Wafer Grinding Apparatus and Method for Placing and Retrieving Multiple Wafers

Not applicable.

The present invention relates to a component used in the wafer grinding process, specifically a wafer grinding apparatus and a method for placing and retrieving multiple wafers.

A wafer grinding apparatus comprises several wafer turntables, a driving device, a grinding device, and a transfer device. The driving device drives each wafer turntable to operate in a cycle. Each wafer turntable is pierced with multiple positioning holes to hold multiple wafers. The grinding device processes each wafer, and the transfer device relocates each wafer to its respective positioning hole and removes it from the wafer turntable upon completion of the grinding process.

The transfer device comprises a placement unit, a processing unit, and a robotic arm that individually places multiple wafers in different positioning holes.

Upon completion of the grinding process, the transfer device individually transfers the multiple processed wafers out of the grinding process.

Because the transfer device transfers multiple wafers individually to their respective wafer turntables, the overall efficiency of the process can be improved.

In the absence of a record of the processing history of each wafer, i.e., the grinding process of the wafer, which is required to record not only the length of time the wafer is ground, but also the wafer turntable and the positioning holes in which the wafer is positioned, the transfer device is unable to identify the wafer turntable and the positioning holes in which the wafer is transferred, which is not conducive to tracking the processing history of each wafer.

The main purpose of the present invention is to provide a wafer grinding apparatus and a method for placing and retrieving multiple wafers.

In order to achieve the above purpose, the present invention employs the following technical solution:

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.

A method for placing and retrieving multiple wafers, which is performed using the wafer grinding apparatus according to claim, 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.

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.

The present invention is capable of simultaneously transferring multiple wafers to the selected wafer turntable, and upon completion of the grinding process, the multiple wafers can also simultaneously be retrieved from the wafer turntable, thereby enhancing the overall efficiency of the grinding process. The present invention is also capable of recording for each wafer the first placement mark of the first placement structure, the identification mark corresponding to the wafer turntable, and the hole position mark corresponding to the positioning hole, which can be bonded together with the identity identification code of each wafer to form the grinding record, which is advantageous for tracking the processing history of each wafer.

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.

As shown in, a wafer grinding apparatus comprises several wafer turntables, a driving device, a grinding device, a front table, a rear table, a transfer device, and a control unit. Each wafer turntableis intermittently arranged on the driving device. The driving deviceis used to cyclically operate each wafer turntable, which rotates simultaneously during operation. Each wafer turntableis pierced with several positioning holes, which are arranged equidistantly in this embodiment, each for placing and positioning a wafer. The grinding deviceis used to grind the wafersplaced on each wafer turntable. Since the specifics of the driving deviceand the grinding deviceare 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.

Each wafer turntableforms an identification markto distinguish and identify each wafer turntable, and a first positioning markto identify the placement center of the positioning holes. In this embodiment, each first positioning markis located at the radial center of each wafer turntable, with the positioning holesarranged around the first positioning mark. Several hole position marksare formed in the vicinity of each positioning holefor distinguishing and identifying those positioning holes.

The identification mark, the first positioning mark, and the hole position markmay be numbers, text, graphics, or a combination thereof. Each wafer turntablehas a distinct identification mark, which in this embodiment is selected to be numbered, while the first positioning markand the hole position marksare each selected to be the hole through the wafer turntable, and each hole position markis selected to be the hole with a different diameter.

The front tableintermittently forms several first placement structuresand first placement marksin accordance with the number and arrangement of the positioning holesof the wafer turntablesfor placing the wafersto be ground, and each first placement markis used to distinguish and identify each first placement structure. The front tablealso forms a second positioning markfor identifying the placement center of each first placement structures.

The rear tableintermittently forms several second placement structuresin accordance with the number and arrangement of the positioning holesof the wafer turntablesfor placing the ground wafers. The rear tablealso forms a third positioning markfor identifying the placement center of the second placement structure.

The transfer deviceis used to transfer the wafersbetween the front table, the wafer turntables, and the rear table. It comprises a placement unitand a robotic arm. The placement unitis mounted at the working endof the robotic arm, which maneuvers the placement unittoward or away from a selected wafer turntable.

The placement unitcomprises an adjustment module, multiple lifters, multiple suction cup modules, and an image capture device. The adjustment moduleis connected to the robotic armand includes an actuated rotary mount. Each of the liftersis intermittently configured on a radial periphery of the mountaround a rotatable center of the mount, and each lifteris connected to each suction cup module, respectively, enabling the liftersto respectively raise and lower the suction cup moduletoward or away from each wafer. Each of the suction cup modulescomprises three vacuum suction cupsfor respectively sucking and releasing the wafer, wherein the number of vacuum suction cupsin each suction cup modulevaries as needed, provided that each suction cup modulehas at least one vacuum suction cup.

The image capture device, which is attached on the adjustment module, is used to capture images of the wafer turntable, the front table, and the rear table. In this embodiment, the image capture deviceis 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).

The control unit, which is mainly composed of electronic circuits, is optionally placed at a suitable position of the wafer grinding apparatus. It includes a programmable controller, a storage medium, and a microprocessor. The programmable controllerand the storage mediumare electrically connected to the microprocessor, respectively. Meanwhile, the programmable controlleris electrically connected to the placement unitand the robotic arm. The storage mediumis a readable and writable memory medium used to store the grinding records of the wafers, and the microprocessoris electrically connected to the image capture device.

The microprocessorexecutes an image recognition program to identify the images captured by the image capture device. It controls the robotic armand the placement unitthrough the programmable controllerbased on the identification results. This allows the wafersto be simultaneously placed on a selected wafer turntablefor grinding, and the ground wafersto be simultaneously removed from the selected wafer turntable. The microprocessoralso binds the identity identification code of each waferwith the corresponding first placement mark, the identification mark, and the hole position markto form multiple grinding records for each corresponding wafer, respectively.

The microprocessorexecutes an image recognition program to identify the images captured by the image capture device. It controls the robotic armand the placement unitthrough the programmable controllerbased on the identification results. This allows the wafersto be simultaneously placed on a selected wafer turntablefor grinding, and the ground wafersto be simultaneously removed from the selected wafer turntable. The microprocessoralso binds the identity identification code of each waferwith the corresponding first placement mark, the identification mark, and the hole position markto form multiple grinding records for each corresponding wafer, respectively.

Retrieving wafer by placement unit: The robotic armmoves the placement unitto the above space of the front table. Based on the image identification result of the front tablecaptured by the image capture device, the control unitcalibrates each suction cup moduleto align with the multiple wafersto be ground, each pre-positioned on the first placement structure. The microprocessorrecords the respective first placement markon which the waferis placed. The control unitthen controls each vacuum suction cupin each suction cup moduleto suck the corresponding wafer, respectively, and records each corresponding first placement markof the wafer.

The process for aligning each suction cup modulewith each waferusing the transfer deviceis as follows: The transfer devicemoves to position the center of the placement unitto align with the second positioning mark. The control unitthen controls the adjustment moduleto allow the mountto either rotate or remain stationary, based on the specific alignment differences between each waferand its corresponding suction cup module. This ensures that each suction cup moduleis aligned with its respective wafer.

Aligning placement unit with wafer turntable: The robotic armmoves the placement unitto the above space of the selected wafer turntable. The image capture devicecaptures the image of the identification markof the wafer turntable, and the microprocessorexecutes the image recognition program to identify and record the wafer turntableon which the wafersare placed. The image capture devicealso captures the image of the first positioning markon the wafer turntable. The microprocessoridentifies the first positioning markand calculates the axial distance deviation for positioning the placement unitrelative to the first positioning mark. The control unitthen controls the robotic armto move or remain stationary to compensate for any distance deviations. The placement unitaligns vertically with the first positioning mark, and the image capture devicecaptures the image of the shape of each positioning holeon the wafer turntablealong with the corresponding hole position mark. The microprocessoridentifies these images to calculate the angular deviation between each positioning holeand its corresponding suction cup modulecentered at the first positioning mark. Based on this calculation, the control unitcontrols the adjustment moduleto rotate or not to rotate the mountto compensate for the angular deviation. This alignment ensures that each suction cup moduleis vertically aligned with each of the positioning holes. Consequently, the control unitcan precisely control the transfer deviceto adjust the alignment of each suction cup modulerelative to each positioning holebased on the image identification results of the wafer turntableby the image capture device. In addition, the control unitalso records the identification markof the wafer turntableand the hole position markof each positioning holecorresponding to each wafer.

Placing wafer by placement unit: The control unitcontrols each suction cup moduleto release each waferinto its respective positioning hole, so that each of the positioning holeson the wafer turntableis placed with a wafer, enabling the driving deviceand the grinding deviceto be activated to complete the grinding process for each wafer.

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 waferto be ground can be placed into each of the positioning holesof the wafer turntables, handling multiple wafers simultaneously. Whereby, the driving deviceand the grinding devicecan be operated to complete the grinding process for each wafer.

Aligning placement unit with wafer: After the grinding process is completed, the robotic armmoves the placement unitto the above space of the selected wafer turntable. Based on the image identification result of the wafer turntablecaptured by the image capture device, the control unitcontrols the transfer deviceto calibrate each suction cup moduleto align with each ground waferplaced on each wafer turntable, and the control unitalso records the identification markof the wafer turntableand the hole position markof each positioning holecorresponding to each wafer.

Transferring wafer by transfer device: Each of the suction cup modulessucks each wafer, respectively, and lifts each waferaway from the wafer turntable, and the robotic armmoves the placement unitto the above of the rear table. Based on the image identification result captured by the image capture device, the control unitcontrols the transfer deviceto calibrate each suction cup moduleto align with each second placement structureon the rear table. The placement unitthen releases each ground waferonto each second placement structure.

Storing grinding records: The microprocessorbinds the identity identification code of each waferwith its corresponding first placement mark, identification mark, and hole position markto form corresponding multiple grinding records for each wafer. Each of the records is then stored in the storage medium.

The transfer deviceis capable of simultaneously transferring multiple wafersfrom the front tableto the selected wafer turntable. After the grinding devicecompletes the grinding process, the transfer deviceis also capable of simultaneously retrieving these wafersfrom the wafer turntableand transferring them to the rear table. This efficient approach significantly reduces the time required to place and retrieve the wafers, thereby enhancing the overall efficiency of the wafer grinding apparatus during the grinding process.

During the process of placing each of the waferson the selected wafer turntableand retrieving each of the wafersfrom the wafer turntable, the transfer devicecan identify the first placement structure, the wafer turntable, and the positioning holeon which each waferis placed, and record the corresponding first placement mark, the identification mark, and the hole position markfor each waferand associate them with the identity identification code of each waferto form the grinding record stored in the storage medium. This facilitates tracking the processing history of each wafer.

In addition, the rear tableforms 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 unitrecords each second placement markof each second placement structurecorresponding to each wafer, and the microprocessorfurther binds the corresponding second placement markused to identify the second placement structureon which each waferis placed to form the grinding record corresponding to each wafer.

Each suction cup modulefurther includes a positioning frameon which each vacuum suction cupis installed. Additionally, each of the liftersconsists of a pneumatic cylinder, with a piston rodof each pneumatic cylinderoperating axially in an upward and downward reciprocating motion. These piston rodsare each connected to the corresponding positioning frame, enabling the upward and downward operation of each suction cup module.

As shown in, Embodimentdiffers from Embodimentprimarily in the type of robotic arm.