A polishing pad and a method of making the same

Abstract

The application provides a grinding pad and a preparation method thereof, and the preparation method comprises the following steps: (1) performing first lamination of a top layer and a first adhesive layer to obtain a preliminary material; (2) performing second lamination of the preliminary material in step (1) and a buffer layer to obtain an intermediate material, wherein the hardness of the buffer layer is 28-32 SHA; and (3) performing third lamination of the intermediate material in step (2) and a second adhesive layer to obtain the grinding pad. The preparation method uses a low-hardness buffer layer and a layer-by-layer hot-pressing lamination mode, effectively adjusts the hardness and surface flatness of the grinding pad, solves the problems of wafer surface scratching and defect generation in the grinding process in the prior art, and thus improves the wafer surface flatness and the yield of finished products.

Description

Technical Field

[0001] This invention belongs to the field of polishing pad technology, and relates to a polishing pad and its preparation method. Background Technology

[0002] Currently, due to technological advancements in the semiconductor industry, wafer surface planarization methods are attracting increasing attention. Wafer surface treatment employs chemical mechanical polishing (CMP). During CMP, the wafer is vacuum-adhered by a holding ring and, under pressure, is brought into close contact with the surface of the polishing pad / refining pad, face down. The surface smoothness of the wafer after polishing is the result of the coupling effect of the pressure applied by the holding ring and the basic physical properties, surface trench morphology, and distribution of the polishing pad. Among these factors, the hardness of the polishing pad is one of the key factors determining the overall quality performance of the wafer. High-hardness polishing pads can cause a series of problems such as scratches and defects on the wafer surface, thus affecting the yield of the finished product.

[0003] A polishing pad mainly consists of four parts: an upper pad, a hot-melt adhesive layer, a buffer pad, and a pressure-sensitive adhesive layer. The upper pad is in direct contact with the wafer during the polishing process and primarily performs the polishing function. The hot-melt adhesive layer mainly serves to bond the upper pad and the buffer pad. The buffer pad cushions the downward pressure from the retaining ring. The pressure-sensitive adhesive layer secures the entire polishing pad to the machine tool. Currently, the industry generally improves the overall polishing effect of the polishing pad by refining the synthesis method of the upper pad.

[0004] CN114536212A discloses a microporous thermoplastic polyurethane polishing pad and its semi-continuous preparation method, comprising the following steps: (1) melt extruding, calendering, and winding high-hardness thermoplastic polyurethane and additives; (2) subjecting the roll material to high-pressure fluid impregnation, low-temperature airlocking, low-temperature storage, heating foaming, and winding to obtain a foamed roll material; (3) peeling and punching the foamed roll material to obtain an upper pad; (4) grinding, grooving, and bonding backing adhesive to the upper pad, or bonding a buffer layer and backing adhesive to obtain a microporous thermoplastic polyurethane polishing pad; wherein the hardness of the high-hardness thermoplastic polyurethane is 55-85HD; the hardness of the upper pad is 25-80HD, the thickness is 1.3-2.0mm, and the density is 0.1-1.0g / cm³. 3 The pore size is 1–200 μm. The polishing pads prepared by the method have excellent polishing effect and polishing rate. However, the above preparation method is complex, requiring control of multiple process parameters to select the optimal upper pad formulation. The overall process is time-consuming, costly, and inconvenient to operate.

[0005] In summary, the goal is to develop a low-cost, simple, and low-hardness polishing pad preparation method to avoid scratches and defects on the wafer surface caused by the polishing pad, thereby improving wafer surface flatness and increasing finished product yield. Summary of the Invention

[0006] The purpose of this invention is to provide a polishing pad and its preparation method. The polishing pad obtained has low hardness and improves the surface flatness of the polishing pad. This solves the problem of wafer surface scratches and defects caused by the high hardness of the polishing pad during the chemical polishing process, thereby improving the surface flatness of the wafer and increasing the yield of finished products.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing an abrasive pad, the method comprising the following steps:

[0009] (1) The top layer and the first adhesive layer are bonded together to obtain the initial material;

[0010] (2) The initial material described in step (1) is bonded to the buffer layer for a second time to obtain the intermediate material;

[0011] The hardness of the buffer layer is 28-32 SHA, for example, it can be 28.5 SHA, 29 SHA, 29.5 SHA, 30 SHA, 30.5 SHA, 31 SHA or 31.5 SHA, etc., but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] (3) The intermediate material described in step (2) is bonded to the second adhesive layer in a third bonding process to obtain a grinding pad.

[0013] In this invention, when the initial material is bonded to the buffer layer for the second time, the first adhesive layer and the buffer layer of the initial material are combined. When the intermediate material is bonded to the second adhesive layer for the third time, the buffer layer and the second adhesive layer of the intermediate material are combined.

[0014] The preparation method provided by this invention effectively adjusts the hardness and surface flatness of the polishing pad by using a low-hardness buffer layer and a layer-by-layer hot-press bonding method. The polishing pad prepared by this method solves the problems of wafer surface scratches and defects in the existing polishing process, improves wafer surface flatness, and increases the yield of finished products.

[0015] As a preferred technical solution of the present invention, the material of the top layer (upper pad) in step (1) is polyurethane.

[0016] It is worth noting that the top layer, the first adhesive layer, the buffer layer, and the second adhesive layer are all pre-treated before bonding to ensure that the roughness and other properties of the finished grinding pad meet the standards.

[0017] In this invention, before the first bonding, the top layer further includes: using an automated cutting machine to cut regular windows on the surface of the top layer.

[0018] Preferably, the thickness of the top layer in step (1) is 2-3 mm, for example, it can be 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm or 2.9 mm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the hardness of the top layer in step (1) is 60-70 SHA, for example, it can be 61 SHA, 62 SHA, 63 SHA, 64 SHA, 65 SHA, 66 SHA, 67 SHA, 68 SHA or 69 SHA, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, in step (1), the first adhesive layer is a heat-sensitive double-sided adhesive.

[0021] In this invention, the heat-sensitive double-sided adhesive is a rubber-based heat-sensitive double-sided adhesive. Furthermore, this invention does not specifically limit the materials used for the heat-sensitive double-sided adhesive; those skilled in the art can select the appropriate materials based on the specific circumstances.

[0022] Preferably, the thickness of the first adhesive layer in step (1) is 50-100μm, for example, it can be 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm or 95μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] As a preferred technical solution of the present invention, the temperature of the first bonding in step (1) is 85-145℃, for example, it can be 90℃, 95℃, 100℃, 105℃, 110℃, 105℃, 120℃, 125℃, 130℃ or 140℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the pressure of the first bonding in step (1) is 2-5 bar, for example, it can be 2.2 bar, 2.5 bar, 2.7 bar, 3 bar, 3.2 bar, 3.5 bar, 3.7 bar, 4 bar, 4.2 bar, 4.5 bar, 4.7 bar or 4.9 bar, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] As a preferred technical solution of the present invention, the material of the buffer layer (buffer pad) in step (2) is porous polyurethane.

[0026] Preferably, the pore size of the porous polyurethane is 50-100μm, for example, it can be 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm or 95μm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the thickness of the buffer layer in step (2) is 0.5-1.1 mm, for example, it can be 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm or 1.05 mm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] As a preferred technical solution of the present invention, the temperature of the second bonding in step (2) is 85-145℃, for example, it can be 90℃, 95℃, 100℃, 105℃, 110℃, 105℃, 120℃, 125℃, 130℃ or 140℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the pressure of the second bonding in step (2) is 2-5 bar, for example, it can be 2.2 bar, 2.5 bar, 2.7 bar, 3 bar, 3.2 bar, 3.5 bar, 3.7 bar, 4 bar, 4.2 bar, 4.5 bar, 4.7 bar or 4.9 bar, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] As a preferred technical solution of the present invention, the second adhesive layer in step (3) is pressure-sensitive double-sided adhesive.

[0031] In this invention, the pressure-sensitive double-sided adhesive is a rubber-based pressure-sensitive double-sided adhesive. Furthermore, this invention does not specifically limit the materials used for the pressure-sensitive double-sided adhesive; those skilled in the art can select materials according to the actual situation.

[0032] Preferably, the thickness of the second adhesive layer in step (3) is 80-120 μm, for example, it can be 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm or 115 μm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] As a preferred technical solution of the present invention, the temperature of the third bonding in step (3) is 85-145℃, for example, it can be 90℃, 95℃, 100℃, 105℃, 110℃, 105℃, 120℃, 125℃, 130℃ or 140℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the pressure of the third bonding in step (3) is 2-5 bar, for example, it can be 2.2 bar, 2.5 bar, 2.7 bar, 3 bar, 3.2 bar, 3.5 bar, 3.7 bar, 4 bar, 4.2 bar, 4.5 bar, 4.7 bar or 4.9 bar, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] In this invention, in order to speed up production efficiency, the temperature and pressure of the first bonding in step (1), the second bonding in step (2), and the third bonding in step (3) can be the same value.

[0036] As a preferred technical solution of the present invention, after obtaining the grinding pad in step (3), the process also includes cutting and shaping and processing grooves in sequence.

[0037] In this invention, the polishing pad is cut and shaped to match the size of the polishing machine. Due to the presence of grooves, the polishing efficiency of the polishing pad is significantly improved. During the polishing process, when the polishing slurry flows into the grooves, the particulate silicon dioxide can fully contact the wafer, enhancing the friction removal effect and thus further improving the polishing efficiency.

[0038] In this invention, the polishing pads are required to be cleaned and packaged before shipment. The cleaning process uses high-pressure air to remove debris and burrs from the surface and grooves of the polishing pads. The polishing pads are then packaged in a customized manner to prevent the surface from being scratched, contaminated by dust, or damp during transportation.

[0039] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0040] (1) The top layer and the first adhesive layer are first bonded at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the initial material;

[0041] The top layer is made of polyurethane; the thickness of the top layer is 2-3mm and the hardness is 60-70SHA.

[0042] The first adhesive layer is a heat-sensitive double-sided adhesive; the thickness of the first adhesive layer is 50-100μm;

[0043] (2) The initial material described in step (1) and the buffer layer are bonded together for the second time at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the intermediate material;

[0044] The buffer layer is made of porous polyurethane; the thickness of the buffer layer is 0.5-1.1 mm, and the hardness is 28-32 SHA.

[0045] (3) The intermediate material described in step (2) and the second adhesive layer are bonded together for the third time at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the grinding pad;

[0046] The second adhesive layer is a pressure-sensitive double-sided adhesive; the thickness of the second adhesive layer is 80-120μm.

[0047] In a second aspect, the present invention provides an abrasive pad, which is prepared by the preparation method described in the first aspect.

[0048] Preferably, the surface flatness of the abrasive pad is 1-5μm, for example, it can be 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm or 4.5μm, etc., but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] In this invention, a polishing pad made with a buffer layer of a specific hardness range reduces the overall hardness of the polishing pad while improving its surface flatness. The polishing pad provided by this invention solves the problems of wafer surface scratches and defects during the polishing process in existing technologies, thereby improving wafer surface flatness and increasing finished product yield.

[0050] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) The preparation method provided by the present invention effectively adjusts the hardness and surface flatness of the grinding pad by using a low-hardness buffer layer and layer-by-layer hot pressing; and the preparation method is low in cost and simple in process, and is suitable for large-scale production.

[0053] (2) The grinding pad prepared by the present invention solves the problem of scratches and defects on the wafer surface during the grinding process of the prior art, thereby improving the flatness of the wafer surface and increasing the yield of finished products. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the abrasive pad prepared in Example 1;

[0055] Among them, 1-top layer, 2-first adhesive layer, 3-buffer layer, 4-second adhesive layer. Detailed Implementation

[0056] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0057] In the following examples and comparative examples, each layer of material underwent surface pretreatment before lamination to achieve a surface roughness Ra of 2-3 μm for the top layer. In the following examples and comparative examples, the top layer also underwent window-shaped fabrication before lamination.

[0058] Example 1

[0059] This embodiment provides a method for preparing an abrasive pad, the method comprising the following steps:

[0060] (1) The top layer 1 and the first adhesive layer 2 are first bonded at a temperature of 115°C and a pressure of 4 bar to obtain the initial material;

[0061] The top layer 1 is made of polyurethane; the thickness of the top layer 1 is 2.5mm and the hardness is 70SHA.

[0062] The first adhesive layer 2 is a heat-sensitive double-sided adhesive; the thickness of the first adhesive layer 2 is 70 μm;

[0063] (2) The initial material described in step (1) and the buffer layer 3 are bonded together for the second time at a temperature of 115°C and a pressure of 4 bar to obtain the intermediate material;

[0064] The buffer layer 3 is made of porous polyurethane with a pore size of 50μm; the buffer layer 3 has a thickness of 0.8mm and a hardness of 32SHA.

[0065] (3) The intermediate material described in step (2) and the second adhesive layer 4 are bonded together for the third time at a temperature of 115°C and a pressure of 4 bar to obtain the grinding pad (its structural schematic diagram is shown below). Figure 1 (as shown);

[0066] The second adhesive layer 4 is a pressure-sensitive double-sided adhesive; the thickness of the second adhesive layer 4 is 100μm;

[0067] (4) The abrasive pad described in step (3) is cut, shaped and grooved in sequence.

[0068] Example 2

[0069] This embodiment provides a method for preparing an abrasive pad, the method comprising the following steps:

[0070] (1) The top layer and the first adhesive layer are first bonded at a temperature of 145°C and a pressure of 2 bar to obtain the initial material;

[0071] The top layer is made of polyurethane; the thickness of the top layer is 3mm and the hardness is 65SHA.

[0072] The first adhesive layer is a heat-sensitive double-sided adhesive; the thickness of the first adhesive layer is 100 μm;

[0073] (2) The initial material described in step (1) and the buffer layer are bonded together for the second time at a temperature of 115°C and a pressure of 2 bar to obtain the intermediate material;

[0074] The buffer layer is made of porous polyurethane with a pore size of 50μm; the thickness of the buffer layer is 1.1mm and the hardness is 30SHA.

[0075] (3) The intermediate material described in step (2) and the second adhesive layer are bonded together for the third time at a temperature of 145°C and a pressure of 2.5 bar to obtain the grinding pad;

[0076] The second adhesive layer is a pressure-sensitive double-sided adhesive; the thickness of the second adhesive layer is 120 μm;

[0077] (4) The abrasive pad described in step (3) is cut, shaped and grooved in sequence.

[0078] Example 3

[0079] This embodiment provides a method for preparing an abrasive pad, the method comprising the following steps:

[0080] (1) The top layer and the first adhesive layer are first bonded at a temperature of 85°C and a pressure of 5 bar to obtain the initial material;

[0081] The top layer is made of polyurethane; the thickness of the top layer is 2mm and the hardness is 60SHA.

[0082] The first adhesive layer is a heat-sensitive double-sided adhesive; the thickness of the first adhesive layer is 50 μm;

[0083] (2) The initial material described in step (1) and the buffer layer are bonded together for the second time at a temperature of 95°C and a pressure of 4.5 bar to obtain the intermediate material;

[0084] The buffer layer is made of porous polyurethane with a pore size of 50μm; the thickness of the buffer layer is 0.5mm and the hardness is 28SHA.

[0085] (3) The intermediate material described in step (2) and the second adhesive layer are bonded together for the third time at a temperature of 85°C and a pressure of 5 bar to obtain a grinding pad;

[0086] The second adhesive layer is a pressure-sensitive double-sided adhesive; the thickness of the second adhesive layer is 80 μm;

[0087] (4) The abrasive pad described in step (3) is cut, shaped and grooved in sequence.

[0088] Example 4

[0089] This embodiment provides a method for preparing an abrasive pad. Except that the temperature of the first bonding in step (1), the second bonding in step (2), and the third bonding in step (3) is 55°C, all other conditions are the same as in embodiment 1.

[0090] Example 5

[0091] This embodiment provides a method for preparing an abrasive pad. Except that the temperature of the first bonding in step (1), the second bonding in step (2), and the third bonding in step (3) is 170°C, all other conditions are the same as in embodiment 1.

[0092] Example 6

[0093] This embodiment provides a method for preparing an abrasive pad. Except that the pressure of the first bonding in step (1), the second bonding in step (2), and the third bonding in step (3) is 0.5 bar, all other conditions are the same as in embodiment 1.

[0094] Example 7

[0095] This embodiment provides a method for preparing an abrasive pad. Except that the pressure of the first bonding in step (1), the second bonding in step (2), and the third bonding in step (3) is 7 bar, all other conditions are the same as in embodiment 1.

[0096] Comparative Example 1

[0097] This comparative example provides a method for preparing an abrasive pad. Except for the hardness of the buffer layer in step (2) being 40SHA, all other conditions are the same as in Example 1.

[0098] Comparative Example 2

[0099] This comparative example provides a method for preparing an abrasive pad. Except for the hardness of the buffer layer in step (2) being 23SHA, all other conditions are the same as in Example 1.

[0100] Comparative Example 3

[0101] This comparative example provides a method for preparing an abrasive pad. Except for the use of a one-step bonding molding process, in which the top layer, the first adhesive layer, the buffer layer, and the second adhesive layer are bonded together at a temperature of 115°C and a pressure of 4 bar, all other conditions are the same as in Example 1.

[0102] The abrasive pads prepared in the above embodiments and comparative examples were subjected to performance tests, and the results are shown in Table 1. The hardness was tested using a Shore A hardness tester to measure the puncture resistance of the abrasive pads.

[0103] The polishing pads prepared in the above embodiments and comparative examples were used for wafer polishing. The number of defects on the wafer surface and the yield results are shown in Table 1.

[0104] Table 1

[0105]

[0106]

[0107] As shown in Table 1:

[0108] (1) The preparation method provided by the present invention, by using a low-hardness buffer layer and layer-by-layer hot pressing bonding, not only effectively adjusts the hardness and surface flatness of the polishing pad, but also solves the problems of wafer surface scratches and defects in the existing polishing process, thereby improving the yield of finished products.

[0109] (2) Comparing Examples 1 and 4-5, it can be seen that when the temperature of hot-pressing the layers is low, the heat-sensitive double-sided adhesive cannot be effectively activated, resulting in poor bonding performance. This leads to the inability to effectively bond the top layer and the polishing pad layer. The heat-sensitive double-sided adhesive is prone to radial relative displacement during the polishing process, causing them to stick together and accumulate, resulting in a bulge on the surface of the polishing pad. This leads to defects and scratches on the wafer surface after polishing. When the temperature of hot-pressing the layers is high, the polishing pad deforms at high temperature, resulting in inconsistent surface flatness of the polishing pad. This leads to uneven height of the wafer after polishing.

[0110] (3) Comparing Examples 1 and 6-7, it can be seen that when the pressure of layer-by-layer hot pressing is low, the pressure-sensitive double-sided adhesive cannot be effectively activated, so the resulting polishing pad cannot be effectively bonded to the polishing machine, resulting in the edge of the polishing pad warping during the polishing process and inconsistent flatness in different areas of the polishing pad, thus causing problems such as inconsistent wafer surface height after polishing; when the pressure of layer-by-layer hot pressing is high, the top layer and the buffer layer undergo a certain degree of plastic deformation, their pore structure is destroyed, the structure becomes more compact, resulting in an increase in the hardness of the polishing pad. During the excessive compression process, the top layer skeleton is destroyed and detaches in the form of debris and particles, which adhere to the surface of the polishing pad, resulting in an increase in the local roughness of the polishing pad. Therefore, scratches will be caused during the polishing process, thus aggravating wafer defects and scratches.

[0111] (4) Comparison of Example 1 and Comparative Examples 1-2 shows that when the hardness of the buffer layer is high, the overall hardness of the grinding pad increases, the grinding effect is enhanced, and thus the wafer over-grinding scratch defects and other problems occur; when the hardness of the buffer layer is low, it cannot effectively buffer the pressure from the holding ring during the grinding process, which enhances the grinding effect between the wafer and the grinding particles, thus the wafer over-grinding scratch defects and other problems occur.

[0112] (5) Comparing Example 1 and Comparative Example 3, it can be seen that when the grinding pad is made by one-step bonding molding, the air between the grinding pad layers cannot be effectively removed, resulting in inconsistent flatness in different areas of the finished grinding pad. In addition, the heat insulation between the top layer and the buffer layer prevents the heat-sensitive double-sided adhesive from being effectively activated, resulting in poor interlayer bonding performance, a significant decrease in the grinding effect of the grinding pad, and defects and scratches on the product surface.

[0113] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0114] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0115] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing an abrasive pad, characterized in that, The preparation method includes the following steps: (1) The top layer and the first adhesive layer are bonded together to obtain the initial material; The temperature of the first bonding is 85-145℃; the pressure of the first bonding is 2-5 bar; (2) The initial material described in step (1) is bonded to the buffer layer for a second time to obtain the intermediate material; The buffer layer has a hardness of 28-32 SHA; the buffer layer is made of porous polyurethane. The temperature of the second bonding is 85-145℃; the pressure of the second bonding is 2-5 bar; (3) The intermediate material described in step (2) is bonded to the second adhesive layer in a third bonding process to obtain a grinding pad; The temperature of the third bonding is 85-145℃; the pressure of the third bonding is 2-5 bar.

2. The preparation method according to claim 1, characterized in that, The material of the top layer in step (1) is polyurethane.

3. The preparation method according to claim 1, characterized in that, The thickness of the top layer in step (1) is 2-3 mm.

4. The preparation method according to claim 1, characterized in that, The hardness of the top layer in step (1) is 60-70 SHA.

5. The preparation method according to claim 1, characterized in that, Step (1) The first adhesive layer is a heat-sensitive double-sided adhesive.

6. The preparation method according to claim 1, characterized in that, Step (1) The thickness of the first adhesive layer is 50-100 μm.

7. The preparation method according to claim 1, characterized in that, The porous polyurethane in step (2) has a pore size of 50-100 μm.

8. The preparation method according to claim 1, characterized in that, The thickness of the buffer layer in step (2) is 0.5-1.1 mm.

9. The preparation method according to claim 1, characterized in that, Step (3) The second adhesive layer is pressure-sensitive double-sided adhesive.

10. The preparation method according to claim 1, characterized in that, In step (3), the thickness of the second adhesive layer is 80-120 μm.

11. The preparation method according to claim 1, characterized in that, Step (3) after obtaining the grinding pad also includes cutting and shaping and processing grooves in sequence.

12. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) The top layer and the first adhesive layer are first bonded at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the initial material; The top layer is made of polyurethane; the thickness of the top layer is 2-3mm and the hardness is 60-70SHA. The first adhesive layer is a heat-sensitive double-sided adhesive; the thickness of the first adhesive layer is 50-100μm; (2) The initial material described in step (1) and the buffer layer are bonded together for the second time at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the intermediate material; The buffer layer is made of porous polyurethane; the thickness of the buffer layer is 0.5-1.1 mm, and the hardness is 28-32 SHA. (3) The intermediate material described in step (2) and the second adhesive layer are bonded together for the third time at a temperature of 85-145℃ and a pressure of 2-5 bar to obtain the grinding pad; The second adhesive layer is a pressure-sensitive double-sided adhesive; the thickness of the second adhesive layer is 80-120μm.

13. An abrasive pad, characterized in that, The abrasive pad is prepared by the preparation method according to any one of claims 1-12.

14. The abrasive pad according to claim 13, characterized in that, The surface flatness of the abrasive pad is 1-5 μm.

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