A cleaning brush assembly and wafer cleaning apparatus

Abstract

The application discloses a cleaning brush assembly and a wafer cleaning device. The cleaning brush assembly comprises a middle shaft and a porous material brush body. The porous material brush body covers the outer surface of the middle shaft and forms an integral whole. The middle shaft is a hollow structure to form a liquid passage through both ends of the length. The shaft wall of the middle shaft has a plurality of uniformly distributed liquid outlets and a plurality of uniformly distributed long strip-shaped grooves. The liquid outlets pass through the shaft wall of the middle shaft. The length of the long strip-shaped grooves is parallel to the length of the middle shaft. The depth of the long strip-shaped grooves is less than the thickness of the shaft wall of the middle shaft. At least two liquid outlets are arranged in the long strip-shaped grooves. The wafer cleaning device comprises a box body, a wafer rotating assembly and the cleaning brush assembly.

Description

Technical Field

[0001] This invention relates to the field of post-chemical mechanical polishing (CMP) processing technology, and more particularly to a cleaning brush assembly and a wafer cleaning device. Background Technology

[0002] In the semiconductor industry, wafer surface cleanliness is a crucial factor affecting the reliability of semiconductor devices. During wafer fabrication processes such as deposition, plasma etching, photolithography, and electroplating, contaminants and / or particles can be introduced onto the wafer surface, leading to decreased surface cleanliness and low yields of manufactured semiconductor devices. Chemical Mechanical Polishing (CMP) is an ultra-precision surface processing technology that achieves global planarization. However, the large amounts of chemical reagents and abrasives used in CMP leave significant residues of abrasive particles and byproducts on the wafer surface after polishing, which can adversely affect subsequent processes.

[0003] To achieve a contaminant-free wafer surface, contaminants need to be removed to prevent them from re-entering the wafer surface before the manufacturing process. Therefore, multiple surface cleaning processes are required during wafer manufacturing to remove contaminants such as metal ions, atoms, organic matter, and particles adhering to the wafer surface.

[0004] Wafer cleaning methods include roller brush cleaning and megasonic cleaning, among which roller brush cleaning is more widely used. Patent CN102768974B discloses a wafer cleaning device. The wafer cleaning device includes: a rack; a wafer cleaning device mounted on the rack; a wafer brushing device mounted on the rack and located downstream of the wafer cleaning device; a wafer drying device mounted on the rack and located downstream of the wafer brushing device; and a robotic arm movably mounted on the rack for vertically holding and transporting wafers.

[0005] However, the existing roller brush structure is unreasonable. It is difficult to achieve uniform distribution of liquid supply inside the roller brush. Uneven axial liquid output leads to uneven liquid wetting effect on the roller brush surface. The brushing force applied to the wafer by the roller brush surface is unevenly distributed, which in turn affects the final cleaning effect of the wafer. Summary of the Invention

[0006] This invention provides a cleaning brush assembly and a wafer cleaning device, aiming to at least solve one of the technical problems existing in the prior art.

[0007] A first aspect of the present invention provides a cleaning brush assembly, comprising: a central shaft and a porous material brush body, the porous material brush body covering the outer surface of the central shaft and forming an integral part thereof, the central shaft having a hollow structure to form a liquid passage through both ends of its length, the shaft wall of the central shaft having a plurality of uniformly distributed liquid outlet holes and a plurality of uniformly distributed elongated grooves, the liquid outlet holes penetrating the shaft wall of the central shaft, the length of the elongated grooves being parallel to the length of the central shaft, the depth of the elongated grooves being less than the thickness of the shaft wall of the central shaft, and at least two liquid outlet holes being provided in the elongated grooves.

[0008] In one embodiment, two liquid outlet holes are located at both ends of the elongated groove.

[0009] In one embodiment, the length direction of the elongated groove is parallel to the axial direction of the central core shaft, and multiple elongated grooves located in the same length direction are arranged at intervals, while elongated grooves located in different length directions are arranged in a staggered manner.

[0010] In one embodiment, the outer surface of the central spindle is further provided with an anti-slip structure for fixing the porous material brush body to prevent the porous material brush body from twisting.

[0011] In one embodiment, the depth of the elongated groove is 1mm to 3mm.

[0012] In one embodiment, the length of the elongated groove is 10mm to 20mm.

[0013] In one embodiment, the central spindle is made of ABS resin.

[0014] In one embodiment, one end of the central mandrel is connected to a liquid inlet mechanism.

[0015] In one embodiment, the other end of the central spindle is connected to a drive mechanism.

[0016] A second aspect of the present invention provides a wafer cleaning apparatus, including a housing, a wafer rotation assembly, and a cleaning brush assembly as described above.

[0017] The beneficial effects of this invention include: multiple elongated grooves are added to the shaft wall of the mandrel, and the interior of each elongated groove has at least two liquid outlet holes communicating with the shaft wall of the mandrel. Cleaning fluid is injected into the mandrel through a liquid inlet mechanism. As the mandrel rotates, the cleaning fluid is discharged through the outlet holes and first flows into the elongated grooves. Only after the elongated grooves are filled with cleaning fluid flowing from the outlet holes does liquid enter the porous material brush body. This enables uniform water discharge along the axial direction of the mandrel, thereby achieving uniform flow of the discharged fluid and ensuring even distribution of the cleaning fluid. The cleaning fluid is placed into elongated grooves at various points along the axis of the central spindle and then ejected to the porous material brush body under centrifugal force. By adding elongated grooves with liquid outlet holes, the flow rate distribution of the cleaning fluid within the central spindle can be effectively adjusted, allowing the cleaning fluid to be discharged evenly along the axis of the central spindle. This avoids uneven flow, which would result in different wetting levels at different points on the porous material brush body and lead to uneven treatment of the wafer during brushing. This improves the consistency of brushing, ensuring uniform force on the wafer during brushing and achieving consistent cleaning, thus optimizing the cleaning effect. Attached Figure Description

[0018] The advantages of the present invention will become clearer and easier to understand through the following detailed description in conjunction with the accompanying drawings, but these drawings are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0019] Figure 1 This invention illustrates a wafer cleaning apparatus according to an embodiment of the present invention;

[0020] Figure 2 and Figure 3 A mandrel provided in an embodiment of the present invention is shown;

[0021] Figure 4 and Figure 5 A mandrel provided in another embodiment of the present invention is shown;

[0022] Figure 6 It shows Figure 5 The anti-slip structure on the central spindle;

[0023] Figure 7 The dimensions of a mandrel provided in one embodiment of the present invention are shown;

[0024] Figures 8 to 10 Cross-sectional views of a mandrel provided in an embodiment of the present invention are shown. Detailed Implementation

[0025] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods and scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein. It should be understood that, unless specifically stated otherwise, for ease of understanding, the following description of specific embodiments of the present invention is based on the premise that the relevant equipment, devices, components, etc., are in their original static state and are not given external control signals or driving forces.

[0026] Furthermore, it should be noted that the terms used in this application to indicate orientation, such as front, back, up, down, left, right, top, bottom, front, back, horizontal, and vertical, are merely for ease of explanation and to aid in the understanding of relative position or direction, and are not intended to limit the orientation of any device or structure.

[0027] To illustrate the technical solution described in this invention, the following description will be provided with reference to the accompanying drawings and embodiments.

[0028] In this application, chemical mechanical polishing is also called chemical mechanical planarization, and wafer is also called wafer, silicon wafer, substrate, etc., with the same meaning and actual function.

[0029] Figure 1 This is a schematic diagram of the structure of a wafer cleaning device 1 provided in an embodiment of the present invention. The wafer cleaning device 1 includes a housing 10, a wafer rotation assembly 20, a cleaning brush assembly 40, and a drive mechanism 30.

[0030] like Figure 1 As shown, in one embodiment of the present invention, the wafer rotation assembly 20 is disposed on the upper part of the base, and the wafer to be cleaned is supported by the wafer rotation assembly 20 and rotates around the axis of the wafer.

[0031] The wafer rotation assembly 20 includes a fixed base, a pair of driving rollers and a driven roller. The driving and driven rollers are equipped with slots for supporting the wafer, and these slots are arranged around the outer periphery of the rollers. The driving and driven rollers are located on the fixed base, and the slots are in the same plane. The driven roller is located in the center of the fixed base, and the driving roller is symmetrically arranged on both sides of the driven roller. The pair of driving and driven rollers are arranged along the outer edge contour of the wafer. The wafer placed in the wafer rotation assembly 20 is limited by the slots, and the outer edge of the wafer is tangent to the bottom surface of the slots. The driving rollers are equipped with drive motors, which drive the driving rollers to rotate. The friction between the outer edge of the wafer and the rollers causes the wafer to rotate around its axis.

[0032] In one embodiment, a speed sensor for detecting wafer rotation speed is provided on the driven roller. The speed sensor can be implemented by a Hall sensor or a photoelectric switch sensor.

[0033] like Figure 1 As shown, in one embodiment of the present invention, the wafer cleaning apparatus 1 is provided with two sets of cleaning brush assemblies 40, respectively disposed on both sides of the wafer to be cleaned, which can roll around their own axis to contact the surface of the wafer to be cleaned for brushing. During the cleaning process, the spray assembly in the housing 10 sprays a large amount of deionized water and / or cleaning solution onto the wafer surface. The cleaning brush assembly 40 can absorb a large amount of cleaning solution used to brush the wafer surface. The rolling cleaning brush assembly 40 contacts the rotating wafer to remove contaminants from the wafer surface. The cleaning brush assemblies 40 located on both sides of the wafer can move horizontally to move away from or towards the wafer. When the cleaning brush assembly 40 moves away from the wafer, a certain gap is maintained between the cleaning brush assembly 40 and the wafer, and the wafer handling robot can grip the wafer to remove the cleaned wafer; when the cleaning brush assembly 40 moves towards the wafer, the cleaning brush assembly 40 abuts against the wafer and performs cleaning of the wafer surface in a contact manner.

[0034] like Figure 1 As shown, the drive mechanism 30 is used to drive two cleaning brush assemblies 40 to move towards each other and clamp the wafer at a certain angle for rolling cleaning. The drive mechanism 30 includes a cleaning brush support assembly and a cleaning brush moving assembly.

[0035] A cleaning brush support assembly is used to support two cleaning brush assemblies 40 located on both sides of the wafer to be cleaned.

[0036] A cleaning brush moving assembly is connected to a cleaning brush support assembly to drive the cleaning brush support assembly and the cleaning brush assembly 40 thereon to move as a whole. The cleaning brush moving assembly includes a guide rail, a lead screw, and a driving component. The guide rail and lead screw are respectively connected to the cleaning brush support assembly so that the cleaning brush support assembly moves along the guide rail under the drive of the lead screw. The driving component is located at the end of the lead screw and drives the lead screw to move, thereby moving the cleaning brush support assembly and the cleaning brush assembly 40 as a whole, so that both ends of the cleaning brush assembly 40 simultaneously contact or move away from the wafer. Furthermore, lead screws are respectively provided at both ends of the cleaning brush assembly 40, thereby allowing for independent adjustment of the movement distance at each end of the cleaning brush assembly 40.

[0037] Combination Figure 1 Briefly describe the wafer cleaning process:

[0038] First, the robotic arm places the wafer to be cleaned into the wafer rotation assembly 20. At this time, a certain distance is reserved between the cleaning brush assembly 40 and the side of the wafer to provide working space for the robotic arm. Under the action of friction, the wafer rotation assembly 20 drives the wafer to rotate around its axis.

[0039] Next, a fluid jetting device (not shown) jets a cleaning solution, such as an acidic or alkaline cleaning solution, toward the rotating wafer.

[0040] Next, the cleaning brush assembly 40 rolls around its axis and moves toward the wafer, so that the cleaning brush assembly 40 comes into contact with the surface of the wafer; the cleaning brush assembly 40 rolls and brushes the surface of the wafer to remove contaminants from the wafer surface, thereby achieving surface cleaning of the wafer.

[0041] After the wafer is cleaned, the cleaning brush assembly 40 moves toward the outside of the wafer, and the cleaning brush 30 separates from the surface of the wafer.

[0042] Next, a fluid jetting device (not shown) continues to spray cleaning fluid toward the rotating wafer. After a period of time, the robotic arm transfers the cleaned wafer to the next process.

[0043] An embodiment of the present invention provides a cleaning brush assembly 40, which includes a central core shaft 41 and a porous material brush body 42, wherein the porous material brush body 42 covers the outer surface of the central core shaft 41 and forms an integral part thereof.

[0044] The porous material brush body 42 has a cylindrical structure and is made of a porous material with good water absorption, such as polyvinyl alcohol (PVA). The porous material brush body 42 may also include other and / or different materials and may exhibit other and / or different material properties. The porous material brush body 42 softens after being filled with liquid, allowing it to brush the wafer. Therefore, it is essential to keep the porous material brush body 42 in a liquid-filled state during the cleaning process and to ensure uniform wetting of the porous material brush body 42. The porous material brush body 42 includes an outer surface, which can be shaped. For example, the outer surface of the porous material brush body 42 may include raised surface features such as nodules. Alternatively, in other embodiments, the outer surface of the porous material brush body 42 may include a smooth geometry.

[0045] The central mandrel 41 is made of ABS resin. ABS refers to acrylonitrile-butadiene-styrene copolymer, a thermoplastic polymer material with high strength, good toughness, and easy processing. The central mandrel 41 is made of ABS resin, which has low water absorption, reducing liquid loss, and the material has good stability, unaffected by water, alkalis, and many acids.

[0046] like Figure 2 and Figure 3 As shown, the outer surface end of the mandrel 41 is provided with a positioning protrusion 43 along the circumferential direction to ensure that when the porous material brush 42 is installed on the outer surface of the mandrel 41, the porous material brush 42 will not extend through the positioning protrusion 43, and to prevent the porous material brush 42 from moving axially and detaching from the mandrel 41 during operation.

[0047] like Figure 3 As shown, in one embodiment, the central core 41 has a hollow structure to form liquid-passing channels extending through both ends of its length, through which liquid flows in. During the wafer cleaning process, liquid flows through the liquid-passing channels from time to time, thereby ensuring that the porous material brush 42 remains wetted.

[0048] One end of the central spindle 41 is connected to the liquid inlet mechanism, and the other end is connected to the drive mechanism. The liquid inlet mechanism has a liquid inlet that communicates with a liquid passage inside the central spindle 41. The liquid inlet mechanism continuously injects cleaning fluid into the central spindle 41 to provide cleaning fluid to the porous material brush body 42, keeping the porous material brush body 42 moist. The drive mechanism is used to rotate the central spindle 41.

[0049] like Figure 7As shown, the external dimensions of the mandrel 41 are: outer diameter A ranging from 30mm to 40mm, and length L ranging from 300mm to 400mm. This externally sized mandrel 41 is specifically designed for cleaning 12-inch wafers. Currently, there are no unified standards for the appearance, dimensions, and materials of the mandrel 41 in the cleaning brush market. This embodiment mainly standardizes the appearance, dimensions, and materials of the mandrel 41 in the cleaning brush assembly 40. For example... Figure 9 As shown, the inner diameter C of the central spindle 41 ranges from 15mm to 20mm.

[0050] like Figures 2 to 5 As shown, the shaft wall of the central mandrel 41 has multiple evenly distributed liquid outlet holes 44, which penetrate the shaft wall of the central mandrel 41 and connect the outer and inner surfaces of the central mandrel 41. During the wafer cleaning process, as the drive mechanism drives the central mandrel 41 to rotate, the liquid flowing into the internal liquid passage of the central mandrel 41 can be discharged outward through the liquid outlet holes 44 under centrifugal force, thus entering the porous material brush body 42. There, the liquid is absorbed by the porous material brush body 42, causing it to wet and soften. The softened porous material brush body 42 can then be used to clean the wafer surface.

[0051] Because the liquid inlet mechanism is only located at one end of the central spindle 41, and the central spindle 41 is relatively long, the liquid flowing into the central spindle 41 will exhibit uneven flow and distribution. Specifically, when a small flow rate of liquid enters through the liquid inlet mechanism, the liquid output is largest at the end of the central spindle 41 closest to the liquid inlet mechanism, gradually decreasing along the axial direction until there is no liquid output at the farthest end. When a medium flow rate of liquid enters through the liquid inlet mechanism, the liquid output is larger in the middle region of the central spindle 41, with smaller flow rates at both ends. When a large flow rate of liquid enters through the liquid inlet mechanism, there is no liquid output at the end of the central spindle 41 closest to the liquid inlet mechanism, and the liquid output gradually increases along the axial direction, reaching its largest output at the farthest end. Therefore, regardless of the flow rate of the cleaning liquid, a uniform liquid distribution cannot be achieved.

[0052] In order to at least solve the above-mentioned technical problems, such as Figures 2 to 5 As shown, in one embodiment of the present invention, the shaft wall of the central mandrel 41 also has a plurality of uniformly distributed elongated grooves 45. The length direction of the elongated grooves 45 is parallel to the length direction of the central mandrel 41. The depth of the elongated grooves 45 is less than the thickness of the shaft wall of the central mandrel 41. The elongated grooves 45 do not penetrate the shaft wall of the central mandrel 41. At least two liquid outlet holes 44 are provided in the elongated grooves 45.

[0053] like Figures 2 to 5As shown, the length direction of the elongated grooves 45 is parallel to the axial direction of the central spindle 41. Multiple elongated grooves 45 located in the same length direction are arranged at intervals, that is, the elongated grooves 45 in the same row are arranged at intervals; the elongated grooves 45 located in different length directions are arranged in a staggered manner, that is, the elongated grooves 45 in different rows are arranged in a staggered manner, located in different circumferential directions. This arrangement improves the uniformity of liquid discharge. The elongated grooves 45 are arranged in different circumferential directions, which can make all parts of the porous material brush body 42 uniformly wetted. In addition, the shaft wall of the central spindle 41 is also provided with liquid outlet holes 44 that are connected inside and outside. Some liquid outlet holes 44 are located inside the elongated grooves 45, and some liquid outlet holes 44 are located between the elongated grooves 45, so that the liquid outlet holes 44 are evenly distributed on the shaft wall of the central spindle 41.

[0054] In this embodiment, multiple elongated grooves 45 are added to the shaft wall of the central spindle 41. The interior of the elongated grooves 45 also has at least two liquid outlet holes 44 that connect to the shaft wall of the central spindle 41. Cleaning liquid is injected into the central spindle 41 through the liquid inlet mechanism. As the central spindle 41 rotates, the cleaning liquid is discharged through the liquid outlet holes 44 and first flows into the elongated grooves 45. Only after the cleaning liquid flowing into the elongated grooves 45 from the liquid outlet holes 44 fills the elongated grooves 45 can liquid enter the porous material brush body 42. This enables uniform water discharge from the central spindle 41 along the axial direction, thereby achieving uniform flow of the discharged liquid. The cleaning liquid can be evenly distributed into the elongated grooves 45 at all points along the axial direction of the central spindle 41, and then thrown out to the porous material brush body 42 under the action of centrifugal force. By adding an elongated groove 45 with a liquid outlet 44, the flow rate distribution of the cleaning fluid within the central spindle 41 can be effectively adjusted. This allows the cleaning fluid to be discharged evenly along the axial direction of the central spindle 41, preventing uneven flow that could lead to varying degrees of wetting on the porous material brush 42 and resulting in uneven stress on the wafer during brushing. This embodiment improves the consistency of brushing, ensuring uniform force on the wafer during brushing, achieving consistent cleaning, and optimizing the cleaning effect.

[0055] In addition, the outer surface of the mandrel 41 is provided with elongated grooves 45, which allow the inner surface of the elastic porous material brush body 42 to be embedded in these elongated grooves 45 after foaming. This increases the contact area between the mandrel 41 and the porous material brush body 42, resulting in high friction when the outer surface of the mandrel 41 contacts the porous material brush body 42. This prevents slippage between the porous material brush body 42 and the mandrel 41, achieving an anti-rotation effect between the porous material brush body 42 and the mandrel 41. This also prevents the porous material brush body 42 from axially twisting when brushing the wafer, keeping the torque stable.

[0056] Furthermore, in one embodiment, the two liquid outlet holes 44 are distributed at both ends of the elongated groove 45, which facilitates the filling of the elongated groove 45 with liquid before overflowing, improving the uniform flow distribution effect achievable by the elongated groove 45. This greatly enhances the uniformity of the cleaning liquid distribution on the porous material brush body 42, ensuring that all parts of the porous material brush body 42 are wetted with cleaning liquid. This embodiment can also significantly increase the water output rate of the central spindle 41, achieving maximum cleaning effect under limited flow conditions.

[0057] Figure 8 A cross-sectional view along the circumference of the central core shaft 41 is shown at the location of the liquid outlet 44, wherein the inner diameter B of the liquid outlet 44 is 1 mm to 2 mm.

[0058] Figure 10 A cross-sectional view along the central core shaft 41 is shown at the location of the elongated groove 45. The length D of the elongated groove 45 is 10mm to 20mm, and the depth E of the elongated groove 45 is 1mm to 3mm.

[0059] Furthermore, based on the structure of the central mandrel 41 provided by this invention, preferably, the central mandrel 41 can be designed as a gradually expanding structure, that is, the inner diameter of the central mandrel 41 gradually decreases along the direction from the end near the liquid inlet mechanism to the end away from the liquid inlet mechanism. In other words, the inner diameter of the central mandrel 41 at the end near the liquid inlet mechanism is larger, while the inner diameter of the central mandrel 41 at the end away from the liquid inlet mechanism is smaller. The inner surface of the central mandrel 41 extends smoothly, that is, the cross-section of the central mandrel 41 along the axial direction is trapezoidal, and the included angle between the extensions of its two long sides is an acute angle. For the cleaning fluid flow with a relatively low inlet flow rate, since the inner diameter of the central mandrel 41 gradually decreases, under the same inlet pressure, the cleaning fluid flow rate in the small inner diameter region will be further increased, so that the cleaning fluid also has a high and stable flow rate in the region of the central mandrel 41 away from the liquid inlet mechanism, further ensuring that the cleaning fluid can flow through the farthest end of the central mandrel 41.

[0060] In one embodiment, the outer surface of the mandrel 41 is further provided with an anti-slip structure 46 for fixing the porous material brush body 42 and preventing the porous material brush body 42 from twisting. The anti-slip structure 46 may be an annular protrusion along the outer periphery of the end of the mandrel 41 to increase the friction between the mandrel 41 and the porous material brush body 42. Furthermore, at least two annular protrusions are provided, located at the left and right ends of the mandrel 41 respectively. Further, the surface of the annular protrusions has a serrated feature to further increase the friction between the mandrel 41 and the porous material brush body 42, preventing the porous material brush body 42 from twisting during wafer cleaning.

[0061] Accordingly, the inner surface of the porous material brush body 42 may include features such as protrusions, knurling, grooves, rough surfaces, etc. These features generate high friction when the inner surface of the porous material brush body 42 contacts the central spindle 41, thereby preventing slippage between the porous material brush body 42 and the central spindle 41, avoiding axial torsion of the porous material brush body 42 during wafer brushing, and keeping the torque stable. The inner surface of the porous material brush body 42 may include additional and / or other features.

[0062] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cleaning brush assembly, characterized in that, include: A central shaft and a porous material brush body are provided. The porous material brush body covers the outer surface of the central shaft and forms a single unit. The central shaft has a hollow structure to form a liquid passage through both ends of its length. The shaft wall of the central shaft has multiple evenly distributed liquid outlet holes and multiple evenly distributed elongated grooves. The liquid outlet holes penetrate the shaft wall of the central shaft. The length of the elongated grooves is parallel to the length of the central shaft. The depth of the elongated grooves is less than the thickness of the shaft wall of the central shaft. At least two liquid outlet holes are provided in each elongated groove. The two liquid outlet holes are distributed at both ends of the elongated grooves. The length direction of the elongated grooves is parallel to the axial direction of the central shaft. Multiple elongated grooves located in the same length direction are arranged alternately, and elongated grooves located in different length directions are arranged in a staggered manner. The outer surface of the central mandrel is also provided with an anti-slip structure to fix the porous material brush body and prevent the porous material brush body from twisting. The anti-slip structure is an annular protrusion along the outer periphery of the end of the central mandrel. At least two annular protrusions are provided, located at both ends of the central mandrel respectively. The surface of the annular protrusion has a serrated feature. The elongated groove is used to accommodate the cleaning liquid discharged from the liquid outlet. After the cleaning liquid fills the elongated groove, it overflows evenly into the porous material brush body. The inner surface of the porous material brush body is embedded in the elongated groove, forming an anti-rotation fit with the central mandrel. The inner diameter of the central mandrel gradually decreases from the liquid inlet end to the liquid outlet end. The inner surface of the central mandrel extends smoothly. The cross-section of the central mandrel along the axial direction is trapezoidal, and the included angle between the extensions of its two long sides is an acute angle.

2. The cleaning brush assembly as described in claim 1, characterized in that, The depth of the elongated groove is 1mm to 3mm.

3. The cleaning brush assembly as described in claim 1, characterized in that, The length of the elongated groove is 10mm to 20mm.

4. The cleaning brush assembly as described in claim 1, characterized in that, The central spindle is made of ABS resin.

5. The cleaning brush assembly as described in claim 1, characterized in that, One end of the central mandrel is connected to the liquid inlet mechanism.

6. The cleaning brush assembly as described in claim 5, characterized in that, The other end of the central spindle is connected to the drive mechanism.

7. A wafer cleaning apparatus, characterized in that, It includes a housing, a wafer rotation assembly, and a cleaning brush assembly as described in any one of claims 1 to 6.

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