaft 874 counterclockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T3 shaft 874, so that the end effector A860 follows the desired straight path 820. Here again, the end effector B864 may remain folded on the second link B862 by rotating the T2 shaft 872 in sync with the T1 shaft 870. Next, the end effector B864 may be extended to the left station 530 along a desired path, for example, a substantially straight path 820. This is done by rotating the T2 shaft 872 clockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T2 shaft 872 so that the end effector B864 follows the desired straight path 820.Simultaneously, the end effector A860 may remain folded on the second link A858 by rotating the T3 shaft 874 in synchronous manner with the T1 shaft 870. Furthermore, the end effector B864 may be retracted from the left station 530 along a desired path, for example, the same substantially straight path 820. This is done by rotating the T2 shaft 872 counterclockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T2 shaft 872 so that the end effector B864 follows the desired straight path 820. Again, the end effector A860 may remain folded on the second link A858 by rotating the T3 shaft 874 in synchronous manner with the T1 shaft 870. Furthermore, the T1, T2, and T3 shafts may be rotated in synchronous manner to change the orientation of the arm mechanism to access another location, for example, the right station 532.

[0106] Figures 35A to 35C show the robot 850 accessing the right-side station 532 via end effectors A and B. This allows the robot to perform rapid material changes at the right-side station 532. In Figures 35A to 35C, the end effector A860 may be extended to the right-side station 532 along a desired path, for example, a substantially straight path 818. This is done by rotating the T3 shaft 874 counterclockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T3 shaft 874 so that the end effector A860 follows the desired straight path 818. At the same time, the end effector B864 may remain folded on the second link B862 by rotating the T2 shaft 872 in synchronous motion with the T1 shaft 870. Similarly, the end effector A860 may be retracted from the right-side station 532 along a desired path, for example, the same substantially straight path 818. This is done by rotating the T3 shaft 874 clockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T3 shaft 874 so that the end effector A860 follows the desired straight path 818. Here again, the end effector B864 may remain folded on the second link B862 by rotating the T2 shaft 872 in synchronous with the T1 shaft 870. Next, the end effector B864 may be extended to the right-hand station 532 along the desired path, for example, a substantially straight path 818. This is done by rotating the T2 shaft 872 counterclockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T2 shaft 872 so that the end effector B864 follows the desired straight path 818. Simultaneously, the end effector A860 may remain folded on the second link A858 by rotating the T3 shaft 874 in synchronous manner with the T1 shaft 870. Furthermore, the end effector B864 may be retracted from the right-side station 532 along a desired path, for example, the same substantially straight path 818. This is done by rotating the T2 shaft 872 clockwise and coordinating the rotation of the T1 shaft 870 with the rotation of the T2 shaft 872 so that the end effector B864 follows the desired straight path 818.Here too, by rotating the T3 shaft 874 in sync with the T1 shaft 870, the end effector A860 may remain folded on the second link A858.

[0107] The actions and movements shown in Figures 34 and 35 are examples, and the arm mechanism may perform other desired actions and appropriate movements. For example, some or all rotations of shafts 870, 872, and 874 may be defined and coordinated so as to minimize the momentum of a retracted end effector, e.g., end effector A860, during the extension and contraction of other end effectors, e.g., end effector B864. As another example, individual movements such as extension, contraction, and rotation may be fused and / or overlapped to achieve a smooth motion path and reduce the overall duration of the movement.

[0108] Examples in Figures 32 and 33 show a robotic arm mechanism in which a support structure 861 is attached to a rotary joint 890 below a second link A858. However, the support structure 861 may be attached to the rotary joint 890 above the second link A858, as schematically shown in Figure 36. An exemplary internal mechanism of the exemplary embodiment of Figure 36 is schematically shown in Figures 37A and 37B. Alternatively, the support structure 861 may be attached to the rotary joint 90 in any suitable way and may have any suitable shape.

[0109] Examples in Figures 32 to 37 show a robotic arm mechanism with second links A858 and B862 of the same length. However, the overall length and inter-joint length of the second links A858 and B862 may be any suitable length. Similarly, in the examples in Figures 32 to 37, end effectors A860 and B864 are shown to be of the same length, but these end effectors may be of any suitable length.

[0110] The exemplary embodiments shown in Figures 32 to 37 include band mechanisms 882 and 883, but any other suitable single-stage or multi-stage transmission mechanism having a constant or variable transmission ratio may be used. This includes, but is not limited to, chains and gears. Similarly, any other suitable single-stage or multi-stage transmission mechanism having a suitable variable transmission ratio, such as chains and gears, may be used instead of band mechanisms 892 and 904. Furthermore, in any embodiment disclosed herein, chains may be used (for example, instead of or in combination with bands, belts, or cables) as well as gears.

[0111] In one example of a suitable mechanism shown in Figures 36 and 37, the robot 850' is equipped with an end effector 860' having a bridge. This bridge is mounted on the upper surface of the wrist joint, rather than the lower surface of the wrist joint, as shown in Figure 32. In another example of a suitable mechanism shown in Figures 38A and 38B, the robot 850'' is equipped with offset shoulder joints 897, 899.

[0112] An exemplary arrangement of the semiconductor wafer processing tool 1010 is schematically shown in the top view of Figure 39. In this example, the tool features four sets of parallel stations 1012, for example, one set of load locks and three sets of process module stations 1012 coupled to a transport chamber 1014. Figure 40 shows a side view of a robot 1050 having an exemplary two-degree-of-freedom, three-link robot arm mechanism 1054 mounted on a robot drive unit 1056. The arm mechanism 1054 may consist of a first link (upper arm) 1058, a second link (forearm) 1060, and a third link (end effector) 1062. An exemplary internal mechanism of the robot 1050 in Figure 40 is schematically shown in Figures 41A and 41B. This arm mechanism may be driven by a two-axis spindle 1064 having two coaxial shafts, for example, an outer T1 shaft 1066 and an inner T2 shaft 1068. As shown in Figures 41A and 41B, the orientation of the end effector 1062 may be constrained by a band mechanism 1068. The band mechanism 1068 may comprise an elbow pulley 1070, a wrist pulley 1072, and a band, belt, or cable. The elbow pulley 1070 may be connected to the first link 1058, and the wrist pulley 1072 may be connected to the end effector 1062, and the band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, by using at least one pulley having a non-circular shape. For example, referring to Figures 41A and 41B, the wrist pulley 1072 may feature a non-circular shape, and the elbow pulley 1070 may have a substantially circular shape. The variable transfer ratio may be selected as a function of the relative positions of the first and second links to change the orientation of the end effector in a predefined manner. For example, the variable transfer ratio may be selected so that the end effector follows a path to the station, as shown in Figure 39.

[0113] An exemplary mechanism having a variable transmission ratio that provides the functions described above will be described. For example, see Figures 42A to 45. The appropriate geometry of the arm mechanism, i.e., the inter-joint link length and end effector length, may be conveniently determined from the station location, the reach required for the end effector, and constraints and obstacles in the workspace (which may determine the allowable slewing radius of the arm mechanism in the retracted position).

[0114] To determine an exemplary length of the third link 1062, the following procedure is followed. The length of the third link, i.e., L3, may be conveniently defined as the distance between the axis of rotation of the wrist joint 1080 and the reference point 1082 on the third link (usually the nominal center of the end effector). There are effectively three constraints when the end effector extends to the station: 1) the position of the reference point on the third link (usually the nominal center of the end effector) must be substantially aligned with the location of the station; 2) the end effector must be oriented in the desired direction, for example, pointing in a straight line along the access path to the station; and 3) the wrist joint must be retracted sufficiently so as not to collide with any obstacles on the path to the station. The aforementioned constraints may be used, for example, as the minimum value that satisfies the constraints to determine the length of the third link (end effector). For example, the following formula may be used.

[0115] TIFF0007863144000001.tif1168

[0116] Here, X stn and Y stn These are the x-axis and y-axis offsets of the station's location in a Cartesian coordinate system centered on the robot (i.e., the robot's center (shoulder joint) is at (0,0)), and R s This defines the allowable swivel radius R, which is a circular space in which the retracted robot arm mechanism can freely rotate. s That is the case.

[0117] To determine the exemplary length of the second link, proceed as follows. The length between joints of the second link, i.e., L2, may be defined as the distance between the axis of rotation of the elbow joint and the axis of rotation of the wrist joint. In the case of a semiconductor wafer processing tool with multiple sets of parallel stations, such as the exemplary arrangement of FIG. 39, the length of the forearm may be conveniently selected to be the same as, or longer if necessary, than the offset of the location of the station from the axis of symmetry of the parallel stations, i.e., half of the distance between the locations of the stations.

[0118] TIFF0007863144000002.tif944

[0119] For the end effector of the arm mechanism to achieve the reach to the required station without overextending the elbow joint, L2 may need to be made larger than X stn in some cases.

[0120] To determine the exemplary length of the first link, proceed as follows. The length between joints of the first link, i.e., L1, may be defined as the distance between the axis of rotation of the shoulder joint and the axis of rotation of the elbow joint. Given the values of L2 and L3, the length of the first link may be determined, for example, such that when the arm mechanism is contracted, it fits within the allowable turning radius.

[0121] TIFF0007863144000003.tif975

[0122] Here, R w is the radius of a circular payload such as a wafer carried by the end effector. <00005... As an example, the x-axis offset X stn may be 388.6 mm and the y-axis offset Y stn may be 1,030.2 mm, and the location of the station may be selected. The allowable turning radius R sThis may be selected as, for example, 605.8 mm. The payload transported by the arm mechanism has a radius R, for example. w A circular wafer with a diameter of 150 mm may also be used. Based on the exemplary guidelines described above, the geometry of a suitable exemplary arm mechanism, i.e., the inter-joint link length and end effector length, is L3 = 565.5 mm, L2 = 397.6 mm > X stn It may also be determined as follows: =388.6mm and L1=287.9mm.

[0124] Consider the exemplary arm mechanism shown in Figures 40 and 41. In this arm mechanism, the orientation of the end effector may be constrained, for example, by a band mechanism comprising a circular elbow pulley and a non-circular wrist pulley. Assuming the location of the exemplary station and the geometry of the arm mechanism described above, the wrist pulley may have the outline shown by line 1102 in Figure 42A (for clarity, half of the outline is shown in the figure). The relative orientation of the wrist pulley to the third link (end effector) is indicated by the solid arrow 1104. Arrow 1104 points from the axis (center) of the wrist joint along the longitudinal axis of the third link to the center of the end effector. For comparison, a circular elbow is shown by line 1106.

[0125] Figures 42B to 42E show how the orientation of the end effector 1062 of the aforementioned exemplary arm mechanism, having the wrist pulley outline defined according to Figure 42A, is constrained as a function of the relative angle of the second link 1060 with respect to the first link 1058 (i.e., the relative angle between the first link and the second link).

[0126] Figure 43 shows the external shape of a pulley that may be used with the same arm geometry as the pulley external shape example described above and would produce the same or similar motion. Here, the orientation of the end effector 1120 is indicated by a black arrow, and the external shapes of the elbow pulley 1124 and the wrist pulley 1122 are shown as non-circular.

[0127] A band, belt, or cable mechanism may be provided to restrict the orientation of the end effector using two non-circular pulleys. For example, this mechanism may be applied to both single-end effector configurations (Figures 42A to 42E, etc.) and two-end effector configurations (Figures 32 and 36, etc.), in which case substantially the same kinematics may apply to all of them. In this additional example, the elbow pulley connected to the upper arm is non-circular, and the wrist pulley connected to the end effector is also non-circular. This may be provided as an alternative to the pulley shape example for the special case where the elbow pulley is circular and the wrist pulley is non-circular. As an example, the shape of each pulley is shown in Figure 43. As with Figure 42A, only half of each non-circular pulley is shown. Here, each shape is generated for the same arm geometry (link length) as the example of the non-circular pulley described above.

[0128] Figure 44 shows an example of the stepwise motion of a robot arm mechanism as its end effector extends along a straight path to the exemplary station described above. To cause the end effector of the robot arm mechanism to perform the exemplary motion shown in Figure 44, the shaft of the robot drive unit may be driven as shown in Graph 1150 of Figure 45. Graph 1150 shows the T1 shaft position 1152 and the T2 shaft position 1154 over time.

[0129] Figure 46 shows another example of the stepwise motion of the robot arm mechanism as the end effector extends to the same exemplary station along a path formed by two segments 1200, 1202 that merge around a common waypoint 1204. To achieve the exemplary motion in Figure 46, the shaft of the robot drive unit may be rotated as shown in graph 1250 of Figure 47. Graph 1250 shows the T1 shaft position 1252 and the T2 shaft position 1254 over time.

[0130] In Figures 45 and 47, the zero point of the angle of the robot drive shaft is defined as follows: When the arm mechanism is in the folded position (retracted position) and the third link (end effector) is aligned with the x-axis (i.e., pointing in the 3 o'clock direction), the angle of the T1 shaft is 0 degrees and the angle of the T2 shaft is 180 degrees. At this time, the angle of the first link is 0 degrees, the angle of the second link is 180 degrees, and the angle of the third link (end effector) is 0 degrees.

[0131] Figure 48 shows a side view of robot 1300, which includes an exemplary robot arm mechanism 1310 having two end effectors, attached to a robot drive unit 1312. This arm mechanism may consist of a first link 1314 (upper arm), a second link 1316 (forearm)A, a third link 1318 (end effector)A, a second link 1320 (forearm)B, and a third link 1322 (end effector)B.

[0132] An exemplary internal mechanism of the robot in Figure 48 is schematically shown in Figures 49A and 49B. This arm mechanism may be driven by a three-axis spindle comprising three coaxial shafts, for example, an outer T1 shaft 1340, a T2 shaft 1342, and an inner T3 shaft 1344. In some embodiments, the T2 shaft 1342 may be partially inside the outer T1 shaft 1340, and the inner T3 shaft 1344 may be partially inside the T2 shaft 1342. The orientation of the end effector A may be constrained by a band mechanism. This band mechanism may comprise an elbow pulley, a wrist pulley, and a band, belt, or cable. The elbow pulley may be connected to a first link, and the wrist pulley may be connected to a support structure comprising the end effector A, and the band, belt, or cable may transmit motion between these two pulleys. The band mechanism may feature a variable transmission ratio. The variable transmission ratio may be achieved, for example, using at least one pulley having a non-circular outer shape. For example, referring to Figure 49, the wrist pulley may feature a non-circular shape, and the elbow pulley may have a substantially circular shape. Similarly, the orientation of end effector B may be constrained by another band mechanism. This band mechanism may comprise an elbow pulley, a wrist pulley, and a band, belt, or cable. The elbow pulley may be connected to the first link, and the wrist pulley may be connected to end effector B, and the band, belt, or cable may transmit motion between these two pulleys. Here again, the band mechanism may feature a variable transmission ratio. The variable transmission ratio may be realized, for example, using at least one pulley having a non-circular shape. For example, referring to Figures 49A and 49B, the wrist pulley may feature a non-circular shape, and the elbow pulley may have a substantially circular shape. The variable transmission ratio may be chosen to change the orientation of each of the two end effectors in a predefined manner as a function of the relative position between the first link and the corresponding second link. For example, as shown in Figure 39, a variable transfer ratio may be selected so that the end effector follows a path to the station. An example is shown below.

[0133] The appropriate geometry of the arm mechanisms in Figures 48 and 49, i.e., the inter-joint link lengths and end effector lengths, may be determined based on the same guidelines described above for the exemplary 2-degree-of-freedom, 3-link robotic arm mechanism in Figure 40.

[0134] Similarly, consider the exemplary arm mechanism shown in Figures 40 and 41. In this arm mechanism, the orientation of the end effector may be constrained, for example, by a band mechanism comprising a circular elbow pulley and a non-circular wrist pulley. Assuming the location of the previously selected exemplary station and the geometry of the arm mechanism (X stn =388.6mm, Y stn (L1 = 1,030.2 mm, L1 = 287.9 ​​mm, L2A = L2B = L2 = 397.6 mm, and L3A = L3B = L3 = 565.5 mm), the same external shape previously described with respect to Figure 40 may be used for the two wrist pulleys.

[0135] Figure 50 shows an example of the stepwise motion of the robot arm mechanism as end effector A extends along a straight path 1440 to the exemplary station described above. In this particular example, end effector B and second link B remain folded over the first link so as to remain within the allowable swivel radius of the robot arm mechanism. To cause the robot arm mechanism to perform the exemplary motion in Figure 50, the shaft of the robot drive unit may be driven according to the exemplary motion profile shown in graph 1490 of Figure 51. Graph 1490 shows the T1 shaft position 1492, the T2 shaft position 1494, and the T3 shaft position 1496 over time.

[0136] Figure 52 shows another example of the stepwise motion of the robot arm mechanism as end effector A extends to the same exemplary station along a path formed by two segments 1540, 1542 that merge around a common waypoint 1544. In this example, the motion of the second link B, and therefore end effector B, is controlled to limit the range of motion of the payload being carried on end effector B. To achieve the exemplary motion in Figure 52, the shaft of the robot drive unit may be rotated as shown in graph 1640 of Figure 53. Graph 1640 shows the T1 shaft position 1642, the T2 shaft position 1644, and the T3 shaft position 1646 over time.

[0137] In Figures 51 and 53, the zero point of the angle of the robot drive shaft is defined as follows: When the arm mechanism is in the folded position (retracted position) and the third links (end effectors) A and B are aligned with the x-axis (i.e., pointing in the 3 o'clock direction), the angle of the T1 shaft is 0 degrees, and the angles of the T2 and T3 shafts are 180 degrees. At this time, the angle of the first link is 0 degrees, the angles of the second links A and B are 180 degrees, and the angles of the third links (end effectors) A and B are 0 degrees.

[0138] In one embodiment, the apparatus comprises a drive unit and a robotic arm. The drive unit comprises a first drive shaft rotatable around a first rotation axis and a second drive shaft rotatable around a second rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft. The robotic arm comprises an upper arm connected to the drive unit at the first drive shaft, a forearm coupled to the upper arm, and an end effector coupled to the forearm, wherein the forearm is coupled to the upper arm at a first rotary joint and is rotatable around the first rotary joint, the first rotary joint is driveable by a first band mechanism coupled to the second drive shaft, the end effector is coupled to the forearm at a second rotary joint and is rotatable around the second rotary joint, the second rotary joint is driveable by a second band mechanism coupled to the first rotary joint. The second band mechanism is configured to provide a variable transmission ratio.

[0139] In another embodiment, the first band mechanism comprises a shoulder pulley attached to the second drive shaft, a first elbow pulley coupled to the forearm, and a band, belt, or cable positioned between the shoulder pulley and the first elbow pulley to transmit motion between the shoulder pulley and the first elbow pulley.

[0140] In another embodiment, the second band mechanism comprises a second elbow pulley coupled to the upper arm, a wrist pulley coupled to the end effector, and a band, belt, or cable positioned between the second elbow pulley and the wrist pulley to transmit motion between the second elbow pulley and the wrist pulley.

[0141] In another embodiment, at least one of the second elbow pulley and the wrist pulley has a non-circular shape and provides the variable transmission ratio.

[0142] In another embodiment, the variable transfer ratio is selected to change the orientation of the end effector in a predefined manner as a function of the relative positions of the upper arm and the forearm.

[0143] In another embodiment, one or more of the first drive shaft and the second drive shaft are movable in the axial direction to facilitate the vertical movement of the robot arm.

[0144] In another embodiment, the apparatus comprises a drive unit and a robotic arm. The drive unit comprises a first drive shaft rotatable about a first rotation axis, a second drive shaft rotatable about a second rotation axis, and a third drive shaft rotatable about a third rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft, and the third drive shaft is coaxial with the second drive shaft, partially located inside the second drive shaft, and axially rotatable within the second drive shaft. The robot arm comprises an upper arm connected to the drive device at the first drive axis, a forearm coupled to the upper arm, and a first end effector and a second end effector coupled to the forearm, wherein the forearm is coupled to the upper arm at a first rotary joint and is rotatable around the first rotary joint, the first rotary joint is driveable by a single-stage band mechanism, the single-stage band mechanism comprises a first shoulder pulley driveable by the third drive axis, a first elbow pulley partially forming the first rotary joint, and a band, belt, or cable configured to transmit motion between the first shoulder pulley and the first elbow pulley, the first end effector and the second end effector are coupled to the forearm at a second rotary joint, and the orientation of the first end effector and the second end effector is controlled via a two-stage band mechanism. The first stage of the two-stage band mechanism comprises a second shoulder pulley driveable by the second drive shaft, a second elbow pulley partially forming the first rotational joint, and an upper band, belt, or cable configured to transmit motion between the second shoulder pulley and the second elbow pulley.The second stage of the two-stage band mechanism comprises a third elbow pulley coupled to the second elbow pulley, a first wrist pulley coupled to the first end effector, and a first lower band, belt, or cable configured to transmit motion between the third elbow pulley and the first wrist pulley. The second stage of the two-stage band mechanism further comprises a fourth elbow pulley coupled to the second elbow pulley, a second wrist pulley coupled to the second end effector, and a second lower band, belt, or cable configured to transmit motion between the fourth elbow pulley and the second wrist pulley. At least one of the motions between the first shoulder pulley and the first elbow pulley, the motion between the second shoulder pulley and the second elbow pulley, the motion between the third elbow pulley and the first wrist pulley, and the motion between the fourth elbow pulley and the second wrist pulley is performed with a variable transmission ratio.

[0145] In another embodiment, at least one of the third elbow pulley and the first wrist pulley has a non-circular shape and provides the variable transmission ratio to the two-stage band mechanism.

[0146] In another embodiment, at least one of the fourth elbow pulley and the second wrist pulley has a non-circular shape and provides the variable transmission ratio to the two-stage band mechanism.

[0147] In another embodiment, at least one of the first lower band, belt, or cable and the second lower band, belt, or cable are configured to cross each other.

[0148] In another embodiment, the variable transfer ratio is selected to change the orientation of the first and second end effectors in a predefined manner as a function of the relative positions of the upper arm, the forearm, and the second drive shaft.

[0149] In another embodiment, the first rotational joint is located either to the right of the imaginary line extending from the first shoulder pulley to the first wrist pulley, or to the left of the imaginary line extending from the first shoulder pulley to the first wrist pulley.

[0150] In another embodiment, the apparatus comprises a drive unit, a first robotic arm, and a second robotic arm. The drive unit comprises a first drive shaft rotatable about a first rotation axis, a second drive shaft rotatable about a second rotation axis, and a third drive shaft rotatable about a third rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located inside the first drive shaft, and axially rotatable within the first drive shaft, and the third drive shaft is coaxial with the second drive shaft, partially located inside the second drive shaft, and axially rotatable within the second drive shaft. The first robot arm comprises a first upper arm connected to the drive device at a first drive axis, a first forearm coupled to the first upper arm, and a first end effector coupled to the first forearm, wherein the first forearm is coupled to the first upper arm at a first rotary joint, the first rotary joint is driveable by the second drive axis using a first band mechanism, and the first end effector is coupled to the first forearm at a third rotary joint, the third rotary joint is driveable by the first rotary joint using a third band mechanism. The second robot arm comprises a second upper arm connected to the drive device at the third drive axis, a second forearm coupled to the second upper arm, and a second end effector coupled to the second forearm, wherein the second forearm is coupled to the second upper arm at a second rotary joint, the second rotary joint is driveable by the second drive axis using a second band mechanism, and the second end effector is coupled to the second forearm at a fourth rotary joint, the fourth rotary joint is driveable by the second rotary joint using a fourth band mechanism. At least one of the first band mechanism, the second band mechanism, the third band mechanism, and the fourth band mechanism has a variable transmission ratio.

[0151] In another embodiment, the first band mechanism comprises a first shoulder pulley attached to the first drive shaft, a first elbow pulley attached to the first forearm, and a first band, belt, or cable configured to transmit motion between the first shoulder pulley and the first elbow pulley.

[0152] In another embodiment, at least one of the first shoulder pulley and the first elbow pulley has a non-circular shape and provides the first band mechanism with the variable transmission ratio.

[0153] In another embodiment, the third band mechanism comprises a second elbow pulley operable with the first elbow pulley, a first wrist pulley coupled to the first end effector, and a third band, belt, or cable configured to transmit motion between the second elbow pulley and the first wrist pulley.

[0154] In another embodiment, at least one of the second elbow pulley and the first wrist pulley has a non-circular shape and provides the third band mechanism with the variable transmission ratio.

[0155] In another embodiment, the second band mechanism comprises a second shoulder pulley attached to the third drive shaft, a third elbow pulley attached to the second forearm, and a second band, belt, or cable configured to transmit motion between the second shoulder pulley and the third elbow pulley.

[0156] In another embodiment, at least one of the second shoulder pulley and the third elbow pulley has a non-circular shape and provides the second band mechanism with the variable transmission ratio.

[0157] In another embodiment, the fourth band mechanism comprises a fourth elbow pulley operable with the third elbow pulley, a second wrist pulley coupled to the second end effector, and a fourth band, belt, or cable configured to transmit motion between the fourth elbow pulley and the second wrist pulley.

[0158] In another embodiment, at least one of the fourth elbow pulley and the second wrist pulley has a non-circular shape and provides the variable transmission ratio to the fourth band mechanism.

[0159] In another embodiment, the variable transfer ratio is selected to change the orientation of the first end effector in a predefined manner as a function of the relative positions of the first upper arm and the first forearm.

[0160] In another embodiment, the transmission ratio of the first band mechanism and the transmission ratio of the third band mechanism are selected such that, when the first upper arm is driven by the first drive shaft and the second drive shaft is stationary, the center point of the first end effector follows a predefined path while maintaining a predefined orientation of the first end effector.

[0161] In another embodiment, the variable transfer ratio is selected to change the orientation of the second end effector in a predefined manner as a function of the relative positions of the second upper arm and the second forearm.

[0162] In another embodiment, the transmission ratio of the second band mechanism and the transmission ratio of the fourth band mechanism are selected such that, when the second upper arm is driven by the third drive shaft and the second drive shaft is stationary, the center point of the second end effector follows a predefined path while maintaining a predefined orientation of the second end effector.

[0163] It should be noted that the above explanation is merely an example. Various modifications and alterations can be conceived by those skilled in the art. For example, the features described in the various dependent claims within the claims can be combined with each other in any suitable combination. In addition, it is possible to selectively combine features from the various embodiments described above to create new embodiments. Therefore, this specification encompasses all changes, alterations, and variations included in the appended claims.

Claims

1. A device comprising a drive unit and a robotic arm, The drive unit comprises a first drive shaft rotatable about a first rotation axis, a second drive shaft rotatable about a second rotation axis, and a third drive shaft rotatable about a third rotation axis, wherein the second drive shaft is coaxial with the first drive shaft, partially located within the first drive shaft, and axially rotatable within the first drive shaft, and the third drive shaft is coaxial with the second drive shaft, partially located within the second drive shaft, and axially rotatable within the second drive shaft. The robot arm has an upper arm connected to the drive unit at the first rotation axis, a forearm connected to the upper arm at the first rotation joint and rotatable about the first rotation joint, and an end effector connected to the forearm at the second rotation joint. The first rotational joint is controlled by the second drive shaft using a first band mechanism, the first band mechanism comprising a shoulder pulley attached to the second drive shaft, a first elbow pulley attached to the forearm, and a first belt, band, or cable, the first belt, band, or cable configured to transmit motion between the shoulder pulley and the first elbow pulley. The orientation of the end effector is constrained by a second band mechanism, the second band mechanism comprising a second elbow pulley attached to the upper arm, a wrist pulley attached to the end effector, and a second belt, band, or cable, the second belt, band, or cable configured to transmit motion between the second elbow pulley and the wrist pulley. At least one of the motion transmitted between the shoulder pulley and the first elbow pulley, and the motion transmitted between the second elbow pulley and the wrist pulley, has a variable transmission ratio. In the apparatus, The variable transfer ratio is selected such that the orientation of the end effector changes as defined in advance as a function of the relative positions of the upper arm and the forearm. The relative positions of the upper arm and the forearm are expressed by the angle between the upper arm and the forearm. When the upper arm is driven by the first drive shaft and the second drive shaft is stationary, the variable transmission ratio is selected such that the end effector faces a predetermined direction and the reference point at the nominal center of the end effector follows a predetermined path. Device.

2. The apparatus according to claim 1, wherein one of the shoulder pulley and the first elbow pulley has a non-circular outer shape to provide the variable transmission ratio.

3. The apparatus according to claim 1, wherein one of the second elbow pulley and the wrist pulley has a non-circular shape to provide the variable transmission ratio.

4. The apparatus according to claim 1, wherein the predetermined route is selected to be an access route to a process module station of a semiconductor wafer processing tool.

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