SYSTEM AND METHOD FOR WAFER POLISHING AND GRINDING

Description

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims the benefit and priority of Chinese Patent Application No. 2024111972481 filed with the China National Intellectual Property Administration on Aug. 29, 2024, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

TECHNICAL FIELD

The present disclosure relates to the technical field of wafer production devices and peripheral supporting facilities, in particular to a system and a method for wafer polishing and grinding.

BACKGROUND

Wafer refers to silicon wafer used in the production of silicon semiconductor integrated circuits, which is called wafer due to its circular shape. In the production process of the wafer, there is a process of polishing and grinding both sides of the wafer. There are numerous technologies for polishing and grinding the wafer. The polishing and grinding method commonly used in the modern semiconductor industry is chemical-mechanical polishing and grinding (CMP). By using chemical-mechanical grinding, the etched surface of the wafer is flattened to nanometer smoothness, which takes into account the warpage, flatness and other indexes of the silicon wafer, and prevent the silicon wafer from encountering problems in the lithography etching process in high-end applications. Therefore, wafer polishing and grinding is an important part of the semiconductor processing technology.

For the double-sided processing unit, it is necessary to put the wafer into the groove of a carrier when polishing and grinding the wafer. In the prior art, this procedure is done manually, which leads to low production efficiency, high labor intensity of operators, and easy influence on the quality of the wafer.

SUMMARY

An objective of the present disclosure is to provide a system and a method for wafer polishing and grinding to solve the problems in the prior art. The efficiency of wafer polishing and grinding is improved, the processing quality of the wafer is guaranteed, and the labor intensity of operators is reduced at the same time.

To achieve the objective above, the present disclosure provides the following technical solution.

A system for wafer polishing and grinding includes a rack, and a loading unit, a transfer unit, a processing unit and a pickup unit which are arranged on the rack.

The loading unit is configured to store multiple wafers which are stacked.

The transfer unit is configured to carry and position a single wafer of the wafers.

The processing unit is configured to polish and grind the wafers.

The pickup unit includes a mechanical arm, and a manipulator. The mechanical arm is arranged on the rack and the manipulator is connected to the mechanical arm, and the mechanical arm is capable of driving the manipulator to move in a space. The manipulator includes a first pickup portion, and a second pickup portion. The first pickup portion is of a flat structure to pick up a wafer stored by the loading unit, and the first pickup portion is capable of picking up the wafers to be positioned in the transfer unit. The second pickup portion includes multiple pickup heads to pick up the wafers positioned by the transfer unit and to place the multiple wafers picked up by the pickup heads into processing positions of the processing unit. After a processing of the wafers is completed, the second pickup portion is capable of taking out the processed wafers.

Preferably, the first pickup portion includes an outer clamping plate, and an inner clamping plate. Each of the outer clamping plate and the inner clamping plate has clamping grooves in fit with the wafers, and the clamping grooves of the outer clamping plate are arranged opposite to the clamping grooves of the inner clamping plate. The inner clamping plate is slidably connected to the outer clamping plate and a clamping driver is connected to the inner clamping plate. The outer clamping plate is a V-shaped plate with an opening facing away from the inner clamping plate.

Preferably, the first pickup portion is of a Y-shaped plate structure, and multiple adhering elements are arranged on the first pickup portion to adhere the wafers. The adhering elements communicate with an external adhering driver.

Preferably, the second pickup portion includes a mounting substrate. The mounting substrate and the first pickup portion are both connected to the mechanical arm, and the pickup heads are connected to the mounting substrate. Multiple suction cups are arranged on each of the pickup heads, and the suction cups communicate with the external adhering driver. An end of the mounting substrate, connected to the pickup heads, is obliquely arranged.

Preferably, the mounting substrate is of a star structure, and includes multiple branch plates; and the pickup heads are connected to the branch plates in a one-to-one correspondence.

Preferably, the transfer unit includes a positioning mechanism, the positioning mechanism is arranged on the rack, and includes a flipping station, multiple positioning stations, and storage stations. The flipping station is capable of fixing the wafer and driving the wafer to flip.

Each of the multiple positioning stations includes positioning pins uniformly distributed in a circumference, and detection sensors are further arranged on the positioning stations to detect whether the wafers are carried on the positioning stations and whether the wafers are inclined or deviated or not. The second pickup portion is capable of picking up the wafers on the positioning stations.

The storage stations are arranged below the positioning stations in a one-to-one correspondence. The storage stations are configured to store the wafers to be positioned, and the first pickup portion is capable of picking up the wafers on the storage stations.

Preferably, the transfer unit further includes a buffer mechanism that includes a buffer seat, a motion mechanism, and a buffer table. The buffer seat is arranged on the rack. The buffer table is connected to the buffer seat through the motion mechanism, and the motion mechanism is configured to drive the buffer table to move in a three-dimensional space.

The buffer table includes buffer stations, each of the buffer stations includes a buffer yoke, and a buffer positioning block. The buffer yoke is of a flat structure, the buffer positioning block is slidably connected to the buffer yoke, and a buffer driver is connected to the buffer positioning block; each of the buffer yoke and the buffer positioning block has buffer positioning slots in fit with the wafers. Each of the buffer positioning slots is U-shaped, and openings of the buffer positioning slots of the buffer yoke are arranged opposite to openings of the buffer positioning slots of the buffer positioning block. The buffer positioning slots of the buffer yoke and the buffer positioning slots of the buffer yoke cooperate to fix the wafers. The buffer stations and the storage stations are in a one-to-one correspondence to enable the buffer table to fix the wafers at the storage stations and drive the wafers to move to the positioning stations.

Preferably, the system for wafer polishing and grinding further includes an unloading unit, and an unloading docking unit, where the unloading unit is configured to take out the wafers processed in the processing unit, and transfer the wafers to the unloading docking unit.

The unloading docking unit includes a buffer water tank, and an unloading water tank. The buffer water tank is arranged adjacent to the processing unit and the unloading unit is capable of taking out the wafers from the processing unit and conveying the wafers into the buffer water tank. The unloading unit is further capable of transferring the wafers in the buffer water tank into the unloading water tank, and the unloading water tank is capable of being conveyed to a subsequent processing procedure.

Preferably, the system for wafer polishing and grinding further including a control unit, where the loading unit, the transfer unit, the processing unit and the pickup unit are all in communication connection with the control unit.

The processing unit further includes a visual positioning mechanism, and the visual positioning mechanism is configured to collect position information of the processing positions.

The present disclosure provides a method for wafer polishing and grinding. The system for wafer polishing and grinding above is used, the method includes: picking up a wafer from the loading unit by the first pickup portion of the pickup unit, and driving the manipulator by the mechanical arm to move to place the wafer in the transfer unit;

• • positioning the wafer by the transfer unit, picking up the multiple wafers positioned by the transfer unit through the multiple pickup heads of the second pickup portion, and driving the manipulator by the mechanical arm to move to transfer the multiple wafers to the processing positions of the processing unit;
  • polishing and grinding the wafers through the processing unit.

Compared with the prior art, the present disclosure achieves the following technical effects: a system for wafer polishing and grinding provided by the present disclosure includes a rack, and a loading unit, a transfer unit, a processing unit and a pickup unit which are arranged on the rack. The loading unit can store multiple wafers which are stacked. The transfer unit can carry and position a single wafer. The processing unit can polish and grind the wafers. The pickup unit includes a mechanical arm, and a manipulator. The mechanical arm is arranged on the rack, the manipulator is connected to the mechanical arm, and the mechanical arm can drive the manipulator to move in a space. The manipulator includes a first pickup portion, and a second pickup portion. The first pickup portion is of a flat structure to pick up a wafer stored by the loading unit, and can pick up a wafer to be positioned in the transfer unit. The second pickup portion includes multiple pickup heads to pick up wafers positioned by the transfer unit and to place the multiple wafers which are picked up into processing positions of the processing unit. After the processing of the wafer is completed, the second pickup portion can take out the processed wafer.

When the system for wafer polishing and grinding provided by the present disclosure operates, the first pickup portion of the pickup unit picks up the wafer from the loading unit, and the manipulator is driven by the mechanical arm to move to place the wafer in the transfer unit. The wafer is positioned by the transfer unit. Multiple wafers positioned by the transfer unit are picked up by multiple pickup heads of the second pickup portion. The manipulator is driven by the mechanical arm to move, thus transferring the wafers to the processing positions of the processing unit. The wafers are polished and ground through the processing unit. The manipulator includes the first pickup portion, and the second pickup portion, such that the manipulator can pick up the wafer from the loading unit and the transfer unit, and the pickup efficiency is improved. The second pickup portion includes multiple pickup heads which can pick up multiple wafers simultaneously and cooperates with the mechanical arm to transfer the wafers to the processing positions of the processing unit, thus achieving simultaneous loading of the multiple processing positions of the processing unit, and improving the production efficiency. The combination of the mechanical arm and the manipulator is used to pick up the material, thus effectively avoiding wafer damage and improving the quality of the wafer.

A method for wafer polishing and grinding is further provided, which uses the system for wafer polishing and grinding above. The processing quality of the wafer is guaranteed while improving the production efficiency, and the labor burden of operators is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions of the embodiments of the present disclosure or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and those of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

FIG. 1 is a structural diagram of a system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 2 is a schematic diagram of an internal structure of the system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 3 is a structural diagram of a manipulator of the system for wafer polishing and grinding according to Embodiment 1 of the present disclosure;

FIG. 4 is a structural diagram of a manipulator of the system for wafer polishing and grinding according to Embodiment 2 of the present disclosure;

FIG. 5 is a structural diagram of a flipping station of the system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 6 is a structural schematic diagram of a positioning mechanism of the system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 7 is an axonometric diagram of a buffer mechanism of the system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 8 is a schematic front view of the buffer mechanism of the system for wafer polishing and grinding according to embodiments of the present disclosure;

FIG. 9 is a schematic side view of the buffer mechanism of the system for wafer polishing and grinding according to embodiments of the present disclosure; and

FIG. 10 is a schematic top view of the buffer mechanism of the system for wafer polishing and grinding according to embodiments of the present disclosure.

In the drawings: 1 rack;

• • 2 loading unit;
  • 3 transfer unit; 301 positioning mechanism; 302 flipping station; 303 positioning station; 304 storage station; 305 buffer mechanism; 306 buffer seat; 307 motion mechanism; 308 buffer table; 309 buffer yoke; 310 buffer positioning block; 311 buffer positioning slot; 312 buffer driver;
  • 4 processing unit; 401 visual positioning mechanism;
  • 5 pickup unit; 501 first pickup portion; 502 second pickup portion; 503 pickup head; 504 outer clamping plate; 505 inner clamping plate; 506 clamping groove; 507 mounting substrate; 508 suction cup; 509 branch plate; 510 adsorption element; 511 clamping driver;
  • 6 unloading unit;
  • 7 unloading docking unit; 701 buffer water tank; 702 unloading water tank.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

An objective of the present disclosure is to provide a system and a method for wafer polishing and grinding to solve the problems in the prior art. The efficiency of wafer polishing and grinding is improved, the processing quality of the wafer is guaranteed, and the labor intensity of operators is reduced at the same time.

In order to make the objective, features and advantages of the present disclosure more clearly, the present disclosure is further described in detail below with reference to the accompanying drawings and embodiments.

Embodiment 1

This embodiment provides a system for wafer polishing and grinding, including a rack 1, and a loading unit 2, a transfer unit 3, a processing unit 4 and a pickup unit 5 which are arranged on the rack 1. The loading unit 2 is configured to store multiple wafers which are stacked. The transfer unit 3 is configured to carry and position a single wafer. The processing unit 4 is configured to polish and grind the wafers. The pickup unit 5 includes a mechanical arm, and a manipulator. The mechanical arm is arranged on the rack 1, the manipulator is connected to the mechanical arm, and the mechanical arm can drive the manipulator to move in a space. The manipulator includes a first pickup portion 501, and a second pickup portion 502. The first pickup portion 501 is of a flat structure to pick up a wafer stored by the loading unit 2, and can pick up a wafer to be positioned in the transfer unit 3. The second pickup portion 502 includes multiple pickup heads 503 to pick up the wafers positioned by the transfer unit 3 and to place the multiple wafers which are picked up into processing positions of the processing unit 4. After the processing of the wafers is completed, the second pickup portion 502 can take out the processed wafer.

When the system for wafer polishing and grinding provided by the present disclosure operates, the first pickup portion 501 of the pickup unit 5 picks up the wafer from the loading unit, and the manipulator is driven by the mechanical arm to move to place the wafer in the transfer unit 3. The wafer is positioned by the transfer unit 3. Multiple wafers positioned by the transfer unit 3 are picked up by multiple pickup heads 503 of the second pickup portion 502. The manipulator is driven by the mechanical arm to move, thus transferring the wafers to the processing positions of the processing unit 4. The wafers are polished and ground through the processing unit 4. The manipulator includes the first pickup portion 501, and the second pickup portion 502, such that the manipulator can pick up the wafer from the loading unit 2 and the transfer unit 3, and the pickup efficiency is improved. The second pickup portion 502 includes multiple pickup heads 503 which can pick up multiple wafers simultaneously, and cooperates with the mechanical arm to transfer the wafers to the processing positions of the processing unit 4, thus achieving simultaneous loading of the multiple processing positions of the processing unit 4, and improving the production efficiency. The combination of the mechanical arm and the manipulator is used to pick up the material, thus effectively avoiding wafer damage and improving the quality of the wafer.

In this specific embodiment, the first pickup portion 501 includes an outer clamping plate 504, and an inner clamping plate 505. Each of the outer clamping plate 504 and the inner clamping plate 505 has clamping grooves 506 in fit with the wafer, and the clamping grooves 506 of the outer clamping plate 504 are arranged opposite to the clamping grooves of the inner clamping plate 505. The inner clamping plate 505 is slidably connected to the outer clamping plate 504, a clamping driver 511 is connected to the inner clamping plate 505, and the outer clamping plate 504 is a V-shaped plate with an opening facing away from the inner clamping plate 505. The clamping driver 511 drives the inner clamping plate 505 to slide to adjust the distance between the outer clamping plate 504 and the inner clamping plate 505, such that the opposite clamping grooves 506 on the outer clamping plate 504 and the inner clamping plate 505 can fix the wafer to achieve the purpose of picking up the wafer. The outer clamping plate 504 is of a plate structure, which can extend into a gap between adjacent wafers in the loading unit 2 to pick up the wafer smoothly. The outer clamping plate 504 is V-shaped, clamping grooves 506 can be arranged at both ends of an opening of the V-shaped outer clamping plate 504 to fix the wafer at multiple points, thus improving the reliability of pickup. In actual application, the clamping driver 511 may use a hydraulic cylinder, or a pneumatic cylinder.

Specifically, the second pickup portion 502 includes a mounting substrate 507. The mounting substrate 507 and the first pickup portion 501 are both connected to the mechanical arm. The pickup heads 503 are connected to the mounting substrate 507. Multiple suction cups 508 are arranged on each pickup head 503 to enhance the adsorption and fixation effect on the wafer by multi-point adsorption. The suction cups 508 communicate with an external adhering driver. The external adhering driver can deflate and inflate the suction cup 508. When the suction cup 508 is deflated, the suction cup 508 adheres the wafer. When the wafer needs to be placed on the processing position of the processing unit 4, the adhering driver inflates the suction cup 508 to separate the suction cup from the wafer. In this specific embodiment, the pickup heads 503 are connected to the bottom of the mounting substrate 507, the suction cups 508 is also arranged at the bottom of the pickup head 503 to ensure smooth pickup and release of the wafer. In order to avoid interference, an end, connected to the pickup heads 503, of the mounting substrate 507 is arranged obliquely to reserve an enough operation space for the pickup heads 503, thus improving the operation reliability of the manipulator.

More specifically, the mounting substrate 507 is of a star structure. The mounting substrate 507 includes multiple branch plates 509, the pickup heads 503 are connected to the branch plates 509 in a one-to-one correspondence, which is conducive to improving the force-bearing uniformity of the mounting substrate 507 and improving the motion stability of the manipulator. In this specific embodiment, the mounting substrate 507 includes three branch plates 509, and the number of the pickup heads 503 is three. Correspondingly, the number of processing positions of each carrier of the processing unit 4 is also three, so as to meet the demands of processing and feeding, and effectively improve the processing efficiency. In actual application, the number of the pickup heads 503 can be adjusted according to the number of the processing positions of the carrier of the processing unit 4, thus adapting to different processing conditions, and improving the flexible adaptability of the system.

The transfer unit 3 includes a positioning mechanism 301. The positioning mechanism 301 is arranged on the rack 1, and includes a flipping station 302, positioning stations 303, and storage stations 304. The flipping station 302 can fix the wafer and drive the wafer to flip by 180°, so as to meet different processing demands.

Correspondingly, multiple positioning stations 303 are provided to adapt to the feeding demand of the processing position of each carrier of the processing unit 4. Each positioning station 303 includes positioning pins uniformly distributed in a circumference. The positioning station 303 is also provided with a detection sensor to detect whether the wafer is carried on the positioning station 303 and whether the wafer is inclined or deviated or not, thus achieving the positioning of the wafer. The second pickup portion 502 can pick up the wafer on the positioning station 303, and the pickup head 503 can adhere the wafer on the positioning station 303, and transfer the wafer to the processing position of the processing unit 4 under the driving of the mechanical arm.

The positioning mechanism 301 is also provided with storage stations 304. The storage stations 304 are arranged below the positioning stations 303 in a one-to-one correspondence. The storage station 304 is configured to store the wafers to be positioned. The first pickup portion 501 can pick up the wafer on the storage station 304 and transfer the wafer on the storage station 304 to the positioning station 303 for wafer positioning, thus providing convenience for the subsequent wafer processing.

It also should be emphasized that the transfer unit 3 further includes a buffer mechanism 305. The buffer mechanism 305 includes a buffer seat 306, a motion mechanism 307, and a buffer table 308. The buffer seat 306 is arranged on the rack 1, and the buffer table 308 is connected to the buffer seat 306 through the motion mechanism 307, and the motion mechanism 307 can drive the buffer table 308 to move in a three-dimensional space, thus driving the wafers buffered on the buffer table 308 to move.

The buffer table 308 includes buffer stations, each buffer station includes a buffer yoke 309, and a buffer positioning block 310. The buffer yoke 309 is of a flat structure, and the buffer positioning block 310 is slidably connected to the buffer yoke 309. A buffer driver 312 is connected to the buffer positioning block 310. Each of the buffer yoke 309 and the buffer positioning block 310 has buffer positioning slots 311 in fit with the wafer. The buffer positioning slot 311 is U-shaped, and openings of the buffer positioning slots 311 of the buffer yoke 309 are arranged opposite to openings of the buffer positioning slots 311 of the buffer positioning block 310. Multiple buffer positioning slots 311 cooperate to fix the wafers. The buffer driver 312 can drive the buffer positioning block 310 to reciprocate to adjust a spacing between the buffer positioning block 310 and the buffer yoke 309, such that the buffer positioning slots 311 on the buffer positioning block 310 and the buffer yoke 309 can fix the wafer, and drive the wafer to move in combination with the motion mechanism 307. In this specific embodiment, the buffer stations and the storage stations 304 are in a one-to-one correspondence, such that the buffer table 308 can fix the wafer at the storage station 304 and drive the wafer to move to the positioning station 303 to provide convenience for the positioning of the wafer. The buffer yoke 309 is of a flat structure, such that the buffer yoke 309 can extend into a gap between the wafers at the storage stations 304 to ensure the operation reliability of the buffer mechanism 305.

In addition, the system for wafer polishing and grinding further includes an unloading unit 6, and an unloading docking unit 7. The unloading unit 6 can take out the wafers processed in the processing unit 4, and transfer the wafers to the unloading docking unit 7. The unloading unit 6 may use an unloading robot, such that the unloading working efficiency is improved, and the wafers are prevented from being damaged to the greatest extent.

In this specific embodiment, the unloading docking unit 7 includes a buffer water tank 701, and an unloading water tank 702. The buffer water tank 701 is arranged adjacent to the processing unit 4, the unloading unit 6 can take out the wafers from the processing unit 4 and convey the wafers into the buffer water tank 701. The unloading unit 6 can further transfer the wafers in the buffer water tank 701 into the unloading water tank 702, and the unloading water tank 702 can be conveyed to the subsequent processing procedure. The unloading docking unit 7 is provided with the buffer water tank 701 and the unloading water tank 702, which is beneficial to keep the wafers clean and safe and ensure the quality of the wafers.

Further, the system for wafer polishing and grinding further includes a control unit. The loading unit 2, the transfer unit 3, the processing unit 4 and the pickup unit 5 are all in communication connection with the control unit, such that an operation state of each unit can be conveniently controlled, and the automation degree of the system is improved.

In addition to that, the processing unit 4 further includes a visual positioning mechanism 401. The visual positioning mechanism 401 can collect position information of the processing positions, so as to monitor the information at the processing position of the processing unit 4 and the loading information of the wafer.

Embodiment 2

In the system for wafer polishing and grinding of this embodiment, the first pickup portion 501 is of a Y-shaped plate structure, and multiple adhering elements 510 are arranged on the first pickup portion 501 to adhere the wafer, and the adhering elements 510 communicate with an external adhering driver. The adhering driver can deflate and inflate the adhering element 510. When the adhering element 510 is deflated, the adhering elements 51 can adhere the wafer under the action of the negative pressure. When the wafer needs to be released, the adhering driver can inflate the adhering elements 510 to make the adhering elements 510 separated from the wafer. The first pickup portion 501 picks up the wafer by adsorption, such that the wafer can be protected to the greatest extent, and the safety coefficient of pickup is improved. In addition, it also needs to be explained that the adhering driver may use an external air pump and other devices, or use an external compressed air source as the adhering driver, which can be adjusted according to specific working conditions to meet the adsorption and pickup demands.

Other structures of the system for wafer polishing and grinding in this embodiment are the same as those in Embodiment 1, and thus will not be described in detail here.

Embodiment 3

The present disclosure provides a method for wafer polishing and grinding. The system for wafer polishing and grinding in Embodiment 1 or Embodiment 2 is used, the wafer is picked up from the loading unit 2 through the first pickup portion 501 of the pickup unit 5, the manipulator is driven by the mechanical arm to move to place the wafer in the transfer unit 3.

The transfer unit 3 is used to position the wafer, multiple wafers positioned by the transfer unit 3 are picked up through multiple pickup heads 503 of the second pickup portion 502. The manipulator is driven by the mechanical arm to move to transfer the wafers to the processing positions of the processing unit 4.

The wafers are polished and ground through the processing unit 4.

The method for wafer polishing and grinding uses the system for wafer polishing and grinding of Embodiment 1 or Embodiment 2, the processing quality of the wafer can be guaranteed while improving the production efficiency, and the labor burden of operators is reduced.

Embodiment 4

This embodiment provides a method for wafer polishing and grinding, which uses the system for wafer polishing and grinding of Embodiment 1 or embodiment 2, and specifically includes the following steps.

• • S01. An Automatic Guided Vehicle (AGV) trolley puts an open material frame of a full Open Cassette into the loading unit 2, the loading unit 2 receives a code reading instruction sent by a Programmable Logic Controller (PLC), reads bar code information of the open material frame of the Open Cassette and feeds the bar code information back to the PLC. The PLC receives the bar code information and feeds the bar code information back to an upper Manufacturing Execution System (MES). The MES feeds back information of each layer of wafer in the material frame contained in the bar code to the PLC according to a request of the PLC, and meanwhile, the loading unit 2 scans each layer of Slot (a slot for placing the wafer) in the material frame, and feeds back a scanning result to the PLC. The PLC receives the scanning result and compares the scanning result with the information of each layer of wafer in the material frame fed back by the MES, and when there is a difference in comparison, an alarm device gives an alarm. If there is no difference in comparison, and the next step is automatically executed.
  • S02. The first pickup portion 501 of the pickup unit 5 is horizontally inserted into a gap between two adjacent wafers and picks up a wafer from the loading unit 2. When the system requires flipping, the pickup unit 5 first puts the wafer on the flipping station 302 of the transfer unit 3 to flip by 180 degrees, and then the pickup unit 5 puts the flipped wafer on the storage station 304 t at a lower portion of the positioning mechanism 301 (the positioning mechanism 301 is divided into two portions, the upper portion is the positioning stations 303, and the lower portion is the storage stations 304 capable of buffering multiple wafers). When the system does not require the wafer to be flipped, the first pickup portion 501 of the pickup unit 5 directly puts the wafer picked up from the loading unit 2 into the storage station 304 at the lower portion of the positioning mechanism 301 until the set number of wafers are buffered.
  • S03. The buffer mechanism 305 simultaneously transports three wafers from the storage stations 304 at the lower portion of the positioning mechanism 301 and places the wafers in the positioning stations 303 of the positioning mechanism 301. The three positioning stations 303 of the positioning mechanism 301 are used to mechanically position the wafers at the same time, and anti-static positioning pins are used to push the outer circle of each wafer for positioning.
  • S04. After the processing unit completes the polishing and grinding, the unloading unit 6 takes out the wafer from a groove of a wafer carrier and places the wafer into the unloading docking unit 7 which is composed of multiple lifting units and an overflow tank. After one wafer is placed in, there will be a lifting unit descending to make the wafer completely immersed in the water of the overflow tank to protect the surface of the wafer (the process requires that the polished and ground wafer should be immersed in deionized water as soon as possible after being taken out), such that all the wafers in the wafer carrier are placed into the unloading docking unit 7 and completely immersed in the water.
  • S05. Afterwards, the processing unit 4 has a self-cleaning process. After the cleaning is completed, the pickup unit 5 has completed S02 above, and then the following S06, S07 and S08 are repeated to complete the loading.
  • S06. The pickup unit 5 adheres three wafers from the positioning stations 303 at the upper portion of the positioning mechanism 301, and places the wafers into the grooves of the wafer carrier of the processing unit 4 in combination with compensation data given by the visual positioning mechanism 401. As there is an error in the position where the wafer carrier stops every time, the pickup unit 5 needs to cooperate with the visual positioning mechanism 401 for visually positioning, thus accurately placing the wafers into the grooves of the waver carrier.
  • S07. The processing unit 4 has multiple wafer carriers, a grinding pad is arranged below the carriers, and a lower grinding disc is arranged below the grinding pad. After one of the wafer carriers is filled with wafers, the lower grinding disc of the processing unit 4 is rotated by an angle to make another wafer carrier rotate to the loading position, and then the action of S06 is repeated to load the current carrier. Meanwhile, the unloading unit 6 presses the wafer and drains water from the wafer in the wafer carrier in S06 which has been completed before, and checks whether the wafer in the wafer Carrier is completely placed into the groove. If the placement of the wafer is unqualified, the wafer will be pressed by a flexible material again, and the size into the groove will be detected by a micrometric sensor. If it is still unqualified in the second detection, the system will give an alarm and wait for manual intervention.
  • S08. S06 and S07 are repeated to place all wafers into the grooves of the wafer carrier and check whether the placement is qualified or not. After the loading is finished, the PLC may send a loading completion signal to the processing unit 4, and then the processing unit 4 can start polishing and grinding.
  • S09. After the loading is completed, the processing unit 4 starts to operate, the unloading unit 6 takes out the wafers from the buffer water tank 701 of the unloading docking unit 7 and places the wafers into the unloading water tank 702, such that all the wafers in the unloading docking unit 7 are placed into the unloading water tank 702. A wafer material frame is placed in the unloading water tank 702, and after the material frame is full, the PLC sends full information to the MES, and the MES sends an instruction to the AGV trolley to take materials.

Specific examples are used herein for illustration of the principles and embodiments of the present disclosure. The description of the embodiments is merely used to help illustrate the method and its core principles of the present disclosure. In addition, a person of ordinary skill in the art can make various modifications in terms of specific embodiments and scope of application in accordance with the teachings of the present disclosure. In conclusion, the content of this description shall not be construed as a limitation to the present disclosure.