FIELD OF THE INVENTION
The present invention relates to a multi-directional gripping apparatus, and more particularly, to a gripping apparatus capable of performing material-fetching and positioning tasks simultaneously during a manufacturing process that it is specifically adapted for manufacturing industries having to perform a fetch-to-process operation in a repetitive manner, such as wafer fabrication industry, for shortening processing time and thus increasing throughput.
BACKGROUND OF THE INVENTION
As different products are required to be processed by different manufacturing processes with reference to their own distinctive characters, not every product can be fabricated using a manufacturing process with a serial of processing procedures to be performed sequentially and continuously. Some process for manufacturing a certain products, such as wafer fabrication, is a procedure comprised of many repeated fetch-to-process operations, which primarily comprises steps listed as following:
- (a) using a grabber, such as a robotic arm, to fetch a wafer-to-be-processed out of a storage magazine;
- (b) placing the fetched wafer on a working platform for perform a process thereon;
- (c) using the grabber to pick up the wafer from the working platform after the process is accomplished;
- (d) taking the processed wafer back to the storage magazine for storage;
- (e) using the grabber to fetch another wafer-to-be-processed out of the storage magazine to be processed by the working platform.
From the above description, it is noted that the fetch-to-process operation is repeatedly being performed in a wafer fabrication process. Moreover, as there can be a plurality of working platforms for performing different processes on a fetched wafer, an operation of wafer positioning is sometimes required to be performed before a fetched wafer can be sent to process by those working platforms.
Although the abovementioned steps of the fetch-to-process operation seems to be carried out in a continuous manner, it is actually not and that can be a serious flaw for a manufacturing process. That is, when the wafer is being processed by the working platform, the grabber is held at a waiting status without any action, and when the grabber is busy fetching and positioning a wafer for placing the same on a working platform, or is busying picking up the wafer for sending the same back to the storage magazine, the working platform is idle. Thus, the idle of the working platform and the holding of the grabber can adversely prolong the processing time. However, most conventional methods for improving a manufacturing process are only focused themselves to the acceleration of the fetching/placing movements of the grabber, or to expedite the operation speed of the working platform, that are not able to improve the production yield effectively.
Therefore, it is in need of a gripping apparatus capable of making the best use of a specific processing time while performing in maximum efficiency so that it can help to shorten a manufacturing process and thus improve production yield. Relating apparatuses can be seen in U.S. Pat. No. 5,151,008 (incorporated herein by reference in its entirety), entitled “Substrate Transfer Apparatus”, U.S. Pat. No. 5,885,052 (incorporated herein by reference in its entirety), entitled “Transferring Apparatus and Robot Arm”, and TW. Pat. No. 86117663 (incorporated herein by reference in its entirety). It is noted that the transferring apparatus disclosed in TW. Pat. No. 86117663 is also the one patented in U.S. Pat. No. 6,068,704 (incorporated herein by reference in its entirety), that both had claimed priority to JP 8-330316 (incorporated herein by reference in its entirety).
Please refer to FIG. 9A to FIG. 9B, which are respectively a plan view showing a transfer arm apparatus disclosed in U.S. Pat. No. 6,068,704, and a cross-sectional view taken along line II-II in FIG. 9A. The transfer arm apparatus 30 is comprised of: a first arm 31 mounted on a base table 35; a second arm 32 connected by its proximal end to the distal end of the first arm 31; and a third arm 33 connected by its central portion to the distal end of the second arm 32. The first and second arms 31 and 32 are bent and stretched relative to each other so that the third arm 33 is operable. Wafer support portions 33A each for supporting a semiconductor wafer are formed at the opposite ends of the third arm 33, respectively. Accordingly, the transfer arm apparatus 30 can transfer two wafers at a time while supporting the wafers on the wafer support portions 33A, respectively. Moreover, as shown in FIGS. 9A and 9B, the second arm 32 has a long, narrow driving link 32A bidirectionally and pivotally connected by its proximal end to the axial shaft, and a pair of left and right driven links 32B, one on either side below the driving link 32A. The driven links 32B are symmetrically connected by their proximal ends to a proximal link 32C having an essentially square shape. The third arm 33 is connected to the distal ends of the driving link 32A and driven links 32B in a manner similar to the forgoing description, so that a link mechanism is constituted. Furthermore, a transmission 31B is arranged in the first arm 31, and is driven by a driving mechanism 31C. In the transmission 31B, the first rotational axis member (the axial shaft 32D) transmits a rotational driving force to the first pair of parallel links, and the second rotational axis member (the hollow axial shaft 32E) transmits a rotational driving force to the second pair of parallel links through the proximal link 32C.
However, although the transfer arm apparatus 30 can reduce time spent in transporting wafers during a manufacturing process, it still has shortcomings listed as following:
- (1) The transferring ability is limited by the lengths of the first and the second arms 31, 32, however, if the first and the second arms 31, 32 are too long, the moving stability of the third arm 33 will be adversely affected.
- (2) The structure of the transfer arm apparatus 30 is too complicated that it is not only expensive to manufacture and difficult to maintain, but also has high probability of breakdown.
- (3) The transfer arm apparatus 30 can only perform a rotation and a horizontal movement, but can not perform a vertical movement, that it is not suitable for transferring vertically arranged wafers or magazines.
- (4) As the wafer to be transfer by the transfer arm apparatus 30 is simply placed on the third arm 33 without being fasten by any holding device, it is not secured enough that the wafer in transportation thereby can easily drop by vibration.
SUMMARY OF THE INVENTION
In view of the disadvantages of prior art, the primary object of the present invention is to provide a multi-directional gripping apparatus capable of simultaneously fetching and positioning more than one workpiece to be processed by a mechanical platform in a successive manner, such that the operation efficiency of the mechanical platform as well as the gripping apparatus are optimized since there is no idle period for the mechanical platform and no holding for the gripping apparatus, thereby the manufacturing process is shortened and the throughput is increased.
To achieve the above object, the present invention provides a multi-directional gripping apparatus, comprising:
- a grabber, having a rotation shaft and a plurality of gripping arms being positioned centering around the rotation shaft while extending toward different directions in respective; and
- a driving mechanism, for driving the grabber to rotate, to move vertically, and to move horizontally.
Preferably, the multi-directional gripping apparatus further comprises a sensing unit, for detecting the position of a workpiece. In a preferred aspect, the sensing unit is arranged on the grabber. Moreover, a detection signal is generated by the sensing unit for controlling a corresponding gripping arm of the plural gripping arms to fetch the workpiece as soon as the position of the workpiece is detected by the sensing unit.
Preferably, the sensing unit further comprises two sensors, whereas the two sensors are orientated for enabling the sensing directions of the two to be perpendicular to each other.
Preferably, the grabber has two gripping arms, being positioned symmetrically to the rotation shaft of the grabber while extending horizontally toward directions opposite to each other.
Preferably, each gripping arm is connected to a vacuuming device for enabling the gripping arm to exert a suction force.
Preferably, at least a hole is arranged on a surface of each gripping arm contacting to a workpiece fetched thereby, wherein each hole is connected to the vacuuming device for enabling the gripping arm to exert a suction force on the fetched workpiece.
Preferably, each gripping arm is a horizontal-extending plate having a notch formed at the extending end thereof for enabling the extending end to be shaped like a “U” shape.
Preferably, the driving mechanism includes:
- a vertical driver, for driving the grabber to perform a linear vertical movement;
- a horizontal driver, for driving the grabber to perform a linear horizontal movement; and
- a rotation driver, for driving the grabber to rotate.
Preferably, the vertical driver further comprises:
- a rail device, composed of a vertically arranged rail, being adapted for the grabber to be arranged at the top end of the rail, and a seat, mounted on the rail for enabling the same to slide up and down the rail; and
- a power device, for providing power to the rail and thus driving the rail to move up and down while bring along the grabber to move vertically.
Preferably, the rail device is a ball spline, whereas the rail is a spline shaft and the seat is a spline sleeve of the ball spline.
Preferably, the vertical driver further comprises:
- a screw device, composed of a horizontally arranged screw and a follower, adapted for the grabber to be arranged thereon while being mounted on the screw for enabling the same to be driven by the screw to move reciprocatively along the axial direction of the screw; and
- a driving motor, for driving the screw to rotate and thus bringing the grabber arranged on the follower to move accordingly as the follower is driven to move reciprocatively with respect to the rotation of the screw.
Preferably, the rotation driver further comprises:
- a transmission part, connected to the rotation shaft of the grabber; and
- a power output device, for outputting power to the transmission part for enabling the transmission part to drive the rotation shaft to rotate.
Preferably, the power output device can be a motor reducer and the transmission part can be a belt.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a grabber according to a preferred embodiment of the invention.
FIG. 2 is a perspective view of a grabber, a driving mechanism, a positioning device and a storage magazine according to a preferred embodiment of the invention.
FIG. 3 to FIG. 8 are top views showing a serial of successive steps of using the gripping device of the invention to fetch workpieces.
FIG. 9A is a plan view showing a transfer arm apparatus disclosed in U.S. Pat. No. 6,068,704.
FIG. 9B is a cross-sectional view taken along line II-II in FIG. 9A.
FIG. 9C is a plan view showing an example of a semiconductor processing system employing the transfer arm apparatus shown in FIG. 9A
DESCRIPTION OF THE PREFERRED EMBODIMENT
For your esteemed members of reviewing committee to further understand and recognize the fulfilled functions and structural characteristics of the invention, several preferable embodiments cooperating with detailed description are presented as follows.
Referring to FIG. 1, which is a perspective view of a grabber according to a preferred embodiment of the invention. In FIG. 1, The gripping apparatus has a grabber 1, which is composed of a rotation shaft 11 and two panel-like gripping arms 12, 13, being positioned centering around the rotation shaft while extending toward opposite directions in respective. The two upper surfaces 131, 131 of the two panel-like gripping arms 12, 13 are used for carrying workpieces 5 while two notches 122, 13, are formed respectively at their corresponding extending ends of the two gripping arm 12, 13 for enabling the extending ends to be shaped like a “U” shape. The function of the notch is addressed in the description hereinafter.
Moreover, as seen in FIG. 1, two holes are arranged respectively on the upper surfaces 121, 131 of the two gripping arms 12, 13 while being positioned at locations corresponding to the positioning of the workpieces 5. The two holes 123, 133 are connected to a vacuuming device for enabling the two gripping arms 12, 13 to exert a suction force on the fetched workpieces 5 through the two holes 123, 133, such that the workpieces 5 can be adhered firmly on the upper surfaces 121, 131 of the two gripping arms 12, 13, and thus the falling of the workpieces 5 can be avoided. It is noted that the position and the amount of hole of each gripping arm are dependent on the appearance and size of the workpiece to be fetch thereby, and are not limited by that illustrated in the forgoing embodiment.
In a preferred aspect, a sensing unit 14 is arranged on the grabber 1, which is comprised of two sensors 141, 142, being orientated for enabling the sensing directions of the two to be perpendicular to each other. The sensing direction of the sensor 141 is orientated toward the external the grabber 1 in a horizontal manner, and thus the sensor 141 is enabled to detect the position of a workpiece in front of the moving direction of the grabber 1. Moreover, the sensing direction of the sensor 142 is orientated toward the top of the grabber 1 in a vertical manner, and thus the sensor 142 is enabled to detect whether there is a protrusion blocking the upward moving path of the grabber 1 as the grabber is driven to move up and down so that the collision between the vertically moving grabber 1 and a workpiece protruding over the grabber 1 can be avoid. Therefore, by the detection of the sensing unit 14, the accurate position of a workpiece can be detected, and thus a detection signal can be generated by the sensing unit 14 for controlling a corresponding gripping arm of the two gripping arms 12, 13 to fetch the detected workpiece. It is noted that the types and the amount of sensors of the sensing unit 14 are dependent on the appearance and size of the workpiece to be fetch thereby as well as the working environment, that each can be an optical sensor, an ultrasonic sensor, etc, or other types of sensor capable of detecting the position of the workpiece, which is known to those skilled in the art and thus is not described further herein.
Please refer to FIG. 2, which is a perspective view of a grabber, a driving mechanism, a positioning device and a storage magazine according to a preferred embodiment of the invention. As seen in FIG. 2, the gripping apparatus of the invention further comprises a driving mechanism including a vertical driver 2, a horizontal driver 3 and a rotation driver 4, respectively used for driving the grabber 1 to move vertically, to move horizontally, and to rotate.
The vertical driver 2 further comprises a rail device 21, whereas the rail device 21 can be a ball spline as shown in the embodiment of FIG. 2. In FIG. 2, the ball spline 21 is composed of a vertically arranged spline shaft 211, being adapted for the grabber 1 to be arranged at the top end of the spline shaft 211, and a spline sleeve 212, mounted on the spline shaft 211 for enabling the same to slide up and down the spline shaft 211, whereas the spline shaft 211 as well as the spline sleeve 212 are arranged on a base 22. Furthermore, the spline shaft 211 is controlled to move by a power device, that the spline shaft 211 can be driven to move up or down by the driving force provided from the power device, and thus the grabber 1 is brought to perform a linear vertical movement. It is noted that the rail device is not limited by the ball spline composed of the spline shaft 211 and the spline sleeve 212, that it can be a rail device composed of various rails, screws, bearings, etc., only if it can achieve the object of enabling the grabber 1 to move vertically.
Moreover, the horizontal driver 3 is comprised of a screw device 31 and a driving motor 32. Wherein, the screw device 31 is further composed of a horizontally arranged screw 311 and a follower, so that, as the screw 311 is driven to rotate by the driving motor 32, the rotation of the screw 311 will bring the follower to move reciprocatively along the axial direction of the screw 311, marked by the arrow A. The follower can be moved to a position that it is in contact with the base 22 of the vertical driver 2, and then the base 22 can be bring to move horizontally along with the moving of the follower while eventually driving the grabber 1 to perform a horizontal movement.
In addition, the rotation driver 4 is further composed of a transmission part and a power output device, whereas the transmission part can be a belt 41 and the power output device can be a motor reducer 42, as seen in FIG. 2. The belt 41 is used for connecting the motor reducer 42 to a wheel 43, whereas the wheel 43 is connected to the rotation shaft 11 of the grabber for bringing the rotation shaft 11 to rotate therewith. As the power of the motor reducer 42 is transmitted to the wheel 43 by the belt 41 in the manner that the wheel 43 is driven to rotate with the belt 41, the rotation shaft 11 is driven to rotate with the rotation of the wheel 42 and thus the gripping arms of the grabber is driven to rotate as well.
Summing up from the above description, the grabber of the invention can be driven to perform a linear vertical movement, to perform a linear horizontal movement, to rotate by the vertical driver 2, the horizontal driver 3 and the rotation driver 4 in respective. In addition, a control program can be used to control and coordinate the activations of the vertical driver 2, the horizontal driver 3 and the rotation driver 4. As for the distances that the linear vertical and horizontal movements can travel as well as the allowable maximum rotation angle, they are all variable and dependent upon the appearance and size of the workpiece to be fetch thereby as well as the working environment, working space and the configuration of the mechanical platform. In a preferred aspect, the structure of the aforesaid horizontal driver 3 shown in FIG. 2 can be employed as the vertical driver while the structure of the aforesaid vertical driver 2 shown in FIG. 2 can be employed as the horizontal driver, or the length of the spline shaft 211 as well as that of the screw 311 can varied with respect to actual requirement.
Please refer to FIG. 3 to FIG. 8, which are top views showing a series of successive steps of using the gripping device of the invention to fetch workpieces. As seen in FIG. 2, the storage magazine 6 has a plural layers of slot 61, each capable of receiving a horizontal-positioned wafer 9. In order to orient the wafer 9 for processing, a positioning device 7 is arranged at the vicinity of the horizontal driver 3, that the positioning device 7 is composed of a rotary seat 71 with suction ability, arranged at the center of the same, and a plurality of position docks 72, disposed surrounding the peripheral of the rotary seat 71. By placing the wafer 9 on the positioning device 7, the rotary seat 71 and the plural position docks can work together for orientating the wafer properly for enabling the same suitable to be processed. In FIG. 3, as the process performed by the mechanical platform 8, the wafer orientation operation performed by the positioning device 7 and the storage ability provided by the storage magazine 6 are all related to the operation of the grabber 1, the mechanical platform 8, the positioning device 7 and the storage magazine 6 should be place respectively at a location with respect to the routing of the grabber 1. In the embodiment shown in FIG. 3, the mechanical platform 8, the positioning device 7 and the storage magazine 6 are arranged surrounding the rotation shaft 11 of the grabber 1 while keeping a proper distance away from the same.
Referring to FIG. 3 and FIG. 4, as soon as the sensing unit 14 arranged on the grabber 1 detects the position of a wafer 9, which is stored in the storage magazine 6 and waiting to be processed, the grabber 1 will be driven to rotate by a specific angle, i.e. about 90 degrees, with respect to the rotation shaft 11 for enabling the gripping arm to reach toward the storage magazine 6 while extending under the wafer 9, as shown in FIG. 4.
Referring to FIG. 4 and FIG. 5, as the gripping arm 12 is in contact with the bottom of the wafer 9, the wafer 9 is drawn to cling to the gripping arm 12 by the suction of the hole 123 formed on the gripping arm 12 and connected to a vacuuming device. Thereafter, the grabber 1 is driven to back up a specific distance for taking the wafer 9 out of the storage magazine 6. As the wafer 9 is exiting from the storage magazine 6 with its cutting edge 91 being placed obliquely, as seen in FIG. 5, the grabber 1 is again driven to rotate about 90 degrees for positioning the gripping arm 12 over the positioning device 7.
Referring to FIG. 5 and FIG. 6, as the gripping arm 12 is positioned over the positioning device 7, the suction of the hole 123 is disabled while driving the grabber 1 to descend so as to place the wafer 9 on the position docks 72 of the position device 7, and then the wafer 9 can be orientated and prepared for processing. It is noted that as there is a notch 122 formed at the extending end of the gripping arm 12, the interference between the gripping arm 12 and the rotary seat 71 can be avoided when the gripping arm 12 is descending to place the wafer 9 on the rotary seat 71 and the position docks 72. In FIG. 6, the positioning device 7 will specifically orientate the cutting edge 91 of the wafer 9 to face toward a specific direction, represented by arrow B, moreover, the gripping arm 13, disposed symmetrical and opposite to the gripping arm 12, is extending under the wafer 9a of the mechanical platform 8 while the gripping arm 12 is just positioned over the positioning device 7.
Referring to FIG. 6 and FIG. 7, as soon as the orientation of the wafer 9 is achieved by the positioning device 7, the processing of wafer 9a performed by the mechanical platform 8 is also accomplished. Then, the grabber 1 is driven to raise, so that the gripping arms 12, 13 can simultaneously pick up the wafer 9 and the wafer 9a while using the holes 123, 133 with suction to draw the two wafers to fixedly adhere to the two gripping arms 12, 13 in respective. Thereafter, the grabber 1 is driven to rotate for enabling the gripping arm 13 to face toward the storage magazine 6 while insetting the wafer 9a into the storage magazine 6, as shown in FIG. 7.
Referring to FIG. 7 and FIG. 8, after the wafer 9a is properly stored in the storage magazine 6, the grabber 1 is driven to rotate again for enabling the gripping arm 12 to put the orientated wafer 9 on the mechanical platform 8 for processing. Thereafter, the grabber 1 is driven to return to its initial position shown in FIG. 3 and then is ready to fetch another wafer for processing.
To sum up, the present invention provides a multi-directional gripping apparatus capable of performing material-fetching and positioning tasks simultaneously during a manufacturing process so as to make the best use of a specific processing time while performing in maximum efficiency, by which it can help to shorten a manufacturing process and thus improve production yield.
Comparing the multi-directional gripping apparatus of the invention with the conventional transfer arm apparatus shown in FIG. 9A and FIG. 9B, the multi-directional gripping apparatus is advantageous as following:
- (1) The multi-directional gripping apparatus of the invention is able to function without the first, the second and the third arms of the prior-art transfer arm apparatus that it is comparatively simple in structure.
- (2) As the grabber 1 is driven to rotate by the driving mechanism 4 directly while the third arm is indirectly driven by the driving mechanism 31C through the a link mechanism composed of the first arm 31 and the second arm 32, the driving of the multi-directional gripping apparatus of the invention is more precise.
- (3) As the driving mechanism 4 can drive the grabber 1 to rotate and move horizontally as well as vertically while the driving mechanism 31C can only drive the first arm 31 and the transmission 31B to rotate, the multi-directional gripping apparatus of the invention is capable of three-dimensional moving ability that is preferred comparing to the two-dimensional movement of the prior art. As seen in FIG. 9C, A wafer W is transferred by the transfer arm apparatus 23 from a magazine 19 into one of the process chambers that there is no detailed operation description of the transfer arm apparatus 23 being disclosed in U.S. Pat. No. 6,068,704. However, the grapping apparatus of the invention is capable of vertical transferring ability that it is suitable to be applied for vertically arranged magazines.
- (4) As the two gripping arms 12, 13 respectively has two holes 123, 133 connected to a vacuuming device for enabling the two gripping arms 12, 13 to exert a suction force on the fetched workpieces 5 therethrough, the workpieces 5 can be adhered firmly on the upper surfaces 121, 131 of the two gripping arms 12, 13. However, the transfer arm apparatus of prior art do not equipped with similar holding device.
- (5) By the detection of the sensing unit 14 of the multi-directional gripping apparatus of the invention, the accurate position and height of a workpiece can be detected. However, the transfer arm apparatus of prior art do not equipped with similar sensing unit.
- (6) Comparing to those complicated, expensive to manufacture and hard to maintain prior-art transfer arm apparatuses, the multi-directional gripping apparatus of the invention is simple in structure, inexpensive to manufacture and easy to maintain, not to mention it has low probability of breakdown.
While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
Patent Application
20070217897
