CN116967929A

CN116967929A - Wafer polishing system

Info

Publication number: CN116967929A
Application number: CN202310861472.5A
Authority: CN
Inventors: 郑东州; 徐枭宇
Original assignee: Hangzhou Zhonggui Electronic Technology Co ltd
Current assignee: Hangzhou Zhonggui Electronic Technology Co ltd
Priority date: 2023-07-13
Filing date: 2023-07-13
Publication date: 2023-10-31

Abstract

The invention discloses a wafer polishing system, comprising: a front end module; the wafer polishing unit comprises a polishing transmission mechanism; a wafer cleaning unit; a wafer transfer path extending at least at the wafer cleaning unit; the front end module, the wafer cleaning unit and the wafer polishing unit are sequentially and adjacently arranged; the wafer transmission channel is internally provided with a first transfer station, a second transfer station and a third transfer station, a first transmission device and a second transmission device; the first transmission device is used for realizing wafer transmission between the first transfer station and the second transfer station; the second transmission device is used for realizing the transmission of the wafer between the second and third transfer stations; the third transfer station is also used for transferring the wafer between the wafer cleaning unit and the wafer polishing unit. The invention divides the wafer transmission travel in the wafer transmission channel into two sections which are respectively completed by the first transmission device and the second transmission device, thereby reducing the volume, being capable of carrying out complex actions in a narrow space and having faster transmission speed; further processing possibilities can be realized by arranging different forms of transmission.

Description

Wafer polishing system

Technical Field

The invention belongs to the technical field of manufacturing of semiconductor integrated circuit chips, and particularly relates to a wafer polishing system.

Background

Chemical mechanical polishing planarization (Chemical Mechanical Planarization, simply CMP) apparatus generally includes a semiconductor device front end module (EFEM), a cleaning unit, and a polishing unit. The EFEM mainly comprises a wafer box for storing wafers, a wafer conveying manipulator, an air purifying system and the like; the cleaning unit mainly comprises megasonic cleaning parts, rolling brush cleaning parts, drying parts, devices for conveying wafers between the parts and the like, wherein the number of the megasonic cleaning parts is different; the polishing unit generally includes a table, a polishing disk, a polishing head, a polishing arm, a dresser, a polishing liquid arm, and the like, each of which is arranged on the table in accordance with a processing position. The wafer starts from EFEM, is transferred to the polishing unit through a series of transfer systems to carry out a planarization technology combining mechanical and chemical, and the polished wafer is moved to a cleaning area through a series of transfer systems to clean surface impurities and dry, and finally returns to the wafer storage box of EFEM.

Because the wafer needs to carry out different processes at different stations inside the CMP equipment, the transmission of the wafer inside the equipment is extremely important, and the output of the equipment and the yield of the wafer are seriously affected, so that the transmission system is required to be fast, stable and accurate.

The transmission layout of the conventional CMP equipment has the following difficulties: 1) The available space is limited, and the wafer transmission system is generally required to have the capability of realizing complex actions, and most of the existing equipment adopts a special mechanical arm for purchase, so that the cost is high, the maintainability is poor, the expandability is poor, and the wafer transmission system is limited by the functions of the mechanical arm; 2) The transmission efficiency is low, and generally, one transmission component needs to continuously complete multi-step wafer transmission actions, so that the time is consumed for completing one action cycle, the transmission circulation efficiency of the wafers between stations is low, and the improvement of the output of equipment is not facilitated; 3) The compatibility is poor, and the expansion of equipment and the expansion of technology are not facilitated.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a wafer polishing system which can finish complex wafer transmission actions in a narrow space, and has the advantages of high transmission speed and high transmission efficiency.

The technical scheme adopted for solving the technical problems is as follows: a wafer polishing system comprising:

a front end module;

the wafer polishing unit comprises a polishing transmission mechanism;

a wafer cleaning unit;

a wafer transfer path extending at least at the wafer cleaning unit;

the front end module, the wafer cleaning unit and the wafer polishing unit are sequentially and adjacently arranged;

the wafer transmission channel is internally provided with a first transfer station, a second transfer station, a third transfer station, a first transmission device and a second transmission device;

the first transmission device is used for realizing wafer transmission between the first transfer station and the second transfer station;

the second transmission device is used for realizing the transmission of the wafer between the second transfer station and the third transfer station;

the third transfer station is also used for transferring the wafer between the wafer cleaning unit and the wafer polishing unit.

Further, the third transfer station at least comprises two working heights, and the third transfer station is provided with a third transfer table;

at the first working height, the wafer realizes the transmission between the second transfer station and the third transfer station;

at the second working height, the third intermediate turntable receives the wafer transferred from the polishing transfer mechanism.

Further, the transfer of the pair of wafers by the transfer device comprises the translation of the wafers, or comprises the overturning of the wafers, or comprises the translation and overturning of the wafers;

and the transmission of the second pair of wafers by the transmission device comprises the translation of the wafers, or comprises the overturning of the wafers, or comprises the translation and the overturning of the wafers.

Further, the first transmission device and the second transmission device are positioned on the same side of the first transfer station; or the first transmission device and the second transmission device are positioned on the opposite sides of the first transfer station; or the first transmission device and the second transmission device are positioned between the first transfer station and the second transfer station; or the first conveying device and the second conveying device are positioned between the second transfer station and the third transfer station.

Further, the first transmission device and/or the second transmission device comprise a sliding table extending along the wafer transmission channel and a wafer seat capable of translating along the sliding table, and the wafer seat is used for bearing the wafer so as to realize the translation transmission of the wafer.

Further, the first transmission device and/or the second transmission device comprise a rotating body capable of rotating around a central shaft of the first transmission device and/or the second transmission device, an extension arm connected to the rotating body, and a middle rotating table base connected with the extension arm, wherein the extension arm swings along with the rotating body to drive wafers on the middle rotating table base to be transmitted along an arc-shaped track.

Further, the extension arm comprises a plurality of folding arm bodies which are movably connected.

Further, the first transmission device or the second transmission device comprises a turnover shaft and a clamping arm connected to the turnover shaft, wherein the clamping arm is used for clamping a wafer and can drive the wafer to turn along with the movement of the turnover shaft.

Further, the first or second conveying device comprises a horizontal transverse shaft, a vertical longitudinal shaft capable of moving along the horizontal transverse shaft, a base capable of moving along the vertical longitudinal shaft, and a clamping jaw for clamping the wafer.

Further, the first transmission device or the second transmission device further comprises a turnover body movably connected to the base, the clamping jaw is arranged on the turnover body, and the turnover body drives the clamping jaw to turn over so as to realize turnover of the wafer.

Further, the first or second transmission device comprises a base, a lifting mechanism movably connected to the base, at least one connecting rod connected with the lifting mechanism, a finger driving box and a finger for clamping or adsorbing the wafer.

Further, the wafer cleaning unit comprises a first cleaning area and a second cleaning area which are positioned at two sides of the wafer transmission channel, and the first cleaning area and the second cleaning area comprise a plurality of cleaning boxes.

Furthermore, a buffer box is arranged in the wafer cleaning unit or the wafer polishing unit, and the third transfer station is arranged corresponding to the buffer box.

Further, the front end module comprises a front end transmission mechanism for realizing wafer transmission between the front end module and the first transfer station.

The invention has the beneficial effects that 1) the wafer transmission stroke in the wafer transmission channel is divided into two sections which are respectively completed by the first transmission device and the second transmission device, so that the volumes of the first transmission device and the second transmission device are reduced, the first transmission device and the second transmission device can perform complex actions in a narrow space, and the transmission speed is higher; 2) The process is flexible, and more process possibilities such as single-sided polishing and double-sided polishing can be realized by setting different transmission modes (wafer overturning, wafer translation and the like); 3) The transmission efficiency is improved, more wafers are in the transmission process at the same time, the idle time of the transfer station is reduced, and the capability of the machine station transmission system for transmitting the wafers is improved; 4) The layout is more reasonable, the space utilization rate is high, the switching of the wafer in the second transfer station and the third transfer station is realized through the second transmission device, and the logic of the wafer polishing unit for entering and exiting the wafer is more reasonable; 5) The structure is simple, the transmission is more stable, only simple translation or overturning and other actions are needed between transfer stations, the requirement on the hardware structure is low, and the stability of equipment is improved; 6) The third transfer station sets transfer transmission of the polished wafer and the unpolished wafer at different working heights, so that mutual pollution between the polished wafer and the unpolished wafer can be avoided; 7) The expansibility and compatibility of the equipment are stronger, and different equipment or process requirements can be realized only by changing a certain transmission step; 8) The transmission efficiency is high, the first transmission device and the second transmission device respectively realize specific actions, each action is in a specific space, and mutual avoidance between motions is reduced.

Drawings

Fig. 1 is a top plan view of a wafer polishing system according to the present invention.

Fig. 2 is a schematic diagram of a cooperation structure of a first transfer device, a third transfer table and a polishing transfer mechanism according to the first embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a first transmission device or a second transmission device according to a second embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a first transmission device or a second transmission device in a third embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a first transmission device or a second transmission device in a fourth embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a first transmission device or a second transmission device in a fifth embodiment of the present invention.

Fig. 7 is a schematic structural diagram of a first transmission device or a second transmission device in a sixth embodiment of the present invention.

Fig. 8 is a schematic structural diagram of a buffer box in the present invention.

The device comprises a 1-front end module, a 11-front end transmission mechanism, a 2-wafer polishing unit, a 21-polishing transmission mechanism, a 3-wafer cleaning unit, a 31-cleaning area I, a 32-cleaning area II, a 33-cleaning box, a 34-cache box, a 341-water spraying device, a 35-cleaning mechanical arm, a 36-drying box, a 4-wafer transmission channel, a 51-first transfer station, a 52-second transfer station, a 53-third transfer station, a 531-third transfer table, a 61-transmission device I, a 62-transmission device II, a 631-sliding table, a 632-wafer seat, a 641-rotating body, 642-extending arms, 643-transfer table seats, 651-rotating shafts, 652-clamping arms, 661-horizontal transverse shafts, 662-vertical longitudinal shafts, 663-bases, 664-665-rotating bodies, 671-bases, 672-lifting mechanisms, 673-connecting rods, 675-finger driving boxes, 675-fingers and 7-wafers.

Detailed Description

In order to make the present invention better understood by those skilled in the art, the following description will make clear and complete descriptions of the technical solutions of the embodiments of the present invention with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

As shown in fig. 1, a wafer polishing system includes a front end module 1, a wafer polishing unit 2, a wafer cleaning unit 3, and a wafer transfer channel 4, where the wafer transfer channel 4 extends at least in the wafer cleaning unit 3, the wafer polishing unit 2 includes a polishing transfer mechanism 21, the front end module 1 includes a front end transfer mechanism 11, a cleaning robot 35 is disposed in the wafer cleaning unit 3, and a buffer box 34 is disposed in the wafer cleaning unit 3 or the wafer polishing unit 2.

In this embodiment, the front end module 1, the wafer cleaning unit 3 and the wafer polishing unit 2 are sequentially and adjacently arranged, the wafer cleaning unit 3 includes a first cleaning area 31 and a second cleaning area 32 located at two sides of the wafer conveying channel 4, and the first cleaning area 31 and the second cleaning area 32 each include a plurality of cleaning boxes 33. The first cleaning area 31 and the second cleaning area 32 can be symmetrically arranged or can be differently arranged, and different combinations and sequences can be configured according to the actual conditions of the equipment. A drying box 36 may be provided at each of the first cleaning zone 31 and the second cleaning zone 32 near the end of the front end module 1.

The wafer transfer channel 4 is provided with a first transfer station 51, a second transfer station 52, a third transfer station 53, a first transfer device 61 and a second transfer device 62.

The first conveying device 61 is used for conveying the wafer between the first transfer station 51 and the second transfer station 52; the second transfer device 62 is used for transferring the wafer between the second transfer station 52 and the third transfer station 53. The third transfer station 53 is also used for transfer of wafers between the wafer cleaning unit 3 and the wafer polishing unit 2.

The transfer of the wafer 7 by the first transfer device 61 includes translation of the wafer; or turning over the wafer, namely finishing the turning over of the wafer; or both translation and flipping of the wafer.

Likewise, the transfer of the wafer 7 by the second transfer device 62 includes translation of the wafer; or turning over the wafer, namely finishing the turning over of the wafer; or both translation and flipping of the wafer.

Regarding the relative positional relationship among the first transfer device 61, the second transfer device 62, the first transfer station 51, the second transfer station 52, and the third transfer station 53, and the positional relationship with the wafer transfer path 4, specifically, the first transfer device 61 and the second transfer device 62 may be located on the same side of the first transfer station 51; alternatively, the first conveyor 61 and the second conveyor 62 may be located on opposite sides of the first transfer station 51; in both cases, the first and second transfer devices 61 and 62 are located on opposite sides of the wafer transfer channel 4.

Alternatively, the first and second transfer devices 61, 62 may be located between the first and second transfer stations 51, 52; alternatively, the first and second conveyors 61, 62 may be located between the second and third transfer stations 52, 53; in both cases, the first and second transfer devices 61 and 62 are located at opposite intermediate positions of the wafer transfer passage 4.

In this embodiment, the first transfer station 51, the second transfer station 52 and the third transfer station 53 may be virtual working positions, that is, the transfer stations are concepts in a three-dimensional space, and their projections in the vertical direction are fixed, but may extend upward or downward in the vertical direction, not limited to a specific point, in other words, the transfer stations are three-dimensional in the Z-axis direction and relatively fixed in the X-axis and Y-axis directions; of course, the transfer station may also be a table structure with a solid body.

The third transfer station 53 is disposed corresponding to the position of the buffer boxes 34, that is, when the buffer boxes 34 are symmetrically disposed in the first cleaning region 31 and the second cleaning region 32, the third transfer station 53 is disposed between the two buffer boxes 34.

The third transfer station 53 comprises at least two working levels, and the third transfer station 53 is provided with a third transfer table 531, i.e. the third transfer station 53 has a physical table structure.

At the first working height, the wafer achieves transfer between the second transfer station 52 and the third transfer station 53; at the second working level, the third transfer table 531 receives the wafer 7 transferred from the polishing transfer mechanism 21.

In the present invention, the front end module 1 is responsible for storing wafers and placing the wafers on the first transfer station 51, providing unpolished wafers to the apparatus, and the front end transfer mechanism 11 is used to transfer wafers between the front end module 1 and the first transfer station 51. I.e. the front end transport mechanism 11 is responsible for transferring wafers to be polished to the first transfer station 51 and for transferring cleaned polished wafers in the drying oven 36.

The buffer box 34 receives the polished wafer from the third transfer station 53 and is ready for the wafer to enter the wafer cleaning unit 3 for cleaning; the cleaning robot 35 is responsible for transferring the wafer 7 between the plurality of cleaning tanks 33 in the wafer cleaning unit 3; the polishing transfer mechanism 21 is responsible for the wafer entering and exiting the wafer polishing unit 2, which is movable in the wafer transfer path 4, i.e. in this case the wafer transfer path 4 extends not only in the wafer cleaning unit 3 but also in the wafer polishing unit 2.

The third transfer station 53 is responsible for receiving polished wafers from the wafer polishing unit 2, and the second transfer station 52 is responsible for receiving unpolished wafers from the first transfer station 51 and moving the unpolished wafers to above the third transfer station 53 waiting for the polishing transport mechanism 21 to take the wafers into the polishing area of the wafer polishing unit 2.

Example 1

As shown in fig. 2, the first conveying device 61 includes a sliding table 631 extending along the wafer conveying channel 4, and a wafer seat 632 capable of translating along the sliding table 631, where the wafer seat 632 is used to support the wafer 7, specifically, may support the wafer 7 horizontally, so as to implement the translation conveying of the wafer 7. I.e. the wafer 7 can be transferred in translation from the first transfer station 51 to the second transfer station 52.

In this embodiment, the transfer of the wafer 7 by the first transfer device 61 includes translation of the wafer, and does not include flipping of the wafer.

The structure of the second transmission device 62 may be the same as that of the first transmission device 61 or may be different from that of the first transmission device.

When the transmission structures are the same, the wafer transmission process of the invention is that the front end transmission mechanism 11 transmits unpolished wafers to the first transfer station 51, the first transmission device 61 transmits the wafers 7 on the first transfer station 51 to the second transfer station 52, that is, the wafer seat translates to the second transfer station along the sliding table, and the second transmission device 62 transmits the wafers 7 on the second transfer station 52 to the third transfer station 53, that is, the other wafer seat 632 translates to the third transfer station 53 along the sliding table 631, at which time the third transfer station 53 is at the first working height;

the polishing transfer mechanism 21 can move to the upper side of the third transfer station 53, and can take the unpolished wafer on the wafer seat 632 by lifting, and the implementation of the above functions is the prior art and will not be repeated;

the polishing transfer mechanism 21 transfers the unpolished wafer into the polishing area of the wafer polishing unit 2 for polishing; the wafer seat 632 is shifted and reset to the second transfer station 52 along the sliding table 631, and waits for the next unpolished wafer to be transferred from the front end module 1; at this time, avoidance is also made for the polishing transfer mechanism 21 to place the polished wafer on the third turntable 531;

after the polishing of the wafer 7 is completed, the polished wafer is clamped by the polishing transmission mechanism 21, is moved to the upper side of the third transfer station 53, and can be placed on the third transfer station 531 by lifting, and at this time, the third transfer station 531 is at the second working height;

the wafer on the third transfer table 531 is transferred into the buffer tank 34, the state of the wafer 7 in the buffer tank 34 is as shown in fig. 8, and in order to keep the wafer wet and rinse out part of the polishing residual liquid, a plurality of water spraying devices 341 are provided in the buffer tank 34;

the cleaning robot 35 sequentially transfers the wafers 7 in the plurality of cleaning tanks 33 in a certain order, and finally moves to a drying tank 36, and the wafers are transferred to a designated place by the front end transfer mechanism 11 after being dried.

Example two

As shown in fig. 3, the first conveying device 61 includes a rotating body 641 rotatable about its own center axis, a projecting arm 642 connected to the rotating body 641, and a intermediate rotating table 643 connected to the projecting arm 642. The rotator 641 is fixedly installed in the wafer transfer passage 4, and may be a motor or a rotating cylinder; the arm 642 swings with the rotator 641, so as to drive the wafer 7 on the transfer table 643 to transfer along an arc track, thereby realizing the transfer of the wafer 7 from the first transfer station 51 to the second transfer station 52.

To increase flexibility and operating mode adaptability, the extension arm 642 may include a plurality of movably coupled folding arms, with rotational coupling between adjacent folding arms.

Example III

As shown in fig. 4, the first conveying device 61 includes a turning shaft 651, and a clamping arm 652 connected to the turning shaft 651, where the turning shaft 651 extends along the width direction of the wafer conveying channel 4, and the end of the turning shaft 651 may be rotatably connected to any position, and of course, the turning shaft 651 may also be a motor or a rotating cylinder, and the clamping arm 652 is used for clamping the wafer 7 and may move along with the turning shaft 651, so as to drive the wafer 7 to turn over, i.e. to realize turning over of the wafer 7, i.e. the turning angle of the turning shaft 651 is 180 °.

In this embodiment, the transfer of the wafer 7 by the first transfer device 61 includes flipping of the wafer, and does not include translation of the wafer.

Example IV

As shown in fig. 5, the first conveying device 61 includes a horizontal transverse shaft 661 extending along the wafer conveying channel 4, a vertical longitudinal shaft 662 movable along the horizontal transverse shaft 661, a base 663 movable along the vertical longitudinal shaft 662, a turnover body 665 movably connected to the base 663, and a clamping jaw 664 for clamping the wafer 7, where the clamping jaw 664 is disposed on the turnover body 665, so that the turnover body 665 drives the clamping jaw 664 to turn over to realize the turnover of the wafer 7. Here, the holding jaw 664 holds the wafer 7 in a state where the wafer 7 is horizontal, and the turning axis of the turning body 665 is perpendicular to the extending direction of the horizontal transverse shaft 661.

In this embodiment, the transfer of the wafer 7 by the first transfer device 61 includes translation and flipping of the wafer.

The first transmission device 61 of this embodiment is compatible with two movement modes, namely turn-over and non-turn-over. When the wafer is finished with the first surface polishing, the transfer process may be performed again, and in the second transfer process, the first transfer device 61 transfers the wafer according to another embodiment, and when the wafer is at the second transfer station 52, the state of the wafer is opposite to that in the first transfer process, and if the subsequent transfer is the same as the movement in the first transfer process, the wafer may finish the second surface polishing.

Of course, the above embodiment is an embodiment when the first transmission device 61 is compatible with two movement modes, and the wafer double-sided polishing effect can be achieved when any one of the front end transmission mechanism 11, the first transmission device 61, and the second transmission device 62 has two movement modes.

Example five

As shown in fig. 6, the difference between the present embodiment and the fourth embodiment is that the base 663 is directly movably connected to the vertical longitudinal axis 662, and the clamping jaw 664 cannot be turned over at this time, but can only be lifted up and down along the vertical longitudinal axis 662 by the base 663, and can be translated left and right along the horizontal transverse axis 661 by the vertical longitudinal axis 662.

Example six

As shown in fig. 7, the first conveyor 61 includes a base 671, a lifting mechanism 672 movably connected to the base 671, at least one link 673 connected to the lifting mechanism 672, a finger-driving cassette 674, and a finger 675 for holding or adsorbing the wafer 7.

To increase flexibility and operating mode adaptability, the number of links 673 is two or more, and adjacent links 673 are rotatably connected.

The finger 675 is connected with the finger driving box 674, and devices such as an air cylinder and a negative pressure component are arranged in the finger driving box 674, so that the finger 675 can carry a wafer in a clamping, adsorbing and other modes, and devices such as a rotary air cylinder, a size rack and a motor can be arranged in the finger driving box 674 to enable the finger 675 to have a rotary function; the finger drive box 674 is connected with a connecting rod 673; the finger driving box 674 and the connecting rod 673, the adjacent connecting rods 673 and the connecting rod 673 and the lifting mechanism 672 can be relatively rotated by arranging a belt, a gear and other mechanisms, and the telescopic mechanism is formed by mutually rotating the components. The lifting mechanism 672 and the base 671 can be lifted and lowered by a cylinder, a screw rod or a size rack and the like, and the whole body can rotate relative to the base 671.

Example seven

The wafer 7 is in a vertical state while in the purge bin 33; the wafer 7 is in a horizontal or vertical state in relation to a specific selected drying mode while in the drying oven 36; the wafer 7 is in a horizontal state at the first transfer station 51, the second transfer station 52, and the third transfer station 53.

Since the wafer has its crystal face upward and its back downward in the front end transfer mechanism 11, but the wafer is required to have its crystal face downward and its back upward in the polishing region of the wafer polishing unit 2, the wafer needs to be turned over and turned over.

Therefore, in the present embodiment, the first transmission device 61 selects the specific structure in the first embodiment, and the second transmission device 62 selects the specific structure in the fourth embodiment, so as to realize the transmission and turnover of the wafer.

Example eight

Of course, the wafer may not be turned over, that is, the first and second conveyors 61 and 62 may only translate and transfer the wafer.

In this embodiment, the first transmission device 61 is a specific structure in the first embodiment, and the second transmission device 62 is a specific structure in the fifth embodiment, so as to realize the transmission of the wafer.

Example nine

In this embodiment, the first transmission device 61 is any one of the structures of the first, second and fifth embodiments, and the second transmission device 62 is any one of the structures of the third, fourth and sixth embodiments.

The foregoing detailed description is provided to illustrate the present invention and not to limit the invention, and any modifications and changes made to the present invention within the spirit of the present invention and the scope of the appended claims fall within the scope of the present invention.

Claims

1. A wafer polishing system comprising:

a front end module (1);

a wafer polishing unit (2) including a polishing transfer mechanism (21);

a wafer cleaning unit (3);

a wafer transfer path (4) extending at least in the wafer cleaning unit (3);

the front end module (1), the wafer cleaning unit (3) and the wafer polishing unit (2) are sequentially and adjacently arranged; the method is characterized in that:

the wafer transmission channel (4) is internally provided with a first transfer station (51), a second transfer station (52), a third transfer station (53), a first transmission device (61) and a second transmission device (62);

the first transmission device (61) is used for realizing wafer transmission between the first transfer station (51) and the second transfer station (52);

the second transmission device (62) is used for realizing wafer transmission between the second transfer station (52) and the third transfer station (53);

the third transfer station (53) is also used for transferring wafers between the wafer cleaning unit (3) and the wafer polishing unit (2).

2. The wafer polishing system as recited in claim 1, wherein:

the third transfer station (53) at least comprises two working heights, and the third transfer station (53) is provided with a third transfer table (531);

at the first working height, the wafer realizes the transmission between the second transfer station (52) and the third transfer station (53);

at the second working height, the third transfer table (531) receives the wafers (7) transferred from the polishing transfer mechanism (21).

3. The wafer polishing system as recited in claim 1, wherein:

the first transmission device (61) transmits the wafer (7) and comprises the translation of the wafer, or comprises the overturning of the wafer, or comprises the translation and overturning of the wafer;

the transmission of the second transmission device (62) to the wafer (7) comprises the translation of the wafer, or comprises the overturning of the wafer, or comprises the translation and overturning of the wafer.

4. The wafer polishing system as recited in claim 1, wherein: the first transmission device (61) and the second transmission device (62) are positioned on the same side of the first transfer station (51); alternatively, the first transmission device (61) and the second transmission device (62) are positioned on opposite sides of the first transfer station (51); or the first transmission device (61) and the second transmission device (62) are positioned between the first transfer station (51) and the second transfer station (52); alternatively, the first (61) and second (62) transfer devices are located between the second (52) and third (53) transfer stations.

5. The wafer polishing system as recited in claim 1, wherein: the first conveying device (61) and/or the second conveying device (62) comprise a sliding table (631) extending along the wafer conveying channel (4), and a wafer seat (632) capable of translating along the sliding table (631), and the wafer seat (632) is used for supporting the wafer (7) so as to realize translation conveying of the wafer (7).

6. The wafer polishing system as recited in claim 1, wherein: the first transmission device (61) and/or the second transmission device (62) comprise a rotating body (641) capable of rotating around a central shaft of the first transmission device, an extension arm (642) connected to the rotating body (641) and a middle rotating table seat (643) connected with the extension arm (642), wherein the extension arm (642) swings along with the rotating body (641) to drive a wafer (7) on the middle rotating table seat (643) to transmit along an arc track.

7. The wafer polishing system as recited in claim 6, wherein: the reach arm (642) includes a plurality of movably connected folding arms.

8. The wafer polishing system as recited in claim 1, wherein: the first conveying device (61) or the second conveying device (62) comprises a turnover shaft (651) and a clamping arm (652) connected to the turnover shaft (651), wherein the clamping arm (652) is used for clamping the wafer (7) and can drive the wafer (7) to turn along with the movement of the turnover shaft (651).

9. The wafer polishing system as recited in claim 1, wherein: the first conveying device (61) or the second conveying device (62) comprises a horizontal transverse shaft (661), a vertical longitudinal shaft (662) capable of moving along the horizontal transverse shaft (661), a base (663) capable of moving along the vertical longitudinal shaft (662), and a clamping jaw (664) for clamping a wafer (7).

10. The wafer polishing system as recited in claim 9, wherein: the first conveying device (61) or the second conveying device (62) further comprises a turnover body (665) movably connected to the base (663), the clamping jaw (664) is arranged on the turnover body (665), and the turnover body (665) drives the clamping jaw (664) to turn over so as to realize turnover of the wafer (7).

11. The wafer polishing system as recited in claim 1, wherein: the first conveying device (61) or the second conveying device (62) comprises a base (671), a lifting mechanism (672) movably connected to the base (671), at least one connecting rod (673) connected with the lifting mechanism (672), a finger driving box (674) and a finger (675) for clamping or adsorbing a wafer (7).

12. The wafer polishing system as recited in claim 1, wherein: the wafer cleaning unit (3) comprises a first cleaning area (31) and a second cleaning area (32) which are positioned at two sides of the wafer conveying channel (4), and the first cleaning area (31) and the second cleaning area (32) comprise a plurality of cleaning boxes (33).

13. The wafer polishing system as recited in claim 1, wherein: the wafer cleaning unit (3) or the wafer polishing unit (2) is internally provided with a buffer box (34), and the third transfer station (53) is arranged corresponding to the buffer box (34).

14. The wafer polishing system as recited in claim 1, wherein: the front end module (1) comprises a front end transmission mechanism (11) for realizing wafer transmission between the front end module (1) and the first transfer station (51).