Robot arm having a vacuum-compatible seal and an internal cooling flow path

Abstract

The present disclosure describes a robotic arm assembly for use in a vacuum environment. Such a robotic arm assembly may be characterized by one or more rotating joints having magnetic fluid seals or other vacuum-compatible seals. A coolant flow path segment may be provided through one or more of the one or more rotating joints to circulate coolant through one or more cooling features installed within the robotic arm assembly, thereby enabling active cooling of components within the robotic arm assembly, such as motors, magnetic fluid seals, sensors, and the like.

Description

Technical Field

[0001] Cross - reference to related applications: The PCT application form is submitted simultaneously with this specification as part of this application. Each application identified in the simultaneously submitted PCT application form and for which this application claims benefit or priority shall be incorporated herein by reference in its entirety for all purposes.

Background Art

[0002] Semiconductor processing tools typically feature multiple semiconductor processing chambers arranged around a Vacuum Transfer Module (VTM). Such a VTM often has one or more wafer handling robots, and each wafer handling robot has one or more robot arm assemblies. Using these robot arm assemblies, one or more corresponding end effectors are moved between different positions inside the VTM or adjacent to the VTM to transfer, for example, wafers from one position to another. For example, such a wafer handling robot may be configured to move wafers from one processing chamber connected to the VTM to another processing chamber connected to the VTM, or potentially from a load lock or processing chamber connected to the VTM to a buffer station installed inside the VTM.

[0003] The interior of the VTM, as its name implies, is usually maintained under vacuum conditions, i.e., at a pressure below atmospheric pressure, which is to match or at least approximate the pressure typically maintained in the processing chambers attached to it, thereby reducing the pressure difference between the processing chamber and the VTM. This pressure difference must be restored, for example, by opening a valve or door that fluidically isolates them after one of the processing chamber and the VTM is fluidically connected.

[0004] This specification describes various improvements to robots that can be used in a vacuum environment.

Summary of the Invention

[0005] Details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will be apparent from this specification, the drawings, and the claims.

[0006] In some embodiments, an apparatus comprises a robot arm base, a robot arm assembly including one or more arm links and a first set of one or more rotational joints, each of the first set of one or more rotational joints including a corresponding vacuum-compatible seal, a component defining a plurality of coolant flow path segments, and a first set of one or more cooling features, each of the first set of one or more cooling features being fluidly connected to and fluidly disposed between at least two of the coolant flow path segments. The base rotational joint of the one or more rotational joints may rotatably connect a first arm link of the one or more arm links to the robot arm base, and at least two of the coolant flow path segments may extend from the robot arm base, through the base rotational joint, and into at least the first arm link.

[0007] In some embodiments, the one or more vacuum - compatible seals may include at least a first vacuum - compatible seal, the one or more cooling features may include one or more vacuum - compatible seal cooling features, the one or more vacuum - compatible seal cooling features may include a first vacuum - compatible seal cooling feature, and the first vacuum - compatible seal cooling feature is configured to cool the first vacuum - compatible seal when coolant flows into the first vacuum - compatible seal cooling feature via at least one of the coolant flow path segments and out of the first vacuum - compatible seal cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

[0008] In some such embodiments, the first vacuum - compatible seal cooling feature may include a passage that extends through at least a portion of a tubular zone having a centerline coaxial with a rotational axis of one of the one or more rotary joints including the first vacuum - compatible seal, and the tubular zone may be surrounded by one or more faces of the first vacuum - compatible seal that face radially inwardly toward a rotational axis of one of the one or more rotary joints including the first vacuum - compatible seal.

[0009] In some embodiments, the passage may be at least partially bounded by one or more faces of the first vacuum - compatible seal that face radially outwardly from a rotational axis of one of the one or more rotary joints including the first vacuum - compatible seal.

[0010] In some embodiments, the first vacuum - compatible seal cooling feature may include a passage that extends through at least a portion of a tubular zone having a centerline coaxial with a rotational axis of one of the one or more rotary joints including the first vacuum - compatible seal, and the tubular zone may be surrounded by one or more faces of the first vacuum - compatible seal that face radially inwardly toward a rotational axis of one of the one or more rotary joints including the first vacuum - compatible seal.

[0011] In some embodiments, the passageway may be at least partially bounded by one or more surfaces of a first vacuum-compatible seal that face radially inwardly toward the axis of rotation of one of the one or more rotary joints that include the first vacuum-compatible seal.

[0012] In some embodiments, the passageway may have an annular shape or an annular sector shape.

[0013] In some embodiments, the robotic arm assembly may include a first motor, the one or more cooling features may include one or more motor cooling features, the one or more motor cooling features may include a first motor cooling feature, the first motor cooling feature is disposed adjacent to or surrounding a portion of the first motor, and the first motor cooling feature is configured to cool the first motor when coolant flows into the first motor cooling feature via at least one of the coolant flow path segments and out of the first motor cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

[0014] In some embodiments, the one or more cooling features may include one or more arm link cooling features, the one or more arm link cooling features may include a first arm link cooling feature, the first arm link cooling feature is disposed adjacent to or within the material forming one of the one or more arm links, and the first arm link cooling feature is configured to cool the first arm link when coolant flows into the first arm link cooling feature via at least one of the coolant flow path segments and out of the first arm link cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

[0015] In some embodiments, the first arm link cooling feature may extend along at least half of the length portion of the arm link made of a material in which the first arm link cooling feature is adjacent to or disposed within.

[0016] In some embodiments, the apparatus may further include a first sensor installed inside one of the one or more arm links, the one or more cooling features may include one or more sensor cooling features, the one or more sensor cooling features may include a first sensor cooling feature, the first sensor cooling feature is disposed adjacent to or surrounding a part of the first sensor, and the first sensor cooling feature is configured to cool the first sensor when a coolant flows into the first sensor cooling feature via at least one of the coolant flow path segments and flows out of the first sensor cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

[0017] In some embodiments, the first sensor may be an optical sensor.

[0018] In some embodiments, the first sensor may be an image sensor.

[0019] In some embodiments, the one or more arm links may include a first end effector arm link having a first end effector, and the first sensor may be in the first end effector arm link.

[0020] In some embodiments, the first sensor may be oriented to collect data from a position below the first end effector arm link.

[0021] In some embodiments, the first sensor may be oriented to collect data from a position above the first end effector arm link.

[0022] In some embodiments, the first end effector arm link may also be the first arm link.

[0023] In some embodiments, the apparatus may further include a second sensor, one or more arm links may further include a second end effector arm link having a second end effector, the second sensor may be disposed inside the second end effector arm link, one or more arm links may further include a forearm link, the first end effector arm link may be rotatably connected to the forearm link by a first rotational joint of one or more rotational joints, the second end effector arm link may be rotatably connected to the forearm link by a second rotational joint of one or more rotational joints, one or more sensor cooling features may include a second sensor cooling feature, the second sensor cooling feature is disposed adjacent to or surrounding a portion of the second sensor, and the second sensor cooling feature is configured to cool the second sensor when coolant flows into the second sensor cooling feature via at least one of the coolant flow path segments and then flows out of the second sensor cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

[0024] In some embodiments, the first rotational joint may be configured such that the first end effector arm link is rotatable about a first axis of rotation relative to the forearm link, the second rotational joint may be configured such that the second end effector arm link is also rotatable about the first axis of rotation relative to the forearm link, the first end effector may be disposed at a higher altitude than the second end effector, the first end effector link may include a first body portion and a first shaft portion, the first shaft portion may extend through the second end effector link, the first shaft portion may be supported by the first rotational joint, the first rotational joint may include a first vacuum-compatible seal that seals between the second end effector link and a first portion of the first end effector link, both the second sensor and the second sensor cooling feature may be installed inside the second arm link at a position radially external to the first vacuum-compatible seal relative to the first axis of rotation, and the first vacuum-compatible seal may be disposed between the first body portion and a position on the first shaft portion where a coolant flow path segment leading to the second sensor cooling feature exits from the first portion.

[0025] In some embodiments, the opening may extend through the first shaft portion over a sector of an arc centered about the first axis of rotation. A coolant flow path segment leading to the second sensor cooling feature may exit from the first shaft portion via the opening.

[0026] In some such embodiments, the sector of the arc may extend at least 90°.

[0027] In some embodiments, one or more arm links may include a plurality of arm links.

[0028] In some embodiments, the second rotational joint may rotatably connect two of the plurality of arm links, at least two of the coolant flow path segments may pass through the base rotational joint, and at least two of the coolant flow path segments may pass through the second rotational joint.

[0029] In some embodiments, at least some of the coolant flow path segments may be at least partially provided by flexible polymer tubing.

[0030] In some embodiments, the components defining each of the flow path segments may include one or more components selected from a length portion of flexible polymer tubing, a length portion of rigid tubing, a flow diverter, a through connector, and a fitting.

[0031] In some embodiments, the apparatus may further include a purge gas bleed feature. The purge gas bleed feature may include one or more purge gas outlets fluidly connected to one or more purge gas plenums and configured to direct purge gas from the one or more purge gas plenums radially outward proximate to a corresponding one of the one or more rotary joints. Further, one or more purge gas lines may be routed from a robot arm base, through a base rotary joint, and into at least a first arm link.

[0032] In some embodiments, at least one of the one or more rotary joints may include a corresponding vacuum-compatible seal that is a magnetic fluid seal.

[0033] In some embodiments, each of the rotary joints may include a corresponding vacuum-compatible seal that is a magnetic fluid seal.

Brief Description of the Drawings

[0034] In the following description, the following figures are referenced. Each figure is not intended to be limiting and is provided merely to facilitate discussion below.

[0035]

Figure 1

[0036]

Figure 1A

[0037]

Figure 1B

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Figure 1B-

[0039]

Figure 1C

[0040]

Figure 1C-

[0041]

Figure 2

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Figure 3

[0043]

Figure 4A

Figure 4B

Figure 4C

[0044]

Figure 5

[0045] The above figures are provided to facilitate understanding of the concepts discussed in this disclosure, and are intended to illustrate some embodiments that are within the scope of this disclosure but are not intended to be limiting. Embodiments that are consistent with but not shown in this disclosure are also considered to be within the scope of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0046] As previously described, semiconductor processing tools often include a vacuum transfer module (VTM), which may include one or more wafer handling robots having a robot arm assembly installed inside the VTM. Such a robot arm assembly typically includes at least one rotational joint that connects the robot arm assembly to a robot arm base that is fixed relative to the VTM (e.g., attached to the bottom surface of the VTM). The robot arm base may include, for example, one or more motors that may be actuated to rotate and / or lift the robot arm assembly relative to the base. At a minimum, the wafer handling robot will have at least one rotational joint that allows the robot arm assembly to rotate relative to the robot arm base.

[0047] In many instances, the robotic arm assembly included in the VTM may have a plurality of arm links, e.g., rigid links connected end-to-end by corresponding rotational joints, each link having the ability to rotate with respect to other link(s) or link(s) to which it is connected. For example, a robotic arm assembly having three links may rotate the outermost arm link about the robotic arm base, move it to any of a variety of positions around the robotic arm base, and / or rotate it with respect to the other arm link(s), thereby providing a high degree of flexibility with respect to where such a robotic arm assembly can carry a wafer. Thus, while some embodiments of the concepts discussed herein may feature a robotic arm assembly having only one rotational joint and one arm link, it will be understood that other embodiments of the concepts discussed herein may feature a robotic arm assembly having a plurality of rotational joints and a plurality of arm links.

[0048] Disclosed herein is a new type of robotic arm for use in a vacuum environment such as a VTM. By providing each rotating joint of the robotic arm assembly with a corresponding vacuum-compatible rotary seal (e.g., a magnetic fluid seal), the internal space of the robotic arm assembly is fluidly isolated from such a vacuum environment, while at the same time, the internal space within the robotic arm link(s) can be fluidly connected to, for example, the robotic arm base. Such fluid isolation allows the internal space within the robotic arm link(s) to be maintained at a higher pressure, e.g., atmospheric pressure, compared to the vacuum environment surrounding the robotic arm assembly. This can facilitate, for example, the cooling of various components that may be installed inside the robotic arm assembly, such as sensors, motors, bearings, etc. For example, sensors, motors, and bearings can all generate heat during use. For example, heat generated by the resistance of electrical components and / or heat generated by the friction or rolling resistance of mechanical components, etc. Such heat may be difficult to passively process, for example, through heat conduction through the robotic arm segment. By configuring a robotic arm assembly having sealed rotating joints such that the interior of the robotic arm assembly can be maintained at a higher pressure than the vacuum environment in which the robotic arm assembly is used, for example, a flexible polymer tubing that is routed through the internal space of the robotic arm assembly (e.g., through one or more of one or more rotating joints of the robotic arm assembly) can be used. Such tubing may be used to define a coolant flow path segment, which may be used to circulate a coolant through one or more cooling features, which may be adjacent to or installed within components within the robotic arm link(s) that may require cooling. By using such flexible tubing, routing of the flow path through the rotating joint(s) is possible without relying on complex rotating joints incorporating fluid transfer functions such as rotary unions.The use of flexible piping for fluid routing in a vacuum environment (at least in a vacuum environment with strict atmospheric purity requirements, such as inside a semiconductor processing system) is typically avoided. This is because most such piping causes gas outgassing problems and / or is made of materials that are not rigid enough to prevent piping expansion when exposed to a vacuum environment while under pressure. Teflon (registered trademark) may at first seem like one of the only suitable candidate materials for such applications, but using Teflon in such situations is typically precluded because there is a possibility of leakage (either through the material itself or at the location where the piping connects to the connection fittings).

[0049] Furthermore, by sealing the internal space of a robot arm assembly from the vacuum environment surrounding the robot arm assembly, components that might otherwise be problematic can be used inside the robot arm assembly. For example, polymeric piping for fluid conveyance, polymeric coating materials for cables or wiring, adhesives, ball bearings, lubricants, etc. may generate contaminants such as chemical species, dust, or particulates, and if these leak out into the vacuum environment, it can cause serious contamination problems. For example, particulates that can be generated inside a robot arm assembly due to frictional wear of bearings can be drawn into the vacuum environment and land on a wafer being transported through such an environment, thereby contaminating the wafer and potentially reducing the process yield. Similarly, gas species that can be emitted from polymeric components inside a robot arm assembly can leak out into the vacuum environment and react with materials placed on a wafer being transported through the vacuum environment, thereby affecting the uniformity of the wafer and reducing the wafer yield. In such a robot arm assembly, by providing a magnetic fluid seal, or other vacuum-rated rotational interface, the robot arm assembly may be sealed from the vacuum environment such that there is little chance for contaminants originating inside the robot arm assembly to migrate into the vacuum environment.

[0050] A robot arm assembly, such as those described herein, may be configured to actively cool components mounted on any of the arm links of a multi-link robot arm assembly, thereby enabling even the outermost arm link of such a robot arm assembly to readily accommodate components that generate heat or are heat-sensitive features. This may enable, for example, placement of equipment, such as motors, bearings, seals, and / or sensors, at locations within such a robot arm assembly that would otherwise typically be difficult to cool. Additionally, a wafer handling robot may often be required to, for example, retrieve or handle wafers at elevated temperatures, such as 200° C. or greater. Such wafers may radiate thermal energy that is absorbed by the end effector(s) of such a robot arm assembly, thereby imparting additional thermal energy to components within the portion of the robot arm assembly that is thermally proximal to the end effector.

[0051] FIG. 1 is a diagram of an exemplary wafer handling robot incorporating a rotary joint with a vacuum compatible seal and an active cooling system as described above. FIG. 1 includes three dashed rectangular boundaries labeled “A,” “B,” and “C” that respectively correspond to the boundaries of FIGS. 1A, 1B, and 1C. FIGS. 1A, 1B, and 1C may be understood to represent detailed views of the respective portions of the wafer handling robot of FIG. 1 enclosed within each rectangular boundary.

[0052] The wafer handling robot of FIG. 1 is provided as an exemplary robot showing a particular configuration of a robot arm assembly having, for example, a plurality of arm links and a plurality of end effectors. However, it will be understood that the concepts discussed with respect to the wafer handling robot of FIG. 1 can also be realized in a robot arm assembly having more or fewer arm links (including only a single arm link) and / or more or fewer end effectors. Further, the exemplary wafer handling robot of FIG. 1 includes three different types of components for which active cooling is provided. In other embodiments, it will be understood that only some of such components may be included, or that components other than those shown, which can be cooled in a similar manner, may be included.

[0053] Also, it will be understood that FIG. 1 shows multiple examples of several elements or features. In such cases, different examples of such elements or features can be referred to by the same callout number but with different lowercase suffixes (e.g., 100a, 100b, 100c, etc.). References to such elements may typically be made using only the numerical portion of such a callout (e.g., omitting the suffix letter), but it will be understood that there may not be a particular callout consisting of only that number. Further, in some cases, it will be understood that the suffixes used for examples of some elements or features may not be consecutive. For example, examples 100c and 100d may exist, but examples 100a or 100b may not exist.

[0054] FIG. 1 shows a cross-sectional view of a wafer handling robot 106. The wafer handling robot 106 may include a robot arm base 108 and a robot arm assembly 110 supported by the robot arm base 108. The robot arm assembly 110 may include one or more arm links 116, which in this example include a first arm link 116a, a second arm link 116b, a third arm link 116c, a fourth arm link 116d, and a fifth arm link 116e. The robot arm assembly 110 may also include a set of one or more rotational joints 112. In this example, the set of rotational joints of the robot arm assembly 110 includes a first rotational joint 112a, a second rotational joint 112b, a third rotational joint 112c, a fourth rotational joint 112d, and a fifth rotational joint 112e. Each rotational joint 112 of the set of rotational joints 112 may include one or more rotary bearings 136 and a magnetic fluid seal 124. Although the present disclosure uses a magnetic fluid seal as a vacuum-compatible seal in the following examples, other types of vacuum-compatible rotary seals may be used as well, and it will be understood that when referring to a "magnetic fluid seal cooling feature," it may also be replaced by referring to a "vacuum-compatible seal cooling feature." For example, a vacuum-compatible seal may be understood to provide a seal (e.g., a vacuum in the range of 40 mTorr to 550 mTorr or less) across a rotational interface sufficient to maintain a vacuum on one side of the seal while maintaining atmospheric pressure on the opposite side of the rotational interface. In some examples, a vacuum-compatible seal may include a sliding seal, which is the case, for example, when there is sliding contact between a compliant seal structure (such as an elastomeric seal) and a seal surface (such as a shaft). In other examples, a vacuum-compatible seal may include a non-sliding seal, which is the case, for example, when there is no sliding contact between two structures at the seal interface. In such a vacuum-compatible seal, for example, the seal element may be provided by a fluid material such as a magnetic fluid, thereby eliminating rubbing between individual parts at the seal interface and reducing the generation of fine particles.

[0055] The rotary bearing 136 is, for example, a ball bearing or other bearing that can enable one arm link 116 to rotate relative to another arm link or a robot arm base. In this example, each of the rotary bearings 136 includes an inner race 138a, an outer race 138b, and a plurality of ball bearings 140 disposed therebetween, as shown in the exemplary rotary bearing of FIG. 3.

[0056] The magnetic fluid seal 124 is a type of seal that can be used to provide a vacuum - compatible seal across a rotational interface between two components configured to rotate relative to each other. A typical magnetic fluid seal may include two generally annular pole pieces 127a and 127b having coaxial centerlines and spaced apart from each other along the centerlines, as shown in FIG. 2. The pole pieces 127 may be made of a steel material such as iron, for example. By placing a circular array of magnets 126 between the two pole pieces 127, the polarities of the magnets 126 may be oriented in the same direction. For example, the N - side of each magnet may be magnetically clamped to the pole piece 127a and the S - side of each magnet may be magnetically clamped to the pole piece 127b. In some examples, a single annular magnet 126 may be used instead of the circular array of magnets 126.

[0057] The core 128 may be arranged to pass through the pole piece 127. The core 128 may have, for example, a center line coaxial with the center line of the pole piece 127. The core 128 may be supported with respect to the pole piece 127 by one or more rotary bearings, whereby the core 128 is concentric with the inner surface(s) of the pole piece 127, and there may be a small radial gap between the outermost surface of the core 128 and the surface of the pole piece 127 facing radially inward in the region axially overlapping the pole piece 127. The core 128 may include a plurality of circumferential grooves or indentations along the portion of its length axially overlapping the pole piece 127, thereby bringing a plurality of circumferential ridges or waveforms closer to the pole piece 127. A somewhat doughnut-shaped magnetic flux region may be generated by the magnetic field provided by the magnet 126, and the magnetic flux band travels from the magnet(s) 126 into the pole piece 127a, then jumps across the gap between the core 128 and the pole piece 127a. The magnetic flux band then travels along the core 128, jumps across the gap, returns into the pole piece 127b, and returns to the magnet(s) 126.

[0058] The magnetic flux intensity within the gap is naturally stronger at the positions where each "peak" in the circumferential direction exists compared to the circumferential "valleys" between the circumferential "peaks". When the magnetic fluid 130 is introduced into the gap between the pole piece 127 and the core 128, the magnetic fluid naturally aggregates in the radial gap between the circumferential peak and the pole piece 127 due to the higher magnetic flux in that region. Thereby, for example, a continuous magnetic fluid barrier crossing the gap is formed from the pole piece 127 to the core 128. Such barriers can each act as a seal, whereby, in effect, a continuous circumferential seal is provided by the magnetic fluid 130. When exposed to a vacuum environment, the magnetic fluid seal may form a leakage prevention (or sufficient leakage prevention) interface as a whole between the core 128 and the pole piece 127, whereby the core 128 and the pole piece 127 can rotate relative to each other while preventing gas from leaking therebetween. Further, since the magnetic fluid 130 has magnetism, the particulate debris that may be generated from the magnetic fluid 130 tends to remain trapped between the pole piece 127 and the core 128, thereby reducing or eliminating the possibility of particulate contamination from the rotary joint 112 inside the VTM.

[0059] In some magnetic fluid seals, the core 128 and the pole piece 127 may be positioned in reverse, such that the core 128 surrounds the pole piece 127 instead of the pole piece 127 surrounding the core 128.

[0060] Furthermore, in some magnetic fluid seals, the magnetic fluid seal may include one or more cooling cavities, and a coolant may flow through the cooling cavities to cool the magnetic fluid seal. For example, the core 128 may have an annular channel on the innermost surface of the core 128 (the outermost surface when the core surrounds the pole piece 127). Thus, when the shaft is inserted into the central hole of the core 128, an annular cavity 134 that bounds the shaft may be defined by the annular channel and the outer surface of the shaft. O-rings 1A32a and 132b (or other suitable seals) may be used to seal the core 128 against the shaft and prevent axial leakage of the coolant from the cavity 134. The inlet and outlet may be fluidly connected to the cavity 134, for example, by being disposed diametrically opposite each other to allow the coolant to flow into, pass through, and then out of the cavity 134.

[0061] Return to the wafer handling robot 106, and one of the one or more rotary joints 112 may function as a base rotary joint that rotatably connects one of the arm links 116 to the robot arm base 108. In this example, the first rotary joint 112a functions as the base rotary joint. In an embodiment having a plurality of arm links 116, each arm link 116 may be rotatably connected to another one of the arm links 116 by a corresponding rotary joint 112. For example, in the illustrated exemplary robot arm assembly 110, the first arm link 116a is rotatably connected to the second arm link 116b by the second rotary joint 112b, and the second arm link 116b is rotatably connected to the third arm link 116c by the third rotary joint 112c. The fourth arm link 116d and the fifth arm link 116e are each rotatably connected to the third arm link 116c by the fourth rotary joint 112d and the fifth rotary joint 112e, respectively. In this example, since the fourth rotary joint 112d and the fifth rotary joint 112e are coaxial with each other, both the fourth arm link 116d and the fifth arm link 116e are rotatable with respect to the third arm link 116c about a common rotation axis.

[0062] One or more of the arm links 116 of the robot arm assembly 110 may function as end effector links, which terminate at an end effector 176 that can be used, for example, to support a semiconductor wafer (or other article) carried by the robot arm assembly 110. In this exemplary robot arm assembly 110, there are two end effector arm links, with the fourth arm link 116d (which supports the first end effector 176a) functioning as the first end effector arm link and the fifth arm link 116e (which supports the second end effector 176b) functioning as the second end effector link. In some examples, the end effector link(s) may be connected to another arm link that directly supports the end effector link(s) relative to the rest of the robot arm assembly. The arm link that directly supports the end effector link(s) may be referred to as the "forearm link". The robot arm assembly may in some examples feature a single arm link, in which case it will be understood that the end effector arm link may simply be directly connected to the robot arm base 108.

[0063] The various arm links 116 shown are each independently drivable using the corresponding motor 162, but in some multi-link robot arm assemblies, two or more of the arm links may be kinematically coupled so as to move together in a kinematically interlocked manner. Thereby, both arm links can be moved relative to each arm link that supports both arm links in response to a single motion input, for example, a rotational input from a single motor.

[0064] For example, as can be more clearly seen from FIG. 1A, the first arm link 116a includes a first motor 162a having a first stator 164a and a first rotor 166a. The first rotor 166a may project upward from the robot arm base 108 and be connected to a shaft that is spatially fixed relative to the robot arm base 108. By connecting the first stator 164a to the first arm link 116a, the first rotor 166 and the first stator 164a may be rotated relative to each other when power is supplied to the first motor 162a, thereby causing the first arm link 116a to rotate relative to the robot arm base 108. Of course, the illustrated configuration may be reversed. For example, the first motor 162a may be installed on the robot arm base 108, and the shaft may instead extend downward from the first arm link 116a and enter the robot arm base 108 and the first motor 162a.

[0065] As shown in FIG. 1A, the first arm link 116a may also include a second motor 162b having a second stator 164b and a second rotor 166b. The second stator 164b may be spatially fixed relative to the first arm link 116a, and the second rotor 166b may be spatially fixed relative to the second arm link 116b. For example, the second arm link 116b may have a shaft that extends downward and enters the second arm link 116b and the second rotor 166b. When the second motor 162b is actuated to cause relative rotation between the second stator 164b and the second rotor 166b, the resulting rotational output may cause the second arm link 116b to rotate relative to the first arm link 116a.

[0066] As can be seen from the figure, the first rotary joint 112a may include a pair of rotary bearings 136a and 136a' that can rotatably support the first arm link 116a with respect to the robot arm base 108. The first rotary joint 112a may also include a magnetic fluid seal 124a that can seal between the first arm link 116a and a shaft protruding from the robot arm base 108. Note that the rotary bearings 136a and 136a' are sealed within the first arm link 116a by the magnetic fluid seal 124a.

[0067] As can be more clearly seen from FIG. 1A, two coolant flow path segments 120a and 120b are routed from the robot arm base 108, through the first rotary joint 112a, and into the first arm link 116a. For example, a shaft extending upward from the robot arm base 108 into the first arm link 116a may have a bore or passage through which the coolant flow path segments 120a and 120b may be routed. A gap may exist between the inner surface of the first arm link 116a facing the end of the shaft of the robot arm base 108 so that the coolant flow path segment 120 can be routed to components or positions that are radially external to the first rotary joint 112a. One or more of the coolant flow path segments 120a may be fluidly connected to a coolant source 194, and one or more of the coolant flow path segments 120b may be fluidly connected to a coolant return section 196. Alternatively, the coolant flow path segments 120a and 120b may be fluidly connected, for example, to an external heat exchanger or coolant reservoir and a pump that circulates the coolant from the heat exchanger or reservoir through the coolant flow path segments and back to the heat exchanger or reservoir. Examples of coolants that may be used include water, water mixed with antifreeze, galden, or other suitable fluids.

[0068] In a similar manner, one or more cables 118 may also be routed through the first rotational joint 112a. The one or more cables 118 may be electrical cables configured to transmit electrical signals (e.g., power signals and / or data signals) to components within the robotic arm assembly 110. The one or more cables 118 may be connected to a controller 198 that may provide such power signals and / or data signals to control the wafer handling robot.

[0069] The coolant flow path segment 120 may generally be configured to route coolant fluid to one or more cooling features that may be disposed within the robotic arm assembly. For example, the magnetic fluid seal 124a may have a first magnetic fluid seal cooling feature 144a, which may be disposed adjacent to or surround the magnetic fluid seal 124a. In this example, the first magnetic fluid seal cooling feature 144a includes an annular cavity that extends around and is partially defined by the outer periphery of the magnetic fluid seal 124a. The first magnetic fluid seal cooling feature 144a may have, for example, an inlet feature that may receive coolant sent to the first magnetic fluid seal cooling feature 144a by one of the coolant flow path segments 120a, and an outlet feature that sends coolant from the first magnetic fluid seal cooling feature 144a to one of the coolant flow path segments 120b. The coolant flow path segments 120a and 120b may thus be used to flow coolant through the first magnetic fluid seal cooling feature 144a, thereby cooling the magnetic fluid seal 124a.

[0070] As shown in the figure, the first magnetic fluid seal cooling feature 144a is an annular void surrounding the magnetic fluid seal 124a. In this case, the annular void is defined by an annular channel on the outer surface of the core of the magnetic fluid seal 124a and another annular channel on the inner surface of the bore of the first arm link 116a that receives the magnetic fluid seal 124a. However, in other embodiments, such a channel may be characterized by being in one or the other of such positions. Further, other arrangements of magnetic fluid seal cooling features may be used. For example, a C-shaped cooling feature in which an inlet and an outlet are arranged at both ends of a C-shaped passage that surrounds or almost surrounds the magnetic fluid seal. Generally speaking, the magnetic fluid seal cooling feature may include at least one or more passages at least partially disposed within a tubular zone having a central axis coaxial with the rotation axis of the rotary joint featuring the magnetic fluid seal, such as a C-shaped or annular sector-shaped passage, two C-shaped passages forming an annular passage, etc. Such a tubular zone may, in some cases, surround one or more surfaces of the cooled magnetic fluid seal that face radially inward toward its rotation axis. In other examples, the tubular zone may instead be surrounded by one or more surfaces of the cooled magnetic fluid seal that face radially inward toward its rotation axis. In other embodiments, such a passage or passages may simply be arranged adjacent to the cooled magnetic fluid seal. In some embodiments, at least a portion of such a passage or passages may be defined by a surface of the cooled magnetic fluid seal, for example, a surface that faces radially outward or radially inward depending on the arrangement of the magnetic fluid seal cooling feature with respect to the cooled magnetic fluid seal.

[0071] Similar to the first rotary joint 112a, the second rotary joint 112b has a pair of rotary bearings 136b and 136b' that can rotatably support the second arm link 116b with respect to the first arm link 116a. The second rotary joint 112b may also include a second magnetic fluid seal 124b that can seal between the first arm link 116a and a shaft protruding from the second arm link 116b. The second magnetic fluid cooling feature 144b that is fluidly connected and placed between two of the coolant flow path segments 120 is arranged to provide cooling to the second magnetic fluid seal 124b.

[0072] Corresponding magnetic fluid cooling features are also provided for the other rotary joints 112c, 112d, and 112e in this example, so that it will be understood that each magnetic fluid seal of the rotary joint 112 can be actively cooled by its own dedicated magnetic fluid seal cooling feature 144. In some embodiments, magnetic fluid seals 124 (such as magnetic fluid seals 124d and 124e, etc.) arranged close to each other may share a common magnetic fluid seal cooling feature. For example, such magnetic fluid seals may be arranged close enough that heat from one magnetic fluid seal can flow through the other magnetic fluid seal and reach the magnetic fluid seal cooling feature surrounding both of them.

[0073] Generally speaking, the cooling features discussed in this specification, such as the magnetic fluid seal cooling feature 144, may each be fluidly connected to and placed between at least two coolant flow path segments, whereby the coolant is sent to the cooling feature via one of those coolant flow path segments and then discharged from the cooling feature by the other one or more of those coolant flow path segments. Each coolant flow path segment 120 may be defined by, for example, one or more components. For example, it may be a length portion of a flexible pipe (such as a polymer pipe), a length portion of a rigid pipe, a connecting fitting, a through connector (or a part thereof), and a flow splitting device (or a part thereof), etc.

[0074] As can be seen from this example, there are a plurality of coolant flow path segments 120a and 120b, and the coolant flow path segment 120a delivers coolant to various cooling features used, and the coolant flow path segment 120b recovers coolant from those same cooling features. In this example, each of the various coolant flow path segments 120a and 120b is fluidly connected to its respective joining block 122, and the joining block subdivides or splits the coolant flow between different coolant flow path segments 120a or merges or combines the coolant flow from different coolant flow path segments 120b. Such a joining block 122 is arranged within the robot arm assembly 110 such that all the joining blocks 122 are connected in series by the corresponding coolant flow path segments 120a and 120b, and additional coolant flow path segments 120 extend from each joining block 122 to nearby cooling features so as to supply coolant to those cooling features in parallel.

[0075] As can be seen from the figure, another pair of coolant flow path segments 120 passes from the first arm link 116a through the second rotary joint 112b to the second arm link 116b. Such a coolant flow path segment 120 may, for example, pass upward through a hollow shaft that extends downward and enters the first arm link 116a from the second arm link 116b.

[0076] The second arm link 116b is shown in more detail in FIG. 1B. As can be seen from the figure, the second arm link 116b has a different motor configuration inside, and the third motor 162c (represented by a box, but typically including a rotor and a stator like the first motor 162a and the second motor 162b) is configured to provide a rotational input to the third arm link 116c via a pulley system. For example, the third motor 162c may have a rotational output connected to a pulley 168c, and this rotational output is then kinematically coupled to a pulley 168c' by a belt 170c. The belt 170c may be, for example, a steel belt. Steel belts do not emit gas and generate a minimal amount of particulate contamination, so they are typically used in robotic arm assemblies used in a vacuum. However, since the inside of the second arm link 116b is fluidically isolated from the vacuum environment around the robotic arm assembly 110 by a magnetic fluid seal 124, it is also possible to use other types of materials for the belt 170c, such as polymer belts, fiber-reinforced polymer belts, etc., which are usually avoided in robots designed for a vacuum environment. Note that in the illustrated exemplary robotic arm assembly 110, there is no pulley 168a or pulley 168b. The omission of the suffix a / b is intentional so that the pulleys 168c and 168c' can share the same suffix as the motor 162 with which they are associated.

[0077] When the third motor 162c is actuated, for example, in response to power and / or control signals received via a cable 118, the rotation of the pulley 168c drives the belt 170c to drive the pulley 168c', thereby rotating the third arm link 116c relative to the second arm link 116b.

[0078] As can be seen from the figure, the third rotational joint 112c includes a pair of rotary bearings 136c and 136c', like the rotational joint 112 discussed above, which support the third arm link 116c with respect to the second arm link 116b, for example, via a shaft protruding from the lower surface of the third arm link 116c. The third rotational joint 112c also includes a third magnetic fluid seal 124c that seals between the third arm link 116c, for example, between the shaft protruding from the lower surface of the third arm link 116c and the second arm link 116b, thereby sealing the interior of the second arm link 116b against potential leakage through the third rotational joint 112c.

[0079] Also shown is a third magnetic fluid seal cooling feature 144c configured to cool the third magnetic fluid seal 124c. The third magnetic fluid seal cooling feature 144c may be, for example, similar to the magnetic fluid seal cooling feature 144 discussed above and may be fluidly connected to coolant flow path segments 120a and 120b that lead to the second joint block 122b (the first joint block being joint block 122a), for example.

[0080] In addition to the third magnetic fluid seal cooling feature 144c, the second arm link 116b also includes another type of cooling feature, for example, a third motor cooling feature 146c (in this example, it does not feature a first or second motor cooling feature. The ordinal indication of "third" is used to make the motor cooling feature share the same ordinal indication as the motor it cools). The third motor cooling feature 146c may be disposed adjacent to or surrounding the third motor 162c, and may be, for example, a cooling jacket. The cooling jacket may be, for example, a housing, a part or all of the circumference of which may contact the motor, may have one or more internal cavities, and through which a coolant flowing from one of the coolant flow path segments 120 for removing heat from the third motor cooling feature 146c cools the third motor 162c. The cooling jacket may have a structure similar to that of the magnetic fluid seal cooling feature 144 discussed above, for example, an internal cavity or passage(s) of a similar structure. Also, it will be understood that the magnetic fluid seal cooling features 144 may be provided as separate components, for example, similar to the cooling jacket providing the third motor cooling feature 146c, rather than being integrated into the structure of the arm link 116 that includes them.

[0081] As can be seen from the figure, the coolant may flow into the third motor cooling feature 146c via one or more coolant flow path segments 120 and then out of the third motor cooling feature 146c via one or more other coolant flow path segments 120.

[0082] In some embodiments, as shown in the alternative Figure 1B', the use of a magnetic fluid seal or other vacuum-rated rotary seal may be combined with additional fluid flow lines for purposes other than cooling or in addition to cooling. For example, in some embodiments, one or more fluid flow lines for providing a purge gas, for example, an inert (either a noble gas or, in many cases, a gas that does not react with process chemicals such as nitrogen) gas, may be routed inside the robotic arm assembly.

[0083] In Figure 1B’, the second rotary joint 112b is enhanced with a purge gas bleed feature that enables the purge gas provided by the purge gas line 184 to be provided to the purge gas plenum 186, which then may distribute the purge gas to one or more purge gas outlets 188 arranged around or centered on the second rotary joint 112b. The purge gas plenum 186 may be, for example, generally annular in shape or may extend around most or all of the circumference of the second rotary joint (e.g., the purge gas plenum may be provided by two arcuate plenums / passages having a common center point and receiving purge gas from corresponding inlets respectively). The purge gas line 184 may be provided by at least partially flexible tubing, such as a coolant flow path segment.

[0084] The three circular cross-sections shown in the lower right of Figure 1B’ illustrate various alternative embodiments of the purge gas bleed feature. The left example is similar to that shown at the left end in Figure 1B’, with a plurality of individual purge gas outlets 188 arranged in a circular array centered outside the shaft portion of the second arm link 116b, such that when the purge gas flows into the purge gas plenum 190, it flows radially outward along the circumference of the shaft portion in the gap between the first arm link 116a and the second arm link 116b near the second rotary joint 112b. Such a purge gas flow may act to protect against potential exposure of the second magnetic fluid seal 124b to process gas residues, which otherwise may contact the second magnetic fluid seal 124b and potentially degrade the second magnetic fluid seal 124b.

[0085] The central cross-section shown in FIG. 1B’ is of a similar design except that instead of the purge gas outlet 188 being provided by a plurality of individual passages arranged around the shaft portion of the second arm link 116b, there is a single purge gas outlet 188 provided by a thin circumferential slit extending between the outside of the shaft portion of the second arm link 116b and the purge gas plenum 186.

[0086] The right cross-section shown in FIG. 1B’ is of a similar design to the leftmost circular cross-section of FIG. 1B except that it has a plurality of purge gas plenums 186 and a plurality of different sets of purge gas outlets 188. For example, the purge gas may be supplied to the first purge gas plenum 186a by the purge gas line 184 and then pass from the first purge gas plenum 186a through the first purge gas outlet 188a and through the second purge gas plenum 186b. The purge gas may then pass from the second purge gas plenum 186b through the second purge gas outlet 188b and through the region around the shaft portion of the second arm link 116b.

[0087] As can be seen from the figures, by using a plurality of purge gas plenums 186 arranged to provide more or less concentric purge gas plenum zones (each plenum zone having an annular plenum or a plurality of arcuate plenums disposed within an annular zone) that are fluidly connected to each other via purge gas outlets extending between two adjacent purge gas plenums, the purge gas being sent thereby can be more evenly circumferentially distributed among the last set of purge gas outlets before being released into the ambient environment around the robotic arm assembly. In such an arrangement, each set of purge gas outlets connecting between two adjacent purge gas plenum zones may be arranged to be equidistantly circumferentially spaced between two adjacent purge gas outlets 188, such that the shortest possible flow path between the purge gas inlet(s) and each outermost purge gas outlet 188 is close to the average of the lengths of such flow paths, resulting in a more even distribution of the purge gas.

[0088] Although the purge gas bleed feature described above has been shown to be realized only in the second rotary joint 112b, it will be understood that similar such features may be realized in any rotary joint of the robotic arm assembly, including all rotary joints of the robotic arm assembly or at least a plurality of rotary joints of the robotic arm assembly.

[0089] FIG. 1C is a detailed view of the third arm link 116c, the fourth arm link 116d, and the fifth arm link 116e. The third arm link 116c includes a fourth motor 162d and a fifth motor 162e, which are shown as being kinematically connected to the fourth arm link 116d and the fifth arm link 116e, respectively. The fourth motor 162d may be configured to drive, for example, a pulley 168d, and the pulley 168d is configured to drive a pulley 168d' via a belt 170d to rotate the fourth arm link 116d relative to the third arm link 116c. Similarly, the fifth motor 162e may be configured to drive, for example, a pulley 168e, and the pulley 168e is configured to drive a pulley 168e' via a belt 170e to rotate the fifth arm link 116e relative to the third arm link 116c.

[0090] As shown in FIGS. 1 and 1C, the fourth motor cooling feature 146d and the fifth motor cooling feature 146e may be arranged to surround or adjacent to the fourth motor 162d and the fifth motor 162e, respectively. These motor cooling features may have characteristics similar to those previously discussed with respect to the third motor cooling feature 146c.

[0091] As described above, the fourth arm link 116d and the fifth arm link 116e may be rotatably connected to the third arm link 116c by a fourth rotary joint 112d and a fifth rotary joint 112e, respectively.

[0092] As can be seen from the figure, the fourth rotary joint 112d includes a pair of rotary bearings 136d and 136d', which support the fourth arm link 116d with respect to the third arm link 116c, for example, via a shaft portion 178d protruding from the lower surface of the main body portion 180d of the fourth arm link 116d. The fourth rotary joint 112d also includes a fourth magnetic fluid seal 124d that seals between the fourth arm link 116d, for example, between the shaft portion 178d protruding from the lower surface of the main body portion 180d of the fourth arm link 116d and the shaft portion 178e protruding from the lower surface of the main body portion 180e of the fifth arm link 116e, thereby sealing the interior of the third arm link 116c against potential leakage through the fourth rotary joint 112d. Similarly, the fifth rotary joint 112e includes a pair of rotary bearings 136e and 136e', which support the fifth arm link 116e with respect to the third arm link 116c, for example, via a shaft portion 178e protruding from the lower surface of the main body portion 180e of the fifth arm link 116e. The fifth rotary joint 112e also includes a fifth magnetic fluid seal 124e that seals between the fifth arm link 116e, for example, between the shaft portion 178e protruding from the lower surface of the main body portion 180e of the fifth arm link 116e and the third arm link 116c, thereby sealing the interior of the third arm link 116c against potential leakage through the fifth rotary joint 112e.

[0093] As described above, the fourth rotary joint 112d and the fifth rotary joint 112e are arranged coaxially. Therefore, the shaft portion 178d actually extends through the shaft portion 178e and projects beyond the end of the shaft portion 178e, thereby enabling the shaft portion 178d to be connected to the pulley 168d'. The shaft portion 178e is rotatably supported with respect to the third arm link 116c by the rotary bearings 136e and 136e', and the shaft portion 178d is rotatably supported with respect to the shaft portion 178e via the rotary bearings 136d and 136d'. Since all of the rotary bearings 136d, 136d', 136e, and 136e' are arranged to have a common rotation axis, such an arrangement effectively enables both the fourth arm link 116d and the fifth arm link 116e to rotate with respect to both the third arm link 116c and each other by the fourth rotary joint 112d and the fifth rotary joint 112e, respectively.

[0094] As shown in FIGS. 1 and 1C, the fourth arm link 116d and the fifth arm link 116e each house their respective sensors 172a and 172b. The sensor 172 may be, for example, an optical sensor such as an image sensor. Each sensor 172 may be configured to acquire data (e.g., an image) from the area below the sensor. For example, such a sensor 172 may be used to acquire image data regarding components inside the semiconductor processing chamber, such as an image of a reference placed on such a component, and this image may assist the robot arm system in calibrating regarding where such a component is placed relative to the robot arm base 108. Also, such a sensor may be used to acquire data regarding other aspects of the chamber, such as the condition of a pedestal or an edge ring installed inside the chamber. It will be understood that the sensor 172 may similarly or alternatively be placed inside the robot arm links 116d and 116e in other orientations, for example, upward or outward instead of downward. With such a configuration, the sensor 172 may be enabled to acquire data regarding components or features such as chamber walls or showerheads that may be present inside such a processing chamber.

[0095] Also visible in FIGS. 1 and 1C are the sensor cooling features 148a and 148b. The sensor cooling features 148 may each be placed adjacent to or surrounding a portion of one of the sensors 172. In this example, the sensor cooling features 148a and 148b are cooling blocks through which serpentine cooling channels are routed. The cooling blocks are placed opposite the sensors 172 such that heat from the sensors 172a and 172b is conducted to the sensor cooling features 148a and 148b, respectively. The coolant flowing through the sensor cooling feature 148 may then act to remove heat from the sensor cooling feature 148.

[0096] In a coaxial rotary joint configuration as shown in FIGS. 1 and 1C, routing of coolant flow path segments for cooling features that can be installed inside the arm link 116 supported by the coaxial rotary joint 112 can be difficult. For example, routing the coolant flow path segment 120 connected to the fourth arm link 116d through the center of the shaft portion 178d, then exiting from the top of the shaft portion 178d and entering the inside of the fourth arm link 116d, where it may be possible to fluidly connect such a coolant flow path segment 120 to the cooling feature. However, routing of the coolant flow path segment connected to the cooling feature installed in the fifth arm link 116e can be more difficult. For example, if such a coolant flow path segment also passes through the center of the shaft portion 178d, in order to reach the inside of the fifth arm link 116e, it is necessary to pass through the fifth rotary joint in some way (not axially) in the radial direction.

[0097] To facilitate this, the shaft portion 178d may be provided with an opening (or openings) extending generally radially from the inside of the shaft portion 178d to the outer surface of the shaft portion 178d, thereby enabling routing of the coolant flow path segment 120 from the inside of the shaft portion 178d to the outside of the shaft portion 178d. The opening, such as the opening 182 in FIG. 1C, may be installed such that a magnetic fluid seal that seals between the two coaxial shaft portions 178d and 178e is placed between the opening 182 and the body portion of the fourth arm link 116d. This allows an opening to be installed within the region of the robotic arm assembly 110 that is fluidly isolated from the vacuum environment that can surround the robotic arm assembly 110. This enables the coolant flow path segment 120 to be routed from the inside of the shaft portion 178d of the fourth arm link 116d into the fifth arm link 116e.

[0098] In some examples, the opening 182 may extend by an arc sector centered on the circumference of the shaft portion. For example, the opening 182 may be a radial slot that extends along an arc of the same radius relative to the outer surface of the shaft portion 178d, for example, at an arc angle of at least 45°, at least 60°, at least 75°, at least 90°, at least 115°, at least 130°, or at least 180°. Such a slot may provide clearance, thereby allowing the shaft portion 178d and the shaft portion 178e to rotate relative to each other without causing excessive shear stress in the coolant flow path segment 120 passing through the opening 182. The sector of the arc over which the opening extends may be selected to be, for example, the same as the sector of the arc over which the fourth arm link 116d and the fifth arm link 116e swing relative to each other during normal use.

[0099] FIG. 1C’ shows an alternative embodiment that includes an additional cooling feature type, namely an arm link cooling feature. As shown in FIG. 1C’, which depicts a detailed view of the region indicated by C’ in FIG. 1C, the fourth arm link 116d includes an arm link cooling feature 151. The arm link cooling feature 151 is, in this example, a cooling block having one or more coolant passages inside which coolant is supplied from the corresponding coolant flow path segments 120a and 120b. The coolant passages may follow a serpentine path inside the cooling block as shown. In other embodiments, such coolant passages may be formed (e.g., machined) directly in the material of the arm link itself. The arm link cooling feature 151 may, in some cases, extend along the entire length of the arm link, or alternatively, only along a portion thereof, such as the half of the arm link closest to the end effector(s). The arm link cooling feature 151 may also extend along the bottom and / or side surfaces of the arm link.

[0100] The arm link cooling feature 151 is shown in FIG. 1C' as existing on only one arm link, but it will be understood that such an arm link cooling feature may be implemented in additional or other arm links, such as all arm links or a subset thereof. With such a cooling feature, the robot arm assembly can cause its components to dissipate heat that can be transferred, for example, by handling a wafer at an elevated temperature. For example, when using a robot arm assembly to pick a wafer that is still quite hot, such as at 200 °C or higher, 300 °C or higher, and / or 400 °C or higher, the heat radiated and conducted from these wafers may be transmitted to the end effector carrying the wafer and then to the arm link via conduction. Since such a robot arm assembly can generally operate in a vacuum environment, it may be difficult for the robot arm assembly to dissipate the heat transferred thereto to the surrounding atmosphere. Thus, the arm link cooling feature may provide a valuable ability to cool a robot arm assembly used in a vacuum environment and / or a robot arm assembly used when transferring hot wafers.

[0101] The features described above with respect to the various cooling features and components that are cooled internally within the robotic arm assembly of FIGS. 1-1C will be understood to be realizable in a variety of situations. For example, a portion of the robotic arm assembly may include only the magnetic fluid seal cooling feature, while others may include only the sensor cooling feature. The robotic arm assembly does not necessarily have all four types of cooling features described above with respect to FIGS. 1-1C, and robotic arm assemblies having the following are also considered within the scope of the present disclosure: only the magnetic fluid seal cooling feature, only the motor cooling feature, only the sensor cooling feature, only the arm link cooling feature, only the magnetic fluid seal cooling feature and the motor cooling feature, only the magnetic fluid seal cooling feature and the arm link cooling feature, only the magnetic fluid seal cooling feature and the sensor cooling feature, only the motor cooling feature and the arm link cooling feature, only the sensor cooling feature and the arm link cooling feature, only the magnetic fluid seal cooling feature, the motor cooling feature, and the sensor cooling feature, only the magnetic fluid seal cooling feature, the motor cooling feature, and the arm link cooling feature, only the magnetic fluid seal cooling feature, the sensor cooling feature, the sensor cooling feature, or only the arm link cooling feature, only the motor cooling feature, the sensor cooling feature, or only the arm link cooling feature. It will also be understood that cooling features other than the specific examples discussed herein may be included in such robotic arm assemblies. Further, the concepts discussed herein with respect to the exemplary robotic arm assembly 110 of FIGS. 1-1C will be understood to be realizable in robotic arm assemblies having a single arm link, two arm links, three arm links, four arm links, five arm links, six arm links, seven arm links, eight arm links, nine arm links, etc. Also, if desired, it will be understood that a vacuum-compatible seal other than the magnetic fluid seal discussed herein may be used in place of the magnetic fluid seal.

[0102] In the above discussion, coolant flow path segments are referred to without normally distinguishing between an inlet coolant flow path segment and an outlet coolant flow path segment, because the nature of a particular coolant flow path segment may vary depending on the situation in which it is viewed. For example, in the examples of FIGS. 1-1C, all of the coolant flow path segments 120a may be used to supply coolant to various cooling features within the shown robotic arm assembly 110, and all of the coolant flow path segments 120b may be used to return coolant from those same cooling features (or vice versa). In the examples of FIGS. 1-1C, the coolant flow path segments 120a are normally arranged in parallel with the coolant flow path segments 120b, such that each coolant flow path segment 120 serves only one purpose with respect to supplying coolant to or returning coolant from the cooling features. However, other arrangements, such as where coolant is sent serially to multiple cooling features, may have coolant flow path segments that serve multiple purposes. For example, a single coolant flow path segment may function as a coolant supply to a cooling feature that is "downstream" of the coolant flow path segment and as a coolant return from another cooling feature that is "upstream" of the coolant flow path segment.

[0103] FIG. 4, including FIGS. 4A, 4B, and 4C, shows options for routing various coolant flow path segments, such as options that may be used for supplying coolant to and receiving coolant from cooling features of a robotic arm assembly.

[0104] Figure 4 shows an exemplary robot arm assembly 410. The exemplary robot arm assembly 410 includes a first arm link 416a, a second arm link 416b, a third arm link 416c, and a fourth arm link 416d. The first arm link 416a is rotatably connected to a robot arm base (not shown) via a first rotary joint 412a and is rotatably connected to the second arm link 416b via a second rotary joint 412b. Similarly, the third arm link 416c is rotatably connected to the second arm link 416b via a third rotary joint 412c and is rotatably connected to the fourth arm link 416d via a fourth rotary joint 412d. At different positions within the robot arm assembly 410, a number of cooling features 442 are disposed, including, for example, a first cooling feature 442a and a second cooling feature 442b of the first arm link 416a, a third cooling feature 442c of the second arm link 416b, and a fourth cooling feature 442d of the third arm link 416c.

[0105] In Figure 4, coolant flow path segments are represented by lines with triangles indicating the flow direction, which connect to various cooling features and are routed through the rotary joints 412.

[0106] In Figure 4A, it can be seen that one coolant flow path segment fluidly connects to an inlet to the cooling feature 442d through three rotary joints 412a - 412c. Further, it can be seen that additional coolant flow path segments fluidly connect the outlets of each of the three cooling features 442d - 442b to the inlets of the cooling features 442c - 442a "downstream" thereof. The coolant flow path segment leading from the outlet of the first cooling feature 442a may, for example, exit the robot arm assembly 410 via the robot arm base and flow into an external heat exchanger or other heat dissipation system. Thus, the four cooling features 442 are fluidly connected in series.

[0107] In FIG. 4B, it can be seen that there are two main coolant flow path segments that extend from the first rotary joint 412a through the second rotary joint 412b and the third rotary joint 412c and are fluidly connected to the cooling feature 442d, allowing the coolant to circulate through the cooling feature 442d. Additional coolant flow path segments are shown that branch off from these two main coolant flow path segments and connect to the cooling features 442c and 442a and 442b. Thus, the coolant is sent in parallel to the cooling features 442a, 442c, and 442d. However, the cooling features 442a and 442b are fluidly connected in series. Thus, the coolant flow path segments may be arranged to fluidly connect to the cooling features in parallel and / or series fashion.

[0108] In FIG. 4C, it can be seen that for each of the cooling features 442a - 442d, a completely separate coolant flow path segment is provided. Such an arrangement allows the coolant to be sent to the different cooling features 442 at different rates (which may be varied as desired by using a flow metering device or valve), but may require more space than the two - flow - path embodiment in other examples due to an increase in the amount of hardware required to route eight separate flow paths through the first rotary joint 412a.

[0109] As described above, the wafer handling robot as described above may be used in a VTM. FIG. 5 is a diagram of a VTM 502 in which a plurality of processing chambers 504 are attached via, for example, a slit valve or other closable opening (not shown). A wafer handling robot having a robot arm assembly 510 and a robot arm base 508 may be attached to the VTM 502, whereby the robot arm base 508 is attached to the outside of the VTM 502 and the robot arm assembly 510 is installed inside the VTM 502, for example, within a vacuum environment. The robot arm assembly 510 may include, for example, a magnetic fluid seal and cooling features as discussed with respect to the examples described earlier herein.

[0110] The present disclosure has focused on a robot that can incorporate a magnetic fluid seal or other vacuum-compatible rotary seal technology to keep the interior of the robot arm at atmospheric (or at least higher) pressure, thereby facilitating the use of flexible cooling lines inside the robot arm and enabling fluid cooling of components inside the robot arm. As an example of such a robot, a wafer handling robot is described, but it will be understood that the principles and concepts discussed herein may also be applied to robot arms used under vacuum conditions for other purposes. The present disclosure should be understood to encompass such alternative embodiments as well.

[0111] The control of a wafer handling robot as described herein may be facilitated by using a controller that may be included as part of a semiconductor processing tool having the wafer handling robot or may be integrated into the wafer handling robot itself. The system described above may be integrated with electronics for controlling the operation of the system before and after processing of a semiconductor wafer or substrate. This electronics may be referred to as a "controller" that may control various components or sub-components of the system(s). The controller may be programmed to control any of the systems disclosed herein, including the operation of various motors and / or sensors that may be incorporated into, for example, a wafer handling robot, depending on the processing requirements and / or the type of system.

[0112] Broadly speaking, the controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that, for example, receive commands, issue commands, control operations, enable cleaning operations, enable endpoint measurement, etc. The integrated circuits may include chips in the form of firmware that stores program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors or microcontrollers that execute program instructions (such as software). The program instructions may be instructions transmitted to the controller in the form of various individual settings (or program files) that define the operating parameters for performing specific wafer transfer operations within a VTM using the wafer handling robot disclosed herein.

[0113] The controller may, in some embodiments, be part of a computer integrated with, coupled to, or otherwise network-connected to the system, or may be coupled to such a computer, or may be a combination thereof. For example, the controller may be all or part of a host computer system within a "cloud" or a manufacturing plant that enables remote access to wafer processing. This computer can monitor the current progress of manufacturing operations, verify the history of past manufacturing operations, and verify trends or performance criteria from multiple manufacturing operations to change the parameters of the current process, set the process steps following the current process, or start a new process by enabling remote access to the system. In some examples, a remote computer (e.g., a server) can provide a process recipe to the system through a network that may include a local network or the Internet. The remote computer may include a user interface that enables input or programming of parameters and / or settings, and the parameters and / or settings are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in a data format that defines the parameters of each process step performed during one or more operations. It should be understood that this parameter may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by including one or more separate controllers network-connected to each other and working towards a common purpose such as the processes and controls described herein. Examples of controllers distributed for such a purpose include one or more integrated circuits combined to control wafer transfer operations in a VTM using a wafer handling robot and communicating with, for example, one or more integrated circuits on a chamber such as a VTM, which are remotely installed (e.g., at the platform level or as part of a remote computer).

[0114] Although not limited, an exemplary VTM having a wafer handling robot, such as those discussed herein, may be connected to one or more other devices, such as a plasma etching chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etching chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etching (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, or any other semiconductor processing system that may be associated with or used in the manufacture and / or production of semiconductor wafers.

[0115] As described above, depending on one or more process steps performed by a tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools installed throughout the factory, a main computer, other controllers, or tools used for material transport that load and unload containers of wafers, such as FOUPs, to and from tool positions and / or load ports within a semiconductor manufacturing facility.

[0116] For the purposes of the present disclosure, the term "fluidly connected" is used for volume portions, plenums, holes, etc. that can be connected to each other directly or via one or more intervening components or volume portions to form a fluid connection, in the same way that the term "electrically connected" is used for components that are interconnected to form an electrical connection. When the term "fluidly interposed" is used, it may be used to refer to a component, volume portion, plenum, or hole that is fluidly connected to at least two other components, volume portions, plenums, or holes, and through which fluid flowing from one of these other components, volume portions, plenums, or holes to another of the other components, volume portions, plenums, or holes first flows through the "fluidly interposed" component before reaching the other of the other components, volume portions, plenums, or holes. For example, if a pump is fluidly interposed between a reservoir and an outlet, the fluid flowing from the reservoir to the outlet first flows through the pump before reaching the outlet. When the term "fluidly adjacent" is used, it refers to positioning a fluid element relative to another fluid element such that no structure that could potentially impede the flow of fluid between the two fluid elements is fluidly interposed between the two elements. For example, in a flow path in which a first valve, a second valve, and a third valve are sequentially positioned along the flow path, the first valve is fluidly adjacent to the second valve, the second valve is fluidly adjacent to both the first valve and the third valve, and the third valve is fluidly adjacent to the second valve.

[0117] In this disclosure and the claims, when ordinal numbers are used, such as (a), (b), (c)… or (1), (2), (3)… etc., it should be understood that they do not convey a particular order or sequence, unless such order or sequence is explicitly indicated. For example, if there are three steps labeled (i), (ii), (iii), these steps may be performed in any order (or simultaneously if not prohibited) unless otherwise instructed. For example, if step (ii) involves the handling of an element created in step (i), step (ii) may be considered to occur at some point after step (i). Similarly, if step (i) involves the handling of an element created in step (ii), the reverse should be understood. Also, in this specification, when using the ordinal number "first" as in "the first item", it should be understood that it is not to be construed as implicitly or inherently suggesting the necessary existence of a "second" instance, such as "the second item".

[0118] As used herein, expressions such as "for each / every <item> of one or more <items>", "each / every <item> of one or more <items>" etc. include both a single group of items and multiple groups of items, that is, the expression "for each / every..." should be understood to be used in the sense in which it is used in a programming language to refer to each item, regardless of what the group of items being referred to is. For example, if the group of items being referred to is a single item, "each / every" refers only to that single item (even though in the dictionary definition of "each / every", "each / every" is often defined as a term that refers to "each one of two or more things"), and it does not mean that there must be at least two such items. Similarly, the terms "set" or "subset" should not, in themselves, necessarily be regarded as encompassing multiple items. A set or subset may be understood to be able to include only one member, or multiple members (in the absence of other indications in the context).

[0119] As used herein, the term "between" when used with a range of values is understood to include the starting and ending values of that range, unless otherwise indicated. For example, it should be understood that between 1 and 5 includes not only the numbers 2, 3, and 4, but also the numbers 1, 2, 3, 4, and 5.

[0120] The term "operatively connected" is understood to refer to a state in which two components and / or systems are connected, either directly or indirectly, such that, for example, at least one of the components or systems can control the other component or system. For example, a controller may be described as being operatively connected to a resistive heating unit, which includes the controller being connected to a sub-controller of the resistive heating unit. The sub-controller is electrically connected to a relay, which is configured to be controllable to connect or disconnect the resistive heating unit and a power source, and the power source is configured to provide an amount of power to the resistive heating unit that can supply power to produce a desired degree of heating. Although the controller itself may not be able to directly supply such power to the resistive heating unit due to the associated current, the controller is still understood to be operatively connected to the resistive heating unit.

[0121] The examples and embodiments described herein are for illustrative purposes only, and it is understood that various modifications or changes are suggested to those skilled in the art in view of them. Although various details have been omitted for clarity, various design alternatives may be implemented. Therefore, this example is considered to be illustrative and not restrictive, and the present disclosure is not limited to the details shown herein and may be modified within the scope of the present disclosure.

[0122] The above disclosure, while focusing on certain specific embodiments or a plurality of embodiments, is not limited to only the examples described above, but may also be applied to similar variations and mechanisms, and such similar variations and mechanisms should also be understood to be within the scope of the present disclosure.

Claims

1. An apparatus comprising: a robot arm base; a robot arm assembly including one or more arm links and a first set of one or more rotary joints, each of the first set of one or more rotary joints including a corresponding vacuum-compatible seal; a component defining a plurality of coolant flow path segments; a first set of one or more cooling features, each of the first set of one or more cooling features being fluidly connected to at least two of the coolant flow path segments and being fluidly disposed between at least two of the coolant flow path segments; and a base rotary joint of the one or more rotary joints rotatably connecting a first arm link of the one or more arm links to the robot arm base; an apparatus, wherein at least two of the coolant flow path segments extend from the robot arm base, through the base rotary joint, and into at least the first arm link.

2. The apparatus of claim 1, wherein the one or more vacuum-compatible seals include at least a first vacuum-compatible seal; the one or more cooling features include one or more vacuum-compatible seal cooling features; the one or more vacuum-compatible seal cooling features include a first vacuum-compatible seal cooling feature; and the first vacuum-compatible seal cooling feature is configured to cool the first vacuum-compatible seal when coolant flows into the first vacuum-compatible seal cooling feature via at least one of the coolant flow path segments and out of the first vacuum-compatible seal cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

3. The apparatus of claim 2, wherein the first vacuum-compatible seal cooling feature includes a passage extending through at least a portion of a tubular zone having a centerline coaxial with a rotational axis of one of the one or more rotary joints including the first vacuum-compatible seal. An apparatus surrounding one or more faces of the first vacuum-compatible seal that face radially inwardly toward the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal, said tubular zone facing radially inwardly toward the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal.

4. The apparatus according to claim 3, wherein the passage is at least partially bounded by one or more faces of the first vacuum-compatible seal that face radially outwardly from the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal.

5. The apparatus according to claim 2, wherein the first vacuum-compatible seal cooling feature includes a passage extending through at least a portion of a tubular zone having a centerline coaxial with the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal, said tubular zone being surrounded by one or more faces of the first vacuum-compatible seal that face radially inwardly toward the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal.

6. The apparatus according to claim 5, wherein the passage is at least partially bounded by the one or more faces of the first vacuum-compatible seal that face radially inwardly toward the axis of rotation of one of the one or more rotary joints including the first vacuum-compatible seal.

7. The apparatus according to any one of claims 3 to 6, wherein the passage has an annular shape or an annular sector shape.

8. The apparatus according to any one of claims 1 to 7, wherein the robot arm assembly includes a first motor, wherein the one or more cooling features include one or more motor cooling features, wherein the one or more motor cooling features include a first motor cooling feature, wherein the first motor cooling feature is disposed adjacent to or surrounding a portion of the first motor, wherein the first motor cooling feature is configured to cool the first motor when coolant flows into the first motor cooling feature via at least one of the coolant flow path segments and out of the first motor cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

9. The apparatus according to any one of claims 1 to 8, wherein the one or more cooling features include one or more arm link cooling features, wherein the one or more arm link cooling features include a first arm link cooling feature, wherein the first arm link cooling feature is disposed adjacent to or within a material forming one of the one or more arm links, wherein the first arm link cooling feature is configured to cool the first arm link when coolant flows into the first arm link cooling feature via at least one of the coolant flow path segments and out of the first arm link cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

10. The apparatus according to claim 9, wherein the first arm link cooling feature extends along at least half of the length of the arm link made of the material adjacent to or within which the first arm link cooling feature is disposed.

11. The apparatus according to any one of claims 1 to 10, further comprising a first sensor installed within one of the one or more arm links, wherein the one or more cooling features include one or more sensor cooling features, wherein the one or more sensor cooling features include a first sensor cooling feature, wherein the first sensor cooling feature is disposed adjacent to or surrounding a portion of the first sensor, wherein the first sensor cooling feature is configured to cool the first sensor when coolant flows into the first sensor cooling feature via at least one of the coolant flow path segments and out of the first sensor cooling feature via at least one other coolant flow path segment of the coolant flow path segments.

12. The apparatus according to claim 11, wherein the first sensor is an optical sensor.

13. The apparatus according to claim 12, wherein the first sensor is an image sensor.

14. The apparatus according to any one of claims 11 to 13, wherein the one or more arm links include a first end effector arm link having a first end effector. An apparatus, wherein the first sensor is located on the first end effector arm link. **Claim 15** The apparatus according to claim 14, wherein the first sensor is directed to collect data from a position below the first end effector arm link. **Claim 16** The apparatus according to claim 14, wherein the first sensor is directed to collect data from a position above the first end effector arm link. **Claim 17** The apparatus according to any one of claims 14 to 16, wherein the first end effector arm link is also the first arm link. **Claim 18** The apparatus according to any one of claims 14 to 16, further comprising a second sensor, wherein the one or more arm links further comprise a second end effector arm link having a second end effector, wherein the second sensor is installed inside the second end effector arm link, wherein the one or more arm links further comprise a forearm link, wherein the first end effector arm link is rotatably connected to the forearm link by a first rotary joint among the one or more rotary joints, wherein the second end effector arm link is rotatably connected to the forearm link by a second rotary joint among the one or more rotary joints, wherein the one or more sensor cooling features include a second sensor cooling feature, wherein the second sensor cooling feature is disposed adjacent to or surrounding a part of the second sensor, wherein the second sensor cooling feature is configured to cool the second sensor when coolant flows into the second sensor cooling feature via at least one of the coolant flow path segments and then flows out of the second sensor cooling feature via at least one other coolant flow path segment of the coolant flow path segments. **Claim 19** The apparatus according to claim 18, wherein the first rotary joint is configured such that the first end effector arm link can rotate about a first rotation axis with respect to the forearm link, wherein the second rotary joint is configured such that the second end effector arm link can also rotate about the first rotation axis with respect to the forearm link. The first end effector is disposed at a higher altitude than the second end effector, The first end effector link includes a first body portion and a first shaft portion, The first shaft portion extends through the second end effector link, The first shaft portion is supported by the first rotary joint, The first rotary joint includes a first vacuum-compatible seal that seals between the second end effector link and the first portion of the first end effector link, Both the second sensor and the second sensor cooling feature are installed inside the second arm link at a position radially outside the first vacuum-compatible seal with respect to the first rotation axis, The device, wherein the first vacuum-compatible seal is disposed between the first body portion and a position on the first shaft portion where a coolant flow path segment leading to the second sensor cooling feature exits from the first portion.

20. The device according to claim 19, An opening extends through the first shaft portion over a sector of an arc centered on the first rotation axis, The device, wherein the coolant flow path segment leading to the second sensor cooling feature exits from the first shaft portion via the opening.

21. The device according to claim 20, The device, wherein the sector of the arc extends at least 90°.

22. The device according to any one of claims 1 to 16, The device, wherein the one or more arm links include a plurality of arm links.

23. The device according to claim 22, A second rotary joint rotatably connects two of the plurality of arm links, At least two of the coolant flow path segments pass through the base rotary joint, The device, wherein at least two of the coolant flow path segments pass through the second rotary joint.

24. The device according to any one of claims 1 to 23, The device, wherein at least some of the coolant flow path segments are at least partially provided by flexible polymer tubing.

25. The device according to any one of claims 1 to 24, An apparatus, wherein each of the components defining the flow path segment includes one or more components selected from a length portion of a flexible polymer pipe, a length portion of a rigid pipe, a flow splitting device, a through connector, and a connecting fitting.

26. The apparatus according to any one of claims 1 to 25, further comprising a purge gas bleed feature, wherein the purge gas bleed feature includes one or more purge gas outlets fluidly connected to one or more purge gas plenums and configured to direct purge gas from the one or more purge gas plenums radially outwardly proximate to a corresponding one of the one or more rotary joints. An apparatus, wherein one or more purge gas lines are routed from the robot arm base, through the base rotary joint, and into at least the first arm link.

27. The apparatus according to any one of claims 1 to 26, wherein at least one of the one or more rotary joints includes a corresponding vacuum-compatible seal that is a magnetic fluid seal.

28. The apparatus according to any one of claims 1 to 27, wherein each of the rotary joints includes a corresponding vacuum-compatible seal that is a magnetic fluid seal.

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