A rotary joint of a double-sided polishing machine and a double-sided polishing machine

Abstract

The application relates to the technical field of semiconductor processing equipment, in particular to a rotary joint of a double-sided polishing machine. The static ring seat has two, each of which is annularly sleeved on a central shaft and fixedly connected with the central shaft; the static ring has two, each of which is annularly sleeved on the central shaft and fixedly connected with the static ring seat, and the two static rings are oppositely arranged; the shell is sleeved on the central shaft and located between the two static ring seats, rotationally connected with the two static ring seats so that the shell can rotate relative to the central shaft; the dynamic ring has two, which are sleeved on the central shaft and fixedly connected with the shell so that the dynamic ring can rotate with the shell; the dynamic ring and the static ring are one-to-one correspondingly arranged, and the end face of the dynamic ring close to the static ring is in abutting cooperation with the end face of the static ring close to the dynamic ring, so that two groups of sealing pairs are formed between the two groups of dynamic rings and static rings; wherein, an annular accommodating cavity is formed between the outer wall of the dynamic ring and the central shaft. The technical effect of improving the sealing performance of the rotary joint is achieved.

Description

Technical Field

[0001] This application relates to the field of semiconductor processing equipment technology, and in particular to a rotary joint for a double-sided polishing machine and the double-sided polishing machine itself. Background Technology

[0002] Double-sided polishing machines are high-precision equipment used in the processing of large-size silicon wafers to remove surface defects, reduce roughness, and obtain excellent flatness. They utilize the principle of chemical mechanical polishing, which achieves the polishing of silicon wafers through the chemical corrosion of polishing fluid and the mechanical removal of abrasive particles.

[0003] In the prior art, during the processing, a rotary joint is usually used to deliver external polishing fluid between the rotating upper and lower disks to achieve chemical etching of the silicon wafer during processing; however, small amounts of polishing fluid often leak from the rotary joint, and the leaked polishing fluid crystallizes, which in turn aggravates the wear of the sealing structure.

[0004] Therefore, the technical problem with the existing technology is that the rotary joint has low sealing performance. Summary of the Invention

[0005] This application provides a rotary joint for a double-sided polishing machine and a double-sided polishing machine. By using two sets of stationary rings and two sets of moving rings to form sealing pairs, the technical effect of improving the sealing performance of the rotary joint is achieved.

[0006] Firstly, the rotary joint of the double-sided polishing machine provided in this application adopts the following technical solution: A rotary joint for a double-sided polishing machine includes: a central shaft; a stationary assembly comprising: two stationary ring seats, each annularly sleeved on the central shaft and fixedly connected to the central shaft; two stationary rings, each annularly sleeved on the central shaft and fixedly connected to the stationary ring seat, with the two stationary rings arranged opposite to each other; and a rotating assembly comprising: a housing sleeved on the central shaft and located between the two stationary ring seats, the housing being rotatably connected to the two stationary ring seats so that the housing can be rotated relative to the central shaft. The central shaft rotates; there are two rotating rings, each sleeved on the central shaft and fixedly connected to the housing so that it can rotate with the housing; the rotating rings and stationary rings are arranged in a one-to-one correspondence, with the end face of the rotating ring near the stationary ring abutting against the end face of the stationary ring near the rotating ring, so that two sets of sealing pairs are formed between the two sets of rotating rings and stationary rings; wherein, an annular accommodating cavity is formed between the rotating rings and the outer wall of the central shaft; an input flow channel is opened in the central shaft, and the input flow channel communicates with the accommodating cavity; an output flow channel is opened on the housing, and the output flow channel communicates with the accommodating cavity.

[0007] Preferably, an annular transition cavity is formed between the two moving rings; the receiving cavity and the output flow channel are connected through the transition cavity.

[0008] Preferably, the rotating assembly further includes a spring disposed between the two moving rings, the two ends of the spring respectively abutting against the two moving rings to apply a preload force toward the corresponding stationary ring to the two moving rings.

[0009] Preferably, a spring channel is provided inside the housing, the spring channel is located between the two moving rings, and the spring channel is used to accommodate the spring; the spring channel is independently arranged from the accommodating cavity, the transition cavity and the output flow channel.

[0010] Preferably, a bearing is provided between the housing and the two stationary ring seats, and the housing is rotatably supported relative to the stationary ring seats by the bearing.

[0011] Preferably, the moving ring and / or the stationary ring are made of silicon carbide material.

[0012] Preferably, a first sealing element is provided between the central shaft and the stationary ring seat; a second sealing element is provided between the stationary ring seat and the stationary ring; and a third sealing element is provided between the moving ring and the housing.

[0013] Preferably, a gap space is formed between the housing and the moving ring, and the sealing pair is located within the gap space; the gap space is connected to the spring channel; two stationary ring seats are defined as a first stationary ring seat and a second stationary ring seat, the first stationary ring seat and / or the central shaft having a first water channel, and the second stationary ring seat and / or the central shaft having a second water channel; the first water channel, the gap space, the spring channel, and the second water channel are sequentially connected to form a flushing channel for removing leaked polishing fluid.

[0014] Preferably, the spring channel is provided in multiple ways, and the multiple spring channels are distributed circumferentially along the central axis.

[0015] Secondly, the double-sided polishing machine provided in this application adopts the following technical solution: A double-sided polishing machine having the aforementioned rotary joint.

[0016] In summary, this application includes at least one of the following beneficial technical effects: The rotating joint features a structure that combines stationary and rotating components, employing two sets of stationary rings and two sets of rotating rings to form sealing pairs. This design enhances the structural stability and sealing reliability of the rotary joint during operation. The stationary rings and their seats are fixed in place, while the rotating rings rotate synchronously with the housing. Combined with the ring-shaped cavity and independent input / output channels, this ensures stable delivery of the polishing fluid during rotation. The two symmetrically arranged sealing pairs effectively improve the pressure resistance and sealing performance of the sealing area, reducing polishing fluid leakage. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the polishing fluid supply for the rotary joint described in this application; Figure 2 This is a schematic diagram of the flushing flow channel of the rotary joint described in this application.

[0018] Explanation of reference numerals in the attached drawings: 100, central shaft; 110, input flow channel; 200, stationary component; 210, stationary ring seat; 211, first stationary ring seat; 212, second stationary ring seat; 213, spring channel; 220, stationary ring; 300, rotating component; 310, housing; 311, output flow channel; 313, gap space; 320, moving ring; 321, receiving cavity; 322, transition cavity; 330, spring. Detailed Implementation

[0019] The serial numbers assigned to components in this document, such as "first" and "second," are used solely to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used solely for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0020] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] To better understand the above technical solutions, a detailed description of the technical solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0022] Double-sided polishing machines rely on the principle of chemical mechanical polishing to complete the process. The chemical components in the polishing slurry etch the surface of the silicon wafer, while the abrasive particles inside the polishing slurry achieve mechanical removal. Through the synergy of chemical and mechanical action, the silicon wafer achieves a high-precision, low-defect surface quality.

[0023] In the continuous polishing process of silicon wafers, it is necessary to continuously, stably, and cleanly deliver external polishing slurry between the rotating upper and lower polishing discs to ensure a uniform and stable polishing process. The core component for achieving this delivery function is the polishing slurry supply rotary joint. The rotary joint needs to ensure smooth flow of polishing slurry while adapting to the continuous rotation of the polishing discs. Since silicon wafer processing has extremely high requirements for surface quality, any tiny particles, scratches, or impurities may cause the silicon wafer to be scrapped. Therefore, the polishing slurry supply rotary joint must have extremely high cleanliness, sealing, and stability.

[0024] In existing technologies, some double-sided polishing machines use rotary joints with soft sealing rings for dynamic sealing, which has significant defects during long-term operation. The polishing fluid contains fine abrasive particles, which continuously scour and wear down the soft sealing ring during the operation of the rotary joint, causing wear particles to form on the sealing ring. These wear particles, once inside the polishing fluid, directly scratch the silicon wafer surface or cause excessive particle counts. Furthermore, the polishing fluid itself has a tendency to crystallize. When a small leak occurs in the sealing structure, the leaked polishing fluid exposed to air will quickly crystallize, forming hard particles. These hard particles will also contaminate the polishing fluid and scratch the silicon wafer surface, severely affecting the silicon wafer yield. In addition, the internal structure of traditional rotary joints is relatively simple, lacking a structure for treating leaked polishing fluid and failing to provide a good lubrication environment for the sealing pair. This results in rapid wear of the sealing pair, short lifespan, and difficulty in meeting the cleanliness requirements of advanced processes.

[0025] To address the aforementioned issues, this application provides a rotary joint for a double-sided polishing machine. By optimizing the sealing structure, it fundamentally improves problems such as seal wear, polishing fluid leakage, and crystallization contamination, thereby increasing the service life and cleanliness level of the rotary joint and meeting the high-precision processing requirements of large-size silicon wafers.

[0026] This application provides a rotary joint for a double-sided polishing machine, such as... Figure 1As shown, the assembly includes a central shaft 100, a stationary component 200, and a rotating component 300. The stationary component 200 includes: two stationary ring seats 210, each annularly fitted onto the central shaft 100 and fixedly connected to the central shaft 100; and two stationary rings 220, each annularly fitted onto the central shaft 100 and fixedly connected to the stationary ring seat 210, with the two stationary rings 220 arranged opposite to each other. The rotating component 300 includes: a housing 310, fitted onto the central shaft 100 and located between the two stationary ring seats 210, rotatably connected to the two stationary ring seats 210 to allow the housing 310 to rotate relative to the central shaft 100. Two rotating rings 320 are provided, and the two rotating rings 320 are sleeved on the central shaft 100. The rotating rings 320 are fixedly connected to the housing 310 so that the rotating rings 320 can rotate with the housing 310. The rotating rings 320 and the stationary rings 220 are arranged in a one-to-one correspondence. The end face of the rotating ring 320 near the stationary ring 220 abuts against the end face of the stationary ring 220 near the rotating ring 320, so that two sets of sealing pairs are formed between the two sets of rotating rings 320 and stationary rings 220. An annular accommodating cavity 321 is formed between the rotating rings 320 and the outer wall of the central shaft 100. An input flow channel 110 is opened in the central shaft 100, and the input flow channel 110 communicates with the accommodating cavity 321. An output flow channel 311 is opened on the housing 310, and the output flow channel 311 communicates with the accommodating cavity 321.

[0027] Specifically, such as Figure 1 As shown, the rotary joint proposed in this application mainly comprises three parts: a central shaft 100, a stationary component 200, and a rotating component 300. The central shaft 100 is the core supporting component of the rotary joint, and has an overall shaft-like structure that extends axially, providing an installation base for the stationary component 200, the rotating component 300, and the internal flow channel. The stationary component 200 is fixedly connected to the central shaft 100 and does not rotate during operation. The rotating component 300 can rotate relative to the central shaft 100 and the stationary component 200 to adapt to the rotation state of the polishing disc of the double-sided polishing machine and achieve a stable supply of polishing fluid during rotation.

[0028] The stationary component 200 includes two stationary ring seats 210 and two stationary rings 220. There are two stationary ring seats 210, defined as a first stationary ring seat 211 and a second stationary ring seat 212. Both stationary ring seats 210 are ring-shaped and are respectively fitted outside the central shaft 100, and are fixedly connected to the central shaft 100, without relative rotation or axial movement. The two stationary ring seats 210 are distributed at intervals along the axial direction of the central shaft 100, providing installation space and rotational support foundation for the internal rotating component 300. Two stationary rings 220 are also provided, each stationary ring 220 having a ring structure and being fitted around the outside of the central shaft 100. The two stationary rings 220 are fixedly connected to the two stationary ring seats 210 respectively, and maintain a relative installation relationship. Relative installation means that the two stationary rings 220 are installed in positions close to each other on the stationary ring seats 210. The first stationary ring 220 is installed on the end face of the first stationary ring seat 211 near the second stationary ring seat 212, and the second stationary ring 220 is installed on the end face of the second stationary ring seat 212 near the first stationary ring seat 211, so that the two stationary rings 220 are arranged relative to each other in the axial direction, providing a stable sealing foundation for the subsequent mating and sealing of the rotating ring 320.

[0029] The rotating assembly 300 includes a housing 310 and two rotating rings 320. The housing 310 is sleeved outside the central shaft 100 and located between the two stationary ring seats 210. The housing 310 and the two stationary ring seats 210 are rotatably connected, so that the housing 310 can rotate smoothly and steadily relative to the central shaft 100. As the main structure of the rotating assembly 300, the housing 310 rotates synchronously with the polishing disc of the double-sided polishing machine during operation, ensuring that the supply of polishing fluid and the polishing action are synchronized.

[0030] Two rotating rings 320 are provided, both of which are annular in structure and fitted around the central shaft 100. The rotating rings 320 are fixedly connected to the housing 310, allowing them to rotate synchronously with the housing 310, preventing relative movement between them and ensuring the stability of the sealing structure. Each of the two rotating rings 320 corresponds to one of the two stationary rings 220, with each rotating ring 320 forming a mating relationship with its corresponding stationary ring 220. The end face of the rotating ring 320 near the stationary ring 220 abuts against the end face of the stationary ring 220 near the rotating ring 320, forming two sets of sealing pairs between the two sets of rotating rings 320 and stationary rings 220. These two sets of sealing pairs are symmetrically arranged along the central shaft 100, improving the overall sealing effect and structural stability. The central shaft 100, the rotating ring 320, and the stationary ring 220 are kept coaxial. Furthermore, the central shaft 100, the rotating ring 320, the stationary ring 220, the stationary ring seat 210, the housing 310, the first seal, the second seal, and the third seal are all kept coaxial to ensure uniform force and smooth operation during rotation, and to avoid increased wear or seal failure caused by eccentricity.

[0031] like Figure 1 As shown, inside the rotary joint, the rotating ring 320, the stationary ring 220, the stationary ring seat 210, and the outer wall of the central shaft 100 together form an annular accommodating cavity 321. The accommodating cavity 321 is used to contain the polishing fluid and provide a stable flow space for the polishing fluid. During the process of conveying the polishing fluid under pressure, a small amount of leakage will occur at the sealing pair position between the rotating ring 320 and the stationary ring 220. This leakage is a controllable leakage under normal working conditions.

[0032] An input channel 110 is provided inside the central shaft 100. The input channel 110 extends axially or radially along the central shaft 100 and communicates with the accommodating cavity 321 to introduce external polishing slurry into the accommodating cavity 321. An output channel 311 is provided on the housing 310, which also communicates with the accommodating cavity 321, allowing the polishing slurry inside the accommodating cavity 321 to be transported outward through the output channel 311. During operation, the polishing slurry is injected from the input channel 110 inside the central shaft 100, enters the annular accommodating cavity 321 through the input channel 110, and is then output from the output channel 311 on the housing 310 to the upper polishing disc position of the double-sided polishing machine. This provides a uniform supply to the silicon wafer area between the upper and lower polishing discs, providing a continuous and stable polishing slurry for the chemical mechanical polishing of the silicon wafer.

[0033] Furthermore, an annular transition cavity 322 is formed between the two moving rings 320; the receiving cavity 321 and the output flow channel 311 are connected through the transition cavity 322.

[0034] An annular transition cavity 322 is formed between the two moving rings 320. The transition cavity 322 is located on the side where the two moving rings 320 are close to each other and extends circumferentially along the central axis 100 to form a continuous annular space. The receiving cavity 321 and the output channel 311 are connected through the transition cavity 322. The polishing liquid enters the transition cavity 322 from the receiving cavity 321, then flows to the output channel 311 through the transition cavity 322, and finally exits from the output channel 311.

[0035] The transition cavity 322 allows for more uniform flow of polishing fluid within the cavity, resulting in lower flow resistance and preventing excessive local pressure that could increase leakage in the sealing pair. Simultaneously, the transition cavity 322 provides reasonable space for the moving ring 320 to move, allowing it a certain amount of axial float. This facilitates the installation of the moving ring 320 and ensures that the moving ring 320 and stationary ring 220 maintain a good fit, improving the self-adaptive capability of the sealing pair and reducing the risk of seal failure due to machining or assembly errors.

[0036] Bearings are installed between the housing 310 and the two stationary ring seats 210, providing rotational support for the housing 310 relative to the stationary ring seats 210. The inner ring of the bearing mates with the stationary ring seat 210, and the outer ring mates with the housing 310. This bearing support method results in low rotational resistance, smooth operation, and high precision for the housing 310, preventing radial runout or axial movement during rotation and ensuring a good seal between the rotating ring 320 and the stationary ring 220.

[0037] The bearing structure effectively reduces the frictional loss of the rotating component 300, reduces vibration and noise during rotation, improves the overall operational stability of the rotary joint, and provides a reliable guarantee for high-precision, long-term continuous operation.

[0038] Furthermore, such as Figure 2 As shown, the rotating assembly 300 also includes a spring 330, which is disposed between the two moving rings 320. The two ends of the spring 330 respectively abut against the two moving rings 320 to apply a preload force toward the corresponding stationary ring to the two moving rings 320.

[0039] A spring 330 is disposed between the two rotating rings 320, located within the transition cavity 322 region. Both ends of the spring 330 abut against the two rotating rings 320 respectively. In the assembled state, the spring 330 is in a compressed state, continuously applying an elastic preload to the two rotating rings 320. The preload is directed axially outward along the central axis 100, pushing the two rotating rings 320 towards their corresponding stationary rings 220, ensuring that the end faces of the rotating rings 320 and stationary rings 220 are always in tight contact, maintaining the sealing effect of the sealing pair.

[0040] During the operation of the rotary joint, even if the rotating ring 320 and the stationary ring 220 experience slight wear, the spring 330 can compensate for the wear through elastic elongation, ensuring that the rotating ring 320 and the stationary ring 220 remain in contact. This prevents the sealing gap from increasing and leakage from wear. The bidirectional pushing structure of the spring 330 ensures that the two sets of sealing surfaces are subjected to uniform force and have a stable fit, significantly improving sealing reliability and service life.

[0041] Based on this, a spring channel 213 is provided inside the housing 310. The spring channel 213 is located between the two moving rings 320 and is used to accommodate the spring 330. The spring channel 213 is independently set up with the accommodating cavity 321, the transition cavity 322 and the output flow channel 311.

[0042] A spring channel 213 is provided inside the housing 310. The spring channel 213 is located between the two moving rings 320 and extends axially along the central axis 100. The spring channel 213 accommodates the spring 330, maintaining its stable posture internally and preventing tilting, displacement, or jamming during extension and retraction. The spring channel 213 is independent of the receiving cavity 321, the transition cavity 322, and the output channel 311, and is not interconnected. This ensures that polishing fluid does not enter the interior of the spring channel 213, preventing abrasive particles in the polishing fluid from adhering to the spring 330 and affecting its elasticity. It also prevents impurities generated from spring wear from entering the polishing fluid channel and causing contamination. The independent spring channel 213 improves structural stability, ensuring the spring 330 always operates in a clean and stable environment, extending its service life.

[0043] Furthermore, the rotating ring 320 and / or the stationary ring 220 are made of silicon carbide. Silicon carbide possesses extremely high hardness, excellent wear resistance, good chemical stability, and a low coefficient of friction, making it ideal for applications in high-speed rotating sealing environments with abrasive erosion. Using silicon carbide for the rotating ring 320 and stationary ring 220 significantly reduces wear on the sealing pair during relative rotation, reduces wear particle generation, and improves the cleanliness of the polishing fluid from the source. Simultaneously, silicon carbide is less prone to chemical reaction with the polishing fluid and will not be corroded by it, further improving the service life of the sealing pair and the overall reliability of the rotary joint.

[0044] Furthermore, the rotary joint is provided with multiple sealing structures inside: a first seal is provided between the central shaft 100 and the stationary ring seat 210; a second seal is provided between the stationary ring seat 210 and the stationary ring 220; and a third seal is provided between the rotating ring 320 and the housing 310.

[0045] The first, second, and third seals are all annular (not shown) and are coaxially arranged with the central shaft 100, the rotating ring 320, the stationary ring 220, the stationary ring seat 210, and the housing 310. A first seal is provided between the central shaft 100 and the stationary ring seat 210, sealing the area between them to prevent polishing fluid from leaking outwards from the mating gap. A second seal is provided between the stationary ring seat 210 and the stationary ring 220, sealing the area between them to prevent polishing fluid from leaking outwards from the assembly gap between them. A third seal is provided between the rotating ring 320 and the housing 310, sealing the area between them to prevent polishing fluid from leaking outwards from the mating gap between them.

[0046] Through the cooperation of the first, second, and third seals, all assembly gaps inside the rotary joint, except for the sealing pair between the rotating ring 320 and the stationary ring 220, are reliably sealed, preventing polishing fluid leakage under normal operating conditions. Only a small, controllable amount of leakage may occur at the sealing pair between the rotating ring 320 and the stationary ring 220. This leakage is small and stable, and can be addressed through subsequent flushing to ensure the overall cleanliness of the rotary joint.

[0047] Furthermore, such as Figure 2 As shown, a gap space 313 is formed between the housing 310 and the moving ring 320, and the sealing pair is located in the gap space 313; the gap space 313 is connected to the spring channel 213; two stationary ring seats 210 are defined as the first stationary ring seat 211 and the second stationary ring seat 212, the first stationary ring seat 211 and / or the central shaft 100 are provided with a first water channel (not shown), and the second stationary ring seat 212 and / or the central shaft 100 are provided with a second water channel (not shown); the first water channel, the gap space 313, the spring channel 213, the gap space 313, and the second water channel are connected in sequence to form a flushing channel for removing the leaked polishing fluid.

[0048] A gap space 313 is formed between the housing 310 and the moving ring 320. The sealing pair is located in the gap space 313 so that the leaked polishing liquid can directly enter the gap space 313 for timely treatment. The gap space 313 is connected to the spring channel 213 to form a continuous flow area, providing a flow path for the rinsing water.

[0049] The two stationary ring seats 210 are defined as the first stationary ring seat 211 and the second stationary ring seat 212, respectively. The first stationary ring seat 211 and / or the central shaft 100 have a first water channel inside, and the second stationary ring seat 212 and / or the central shaft 100 have a second water channel inside. The first water channel, the gap space 313, the spring channel 213, the gap space 313, and the second water channel are sequentially connected to form a continuous and complete rinsing channel. The rinsing channel is independent of the polishing fluid channel and does not interfere with each other. Clean rinsing water is introduced into the rinsing channel. The rinsing water flows in from the first water channel, flows sequentially through the gap space 313, the spring channel 213, and the gap space 313 on the other side, and finally flows out from the second water channel. In one embodiment, the first water channel and the second water channel are formed on the first stationary ring seat and the second stationary ring seat, and the first water channel and the second water channel extend to the central axis 100; preferably, clearance holes can be formed on the first stationary ring seat 211 and the second stationary ring seat 212 to facilitate the flushing water to enter the gap space 313 from the first water channel or to flow out of the second water channel from the gap space 313.

[0050] like Figure 2As shown, during the flow process, the flushing water continuously envelops the sealing pair formed by the rotating ring 320 and the stationary ring 220, making the sealing pair completely immersed in the liquid environment. This significantly improves the lubrication conditions of the sealing pair, reduces the frictional resistance and wear of the rotating ring 320 and the stationary ring 220 during relative rotation, reduces particle generation, and improves the cleanliness of the rotary joint.

[0051] Meanwhile, any trace amounts of polishing fluid leaking from the sealing joint between the moving ring 320 and the stationary ring 220 will directly enter the flushing channel, where it will be quickly carried away by the continuously flowing flushing water. This prevents the leaked polishing fluid from crystallizing in the air and avoids the formation of hard crystal particles. The flushing channel design not only improves the lubrication effect of the sealing joint and extends its service life, but also completely solves the problems of silicon wafer scratches and excessive particle counts caused by polishing fluid leakage and crystallization. This allows the rotary joint to meet the stringent requirements of polishing large-size silicon wafers in advanced processes.

[0052] Furthermore, multiple spring channels 213 are provided, and these multiple spring channels 213 are distributed circumferentially along the central axis 100. The multiple spring channels 213 are evenly distributed circumferentially along the central axis 100; the multi-channel structure makes the springs 330 more evenly arranged, the preload on the moving ring 320 more balanced, and the sealing pair more stably fitted; at the same time, the multiple spring channels 213 can serve as part of the flushing flow channel, increasing the flushing water flow area and velocity, enhancing the flushing effect, further improving the ability to treat leaked polishing fluid, and ensuring that the rotary joint maintains a high level of cleanliness even under long-term continuous operation.

[0053] A rotary joint for a double-sided polishing machine includes a central shaft 100, a stationary component 200, and a rotating component 300. The stationary component 200 includes two stationary ring seats 210 and two stationary rings 220. The rotating component 300 includes a housing 310, two rotating rings 320, and corresponding elastic pre-tightening structures and flow channel structures. The rotary joint internally has independent polishing fluid flow channels and flushing flow channels. The polishing fluid flow channels are used to achieve stable delivery of the polishing fluid, while the flushing flow channels are used to flush away trace amounts of polishing fluid leaking from the sealing surfaces, preventing polishing fluid crystallization, improving lubrication conditions of the sealing surfaces, reducing wear, and improving the overall cleanliness of the rotary joint.

[0054] The dual-end sealing pair structure, coupled with the pre-tightening of the bidirectional spring 330, ensures that the dynamic ring 320 and the stationary ring 220 always maintain a stable fit, resulting in high sealing reliability. The dynamic ring 320 and the stationary ring 220 are made of high-hardness, high-wear-resistant materials, which significantly reduces the generation of wear particles. An independent flushing channel is set inside to keep the sealing pair in a liquid environment at all times, which improves the lubrication effect, reduces friction loss, and removes the leaked polishing fluid in time to avoid crystallization. This reduces the risk of particle contamination from the source and significantly improves the quality of silicon wafer processing.

[0055] This application also proposes a double-sided polishing machine with the aforementioned rotary joint. The rotary joint is installed at the polishing slurry supply position of the double-sided polishing machine, stably and cleanly delivering the polishing slurry between the polishing discs to achieve high-precision chemical mechanical polishing of large-size silicon wafers. By adopting the rotary joint of this application, the double-sided polishing machine exhibits reliable sealing, low wear, low particulate contamination, and no risk of polishing slurry crystallization during operation, significantly improving the surface quality and processing stability of silicon wafers, reducing equipment maintenance frequency, and increasing production efficiency and yield. It is suitable for advanced process processing of 12-inch and larger large-size silicon wafers.

[0056] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0057] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A rotary joint for a double-sided polishing machine, characterized in that, include: Central axis (100); A stationary component (200), the stationary component (200) comprising: There are two stationary ring seats (210), each of which is annularly sleeved on the central shaft (100) and fixedly connected to the central shaft (100); Two stationary rings (220) are provided, each stationary ring (220) is annularly sleeved on the central shaft (100), and the stationary ring (220) is fixedly connected to the stationary ring seat (210), and the two stationary rings (220) are arranged opposite to each other; and A rotating assembly (300) comprising: A housing (310) is sleeved on the central shaft (100) and located between the two stationary ring seats (210). The housing (310) is rotatably connected to the two stationary ring seats (210) so that the housing (310) can rotate relative to the central shaft (100). Two rotating rings (320) are provided, and the two rotating rings (320) are sleeved on the central shaft (100). The rotating rings (320) are fixedly connected to the housing (310) so that the rotating rings (320) can rotate with the housing (310). The rotating rings (320) and the stationary rings (220) are arranged in a one-to-one correspondence. The end face of the rotating ring (320) near the stationary ring (220) abuts against the end face of the stationary ring (220) near the rotating ring (320) so that two sets of sealing pairs are formed between the two sets of rotating rings (320) and the stationary rings (220). An annular cavity (321) is formed between the outer wall of the moving ring (320) and the central shaft (100); an input channel (110) is provided in the central shaft (100), and the input channel (110) is connected to the cavity (321); an output channel (311) is provided on the housing (310), and the output channel (311) is connected to the cavity (321).

2. The rotary joint of a double-sided polishing machine according to claim 1, characterized in that, An annular transition cavity (322) is formed between the two moving rings (320); the receiving cavity (321) and the output flow channel (311) are connected through the transition cavity (322).

3. The rotary joint of a double-sided polishing machine according to claim 2, characterized in that, The rotating assembly (300) also includes: A spring (330) is disposed between the two moving rings (320), and the two ends of the spring (330) respectively abut against the two moving rings (320) to apply a preload force toward the corresponding stationary ring to the two moving rings (320).

4. The rotary joint of a double-sided polishing machine according to claim 3, characterized in that, A spring channel (213) is provided inside the housing (310). The spring channel (213) is located between the two moving rings (320) and is used to accommodate the spring (330). The spring channel (213) is independently arranged with respect to the accommodating cavity (321), the transition cavity (322) and the output flow channel (311).

5. The rotary joint of a double-sided polishing machine according to claim 1, characterized in that, Bearings are provided between the housing (310) and the two stationary ring seats (210), and the housing (310) is rotatably supported relative to the stationary ring seats (210) by the bearings.

6. The rotary joint of a double-sided polishing machine according to claim 1, characterized in that, The moving ring (320) and / or the stationary ring (220) are made of silicon carbide material.

7. The rotary joint of a double-sided polishing machine according to claim 1, characterized in that, A first sealing element is provided between the central shaft (100) and the stationary ring seat (210); a second sealing element is provided between the stationary ring seat (210) and the stationary ring (220); and a third sealing element is provided between the moving ring (320) and the housing (310).

8. The rotary joint of a double-sided polishing machine according to claim 4, characterized in that, A gap space (313) is formed between the housing (310) and the moving ring (320), and the sealing pair is located in the gap space (313); the gap space (313) is connected to the spring channel (213); The two stationary ring seats (210) are defined as a first stationary ring seat (211) and a second stationary ring seat (212). The first stationary ring seat (211) and / or the central shaft (100) are provided with a first water channel, and the second stationary ring seat (212) and / or the central shaft (100) are provided with a second water channel. The first water channel, the gap space (313), the spring channel (213), the gap space (313), and the second water channel are connected in sequence to form a flushing channel for removing the leaked polishing fluid.

9. The rotary joint of a double-sided polishing machine according to claim 8, characterized in that, The spring channel (213) is provided in multiple ways, and the multiple spring channels (213) are distributed circumferentially along the central axis (100).

10. A double-sided polishing machine, characterized in that, It has a rotary joint as described in any one of claims 1-9.

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