Method and Holder Assembly for Rotating a Cleanroom Container

Abstract

The present invention discloses a gripper assembly for gripping a cleanroom container, comprising: a gripper adapted to grip a cleanroom container; a lifting unit including a first motor for lifting the gripper; at least one cable connecting the gripper to the lifting unit, the at least one cable being driven by the first motor; a second motor for rotating at least a part of the gripper relative to the lifting unit about a vertical axis; the gripper includes engaging elements, and the lifting unit includes complementary engaging elements, the complementary engaging elements being adapted to engage with the engaging elements to prevent the gripper from rotating relative to the lifting unit about the vertical axis; the gripper includes an upper gripper element and a lower gripper element; the lower gripper element is adapted to support the top flange of the cleanroom container; the lower gripper element includes an opening passing through the upper flange of the cleanroom container, and at least one notch formed at least partially around the opening.

Description

Technical Field

[0001] The present invention relates to a method and a gripper for rotating a cleanroom container such as a Front Opening Unified Pod (FOUP) or a Front Open Shipping Box (FOSB) or a reticle pod. Background Art

[0002] FOUP is an abbreviation for Front Opening Unified Pod or Front Opening Universal Pod. Such a FOUP is used to transport wafers in a wafer fab. Semiconductor wafers are placed horizontally and vertically stacked in the FOUP. The FOUP is well known to those skilled in the art and thus need not be described in further detail herein.

[0003] In a wafer fab for manufacturing semiconductor circuits, the FOUP may need to be transported manually. To maintain the cleanroom state, it is preferably to automatically transport the FOUP by a suitable transport system. Such a transport system may be equipped with an overhead track and a lifting system thereon to assist in lifting the FOUP. The lifting system may include a motor that drives a plurality of buckets around which cables connected to an actual gripper are wound. The gripper can grip the FOUP for lifting and can release the FOUP after the FOUP is lowered to a proper position.

[0004] FOSB is a Front Open Shipping Box, which is used to transport wafers from a wafer fab to other locations outside the cleanroom. A reticle pod can accommodate at least one reticle.

[0005] However, the prior art lifting system cannot rotate a cleanroom container. Summary of the Invention

[0006] The present invention is to provide a method and a gripper assembly capable of rotating a cleanroom container.

[0007] The present invention can be achieved by a gripper assembly and its use method.

[0008] The present invention discloses a use method of a gripper assembly for rotating a cleanroom container, including the following steps: lowering the gripper to the cleanroom container, wherein the gripper is connected to at least one cable. The method further includes the step of gripping the cleanroom container by the gripper. The cleanroom container is lifted to a lifting unit through the at least one cable and a first motor, wherein the at least one cable is connected to the lifting unit. The gripper engages the lifting unit with a complementary engaging element of the lifting unit through an engaging element of the gripper. Then, the cleanroom container held by the gripper is rotated.

[0009] In one embodiment, the gripper may include an upper gripper element and a lower gripper element, wherein the lower gripper element rotates relative to the upper gripper element.

[0010] In another embodiment, the lifting unit may include two elements, wherein a lower lifting unit element rotates relative to an upper lifting unit element.

[0011] Since the gripper is engaged with the lifting unit, which is connected to an overhead transport system, an overhead rack, etc., torque can be transmitted from the gripper to the lifting device and from the lifting device to the device to which the lifting device is attached, such as an overhead rack or an overhead rail system. The torque cannot be transmitted on the plurality of cables connecting the lifting unit and the gripper to raise and lower the gripper and the cleanroom container.

[0012] An advantage of the present invention is that the cleanroom container can be rotated, and the cleanroom container does not need to be rotated manually or by an individual rotating device connected to a semiconductor manufacturing equipment or a cleanroom container storage equipment, etc.

[0013] The cleanroom container can be a FOUP, a FOSB, or a reticle pod. These devices are well known to those skilled in the art and thus will not be described in further detail herein.

[0014] The method further includes the step of engaging the gripper with the lifting unit, wherein the gripper does not grip the cleanroom container before the step of lowering the gripper. After that, at least a part of the gripper is rotated. The part of the gripper that rotates can be the part that actually grips the cleanroom container. These steps can ensure that the gripper is positioned in the correct position for gripping the cleanroom container.

[0015] The step of rotating the cleanroom container held by the gripper can be performed during the process of moving the lifting unit and the gripper in the horizontal direction. Thus, the position and orientation of the cleanroom container can be changed simultaneously.

[0016] In one embodiment, in the step of lowering the gripper, the opening in the lower gripper element passes through the top flange of the cleanroom container. The lower gripper element rotates relative to the upper gripper element of the gripper. The gripper is lifted until the top flange is received in the notch in the lower gripper element. The cleanroom container with the top flange can be gripped by the gripper without any clamping device, etc. The notch for receiving the top flange can have a different orientation compared to the opening in the lower gripper element. The dimensions of the FOUP and the dimensions of the top flange are defined in SEMI E47.1-1106.

[0017] In one embodiment, the method may include the following steps. In the step of lowering the gripper, a centering element coupled to the upper gripper part is inserted into an opening in the top flange of the cleanroom container. The centering element may be movable, for example, movable in the vertical direction. The method determines whether the centering element moves a predetermined distance relative to the upper gripper element. Once the centering element contacts the opening in the top flange and the gripper continues to be lowered, the centering element does not move significantly relative to the world coordinate system, but moves relative to the gripper in a direction opposite to the lowering direction of the gripper. If the centering element has moved the predetermined distance relative to the gripper, the lower gripper element rotates relative to the upper gripper element of the gripper.

[0018] The lower gripper element rotates relative to the upper gripper element of the gripper until a notch formed in the upper part of the lower gripper element is aligned with the upper flange of the cleanroom container. Then, the gripper is lifted to receive the top flange of the cleanroom container in the notch formed in the upper part of the lower gripper element. Thereby, clamping devices and other moving parts can be avoided. Thus, the expected life and reliability of the gripper are increased.

[0019] After the cleanroom container is gripped by the gripper, the cleanroom container is pulled in the direction of the lifting unit.

[0020] The present invention also discloses a gripper assembly for gripping a cleanroom container. The gripper assembly includes a gripper and a lifting unit. At least one cable is connected to the gripper and the lifting unit. The gripper includes a mating element, and the lifting unit includes a complementary mating element, and these complementary mating elements are adapted to mate with these mating elements to prevent the gripper from rotating relative to the lifting unit. The gripper assembly may include a first motor for rotating at least a part of the gripper relative to the lifting unit.

[0021] Since the gripper is engaged with the lifting unit, the torque generated by rotating the cleanroom container gripped by the gripper can be transmitted from the gripper to the lifting unit and to any device mounted on the lifting unit, such as an overhead rail system, an overhead rack, etc.

[0022] In one embodiment, the gripper may be formed in two parts, and the first motor may cause one of the gripper parts arranged horizontally one above the other to rotate about a vertical axis relative to the other gripper part.

[0023] In another embodiment, the gripper may be formed in two parts, and the first motor may cause one of the lifting unit parts arranged horizontally one above the other to rotate about a vertical axis relative to the other part of the lifting unit.

[0024] The cleanroom container can be a FOUP, a FOSB, or a reticle container. These devices are well known to those skilled in the art and thus need not be described in further detail herein.

[0025] In one embodiment, the gripper includes an upper gripper element and a lower gripper element. The lower gripper element is adapted to support the top flange of the cleanroom container. The lower gripper element includes an opening that can pass through the upper flange of the cleanroom container, and at least one notch formed at least partially around the opening for receiving the upper flange of the cleanroom container. The notch can be formed in the upper portion of the lower gripper element. The at least one notch can be formed to correspond to the shape of the top flange of the cleanroom container. A plurality of notches can be arranged partially around the opening. The at least one notch can be interpreted as having a notch with a shape complementary to the lower portion of the top flange of the cleanroom container, where the notch is interrupted by the opening.

[0026] In one embodiment, the opening in the lower gripper element is substantially rectangular. Each of the plurality of notches individually includes a generally triangular shape. Each notch having a generally triangular shape is symmetrically arranged with respect to the axis of symmetry of the opening and is arranged at the edge of the opening. The triangle can be symmetric, where the hypotenuse is arranged at the opening, and the two straight sides form a 45° angle with respect to the hypotenuse. The rectangular opening and / or the generally triangular notches can include rounded edges.

[0027] The gripper is lowered until the opening in the lower gripper element passes through the lower portion of the top flange of the cleanroom container. Then, the lower gripper element is rotated 45°, and the gripper is lifted again. Thereby, the lower portion of the top flange of the cleanroom container is received by these notches.

[0028] The gripper can include a centering element movably attached to the upper gripper element, and a motion sensor can detect the movement of the centering element. The motion sensor can be an optical sensor, such as a photoelectric fence. When the gripper descends to the cleanroom container, the centering element is inserted into the opening of the top flange of the cleanroom container. The gripper continues to lower. Thereby, the centering element can determine the position of the lower gripper element relative to the bottom of the top flange.

[0029] Once the controller determines that the lower gripper element has passed the bottom of the top flange through the movement of the centering element relative to the upper gripper element, the controller instructs the first motor to stop lowering the gripper and instructs the second motor to rotate the lower gripper element relative to the upper gripper element, for example, 45°. After that, the controller instructs the first motor to lift the gripper. Thereby, the lower portion of the top flange of the cleanroom container is received by at least one notch formed in the upper portion of the lower gripper element.

[0030] The lifting unit includes a first motor that is connected to at least one bucket for winding at least one cable.

[0031] In one embodiment, the clamping arrangement is coupled to the controller, where the controller is adapted to perform the steps of the foregoing method. The controller can be part of the lifting unit or part of the cleanroom container transportation system or the like. Brief Description of the Drawings

[0032] Figure 1 Showing a cross-sectional sketch of a gripper assembly for gripping a FOUP;

[0033] Figure 2 Showing a perspective view of the lower gripper element.

[0034] Description of the Reference Numerals

[0035] 100: Gripper assembly

[0036] 102: Driving post

[0037] 200: Lifting unit

[0038] 202: Housing

[0039] 208: Cable

[0040] 204: First motor

[0041] 206: Bucket

[0042] 208: Cable

[0043] 210: Controller

[0044] 212: Light source

[0045] 214: Photoelectric detector

[0046] 216: Pin

[0047] 300: Gripper

[0048] 302: Upper gripper element

[0049] 304: Second motor

[0050] 306: Pinion

[0051] 312: Light source

[0052] 314: Photoelectric detector

[0053] 316: Inner cone

[0054] 318: Centering element

[0055] 320: Guide element

[0056] 322: Lower gripper element

[0057] 324: Flange

[0058] 326: Flange

[0059] 328: Notch

[0060] 330: Tapered portion

[0061] 332: Opening

[0062] 400: FOUP

[0063] 402: Top flange

[0064] 404: Support post. Detailed description of the preferred embodiment

[0065] The present invention will now be described in further detail with reference to the accompanying drawings of the specification. However, these drawings are not drawn to scale. For the purpose of describing and explaining the present invention, geometric relationships such as up, down, etc. are used herein, but should not be considered restrictive. The present invention is exemplarily described with respect to a FOUP. However, the present invention can also be applied to a FOSB or a reticle pod having a top flange.

[0066] FOUP (Front Opening Unified Pot) is an abbreviation for Front Opening Unified Pod or Front Opening Universal Pod. A FOUP is used in a semiconductor manufacturing fab to transport wafers. Multiple wafers can be arranged stacked on top of each other inside the FOUP.

[0067] Figure 1 A cross-sectional side view of a gripper assembly 100 according to the present invention is shown. The gripper assembly 100 according to the present invention is combined with a drive post 102 and mainly includes a lifting unit 200 and a gripper 300 connected by a cable 208. At least one first motor 204 drives a barrel 206 around which the cable 208 is wound. The cable 208 can support the gripper 300 and also transmit power and information.

[0068] The gripper 300 can be lowered and lifted by the rotation of the at least one first motor 204. If the at least one first motor 204 lifts the gripper 300 to an upper position juxtaposed with the lifting unit 200, the pin 216 is movably supported on the gripper 300. The housing 202 of the lifting unit 200 engages an inner cone 316 formed on the gripper 300, particularly at the top of the housing of the gripper 300. By engaging the pin 216 within the inner cone 316, the degree of freedom of rotation about the vertical axis can be reduced, i.e., invalidated, because the lifting unit 200 includes a plurality of pins 216 (not shown), which engage within respective inner cones 316 (not shown) of a plurality of inner cones 316 formed at the top of the housing of the gripper 300. The pin 216 moves in the vertical direction through the inner cone 316 until it passes through the light source 212 and the photodetector 214, where at least the photodetector 214 is connected to a controller 210. If the pin 216 passes through the light source 212 and the photodetector 214, the controller 210 detects that the pin 216 has engaged within the inner cone 316. Once all the pins 216 have engaged within the respective inner cones 316, the rotation of the FOUP 400 can be connected to the gripper 300.

[0069] The FOUP 400 includes a flange 402 supported by a strut 404.

[0070] The gripper includes an upper gripper element 302 and a lower gripper element 322, where an inner cone 316 is provided in the upper gripper element 302, and the lower gripper element 322 includes a notch 328, and a lower portion of the flange 402 of the FOUP 400 is disposed therein.

[0071] A second motor 304 attached to the upper gripper element 302 drives the lower gripper element 322 to rotate about the vertical axis through a pinion 306 by meshing with a rack formed within the flanges 324, 326.

[0072] An alignment element 318 is coupled to the upper gripper element 302 and is guided within a guiding element 320. The alignment element 318 includes a tapered portion 330, which is adapted to be introduced into an opening 332 within the top flange 402 of the FOUP 400. If the gripper 300 is lowered by the first motor 204 and the alignment element 318 engages the opening 332 in the FOUP 400 flange 402, the alignment element 318 moves relative to the upper gripper element 302 until it passes through the light source 312 and the photodetector 314.

[0073] Now referring to Figure 2To further elaborate on the lower gripper element 322 and the procedure for picking up and rotating the FOUP 400.

[0074] The lower gripper element 322 includes a generally square opening 332 with rounded edges. The opening 332 is at least slightly larger than the top flange 402 of the FOUP 400. The lower gripper element 322 is lowered by the lifting unit 200 to pick up the FOUP 400. The controller controls the second motor 304 such that the opening 332 is aligned with the top flange 402 of the FOUP 400.

[0075] The gripper 300 is lowered until the opening 332 within the lower gripper element 322 passes through the top flange 402 of the FOUP 400. During the lowering of the gripper 300, the centering element 318 engages the opening 332 in the top flange 402 of the FOUP 400 and causes the centering element 318 to move towards the light source 312 and the photodetector 314 relative to the upper gripper element 302. Once the controller 210 detects that the centering element 318 blocks the light emitted from the light source 312 to the photodetector 314, the controller 210 assumes that the lower gripper element 322 has passed through the top flange 402 of the FOUP 400.

[0076] After this, the controller 210 instructs the second motor 304 to rotate the lower gripper element 322 by 45° about a vertical axis. Thus, the notch 328 formed in the lower gripper element 322 aligns with the top flange 402 of the FOUP 400. Four notches 328 are formed along the contour of the opening 332, where each triangular notch 328 is symmetrically disposed with respect to the symmetry axis of the opening, and they are perpendicular to the edges (not corners) of the opening 332. The hypotenuse of the notch 328 is adjacent to the respective edge of the opening 332. And each straight side of the notch 328 includes a 45° angle with respect to the hypotenuse. In other words, these four notches 328 can be interpreted as notches corresponding to the dimensions of the top flange 402 of the FOUP, where the notch is rotated 45° with respect to the opening 332, and where the opening 332 makes the notch 328 discontinuous.

[0077] Once the notch 328 is aligned with the top flange 402 of the FOUP 400, the controller 210 instructs the at least one first motor 204 to lift the gripper 300 until each pin 216 engages within the inner cone 316. Then the second motor 304 is instructed to rotate the lower gripper element 322 until the FOUP 400 has the desired orientation.

[0078] The advantages of the present invention are that it can rotate the gripper 300 supported only by a cable, and the torque for rotating the FOUP 400 can be guided to the support element 100 for supporting the lifting unit 200 through an overhead rail system (not shown), an overhead (not shown), etc.

[0079] In addition, the advantages of the present invention are that the top flange 402 of the FOUP can be gripped without using a mechanical clamp, thereby reducing wear and extending the service life of the gripper 300.

[0080] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

Claims

1. A method for rotating a cleanroom container, characterized in that, comprising the following steps: Lower a gripper to a cleanroom container, wherein the gripper is connected to at least one cable; The gripper grips the cleanroom container; The at least one cable lifts the cleanroom container to a lifting unit, wherein the at least one cable is also connected to the lifting unit; Engage a mating element of the gripper with a complementary mating element of the lifting unit so as to engage the gripper with the lifting unit; The gripper causes the gripped cleanroom container to rotate about a vertical axis; In the step of lowering the gripper, insert a centering element coupled to an upper gripper portion of the gripper into an opening in a top flange of a wafer transfer cassette; Determine whether the centering element has moved a predetermined distance relative to the gripper; and If the centering element has moved the predetermined distance relative to the gripper, rotate a lower gripper element about a vertical axis relative to an upper gripper element of the gripper.

2. The method for rotating a cleanroom container according to claim 1, characterized in that, The cleanroom container is any one of the following: A wafer transfer cassette; A wafer shipping cassette; A reticle container.

3. The method for rotating a cleanroom container according to claim 1, characterized in that, Before the step of lowering the gripper, further comprising the following steps: Cause the gripper to engage with the lifting unit, wherein the gripper does not grip a cleanroom container; and Rotate at least a portion of the gripper.

4. The method for rotating a cleanroom container according to claim 1, characterized in that, During the process of the gripper and the lifting unit moving horizontally, perform the step of rotating the cleanroom container gripped by the gripper.

5. The method for rotating a cleanroom container according to claim 1, characterized in that, Further comprising the following steps: In the step of lowering the gripper, an opening in a lower gripper element of the gripper passes through a top flange of the cleanroom container; Rotate the lower gripper element relative to an upper gripper element of the gripper; and Lift the gripper until the top flange is received in a notch within the lower gripper element.

6. The method for rotating a cleanroom container according to claim 1, characterized in that, The step of rotating the lower gripper element relative to the upper gripper element of the gripper comprises the following steps: The lower gripper element rotates relative to the upper gripper element of the gripper until a notch on an upper portion of the lower gripper element is aligned with an upper flange of the cleanroom container.

7. A gripper assembly adapted to grip a cleanroom container, characterized in that, comprising: A gripper adapted to grip a cleanroom container; A lifting unit including a first motor for lifting and lowering the gripper; At least one cable connecting the gripper to the lifting unit, wherein the at least one cable is driven by the first motor; A second motor for driving at least a portion of the gripper to rotate about a vertical axis relative to the lifting unit; Wherein, the gripper includes an engaging element, and the lifting unit includes a complementary engaging element adapted to engage with the engaging element to prevent the gripper from rotating about a vertical axis relative to the lifting unit; Wherein, the gripper includes an upper gripper element and a lower gripper element; The lower gripper element is adapted to support the top flange of the cleanroom container; and The lower gripper element includes an opening capable of passing through the upper flange of the cleanroom container, and At least one notch formed partially around the opening for receiving the upper flange of the cleanroom container; Wherein the gripper includes a centering element movably attached to the upper gripper element, and a motion sensor capable of detecting the motion of the centering element.

8. The gripper assembly according to claim 7, wherein, The cleanroom container is any one of the following: A wafer transfer cassette; A wafer shipping cassette; A reticle container.

9. The gripper assembly according to claim 7, characterized in that: The opening in the lower gripper element is rectangular; and A plurality of notches having a triangular shape are symmetrically arranged with respect to the axis of symmetry intersecting the edge of the opening, and each notch is arranged at the edge of the opening.

10. The gripper assembly according to claim 9, wherein, The hypotenuse of each notch is arranged at the opening, and each straight side forms a 45° angle with the hypotenuse; or, The rectangular opening and / or the triangular notch includes a rounded edge.

11. The gripper assembly according to claim 7, wherein, The lifting unit includes a first motor connected to at least one barrel adapted to wind at least one cable.

12. The gripper assembly according to claim 7, wherein, The gripper assembly is coupled to a controller that performs the following steps: Lower a gripper to a cleanroom container, wherein the gripper is connected to at least one cable; The gripper grips the cleanroom container; The at least one cable lifts the cleanroom container to a lifting unit, wherein the at least one cable is also connected to the lifting unit; Engage the engaging element of the gripper with the complementary engaging element of the lifting unit to engage the gripper with the lifting unit; and The gripper rotates the gripped cleanroom container about a vertical axis.

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