Wafer loading cup, polishing unit, polishing method and processing device

Abstract

The invention provides a wafer loading cup, a polishing unit, a polishing method and processing equipment, and the wafer loading cup comprises a base and a cleaning part. The base comprises a wafer bearing part and an avoiding part, a wafer bearing surface used for supporting the edge of a wafer is formed on the upper surface of the wafer bearing part, and the avoiding part penetrates through the wafer bearing part and interrupts the wafer bearing surface; the cleaning part and the base are movably arranged, the cleaning part comprises a cleaning head, a connecting base, a supporting rod and a driving device, the cleaning head and the supporting rod are fixed to the upper surface and the lower surface of the connecting base in a staggered mode respectively, and cleaning liquid paths are arranged in the supporting rod and the connecting base and used for supplying cleaning liquid to the cleaning head; and the driving device pushes the supporting rod to support the connecting seat to be close to or far away from the base, so that the upper surface of the cleaning head passes through the avoiding part to be higher than or lower than the wafer bearing surface. The loading cup can clean the polishing head on line in situ, so that the wafer processing efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical mechanical polishing, and specifically relates to a wafer loading cup, a polishing unit, a polishing method, and a processing device. Background Art

[0002] During the CMP (Chemical Mechanical Polishing) process, if the polishing liquid remains on the polishing head, crystallization will form at the outer circle and edge of the air film of the polishing head. If not cleaned in time, it is not conducive to the maintenance of the polishing head and also affects the post-cleaning effect of CMP. Summary of the Invention

[0003] In view of this, the present invention provides a wafer loading cup, a polishing unit, a polishing method, and a processing device, thereby solving or at least alleviating one or more of the above problems and other problems existing in the prior art.

[0004] To achieve the foregoing object, a first aspect of the present invention provides a wafer loading cup, comprising: a base and a cleaning part;

[0005] The base includes a wafer bearing part and an avoidance part. The upper surface of the wafer bearing part forms a wafer bearing surface for supporting the edge of the wafer. The avoidance part penetrates through the wafer bearing part and interrupts the wafer bearing surface;

[0006] The cleaning part is movably arranged with the base. The cleaning part includes a cleaning head, a connecting seat, a support rod, and a driving device. The cleaning head and the support rod are respectively and staggeredly fixed on the upper and lower surfaces of the connecting seat. The support rod and the connecting seat internally have a cleaning liquid path for supplying cleaning liquid to the cleaning head;

[0007] The driving device pushes the support rod to support the connecting seat to approach or move away from the base, so that the upper surface of the cleaning head passes through the avoidance part to be higher or lower than the wafer bearing surface.

[0008] The wafer loading cup as described above, optionally, the connecting seat is arranged along the radial direction of the loading cup. The cleaning head is installed at the outer end along the radial direction of the loading cup on the upper surface of the connecting seat, and the support rod is installed at the inner end along the radial direction of the loading cup on the lower surface of the connecting seat;

[0009] At least part of the connecting seat is arranged in the avoidance part. There is a fitting gap between the avoidance part and the connecting seat. The avoidance part has a shape consistent with the outer end.

[0010] The wafer loading cup as described above, optionally, the cleaning head includes one or more of a scraper, a brush, or a water baffle; the material of the scraper includes PTFE, the material of the brush includes PVA, and the material of the water baffle includes silicone rubber.

[0011] The wafer loading cup as described above. Optionally, the brush has a cylindrical structure with a diameter of 15 mm - 25 mm, and the top surface is 10 - 20 mm higher than the upper surface of the connecting seat.

[0012] The top surface has a plurality of parallel grooves with a depth of 0.3 mm - 0.7 mm, and the distance between two adjacent grooves is 1.5 mm - 2.5 mm.

[0013] The line connecting the center of the top surface and the center of the base is neither parallel nor perpendicular to the grooves.

[0014] The wafer loading cup as described above. Optionally, the upper surface of the connecting seat is recessed downward to form a brush mounting position, and the cleaning liquid path protrudes upward from the brush mounting position above the upper surface of the connecting seat to form a liquid outlet, and the liquid outlet is located inside the brush.

[0015] The wafer loading cup as described above. Optionally, the base includes a fixed seat and a bracket, the bracket is mounted on the fixed seat, the wafer bearing portion and the avoidance portion are formed on the bracket, and the wafer bearing surface is located on the side away from the fixed seat.

[0016] The wafer loading cup as described above. Optionally, the connecting seat and the bracket are on the same side of the fixed seat. The bottom of the fixed seat is provided with a through hole, the support rod passes through the through hole and connects the liquid supply device and the driving device. The liquid supply device is connected and supplies the cleaning liquid to the cleaning liquid path, and the driving device drives the support rod to slide relative to the through hole.

[0017] The wafer loading cup as described above. Optionally, the driving device includes a pressure sensor and a lifting rod, the lifting rod is connected to the support rod and the two are arranged in parallel, and the pressure sensor is arranged on the lifting rod.

[0018] The wafer loading cup as described above. Optionally, a bellows is arranged between the fixed seat and the connecting seat and on the outer peripheral side of the support rod. The two ends of the bellows are respectively sealed and connected to the fixed seat and the connecting seat, and the bellows is in a stretched or contracted state as the connecting seat moves away from or approaches the base.

[0019] The wafer loading cup as described above. Optionally, the bottom of the fixed seat is provided with a recessed portion, the through hole is arranged at the bottom of the recessed portion, the bellows is fixed by an annular flange and pressed on the bottom surface of the recessed portion, and the recessed portion communicates with a liquid discharge port penetrating the side wall of the fixed seat.

[0020] When the connecting seat is in the position closest to the base, a part of it is received in the recess, and the upper surface of the connecting seat is higher than the lower surface of the bracket.

[0021] When the connecting seat is in the position farthest from the base, the lower surface of the connecting seat is lower than the wafer carrying surface.

[0022] To achieve the foregoing object, a second aspect of the present invention provides a wafer polishing unit, including a polishing platen, a polishing head, a lifting device, and the wafer loading cup of the first aspect. Among them,

[0023] The polishing head can move between the polishing platen and the wafer loading cup, adsorb and move the wafer, and is used to cooperate with the wafer loading cup to exchange wafers and polish the wafer on the polishing platen.

[0024] The wafer loading cup is used to load the exchanged wafers or clean the polishing head.

[0025] The lifting device is used to lift the loading cup.

[0026] To achieve the foregoing object, a third aspect of the present invention provides a wafer polishing method, using the wafer polishing unit of the second aspect, including:

[0027] Polishing the wafer. The steps of polishing the wafer include:

[0028] Interaction step I: Control the polishing head to move to align with the wafer loading cup, control the loading cup to rise to dock with the polishing head at the first docking position, control the polishing head to adsorb the wafer, and control the loading cup to descend.

[0029] Polishing step: Control the polishing head to move to the polishing platen to polish the wafer.

[0030] Interaction step II: Control the polishing head to move to align with the wafer loading cup, control the loading cup to rise to dock with the polishing head at the first docking position, control the polishing head to release the wafer, and control the loading cup to descend.

[0031] Cleaning the polishing head. The steps of cleaning the polishing head include:

[0032] Cleaning step I: Control the polishing head to move to align with the wafer loading cup, control the loading cup to rise to dock with the polishing head at the second docking position. The distance between the loading cup and the polishing head at the second docking position is greater than the distance between the two at the first docking position.

[0033] Cleaning step II: Control the driving device to raise the upper surface of the cleaning head to fit the polishing head, control the liquid supply device to supply cleaning liquid to the cleaning head, and control the polishing head to rotate;

[0034] Cleaning step III: Control the polishing head to stop rotating, control the liquid supply device to stop supplying liquid, and control the driving device to lower the upper surface of the cleaning head to be lower than the wafer carrying surface.

[0035] For the wafer polishing method as described above, optionally, the cleaning step II further includes: According to the pressure value detected by the pressure sensor, control the pressure of the air film of the polishing head, and / or control the driving device so that the pressure value detected by the pressure sensor reaches a predetermined threshold, and the predetermined threshold is adapted to at least one of the type, material, and shape of the cleaning head.

[0036] For the wafer polishing method as described above, optionally, it further includes:

[0037] Replace different cleaning heads according to the process, and the different cleaning heads include at least one difference in the type, material, and shape of the cleaning head;

[0038] Replace different polishing heads, brackets, and connecting seats according to the process, and the different polishing heads, brackets, and connecting seats correspond to wafers of different sizes.

[0039] To achieve the foregoing purpose, a fourth aspect of the present invention provides a wafer processing device, which includes a controller, a memory, and the wafer polishing unit described in the second aspect. The controller is electrically connected to the memory, the pressure sensor, the driving device, the lifting device, and the liquid supply device. The controller is used to control the polishing unit to execute the polishing method described in the third aspect, and the memory stores the predetermined threshold.

[0040] Compared with the prior art, the wafer loading cup of the present invention integrates a cleaning head in a limited space, sets a cleaning liquid path to directly supply cleaning liquid to the cleaning head, and can make cleaning heads of various different shapes or different materials fully contact the surface to be cleaned at an appropriate pressure. While having good cleaning efficiency and cleaning effect, it does not interfere with the normal wafer loading / unloading process, perfectly adapts to the existing CMP production rhythm, and improves production efficiency without increasing additional control complexity. At the same time, the cleaning head connecting seat and bracket of the present invention can be replaced separately or synchronously, so as to be applicable to wafers of different specifications without replacing the whole wafer loading cup, effectively increasing the operation convenience of the CMP process and reducing the replacement cost. Description of the Drawings

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0042] Figure 1 It is a schematic cross-sectional view of an embodiment of the wafer loading cup of the present invention.

[0043] Figure 2 is Figure 1 a schematic cross-sectional view when cleaning the polishing head in the embodiment of

[0044] Figure 3 is Figure 1 a schematic view of an embodiment of the cleaning component in the embodiment of

[0045] Figure 4 It is a schematic view of an embodiment of the wafer polishing unit of the present invention.

[0046] Figure 5 It is a flowchart of an embodiment of the wafer polishing method of the present invention.

[0047] Figure 6 It is a schematic view of an embodiment of the wafer processing equipment of the present invention.

[0048] Reference numerals:

[0049] Wafer loading cup 100;

[0050] Base 1; Bracket 11; Fixed seat 12; Wafer bearing part 110; Wafer bearing surface 111; Avoidance part 112; Depression part 121; Through hole 122; Drain port 123; Nozzle 13; Second liquid supply pipeline 131;

[0051] Cleaning part 2; Cleaning head 21; Connecting seat 22; Support rod 23; Driving device 24; Bellows 25; Annular flange 26; Liquid outlet 221; Upper surface 222; Lower surface 223; Outer end 224; Inner end 225; Liquid inlet 231; First liquid supply pipeline 232; Lifting rod 241; Pressure sensor 242; Horizontal connecting piece 243; Actuating part 244;

[0052] Polishing head 200; Retaining ring 210; Air film 220; Polishing disc 300. Detailed implementation manners

[0053] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art shall fall within the scope of protection of the embodiments of the present invention.

[0054] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0055] In addition, in the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0056] The wafer polishing unit uses a loading cup as a device for interacting with the polishing head for the wafer, which has been used in the prior art.

[0057] The loading cup is arranged adjacent to the polishing platen to facilitate the transfer of the wafer. A wafer carrying surface is provided on one side of the upper surface of the loading cup, and the wafer can be horizontally placed on the wafer carrying surface. The loading cup can be lifted and lowered relative to the machine table to load the unpolished wafer when descending to the low position and dock with the polishing head when rising to the high position, waiting for the polishing head to adsorb the unpolished wafer or release the polished wafer.

[0058] The polishing head can move between the loading cup and the polishing platen. A retaining ring and an air film are provided on its lower surface, and the retaining ring surrounds the air film. The polishing head can adsorb the wafer to be polished through the air film and confine the wafer inside the retaining ring. The polishing liquid supply device disperses the polishing liquid on the surface of the polishing pad covering the polishing platen. The dressing device includes a dressing arm and a dressing head. The dressing arm drives the rotating dressing head to swing to dress the surface of the polishing pad to a state suitable for polishing. During the polishing operation, the polishing head presses the surface to be polished of the wafer against the surface of the rotating polishing pad and rotates and moves. The polishing liquid is distributed between the polishing pad and the wafer, and the removal of the surface material of the wafer is completed under the action of chemical mechanics.

[0059] In the wafer polishing process flow, the operating process for each wafer mainly includes:

[0060] 1) The wafer suction process, in which the polishing head moves above the loading cup, the polishing head and the loading cup are respectively controlled to descend and ascend, then the polishing head adsorbs the wafer placed on the loading cup into the retaining ring on the lower surface of the polishing head, and then the polishing head and the loading cup are respectively controlled to ascend and descend, and the polishing head is moved above the polishing pad;

[0061] 2) The polishing process, in which the surface of the wafer to be polished is pressed against the surface of the polishing pad by the polishing head, the rotation of the polishing pad is controlled, the supply device of the polishing liquid is controlled to spray the polishing liquid, the rotation and movement of the polishing head 200 are controlled, and the dressing device is controlled to dress the polishing pad;

[0062] 3) The wafer unloading process, in which after polishing is completed, the polishing head transports and unloads the wafer onto the loading cup.

[0063] In the chemical mechanical polishing process, polishing liquid remains on the polishing head, which will form crystals at the outer ring and edge positions of the air film of the polishing head. If not cleaned in time, it is not conducive to the maintenance of the polishing head and also affects the CMP effect. Especially when polishing third-generation semiconductors, due to the change of the wafer material and the polishing process, long-term use will lead to impurity accumulation, and the "white edge" phenomenon will occur when interacting with the residual polishing liquid. The "white edge" not only has strong adhesion and is more difficult to remove, but may also fall on the polishing pad and cause scratches on the wafer. Therefore, the existing equipment cannot meet the demand for continuous use, and the polishing head must be maintained regularly by shutting down the machine, which seriously affects the wafer production efficiency.

[0064] On the other hand, the internal space of the machine used for polishing third-generation semiconductors is compact. If additional on-line cleaning equipment is added, it is necessary to redesign the entire machine, which is costly and has a long result verification cycle. In view of this, the embodiment of the present invention provides a wafer loading cup 100, which enables the wafer loading cup 100 to have the function of cleaning the polishing head without substantially increasing the space occupied by the loading cup, effectively improves the problem of impurity accumulation, and at the same time does not affect the existing CMP production rhythm, realizing on-line and in-situ cleaning of the polishing head.

[0065] Figure 1 It is a schematic cross-sectional view of an embodiment of the wafer loading cup 100 of the present invention. It can be understood that in order to clearly show the internal structure therein, Figure 1 partially perspective structures are also shown. As shown in the figure, the wafer loading cup 100 includes a base 1 and a cleaning part 2. The bottom of the base 1 is connected to a lifting device, so that the wafer loading cup 100 can move up and down in the vertical direction.

[0066] On one side of the base 1 away from the bottom, a wafer carrying part 110 is provided. On the upper surface of the wafer carrying part 110, a wafer carrying surface 111 for supporting the wafer is formed. The wafer carrying surface 111 has a contour shape consistent with the edge of the wafer and contacts and supports the wafer edge with a certain width, such as an annular wafer carrying surface. An avoidance part 112 is formed on the wafer carrying part 110. The avoidance part 112 is a space penetrating through the wafer carrying part 110, and the wafer carrying surface 111 is interrupted at the avoidance part 112. Preferably, the avoidance part 112 is formed by continuously removing a part of the wafer carrying part 110 perpendicular to the wafer carrying surface 111.

[0067] The cleaning part 2 includes a cleaning head 21, a connecting seat 22, a support rod 23 and a driving device 24. The cleaning head 21 and the support rod 23 are connected and fixed through the connecting seat 22. The cleaning head 21 is fixed on the upper surface of the connecting seat 22, and one end of the support rod 23 is fixed on the lower surface of the connecting seat 22. The cleaning head 21 and the support rod 23 are misaligned with each other, that is, they do not coincide in the vertical direction. The other end of the support rod 23 penetrates through the upper surface of the base 1 and is connected to the driving device 24 in the base 1. At least part of the cleaning head 21 and the connecting seat 22 are located in the space of the avoidance part 112. A certain fitting gap is provided between the connecting seat 22 and the avoidance part 112. The support rod 23 can move relative to the base in the vertical direction under the action of the driving device 24, so as to push the connecting seat 22 closer to or farther away from the base 1. Specifically, the support rod 23 pushes at least part of the connecting seat 22 to rise in the space of the avoidance part 112. During this process, the upper surface of the cleaning head 21 also passes through the wafer carrying surface from the avoidance part 112, rising from a position lower than the wafer carrying surface 111 to a position higher than the wafer carrying surface 111, or descending from a position higher than the wafer carrying surface 111 to a position lower than the wafer carrying surface 111. Here, the high and low are measured by the upper surface of the cleaning head 21, that is, the surface for cleaning the polishing head, so that the cleaning head 21 can be lower than the wafer carrying surface 111 during the wafer sucking process and the wafer unloading process, and will not contact the wafer to cause interference or contamination, thus not affecting the existing CMP production rhythm.

[0068] The support rod 23 and the connecting seat 22 are internally provided with a cleaning liquid path for supplying cleaning liquid to the cleaning head. The cleaning liquid can be a chemical solution or deionized water or gas or a combination of the foregoing. In this way, the removal efficiency is improved through the dual action of the cleaning liquid and the cleaning head. Although there is also a liquid path in the existing loading cup, it is only used to provide deionized water to play the role of flushing and moisturizing. In the present invention, a liquid path dedicated to the cleaning head is provided in the support rod 23 and the connecting seat 22. Without changing other parts of the loading cup, special chemical solutions can be used for specific impurities, the usage amount of the cleaning liquid can be effectively reduced, and at the same time, the pollution caused by the splashing of the liquid medicine can be avoided.

[0069] In one embodiment, the connection seat 22 has an upper surface 222 and a lower surface 223 that are arranged horizontally and oppositely, and the upper surface 222 has a length direction and a width direction, and the length direction is greater than the width direction. The connection seat 22 is set so that the length direction is consistent with the radial direction of the loading cup, the cleaning head 21 is installed at the outer end 224 of the upper surface 222 along the radial direction of the loading cup, and the support rod 23 is installed at the inner end 225 of the lower surface 223 along the radial direction of the loading cup. Because the cleaning head must be close to the edge of the base to clean the gap between the retaining ring and the air film, but the edge of the base has various complex structures, such as nozzles, pipes, drains, etc. on the one hand, and there is no structure to support and fix the support rod 23 below the edge of the base on the other hand. By staggering the setting and making the support rod 23 close to the center of the base, not only can the complex structure of the edge of the base 1 be avoided, but also the existing structure close to the center of the base can be used to support and fix the support rod 23, which reduces the overall transformation cost and also helps the structure and movement of the cleaning part 2 to be more stable and provide sufficient cleaning force. In addition, it has been verified through experiments that, since the retaining ring and the air film have different heights and hardnesses during cleaning, the interaction forces between them and the cleaning head are also different. The distribution of different interaction forces is consistent with the direction of dislocation, so that the cleaning part just provides adaptability to different forces. That is, when the pressure at the retaining ring is relatively high, the larger force arm causes the cleaning part to deform slightly to adapt to it, so that the cleaning head can maintain full contact with the air film and the retaining ring; and when the pressure at the air film is relatively high, the force arm is relatively small, and the cleaning part is not easy to deform, so that the contact posture and pressure with the air film can be maintained. Preferably, the avoidance portion 112 has a shape consistent with the outer end 224, preferably an arc shape, so that a consistent matching gap is formed between the avoidance portion 112 and the outer end 224, so that the avoidance portion has a limiting effect on the circumferential direction of the connecting seat to prevent damage caused by large deformation due to force.

[0070] In one embodiment, the cleaning head 21 can be set to different types, materials or shapes to suit different cleaning needs. Preferably, the cleaning head 21 can be one or more of a scraper, a brush or a water retaining strip, wherein the scraper can be a PTFE material, the brush can be a PVA material, and the water retaining strip can be a silicone rubber, so as to have different hardness or friction strength, but all have a certain elasticity without causing damage to the air film of the polishing head. At the same time, the material of the scraper also has the property of being resistant to corrosion by chemical liquids, and the specific material can also be adjusted according to the actual chemical liquid used. The shape of the cleaning head 21 is preferably a shape that fits the edge to be cleaned of the polishing head, so that it can form full contact with the air film, the annular retaining ring and the gap between the substantially circular horizontal cross section, to ensure the cleaning effect. In one embodiment, the cleaning head 21 is set to a scraper, and the scraper is provided with a semicircular or triangular protrusion at the gap between the alignment retaining ring and the air film, and the height of the protrusion is preferably 0.3mm-0.7mm.

[0071] In one embodiment, as Figure 3 shown, the cleaning head 21 is a brush with a cylindrical structure having a wavy cleaning surface. The brush is mounted on the outer end 224 of the upper surface of the connecting seat 22 through the bottom surface of the cylinder. The top surface of the brush has a groove structure, and a plurality of grooves are parallel to each other and cover the entire top surface of the brush. The groove structure is beneficial to enhancing the cleaning effect of the brush. Preferably, the height of the brush above the upper surface of the connecting seat is 10 - 20 mm, and the diameter is 15 mm - 25 mm. The depth and spacing of the grooves are set to be slightly larger than the average particle size of the crystalline debris, which is beneficial to improving the cleaning effect and reducing the variance of the size distribution of the debris, and also makes the debris easy to be discharged along the grooves. Preferably, the depth of the grooves is 0.3 mm - 0.7 mm, and the spacing between the bottom centerlines of adjacent grooves is 1.5 mm - 2.5 mm.

[0072] Furthermore, the orientation of the grooves is further defined to form a certain angle with the direction of friction, that is to say, the top surface and side surface of the "ridge" between the grooves scrape across the gas film at a certain angle, and this angle is preferably 5° - 30°. In this embodiment, the polishing head, the wafer, and the base all have a circular horizontal cross-section. Ideally, when the polishing head is docked with the loading cup to pick up or unload the wafer, the centers of the three are on a straight line in the vertical direction. When cleaning the polishing head, the polishing head and the base are aligned, that is, the position in the horizontal direction is the same as when docking, so the centers of the two are also on a straight line in the vertical direction. To facilitate increasing friction and quickly discharging debris particles, in the same horizontal plane, the connection line between the center of the base 1 and the center of the brush is set to be neither parallel nor perpendicular to the orientation of the grooves, and preferably the two form an angle of 5° - 30°.

[0073] In one embodiment, the outer end of the upper surface of the connecting seat 22 has a brush mounting position, which is formed by a recess hollowed out from the upper surface of the connecting seat downward. One end of the internal liquid pipeline of the connecting seat 22 communicates with the internal liquid pipeline of the support rod 23, and the other end protrudes upward from the brush mounting position through the upper surface of the connecting seat to form a liquid outlet 221. After the brush is installed, the liquid outlet 221 is located inside the brush, so that the cleaning liquid can be supplied to the inside of the brush, which is not only beneficial to the cleaning liquid to fully infiltrate the entire brush, but also effectively avoids the splashing of the cleaning liquid.

[0074] In one embodiment, as Figure 1-2 shown, the base 1 includes a bracket 11 and a fixing seat 12, and the bracket 11 abuts against and is mounted on the fixing seat 12. It can be understood that, in order to clearly show the internal structure therein, Figure 2The middle bracket 11 is not in contact with and fixed to the fixed seat 12. The middle part of the bottom of the fixed seat 12 is lower than the edge part and has a cup-shaped structure. The bracket 11 is joined to the edge part of the fixed seat 12, so that the whole formed by the bracket 11 and the fixed seat 12 also has a cup-shaped structure. The wafer carrying part 110 and the avoidance part 112 are formed on the bracket 11. The wafer carrying surface 111 is located on the side away from the fixed seat 12. The avoidance part 112 penetrates through the whole bracket 11 in the vertical direction and communicates with the middle part of the fixed seat 12. During the process of sucking and unloading the wafer, the connecting seat 22 is controlled to be in contact with the bottom of the fixed seat 12, and the upper surface of the cleaning head 21 is lower than the wafer carrying surface 111, so that it will not contact the wafer and cause contamination or interference.

[0075] As shown in the figure, a through hole 122 penetrating the bottom is provided in the middle part of the bottom of the fixed seat 12. The support rod 23 passes through the through hole 122 and forms a clearance fit with the inner wall of the through hole. Among the two ends of the support rod 23 on the upper and lower sides of the fixed seat 12, one end on the upper side is connected to the connecting seat 22, and the other end on the lower side is connected to a liquid supply device (not shown) and a driving device 24. The liquid supply device communicates with the cleaning liquid path to supply cleaning liquid to the cleaning liquid path. A liquid inlet 231 for connecting the liquid supply device is provided at the bottom of the support rod 23. The liquid inlet 231 has the functions of sealing the liquid path and controlling the liquid volume, so as to control the flow rate of the cleaning liquid supplied to the cleaning head 21. The liquid inlet is connected to the first liquid supply device through the first liquid supply pipeline 232. The first liquid supply pipeline 232 is an independent pipeline for supplying liquid to the cleaning head 21, so that chemical liquid medicine can be supplied to improve the cleaning effect without affecting the structure and function of the original liquid supply pipeline. The driving device 24 drives the support rod 23 to slide relative to the through hole 122, so that the inner wall of the through hole also serves as a limiting and guiding device for the lifting movement of the support rod 23.

[0076] In one embodiment, the driving device 24 includes a pressure sensor 242 for detecting the pressure between the cleaning head 21 and the polishing head 200, so as to form a closed-loop control for the driving device 24. For example, the contact pressure between the cleaning head and the surface to be cleaned is calculated according to the feedback pressure value, and then the driving device is adjusted according to the contact pressure and the predetermined threshold. The specific adjustment amount is not only related to the cleaning requirements, but also related to the type, material and shape of the cleaning head. Further, it is also related to the state of the air film 220 of the polishing head 200. Corresponding pressure values can be preset for different cleaning requirements, types, materials and shapes of the cleaning head, so as to dynamically adjust to be close to the preset value according to the pressure value feedback by the pressure sensor. Preferably, during cleaning, the pressure of the air film 220 is controlled so that the air film protrudes from the retaining ring of the polishing head, that is, a convex surface is formed, so as to simplify the control process while achieving a good cleaning effect.

[0077] As Figure 2As shown, the driving device 24 further includes a lifting rod 241. The lifting rod 241 is arranged in parallel with the support rod 23, and the two are fixedly connected by a horizontal connecting member 243, so that the lifting rod 241 and the support rod 23 are lifted and lowered synchronously. The pressure sensor 242 is arranged on the lifting rod 241, so that the pressure between the cleaning head 21 and the polishing head 200 can be accurately measured without considering the influence of the water circuit in the support rod 23. Further, the pressure sensor 242 is arranged on the horizontal connecting member 243 and connected to the upper end of the lifting rod 241, so that the detection value of the sensor is more accurate and is beneficial to the wiring of the sensor through the horizontal connecting member 243. In addition, the lifting rod 241 is arranged at a position closer to the center of the base 1 compared with the support rod 23. At the same time, the actuating part 244 of the driving device is also arranged at the lower end of the lifting rod 241, that is, the lifting of the support rod 23 is driven by the lifting of the lifting rod 241. The existing structure near the center of the base can be used to support and fix the lifting rod 241, which will not cause great changes in the overall layout and volume of the loading cup, and also improves the running stability of the loading cup. The structure of the actuating part 244, the way of providing the actuating force and the moving way are not limited, and those skilled in the art can select a suitable solution according to actual needs. In one embodiment, the actuating part is preferably a cylinder. When the cylinder pushes the lifting rod 241 to lift and lower, the cleaning head 21 can lift and lower within a certain stroke, and the stroke can be limited by the cylinder stroke, the limiting mechanism and other connecting components, preferably 13-18 mm, so as to make full use of the existing space in the loading cup and ensure that the wafer will not be interfered or polluted.

[0078] In one embodiment, as Figure 2 shown, a bellows 25 is arranged on the outer peripheral side of the support rod 23 between the fixed seat 12 and the connecting seat 22. One end of the bellows 25 is hermetically connected to the connecting seat 22, and the other end is hermetically connected to the fixed seat 12 (for clear display, it is shown as not hermetically connected in the figure). That is to say, the bellows forms an effective seal for the matching part of the connecting seat 22 and the support rod 23 and the through hole 122, preventing the waste liquid of cleaning from entering and forming corrosion or crystallization to interfere with the movement of the support assembly. At the same time, the bellows can be in an extended or contracted state as the connecting seat 22 moves away from or close to the fixed seat 12, without affecting the lifting of the support rod 23. Preferably, the bellows 25 can be fixed by a sealing screw or a flange. A limiting structure is arranged at the end of the bellows 25, and the sealing screw or the flange presses the limiting structure and fixes it at the bottom of the fixed seat 12 to prevent the bellows from falling off the fixing part. At the same time, the limiting structure can also form a good seal.

[0079] In one embodiment, as Figure 1-2As shown, a recessed portion 121 is further provided at the bottom of the fixed seat 12. The recessed portion is lower than the middle part of the cup-shaped structure of the fixed seat 12. That is to say, the bottom of the recessed portion 121 constitutes the lowest point of the bottom of the fixed seat 12. A through hole 122 is provided on the bottom surface of the recessed portion 121. The annular flange 26 is embedded in the recessed portion 121 and fixes and presses the bellows 25 against the bottom surface of the recessed portion 121. The recessed portion 121 is communicated with a liquid discharge port 123 penetrating through the side wall of the fixed seat 12, so that cleaning liquid and the like can be quickly discharged, reducing corrosion or crystallization at the bellows or the annular flange due to waste liquid residue, and increasing additional cleaning or replacement costs.

[0080] As shown in the figure, the recessed portion 121 is arranged to accommodate at least a part of the connecting seat 22, so that the height of the entire loading cup 100 remains basically unchanged after adding the cleaning portion 2. Therefore, there is no need to change the devices and processes cooperating with the loading cup, or even the layout structure of the chemical mechanical polishing machine tool, greatly reducing the transformation and verification costs. Preferably, the connecting seat 22 is arranged such that when in the position closest to the base, the lower half of the connecting seat 22 is in the recessed portion 121 (not shown), but its upper surface is still higher than the lower surface of the bracket, so that even if there is a horizontal position deviation, there will be no interference with the bracket during rising; and when the connecting seat 22 is in the position farthest from the base, the lower surface is still lower than the wafer bearing surface 111, so that there will be no interference with the bracket during descending, ensuring the stable operation of the loading cup 100.

[0081] In one embodiment, in order to enhance the cleaning effect, a nozzle 13 is provided at the outer edge between the alignment retaining ring 210 and the air film 220 on the base 1. The nozzle 13 can be a newly provided nozzle, or an existing nozzle with a suitable angle can be reused, and the existing second liquid supply pipeline 131 of the wafer loading cup is reused. The second liquid supply pipeline is used to supply deionized water. Thus, flushing can be provided for the cleaning part when the cleaning head 21 cleans the polishing head or after cleaning is completed, achieving a better cleaning effect and promoting the discharge of the cleaning liquid from the liquid discharge port 123.

[0082] In one embodiment, the length of the connecting seat 22 is adjustable or can be replaced with different length specifications. When it is necessary to switch different cleaning operations, only the connecting seat 22 needs to be replaced to quickly adapt, with high speed and low cost. Furthermore, when replacing and docking polishing heads of different specifications, the bracket 11 can be integrally replaced with the connecting seat 22 to adapt to the specifications of the polishing head, so as to dock and clean polishing heads of different specifications. That is to say, the wafer loading cup 100 of the present invention can be easily applied to wafer polishing equipment of different specifications.

[0083] The present invention also provides a wafer polishing unit 1000, such as Figure 4As shown, it includes a polishing pad 300, a polishing head 200, a lifting device, and a wafer loading cup 100 provided in any of the foregoing embodiments. The polishing head 200 has a retaining ring 210 and an air film 220. The polishing head adsorbs and holds the wafer in the retaining ring 210 through the air film 220, so as to interact with the wafer with the wafer loading cup 100, move the wafer between the wafer loading cup 100 and the polishing pad 300, and polish the wafer on the polishing pad 300. The polishing unit 1000 may further include a polishing liquid supply device and a dressing device.

[0084] The lifting device is used to lift and lower the wafer loading cup 100, so that the loading cup 100 can move between a high position, a middle position, and a low position. The specific structure of the lifting device, the way of providing driving force, and the way of moving are not limited. Those skilled in the art can select a suitable solution according to actual needs to complete driving the wafer loading cup 100 to move vertically and stop at a specific position. Among them, the high position is used to dock with the polishing head to interact with the wafer; the middle position is used to clean the polishing head; the low position is used to interact with the loading cup 100 by other transfer devices for the wafer. Therefore, when the wafer loading cup 100 is in the high position or the low position, the connecting seat 22 is at the lowest position close to the base; only when cleaning the polishing head in the middle position, the connecting seat 22 will be in a position away from the base, so that the upper surface of the cleaning head fits the polishing head, and at this time the polishing head is aligned with the loading cup but not docked, which is beneficial to the adjustment of the cleaning head pressure and the rotation of the polishing head. In addition, when the stroke of the cleaning head 21 is not enough to adjust the required pressure, the position of the loading cup can be adjusted first, and / or the pressure of the air film of the polishing head can be adjusted, so as to realize a large range of adjustment of the cleaning pressure and adapt to different cleaning scenarios without increasing the height of the loading cup.

[0085] The present invention also provides a wafer polishing method using the above-mentioned wafer polishing unit 1000, Figure 5 which is a flowchart of an embodiment of the wafer polishing method of the present invention. As Figure 5 shown, the method includes two main steps: polishing the wafer and cleaning the polishing head. It is easy for those skilled in the art to think that there is no absolute front-back order for the two main steps, but they can be combined according to needs. For example, a step of continuously polishing multiple wafers is followed by a step of cleaning the polishing head.

[0086] The wafer polishing method of the present invention in the step of polishing the wafer includes transferring the wafer between the wafer loading cup 100 and the polishing head 200, that is, the wafer sucking process and the wafer unloading process in the wafer polishing process flow. When interacting with the wafer, the driving device 24 should be controlled so that the upper surface of the cleaning head 21 is lower than the wafer bearing surface 111. The steps of polishing the wafer include:

[0087] Interaction Step I: After the wafer is placed in the loading cup 100, control the polishing head 200 to move to align with the wafer loading cup 100, control the loading cup 100 to rise to dock with the polishing head at the first docking position, control the air film of the polishing head 200 to adsorb the wafer, and control the loading cup 100 to descend.

[0088] Polishing Step: Control the polishing head 200 to move to the polishing pad 300 to polish the wafer;

[0089] Interaction Step II: After polishing is completed, control the polishing head 200 to move to align with the wafer loading cup 100, control the loading cup 100 to rise to dock with the polishing head at the first docking position, control the air film of the polishing head 200 to release the wafer, and control the loading cup 100 to descend.

[0090] To improve the docking accuracy, the whole or part of the polishing head 200 usually can also have a vertical stroke, which is not limited in the present invention.

[0091] In the wafer polishing method of the present invention, the cleaning part 2 is used to clean the polishing head 200 in the step of cleaning the polishing head. The steps of cleaning the polishing head include:

[0092] Cleaning Step I: Control the polishing head 200 to move to align with the wafer loading cup 100, and then control the loading cup 100 to rise to dock with the polishing head at the second docking position. The distance between the loading cup 100 and the polishing head 200 at the second docking position is greater than the distance between them at the first docking position. The positions of the polishing head 200 and the wafer loading cup 100 at the second docking position are as Figure 2 shown. It can be understood that the first docking position corresponds to the position where the loading cup 100 and the polishing head 200 interact with the wafer, while the second docking position corresponds to the position where the cleaning head 21 cleans the polishing head. The closer distance between them at the first docking position is beneficial for the accurate interaction of the wafer, but not conducive to the rotation of the polishing head.

[0093] Cleaning Step II: Control the driving device 24, so that the support rod 23 pushes the connecting seat 22 to rise, making the cleaning head 21 move from below the wafer bearing surface 111 to above the wafer bearing surface 111 until the upper surface 222 fits the polishing head 200. Then control the liquid supply device to supply cleaning liquid to the cleaning head 21, and at the same time control the polishing head 200 to rotate. The cleaning head 21 cleans the polishing head by relying on the frictional force generated by abutting against the air film 220. Since there is a certain distance between the polishing head 200 and the loading cup 100 at the second docking position, the retaining ring 210 and the air film 220 will not generate unnecessary friction with the wafer bearing surface 111 during the rotation process.

[0094] Cleaning Step III: Control the polishing head 200 to stop rotating, control the liquid supply device to stop supplying liquid, and control the driving device to lower the upper surface of the cleaning head to below the wafer bearing surface 111.

[0095] In one embodiment, the cleaning step II further includes: obtaining the pressure value detected by the sensor 242, controlling the pressure of the air film 220 according to the difference between the detected value and a predetermined threshold, and / or controlling the driving device 24 such that the detected value is equal to the predetermined threshold. The predetermined threshold is adapted to at least one of the type, material, and shape of the cleaning head to meet the cleaning requirements. For example, by controlling the pressure of the air film 220 to increase or decrease the degree to which the air film protrudes from the retaining ring 210, the pressure of the contact between the cleaning head and the polishing head can be synchronously increased or decreased, so as to adapt to different cleaning pressures required when the cleaning head type is a scraper and when the cleaning head type is a brush. In addition, forming a closed-loop control through pressure detection can reduce the requirement for the accuracy during docking. In particular, as the consumable retaining ring wears during the CMP process, the detected value of the pressure sensor 242 will continuously decrease at the same second docking position. Using the polishing method of the present invention, the driving device 24 can be controlled to ensure the stability of the cleaning effect.

[0096] In addition, after adjusting the stroke of the cleaning head 21 and the pressure of the air film of the polishing head, if there is still a large difference between the detected value and the predetermined threshold, that is, the stroke of only the cleaning head and the air film is not sufficient to meet the pressure required for cleaning. At this time, the stroke of the cleaning head and the air film can be first adjusted to the minimum, and then the position of the loading cup can be adjusted to reduce the distance between the loading cup and the polishing head, and then the cleaning step II is executed. Thus, a large range of adjustment of the cleaning pressure can be achieved, and different cleaning scenarios can be adapted without increasing the height of the loading cup, without affecting other usage links of the loading cup.

[0097] In one embodiment, the wafer polishing method of the present invention further includes replacing different cleaning heads according to the process. Different cleaning heads include at least one difference in the type, material, and shape of the cleaning head. For example, when mainly cleaning the adsorption air film, a rectangular scraper made of PTFE material is preferably used; when mainly cleaning the gap, a cylindrical brush made of PVA material is preferably used. In some usage scenarios, the connecting seat and the cleaning head can also be replaced integrally.

[0098] In some scenarios, the same polishing unit may be used to polish wafers of different sizes. For example, 6-inch and 8-inch wafers may share the same polishing unit. The wafer polishing method of the present invention further includes replacing different polishing heads, brackets, and connecting seats according to the process, so that the three can synchronously adapt to wafers of different sizes, without affecting the control logic in the entire method process, and also enabling the cleaning head to achieve consistent functions in the processing of wafers of different sizes.

[0099] The present invention also provides a wafer processing apparatus, and a wafer can be transported in the wafer processing apparatus to a wafer processing unit 1000 for chemical mechanical polishing of the wafer.

[0100] In one embodiment, as Figure 6 shown, the wafer processing apparatus further includes a controller and a memory. The controller is electrically connected to components inside the apparatus such as the memory, a pressure sensor, a driving device, a lifting device, and a liquid supply device. Predetermined thresholds related to cleaning are stored in the memory, so that the controller can control the polishing unit 1000 to perform the polishing method of any of the foregoing embodiments.

[0101] The above embodiments are only used to illustrate the embodiments of the present invention, rather than limiting the embodiments of the present invention. Those of ordinary skill in the relevant art can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present invention. The patent protection scope of the embodiments of the present invention shall be defined by the claims.

Claims

1. A wafer loading cup, characterized in that, Comprising: A base and a cleaning part; The base includes a wafer carrying part and an avoidance part. On the upper surface of the wafer carrying part, a wafer carrying surface for supporting the edge of the wafer is formed. The avoidance part penetrates through the wafer carrying part and interrupts the wafer carrying surface; The cleaning part is movably arranged with the base. The cleaning part includes a cleaning head, a connecting seat, a support rod and a driving device. The cleaning head and the support rod are respectively and staggeredly fixed on the upper and lower surfaces of the connecting seat. The support rod and the connecting seat internally have a cleaning liquid path for supplying cleaning liquid to the cleaning head; The driving device pushes the support rod to support the connecting seat to approach or move away from the base, so that the upper surface of the cleaning head passes through the avoidance part to be higher or lower than the wafer carrying surface.

2. The wafer loading cup according to claim 1, wherein The connecting seat is arranged along the radial direction of the loading cup. The cleaning head is installed at the outer end along the radial direction of the loading cup on the upper surface of the connecting seat, and the support rod is installed at the inner end along the radial direction of the loading cup on the lower surface of the connecting seat; At least part of the connecting seat is arranged in the avoidance part. There is a fitting gap between the avoidance part and the connecting seat. The avoidance part has a shape consistent with the outer end; 3. The wafer loading cup according to claim 2, wherein, The cleaning head includes one or more of a scraper, a brush or a water baffle; the material of the scraper includes PTFE, the material of the brush includes PVA, and the material of the water baffle includes silicone rubber.

4. The wafer loading cup according to claim 3, wherein The brush is of a cylindrical structure with a diameter of 15 mm - 25 mm, and the top surface is 10 - 20 mm higher than the upper surface of the connecting seat; The top surface has a plurality of parallel grooves, the depth of the grooves is 0.3 mm - 0.7 mm, and the distance between two adjacent grooves is 1.5 mm - 2.5 mm; The connection line between the center of the top surface and the center of the base is neither parallel nor perpendicular to the grooves.

5. The wafer loading cup according to claim 4, characterized in that, The upper surface of the connecting seat is recessed downward to form a brush mounting position. The cleaning liquid path protrudes upward from the brush mounting position to form a liquid outlet on the upper surface of the connecting seat, and the liquid outlet is located inside the brush.

6. The wafer loading cup according to any one of claims 1-5, characterized in that, The base includes a fixed seat and a bracket. The bracket is installed on the fixed seat. The wafer carrying part and the avoidance part are formed on the bracket, and the wafer carrying surface is located on the side away from the fixed seat; 7. The wafer loading cup according to claim 6, wherein, The connecting seat and the bracket are on the same side of the fixed seat. A through hole is provided at the bottom of the fixed seat. The support rod passes through the through hole and connects a liquid supply device and the driving device. The liquid supply device communicates with and supplies the cleaning liquid to the cleaning liquid path, and the driving device drives the support rod to slide relative to the through hole; 8. The wafer loading cup according to claim 7, wherein, The driving device includes a pressure sensor and a lifting rod. The lifting rod is connected to the support rod and the two are arranged in parallel. The pressure sensor is arranged on the lifting rod; 9. The wafer loading cup according to claim 7, wherein A bellows is arranged between the fixed seat and the connecting seat and on the outer peripheral side of the support rod. The two ends of the bellows are respectively and hermetically connected to the fixed seat and the connecting seat. The bellows is in a stretched or contracted state as the connecting seat moves away from or approaches the base.

10. The wafer loading cup according to claim 9, wherein, The bottom of the fixed seat is provided with a recess, the through hole is arranged at the bottom of the recess, the corrugated pipe is fixedly pressed at the bottom surface of the recess through an annular flange, and the recess communicates with a liquid discharge port penetrating through the side wall of the fixed seat; When the connecting seat is in the position closest to the base, a part of it is accommodated in the recess, and the upper surface of the connecting seat is higher than the lower surface of the bracket; When the connecting seat is in the position farthest from the base, the lower surface of the connecting seat is lower than the wafer carrying surface.

11. A wafer polishing unit, characterized in that, Comprising a polishing disc, a polishing head, a lifting device and a wafer loading cup as described in any one of claims 1-10, wherein, The polishing head can move between the polishing disc and the wafer loading cup, adsorb and move the wafer, and is used to cooperate with the wafer loading cup to exchange the wafer and polish the wafer on the polishing disc; The wafer loading cup is used to load the exchanged wafer or clean the polishing head; The lifting device is used to lift the loading cup.

12. A wafer polishing method, characterized in that, Using the wafer polishing unit as described in claim 11, comprising: Polishing the wafer, the steps of polishing the wafer include: Interaction step I, controlling the polishing head to move to align with the wafer loading cup, controlling the loading cup to rise to dock with the polishing head at the first docking position, controlling the polishing head to adsorb the wafer, and controlling the loading cup to descend; Polishing step, controlling the polishing head to move to the polishing disc to polish the wafer; Interaction step II, controlling the polishing head to move to align with the wafer loading cup, controlling the loading cup to rise to dock with the polishing head at the first docking position, controlling the polishing head to release the wafer, and controlling the loading cup to descend; Cleaning the polishing head, the steps of cleaning the polishing head include: Cleaning step I, controlling the polishing head to move to align with the wafer loading cup, controlling the loading cup to rise to dock with the polishing head at the second docking position, and the distance between the loading cup and the polishing head at the second docking position is greater than the distance between the two at the first docking position; Cleaning step II, controlling the driving device to raise the upper surface of the cleaning head to fit the polishing head, controlling the liquid supply device to supply cleaning liquid to the cleaning head, and controlling the polishing head to rotate; Cleaning step III, controlling the polishing head to stop rotating, controlling the liquid supply device to stop supplying liquid, and controlling the driving device to lower the upper surface of the cleaning head to be lower than the wafer carrying surface.

13. The wafer polishing method according to claim 12, wherein The cleaning step II further includes: according to the pressure value detected by the pressure sensor, controlling the pressure of the air film of the polishing head, and / or controlling the driving device, so that the pressure value detected by the pressure sensor reaches a predetermined threshold, and the predetermined threshold is adapted to at least one of the type, material, and shape of the cleaning head.

14. A wafer processing device, characterized in that, The wafer processing equipment includes a controller, a memory and the wafer polishing unit as described in claim 11, the controller is electrically connected to the memory, the pressure sensor, the driving device, the lifting device and the liquid supply device, the controller is used to control the polishing unit to execute the polishing method as described in any one of claims 12-13, and the memory is used to store the predetermined threshold.

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