Magnetic polishing fixture and polishing device

Abstract

The present invention belongs to the field of polishing technology, and specifically relates to a magnetic polishing fixture and a polishing device. In order to solve the problem that the processes of loading and removing the slices in the traditional polishing process are cumbersome, time-consuming and easy to break, the magnetic polishing fixture proposed by the present invention includes a fixture body, the front of the fixture body is provided with a first stopper, and the first stopper surface is used to place the workpiece to be polished; the back of the fixture body is provided with a plurality of blind holes, and the blind holes are used to place magnets; after the workpiece to be polished is placed on the first stopper surface, the magnets placed in the blind holes can adsorb the workpiece to be polished on the first stopper surface. The magnetic polishing fixture of the present invention uses magnetic force to adsorb the slices for loading and removing, and does not require the use of adhesives or oven heating, and can complete the processes of loading and removing the slices at room temperature. Not only does it take less time in the process of removing and loading the slices, but it also solves the problem that the traditional polishing machine uses adhesives for loading and removing the slices and is easy to break.

Description

Technical Field

[0001] The invention belongs to the technical field of polishing, and in particular relates to a magnetic polishing fixture and a polishing device. Background Art

[0002] In the semiconductor industry, single-crystal silicon rods are mechanically rolled into cylindrical rods, which are then cut into discs of a certain thickness. The edges of these discs are chamfered and then roughly ground with a grinder to form single-crystal silicon discs of a certain thickness and with a relatively flat surface. To make integrated circuit chips using single-crystal silicon wafers, oxidation, photolithography, corrosion, diffusion, ion implantation and other post-processing are required. These processes require the wafers to have a mirror-smooth surface, which requires the wafers to be polished on one or both sides after grinding.

[0003] The traditional wafer polishing process requires the following three steps to complete the polishing process: the first step is to use an adhesive with rosin as the main component to bond the wafer to a ceramic disc with a relatively large diameter and relatively high flatness. When bonding the wafer, the adhesive needs to be applied to the ceramic disc, the wafer is placed on the ceramic disc, and it is placed in an oven for heating. After heating for about 1 hour, the adhesive can be heated and melted into a liquid. The ceramic disc and the wafer are taken out of the oven together. Before the temperature drops completely and the adhesive is still liquid, a suitable tool is used to compact the wafer and the ceramic disc. The wafer and the ceramic disc are attached flat and are set aside after cooling; the second step is to install the ceramic disc with the bonded wafer on the polishing machine, the wafer face down in contact with the polishing pad, the polishing liquid is passed, and appropriate pressure is applied to perform planetary rotation polishing. The third step is to remove the polished wafer from the polishing machine together with the ceramic disc, put it into the oven for heating for about 1 hour, and heat the adhesive to melt it into a liquid. Then take the ceramic disc out of the oven, and remove the wafer from the ceramic disc before the temperature is completely lowered and the adhesive is still in a liquid state. It can be seen from the traditional polishing process that the wafer loading and unloading in the polishing process requires the use of adhesives, and both steps need to be heated in the oven, which takes a certain amount of time and consumes a certain amount of electricity. The loading and unloading process is relatively cumbersome. Without considering the time required for the polishing step, only the loading and unloading steps require at least 4 hours. In addition, when taking the wafer, the wafer and the ceramic disc are filled with adhesive, and the surfaces of the wafer and the ceramic disc are relatively flat. A vacuum is formed between the wafer and the ceramic disc, and it is not easy to remove the wafer from the surface of the ceramic disc. If the wafer diameter is relatively large, such as greater than or equal to 6 inches (Ф150mm), and the wafer thickness is relatively thin, such as less than or equal to 0.35mm, the wafer is easy to break if you are not careful when taking it out. After polishing the relatively thin quartz glass wafers, 5 out of 10 pieces will be broken, and the fragmentation rate is as high as 50%.

[0004] When using ferrite as a substrate (the thickness of the soft ferrite substrate currently used is generally 0.25-0.3mm, and the outer diameter of the disc is 76mm) to prepare a thin-film indium antimonide Hall element chip, a layer of indium antimonide film is vacuum evaporated on the ferrite disc. This indium antimonide film needs to be annealed at high temperature. After high-temperature annealing, a very thin oxide film will be formed on the surface of the indium antimonide film. This very thin oxide film needs to be polished and removed. In the optical industry, the glass surface needs to be polished, and in the mechanical industry, some parts also need to be polished, so polishing is a commonly used process in the semiconductor, optical, mechanical and other industries. When preparing thin-film indium antimonide Hall element chips, a soft ferrite thin wafer with a thickness of 0.25 to 0.3 mm and an outer diameter of 76 mm is required as a substrate. The ferrite wafer needs to be polished on one side. Ferrite wafers are more easily fragmented than single-crystal silicon wafers. If polished using traditional polishing methods, the fragmentation rate caused by wafer removal is as high as more than 50%, increasing the manufacturing cost of thin-film indium antimonide Hall element chips.

[0005] In summary, the traditional polishing method takes a long time to load and remove the wafers, requires adhesives and oven heating, increases energy consumption, and has the disadvantages of complicated loading and removing processes. For ferrite wafers that are thinner and more fragile, they are more likely to break when being removed, and face the problem of a fragmentation rate of more than 50%. Summary of the invention

[0006] The present invention provides a magnetic polishing fixture to solve the problems of long loading and unloading time, complicated process, high fragmentation rate of unloading, etc. in the traditional polishing method. In combination with the magnetic polishing fixture, the present invention also provides a matching planetary rotary polishing device that can start and stop slowly and can rotate forward and reverse.

[0007] The magnetic polishing fixture provided by the present invention includes a fixture body, a first stopper is provided on the front side of the fixture body, and the first stopper surface is used to place the workpiece to be polished; a plurality of blind holes are provided on the back side of the fixture body, and magnets are placed in the blind holes; after the workpiece to be polished is placed on the first stopper surface, the magnets placed in the blind holes can adsorb the workpiece to be polished on the first stopper surface.

[0008] In a preferred embodiment of the magnetic polishing fixture, a second stopper is provided on the back of the fixture body, the second stopper surface is used for placing a counterweight, and the blind holes are evenly distributed on the second stopper surface.

[0009] In a preferred embodiment of the magnetic polishing fixture, a through hole penetrating the first stop surface is provided on the bottom surface of each blind hole, and the through hole is used to prevent vacuum adsorption between the workpiece to be polished and the first stop surface.

[0010] In a preferred embodiment of the above-mentioned magnetic polishing fixture, the fixture body is a cylindrical or rectangular column structure.

[0011] In a preferred embodiment of the above-mentioned magnetic polishing fixture, the second stop surface is circular, and the blind holes are evenly arranged around the center of the second stop surface; and / or the number of the blind holes is 8-12.

[0012] In a preferred embodiment of the magnetic polishing fixture, the depth of the first stop is less than the thickness of the workpiece to be polished.

[0013] In a preferred embodiment of the above-mentioned magnetic polishing fixture, the outer edge of the side wall of the first stop is set to be rounded.

[0014] In a preferred embodiment of the above-mentioned magnetic polishing fixture, a handle is provided on the second stop surface, and the handle is used for an operator to take and place the magnetic polishing fixture.

[0015] In a preferred embodiment of the above-mentioned magnetic polishing fixture, a threaded through hole penetrating the second stop surface is provided at the center position of the first stop surface, and the threaded through hole is used to fix a screw; a countersunk hole is also provided on the first stop surface coaxially with the threaded through hole; after the screw is fixed in the threaded through hole, the head of the screw can be completely submerged in the countersunk hole, and the tail of the screw penetrates through and is higher than the second stop surface, so as to facilitate the operator to take and place the magnetic polishing fixture.

[0016] In a preferred embodiment of the magnetic polishing fixture, the magnet is a strong neodymium iron boron magnet, a strong ferrite magnet, or a magnet formed by an energized coil.

[0017] A polishing device provided by the present invention includes a central gear, planetary gears meshing with the central gear and an internal gear meshing with the planetary gears; the polishing device also includes a support plate, a polishing pad laid on the support plate and a first central gear pad placed on the polishing pad; the central gear is placed on the first central gear pad; there are at least three planetary gears, and each of the planetary gears is provided with at least one accommodating through hole for placing the above-mentioned polishing fixture; the polishing device also includes a driving motor, after the polishing fixture is placed in the accommodating through hole, the driving motor can drive the central gear to rotate, the central gear drives the planetary gears to rotate, and the planetary gears drive the magnetic polishing fixture to rotate, thereby generating friction between the workpiece to be polished located on the first stop surface and the polishing pad.

[0018] In a preferred embodiment of the above-mentioned polishing device, the polishing device also includes a first internal gear pad, which is provided with a circular hole slightly smaller than the inner diameter of the internal gear; the internal gear is placed on the first internal gear pad, and the planetary gear is placed on the upper surface of the first center gear pad and the first internal gear pad.

[0019] In a preferred embodiment of the above-mentioned polishing device, the upper and lower edges of the inner edge of the first internal gear pad are both chamfered; and / or the upper and lower edges of the outer edge of the first central gear pad are both chamfered.

[0020] In a preferred embodiment of the above-mentioned polishing device, the polishing device also includes a second center gear pad having the same structure as the first center gear pad, and the second center gear pad is used to cover the center gear from above; and / or, the polishing device also includes a second internal gear pad, and the second internal gear pad is used to cover the internal gear from above.

[0021] In a preferred embodiment of the above-mentioned polishing device, gaskets are provided on the lower surface of the second central gear pad and the lower surface of the second internal gear pad; the gaskets are used to create a gap between the second central gear pad and the second internal gear pad and the planetary gear.

[0022] In a preferred embodiment of the above-mentioned polishing device, at least one magnetic attraction head is provided on each of the planetary gears, and the magnetic attraction head is used to attract the magnetic particles ground off the workpiece to be polished.

[0023] In a preferred embodiment of the above-mentioned polishing device, each of the planetary gears is provided with four accommodating through holes for placing the above-mentioned magnetic polishing fixture; and / or each of the planetary gears is provided with four magnetic heads.

[0024] In a preferred embodiment of the above-mentioned polishing device, the polishing device also includes a polishing liquid spray assembly and a water-leakage-proof frame arranged along the outer edge of the support plate; the polishing liquid spray assembly is used to spray polishing liquid onto the polishing device; a transparent cover plate is arranged above the water-leakage-proof frame, and the transparent cover plate can prevent the polishing liquid from spilling out of the polishing device, and enable the operator to observe the working status of the polishing device through the transparent cover plate; a drain outlet is arranged below the water-leakage-proof frame, and the drain outlet is used to discharge the polishing liquid to the outside of the polishing device.

[0025] In a preferred embodiment of the above-mentioned polishing device, the polishing device also includes a control unit, a reed switch is arranged above the anti-leakage frame, and a magnet is arranged at a position corresponding to the reed switch on the transparent cover; the reed switch is electrically connected to the control unit, and when the transparent cover is opened, the magnet leaves the reed switch, thereby disconnecting the reed switch, and the control unit controls the polishing device to stop working according to the disconnection signal of the reed switch.

[0026] In a preferred embodiment of the above-mentioned polishing device, the polishing device further comprises a photoelectric position sensor, which is capable of recording the number of rotations of the central gear and sending the rotation number signal to the control unit.

[0027] In a preferred embodiment of the above-mentioned polishing device, the polishing pad has grid-like indentations; and / or, the driving motor is an adjustable speed motor; and / or, the driving motor can rotate clockwise and counterclockwise.

[0028] In a preferred embodiment of the above-mentioned polishing device, the polishing device can be used to polish the ferrite substrate material of the thin-film InSb Hall element chip.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The magnetic polishing fixture of the present invention uses magnetic force to place and take the film, and does not require the use of adhesives or oven heating, and can complete the film placement and film taking processes at room temperature. The strong NdFeB magnet can be used repeatedly, which reduces energy consumption, reduces the consumption of raw materials, and reduces production costs. Not only does it take less time in the process of taking and loading the film, but it also solves the problem that the traditional polishing machine uses adhesives to place and take the film and is prone to fragmentation. More specific beneficial effects are further described in detail in the specific implementation method below.

[0031] Solution 1: A magnetic polishing fixture, characterized in that the magnetic polishing fixture comprises a fixture body, a first stopper is provided on the front of the fixture body, and the first stopper surface is used to place the workpiece to be polished; a plurality of blind holes are provided on the back of the fixture body, and magnets are placed in the blind holes;

[0032] After the workpiece to be polished is placed on the first stop surface, the magnet placed in the blind hole can adsorb the workpiece to be polished on the first stop surface.

[0033] Solution 2: The magnetic polishing fixture according to Solution 1 is characterized in that a second stop is opened on the back side of the fixture body, the second stop surface is used to place a counterweight, and the blind holes are evenly distributed on the second stop surface.

[0034] Option 3: The magnetic polishing fixture according to Option 2 is characterized in that a through hole penetrating the first stop surface is opened on the bottom surface of each blind hole, and the through hole is used to prevent vacuum adsorption between the workpiece to be polished and the first stop surface.

[0035] Solution 4: The magnetic polishing fixture according to Solution 3 is characterized in that the fixture body is a cylindrical or rectangular column structure.

[0036] Option 5: The magnetic polishing fixture according to Option 4 is characterized in that the second stop surface is circular, and the blind holes are evenly arranged around the center of the second stop surface; and / or the number of the blind holes is 8-12.

[0037] Option 6: A magnetic polishing fixture according to any one of Options 1 to 5, characterized in that the depth of the first stop is less than the thickness of the workpiece to be polished.

[0038] Option 7: A magnetic polishing fixture according to any one of Options 1 to 5, characterized in that the outer edge of the side wall of the first stop is set as a rounded corner.

[0039] Option 8: A magnetic polishing fixture according to any one of Options 1 to 5, characterized in that a handle is provided on the second stop surface, and the handle is used by an operator to take and place the magnetic polishing fixture.

[0040] Solution 9: A magnetic polishing fixture according to any one of solutions 1 to 5, characterized in that a threaded through hole penetrating the second stop surface is provided at the center of the first stop surface, the threaded through hole being used to fix a screw; and a countersunk hole is also provided on the first stop surface coaxially with the threaded through hole;

[0041] After the screw is fixed in the threaded through hole, the head of the screw can be completely sunk in the countersunk hole, and the tail of the screw penetrates and protrudes above the second stop surface, which can facilitate the operator to take and place the magnetic polishing fixture.

[0042] Scheme 10: A magnetic polishing fixture according to any one of Schemes 1 to 5, characterized in that the magnet is a strong NdFeB magnet, a strong ferrite magnet or a magnet formed by an energized coil.

[0043] Solution 11, a polishing device, characterized in that the polishing device comprises a central gear, a planetary gear meshing with the central gear, and an internal gear meshing with the planetary gear; the polishing device also comprises a support plate, a polishing pad laid on the support plate, and a first central gear pad placed on the polishing pad; the central gear is placed on the first central gear pad;

[0044] There are at least three planetary gears, and each of the planetary gears is provided with at least one receiving through hole for placing the magnetic polishing fixture described in any one of schemes 1 to 10;

[0045] The polishing device also includes a driving motor. After the polishing fixture is placed in the accommodating through hole, the driving motor can drive the central gear to rotate, and the central gear drives the planetary gears to rotate, and the planetary gears drive the polishing fixture to rotate, thereby generating friction between the workpiece to be polished located on the first stop surface and the polishing pad.

[0046] Solution 12: The polishing device according to Solution 11 is characterized in that the polishing device further comprises a first internal gear pad, and a circular hole slightly smaller than the inner diameter of the internal gear is formed on the first internal gear pad;

[0047] The internal gear is placed on the first internal gear backing plate, and the planetary gears are placed on upper surfaces of the first sun gear backing plate and the first internal gear backing plate.

[0048] Solution 13: The polishing device according to Solution 12 is characterized in that the upper and lower edges of the inner edge of the first internal gear pad are both chamfered; and / or,

[0049] The upper side and the lower side of the outer edge of the first central gear backing plate are both chamfered.

[0050] Solution 14: The polishing device according to Solution 13 is characterized in that the polishing device also includes a second central gear pad having the same structure as the first central gear pad, and the second central gear pad is used to cover the central gear from above;

[0051] And / or, the polishing device further comprises a second internal gear pad, and the second internal gear pad is used for covering the internal gear from above.

[0052] Solution 15: The polishing device according to Solution 14 is characterized in that the lower surface of the second central gear pad and the lower surface of the second internal gear pad are both provided with gaskets;

[0053] The gasket is used to allow a gap to exist between the second sun gear backing plate, the second internal gear backing plate and the planetary gear.

[0054] Solution 16. The polishing device according to Solution 11 is characterized in that each of the planetary gears is provided with at least one magnetic attraction head, and the magnetic attraction head is used to absorb the magnetic particles ground off the workpiece to be polished.

[0055] Scheme 17. The polishing device according to Scheme 16 is characterized in that each of the planetary gears is provided with four accommodating through holes for placing the polishing fixture described in any one of Schemes 1 to 10; and / or each of the planetary gears is provided with 4 magnetic heads.

[0056] Solution 18: The polishing device according to Solution 16 is characterized in that the polishing device further comprises a polishing liquid spraying assembly and a water-leakage-proof frame arranged along the outer edge of the support plate;

[0057] The polishing liquid spraying assembly is used to spray polishing liquid onto the polishing device;

[0058] A transparent cover is provided above the anti-leakage frame, and the transparent cover can prevent the polishing liquid from spilling out of the polishing device, and allows the operator to observe the working state of the polishing device through the transparent cover;

[0059] A drain port is provided below the anti-leakage frame, and the drain port is used to discharge the polishing liquid out of the polishing device.

[0060] Solution 19: The polishing device according to Solution 18 is characterized in that the polishing device further comprises a control unit, a reed switch is arranged above the water leakage prevention frame, and a magnet is arranged at a position on the transparent cover plate corresponding to the reed switch;

[0061] The reed switch is electrically connected to the control unit. When the transparent cover is opened, the magnet leaves the reed switch, thereby disconnecting the reed switch. The control unit controls the polishing device to stop working according to the disconnection signal of the reed switch.

[0062] Option 20. The polishing device according to Option 19 is characterized in that the polishing device also includes a photoelectric position sensor, which can record the number of rotations of the central gear and send the rotation number signal to the control unit.

[0063] Solution 21. A polishing device according to any one of solutions 11 to 20, characterized in that the polishing pad has a grid-like indentation;

[0064] And / or, the driving motor is an adjustable speed motor;

[0065] And / or, the drive motor is capable of clockwise rotation and counterclockwise rotation.

[0066] Scheme 22. The polishing device according to Scheme 21 is characterized in that the polishing device can be used to polish the ferrite substrate material of the thin-film indium antimonide Hall element chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1a It is a front oblique view of a magnetic polishing fixture according to an embodiment of the present invention;

[0068] Figure 1b It is a rear oblique view of a magnetic polishing fixture according to an embodiment of the present invention;

[0069] Figure 1c It is a front view of the magnetic polishing fixture of the present invention after adsorbing the workpiece to be polished;

[0070] Figure 2a It is a rear elevation view of a magnetic polishing fixture according to an embodiment of the present invention;

[0071] Figure 2b along Figure 2a Sectional view in the AA direction;

[0072] Figure 2c yes Figure 2b A partial enlarged view of the middle B area;

[0073] Figure 3 It is a rear oblique view of a magnetic polishing fixture with a center screw according to an embodiment of the present invention;

[0074] Figure 4 is a front view of a polishing device according to an embodiment of the present invention (the polishing fixture is not provided with a counterweight, and the second central gear pad and the second internal gear pad are omitted);

[0075] Figure 5 is a front view of a polishing device according to an embodiment of the present invention (the polishing fixture is without a counterweight, and the second sun gear pad and the second internal gear pad are shown);

[0076] Figure 6 It is a front view of a polishing device according to an embodiment of the present invention (the polishing fixture has a counterweight, and the second sun gear pad and the second internal gear pad are shown).

[0077] Figure markings: 1- fixture body, 11- first stop, 12- second stop, 13- blind hole, 14- through hole, 15- threaded through hole, 16- countersunk hole; 2- center gear, 21- first center gear pad, 22- second center gear pad; 3- planetary gear, 31- receiving through hole, 32- magnetic head; 4- internal gear, 41- first internal gear pad, 42- second internal gear pad; 5- polishing pad. DETAILED DESCRIPTION

[0078] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0079] In order to clearly explain the specific implementation of the present invention, the following description is made by taking ferrite as an example of the workpiece to be polished. In this embodiment, the workpiece to be polished is a ferrite circular sheet with an outer diameter of 76 mm and a thickness of 0.25-0.3 mm. The present invention utilizes the property that the ferrite circular sheet can be adsorbed by a magnet. In addition to ferrite, the workpiece to be polished of the present invention can also be a material that can be adsorbed by a magnetic force, such as iron, silicon steel, permalloy, and nebulium iron boron.

[0080] First refer to Figure 1a-1c , Figure 1a-1c The following are the front oblique view, the back oblique view and the front view of the magnetic polishing fixture after adsorbing the workpiece to be polished according to an embodiment of the present invention. Figure 1a-1c As shown, the magnetic polishing fixture of the present invention includes a fixture body 1, a first stopper 11 is provided on the front of the fixture body 1, and the first stopper surface is used to place ferrite; a plurality of blind holes 13 are provided on the back of the fixture body 1, and the blind holes 13 are used to place magnets. As an example, a second stopper 12 can also be provided on the back of the fixture body 1, and the blind holes 13 are provided on the second stopper surface. The second stopper surface is used to place a counterweight ( Figure 6 The balancing weight placed on the second stop surface is shown in the figure, and the balancing weight is used to increase the weight of the fixture body 1, thereby increasing the friction. After the ferrite is placed on the first stop surface, the magnet placed in the blind hole 13 can adsorb the ferrite on the first stop surface.

[0081] Specifically, the shape of the magnetic polishing fixture of the present invention can be set as a cylindrical structure or a rectangular cylindrical structure. The magnetic polishing fixture can also be set to other suitable shapes such as rhombus, special-shaped body, etc. according to actual needs by those skilled in the art. The present invention does not limit the shape of the magnetic polishing fixture. The material of the magnetic fixture can be 304# or 316# stainless steel, aluminum alloy, nylon, epoxy resin, plastic and other materials that do not adsorb magnetic fields. The magnetic polishing fixture of this embodiment is a cylindrical structure made of 304# stainless steel. Specifically, a fixture body 1 with an outer diameter of 80mm and a length of 50mm is turned with 304# stainless steel bar stock, and then a first stop 11 with a depth of 0.2mm and a diameter of 76.4mm is turned on a plane of the fixture body 1 (the front of the fixture body 1), and the first stop 11 is concentric with the front of the fixture body 1. Ferrite discs can be placed on the plane of the first stop 11 (i.e., the first stop surface). A second stopper 12 with a diameter of 75 mm and a depth of 10 mm is machined on another plane of the clamp body 1 (the back of the clamp body 1), and the second stopper 12 is concentric with the back of the clamp body 1. The plane of the second stopper 12 (i.e., the second stopper surface) can be used to place a counterweight.

[0082] Reference Figure 1b , the blind holes 13 are evenly distributed on the second stop surface. In the present embodiment, the number of the blind holes 13 is 8, and they are evenly arranged around the center of the second stop surface. In some embodiments, the number of the blind holes 13 can also be set to other suitable numbers, such as 10 or 12. It should be noted here that since the blind holes 13 are evenly arranged on the second stop surface, when a magnet is placed in the blind hole 13, the magnet can generate a uniform adsorption force on the edge of the ferrite disc placed on the first stop surface. For example, when 8 blind holes are set, the 8 blind holes can be evenly arranged on a circumference with a diameter of 60mm that is cocentric with the second stop surface. In other words, the 8 blind holes 13 are evenly arranged around the outer edge of the second stop surface, which can not only ensure that the ferrite is subjected to a uniform adsorption force, but also avoid the ferrite from warping. It is also possible to evenly arrange 4 more blind holes 13 on a circumference with a diameter of 30mm that is cocentric with the second stop surface, and these do not deviate from the protection scope of the present invention.

[0083] As an example, the diameter of each blind hole 13 can be 10.2 mm and the depth can be 49.3 mm. The magnet in the blind hole 13 can be a strong NdFeB magnet, and the thickness of the strong NdFeB magnet can be 4 mm. It should be noted that the magnet of the present invention can be selected by those skilled in the art according to actual needs. Any suitable strong magnet can be selected as long as the purpose of adsorbing the workpiece to be polished can be achieved. For example, in addition to the strong NdFeB magnet, the magnet of the present invention can also be a strong ferrite magnet, and the strong magnetic force generated after the coil is energized can also be used as a magnet to adsorb the workpiece to be polished.

[0084] Reference Figure 2a , Figure 2a FIG. 1 is a front view of the back of a magnetic polishing fixture according to an embodiment of the present invention. Figure 2a As shown, the bottom surface of each blind hole 13 is provided with a through hole 14 penetrating the first stop surface, and the through hole 14 is a circular hole with a diameter of 2 mm, and the through hole 14 is coaxial with the blind hole 13. The through hole 14 is used to prevent vacuum adsorption between the ferrite and the first stop surface. Specifically, when the ferrite disc is polished and taken out, these through holes 14 can act as vent holes to prevent vacuum adsorption between the ferrite disc and the first stop surface due to the polishing liquid. In other words, with these through holes 14, the ferrite disc can be easily taken out.

[0085] Reference Figure 2b and 2c , Figure 2b along Figure 2a Sectional view along the AA direction, Figure 2c yes Figure 2b A partial enlarged view of area B in the figure. Figure 2b and 2c As shown, the outer edge of the side wall of the first stop 11 is set to be rounded, that is, Figure 2c The radius of the fillet can be set to 0.5 mm, and those skilled in the art can also set the radius of the fillet to 0.1-1 mm or other reasonable sizes according to actual design requirements. The fillet can prevent the sharp corners of the fixture body 1 from scratching the polishing pad (the polishing pad will be further described below) when the fixture body 1 rotates, and can also reduce the friction resistance other than the workpiece to be polished. In addition, the other corners of the fixture body 1 can also be blunted.

[0086] More specifically, the depth of the first stop is usually slightly smaller than the thickness of the body to be polished. In the present embodiment, the thickness of the ferrite disc to be polished is 0.25-0.3 mm, so the depth of the first stop can be set to be less than 0.25 mm, for example, 0.2 mm. Preferably, the first stop surface needs to be rounded. The thickness between the bottom of the blind hole 13 and the first stop surface is 0.5 mm (can also be less than 0.5 mm). This design is to ensure that the magnet in the blind hole 13 can give the ferrite located on the first stop surface maximum adsorption force. Preferably, the bottom surface of the blind hole 13 needs to be rounded.

[0087] The operation mode of inserting ferrite in the magnetic polishing fixture of the present invention is as follows: first, the first stop surface 11 is upward, and the ferrite circular sheet is inserted, and the ferrite plane is parallel to the first stop surface 11 (because the inner diameter of the first stop surface is 76.4mm, and the outer diameter of the ferrite is 76mm, the ferrite can be placed in the first stop surface; the thickness of the ferrite is 0.25-0.3mm, and the depth of the first stop surface 11 is 0.2mm. After the ferrite is installed, one surface of the ferrite should be about 0.05-0.1mm higher than the fixture body). Then, use the left hand to protect the ferrite circular sheet to prevent the ferrite circular sheet from falling, and then turn the fixture body 1 over so that its back is facing up. At this time, use the right hand to insert a NdFeB strong magnet into each blind hole 13 of the second stop surface, and use the characteristic of the NdFeB strong magnet to absorb ferrite to firmly absorb the ferrite on the first stop surface. At this time, release the left hand, and the ferrite circular sheet will not fall. The front view of the fixture body 1 after adsorbing the ferrite is shown in FIG. Figure 1c shown.

[0088] In a specific embodiment, return to reference Figure 1a and 1b A threaded through hole 15 penetrating the second stop surface is provided at the center of the first stop surface, and the threaded through hole 15 is used to fix the screw; a countersunk hole 16 is also provided on the first stop surface coaxially with the threaded through hole 15; after the screw is fixed in the threaded through hole 15, the head of the screw can be completely submerged in the countersunk hole 16. This design ensures that the head of the screw will not exceed the first stop surface, that is, it will not affect the adsorption of the first stop surface and the ferrite. The part of the tail of the screw that penetrates the second stop surface can facilitate the operator to take and place the magnetic polishing fixture. Figure 3 , Figure 3 FIG. 1 is a rear oblique view of a magnetic polishing fixture with a center screw according to an embodiment of the present invention. Figure 3 As shown, the screw protruding from the center of the second stop surface can be used as a handle to facilitate operators to take and place the magnetic polishing fixture. As an example, the threaded through hole 15 is suitable for an M6 semicircular head cross screw, and the countersunk hole 16 can have a diameter of 12 mm and a depth of 8 mm.

[0089] Alternatively, the threaded through hole 15 and the countersunk hole 16 may not be provided at the center of the first stop surface, and only a handle needs to be provided on the second stop surface, which can also achieve the purpose of facilitating the operator to take and place the magnetic polishing fixture. The present invention does not limit the specific structure and form of the handle. In other words, those skilled in the art can flexibly set the structure of the handle according to actual needs, which does not deviate from the protection scope of the present invention.

[0090] The present invention also provides a polishing device. Figure 4 , Figure 4 1 is a front view of a polishing device according to an embodiment of the present invention (the polishing fixture does not have a counterweight, and the second central gear pad and the second internal gear pad are omitted). Figure 4 As shown, the polishing device of the present invention includes a planetary gear rotating mechanism composed of a central gear 2, planetary gears 3 and an internal gear 4 (there are three planetary gears 3 in this embodiment), wherein the central gear 2 is meshed with the planetary gears 3, and the planetary gears 3 are meshed with the internal gear 4. The polishing device also includes a support plate ( Figure 4 ), a polishing pad 5 laid on the support plate and a first central gear pad 21 placed on the polishing pad 5, the outer diameters of the first central gear pad 21 and the second central gear pad 22 are larger than the outer diameter of the central gear 2, and the central gear 2 is placed on the first central gear pad 21. Each planetary gear 3 is provided with a receiving through hole 31 for placing the above-mentioned magnetic polishing fixture. In this embodiment, four receiving through holes 31 are evenly arranged on each planetary gear 3. The polishing device also includes a drive motor ( Figure 4 (not shown in the figure), after the polishing fixture is placed in the accommodating through hole 31, the driving motor can drive the central gear 2 to rotate, the central gear 2 drives the planetary gear 3 to rotate, and the planetary gear 3 drives the magnetic polishing fixture to rotate, thereby causing friction between the ferrite located on the first stop surface and the polishing pad 5, that is, polishing the ferrite.

[0091] Furthermore, the polishing device further comprises a first internal gear pad 41, on which a large circular hole slightly smaller than the inner diameter of the internal gear 4 is formed. The internal gear 4 is placed on the first internal gear pad 41, and the planetary gear 3 is placed on the upper surfaces of the first sun gear pad 21 and the first internal gear pad 41.

[0092] Specifically, a support plate can be made of a nylon material with the same outer dimensions as the inner gear 4 and a thickness of 20 mm, a polishing pad 5 with a grid-shaped indentation of the same size as the support plate and a thickness of about 5 mm is laid on the support plate, and a first inner gear pad 41 with the same outer dimensions as the support plate and a thickness of 20 mm is placed on the polishing pad 5, and a large circular hole is opened in the center of the first inner gear pad, and the inner diameter of the large circular hole is smaller than the inner diameter of the inner gear 4. A first central gear pad 21 is placed at the center of the polishing pad 5, and a through hole with a diameter of 10.5 mm and a keyway matching the central gear 2 are made in the center of the central gear pad 21, and the central gear 2 is placed on the central gear pad 21. Three planetary gears 3 are evenly placed between the inner gear 4 and the central gear 2, and the planetary gears 3 are placed on the upper surfaces of the first central gear pad 21 and the first inner gear pad 41. In other words, one central gear, three planetary gears and one inner gear are all on the plane formed by the first inner gear pad 41 and the first central gear pad 21.

[0093] It can be understood by those skilled in the art that, according to the structural design of the polishing device of the present invention, the polishing pad 5 and the magnetic polishing fixture 1 no longer require a precise matching design. In other words, when the polishing device of the present invention is performing a polishing operation, the polishing pad 5 only needs to be laid on the support plate, and then the front of the magnetic polishing fixture 1 can be directly pressed on the polishing pad 5. In this way, during the rotation of the magnetic polishing fixture 1, the ferrite disc on the first stop surface can contact the polishing pad 5 and generate friction. However, existing polishing machines often require precise design of the mechanical fit between the polishing pad and the polishing fixture, which undoubtedly increases the design and processing costs. Compared with the prior art, the polishing device of the present invention no longer requires a precise matching design, which can greatly save mechanical design and processing costs.

[0094] Furthermore, in order to ensure smooth rotation and easy installation of the planetary gear 3, a 10mm and 5mm chamfer can be set on the upper and lower edges of the inner edge of the first internal gear pad 41 respectively; and a 10mm and 5mm chamfer can be set on the upper and lower edges of the outer edge of the first central gear pad 21 respectively.

[0095] In a specific embodiment, referring to Figure 5 , Figure 5 1 is a front view of a polishing device according to an embodiment of the present invention (the polishing fixture does not have a counterweight, and the second central gear pad and the second internal gear pad are shown). Figure 5As shown, the polishing device of the present invention also includes a second central gear pad 22 and a second internal gear pad 42 having the same structure as the first central gear pad 21. The second central gear pad 22 is used to cover the central gear 2 from above, and the second internal gear pad 42 is used to cover the internal gear 4 from above. In this way, the center of a support plate, a polishing pad 5, two central gear pads (the first central gear pad 21 and the second central gear pad 22) and a central gear 2 can be fixed to the center of the support plate through a central shaft made of 304# stainless steel with a keyway structure. A support plate, a polishing pad 5, two internal gear pads (the first internal gear pad 41 and the second internal gear pad 42) and an internal gear are aligned on all sides, and these components can be locked and fixed with screws and nuts through the through holes on the edges. The internal gear 4 and the central gear 2 are fixed by the above method, and the planetary gear 3 is positioned up and down by two central gear pads (the first central gear pad 21 and the second central gear pad 22) and two internal gear pads (the first internal gear pad 41 and the second internal gear pad 42), and the circumference of the planetary gear 3 is positioned by gear meshing with the central gear 2 and the internal gear 4. The outer edges of the first and second central gear pads 22 and the inner edges of the first and second internal gear pads 42 are also chamfered, which can make the planetary gears rotate smoothly and prevent the two central gear pads and the two internal gear pads from being pressed tightly and unable to rotate after the planetary gear 3 is fixed.

[0096] As an example, the driving motor provided by the present invention is an adjustable speed motor. A planetary rotating structure is formed under the drive of the adjustable speed motor. The specific connection and installation method between the adjustable speed motor and the central gear mechanism will not be described in detail here, and those skilled in the art can flexibly set it according to actual conditions. Preferably, when the planetary gears rotate, the outer edges of the four accommodating through holes 31 evenly distributed on each planetary gear do not intersect or tangent with the outer edges of the two central gear pads or the outer edges of the inner holes of the two inner gear pads to ensure that the polishing device does not collide with these pads. It should be noted that when starting the driving motor, if the driving motor starts very quickly and the speed quickly reaches the rated speed of the driving motor, the friction force at this time is relatively large, and the ferrite disc can easily slide out of the first stop surface, and the ferrite sheet that slides out of the first stop surface can easily be collided and broken. For this reason, a slow start and slow stop method is adopted to solve this problem. Specifically, since the drive motor is an adjustable speed motor, a PLC (programmable controller) can be used to control the adjustable speed motor. When the drive motor is started, the drive motor can be started slowly, such as reaching the rated speed within 1 minute; similarly, when the drive motor is turned off, the drive motor can be stopped slowly, such as stopping rotation within 1 minute. Slow start and slow stop are used each time the drive motor is started or stopped, so that the problem that the ferrite disc sheet easily slides out of the first stop surface can be effectively solved.

[0097] As an example, the adjustable speed motor can rotate both clockwise and counterclockwise (i.e., the motor can rotate forward and reverse). This design allows the polishing device to flexibly control the rotation direction of the motor during the polishing operation. For example, the motor can be controlled to rotate clockwise for 30 minutes, stop for 10 seconds, then rotate counterclockwise for 30 minutes, and then stop for 10 seconds. This cycle can be repeated to make the polishing of the ferrite disc more uniform.

[0098] As a preferred embodiment, a gasket is provided on the lower surface of the second sun gear pad 22 and the lower surface of the second internal gear pad 42, and the gasket is used to provide a gap between the second sun gear pad 22 and the second internal gear pad 42 and the planetary gear 3, and the gap can ensure smooth rotation of the planetary gear 3 and prevent the two sun gear pads and the two internal gear pads from being pressed and unable to rotate after the planetary gear 3 is fixed. As an example, the thickness of the gasket can be 1 mm.

[0099] In a specific embodiment, continue to refer to Figure 4 and 5 , at least one magnetic head 32 is provided on the planetary gear 3, and the magnetic head 32 is used to absorb the magnetic particles ground from the ferrite. Specifically, in this embodiment, four receiving through holes 31 are evenly provided on each planetary gear 3, and the number of the magnetic heads 32 is also evenly set to four, and the magnetic heads 32 and the receiving through holes 31 are staggered. By using the magnetic head 32 to absorb the magnetic powder particles ground from the ferrite disc by the polishing device onto the magnetic head, the polishing effect of the ferrite disc can be better.

[0100] As an example, see Figure 6 , Figure 6 FIG. 2 is a front view of a polishing device according to another embodiment of the present invention (the polishing fixture is provided with a counterweight, and the second central gear pad and the second internal gear pad are shown). Figure 6 As shown, a counterweight is placed on the second stop surface of the polishing fixture. Those skilled in the art can calculate the weight of the counterweight that needs to be added according to the friction force that needs to be applied.

[0101] In a specific embodiment, the polishing device further includes a polishing liquid spray assembly and a water-leakage-proof frame arranged along the outer edge of the support plate. The polishing liquid spray assembly is used to spray polishing liquid onto the polishing device; a transparent cover is arranged above the water-leakage-proof frame, which can prevent the polishing liquid from spilling out of the polishing device and allow the operator to observe the working status of the polishing device through the transparent cover; a drain is arranged below the water-leakage-proof frame, which is used to discharge the polishing liquid out of the polishing device. Although the structural schematic diagram of the spray assembly, water-leakage-proof frame, transparent cover and drain is not shown in the accompanying drawings, it can be understood by those skilled in the art that these components can increase the safety of the polishing device during the process of polishing ferrites, and the specific structural settings of the supporting devices or auxiliary equipment can be flexibly set according to the actual application scenarios. For example, the spray assembly can be installed on the transparent cover so that the spray port is located above the second center gear pad 22, and a water pump (belonging to the spray assembly) is installed in the bucket containing the polishing liquid. The water pump draws the polishing liquid in the bucket through the water pipe to the spray port, and the polishing liquid is sprayed into the polishing device through the spray port. During the polishing operation of the polishing device, the polishing liquid is discharged to the anti-leakage frame, and the polishing liquid collected by the anti-leakage frame flows into the bucket containing the polishing liquid outside the polishing device through the drain port and the water pipe. The water pump then draws the polishing liquid through the water pipe to the spray pipe port, thus forming a circulation of the polishing liquid, and the polishing liquid can be used repeatedly.

[0102] Furthermore, a reed switch can be installed on the anti-leakage frame, and a magnet, such as a strong NdFeB magnet, can be installed at the corresponding position of the transparent cover. When the transparent cover is opened, the strong NdFeB magnet leaves the reed switch, the reed switch is disconnected, the PLC automatically stops the rotation of the drive motor, and stops the water pump. This can prevent the corrosive polishing liquid from spilling to the outside. At the same time, the center gear and the planetary gears stop rotating to avoid squeezing the operator's fingers.

[0103] Furthermore, a photoelectric position sensor may be provided on the polishing device of the present invention, and the photoelectric position sensor is used to record the number of rotations of the central gear 2 and transmit the number to the PLC controller to realize automatic control of the polishing device.

[0104] If the thin-film InSb Hall element chip is used for linear measurement, the substrate used is a non-magnetic substrate, and a single crystal silicon wafer, a quartz glass wafer or a ceramic wafer can be used; if it is used in a switching application, such as a DC brushless motor, the substrate needs to use a magnetic substrate of a soft ferrite material to converge the external magnetic field to the InSb sensitive layer to obtain a higher magnetic field intensity. Therefore, when the InSb Hall element chip is used in a switching application, the polishing device of the present invention can be used to polish the ferrite substrate material of the thin-film InSb Hall element chip.

[0105] As described above, in this embodiment, the polishing device can polish 12 ferrite discs at a time. It takes less than 30 seconds for each polishing fixture to install a ferrite disc. When taking out the disc, another NdFeB strong magnet is used to absorb the NdFeB magnet installed in the blind hole 13, which takes even less time, less than 10 seconds, to remove the NdFeB strong magnets in all the blind holes of a fixture body 1. It takes less than 6 minutes to install 12 ferrite discs; it takes less than 3 minutes to remove 12 ferrite discs after polishing. The total time for loading and removing the discs is about 10 minutes. Compared with the traditional polishing device, which takes at least 4 hours to load and remove the discs, the efficiency is improved by more than 24 times.

[0106] The polishing device of the present invention uses magnetic force to place and take the sheet, does not need to use adhesives, does not need to be heated in an oven, and can complete the sheet placing and taking process at room temperature. The strong NdFeB magnet can be used repeatedly, which reduces energy consumption, reduces the consumption of raw materials, reduces production costs, and solves the problem that the traditional polishing machine is easy to break when taking the sheet using adhesives.

[0107] In addition, most of the parts of the polishing device of this embodiment are made of nylon. The overall structure of the polishing device is relatively light, and the total weight does not exceed 400 kilograms. It can be placed on a general load-bearing floor. The traditional polishing machine is relatively heavy and can generally only be placed on the first floor. If it is placed on the second floor or above, it is necessary to increase the load-bearing design and structure of the building, which increases the cost of equipment use. The central gear, planetary gear, internal gear, two internal gear pads, support plate and other parts of this embodiment are made of nylon. When the central gear and planetary gear rotate, they can be lubricated by polishing liquid without adding additional lubricating oil, thereby avoiding the contamination of the ferrite disc by lubricating oil. In addition, the planetary rotating structure composed of the central gear, planetary gear and internal gear is relatively light. Only one adjustable speed motor with a power of 800W is needed to drive the central gear and planetary gear to rotate. The polishing fixture is equipped with a counterweight and 12 polishing fixtures are installed. The motor power can meet the use. Traditional polishing machines require 5 motors, 4 of which drive 4 ceramic discs respectively, and 1 motor with relatively high power drives the large disc below to rotate. The structure is relatively complicated, which increases the weight of the polishing machine and also increases energy consumption.

[0108] The polishing device of the present invention also does not require a ceramic disc with a relatively high flatness. Ceramic discs are relatively large in size. A general ceramic disc has an outer diameter of about 400 to 500 mm, a thickness of about 20 mm, and a weight of about 7 kg, which is relatively heavy. Importantly, the manufacturing cost of such a ceramic disc is relatively high. In addition, when in use, if it is accidentally dropped on the ground, it is easy to break, while the fixture body, planetary gears and other components of the present invention are durable.

[0109] The polishing device of the present invention can be stopped at any time to check the polishing effect, which is extremely convenient compared with the traditional polishing machine. It also has the functions of slow start, slow stop, clockwise and counterclockwise rotation. Sometimes it is necessary to temporarily stop the machine to check the polishing effect. If the polishing time is used as the mark of the end of polishing, it is inaccurate and the effect is not good. Generally speaking, during the planetary rotation polishing process, whether it is forward or reverse, fast or slow, the distance that the ferrite disc passes through on the polishing pad is proportional to the number of times the center gear rotates one circle. The polishing effect of the ferrite disc corresponds to the number of times the center gear rotates. PLC is used to record the number of rotations of the center groove wheel, and according to experience, the total number of rotations of the center groove wheel is set. When the cumulative number of rotations of the center groove wheel recorded by the PLC is equal to the total number, the polishing machine can be automatically stopped, the motor can be stopped, and the water pump can be stopped, so that the automation of the polishing process is realized.

[0110] Although the present invention is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A magnetic polishing fixture, used in wafer polishing process, characterized in that: The magnetic polishing fixture comprises a fixture body, a first stopper is provided on the front of the fixture body, and the first stopper surface is used to place the workpiece to be polished; a plurality of blind holes are provided on the back of the fixture body, and the first magnet is placed in the blind holes; After the workpiece to be polished is placed on the first stop surface, the first magnet placed in the blind hole can adsorb the workpiece to be polished on the first stop surface; A second stopper is provided on the back of the clamp body, and the blind holes are evenly distributed on the second stopper surface of the second stopper; A through hole penetrating the first stop surface is provided on the bottom surface of each blind hole, and the through hole is used to prevent vacuum adsorption from occurring between the workpiece to be polished and the first stop surface; Wherein, the depth of the first stop is less than the thickness of the workpiece to be polished; and the outer edge of the side wall of the first stop is set as a rounded corner.

2. The magnetic polishing fixture according to claim 1, characterized in that: The second stop surface is used for placing a counterweight.

3. The magnetic polishing fixture according to claim 1, characterized in that: The clamp body is in a cylindrical or rectangular column structure.

4. The magnetic polishing fixture according to claim 1, characterized in that: The second stop surface is circular, and the blind holes are evenly arranged around the center of the second stop surface; and / or, the number of the blind holes is 8-12.

5. The magnetic polishing fixture according to any one of claims 1 to 4, characterized in that: The second stop surface is provided with a handle, and the handle is used for an operator to take and place the magnetic polishing fixture.

6. The magnetic polishing fixture according to any one of claims 1 to 4, characterized in that: A threaded through hole penetrating the second stop surface is provided at the center of the first stop surface, and the threaded through hole is used to fix a screw; a countersunk hole is also provided on the first stop surface coaxially with the threaded through hole; After the screw is fixed in the threaded through hole, the head of the screw can be completely sunk in the countersunk hole, and the tail of the screw penetrates and protrudes above the second stop surface, which can facilitate the operator to take and place the magnetic polishing fixture.

7. The magnetic polishing fixture according to any one of claims 1 to 4, characterized in that: The first magnet is a strong NdFeB magnet, a strong ferrite magnet or a magnet formed by an energized coil.

8. A polishing device, used in wafer polishing process, characterized in that: The polishing device comprises a central gear, a planetary gear meshing with the central gear, and an internal gear meshing with the planetary gear; the polishing device also comprises a support plate, a polishing pad laid on the support plate, and a first central gear pad placed on the polishing pad; the central gear is placed on the first central gear pad; The polishing device further comprises a first internal gear pad, the internal gear is placed on the first internal gear pad, and the planetary gear is placed on the upper surface of the first sun gear pad and the first internal gear pad; There are at least three planetary gears, and each of the planetary gears is provided with at least one receiving through hole for accommodating the magnetic polishing fixture according to any one of claims 1 to 7; The polishing device also includes a driving motor. After the polishing fixture is placed in the accommodating through hole, the driving motor can drive the central gear to rotate, and the central gear drives the planetary gears to rotate, and the planetary gears drive the polishing fixture to rotate, thereby generating friction between the workpiece to be polished located on the first stop surface and the polishing pad.

9. The polishing device according to claim 8, characterized in that: The upper and lower edges of the inner edge of the first internal gear backing plate are both chamfered; and / or, The upper side and the lower side of the outer edge of the first central gear backing plate are both chamfered.

10. The polishing device according to claim 9, characterized in that: The polishing device further comprises a second sun gear pad having the same structure as the first sun gear pad, the second sun gear pad being used to cover the sun gear from above; And / or, the polishing device further comprises a second internal gear pad, and the second internal gear pad is used for covering the internal gear from above.

11. The polishing device according to claim 10, characterized in that: The lower surface of the second sun gear backing plate and the lower surface of the second internal gear backing plate are both provided with gaskets; The gasket is used to allow a gap to exist between the second sun gear backing plate, the second internal gear backing plate and the planetary gear.

12. The polishing device according to claim 8, characterized in that: At least one magnetic attraction head is arranged on each of the planetary gears, and the magnetic attraction head is used to attract the magnetic particles ground off the workpiece to be polished.

13. The polishing device according to claim 12, characterized in that: Each of the planetary gears is provided with four receiving through holes for accommodating the polishing fixture according to any one of claims 1 to 7; and / or each of the planetary gears is provided with four magnetic attracting heads.

14. The polishing device according to claim 12, characterized in that: The polishing device also includes a polishing liquid spraying assembly and a water-leakage-proof frame arranged along the outer edge of the support plate; The polishing liquid spraying assembly is used to spray polishing liquid onto the polishing device; A transparent cover is provided above the anti-leakage frame, and the transparent cover can prevent the polishing liquid from spilling out of the polishing device, and enables the operator to observe the working state of the polishing device through the transparent cover; A drain port is provided below the anti-leakage frame, and the drain port is used to discharge the polishing liquid out of the polishing device.

15. The polishing device according to claim 14, characterized in that: The polishing device also includes a control unit, a reed switch is arranged above the water leakage prevention frame, and a second magnet is arranged at a position corresponding to the reed switch on the transparent cover; The reed switch is electrically connected to the control unit. When the transparent cover is opened, the second magnet leaves the reed switch, thereby disconnecting the reed switch. The control unit controls the polishing device to stop working according to the disconnection signal of the reed switch.

16. The polishing device according to claim 15, characterized in that: The polishing device further comprises a photoelectric position sensor, which is capable of recording the number of rotations of the central gear and sending a rotation number signal to the control unit.

17. The polishing device according to any one of claims 8 to 16, characterized in that: The polishing pad has grid-like indentations; And / or, the driving motor is an adjustable speed motor; And / or, the drive motor is capable of clockwise rotation and counterclockwise rotation.

18. The polishing device according to claim 17, characterized in that: The polishing device can be used to polish the ferrite substrate material of the thin-film indium antimonide Hall element chip.

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