Wafer grinding assembly, wafer thinning device and thinning method

Abstract

The application provides a wafer grinding assembly, a wafer thinning device and a thinning method, and belongs to the technical field of wafer processing equipment. The grinding assembly comprises a support body and a bearing core rotatably arranged on the support body. A rotating spindle is connected above the bearing core. A grinding wheel is connected below the bearing core. The rotating spindle is used to drive the bearing core and the grinding wheel to rotate synchronously to polish the wafer. The rotating spindle has a liquid passage hole penetrating through the middle part in the axial direction to pass liquid. An isolation sleeve is connected to the lower end of the rotating spindle and communicates with the liquid passage hole to pass the liquid flow in the liquid passage hole. The isolation sleeve penetrates through the bearing core. A heat insulation gas cavity is formed between the isolation sleeve and the bearing core. The heat insulation gas cavity is used to pass the gas flow to insulate the bearing core. The application utilizes the poor heat conductivity of the gas in the heat insulation gas cavity to avoid the direct contact between the liquid flow and the bearing core, so that the stability of the bearing core is not affected by the deformation of the bearing core caused by the temperature change.

Description

Technical Field

[0001] This application belongs to the field of wafer processing equipment technology, and more specifically, relates to a wafer grinding assembly, a wafer thinning device, and a thinning method. Background Technology

[0002] Before wafer packaging, a thinning device is needed to grind and thin the back side of the wafer. This thinning device uses an air-static electric spindle to fix a grinding wheel, which thins the wafer through relative rotational friction with the wafer. In practical use, because the grinding wheel needs to maintain a speed of over 2000 rpm, the gas friction between the air bearing of the air-static electric spindle and the rotating spindle, as well as the heat generated by the motor, causes the air bearing temperature to rise. This leads to air bearing deformation, decreased stability of the air-static electric spindle, and reduced positional accuracy of the grinding wheel.

[0003] In the existing technology, water is intermittently passed through the center of the rotating spindle to reduce the temperature. However, since the water passed through the center will come into direct contact with the air bearing and undergo heat exchange, the bearing structure will change, causing the thickness of the air film in different areas of the bearing to vary. This affects the installation position of the grinding wheel relative to the rotating spindle, and thus affects the grinding accuracy of the wafer. Summary of the Invention

[0004] In view of the above problems, this application provides a wafer grinding assembly, a wafer thinning device and a thinning method, thereby solving or at least alleviating one or more of the above problems and other problems existing in the prior art.

[0005] A first aspect of this application provides a wafer grinding assembly, comprising:

[0006] A support body, on which a bearing core is rotatably mounted, and an outer sleeve is provided on the support body;

[0007] A rotating spindle is connected above the bearing core and located inside the outer sleeve. A grinding wheel is connected below the bearing core. The rotating spindle is used to drive the bearing core and the grinding wheel to rotate synchronously to polish the wafer. A liquid passage hole is provided in the middle of the rotating spindle for axial penetration of liquid.

[0008] An isolation sleeve is connected to the lower end of the rotating spindle and communicates with the liquid passage hole for the liquid flow in the liquid passage hole to pass through. The isolation sleeve is disposed through the bearing core, and a heat insulation air cavity is formed between the isolation sleeve and the bearing core. The heat insulation air cavity is used to introduce airflow to insulate the bearing core.

[0009] In one embodiment, the grinding wheel has an exhaust port communicating with the heat insulation chamber. The exhaust port penetrates the peripheral wall of the grinding wheel to discharge gas from the heat insulation chamber and cool the grinding wheel.

[0010] In one embodiment, the outer wall of the isolation sleeve is provided with threads, which can guide the gas in the heat insulation cavity to be discharged when the isolation sleeve rotates.

[0011] In one embodiment, the grinding wheel has a drain hole communicating with the isolation sleeve, the drain hole penetrating the peripheral wall of the grinding wheel to drain the liquid inside the isolation sleeve and cool the grinding wheel and the wafer.

[0012] In one embodiment, the lower end of the isolation sleeve is provided with a contraction cone extending into the grinding wheel, the contraction cone being used to gather the liquid flow, and the grinding wheel is provided with a guide cone corresponding to the contraction cone above and below, the guide cone being used to disperse the liquid flow discharged from the contraction cone and guide the liquid flow into the drain hole.

[0013] In one embodiment, the vent hole is positioned higher than the drain hole, and a guide ring is provided on the outer periphery of the contraction cone. The guide ring is connected to the grinding wheel. The top wall of the guide ring is used to guide the airflow in the heat insulation cavity into the vent hole, and the bottom wall of the guide ring is used to guide the liquid flow dispersed by the guide cone to the drain hole.

[0014] In one embodiment, the cone angle of the guide cone is 70° to 110°.

[0015] In one embodiment, the outer sleeve is provided with a drive member located above the bearing core and used to drive the rotating spindle. A first air passage communicating with the heat insulation air cavity is provided between the drive member and the bearing core. The outer sleeve is provided with an air inlet for supplying airflow into the first air passage.

[0016] In one embodiment, the bottom end of the rotating spindle has a connecting plate for connecting with the bearing core, and the peripheral wall of the connecting plate has a plurality of connecting holes for connecting the first connecting air passage and the heat insulation air chamber.

[0017] In one embodiment, a support air passage is provided between the support body and the bearing core, the support air passage being used to introduce high-pressure gas capable of supporting the bearing core.

[0018] In one embodiment, a second air passage is provided between the outer wall of the bearing core and the outer sleeve, the second air passage being used to connect the support air passage and the air inlet.

[0019] In one embodiment, the outer sleeve is provided with a nozzle extending to the liquid passage hole. The lower part of the nozzle is a cone shape with a gradually decreasing cross-sectional area. The nozzle is used to spray liquid into the inner side of the isolation sleeve so that a heat insulation gap is formed between the liquid and the inner wall of the isolation sleeve.

[0020] A second aspect of this application provides a wafer grinding assembly, comprising:

[0021] A support body, on which a bearing core is rotatably mounted, the bearing core having an axially penetrating flow hole, and a grinding wheel connected below the bearing core;

[0022] An outer cover is positioned above the support body;

[0023] A rotating spindle is connected above the bearing core and located inside the outer sleeve. A grinding wheel is connected below the bearing core. The rotating spindle is used to drive the bearing core and the grinding wheel to rotate synchronously to polish the wafer. A liquid passage hole communicating with the flow hole is provided in the middle of the rotating spindle.

[0024] The outer casing is connected to a nozzle that extends downward to the liquid passage hole. The lower part of the nozzle is a cone shape with a gradually decreasing cross-sectional area. The nozzle is used to spray liquid to the bottom of the flow hole and to form a heat insulation gap between the liquid and the inner wall of the flow hole.

[0025] In one embodiment, the nozzle includes:

[0026] A straight connecting segment is disposed on the top of the outer casing. The two ends of the straight connecting segment extend to the upper and lower sides of the top of the outer casing, respectively. The top of the straight connecting segment is used to communicate with the outside, and the bottom of the straight connecting segment extends into the liquid passage hole.

[0027] A transition section is connected to the bottom of the straight connecting section and communicates with the straight connecting section. The transition section is located inside the liquid passage, and the internal cross-sectional area of ​​the transition section gradually decreases.

[0028] In one embodiment, the lower end of the nozzle is connected to a nozzle with an inner diameter of d and a maximum inner diameter of D, where 2d ≤ D ≤ 5d, so that the heat insulation gap can extend to the bottom of the flow hole.

[0029] In one embodiment, the nozzle extends to the lower inner side of the rotating spindle, and the lower part of the nozzle has a cone angle of 10° to 30° to allow the liquid flow to be sprayed to the bottom of the flow hole.

[0030] A third aspect of the embodiments of this application provides a wafer thinning apparatus, including the aforementioned wafer grinding assembly, and further comprising:

[0031] The wafer grinding assembly is elliptically mounted on the base platform;

[0032] An adsorption platform is rotatably mounted on the base. The adsorption platform is used to support adsorption and drive the wafer to rotate, and is located below the grinding assembly.

[0033] A fourth aspect of this application provides a wafer thinning method, which uses the aforementioned wafer thinning apparatus to perform a wafer thinning process, including:

[0034] The grinding assembly is controlled to thin the back side of the wafer on the adsorption platform. Cooling liquid is intermittently introduced into the rotating spindle and the isolation sleeve through the liquid passage, and heat insulation gas is continuously introduced into the heat insulation cavity between the isolation sleeve and the bearing core to form a heat insulation layer between the bearing core and the isolation sleeve. This prevents the liquid introduced by the rotating spindle from directly contacting the bearing core for heat exchange, which could cause the bearing core to deform.

[0035] The beneficial effects of this application embodiment are as follows: by setting an isolation sleeve below the rotating spindle, and while the isolation sleeve penetrates the bearing core, it forms a heat insulation air cavity with the inner wall of the bearing core. The heat insulation air cavity can be filled with gas. Relying on the gas as a poor conductor of heat, it blocks the liquid flow in the rotating spindle from the bearing core, thereby avoiding direct contact between the liquid flow and the bearing core for heat exchange, which would cause deformation of the bearing core, thereby improving the stability and positional accuracy of the bearing core during operation.

[0036] Secondly, the gas inside the insulation chamber can also form a circulating air path with the outside. Through the flow of gas in the circulating air path, heat can be exchanged gently and some of the heat generated by the high-speed rotation of the bearing core can be carried away, thereby ensuring the stability of the bearing core.

[0037] Finally, by connecting the isolation sleeve to the liquid inlet of the rotating spindle and introducing coolant from the top of the rotating spindle, the coolant can contact the rotating spindle for heat exchange, thereby removing the heat transferred to the rotating spindle by the drive components and preventing the bearing core from deforming due to excessively high spindle temperature through contact heat exchange. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the overall structure of a grinding assembly with a central through hole in the prior art;

[0040] Figure 2 This is a schematic diagram of the overall structure of a grinding assembly according to an embodiment of this application;

[0041] Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle;

[0042] Figure 4 for Figure 1 Schematic diagram of the middle and bottom section;

[0043] Figure 5 This is a schematic diagram of the overall grinding assembly according to another embodiment of this application;

[0044] Figure 6 for Figure 6 A schematic diagram of one embodiment of the nozzle and spray nozzle during implementation;

[0045] Figure 7 for Figure 6 A schematic diagram of the second embodiment of the nozzle and spray nozzle in the example;

[0046] Figure 8 for Figure 6 A schematic diagram of the third embodiment of the nozzle and spray nozzle in the example;

[0047] Figure 9 for Figure 2 Schematic diagram of the grinding wheel and guide ring structure in the embodiment;

[0048] Figure 10 This is a schematic diagram of the overall structure of the wafer thinning device of this application;

[0049] Figure label:

[0050] 100. Support body; 110. Support air passage; 112. First connecting air passage; 113. Second connecting air passage.

[0051] 200, bearing core; 210, heat insulation cavity; 220, flow passage.

[0052] 300. Rotary spindle; 310. Fluid passage hole; 320. Connecting plate; 321. Connecting hole; 330. Drive component.

[0053] 400. Grinding wheel; 410. Body; 420. Grinding head; 411. Vent hole; 412. Drain hole; 413. Mounting hole; 431. Guide cone.

[0054] 500, isolation sleeve; 510, thermal insulation gap; 520, contraction cone; 530, flow guide ring.

[0055] 600, Outerwear; 610, Air Intake.

[0056] 710. Nozzle; 711. Straight connecting section; 712. Transition section; 720. Nozzle.

[0057] 800, base; 900, adsorption platform. Detailed Implementation

[0058] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the specific implementation of this application should fall within the protection scope of the embodiments of this application.

[0059] To keep the drawings concise, each drawing only schematically shows the parts relevant to the disclosure; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0060] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0061] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the liquid level of the first feature is higher than that of the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the liquid level of the first feature is lower than that of the second feature.

[0062] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0063] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0064] It should be understood that, unless the context clearly states otherwise, the terms "comprising," "including," or "having" as used herein refer to the presence of an element, but do not exclude the presence or addition of one or more other elements. Furthermore, "comprising" and / or "including" as used herein specify the presence of shapes, numbers, steps, operations, members, elements, and / or combinations thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof. Some embodiments of this application are described in detail below with reference to the accompanying drawings. Where there is no conflict between the embodiments, the following embodiments and features can be combined with each other. The steps in the following method embodiments are for illustrative purposes only and are not intended to limit this application.

[0065] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0066] In the semiconductor manufacturing field, wafer thinning is required before packaging. Wafer thinning devices use an air-static electric spindle to fix a grinding wheel 400, relying on the relative rotational friction between the grinding wheel 400 and the wafer to achieve grinding and thinning of the back side of the wafer. The working principle of the air-static electric spindle is as follows: Precision-filtered compressed air enters the channel of the air-static spindle support 100 through a pipe, then flows through a throttle, and is finally delivered to the gap between the support 100 and the bearing core 200. A pressurized air film is formed in this gap, thus forming an air bearing. Under the pressure of this air film, the bearing core 200 can stably float and rotate through axial connection with the rotating spindle 300 of the drive device.

[0067] However, during the actual operation of the wafer thinning apparatus, the grinding wheel 400 needs to rotate at speeds exceeding 2000 rpm. The gas friction generated between the bearing core 200 and the high-pressure gas, as well as the heat from the motor transferred through the rotating spindle 300, causes the air bearing temperature to rise, resulting in an internal temperature higher than room temperature. This not only alters the physical properties of the air film in the air bearing but also causes thermal expansion of the bearing core 200, ultimately leading to deviation of the machining surface of the grinding wheel 400. This makes it difficult to ensure consistent thinning at different locations on the wafer, affecting the wafer machining accuracy.

[0068] like Figure 1 As shown, to address this issue, the rotating spindle 300 and bearing core 200 employ a central hole design. Room temperature water is intermittently introduced through the central hole of the rotating spindle 300, allowing it to contact the spindle 300 and bearing core 200 for heat exchange and cooling. However, in actual use, the heat exchange between the room temperature water and the bearing core 200 affects the thickness of the air film in different areas of the air bearing, thus impacting the operational stability of the bearing core 200. Furthermore, the heat exchange between the room temperature water and the bearing core 200 can cause unstable deformation of the bearing core 200, thereby affecting the machining surface accuracy of the grinding wheel 400.

[0069] To mitigate the impact of central water circulation on the internal temperature variations of the bearing core 200, which could lead to reduced wafer machining accuracy, such as... Figures 2-4 As shown, in a first aspect of the present application, a wafer grinding assembly is provided. The wafer grinding assembly includes a support body 100, a bearing core 200 rotatably mounted on the support body 100 via a high-pressure air film, a rotating spindle 300 connected above the bearing core 200 by fasteners, a grinding wheel 400 connected below the bearing core 200 by fasteners, and an isolation sleeve 500 connected to the lower end of the rotating spindle 300 by fasteners.

[0070] A liquid passage hole 310 is provided in the middle of the rotating spindle 300 for liquid to enter and pass through the rotating spindle 300 axially. The interior of the isolation sleeve 500 communicates with the liquid passage hole 310, axially penetrates the bearing core 200, and a heat-insulating air cavity 210 is formed between the outer wall of the isolation sleeve 500 and the bearing core 200. The heat-insulating air cavity 210 is connected to an external air source, so that the external air source can continuously enter the heat-insulating air cavity 210. Specifically, the bearing core 200 has an axial through hole with a diameter larger than that of the isolation sleeve 500 at its central axis. The axial through hole has several radial through holes for communicating with an external air source. The isolation sleeve 500 is located in the axial through hole and does not directly contact the inner wall of the axial through hole of the bearing core 200. Preferably, the isolation sleeve 500 is cylindrical, and its central axis coincides with the central axis of the bearing core 200.

[0071] During wafer grinding, the rotating spindle 300 is driven by the drive component 330, causing the bearing core 200 and the grinding wheel 400 to rotate synchronously, grinding the wafer below. Simultaneously, cooling liquid is intermittently introduced through the liquid inlet 310, flowing through the isolation sleeve 500, while insulating gas is continuously introduced into the heat insulation chamber 210. Utilizing the property that gas is a poor conductor of heat, an insulating layer is formed between the bearing core 200 and the isolation sleeve 500, preventing the cooling liquid from directly contacting and exchanging heat with the bearing core 200, thereby preventing deformation of the bearing core 200 and ensuring the stability and precision of the grinding wheel 400.

[0072] Secondly, by connecting the isolation sleeve 500 to the liquid passage hole 310 of the rotating spindle 300 and introducing cooling liquid from the top of the rotating spindle 300, the cooling liquid can contact the rotating spindle 300 for heat exchange, thereby removing the heat transferred from the drive component 330 to the rotating spindle 300, and preventing the bearing core 200 from thermally deforming due to excessive temperature of the rotating spindle 300 through contact heat exchange.

[0073] Preferably, the gas in the heat insulation cavity 210 can also form a circulating heat exchange air path with the outside. Through the flow of gas in the circulating air path, heat can be exchanged gently and some of the heat generated by the high-speed rotation of the bearing core 200 can be removed, thereby avoiding different temperature changes in different areas caused by the drastic temperature change of the bearing core 200, thus ensuring the stability of the bearing core 200.

[0074] Preferably, the isolation sleeve 500 is made of a rigid material with low thermal conductivity, such as alumina ceramic or piezoelectric ceramic.

[0075] Furthermore, since the gas in the heat insulation cavity 210 experiences a temperature increase after heat exchange with the bearing core 200, based on the above embodiment, the outer wall of the isolation sleeve 500 is designed to be narrower at the top and wider at the bottom. This allows the gas in the heat insulation cavity 210 to gradually accumulate after heat exchange with the bearing core 200. As the gas volume increases, the same temperature increase will carry away more heat from the bearing core 200. This gradual change in the space of the heat insulation cavity 210 avoids uneven heat changes between the top and bottom of the bearing core 200, thereby further ensuring the stability of the bearing core temperature change.

[0076] Since gas is a poor conductor of heat, to avoid wasting gas, the angle between the outer wall of the isolation sleeve 500 and the central axis is 3°~5°.

[0077] like Figure 2As shown, the support body 100 has an outer sleeve 600 integrally formed or welded to its top. The outer sleeve 600 is preferably cylindrical, and the rotating spindle 300 is located inside the outer sleeve 600. Preferably, the rotating drive component 330 is a motor, which is fixed inside the outer sleeve 600 by fasteners. The rotating spindle 300 is the drive end of the rotating drive component 330, that is, the rotating spindle 300 serves as the rotor of the rotating drive component 330.

[0078] The outer casing 600 contains a nozzle 710 extending to the liquid passage 310. The top of the nozzle 710 is fixedly connected to the top of the outer casing 600 by fasteners and extends downward into the liquid passage 310 located inside the rotating main shaft 300 within the outer casing 600. For ease of description, the nozzle 710 is divided into upper and lower parts: the upper part is cylindrical, and the lower part is tapered with a gradually decreasing cross-sectional area. The outer wall of the upper part of the nozzle 710 can directly abut against the inner wall of the liquid passage 310, or it can be connected to the inner wall of the liquid passage 310 via a bearing. When the outer wall of the upper part of the nozzle 710 directly abuts against the inner wall of the liquid passage 310, both the outer wall of the nozzle 710 and the inner wall of the liquid passage 310 need to be polished to reduce the friction between them. When the upper part of the nozzle 710 outer wall is connected to the inside of the liquid passage 310 by a bearing, a bearing with good thermal conductivity should be selected.

[0079] The external water source is connected to the liquid passage 310 via the nozzle 710. The external water source only needs to be connected to the fixed nozzle 710 through a pipe. Compared with the external pipe being directly connected to the high-speed rotating spindle 300, it is not only easier to install, but also has better sealing performance.

[0080] The conical shape of the lower part of the nozzle 710 creates a converging effect, allowing the coolant to flow out from the bottom of the nozzle 710 and be positioned at the center of the liquid passage 310 without contacting the outer wall of the liquid passage 310. This ensures that the coolant does not contact the inner wall of the isolation sleeve 500 after entering the isolation sleeve 500, thus forming a heat insulation gap 510 between the coolant and the inner wall of the isolation sleeve 500 to prevent direct heat exchange between the coolant and the isolation sleeve 500.

[0081] The convergence of the flow through the nozzle 710 creates a heat insulation gap 510 between the cooling liquid sprayed below the nozzle 710 and the inner wall of the isolation sleeve 500. Combined with the heat insulation air cavity 210 between the isolation sleeve 500 and the bearing core 200, a triple heat insulation layer is formed between the cooling liquid and the bearing core 200, thereby avoiding the thermal deformation of the bearing core 200 caused by the liquid passing through the bearing core 200.

[0082] Furthermore, to increase the stability of the liquid discharged from the bottom of the nozzle 710 and entering the isolation sleeve 500, a nozzle 720 is connected to the bottom of the nozzle 710. Using the pressure generated by the external water source, the cooling liquid in the nozzle 710 generates a water jet effect through the nozzle 720, so that the cooling liquid entering the isolation sleeve 500 can form a stable heat insulation gap 510 with the inner wall of the isolation sleeve 500.

[0083] The external water source can generate a water flow pressure of 0.3~0.6MPa. The inner diameter of the nozzle 720 is set as d, and the maximum inner diameter of the nozzle 710 is set as D. Preferably, 2d≤D≤5d is satisfied. The ratio between D and d should not be too small or too large. Assuming the maximum inner diameter of the nozzle 710 remains constant, if the inner diameter of the nozzle 720 is too small, the water flow velocity ejected from the nozzle 720 will be too high, which will not only generate whistling and turbulent noise, but also cause the water flow to be torn into droplets, failing to form a concentrated water column. This results in the cooling liquid escaping in droplet form and adhering to the inner wall of the isolation sleeve 500, enhancing the heat exchange between the cooling liquid and the isolation sleeve 500. The isolation sleeve 500 can exchange heat with the gas in the heat insulation chamber 210, which is detrimental to the stable heat exchange between the gas in the heat insulation chamber 210 and the bearing core 200. Furthermore, if the inner diameter of the nozzle 720 is too large, the initial diameter of the liquid stream ejected from the nozzle 720 will be large. Due to air resistance, the liquid stream will spread in a conical shape as it moves away from the nozzle 720, causing it to contact the inner wall of the isolation sleeve 500 after traveling a certain distance away from the nozzle 720. This results in the disappearance of the heat insulation gap 510 and a reduction in the heat insulation effect. Only when the relationship between the inner diameter of the nozzle 720 and the maximum diameter of the nozzle 710 satisfies 2d ≤ D ≤ 5d can it be guaranteed that the liquid stream, after leaving the nozzle 720 and entering the isolation sleeve 500, can move to the bottom of the isolation sleeve 500 without contacting the inner wall of the isolation sleeve 500.

[0084] Preferably, the inner diameter of the bottom of the nozzle 710 matches the inner diameter of the nozzle 720, and the cone angle of the lower conical part of the nozzle 710 is 10°~30°. If the cone angle of the lower conical part of the nozzle 710 is too small, the axial distance from the upper cylindrical part of the nozzle 710 to the predetermined size will be too long. This will not only increase the overall volume of the equipment, but also cause a pressure drop due to the excessive liquid flow distance, preventing the formation of the predetermined water flow state at the nozzle 720. Conversely, if the cone angle of the lower conical part of the nozzle 710 is too small, the axial distance from the upper cylindrical part of the nozzle 710 to the predetermined size will be too short. This will not only hinder heat exchange between the cooling liquid and the nozzle 710, but also increase the pressure loss due to water flow impact due to the excessively large cone angle, thus affecting the liquid ejection effect from the nozzle 720. By setting the cone angle of the lower part of the nozzle 710 to 10°~30°, when the external water pressure is 0.3~0.6MPa, the pressure loss of the cooling liquid when passing through the nozzle 710 can be minimized, and the contact distance between the cooling liquid and the nozzle 710 can be guaranteed. The longer the contact time between the cooling liquid and the nozzle 710, the better the cooling effect of the nozzle 710 through its own heat transfer, thereby avoiding the nozzle 710 from heating up too quickly.

[0085] like Figure 4 As shown, a radially extending vent hole 411 is provided inside the grinding wheel 400, penetrating the peripheral wall of the grinding wheel 400, and one end of the vent hole 411 is connected to the heat insulation chamber 210. Gas is introduced into the heat insulation chamber 210 from one end, and the gas enters the vent hole 411 from the other end of the heat insulation chamber 210 and exits from the vent hole 411. This allows the gas within the heat insulation chamber 210 to flow, thereby continuously and stably removing the heat generated by the friction between the bearing core 200 and the gas film. Furthermore, the vent hole 411 also cools the grinding wheel 400, preventing it from overheating and affecting machining accuracy.

[0086] Preferably, the outer wall of the isolation sleeve 500 is integrally formed or machined with outwardly protruding threads. The direction of the threads is related to the rotation direction of the isolation sleeve 500. On the one hand, as the isolation sleeve 500 rotates with the rotating spindle 300, the rotation of the isolation sleeve 500 and the effect of the threads can guide the gas in the heat insulation cavity 210 to move downward. On the other hand, the threads on the outer wall of the isolation sleeve 500 can cause the gas entering the heat insulation cavity 210 to form a circumferential rotating turbulence, thereby allowing the gas to spiral downward, further improving the uniformity of heat exchange between the gas in the heat insulation cavity 210 and the bearing core 200, and avoiding local overheating of the bearing core 200 that could lead to thermal deformation.

[0087] like Figure 4As shown, a radially extending drain hole 412 is provided inside the grinding wheel 400. One end of the drain hole 412 communicates with the interior of the isolation sleeve 500, and the other end radially penetrates the grinding wheel 400, or the other end communicates with a channel that is vertically downward at one end, so that the cooling liquid can be discharged from the side or bottom of the grinding wheel 400. The cooling liquid entering the interior of the isolation sleeve 500 through the nozzle 720 can flow into the drain hole 412 from the bottom of the isolation sleeve 500. The radial extension of the drain hole 412 not only serves to discharge the cooling liquid, but also allows the cooling liquid to exchange heat with the grinding wheel 400, thus cooling the grinding wheel 400.

[0088] When the drain hole 412 radially penetrates the outer wall of the grinding wheel 400 and communicates with the outside, a baffle should be provided on the outer wall of the grinding wheel 400. The baffle is generally annular and is welded or fastened to the outer peripheral wall of the grinding wheel 400. After the cooling liquid in the drain hole 412 is discharged, the baffle can prevent the liquid from spreading in all directions and allow the cooling liquid to fall onto the wafer undergoing thinning under the action of gravity after colliding with the baffle, thereby cooling the wafer. (Reference) Figure 4 Preferably, the end of the drain hole 412 away from the isolation sleeve 500 does not penetrate the side wall of the grinding wheel 400, but instead extends downward through the end face of the main body 410 of the grinding wheel 400. The outlet of the drain hole 412 is located inside the grinding head 420 of the grinding wheel 400 and is inclined towards the grinding head 420. The liquid discharged through the drain hole 412 first splashes onto the grinding head 420 of the grinding wheel 400 and then falls onto the wafer undergoing thinning process by gravity, so that the cooling liquid can cool the grinding head 420 and the wafer of the grinding wheel 400 again.

[0089] like Figure 4 As shown, in one embodiment, a contraction cone 520 is integrally formed or welded to the lower end of the isolation sleeve 500. A mounting hole is provided at the center of the main body 410 of the grinding wheel 400, and the contraction cone 520 extends into the mounting hole of the grinding wheel 400. The contraction cone 520 is generally conical in shape, and its interior communicates with the interior of the isolation sleeve 500, with a gradually decreasing cross-sectional area. The contraction cone 520 can collect the liquid flowing out of the isolation sleeve 500. Corresponding to the contraction cone 520, a guide cone 431 is welded to or integrally formed at the bottom of the mounting hole. The guide cone 431 is preferably a cone with its tip pointing upwards. The cooling liquid discharged through the contraction cone 520 falls onto the guide cone 431, and through the guiding action of the guide cone 431, the cooling liquid is directed radially towards the grinding wheel 400, thereby allowing the cooling liquid to be discharged along the radial drain hole 412.

[0090] Preferably, the cone angle of the guide cone 431 is 70°~110°. By setting the contraction cone 520 and the guide cone 431, the cooling liquid flowing vertically inside the isolation sleeve 500 can be smoothly transitioned into the horizontal drain hole 412.

[0091] The arrangement of the drain hole 412 and vent hole 411 on the grinding wheel 400 is as follows: the height of the vent hole 411 is higher than the height of the drain hole 412, and both the vent hole 411 and the drain hole 412 are connected to the mounting hole at the center of the grinding wheel 400. To prevent gas and liquid from mixing in the mounting hole of the grinding wheel 400, a guide ring 530 is integrally formed or welded to the periphery of the contraction cone 520. The outer wall of the guide ring 530 is in sealing contact with the inner wall of the mounting hole, and the position where the guide ring 530 abuts against the inner wall of the mounting hole is located between the drain hole 412 and the vent hole 411. The specific sealing method can be a sealing gasket. The guide ring 530 can form an upper and lower layer effect in the mounting hole, thereby isolating the drain hole 412 and the vent hole 411. The vent hole 411 is connected to the upper area of ​​the guide ring 530, and the drain hole 412 is connected to the lower area of ​​the guide ring 530, with the guide cone 431 located in the lower area.

[0092] The arrangement of the vent hole 411 above the drain hole 412 corresponds to the arrangement where gas is located outside the isolation sleeve 500 and liquid is located inside the isolation sleeve 500. This allows the grinding wheel 400 to achieve segmented discharge of liquid from the drain hole 412 and the vent hole 411 using the simplest machining method. Furthermore, an upwardly recessed guide groove is provided on the bottom wall of the guide ring 530. Liquid flowing out from the contraction cone 520, after falling onto the guide cone 431, will form an upward backflow due to the impact force of the liquid. The guide groove can guide this upward backflow, allowing the liquid to flow more smoothly into the drain hole 412.

[0093] like Figure 9 As shown, in one embodiment, a grinding wheel 400 is disposed at the bottom of a bearing core 200 for grinding wafers, comprising: a body 410 disposed at the bottom of the bearing core 200, the body 410 having a horizontally extending vent hole 411 and a drain hole 412 respectively communicating with a gas passage and a liquid passage within the bearing core 200, the vent hole 411 penetrating the outer wall of the body 410, and the drain hole 412 penetrating the outer wall or end face of the body 410, the gas in the vent hole 411 and the liquid in the drain hole 412 being used for cooling the body 410; and a grinding head 420 disposed at the bottom of the body 410 for grinding wafers.

[0094] Preferably, the main body 410 is made of an alloy, preferably an aluminum alloy. Aluminum alloy is not only lightweight and rigid but also dissipates heat quickly. The main body 410 is manufactured by a modular assembly method so that the drain hole 412 and the vent hole 411 on the main body 410 can be machined and formed by milling and drilling.

[0095] Preferably, the grinding head 420 is made of single-crystal / polycrystalline diamond, the grinding head 420 has a block structure, and there are several grinding heads 420 distributed in a circular interval on the main body 410.

[0096] Preferably, the grinding head 420 and the body 410 are connected by a resin adhesive.

[0097] Specifically, the main body 410 is cylindrical, and a mounting hole 413 is provided in the center of the main body 410. The height of the drain hole 412 is lower than the height of the vent hole 411. Both the drain hole 412 and the vent hole 411 are connected to the mounting hole 413. It also includes a guide ring 530, which is disposed in the mounting hole 413. The guide ring 530 can block the communication path between the drain hole 412 and the vent hole 411 in the mounting hole 413, so that the air passage and liquid passage in the bearing core 200 are connected to the vent hole 411 and the drain hole 412 respectively.

[0098] Preferably, the outer wall of the guide ring 530 abuts against the inner wall of the mounting hole 413 between the drain hole 412 and the vent hole 411, and the interior of the guide ring 530 is connected to the interior of the isolation sleeve 500, so that the guide ring 530 can separate the drain hole 412 and the vent hole 411 by means of upper and lower layers.

[0099] Preferably, a guide cone 431 is also provided in the mounting hole 413. The guide cone 431 is conical and can guide the liquid in the internal liquid path of the bearing core 200 from the longitudinal direction to the transverse drain hole 412.

[0100] Preferably, the bottom wall of the guide ring 530 is provided with an upwardly recessed guide groove, which can guide the upward splashed liquid to flow into the drain hole 412.

[0101] like Figure 2 and Figure 3 As shown, in one embodiment, the drive component 330 for driving the rotating spindle 300 to rotate is located above the bearing core 200. A first connecting air passage 112 is opened between the drive component 330 and the bearing core 200, and the air inlet 610 of the first connecting air passage 112 is located on the outer casing 600. The first connecting air passage 112 is connected to the heat insulation chamber 210. By introducing compressed air into the air inlet 610, a heat insulation layer can be formed not only in the heat insulation chamber 210, but also between the bearing core 200 and the drive component 330. This prevents the heat generated by the drive component 330 from being transferred to the outer casing 600 and then to the bearing core 200 through contact heat transfer.

[0102] In one embodiment, a connecting plate 320 is welded or integrally formed to the bottom end of the rotating spindle 300. The bearing core 200 and the isolation sleeve 500 are both connected to the bottom of the connecting plate 320 by fasteners or snap-fit. The connecting plate 320 has a transition hole communicating with the fluid passage 310 and the interior of the isolation sleeve 500. The outer diameter of the connecting plate 320 is larger than the outer diameter of the rotating spindle 300 to form a larger installation space, so that both the bearing core 200 and the isolation sleeve 500 can be connected to the bottom of the connecting plate 320.

[0103] Preferably, the peripheral wall of the connecting plate 320 has several circumferentially distributed connecting holes, which are divided into horizontal and vertical sections. The horizontal connecting holes penetrate the outer wall of the connecting plate 320 and extend radially toward the center of the connecting plate 320. When the connecting holes extend to the top of the heat insulation air cavity 210, a vertical connecting section penetrates axially at the bottom of the connecting plate 320, communicating with the horizontal connecting section and the heat insulation air cavity 210. When compressed gas enters the first communicating air passage 112 through the air inlet 610, the gas enters the connecting holes under pressure and passes through the horizontal and vertical connecting sections in sequence into the heat insulation air cavity 210.

[0104] like Figure 2 As shown, in one embodiment, a supporting air passage 110 is provided between the support body 100 and the bearing core 200. The supporting air passage 110 is arranged on the outer periphery of the bearing core 200, and high-pressure gas is introduced into it, which can form a stable supporting air film between the support body 100 and the bearing core 200. The air film can support the bearing core 200. The cross-section of the supporting air passage 110 is L-shaped, which can provide not only radial support force to the bearing core 200, but also axial support force, so that the bearing core 200 can rotate with the rotating spindle 300 while ensuring positional accuracy and stability.

[0105] Preferably, a second connecting air passage 113 is provided between the outer wall of the bearing core 200 and the outer sleeve 600. The second connecting air passage 113 is used to connect the supporting air passage 110 and the air inlet 610, thereby realizing that air is supplied to both the supporting air passage 110 and the heat insulation air cavity 210 at the same time through the air inlet 610. Figure 2 As shown, the second connecting air passage 113 is connected to the first connecting air passage 112. Optionally, the first air passage and the second air passage are connected to the air inlet 610 respectively, or the first connecting air passage 112 and the second connecting air passage 113 are connected to the two air inlets 610 respectively, and the two air inlets 610 are connected externally by a three-way port.

[0106] like Figure 5 , Figure 6As shown, in another embodiment, the bearing core 200 does not have an isolation sleeve 500 inside. Specifically, it includes an outer sleeve 600, a rotating spindle 300, the bearing core 200, a nozzle 710, and a nozzle 720. The positional relationship between the nozzle 710, nozzle 720, and rotating spindle 300, as well as the shapes of the nozzle 710 and nozzle 720, are the same as in the above embodiment and will not be repeated here. The bearing core 200 has a flow hole 220 communicating with the liquid passage 310. The cooling liquid inside the rotating spindle 300 directly enters the flow hole 220 in a conical manner through the nozzle 710 and nozzle 720, and finally exits from the drain hole 412 of the grinding wheel 400. The liquid flow ejected from the nozzle 710 and nozzle 720 diffuses in a conical form, which can form a heat insulation gap 510 between the cooling liquid and the bearing core 200. The heat insulation gap 510 can prevent the cooling liquid from directly contacting the bearing core 200.

[0107] The cooling liquid sprayed through nozzle 720 does not directly contact the bearing core 200, thus preventing large temperature changes in the bearing core 200 from causing deviations in its position or shape. Meanwhile, the cooling water passing through nozzle 710 can exchange heat with the rotating spindle 300 through contact with the spindle 300, thereby achieving a heat exchange and cooling effect between the cooling water and the rotating spindle 300 and the grinding wheel 400 without affecting the bearing core 200.

[0108] Preferably, the nozzle 710 should be made of a material with high thermal conductivity, such as copper, oxygen-free copper, or diamond.

[0109] Specifically, the nozzle 710 includes a straight connecting section 711 and a straight connecting section 712. A raised ring for connection to the outer casing 600 is integrally formed or welded to the outer wall of the middle portion of the straight connecting section 711. The raised ring is connected to the top of the outer casing 600 by bolts. The straight connecting section 711 is generally cylindrical. The top of the straight connecting section 711 is connected to a water source via a pipe. The portion of the straight connecting section 711 below the raised ring extends into the liquid passage 310. A straight connecting section 712 is integrally formed or welded to the bottom of the straight connecting section 711. The straight connecting section 712 communicates with the bottom of the straight connecting section 711. The straight connecting section 712 is divided into a large-diameter end and a small-diameter end, with the large-diameter end located at the top and the small-diameter end at the bottom, so that the internal liquid flow of the straight connecting section can converge after entering the straight connecting section 712 and be ejected from the small-diameter end.

[0110] like Figure 7 , Figure 8 As shown, the shape of the transition end can optionally be a straight cone, a gradually tapered cone, or a stepped shape.

[0111] like Figure 10As shown, a wafer thinning apparatus includes the aforementioned wafer grinding assembly, a base 800, and an adsorption platform 900, with the base 800 serving as the main support component. The wafer grinding assembly is lifted and lowered on the base 800 via an electric cylinder, pneumatic cylinder, or hydraulic cylinder. The adsorption platform 900 is rotatably mounted on the base 800, capable of supporting and adsorbing the wafer under negative pressure. This allows the wafer to remain fixed relative to the wafer grinding assembly during the thinning process, and also enables the adsorption platform 900 to rotate the wafer undergoing the thinning process, thereby improving the efficiency of the wafer thinning process.

[0112] Based on the above embodiments, the wafer thinning apparatus further includes a controller, which is used to control the fluid flow and airflow of the wafer grinding assembly; specifically, the controller can control the fluid flow and airflow of the wafer grinding assembly in the following ways:

[0113] When the wafer grinding assembly is in standby or idling mode (i.e., when there is no grinding action), the corresponding liquid supply module is controlled to intermittently supply liquid at preset time intervals to ensure that the liquid flow channels of the wafer grinding assembly maintain a small amount of pre-filled liquid, preventing dry burning or internal vacuum due to prolonged lack of liquid flow. Simultaneously, the corresponding gas supply module is controlled to supply gas to the wafer grinding assembly at a first preset gas flow rate, using a small flow rate (20% of the maximum flow rate) to form a basic heat-insulating gas film. This preheats the piping to prevent thermal shock and maintains the internal thermal balance of the wafer grinding assembly without wasting energy.

[0114] When the wafer grinding assembly is in the grinding process, the flow rate of the coolant supply module is determined based on the spindle speed, and the coolant supply is controlled using this determined flow rate. For example, at low spindle speeds (<50% of rated speed), 50% of the coolant flow rate is used to prevent overheating due to heat accumulation at low speeds. At medium speeds (50%-80% of rated speed), 80% of the coolant flow rate is used to provide adequate heat dissipation. At high speeds (>80% of rated speed), 100% of the coolant flow rate is used to cope with the enormous frictional heat generated at high speeds.

[0115] At the same time, the gas supply module's gas supply volume is increased to the second preset gas flow rate (the second preset gas flow rate can be 50% of the maximum flow rate), forming a continuous heat insulation film to block heat transfer upwards.

[0116] When the wafer grinding assembly is in the grinding end stage or the tool retraction stage (that is, when the current time period is within the preset time period after grinding stops), the corresponding liquid supply module is controlled to supply liquid at the first preset liquid flow rate for a preset time. For example, after the tool retraction, the liquid supply control module continues to turn on the coolant at 30% flow rate and maintains cooling for 30 seconds to prevent the grinding wheel 400 from deforming or cracking due to sudden cooling.

[0117] When the wafer grinding assembly is in the grinding completion stage or tool retraction stage, after detecting that the temperature of the grinding wheel 400 is lower than the preset temperature, the air supply volume of the air supply module is adjusted back to the first preset air flow rate. Specifically, the air supply volume is switched back to the low flow rate state of the standby stage only after the temperature of the grinding wheel 400 drops below the preset temperature (e.g., 50°C) to prevent thermal shock caused by premature switching.

[0118] A wafer thinning method utilizes the aforementioned wafer thinning device to thin the wafer. The specific steps are as follows: The wafer is placed with its back side facing up on an adsorption platform 900, and then the back side of the wafer is thinned using a grinding assembly. During the processing, cooling liquid is intermittently introduced into the rotating spindle 300 and the isolation sleeve 500 through the liquid inlet 310, while heat-insulating gas is continuously introduced into the heat-insulating gas cavity 210 between the isolation sleeve 500 and the bearing core 200. This forms a heat-insulating layer between the bearing core 200 and the isolation sleeve 500, preventing the liquid introduced by the rotating spindle 300 from directly contacting and exchanging heat with the bearing core 200, which could cause deformation of the bearing core 200, thus ensuring the wafer grinding accuracy.

[0119] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wafer grinding assembly, characterized in that, include: A support body (100) on which a bearing core (200) is rotatably disposed; A rotating spindle (300) is connected above the bearing core (200), and a grinding wheel (400) is connected below the bearing core (200). The rotating spindle (300) is used to drive the bearing core (200) and the grinding wheel (400) to rotate synchronously to polish the wafer. The rotating spindle (300) is provided with a liquid passage hole (310) in the middle for axial penetration of liquid. An isolation sleeve (500) is connected to the lower end of the rotating spindle (300) and communicates with the liquid passage hole (310) for the liquid flow in the liquid passage hole (310) to pass through. The isolation sleeve (500) is disposed through the bearing core (200). A heat insulation air cavity (210) is formed between the isolation sleeve (500) and the bearing core (200). The heat insulation air cavity (210) is used to introduce airflow to insulate the bearing core (200). The grinding wheel (400) has an exhaust hole (411) communicating with the heat insulation chamber (210) and a drain hole (412) communicating with the isolation sleeve (500). The exhaust hole (411) is set higher than the drain hole (412). The exhaust hole (411) penetrates the peripheral wall of the grinding wheel (400) to discharge the gas in the heat insulation chamber (210) and cool the grinding wheel (400). The drain hole (412) penetrates the peripheral wall of the grinding wheel (400) to discharge the liquid in the isolation sleeve (500) and cool the grinding wheel (400) and the wafer. The outer wall of the isolation sleeve (500) is provided with a threaded part, which can guide the gas in the heat insulation chamber (210) to be discharged when the isolation sleeve (500) rotates.

2. The wafer grinding assembly as described in claim 1, characterized in that, The lower end of the isolation sleeve (500) is provided with a contraction cone (520) extending into the grinding wheel (400). The contraction cone (520) is used to gather the liquid flow. The grinding wheel (400) is provided with a guide cone (431) corresponding to the contraction cone (520) above and below. The guide cone (431) is used to disperse the liquid flow discharged from the contraction cone (520) and guide the liquid flow into the drain hole (412).

3. A wafer grinding assembly as described in claim 2, characterized in that, A guide ring (530) is provided on the outer periphery of the contraction cone (520). The guide ring (530) is connected to the grinding wheel (400). The top wall of the guide ring (530) is used to guide the airflow in the heat insulation chamber (210) into the exhaust hole (411). The bottom wall of the guide ring (530) is used to guide the liquid flow dispersed by the guide cone (431) to the drain hole (412) for a secondary purpose.

4. A wafer grinding assembly as described in claim 2, characterized in that, The cone angle of the guide cone (431) is 70°~110°.

5. A wafer grinding assembly as described in claim 1, characterized in that, An outer sleeve (600) is provided above the support body (100). Inside the outer sleeve (600) is a drive member (330) located above the bearing core (200) and used to drive the rotating spindle (300). A first connecting air passage (112) is provided between the drive member (330) and the bearing core (200) and communicates with the heat insulation air chamber (210). An air inlet (610) is provided on the outer sleeve (600) for supplying airflow into the first connecting air passage (112).

6. A wafer grinding assembly as described in claim 5, characterized in that, The bottom end of the rotating spindle (300) has a connecting plate (320) for connecting with the bearing core (200), and the peripheral wall of the connecting plate (320) has a plurality of connecting holes (321) for connecting the first connecting air passage (112) and the heat insulation air chamber (210).

7. A wafer grinding assembly as described in claim 5, characterized in that, There is a support air passage (110) between the support body (100) and the bearing core (200), the support air passage (110) is used to introduce high-pressure gas that can support the bearing core (200).

8. A wafer grinding assembly as described in claim 7, characterized in that, The outer wall of the bearing core (200) and the outer sleeve (600) have a second connecting air passage (113), which is used to connect the supporting air passage (110) and the air inlet (610).

9. A wafer grinding assembly as described in claim 5, characterized in that, The outer sleeve (600) is provided with a nozzle (710) extending to the liquid passage (310). The lower end of the nozzle (710) has a tapered shape with a gradually decreasing cross-sectional area. The nozzle (710) is used to spray liquid into the lower opening inside the isolation sleeve (500) so that a heat insulation gap (510) is formed between the liquid and the inner wall of the isolation sleeve (500).

10. A wafer grinding assembly, characterized in that, include: A support body (100) is provided with a bearing core (200) rotatably mounted on the support body (100). The bearing core (200) has an axially penetrating flow hole (220). A grinding wheel (400) is connected below the bearing core (200). An outer cover (600) is disposed above the support (100); A rotating spindle (300) is connected above the bearing core (200) and located inside the outer sleeve (600). The rotating spindle (300) is used to drive the bearing core (200) and the grinding wheel (400) to rotate synchronously to polish the wafer. The rotating spindle (300) has a liquid passage hole (310) in the middle that communicates with the flow passage hole (220). The outer jacket (600) is connected to a nozzle (710) extending downward to the liquid passage (310). The nozzle (710) is used to spray liquid to the bottom of the flow passage (220) and to form a heat insulation gap (510) between the liquid and the inner wall of the flow passage (220). The nozzle (710) includes: A straight connecting section (711) is used to extend through the top wall of the outer casing (600) into the liquid passage (310), and the top of the straight connecting section (711) is used to communicate with an external liquid supply component; The transition section (712) is connected to the lower end of the straight connecting section (711) and communicates with the straight connecting section (711). The transition section (712) is located inside the liquid passage hole (310). The cross-sectional area of ​​the inner cavity of the transition section (712) gradually decreases from top to bottom so that the heat insulation gap (510) can extend to the bottom of the flow hole (220).

11. A wafer grinding assembly as described in claim 10, characterized in that, The lower end of the nozzle (710) is connected to a nozzle (720), the inner diameter of the nozzle (720) is d, the maximum inner diameter of the nozzle (710) is D, and 2d≤D≤5d.

12. A wafer grinding assembly as described in claim 10, characterized in that, The nozzle (710) extends to the lower inner side of the rotating main shaft (300), and the cone angle of the lower part of the nozzle (710) is 10°~30° so that the liquid flow can be sprayed to the bottom of the flow hole (220).

13. A wafer thinning apparatus, characterized in that, The wafer grinding assembly comprising any one of claims 1 to 9 further comprises: A base (800) on which the wafer grinding assembly is ellipsably mounted; An adsorption platform (900) is rotatably mounted on the base (800). The adsorption platform (900) is used to support adsorption and drive the wafer to rotate, and is located below the grinding assembly.

14. A wafer thinning apparatus, characterized in that, The wafer grinding assembly comprising any one of claims 10 to 12 further comprises: A base (800) on which the wafer grinding assembly is ellipsably mounted; An adsorption platform (900) is rotatably mounted on the base (800). The adsorption platform (900) is used to support adsorption and drive the wafer to rotate, and is located below the grinding assembly.

15. A wafer thinning method, comprising using the wafer thinning apparatus of claim 13 to perform wafer thinning processing, characterized in that, include: The grinding assembly is controlled to perform thinning processing on the back side of the wafer on the adsorption platform (900). Cooling liquid is intermittently introduced into the rotating spindle (300) and the isolation sleeve (500) through the liquid passage (310), and heat insulation gas is continuously introduced into the heat insulation gas cavity (210) between the isolation sleeve (500) and the bearing core (200) to form a heat insulation layer between the bearing core (200) and the isolation sleeve (500), so as to avoid the liquid introduced by the rotating spindle (300) directly contacting the bearing core (200) for heat exchange, which would cause the bearing core (200) to deform.

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