A mechanical polishing apparatus for gallium arsenide single crystals

Abstract

The application belongs to the technical field of semiconductor manufacturing, and specifically discloses a gallium arsenide single crystal mechanical polishing device, which comprises a polishing table and a single crystal body, the polishing table is connected with a grinding disc through a rotating mechanism arranged below the inner side, the grinding disc is externally sleeved with a liquid collecting mechanism, the upper surface of the polishing table is fixedly connected with a bracket, the bracket is externally provided with a telescopic cylinder, the telescopic end of the telescopic cylinder is connected with an upper connecting rod, the upper connecting rod is connected with a rectangular shell through an externally arranged pneumatic guide, the rectangular shell is slidingly installed below the outside of a guide pipe, the four outer circumferential surfaces of the rectangular shell are all provided with guide sliding mechanisms, and the outer circumferences of the guide sliding mechanisms are all provided with cutting dripping elements, the application realizes stable clamping of single crystal wafers with different sizes, uniformly supplies polishing liquid, has high utilization rate, effectively avoids polishing defects, is environmentally friendly and non-polluting, significantly improves polishing precision and operation safety, and is suitable for high-precision machining requirements in the field of semiconductor manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology, and specifically discloses a gallium arsenide single crystal mechanical polishing device. Background Technology

[0002] Gallium arsenide (GaAs), as a representative of second-generation semiconductor materials, plays an irreplaceable core role in high-speed, high-frequency devices (such as HEMTs and HBTs), lasers, solar cells, and optoelectronic integrated circuits due to its high electron mobility, direct bandgap, and excellent optoelectronic properties. The fabrication of such high-performance devices places almost stringent requirements on the surface quality of the substrate material—namely, gallium arsenide single-crystal wafers: an ultra-smooth, damage-free, low-roughness, and stoichiometrically stable surface is required. Mechanical polishing, especially chemical mechanical polishing (CMP), is a key process step in obtaining such high-quality surfaces.

[0003] However, in existing technological practices aimed at achieving this goal, the performance of polishing equipment, especially the tooling fixtures and polishing slurry supply system, has become a bottleneck restricting the improvement of polishing effect and efficiency. Specifically, there are two prominent problems: First, the adaptability and fixation reliability of the tooling fixtures are insufficient. Existing gallium arsenide single crystal polishing equipment mostly uses vacuum adsorption clamping mechanisms. Vacuum adsorption requires extremely high flatness on the back of the wafer, and for wafers of different sizes, especially those with slight variations in thickness, the adsorption force is uneven, easily causing slippage or local "detachment" under polishing pressure, leading to uneven polishing or even fragmentation. Lateral clamping mechanisms are often designed for specific sizes, lacking versatility; changing wafer sizes requires changing the fixture, increasing preparation time and cost. More importantly, gallium arsenide single crystals are circular, and traditional fixtures struggle to achieve rapid clamping while ensuring circumferential and radial rigidity during high-speed rotation polishing. Even small displacements can cause sudden changes in local pressure in the polishing area, producing "oscillation marks" or "comet tail"-like micro-defects, severely affecting surface consistency and yield. Secondly, the supply method of polishing slurry (cutting fluid) is crude, with low utilization efficiency and a high risk of polishing defects. Current equipment commonly uses single-point or lateral dripping or spraying methods to supply polishing slurry. This method has significant drawbacks: First, the polishing slurry cannot accurately and evenly cover the entire dynamic polishing contact area, leading to a mismatch between chemical and mechanical effects within the polishing area, resulting in large differences in local material removal rate (MRR) and easily forming alternating light and dark "patterns" or "zebra stripes" on the wafer surface; Second, a large amount of polishing slurry is directly thrown out of the working area under centrifugal force, failing to effectively participate in the polishing reaction, causing serious waste of chemical reagents, especially for CMP slurries containing expensive nano-abrasives and precise chemical formulations, resulting in high costs; Third, the splashed waste liquid mixes with arsenic particles and abrasive fragments generated during the polishing process, forming aerosols that not only pollute the equipment interior and cleanroom environment but also pose a potential threat to the health of operators, increasing the difficulty and cost of waste disposal.

[0004] In summary, existing gallium arsenide single crystal mechanical polishing equipment has significant shortcomings in terms of rapid, stable, and universal wafer clamping, as well as efficient, directional, and environmentally friendly supply and recycling of polishing slurry. These problems directly affect the uniformity and repeatability of polished surface quality, increase production costs, and pose challenges to the safety of the production environment. Therefore, designing a novel polishing device that can achieve rapid and reliable clamping, optimize the polishing slurry flow field distribution, and integrate waste liquid collection is of urgent practical significance for improving the gallium arsenide single crystal polishing process and ensuring the performance and reliability of high-end semiconductor devices. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the background art, and to propose a gallium arsenide single crystal mechanical polishing device, including a polishing table and a single crystal. The polishing table is connected to a grinding disc via a rotating mechanism located on its inner lower side. A liquid collection mechanism is fitted around the grinding disc. A frame is fixedly connected to the upper surface of the polishing table. A telescopic cylinder is located outside the frame. An upper connecting rod is connected to the telescopic end of the telescopic cylinder. The upper connecting rod is connected to a rectangular shell via an externally located pneumatic guide. The rectangular shell is slidably installed on the lower outer side of a guide tube. Guide sliding mechanisms are provided on all four outer peripheral surfaces of the rectangular shell. A cutting dripping component is provided on the outside of multiple guide sliding mechanisms. A chuck is fixedly installed at the bottom end of the guide tube. Multiple guide sliding mechanisms clamp the single crystal in the middle of the chuck. Multiple grooves adapted to the guide sliding mechanisms are opened inside the chuck. A dust removal mechanism is provided on one side of the polishing table.

[0006] In the above technical solution, the rotating mechanism further includes a housing fixedly installed on the inner top wall of the polishing table, a motor fixedly installed on the outside of the housing, the output end of the motor being connected to the bottom of the grinding disc, and a controller being installed inside the polishing table.

[0007] In the above technical solution, the liquid collection mechanism further includes a cover plate fixedly sleeved on the outside of the grinding disc, and a drain pipe is connected to the bottom of the cover plate.

[0008] In the above technical solution, the pneumatic guide includes a cylinder, which is fixedly mounted on the upper surface of the chuck. A connecting rod is fixedly installed at the telescopic end of the cylinder. A sliding plate is fixedly installed at the end of the connecting rod away from the cylinder. Guide rods are installed at equal intervals along the circumferential direction at the bottom of the sliding plate. The bottom ends of multiple guide rods are fixed to the upper surface of the rectangular shell. The sliding plate and multiple guide rods are slidably inserted into the inside of the guide tube.

[0009] In the above technical solution, further, the multiple guide sliding mechanisms include connecting arms, one end of the connecting arm is rotatably engaged with the outer peripheral surface of the rectangular shell, and the other end is rotatably connected to a slide rod. The slide rod slides inside the slide groove inside the chuck, and arc-shaped limiting seats are provided on both sides of the slide rod and at the end near the connecting arm.

[0010] In the above technical solution, further, each of the sliding rods has a locking post inserted inside, and a buckle is fixedly installed at the bottom of the locking post. The cutting and dripping component is disposed inside multiple buckles, and a wear-resistant pad is provided on the outer surface of one side of the buckle. The wear-resistant pad abuts against the outer peripheral surface of the single crystal.

[0011] In the above technical solution, the cutting dripping component further includes a plastic tube, which is clamped inside multiple clips. The bottom of the plastic tube has drainage holes at equal intervals along the circumference. The plastic tube is connected to an injection tube through a connecting tube installed at the top inside. A metering valve is provided on the outside of the injection tube. A pump body is connected to the end of the injection tube away from the connecting tube. The pump body is fixedly installed on the upper surface of one side of the polishing table. A delivery tube is connected to the end of the pump body away from the injection tube.

[0012] In the above technical solution, the dust removal mechanism further includes a fan installed on one side of the polishing table. One end of the fan is connected to a ventilation pipe, and the end of the ventilation pipe away from the fan is connected to an air inlet box. A bottom shell is fixedly installed on the upper surface of the polishing table away from the pump body. The air inlet box is slidably installed inside the bottom shell. The bottom shell and the air inlet box are connected by bolts that pass through each other. Both ends of the bolts are threaded with nuts. The two sets of nuts abut against the outer walls of the bottom shell on both sides. A suction hood is connected to the end of the air inlet box away from the ventilation pipe. The suction hood is located above the outside of the grinding disc and the cover plate. A circular groove adapted to the up and down movement of the chuck is opened inside the suction hood. The diameter of the circular groove is larger than that of the chuck.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The designed four-way clamping structure effectively solves the problems of adaptability, stability, and versatility in gallium arsenide (GaAs) single-wafer clamping. Specifically, the guide sliding mechanism, consisting of connecting arms, sliding rods, and arc-shaped limiting holders, drives multiple sliding rods to move synchronously inward or outward along the radial grooves inside the chuck when the rectangular shell is raised and lowered in a controlled manner. This linkage mechanism allows multiple arc-shaped limiting holders to uniformly and flexibly abut against the outer edge of single-wafers of different diameters from the circumferential direction, achieving rapid centering and rigid locking. Compared with traditional vacuum adsorption, this mechanical clamping method has no stringent requirements for the flatness of the wafer back side, and the clamping force is stable and reliable, avoiding the risk of slippage and "detachment" during the polishing process. It ensures the uniform transmission of polishing pressure, thereby suppressing the generation of micro-defects such as "oscillation marks" or "comet tails" from the root, and significantly improving the consistency of the polished surface and the processing yield.

[0014] 2. This invention directly clamps a ring-shaped plastic tube into multiple radially distributed clips, integrating the cutting fluid dripping component with the wafer clamping structure in a physical structure. This unique design "weaves" the polishing fluid supply path into the clamping frame, with the plastic tube moving radially synchronously with the clips. The direct effect is that the circumferential position of the polishing fluid seepage always maintains a fixed relative relationship with the wafer clamping edge. Regardless of the wafer size being clamped, the seepage hole can be aligned with the polishing area on the inner side of the wafer's outer edge, ensuring consistency between the fluid supply position and the polishing contact area from the source. This effectively avoids the problem of inconsistent relative positions between the nozzle and the rotating wafer in traditional lateral dripping methods, where the fluid flow is easily affected by centrifugal force. This allows the polishing fluid seeping from the seepage hole to reach the wafer edge directly with the shortest distance and lowest initial velocity during polishing, and is then "carried" into the polishing interface by the rotating wafer surface, forming a uniform and continuous liquid film. This greatly reduces the splashing loss of polishing slurry in the air and the ineffective runoff on the grinding wheel, significantly improves the utilization efficiency of polishing slurry, and fundamentally eliminates polishing "patterns" caused by uneven slurry supply.

[0015] 3. Through the coordinated design of the liquid collection and dust removal mechanisms, efficient collection and environmentally friendly treatment of waste liquid and dust generated during the polishing process are achieved. A cover plate fixed to the outside of the polishing disc effectively catches splashed waste liquid and discharges it centrally through a drain pipe at the bottom, preventing waste liquid from contaminating the equipment and working environment. The independently set dust removal mechanism uses a fan to generate negative pressure, directly extracting aerosols (mixed with arsenic particles, abrasive debris, and a small amount of droplets) generated during the polishing process above the polishing area via a suction hood. Circular grooves inside the suction hood ensure that the chuck and the wafer it holds are not interfered with during vertical polishing operations. This combined collection solution greatly reduces the dispersion of harmful dust and waste liquid, protects the health and safety of operators, reduces pollution to the cleanroom environment, and simplifies subsequent waste disposal procedures. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is another schematic diagram of the overall connection structure of the present invention; Figure 3 This is a schematic diagram of the connection structure between the grinding disc and the rotating mechanism of the present invention; Figure 4 This is a schematic diagram of the connection structure between the pneumatic guide and the duct of the present invention; Figure 5 This is a schematic diagram showing the disassembled structure of the inner side of the chuck of the present invention; Figure 6 This is a schematic diagram showing the partial structural connection between the conduit, the slide, and the guide rod of the present invention; Figure 7 This is a schematic diagram of a portion of the structure between the dust removal mechanism and the bottom shell of the present invention; Figure 8 This is a schematic diagram of the connection structure between the plastic tube and the buckle of the present invention; Figure 9 This is a schematic diagram of the connection structure of the rectangular shell sliding outside the conduit according to the present invention.

[0017] In the diagram: 1. Polishing table; 2. Fan; 3. Controller; 4. Pump body; 5. Cover plate; 6. Suction hood; 7. Connecting rod; 8. Frame; 9. Sliding plate; 10. Air inlet box; 11. Telescopic cylinder; 12. Ventilation pipe; 13. Grinding disc; 14. Housing; 15. Motor; 16. Drain pipe; 17. Cylinder; 18. Metering valve; 19. Guide rod; 20. Sliding rod; 21. Guide tube; 22. Chuck; 23. Connecting pipe; 24. Injection pipe; 25. Single crystal; 26. Buckle; 27. Plastic tube; 28. Connecting arm; 29. ​​Nut; 30. Upper connecting rod; 31. Drain hole; 32. Circular groove; 33. Bottom shell; 34. Bolt; 35. Delivery pipe; 36. Rectangular shell; 37. Limiting seat; 38. Locking post. Detailed Implementation

[0018] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the invention is not limited to the specific embodiments disclosed below.

[0020] like Figures 1-9The gallium arsenide single crystal mechanical polishing equipment shown includes a polishing table 1 and a single crystal 25. The polishing table 1 is connected to a grinding disc 13 via a rotating mechanism located on its inner lower side. A liquid collection mechanism is fitted around the grinding disc 13. A support 8 is fixedly connected to the upper surface of the polishing table 1. A telescopic cylinder 11 is located outside the support 8. An upper connecting rod 30 is connected to the telescopic end of the telescopic cylinder 11. The upper connecting rod 30 is connected to a rectangular shell 36 via an externally provided pneumatic guide. The rectangular shell 36 is slidably installed on the lower outside of the guide tube 21. Guide sliding mechanisms are provided on all four outer peripheral surfaces of the rectangular shell 36. A cutting dripping component is provided on the outside of multiple guide sliding mechanisms. A chuck 22 is fixedly installed at the bottom of the guide tube 21. Multiple guide sliding mechanisms clamp the single crystal 25 in the middle of the inside of the chuck 22. Multiple grooves adapted to the guide sliding mechanisms are opened inside the chuck 22. A dust removal mechanism is provided on one side of the polishing table 1. In this embodiment, before the equipment is started, the single crystal 25 to be polished is placed in the lower middle position inside the chuck 22; the pneumatic guide is activated by the controller 3 to drive the rectangular shell 36 to move axially along the guide tube 21. The rectangular shell 36 drives the four guide sliding mechanisms to synchronously retract towards the center along the sliding groove of the chuck 22 to achieve the centered clamping of the single crystal 25; the rotating mechanism is activated to drive the grinding disc 13 to rotate, and the telescopic cylinder 11 drives the upper connecting rod 30, the guide tube 21 and the chuck 22 to move down, so that the lower surface of the single crystal 25 contacts the polishing pad of the rotating grinding disc 13, and a preset polishing pressure is applied for mechanical polishing; during the polishing process, the cutting dripping part continuously supplies polishing liquid to the surface of the single crystal 25, the liquid collection mechanism collects waste liquid, and the dust removal mechanism simultaneously extracts the dust generated during polishing, completing the entire polishing operation; Specifically, this system integrates the clamping, stable polishing, liquid supply, and dust collection of gallium arsenide (GaAs) single crystal wafers, solving the problems of unstable clamping, uneven polishing, and severe pollution associated with traditional equipment. Through the linkage of a guide mechanism and pneumatic guides, it achieves adaptive clamping of single crystals of different sizes; the surrounding liquid supply from the cutting dripper ensures uniform coverage of the polishing surface; and the dust collection mechanism collects dust in real time, ensuring a safe working environment.

[0021] The rotating mechanism includes a housing 14 fixedly installed on the inner top wall of the polishing table 1, a motor 15 fixedly installed on the outside of the housing 14, the output end of the motor 15 being connected to the bottom of the grinding disc 13, and a controller 3 being installed inside the polishing table 1. In this embodiment, the controller 3 is a programmable PLC controller 3, which can drive the motor 15 to operate, so that its output shaft drives the grinding disc 13 to rotate, and cooperate to perform polishing operations.

[0022] The liquid collection mechanism includes a cover plate 5 fixedly sleeved on the outside of the grinding disc 13, and a drain pipe 16 is connected to the bottom of the cover plate 5; In this embodiment, during polishing, the grinding disc 13 rotates and the polishing liquid splashes in all directions. The annular groove structure of the cover plate 5 blocks the splashed waste liquid, allowing it to flow along the inner wall of the cover plate 5 to the bottom. Since the bottom of the cover plate 5 is fitted above the grinding disc 13, the waste liquid will gather inside the cover plate 5 and finally flow out naturally through the drain pipe 16 and be introduced into the external waste liquid treatment equipment. This method efficiently collects polishing slurry and reaction waste liquid splashed during the polishing process, preventing waste liquid from contaminating internal equipment components and the working environment; reducing polishing slurry waste and lowering production costs; and preventing waste liquid from mixing with dust to form aerosols, thereby improving the safety of the working environment.

[0023] The pneumatic guide includes a cylinder 17, which is fixedly mounted on the upper surface of the chuck 22. A connecting rod 7 is fixedly installed at the telescopic end of the cylinder 17. A slide plate 9 is fixedly installed at the end of the connecting rod 7 away from the cylinder 17. Guide rods 19 are installed at equal intervals along the circumference at the bottom of the slide plate 9. The bottom ends of multiple guide rods 19 are fixed to the upper surface of the rectangular shell 36. The slide plate 9 and multiple guide rods 19 are slidably inserted into the inside of the guide tube 21. In this embodiment, when clamping the single crystal, the controller 3 controls the cylinder 17, and the telescopic end extends to push the connecting rod 7 downward. The connecting rod 7 drives the slide 9 to slide downward along the inside of the guide tube 21. The slide 9 simultaneously drives the four guide rods 19 to move downward. The guide rods 19 drive the rectangular shell 36 to move downward along the axial direction of the guide tube 21. The rectangular shell 36 drives the guide sliding mechanism to retract towards the center, completing the clamping. When releasing the single crystal 25, the telescopic end of the cylinder 17 retracts, driving the slide 9, guide rods 19 and rectangular shell 36 to move upward. The guide sliding mechanism opens outward, and the polished single crystal 25 can be taken out.

[0024] Multiple guide mechanisms include a connecting arm 28, one end of which is rotatably engaged with the outer peripheral surface of the rectangular shell 36, and the other end is rotatably connected to a slide rod 20. The slide rod 20 slides inside the slide groove inside the chuck 22. Arc-shaped limiting seats 37 are provided on both sides of the slide rod 20 and at the end closest to the connecting arm 28. In this embodiment, when the rectangular shell 36 moves downward along the guide tube 21, the connecting arm 28 rotates around the hinge point under the drive of the rectangular shell 36, converting the axial movement into the radial movement of the slide rod 20, pushing the slide rod 20 to slide towards the center along the groove of the chuck 22; the four sets of guide sliding mechanisms act synchronously, the arc-shaped surface of the limiting card seat 37 is in contact with the outer peripheral surface of the single crystal 25, and the wear-resistant rubber pad increases the friction to prevent the single crystal 25 from sliding during polishing; since the limiting card seat 37 is arc-shaped on the side close to the single crystal 25 and the four sets of mechanisms are symmetrically distributed, the position of the single crystal can be automatically corrected to achieve centered clamping; when the rectangular shell 36 moves upward, the connecting arm 28 rotates in the opposite direction, driving the slide rod 20 to slide outward and release the single crystal, thereby achieving adaptive centered clamping of single crystals 25 of different sizes, and the pressure is buffered by the wear-resistant rubber pad to avoid rigid clamping, which could cause the single crystal 25 to crack when it contacts the grinding disc 13.

[0025] Each slide bar 20 has a locking post 38 inserted inside. The bottom of the locking post 38 is fixedly installed with a buckle 26. The cutting dripping component is set inside multiple buckles 26. A wear-resistant pad is provided on one side of the outer surface of the buckle 26. The wear-resistant pad abuts against the outer peripheral surface of the single crystal 25. The cutting dripping component includes a plastic tube 27, which is clamped inside multiple buckles 26. The bottom of the plastic tube 27 has drainage holes 31 at equal intervals along the circumferential direction. The plastic tube 27 is connected to an injection tube 24 through a connecting tube 23 installed inside and above. A metering valve 18 is provided outside the injection tube 24. A pump body 4 is connected to the end of the injection tube 24 away from the connecting tube 23. The pump body 4 is fixedly installed on one side of the upper surface of the polishing table 1. A receiving tube 35 is connected to the end of the pump body 4 away from the injection tube 24. In this embodiment, when the slide bar 20 slides towards the center, it drives the locking pin 38 and the buckle 26 to move synchronously. The wear-resistant pad on the inner side of the buckle 26 is tightly attached to the outer peripheral surface of the single crystal 25, fixing the single crystal wafer through friction. Since the buckle 26 is U-shaped and the wear-resistant pad has a certain elasticity, it can adapt to the slight irregularities on the outer peripheral surface of the single crystal wafer, ensuring tight clamping. The cutting dripping component is installed inside the four buckles 26 and moves synchronously with the buckles 26, always surrounding the single crystal 25 to ensure accurate liquid supply position. During polishing operation, the pump body 4 is started to pump the polishing liquid in the external storage tank into the receiving pipe 35. The liquid injection tube 24; the liquid supply flow rate is adjusted by the metering valve 18, and the polishing liquid flows into the annular plastic tube 27 through the connecting tube 23; since the bottom of the plastic tube 27 has uniformly distributed seepage holes 31, the polishing liquid slowly seeps out from the seepage holes 31 and drips onto the upper surface of the single crystal 25; as the grinding disc 13 rotates, the polishing liquid is evenly diffused to the entire polishing surface under the action of centrifugal force, providing lubrication, cooling and chemical action for mechanical polishing; the plastic tube 27 is clamped inside the buckle 26 and moves synchronously with the buckle 26, always maintaining the relative position of the seepage holes 31 and the single crystal 25, ensuring accurate liquid supply.

[0026] The dust removal mechanism includes a fan 2 installed on one side of the polishing table 1. One end of the fan 2 is connected to a ventilation pipe 12, and the end of the ventilation pipe 12 away from the fan 2 is connected to an air inlet box 10. A bottom shell 33 is fixedly installed on the upper surface of the end of the polishing table 1 away from the pump body 4. The air inlet box 10 is slidably installed inside the bottom shell 33. The bottom shell 33 and the air inlet box 10 are connected by a bolt 34 that passes through each other. Both ends of the bolt 34 are threaded with nuts 29. The two sets of nuts 29 abut against the outer walls on both sides of the bottom shell 33. The end of the air inlet box 10 away from the ventilation pipe 12 is connected to a suction hood 6. The suction hood 6 is located above the outside of the grinding disc 13 and the cover plate 5. The suction hood 6 has a circular groove 32 inside that is adapted to the chuck 22 to move up and down. The diameter of the circular groove 32 is larger than that of the chuck 22. In this embodiment, when the polishing operation is started, the fan 2 is started simultaneously. The fan 2 generates negative pressure, which is transmitted to the suction hood 6 through the ventilation pipe 12 and the air inlet box 10. The suction hood 6 is located above the polishing area, forming a negative pressure adsorption zone, which sucks in the dust, aerosols and other particles generated during polishing. The dust enters the fan 2 through the suction hood 6, the air inlet box 10 and the ventilation pipe 12, and is then introduced into external dust removal equipment such as a bag filter for filtration through the air outlet of the fan 2. When the chuck 22 is raised or lowered, the circular groove 32 inside the suction hood 6 provides the chuck 22 with room to move and avoids interference. By loosening the nut 29, the air inlet box 10 can slide along the bottom shell 33. When maintaining the grinding disc 13 later, the air inlet box 10 can be removed from the bottom shell 33.

[0027] In summary, this invention achieves rapid adaptive clamping of wafers through the linkage of the guide sliding mechanism and the pneumatic guide, achieves uniform supply of polishing fluid through the surrounding liquid seepage system, and achieves effective collection of waste through the coordinated operation of the liquid collection hood and the dust removal hood. Thus, it solves the problems of unstable clamping, uneven polishing, liquid waste and environmental pollution in an integrated manner.

[0028] Working principle: The operator initially places the single crystal 25 to be polished in the central area below the chuck 22. The controller 3 controls the cylinder 17 to start, and its telescopic end pushes the slide 9 downward along the guide tube 21 through the connecting rod 7. The multiple guide rods 19 fixedly connected to the slide 9 move down synchronously, thereby pushing the rectangular shell 36 downward along the guide tube 21. The downward movement of the rectangular shell 36 is converted into radial movement through the connecting arms 28 hinged on its four sides. The other end of each connecting arm 28 is rotatably connected to a slide rod 20, which is confined in a radial groove opened inside the chuck 22. Therefore, when the rectangular shell 36 moves down, the four sets of connecting arms 28 push the four slide rods 20 to slide radially towards the center synchronously along the groove of the chuck 22. Each slide rod 20 is connected to a buckle 26 through a buckle post 38, and the buckle 26 has a wear-resistant pad on its inner side. As the slide bar 20 slides inward, the four latches 26 approach and flexibly press against the outer circumferential surface of the single crystal 25 from the circumferential direction. Through the constraint of the arc-shaped limiting seat 37, the single crystal 25 achieves rapid, self-adaptive centering and stable clamping, suitable for wafers within a certain size range. When the latches 26 move, the internal plastic tube 27 adaptively deforms. After clamping, the telescopic cylinder 11 is driven to move downward, driving the guide tube 21, chuck 22, and single crystal 25 through the circular groove 32 to the upper surface of the grinding disc 13. The output of the motor 15 drives the grinding disc 13 to rotate, serving as the main motion for polishing. The telescopic cylinder 11 further applies controllable downward pressure, causing the lower surface of the single crystal 25, fixed by the chuck 22 and clamping mechanism, to contact the upper surface of the rotating grinding disc 13, initiating the mechanical polishing process. Simultaneously with polishing, the cutting fluid supply is activated. The pump 4 operates, pumping cutting fluid from an external source through the delivery pipe 35. The polishing slurry flows through the injection tube 24 and is precisely flow-controlled by the metering valve 18. Then, the slurry is introduced into an annular plastic tube 27 through the connecting tube 23. The slurry slowly and continuously seeps out and drips from multiple evenly spaced perforations 31 at the bottom of the plastic tube 27. Because the perforations 31 are arranged around the wafer, the polishing slurry can evenly cover the entire lower surface polishing contact area of ​​the single crystal 25, ensuring the uniformity of chemical action and mechanical removal and avoiding the formation of polishing patterns. During the polishing process, used cutting fluid, reaction byproducts, and grinding debris splash under centrifugal force and are blocked and collected by the cover plate 5 fixedly fitted outside the grinding disc 13. Waste liquid accumulating at the bottom of the cover plate 5 is discharged through the drain pipe 16 for centralized treatment. To prevent the spread of fine particles generated during polishing, a dust removal mechanism operates simultaneously. The fan 2 starts, generating negative pressure airflow at the suction hood 6. The suction hood 6 is connected to the fan 2 via the air inlet box 10 and ventilation pipe 12. Its position is designed above the grinding disc 13 and the cover plate 5, and it is fixed to the base shell 33 by bolts 34 and nuts 29. Dust and mist generated in the polishing area are captured by the suction hood 6 and discharged to the outside through an external hose, effectively purifying the working environment.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A gallium arsenide single crystal mechanical polishing apparatus, comprising a polishing table (1) and a single crystal (25), characterized in that: The polishing table (1) is connected to a grinding disc (13) via a rotating mechanism located on its inner side. A liquid collection mechanism is fitted around the grinding disc (13). A frame (8) is fixedly connected to the upper surface of the polishing table (1). A telescopic cylinder (11) is located on the outside of the frame (8). An upper connecting rod (30) is connected to the telescopic end of the telescopic cylinder (11). A rectangular shell (36) is connected to the upper connecting rod (30) via an externally provided pneumatic guide. The rectangular shell (36) is slidably installed on the lower outside of the conduit (21). A guide sliding mechanism is provided on all four outer circumferences of the rectangular shell (36). A cutting dripping component is provided on the outside of multiple guide sliding mechanisms. A chuck (22) is fixedly installed at the bottom of the conduit (21). Multiple guide sliding mechanisms clamp the single crystal (25) in the middle of the inside of the chuck (22). Multiple grooves adapted to the guide sliding mechanisms are opened inside the chuck (22). A dust removal mechanism is provided on one side of the polishing table (1). The rotating mechanism includes a housing (14) fixedly installed on the inner top wall of the polishing table (1), a motor (15) fixedly installed on the outside of the housing (14), the output end of the motor (15) being connected to the bottom of the grinding disc (13), and a controller (3) being installed inside the polishing table (1). The liquid collection mechanism includes a cover plate (5) fixedly sleeved on the outside of the grinding disc (13), and a drain pipe (16) is connected to the bottom of the cover plate (5). The pneumatic guide includes a cylinder (17), which is fixedly mounted on the upper surface of the chuck (22). A connecting rod (7) is fixedly installed at the telescopic end of the cylinder (17). A slide plate (9) is fixedly installed at the end of the connecting rod (7) away from the cylinder (17). Guide rods (19) are installed at equal intervals along the circumferential direction at the bottom of the slide plate (9). The bottom ends of multiple guide rods (19) are fixed on the upper surface of the rectangular shell (36). The slide plate (9) and multiple guide rods (19) are slidably inserted into the inside of the guide tube (21). The multiple guide sliding mechanisms include a connecting arm (28), one end of which is rotatably engaged with the outer peripheral surface of the rectangular shell (36), and the other end is rotatably connected to a slide rod (20). The slide rod (20) slides inside the slide groove inside the chuck (22). Arc-shaped limiting seats (37) are provided on both sides of the slide rod (20) and at the end closest to the connecting arm (28).

2. The gallium arsenide single crystal mechanical polishing equipment according to claim 1, characterized in that: Each slide bar (20) has a locking post (38) inserted inside. The bottom end of the locking post (38) is fixedly installed with a buckle (26). The cutting and dripping part is set inside multiple buckles (26). A wear-resistant pad is provided on one side of the outer surface of the buckle (26). The wear-resistant pad abuts against the outer peripheral surface of the single crystal (25).

3. The gallium arsenide single crystal mechanical polishing equipment according to claim 2, characterized in that: The cutting dripping component includes a plastic tube (27), which is fitted inside multiple clips (26). The bottom of the plastic tube (27) has drainage holes (31) at equal intervals along the circumferential direction. The plastic tube (27) is connected to an injection tube (24) through a connecting tube (23) installed on the upper part of the inside. A metering valve (18) is provided on the outside of the injection tube (24). A pump body (4) is connected to the end of the injection tube (24) away from the connecting tube (23). The pump body (4) is fixedly installed on the upper surface of one side of the polishing table (1). A receiving pipe (35) is connected to the end of the pump body (4) away from the injection tube (24).

4. The gallium arsenide single crystal mechanical polishing equipment according to claim 1, characterized in that: The dust removal mechanism includes a fan (2) installed on one side of the polishing table (1). One end of the fan (2) is connected to a ventilation pipe (12), and the end of the ventilation pipe (12) away from the fan (2) is connected to an air inlet box (10). A bottom shell (33) is fixedly installed on the upper surface of the polishing table (1) away from the pump body (4). The air inlet box (10) is slidably installed inside the bottom shell (33). The bottom shell (33) and the air inlet box (10) are connected by a common bolt (34). Connected, both ends of the bolt (34) are threaded with nuts (29), and the two sets of nuts (29) abut against the outer walls on both sides of the bottom shell (33). The end of the air inlet box (10) away from the ventilation pipe (12) is connected to the suction hood (6). The suction hood (6) is located above the outside of the grinding disc (13) and the cover plate (5). The suction hood (6) has a circular groove (32) inside that is adapted to the chuck (22) to move up and down. The diameter of the circular groove (32) is larger than that of the chuck (22).

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