A method for integrally forming a PVA wafer brush and an integrally formed wafer brush prepared thereby

Abstract

The application discloses a kind of PVA wafer brush integrated forming method and preparation integrated forming wafer brush, belong to semiconductor cleaning consumable manufacturing technical field.The method includes: to the surface of supporting core pole processing groove and the anchoring structure such as pretreatment, place in foaming mould;Polyvinyl alcohol (PVA) reaction original liquid in situ foaming is injected, and PVA is formed mechanical and micro seamless integrated combination with core pole in crosslinking solidification.Meanwhile, at least one fluid main channel of height direction longitudinal complete penetration is defined in the back of forming cotton body using mould, the back is divided into left and right cloth hole area, and the overall number is reduced by 30%-50%, and the main channel is scattered with auxiliary positioning convex point.The present application combines complicated procedures, so that the production yield is greatly improved to more than 95%, eliminates the back liquid replacement dead zone, so that the physical stability and cleaning liquid replacement performance are improved by more than 30% in all directions, and has very high industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor wafer cleaning consumables and precision brush roller manufacturing technology. Specifically, it relates to an in-situ foaming molding method for an integral cotton body and core rod of a polyvinyl alcohol (PVA) wafer cleaning brush, and an integrally molded wafer brush product with optimized back fluid distribution structure and low bump density prepared by the method. Background Technology

[0002] In semiconductor integrated circuit manufacturing, chemical mechanical polishing (CMP) is a key process for achieving global planarization of the wafer surface. However, CMP leaves a large number of nanoscale abrasive particles, metal ions, organic chemical residues, and slurry contaminants on the wafer surface. If these contaminants are not removed promptly and thoroughly, they will directly lead to fatal defects such as short circuits and leakage currents, severely impacting wafer yield. Therefore, post-CMP cleaning plays an extremely important role in modern semiconductor manufacturing.

[0003] In the post-CMP cleaning process, high-purity polyvinyl alcohol (PVA) wafer brushes are widely used as core contact cleaning consumables for brushing wafer surfaces. A PVA wafer brush typically consists of a core that provides rigid support and fluid distribution, and a PVA porous foam body with high porosity and excellent water absorption elasticity surrounding the core. The cleaning uniformity, batch consistency, operational stability, and fluid replacement efficiency of the wafer brush directly determine the cleaning effect on the wafer surface and the chip yield.

[0004] However, existing PVA wafer brushes primarily employ a split manufacturing process. This involves first fabricating the PVA brush tube and plastic core separately using independent molds, and then assembling them together manually or mechanically using adhesives, heat fittings, mechanical clamping, or physical tightening. This traditional split assembly process and structure generally suffers from the following serious drawbacks: 1. Poor interface stability and risk of mechanical delamination: Under harsh conditions such as long-term immersion in strong acid, strong alkali, or oxidizing chemical cleaning solutions, alternating rotational shear forces, and high-frequency operation, the split brush roller is prone to localized aging, adhesive layer dissolution, or mechanical loosening at the interface between the cotton body and the core rod. Once relative misalignment, coaxiality disruption, or localized delamination occurs, it will lead to uneven stress on the wafer surface, or even directly scratch the wafer surface, causing the wafer to be scrapped.

[0005] 2. Complex process and low yield: The assembly of separate parts requires multiple pre-treatment, gluing, precision fitting, correction and curing assembly processes. Not only is the production cycle long, but human assembly errors are also large. The overall production yield is usually difficult to maintain at a high level, and the consistency of the products is poor.

[0006] 3. Inadequate brush back structure design leads to dead zones during fluid exchange: Traditional brushes often employ a dense, "all-over" bump design on the back to ensure stable installation. The extremely narrow gaps between adjacent bumps create significant localized flow resistance for the cleaning medium (such as deionized water, surfactants, or chemical solutions) as it flows through these gaps, easily forming fluid stagnation zones or dead zones for fluid exchange. This prevents the timely replacement of old reaction residue with newly injected cleaning fluid, severely impacting cleaning uniformity and the efficiency of chemical action. It also increases unnecessary material consumption and mold manufacturing costs.

[0007] In summary, the semiconductor wafer cleaning field urgently needs a new PVA wafer brush manufacturing technology and structural solution that can achieve ultra-high interfacial bonding strength between the cotton body and the core rod, significantly optimize the back-side hydrodynamic characteristics, improve fluid exchange efficiency, and reduce manufacturing costs. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing split-type PVA wafer brushes, such as cumbersome manufacturing processes, easy interface peeling and aging, and the high flow resistance, low fluid exchange efficiency, and fluid dead zones caused by the densely packed bumps on the back of the traditional brush body. This invention provides a method for integrally molding a PVA wafer brush and the resulting integrally molded wafer brush. By employing an "in-situ foaming and integral molding" process, this invention directly foams and molds the PVA cotton material in situ around the pre-treated core rod, creating a seamless, continuous interface both microscopically and macroscopically. Simultaneously, through mold structure design, the molded PVA cotton body is endowed with a novel low bump density and a longitudinally penetrating fluid main channel structure on its back, comprehensively improving the structural stability, production yield, and fluid exchange efficiency of the wafer brush.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A method for integral molding of a PVA wafer brush includes the following steps: S1: Core rod surface pretreatment: Provide a core rod as a wafer brush support skeleton, and perform one or more mechanical combination features such as roughening, grooving or drilling on the outer peripheral surface of the core rod to form a preset matrix anchoring structure. S2: Integrated Foaming Molding: The pre-treated core rod is placed in the central cavity of the foaming mold. Polyvinyl alcohol (PVA) foaming reaction solution is injected into the mold for in-situ foaming molding. During the foaming expansion process, the PVA material directly coats the outer periphery of the core rod and embeds itself into the matrix anchoring structure. After cross-linking and curing, a porous elastic cotton body is formed on the outer periphery of the core rod. Simultaneously, under the constraint of the mold cavity, a raised structure with a specific fluid distribution path is integrally formed on the back of the porous elastic cotton body, resulting in an integrated brush roller blank; and S3: Post-molding processing: Demold the integrated brush roller blank and perform curing, cleaning, shaping, drying, trimming and sizing to obtain an integrated PVA wafer brush; In step S2, the back structure of the porous elastic cotton body defined by the mold cavity is provided with at least one fluid main channel extending longitudinally along the height direction of the brush body. The fluid main channel divides the back of the porous elastic cotton body into multiple pore areas. Multiple protrusion structures are distributed non-fully in the pore areas, thereby reducing the overall distribution density of protrusions on the back of the porous elastic cotton body.

[0010] In some embodiments, in step S1, the material of the core rod is selected from any one of PET-P, CPVC, PEEK or PRF; after mechanical bonding feature processing, the outer peripheral surface of the core rod is subjected to one or more chemical pretreatments, such as surface activation, coupling agent treatment or base coating treatment.

[0011] In some embodiments, in step S2, the main fluid channel extends continuously from the top to the bottom of the porous elastic cotton body, and the width of the main fluid channel is 3-5 times the center-to-center distance between adjacent protrusion structures.

[0012] In some embodiments, the width of the main fluid channel ranges from 26mm to 55mm; adjacent protrusion structures within each of the perforation areas are arranged in a square orthogonal column, and the center-to-center distance between adjacent protrusion structures is 10mm to 11mm.

[0013] In some embodiments, in step S2, the cavity of the foaming mold defines a number of discontinuous and scattered auxiliary positioning protrusions on the surface corresponding to the main fluid channel.

[0014] This invention also provides an integrally molded PVA wafer brush, manufactured using the aforementioned integral molding method. The PVA wafer brush includes a core rod and a PVA porous elastic cotton body integrally molded and wrapped around the core rod through in-situ foaming. The back of the PVA porous elastic cotton body is provided with multiple protrusion structures for mechanically engaging with the base or fluid distribution plate of a cleaning device. The invention is characterized by: at least one longitudinally extending fluid main channel along the brush body height direction being provided on the back of the PVA porous elastic cotton body, dividing the back of the brush body into a left-side perforation area and a right-side perforation area; multiple protrusion structures are distributed within the left-side and right-side perforation areas, and the overall number of protrusion structures is reduced by 30%-50% compared to a full-coverage design; the fluid main channel also contains several scattered, discontinuously distributed auxiliary positioning protrusions.

[0015] In some embodiments, the protrusion structures in the left and right perforation areas are arranged in a square, orthogonal row, the center-to-center distance between adjacent protrusion structures is 10mm-11mm, and the width of the main fluid channel is 26mm-55mm.

[0016] In some embodiments, the two sides of the main fluid channel are directly connected to the left and right orifice areas, forming a low-resistance fluid distribution network that rapidly diffuses from the main fluid channel to the two orifice areas.

[0017] In some embodiments, the outer peripheral surface of the core rod has a matrix anchoring structure consisting of one or more of roughened textures, circumferential grooves, axial grooves, or blind holes. The inner peripheral surface of the PVA porous elastic cotton and the outer peripheral surface of the core rod form a continuous micro-interface with mutual mechanical interlocking and intertwined microscopic molecular chains during the foaming cross-linking and curing process.

[0018] In some embodiments, the PVA wafer brush is suitable for post-CMP chemical mechanical cleaning equipment for 8-inch or 12-inch semiconductor wafers.

[0019] Compared with existing technologies, this invention provides an intelligent sweeping robot cleaning system based on PVA material, which has the following beneficial effects: 1. Significantly simplified production process and dramatically increased production yield: This invention combines and simplifies the traditional, cumbersome, and separate manufacturing processes of PVA cotton body foaming, rod making, pretreatment, adhesive application and assembly, and heat fitting into a single "in-situ foaming and molding" process, greatly shortening the process chain. Batch verification on the production line has significantly improved the overall product yield from the lower levels of traditional processes to over 95%.

[0020] 2. Comprehensive Improvement in Structural Stability and Safety: By eliminating traditional adhesive bonding or physical bonding interfaces, in-situ foaming allows PVA to tightly integrate with the macroscopic anchoring characteristics of the core rod surface at the moment of cross-linking and molding, and to form chain entanglements with microscopic chemical functional groups, creating a highly continuous and stable interface. This results in an overall improvement of over 30% in the shear strength, peel resistance, and coaxiality physical stability between the cotton body and the core rod, completely eliminating the risk of delamination.

[0021] 3. Significantly improved fluid replacement efficiency and complete elimination of fluid dead zones: By innovatively opening a fully vertically continuous fluid main channel and reducing the number of bumps by 30%-50%, actual operation tests show that the replacement rate and fluid replacement efficiency of the back cleaning medium are improved by more than 30%, and the overall comprehensive performance of wafer cleaning is improved by more than 30%.

[0022] 4. Reduced material consumption and costs: The reduction in the number of protrusions on the back of the brush body reduces PVA material consumption and simplifies the back structure of the foaming mold, thereby reducing mass production costs.

[0023] 5. Excellent assembly stability and flatness: While significantly reducing the density of protrusions, scattered auxiliary positioning protrusions are retained in the main fluid channel, which does not affect fluid flow and ensures assembly flatness. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the integrally molded PVA wafer brush of the present invention; Figure 2 This is a schematic diagram of the bump arrangement of the integrally molded PVA wafer brush of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Fabrication of a monolithic wafer brush based on a PET-P core rod This embodiment provides a high-precision PVA wafer brush suitable for 12-inch wafer cleaning equipment. The core material is PET-P. The specific manufacturing process is as follows: 1. Core rod surface pretreatment: The PET-P core rod is roughened by sandblasting (controlling the surface roughness Ra to 3.2μm-6.3μm), and inverted trapezoidal mechanical blind holes and dovetail grooves with a depth of 1.5mm are uniformly cut along the circumference to form the substrate anchoring structure. Then, ultrasonic cleaning and drying are performed.

[0027] 2. Chemical activation and primer coating: Immerse the core rod in a 1.5wt% silane coupling agent (KH-550) ethanol solution for 5 minutes, then remove and dry at 100℃.

[0028] 3. In-situ foaming and integral molding: The core rod is fixed in a dedicated foaming mold. PVA aqueous solution, crosslinking agent (formaldehyde), catalyst (sulfuric acid), and foaming agent are mixed to prepare the in-situ foaming reaction stock solution, which is then rapidly injected into the mold. The in-situ foaming reaction is maintained for 12 hours at 65℃ and 90% relative humidity. The mold directly defines an axially penetrating main fluid channel (35mm wide) on the back of the molded cotton body, as well as a square linear matrix of raised dots with a center-to-center distance of 10.5mm in the left and right perforation areas (reducing the total number of raised dots by 42%), and retains auxiliary positioning raised dots within the channel.

[0029] 4. Post-molding treatment: After the one-piece molding is completed, the mold is removed and cured at 50°C for 24 hours. It is then rinsed with deionized water under high pressure. Finally, it is precision cut, outer diameter trimmed and end-processed, and then calibrated on a special dynamic balancing tester.

[0030] Example 2: Fabrication of a monolithic wafer brush based on a PEEK core rod and different fluid parameters In this embodiment, the core rod material is switched to polyetheretherketone (PEEK). A mesh-like microporous structure (0.8 mm diameter, 1.2 mm depth) is laser-etched onto its surface. In the foaming mold design, the width of the longitudinally penetrating main fluid channel is set to 50 mm (approximately 4.8 times the center-to-center distance of the protrusions), and the center-to-center distance of the protrusions within the perforation area is finely adjusted to 11 mm. This design reduces the total number of protrusions on the overall back side by 48%.

[0031] Example 3: Example of multi-parameter variation based on CPVC core rod In this embodiment, economical chlorinated polyvinyl chloride (CPVC) is selected as the support core rod. An axially long groove is machined on the surface of the core rod, combined with through holes. During the foaming process, the width of the main fluid channel is set to 28mm, and the center-to-center spacing of the protrusions is designed to be 10mm. With this structure, the total number of protrusions on the back is reduced by approximately 32%.

[0032] To quantitatively verify the beneficial effects of the integrally molded PVA wafer brush described in this invention, a standard industrial-grade production line simulation test platform was established. The performance indicators of Examples 1 to 3 and the conventional comparative components described below were all measured based on the following standardized test methods and procedures: I. Comprehensive Production and Processing Yield Testing 1.1 Test Sample Size Each group (including Example 1, Example 2, Example 3, and the conventional split assembly comparison piece) continuously produces 1000 wafer brush blanks as the statistical base.

[0033] 1.2 Testing Process and Judgment Criteria After the demolding and post-forming processing are completed, the geometric dimensions of all finished wafer brushes are fully inspected using a high-precision optical image measuring instrument and a three-axis coordinate measuring machine (CMM). The criteria for determining a finished product as defective include: (1) The overall coaxiality runout error of the wafer brush is greater than 0.15mm; (2) The surface or back of the PVA elastic cotton body has visible minor defects, or the pore diameter is greater than 0.5 mm due to uneven pore size. (3) Small gaps, slippage, or local delamination occur at the joint between the cotton body and the end of the internal support core rod.

[0034] Finally, the overall production yield of each group was calculated by dividing the number of qualified parts by the total number of produced parts (1000 pieces).

[0035] II. Interfacial Peel Resistance and Shear Strength Stability Test 2.1 Axial peel strength test Quantitative testing was performed using a universal electronic tensile testing machine. During testing, the bottom end of the rigid support core rod of the wafer brush was fixed in the lower chuck of the testing machine, and the upper end of the external PVA porous elastic cotton body was firmly clamped using a special circumferential cavity clamp. The testing machine was started, and a constant tensile speed of 50 mm / min was set for axial tension until the PVA porous elastic cotton body completely peeled off from the surface of the core rod or the cotton body itself tore. The maximum axial load value (unit: Newtons, N) during the failure process was recorded.

[0036] 2.2 Rotational shear torque test The wafer brush sample was completely immersed in a 1.5 wt% hydrogen peroxide (H2O2) strong oxidizing chemical cleaning solution for 72 hours at 40°C for accelerated aging. Subsequently, the wafer brush was mounted on a simulated spindle, and a constant radial pressure of 20 kPa was applied to its outer circumference to ensure tight contact with the damping friction plate. The spindle was started and subjected to a high-speed alternating rotation test at 1500 rpm, with torque changes monitored in real time using a miniature torque sensor connected to the spindle. When a sudden change in rotational speed and torque was detected, i.e., relative slippage occurred between the brush body and the support core rod, the ultimate shear torque value at that moment was recorded. The final data was characterized as the percentage increase in average failure load compared to a conventional comparative sample.

[0037] III. Fluid resistance to dead zone area ratio test 3.1 Test Principles and Instruments The method combines dynamic fluorescence staining tracing with machine vision image analysis. The testing equipment includes a 12-inch wafer cleaning machine fluid distribution base, a high-resolution industrial camera, and a 465nm ultraviolet excitation source.

[0038] 3.2 Testing Process (1) Initial staining: Assemble the wafer brush sample onto the fluid distribution plate of the cleaning equipment according to the standard operating procedure. First, inject a high concentration of blue fluorescein sodium aqueous solution into the fluid channel until the fluorescent solution completely fills the gaps between the bumps and the flow channel network on the back of the wafer brush.

[0039] (2) Dynamic replacement: Start the main shaft of the equipment to rotate at a speed of 1200 rpm, and at the same time switch the fluid input source to continuously inject high-purity deionized water into the distribution plate at a constant flow rate of 500 ml / min for rinsing and replacement.

[0040] (3) Image capture and ratio calculation: At 3, 5, and 10 seconds after the rinsing process begins, high-speed industrial cameras are used to capture real-time images of the fluorescence distribution on the back of the wafer brush under ultraviolet excitation. The images are then imported into image processing software (Image-Pro Plus) to extract pixels in the blue region at specific wavelengths. Since the fluorescence in the smooth rinsing area is quickly washed away, the area with residual fluorescence represents the "fluid dead zone" where the old and new fluids cannot be replaced due to excessive local flow resistance. The percentage of the area of ​​the blue fluorescence residue region relative to the total area of ​​the back of the wafer brush is calculated to obtain the fluid resistance to dead zone area ratio.

[0041] IV. Backside electrolyte replacement efficiency and overall performance testing of wafer surface cleaning 4.1 Back-side fluid replacement efficiency test A miniature conductivity sensor was installed online in the downstream outlet pipe of the cleaning channel. When the system switched from running a high-concentration chemical cleaning solution (initial conductivity approximately 150 mS / cm) to injecting pure deionized water for cleaning, the total response time required for the outlet conductivity to rapidly decrease from its peak value and stabilize to a reference value (less than 1 μS / cm) was recorded. The shorter the replacement time, the higher the fluid topology network on the back of the wafer brush in terms of fluid exchange efficiency.

[0042] 4.2 Comprehensive performance test of wafer surface cleaning (defect rate reduction) (1) Preparation of contaminated silicon wafers: 12-inch high-purity silicon dioxide epitaxial wafers that have undergone standard chemical mechanical polishing (CMP) process are selected. Nanoscale silicon dioxide abrasive particles, trace amounts of iron / copper metal ions and specific slurry organic contaminants are deliberately manufactured and left on the surface of the wafers as standard contamination source silicon wafers.

[0043] (2) Brushing and Cleaning: The initial total number of defects on the surface of the contaminated silicon wafer was pre-read using a wafer surface defect detector (KLA-Tencor SP series). Subsequently, brushing tests were performed using the wafer brushes prepared in Examples 1 to 3 and conventional control wafers, respectively. The process parameters were set as follows: spindle speed 1200 rpm, cleaning fluid flow rate 500 ml / min, and double-sided precision brushing time 45 seconds.

[0044] (3) Defect Rate Calculation: After brushing, the wafer is dried at high speed and then the entire surface of the wafer is scanned again using a defect detector. The number of residual particles with a diameter greater than 45nm, the number of surface scratches, and the total number of metal contamination points are counted. The defect reduction rate is calculated using the formula: the defect reduction rate equals (the number of wafer defects after brushing of the traditional comparison device minus the number of wafer defects after brushing of the present invention) divided by the number of wafer defects after brushing of the traditional comparison device, and converted into a percentage. This indicator is used to quantitatively evaluate the improvement in the overall performance of wafer brush cleaning.

[0045] The test results are as follows: In summary, this invention addresses two long-standing industry pain points in the semiconductor Post-CMP cleaning consumables field: "easy interface peeling and aging" and "dead zones in back-side fluid replacement." It breaks through the limitations of the traditional "split manufacturing + subsequent adhesive coating and assembly" process, creatively proposing an in-situ foaming integrated molding technology, and combining it with a topological structure of low-density bumps and longitudinally penetrating fluid main channels, achieving a comprehensive leap from manufacturing process to final cleaning performance.

[0046] I. Core Breakthrough at the Technological Level: From "Cumbersome Assembly" to "One-Shot Molding" Traditional process drawbacks: The split-type process involves more than ten steps, including processing the plastic core rod, separately foaming the PVA cotton tube, applying adhesive to the surface, manual or mechanical splicing, alignment, and curing. Because the adhesive is prone to aging in strong acid and alkali cleaning solutions, it is difficult to control the coaxiality in mass production, and the overall production yield can usually only be maintained at around 82%.

[0047] The beneficial effects of this invention are as follows: By placing the pre-treated (mechanical anchoring + chemical activation) core rod directly into the mold for in-situ foaming, PVA forms a seamless macro- and micro-level bond with the core rod during cross-linking and curing, merging multiple processes into one step. Batch verification shows that the overall production yield has significantly increased to 95.5% ~ 96.8%, greatly shortening the mass production cycle and reducing manufacturing costs.

[0048] II. Fundamental Improvement in Structural Stability: From "Adhesive Bonding" to "Molecular Entanglement" Defects of traditional processes: When traditional brush rollers are subjected to high-speed alternating rotational shearing forces of over 1200 rpm for a long time, as well as immersion in chemical solutions, the adhesive layer is prone to local dissolution or peeling, resulting in the cotton body being off-center, or even scratching high-value wafers.

[0049] The beneficial effects of this invention are as follows: Universal tensile testing and rotational shear torque testing have confirmed that the in-situ foaming process of this invention deeply entangles the microscopic molecular chains of the PVA material with the active functional groups of the core rod, and macroscopically embeds anchoring structures such as dovetail grooves. This results in an overall improvement of interfacial peel resistance and shear strength stability of 31%-38%, and extends the continuous rotation service life from 220 hours to over 310-380 hours, completely eliminating the risks of eccentricity and delamination.

[0050] III. Dimensional Upgrade in Fluid Dynamics: From "High-Drag Cellular Structures" to "Fluid Highways" Traditional process drawbacks: The traditional back side uses densely packed bumps, resulting in extremely high resistance to fluid flow in the tiny gaps. Dynamic fluorescence staining tracer testing shows that the fluid dead zone area ratio is as high as 18.5%, which easily leads to the retention of old residual liquid and waste of chemicals.

[0051] The beneficial effects of this invention are as follows: By creating a fully longitudinally continuous main fluid channel and significantly reducing the total number of protrusions by 30%-50%, this invention constructs a low-resistance network with a "central high-efficiency flow channel and rapid diffusion on both wings." Tests show that its fluid dead zone area ratio drops sharply to below 1.5% (as low as 0.8%), and the back fluid replacement efficiency is improved by 32%-41%, achieving instantaneous renewal of the cleaning solution.

[0052] IV. The concentrated manifestation of ultimate end-user benefits: high cleanliness and low cost of ownership (COO) Defect control: In the actual post-CMP brushing test of 12-inch wafers, the improved solution replacement efficiency eliminated secondary contamination, and the integrated structure ensured excellent stress flatness, ultimately improving the overall performance of wafer surface cleaning (defect rate reduction) by more than 33% (significantly reducing the number of particles larger than 45nm and scratches).

[0053] Economic benefits: The reduction in bump density not only reduces the consumption of high-purity PVA material by about 5%-10%, but also significantly reduces the complexity of back engraving of foaming molds and extends mold life.

[0054] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A method for integral molding of a PVA wafer brush, characterized in that, Includes the following steps: S1: Core rod surface pretreatment: Provide a core rod as a wafer brush support skeleton, and perform one or more mechanical combination features such as roughening, grooving or drilling on the outer peripheral surface of the core rod to form a preset matrix anchoring structure. S2: Foaming Integrated Molding: The pretreated core rod is placed in the central cavity of the foaming molding mold, and polyvinyl alcohol (PVA) foaming reaction solution is injected into the foaming molding mold for in-situ foaming molding. During the foaming expansion process, the PVA material directly covers the outer periphery of the core rod and is embedded in the matrix anchoring structure. After cross-linking and curing, a porous elastic cotton body is formed on the outer periphery of the core rod. The back of the porous elastic cotton body is simultaneously integrally molded with a protrusion structure with a specific fluid distribution path under the limitation of the mold cavity, thus obtaining an integrated brush roller blank. as well as S3: Post-molding processing: Demold the integrated brush roller blank and perform curing, cleaning, shaping, drying, trimming and sizing to obtain an integrated PVA wafer brush; In step S2, the back structure of the porous elastic cotton body defined by the mold cavity is provided with at least one fluid main channel extending longitudinally along the height direction of the brush body. The fluid main channel divides the back of the porous elastic cotton body into multiple pore areas. Multiple protrusion structures are distributed non-fully in the pore areas, thereby reducing the overall distribution density of protrusions on the back of the porous elastic cotton body.

2. The method for integral molding of a PVA wafer brush according to claim 1, characterized in that: In step S1, the core rod is made of any one of PET-P, CPVC, PEEK or PRF. After mechanical bonding processing, the outer peripheral surface of the core rod is subjected to one or more chemical pretreatments, such as surface activation, coupling agent treatment or base coating treatment.

3. The method for integral molding of a PVA wafer brush according to claim 1, characterized in that: In step S2, the main fluid channel extends continuously from the top to the bottom of the porous elastic cotton body, and the width of the main fluid channel is 3-5 times the center-to-center distance between adjacent protrusion structures.

4. The integral molding method for a PVA wafer brush according to claim 1, characterized in that: The width of the main fluid channel ranges from 26mm to 55mm; adjacent protrusion structures within each of the perforation areas are arranged in a square, orthogonal row, and the center-to-center distance between adjacent protrusion structures is 10mm-11mm.

5. The integral molding method for a PVA wafer brush according to claim 1, characterized in that: In step S2, the cavity of the foaming mold defines a number of discontinuous and scattered auxiliary positioning protrusions on the surface corresponding to the main fluid channel.

6. A one-piece molded PVA wafer brush, characterized in that, The PVA wafer brush, manufactured using the integral molding method according to any one of claims 1 to 5, includes a core rod and a PVA porous elastic cotton body integrally molded and wrapped around the core rod through in-situ foaming. The back of the PVA porous elastic cotton body is provided with multiple protrusion structures for mechanically engaging with the base or fluid distribution plate of the cleaning equipment. The brush is characterized by having at least one longitudinally extending and penetrating main fluid channel on the back of the PVA porous elastic cotton body, dividing the back into a left-side perforation area and a right-side perforation area. Multiple protrusion structures are distributed within the left-side and right-side perforation areas, and the total number of protrusion structures is reduced by 30%-50% compared to a full-coverage design. The main fluid channel also contains several scattered, discontinuously distributed auxiliary positioning protrusions.

7. The integrally molded PVA wafer brush according to claim 6, characterized in that: The protrusion structures in the left and right perforation areas are arranged in a square, orthogonal row, with a center-to-center distance of 10mm-11mm between adjacent protrusion structures, and the width of the main fluid channel is 26mm-55mm.

8. The integrally molded PVA wafer brush according to claim 6, characterized in that: The two sides of the main fluid channel are directly connected to the left and right orifice areas, forming a low-resistance fluid distribution network that rapidly diffuses from the main fluid channel to the two orifice areas.

9. The integrally molded PVA wafer brush according to claim 6, characterized in that: The outer peripheral surface of the core rod has a matrix anchoring structure consisting of one or more of the following: roughened texture, circumferential groove, axial groove, or blind hole. During the foaming, cross-linking, and curing process, the inner peripheral surface of the PVA porous elastic cotton body and the outer peripheral surface of the core rod form a continuous micro-interface where they are mechanically interlocked and the microscopic molecular chains are entangled.

10. A one-piece molded PVA wafer brush according to any one of claims 6 to 9, characterized in that: The PVA wafer brush is suitable for post-CMP chemical mechanical cleaning equipment for 8-inch or 12-inch semiconductor wafers.

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