Polishing pad for wafer polishing

Abstract

The invention discloses a polishing pad for wafer polishing, and relates to the technical field of semiconductor preparation. The polishing pad comprises a composite substrate layer and a polishing layer, the polishing layer is located on the top face of the composite substrate layer and comprises a flat layer and diamond micro-powder partially embedded in the flat layer, the mass ratio of a rigid material to a flexible material to carbon fibers in the composite substrate layer is any one of (4-6): (2-4): (1-2), the compression ratio of the flat layer is any one of 1.5%-2.0%, and the compression ratio of the flexible material to the carbon fibers is any one of 1.5%-2.0%. When the polishing pad is matched with a lubricant for use, a wafer can be polished until the surface roughness Ra is any value of 0.4 nm-0. 6nm. According to the polishing pad, microscopic uniform cutting can be achieved on the basis of stable pressure transmission in the polishing process, so that the wafer polishing effect with the surface roughness Ra ranging from 0.4 nm to 0.6 nm is stably obtained under the condition that the polishing pad is used in cooperation with a lubricant, and the polishing pad has better polishing performance and longer polishing service life.

Description

Technical Field

[0001] This invention relates to the field of semiconductor fabrication technology, specifically to a polishing pad for wafer polishing. Background Technology

[0002] Chemical mechanical polishing (CMP) is a key process in semiconductor manufacturing, optical device processing, and high-end material surface treatment. Its core objective is to continuously reduce wafer surface roughness and stably control polishing uniformity while ensuring material removal efficiency. The polishing pad, as a crucial consumable directly involved in mechanical action and pressure transmission in the CMP process, has a decisive impact on wafer surface quality, material removal rate stability, and polishing lifespan due to its structural design and material properties.

[0003] Existing polishing pads typically employ a single polyurethane matrix or a simple composite structure, with their polishing performance primarily dependent on trench structure design, foam density adjustment, or optimization of the polishing slurry system. However, under high-pressure, high-precision nanoscale polishing conditions, these pads generally suffer from a difficulty in balancing overall rigidity and flexibility. This means they are prone to excessive compression deformation during polishing, leading to uneven load distribution and consequently, over-polishing of wafer edges, under-polishing of localized areas, or significant fluctuations in surface roughness. Furthermore, polishing pads are susceptible to permanent compressive deformation and fatigue damage after prolonged use, resulting in a significant decrease in material removal rate and a short service life.

[0004] In addition, to improve polishing efficiency and reduce surface roughness, existing technologies have attempted to introduce hard micro-abrasives into the surface of the polishing pad or the substrate, such as through filler mixing, sandblasting, or surface coating to form a grinding structure. However, these methods often result in uneven abrasive distribution, local agglomeration, or abrasive detachment, making it difficult to form a stable and controllable micro-cutting interface. This also easily causes scratches on the wafer surface and even cracking due to polishing pad embrittlement. Furthermore, the random exposure height of the abrasives is difficult to control, making it difficult to maintain consistent material removal rate and surface roughness over the long term. Summary of the Invention

[0005] One objective of this invention is to provide a polishing pad for wafer polishing, thereby solving the technical problem that existing polishing pads for wafer polishing require the use of polishing fluid, which can easily lead to accelerated wear and shortened service life.

[0006] Another objective of this invention is to further improve the service life of polishing pads.

[0007] According to the purpose of this invention, a polishing pad for wafer polishing is provided, comprising: Composite substrate layer; A polishing layer, located on the top surface of the composite substrate, comprises a flat layer and diamond micropowder partially embedded within the flat layer; wherein... The mass ratio of rigid material, flexible material and carbon fiber in the composite substrate layer is any one of (4-6):(2-4):(1-2), and the compression rate of the flat layer is any one of 1.5%-2.0%, so that when the polishing pad is used in conjunction with the lubricant, the wafer can be polished to a surface roughness Rq of any one of 0.4nm-0.6nm.

[0008] Optionally, the diamond micro powder is prepared by atomization sputtering.

[0009] Optionally, the particle size of the diamond powder is any value between 0.5 μm and 3.0 μm.

[0010] Optionally, the tensile strength of the carbon fiber is any value between 2500MPa and 4000MPa, and the elongation is any value between 0.8% and 1.2%.

[0011] Optionally, the thickness of the flat layer is any value between 1.1 mm and 1.5 mm.

[0012] Optionally, the preset cavity pressure of the atomization sputtering process is any value between 5MPa and 10MPa.

[0013] Optionally, the rigid material is any one of epoxy resin, glass fiber, thermosetting polyurethane, or thermoplastic polyurethane.

[0014] Optionally, the pressure for the planarization treatment of the polishing pad is any value between 2 MPa and 5 MPa.

[0015] Optionally, the flexible material is any one of nylon, polyester, polyurethane, or nonwoven fabric.

[0016] This invention constructs a multi-parameter synergistic system within the polishing pad, comprising a multi-component mass ratio of a composite substrate layer, an embedded diamond micropowder structure in the polishing layer, and a controlled compressibility of the planar layer. This system achieves a balance and complementarity in the polishing pad's mechanical support, compliance, localized micro-cutting capability, and macroscopic deformation control. During polishing, it enables microscopic uniform cutting while maintaining stable pressure transmission. Thus, when used with a lubricant, it consistently achieves a wafer polishing effect with a surface roughness Ra of 0.4nm-0.6nm, reaching an atomically smooth surface. Compared to existing technologies that improve material removal and fluid distribution by adjusting the polishing pad's groove structure or altering the polishing slurry's properties, the polishing pad of this application exhibits superior polishing performance, longer polishing life, and a higher yield.

[0017] Furthermore, the diamond micro powder prepared by the atomization sputtering process of this invention has the characteristics of narrow particle size distribution, uniform morphology and high purity, which enables it to maintain a stable and consistent protrusion height after being embedded in the polishing layer, thereby forming a uniform micro-cutting field. This avoids the problems of local over-polishing, micro-scratching or abrasive grain shedding caused by the discrete size or sharp edges of diamond particles in the traditional crushing method, and improves the service life of the polishing pad.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic structural diagram of diamond micropowder in a polishing pad according to an embodiment of the present invention; Figure 2 This is a schematic particle size distribution diagram of a polishing pad according to an embodiment of the present invention; Figure 3 This is a physical image of the polishing pad according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the surface roughness distribution of the polishing pad according to Embodiment 1 of the present invention; Figure 5 This is a physical image of the polishing pad according to Comparative Example 1 of the present invention; Figure 6 This is a schematic diagram of the surface roughness distribution of the polishing pad according to Comparative Example 1 of the present invention; Figure 7 This is a photograph of the polishing pad according to Embodiment 1 of the present invention under strong light. Figure 8 This is a photograph of the polishing pad according to Comparative Example 1 of the present invention under strong light.

[0020] Figure label: 100 - Polishing pad, 10 - Composite substrate layer, 20 - Flat layer, 30 - Diamond micro powder. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0023] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] Figure 1 This is a schematic structural diagram of diamond micropowder in a polishing pad according to an embodiment of the present invention. Figure 2 This is a schematic particle size distribution diagram of a polishing pad according to an embodiment of the present invention. Figure 3 This is a photograph of the polishing pad according to Embodiment 1 of the present invention. Figure 4 This is a schematic diagram showing the surface roughness distribution of the polishing pad according to Embodiment 1 of the present invention. Figure 5 This is a physical image of the polishing pad according to Comparative Example 1 of the present invention. Figure 6 This is a schematic diagram of the surface roughness distribution of the polishing pad according to Comparative Example 1 of the present invention. Figure 7 This is a photograph of the polishing pad according to Embodiment 1 of the present invention under strong light. Figure 8 This is a photograph of the polishing pad according to Comparative Example 1 of the present invention under strong light.

[0026] like Figure 1As shown, the present invention provides a polishing pad 100 for wafer polishing to polish the wafer surface to a target roughness. The polishing pad 100 includes a composite substrate layer 10 and a polishing layer 20 located on the top surface of the composite substrate layer 10. The polishing layer 20 includes a flat layer 21 and diamond micropowder 22 partially embedded in the flat layer 21. The mass ratio of rigid material, flexible material and carbon fiber in the composite substrate layer 10 is any value of (4-6):(2-4):(1-2), and the compression ratio of the flat layer 21 is any value of 1.5%-2.0%, so that when the polishing pad 100 is used in conjunction with a lubricant, it can polish the wafer to a surface roughness Ra of any value of 0.4nm-0.6nm. Here, the polishing pad 100 is used in conjunction with a lubricant to polish the wafer, so that the surface roughness Ra of the wafer can reach 0.4nm, 0.45nm, 0.5nm, 0.55nm or 0.6nm, or any other value between 0.4nm and 0.6nm. The compression rate of the planar layer 21 can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2.0%, or any other value between 1.5% and 2.0%. The material of the planar layer is aramid fiber.

[0027] It should be noted that, in order to simultaneously address the problems of difficulty in reducing surface roughness during wafer polishing, insufficient uniformity due to large compression deformation of the polishing pad 100, and generally short lifespan of the polishing pad 100, the inventors have tried various existing technical approaches, including optimizing the trench type, changing the polyurethane foam density, introducing composite layer structures with different hardness levels, and even adjusting the wettability of the polishing slurry on the pad surface to improve fluid distribution. However, no matter how these single-directional control methods are combined, the resulting polishing pad 100 still exhibits technical problems under high-pressure chemical mechanical polishing processes, such as unstable material removal rate, local flow surface disturbance leading to over-polishing of wafer edges or local areas, and a sharp decline in performance of the polishing pad 100 after 150-165 hours of use. It has always been impossible to simultaneously achieve core indicators such as surface roughness, total thickness change, material removal rate, and lifespan.

[0028] Furthermore, in attempting to improve the rigidity and uniformity of the abrasive particles, the inventors also tried introducing micro-abrasive particles into the pad surface by increasing fillers, improving the hardness of polyurethane, or using mechanical sandblasting. However, these methods either resulted in embrittlement of the pad surface, excessively low compressibility, making the pad surface more prone to cracking on high-pressure machines, or caused uneven distribution of abrasive particles, leading to localized scratches on the wafer or an increase in surface roughness. In addition, if diamond micropowder 22 is directly mixed into the polymer matrix, the micropowder often settles, agglomerates, or randomly distributes during the curing process, failing to form a stable, controllable abrasive structure with a consistent grinding depth on the pad surface. This can even lead to blockage of the micropores on the pad surface, making it difficult for the polishing slurry to maintain fluidity and further deteriorating the polishing uniformity.

[0029] In fact, even if diamond micropowder 22 is successfully consolidated locally on the pad surface, the non-uniformity of the mechanical properties of the composite substrate layer 10 and the difficulty in stably controlling the compressibility of the flat layer 21 will lead to inconsistent exposure heights of the diamond micropowder 22 under actual chemical mechanical polishing conditions. This makes it impossible to maintain stable nanoscale micro-cutting behavior, resulting in significant fluctuations in surface roughness and making it difficult to reconcile surface roughness, total thickness variation, material removal rate, and lifetime performance parameters. Therefore, it is impossible to obtain the overall performance required by this application by focusing solely on any one of the technical directions of the polishing pad 100, such as the pad material formulation, abrasive method, or fluid characteristics.

[0030] In this embodiment, by constructing a multi-parameter synergistic system in the polishing pad 100, consisting of a multi-component mass ratio of the composite substrate layer 10, an embedded diamond micropowder 22 structure in the polishing layer 20, and a controlled compressibility of the planar layer 21, the polishing pad 100 achieves a balance and complementarity in terms of mechanical support, compliance, local micro-cutting capability, and macroscopic deformation control. This allows for microscopic uniform cutting during polishing while maintaining stable pressure transmission. Thus, when used with a lubricant, a stable wafer polishing effect with a surface roughness Rq of 0.4nm-0.6nm is achieved, resulting in an atomically smooth surface. Compared with existing technologies that improve material removal and fluid distribution by adjusting the groove structure of the polishing pad 100 or changing the characteristics of the polishing fluid, the polishing pad 100 of this application exhibits superior polishing performance, longer polishing life, and higher yield.

[0031] In this embodiment, the mass ratio of rigid material, flexible material, and carbon fiber in the composite substrate layer 10 can be 4:4:2, 4.5:3.5:2, 5:3:2, 5.5:3.5:1, 5.5:3:1.5, or 6:3:1, or any value in (4-6):(2:4):(1-2). The addition of rigid material to the composite substrate ensures that the polishing pad 100 maintains the stability of its overall geometry under polishing pressure, allowing the load to be evenly distributed to the polishing layer 20 and avoiding localized soft collapse. Over-polishing or concavation can be avoided, and flexible materials can absorb transient load changes, forming a smooth and gradual pressure transmission path. This prevents the wafer surface from being subjected to strong impacts during the polishing process, improving polishing uniformity. Furthermore, the addition of carbon fiber not only enhances the bending resistance and fatigue life of the composite substrate layer 10, but also, due to its excellent modulus and deformation response characteristics, makes the polishing pad 100 lightweight, strong, and resistant to deformation. This allows for the optimal balance between high-stability support and smooth adhesion to the wafer micro-morphology, achieving nanoscale polished surface roughness.

[0032] In this embodiment, the flat layer 21 provides a relatively uniform and continuous medium, allowing the polishing pressure to be uniformly transmitted to the diamond micro powder 22 area, ensuring uniform distribution of micro-cutting action. At the same time, it also serves to encapsulate and fix the diamond micro powder 22, preventing diamond particles from falling off and causing scratches. Furthermore, by setting the compression ratio of the flat layer 21 to any value between 1.5% and 2.0%, the deformation of the polishing layer 20 under working load is controlled, ensuring that the effective protrusion height of the diamond micro powder 22 particles is stable and the cutting ability is consistent. This avoids uneven polishing caused by excessive compression, thereby achieving a controllable and stable micro-cutting interface, allowing the wafer surface material to be removed layer by layer to the sub-nanometer level.

[0033] In this embodiment, the rigid material, flexible material, and carbon fiber in the composite substrate layer 10 are combined in a specific mass ratio, enabling the polishing pad 100 to simultaneously possess structural stability, flexibility, and tear resistance, thus avoiding permanent compression deformation or fatigue damage under prolonged pressure and shearing, as is common with traditional single polyurethane substrates. Furthermore, the diamond micropowder 22 embedded in the polishing layer 20 maintains a stable exposed height within the compression ratio of the planar layer 21 (1.5%-2.0%), forming a self-healing micro-cutting effect. This means that as wear progresses, the embedded particles gradually and uniformly become exposed rather than detaching over a large area, significantly mitigating surface texture degradation and increased friction coefficient. Simultaneously, this compression ratio range avoids excessive hardness leading to surface brittleness, and also avoids excessive softness causing particle movement and accelerated wear. Therefore, the polishing pad 100 is far superior to traditional structures in terms of stress control, wear uniformity, and deformation stability, fundamentally reducing performance degradation during use and thus achieving a significant increase in service life.

[0034] In a further embodiment, the diamond micropowder 22 is prepared by atomization sputtering. Diamond micropowder 22 prepared by atomization sputtering has the characteristics of narrow particle size distribution, uniform morphology, and high purity. This allows it to maintain a stable and consistent protrusion height after being embedded in the polishing layer 20, thereby forming a uniform micro-cutting field. This avoids the problems of localized over-polishing, micro-scratching, or abrasive grain detachment caused by the size dispersion or sharp edges of diamond particles in traditional crushing methods. Furthermore, during polishing, the diamond micropowder 22 embedded by atomization sputtering experiences more uniform force, making it less prone to deep embedding or detachment. This significantly improves the grinding stability and wear resistance of the polishing pad 100, ensuring a stable material removal rate over a longer service life. Ultimately, this achieves the technical effects of lower surface roughness, higher batch-to-batch consistency, and a significantly extended overall service life for the polishing pad 100.

[0035] like Figure 2As shown, in a further embodiment, the particle size of the diamond micro powder 22 is any value between 0.5μm and 3.0μm, that is, the particle size of the diamond micro powder 22 can be 0.5μm, 1.0μm, 1.5μm, 2.0μm, 2.5μm, or 3.0μm, or any other value between 0.5μm and 3.0μm. In this embodiment, by limiting the particle size of the diamond micro powder 22 to any value between 0.5μm and 3.0μm, the polishing pad 100 achieves an optimal balance between micro-cutting capability, surface roughness, and wear stability, thereby maintaining efficient polishing capability and preventing deep pitting or particle shedding due to excessively large particle size, and preventing failure in the flat layer 21 due to excessively small particle size, thus avoiding defects such as uneven surface wear and early performance degradation in the polishing pad 100. Here, the particle size of the diamond micro powder 22 in the polishing pad is basically distributed at around 2.85μm.

[0036] In a further embodiment, the tensile strength of the carbon fiber is any value between 2500MPa and 4000MPa, and the elongation is any value between 0.8% and 1.2%. That is, the tensile strength of the carbon fiber can be 2500MPa, 3000MPa, 3500MPa, or 4000MPa, or any other value between 2500MPa and 4000MPa, and the elongation can be 0.8%, 0.9%, 1.0%, 1.1%, or 1.2%, or any other value between 0.8% and 1.2%. In this embodiment, setting the tensile strength of the carbon fiber to 2500MPa-4000MPa and the elongation to any value between 0.8% and 1.2% ensures that the composite substrate layer 10 possesses both high strength support capability and maintains necessary flexibility and fatigue resistance, thereby significantly improving the structural stability and service life of the polishing pad 100 under long-term high-pressure, high-speed reciprocating loads. Furthermore, the properties of the carbon fibers within the aforementioned range enable the composite substrate layer 10 and the flat layer 21 to synergize in terms of compression ratio, allowing the polishing pad 100 to maintain stable resilience under high-intensity conditions and avoid accelerated decay. This directly promotes the stability of total thickness variation, the uniformity of material removal rate, and a significant improvement in the lifespan of the polishing pad 100 during wafer polishing.

[0037] In a further embodiment, the thickness of the planar layer 21 is any value between 1.1mm and 1.5mm, that is, the thickness of the planar layer 21 can be 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm, or any other value between 1.1mm and 1.5mm. In this embodiment, the thickness of the planar layer 21 works synergistically with its compression ratio, enabling the polishing pad 100 to maintain stable resilience and prevent excessive softening under cyclic loading, while being sufficient to support the high-strength framework of the composite substrate layer 10, making the abrasive-wafer contact force more controllable and uniform.

[0038] In other embodiments, if the planar layer 21 is too thin, i.e., its thickness is less than 1.1 mm, its buffering and support capabilities are insufficient. This can lead to excessive deformation of the surface layer containing the diamond micropowder 22 during high-pressure polishing, resulting in unstable grinding contact surfaces, increased fluctuations in material removal rate, and accelerated fatigue degradation of the pad material. If the planar layer 21 is too thick, i.e., its thickness is greater than 1.5 mm, it will produce an excessive elastic delay effect, causing uneven polishing pressure transmission, obstructed fluid distribution, and affecting the overall wafer thickness variation and surface roughness control.

[0039] In a further embodiment, the preset chamber pressure of the atomizing sputtering process is any value between 5 MPa and 10 MPa. That is, the initial chamber pressure of the atomizing sputtering process can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa, or any other value between 5 MPa and 10 MPa. In this embodiment, controlling the preset chamber pressure of the atomizing sputtering process within the range of 5 MPa to 10 MPa can establish a stable and controllable jetting kinetic energy and agglomeration environment during the formation and deposition of diamond micropowder 22. This significantly improves the particle size uniformity, nucleation density, embedding depth consistency, and surface density of the diamond micropowder 22, ensuring that when the diamond micropowder 22 is embedded into the planar layer 21, it will not form agglomerated particles due to excessively low pressure, nor will it cause excessive breakage of the micropowder and an increase in morphological defects due to excessively high pressure.

[0040] In a further embodiment, the rigid material is any one of epoxy resin, glass fiber, thermosetting polyurethane, or thermoplastic polyurethane. These materials all possess high modulus, high strength, and low creep characteristics, enabling them to serve as the mechanical framework of the polishing pad 100. Under the high-pressure, high-speed cyclic load of chemical mechanical polishing, they maintain shape and thickness stability, preventing permanent compression, warping, or fatigue cracking of the composite substrate layer 10. Simultaneously, the availability of different materials allows for flexible matching of the stiffness and elasticity of the composite substrate layer 10 according to operational requirements, synergizing with the compression ratio of the flat layer 21. This achieves stable and uniform pressure transmission during polishing, thereby improving the uniformity of material removal rate and reducing fluctuations in total thickness variation.

[0041] In a further embodiment, the planarization pressure of the polishing pad 100 is any value between 2MPa and 5MPa. That is, the planarization pressure of the polishing pad 100 can be 2MPa, 2.5MPa, 3MPa, 4MPa, or 5MPa, or any other value between 2MPa and 5MPa. In this embodiment, controlling the planarization pressure of the polishing pad 100 within the range of 2MPa to 5MPa can effectively regulate its surface microstructure and compression deformation state before the polishing pad 100 is put into use, thereby significantly improving the uniformity of pressure distribution and grinding consistency during the polishing process.

[0042] In a further embodiment, the flexible material is any one of nylon, polyester, polyurethane, or nonwoven fabric, providing the polishing pad 100 with appropriate elasticity and cushioning properties, thereby achieving uniform pressure distribution and shock absorption protection during high-pressure, high-speed polishing.

[0043] The technical solution of this application will be further described below with reference to specific embodiments.

[0044] Example 1 Polishing pad 100 (e.g.) Figure 3 The composite substrate 10 includes a composite substrate 10, a flat layer 21, and diamond micropowder 22 partially embedded in the flat layer 21. The mass ratio of epoxy resin, polyurethane, and carbon fiber in the composite substrate 10 is 4:4:2. The compression ratio of the flat layer 21 is 1.5%. When the polishing pad 100 is used with a lubricant, it can polish the wafer to a surface roughness Rq of 0.6 nm. The diamond micropowder 22 is prepared by atomization sputtering process. The particle size of the diamond micropowder 22 is 2.0 μm. The polishing time is 60 min. The tensile strength of the carbon fiber is 3000 MPa, and the elongation is 1.0%.

[0045] Example 2 The only difference between Example 2 and Example 1 is that the polishing time for the polishing pad 100 with lubricant for wafer polishing is 120 minutes.

[0046] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the polishing pad needs to be used in conjunction with the polishing slurry for polishing the wafer, and the polishing pad comprises 98% polyurethane, 1% nylon, and 1% nonwoven fabric (see reference). Figure 5 The polishing fluid flow rate is 50 mL / min.

[0047] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the polishing pad 100 is provided with grooves to accommodate the distribution of polishing liquid. The polishing pad 100 comprises 98% polyurethane and 2% nylon, and the flow rate of the polishing liquid is 50 mL / min.

[0048] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the polishing pad 100 needs to be used in conjunction with the polishing slurry to polish the wafer. The polishing pad 100 is made of 98% polyurethane, 1.5% nylon and 0.5% non-woven fabric, and the flow rate of the polishing slurry is 50 mL / min.

[0049] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the polishing pad 100 is made of polyurethane, and the polishing pad 100 needs to be used in conjunction with polishing fluid for polishing the wafer. The flow rate of the polishing fluid is 50 mL / min.

[0050] First, the surface roughness of the polishing pads 100 in Example 1 and Comparative Example 1 was tested, and the results were as follows: Figure 4 and Figure 6 The test results are shown.

[0051] like Figure 3 and Figure 4 As shown, the polishing pad 100 of Example 1 has a smooth surface, and its multi-pore structure is densely packed and evenly distributed. According to... Figure 5 and Figure 6 As shown, the surface of the polishing pad 100 in Comparative Example 1 has significant grooves, and the surface roughness of the polishing pad 100 is large and unevenly distributed.

[0052] Next, the polishing pads 100 from Example 1 and Comparative Example 1 were used to polish the wafers, and the prepared wafers were then irradiated with a strong light to obtain the desired results. Figure 7 and Figure 8 The test results are shown.

[0053] like Figure 7 and Figure 8 As shown, the polished wafer prepared by the polishing pad 100 in Example 1 only has normal grinding spiral marks on its surface, while the polished wafer obtained by the polishing pad 100 in the comparative example has deeper scratches beyond the grinding, indicating that the polishing pad 100 in Example 1 can prepare polished wafers with better polishing performance than the comparative example 1.

[0054] Subsequently, the arithmetic average roughness (Ra) and average surface roughness (SA) of the wafers polished by polishing pad 100 in Examples 1-2 and Comparative Examples 1-4 were tested, and the test results are shown in Table 1.

[0055] Table 1. Roughness test results of polishing pads used for wafer polishing in Examples 1-2 and Comparative Examples 1-4 As shown in Table 1, the arithmetic mean roughness Ra and surface average roughness RA of the wafers polished by the polishing pads 100 in Examples 1 and 2 are significantly lower than those polished by the polishing pads 100 in Comparative Examples 1-4. This indicates that the polishing pad 100 of this application can achieve better surface planarization capability under the same polishing conditions. Lower Ra and SA indicate that the micro-protrusions on the wafer surface are removed more fully and uniformly, resulting in a finer surface morphology, better overall smoothness, and improved uniformity and stability of the polishing process. This further proves that the polishing pads 100 in Examples 1 and 2 have higher surface processing quality and better polishing performance.

[0056] Finally, the material removal rate (MRR) for thickness and weight was calculated for the wafers polished by polishing pad 100 in Example 1 and Comparative Examples 1-3, respectively, and the test results are shown in Table 2. The thickness material removal rate is MMR. h The weight material removal rate is MMR w .

[0057] Table 2. Material removal rate of wafers polished by polishing pad 100 in Examples 1 and Comparative Examples 1-3 As shown in Table 2, the MRR of the polishing pad 100 in Example 1 h and MRR w The values ​​of the two are the lowest and close, indicating that the polishing pad 100 of Example 1 has a lower overall removal rate during the polishing process, and the density consistency of the removal process is better. The material removal behavior is more stable and controllable. This shows that the polishing pad 100 of Example 1 has higher processing uniformity and fineness than the polishing pads 100 of Comparative Examples 1-3, which significantly improves the predictability of the polishing process and the stability of surface quality.

[0058] In summary, the polishing pad 100 in Examples 1 and 2 can polish the wafer to be polished by using the diamond micro powder 22 embedded in the flat layer 21, and can improve the service life of the polishing pad 100 to 300 hours, achieve a polished surface roughness at the nanometer level, and avoid the use of polishing liquid to reduce damage or contamination to the polishing equipment during the polishing process.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polishing pad for wafer polishing, characterized by, The polishing pad comprises: a composite substrate layer; a polishing layer on the top surface of the composite substrate layer, the polishing layer comprising a flat layer and diamond micro-powder partially embedded in the flat layer; wherein, the mass ratio of the rigid material, the flexible material and the carbon fiber in the composite substrate layer is any value in the range of (4-6):(2-4):(1-2), and the compression rate of the flat layer is any value in the range of 1.5%-2.0%, so that the polishing pad can polish the wafer to a surface roughness Rq of any value in the range of 0.4nm-0.6nm when used with a lubricant.

2. The polishing pad of claim 1, wherein the preparation process of the diamond micro-powder is a misting sputtering process.

3. The polishing pad of claim 2, wherein the particle size of the diamond micro-powder is any value in the range of 0.5μm-3.0μm.

4. The polishing pad of claim 3, wherein the tensile strength of the carbon fiber is any value in the range of 2500MPa-4000MPa, and the elongation is any value in the range of 0.8%-1.2%.

5. The polishing pad of claim 4, wherein the thickness of the flat layer is any value in the range of 1.1mm-1.5mm.

6. The polishing pad of claim 5, wherein the preset cavity pressure of the misting sputtering process is any value in the range of 5MPa-10MPa.

7. The polishing pad of any one of claims 1-6, wherein the rigid material is any one of epoxy resin, glass fiber, thermosetting polyurethane or thermoplastic polyurethane.

8. The polishing pad of claim 7, wherein the pressure of the planarization process of the polishing pad is any value in the range of 2MPa-5MPa.

9. The polishing pad of claim 1, wherein the flexible material is any one of nylon, polyester, polyurethane or non-woven fabric.

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