Blade-type end effector with angular compliance mechanism

Abstract

Disclosed herein is a wafer handling robot and associated system that provides a blade-type end effector having a built-in compliance mechanism that allows the end effector blade to rotate a small amount due to gravity loads relative to the wrist unit housing of the end effector wrist unit, both in a first configuration and in a second configuration in which the wrist unit housing is turned upside down from the first configuration. Such a system may be used in conjunction with end effector blades made of a high stiffness material, such as silicon carbide, to allow such end effector blades to be used in conditions that would normally require end effector blades made of a softer material.

Description

[Technical field]

[0001] Related Applications The PCT Request Form is being filed contemporaneously herewith as a part of this application. Each application to which this application claims benefit or priority as identified in the contemporaneously filed PCT Request Form is hereby incorporated by reference in its entirety for all purposes. [Background technology]

[0002] Wafer handling robots may use a variety of different types of end effectors to handle semiconductor wafers. Such end effectors may include, for example, blade-type end effectors, which are typically long, thin, metal spatula-like structures designed to support a semiconductor wafer from below. Such end effectors are typically very thin, e.g., only a few mm thick, so that they can slide between wafers arranged in a vertical stack with 10 mm spacing between wafer centers.

[0003] Disclosed herein is an improved wafer handling robot with a blade-type end effector. Summary of the Invention

[0004] The details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims.

[0005] In some implementations, an apparatus may be provided that includes a wrist unit for an end effector. The wrist unit for an end effector may include a wrist unit housing, an end effector mount assembly having a first end effector mount, and one or more rotational interfaces. The first end effector mount may be configured to mechanically couple with a first end effector blade having a major surface defining a first plane, and the end effector mount assembly may be connected to the wrist unit housing via the one or more rotational interfaces such that the end effector mount assembly is rotatable about a first axis through a first angular range of motion relative to the wrist unit housing, and the first axis may be substantially parallel to the first plane when the first end effector is attached to the first end effector mount.

[0006] In some implementations, the first end effector mount may have a first flat end effector mounting surface configured to mate with the first end effector blade and to mate with the first end effector blade when the first flat end effector mounting surface is parallel to the first axis.

[0007] In some implementations, the apparatus may further include a first end effector blade.

[0008] In some implementations, the device may include a first positive stop and a second positive stop, the first positive stop positioned to contact a portion of the end effector mount assembly when the end effector mount assembly is at a first rotational limit of the first angular range of motion, and the second positive stop positioned to contact a portion of the end effector mount assembly when the end effector mount assembly is at a second rotational limit of the first angular range of motion.

[0009] In some such implementations, one or both of the first positive stop and the second positive stop may be adjustable.

[0010] In some implementations, the first angular range of motion may be less than 10 degrees.

[0011] In some implementations, the device may further include a damper mechanism configured to dampen rotational movement of the end effector mount assembly relative to the wrist unit housing.

[0012] In some implementations, the apparatus may further include a draw link and a rocker arm. The draw link may have a first end rotatably coupled to the first end of the rocker arm such that the draw link is rotatable about a second axis relative to the rocker arm, and a second end rotatably coupled to the end effector mount assembly such that the draw link is rotatable about a third axis of the end effector mount assembly. The rocker arm may also have a second end rotatably coupled to the first end of the damper mechanism such that the draw link is rotatable about a fourth axis relative to the damper mechanism, and may be mounted such that the draw link is rotatable about a fifth axis fixed relative to the wrist unit housing.

[0013] In some implementations, a first distance between the fifth axis and the fourth axis may be greater than a second distance between the fifth axis and the second axis.

[0014] In some such implementations, the first distance may be at least 1.5 times the second distance.

[0015] In some implementations, the apparatus may further include a second end effector blade fixed relative to the end effector mount assembly.

[0016] In some implementations, the first and second end effector blades may each have a corresponding distal end and a corresponding proximal end, the proximal ends of the first and second end effector blades may be fixedly attached to the end effector mount assembly, and the distal ends of the first and second end effector blades may each have a corresponding distal cleat attached thereto, each distal cleat may have a riser portion extending away from the corresponding end effector blade and a catch surface extending outwardly from the respective riser portion, and each catch surface may be spaced apart from the corresponding end effector blade by at least a first gap distance.

[0017] In some implementations, each catch surface may be angled away from the corresponding end effector blade such that the catch surface increases in distance from the riser portion from which it extends.

[0018] In some such implementations, the device may further include an actuator mechanism and a proximal cleat. The actuator mechanism may have a first portion and a second portion, the first portion of the actuator mechanism may be fixed relative to the end effector mount assembly, the second portion of the actuator mechanism may be configured to be movable relative to the first portion of the actuator mechanism between a first configuration and a second configuration, the proximal cleat may be fixed relative to the second portion of the actuator mechanism and may have a catch surface that faces substantially the same direction as the catch surface of the distal cleat, the catch surface of the proximal cleat and the catch surface of the distal cleat may not overlap the first reference circle when the second portion of the actuator mechanism is in the first configuration, and the catch surface of the proximal cleat and the catch surface of the distal cleat may all overlap the second reference circle when the second portion of the actuator mechanism is in the second configuration, and the first reference circle and the second reference circle may have the same diameter.

[0019] In some implementations, the first reference circle may have a diameter selected from the group consisting of 200 mm, 300 mm, and 450 mm.

[0020] In some implementations, the wrist unit for the end effector may be configured such that when the wrist unit for the end effector is positioned in a first orientation in which the first axis is horizontal and the first plane is substantially horizontal, the end effector mount assembly moves under gravity load alone to a first rotational limit of the first angular range of motion, and when the wrist unit for the end effector is positioned in a second orientation opposite the first orientation, the end effector mount assembly also moves under gravity load alone to a second rotational limit of the first angular range of motion.

[0021] In some implementations, the first end effector blade may be made of a ceramic material.

[0022] In some such implementations, the first end effector blade may be made of silicon carbide.

[0023] In some implementations, the apparatus may further include a base, one or more robotic arm links, and a wrist drive unit. The one or more robotic arm links may include a first robotic arm link configured to be rotatable relative to the base about a base axis, the wrist drive unit may be supported by the one or more robotic arm links and may include a wrist mount rotatable about an axis perpendicular to an axis parallel to the base axis, and the wrist unit for the end effector may be mounted to the wrist mount.

[0024] In some implementations, an apparatus may include a base, one or more robotic arm links, and a wrist drive unit. The one or more robotic arm links may include a first robotic arm link configured to be rotatable relative to the base, the wrist drive unit may be supported by the one or more robotic arm links and may include a wrist mount rotatable about an axis perpendicular to the first axis, and the wrist unit for the end effector may be mounted to the wrist mount.

[0025] In some implementations, a method may be provided that includes: a) moving an end effector wrist unit to a first position relative to a wafer mounted on a pedestal, the end effector wrist unit supporting one or more end effector blades rotatably mounted to the end effector wrist unit using one or more rotation interfaces (the one or more end effector blades may be rotatable about a first axis relative to the end effector wrist unit and the one or more end effector blades may have distal cleats mounted to one or more distal ends thereof); b) lowering the end effector wrist unit from the first position to a second position where the distal cleats first contact the pedestal; and c) further lowering the end effector wrist unit from the second position to a third position, thereby rotating the one or more end effector blades about the first axis relative to the end effector wrist unit.

[0026] In some implementations of the method, when in the third position, the proximal cleat supported by the wrist unit for the end effector may be positioned such that the catch surface is located such that at least a portion of the catch surface is at a lower height relative to the normal vector of the wafer than the edge of the wafer.

[0027] In some implementations of the method, the method may further include moving at least one of the distal cleat and the proximal cleat radially inward relative to the wafer such that the catch surfaces of the proximal cleat and the catch surfaces of the distal cleat all overlap the wafer when viewed along an axis perpendicular to the wafer.

[0028] In some further such implementations, the method may further include lifting the wafer off the pedestal by moving at least one of the distal cleat and the proximal cleat radially inward relative to the wafer and then raising the end effector wrist unit a fourth distance.

[0029] In some additional such implementations, the method may further include, after raising the wrist unit for the end effector the fourth distance, rotating the wrist unit for the end effector 180 degrees about a second axis perpendicular to the first axis and substantially parallel to the wafer.

[0030] In addition to the implementations listed above, other implementations apparent from the following discussion and drawings should all be understood to be within the scope of the present disclosure.

[0031] In the following discussion, reference will be made to the following drawings, which are not intended to be limiting in scope, but are provided solely to facilitate the following discussion: [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is an isometric view of an example apparatus having a wafer handling robot.

[0033] [Figure 2-1] 1A-1D are side views of an exemplary end effector wrist unit and end effector blade in various operating states; [Figure 2-2]1A-1D are side views of an exemplary end effector wrist unit and end effector blade in various operating states; [Figure 2-3] 11A-11C are side views illustrating an example end effector wrist unit and end effector blade in various alternative operating states.

[0034] [Diagram 3] FIG. 2 is an exploded view of an exemplary end effector wrist unit and end effector blade.

[0035] [Figure 4] FIG. 1 is an isometric view of an exemplary end effector wrist unit and end effector blade.

[0036] [Diagram 5] 5A-5C illustrate the example wrist unit for the end effector of FIG. 4 in different operational configurations.

[0037] [Figure 6] FIG. 2 is a cross-sectional view of an exemplary wrist unit for an end effector.

[0038] [Figure 7] 1A-1D are side views illustrating an example end effector wrist unit and end effector blade at various stages of a wafer pick-up operation. [Figure 8] 1A-1C are side views illustrating an example end effector wrist unit and end effector blade at various stages of a wafer pick-up operation. [Figure 9] 1A-1C are side views illustrating an example end effector wrist unit and end effector blade at various stages of a wafer pick-up operation. [Figure 10] 1A-1D are side views illustrating an example end effector wrist unit and end effector blade at various stages of a wafer pick-up operation. [Figure 11]1A-1D are side views illustrating an example end effector wrist unit and end effector blade at various stages of a wafer pick-up operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] One particular type of blade-type end effector that may be used in some semiconductor processing tools may be configured to hold a semiconductor wafer from both the bottom and the top. For example, such an end effector may support a semiconductor wafer from the bottom and then rotate 180° about the wrist axis of the wafer handling robot so that the end effector is positioned above the semiconductor wafer, which is supported by a cleat that may have a catch surface that overlaps the semiconductor wafer when viewed along an axis perpendicular to the semiconductor wafer, for example. Such an end effector may be used to flip a wafer 180° (from top to bottom or vice versa) during some wafer placement operations.

[0040] When a wafer is picked up by an end effector positioned below the wafer, the wafer may be lifted off the wafer support of the semiconductor processing chamber by a lift pin mechanism or may be suspended in air, for example by having its outermost edge engaged with a wafer support ledge of a Front Opening Integrated Pod (FOUP) or similar structure, so that the end effector can be inserted below the wafer, which is then lowered onto the end effector or moved vertically upward to lift the wafer off the structure supporting it. Once the wafer is placed on the end effector, the end effector may be moved and the wafer may move with it if the speed of the end effector is controlled to avoid slippage.

[0041] When picking up a wafer with an end effector positioned above the wafer, a different strategy may be pursued. For example, the wafer support or other structure on which the wafer rests may have one or more depressions or recesses around the circumference of the wafer that may line up with corresponding distal cleats on the end effector blade. The end effector blade may be angled slightly downward and lowered so that the distal end of the end effector blade, and thus the distal cleat located thereon, contacts the wafer support or other structure. The end effector wrist unit, to which the proximal end of the end effector blade may be attached, may then continue to be lowered until a proximal cleat on the opposite side of the wafer from the distal cleat (e.g., sandwiched between the wafer and the end effector wrist unit) lines up with the wafer edge, so that as the proximal cleat is moved radially inward toward the wafer center (and optionally as the end effector and distal cleats are moved in opposite directions), the proximal and distal cleats may engage the wafer, with their catch surfaces sliding under the wafer edge to act to support the wafer from below. During such further downward movement, the end effector blade, which may be made of titanium or other flexible material, may flex slightly to accommodate continued downward movement of the end effector relative to the wafer support, with the distal cleat remaining pressed against the wafer support.

[0042] However, the inventors have determined that in some semiconductor processing tools, semiconductor wafers processed by the semiconductor processing tools may experience wafer bow, i.e., bowing due to internal stresses developed within the wafer during processing, causing the wafer to distort or bend slightly, and in some cases, the wafer may bend enough that the center of the wafer may be displaced in a direction perpendicular to the wafer surface, in some cases approximately as much as the thickness of the wafer. Thus, for example, a 0.775 mm wafer may bow near the center of the wafer by approximately 0.8 mm. In some cases, even more bowing may occur than the wafer is subjected to. As a result, when such wafers are placed in a vertical stack (e.g., with a nominal pitch between wafers of 10 mm), the actual minimum distance between the closest points of adjacent wafers may be as small as about 7.6 mm, compared to the usual approximately 9.2 mm. The inventors have determined that in order to preserve various clearance tolerances between the end effector and the wafers of the wafer stack, it may be necessary to reduce the thickness of components, such as the end effector blades, to preserve those clearance tolerances. However, the inventors have also determined that doing so may result in the end effector blade being unacceptably thin, i.e., so thin that it would flex too much or potentially permanently deform under the weight of the wafer.

[0043] To alleviate this problem, the inventors have determined that instead of using a metallic material, such as titanium, for the end effector blade, the end effector blade can instead be made from a material with a higher elastic modulus, such as a ceramic, such as aluminum nitride, silicon carbide, or aluminum oxide, for example, in some implementations, a material having an elastic modulus of 250 GPa or greater. By using such a material, the end effector blade may be made thinner without necessarily flexing more than can be tolerated, thereby allowing the play tolerance between the end effector and the wafer to be maintained even when the wafer is subjected to bowing.

[0044] However, the inventors have also determined that the use of such alternative materials in end effector blades may prove problematic for end effectors operating as described above, for example, capable of picking up a wafer from the top or bottom. In particular, end effector blades made of ceramic materials may not be able to flex to the extent that titanium and other metals flex, and therefore may not be able to accommodate the flexures described above. As a result, such end effector blades may break when the cleats at their distal ends are pressed into the wafer support and bending loads are developed within the end effector blade.

[0045] To address this issue, the inventors have devised a wrist unit for an end effector in which the end effector mount assembly can pivot relative to a wrist unit housing of the wrist unit for an end effector. For example, the end effector mount assembly may be rotatably coupled to the wrist unit housing using one or more rotation interfaces, such that the end effector mount assembly can rotate relative to the wrist unit housing about a first axis parallel to a surface on which the end effector supports the wafer. Such rotation interfaces may, for example, cooperate with one or more stop structures to allow the end effector mount assembly to undergo such rotation to a very limited angle, for example, on the order of 10°, 9°, 8°, 7°, 6°, 5°, 4°, or 3° or less, for example, 3° or less.

[0046] For example, when a wrist unit for an end effector is positioned in a first orientation with the end effector blade approximately parallel to the ground, the end effector mount assembly may rotate to a first position relative to the wrist unit housing solely due to the force of gravity acting on the end effector blade (and possibly assisted by the additional weight of the wafer). However, when the same wrist unit for an end effector is flipped into a second orientation opposite the first orientation, the end effector mount assembly may rotate to a second position relative to the wrist unit housing solely due to the force of gravity acting on the end effector blade (and possibly assisted by the additional weight of the wafer).

[0047] Such a rotational interface may be used to provide a certain amount of compliance between the position of the distal cleat at the distal end of the end effector and the wrist unit housing, thereby allowing the distal cleat of the end effector to remain in contact with the wafer support (and avoid bending the end effector blade) while the wrist unit for the end effector can continue to be lowered to bring the proximal cleat into a position where it can engage the edge of the wafer.

[0048] An example wafer handling robot is shown in Figure 1. In Figure 1, an apparatus 100 is shown that may include or be, for example, a wafer handling robot. The apparatus 100 may include a base 190, one or more robot arm links 192, a wrist drive unit 194, an end effector wrist unit 102, and one or more end effector blades 112 / 114. Also shown in Figure 1 is a wafer 101 that may be transported using the wafer handling robot.

[0049] The base 190 may include one or more motors and other equipment that may be used to move other elements of the wafer handling robot, e.g., to rotate the robot arm links 192, e.g., relative to the base 190, thereby causing, for example, the entire robot arm, end effector wrist unit 102, and end effector blades 112 / 114 to rotate about the base 190 and / or relative to the base 190 and each other, e.g., to cause the end effector wrist unit 102 to extend radially inward or outward relative to the base 190.

[0050] Each robot arm link 192 may be considered as having a first end and a second end, with the first end rotatably coupled to either the base 190 or another robot arm link 192, and the second end rotatably coupled to either another robot arm link 192 or the wrist drive unit 194. Each such rotatable connection allows the two elements connected thereby to rotate relative to one another about a rotation axis, such as rotation axis A, B, or C. The wrist drive unit 194 may have a motor or other drive system therein configured to impart rotational motion about rotation axis D to the end effector wrist unit 102. The rotation axis D is, for example, perpendicular to an axis parallel to the rotation axes A, B, and / or C.

[0051] The wrist drive unit 194 may be controlled to flip the end effector wrist unit 102 between two orientations 180° apart by rotating the end effector wrist unit 102 about the rotation axis D. It will be appreciated that the wrist drive unit 194 and end effector wrist unit 102 may also be mounted to other types of robotic arm units, for example, robotic arms having robotic arm links that are not limited to extension and retraction in a single horizontal plane, but may instead perform more complex movements, for example, rotate about axes other than parallel vertical axes. Regardless of what type of robotic arm the wrist drive unit 194 and end effector wrist unit 102 are mounted to, the wrist drive unit 194 may be used to flip the end effector wrist unit 102 from a position in which the major surfaces of the end effector blades 112 / 114 are substantially horizontal, to an inverted position (in which the end effector blades 112 / 114 are effectively upside down or otherwise reversed in orientation).

[0052] The end effector wrist unit 102 may include a wrist unit housing 104 / 104' attached to the wrist drive unit 194 by a wrist mount 196, shown retracted from the end effector wrist unit 102 in the detailed view of Figure 1. The wrist mount 196 may be attached to the wrist unit housing 104 / 104' using one or more fasteners or other mechanical connections (not shown). The wrist mount 196 may be rotatable, for example, about a rotation axis D relative to the rest of the wrist drive unit 194.

[0053] A pair of end effector blades 112 and 114 may be connected to the end effector wrist unit 102, and although in some implementations the two end effector blades 112 and 114 may be part of a single continuous structure, in this example they are separate pieces. As will be appreciated, the end effector wrist unit 102 may be a subassembly of components that connects the end effector blades 112 and 114 to a robotic arm assembly that supports the end effector blades 112 and 114.

[0054] The end effector blades 112, 114 may be connected to an end effector mount assembly in the end effector wrist unit 102 (described in more detail below) that can pivot to some extent about an axis, for example, perpendicular to an axis that is parallel to the rotation axes A-D.

[0055] 2-1-2-3 show side views of the end effector wrist unit 102, end effector blades 112 and 114, and wafer 101 in various potential pivot positions of the end effector mount assembly (and end effector blades 112, 114 attached thereto). In FIG. 2-1, the wrist unit housing 104, 104' is shown with a rotation interface 110 visible. The rotation interface 110 may rotatably connect the end effector mount assembly housed within the end effector wrist unit 102 with the wrist unit housing 104. The end effector blades 112, 114 may extend outwardly from the wrist unit housing 104, 104' and may have, for example, a distal cleat 120 and a proximal cleat 120' that may be attached to an actuator mechanism 132 and used to grip the wafer 101 in the orientation shown. In some implementations, at least one of the distal cleats 120 may be secured to a distal end of the end effector, i.e., fixed relative to the end effector, while in some implementations, the proximal cleat 120' may be movably mounted to the actuator mechanism 132, e.g., mounted to a moveable portion of the actuator mechanism such that the proximal cleat 120' is moveable relative to a portion of the actuator mechanism that is fixed relative to the end effector mount assembly.

[0056] In FIG. 2-1, the end effector mount assembly has been rotated to a first rotation limit 146. In FIG. 2-2, the end effector mount assembly has been rotated to a second rotation limit 148. In FIG. 2-3, FIGS. 2-1 and 2-2 are shown superimposed, with FIG. 2-1 shown in dashed lines to indicate the full angular range 144 through which the end effector blades 112 and 114 may be swung through rotation of the end effector mount assembly about the rotation interface 110. As can be seen, the amount of angular rotation supported by the rotation interface 110 and other elements of the end effector wrist unit 102 may be very limited, such as on the order of 10° or less, such as 3° or less.

[0057] 3 shows an exploded view of an example end effector wrist unit 102 and attached end effector blades 112 and 114. As can be seen, the wrist unit housing 104 and 104' may house a number of components therein, including an end effector mount assembly including a first end effector mount 108, a second end effector mount 109, a bridge structure 111, and a clamping plate 113. The clamping plate 113, in conjunction with the fasteners shown, may be used to clamp the end effector blades 112, 114 in place relative to the end effector mount assembly.

[0058] The bridge structure 111 may span between the first end effector mount 108 and the second end effector mount 109, thereby causing the bridge structure 111, the first end effector mount 108, and the second end effector mount 109 to rotate together about the rotational axis of the rotational interface 110 when subjected to torque. As will be appreciated, the bridge structure 111, the first end effector mount 108, and the second end effector mount 109 may be provided by a single continuous structure or by multiple smaller structures joined together in a generally rigid assembly.

[0059] The end effector wrist unit 102, in this example, includes a damper mechanism 156, e.g., a linear damper mechanism, such as a pneumatic damper mechanism, that may be used to dampen rotational movement of the end effector mount assembly about the axis of rotation of the rotational interface 110'.

[0060] In this example, the first end effector mount 108 includes an arm portion that extends toward the rear of the wrist unit housing 104, e.g., toward where the end effector wrist unit 102 attaches to the wrist mount 196. The arm portion of the first end effector mount 108 may include mechanisms that facilitate the interference functions described above. For example, the end effector wrist unit 102 may include a rocker arm 168 and a draw link 162, which may be rotatably coupled to each other and to other components, thereby forming a linkage mechanism that may be used to convert rotational movement of the end effector mount assembly relative to the wrist unit housing 104 into linear movement that can be damped by a damper mechanism 156, as described in more detail below.

[0061] The example of FIG. 3 also includes a first positive stop 152 and a second positive stop 154. In this example, the first positive stop 152 and the second positive stop 154 ​​are both set screws that may be screwed in and out of their respective threaded holes to adjust the angular range over which the end effector mount assembly can swing or rotate. In other implementations, one or both of the first positive stop 152 and the second positive stop 154 ​​may be fixed, i.e., non-adjustable. For example, the second positive stop 154 ​​may be fixed / non-adjustable in position and the first positive stop 152 may be adjustable. The second end effector mount 109 may have an arm portion that extends into the gap that exists between the first positive stop 152 and the second positive stop 154, and by moving the first positive stop 152 and / or the second positive stop 154 ​​in and out of their respective screw holes, the gap distance between the first positive stop 152 and the second positive stop 154 ​​may be adjusted, thereby making it possible to adjust the angular range over which the second end effector mount 109 can swing.

[0062] The bridge structure 111 may be used to connect the first end effector mount 108 and the second end effector mount 109 to one another for movement together, as described above. The bridge structure may also serve to support an actuator mechanism 132, which in some examples may be used to engage or disengage the proximal cleat 120′ from the wafer 101.

[0063] The end effector blades 112 and 114 may generally be large, flat structures having a major surface 140 defining a first side, which may generally be parallel to the wafer 101 to be supported by the end effector blades 112 and 114. The end effector blades 112 and 114 may generally be of similar design, e.g., mirror images of one another. The end effector blades 112 and 114 may have, for example, a proximal end 118 and a distal end 116, respectively. The end effector blades 112 and 114 may be connected to an end effector mount assembly at the proximal end 118, for example, by clamping the end effector blades 112 and 114 between a clamping plate 113 and first and second end effector mounts 108 and 109, respectively. Distal cleats 120 may be provided at distal ends 116 of end effector blades 112 and 114 and connected to end effector blades 112 and 114 such that they are fixed to one another. End effector blades 112 and 114 may also have contact pads 126 that may be secured to end effector blades 112 and 114 near their proximal ends 118.

[0064] The actuator mechanism 132 may have a first portion 134 that may be attached to the bridge structure 111, for example, in a manner fixed in space relative to the end effector mount assembly 106, and a second portion 136 that may be movable relative to the first portion, for example, extended or retracted along an axis. The proximal cleat 120' may be attached to the second portion 136 of the actuator mechanism 132 such that the proximal cleat 120' may be moved toward or away from the distal ends 116 of the end effector blades 112 and 114.

[0065] It will be understood that in other additional or alternative implementations, the end effector blades 112 and 114 may be mounted to the end effector mount assembly 106 by an actuator mechanism or a mechanism similar to actuator mechanism 132, i.e., the end effector blades 112 and 114 may be extended or retracted along an axis parallel to an axis perpendicular to the first axis 176 by actuation of the actuator mechanism, thereby causing one or more second portions thereof (to which the end effector blades 112 and 114 may be mounted) to translate along such axis relative to one or more first portions thereof (e.g., which may be mounted to the end effector mount assembly 106 or a portion thereof). In such implementations, the clamp 113 (or other suitable device for securing the end effector blades 112 and 114 to the end effector wrist unit 102) may instead clamp the end effector blades 112 and 114 to a second portion of an actuation mechanism used to move the end effector blades 112 and 114. In such implementations, the distal cleat may be pivotable about a first axis and translatable along an axis parallel to an axis perpendicular to the first axis relative to the end effector wrist unit 102. The proximal cleat or cleats may also be translatable along such an axis if the actuator mechanism 132 is retained, or may be fixed relative to the end effector mount assembly 106 if the actuator mechanism 132 is omitted.

[0066] 4 shows the same assembly in an unexploded state from an alternative perspective (with the wrist unit housing 104' hidden from view). As can be seen in the drawing, the rotational interface 110 allows the end effector mount to rotate about a first axis 176. The rotational interface 110 is shown in this example as an axle or pin, but may be provided using any suitable rotational mechanism including, for example, a rotary flexure bearing, which may provide a small amount of rotational movement without undergoing or creating any rotating or sliding contact between mating surfaces (thereby reducing the risk of particle generation).

[0067] Also visible in Figure 4 is the arrangement of the arm portion of the second end effector mount 109 between the first positive stop 152 and the second positive stop 154, as well as the assembled linkage including the rocker arm 168 and the draw link 162. In addition to the first axis 176, Figure 4 also shows a second axis 178, a third axis 180, a fourth axis 182, and a fifth axis 184. As shown, the rocker arm 168 is configured to pivot relative to the wrist unit housing 104 about the fifth axis 184 and is rotatably connected to a first end of the damper mechanism 156 such that the rocker arm 168 can rotate relative to the damper mechanism 156 about the fourth axis 182. The draw link 162 may then be rotatably coupled to the rocker arm 168 such that it can rotate relative to the rocker arm 168 about a second axis 178, and is rotatably coupled at the other end to the first end effector mount 108 such that it can rotate relative to the first end effector mount 108 about a third axis 180.

[0068] Figure 5 shows the same view as Figure 4, but with the end effector mount assembly rotated to a second rotation limit 148. (The positions of the various components as shown in Figure 4, e.g., at the first rotation limit 146, are shown in dashed lines in Figure 5.) A linkage may be used to increase the linear travel distance experienced by the damper mechanism in response to the amount of vertical movement of the arm portion of the first end effector mount 108, thereby allowing for finer interference control.

[0069] FIG. 6 shows a cross-sectional view of the end effector wrist unit 102, showing the linkage mechanism described above in more detail. As can be seen, the end effector mount assembly 106 includes both the first end effector mount 108 and the bridge structure 111. The damper mechanism 156 (shown in outline, omitting internal details) has a first end 158 that is rotatably connected to the second end 172 of the rocker arm 168, allowing the two components to rotate relative to each other about a fourth axis 182. The damper mechanism 156 also has a second end 160 that is rotatably connected to the wrist unit housing 104 (or a point fixed in space relative thereto). In other implementations, the damper mechanism 156 may be rigidly connected to the wrist unit housing 104, and compliance built into other components of the damper mechanism 156 may be used to accommodate slight rotational movement of the first end 158. The rocker arm 168 has a first end 170 rotatably connected to the first end 164 of the draw link 162, such that the two components can rotate relative to one another about a second axis 178, and is rotatably connected to the wrist unit housing 104 using a pivot that allows the rocker arm 168 to rotate relative to the wrist unit housing 104 about a fifth axis 184.

[0070] The first end effector mount 108 may be rotatably connected at one end to the second end 166 of the draw link 162 such that the draw link 162 can rotate relative to the first end effector mount 108 about the third axis 180. When the first end effector mount 108 rotates clockwise about the first axis 176, the draw link 162 is pushed down and the rocker arm 168 also rotates clockwise. When the first end effector mount 108 rotates counterclockwise about the first axis 176, the draw link 162 is pulled up and the rocker arm 168 rotates counterclockwise. Due to the different distances between the second axis 178 and the fifth axis 184 and between the fifth axis 184 and the fourth axis 182, the rocker arm 168 may act to multiply the damping effect provided by the damper mechanism 156 to the first end effector mount 108. For example, the rocker arm may have a first distance 186 between the fourth axis 182 and the fifth axis 184 and a second distance 188 between the fifth axis 184 and the second axis 178 that is less than the first distance. In some such implementations, the first distance 186 may be at least 1.5 times the second distance 188, e.g., at least 3 times, at least 3.4 times, at least 3.8 times, or at least 4.2 times.

[0071] 6 is a portion of the first end effector blade 112, including a dashed line indicating a major surface 140 of the first end effector blade 112. In this example, the first end effector blade 112 clamps against a first flat end effector mounting surface 150 and is held in place by a clamping plate 113. The first flat end effector mounting surface 150 may be parallel to the first axis 176, for example. However, it will be understood that other mounting configurations for the first end effector blade 112 may be used as well, if appropriate.

[0072] As mentioned above, end effector blades 112 and 114 attached to end effector wrist unit 102 may be used to pick up a wafer 101 located on a pedestal. Figures 7-11 show side views of an example end effector wrist unit and end effector blade at various stages of a wafer pick operation.

[0073] In FIG. 7, an end effector wrist unit 702 is shown having a wrist unit housing 704, 704′ and a first end effector mount 708 and a first end effector blade 712 attached thereto. The first end effector mount 708 is rotatably mounted to the wrist unit housing 704, 704′ via a rotation interface 710. The first end effector blade 712 may have a distal cleat 720 attached to its distal end (as in the example of FIG. 7, there may be a second end effector blade with another distal cleat 720 attached). The distal cleat 720 may have a riser portion 722 and a catch surface 724 extending therefrom toward the wrist unit housing 704, 704′. The catch surfaces 724 may be spaced from the first end effector blade by at least a first gap distance, e.g., a distance at least greater than a thickness of the wafer 701, and may be angled such that the first gap distance increases for each catch surface 724 with distance from the respective riser portion 722, e.g., such that the catch surfaces 724 (and for that matter, catch surfaces 724', described below) all have a normal toward the end effector blade and toward approximately the center of the wafer 701 when the wafer 701 is held by the end effector. The wrist unit housing 704, 704' may also include an actuator mechanism 732 having a first portion (not shown) fixed relative to the wrist unit housing 704, 704' and a second portion 736 that is movable relative to the first portion. The second portion 736 of the actuator mechanism 732 may have a proximal cleat 720' with the catch surface 724' extending outwardly from the riser portion 722' toward the distal cleat 720. When the actuator mechanism 732 is actuated, the second portion 736 thereof, along with the proximal cleat 720', extends towards or retracts from the distal cleat 720.The use of angled catch surfaces 724 and 724' may be employed to ensure that the wafer does not contact cleats 720 and 720' except along the outer diameter and / or outer edge, i.e., cleats 720 and 720' do not contact the underside of the wafer except along the bottom edge.

[0074] 7, a first end effector blade 712 is positioned above a wafer 701 housed on a pedestal 703, which may be in, for example, a semiconductor processing chamber. The pedestal 703 may provide one or more recesses around the circumference of the wafer 701 over which the wafer 701 may overhang.

[0075] During a wafer pick operation, the end effector wrist unit 702 may be lowered toward the pedestal 703 and wafer 701. The first end effector blade 712 may rotate downward due to gravity until it reaches the limit of the angular range within which it is configured to be able to rotate.

[0076] In Figure 8, the end effector wrist unit 702 has been lowered further until the distal cleat 720 comes into contact with the base 703. In Figure 9, the end effector wrist unit 702 continues to move downwardly relative to the base 703 until the proximal cleat 720' is at a height that aligns with the wafer 701, e.g., until the catch surface 724' is below, or at least partially below, the bottom edge of the wafer 701. It will be appreciated that the distal and proximal cleats 720 and 720' are positioned in this configuration such that their contact surfaces 724 and 724' can all be completely outside of a circle having a diameter of the wafer 701.

[0077] In FIG. 10 , actuator mechanism 732 may be actuated to move proximal cleat 720′ toward distal cleat 720, thereby causing catch surface 724′ to fall past the bottom edge of wafer 701. At the same time, end effector wrist unit 702 may be caused to move a smaller amount in the opposite direction, such that distal cleat 720 is also caused to move toward proximal cleat 720′, thereby causing catch surface 724 to also fall past the bottom edge of wafer 701. Such movement of distal cleat 720 and proximal cleat 720′ may continue, for example, until wafer 701 is no longer able to shift and clear catch surfaces 724 and 724′ and riser portions 722 and 722′. In such a configuration, catch surfaces 724 and 724′ may all overlap a circle that is of the same diameter as wafer 701. Such a circle, sometimes referred to herein as a reference circle, may have the same diameter as the wafer 701 to be handled by the end effector, for example 200 mm, 300 mm, 450 mm, etc.

[0078] Once the wafer 701 is securely trapped by the catch surfaces 724 and 724' and the riser portions 722 and 722', the end effector wrist unit 702 may be moved upward to lift the wafer 701 supported by the catch surfaces 724 and 724' from the pedestal 703.

[0079] If the end effector wrist unit 702 is then rotated 180 degrees, e.g., upside down, the wafer 701 may rest on the surface of the distal cleat 720 facing the catch surface 724 and on the contact pad 726. This allows the wafer 701 to be turned upside down during wafer pick and place operations.

[0080] Once the wafer 701 is suspended beneath the end effector blade 712, i.e., resting on the catch surface 724, the end effector wrist unit 702 may, in some implementations, be used to place the wafer on a pedestal (or another structure). For example, the end effector wrist unit 702 may first be positioned so that the end effector blade 712 is approximately parallel to the surface that will ultimately receive the wafer 701, and then may be lowered until the wafer contacts that surface. Once the end effector wrist unit 702 has been lowered to place the wafer in contact with the receiving surface, the actuator mechanism 732 may be actuated to retract the proximal cleat 720' away from the wafer 701, thereby releasing one edge of the wafer 701. The end effector wrist unit 702 may then be simultaneously moved upwards towards the wafer 701 such that the end effector wrist unit 702 follows an inclined path, for example 20°-40° from horizontal, for example 30° from horizontal. Such movement allows the proximal cleat 720′ (assuming it is fully retracted) to move away from the wafer edge while allowing the catch surface of the distal cleat 720 to move out from underneath the wafer 701. The end effector wrist unit 702 may then be moved vertically upwards as the cleats 720 and 720′ move away from the wafer 701. A similar process, but with the vertical movement in the opposite direction, may be performed to position the wafer 701 in a position where the end effector wrist unit 702 would have been rotated 180°, i.e., where the wafer 701 is above the end effector blade 712.

[0081] Alternatively, the same process described above with respect to Figures 7-11 may be generally performed in reverse to perform a wafer placement operation (in either orientation of the end effector wrist unit 702).

[0082] It will be appreciated that the end effector wrist units discussed herein provide only very limited rotational movement of the end effector mount assembly and the attached end effector blade relative to the wrist unit housing, and that such movement may be passive in nature, e.g., not controlled using motors, actuators, or spring mechanisms. For example, if a rotary flexure bearing is used by the end effector wrist unit rotation interface, the torque developed by flexure of such a flexure bearing may be insufficient to prevent the end effector mount assembly and the attached end effector blade from rotating through the angular range of motion defined by the first and second rotation limits due to the gravitational load of the end effector mount assembly and the end effector blade when the end effector wrist unit is oriented such that the major surface of the end effector blade is approximately horizontal (subject to a slight tilt that may be developed at the first or second rotation limits) or turned upside down from such orientation. Thus, an end effector blade mounted on a wrist unit for such an end effector may have a small amount of compliance at its disposal that allows it to engage the pedestal during a wafer pick operation, as shown in Figures 7-11. A damper mechanism may optionally be used to limit the speed at which the end effector mount assembly rotates relative to the wrist unit housing, and to cushion any shock or vibration that may occur as a result of such rotational movement.

[0083] It will also be appreciated that the wrist units for end effectors discussed herein may be used not only to pick and place wafers from horizontal positions, but also to pick and place wafers from wafer positions that are not horizontal, for example at an angle of up to 60° from the horizontal, where the wafer may be placed on or picked up from a wafer support surface.

[0084] Phrases such as "with respect to each 'item' of one or more 'items'" and "with respect to each 'item' of one or more 'items'" as used herein should be understood to include both single and multiple item groups, i.e., the phrase "with respect to each" is used in the sense that it is used in programming languages ​​to refer to each of the items referenced, regardless of what the population of items is. For example, if the population of items referenced is a single item, then "each" refers only to that single item (notwithstanding the fact that dictionary definitions of "each" often define terms to refer to "one each of two or more things") and does not imply that there must be at least two of the items. Similarly, the terms "set" or "subset," by themselves, should not be considered to necessarily encompass a plurality of items, and it will be understood that a set or subset may (unless the context dictates otherwise) encompass only one member or multiple members.

[0085] Terms such as "approximately," "about," "substantially," "nominal," and the like, when used in reference to a quantity or similar quantifiable property, unless otherwise indicated, should be understood to include values ​​within ±10% of the specified value or relationship (as well as to include the actual value or relationship specified).

[0086] It is understood that the examples and embodiments described herein are for illustrative purposes only, and various modifications or changes in light thereof will be presented to those skilled in the art. Various details have been omitted for clarity, and various design alternatives may be realized. Therefore, the examples of the present invention should be considered as illustrative rather than restrictive, and the disclosure should not be limited to the details provided herein, but may be modified within the scope of the disclosure.

[0087] While the above disclosure focuses on one or more particular example implementations, it should be understood that the disclosure is not limited to only the discussed examples, but may also apply to similar modifications and mechanisms, and such similar modifications and mechanisms are also considered to be within the scope of the disclosure.

Claims

1. An apparatus comprising: Equipped with a wrist unit for end effector, The end effector wrist unit includes: A wrist unit housing; an end effector mount assembly having a first end effector mount; one or more rotation interfaces; the first end effector mount is configured to mechanically couple to a first end effector blade having a major surface defining a first face; the end effector mount assembly is connected to the wrist unit housing via the one or more rotational interfaces such that the end effector mount assembly is rotatable about a first axis through a first angular range of motion relative to the wrist unit housing; the first axis is substantially parallel to the first plane when the first end effector blade is mounted to the first end effector mount. Device.

2. 2. The apparatus of claim 1, the first end effector mount having a first planar end effector mounting surface configured to mate with the first end effector blade when the first planar end effector mounting surface is parallel to the first axis.

3. The apparatus of claim 1 , further comprising the first end effector blade.

4. The apparatus of claim 3, wherein the first end effector blade is made from a ceramic material.

5. The apparatus of claim 3, wherein the first end effector blade is made of silicon carbide.

6. 2. The apparatus of claim 1, Further comprising a first positive stop and a second positive stop; the first positive stop is positioned to contact a portion of the end effector mount assembly when the end effector mount assembly is at a first rotational limit of the first angular range of motion, and the second positive stop is positioned to contact a portion of the end effector mount assembly when the end effector mount assembly is at a second rotational limit of the first angular range of motion.

7. The apparatus of claim 6 , wherein one or both of the first positive stop and the second positive stop are adjustable.

8. The apparatus of claim 1 , wherein the first angular range of motion is less than 10 degrees.

9. 2. The apparatus of claim 1, The apparatus further comprising a damper mechanism configured to dampen rotational movement of the end effector mount assembly relative to the wrist unit housing.

10. 10. The apparatus of claim 9, Further comprising a draw link and a rocker arm, the draw link has a first end rotatably coupled to the first end of the rocker arm such that the draw link can rotate relative to the rocker arm about a second axis, and a second end rotatably coupled to the end effector mount assembly such that the draw link can rotate relative to the end effector mount assembly about a third axis, the rocker arm has a second end rotatably coupled to a first end of the damper mechanism such that the rocker arm is rotatable relative to the damper mechanism about a fourth axis, and the rocker arm is mounted such that the rocker arm is rotatable about a fifth axis fixed relative to the wrist unit housing.

11. 11. The apparatus of claim 10, A first distance between the fifth axis and the fourth axis is greater than a second distance between the fifth axis and the second axis.

12. The apparatus of claim 11 , wherein the first distance is at least 1.5 times the second distance.

13. The apparatus of claim 3 , further comprising a second end effector blade fixed relative to the end effector mount assembly.

14. 14. The apparatus of claim 13, the first and second end effector blades each having a corresponding distal end and a corresponding proximal end; the proximal ends of the first and second end effector blades are fixedly attached to the end effector mount assembly; a distal cleat is attached to the distal end of each of the first and second end effector blades; each distal cleat having a riser portion extending away from a corresponding end effector blade and a catch surface extending outwardly from each of the riser portions; Each catch surface is spaced from the corresponding end effector blade by at least a first gap distance.

15. The apparatus of claim 14 , wherein each catch surface slopes away from the corresponding end effector blade with increasing distance from the riser portion from which the catch surface extends.

16. 16. The apparatus of claim 15, further comprising an actuator mechanism and a proximal cleat; the actuator mechanism having a first portion and a second portion; the first portion of the actuator mechanism is fixed relative to the end effector mount assembly; the second portion of the actuator mechanism is configured to be movable relative to the first portion of the actuator mechanism between a first configuration and a second configuration; the proximal cleat is fixed relative to the second portion of the actuator mechanism and has a catch surface facing substantially the same direction as the catch surface of the distal cleat; the catch surface of the proximal cleat and the catch surface of the distal cleat do not overlap a first reference circle when the second portion of the actuator mechanism is in the first configuration; the catch surface of the proximal cleat and the catch surface of the distal cleat, in the second configuration, all overlap a second reference circle when the second portion of the actuator mechanism is in the second configuration; The first reference circle and the second reference circle have the same diameter.

17. 17. The apparatus of claim 16, wherein the first reference circle has a diameter selected from the group consisting of 200 mm, 300 mm, and 450 mm.

18. 2. The apparatus of claim 1, The end effector wrist unit includes: when the end effector wrist unit is positioned in a first orientation with the first axis horizontal and the first plane substantially horizontal, the end effector mount assembly moves under gravity load alone to a first rotational limit of the first angular range of motion; When the end effector wrist unit is positioned in a second orientation opposite the first orientation, the end effector mount assembly moves to a second rotational limit of the first angular range of motion under gravitational loads alone. An apparatus configured as follows.

19. 2. The apparatus of claim 1, a base, one or more robotic arm links, and a wrist drive unit; the one or more robot arm links include a first robot arm link configured to be rotatable about a base axis relative to the base; the wrist drive unit includes a wrist mount supported by the one or more robot arm links and rotatable about an axis perpendicular to an axis parallel to the base axis; The apparatus wherein the end effector wrist unit is mounted to the wrist mount.

20. 2. The apparatus of claim 1, a base, one or more robotic arm links, and a wrist drive unit; The one or more robot arm links include a first robot arm link configured to be rotatable relative to the base; the wrist drive unit includes a wrist mount supported by the one or more robot arm links and rotatable about an axis perpendicular to the first axis; The end effector wrist unit is mounted to the wrist mount.

21. 1. A method comprising: a) moving an end effector wrist unit to a first position relative to a wafer mounted on a pedestal, the end effector wrist unit supporting one or more end effector blades rotatably mounted relative to the end effector wrist unit using one or more rotation interfaces; the one or more end effector blades are rotatable relative to the end effector wrist unit about a first axis; the one or more end effector blades having a distal cleat attached to one or more distal ends thereof; Moving an end effector wrist unit; b) lowering the end effector wrist unit from the first position to a second position where the distal cleat first contacts the base; c) further lowering the end effector wrist unit from the second position to a third position thereby rotating the one or more end effector blades relative to the end effector wrist unit about the first axis; A method comprising:

22. 22. The method of claim 21, and when in the third position, a proximal cleat supported by the end effector wrist unit is positioned such that a catch surface is located such that at least a portion of the catch surface is at a lower height relative to a normal vector of the wafer than an edge of the wafer.

23. 23. The method of claim 22, the method further comprising moving at least one of the distal cleat and the proximal cleat radially inward relative to the wafer so that the catch surface of the proximal cleat and the catch surface of the distal cleat all overlap the wafer when viewed along an axis perpendicular to the wafer.

24. 24. The method of claim 23, the method further comprising, after moving the at least one of the distal and proximal cleats radially inward relative to the wafer, raising the end effector wrist unit a fourth distance to lift the wafer off the pedestal.

25. 25. The method of claim 24, after raising the end effector wrist unit the fourth distance, rotating the end effector wrist unit 180 degrees about a second axis perpendicular to the first axis and substantially parallel to the wafer.

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