SYSTEM AND METHOD FOR POLISHING AND GRINDING WAFERS

Abstract

The present invention discloses a system for polishing and grinding wafers, comprising a rack and a loading unit, a transfer unit, a processing unit, and a pickup unit arranged on the rack, wherein a first pickup section of the pickup unit picks up wafers from the loading unit, a robot arm drives a robot hand to move the wafers to the transfer unit; the transfer unit positions the wafers, several pickup heads of a second pickup section pick up several of the wafers positioned in the transfer unit, the robot arm drives the robot hand to move the wafers to processing stations of the processing unit; the processing unit performs polishing and grinding operations on the wafers.The robot arm of the present invention is capable of picking up wafers from the loading unit and the transfer unit, and the second picking section comprises multiple picking heads that can pick up several wafers simultaneously to increase production efficiency and improve wafer quality. The present invention also provides a method for polishing and grinding wafers, in which the above-described system for polishing and grinding wafers is used to increase production efficiency, ensure the quality of wafer processing, and reduce the workload of the operators.

Description

TECHNICAL AREA

[0001] The present invention relates to the technical field of wafer production plants and their peripheral equipment, and in particular to a method for polishing and grinding wafers. STATE OF THE ART

[0002] A wafer is the silicon crystal chip used to manufacture integrated semiconductor circuits from silicon. Its round shape gives it the name "wafer." Wafer manufacturing involves a process in which both sides of the wafer are polished and ground. Many technologies exist for polishing and grinding wafers. In the modern semiconductor industry, the chemical-mechanical polishing and grinding (CMP) process is commonly used. This process smooths the etched surface of the wafer to a nanometer-scale smoothness, while simultaneously addressing the warping and flatness of the silicon chip to avoid problems encountered during micro-etching lithography when using the silicon chip in high-end applications. Therefore, wafer polishing and grinding is a crucial step in the semiconductor manufacturing process.

[0003] DE 10 2021 209 172 A1 discloses a processing device. The processing device comprises: a first cassette stage to which a first cassette is attached, holding several wafers; a second cassette stage to which a second cassette is attached, holding several wafers; a clamping table having a holding surface that holds the wafer on the holding surface; a processing unit that processes the wafer; a feeding mechanism that transports the wafer to the holding surface of the clamping table; and a conveying mechanism that removes the wafer from the holding surface of the clamping table.a setting section that sets first processing conditions used at the time of processing the wafer held in the first cassette mounted on the first cassette stage, and second processing conditions that differ from the first processing conditions and are used at the time of processing the wafer held in the second cassette mounted on the second cassette stage; a selection section that selects the first cassette stage or the second cassette stage;a conveying control section which, when the processing of all wafers held in a cassette mounted on one cassette stage is completed according to the processing conditions corresponding to the cassette stage selected by the selection section, and the last wafer has been conveyed from the holding surface, thereby releasing the holding surface, immediately conveys the wafer held in a cassette mounted on the other cassette stage onto the holding surface; and a switching section which, when the wafer to be placed on the holding surface is switched from the wafer conveyed from the side of one cassette stage to the wafer conveyed from the side of the other cassette stage, switches the processing conditions to those corresponding to the other cassette stage.

[0004] For a double-sided processing unit, the wafer must be inserted into the recesses of a carrier during polishing and grinding. According to current technology, this step is performed manually, resulting in low production efficiency, a high workload for operators, and a potential impairment of wafer quality. CONTENT OF THE PRESENT INVENTION

[0005] The object of the present invention is to provide a system and method for polishing and grinding wafers in order to solve the above-mentioned problems of the prior art, to increase the efficiency of wafer polishing and grinding, to ensure the quality of wafer processing and at the same time to reduce the workload of the operators.

[0006] The problem is solved by the following solutions of the present invention: The present invention provides a system for polishing and grinding wafers, comprising a frame and a loading unit, a transfer unit, a processing unit, and a pickup unit arranged on the frame.

[0007] The loading unit is capable of storing several stacked wafers.

[0008] The transfer unit is capable of carrying and positioning individual wafers.

[0009] The processing unit is capable of polishing and grinding wafers.

[0010] The picking unit comprises a robot arm and a robot hand, wherein the robot arm is arranged on the frame, the robot hand is connected to the robot arm, and the robot arm is capable of driving the robot hand to movement in space; the robot hand comprises a first picking section and a second picking section, wherein the first picking section has a flat structure for picking up wafers stored in the loading unit and is also capable of picking up wafers to be positioned in the transfer unit; wherein the second picking section comprises multiple picking heads for picking up wafers positioned in the transfer unit and for placing several of the picked wafers into processing stations of the processing unit, and after completion of wafer processing, the second picking section is also capable of removing the processed wafers.

[0011] Preferably, the first picking section comprises an outer clamping plate and an inner clamping plate, wherein both the outer clamping plate and the inner clamping plate have a clamping groove adapted to the wafer, wherein the clamping grooves of the outer clamping plate and the inner clamping plate are opposite each other, the inner clamping plate is slidably connected to the outer clamping plate, the inner clamping plate is connected to a clamping drive, and the outer clamping plate is a V-shaped plate whose opening is directed away from the inner clamping plate.

[0012] Preferably, the first pickup section has a Y-shaped plate structure, and the first pickup section is provided with several suction elements for picking up wafers, the suction elements being connected to an external suction drive.

[0013] Preferably, the second pickup section comprises a mounting base, wherein both the mounting base and the first pickup section are connected to the robot arm, the pickup heads are connected to the mounting base, several suction cups are arranged on the pickup heads, the suction cups being connected to an external suction drive, and the ends of the mounting base connected to the pickup heads are arranged at an angle.

[0014] Preferably, the mounting base has a star structure, and the mounting base comprises several support plates, wherein the pick-up heads are connected to the support plates in a one-to-one correspondence.

[0015] Preferably, the transfer unit comprises a positioning device, wherein the positioning device is arranged on the frame, and the positioning device comprises a turning station, positioning stations and storage stations, wherein the turning station is able to hold wafers and drive them to turn.

[0016] The number of positioning stations is multiple, each positioning station includes positioning pins arranged evenly in a circle, and a detection sensor is also arranged at the positioning station to detect whether the positioning station is carrying a wafer and whether the wafer is tilted or displaced, and the second pick-up section is able to pick up the wafers from the positioning stations.

[0017] The storage stations are arranged below the positioning stations, with each station corresponding to the other. The storage stations are designed to store wafers to be positioned, and the first pickup section is able to pick up the wafers from the storage stations.

[0018] Preferably, the transfer unit also includes a buffer device, wherein the buffer device comprises a buffer base, a motion device and a buffer table, wherein the buffer base is arranged on the frame, the buffer table is connected to the buffer base via the motion device, and the motion device is able to drive the buffer table to a movement in a three-dimensional space.

[0019] The buffer table has buffer stations, each comprising a buffer fork arm and a buffer positioning block, the buffer fork arm having a flat structure, the buffer positioning block being slidably connected to the buffer fork arm, the buffer positioning block being connected to a buffer drive, both the buffer fork arm and the buffer positioning block having a buffer positioning groove adapted to the wafers, each of the buffer positioning grooves being U-shaped, the openings of the buffer positioning grooves of the buffer fork arm and the buffer positioning block being opposite each other, several of the buffer positioning grooves working together to fix the wafers, and the buffer stations and the storage stations being assigned one-to-one such that the buffer stations hold the wafers of the storage stations and move them to the positioning stations.

[0020] Preferably, the system for polishing and grinding wafers further comprises an unloading unit and an unloading docking unit, wherein the unloading unit is able to remove the wafers processed in the processing unit and transfer them to the unloading docking unit.

[0021] The unloading docking unit comprises a buffer basin and an unloading basin, wherein the buffer basin is located near the processing unit, the unloading unit is able to remove the wafers from the processing unit and transport them to the buffer basin, the unloading unit is also able to transfer the wafers from the buffer basin to the unloading basin, and the unloading basin can be transported to subsequent processing processes.

[0022] Preferably, the system for polishing and grinding wafers comprises a control unit, wherein the loading unit, the transfer unit, the processing unit and the pickup unit are in communication connection with the control unit.

[0023] The processing unit also includes a visual positioning device, which is capable of collecting the position information of the processing stations.

[0024] The present invention provides a method for polishing and grinding wafers, in which the above-described system for polishing and grinding wafers is used, wherein the first pick-up section of the pick-up unit picks up the wafers from the loading unit and the robot arm drives the robot hand to a movement in order to place the wafers on the transfer unit; the transfer unit positions the wafers, several of the pickup heads of the second pickup section pick up several of the wafers positioned in the transfer unit, the robot arm drives the robot hand to a movement in order to transfer the wafers to processing stations of the processing unit; The processing unit performs polishing and grinding operations on the wafers.

[0025] The present invention achieves the following technical effects compared to the prior art: The system according to the invention for polishing and grinding wafers comprises a frame and a loading unit, a transfer unit, a processing unit, and a pick-up unit, which are arranged on the frame, wherein the loading unit is capable of storing several stacked wafers; wherein the transfer unit is capable of carrying and positioning individual wafers; wherein the processing unit is capable of polishing and grinding wafers; wherein the pick-up unit comprises a robot arm and a robot hand, wherein the robot arm is arranged on the frame, the robot hand is connected to the robot arm, and the robot arm is capable of driving the robot hand to a movement in a space;The robot hand comprises a first pick-up section and a second pick-up section, wherein the first pick-up section has a flat structure for picking up wafers stored in the loading unit, and the first pick-up section is also capable of picking up wafers to be positioned in the transfer unit; wherein the second pick-up section comprises multiple pick-up heads for picking up wafers positioned in the transfer unit and for placing several of the picked-up wafers into processing stations of the processing unit, and after completion of wafer processing, the second pick-up section is also capable of removing the processed wafers.

[0026] During operation of the system according to the invention for polishing and grinding wafers, the first pickup section of the pickup unit picks up wafers from the loading unit. The robot arm drives the robot hand to move the wafers to the transfer unit. The transfer unit positions the wafers, and several pickup heads of the second pickup section pick up several of the wafers positioned in the transfer unit. The robot arm drives the robot hand to move the wafers to the processing stations of the processing unit. The processing unit performs polishing and grinding operations on the wafers. The robot arm according to the invention comprises a first and a second pickup section, enabling the robot arm to pick up wafers from both the loading unit and the transfer unit, thereby increasing pickup efficiency.The second pick-up section comprises multiple pick-up heads capable of simultaneously collecting several wafers. Working in conjunction with the robot arm, these heads transfer the wafers to the processing stations of the processing unit, enabling the simultaneous loading of multiple stations and increasing production efficiency. The combination of the robot arm and robot hand for material pick-up effectively prevents wafer damage and improves wafer quality.

[0027] The present invention also presents a method for polishing and grinding wafers, in which the above-described system for polishing and grinding wafers is used to increase production efficiency, ensure the quality of wafer processing and reduce the workload of the operators. BRIEF DESCRIPTION OF THE DRAWING

[0028] In order to illustrate the technical solution of the embodiments of the present invention or in the prior art more clearly, the accompanying drawings, which are necessary for the description of the embodiments, are briefly presented below. Fig. Figure 1 shows a schematic representation of the structure of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 2 shows a schematic representation of the internal structure of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 3 shows a schematic representation of the structure of a robot hand of a system for polishing and grinding wafers, as disclosed in embodiment I of the present invention; Fig. Figure 4 shows a schematic representation of the structure of a robot hand of a system for polishing and grinding wafers, as disclosed in embodiment II of the present invention; Fig. Figure 5 shows a schematic representation of the structure of a turning station of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 6 shows a schematic representation of the structure of a positioning device of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 7 shows an axonometric view of a buffer device of a system for polishing and grinding wafers, disclosed by embodiments of the present invention; Fig. Figure 8 shows a schematic representation of the main view of a buffer device of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 9 shows a schematic representation of the side view of a buffer device of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention; Fig. Figure 10 shows a schematic representation of the top view of a buffer device of a system for polishing and grinding wafers, which is disclosed by embodiments of the present invention. Reference symbol list: 1. Frame; 2, loading unit; 3, transfer unit; 301, Positioning device; 302, turning station; 303, Positioning station; 304, storage station; 305, buffer device; 306, buffer base; 307, Movement device; 308, buffer table; 309, buffer fork arm; 310, Buffer positioning block; 311, buffer positioning groove; 4, processing unit; 401, visual positioning device; 5, Collection unit; 501, first pickup section; 502, second pickup section; 503, Pickup point; 504, outer clamping plate; 505, inner clamping plate; 506, clamping groove; 507, Mounting base; 508, suction cup; 509, support plate; 510, suction element; 511, clamping drive 6, discharge unit; 7, Unloading docking unit; 701, buffer basin; 702, unloading basin. DETAILED DESCRIPTION

[0029] The technical solution of the embodiments of the present invention is described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0030] The object of the present invention is to provide a system and method for polishing and grinding wafers in order to solve the above-mentioned problems of the prior art, to increase the efficiency of wafer polishing and grinding, to ensure the quality of wafer processing and at the same time to reduce the workload of the operators.

[0031] In order to make the object, features and advantages of the present invention more obvious and understandable, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Example I

[0032] This embodiment provides a system for polishing and grinding wafers, comprising a rack 1 and a loading unit 2, a transfer unit 3, a processing unit 4, and a pick-up unit 5, which are arranged on the rack 1, wherein the loading unit 2 is capable of storing several stacked wafers; wherein the transfer unit 3 is capable of carrying and positioning individual wafers; wherein the processing unit 4 is capable of polishing and grinding wafers; wherein the pick-up unit 5 comprises a robot arm and a robot hand, wherein the robot arm is arranged on the rack 1, the robot hand is connected to the robot arm, and the robot arm is capable of driving the robot hand to a movement in a space;The robot hand comprises a first pick-up section 501 and a second pick-up section 502, wherein the first pick-up section 501 has a flat structure for picking up wafers stored in the loading unit 2, and the first pick-up section 501 is also capable of picking up wafers to be positioned in the transfer unit 3; wherein the second pick-up section 502 comprises several pick-up heads 503 for picking up wafers positioned in the transfer unit 3 and for placing several of the picked-up wafers into processing stations of the processing unit 4, and after completion of wafer processing, the second pick-up section 502 is also capable of removing the processed wafers.

[0033] In the operation of the system according to the invention for polishing and grinding wafers, the first pick-up section 501 of the pick-up unit 5 picks up wafers from the loading unit 2. The robot arm drives the robot hand to move the wafers to the transfer unit 3. The transfer unit 3 positions the wafers, and several of the pick-up heads 503 of the second pick-up section 502 pick up several of the wafers positioned in the transfer unit 3. The robot arm drives the robot hand to move the wafers to the processing stations of the processing unit 4. The processing unit 4 performs polishing and grinding operations on the wafers. The robot arm according to the invention comprises a first pick-up section 501 and a second pick-up section 502, enabling the robot arm to pick up wafers from the loading unit 2 and the transfer unit 3 and increasing the efficiency of the picking process.The second pick-up section 502 comprises several pick-up heads 503, which can pick up multiple wafers simultaneously and, in cooperation with the robot arm, transfer the wafers to the processing stations of processing unit 4. This enables the simultaneous loading of multiple processing stations of processing unit 4 and increases production efficiency. The combination of the robot arm and the robot hand for material pick-up effectively prevents damage to the wafers and improves wafer quality.

[0034] In this specific embodiment, the first pick-up section 501 comprises an outer clamping plate 504 and an inner clamping plate 505, wherein both the outer clamping plate 504 and the inner clamping plate 505 have a clamping groove 506 adapted to the wafer, wherein the clamping grooves 506 of the outer clamping plate 504 and the inner clamping plate 505 are opposite each other, the inner clamping plate 505 is slidably connected to the outer clamping plate 504, the inner clamping plate 505 is connected to a clamping drive 511, and the outer clamping plate 504 is a V-shaped plate whose opening is directed away from the inner clamping plate 505. The clamping drive 511 drives the inner clamping plate 505 to slide and adjusts the distance between the outer clamping plate 504 and the inner clamping plate 505 so that the opposing clamping grooves 506 of the outer clamping plate 504 and the inner clamping plate 505 can hold the wafers in order to pick up the wafers.The outer clamping plate 504 has a plate-like structure, allowing it to be inserted into the gap between adjacent wafers of the loading unit 2 for smooth wafer pick-up. The outer clamping plate 504 is V-shaped and can be provided with a clamping groove 506 at each end of the opening of the V-shaped outer clamping plate 504 to hold the wafers in place at multiple points and increase pick-up reliability. In practice, the clamping drive 511 can be implemented as a hydraulic or pneumatic cylinder.

[0035] In particular, the second pick-up section 502 includes an assembly base 507, wherein both the assembly base 507 and the first pick-up section 501 are connected to the robot arm. The pick-up heads 503 are connected to the assembly base 507, and several suction cups 508 are arranged on each of the pick-up heads 503, employing a multi-point suction method to enable more secure wafer picking. The suction cups 508 are connected to an external suction drive that can evacuate and vent the suction cups 508. During evacuation, the suction cups 508 pick up the wafers. When the wafers need to be placed at the processing stations of the processing unit 4, the suction drive vents the suction cups 508 to detach them from the wafers.In this specific embodiment, the pick-up heads 503 are connected to the underside of the mounting base 507, and the suction cups 508 are also arranged on the underside of the pick-up heads 503 to ensure that the wafers can be picked up and released smoothly. To avoid interference, the ends of the mounting base 507 that are connected to the pick-up heads 503 are angled to provide the pick-up heads 503 with sufficient working space and to improve the operational reliability of the robot hand.

[0036] In particular, the mounting base 507 has a star-shaped structure, comprises several support plates 509, and the pick-up heads 503 are connected to the support plates 509 in a one-to-one correspondence, which helps to improve the uniformity of the load on the mounting base 507 and increase the motion stability of the robot hand. In this specific embodiment, the mounting base 507 comprises three support plates 509, and the number of pick-up heads 503 is also three. Accordingly, the number of processing stations on each carrier of the processing unit 4 is also three, in order to meet the loading requirements during processing and thus effectively increase processing efficiency.In practical application, the number of pickup heads 503 can be adjusted depending on the number of processing stations of the carrier of the processing unit 4 in order to adapt to different processing conditions and improve the flexible adaptability of the system.

[0037] The transfer unit 3 comprises a positioning device 301, wherein the positioning device 301 is arranged on the frame 1, and the positioning device 301 comprises a turning station 302, positioning stations 303 and storage stations 304, wherein the turning station 302 is able to hold wafers and drive them to a turning, whereby the wafers are turned by 180° to meet various processing requirements.

[0038] The number of positioning stations 303 is multiple to meet the loading requirements of the processing stations of each carrier in processing unit 4. Each positioning station 303 includes positioning pins arranged evenly in a circle. A detection sensor is also located at each positioning station 303 to detect whether the station is carrying a wafer and whether the wafer is tilted or displaced, thus enabling the wafer to be positioned correctly. The second pick-up section 502 is capable of picking up the wafers from the positioning stations 303. The pick-up heads 503 suction the wafers from the positioning stations 303 and transfer them to the processing stations of processing unit 4 under the guidance of the robot arm.

[0039] The positioning unit 301 is simultaneously equipped with storage stations 304. The storage stations 304 are arranged below the positioning stations 303, corresponding one-to-one. The storage stations 304 are configured to hold wafers to be positioned. The first pick-up section 501 is capable of picking up the wafers from the storage stations 304 and transferring and positioning them from the storage stations 304 to the positioning stations 303, thus facilitating subsequent wafer processing.

[0040] It should also be emphasized that the transfer unit 3 also includes a buffer device 305, wherein the buffer device 305 comprises a buffer base 306, a motion device 307 and a buffer table 308, wherein the buffer base 306 is arranged on the frame 1, the buffer table 308 is connected to the buffer base 306 via the motion device 307, and the motion device 307 is able to drive the buffer table 308 to a movement in a three-dimensional space and thus drive the wafers buffered on the buffer table 308 to a movement.

[0041] The buffer table 308 has buffer stations, each buffer station comprising a buffer fork arm 309 and a buffer positioning block 310, the buffer fork arm 309 having a flat structure, the buffer positioning block 310 being slidably connected to the buffer fork arm 309, the buffer positioning block 310 being connected to a buffer drive 312, both the buffer fork arm 309 and the buffer positioning block 310 having a buffer positioning groove 311 adapted to the wafers, each of the buffer positioning grooves 311 being U-shaped, the openings of the buffer positioning grooves 311 of the buffer fork arm 309 and the buffer positioning block 310 being opposite each other, several of the buffer positioning grooves 311 cooperating to fix the wafers.The buffer drive 312 is capable of driving the buffer positioning block 310 to a reciprocating motion in order to adjust the distance between the buffer positioning block 310 and the buffer fork arm 309, so that the buffer positioning grooves 311 of the buffer positioning block 310 and the buffer fork arm 309 can fix the wafers. In combination with the motion device 307, the wafers are driven into motion. In this particular embodiment, the buffer stations and the storage stations 304 are assigned one-to-one, so that the buffer table 308 holds the wafers of the storage stations 304 and moves them to the positioning stations 303 to facilitate wafer positioning. The buffer fork arm 309 has a flat structure so that it can be inserted into the gap between the wafers of the storage stations 304 to ensure the operational reliability of the buffer device 305.

[0042] Furthermore, the system according to the invention for polishing and grinding wafers also comprises an unloading unit 6 and an unloading docking unit 7, wherein the unloading unit 6 is capable of removing the wafers processed in the processing unit 4 and transferring them to the unloading docking unit 7. The unloading unit 6 can use an unloading robot to improve unloading efficiency and at the same time largely avoid damage to the wafers.

[0043] In this specific embodiment, the unloading docking unit 7 comprises a buffer basin 701 and an unloading basin 702, wherein the buffer basin 701 is arranged near the processing unit 4, the unloading unit 6 is capable of removing the wafers from the processing unit 4 and transporting them into the buffer basin 701, the unloading unit 6 is also capable of transferring the wafers from the buffer basin 701 into the unloading basin 702, and the unloading basin 702 can be transported to subsequent processing processes. The fact that the unloading docking unit 7 is equipped with the buffer basin 701 and the unloading basin 702 ensures the cleanliness and safety of the wafers, thus guaranteeing wafer quality.

[0044] Furthermore, the system according to the invention for polishing and grinding wafers comprises a control unit, wherein the loading unit 2, the transfer unit 3, the processing unit 4 and the pickup unit 5 are in communication connection with the control unit, which facilitates the control of the working state of each unit and improves the degree of automation of the system.

[0045] In addition, the processing unit 4 also includes a visual positioning device 401, wherein the visual positioning device 401 is able to collect the position information of the processing stations in order to monitor the information of the processing stations of the processing unit 4 and the feeding information of the wafers. Example II

[0046] In the wafer polishing and grinding system of this embodiment, the first pick-up section 501 has a Y-shaped plate structure. The first pick-up section 501 is equipped with several suction elements 510 for picking up wafers, the suction elements 510 being connected to an external suction drive. The suction drive is capable of evacuating or venting the suction elements 510. During evacuation, the suction elements 510 are able to draw in the wafers due to the negative pressure. When the wafers need to be released, the suction drive vents the suction elements 510 to separate them from the wafers. The first pick-up section 501 uses a suction method to pick up the wafers, which provides maximum protection for the wafers and increases safety during pick-up. It should be noted that the suction drive can be provided by external devices such as pumps or by an external compressed air source.This can be adjusted depending on the specific operating conditions to meet the requirements for vacuumed collection.

[0047] The other structures of the system for polishing and grinding wafers in this embodiment are identical to those in embodiment I and are not explained further here. Example III

[0048] This embodiment provides a method for polishing and grinding wafers, in which the system for polishing and grinding wafers of embodiment I or embodiment II is used, wherein the first pick-up section 501 of the pick-up unit 5 picks up the wafers from the loading unit 2 and the robot arm drives the robot hand to a movement in order to place the wafers on the transfer unit 3; The transfer unit 3 positions the wafers, several of the pickup heads 503 of the second pickup section 502 pick up several of the wafers positioned in the transfer unit 3, the

[0049] The robot arm drives the robot to a movement in order to transfer the wafers to processing stations of processing unit 4; The processing unit 4 performs polishing and grinding operations on the wafers.

[0050] In the inventive method for polishing and grinding wafers, the system for polishing and grinding wafers of embodiment I or embodiment II is used to increase production efficiency, ensure the quality of wafer processing and reduce the workload of the operators. Example IV

[0051] This embodiment provides a method for polishing and grinding wafers, in which the wafer polishing and grinding system of embodiment I or embodiment II is used. The method comprises, in particular, the following steps: S01: An AGV (Automated Guided Vehicle) places a full open cassette at loading unit 2. Loading unit 2 receives a read command from a PLC and reads the barcode information from the open cassette. This barcode information is then sent back to the PLC. The PLC receives the barcode information and forwards it to a higher-level MES (Manufacturing Execution System). At the PLC's request, the MES sends back to the PLC the information contained in the barcode about the wafers in each layer of the open cassette. Simultaneously, loading unit 2 scans the slots of each layer of the cassette into which the wafers are inserted and sends the scan results back to the PLC. The PLC compares the scan results with the information about the wafers in each layer of the open cassette that was sent back by the MES.In case of deviations, an alarm device triggers an alarm; in case of a match, the next step is carried out automatically. S02: The first pick-up section 501 of the pick-up unit 5 horizontally removes a wafer from the loading station 2. If the system requires a wafer to be turned, the pick-up unit 5 first transfers the wafer to the turning station 302 of the transfer unit 3 to turn the wafer 180°. The pick-up unit 5 then places the turned wafer into one of the storage stations 304 in the lower part of the positioning unit 301 (the positioning unit 301 consists of two parts: the upper positioning stations 303 and the lower storage stations 304, allowing multiple wafers to be buffered). If turning the wafer is not required, the first pick-up section 501 of the pick-up unit 5 places the wafer taken from the loading station 2 directly into one of the storage stations 304 in the lower part of the positioning unit 301. This process is repeated until a predetermined number of wafers has been picked up. S03: The buffer unit 305 moves three wafers simultaneously from the storage stations 304 in the lower part of the positioning unit 301 and places them at the positioning stations 303 of the positioning unit 301. The three positioning stations 303 of the positioning unit 301 simultaneously perform a mechanical positioning of the wafers, with the antistatic positioning pins pressing the outer edges of the wafers for positioning. S04: After processing unit 4 has completed polishing and grinding, unloading unit 6 removes the wafers from the wafer carrier recesses and places them in unloading docking unit 7. Unloading docking unit 7 consists of several height-adjustable units and an overflow tray. Once a wafer is placed in the unloading docking unit, one unit lowers, fully immersing the wafer in the water of the overflow tray to protect its surface (process requirements stipulate that the wafer must be immersed in deionized water as soon as possible after polishing and grinding). In this way, all wafers from the wafer carriers are placed in unloading docking unit 7 and fully immersed in the water. S05: Processing unit 4 then performs a self-cleaning process. After cleaning is complete, pickup unit 5 has already completed the second step described above. Steps six, seven, and eight are then repeated to complete the loading process. S06: The pick-up unit 5 removes three wafers from the positioning stations 303 in the upper part of the positioning device 301 and places them in the recesses of a wafer carrier of the processing unit 4 using the compensation data provided by the visual positioning device 401. Since the position of the wafer carrier has an error at each stop, the pick-up unit 5 must perform visual positioning in cooperation with the visual positioning device 401 in order to insert the wafers precisely into the recesses of the wafer carrier. S07: Processing unit 4 has several wafer carriers. A polishing pad is located below the wafer carriers, and a lower polishing wheel is located below the polishing pad. After a wafer carrier has been fully loaded with wafers, the lower polishing wheel of processing unit 4 rotates through a specific angle, causing another wafer carrier to rotate into the loading position. The sixth step is then repeated to load the current wafer carrier.Simultaneously, the unloading unit 6 presses the wafers into the wafer carrier, which has just completed the sixth step to remove water, and checks whether the wafers are fully inserted into the recesses. If the check reveals that a wafer is not properly positioned, it is repeatedly pressed with flexible material, and a size of the wafer indicating the degree of insertion into the groove is checked with a micrometer sensor. If the second check is also unsuccessful, the system issues an alarm message and awaits manual intervention. S08: Steps six and seven are repeated; all wafers are placed into the recesses of the wafer trays, and their correct placement is verified. Once loading is complete, a loading completion signal is sent from the PLC to processing unit 4, whereupon processing unit 4 begins polishing and grinding. S09: After the loading process is complete, processing unit 4 begins operation. Unloading unit 6 removes the wafers from buffer basin 701 of unloading docking unit 7 and places them in unloading basin 702. In this way, all wafers from unloading docking unit 7 are placed in unloading basin 702. A wafer cassette is located in unloading basin 702. As soon as the cassette is full, a full message is sent from the PLC to the MES system, which then sends an instruction to the AGV cart to remove the material.

Claims

[1] System for polishing and grinding wafers, comprising a frame (1) and a loading unit (2), a transfer unit (3), a processing unit (4), a pickup unit (5) arranged on the frame (1), wherein the loading unit (2) is able to store several stacked wafers; wherein the transfer unit (3) is able to carry and position individual wafers; wherein the processing unit (4) is capable of polishing and grinding wafers; wherein the pick-up unit (5) comprises a robot arm and a robot hand, the robot arm being arranged on the frame (1), the robot hand being connected to the robot arm, the robot arm being capable of driving the robot hand to a movement in space; the robot hand comprising a first pick-up section (501) and a second pick-up section (502), the first pick-up section (501) having a flat structure for picking up the wafers stored in the loading unit (2), and the first pick-up section (501) also being capable of picking up the wafers to be positioned in the transfer unit (3); the second pick-up section (502) comprising several pick-up heads (503) for picking up the wafers positioned in the transfer unit (3) and for placing several of the picked-up wafers into processing stations of the processing unit (4), and after completion of wafer processing, the second pick-up section (502) also being capable of removing the processed wafers. [2] System for polishing and grinding wafers according to claim 1, wherein the first pick-up section (501) comprises an outer clamping plate (504) and an inner clamping plate (505), wherein both the outer clamping plate (504) and the inner clamping plate (505) have a clamping groove (506) adapted to the wafer, wherein the clamping grooves (506) of the outer clamping plate (504) and the inner clamping plate (505) are opposite each other, the inner clamping plate (504) is slidably connected to the outer clamping plate (505), the inner clamping plate (504) is connected to a clamping drive (511), and the outer clamping plate (505) is a V-shaped plate, the opening of which is directed away from the inner clamping plate (505). [3] System for polishing and grinding wafers according to claim 1, wherein the first pickup section (501) has a Y-shaped plate structure, and the first pickup section (501) is provided with several suction elements (510) for suctioning wafers, wherein the suction elements (510) are connected to an external suction drive. [4] System for polishing and grinding wafers according to claim 2 or 3, wherein the second pick-up section (502) comprises a mounting base (507), wherein both the mounting base (507) and the first pick-up section (501) are connected to the robot arm, the pick-up heads (503) are connected to the mounting base (507), several suction cups (508) are arranged on the pick-up heads (503), the suction cups (508) being connected to an external suction drive, and the ends of the mounting base (507) that are connected to the pick-up heads (503) are arranged at an angle. [5] System for polishing and grinding wafers according to claim 4, wherein the mounting base (507) has a star structure and the mounting base comprises several support plates (509), wherein the pick-up heads are connected to the support plates (509) in a one-to-one correspondence. [6] System for polishing and grinding wafers according to claim 1, wherein the transfer unit (3) comprises a positioning device (301), wherein the positioning device (301) is arranged on the frame (1), and the positioning device (301) comprises a turning station (302), positioning stations (304) and storage stations (305), wherein the turning station (302) is able to hold wafers and drive them to be turned; the number of positioning stations (303) is multiple, each of the positioning stations (303) includes positioning pins that are evenly arranged in a circle, and a detection sensor is also arranged at the positioning station (303) to detect whether the positioning station (303) is carrying a wafer and whether the wafer is tilted or displaced, and the second pick-up section (502) is able to pick up the wafers from the positioning stations (303); the storage stations (304) are arranged below the positioning stations (303), being assigned one to one, the storage stations (304) are set up to store wafers to be positioned, and the first pick-up section (501) is able to pick up the wafers from the storage stations (304). [7] System for polishing and grinding wafers according to claim 6, wherein the transfer unit (3) further comprises a buffer device (305), wherein the buffer device (305) comprises a buffer base (306), a motion device (307) and a buffer table (308), wherein the buffer base (306) is arranged on the frame (1), the buffer table (308) is connected to the buffer base (306) via the motion device (307), and the motion device (307) is able to drive the buffer table (308) to a movement in a three-dimensional space; the buffer table (308) has buffer stations, wherein the buffer stations (308) each comprise a buffer fork arm (309) and a buffer positioning block (310), wherein the buffer fork arm (309) has a flat structure, the buffer positioning block (310) is slidably connected to the buffer fork arm (309), and the buffer positioning block (310) is connected to a buffer drive (312).Both the buffer fork arm (309) and the buffer positioning block (310) have a buffer positioning groove (311) adapted to the wafers, each of the buffer positioning grooves (311) being U-shaped, the openings of the buffer positioning grooves (311) of the buffer fork arm (309) and the buffer positioning block (310) being opposite each other, several of the buffer positioning grooves (311) cooperating to fix the wafers, and the buffer stations (308) and the storage stations (304) being assigned one-to-one, such that the buffer stations hold the wafers of the storage stations (304) and move them to the positioning stations (303). [8] System for polishing and grinding wafers according to claim 1, further comprising a discharge unit (6) and a discharge docking unit (7), wherein the discharge unit (6) is able to remove the wafers processed in the processing unit (4) and transfer them to the discharge docking unit (7); the discharge docking unit (7) comprises a buffer basin (701) and a discharge basin (702), wherein the buffer basin (701) is arranged near the processing unit (4), the discharge unit (6) is able to remove the wafers from the processing unit (4) and transport them into the buffer basin (701), the discharge unit (6) is also able to transfer the wafers from the buffer basin (701) into the discharge basin (702), and the discharge basin (702) can be transported to subsequent processing processes. [9] System for polishing and grinding wafers according to claim 1, comprising a control unit, wherein the loading unit (2), the transfer unit (3), the processing unit (4) and the pickup unit (5) are in communication connection with the control unit; the processing unit (4) further comprising a visual positioning device (401), wherein the visual positioning device (401) is able to collect the position information of the processing stations. [10] Method for polishing and grinding wafers, wherein the system for polishing and grinding wafers according to any one of claims 1 to 9 is used, wherein the first pick-up section (501) of the pick-up unit picks up the wafers from the loading unit (2) and the robot arm drives the robot hand to a movement in order to place the wafers on the transfer unit (3); the transfer unit (3) positions the wafers, several of the pick-up heads (503) of the second pick-up section (502) pick up several of the wafers positioned in the transfer unit, the robot arm drives the robot to a movement to transfer the wafers to processing stations of the processing unit (4); the processing unit (4) performs polishing and grinding operations on the wafers.

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