Anti-drip lifting mechanism, chemical mechanical polishing unit and chemical mechanical polishing equipment

Abstract

The present application provides a droplet-proof lifting mechanism, a chemical mechanical polishing unit and a chemical mechanical polishing device. The droplet-proof lifting mechanism includes a sleeve, a guide sleeve and a lifting rod arranged in sequence from the outside to the inside. The upper end of the lifting rod is fixedly connected to the top surface of the sleeve, driving the sleeve to rise and fall synchronously. The outer surface of the guide sleeve is provided with a plurality of blocking blocks at intervals and staggered thereon, which are used to block droplets from entering the upper surface of the guide sleeve along the gap between the sleeve and the guide sleeve and guide the droplets to flow down along at least one surface of the blocking blocks; thereby effectively blocking droplets from entering the interior of the lifting mechanism, reducing maintenance and cleaning costs, preventing downtime maintenance caused by damage to the lifting mechanism, and improving wafer production efficiency and yield.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing equipment, and in particular to a droplet-proof lifting mechanism, a chemical mechanical polishing unit, and a chemical mechanical polishing device. Background Art

[0002] Chemical Mechanical Polishing (CMP) is a method for achieving global planarization in integrated circuit manufacturing. Large quantities of polishing fluid and water are used during the chemical polishing process. The centrifugal force generated by the rotation of moving components, such as the polishing head and polishing disk, propels the fluid toward the periphery of the polishing disk. This splattering of the polishing fluid spreads throughout the polishing chamber, making it difficult to completely clean. Furthermore, the polishing fluid crystallizes into particles within the polishing chamber. Even tiny particles can become a source of contamination in the entire working environment, potentially scratching the wafer surface and reducing wafer yield.

[0003] Prior art has proposed a lifting ring to block liquid. The ring is installed on a lifting mechanism, which drives the ring to rise above the polishing plate during chemical mechanical polishing. However, this brings a new problem: a large amount of liquid adheres to the lifting mechanism and enters the lifting mechanism as it rises and falls, affecting its operation. Summary of the Invention

[0004] The embodiments of the present application provide a droplet-proof lifting mechanism, a chemical mechanical polishing unit, and a chemical mechanical polishing device, which aim to solve at least one of the technical problems existing in the prior art.

[0005] An embodiment of the present application provides a droplet-proof lifting mechanism, comprising a sleeve, a guide sleeve and a lifting rod arranged in sequence from the outside to the inside, the upper end of the lifting rod being fixedly connected to the top surface of the sleeve, driving the sleeve to rise and fall synchronously, and a plurality of blocking blocks are arranged at intervals and in an alternating manner on the outer surface of the guide sleeve, which are used to prevent droplets from entering the upper surface of the guide sleeve along the gap between the sleeve and the guide sleeve and to guide droplets to flow down along at least one surface of the blocking block.

[0006] In one embodiment, the blocking blocks are arranged in multiple layers, the blocking blocks in each layer are at the same height, and the blocking blocks in two adjacent layers are staggered in a direction along the outer surface of the guide cylinder.

[0007] In one embodiment, the blocking block includes a top surface, two side surfaces, a bottom surface and a front surface, and the top surface includes a first downward slope surface with a certain arc or angle from the middle to the two side surfaces, which is used to guide the droplets on the top surface to flow downward obliquely.

[0008] In one embodiment, each of the two side surfaces includes a second slope surface that is downward in a certain arc or angle toward the middle of the bottom surface, for guiding the liquid droplets on the two side surfaces to flow downward obliquely.

[0009] In one embodiment, the bottom surface includes a third downward sloped surface with a certain arc or angle from the middle to the two side surfaces, so as to guide the liquid droplets on the lower surface to flow downward obliquely.

[0010] In one embodiment, the blocking blocks of the two adjacent layers are staggered in a direction along the outer surface of the guide tube, including that the droplets flowing obliquely along the second slope surface or the third slope surface of the blocking block of the upper layer gather at the intersection of the second slope surface and the third slope surface and then drip downward onto the first slope surface of the blocking block of the next layer.

[0011] In one embodiment, the upper surface of the guide tube includes a fourth downward sloped surface with a certain arc or angle from the center to the outer surface, which is used to guide the droplets on the upper surface of the guide tube to flow obliquely downward; the edge of the upper surface of the guide tube includes a plurality of drainage grooves arranged at intervals, and the bottom surface of the drainage groove is consistent with the outer surface of the guide tube in the vertical direction, and the distance between the surface of the spacing portion between the plurality of drainage grooves and the inner wall of the sleeve is greater than the distance between the front face of the blocking block and the inner wall of the sleeve.

[0012] Another embodiment of the present application provides a chemical mechanical polishing unit, comprising a carrier head, a polishing disc, a polishing pad, a dressing device, a polishing liquid supply device and a plurality of anti-drip lifting mechanisms provided by any of the aforementioned embodiments, wherein the plurality of anti-drip lifting mechanisms are arranged at equal intervals on the periphery of the circumference of the polishing disc, and a retaining ring surrounding the polishing disc is commonly installed on the sleeves of the plurality of anti-drip lifting mechanisms; when the chemical mechanical polishing unit uses the carrier head, the polishing disc, the polishing pad, the dressing device and the polishing liquid supply device to perform polishing and cleaning operations, the lifting rods of the plurality of anti-drip lifting mechanisms rise synchronously, so that the retaining ring is higher than the polishing disc, so as to prevent the liquid on the polishing disc from splashing around; the retaining ring is configured not to affect the polishing and cleaning operations.

[0013] Another embodiment of the present application provides a chemical mechanical polishing device, comprising the chemical mechanical polishing unit provided in the aforementioned embodiment, wherein the chemical mechanical polishing unit is used to perform chemical mechanical polishing on a wafer.

[0014] In one embodiment, the chemical mechanical polishing equipment also includes a loading and unloading part, and the carrying head moves between a polishing position and an interaction position, the polishing position is a position for performing polishing and cleaning operations, and the polishing position is above the polishing disk; the interaction position is a position for interacting the wafer with the loading and unloading part, and the interaction position is outside the retaining ring.

[0015] The beneficial effects of the embodiments of the present application include: effectively preventing droplets from entering the interior of the lifting mechanism, reducing maintenance and cleaning costs, preventing downtime maintenance caused by damage to the lifting mechanism, and improving wafer production efficiency and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram of the polishing unit and the loading and unloading part in the chemical mechanical polishing equipment in the prior art.

[0018] Figure 2 yes Figure 1 Schematic diagram of the lifting mechanism and retaining ring of the middle polishing unit in the low and high positions.

[0019] Figures 3 to 5 yes Figure 2 Schematic diagram of droplets gathering and entering the interior of the lifting mechanism during repeated lifting.

[0020] Figure 6 It is a structural schematic diagram of the anti-drip lifting mechanism of the present application.

[0021] Figure 7 yes Figure 6 Schematic diagram of the middle anti-drip lifting mechanism sleeve when it is raised.

[0022] Figure 8 yes Figure 6 Schematic diagram of the three-dimensional structure of the guide cylinder of the anti-drip lifting mechanism.

[0023] Figure 9 yes Figure 6 Schematic diagram of the longitudinal section of the middle anti-drip lifting mechanism.

[0024] Figure 10 yes Figure 6 Front view of the blocking block of the middle anti-drip lifting mechanism.

[0025] Figure 11 yes Figure 6Schematic diagram of the anti-droplet lifting mechanism blocking and diverting droplets.

[0026] Reference numerals :

[0027] 100-polishing unit; 200-loading and unloading part; 400-retaining ring;

[0028] 10-carrying head; 20-polishing disc; 30-polishing pad; 40-dressing device; 41-dressing arm; 42-dressing head; 50-polishing liquid supply device; 60-droplet; 70-liquid

[0029] 300 - Existing lifting mechanism; 310 - Sleeve; 320 - Guide cylinder; 321 - Stopper; 322 - Top surface of stopper; 322a, 322b - First sloped surface; 323, 324 - Side surfaces of stopper; 323a, 324a - Second sloped surface; 325 - Bottom surface of stopper; 325a, 325b - Third sloped surface; 326 - Front surface of stopper; 327 - Top surface of guide cylinder; 328 - Drainage groove; 329 - Spacer; 330 - Lifting rod;

[0030] 1000-Chemical mechanical polishing unit of this application; 3000-Anti-drip lifting mechanism of this application. DETAILED DESCRIPTION

[0031] 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 drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present application.

[0032] In the description of this application, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0033] In addition, in the description of this application, unless otherwise specified and limited, it should be noted that the terms "install", "connect" and "connect" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0034] Figure 1 1 is a schematic diagram showing the positions of a polishing unit 100 and a loading and unloading portion 200 in a conventional chemical mechanical polishing device. The loading and unloading portion 200 is disposed adjacent to the polishing unit 100 to facilitate the transfer of wafers.

[0035] The polishing unit 100 includes a carrier head 10, a polishing disk 20, a polishing pad 30, a dressing device 40 and a polishing liquid supply device 50; the polishing pad 30 is arranged on the upper surface of the polishing disk 20 and rotates therewith; the horizontally movable carrier head 10 is arranged above the polishing pad 30, and the lower surface of the carrier head 10 attracts the wafer to be polished; 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 spreads 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 to be polished to the surface of the polishing pad 30, and the polishing liquid is distributed between the polishing pad 30 and the wafer, completing the removal of the wafer surface material under the action of chemical machinery.

[0036] In chemical mechanical polishing, the operation process of each wafer mainly includes:

[0037] 1) Wafer suction process: the carrier head 10 moves to the top of the loading and unloading part and then sucks the wafer placed on the loading and unloading part to the bottom of the carrier head 10;

[0038] 2) Polishing process: the wafer is loaded onto the polishing pad by the carrier head 10 for polishing;

[0039] 3) Wafer unloading process: After polishing is completed, the wafer is transported back by the carrier head 10 and unloaded onto the loading and unloading part.

[0040] During the polishing operation, the liquid on the polishing disk is thrown toward the periphery of the polishing disk by the centrifugal force generated by the rotation of moving parts such as the polishing head and the polishing disk. The thrown-out liquid includes not only polishing liquid and water containing a variety of chemical solutions and abrasive particles, but also impurities such as metal ions, silicon or silicon oxide particles generated during the polishing process. These are highly corrosive and easily form crystals, making them difficult to clean and easily damaging the wafer.

[0041] In order to prevent the liquid thrown from the polishing disc from causing pollution, such as Figure 2As shown, the polishing unit 100 also includes a lifting mechanism 300 and a retaining ring 400 fixedly mounted on the lifting mechanism 300. The lifting mechanism 300 is a columnar structure as a whole. A plurality of lifting mechanisms 300 are evenly spaced and distributed on the outer circumference of the polishing disc 20 to jointly support and drive the retaining ring 400 to rise and fall. During the film suction and unloading process, the lifting mechanism 300 drives the retaining ring 400 to a low position, as shown by the solid line. When in the low position, the upper end surface of the retaining ring 400 is not higher than the surface of the polishing disc 20, and will not interfere with the movement of the carrier head, etc.; during the polishing process, the lifting mechanism 300 drives the retaining ring 400 to a high position, as shown by the dotted line. When in the high position, the lower end surface of the retaining ring 400 is not higher than the surface of the polishing disc 20, forming a barrier to the liquid thrown out of the polishing disc.

[0042] The lifting mechanism 300 includes a sleeve 310, a guide sleeve 320, a lifting rod 330, and a cylinder 340 (not shown). The sleeve 310 is fixedly connected to the retaining ring 400. The guide sleeve 320 and the cylinder 340 are fixedly mounted on the platform where the polishing unit 100 is located. The guide sleeve 320 has a hollow structure to accommodate the lifting rod 330. The lifting rod 330 passes through the hollow structure of the guide sleeve 320 and is fixedly connected to the top surface of the sleeve 310. Under the action of the cylinder 340, the lifting rod 330 extends and retracts along the hollow structure of the guide sleeve 320, driving the sleeve 310 to rise and fall. The sleeves 310 of multiple lifting mechanisms 300 rise synchronously to jointly drive the retaining ring 400 to a high position. The sleeves 310 of multiple lifting mechanisms 300 descend synchronously to jointly drive the retaining ring 400 to a low position.

[0043] like Figure 3 As shown, when the sleeve 310 of the lifting mechanism 300 rises, the guide cylinder 320 is exposed. On the one hand, the liquid ejected will collide with the surface of the guide cylinder 320 and splash everywhere. Some of the upwardly splashed droplets may directly enter the upper surface of the guide cylinder 320 through the gap between the sleeve 310 and the guide cylinder 320 and form adhesion. On the other hand, due to the viscosity of the chemical solution and the inter-impurity force, the small droplets splashed on the surface of the guide cylinder 320 are likely to remain on the surface of the guide cylinder 320 and form droplets 60 with strong adhesion. Figures 4 and 5 As shown, during the repeated lifting and lowering of sleeve 310, droplets adhering to the surface of guide cylinder 320 adhere to the inner wall of sleeve 310. As sleeve 310 rises, liquid 70 forms on the upper surface of guide cylinder 320, and then enters the hollow structure of guide cylinder 320 in the direction of the arrow. Once liquid 70 flows into the cylinder through the hollow structure of guide cylinder 320 and lifting rod 330, it will prevent the lifting rod 330 from being raised and lowered smoothly, and may even damage the cylinder. In addition, liquid that has entered the upper surface of guide cylinder 320 is difficult to clean and may form crystals on the upper surface of guide cylinder 320, the surface of the hollow structure, and the surface of the lifting rod, affecting the normal lifting and lowering of the sleeve. It may even collapse onto the polishing pad, causing scratches on the wafer surface and reducing the wafer yield.

[0044] In order to solve the above technical problems, Figures 6 to 9 As shown, the droplet-proof lifting mechanism 3000 disclosed in this application includes, arranged in order from the outside to the inside, a sleeve 310, a guide cylinder 320, a lifting rod 330, and a cylinder 340 (not shown). The sleeve 310 is mounted on the outside of the guide cylinder 320. The guide cylinder 320 has a hollow structure to accommodate the lifting rod 330. The upper end of the lifting rod 330 extends beyond the upper surface of the guide cylinder 320 and is fixedly connected to the top surface of the sleeve 310. The guide cylinder 320 and the cylinder 340 are fixedly mounted on the machine platform where the lifting mechanism 3000 is located. Under the action of the cylinder 340, the lifting rod 330 extends and retracts along the hollow structure of the guide cylinder 320, driving the sleeve 310 to rise and fall.

[0045] In one embodiment, the outer surface of the guide tube 320 is provided with a plurality of blocking blocks 321, which are spaced and staggered along the outer surface of the guide tube 320 to prevent droplets from entering the upper surface of the guide tube 320 through the gap between the sleeve 310 and the guide tube 320. Specifically, the plurality of blocking blocks 321 are distributed in two directions: a first portion of blocking blocks 321 are spaced apart around the outer surface of the guide tube 320, and a second portion of blocking blocks 321 are vertically higher or lower than the first portion of blocking blocks 321 and spaced apart corresponding to the gaps between the first portion of blocking blocks 321, thereby forming a spaced and staggered maze structure. Preferably, the blocking blocks 321 are also configured to have a shape or structure that facilitates the flow of droplets adhering to the surface of the blocking blocks 321.

[0046] like Figure 7 and Figure 11As shown, when sleeve 310 rises, guide tube 320 is exposed. The ejected liquid collides with the surface of guide tube 320 and splashes in all directions. The upwardly splashing droplets are blocked by the spaced, staggered blocks 321, preventing them from continuing upward into the gap between sleeve 310 and guide tube 320. Furthermore, the ejected liquid will directly collide with the spaced, staggered blocks 321. Compared to the droplets that splash in all directions after colliding with the surface of guide tube 320, the droplets' splashing directions after colliding with the blocks 321 are more random and dispersed, making it difficult for them to form droplets 60 with strong adhesion on the surface of the blocks 321. Experimental results show that the majority of the droplets either land on the platform where the lifting mechanism 3000 is located, or flow down along the surface of the blocks 321 and the gaps between them, or along the surface of the guide tube 320 to the platform where the lifting mechanism 3000 is located, where they are then guided and collected. The remaining small portion of droplets primarily adheres to the surface of the guide tube 320 in the gaps between the blocks 321. Due to the presence of the blocking blocks 321, the distance between the inner wall of the sleeve 310 and the surface of the guide tube 320 at the gap between the blocking blocks 321 is greater. As the sleeve 310 repeatedly descends and ascends, droplets are less likely to adhere to the inner wall of the sleeve 310. In other words, compared to the prior art, this embodiment not only directly blocks upwardly splashing droplets, but also works by accelerating the downward discharge of droplets and reducing the "contact" area between the inner wall of the sleeve 310 and the surface of the guide tube 320. This reduces the possibility of droplets adhering to the sidewalls of the sleeve 310 during ascent and descent, effectively preventing droplets from entering the upper surface of the guide tube 320 as the sleeve 310 ascends.

[0047] In one embodiment, multiple layers of blocking blocks 321 are arranged at equal intervals along the vertical direction on the surface of the guide cylinder 320. The blocking blocks 321 of each layer are at the same height and are arranged at intervals around the outer surface of the guide cylinder 320. The blocking blocks 321 of two adjacent layers are staggered along the direction of the outer surface of the guide cylinder 320. Preferably, Figures 6 to 8 As shown, four layers of blocking blocks 321 are vertically arranged on the surface of the guide cylinder 320. The blocking blocks 321 in each layer are at the same height and are spaced apart around the outer surface of the guide cylinder 320. The positions of the blocking blocks 321 in the first and third layers are completely aligned along the outer surface of the guide cylinder 320. The positions of the blocking blocks 321 in the second and fourth layers are also completely aligned along the outer surface of the guide cylinder 320. The blocking blocks 321 in the second layer are aligned along the outer surface of the guide cylinder 320 and completely cover the gaps between the blocking blocks 321 in the first layer. As a result, the four layers of blocking blocks 321 together form an interlaced maze structure, which provides a better barrier against upwardly splashing droplets.

[0048] In one embodiment, Figure 10As shown, the blocking block 321 includes a top surface 322, two side surfaces 323 and 324, a bottom surface 325, and a front surface 326. The top surface 322 includes a first sloped surface 322a and a first sloped surface 322b, which extend downward from the center toward the two side surfaces 323 and 324 at a certain arc or angle. When splashing droplets adhere to or flow onto the top surface 322, the shape of the top surface 322 facilitates guiding the droplets to flow down along the first sloped surfaces 322a and 322b. Preferably, the first sloped surface 322a connects to the side surface 323, and the first sloped surface 322b connects to the side surface 324. There is a curved surface between the first sloped surfaces 322a and 322b that is higher in the middle and lower on both sides.

[0049] In one embodiment, both the side surface 323 and the side surface 324 include second sloped surfaces 323a and 324a that are downwardly oriented at a certain arc or angle toward the middle of the bottom surface 326. When splashing droplets adhere to or flow onto the side surface 323 or the side surface 324, their shape facilitates guiding the droplets to flow obliquely down along the second sloped surface 323a or 324a. Preferably, the second sloped surface 323a is connected to the first sloped surface 322a by a section of an arcuate surface, and the second sloped surface 324a is connected to the first sloped surface 322b by a section of an arcuate surface. The droplets that flow obliquely down along the first sloped surfaces 322a and 322b are further guided by the second sloped surfaces 323a and 324a and flow obliquely down along the second sloped surfaces 323a and 324a.

[0050] In one embodiment, the bottom surface 325 includes third sloped surfaces 325a and 325b that extend downward from the center to the two side surfaces 323 and 324 at a certain arc or angle. When splashing droplets adhere to the bottom surface 325, the shape of the bottom surface 325 facilitates guiding the droplets to flow down along the third sloped surfaces 325a and 325b. Preferably, the third sloped surface 325a is connected to the second sloped surface 323a, and the third sloped surface 325b is connected to the second sloped surface 324a. The third sloped surfaces 325a and 325b include a curved surface that is higher in the middle and lower on both sides. Droplets flowing down along the second or third sloped surface converge at the intersection of the second and third sloped surfaces.

[0051] In one embodiment, for two adjacent layers of blocking blocks 321, liquid droplets attached to the blocking block 321 of the upper layer and flowing obliquely down along the first sloped surface 322a, first sloped surface 322b, second sloped surface 323a, second sloped surface 324a, third sloped surface 325a, or third sloped surface 325b converge at the intersection of the second and third sloped surfaces and then drip downward under the action of gravity. The blocking block 321 of the lower layer is configured so that its first sloped surface 322a or first sloped surface 322b directly faces and receives the droplets dripping from the blocking block 321 of the upper layer, guiding the droplets to continue their oblique downward flow. This configuration prevents the dripping droplets from splashing upward again and better guides the liquid downward.

[0052] In one embodiment, the upper surface 327 of the guide cylinder is tilted downward at a certain arc or angle from the center outward, so as to guide the droplets attached to or flowing to the upper surface 327 of the guide cylinder to flow obliquely downward. At the same time, a plurality of drainage grooves 328 are arranged at intervals on the edge of the upper surface 327 of the guide cylinder, and the bottom surface of the drainage groove 328 is vertically consistent with the outer surface of the guide cylinder 320; the spacers 329 between the drainage grooves 328 are higher than the bottom surface of the drainage grooves 328. Preferably, the drainage grooves 328 are opposite to the topmost layer of blocking blocks 321, the spacers are opposite to the gaps between the topmost layer of blocking blocks 321, and the distance between the spacers 329 and the topmost layer of blocking blocks 321 is less than the distance between the two layers of blocking blocks 321, which makes the spacers 329 play the role of a layer of blocking blocks. In addition, as Figure 9 As shown, the distance between the side surface of the spacer 329 and the inner wall of the sleeve 310 is set to be greater than the distance between the front surface 326 of the blocking block 321 and the inner wall of the sleeve 310, that is, the surface of the spacer 329 is farther from the inner wall of the sleeve 310 than the front surface 326 of the blocking block 321 is from the inner wall of the sleeve 310, which makes it easy for droplets to flow down obliquely once they adhere to the spacer 329.

[0053] In one embodiment, sleeve 310 and guide tube 320 are made of corrosion-resistant plastic, such as PP, PVDF, PTFE, PEEK, etc. Sleeve 310 and guide tube 320 are polished, and the smooth lower surface facilitates water flow. Optionally, the surfaces of sleeve 310 and guide tube 320 are covered with a hydrophilic material layer to further enhance water flow.

[0054] Another embodiment of the present application provides a chemical mechanical polishing unit 1000, comprising a carrier head 10, a polishing plate 20, a polishing pad 30, a dressing device 40, a polishing liquid supply device 50, and the anti-drip lifting mechanism 3000 of any of the aforementioned embodiments. The chemical mechanical polishing unit 1000 performs a wafer polishing operation, comprising: a polishing pad 30 disposed on the upper surface of the polishing plate 20 and rotating therewith; a horizontally movable carrier head 10 disposed above the polishing pad 30, with the wafer to be polished being attracted to its lower surface; a dressing device 40 comprising a dressing arm 41 and a dressing head 42, wherein 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; a polishing liquid supply device 50 to spread polishing liquid on the surface of the polishing pad 30; during the polishing operation, the carrier head 10 presses the surface of the wafer 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, completing the removal of material from the wafer surface under the action of chemical mechanical force. The chemical mechanical polishing unit 1000 also cleans the wafer, polishing head 10, and polishing pad 20. After polishing, a high-pressure nozzle sprays a large amount of deionized water to rinse the wafer, polishing head 10, and polishing pad 20 to remove impurities from their respective surfaces. Both polishing and cleaning operations typically take tens of seconds or even longer. During cleaning, water flow rates can reach tens of liters per minute to ensure effective cleaning. During both polishing and cleaning operations, the liquid on the polishing pad is continuously ejected toward the periphery of the polishing pad due to the centrifugal force generated by the rotation of the moving components, including the polishing head and polishing pad.

[0055] Multiple anti-drip lift mechanisms 3000 are arranged at equal intervals around the circumference of the polishing pad 20. A retaining ring 400 is mounted on the multiple sleeves 310 of the anti-drip lift mechanisms 3000, surrounding the polishing pad 20. During polishing and cleaning operations in the chemical mechanical polishing unit 1000, the lift rods 330 of the anti-drip lift mechanisms 3000 rise synchronously, pushing the sleeves 310 and retaining ring 400 upward. This elevates the retaining ring 400 above the polishing pad 20, preventing liquid from splashing outward.

[0056] In addition, the retaining ring 400 is configured to not affect the polishing and cleaning operations after it is raised. During the polishing and cleaning operations, not only does the dressing arm 41 of the dressing device 40 drive the dressing head 42 to swing, but the carrier head 10 also swings under the drive of a connecting arm; the polishing liquid supply device 50 is installed on another connecting arm, but the connecting arm of the polishing liquid supply device 50 may not swing, but remain in a fixed position. The position to which the retaining ring 400 rises cannot affect the swinging of the connecting arm 41 and the carrier head 10 during the polishing and cleaning operations, nor can it interfere with the connecting arm of the polishing liquid supply device 50. In one embodiment, the upper surface of the retaining ring 400 is provided with openings at the position where the connecting arm of the dressing arm 41 and the carrier head 10 swings and at the position of the connecting arm of the polishing liquid supply device 50. The retaining ring 400 of the chemical mechanical polishing unit 1000 of the present application does not affect the polishing and cleaning operations, and effectively prevents the liquid during the polishing and cleaning operations from splashing into the entire working environment to cause pollution; at the same time, the anti-droplet lifting mechanism 3000 of the present application is used to block and drain downward a large number of droplets splashed onto the surface of the guide cylinder 320, preventing the droplets from entering the interior of the lifting mechanism, reducing maintenance and cleaning costs, avoiding losses caused by downtime for maintenance, and effectively reducing the risk of damage to the wafer due to crystallization and collapse of droplets in the lifting mechanism.

[0057] Another embodiment of the present application provides a chemical mechanical polishing apparatus, comprising the chemical mechanical polishing unit 1000 of the aforementioned embodiment, configured to chemically mechanically polish wafers. The chemical mechanical polishing apparatus further includes a wafer post-processing unit configured to perform post-processing on the chemically mechanically polished wafers, including but not limited to cleaning and drying.

[0058] In one embodiment, the chemical mechanical polishing apparatus further includes a loading and unloading unit 200. In the chemical mechanical polishing apparatus, the carrier head 10 of the chemical mechanical polishing unit 1000 needs to continuously move between a polishing position, where polishing and cleaning operations are performed, and an exchange position, where wafers are exchanged with the loading and unloading unit 300. Preferably, the exchange position is outside the retaining ring 400. This effectively prevents the loading and unloading unit 200 from being attached to liquid on the polishing plate, thereby contaminating the wafers or even causing crystallization and damage.

[0059] The process of the loading and unloading part 200 and the chemical mechanical polishing unit 1000 in the chemical mechanical polishing equipment includes:

[0060] 1) During wafer suction operation, after the retaining ring 400 of the anti-drip lifting mechanism 3000 descends to a low position, the carrier head 10 moves to an interactive position to absorb the wafer from the loading and unloading portion 200. In the low position, the upper end surface of the retaining ring 400 is not higher than the surface of the polishing plate 20, and does not interfere with the movement of the carrier head 10;

[0061] 2) Polishing and cleaning operations: The carrier head 10 moves to the polishing position, and the retaining ring 400 of the anti-drip lifting mechanism 3000 rises to a high position to polish and clean the wafer. When in the high position, the lower end surface of the retaining ring 400 is not higher than the surface of the polishing plate 20, thereby blocking the liquid from being thrown off the polishing plate;

[0062] 3) Wafer unloading operation: After the polishing operation and cleaning are completed, the retaining ring 400 of the anti-drip lifting mechanism 3000 drops to a low position, and the carrier head 10 moves to the interactive position and unloads the wafer to the loading and unloading part 200.

[0063] The chemical mechanical polishing equipment of the present application does not require changes to the process flow. The anti-droplet lifting mechanism 3000 of the present application is used to block and drain downward a large number of droplets sputtered onto the surface of the guide tube 320, preventing downtime for maintenance caused by damage to the lifting mechanism, thereby improving wafer production efficiency and yield.

[0064] The above implementation methods are only used to illustrate the embodiments of the present application, and are not intended to limit the embodiments of the present application. Ordinary technicians in the relevant technical field can 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 fall within the scope of the embodiments of the present application, and the scope of patent protection of the embodiments of the present application should be defined by the claims.

Claims

1. A droplet-proof lifting mechanism, characterized in that: It includes a sleeve, a guide sleeve and a lifting rod arranged in sequence from the outside to the inside. The upper end of the lifting rod is fixedly connected to the top surface of the sleeve, and is used to drive the sleeve to rise and fall synchronously. The outer surface of the guide sleeve is provided with a plurality of blocking blocks at intervals and staggered. The blocking blocks are used to block the droplets from entering the upper surface of the guide sleeve along the gap between the sleeve and the guide sleeve and guide the droplets to flow down along at least one surface of the blocking blocks.

2. The anti-drip lifting mechanism according to claim 1, wherein: The blocking blocks are arranged in multiple layers, the blocking blocks in each layer are at the same height, and the blocking blocks in two adjacent layers are staggered in a direction along the outer surface of the guide cylinder.

3. The anti-drip lifting mechanism according to claim 2, wherein: The blocking block includes a top surface, two side surfaces, a bottom surface and a front surface. The top surface includes a first downward slope surface with a certain arc or angle from the middle to the two side surfaces, which is used to guide the droplets on the top surface to flow downward obliquely.

4. The anti-drip lifting mechanism according to claim 3, wherein: Each of the two side surfaces includes a second downward slope surface with a certain arc or angle toward the middle of the bottom surface, for guiding the liquid droplets on the two side surfaces to flow downward obliquely.

5. The anti-drip lifting mechanism according to claim 4, characterized in that: The bottom surface includes a third downward slope surface with a certain arc or a certain angle from the middle to the two side surfaces, which is used to guide the liquid droplets on the bottom surface to flow downward obliquely.

6. The anti-drip lifting mechanism according to claim 5, characterized in that: The staggering in the direction along the outer surface of the guide tube includes that the droplets flowing obliquely along the second slope surface or the third slope surface of the blocking block of the upper layer gather at the intersection of the second slope surface and the third slope surface and then drip down onto the first slope surface of the blocking block of the next layer.

7. The anti-drip lifting mechanism according to any one of claims 3 to 6, characterized in that: The upper surface of the guide tube includes a fourth downward slope surface with a certain arc or angle from the center to the outer surface, which is used to guide the droplets on the upper surface of the guide tube to flow downward obliquely; The edge of the upper surface of the guide cylinder includes a plurality of drainage grooves arranged at intervals, the bottom surface of the drainage groove is vertically consistent with the outer surface of the guide cylinder, and the distance between the surface of the spacing portion between the plurality of drainage grooves and the inner wall of the sleeve is greater than the distance between the front face of the blocking block and the inner wall of the sleeve.

8. A chemical mechanical polishing unit, characterized in that: The device comprises a carrier head, a polishing plate, a polishing pad, a dressing device, a polishing liquid supply device, and a plurality of anti-drip lifting mechanisms according to any one of claims 1 to 7, wherein the plurality of anti-drip lifting mechanisms are arranged at equal intervals around the circumference of the polishing plate, and a retaining ring surrounding the polishing plate is commonly mounted on the sleeves of the plurality of anti-drip lifting mechanisms; When the chemical mechanical polishing unit performs polishing and cleaning operations using the carrier head, the polishing plate, the polishing pad, the dressing device, and the polishing liquid supply device, the lifting rods of the plurality of anti-drip lifting mechanisms rise synchronously, so that the retaining ring is higher than the polishing plate, so as to prevent the liquid on the polishing plate from splashing around; The retaining ring is configured not to affect the polishing and cleaning operations.

9. A chemical mechanical polishing device, characterized in that: The chemical mechanical polishing unit according to claim 8 is used to perform chemical mechanical polishing on a wafer.

10. The chemical mechanical polishing equipment according to claim 9, wherein It also includes a loading and unloading part, and the carrying head moves between a polishing position and an interactive position. The polishing position is a position for performing polishing and cleaning operations, and the polishing position is above the polishing disk; the interactive position is a position for interacting with the wafer with the loading and unloading part, and the interactive position is outside the retaining ring.

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