High-performance cmp polishing pad based on polyurethane material and preparation method thereof

Abstract

The application relates to the field of CMP polishing technology and discloses a high-performance CMP polishing pad based on a polyurethane material and a preparation method thereof. The polishing pad adopts a multilayer composite structure including a base pad layer, an elastic buffer pad layer and a polyurethane polishing surface layer. The top of the polishing surface layer is provided with an inner groove and a fine grinding head. The fine grinding heads are arranged in an array to form a drainage groove therebetween. A liquid accumulation groove is arranged at the edge. An inverted V-shaped guide hole is arranged in the side wall of the liquid accumulation groove and extends to the bottom of the inner groove. The bottom plate of the liquid accumulation groove is provided with filter holes and covered filter cloth. The multilayer composite structure provides elastic buffering and pressure uniformity. The fine grinding head array ensures stable polishing contact. The guide hole and the liquid accumulation groove constitute a drainage system, which effectively solves the problem that polishing liquid splashes due to centrifugal force in a traditional open partition groove. The stability and uniformity of the polishing process are improved, and the pollution of the workbench surface and the cleaning and maintenance frequency are reduced.

Description

Technical Field

[0001] This invention relates to the field of CMP polishing technology, and in particular to a high-performance CMP polishing pad based on polyurethane material and its preparation method. Background Technology

[0002] Chemical mechanical polishing (CMP) is a key process for achieving global planarization in modern semiconductor manufacturing and precision optical processing. The polishing pad, as a core component of the CMP system, directly affects the polishing effect and workpiece surface quality. Polyurethane materials are widely used in the preparation of high-performance CMP polishing pads due to their excellent wear resistance, chemical corrosion resistance, elastic recovery, and tunable physical properties. In existing technologies, polyurethane polishing pads typically employ a multi-layer composite structure, including a base layer providing mechanical support, an elastic intermediate layer with buffering properties, and a polyurethane polishing surface layer containing specific grooves or micropores. These structures work together to distribute the polishing fluid, deliver abrasive, and remove debris, achieving efficient and uniform material removal and surface finishing of semiconductor workpieces.

[0003] For example, the patent document with announcement number CN118893568B discloses a CMP polishing pad and its preparation process for improving polishing flatness. The polishing pad includes a hard polishing layer and a soft polishing layer, with an inner pad ring support distributed in a ring array between the two. The soft layer can shrink to assist when the hard layer is under pressure. It can solve the problem of particles generated by friction mixing into the liquid and affecting the polishing accuracy. During the polishing process, the polishing liquid enters the liquid guiding hole, is filtered by the soft layer, and is discharged from the bottom drain channel.

[0004] Regarding the above and existing related technologies, the inventors believe that the following defects often exist: the edge of the trough on the existing polishing pad that is responsible for guiding and conveying the polishing liquid is open. When the polishing pad rotates with the polishing disc, the polishing liquid in the trough will be thrown out from the port at the edge of the pad due to the centrifugal force of rotation, which will cause the polishing liquid to splash, contaminate the worktable of the CMP polishing machine, and increase the cleaning workload. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing polishing pad has an open design at the edge of the groove, which causes the polishing liquid to be thrown and scattered from the edge due to centrifugal force when rotating, thus contaminating the CMP polishing machine table and increasing the amount of cleaning work. To address this, we propose a high-performance CMP polishing pad based on polyurethane material and its preparation method.

[0006] To achieve the above objectives, this application adopts the following technical solution: a high-performance CMP polishing pad based on polyurethane material, comprising a base pad layer and an elastic buffer pad layer pressed and fixed on top of the base pad layer. A polyurethane polishing surface layer is pressed and fixedly connected to the top of the elastic buffer layer. An inner groove is provided on the top of the polyurethane polishing surface layer. Several fine grinding heads are uniformly and fixedly connected to the bottom plate of the inner groove. Adjacent fine grinding heads are evenly arranged to form a crisscrossing and interconnected drainage channel. Several liquid accumulation grooves are uniformly and evenly opened at the top edge of the polyurethane polishing surface layer outside the inner groove. Guide holes are opened on the side wall of each liquid accumulation groove. The other end of each guide hole extends to the bottom of the inner groove. Filter holes are uniformly opened on the bottom plate of the liquid accumulation groove. The filter holes extend through to the bottom of the base pad layer. Filter cloth is laid on the bottom plate of the liquid accumulation groove above the filter holes.

[0007] Preferably, the guide hole has an inverted V-shaped structure, with the two ends of the guide hole tilted downwards toward the inner groove and the bottom plate of the liquid accumulation tank, respectively.

[0008] Preferably, the bottom of the two ends of the guide hole is flush with the bottom edge of the inner groove and the liquid accumulation tank, respectively, and the end of the guide hole near the inner groove is flared.

[0009] Preferably, a number of mounting slots are evenly spaced at the bottom edge of the base pad, and elastic support columns are fixedly connected to the top of the base pad corresponding to the fine grinding head.

[0010] Preferably, the elastic buffer pad has expansion holes that are respectively opened through the elastic support column. When the elastic buffer pad is pressed and fixed to the top of the base pad, the expansion holes are respectively wrapped around the outside of the elastic support column.

[0011] Preferably, the bottom of the polyurethane polished surface layer is provided with an embedded groove corresponding to the elastic support column. The top of the embedded groove extends into the interior of the fine grinding head. When the polyurethane polished surface layer is pressed and fixed on the top of the elastic buffer pad layer, the top of the elastic support column is embedded in the embedded groove.

[0012] Preferably, the liquid collection tank has a U-shaped structure, with the end opening of the liquid collection tank extending to the side wall of the polyurethane polished surface layer, and the bottom plate of the liquid collection tank is set at a height higher than the bottom plate of the inner groove.

[0013] Preferably, an annular notch is provided on the side wall of the polyurethane polished surface layer on the outer side of the liquid accumulation tank port, and a positioning hole is provided on the side wall of the annular notch between adjacent liquid accumulation tanks. An elastic sealing ring is provided on the outer wall of the annular notch, and a positioning pin is fixedly connected to the inner wall of the elastic sealing ring at the corresponding positioning hole, and the positioning pin matches the positioning hole.

[0014] Preferably, the Shore D hardness of the elastic support column is 50-70, the inner diameter of the telescopic air hole is 0.1-0.3mm larger than the outer diameter of the elastic support column, and the depth of the embedded groove is 1 / 3 to 1 / 2 of the height of the precision grinding head.

[0015] Preferably, the present invention provides another technical solution: a high-performance CMP polishing pad based on polyurethane material and its preparation method, comprising the following implementation steps:

[0016] S1. Prefabrication and processing: Prefabricated bodies of a base pad, an elastic buffer pad, and a polyurethane polished surface layer are prepared respectively; wherein, the base pad prefabricated body is integrally formed with an installation groove and an elastic support column, the elastic buffer pad prefabricated body is provided with a telescopic air hole matching the elastic support column, and the polyurethane polished surface layer prefabricated body is formed with an inner groove, a fine grinding head, a drainage groove, a liquid accumulation groove, and an embedded slot at the bottom, and a guide hole connecting the inner groove and the liquid accumulation groove is processed;

[0017] S2. Adhesive application and assembly: Apply adhesive to the interface of each preform, and then align and assemble so that the elastic support column passes through the telescopic air hole, and the top of the elastic support column is inserted into the embedded groove to form an uncured three-layer stacked structure.

[0018] S3, Adhesive Pressing and Curing: Apply pressure to the three-layer laminated structure to press and fix each layer into an integrated composite pad through the adhesive;

[0019] S4. Functional component installation: Filter holes are machined on the bottom plate of the liquid accumulation tank and filter cloth is installed. An elastic sealing ring is installed at the annular notch on the side wall of the polyurethane polishing surface layer to complete the preparation of the polishing pad.

[0020] The technical effects and advantages of this invention are as follows:

[0021] This invention employs a three-layer press-fit structure consisting of a base pad, an elastic buffer pad, and a polyurethane polishing surface layer. Combined with the inner grooves, fine grinding head, crisscrossing drainage channels, and accumulation tanks at the edges of the polyurethane polishing surface layer, a highly efficient polishing slurry distribution and waste liquid guidance system is formed. The inverted V-shaped guide holes on the sidewalls of the accumulation tank smoothly guide the waste liquid from the bottom of the inner grooves into the accumulation tank. The sidewall obstruction and inclined channel design significantly reduce the polishing slurry flow rate, preventing it from splashing from the edges. Simultaneously, the bottom plate of the accumulation tank is equipped with filter holes and a filter cloth, achieving preliminary filtration and orderly downward discharge of the waste liquid, further preventing liquid accumulation and overflow. This effectively solves the problem of existing polishing pads where the open edges of the grooves cause the polishing slurry to scatter and contaminate the work surface due to centrifugal force during high-speed rotation, reducing the cleaning workload for workers. Attached Figure Description

[0022] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0023] Figure 1 This is a schematic diagram of the overall structure of the high-performance CMP polishing pad based on polyurethane material and its preparation method according to the present invention.

[0024] Figure 2 This is an exploded view of the overall structure of the high-performance CMP polishing pad based on polyurethane material and its preparation method according to the present invention.

[0025] Figure 3 This is a schematic cross-sectional view of the polyurethane polishing surface layer of the high-performance CMP polishing pad based on polyurethane material and its preparation method according to the present invention.

[0026] Figure 4 This is a schematic diagram of the assembly structure of the polyurethane polishing surface layer and the elastic sealing ring of the high-performance CMP polishing pad based on polyurethane material and its preparation method of the present invention.

[0027] Figure 5 This invention relates to a high-performance CMP polishing pad based on polyurethane material and its preparation method. Figure 4 Enlarged structural diagram at point A in the middle;

[0028] Figure 6 This is an overall flowchart of the high-performance CMP polishing pad based on polyurethane material and its preparation method according to the present invention.

[0029] In the diagram: 1. Base pad; 11. Mounting groove; 12. Elastic support column; 2. Elastic buffer pad; 21. Expansion vent; 3. Polyurethane polished surface layer; 31. Annular notch; 32. Positioning hole; 4. Inner groove; 5. Grinding head; 51. Embedded slot; 6. Drainage groove; 7. Liquid accumulation groove; 8. Guide hole; 9. Elastic sealing ring; 91. Positioning column. Detailed Implementation

[0030] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0031] Example 1:

[0032] Reference Figure 1-5 As shown, the present invention provides a technical solution: a method based on polyurethane material

[0033] This high-performance CMP polishing pad features a multi-layered composite design. From bottom to top, it comprises a base layer 1, an elastic buffer layer 2, and a polyurethane polishing surface layer 3, all pressed and fixed together. The base layer 1 serves as the supporting foundation for the entire polishing pad and is typically made of high-strength, high-rigidity polyurethane or composite materials to provide sufficient mechanical stability. The elastic buffer layer 2 is attached to the top of the base layer 1 via a pressing mechanism. The elastic buffer layer 2 is primarily composed of polyurethane material with good elastic modulus. Its function is to provide the main elastic buffering function during polishing, absorbing some mechanical stress and ensuring uniform pressure transmission at the polishing interface.

[0034] On top of the elastic buffer layer 2, a polyurethane polishing layer 3 is also connected by a pressing and fixing method. The polyurethane polishing layer 3 is the surface that directly contacts and polishes the wafer, and its material properties and surface structure are crucial to the polishing effect. Polyurethane material has good wear resistance, chemical corrosion resistance and processability, making it very suitable as a polishing layer material.

[0035] To improve polishing performance and waste liquid treatment efficiency, the top of the polyurethane polishing layer 3 features a special structural design. An inner groove 4 is provided on the top of this polyurethane polishing layer 3. This inner groove 4 is typically located in the central area of ​​the polishing pad, and its depth and area can be adjusted according to actual polishing needs. It is mainly used to concentrate the grinding fluid and collect initial waste liquid. Several fine grinding heads 5 are uniformly spaced and fixedly connected to the bottom plate of the inner groove 4. These fine grinding heads 5 can be cylindrical, prismatic, or any other geometric shape. The upper surface of the fine grinding heads 5 is a flat surface, a slightly convex spherical surface, or a grinding surface with micron-level roughness. They serve as the main grinding units, directly contacting the wafer surface. The material of the fine grinding heads 5 is usually the same as that of the polyurethane polishing layer 3, but its hardness, microporous structure, etc., can be optimized to provide better grinding performance. Adjacent fine grinding heads 5 are uniformly arranged to form crisscrossing and interconnected drainage channels 6. The function of the drainage channel 6 is to guide the flow of polishing slurry on the polyurethane polishing surface layer 3, transporting fresh polishing slurry to the polishing area while simultaneously draining waste slurry carrying grinding debris from the polishing area. This crisscrossing layout ensures uniform wetting of the polishing slurry and rapid drainage of waste slurry, effectively avoiding polishing defects caused by insufficient polishing slurry or waste slurry accumulation in certain areas.

[0036] To further improve the efficiency of waste liquid discharge and prevent the waste liquid from splashing and contaminating the workbench surface due to centrifugal force, a number of collection tanks 7 are evenly spaced along the top edge of the polyurethane polishing layer 3 on the outer side of the inner groove 4. The location of the collection tanks 7 allows them to effectively collect the waste liquid flowing out from the inner groove 4 and the drainage channel 6. To ensure smooth flow of waste liquid from the inner groove 4 to the collection tanks 7, guide holes 8 are provided on the side walls of the collection tanks 7. The other ends of these guide holes 8 extend to the bottom of the inner groove 4, thus establishing a direct waste liquid channel between the inner groove 4 and the collection tanks 7. By utilizing the blocking effect of the side walls of the collection tanks 7 on the polishing waste liquid, the flow rate of the polishing waste liquid is reduced, preventing the polishing waste liquid from splashing and dispersing from the edge of the polyurethane polishing layer 3, thereby preventing the waste liquid from splashing and contaminating the polishing table surface and increasing the cleaning workload for workers.

[0037] The collection tank 7 is not merely a container for waste liquid; it also provides further filtration and discharge functions. The bottom plate of the collection tank 7 is uniformly perforated with filter holes arranged in an array. The diameter of the filter holes ranges from 0.1 mm to 0.5 mm, and the center-to-center distance between adjacent filter holes is 2 to 5 times the diameter of the filter hole. These filter holes extend through to the bottom of the base pad layer 1. The presence of the filter holes ensures that the waste liquid can ultimately be discharged from the gap between the bottom of the polishing pad and the polishing disc. To prevent large particles of abrasive or contaminants from clogging the filter holes and to perform preliminary filtration before waste liquid discharge, a filter cloth is laid on the bottom plate of the collection tank 7 above the filter holes. The selection of the filter cloth should consider its filtration accuracy, abrasion resistance, and chemical corrosion resistance to ensure long-term stable operation in the polishing fluid environment.

[0038] This embodiment achieves a high-performance CMP polishing pad with high efficiency, uniformity, and excellent waste liquid treatment capabilities through a combination of interlayer synergy, fine surface structure, and waste liquid guidance. The multi-layered composite structure of the base pad layer 1, elastic buffer pad layer 2, and polyurethane polishing surface layer 3, combined with surface-mounted grooves 4, a fine grinding head 5, a drainage channel 6, a liquid accumulation channel 7, and inverted V-shaped guide holes 8, forms a highly efficient polishing liquid distribution and waste liquid guidance system. This effectively blocks and guides the polishing liquid to flow orderly under centrifugal force, significantly reducing the splashing of polishing liquid from the edge of the polishing pad, thereby reducing contamination of the CMP polishing machine's worktable and lessening the cleaning workload.

[0039] Example 2:

[0040] Based on Example 1, this example further optimizes the waste liquid diversion system, focusing on improving the working efficiency and reliability of the guide hole 8.

[0041] Specifically, the guide hole 8 has an inverted V-shaped structure. This special V-shaped design has its tip pointing towards the liquid accumulation tank 7. The two openings slope downwards, and the length of the inclined channel on the side of the guide hole 8 closest to the inner groove 4 is greater than the length on the other side. Furthermore, the slope of the inclined channel on the side of the guide hole 8 closest to the inner groove 4 is greater than the slope of the other side. This allows the polishing waste liquid, centrifugally thrown from the center of the inner groove 4 and carrying polishing debris, to enter the guide hole 8. When it enters the inclined channel on the side of the guide hole 8 closest to the liquid accumulation tank 7, due to the different slopes of the two inclined channels, the polishing waste liquid impacts the upper sidewall of the inclined channel on the side of the guide hole 8 closest to the liquid accumulation tank 7, thus achieving a flow rate adjustment for the polishing waste liquid. This facilitates the separation of the polishing waste liquid and polishing debris, preventing the polishing waste liquid entering the liquid accumulation tank 7 from having excessive kinetic energy and flying out. More specifically, the two ends of the guide hole 8 are inclined downwards towards the inner groove 4 and the bottom plate of the liquid accumulation tank 7, respectively. This inclined V-shaped structure, combined with the downward-sloping port, utilizes gravity and the surface tension of the liquid to allow the waste liquid to flow more smoothly and quickly from the inner groove 4 to the collection tank 7. Especially during the polishing process, under the action of centrifugal force, the waste liquid is more likely to flow downwards along the guide path into the collection tank 7, effectively avoiding the phenomenon of waste liquid stagnation or backflow in the guide hole 8.

[0042] Furthermore, to maximize waste liquid collection efficiency and ensure complete drainage, the bottoms of the two ends of the guide hole 8 are flush with the bottom edges of the inner groove 4 and the liquid accumulation tank 7, respectively. This means that the lowest point of the guide hole 8 is precisely aligned with the bottom of the inner groove 4 and the liquid accumulation tank 7, thereby maximizing the collection of waste liquid in these two areas to reduce dead zones and residues. In addition, to better collect grinding waste liquid in the inner groove 4 area, the port of the guide hole 8 near the inner groove 4 is flared. The flared port has a larger inlet area, enabling it to more effectively "capture" waste liquid flowing towards the bottom of the inner groove 4, further improving waste liquid collection and drainage efficiency. This optimized guide hole 8 structure ensures rapid and complete drainage of waste liquid during polishing, thereby keeping the polished surface clean and reducing secondary contamination and polishing defects.

[0043] Furthermore, this embodiment enhances the functionality of the base pad layer 1 and the elastic buffer pad layer 2. A number of mounting slots 11 are evenly spaced along the bottom edge of the base pad layer 1. The mounting slots 11 have a trapezoidal or dovetail-shaped cross-section and are used to securely mount the polishing pad onto the polishing turntable of the CMP equipment, ensuring stability and positioning accuracy during the polishing process. Simultaneously, elastic support columns 12 are fixedly connected to the top of the base pad layer 1, corresponding to the polishing head 5. These elastic support columns 12 extend vertically upwards and provide localized elastic support for the polishing head 5 in the polyurethane polishing surface layer 3. They are typically made of polyurethane material with appropriate hardness and elasticity, capable of undergoing a certain degree of deformation under polishing pressure, thereby further adjusting the uniformity of the polishing pressure and extending the service life of the polishing head 5.

[0044] To ensure effective integration between the elastic support column 12 and the upper structure, expansion joints 21 are provided on the elastic buffer pad 2 corresponding to the elastic support column 12. The diameter of these expansion joints 21 is designed to be slightly larger than the outer diameter of the elastic support column 12, so that when the elastic buffer pad 2 is pressed and fixedly connected to the top of the base pad 1, the expansion joints 21 can correspondingly encircle the outside of the elastic support column 12. This design ensures that when the elastic buffer pad 2 is bonded to the base pad 1, stress concentration or uneven deformation will not occur due to the obstruction of the elastic support column 12, while allowing the elastic support column 12 to freely expand and contract during polishing, providing dynamic support.

[0045] Furthermore, the bottom of the polyurethane polished surface layer 3 is provided with embedded slots 51 corresponding to the elastic support pillars 12. These embedded slots 51 are plug-in structures designed for the top of the elastic support pillars 12. The top of the embedded slots 51 extends into the interior of the grinding head 5. This means that the depth of the embedded slots 51 is sufficient to accommodate the top of the elastic support pillars 12 and directly connect to the bottom of the grinding head 5. When the polyurethane polished surface layer 3 is pressed and fixed on the top of the elastic buffer pad layer 2, the top of the elastic support pillars 12 can be precisely engaged in the embedded slots 51. This engaging connection method not only allows the grinding head 5 to directly obtain elastic support from the elastic support pillars 12, enhancing the local buffering performance and wear resistance, but also greatly enhances the mechanical connection strength between the layers, prevents delamination, and improves the overall stability and service life of the polishing pad.

[0046] Furthermore, to further optimize waste liquid collection and discharge, the collection tank 7 has a U-shaped structure. The U-shaped structure helps to increase the collection capacity and makes it easier to process and clean. The end opening of the collection tank 7 extends to the side wall of the polyurethane polishing layer 3, providing a convenient channel for the final discharge of waste liquid within the collection tank 7. Importantly, the bottom plate of the collection tank 7 is set at a higher height than the bottom plate of the inner groove 4. This height difference design, combined with the inclined setting of the guide hole 8, utilizes gravity to ensure that the waste liquid in the inner groove 4 can flow efficiently to the collection tank 7, preventing the waste liquid from remaining in the inner groove 4 for a long time. Simultaneously, the relative height difference between the collection tank 7 and the inner groove 4 converts the kinetic energy of the polishing waste liquid centrifugally ejected from the inner groove 4 into relative gravitational potential energy, thereby further reducing the flow velocity of the polishing waste liquid entering the collection tank 7 and further preventing the polishing waste liquid from entering the collection tank 7 at excessive speed and colliding with and being ejected from the collection tank 7, causing splashing.

[0047] For ease of installation, replacement, and sealing of the polishing pad, an annular notch 31 is provided on the sidewall of the polyurethane polishing surface layer 3 on the outer side of the liquid collection tank 7 port. The annular notch 31 provides space for installing external seals. Positioning holes 32 are provided on the sidewall of the annular notch 31 between adjacent liquid collection tanks 7. These positioning holes 32 are used for precise alignment during installation. An elastic sealing ring 9 is provided on the outer wall of the annular notch 31. The elastic sealing ring 9 uses its own elastic tension to clamp at the annular notch 31. Positioning pins 91 are fixedly connected to the inner wall of the elastic sealing ring 9 at the corresponding positioning holes 32. The elastic sealing ring 9 is made of fluororubber or silicone material, and its cross-section is circular or rectangular; the positioning pins 91 and the positioning holes 32 are interference fit. The cooperation of this elastic sealing ring 9 with the annular notch 31, positioning hole 32 and positioning pin 91 enables the polishing pad to achieve a reliable seal when installed on the equipment, preventing the polishing fluid from leaking from the side wall of the sump 7. At the same time, it facilitates the quick installation and removal of the polishing pad, so as to clean the polishing debris accumulated in the sump 7. It can be cleaned and discharged at the side port of the sump 7 simply by scraping.

[0048] This embodiment further optimizes the material parameters of the polishing pad. The Shore D hardness of the elastic support column 12 is preferably 50-70. Materials within the Shore D hardness range can provide sufficient support strength while maintaining the necessary elasticity to effectively buffer polishing pressure. If the hardness is too low, the support effect is poor; if the hardness is too high, the buffering effect is weakened. The inner diameter of the telescopic vent 21 is preferably 0.1-0.3 mm larger than the outer diameter of the elastic support column 12. This gap ensures that the telescopic vent 21 can smoothly fit around the outside of the elastic support column 12 and allows the elastic support column 12 sufficient free deformation space under pressure without affecting its elastic function due to friction or excessive constraint. The depth of the embedded groove 51 is preferably 1 / 3 to 1 / 2 of the height of the grinding head 5. This depth range allows the top of the elastic support column 12 to be firmly embedded inside the grinding head 5, providing stable support, while avoiding the embedded groove 51 being too deep and weakening the strength of the grinding head 5 itself, or too shallow and resulting in an unstable connection.

[0049] Example 3:

[0050] Furthermore, such as Figure 6 As shown, this embodiment provides a polyurethane-based material

[0051] The preparation method of high-performance CMP polishing pads is as follows: Step 1: Pre-fabrication and functionalization of precision layered blanks:

[0052] First, initial blanks with a three-layer structure are prepared. Using high-hardness, high-elasticity polyurethane material, the base layer 1 blank is precision injection molded as a single piece. This blank must simultaneously form the mounting groove 11 and the elastic support column 12. Subsequently, an elastic buffer layer 2 blank with a uniform microporous structure is prepared using controlled foaming technology. Expansion vents 21, corresponding to the positions of the elastic support columns 12 on the base layer 1, are precisely machined into this blank using CNC punching. Finally, using a specially designed multi-cavity mold, a polyurethane polished surface layer 3 blank is cast using polyurethane reaction injection molding technology. This blank forms the inner groove 4, precision grinding head 5, drainage groove 6, liquid accumulation groove 7, and the bottom embedded slot 51 in a single process within the mold. After the blank has solidified, an inverted V-shaped guide hole 8 with a flared end is engraved on the side wall of the liquid accumulation groove 7 using a UV laser precision machining system.

[0053] Step 2: Interface activation and application of special adhesive:

[0054] The bonding interfaces of the prefabricated three-layer blanks were subjected to plasma surface activation treatment to significantly improve surface energy and bonding activity. Subsequently, a specially formulated high-toughness, low-creep polyurethane adhesive was uniformly coated onto the top of the base pad 1 and the upper and lower interfaces of the elastic buffer pad 2 using a slot coating device. During the coating process, the coating pressure and speed were precisely controlled to ensure that the adhesive covered the area around the elastic support column 12 and the inner wall of the expansion vent 21, while preventing the adhesive from clogging the expansion vent 21.

[0055] Step 3: Alignment bonding and stepped compression curing of multi-layer structures:

[0056] The elastic cushioning layer 2, coated with adhesive, is precisely aligned onto the base layer 1, ensuring that each elastic support column 12 accurately passes through the corresponding expansion hole 21. Next, the polyurethane polished surface layer 3 is aligned and placed on the elastic cushioning layer 2, so that the top of the elastic support column 12 is embedded in the recessed slot 51. Subsequently, the assembled three-layer structure is fed into a multi-stage press to implement a stepped pressing and curing process: first, a lower pressure is applied to initially bond the layers and remove interface air bubbles, then the pressure is stepped up to the rated pressure and maintained, while the adhesive is fully cross-linked and cured under heating conditions, ultimately forming an integrated structure with a dual fixing mechanism of mechanical interlocking (support column-slot) and chemical bonding.

[0057] Step 4: Integration of functional components and final sealing assembly:

[0058] Functional components are integrated onto the integrated pad after pressing and curing. First, pre-cut microporous filter cloth is precisely laid above the filter holes at the bottom of the liquid collection tank 7, and its edges are fixed with an environmentally friendly adhesive. Then, a small amount of lubricating grease-type sealant (made with polyurethane, silicone, or fluorocarbon compound as base oil and thickener added) is applied to the annular notch 31 on the side wall of the polyurethane polished surface layer 3. The elastic sealing ring 9 is then elastically tensioned and fitted onto the notch. The positioning pin 91 on its inner wall engages with the positioning hole 32 on the polyurethane polished surface layer 3 to complete the final sealing assembly, effectively sealing the side port of the liquid collection tank 7 to prevent polishing liquid leakage and overflow.

[0059] Step 5: Final Curing and Performance Testing

[0060] The assembled polishing pads are placed in a constant temperature and humidity curing chamber for 24-48 hours of static curing to allow for the full release of internal stress in each component and to achieve optimal bonding performance. After curing, the finished product undergoes a comprehensive inspection of its appearance and dimensions, a sealing performance test, and a polishing fluid flow distribution test under simulated working conditions to ensure that the product fully meets the design specifications.

[0061] The preparation method of this embodiment makes full use of the plasticity and adhesion of polyurethane material. Through step-by-step prefabrication and fine assembly, it ensures the precise fit and stable connection between each layer and substructure of the polishing pad, thereby maximizing the excellent performance of the polishing pad described in Examples 1 and 2.

[0062] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A high-performance CMP polishing pad based on polyurethane material, characterized in that, Includes a base pad layer (1) and an elastic buffer pad layer (2) pressed and fixed on top of the base pad layer (1). A polyurethane polished surface layer (3) is pressed and fixedly connected to the top of the elastic buffer pad layer (2). An inner groove (4) is provided on the top of the polyurethane polished surface layer (3). Several fine grinding heads (5) are evenly and fixedly connected to the bottom plate of the inner groove (4). Adjacent fine grinding heads (5) are evenly arranged to form a crisscrossing and interconnected drainage channel (6). The top edge of the polyurethane polished surface layer (3) on the outside of the inner groove (4) is evenly and uniformly connected. A number of liquid collection tanks (7) are spaced apart. Each liquid collection tank (7) has a guide hole (8) on its side wall. The other end of each guide hole (8) extends to the bottom of the inner groove (4). Filter holes are evenly distributed on the bottom plate of the liquid collection tank (7). The filter holes extend through to the bottom of the base pad (1). Filter cloth is laid on the bottom plate of the liquid collection tank (7) above the filter holes. The guide hole (8) has an inverted V-shaped structure. The two ends of the guide hole (8) are inclined downwards towards the inner groove (4) and the bottom plate of the liquid collection tank (7).

2. The high-performance CMP polishing pad based on polyurethane material according to claim 1, characterized in that: The bottom of the two ends of the guide hole (8) is flush with the bottom edge of the inner groove (4) and the liquid accumulation tank (7), respectively. The port of the guide hole (8) near the inner groove (4) is set in a trumpet shape.

3. The high-performance CMP polishing pad based on polyurethane material according to claim 1, characterized in that: The base pad (1) has several mounting slots (11) evenly spaced at the bottom edge, and elastic support columns (12) are fixedly connected to the top of the base pad (1) at the location corresponding to the grinding head (5).

4. The high-performance CMP polishing pad based on polyurethane material according to claim 3, characterized in that: The elastic buffer pad (2) is provided with telescopic air holes (21) respectively at the elastic support column (12). When the elastic buffer pad (2) is pressed and fixed to the top of the base pad (1), the telescopic air holes (21) are respectively encircled outside the elastic support column (12).

5. The high-performance CMP polishing pad based on polyurethane material according to claim 4, characterized in that: The polyurethane polished surface layer (3) has an embedded slot (51) at the bottom corresponding to the elastic support column (12). The top of the embedded slot (51) extends into the interior of the fine grinding head (5). When the polyurethane polished surface layer (3) is pressed and fixed to the top of the elastic buffer pad layer (2), the top of the elastic support column (12) is embedded in the embedded slot (51).

6. The high-performance CMP polishing pad based on polyurethane material according to claim 5, characterized in that: The liquid accumulation tank (7) has a U-shaped structure. The end opening of the liquid accumulation tank (7) extends to the side wall of the polyurethane polished surface layer (3), and the bottom plate of the liquid accumulation tank (7) is set at a height higher than the bottom plate of the inner groove (4).

7. The high-performance CMP polishing pad based on polyurethane material according to claim 6, characterized in that: An annular notch (31) is provided on the side wall of the polyurethane polished surface layer (3) on the outer side of the liquid accumulation tank (7). A positioning hole (32) is provided on the side wall of the annular notch (31) between adjacent liquid accumulation tanks (7). An elastic sealing ring (9) is provided on the outer wall of the annular notch (31). A positioning pin (91) is fixedly connected on the inner wall of the elastic sealing ring (9) at the corresponding positioning hole (32). The positioning pin (91) matches the positioning hole (32).

8. The high-performance CMP polishing pad based on polyurethane material according to claim 1, characterized in that: The Shore D hardness of the elastic support column (12) is 50-70, the inner diameter of the telescopic air hole (21) is 0.1-0.3 mm larger than the outer diameter of the elastic support column (12), and the depth of the embedded groove (51) is 1 / 3 to 1 / 2 of the height of the fine grinding head (5).

9. The method for preparing a high-performance CMP polishing pad based on polyurethane material according to claim 7, characterized in that, The implementation steps include the following: S1. Prefabrication and processing: Prefabricated bodies of base pad (1), elastic buffer pad (2) and polyurethane polished surface (3) are prepared respectively; wherein, the base pad (1) prefabricated body is integrally formed with mounting groove (11) and elastic support column (12), the elastic buffer pad (2) prefabricated body is provided with telescopic air hole (21) matching the elastic support column (12), the polyurethane polished surface (3) prefabricated body is formed with inner groove (4), fine grinding head (5), drainage groove (6), liquid accumulation groove (7) and bottom embedded slot (51), and a guide hole (8) connecting the inner groove (4) and the liquid accumulation groove (7) is processed. S2, Adhesive application and assembly: Apply adhesive to the interface of each preform, and then assemble it so that the elastic support column (12) passes through the telescopic vent (21) and the top of the elastic support column (12) is inserted into the embedded slot (51) to form an uncured three-layer stacked structure. S3, Adhesive Pressing and Curing: Apply pressure to the three-layer laminated structure to press and fix each layer into an integrated composite pad through the adhesive; S4. Functional component installation: Filter holes are machined on the bottom plate of the liquid accumulation tank (7) and filter cloth is installed. An elastic sealing ring (9) is installed at the annular notch (31) on the side wall of the polyurethane polishing surface layer (3) to complete the preparation of the polishing pad.

Images