Wafer mirror polishing device and method

Abstract

The present invention discloses a wafer mirror polishing device and method, aiming to solve the problem that when a multi-piece polishing machine is used to polish a wafer in the prior art, the wafer thickness and total thickness deviation are difficult to control, thereby affecting the consistency of the quality of the substrate and the wafer, and reducing the production efficiency. The present invention solves the above technical problems through the following technical solutions: comprising: a bearing slide, a bearing platform that moves along its length direction is arranged on the bearing slide, and a rotatable wafer vacuum suction cup is arranged on the bearing slide; a rough polishing spindle and a fine polishing spindle are arranged in sequence above the bearing slide along its length direction, and the rough polishing spindle and the fine polishing spindle both move along their own axial direction; a wafer thickness gauge and a polishing pad finisher are arranged on the bearing slide, and the polishing pad finisher includes a brush disk.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer polishing, and more specifically, to a wafer mirror polishing device and method. Background Art

[0002] A wafer is a smooth, round, mirror-like sheet of material that is used in the chip production process. Its main production and processing steps include slicing, grinding, and polishing.

[0003] In the prior art, wafer polishing is mainly performed by large multi-wafer polishing machines. Taking 12-inch silicon wafers as an example, a large polishing machine usually has 4 spindles, each spindle absorbs 1 to 3 12-inch silicon wafers, and the bottom of the polishing machine is a large grinding disc with a CMP polishing pad attached to the large disc surface below, and polishing slurry is used for polishing. During the polishing process, the spindle is pressed down and rotates clockwise, while the grinding disc rotates counterclockwise. One operation can process 4 to 12 12-inch silicon wafers.

[0004] Due to the use of multi-chip operation, there is a higher risk of breakage. In addition, the use of multi-chip operation makes it difficult to control the thickness and total thickness deviation (TTV) of the wafer, affecting the quality consistency and production efficiency of the substrate and wafer. Summary of the invention

[0005] The present invention overcomes the problem in the prior art that when a multi-wafer polishing machine is used to polish wafers, the wafer thickness and total thickness deviation are prone to be difficult to control, thereby affecting the consistency of the quality of the substrate and the wafer and reducing the production efficiency. A wafer mirror polishing device is provided, which can respectively realize fine polishing and rough polishing of the wafer through two main shafts, and each main shaft only polishes one wafer at a time. In conjunction with a wafer thickness gauge and a polishing pad sorting disk, the thickness of each wafer can be detected in real time to ensure that the thickness of the wafer meets the production standard, and at the same time, impurities on the grinding head can be removed in real time to keep the thickness of the grinding head consistent, thereby ensuring the quality of the product.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: a wafer mirror polishing device, comprising:

[0007] A wafer mirror polishing device, characterized in that it comprises:

[0008] A load-carrying slide, which is provided with a load-carrying platform that moves along its length direction, and a rotatable wafer vacuum suction cup is provided on the load-carrying platform;

[0009] A rough polishing spindle and a fine polishing spindle are sequentially arranged above the bearing platform along its length direction, and both the rough polishing spindle and the fine polishing spindle move along their own axial directions;

[0010] A wafer thickness gauge and a polishing pad finisher are arranged on the carrier, and the polishing pad finisher includes a brush disk;

[0011] The wafer is placed on the wafer vacuum suction cup, and the carrier table drives the wafer to move to the bottom of the rough polishing spindle and the fine polishing spindle in turn, and the wafer is rough polished and fine polished respectively; during polishing, the wafer thickness gauge detects the thickness of the wafer in real time, and the brush disk rotates to clean the polishing pads at the bottom of the rough polishing spindle and the fine polishing spindle in real time.

[0012] During the polishing process, the wafer moves on the same carrier slide and the same carrier table, so that the wafer surface shape can be more easily controlled. Because different wafer vacuum chucks will have total thickness deviation (TTV) with each other, if it is a high-end requirement (TTV<1um), the same wafer vacuum chuck can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum chuck is set on the carrier table, which can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum chuck can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0013] During the polishing process, a rough polishing pad is first installed at the bottom of the rough polishing spindle, and the rough polishing spindle rotates at a speed of 0~3000 RPM. Taking a 12-inch silicon wafer as an example, the rough polishing of a 12-inch silicon wafer can reduce the surface roughness of the wafer from 45nm to 0.3nm after five minutes of rough polishing. The structure of the fine polishing spindle is similar to that of the rough polishing spindle, except that a fine polishing pad is installed at the bottom of the rough polishing spindle, and fine polishing slurry is used during the polishing process. The surface roughness of a 12-inch silicon wafer can be reduced from 0.3nm to below 0.1nm after five minutes of fine polishing.

[0014] During the wafer polishing process, the contact parts of the wafer and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, thereby improving the wafer polishing efficiency. In addition, during the process of the brush disc cleaning the bottom of the rough polishing spindle and the fine polishing spindle, the contact parts of the brush disc and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, so that the brush disc can achieve a better cleaning effect on the rough polishing spindle and the fine polishing spindle.

[0015] Compared with the traditional large-scale multi-wafer polishing machine, although the fine polishing spindle and the rough polishing spindle in the embodiment of the present invention can only polish one wafer, the efficiency is not reduced. Because the rotation speed of the polishing spindle is proportional to the polishing efficiency, the rough polishing spindle and the fine polishing spindle in the present application can be set to an ultra-high rotation speed, thereby improving the polishing efficiency.

[0016] Preferably, a polishing lock is provided at the bottom of the rough polishing spindle and the fine polishing spindle, a polishing head fixedly connected thereto is provided at the bottom of the polishing lock, and a polishing pad is fixedly provided at the bottom of the polishing head; a slurry ring groove is provided on the side of the polishing head away from the polishing pad, and a plurality of slurry holes are provided through the bottom of the slurry ring groove.

[0017] The interior of the rough polishing spindle and the fine polishing spindle are both provided with pipes connected to the slurry ring groove. The polishing slurry flows into the slurry ring groove through the pipes, and then flows into the polishing pad from the slurry holes. Since the slurry holes are evenly distributed at the bottom of the slurry ring groove, and the rough polishing spindle and the fine polishing spindle rotate during polishing, the slurry can be evenly dispersed at the bottom of the polishing pad, so that the wafer surface can be polished more evenly.

[0018] Preferably, a plurality of first through holes are arranged in the circumferential direction of the polishing lock head, and a plurality of first threaded holes cooperating with the first through holes are arranged on a side of the polishing head close to the polishing lock head, and the bolts are threadedly matched with the first threaded holes after passing through the first through holes.

[0019] The polishing lock head and the polishing head are fixedly connected by bolts, so that the polishing head can be easily replaced. In addition, a suitable polishing head can be selected according to the size of the wafer and the polishing standard and installed under the rough polishing spindle and the fine polishing spindle. The polishing head can be easily replaced and repaired.

[0020] Preferably, the polishing pad is adhered to the bottom of the polishing head.

[0021] The polishing pad is a consumable item and needs to be replaced after a period of use. The polishing pad is installed on the bottom of the polishing head by gluing, so that the polishing pad can be replaced very conveniently.

[0022] Preferably, a first convex ring and a second convex ring are concentrically arranged on the end face of the polishing head close to the polishing lock, the first convex ring is arranged along the edge of the polishing head, and the first convex ring and the second convex ring cooperate to form a slurry ring groove; the first threaded hole is arranged on the first convex ring.

[0023] The first convex ring is convenient for setting a first threaded hole on its upper end surface, so that the first threaded hole can cooperate with the first through hole. At the same time, the first convex ring and the second convex ring cooperate to form a slurry ring groove, so that the slurry can penetrate the polishing pad evenly through the slurry ring groove.

[0024] Preferably, when the rough polishing spindle and the fine polishing spindle are polishing the wafer, the axis centers of the rough polishing spindle and the fine polishing spindle do not coincide with the axis center of the wafer vacuum chuck.

[0025] The above structure allows a part of the polishing pad to polish the wafer, while the other part is in contact with the brush disk, and the brush disk cleans the polishing pad. It should be noted that during the wafer polishing process, the contact parts of the wafer and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, thereby improving the polishing efficiency of the wafer. In addition, during the process of the brush disk cleaning the bottom of the rough polishing spindle and the fine polishing spindle, the contact parts of the brush disk and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, so that the brush disk can have a better cleaning effect on the rough polishing spindle and the fine polishing spindle.

[0026] Preferably, a telescopic sleeve is provided on the bearing slide, and the two ends of the telescopic sleeve are respectively fixedly connected to the two ends of the length direction of the bearing slide; the bearing platform is inserted into the telescopic sleeve; the telescopic sleeve is extended and retracted as the bearing platform moves to prevent the grinding slurry from falling into the bottom of the bearing slide.

[0027] The telescopic sleeve is extended and retracted as the bearing platform moves, preventing the slurry during polishing from falling into the bottom of the bearing platform, thereby protecting the parts in the closed space.

[0028] Preferably, a track is provided on the load-bearing slide along its length direction, and a slider cooperating with the track is provided at the bottom of the load-bearing slide.

[0029] The track cooperates with the slider so that the load-bearing slide can slide stably along the load-bearing slide.

[0030] Preferably, the outer side wall of the polishing lock is provided with a plurality of cleaning devices, the cleaning devices comprising a cleaning rod, on which a cleaning brush is provided; one end of the cleaning rod is rotatably connected to the outer side wall of the polishing lock, a limit seat and an abutment seat are provided on the outer side wall of the polishing lock, the abutment seat and the limit seat are respectively located below and above the rotation position of the cleaning rod, a return spring is abutted between the abutment seat and the cleaning rod, and the return spring pushes the cleaning rod to abut against the limit seat;

[0031] A guide track is arranged on the periphery of the brush plate, and an opening at one end of the guide track gradually increases.

[0032] Although the brush disk can clean the polishing pad, the fine particles generated by grinding the wafer will remain on the brush disk. The impurities and fine particles remaining on the brush disk will affect the cleaning effect of the polishing pad. The brush disk needs to be cleaned after a period of use. Therefore, a cleaning device is provided in this embodiment to clean the brush disk, thereby extending the time for each cleaning of the brush disk, reducing the time spent on cleaning the brush disk, and improving work efficiency.

[0033] The present application also provides a wafer mirror polishing method, comprising the above-mentioned wafer mirror polishing device, and further comprising the following steps:

[0034] S01, the carrier moves to one end of the carrier slide, the wafer is placed on the wafer vacuum chuck, and the carrier moves to below the rough polishing spindle;

[0035] S02, the rough polishing spindle descends to a set position, and the rough polishing spindle and the vacuum chuck rotate to perform rough polishing on the wafer;

[0036] S03, after the rough polishing is completed, the rough polishing spindle moves upward, and the bearing platform moves to the bottom of the fine polishing spindle;

[0037] S04, the fine polishing spindle descends to a set position, and the fine polishing spindle and the vacuum chuck rotate to perform fine polishing on the wafer;

[0038] S05. After the fine polishing is completed, the fine polishing spindle moves upward, the carrier moves to the initial position, the polished wafer is removed, and the above S01 to S04 are repeated.

[0039] Using the above method, the wafer is moved on the same carrier slide and the same carrier table during the polishing process, so that the wafer surface shape can be more easily controlled. Because different wafer vacuum chucks will have total thickness deviation (TTV) with each other, if it is a high-end requirement (TTV<1um), the same wafer vacuum chuck can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum chuck is set on the carrier table, and the wafer vacuum chuck can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum chuck can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0040] During the polishing process, a rough polishing pad is first installed at the bottom of the rough polishing spindle, and the rough polishing spindle rotates at a speed of 0~3000 RPM. Taking a 12-inch silicon wafer as an example, the rough polishing of a 12-inch silicon wafer can reduce the surface roughness of the wafer from 45nm to 0.3nm after five minutes of rough polishing. The structure of the fine polishing spindle is similar to that of the rough polishing spindle, except that a fine polishing pad is installed at the bottom of the rough polishing spindle, and fine polishing slurry is used during the polishing process. The surface roughness of a 12-inch silicon wafer can be reduced from 0.3nm to below 0.1nm after five minutes of fine polishing.

[0041] In addition, during the wafer polishing process, the contact parts of the wafer and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, thereby improving the wafer polishing efficiency. In addition, during the brush disc cleaning the bottom of the rough polishing spindle and the fine polishing spindle, the contact parts of the brush disc and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, so that the brush disc can achieve a better cleaning effect on the rough polishing spindle and the fine polishing spindle.

[0042] Compared with the traditional large multi-wafer polishing machine, although the fine polishing spindle and the rough polishing spindle in this embodiment can only polish one wafer, the efficiency is not reduced. Because the speed of the polishing spindle is proportional to the polishing efficiency, the rough polishing spindle and the fine polishing spindle in this application can be set to an ultra-high speed, thereby improving the polishing efficiency.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) During the polishing process, the wafer moves on the same carrier slide and the same carrier table, making it easier to control the wafer surface shape. Because different wafer vacuum chucks have total thickness deviation (TTV) from each other, if it is a high-end requirement (TTV <1um), the same wafer vacuum chuck can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum chuck is set on the carrier table. The wafer vacuum chuck can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum chuck can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0045] (2) During the wafer polishing process, the contact parts of the wafer and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, thereby improving the polishing efficiency of the wafer. In addition, during the process of the brush disc cleaning the bottom of the rough polishing spindle and the fine polishing spindle, the contact parts of the brush disc and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, so that the brush disc can have a better cleaning effect on the rough polishing spindle and the fine polishing spindle.

[0046] (3) A wafer thickness gauge and a polishing pad finisher are provided. The wafer thickness gauge can detect the thickness and total thickness deviation (TTV) of the wafer in real time, thereby ensuring the quality after processing. The polishing pad finisher can immediately clean the impurities on the polishing pad during the polishing of the wafer by the fine polishing spindle or the rough polishing spindle, ensuring that the thickness of the polishing pad remains consistent, thereby ensuring the quality of the wafer after polishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of the present invention.

[0048] Figure 2 It is a structural schematic diagram of the present invention from another angle.

[0049] Figure 3 It is a schematic structural diagram of the present invention after the telescopic sleeve is removed.

[0050] Figure 4 It is an exploded structural diagram of the rough polishing spindle of the present invention.

[0051] Figure 5It is an exploded structural diagram of the rough polishing spindle from another angle of the present invention.

[0052] Figure 6 It is a schematic diagram of the structure in Example 3 of the present invention.

[0053] Figure 7 This is a front view of Example 3 of the present invention.

[0054] Figure 8 yes Figure 7 A partial enlarged view of the .

[0055] In the figure: 1, load-bearing slide, 11, load-bearing platform, 12, track, 13, slider, 14, buffer butt joint;

[0056] 2. Rough polishing spindle, 21. Polishing lock head, 211. First through hole, 22. Polishing head, 221. Slurry ring groove, 222. Slurry hole, 223. First convex ring, 224. Second convex ring, 225. First threaded hole, 23. Polishing pad;

[0057] 3. Fine polishing of the spindle;

[0058] 4. Wafer thickness gauge, 41. Contact wafer thickness gauge, 42. Non-contact wafer thickness gauge;

[0059] 5. Polishing pad finisher, 51. Brush plate;

[0060] 6. Wafer vacuum chuck;

[0061] 7. Auxiliary slurry pipe, 71. Slurry outlet;

[0062] 8. Telescopic sleeve;

[0063] 9. Cleaning device, 91. Cleaning rod, 92. Cleaning brush, 93. Limiting seat, 94. Abutting seat, 95. Guide rail, 96. Return spring. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0065] Example 1: Reference Figures 1 to 5 As shown, a wafer mirror polishing device comprises:

[0066] A carrying slide 1, on which a carrying platform 11 is arranged to move along its length direction, and on which a rotatable wafer vacuum suction cup 6 is arranged;

[0067] A rough polishing spindle 2 and a fine polishing spindle 3 are sequentially arranged above the carrier 11 along its length direction, and both the rough polishing spindle 2 and the fine polishing spindle 3 move along their own axial directions;

[0068] A wafer thickness gauge 4 and a polishing pad finisher 5 are arranged on the carrier 11, and the polishing pad finisher 5 includes a brush plate 51;

[0069] The wafer is placed on the wafer vacuum suction cup 6, and the carrier 11 drives the wafer to move to the bottom of the rough polishing spindle 2 and the fine polishing spindle 3 in turn, and the wafer is rough polished and fine polished respectively; during polishing, the wafer thickness gauge 4 detects the thickness of the wafer in real time, and the brush disk 51 rotates to clean the polishing pad 23 at the bottom of the rough polishing spindle 2 and the fine polishing spindle in real time.

[0070] In this embodiment, the wafer moves on the same carrier slide 1 and the same carrier platform 11 during the polishing process, so that the wafer surface shape can be more easily controlled. Because different wafer vacuum suction cups 6 have total thickness deviations (TTV) from each other, if it is a high-end requirement (TTV<1um), the same wafer vacuum suction cup 6 can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum suction cup 6 is arranged on the carrier platform 11, and the wafer vacuum suction cup 6 can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum suction cup 6 can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0071] During the polishing process, first, a rough polishing pad 23 is provided at the bottom of the rough polishing spindle 2, and the rough polishing spindle 2 rotates at a speed of 0-3000 RPM. Taking a 12-inch silicon wafer as an example, the roughness of the wafer surface can be reduced from 45nm to 0.3nm after five minutes of rough polishing. The structure of the fine polishing spindle 3 is similar to that of the rough polishing spindle 2, except that a fine polishing pad 23 is installed at the bottom of the rough polishing spindle 2, and a fine polishing slurry is used during the polishing process. The surface roughness of a 12-inch silicon wafer can be reduced from 0.3nm to below 0.1nm after five minutes of fine polishing.

[0072] During the wafer polishing process, the contact parts of the wafer and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, thereby improving the polishing efficiency of the wafer. In addition, during the cleaning process of the rough polishing spindle 2 and the fine polishing spindle 3 by the brush disk 51, the contact parts of the brush disk 51 and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, so that the brush disk 51 can have a better cleaning effect on the rough polishing spindle 2 and the fine polishing spindle 3.

[0073] Compared with the traditional large multi-wafer polishing machine, although the fine polishing spindle 3 and the rough polishing spindle 2 in this embodiment can only polish one wafer, the efficiency is not reduced. Because the speed of the polishing spindle is proportional to the polishing efficiency, the rough polishing spindle 2 and the fine polishing spindle 3 in this application can be set to an ultra-high speed, thereby improving the polishing efficiency.

[0074] In this embodiment, a wafer thickness gauge 4 and a polishing pad finisher 5 are also provided. The wafer thickness gauge 4 can detect the thickness and total thickness deviation (TTV) of the wafer in real time, thereby ensuring the quality after processing. The polishing pad finisher 5 can immediately clean the impurities on the polishing pad 23 during the process of polishing the wafer by the fine polishing spindle 3 or the rough polishing spindle 2, thereby ensuring that the thickness of the polishing pad 23 remains consistent, thereby ensuring the quality of the wafer after polishing.

[0075] Example 2: Reference Figures 1 to 5 As shown, a wafer mirror polishing device includes a carrying slide 1, a rough polishing spindle 2, a fine polishing spindle 3, a wafer thickness gauge 4 and a polishing pad finisher 5.

[0076] The carrying slide 1 is provided with a carrying platform 11 that moves along its length direction, and the carrying platform 11 is provided with a rotatable wafer vacuum suction cup 6;

[0077] A rough polishing spindle 2 and a fine polishing spindle 3 are sequentially arranged above the carrier 11 along its length direction, and the rough polishing spindle 2 and the fine polishing spindle 3 move along their own axial directions;

[0078] A wafer thickness gauge 4 and a polishing pad finisher 5 are arranged on the carrier 11, and the polishing pad finisher 5 includes a brush plate 51; the bottom of the brush plate 51 is connected to a motor, and the brush plate 51 can rotate under the drive of the motor;

[0079] Among them, the wafer is placed on the wafer vacuum suction cup 6, and the carrier platform 11 drives the wafer to move to the bottom of the rough polishing spindle 2 and the fine polishing spindle 3 in turn. The rough polishing spindle 2 and the fine polishing spindle 3 perform rough polishing and fine polishing on the wafer in turn; when polishing the wafer, the wafer thickness gauge 4 detects the thickness of the wafer in real time, and at the same time the brush disk 51 rotates to clean the polishing pad 23 at the bottom of the rough polishing spindle 2 and the fine polishing spindle 3 in real time.

[0080] The structure of the rough polishing spindle 2 is similar to that of the fine polishing spindle 3. Specifically, a polishing lock 21 is provided at the bottom of the rough polishing spindle 2 and the fine polishing spindle 3, and a polishing head 22 is provided at the bottom of the polishing lock 21, and the polishing head 22 is fixedly connected to the polishing lock 21. A polishing pad 23 is fixedly provided at the bottom of the polishing head 22; a slurry annular groove 221 is provided on the side of the polishing head 22 away from the polishing pad 23, and a plurality of slurry holes 222 are provided through the bottom of the slurry annular groove 221, and the slurry holes 222 are evenly distributed at the bottom of the slurry annular groove 221. It should be noted that the structure of the rough polishing spindle 2 is similar to that of the fine polishing spindle 3, except that a rough polishing pad 23 is installed at the bottom of the rough polishing spindle 2, and a rough polishing slurry is used for polishing, while a fine polishing pad 23 is installed at the bottom of the fine polishing spindle 3, and a fine polishing slurry is used for polishing.

[0081] A first convex ring 223 and a second convex ring 224 are concentrically arranged on the end face of the polishing head 22 close to the polishing lock head 21. The first convex ring 223 is arranged along the edge of the polishing head 22. The first convex ring 223 and the second convex ring 224 cooperate to form a slurry annular groove 221. When the polishing head 22 is installed on the polishing lock head 21, the slurry annular groove 221 cooperates with the polishing lock head 21 to form a relatively closed annular groove, so that the polishing slurry can only flow out from the slurry hole 222, thereby preventing the polishing slurry from leaking to other places.

[0082] The rough polishing spindle 2 and the fine polishing spindle 3 are both provided with pipes connected to the slurry ring groove 221. The polishing slurry flows into the slurry ring groove 221 through the pipes, and the polishing slurry then flows into the polishing pad 23 from the slurry holes 222. Since the slurry holes 222 are evenly distributed at the bottom of the slurry ring groove 221, and the rough polishing spindle 2 and the fine polishing spindle 3 rotate during polishing, the slurry can be evenly dispersed at the bottom of the polishing pad 23, so that the wafer surface can be polished more evenly.

[0083] In addition, it should be noted that in this embodiment, when the carrier 11 moves to the fine polishing position, an auxiliary slurry pipe 7 is also provided, and a flat slurry outlet 71 is provided at the outlet of the auxiliary slurry pipe 7. During the wafer polishing process, the slurry flowing out of the auxiliary slurry outlet 71 falls directly on the wafer, ensuring that the slurry can be sufficiently and evenly laid on the surface of the wafer.

[0084] The polishing lock head 21 is provided with a plurality of first through holes 211 in the circumferential direction, and the polishing head 22 is provided with a plurality of first threaded holes 225 matched with the first through holes 211 on one side close to the polishing lock head 21, that is, the first threaded holes 225 are provided on the end surface of the first convex ring 223. The bolts pass through the first through holes 211 and are threadedly matched with the first threaded holes 225.

[0085] The polishing lock head 21 and the polishing head 22 are fixedly connected by bolts, so that the polishing head 22 can be easily replaced. In this way, a suitable polishing head 22 can be selected according to the size of the wafer and the polishing standard and installed under the rough polishing spindle 2 and the fine polishing spindle 3, which has the characteristic of convenient replacement and maintenance of the polishing head 22.

[0086] The polishing pad 23 is glued to the bottom of the polishing head 22. The polishing pad 23 is a consumable item, and the polishing pad 23 needs to be replaced after being used for a period of time. The polishing pad 23 is installed on the bottom of the polishing head 22 by gluing, so that the polishing pad 23 can be replaced very conveniently.

[0087] When the rough polishing spindle 2 and the fine polishing spindle 3 are polishing the wafer, the axis of the rough polishing spindle 2 and the fine polishing spindle 3 do not coincide with the axis of the wafer vacuum suction cup 6. This causes a part of the polishing pad 23 to polish the wafer, while the other part is in contact with the brush disk 51, and the brush disk 51 cleans the polishing pad 23. It should be noted that in the process of polishing the wafer, the contact parts of the wafer and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, thereby improving the polishing efficiency of the wafer. In addition, in the process of the brush disk 51 cleaning the bottom of the rough polishing spindle 2 and the fine polishing spindle 3, the contact parts of the brush disk 51 and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, so that the brush disk 51 can have a better cleaning effect on the rough polishing spindle 2 and the fine polishing spindle 3.

[0088] In one embodiment, two wafer thickness gauges 4 are provided, and the two wafer thickness gauges 4 are respectively a contact wafer thickness gauge 41 and a non-contact wafer thickness gauge 42. The non-contact wafer thickness gauge 42 uses laser to perform real-time detection on the wafer. The two thickness gauges can be used simultaneously or separately, thereby improving the accuracy of wafer thickness measurement.

[0089] In one embodiment, a telescopic sleeve 8 is sleeved on the bearing slide 1. The telescopic sleeve 8 is a sleeve composed of a plurality of folded small units. One side of the sleeve is open, and the opening is matched with the bearing slide 1. The two ends of the telescopic sleeve 8 are respectively fixedly connected with the two ends of the length direction of the bearing slide 1, and the bottom of the telescopic sleeve 8 is slidably set on the bearing platform 11. The telescopic sleeve 8 and the bearing slide 1 form a closed space, and the telescopic sleeve 8 plays a role in shielding the closed space. The bearing platform 11 is penetrated on the telescopic sleeve 8, and the telescopic sleeve 8 is sealed at the position where it is connected to the bearing Tang. The telescopic sleeve 8 is telescoped with the movement of the bearing platform 11 to prevent the slurry during polishing from falling into the bottom of the bearing slide, and to protect the parts in the closed space.

[0090] A track 12 is provided on the load-bearing slide 1 along its length direction, and a slider 13 cooperating with the track 12 is provided at the bottom of the load-bearing slide 11. In this embodiment, two groups of tracks 12 and sliders 13 are provided, and the two groups of sliders 13 cooperate with the tracks 12, so that the load-bearing slide 11 can move more stably. In addition, buffer abutment joints 14 are provided on the inner sides of both ends of the load-bearing slide 1, and when the load-bearing slide 11 moves to the end of the load-bearing slide 1, the buffer abutment joints 14 can play a buffering role on the load-bearing slide 1.

[0091] In this embodiment, the wafer moves on the same carrier slide 1 and the same carrier platform 11 during the polishing process, so that the wafer surface shape can be more easily controlled. Because different wafer vacuum suction cups 6 have total thickness deviations (TTV) from each other, if it is a high-end requirement (TTV<1um), the same wafer vacuum suction cup 6 can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum suction cup 6 is arranged on the carrier platform 11, and the wafer vacuum suction cup 6 can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum suction cup 6 can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0092] During the polishing process, first, a rough polishing pad 23 is provided at the bottom of the rough polishing spindle 2, and the rough polishing spindle 2 rotates at a speed of 0-3000 RPM. Taking a 12-inch silicon wafer as an example, the roughness of the wafer surface can be reduced from 45nm to 0.3nm after five minutes of rough polishing. The structure of the fine polishing spindle 3 is similar to that of the rough polishing spindle 2, except that a fine polishing pad 23 is installed at the bottom of the rough polishing spindle 2, and a fine polishing slurry is used during the polishing process. The surface roughness of a 12-inch silicon wafer can be reduced from 0.3nm to below 0.1nm after five minutes of fine polishing.

[0093] Compared with the traditional large multi-wafer polishing machine, although the fine polishing spindle 3 and the rough polishing spindle 2 in this embodiment can only polish one wafer, the efficiency is not reduced. Because the speed of the polishing spindle is proportional to the polishing efficiency, the rough polishing spindle 2 and the fine polishing spindle 3 in this application can be set to an ultra-high speed, thereby improving the polishing efficiency.

[0094] In this embodiment, a wafer thickness gauge 4 and a polishing pad finisher 5 are also provided. The wafer thickness gauge 4 can detect the thickness and total thickness deviation (TTV) of the wafer in real time, thereby ensuring the quality after processing. The polishing pad finisher 5 can immediately clean the impurities on the polishing pad 23 during the process of polishing the wafer by the fine polishing spindle 3 or the rough polishing spindle 2, thereby ensuring that the thickness of the polishing pad 23 remains consistent, thereby ensuring the quality of the wafer after polishing.

[0095] Example 3: Reference Figures 6 to 8 As shown, the structure of this embodiment is similar to that of the embodiment 2, except that a plurality of cleaning devices 9 are provided on the outer wall of the polishing lock, and the plurality of cleaning devices 9 form a fan-shaped cleaning area; the cleaning device 9 includes a cleaning rod 91, and a cleaning brush 92 facing the bearing platform is provided on the cleaning rod 91. One end of the cleaning rod 91 is rotatably connected to the outer wall of the polishing lock, and a limit seat 93 and an abutment seat 94 are provided on the outer wall of the polishing lock, and the abutment seat 94 and the limit seat 93 are respectively located below and above the rotation position of the cleaning rod 91, and a reset spring 96 is abutted between the abutment seat 94 and the cleaning rod 91, and the reset spring pushes the cleaning rod 91 to abut against the limit seat 93.

[0096] A guide track 95 is arranged at the periphery of the brush plate, and the opening of one end of the guide track 95 gradually increases. A mounting side plate is arranged at the periphery of the brush plate, and the mounting side plate is a cylindrical surface, and the guide track 95 is a through groove arranged in the mounting side plate.

[0097] In Example 2, although the brush disk can clean the polishing pad, the fine particles generated by grinding the wafer will remain on the brush disk. The impurities and fine particles remaining on the brush disk will affect the cleaning effect of the polishing pad. The brush disk needs to be cleaned after a period of use. Therefore, in this embodiment, a cleaning device 9 is provided to clean the brush disk, thereby extending the time for each brush disk cleaning, reducing the time spent on cleaning the brush disk, and improving work efficiency.

[0098] The working principle of this embodiment is as follows: when the rough polishing spindle or the fine polishing spindle is rotating and polishing, the cleaning rod 91 will enter the guide track 95 from the opening of the guide track 95. As the guide track 95 gradually shrinks and approaches the brush disk, the cleaning rod 91 moves along the guide track 95 driven by the rough polishing spindle or the fine polishing spindle. The cleaning rod 91 will overcome the force of the reset spring and approach the brush disk. Then, it will contact the brush disk to clean the brush disk. As the rough polishing spindle or the fine polishing spindle rotates, the cleaning rod 91 disengages from the guide track 95. At the moment of disengagement from the guide track 95, the cleaning rod 91 will rotate upward under the force of the reset spring, and the cleaning rod 91 will abut against the limit seat 93, so that the cleaning rod 91 is lifted upward, does not contact the wafer, and does not affect the polishing of the wafer. It also does not affect the auxiliary slurry pipe in conveying slurry on the wafer.

[0099] In addition, when the cleaning rod 91 hits the stop seat 93, the cleaning rod 91 vibrates, thereby vibrating the fine particles and impurities on the cleaning rod 91 off the cleaning brush 92. And under the centrifugal force of the rough polishing spindle or the fine polishing spindle, the fine particles and impurities on the cleaning rod 91 can also be thrown out, so that the brush plate can be cleaned more cleanly next time.

[0100] Therefore, the brush disc can be cleaned once each time the rough polishing spindle or the fine polishing spindle rotates. Although the cleaning rod 91 can only clean a part of the brush disc each time, the brush disc itself is also rotating, and the rotation frequency of the brush disc is different from that of the rough polishing spindle or the fine polishing spindle. The position of the brush disc is different each time, and the brush disc can be cleaned in all aspects under repeated cleaning.

[0101] In addition, it should be noted that when the rough polishing spindle or the fine polishing spindle stops, it is necessary to control the angle of the rough polishing spindle or the fine polishing spindle each time it stops so that the cleaning rod 91 is located outside the guide rail 95 so as not to affect the movement of the carrier each time.

[0102] Example 4: Reference Figures 1 to 5 As shown, a wafer mirror polishing method includes a wafer mirror polishing device. A wafer mirror polishing device includes a carrying slide 1, a rough polishing spindle 2, a fine polishing spindle 3, a wafer thickness gauge 4 and a polishing pad finisher 5.

[0103] The carrying slide 1 is provided with a carrying platform 11 that moves along its length direction, and the carrying platform 11 is provided with a rotatable wafer vacuum suction cup 6;

[0104] A rough polishing spindle 2 and a fine polishing spindle 3 are sequentially arranged above the carrier 11 along its length direction, and the rough polishing spindle 2 and the fine polishing spindle 3 move along their own axial directions;

[0105] A wafer thickness gauge 4 and a polishing pad finisher 5 are arranged on the carrier 11, and the polishing pad finisher 5 includes a brush plate 51; the bottom of the brush plate 51 is connected to a motor, and the brush plate 51 can rotate under the drive of the motor;

[0106] Among them, the wafer is placed on the wafer vacuum suction cup 6, and the carrier platform 11 drives the wafer to move to the bottom of the rough polishing spindle 2 and the fine polishing spindle 3 in turn. The rough polishing spindle 2 and the fine polishing spindle 3 perform rough polishing and fine polishing on the wafer in turn; when polishing the wafer, the wafer thickness gauge 4 detects the thickness of the wafer in real time, and at the same time the brush disk 51 rotates to clean the polishing pad 23 at the bottom of the rough polishing spindle 2 and the fine polishing spindle 3 in real time.

[0107] The structure of the rough polishing spindle 2 is similar to that of the fine polishing spindle 3. Specifically, a polishing lock 21 is provided at the bottom of the rough polishing spindle 2 and the fine polishing spindle 3, and a polishing head 22 is provided at the bottom of the polishing lock 21, and the polishing head 22 is fixedly connected to the polishing lock 21. A polishing pad 23 is fixedly provided at the bottom of the polishing head 22; a slurry annular groove 221 is provided on the side of the polishing head 22 away from the polishing pad 23, and a plurality of slurry holes 222 are provided through the bottom of the slurry annular groove 221, and the slurry holes 222 are evenly distributed at the bottom of the slurry annular groove 221. It should be noted that the structure of the rough polishing spindle 2 is similar to that of the fine polishing spindle 3, except that a rough polishing pad 23 is installed at the bottom of the rough polishing spindle 2, and a rough polishing slurry is used for polishing, while a fine polishing pad 23 is installed at the bottom of the fine polishing spindle 3, and a fine polishing slurry is used for polishing.

[0108] A first convex ring 223 and a second convex ring 224 are concentrically arranged on the end face of the polishing head 22 close to the polishing lock head 21. The first convex ring 223 is arranged along the edge of the polishing head 22. The first convex ring 223 and the second convex ring 224 cooperate to form a slurry annular groove 221. When the polishing head 22 is installed on the polishing lock head 21, the slurry annular groove 221 cooperates with the polishing lock head 21 to form a relatively closed annular groove, so that the polishing slurry can only flow out from the slurry hole 222, thereby preventing the polishing slurry from leaking to other places.

[0109] The rough polishing spindle 2 and the fine polishing spindle 3 are both provided with pipes connected to the slurry ring groove 221. The polishing slurry flows into the slurry ring groove 221 through the pipes, and the polishing slurry then flows into the polishing pad 23 from the slurry holes 222. Since the slurry holes 222 are evenly distributed at the bottom of the slurry ring groove 221, and the rough polishing spindle 2 and the fine polishing spindle 3 rotate during polishing, the slurry can be evenly dispersed at the bottom of the polishing pad 23, so that the wafer surface can be polished more evenly.

[0110] In addition, it should be noted that in this embodiment, when the carrier 11 moves to the fine polishing position, an auxiliary slurry pipe 7 is also provided, and a flat slurry outlet 71 is provided at the outlet of the auxiliary slurry pipe 7. During the wafer polishing process, the slurry flowing out of the auxiliary slurry outlet 71 falls directly on the wafer, ensuring that the slurry can be sufficiently and evenly laid on the surface of the wafer.

[0111] The polishing lock head 21 is provided with a plurality of first through holes 211 in the circumferential direction, and the polishing head 22 is provided with a plurality of first threaded holes 225 matched with the first through holes 211 on one side close to the polishing lock head 21, that is, the first threaded holes 225 are provided on the end surface of the first convex ring 223. The bolts pass through the first through holes 211 and are threadedly matched with the first threaded holes 225.

[0112] The polishing lock head 21 and the polishing head 22 are fixedly connected by bolts, so that the polishing head 22 can be easily replaced. In this way, a suitable polishing head 22 can be selected according to the size of the wafer and the polishing standard and installed under the rough polishing spindle 2 and the fine polishing spindle 3, which has the characteristic of convenient replacement and maintenance of the polishing head 22.

[0113] The polishing pad 23 is glued to the bottom of the polishing head 22. The polishing pad 23 is a consumable item, and the polishing pad 23 needs to be replaced after being used for a period of time. The polishing pad 23 is installed on the bottom of the polishing head 22 by gluing, so that the polishing pad 23 can be replaced very conveniently.

[0114] When the rough polishing spindle 2 and the fine polishing spindle 3 are polishing the wafer, the axis of the rough polishing spindle 2 and the fine polishing spindle 3 do not coincide with the axis of the wafer vacuum suction cup 6. This causes a part of the polishing pad 23 to polish the wafer, while the other part is in contact with the brush disk 51, and the brush disk 51 cleans the polishing pad 23. It should be noted that in the process of polishing the wafer, the contact parts of the wafer and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, thereby improving the polishing efficiency of the wafer. In addition, in the process of the brush disk 51 cleaning the bottom of the rough polishing spindle 2 and the fine polishing spindle 3, the contact parts of the brush disk 51 and the rough polishing spindle 2 and the fine polishing spindle 3 rotate in opposite directions, so that the brush disk 51 can have a better cleaning effect on the rough polishing spindle 2 and the fine polishing spindle 3.

[0115] In one embodiment, two wafer thickness gauges 4 are provided, and the two wafer thickness gauges 4 are respectively a contact wafer thickness gauge 41 and a non-contact wafer thickness gauge 42. The non-contact wafer thickness gauge 42 uses laser to perform real-time detection on the wafer. The two thickness gauges can be used simultaneously or separately, thereby improving the accuracy of wafer thickness measurement.

[0116] In one embodiment, a telescopic sleeve 8 is sleeved on the bearing slide 1. The telescopic sleeve 8 is a sleeve composed of a plurality of folded small units. One side of the sleeve is open, and the opening is matched with the bearing slide 1. The two ends of the telescopic sleeve 8 are respectively fixedly connected with the two ends of the length direction of the bearing slide 1, and the bottom of the telescopic sleeve 8 is slidably set on the bearing platform 11. The telescopic sleeve 8 and the bearing slide 1 form a closed space, and the telescopic sleeve 8 plays a role in shielding the closed space. The bearing platform 11 is penetrated on the telescopic sleeve 8, and the telescopic sleeve 8 is sealed at the position where it is connected to the bearing Tang. The telescopic sleeve 8 is telescoped with the movement of the bearing platform 11 to prevent the slurry during polishing from falling into the bottom of the bearing slide, and to protect the parts in the closed space.

[0117] A track 12 is provided on the load-bearing slide 1 along its length direction, and a slider 13 cooperating with the track 12 is provided at the bottom of the load-bearing slide 11. In this embodiment, two groups of tracks 12 and sliders 13 are provided, and the two groups of sliders 13 cooperate with the tracks 12, so that the load-bearing slide 11 can move more stably. In addition, buffer abutment joints 14 are provided on the inner sides of both ends of the load-bearing slide 1, and when the load-bearing slide 11 moves to the end of the load-bearing slide 1, the buffer abutment joints 14 can play a buffering role on the load-bearing slide 1.

[0118] The following steps are also included:

[0119] S01, the carrying platform 11 moves to one end of the carrying slide 1 (such as Figure 1 The wafer is placed on the wafer vacuum chuck 6, and the carrier 11 is moved to the bottom of the rough polishing spindle 2;

[0120] S02, the rough polishing spindle 2 descends to a set position, the rough polishing spindle 2 and the vacuum chuck start to rotate, the contact surfaces of the rough polishing spindle 2 and the wafer rotate in opposite directions, and the wafer is rough polished;

[0121] S03, after the rough polishing is completed, the rough polishing spindle 2 moves upward, and the bearing platform 11 moves to the bottom of the fine polishing spindle 3;

[0122] S04, the fine polishing spindle 3 descends to the set position, the fine polishing spindle 3 and the vacuum chuck start to rotate, the contact surface of the rough polishing spindle 2 and the wafer rotates in opposite directions, and the wafer is finely polished;

[0123] S05, after the fine polishing is completed, the fine polishing spindle 3 moves upward, and the bearing platform 11 moves to the initial position of the bearing slide 1 (such as Figure 1 The leftmost end as shown), remove the polished wafer, and repeat S01 to S04 above.

[0124] Using the above method, the wafer is moved on the same carrier slide and the same carrier table during the polishing process, so that the wafer surface shape can be more easily controlled. Because different wafer vacuum chucks will have total thickness deviation (TTV) with each other, if it is a high-end requirement (TTV<1um), the same wafer vacuum chuck can ensure that the wafer is polished at the same position (angle) and conditions, thereby ensuring the quality of wafer polishing; and a wafer vacuum chuck is set on the carrier table, and the wafer vacuum chuck can absorb 1~12 inch substrates and wafers. At the same time, the wafer vacuum chuck can rotate at a speed of 0~300 RPM to ensure that the substrate and wafer are stably fixed during the polishing process.

[0125] During the polishing process, a rough polishing pad is first installed at the bottom of the rough polishing spindle, and the rough polishing spindle rotates at a speed of 0~3000 RPM. Taking a 12-inch silicon wafer as an example, the rough polishing of a 12-inch silicon wafer can reduce the surface roughness of the wafer from 45nm to 0.3nm after five minutes of rough polishing. The structure of the fine polishing spindle is similar to that of the rough polishing spindle, except that a fine polishing pad is installed at the bottom of the rough polishing spindle, and fine polishing slurry is used during the polishing process. The surface roughness of a 12-inch silicon wafer can be reduced from 0.3nm to below 0.1nm after five minutes of fine polishing.

[0126] In addition, during the wafer polishing process, the contact parts of the wafer and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, thereby improving the wafer polishing efficiency. In addition, during the brush disc cleaning the bottom of the rough polishing spindle and the fine polishing spindle, the contact parts of the brush disc and the rough polishing spindle and the fine polishing spindle rotate in opposite directions, so that the brush disc can achieve a better cleaning effect on the rough polishing spindle and the fine polishing spindle.

[0127] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A wafer mirror polishing device, characterized in that: include: A load-carrying slide, which is provided with a load-carrying platform that moves along its length direction, and a rotatable wafer vacuum suction cup is provided on the load-carrying platform; A rough polishing spindle and a fine polishing spindle are sequentially arranged above the bearing platform along its length direction, and both the rough polishing spindle and the fine polishing spindle move along their own axial directions; A wafer thickness gauge and a polishing pad finisher are arranged on the carrier, and the polishing pad finisher includes a brush disk; The wafer is placed on the wafer vacuum chuck, and the carrier table drives the wafer to move to the bottom of the rough polishing spindle and the fine polishing spindle in turn, and the wafer is rough polished and fine polished respectively; during polishing, the wafer thickness gauge detects the thickness of the wafer in real time, and the brush disk rotates to clean the polishing pads at the bottom of the rough polishing spindle and the fine polishing spindle in real time; A polishing lock is provided at the bottom of the rough polishing spindle and the fine polishing spindle, and a plurality of cleaning devices are provided on the outer wall of the polishing lock, the cleaning device includes a cleaning rod, and a cleaning brush is provided on the cleaning rod; one end of the cleaning rod is rotatably connected to the outer wall of the polishing lock, and a limit seat and an abutment seat are provided on the outer wall of the polishing lock, the abutment seat and the limit seat are respectively located below and above the rotation position of the cleaning rod, and a reset spring is abutted between the abutment seat and the cleaning rod, and the reset spring pushes the cleaning rod to abut on the limit seat; a guide track is provided on the periphery of the brush disk, and the opening at one end of the guide track gradually increases.

2. The wafer mirror polishing device according to claim 1 is characterized in that: A polishing head fixedly connected to the polishing lock is arranged at the bottom, and a polishing pad is fixedly arranged at the bottom of the polishing head; a slurry ring groove is arranged on the side of the polishing head away from the polishing pad, and a plurality of slurry holes are arranged through the bottom of the slurry ring groove.

3. The wafer mirror polishing device according to claim 2 is characterized in that: The polishing lock head is provided with a plurality of first through holes in the circumferential direction, and a plurality of first threaded holes matching with the first through holes are provided on one side of the polishing head close to the polishing lock head. The bolts are threadably matched with the first threaded holes after passing through the first through holes.

4. The wafer mirror polishing device according to claim 2, characterized in that: The polishing pad is glued to the bottom of the polishing head.

5. The wafer mirror polishing device according to claim 3 is characterized in that: A first convex ring and a second convex ring are concentrically arranged on the end surface of the polishing head close to the polishing lock head. The first convex ring is arranged along the edge of the polishing head. The first convex ring and the second convex ring cooperate to form a slurry ring groove; the first threaded hole is arranged on the first convex ring.

6. The wafer mirror polishing device according to any one of claims 1 to 4, characterized in that: When the rough polishing spindle and the fine polishing spindle are polishing the wafer, the axis center of the rough polishing spindle and the fine polishing spindle does not coincide with the axis center of the wafer vacuum chuck.

7. The wafer mirror polishing device according to any one of claims 1 to 5, characterized in that: A telescopic sleeve is provided on the bearing slide, and the two ends of the telescopic sleeve are respectively fixedly connected to the two ends of the bearing slide in the length direction; the bearing platform is inserted into the telescopic sleeve; the telescopic sleeve is extended and retracted as the bearing platform moves to prevent the grinding slurry from falling into the bottom of the bearing slide.

8. The wafer mirror polishing device according to claim 7, characterized in that: A track is arranged on the bearing slide along the length direction thereof, and a sliding block matched with the track is arranged at the bottom of the bearing slide.

9. A wafer mirror polishing method, characterized in that: The wafer mirror polishing device according to any one of claims 1 to 8 further comprises the following steps: S01, the carrier moves to one end of the carrier slide, the wafer is placed on the wafer vacuum chuck, and the carrier moves to below the rough polishing spindle; S02, the rough polishing spindle descends to a set position, and the rough polishing spindle and the vacuum chuck rotate to perform rough polishing on the wafer; S03, after the rough polishing is completed, the rough polishing spindle moves upward, and the bearing platform moves to the bottom of the fine polishing spindle; S04, the fine polishing spindle descends to a set position, and the fine polishing spindle and the vacuum chuck rotate to perform fine polishing on the wafer; S05. After the fine polishing is completed, the fine polishing spindle moves upward, the carrier moves to the initial position, the polished wafer is removed, and the above S01 to S04 are repeated.

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