Synchronous monocrystalline silicon wafer double-sided grinding device

Abstract

The invention discloses a synchronous monocrystalline silicon wafer double-sided grinding device. The device comprises a base, a grinding mechanism and a spraying mechanism, the grinding mechanism comprises a mounting disc fixed on the base, a lower grinding disc fixed in the mounting disc, an upper grinding disc rotationally mounted above the lower grinding disc and a plurality of wandering star wheels, and a placement groove is formed in the middle of each wandering star wheel; a driving gear driven by a motor is arranged on the base, and the driving gear is opposite to the upper grinding disc in rotating direction; a gear ring is fixed to the inner wall of the mounting disc, and the wandering star wheel is meshed with the driving gear and the gear ring at the same time. The device has the advantages that when the driving gear rotates, the wandering star wheel drives the monocrystalline silicon wafer to do planetary motion, meanwhile, under the action of the bevel gear set, the upper grinding disc rotates in the direction opposite to the driving gear, and at the moment, relative motion is formed between every two of the lower grinding disc, the monocrystalline silicon wafer and the upper grinding disc; the two faces of the monocrystalline silicon wafer can be ground by the lower grinding disc and the upper grinding disc in different directions, the grinding strength and uniformity are improved, and therefore the grinding effect and the machining efficiency are improved.

Description

Technical Field

[0001] This invention relates to a single-crystal silicon wafer processing equipment, specifically a synchronous single-crystal silicon wafer double-sided grinding device. Background Technology

[0002] Monocrystalline silicon wafers are thin sheets made of high-purity monocrystalline silicon material, possessing a highly ordered atomic arrangement structure, and are one of the fundamental materials in semiconductor, photovoltaic, and other fields. During the processing of monocrystalline silicon wafers, grinding ensures surface flatness, thus requiring a grinding device. For example, patent CN117260532A discloses an integrated monocrystalline silicon wafer grinding mechanism, including a frame, a double-sided clamping device, and an integrated grinding and polishing device. The double-sided clamping device includes a lower fixed base, an upper fixed base, a turntable, a dual-output shaft motor, a synchronous transmission rod, and a telescopic clamping rod. A coaxial and rotatable turntable is mounted on the lower and upper fixed bases. A dual-output shaft motor is mounted on the frame, and the turntable is rotated via synchronous transmission rods at both ends of the motor. The turntable is equipped with a telescopic clamping rod to hold the monocrystalline silicon wafer. The integrated grinding and polishing device is installed between the upper and lower fixed bases. Although the grinding mechanism can continuously clamp the single-crystal silicon wafer while avoiding the grinding and polishing device, in actual use, the processing effect is poor and the processing efficiency is low due to the inconvenience of reverse rotation. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a synchronous single-crystal silicon wafer double-sided grinding device that is convenient for reverse rotation and has high processing efficiency.

[0004] To solve the above-mentioned technical problems, the present invention provides a synchronous double-sided grinding device for monocrystalline silicon wafers, comprising a base, a grinding mechanism disposed on the base, and a spraying mechanism disposed beside the base; the grinding mechanism includes a mounting plate fixed on the base, a lower grinding plate fixed within the mounting plate, an upper grinding plate rotatably mounted above the lower grinding plate via a lifting mechanism, and a plurality of planetary wheels disposed between the lower grinding plate and the upper grinding plate, wherein each planetary wheel has a mounting groove in its center for placing the monocrystalline silicon wafer to be ground; a drive gear driven by a motor is rotatably disposed on the base, the drive gear rotating in the opposite direction to the upper grinding plate; a gear ring is fixed on the inner wall of the mounting plate, and the planetary wheels simultaneously mesh with the drive gear and the gear ring.

[0005] The lower grinding disc has a through groove in the middle, and the drive gear is disposed in the through groove; the motor is disposed inside the base, and its output axis passes through the wall of the base and is fixedly connected to the bottom of the drive gear.

[0006] The lifting mechanism includes a mounting frame fixed to the base and an electric push rod disposed on the top of the mounting frame; the telescopic rod portion of the electric push rod passes downward through the mounting frame and is fixedly connected to a movable seat, on which a water tank is rotatably mounted, and the upper grinding disc is fixed to the bottom of the water tank by multiple connecting rods.

[0007] A guide rod is provided between the mounting bracket and the movable seat.

[0008] The spraying mechanism includes a liquid storage tank located next to the base, a water pump located inside the liquid storage tank, and a corrugated pipe extending from the output end of the water pump. The corrugated pipe is used to guide the grinding liquid into the grinding mechanism.

[0009] An extension block is fixed on the movable seat and an infusion tube extending to the top of the water tank is embedded therein. The corrugated pipe is connected to the other end of the infusion tube. A spray pipe for the grinding liquid to flow down is provided between the water tank and the upper grinding disc. A drain hole is opened on the mounting plate.

[0010] The top of the spray pipe is equipped with a filter screen with a handle.

[0011] The drain hole is connected to the storage tank via a return pipe, and a filter mechanism is provided on the return pipe.

[0012] The filtration mechanism includes a filter box fixed to the side wall of the base, the filter box having an opening on the side and a removable filter box cover at the opening; a filter frame is placed inside the filter box, and multiple layers of filter screens are arranged inside the filter frame, the filter screens being arranged at an angle and the pore size of each layer decreasing from top to bottom.

[0013] The drive gear and the upper grinding disc are connected by a bevel gear set; the upper grinding disc has a gear groove at the bottom, and the bevel gear set includes a drive bevel gear fixed to the drive gear, a transmission bevel gear rotatably mounted on the side wall of the gear groove and capable of meshing with the drive bevel gear, and a driven bevel gear fixed to the top surface of the gear groove and meshing with the transmission bevel gear.

[0014] The advantages of this invention are: (1) When the drive gear rotates, the planetary wheel carries the single crystal silicon wafer to be ground in planetary motion. At the same time, under the action of the bevel gear set, the upper grinding disc rotates in the opposite direction to the drive gear. At this time, the lower grinding disc, the single crystal silicon wafer and the upper grinding disc form relative motion between each other. That is, the two sides of the single crystal silicon wafer can be ground by the lower grinding disc and the upper grinding disc in different directions. Compared with the traditional grinding device, this device is convenient to rotate in the opposite direction, and the grinding force and uniformity are improved. The grinding and polishing effect and processing efficiency are also greatly improved. (2) A guide rod is provided between the mounting frame and the movable seat, which enhances the stability of the movable seat when it moves, making the lifting process of the upper grinding disc and the meshing process of the transmission bevel gear and the active bevel gear smoother, which is more conducive to the development of the processing flow. (3) A return pipe for recycling grinding waste liquid for secondary use is set between the grinding mechanism and the spraying mechanism, which makes the grinding liquid utilization rate higher. A filter mechanism passes through the pipeline, in which multiple layers of filter screens are installed in an inclined posture in a detachable filter frame and the pore size of each layer decreases from top to bottom, making the filter screen easy to replace and the filtration effect better. The purity of the recycled grinding liquid is higher. The recycled grinding liquid enables the device to carry out continuous grinding for a long time, while saving costs. (4) A filter screen with a handle is installed at the top of the spray pipe. The filter screen can reduce the impact of impurities in the grinding liquid on the grinding effect, and the handle can make it easy for operators to replace the filter screen. Attached Figure Description

[0015] Figure 1 This is a perspective view of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a cross-sectional view of the grinding mechanism of the present invention; Figure 4 for Figure 2 Enlarged view of point A; Figure 5 for Figure 2 Enlarged view of point B; Figure 6 for Figure 2 Enlarged view of point C; Figure 7 This is a cross-sectional view of the filtration mechanism of the present invention. Detailed Implementation

[0016] The synchronous single-crystal silicon wafer double-sided polishing apparatus of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] As shown in the figure, the synchronous single-crystal silicon wafer double-sided polishing device of the present invention includes a hollow base 1, a polishing mechanism 2 on the base 1, and a mounting plate 2-5 fixed to the upper surface of the base 1. A lower polishing plate 2-1 is fixed on the inner bottom surface of the mounting plate 2-5. A circular through groove is opened in the center of the lower polishing plate 2-1, and a thrust ball bearing is placed in the through groove. A drive gear 6 is mounted on the thrust ball bearing. A motor 5 is fixed on the top surface of the inner cavity of the base 1. The output axis of the motor 5 passes through a through hole opened in the wall of the base 1 and is fixedly connected to the lower surface of the drive gear 6. A gear ring 2-6 is fixed on the inner wall of the mounting plate 2-5. Four planetary gears 2-3 are evenly arranged on the lower polishing plate 2-1. The planetary gears 2-3 mesh with the drive gear 6 and the gear ring 2-6 at the same time. A placement groove 2-4 for placing the single-crystal silicon wafer to be polished is opened in the center of the planetary gears 2-3, so that the single-crystal silicon wafer to be polished can be carried in planetary motion with the rotation of the drive gear 6.

[0018] A C-shaped mounting bracket 4-1 is fixed to the upper rear side of the base 1. An electric push rod 4-2 is fixed to the top surface of the mounting bracket 4-1. The telescopic rod portion of the electric push rod 4-2 passes downward through the mounting bracket 4-1 and is fixedly connected to the movable seat 4-3. Two guide rods 4-6 parallel to the telescopic rod are also provided between the mounting bracket 4-1 and the movable seat 4-3. The guide rods 4-6 are used to make the movable seat 4-3 more stable during lifting and lowering. The bottom end of the guide rod is fixed to the upper surface of the movable seat 4-3, and the top end passes through the through hole at the corresponding position on the mounting bracket 4-1 and extends upward as a movement margin. The mounting bracket 4-1, the electric push rod 4-2, the movable seat 4-3, and the guide rods 4-6 together constitute the lifting mechanism 4.

[0019] The movable base 4-3 has an internal cavity and a rotatable water tank 4-4 is installed at its lower part via a connector. The water tank 4-4 is used to temporarily hold the grinding fluid from the spraying mechanism 3. The spraying mechanism 3 includes a storage tank 3-1 located next to the base 1, a water pump 3-2 placed on the bottom surface of the storage tank 3-1, and a corrugated pipe 3-3 extending upward from the output end of the water pump 3-2 to the outside of the storage tank 3-1. An extension block 3-4 is fixed to the side wall of the movable base 4-3, and a delivery pipe 3-5 is embedded in it. One end of the delivery pipe 3-5 extends downward to the top of the water tank 4-4, and the other end is connected to the corrugated pipe 3-3, thus forming a pipeline for delivering the fluid from the storage tank 3-1 to the water tank 4-4.

[0020] The lower surface of the water tank 4-4 is fixedly connected to an upper grinding disc 2-2 corresponding to the lower grinding disc 2-1 by multiple connecting rods 4-5. The bottom of the upper grinding disc 2-2 has a gear groove 7-1 opening upwards. A driven bevel gear 7-4 is fixed on the top surface of the gear groove 7-1. A transmission bevel gear 7-3 that meshes with the driven bevel gear 7-4 is rotatably mounted on the side wall. An active bevel gear 7-2 that can mesh with the transmission bevel gear 7-3 is fixed on the upper surface of the drive gear 6. The active bevel gear 7-2, the transmission bevel gear 7-3, and the driven bevel gear 7-4 together constitute a bevel gear set 7. The bevel gear set 7 is used to make the drive gear 6 and the upper grinding disc 2-2 form a transmission relationship with opposite rotation directions.

[0021] The water tank 4-4 and the upper grinding disc 2-2 also have corresponding through holes, through which spray pipes 3-6 are connected. Spray pipes 3-6 are used to allow the polishing slurry to flow to the contact surfaces when the device polishes the single crystal silicon wafer, namely the gap between the upper grinding disc 2-2 and the planetary wheel 2-3, and between the planetary wheel 2-3 and the lower grinding disc 2-1. A filter screen 3-8 with a handle is also installed in the water tank 4-4 at the top of the spray pipe 3-6. The filter screen can reduce the impact of impurities in the polishing slurry on the polishing effect, and the handle makes it easy for the operator to replace the filter screen. The bottom surface of the mounting plate 2-5 has a drain hole 3-7 located between the lower grinding disc 2-1 and the gear ring 2-6. The drain hole 3-7 is connected to the storage tank 3-1 through a return pipe 3-9 for collecting polishing waste liquid for secondary use. There is a filter mechanism 8 on the pipeline to filter out polishing debris in the waste liquid to improve the purity of the recovered polishing slurry.

[0022] The filtration mechanism 8 includes a filter box 8-1 fixed to the side wall of the base 1. The filter box 8-1 has an opening on the side and a removable filter box cover 8-2 is provided at the opening. A filter frame 8-3 is placed inside the filter box 8-1. Multiple layers of filter screens 8-4 are provided inside the filter frame 8-3. The filter screens 8-4 are placed in an inclined position and the pore size of each layer decreases from top to bottom to obtain a better filtration effect.

[0023] In actual use, the electric push rod 4-2 first drives the movable seat 4-3 to move the upper grinding disc 2-2 upward, and adds the single crystal silicon wafer to be ground into the mounting slots 2-4 on each planetary wheel 2-3. Then, the electric push rod 4-2 is started again to lower the upper grinding disc 2-2, so that the transmission bevel gear 7-3 meshes with the driving bevel gear 7-2, and the grinding can be started. When the operator first starts the water pump 3-2 to add polishing fluid to the polishing mechanism 2, and then starts the motor 5, the drive gear 6 begins to rotate. The planetary wheel 2-3 then carries the monocrystalline silicon wafer to be polished in a planetary motion. That is, the planetary wheel 2-3 rotates on its own axis while rotating in the same direction as the drive gear 6. At the same time, the upper polishing disc 2-2 rotates in the opposite direction to the drive gear 6 under the action of the bevel gear set 7. At this time, the lower polishing disc 2-1, the monocrystalline silicon wafer and the upper polishing disc 2-2 form relative motion between each other. That is, the two sides of the monocrystalline silicon wafer can be polished by the lower polishing disc 2-1 and the upper polishing disc 2-2 in different directions. Compared with the traditional polishing process, this method improves the polishing force and uniformity, and the polishing effect and processing efficiency are greatly improved. After the grinding fluid flows through the grinding gap, it is filtered by the filter mechanism 8 through the return pipe 3-9 and then returned to the storage tank 3-1. It is then pumped by the water pump 3-2 through the corrugated pipe 3-3 and the delivery pipe 3-5 to the water pool 4-4. This cycle enables long-term continuous grinding and multiple uses of the grinding fluid, thereby saving costs.

[0024] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A synchronous single-crystal silicon wafer double-sided polishing device, characterized in that: The system includes a base (1), a grinding mechanism (2) mounted on the base (1), and a spraying mechanism (3) mounted on the side of the base (1). The grinding mechanism (2) includes a mounting plate (2-5) fixed on the base (1), a lower grinding plate (2-1) fixed inside the mounting plate (2-5), an upper grinding plate (2-2) rotatably mounted above the lower grinding plate (2-1) via a lifting mechanism (4), and a spraying mechanism (3) mounted on the lower grinding plate (2-1) and the upper grinding plate (2-5). 2) Multiple planetary gears (2-3) are arranged between the planetary gears (2-3), and the middle of the planetary gears (2-3) is provided with a mounting groove (2-4) for placing the single crystal silicon wafer to be ground; a drive gear (6) driven by a motor (5) is rotatably arranged on the base (1), and the drive gear (6) rotates in the opposite direction to the upper grinding disc (2-2); a gear ring (2-6) is fixed on the inner wall of the mounting disc (2-5), and the planetary gears (2-3) mesh with the drive gear (6) and the gear ring (2-6) at the same time.

2. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 1, characterized in that: The lower grinding disc (2-1) has a through groove in the middle, and the drive gear (6) is set in the through groove; the motor (5) is set inside the base (1), and its output axis passes through the wall of the base (1) and is fixedly connected to the bottom of the drive gear (6).

3. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 2, characterized in that: The lifting mechanism (4) includes a mounting frame (4-1) fixed on the base (1) and an electric push rod (4-2) set on the top of the mounting frame (4-1); the telescopic rod part of the electric push rod (4-2) passes downward through the mounting frame (4-1) and is fixedly connected to a movable seat (4-3); a water tank (4-4) is rotatably mounted on the movable seat (4-3); and the upper grinding disc (2-2) is fixed to the bottom of the water tank (4-4) by multiple connecting rods (4-5).

4. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 3, characterized in that: A guide rod (4-6) is provided between the mounting bracket (4-1) and the movable seat (4-3).

5. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 3, characterized in that: The spraying mechanism (3) includes a liquid storage tank (3-1) located next to the base (1), a water pump (3-2) located in the liquid storage tank (3-1), and a corrugated pipe (3-3) extending from the output end of the water pump (3-2). The corrugated pipe (3-3) is used to introduce the grinding liquid into the grinding mechanism (2).

6. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 5, characterized in that: An extension block (3-4) is fixed on the movable seat (4-3) and an infusion tube (3-5) is embedded therein, one end of which extends to the top of the water tank (4-4). The corrugated pipe (3-3) is connected to the other end of the infusion tube (3-5). A spray pipe (3-6) for the grinding liquid to flow down is provided between the water tank (4-4) and the upper grinding disc (2-2). A drain hole (3-7) is opened on the mounting plate (2-5).

7. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 6, characterized in that: The top of the spray pipe (3-6) is equipped with a filter screen (3-8) with a handle.

8. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 6, characterized in that: The drain hole (3-7) is connected to the storage tank (3-1) through the return pipe (3-9), and a filter mechanism (8) is provided on the return pipe (3-9).

9. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to claim 8, characterized in that: The filtration mechanism (8) includes a filter box (8-1) fixed to the side wall of the base (1), the filter box (8-1) has an opening on the side and a removable filter box cover (8-2) is provided at the opening; a filter frame (8-3) is placed inside the filter box (8-1), and multiple layers of filter screens (8-4) are provided inside the filter frame (8-3), the filter screens (8-4) are placed in an inclined posture and the pore size of each layer decreases from top to bottom.

10. The synchronous single-crystal silicon wafer double-sided polishing apparatus according to any one of claims 1-9, characterized in that: The drive gear (6) and the upper grinding disc (2-2) are connected by a bevel gear set (7). The upper grinding disc (2-2) has a gear groove (7-1) at its bottom. The bevel gear set (7) includes a drive bevel gear (7-2) fixed on the drive gear (6), a transmission bevel gear (7-3) rotatably mounted on the side wall of the gear groove (7-1) and capable of meshing with the drive bevel gear (7-2), and a driven bevel gear (7-4) fixed on the top surface of the gear groove (7-1) and meshing with the transmission bevel gear (7-3).

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