Top grinding structure of a wafer grinding machine and the wafer grinding machine

Abstract

The present application relates to a top grinding structure of a wafer grinding machine and a wafer grinding machine, and relates to the technical field of wafer grinding machines. The top grinding structure of the wafer grinding machine includes a mounting base and a plurality of grinding components vertically slidably connected to the mounting base. An internal pressure component is installed in the grinding component, and the internal pressure component is used to apply pressure to the grinding disc, so that the pressure P received by each point of the grinding disc decreases as the distance r from the center point increases. A wafer grinding machine includes: a support structure, a top grinding structure, and a bottom drive structure. The present application has the effect of enhancing the grinding effect.

Description

Technical Field

[0001] The present application relates to a wafer grinding machine, and more particularly to a top grinding structure of a wafer grinding machine and a wafer grinding machine. Background Art

[0002] In the field of semiconductor manufacturing, the processing precision of wafers has a crucial impact on the performance and yield of chips. Wafer grinding is a key link in the wafer processing process, and its purpose is to remove the excess material on the wafer surface through the relative movement between the grinding disc and the wafer to meet the predetermined thickness and flatness requirements.

[0003] Traditional wafer grinding equipment usually adopts a rotary grinding disc structure. In this structure, the grinding disc is driven by a motor to rotate at a high speed around its central axis, and the wafer is fixed on the carrier table and kept in pressure contact with the grinding disc. During the grinding process, the relative movement between the grinding disc and the wafer generates a grinding effect, and the material on the wafer surface is gradually removed.

[0004] However, during the rotation of the grinding disc, the linear velocity of the edge part is much greater than that of the central part. According to the principles of physics, the greater the linear velocity, the longer the distance traveled by an object in the same time, and the stronger its grinding effect on the wafer surface. Therefore, during the grinding process, the grinding effect of the edge area of the grinding disc on the wafer is significantly stronger than that of the central area, which leads to unevenness during the grinding of the wafer. Summary of the Invention

[0005] In order to improve the uniformity of wafer grinding, the purpose of the present application is to provide a top grinding structure of a wafer grinding machine and a wafer grinding machine.

[0006] In a first aspect, a top grinding structure of a wafer grinding machine provided by the present application adopts the following technical solution:

[0007] A top grinding structure of a wafer grinding machine includes a mounting base and a plurality of grinding components vertically slidably connected to the mounting base. The mounting base drives the grinding components to move vertically through a first cylinder. The grinding component includes a slider, a rotating shaft rotatably connected to the slider, a driving motor for driving the rotating shaft to rotate, and a disc seat connected to the lower end of the rotating shaft. A grinding disc is fixedly connected to the bottom of the disc seat;

[0008] An internal pressure component is installed in the grinding component. The internal pressure component is used to apply pressure to the grinding disc so that the pressure P received by each point of the grinding disc decreases as the distance r from the center point increases.

[0009] Through the above technical solution, the internal pressure component makes the pressure P received by each point of the grinding disc decrease as the distance r from the center point increases, thereby reducing the grinding intensity of the edge area of the grinding disc on the wafer and increasing the grinding intensity of the central area of the grinding disc on the wafer. This effectively compensates for the problem of uneven grinding amount caused by the difference in linear velocity at different positions during the grinding process of the grinding disc, making the grinding effect of the grinding disc on the wafer more uniform throughout the working area, and significantly improving the flatness and smoothness of the wafer surface.

[0010] Furthermore, the internal pressure component is used to apply pressure to the grinding disc, so that the pressure P received by each point of the grinding disc satisfies the following conditions:

[0011]

[0012] Where: F is the total pressure applied by the internal pressure component to the grinding disc;

[0013] R is the maximum diameter of the grinding disc;

[0014] r is the distance from the center point of the grinding disc.

[0015] Through the above technical solution, it further compensates for the problem of uneven grinding amount caused by the difference in linear velocity at different positions during the grinding process of the grinding disc.

[0016] Furthermore, the internal pressure component includes a central cylinder and multiple distributed cylinders. The central cylinder is coaxially arranged with the grinding disc, and the distributed cylinders are circumferentially and evenly distributed around the center of the grinding disc. The internal pressure component also includes a connecting plate, the grinding disc is bonded to the connecting plate, the movable ends of the central cylinder and the distributed cylinders are both fixedly connected to the connecting plate, and multiple groups of distributed cylinders are provided. Each group of distributed cylinders has multiple distributed cylinders.

[0017] Through the above technical solution, multiple groups of distributed cylinders are circumferentially and evenly distributed around the center of the grinding disc, and are connected to different annular stress areas of the connecting plate. Moreover, the number of each group of distributed cylinders is specifically set according to the inner and outer diameters of the annular stress area. This layout method can more accurately adjust the stress conditions of different areas of the grinding disc, further optimize the pressure distribution curve, ensure a stable and uniform grinding effect under various working conditions, meet the grinding requirements of wafers of different sizes and materials, and enhance the versatility and adaptability of the wafer grinding machine.

[0018] Further, the connecting disk includes a stress-bearing area and a connecting area. The stress-bearing area includes a center stress-bearing area located at the center of the connecting disk and a plurality of annular stress-bearing areas coaxially arranged with the center stress-bearing area. The connecting area is located between adjacent annular stress-bearing areas. An annular deformation groove is provided at the junction of the stress-bearing area and the connecting area of the connecting disk. The annular deformation groove is coaxially arranged with the connecting disk. A plurality of radial deformation grooves are provided in the connecting area of the connecting disk. The radial deformation grooves extend along the radial direction of the connecting disk. Both ends of the radial deformation groove are respectively connected to an annular deformation groove. The movable end of the central cylinder is connected to the center stress-bearing area of the connecting disk, and the distributed cylinders are connected to the annular stress-bearing areas of the connecting disk. One group of distributed cylinders corresponds to one annular stress-bearing area.

[0019] Through the above technical solution, the deformation ability of the connecting disk is improved through the deformation grooves, which helps the connecting disk to bend moderately due to different strengths, so as to apply a more appropriate force to the grinding disk and reduce the influence between different cylinders.

[0020] Further, the number of cylinders in each group of distributed cylinders meets the following requirements:

[0021]

[0022] Wherein: is the number of cylinders in the innermost group of distributed cylinders;

[0023] is the number of cylinders in the 2nd group of distributed cylinders starting from the center of the connecting disk;

[0024] is the number of cylinders in the th group of distributed cylinders starting from the center of the connecting disk;

[0025] is the outer diameter of the innermost annular stress-bearing area;

[0026] is the inner diameter of the innermost annular stress-bearing area;

[0027] is the outer diameter of the 2nd annular stress-bearing area starting from the center of the connecting disk;

[0028] is the inner diameter of the 2nd annular stress-bearing area starting from the center of the connecting disk;

[0029] is the outer diameter of the th annular stress-bearing area starting from the center of the connecting disk;

[0030] is the inner diameter of the th annular stress-bearing area starting from the center of the connecting disk.

[0031] Furthermore, the central cylinder includes a cylinder block, a lower end cover fixedly connected to the cylinder block, a piston ring slidably connected to the cylinder block, and a support disk fixedly connected to the piston ring. The cylinder block is provided with an annular cavity for accommodating the piston ring. The edge of the piston ring is provided with an annular edge. The lower end cover is annular and has a contact portion provided on its inner circle. The contact portion extends into the cavity for abutting against the edge to limit the stroke of the piston ring. The disk seat is provided with a central hole, and the cylinder block is placed in the central hole and fixedly connected to the disk seat.

[0032] Furthermore, the cylinder block is provided with a first air passage. One end of the first air passage communicates with the top end of the annular cavity, and the other end penetrates upward through the cylinder block to communicate with the central hole. The rotating shaft is hollowly arranged and its lower end communicates with the central hole. The upper end of the rotating shaft is connected to a trachea through a rotary joint.

[0033] Furthermore, the disk seat is provided with distribution holes for installing distribution cylinders. The distribution cylinders include guide sleeves arranged in the distribution holes and fixedly connected to the disk seat, piston sheets slidably connected in the distribution holes, and guide rods fixedly connected to the piston sheets. The side wall of the piston sheet fits against the inner wall of the distribution hole, and the piston sheet divides the distribution hole into two independent spaces. One end of the guide rod is fixedly connected to the piston sheet, and the other end is fixedly connected to the connecting disk.

[0034] Furthermore, the disk seat is provided with a second air passage, and the second air passage communicates with the distribution holes.

[0035] In a second aspect, a wafer grinding machine provided by the present application adopts the following technical solution:

[0036] A wafer grinding machine, comprising:

[0037] A support structure for supporting a jig and driving the jig to rotate;

[0038] A top grinding structure of a wafer grinding machine as described in any one of the foregoing, located above the support structure, for grinding a wafer;

[0039] A bottom driving structure for driving the support structure to rotate.

[0040] In summary, the present application includes at least one of the following beneficial technical effects:

[0041] 1. The unique design of the internal pressure component enables the pressure P(r) received by each point on the grinding disc to decrease as the distance r from the center point increases. This pressure distribution pattern can effectively compensate for the uneven grinding amount caused by the difference in linear velocity at different positions during the grinding process of the grinding disc. In the traditional grinding process, due to the linear velocity at the edge of the grinding disc being much greater than that at the center position, it often causes excessive grinding at the edge and insufficient grinding at the center. In this technology, by precisely controlling the pressure distribution, the grinding effect of the grinding disc on the wafer in the entire working area is more uniform, significantly improving the flatness and smoothness of the wafer surface;

[0042] 2. Multiple groups of distributed cylinders are evenly distributed circumferentially with the center of the grinding disc as the center and are connected to different annular stress areas of the connecting disc. Moreover, the number of cylinders in each group of distributed cylinders is specifically set according to the inner and outer diameters of the annular stress area. This layout method can more accurately adjust the stress conditions in different areas of the grinding disc, further optimize the pressure distribution curve, ensure a stable and uniform grinding effect under various working conditions, meet the grinding requirements of wafers of different sizes and materials, and enhance the versatility and adaptability of the wafer grinding machine. Brief Description of the Drawings

[0043] Figure 1 is the overall structural schematic diagram of the embodiment of the present application;

[0044] Figure 2 is the axonometric view of the grinding component used in the embodiment of the present application;

[0045] Figure 3 is the cross-sectional view of the internal structure of the grinding component used in the embodiment of the present application;

[0046] Figure 4 is the structural schematic diagram of the distribution of the central cylinder and the distributed cylinders used in the embodiment of the present application;

[0047] Figure 5 is Figure 3 the partial enlarged schematic diagram of part A in;

[0048] Figure 6 is Figure 3 the partial enlarged schematic diagram of part B in;

[0049] In the figure, 100 is the support structure; 200 is the top grinding structure; 210 is the mounting base; 220 is the grinding assembly; 221 is the slider; 222 is the rotating shaft; 223 is the driving motor; 224 is the disc base; 225 is the grinding disc; 226 is the first cylinder; 230 is the internal pressure assembly; 231 is the central cylinder, including cylinder block 2311, lower end cover 2312, piston ring 2313, support disc 2314, contact part 2315, and edge 2316; 232 is the distribution cylinder, including guide sleeve 2321, piston piece 2322, and guide rod 2323; 233 is the connecting disc; 235 is the central force-bearing area; 236 is the annular force-bearing area; 237 is the connecting area; 238 is the annular deformation groove; 239 is the radial deformation groove; 300 is the bottom driving structure; 401 is the first air passage; 402 is the second air passage. Detailed implementation mode

[0050] The following will further elaborate on this application in conjunction with the attached Figure 1 - attached Figure 6 , and make a more detailed description of this application.

[0051] This embodiment discloses a wafer grinding machine, referring to Figure 1 , including:

[0052] The support structure 100, whose main function is to support the fixture, and the fixture is used to install and fix the wafer;

[0053] The top grinding structure 200, located above the support structure 100, is used for grinding the wafer;

[0054] The bottom driving structure 300 provides rotational power for the support structure 100, ensuring that the support structure 100 and the fixture can rotate stably at a set speed and direction, and cooperating with the top grinding structure 200 to complete the grinding process of the wafer.

[0055] Driven by the bottom driving structure 300, the fixture rotates, enabling the wafer placed on the fixture to perform circular motion, so that the top grinding structure 200 can perform a comprehensive grinding operation on it.

[0056] Referring to Figure 1 , the top grinding structure 200 includes a mounting base 210 and a plurality of grinding assemblies 220 vertically slidably connected to the mounting base 210. The mounting base 210 is rotatably connected to the frame. A plurality of first cylinders 226 are installed on the mounting base 210, and the first cylinders 226 are used to drive the grinding assemblies 220 to move vertically.

[0057] Referring to Figure 1 and Figure 2, the grinding assembly 220 includes a slider 221, a rotating shaft 222 rotatably connected to the slider 221, a driving motor 223 for driving the rotation of the rotating shaft 222, and a disc seat 224 connected to the lower end of the rotating shaft 222. A grinding disc 225 is fixedly connected to the bottom of the disc seat 224. The slider 221 is installed on the mounting seat 210 through a slide rail, and the movable end of the first cylinder 226 is fixedly connected to the slider 221, and the up-and-down sliding of the slider 221 is realized by the drive of the first cylinder 226. A grinding disc 225 is installed at the lower end of the disc seat 224. When the first cylinder 226 works, it drives the slider 221 to move downward, so that the grinding disc 225 abuts against the wafer, and then the driving motor 223 drives the disc seat 224 to rotate through the rotating shaft 222, and the rotation of the disc seat 224 drives the grinding disc 225 to rotate, realizing the grinding of the wafer.

[0058] During the rotation of the grinding disc 225, the linear velocity of its edge part is much greater than that of the central part, and its grinding effect on the wafer surface is also stronger. Therefore, during the grinding process, the grinding effect of the edge area of the grinding disc 225 on the wafer is significantly stronger than that of the central area, which leads to unevenness of the wafer during the grinding process.

[0059] Refer to Figure 3 , to solve the above technical problems, an internal pressure assembly 230 is installed in the grinding assembly 220. The internal pressure assembly 230 is used to apply pressure to the grinding disc 225, so that the pressure P(r) received by each point of the grinding disc 225 decreases as the distance r from the center point increases. More specifically, the internal pressure assembly 230 is used to apply pressure to the grinding disc 225, so that the pressure P(r) received by each point of the grinding disc 225 satisfies the following conditions:

[0060]

[0061] Where: F is the total pressure applied by the internal pressure assembly 230 to the grinding disc 225;

[0062] R is the maximum diameter of the grinding disc 225;

[0063] r is the distance from the center point of the grinding disc 225.

[0064] Refer to Figure 3 and Figure 4 , to achieve the above conditions, the internal pressure assembly 230 includes a central cylinder 231 and a plurality of distribution cylinders 232. Among them, the central cylinder 231 is installed at the center of the disc seat 224 and is coaxially arranged with the grinding disc 225. The distribution cylinders 232 are circumferentially and uniformly distributed with the center of the grinding disc 225 as the center. There are multiple groups of distribution cylinders 232, and the distribution cylinders 232 distributed on the same concentric circle are one group. Each group of distribution cylinders 232 has multiple distribution cylinders 232 and is uniformly distributed with the center of the disc seat 224.

[0065] The internal pressure assembly 230 further includes a connecting plate 233. The grinding disc 225 is bonded to the lower end of the connecting plate 233. The movable ends of the central cylinder 231 and the distribution cylinder 232 are both fixedly connected to the connecting plate 233. The connecting plate 233 includes a stress area and a connecting area 237.

[0066] Referring to Figure 4 , the stress area includes a central stress area 235 located at the center of the connecting plate 233 and a plurality of annular stress areas 236 coaxially arranged with the central stress area 235. An annular connecting area 237 is provided between adjacent annular stress areas 236. An annular deformation groove 238 is provided at the junction of the stress area and the connecting area 237 of the connecting plate 233, and the annular deformation groove 238 is coaxially arranged with the connecting plate 233. A plurality of radial deformation grooves 239 are provided in the connecting area 237 of the connecting plate 233. The radial deformation grooves 239 extend along the radial direction of the connecting plate 233, and both ends of the radial deformation grooves 239 are respectively connected to an annular deformation groove 238. The movable end of the central cylinder 231 is connected to the central stress area of the connecting plate 233, and the distribution cylinder 232 is connected to the annular stress area 236 of the connecting plate 233. One group of distribution cylinders 232 corresponds to one annular stress area 236.

[0067] In order to make the pressure P(r) received by each point of the grinding disc 225 meet the above conditions, the pressure applied by each distribution cylinder 232 is the same, and the number of each group of distribution cylinders 232 meets the following requirements:

[0068]

[0069] Where: is the number of cylinders of the innermost group of distribution cylinders 232;

[0070] is the number of cylinders of the 2nd group of distribution cylinders 232 starting from the center of the connecting plate 233;

[0071] is the number of cylinders of the th group of distribution cylinders 232 starting from the center of the connecting plate 233;

[0072] is the outer diameter of the innermost annular stress area 236;

[0073] is the inner diameter of the innermost annular stress area 236;

[0074] is the outer diameter of the 2nd annular stress area 236 starting from the center of the connecting plate 233;

[0075] is the inner diameter of the 2nd annular stress area 236 starting from the center of the connecting plate 233;

[0076] is the outer diameter of the th annular stress area 236 starting from the center of the connection disk 233;

[0077] is the inner diameter of the th annular stress area 236 starting from the center of the connection disk 233.

[0078] Referring to Figure 4 , taking an 8-inch wafer as an example, four wafers are ground simultaneously. F is 125.6 Kg, and the R of the grinding disk is 30 cm. Two groups of distribution cylinders 232 are arranged from the inside to the outside. 40 , , , ; then . Seven are arranged in the first group and eleven are arranged in the second group.

[0079] Referring to Figure 5 , the disk base 224 is provided with a central hole for installing the central cylinder 231.

[0080] The central cylinder 231 includes a cylinder block 2311, a lower end cover 2312, a piston ring 2313 and a support disk 2314. The cylinder block 2311 is placed in the central hole and fixedly connected to the disk base 224. The lower end cover 2312 is fixedly connected to the cylinder block 2311. The cylinder block 2311 is provided with an annular cavity for accommodating the piston ring 2313, and the piston ring 2313 is slidably connected in the cylinder block 2311. An annular edge 2316 is integrally formed at the edge of the piston ring 2313. The lower end cover 2312 is annular and an annular abutting portion 2315 is provided on the inner circle, and the abutting portion 2315 extends into the cavity for abutting against the edge 2316 to limit the stroke of the piston ring 2313.

[0081] The cylinder block 2311 is provided with a first air passage 401. One end of the first air passage 401 is communicated with the top end of the annular cavity, and the other end penetrates upward through the cylinder block 2311 and is communicated with the central hole. The rotating shaft 222 is hollow and the lower end is communicated with the central hole. The upper end of the rotating shaft 222 is communicated with the air pipe through a rotary joint.

[0082] Referring to Figure 6 , the disk base 224 is provided with distribution holes for installing the distribution cylinders 232 for installing the distribution cylinders 232.

[0083] The distribution cylinder 232 includes a guide sleeve 2321 disposed in the distribution hole and fixedly connected to the disk base 224, a piston piece 2322 slidably connected in the distribution hole, and a guide rod 2323 fixedly connected to the piston piece 2322. The side wall of the piston piece 2322 fits against the inner wall of the distribution hole, and the piston piece 2322 divides the distribution hole into two independent spaces. One end of the guide rod 2323 is fixedly connected to the piston piece 2322, and the other end is fixedly connected to the connection disk 233; the disk base 224 is provided with a second air passage 402, and the second air passage 402 communicates with the distribution hole.

[0084] The implementation principle of the embodiment of this application is as follows: The unique design of the internal pressure assembly 230 enables the pressure P(r) received by each point of the grinding disk 225 to decrease as the distance r from the center point increases. This pressure distribution mode can effectively compensate for the problem of uneven grinding amount caused by the difference in linear velocity at different positions during the grinding process of the grinding disk 225. In the traditional grinding process, since the linear velocity at the edge of the grinding disk 225 is much greater than that at the center position, it often causes excessive grinding at the edge and insufficient grinding at the center. In this technology, by precisely controlling the pressure distribution, the grinding effect of the grinding disk 225 on the wafer in the entire working area is more uniform, significantly improving the flatness and smoothness of the wafer surface.

Claims

1. A top grinding structure of a wafer grinder, characterized in that: The invention comprises a mounting seat (210), and a plurality of grinding assemblies (220) vertically slidably connected to the mounting seat (210); the mounting seat (210) drives the grinding assemblies (220) to move vertically via a first cylinder (226); the grinding assemblies (220) comprise a slider (221), a rotating shaft (222) rotatably connected to the slider (221), a driving motor (223) driving the rotating shaft (222) to rotate, and a disc seat (224) connected to the lower end of the rotating shaft (222); a grinding disc (225) is fixedly connected to the bottom of the disc seat (224); An internal pressure assembly (230) is installed in the grinding assembly (220), and the internal pressure assembly (230) is used to apply pressure to the grinding disc (225), so that the pressure P (r) exerted on each point of the grinding disc (225) decreases as the distance r from the center point increases; The internal pressure component (230) is used to apply pressure to the grinding disc (225) so that the pressure P (r) applied to each point of the grinding disc (225) satisfies the following conditions: ； Wherein: F is the total pressure applied by the internal pressure assembly (230) to the grinding disc (225); R is the maximum diameter of the grinding disc (225); r is the distance from the center point of the grinding disc (225); The internal pressure component (230) comprises a central cylinder (231) and a plurality of distribution cylinders (232), the central cylinder (231) being coaxially arranged with the grinding disc (225), and the distribution cylinders (232) being evenly distributed in the circumferential direction with the grinding disc (225) as the center. The internal pressure component (230) further comprises a connecting disc (233), the grinding disc (225) being bonded to the connecting disc (233), the movable ends of the central cylinder (231) and the distribution cylinders (232) being fixedly connected to the connecting disc (233), and the distribution cylinders (232) being arranged in a plurality of groups, and each group of distribution cylinders (232) having a plurality of distribution cylinders (232); The connecting disk (233) comprises a force-bearing area and a connecting area (237), wherein the force-bearing area comprises a central force-bearing area (235) located at the center of the connecting disk (233) and a plurality of annular force-bearing areas (236) coaxially arranged with the central force-bearing area (235), wherein the connecting area (237) is located between adjacent annular force-bearing areas (236), and the connecting disk (233) is provided with an annular deformation groove (238) at the junction of the force-bearing area and the connecting area (237), wherein the annular deformation groove (238) is coaxially arranged with the connecting disk (233), and the connecting disk (233) is provided with a plurality of radial deformation grooves (239) in the connection area (237), the radial deformation grooves (239) extending along the radial direction of the connection disk (233), the two ends of the radial deformation grooves (239) are respectively connected to an annular deformation groove (238), the movable end of the central cylinder (231) is connected to the center force area (235) of the connection disk (233), the distribution cylinder (232) is connected to the annular force area (236) of the connection disk (233), and a group of distribution cylinders (232) corresponds to one annular force area (236).

2. The top grinding structure of a wafer grinder according to claim 1, characterized in that: The number of each group of distributed cylinders (232) meets the following requirements: ； in: is the number of cylinders of the innermost group of distribution cylinders (232); is the number of cylinders close to the second group of distribution cylinders (232) starting from the center of the connection plate (233); is the number of cylinders close to the xth group of distribution cylinders (232) starting from the center of the connection plate (233); is the outer diameter of the innermost annular force-bearing area (236); is the inner diameter of the innermost annular force-bearing area (236); The outer diameter of the second annular force-bearing area (236) starting from the center of the connecting plate (233); The inner diameter of the second annular force-bearing area (236) starting from the center of the connecting plate (233); is the outer diameter of the xth annular force-bearing area (236) starting from the center of the connecting plate (233); It is the inner diameter of the xth annular force-bearing area (236) starting from the center of the connecting plate (233).

3. The top grinding structure of a wafer grinder according to claim 1, characterized in that: The central cylinder (231) comprises a cylinder body (2311), a lower end cover (2312) fixedly connected to the cylinder body (2311), a piston ring (2313) slidably connected to the cylinder body (2311), and a support plate (2314) fixedly connected to the piston ring (2313); the cylinder body (2311) is provided with an annular cavity for accommodating the piston ring (2313); the edge of the piston ring (2313) is provided with an annular edge (2316); the lower end cover (2312) is annular and has an inner ring provided with a contact portion (2315); the contact portion (2315) extends into the cavity for contacting with the edge (2316) to limit the stroke of the piston ring (2313); the disc seat (224) is provided with a central hole; the cylinder body (2311) is placed in the central hole and is fixedly connected to the disc seat (224).

4. The top grinding structure of a wafer grinder according to claim 3, characterized in that: The cylinder body (2311) is provided with a first air channel (401), one end of the first air channel (401) is connected to the top of the annular cavity, and the other end of the first air channel (401) passes through the cylinder body (2311) upwards and is connected to the center hole. The rotating shaft (222) is hollow and the lower end is connected to the center hole. The upper end of the rotating shaft (222) is connected to the air pipe via a rotating joint.

5. The top grinding structure of a wafer grinder according to claim 4, characterized in that: The disc seat (224) is provided with a distribution hole for installing a distribution cylinder (232); the distribution cylinder (232) comprises a guide sleeve (2321) arranged in the distribution hole and fixedly connected to the disc seat (224), a piston plate (2322) slidably connected to the distribution hole, and a guide rod (2323) fixedly connected to the piston plate (2322); a side wall of the piston plate (2322) is fitted with an inner wall of the distribution hole, and the piston plate (2322) divides the distribution hole into two independent spaces; one end of the guide rod (2323) is fixedly connected to the piston plate (2322), and the other end is fixedly connected to the connecting disc (233).

6. The top grinding structure of a wafer grinder according to claim 5, characterized in that: The disc seat (224) is provided with a second air channel (402), and the second air channel (402) is connected to the distribution hole.

7. A wafer grinding machine, characterized in that: include: A support structure (100), used for supporting the jig and driving the jig to rotate; A top grinding structure of a wafer grinder as claimed in any one of claims 1 to 5, located above the support structure (100), and used for grinding wafers; The bottom driving structure (300) is used to drive the supporting structure (100) to rotate.

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