Chemical mechanical polishing equipment and chemical mechanical polishing method

Abstract

The invention relates to the technical field of semiconductor wafer processing, and provides chemical mechanical polishing equipment and a chemical mechanical polishing method. The chemical mechanical polishing apparatus includes: a polishing disk; an annular track is arranged on the lower surface of the top plate; the head assembly comprises a driving device and a bearing head, and the upper end of the driving device is slidably installed on the annular rail so as to drive the head assembly to slide along the annular rail; the side part of the driving device is provided with a convex limiting part; a limiting assembly is arranged on the lower surface of the top plate and comprises a first check block, a second check block and a swing limiting piece movably limited between the first check block and the second check block, the swing limiting piece and the limiting part are partially overlapped in the vertical direction, and the limiting part is limited by the first check block in the clockwise direction and limited by the second check block in the anticlockwise direction through the swing limiting piece. The sliding range of the head assembly along the annular track is 360-380 degrees, so that the head assembly can return to the initial position clockwise or anticlockwise to interact with the interaction cup in a centering manner.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor wafer processing, and particularly relates to a chemical mechanical polishing device and a chemical mechanical polishing method. Background Art

[0002] In the production process of large-scale integrated circuits, extremely high requirements are placed on the flatness of wafers. Currently, the planarization of wafers is achieved by using the chemical mechanical polishing (CMP, Chemical Mechanical Polishing) process, and the chemical mechanical polishing device is the main device for completing the chemical mechanical polishing process. The key performance indicators of the chemical mechanical polishing device include processing accuracy indicators, yield indicators, and efficiency indicators. The processing accuracy indicator is the flatness indicator. Generally, it is required that the global flatness of the polished wafer reaches the nanometer level or even the atomic level, which requires that each component of the chemical mechanical polishing device has high stiffness, reduces deformation and offset, and requires that each moving component is accurately positioned to ensure the stability, reliability, and accuracy of the overall operation; the yield indicator requires a reduction in the number of defective wafers such as wafer fragmentation, scratching, and warping; the efficiency indicator can be expressed as WPH (Wafer Per Hour, the number of wafers produced per hour), and it is required that the device operates efficiently.

[0003] Currently, in the conventional ring-orbital chemical mechanical polishing device, the head assembly for wafer polishing is usually hoisted onto the ring orbit, and the head assembly slides along the ring orbit to switch between different polishing stations. Since the head assembly is usually connected with structures such as power cables and air pipes, it is impossible to achieve 360° infinite unidirectional free rotation. Therefore, fixed limit blocks are often set on the ring orbit to rigidly limit the head assembly to prevent the cables and air pipes from being twisted and broken when the twisting angle is greater than 360°.

[0004] However, since the fixed limit block itself occupies a certain angular space, the head assembly cannot achieve full coverage of the entire circular track of 360° in both clockwise and counterclockwise directions. That is to say, the head assembly cannot slide back to its original position along one direction starting from its original position. For example, if the original position is on the left side of the fixed limit block, after the head assembly slides along the circular track to the right side of the fixed limit block, it cannot cross the fixed limit block and return to its original position. This causes the head assembly, after loading and unloading the wafer from the loading and unloading cup at the original position, sliding to the polishing pad for polishing, to be unable to continue sliding back to the same loading and unloading cup to place the wafer along the same direction, but instead has to return along the original path to the same loading and unloading cup. As a result, the head assembly only slides repeatedly within a partial range of the circular track, leading to severe local wear of the circular track, and the circular track is prone to local tilting or collapse, affecting the sliding smoothness of the head assembly and its positioning accuracy at the loading and unloading cup and the polishing pad, thereby reducing the wafer processing precision, and even causing wafer breakage and reducing the yield. In addition, the movement path of the head assembly is limited and it can only return to its original position from one side. Especially in embodiments with two or more head assemblies, it is difficult to efficiently coordinate the movement of multiple head assemblies. During the mutual avoidance process, it causes ineffective movement actions for wafer polishing and reduces the wafer processing efficiency. Summary of the Invention

[0005] The present application provides a chemical mechanical polishing device and a chemical mechanical polishing method to solve or alleviate at least some of the above-mentioned problems.

[0006] According to one aspect of the present application, a chemical mechanical polishing device for wafer processing is provided, including: A polishing pad, A top plate located above the polishing pad, with a circular track provided on its lower surface; A head assembly, including a driving device and a carrier head connected to the lower end of the driving device. The carrier head is used to carry the wafer to the polishing pad for polishing. The upper end of the driving device is slidably mounted on the circular track to drive the head assembly to slide along the circular track; a protruding limiting portion is configured on the side of the driving device; A limiting assembly is provided on the lower surface of the top plate. The limiting assembly includes a first stop block and a second stop block arranged at an arc interval concentric with the circular track, and a swing limiting member movably limited between the two. In the clockwise direction, the first stop block is located downstream of the second stop block. The swing limiting member partially overlaps with the limiting portion in the vertical direction. The limiting portion is limited by the first stop block in the clockwise direction and by the second stop block in the counterclockwise direction via the swing limiting member, so that the sliding range of the head assembly along the circular track is 360 to 380 degrees, enabling the head assembly to return to the initial position both clockwise and counterclockwise and be centered and interact with the interaction cup at the initial position.

[0007] Optionally, the first stopper and the second stopper are arranged such that when the limiting portion is limited by the first stopper or the second stopper, the projections of the carrier head and the polishing pad on the horizontal plane do not overlap, so that the contaminants on the carrier head fall outside the polishing pad during limiting, preventing the contaminants from contaminating the polishing pad and further contaminating or scratching the wafer during polishing.

[0008] Optionally, the swing limiting member includes an arc-shaped track concentric with the annular track and a movable limiting block slidably mounted on the arc-shaped track. The first stopper and the second stopper are respectively arranged at both ends of the arc-shaped track. The movable limiting block partially overlaps with the limiting portion in the vertical direction. The limiting portion is limited by the first stopper in the clockwise direction and by the second stopper in the counterclockwise direction via the movable limiting block.

[0009] Optionally, the movable limiting block includes a first side facing the first stopper and a second side facing the second stopper; when the limiting portion moves clockwise, it can abut against the second side of the movable limiting block and push the movable limiting block until the first side of the movable limiting block abuts against the first stopper, so as to be limited by the first stopper; when the limiting portion moves counterclockwise, it can abut against the first side of the movable limiting block and push the movable limiting block until the second side of the movable limiting block abuts against the second stopper, so as to be limited by the second stopper.

[0010] Optionally, the planes where the first side and the second side of the movable limiting block are located extend along the radial direction of the annular track; the sides of the first stopper and the second stopper facing each other extend along the radial direction of the annular track; the two sides of the limiting portion abutting against the movable limiting block match the shape of the movable limiting block, so as to form a surface contact between the two when the limiting portion abuts against the movable limiting block.

[0011] Optionally, the swing limiting member includes a limiting swing rod longitudinally arranged between the first stopper and the second stopper. The first end of the limiting swing rod swings around a swing axis so that its second end swings and limits between the first stopper and the second stopper. The swing axis is not on the arc where the first stopper and the second stopper are located. A limiting column protruding downward is provided at the position of the limiting swing rod corresponding to the limiting portion. The limiting column partially overlaps with the limiting portion in the vertical direction. The limiting portion is limited by the first stopper in the clockwise direction and by the second stopper in the counterclockwise direction via the limiting column.

[0012] Optionally, the first stop block and the second stop block are configured as cylindrical shapes with the same size. The first side of the limiting swing rod facing the first stop block and the second side facing the second stop block are respectively configured as arc-shaped notches recessed inward at the second end. The arc-shaped notches match the radius of the cylindrical shape. When the limiting part moves clockwise, it can abut against the limiting post to push the limiting swing rod until the arc-shaped notch on the first side of the limiting swing rod abuts against the first stop block, so as to be limited by the first stop block; when the limiting part moves counterclockwise, it can abut against the limiting post to push the limiting swing rod until the arc-shaped notch on the second side of the limiting swing rod abuts against the second stop block, so as to be limited by the second stop block.

[0013] Optionally, the distance between the first stop block and the second stop block is set such that the sliding range of the limiting part from the position limited by the first stop block to the position limited by the second stop block counterclockwise is 360 degrees to 380 degrees.

[0014] Optionally, the sliding range of the head assembly on the annular track is 365 degrees to 375 degrees.

[0015] Optionally, the limiting part is configured to be magnetically repulsive from the first stop block and the second stop block respectively to form magnetic buffer limiting.

[0016] Optionally, the driving device is configured to drive the head assembly to slide along the annular track and control the head assembly to stop at the initial position; when the head assembly is at the initial position, the limiting part is located at the original position between the first stop block and the second stop block, and the limiting part is configured to be able to move 360 degrees along the annular track to return to the original position, so that the head assembly slides 360 degrees along the annular track to return to the initial position.

[0017] Optionally, the chemical mechanical polishing equipment includes a loading and unloading cup at the initial position and below the head assembly; the loading and unloading cup is used to interact with the carrier head to provide a wafer to the carrier head or receive the wafer unloaded from the carrier head.

[0018] Optionally, the head assembly is configured to: pick up a wafer from the loading and unloading cup, slide along the annular track to carry the wafer to the polishing pad for polishing, and then continue to slide along the annular track in the same sliding direction back to the loading and unloading cup to unload the wafer.

[0019] Optionally, pressure sensors are provided on the sides of the first stopper and the second stopper facing each other, and the pressure sensors are communicatively connected to the driving device; the pressure sensors are configured to emit a hard limit signal when detecting the pressure applied by the swing limiting member, and the driving device drives the head assembly to slide to the initial position in a direction opposite to that of the previous drive and at a speed lower than that of the previous drive based on receiving the hard limit signal.

[0020] Optionally, a distance measuring sensor is provided on the side of one of the first stopper and the second stopper facing the swing limiting member, and the distance measuring sensor is communicatively connected to the driving device; the distance measuring sensor is configured to detect the detection distance between the distance measuring sensor and the limiting portion when the limiting portion is limited between the first stopper and the second stopper, and emit an offset signal when the detection distance is greater than the distance between the distance measuring sensor and the limiting portion when the limiting portion is at the original position; the driving device drives the head assembly to slide to the initial position at a speed lower than that of the previous drive based on the offset signal.

[0021] Optionally, the chemical mechanical polishing equipment includes more than two head assemblies, and a limiting assembly corresponding to each head assembly is provided on the lower surface of the top plate; the horizontal position of the overlapping part of the swing limiting member and the limiting portion of each limiting assembly matches the horizontal distance from the driving device where the limiting portion of its corresponding head assembly protrudes, and the vertical position of the overlapping part of the swing limiting member and the limiting portion of each limiting assembly matches the vertical distance from the upper end of the driving device of the limiting portion of the corresponding head assembly; The horizontal distance from the driving device where the limiting portion of one head assembly protrudes and the vertical distance from the upper end of the driving device are respectively greater than or less than those of the limiting portion of another head assembly, so that the head assemblies are not interfered by the limiting assemblies of other head assemblies when sliding along the annular track.

[0022] Optionally, the chemical mechanical polishing equipment includes more than two head assemblies, and a limiting assembly corresponding to each head assembly is provided on the lower surface of the top plate; each limiting assembly has the same size and is arranged at intervals on the same circumference; the limiting portion of each head assembly is configured to be telescopable in and out or movable up and down to retract or move down for avoidance when passing through the limiting assembly not corresponding to it, and extend or move up for limiting when passing through the limiting assembly corresponding to it.

[0023] Optionally, the chemical mechanical polishing equipment includes three head assemblies, two polishing pads, and three interaction cups; the three head assemblies are a first head assembly, a second head assembly, and a third head assembly respectively, and the three can move relative to each other; the two polishing pads are a rough polishing pad and a fine polishing pad; the three interaction cups are a first loading and unloading cup, a second loading and unloading cup, and a moisturizing cup located at the initial positions of the first head assembly, the second head assembly, and the third head assembly respectively; each head assembly moves to the rough polishing pad and the fine polishing pad in sequence to polish the wafer. Each head assembly is configured to be able to slide 360 degrees to 380 degrees along the annular track, and one or more of the three head assemblies reciprocate within a partial range of the annular track during a circle of sliding along the annular track for wafer polishing to cooperate with the sliding of other head assemblies.

[0024] According to another aspect of the present application, there is provided a chemical mechanical polishing method for the chemical mechanical polishing equipment as described in the foregoing aspect, and the method includes: Controlling the head assembly to pick up the wafer from the loading and unloading cup; Driving the head assembly to slide along the annular track to the polishing pad to polish the wafer at the polishing pad; After polishing, driving the head assembly to slide back along the annular track to the loading and unloading cup, and controlling the head assembly to unload the polished wafer to the loading and unloading cup; Wherein, the direction in which the head assembly carries the current wafer and slides along the annular track is opposite to the direction in which the head assembly carried the previous wafer and slid along the annular track.

[0025] According to the chemical mechanical polishing equipment and the chemical mechanical polishing method of the present application, the first stop block and the second stop block can provide hard limits for the sliding of the head assembly along the annular track, preventing the head assembly from sliding too far and causing excessive torsion and entanglement or breakage of the cables and air pipes connected to the head assembly. And through the swinging cooperation of the swinging limiting member of the limiting assembly with the first stop block and the second stop block, the swinging limit of the limiting portion between the first stop block and the second stop block is realized, so that the head assembly can slide along the annular track for at least 360 degrees, so that it can return to the initial position after sliding one circle, ensuring uniform force and high levelness of the annular track, so that the head assembly slides smoothly and has high position accuracy, improving the wafer polishing accuracy. In addition, the technical solution of the present application can also optimize the sliding route of the head assembly during operation, expand the sliding range of the head assembly, increase the selectivity of the route, significantly improve the operating efficiency of the chemical mechanical polishing equipment, and improve WPH. Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments described in the embodiments of the present application. For those of ordinary skill in the art, other accompanying drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic diagram of a chemical mechanical polishing device; Figure 2 It is a partial schematic diagram of a chemical mechanical polishing device according to an embodiment of the present application; Figure 3 It is Figure 2 a schematic diagram of the top plate and the head assembly in Figure 4 It shows Figure 3 a bottom view of the top plate in Figure 5 It shows Figure 4 an enlarged view of part A in Figure 6 It is a schematic diagram of a limit assembly according to another embodiment of the present application; Figure 7 It shows Figure 3 a cross-sectional view taken along line B-B in Figure 8 It shows Figure 3 a cross-sectional view taken along line B-B in , where another head assembly and its limit assembly are schematically shown in dashed lines; Figure 9 It shows Figure 2 a schematic diagram of the first step of a polishing running process of the chemical mechanical polishing device in Figure 10 It shows Figure 9 the next step of Figure 11 It shows Figure 10 the next step of Figure 12 It shows Figure 11 the next step of Figure 13 It shows Figure 12 the next step of Figure 14 It shows Figure 13 the next step of Figure 15 It shows Figure 14 the next step of Figure 16 It is a flowchart of a chemical mechanical polishing method according to an embodiment of the present application.

[0028] Reference numerals: 100, head assembly; 1001, first head assembly; 1002, second head assembly; 1003, third head assembly; 10, carrier head; 110, driving device; 111, limiting part; 1101, first slider; 1102, second slider; 1103, third slider; 1104, fourth slider; 20, polishing disc; 201, first polishing disc; 202, second polishing disc; 30, polishing pad; 40, dressing device; 41, dressing arm; 42, dressing head; 50, polishing liquid supply device; 60, loading and unloading cup; 601, first loading and unloading cup; 602, second loading and unloading cup; 603, moisturizing cup; 70, top plate; 71, annular track; 711, first loop; 712, second loop; 721, first stop block; 722, second stop block; 723, movable limiting block; 7231, movable base; 7232, movable convex part; 724, arc track; 725, limiting swing rod; 726, swing shaft; 727, limiting column; W, wafer. Detailed implementation manners

[0029] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the protection scope of the embodiments of the present application.

[0030] In the description of the present application, 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 drawings, and are only for the convenience of describing the present application 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, and therefore should not be construed as a limitation to the present application.

[0031] In addition, in the description of the present application, 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 may be a mechanical connection or an electrical connection, or it may be the communication inside two elements. It may 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.

[0032] Figure 1Schematic diagram of a chemical mechanical polishing apparatus, the chemical mechanical polishing apparatus including a head assembly 100, a polishing platen 20, a polishing pad 30, a dressing device 40, a polishing liquid supply device 50, and an interaction cup located on the side of the polishing platen 20. In Figure 1 an embodiment, the interaction cup is a loading and unloading cup 60, and the head assembly 100 includes a carrier head 10. The polishing pad 30 is disposed on the upper surface of the polishing platen 20 and rotates therewith; the horizontally movable carrier head 10 is disposed above the polishing pad 30, and a wafer W to be polished is attracted to its lower surface; the dressing device 40 includes a dressing arm 41 and a dressing head 42, and the dressing arm 41 drives the rotating dressing head 42 to swing to dress the surface of the polishing pad 30 to a state suitable for polishing; the polishing liquid supply device 50 disperses the polishing liquid on the surface of the polishing pad 30; during the polishing operation, the carrier head 10 presses the surface of the wafer W to be polished against the surface of the polishing pad 30, and the polishing liquid is distributed between the polishing pad 30 and the wafer W, and the removal of the surface material of the wafer W is completed under the action of chemical mechanics.

[0033] In chemical mechanical polishing, the operation process of each wafer W mainly includes: (1) a wafer suction process, moving the carrier head 10 above the loading and unloading cup 60 and then adsorbing the wafer W placed on the loading and unloading cup 60 to the carrier head 10; (2) a polishing process, moving the wafer W to the polishing pad through the carrier head 10 for polishing; (3) a wafer unloading process, after the polishing is completed, transporting the wafer W back by the carrier head 10 and unloading the wafer W onto the loading and unloading cup 60.

[0034] To improve the moving efficiency and stability of the carrier head 10, the carrier head 10 is arranged to slide along an annular track 71. As Figure 2 shown in the partial schematic diagram of a chemical mechanical polishing apparatus according to an embodiment of the present application, Figure 2 the annular track 71 is schematically shown by a dashed line therein. Figure 3 is Figure 2 a specific schematic diagram of the top plate 70 and the head assembly 100 in Figure 3, the head assembly 100 includes a driving device 110 and a carrier head 10 drivingly connected to the lower end of the driving device 110. The carrier head 10 is used to carry the wafer W to the polishing pad 20 for polishing. The upper end of the driving device 110 is slidably mounted on the annular track 71 to drive the head assembly 100 to slide along the annular track 71. In a specific embodiment, the driving device 110 may include a first motor for driving the head assembly 100 to slide along the annular track 71 and a second motor for driving the carrier head 10 to rotate self - to polish the wafer W at the polishing pad 20. Preferably, the first motor may be a linear motion motor driven by electromagnetic force. For example, the annular track 71 may be provided with a magnetic track, which generates an electromagnetic effect with the magnetic block of the linear motion motor to drive the head assembly 100 to slide and start / stop along the magnetic track.

[0035] Figure 2 Two juxtaposed polishing pads 20 and three head assemblies 100 are shown in [Figure]. As shown in the figure, they are the first polishing pad 201, the second polishing pad 202, the first head assembly 1001, the second head assembly 1002, and the third head assembly 1003 respectively. Each head assembly 100 has an initial position correspondingly. An interaction cup is arranged at the initial position. The interaction cup is used to accurately align with the head assembly and then conduct interactions. "Interaction" includes that the interaction cup provides wafers for the head assembly so that the head assembly loads wafers, the interaction cup receives the wafers unloaded by the head assembly, and the head assembly conducts cleaning or cache moisturizing at the interaction cup, etc. The initial position can be understood as the original position of the head assembly 100. When the head assembly 100 does not perform polishing work, it conducts cleaning at the original position or stops at the original position for standby. The interaction cup at the initial position may be a loading / unloading cup 60. The first loading / unloading cup 601 and the second loading / unloading cup 602 are respectively arranged at the initial positions of the first head assembly 1001 and the second head assembly 1002 in the figure. The interaction cup at the initial position may also be a moisturizing cup 603. Figure 2 The moisturizing cup 603 is arranged at the initial position of the third head assembly 1003 in [Figure]. The moisturizing cup 603 is used to cache and moisturize the head assembly 100 and / or the wafer W thereon. For example, during the process that a head assembly 100 carries the wafer W and runs along the annular track 71, if both polishing pads 20 are performing polishing work, this head assembly 100 needs to wait. At this time, moisturizing can be conducted at the moisturizing cup 603 to prevent the liquid on the surface of the wafer W from drying and crystallizing. In addition, the loading / unloading cup 60 can also spray moisturizing liquid towards the head assembly or the wafer for moisturizing and cleaning. In an alternative embodiment, the first polishing pad 201 is a rough polishing pad, the second polishing pad 202 is a fine polishing pad, and the head assembly 100 can carry the wafer W to conduct two - stage polishing at the rough polishing pad and the fine polishing pad in sequence to achieve an ultra - high polishing flatness approaching the atomic level.

[0036] Figure 3 is Figure 2 a schematic diagram of the top plate 70 and the head assembly 100 in [Figure]. Figure 2 The top plate 70 in [Figure] is generally square.Figure 3 Only a circular part of the top plate 70 is shown. In an actual implementation, the top plate 70 can be set to a square, circular, annular or other appropriate shape according to the space design and the overall layout requirements of the equipment. By Figure 3 It can be seen that a protruding limiting part 111 is constructed on the side of the driving device 110. A limiting component is arranged on the lower surface of the top plate 70. The limiting component includes a first stop block 721 and a second stop block 722 that are arranged at arc intervals concentric with the annular track 71, and a swing limiting member that is movably limited between the first stop block 721 and the second stop block 722. The swing limiting member and the limiting part 111 partially overlap in the vertical direction so as to be able to swing and stop the limiting part 111. In Figures 3 - 5 the shown implementation, the swing limiting member includes an arc track 724 concentric with the annular track 71 and a movable limiting block 723 slidably mounted to the arc track 724. The first stop block 721 and the second stop block 722 are respectively arranged at both ends of the arc track 724. In Figure 3 the clockwise direction indicated by the hollow arrow, the first stop block 721 is located downstream of the second stop block 722. The movable limiting block 723 and the limiting part 111 partially overlap in the vertical direction so that the movable limiting block 723 can movably stop the limiting part 111. The limiting part 111 is limited by the first stop block 721 in the clockwise direction and by the second stop block 722 in the counterclockwise direction via the movable limiting block 723, so that the sliding range of the head assembly 100 on the annular track 71 is 360 degrees to 380 degrees, preferably 370 degrees.

[0037] It should be understood that the arc where the first stop block 721 and the second stop block 722 are located can be arranged inside or outside the annular track 71. If it is arranged inside, the arc radius is smaller than that of the annular track 71. Correspondingly, the limiting part 111 is arranged on the side of the driving device 110 facing the center of the annular track 71; if the arc is arranged outside, the radius is larger than that of the annular track 71. Correspondingly, the limiting part 111 is arranged on the side of the driving device 110 facing away from the center of the annular track 71; the positions of other related structures are also adaptively arranged.

[0038] According to the technical solution of the present application, whether during the process of driving the head assembly 100 to slide along the annular track 71 by the driving device 110 during processing or during the process of manually pushing the head assembly 100 to slide for equipment debugging and maintenance during non-processing, the first stop block 721 and the second stop block 722 can both provide hard limits for the sliding of the head assembly 100 along the annular track 71, preventing the head assembly 100 from sliding too far and causing excessive torsion of the cables and air pipes connected to the head assembly 100, resulting in entanglement or breakage. And through the active cooperation of the swing limiting member with the first stop block 721 and the second stop block 722, the swing limit of the limiting portion 111 between the first stop block 721 and the second stop block 722 is realized, enabling the head assembly 100 to slide along the annular track 71 by at least 360 degrees, so that it can return to the initial position after sliding one circle. This enables the head assembly to return to the initial position from both sides of the limiting assembly, that is, it can either return to the initial position along the original path or continue to slide 360 degrees along the same direction to return to the initial position, avoiding problems such as path redundancy and low wafer processing efficiency caused by having to return to the original position along the original path when the sliding range is less than 360 degrees, and avoiding local wear or skew of the annular track 71 caused by reciprocating only on a part of the annular track 71 for a long time. Therefore, the technical solution of the present application can ensure that the annular track 71 is evenly stressed and has a high levelness, so that the head assembly slides smoothly and has a high position accuracy, ensuring the wafer processing accuracy. In addition, especially when there are two or more head assemblies 100 provided on the annular track 71, returning along the original path may be blocked by other head assemblies 100, and other head assemblies 100 must make way, resulting in cumbersome making-way actions, excessive redundant movements, and reduced equipment operation efficiency. Therefore, the technical solution of the present application can optimize the sliding route of the head assembly 100 during operation, promote the coordinated cooperation during the relative movement of multiple head assemblies, significantly improve the operation efficiency of the chemical mechanical polishing equipment, and increase the WPH.

[0039] In a preferred embodiment, the first stop block 721 and the second stop block 722 are configured such that when the limiting portion 111 is limited by the first stop block 721 or the second stop block 722 via the swing limiter, the projections of the carrier head 10 and the polishing disk 20 on the horizontal plane do not overlap, so that when the limiting portion 111 indirectly hits the first stop block 721 or the second stop block 722 for hard limiting, contaminants on the carrier head 10 fall outside the polishing disk 20 during the collision without contaminating the polishing disk and the wafer. Furthermore, in order to mitigate the impact of the limit portion 111 when it is hard-limited by the first stop block 721 or the second stop block 722 via the swing limit member, it is desired to have a buffer limit structure. However, in the corrosive environment of chemical mechanical polishing filled with polishing liquid, if the swing limit member or the first stop block 721 and the second stop block 722 are made of elastic rubber material, the rubber may be corroded or carbonized and fail after a period of time. For this reason, the swing limit member (specifically, for example, the movable limit block 723) and the first stop block 721 and the second stop block 722 can be set to be magnetic, and the swing limit member is configured to magnetically repel the first stop block 721 and the second stop block 722, respectively, to form a magnetic buffer limit without generating a strong impact, thereby increasing the stability of the head assembly 100 during movement, reducing the drop of contaminants caused by the impact, and ensuring the cleanliness of the polishing.

[0040] In a specific embodiment, the movable stopper 723 includes a first side facing the first stopper 721 and a second side facing the second stopper 722. For example, the first side is Figure 4 , Figure 5 The right side of the movable limit block 723 in the second side is Figure 4 , Figure 5 The movable stop block 723 may include a movable base 7231 that is slidably engaged with the arc track 724 and a movable protrusion 7232 that extends downward from the movable base 7231. The movable base 7231 can slide along the arc track 724 and is used to contact the first stop block 721 or the second stop block 722 for movable stop, and the movable protrusion 7232 is used to contact the stop portion 111 to stop the stop portion 111. The width of the movable base 7231 may be wider than the movable protrusion 7232, and the movable protrusion 7232 is centered with respect to the movable base 7231, or the movable base 7231 and the movable protrusion 7232 may have the same width. The right side surface of the movable base 7231 and the right side surface of the movable protrusion 7232 can be collectively regarded as the first side of the movable limit block 723 , and the left side surface of the movable base 7231 and the left side surface of the movable protrusion 7232 can be collectively regarded as the second side of the movable limit block 723 .

[0041] When the limiting part 111 moves clockwise, it can abut against the second side of the movable limiting block 723 and push the movable limiting block 723 to abut against the first stop block 721 on the first side of the movable limiting block 723, so that the limiting part 111 is stopped and limited by the first stop block 721 via the movable limiting block 723. When the limiting part 111 moves counterclockwise, it can abut against the first side of the movable limiting block 723 and push the movable limiting block 723 to abut against the second stop block 722 on the second side of the movable limiting block 723, so that the limiting part 111 is stopped and limited by the second stop block 722 via the movable limiting block 723. The distance between the first stop block 721 and the second stop block 722 is set such that the sliding range of the limiting part 111 from the position limited by the first stop block 721 to the position limited by the second stop block 722 counterclockwise is 360 degrees to 380 degrees. Thus, it can allow the head assembly 100 to slide 360 degrees along the annular track 71 and return to the original position under the control of the driving device 110, optimize the sliding route of the head assembly 100, improve the operation efficiency of the device, and at the same time, it can also ensure that the cables, air pipes, etc. connected to the head assembly 100 will not be wound or broken, ensuring the reliability and service life of related components. When the sliding range is exactly 360 degrees, if the head assembly 100 rebounds by hitting the first stop block 721 or the second stop block 722 through the movable limiting block 723, it is difficult to ensure that the head assembly 100 can slide a full circle. Therefore, preferably, the sliding range is 365 degrees to 375 degrees, more preferably 370 degrees, so that the range exceeding 360 degrees can provide a rebound space when the head assembly 100 rebounds by hitting the first stop block 721 or the second stop block 722, or provide an overshoot space when stopping beyond the initial position due to inertia, reducing the continuous vibration caused by hard devices.

[0042] Figure 6 FIG. shows a schematic diagram of a limiting component according to another embodiment of the present application. Instead of Figures 3 - 5 the structures such as the arc-shaped track 724 and the movable limiting block 723 shown in, the limiting component may further include a limiting swing rod 725 longitudinally arranged between the first stop block 721 and the second stop block 722. The first end of the limiting swing rod 725 swings around a swing axis 726 that is not on the arc where the first stop block 721 and the second stop block 722 are located, so that the second end of the limiting swing rod 725 swings and limits between the first stop block 721 and the second stop block 722. A limiting column 727 protruding downward is provided at the position of the limiting swing rod 725 corresponding to the limiting part 111. The limiting column 727 partially overlaps with the limiting part 111 in the vertical direction to stop the limiting part 111. The limiting part 111 is limited by the first stop block 721 in the clockwise direction and by the second stop block 722 in the counterclockwise direction via the limiting column 727.

[0043] Specifically, as Figure 6, the first stopper 721 and the second stopper 722 are configured as cylindrical shapes with the same dimensions. The first side of the limiting swing rod 725 facing the first stopper 721 and the second side facing the second stopper 722 are respectively configured as inwardly concave arc-shaped notches at its second end. The arc-shaped notches match the radius of the cylinder. When the limiting part 111 moves clockwise, it can abut against the limiting column 727 to push the limiting swing rod 725 to engage with the arc-shaped notch on the first side of the limiting swing rod 725 and abut against the first stopper 721, so as to be limited by the first stopper 721; when the limiting part 111 moves counterclockwise, it can abut against the limiting column 727 to push the limiting swing rod 725 to make the arc-shaped notch on the second side of the limiting swing rod 725 abut against the second stopper 722, so as to be limited by the second stopper 722.

[0044] Similarly to the foregoing, the limiting swing rod 725 can be arranged to be magnetically repulsive from the first stopper 721 and the second stopper 722 respectively to form magnetic buffer limiting.

[0045] The swing limiting member in the form of the limiting swing rod 725 can replace the arc-shaped track 724 and the movable limiting block 723 with the limiting swing rod 725, simplifying the structure and reducing the probability of movement jamming. In addition, other beneficial effects are similar to the foregoing.

[0046] During the polishing process of the wafer W, the precise alignment of the head assembly 100 with the loading and unloading cup 60 is a prerequisite for ensuring the stable picking and placing of the wafer W, accurate positioning, and no fragmentation. The driving device 110 is configured to drive the head assembly 100 to slide along the annular track 71 and control the head assembly 100 to stop at the initial position. At the initial position, the center of the carrier head 10 of the head assembly 100 is aligned with the center of the loading and unloading cup 60 below it for precise wafer W loading and unloading, avoiding fragmentation caused by the wafer W hitting the edge of the carrier head 10 or the loading and unloading cup 60 due to the misalignment of their centers. When the head assembly 100 is at the initial position, the limiting portion 111 is at the original position between the first stop block 721 and the second stop block 722. The original position can be the midpoint between the first stop block 721 and the second stop block 722, so that there is the same amount of overshoot space on both sides of the original position. The limiting portion 111 is configured to be able to move 360 degrees along the annular track 71 to return to the original position, so that the head assembly 100 slides 360 degrees along the annular track 71 to return to the initial position. When performing the polishing operation, the head assembly 100 picks up the wafer W from the loading and unloading cup 60, slides along the annular track 71 to carry the wafer W to the polishing platen 20 for polishing, and then continues to slide along the annular track 71 in the same sliding direction to return to the loading and unloading cup 60 to unload the wafer W. Thus, the head assembly 100 can move 360 degrees in one direction to complete one wafer W polishing, without having to move to the polishing platen 20 in one direction and then repeat the same path in the opposite direction during one wafer W polishing process. In the case of only one head assembly 100, this technical solution of the present application can avoid severe local wear or skew of the annular track 71 caused by the head assembly 100 only traveling back and forth along a section of the annular track 71 for a long time; in the case of having multiple head assemblies 100, it can facilitate the coordination of multiple head assemblies 100, avoid ineffective and redundant movements caused by one head assembly 100 having to return along the original path and causing other head assemblies 100 to avoid, and can significantly improve the overall operating efficiency of the chemical mechanical polishing equipment. Embodiments of multiple head assemblies 100 are described in detail below.

[0047] To further ensure the precise alignment of the head assembly 100 with the loading and unloading cup 60 during the processing, in a preferred embodiment, pressure sensors are provided on the sides of the first stop block 721 and the second stop block 722 facing each other, and the pressure sensors are communicatively connected to the driving device 110; the pressure sensors are configured to emit a hard limit signal when detecting the pressure applied by a swing limiting member (such as a movable limit block 723 or a limit swing rod 725), and the driving device 110 drives the head assembly 100 to slide to the initial position in a direction opposite to the previous driving and at a speed lower than the previous driving speed based on the received hard limit signal. Thus, when the head assembly 100 exceeds the initial position due to inertia or other reasons, it can be finely adjusted back to the initial position by the driving device 110, and the lower speed during fine adjustment can ensure that the head assembly 100 stops stably and accurately at the initial position.

[0048] In another embodiment, a distance measuring sensor is disposed on a side surface of one of the first stopper 721 and the second stopper 722 facing the swing limiting member (such as the movable limiting block 723 or the limiting swing rod 725). The distance measuring sensor is communicatively connected to the driving device 110. The distance measuring sensor is configured to detect a detection distance between the distance measuring sensor and the limiting portion 111 when the limiting portion 111 is limited between the first stopper 721 and the second stopper 722, and issue an offset signal when the detection distance is greater than the distance between the distance measuring sensor and the limiting portion 111 when the limiting portion 111 is at the original position. The driving device 110 drives the head assembly 100 to slide to the initial position at a speed lower than the speed of the previous drive based on the offset signal. In this embodiment, even if hard limiting does not occur, the limiting portion 111 can be controlled to return to the original position when the limiting portion 111 is offset, so that the head assembly 100 returns to the initial position, ensuring accurate alignment between the head assembly 100 and the loading and unloading cup 60.

[0049] Figure 7 shows Figure 3 a cross-sectional view taken along line B-B in Figure 5 and Figure 7 it can be seen that the annular track 71 includes a first loop 711 and a second loop 712 that are concentric and have different radii. The provision of two loops can increase the stability of the head assembly 100. The arc track 724 is disposed radially outside the annular track 71 and has a radius greater than that of the second loop 712. The upper end of the driving device 110 is provided with a first slider 1101, a second slider 1102, a third slider 1103, and a fourth slider 1104. The first slider 1101 and the second slider 1102 are slidably connected to the first loop 711, and the third slider 1103 and the fourth slider 1104 are slidably connected to the second loop 712. From Figure 7 it can be seen that the limiting portion 111 protrudes from the driving device 110, and the protruding direction is radially outward along the annular track 71. The movable limiting block 723 is slidably connected to the arc track 724, and the movable limiting block 723 extends downward to partially overlap the limiting portion 111 in the vertical direction, so as to be able to perform movable limiting on the limiting portion 111.

[0050] In the case where the chemical mechanical polishing equipment includes more than two head assemblies 100, a limiting component corresponding to each head assembly 100 is provided on the lower surface of the top plate 70. The horizontal position of the overlapping portion of the swing limiting member of each limiting component and the limiting portion 111 matches the horizontal distance from which the limiting portion 111 of the corresponding head assembly 100 protrudes from the driving device 110, and the vertical position where the overlapping portion of the swing limiting member of each limiting component and the limiting portion 111 is located matches the vertical distance from the upper end of the driving device 110 of the limiting portion 111 of the corresponding head assembly 100. The "overlapping portion" is the portion that contacts the limiting portion 111 for stopping, and the "overlapping portion of the swing limiting member and the limiting portion 111" is inFigures 3 - 5 In the illustrated embodiment, it refers to the overlapping portion of the movable limiting block 723 and the limiting portion 111 in the vertical direction. In Figure 6 the illustrated embodiment, it refers to the overlapping portion of the limiting post 727 and the limiting portion 111 in the vertical direction. The horizontal distance that the limiting portion 111 of a head assembly 100 protrudes from the driving device 110 and the vertical distance from the top end of the driving device 110 are respectively greater than or less than those of the limiting portion 111 of another head assembly, so that the head assembly 100 will not be interfered by the limiting components of other head assemblies 100 when sliding along the annular track 71.

[0051] Figure 8 shows a plurality of head assemblies 100 adopting Figures 3 - 5 the setting manner of the limiting components when using the illustrated limiting components. The driving devices 110 and the carrier heads 10 of two head assemblies 100 are placed in an overlapping position for facilitating the observation of the dimensions of structures such as the limiting components. The lower surface of the top plate 70 is provided with limiting components corresponding to the head assemblies 100 one by one; the radius of the arc track 724 of each limiting component matches the horizontal distance that the limiting portion 111 of its corresponding head assembly 100 protrudes from the driving device 110, and the length that the movable limiting block 723 of each limiting component extends downward matches the vertical position of the limiting portion 111 of its corresponding head assembly 100. In this embodiment, the radius of the arc track 724 corresponds to the horizontal position of the movable limiting block 723. The limiting components of the head assembly 100 and the limiting portion 111 of the driving device 110 that are blocked in the figure are shown by dashed lines. It can be seen that the horizontal distance that the limiting portion 111 shown by the dashed line protrudes from the driving device 110 and the length that the movable limiting block 723 of the corresponding limiting component extends downward are respectively greater than those of the limiting portion 111 of the head assembly 100 shown by the solid line and the length that the movable limiting block 723 of the corresponding limiting component extends downward. Thus, it can be ensured that a head assembly 100 will not be interfered by the limiting components of other head assemblies 100 when sliding along the annular track 71. Optionally, in order to avoid interference and simplify the structure, the limiting portion of each head assembly is configured to be telescopable in or out or movable up and down. Specifically, in an embodiment where the chemical mechanical polishing equipment includes more than two head assemblies, the lower surface of the top plate 70 is provided with limiting components corresponding to the head assemblies 100 one by one. Each limiting component has the same size and is arranged at intervals on the same circumference. The limiting portion 111 of each head assembly 100 is configured to be telescopable in or out or movable up and down to retract inward or move downward for avoidance when passing by the limiting components that do not correspond to it, and to extend outward or move upward for limiting when passing by the limiting components that correspond to it. The head assembly 100 and its corresponding limiting component can be communicatively connected or provided with other mutually inductive devices to mutually induct when approaching each other, so as to prompt the expansion and contraction or movement of the limiting portion 111.

[0052] When the limiting components shown are adopted in multiple head components 100 Figure 6 When the limiting components shown are adopted in multiple head components 100, the overlapping part of the swing limiting member and the limiting portion 111 is the contacting and overlapping part of the limiting post 727 and the limiting portion 111. Since the position of the limiting post 727 can be changed along the length direction of the limiting swing rod 725 and no longer has to be between the first stop block 721 and the second stop block 722, the position of the limiting post 727 is decoupled from the positions of the first stop block 721 and the second stop block 722. Thus, the distances of the first stop block 721 and the second stop block 722 of the limiting components corresponding to the multiple head components 100 from the center of the annular track 71 can be the same, that is, they are arranged on different arcs of a circle with the same radius. The sizes of the limiting swing rods 725 of the corresponding limiting components can also be designed to be the same, and the swing shafts 726 are arranged at the same radial position. Only the position of the limiting post 727 on the limiting swing rod 725 and the distance that the limiting post 727 protrudes downward are used to respectively match the limiting portions 111 of different head components 100 to form swing limiting. In this way, except for the limiting post 727, the other structures of the limiting components corresponding to the multiple head components can have the same size and be evenly distributed on a circle concentric with the annular track 71, making the distribution of the gravity of the limiting components on the top plate 70 more uniform, avoiding deformation and skew caused by uneven force on the top plate when different limiting components are arranged at different radial positions, which affects the levelness of the annular track and further affects the sliding or machining feed accuracy of the head component 100 during the polishing operation.

[0053] For an embodiment such as Figure 2 shown, which has two polishing discs 20 and three head components 100, an exemplary polishing run-in process is described in Figures 9 - 15 where small circles numbered 1, 2, and 3 represent the first head component 1001, the second head component 1002, and the third head component 1003 respectively. The first polishing disc 201, the second polishing disc 202, the first loading and unloading cup 601, the second loading and unloading cup 602, and the moisture preservation cup 603 are also marked in the figure. The arrow in the figure indicates the direction in which the first head component 1001 will move next. Specifically, an exemplary polishing run-in process can be as follows: (1) As shown in Figure 9 , the first head component 1001, the second head component 1002, and the third head component 1003 are respectively at their initial positions, that is, at the first loading and unloading cup 601, the second loading and unloading cup 602, and the moisture preservation cup 603. The first head component 1001 picks up the wafer W from the first loading and unloading cup 601, and at the same time or subsequently, the second head component 1002 picks up the wafer W from the second loading and unloading cup 602; (2) As shown in Figure 10 , the first head component 1001 moves clockwise to the first polishing disc 201 for rough polishing of the wafer W; (3) As shown in Figure 11, after rough polishing, the first head assembly 1001 further moves clockwise to the second polishing disc 202 for fine polishing of the wafer W. Meanwhile, the second head assembly 1002 can move clockwise to the first polishing disc 201 for rough polishing, and the third head assembly 1003 can move clockwise to the second loading and unloading cup 602 to load the wafer W; (4) As Figure 12 , after the first head assembly 1001 finishes fine polishing at the second polishing disc 202, it continues to move clockwise back to the first loading and unloading cup 601 to unload the wafer W. After the second head assembly 1002 finishes rough polishing while carrying the wafer W, it can continue to move clockwise to the second polishing disc 202 for fine polishing of the wafer W. The third head assembly 1003 can carry the wafer W and move clockwise to the first polishing disc 201 for rough polishing; (5) As Figure 13 , after the second head assembly 1002 finishes fine polishing, it moves clockwise back to the second loading and unloading cup 602 to unload the wafer W. At this point, both the first head assembly 1001 and the second head assembly 1002 complete the polishing of one wafer W after sliding one full circle along the annular track 71 clockwise. The first head assembly 1001 and the second head assembly 1002 respectively pick their next wafers W at the first loading and unloading cup 601 and the second loading and unloading cup 602; (6) As Figure 14 , the third head assembly 1003 moves counterclockwise to the second polishing disc 202 for fine polishing, the second head assembly 1002 moves counterclockwise to the first polishing disc 201 for rough polishing, and the first head assembly 1001 moves to the moisturizing cup 603 for moisture caching and waiting for polishing; (7) As Figure 15 , the third head assembly 1003 then moves clockwise to the second loading and unloading cup 602 to unload the wafer W. At this point, the third head assembly 1003 completes the polishing of one wafer W. The subsequent polishing and running process of the wafers will not be elaborated further. It should be understood that the above polishing process is merely a simple possible embodiment. In actual implementation, due to differences in the processing durations of rough polishing and fine polishing and other reasons, the coordination process among multiple polishing heads will be more complex. Each head assembly 100 may have one or more clockwise and counterclockwise reciprocating movement processes like the aforementioned third head assembly 1003 to cooperate with the movement paths of other head assemblies 100 to achieve efficient overall operation. Through the setting of the limiting components in this application, while ensuring the hard limit of the head assembly 100 and preventing entanglement of relevant cables and air pipes, the head assembly 100 can slide 360 degrees along the annular track 71 and return to its original position, reducing the situation of ineffective movement of the head assembly 100. It provides convenient, efficient, and diverse path selection for the polishing and running of the head assembly 100, especially multiple head assemblies 100, greatly promoting the efficient progress of the polishing process and significantly improving the wafer W processing efficiency of the chemical mechanical polishing equipment as a whole.

[0054] In addition, in existing chemical mechanical polishing equipment with a circular track, multiple head components on the circular track are usually fixed relative to each other and slide along the circular track together. In contrast, multiple head components in the present application are arranged to be relatively movable, thereby improving the flexibility of the movement of the multiple head components and facilitating efficient processing of the multiple head components at multiple polishing pads.

[0055] It should be understood that the first loading and unloading cup 601 is located at the initial position of the first head component 1001. However, this does not mean that the first loading and unloading cup 601 and the first head component 1001 can only interact one-to-one. The first loading and unloading cup 601 can also interact with the second head component 1002 and the third head component 1003. The first head component 1001 can also interact with the second loading and unloading cup 602 and the moisturizing cup 603. The same applies to other loading and unloading cups 60 or moisturizing cups 603 and head components 100.

[0056] Such as Figure 16 FIG. is a flowchart of a chemical mechanical polishing method according to an embodiment of the present application. The method includes the following steps: S1: Control the head component 100 to pick up the wafer W from the loading and unloading cup 60; S2: Drive the head component 100 to slide along the circular track 71 to the polishing pad 20 to polish the wafer W at the polishing pad 20; S3: After polishing, drive the head component 100 to slide back along the circular track 71 to the loading and unloading cup 60, and control the head component 100 to unload the polished wafer W to the loading and unloading cup 60; Among them, the direction in which the head component 100 carries the current wafer W and slides along the circular track 71 is opposite to the direction in which it carried the previous wafer W and slid along the circular track 71. It should be understood that for the case of multiple head components 100, this refers to the overall movement direction. For mutual cooperation, the head component 100 can reciprocally slide within a local range of the circular track 71.

[0057] In the case where the chemical mechanical polishing equipment includes a first polishing pad 201 and a second polishing pad 202, step S2 includes driving the head component 100 to slide along the circular track 71 to the first polishing pad 201 and the second polishing pad 202 in sequence for primary rough polishing and secondary fine polishing.

[0058] In the case where the chemical mechanical polishing equipment includes multiple head components 100, step S2 may further include one of the multiple head components 100 carrying the wafer W to move to the loading and unloading cup 60 or the moisturizing cup 603 for buffering and moisturizing to wait for the other head components 100 to finish polishing and vacate the polishing pad 20.

[0059] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The patent protection scope of the embodiments of the present application shall be defined by the claims.

Claims

1. A chemical mechanical polishing device for wafer processing, characterized in that: include: Polishing disc, A top plate located above the polishing disc, with a ring track provided on its lower surface; A head assembly, comprising a driving device and a carrier head connected to the lower end of the driving device, the carrier head is used to carry the wafer to the polishing plate for polishing, the upper end of the driving device is slidably mounted on the annular track to drive the head assembly to slide along the annular track, and the side of the driving device has a protruding limit portion; A limit assembly is provided on the lower surface of the top plate, which includes a first stop block and a second stop block arranged at intervals along an arc concentric with the annular track and a swing limit piece with a movable limit between the two. In the clockwise direction, the first stop block is located downstream of the second stop block, and the swing limit piece and the limit portion partially overlap in the vertical direction. The limit portion is limited by the first stop block in the clockwise direction and by the second stop block in the counterclockwise direction via the swing limit piece, so that the sliding range of the head assembly along the annular track is 360 to 380 degrees, so that the head assembly can return to the initial position in the clockwise or counterclockwise direction and interact with the interaction cup at the initial position in an aligned manner.

2. The chemical mechanical polishing equipment according to claim 1, characterized in that: The first stopper and the second stopper are arranged so that when the limiting portion is limited by the first stopper or the second stopper, the projections of the carrier head and the polishing disk on the horizontal plane do not overlap, so that the contaminants on the carrier head fall outside the polishing disk when limiting.

3. The chemical mechanical polishing equipment according to claim 2, characterized in that: The swing limiter includes an arc track concentric with the annular track and a movable limit block slidably mounted to the arc track, the first stop block and the second stop block are respectively arranged at two ends of the arc track, the movable limit block partially overlaps with the limit portion in the vertical direction, and the limit portion is limited by the first stop block in the clockwise direction and by the second stop block in the counterclockwise direction via the movable limit block.

4. The chemical mechanical polishing equipment according to claim 3, characterized in that: The movable limit block includes a first side toward the first stop block and a second side toward the second stop block; when the limiting portion moves clockwise, it can abut against the second side of the movable limit block and push the movable limit block to the first side of the movable limit block to abut against the first stop block, so as to be limited by the first stop block; when the limiting portion moves counterclockwise, it can abut against the first side of the movable limit block and push the movable limit block to the second side of the movable limit block to abut against the second stop block, so as to be limited by the second stop block.

5. The chemical mechanical polishing equipment according to claim 4, characterized in that: The planes where the first and second sides of the movable limit block are located extend radially along the annular track; the sides of the first stop block and the second stop block facing each other extend radially along the annular track; the two side surfaces against which the limiting portion abuts against the movable limit block match the shape of the movable limit block to form surface contact between the limiting portion and the movable limit block when the two abut against each other.

6. The chemical mechanical polishing equipment according to claim 1, characterized in that: The swing limiter includes a limit rocker arm longitudinally arranged between the first stop block and the second stop block, the first end of the limit rocker arm swings around the swing axis so that the second end thereof swings and limits between the first stop block and the second stop block, the swing axis is not on the arc where the first stop block and the second stop block are located, a limit column protruding downward is provided at a position of the limit rocker arm corresponding to the limit portion, the limit column partially overlaps with the limit portion in the vertical direction, and the limit portion is limited by the first stop block in the clockwise direction and by the second stop block in the counterclockwise direction via the limit column.

7. The chemical mechanical polishing equipment according to claim 1, characterized in that: The distance between the first stopper and the second stopper is set so that the sliding range of the limiting portion from the position limited by the first stopper to the position limited by the second stopper in a counterclockwise direction is 360 degrees to 380 degrees.

8. The chemical mechanical polishing equipment according to claim 1, characterized in that: The swing limiter is configured to magnetically repel the first stopper and the second stopper respectively to form a magnetic buffer limiter.

9. The chemical mechanical polishing device according to any one of claims 1 to 8, characterized in that: The driving device is configured to drive the head assembly to slide along the circular track and control the head assembly to stop at an initial position; when the head assembly is in the initial position, the limiting portion is located at an origin position between the first stop block and the second stop block, and the limiting portion is configured to be able to move 360 ​​degrees along the circular track to return to the origin position, so that the head assembly can slide 360 ​​degrees along the circular track to return to the initial position.

10. The chemical mechanical polishing equipment according to claim 9, characterized in that: The interaction cup includes a loading and unloading cup located below the head assembly; the loading and unloading cup is used to interact with the carrier head to provide wafers to the carrier head or receive wafers unloaded from the carrier head.

11. The chemical mechanical polishing equipment according to claim 10, characterized in that: The head assembly is configured to take a wafer from the loading and unloading cup, slide along the annular track to carry the wafer to the polishing plate for polishing, and then continue to slide along the annular track in the same sliding direction back to the loading and unloading cup to unload the wafer.

12. The chemical mechanical polishing equipment according to claim 9, characterized in that: The sides of the first stop block and the second stop block facing each other are provided with pressure sensors, and the pressure sensors are communicatively connected to the driving device; the pressure sensors are configured to send a hard limit signal when the pressure applied by the swing limit member is detected, and the driving device drives the head assembly to slide to the initial position in the opposite direction and at a speed lower than the previous drive based on the reception of the hard limit signal.

13. The chemical mechanical polishing equipment according to claim 9, characterized in that: A distance measuring sensor is provided on the side of one of the first stop block and the second stop block facing the swing limiter, and the distance measuring sensor is communicatively connected with the driving device; the distance measuring sensor is configured to detect a detection distance between the distance measuring sensor and the limiter when the limiter is limited between the first stop block and the second stop block, and to send an offset signal when the detection distance is greater than the distance between the distance measuring sensor and the limiter when the limiter is located at the origin position; the driving device drives the head assembly to slide to the initial position at a speed lower than the speed of the previous drive based on the offset signal.

14. The chemical mechanical polishing device according to any one of claims 1 to 8, characterized in that: The chemical mechanical polishing device comprises more than two head assemblies, and the lower surface of the top plate is provided with limit assemblies corresponding to the head assemblies one by one; the horizontal position of the part where the swing limit piece of each limit assembly overlaps with the limit part matches the horizontal distance where the limit part of the corresponding head assembly protrudes from the driving device, and the vertical position of the part where the swing limit piece of each limit assembly overlaps with the limit part matches the vertical distance between the limit part of the corresponding head assembly and the upper end of the driving device; The horizontal distance that the limiting portion of one head assembly protrudes from the driving device and the vertical distance from the upper end of the driving device are respectively greater than or smaller than the horizontal distance that the limiting portion of another head assembly protrudes from the driving device and the vertical distance from the upper end of the driving device, so that the head assembly is not interfered by the limiting components of other head assemblies when sliding along the annular track.

15. The chemical mechanical polishing device according to any one of claims 1 to 8, characterized in that: The chemical mechanical polishing equipment includes more than two head assemblies, and the lower surface of the top plate is provided with limit assemblies corresponding to the head assemblies one by one; each limit assembly has the same size and is arranged at intervals on the same circumference; the limit part of each head assembly is configured to be retractable inward and outward or movable up and down, so that when passing through a limit assembly that does not correspond to it, it can shrink or move downward to avoid it, and when passing through a limit assembly that corresponds to it, it can extend or move upward to limit it.

16. The chemical mechanical polishing equipment according to claim 14, characterized in that: The chemical mechanical polishing equipment comprises three head assemblies, two polishing discs and three interactive cups; the three head assemblies are respectively a first head assembly, a second head assembly and a third head assembly, and the three can move relatively; the two polishing discs are a rough polishing disc and a fine polishing disc; the three interactive cups are respectively a first loading and unloading cup, a second loading and unloading cup and a moisturizing cup located at the initial positions of the first head assembly, the second head assembly and the third head assembly; each head assembly moves to the rough polishing disc and the fine polishing disc in turn to polish the wafer; Each head assembly is configured to be able to slide 360 ​​to 380 degrees along the circular track, and one or more of the three head assemblies slide back and forth within a local range of the circular track to cooperate with the sliding of other head assemblies during the process of sliding one circle along the circular track to polish the wafer.

17. A chemical mechanical polishing method, used in the chemical mechanical polishing equipment according to any one of claims 1 to 16, characterized in that: The method comprises: Controlling the head assembly to take the wafer from the loading and unloading cup; Driving the head assembly to slide along the annular track to the polishing plate to perform wafer polishing at the polishing plate; After polishing, the head assembly is driven to slide along the annular track back to the loading and unloading cup, and the head assembly is controlled to unload the polished wafer into the loading and unloading cup; The direction in which the head assembly carries the current wafer to slide along the circular track is opposite to the direction in which the head assembly carries the previous wafer to slide along the circular track.

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