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.

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.