WAFER GRINDING APPARATUS AND METHOD FOR PLACING AND RETRIEVING MULTIPLE WAFERS

Abstract

Disclosed is a wafer grinding apparatus and a method for placing and retrieving multiple wafers. The wafer grinding apparatus has several wafer turntables, a driving device, a grinding device, a front table, a rear table, a transfer device, and a control unit. Each wafer turntable features several positioning holes for locating wafers and forms an identification mark for distinguishing and identifying each wafer turntable, a first positioning mark for identifying the placement center of the positioning holes, and a hole position mark for identifying each positioning hole. The wafer grinding apparatus is capable of transferring multiple wafers simultaneously and binding the corresponding identification mark and hole position mark of each wafer to form grinding records that facilitates tracking the processing history of each wafer.

Claims

1. A wafer grinding apparatus, comprising several wafer turntables, a driving device, a grinding device, a front table, a rear table, a transfer device, and a control unit, wherein each wafer turntable is intermittently arranged on the driving device and is equidistantly pierced with several positioning holes for placing wafers, and the grinding device is used to grind each of the wafers; each wafer turntable forms an identification mark for distinguishing and identifying the wafer turntable, a first positioning mark for identifying the placement center of the positioning holes, and several hole position marks in the vicinity of each positioning hole for identifying each positioning hole; the front table intermittently forms several first placement structures and first placement marks in accordance with the number and arrangement of the positioning holes of the wafer turntables for placing the wafers to be ground, and each first placement mark is used to distinguish and identify each first placement structure; the front table also forms a second positioning mark for identifying the placement center of each first placement structures; the rear table intermittently forms several second placement structures in accordance with the number and arrangement of the positioning holes of the wafer turntables for placing the ground wafers; the rear table also forms a third positioning mark for identifying the placement center of the second placement structure; the transfer device comprises a placement unit and a robotic arm, the placement unit being mounted at the working end of the robotic arm; the placement unit comprises an adjustment module, multiple lifters, multiple suction cup modules, and an image capture device, wherein the adjustment module is connected to the robotic arm and includes an actuated rotary mount; each of the lifters is intermittently configured on a radial periphery of the mount around a rotatable center of the mount, and each lifter is connected to each suction cup module, respectively, enabling the lifters to respectively raise and lower the suction cup module toward or away from each wafer; each of the suction cup modules comprises at least one vacuum suction cup for respectively sucking and releasing the wafer; the image capture device, which is attached on the adjustment module, is used to capture images; the control unit, which is mainly composed of electronic circuits, includes a programmable controller, a storage medium, and a microprocessor, wherein the programmable controller and the storage medium are electrically connected to the microprocessor, respectively; the programmable controller is also electrically connected to the placement unit and the robotic arm; the storage medium is a readable and writable memory medium used to store the grinding records of the wafers; and the microprocessor is electrically connected to the image capture device; the microprocessor executes an image recognition program to identify the images captured by the image capture device and controls the robotic arm and the placement unit through the programmable controller based on the identification results to allow the placement or retrieval of the multiple wafers simultaneously; the microprocessor also binds the identity identification code of each wafer with the corresponding first placement mark, the identification mark, and the hole position mark to form multiple grinding records for each corresponding wafer, respectively.

2. The wafer grinding apparatus according to claim 1, wherein the rear table forms several second placement marks, each for distinguishing and identifying the second placement structures; the microprocessor binds the identity identification code of each wafer with the corresponding first placement mark, the identification mark, and the hole position mark to form multiple grinding records for each corresponding wafer, respectively.

3. A method for placing and retrieving multiple wafers, which is performed using the wafer grinding apparatus according to claim 1, comprising the following steps: retrieving wafer by placement unit: the robotic arm moves the placement unit to the above space of the front table, the control unit, based on the result of identifying the image captured by the image capture device, controls the transfer device, respectively, to calibrate each suction cup module to align with the multiple wafers to be ground that is pre-positioned on the first placement structure, then each suction cup module sucks the corresponding wafer, respectively, and the control unit records each corresponding first placement mark of the respective wafer; aligning placement unit with wafer turntable: the robotic arm moves the placement unit to the above space of a selected wafer turntable, and the control unit controls the transfer device, based on the result of identifying the image captured by the image capture device, to align each suction cup module with the respective positioning hole; the control unit records the identification mark of the wafer turntable and the hole position mark of each positioning hole corresponding to each wafer; placing wafer by placement unit: each of the suction cup modules releases each wafer into its respective positioning hole, so that each of the positioning holes on the wafer turntable is placed with a wafer, enabling the driving device and the grinding device to be activated to complete the grinding process for each wafer; aligning placement unit with wafer: after the grinding process is completed, the robotic arm moves the placement unit to the above space of the selected wafer turntable, and the control unit, based on the result of identifying the images captured by the image capture device, controls the transfer device to calibrate each suction cup module to align with each ground wafer placed on each wafer turntable, and the control unit records the identification mark of the wafer turntable and the hole position mark of each positioning hole corresponding to each wafer; transferring wafer by transfer device: each of the suction cup modules sucks each wafer, respectively, and lifts each wafer away from the wafer turntable, then the robotic arm moves the placement unit to the above of the rear table; the control unit, based on the result of identifying the image captured by the image capture device, controls the transfer device to calibrate each suction cup module to align with each second placement structure on the rear table, and the placement unit releases each ground wafer onto each second placement structure; and storing grinding records: the microprocessor binds the identity identification code of each wafer with its corresponding first placement mark, identification mark, and hole position mark to form corresponding multiple grinding records for each wafer, each of which is then stored in the storage medium.

4. The method for placing and retrieving multiple wafers according to claim 3, wherein the rear table forms several second placement marks, each of which is used to distinguish and identify each of the second placement structures; during the wafer transfer step of the placement unit, the control unit records each second placement mark of each second placement structure corresponding to each wafer, and the microprocessor further binds the corresponding second placement mark on which each wafer is placed to form the grinding record corresponding to each wafer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a schematic perspective view of part of the wafer grinding apparatus in Embodiment 1 of the present invention.

[0026] FIG. 2 is a top view of part of the wafer grinding apparatus in Embodiment 1.

[0027] FIG. 3 is an enlarged view of part of FIG. 2.

[0028] FIG. 4 is another enlarged view of part of FIG. 2.

[0029] FIG. 5 is another enlarged view of part of FIG. 2.

[0030] FIG. 6 is a perspective view of part of the wafer grinding apparatus in Embodiment 1.

[0031] FIG. 7 is a cross-sectional view of the placement unit in Embodiment 1 of the present invention.

[0032] FIG. 8 is a circuit block diagram of the transfer device in Embodiment 1.

[0033] FIG. 9 is a flowchart of the method for placing and retrieving wafers in Embodiment 1.

[0034] FIG. 10 is a perspective view of the wafer grinding apparatus placing wafers onto the wafer turntable in Embodiment 1.

[0035] FIG. 11 is a schematic top view of the wafer grinding apparatus in Embodiment 1 of the present invention, showing the adjustment of the wafers to align with the positioning holes.

[0036] FIG. 12 is a perspective view of part of the wafer grinding apparatus in Embodiment 2.

[0037] FIG. 13 is an enlarged top view of part of the wafer turntable in Embodiment 3.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Please refer to the drawings for a preferred embodiment of the present invention, but these embodiments are for illustrative purposes only and are not subject to the limitations of this structure for patent application.

[0039] As shown in FIGS. 1 through 8, a wafer grinding apparatus comprises several wafer turntables 10, a driving device 20, a grinding device 30, a front table 40, a rear table 50, a transfer device 60, and a control unit 70. Each wafer turntable 10 is intermittently arranged on the driving device 20. The driving device 20 is used to cyclically operate each wafer turntable 10, which rotates simultaneously during operation. Each wafer turntable 10 is pierced with several positioning holes 11, which are arranged equidistantly in this embodiment, each for placing and positioning a wafer 90. The grinding device 30 is used to grind the wafers 90 placed on each wafer turntable 10. Since the specifics of the driving device 20 and the grinding device 30 are well-known to those skilled in the art and are not necessarily related to the technical characteristics of the present invention, detailed descriptions will be omitted.

[0040] Each wafer turntable 10 forms an identification mark 12 to distinguish and identify each wafer turntable, and a first positioning mark 13 to identify the placement center of the positioning holes 11. In this embodiment, each first positioning mark 13 is located at the radial center of each wafer turntable 10, with the positioning holes 11 arranged around the first positioning mark 13. Several hole position marks 14 are formed in the vicinity of each positioning hole 11 for distinguishing and identifying those positioning holes 11.

[0041] The identification mark 12, the first positioning mark 13, and the hole position mark 14 may be numbers, text, graphics, or a combination thereof. Each wafer turntable 10 has a distinct identification mark 12, which in this embodiment is selected to be numbered, while the first positioning mark 13 and the hole position marks 14 are each selected to be the hole through the wafer turntable 10, and each hole position mark 14 is selected to be the hole with a different diameter.

[0042] The front table 40 intermittently forms several first placement structures 41 and first placement marks 42 in accordance with the number and arrangement of the positioning holes 11 of the wafer turntables 10 for placing the wafers 90 to be ground, and each first placement mark 42 is used to distinguish and identify each first placement structure 41. The front table 40 also forms a second positioning mark 43 for identifying the placement center of each first placement structures 41.

[0043] The rear table 50 intermittently forms several second placement structures 51 in accordance with the number and arrangement of the positioning holes 11 of the wafer turntables 10 for placing the ground wafers 90. The rear table 50 also forms a third positioning mark 53 for identifying the placement center of the second placement structure 51.

[0044] The transfer device 60 is used to transfer the wafers 90 between the front table 40, the wafer turntables 10, and the rear table 50. It comprises a placement unit 61 and a robotic arm 62. The placement unit 61 is mounted at the working end 63 of the robotic arm 62, which maneuvers the placement unit 61 toward or away from a selected wafer turntable 10.

[0045] The placement unit 61 comprises an adjustment module 64, multiple lifters 65, multiple suction cup modules 66, and an image capture device 67. The adjustment module 64 is connected to the robotic arm 62 and includes an actuated rotary mount 642. Each of the lifters 65 is intermittently configured on a radial periphery of the mount 642 around a rotatable center of the mount 642, and each lifter 65 is connected to each suction cup module 66, respectively, enabling the lifters 65 to respectively raise and lower the suction cup module 66 toward or away from each wafer 90. Each of the suction cup modules 66 comprises three vacuum suction cups 662 for respectively sucking and releasing the wafer 90, wherein the number of vacuum suction cups 662 in each suction cup module 66 varies as needed, provided that each suction cup module 66 has at least one vacuum suction cup 662.

[0046] The image capture device 67, which is attached on the adjustment module 64, is used to capture images of the wafer turntable 10, the front table 40, and the rear table 50. In this embodiment, the image capture device 67 is a camera lens having a photosensitive element (not shown). Specific examples of the photosensitive element include Charge-coupled Device (CCD) and Complementary Metal-Oxide-Semiconductor (CMOS).

[0047] The control unit 70, which is mainly composed of electronic circuits, is optionally placed at a suitable position of the wafer grinding apparatus. It includes a programmable controller 71, a storage medium 72, and a microprocessor 73. The programmable controller 71 and the storage medium 72 are electrically connected to the microprocessor 73, respectively. Meanwhile, the programmable controller 71 is electrically connected to the placement unit 61 and the robotic arm 62. The storage medium 72 is a readable and writable memory medium used to store the grinding records of the wafers 90, and the microprocessor 73 is electrically connected to the image capture device 67.

[0048] The microprocessor 73 executes an image recognition program to identify the images captured by the image capture device 67. It controls the robotic arm 62 and the placement unit 61 through the programmable controller 71 based on the identification results. This allows the wafers 90 to be simultaneously placed on a selected wafer turntable 10 for grinding, and the ground wafers 90 to be simultaneously removed from the selected wafer turntable 10. The microprocessor 73 also binds the identity identification code of each wafer 90 with the corresponding first placement mark 42, the identification mark 12, and the hole position mark 14 to form multiple grinding records for each corresponding wafer 90, respectively.

[0049] The microprocessor 73 executes an image recognition program to identify the images captured by the image capture device 67. It controls the robotic arm 62 and the placement unit 61 through the programmable controller 71 based on the identification results. This allows the wafers 90 to be simultaneously placed on a selected wafer turntable 10 for grinding, and the ground wafers 90 to be simultaneously removed from the selected wafer turntable 10. The microprocessor 73 also binds the identity identification code of each wafer 90 with the corresponding first placement mark 42, the identification mark 12, and the hole position mark 14 to form multiple grinding records for each corresponding wafer 90, respectively.

[0050] Retrieving wafer by placement unit: The robotic arm 62 moves the placement unit 61 to the above space of the front table 40. Based on the image identification result of the front table 40 captured by the image capture device 67, the control unit 70 calibrates each suction cup module 66 to align with the multiple wafers 90 to be ground, each pre-positioned on the first placement structure 41. The microprocessor 73 records the respective first placement mark 42 on which the wafer 90 is placed. The control unit 70 then controls each vacuum suction cup 662 in each suction cup module 66 to suck the corresponding wafer 90, respectively, and records each corresponding first placement mark 42 of the wafer 90.

[0051] The process for aligning each suction cup module 66 with each wafer 90 using the transfer device 60 is as follows: The transfer device 60 moves to position the center of the placement unit 61 to align with the second positioning mark 43. The control unit 70 then controls the adjustment module 66 to allow the mount 642 to either rotate or remain stationary, based on the specific alignment differences between each wafer 90 and its corresponding suction cup module 66. This ensures that each suction cup module 66 is aligned with its respective wafer 90.

[0052] Aligning placement unit with wafer turntable: The robotic arm 62 moves the placement unit 61 to the above space of the selected wafer turntable 10. The image capture device 67 captures the image of the identification mark 12 of the wafer turntable 10, and the microprocessor 73 executes the image recognition program to identify and record the wafer turntable 10 on which the wafers 90 are placed. The image capture device 67 also captures the image of the first positioning mark 13 on the wafer turntable 10. The microprocessor 73 identifies the first positioning mark 13 and calculates the axial distance deviation for positioning the placement unit 61 relative to the first positioning mark 13. The control unit 70 then controls the robotic arm 62 to move or remain stationary to compensate for any distance deviations. The placement unit 61 aligns vertically with the first positioning mark 13, and the image capture device 67 captures the image of the shape of each positioning hole 11 on the wafer turntable 10 along with the corresponding hole position mark 14. The microprocessor 73 identifies these images to calculate the angular deviation between each positioning hole 11 and its corresponding suction cup module 66 centered at the first positioning mark 13. Based on this calculation, the control unit 70 controls the adjustment module 64 to rotate or not to rotate the mount 642 to compensate for the angular deviation. This alignment ensures that each suction cup module 66 is vertically aligned with each of the positioning holes 11. Consequently, the control unit 70 can precisely control the transfer device 60 to adjust the alignment of each suction cup module 66 relative to each positioning hole 11 based on the image identification results of the wafer turntable 10 by the image capture device 67. In addition, the control unit 70 also records the identification mark 12 of the wafer turntable 10 and the hole position mark 14 of each positioning hole 11 corresponding to each wafer 90.

[0053] Placing wafer by placement unit: The control unit 70 controls each suction cup module 66 to release each wafer 90 into its respective positioning hole 11, so that each of the positioning holes 11 on the wafer turntable 10 is placed with a wafer 90, enabling the driving device 20 and the grinding device 30 to be activated to complete the grinding process for each wafer 90.

[0054] By repeating the steps of retrieving the wafer using the placement unit, aligning the placement unit with the wafer turntable, and placing the wafer with the placement unit as described, each wafer 90 to be ground can be placed into each of the positioning holes 11 of the wafer turntables 10, handling multiple wafers simultaneously. Whereby, the driving device 20 and the grinding device 30 can be operated to complete the grinding process for each wafer 90.

[0055] Aligning placement unit with wafer: After the grinding process is completed, the robotic arm 62 moves the placement unit 61 to the above space of the selected wafer turntable 10. Based on the image identification result of the wafer turntable 10 captured by the image capture device 67, the control unit 70 controls the transfer device 60 to calibrate each suction cup module 66 to align with each ground wafer 90 placed on each wafer turntable 10, and the control unit 70 also records the identification mark 12 of the wafer turntable 10 and the hole position mark 14 of each positioning hole 11 corresponding to each wafer 90.

[0056] Transferring wafer by transfer device: Each of the suction cup modules 66 sucks each wafer 90, respectively, and lifts each wafer 90 away from the wafer turntable 10, and the robotic arm 62 moves the placement unit 61 to the above of the rear table 50. Based on the image identification result captured by the image capture device 67, the control unit 70 controls the transfer device 60 to calibrate each suction cup module 66 to align with each second placement structure 51 on the rear table 50. The placement unit 61 then releases each ground wafer 90 onto each second placement structure 51.

[0057] Storing grinding records: The microprocessor 73 binds the identity identification code of each wafer 90 with its corresponding first placement mark 42, identification mark 12, and hole position mark 14 to form corresponding multiple grinding records for each wafer 90. Each of the records is then stored in the storage medium 72.

[0058] The transfer device 60 is capable of simultaneously transferring multiple wafers 90 from the front table 40 to the selected wafer turntable 10. After the grinding device 30 completes the grinding process, the transfer device 60 is also capable of simultaneously retrieving these wafers 90 from the wafer turntable 10 and transferring them to the rear table 50. This efficient approach significantly reduces the time required to place and retrieve the wafers 90, thereby enhancing the overall efficiency of the wafer grinding apparatus during the grinding process.

[0059] During the process of placing each of the wafers 90 on the selected wafer turntable 10 and retrieving each of the wafers 90 from the wafer turntable 10, the transfer device 60 can identify the first placement structure 41, the wafer turntable 10, and the positioning hole 11 on which each wafer 90 is placed, and record the corresponding first placement mark 42, the identification mark 12, and the hole position mark 14 for each wafer 90 and associate them with the identity identification code of each wafer 90 to form the grinding record stored in the storage medium 72. This facilitates tracking the processing history of each wafer 90.

[0060] In addition, the rear table 50 forms several second placement marks 52, each of which is used to distinguish and identify each of the second placement structures 51.

[0061] During the wafer transfer step of the placement unit, the control unit 70 records each second placement mark 52 of each second placement structure 51 corresponding to each wafer 90, and the microprocessor 73 further binds the corresponding second placement mark 52 used to identify the second placement structure 51 on which each wafer 90 is placed to form the grinding record corresponding to each wafer 90.

[0062] Each suction cup module 66 further includes a positioning frame 664 on which each vacuum suction cup 662 is installed. Additionally, each of the lifters 65 consists of a pneumatic cylinder 652, with a piston rod 654 of each pneumatic cylinder 652 operating axially in an upward and downward reciprocating motion. These piston rods 654 are each connected to the corresponding positioning frame 664, enabling the upward and downward operation of each suction cup module 66.

[0063] As shown in FIG. 12, Embodiment 2 differs from Embodiment 1 primarily in the type of robotic arm 62.

[0064] As shown in FIG. 13, Embodiment 3 primarily differs from Embodiment 1 in that each hole position mark 14 is a hole of a different shape.