Polishing pad, preparation method thereof and chemical mechanical polishing equipment

Abstract

The invention provides a polishing pad, a preparation method of the polishing pad and chemical mechanical polishing equipment. The waterproof buffer layer is arranged on one side, in the thickness direction, of the polishing layer, and the waterproof buffer layer is at least formed by compounding thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent; and the back adhesive layer is arranged on one side, back to the polishing layer, of the waterproof buffer layer. According to the polishing pad, the waterproof buffer layer is formed by compounding the thermoplastic polyurethane, the polyrotaxane and the anti-hydrolysis agent, the polyrotaxane enables the waterproof buffer layer to maintain a stable buffer effect, shear stress borne by the adhesive layer is reduced, and the anti-hydrolysis agent can improve the chemical corrosion resistance of the polishing pad. The waterproof buffer layer is arranged between the polishing layer and the back adhesive layer, so that the polishing liquid absorbed by the polishing layer can be prevented from being transferred to the back adhesive layer, and the back adhesive layer is prevented from being corroded and losing efficacy. According to the polishing pad, the reliability can be improved, the service life can be prolonged, and the polishing cost can be reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a polishing pad and a preparation method thereof, and a chemical mechanical polishing device. Background Art

[0002] Chemical Mechanical Polishing (CMP) is the mainstream technology for polishing wafers, which can achieve ultra-high flatness on the wafer surface. As one of the main consumables in the CMP process, the polishing pad has the functions of storing and supplying polishing liquid, removing processing residual materials and transmitting mechanical loads. The service life of the polishing pad seriously affects the cost of CMP.

[0003] The existing composite polishing pad is usually composed of a polishing layer, a buffer layer and a back adhesive layer. The buffer layer and the polishing layer are generally bonded by a pressure-sensitive adhesive or a hot-melt adhesive. When in use, the polishing pad is bonded to the polishing disc by the adhesive of the back adhesive layer.

[0004] However, during the CMP process, the shear force on the adhesive layer of the polishing pad and the corrosion of the polishing liquid on the adhesive layer can easily cause the adhesive of the adhesive layer to fail, thereby causing the polishing pad to delaminate and end its life. Summary of the invention

[0005] In view of the above problems, the present application provides a polishing pad and a preparation method thereof, and a chemical mechanical polishing device, which can improve the reliability and service life of the polishing pad and also help reduce the polishing cost.

[0006] In the first aspect, the present application provides a polishing pad, comprising: a polishing layer; a waterproof buffer layer, arranged on one side of the polishing layer along the thickness direction, the waterproof buffer layer being composited with at least thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent; and a back adhesive layer, arranged on the side of the waterproof buffer layer facing away from the polishing layer.

[0007] In some embodiments, the anti-hydrolysis agent includes at least one of polycarbodiimide, epoxy compounds, and oxazoline, and / or the waterproof buffer layer further includes thermosetting polyurethane.

[0008] In some embodiments, the adhesive layer includes at least one of an acrylic-based adhesive and a rubber-based adhesive; and / or the polishing layer is composited by thermoplastic polyurethane and non-woven fabric.

[0009] In some embodiments, the hardness of the polishing layer is 60A-85A; and / or the thickness of the polishing layer is 0.5mm-5mm; and / or the thickness of the waterproof buffer layer is 1mm-7mm.

[0010] A second aspect of the present application provides a method for preparing a polishing pad, comprising the following steps:

[0011] preparing a polishing layer;

[0012] Casting a buffer layer precasting liquid including thermoplastic polyurethane, an anti-hydrolysis agent, polyrotaxane and a solvent onto one side of the polishing layer in the thickness direction to obtain a waterproof buffer layer;

[0013] The waterproof buffer layer is subjected to back-adhesive treatment to obtain a back-adhesive layer, thereby obtaining the polishing pad.

[0014] In some embodiments, the buffer layer precasting liquid includes, by weight: 100-150 parts of thermoplastic polyurethane, 10-30 parts of polyrotaxane, and 5-10 parts of anti-hydrolysis agent.

[0015] In some embodiments, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0016] In some embodiments, after pouring the buffer layer pre-casting liquid onto the polishing layer, the method further includes: gelling at a first preset temperature for a first preset time to form the waterproof buffer layer.

[0017] In some embodiments, the first preset temperature is: 60°C-80°C; and / or the first preset time is: 60min-100min.

[0018] In some embodiments, the preparation of the polishing layer includes: impregnating a polyurethane slurry including a thermoplastic polyurethane resin and a solvent into a non-woven fabric to obtain an impregnated sample; placing the impregnated sample in water for pre-coagulation for a second preset time; placing the pre-coagulated impregnated sample in a drying device and drying it at a second preset temperature for a third preset time to obtain the polishing layer.

[0019] In some embodiments, the impregnated sample comprises, by mass: 80-100 parts of thermoplastic polyurethane and 30-60 parts of solvent; and / or, the second preset time is 20min-60min; and / or, the second preset temperature is 80℃-120℃; and / or, the third preset time is 70min-100min.

[0020] A third aspect of the present application provides a chemical mechanical polishing device, comprising the polishing pad of the first aspect.

[0021] The polishing pad and its preparation method, as well as the chemical mechanical polishing equipment provided by the present application, have a waterproof buffer layer composed of a thermoplastic polyurethane, a polyrotaxane and an anti-hydrolysis agent, wherein the polyrotaxane enables the waterproof buffer layer to maintain a stable buffering effect, reduces the shear stress on the adhesive layer, and the anti-hydrolysis agent can improve its chemical corrosion resistance. By arranging the waterproof buffer layer between the polishing layer and the back adhesive layer, the waterproof buffer layer can be used to block the transfer of the polishing liquid absorbed by the polishing layer to the back adhesive layer, thereby preventing the back adhesive layer from being corroded and failing. In this way, the reliability and service life of the polishing pad can be significantly improved, and it is also beneficial to reduce the polishing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a schematic diagram of the structure of the polishing pad according to an embodiment of the present application.

[0024] Description of reference numerals:

[0025] 100-polishing pad;

[0026] 101 - polishing layer; 102 - waterproof buffer layer; 103 - adhesive layer. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of this application.

[0028] Chemical Mechanical Polishing (CMP) technology is the mainstream technology for polishing wafers, which can achieve ultra-high flatness on the wafer surface. As one of the main consumables in the CMP process, the polishing pad has the functions of storing and supplying polishing liquid, removing processing residual materials and transmitting mechanical loads. The service life of the polishing pad seriously affects the cost of CMP. Existing composite polishing pads are usually composed of a polishing layer, a buffer layer and a backing layer. The buffer layer and the polishing layer are generally bonded by a pressure-sensitive adhesive or a hot-melt adhesive. When in use, the polishing pad is bonded to the polishing disk by the adhesive of the backing layer. However, during the CMP process, the shear force on the backing layer of the polishing pad and the corrosion of the backing layer by the polishing liquid can easily cause the adhesive of the backing layer to fail, resulting in the delamination of the polishing pad and the end of its service life.

[0029] In view of this, the present application provides a polishing pad and a preparation method thereof, and a chemical mechanical polishing device, wherein the waterproof buffer layer is composited by thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent, wherein the polyrotaxane enables the waterproof buffer layer to maintain a stable buffering effect, reduces the shear stress on the adhesive layer, and the anti-hydrolysis agent can improve its chemical corrosion resistance. By arranging the waterproof buffer layer between the polishing layer and the back adhesive layer, the waterproof buffer layer can be used to block the transfer of the polishing liquid absorbed by the polishing layer to the back adhesive layer, thereby preventing the back adhesive layer from being corroded and failing. In this way, the reliability and service life of the polishing pad can be significantly improved, and it is also beneficial to reduce the polishing cost.

[0030] Combine the following Figure 1 The polishing pad 100 provided in the embodiment of the present application is described in detail.

[0031] The polishing pad 100 of the present embodiment may include a polishing layer 101 , a waterproof buffer layer 102 , and a back adhesive layer 103 which are stacked along a thickness direction of the polishing pad 100 .

[0032] Among them, the polishing layer 101 has strong wear resistance, and the polishing layer 101 is mainly used to transfer mechanical load to the workpiece (such as a wafer) to remove excess material on the surface of the workpiece. In addition, since polishing liquid is usually added during the CMP (chemical mechanical polishing) process, the polishing layer 101 can be constructed to have pore structures of different sizes on its surface. These pore structures play a role in transporting the polishing liquid, ensuring chemical corrosion and removing waste during the polishing process. Exemplarily, the polishing layer 101 can be composed of at least one of thermoplastic polyurethane, non-woven fabric and synthetic leather.

[0033] The waterproof buffer layer 102 is disposed on one side of the polishing layer 101 along the thickness direction (eg Figure 1The waterproof buffer layer 102 may be in direct contact with the polishing layer 101, or the waterproof buffer layer 102 and the polishing layer 101 may be provided with other intermediate layers, which is not limited in this embodiment.

[0034] The adhesive layer 103 is disposed on the side of the waterproof buffer layer 102 facing away from the polishing layer 101 (eg Figure 1 The back adhesive layer 103 can bond and fix the polishing pad 100 to the polishing plate of the chemical mechanical polishing equipment to ensure the stability of the polishing pad 100 during the CMP process.

[0035] The waterproof buffer layer 102 can support the polishing layer 101 during the polishing process, as well as absorb and disperse the impact applied to the polishing layer 101. In addition, since the waterproof buffer layer 102 has a water-blocking effect, it can prevent the polishing liquid absorbed by the polishing layer 101 from transferring to the back glue layer 103, thereby preventing the back glue layer 103 from being corroded by the polishing liquid and becoming ineffective.

[0036] It should be noted that the waterproof buffer layer 102 in this embodiment is at least composed of thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent.

[0037] The thermoplastic polyurethane in the waterproof buffer layer 102 can ensure that the waterproof buffer layer 102 has a certain elasticity.

[0038] Polyrotaxane is a high molecular polymer material with good elasticity. It can utilize the free movement (physical effect) of the cyclic molecules in the polyrotaxane to improve the partial reversibility and buffering performance of the polymer material. When the recovery performance of the thermoplastic polyurethane decreases and the compression permanent deformation increases, the polyrotaxane with a smaller compression permanent deformation can provide strong support for the thermoplastic polyurethane and help the thermoplastic polyurethane to recover, thereby helping the polishing pad 100 to maintain its elastic properties. In other words, by using polyrotaxane, the waterproof buffer layer 102 can maintain a stable and continuous buffering effect and reduce the shear stress on the back adhesive layer 103.

[0039] Adding an anti-hydrolysis agent to the waterproof buffer layer 102 can improve its chemical corrosion resistance. For example, the anti-hydrolysis agent can be polycarbodiimide, a compound whose molecule contains a functional group (—N=C=N—), so that it can react with the carboxylic acid produced after the hydrolysis of the thermoplastic polyurethane to form urea, thereby preventing the catalytic effect of the carboxylic acid on the hydrolysis, reducing the hydrolysis reaction of the thermoplastic polyurethane, so as to ensure the stability of the thermoplastic polyurethane and improve the corrosion resistance of the waterproof buffer layer 102.

[0040] For example, the composite material formed by thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent can be cast on the polishing layer 101 to prepare the waterproof buffer layer 102. In this way, the waterproof buffer layer 102 of this embodiment can form a dense void-free structure to effectively block the polishing liquid from penetrating into the adhesive layer 103, and prevent the adhesive layer 103 from being corroded and ineffective by the polishing liquid. In other words, the waterproof buffer layer 102 of this embodiment is cast, and its adhesion on the polishing layer 101 is stronger and its density is higher.

[0041] In the polishing pad 100 of the embodiment of the present application, the waterproof buffer layer 102 is composited by thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the polyrotaxane enables the waterproof buffer layer 102 to maintain a stable buffering effect, reducing the shear stress on the adhesive layer, and the anti-hydrolysis agent can improve its chemical corrosion resistance. By arranging the waterproof buffer layer 102 between the polishing layer 101 and the adhesive layer 103, the waterproof buffer layer 102 can be used to block the polishing liquid absorbed by the polishing layer 101 from transferring to the adhesive layer 103, preventing the adhesive layer 103 from being corroded and failing. In this way, the reliability and service life of the polishing pad 100 can be significantly improved, and it is also beneficial to reduce the polishing cost.

[0042] In some embodiments, the thickness of the waterproof buffer layer 102 is 1 mm-7 mm. For example, the thickness of the waterproof buffer layer 102 can be 1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.1 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm or 7 mm. Of course, the present application does not limit this, and the thickness of the waterproof buffer layer 102 can be flexibly selected within the above range as needed. In this way, it is avoided that when the thickness of the waterproof buffer layer 102 is too small, for example, less than 1 mm, the water blocking effect and the buffering effect during polishing are poor, and it is also avoided that when the thickness of the waterproof buffer layer 102 is too large, for example, greater than 7 mm, the larger thickness cannot significantly improve the water blocking effect. Waste of materials caused. In summary, by ensuring that the thickness of the waterproof buffer layer 102 is within the range of 1 mm-7 mm, the waterproof effect can be taken into account while ensuring the buffer support effect, thereby improving the service life of the polishing pad 100.

[0043] In some embodiments, the waterproof buffer layer 102 is cast on the polishing layer 101. For example, thermoplastic polyurethane, anti-hydrolysis agent and polyrotaxane can be dissolved in a solvent according to a certain mass ratio, adjusted to a certain viscosity to obtain a buffer layer pre-casting liquid, and then the buffer layer pre-casting liquid is cast on the surface of one side of the polishing layer 101, and then gelled to obtain the waterproof buffer layer 102. In this way, the casting method is conducive to obtaining a non-porous and highly dense waterproof buffer layer 102, so as to better isolate the corrosive polishing liquid for the back glue layer 103, and the casting method is relatively simple and easy to process.

[0044] In some embodiments, the anti-hydrolysis agent may include at least one of polycarbodiimide, epoxy compound, and oxazoline. For example, the anti-hydrolysis agent may include only polycarbodiimide, may include only epoxy compound, or may include only oxazoline. In addition, the anti-hydrolysis agent may also be composed of any two or all of polycarbodiimide, epoxy compound, and oxazoline. In this way, the chemical corrosion resistance of the waterproof buffer layer 102 can be improved.

[0045] In some embodiments, the waterproof buffer layer 102 may further include thermosetting polyurethane. Specifically, in the process of preparing the waterproof buffer layer 102, a certain amount of thermosetting polyurethane may be mixed into the composite material of polyrotaxane, anti-hydrolysis agent and thermoplastic polyurethane. Since thermosetting polyurethane has better heat resistance and deformation resistance than thermoplastic polyurethane, mixing an appropriate amount of thermosetting polyurethane may enhance the heat resistance and deformation resistance of the waterproof buffer layer 102.

[0046] In some embodiments, the adhesive layer 103 may include at least one of an acrylic adhesive or a rubber adhesive. For example, the adhesive layer 103 may include only an acrylic adhesive, or may also include only a rubber adhesive. In this way, the adhesive layer 103 may have a high viscosity to improve the connection stability between the polishing pad 100 and the polishing disc.

[0047] In some embodiments, the polishing layer 101 is composed of a composite of thermoplastic polyurethane and non-woven fabric, wherein the thermoplastic polyurethane material has strong wear resistance, tear strength and acid and alkali corrosion resistance, and its surface microporous structure can soften and roughen the surface of the workpiece, and keep the abrasive particles in the polishing liquid to achieve efficient flattening processing; and the non-woven fabric has good water permeability and strong ability to accommodate the polishing liquid. That is to say, by compounding the polishing layer 101 of thermoplastic polyurethane and non-woven fabric, the polishing layer 101 can have sufficient wear resistance and can absorb and store the polishing liquid well, which is conducive to improving the polishing effect of the workpiece.

[0048] In some embodiments, the hardness of the polishing layer 101 is 60A-85A, for example, the hardness of the polishing layer 101 can be 60A, 65A, 70A, 75A, 80A or 85A, of course, the present application is not limited to this, and the hardness of the polishing layer 101 can be reasonably set according to actual needs. In this way, it can be ensured that the polishing layer 101 has sufficient hardness to efficiently remove excess material on the workpiece.

[0049] In some embodiments, the thickness of the polishing layer 101 is 0.5 mm-5 mm, for example, the thickness of the polishing layer 101 can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, of course, the present application is not limited to this, and the thickness of the polishing layer 101 can be reasonably set according to actual needs. In this way, the polishing layer 101 can have sufficient structural stability and the ability to absorb and store polishing liquid.

[0050] A second aspect of the present application provides a method for preparing a polishing pad 100, comprising the following steps:

[0051] S101, preparing a polishing layer 101;

[0052] Specifically, the polishing layer 101 is composited from thermoplastic polyurethane and non-woven fabric.

[0053] S102, pouring a buffer layer precasting liquid including thermoplastic polyurethane, an anti-hydrolysis agent, polyrotaxane and a solvent onto the polishing layer 101 to obtain a waterproof buffer layer 102;

[0054] S103 , performing adhesive treatment on the waterproof buffer layer 102 to obtain a polishing pad 100 having an adhesive layer 103 .

[0055] The method for preparing the polishing pad 100 of the embodiment of the present application adopts thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent composite material to be cast into the polishing layer 101 to prepare the waterproof buffer layer 102, so that the void-free structure formed by the waterproof buffer layer 102 can block the polishing liquid from penetrating into the back glue layer 103, and prevent the back glue layer 103 from being corroded and ineffective by the polishing liquid. The anti-hydrolysis agent in the waterproof buffer layer 102 can improve the corrosion resistance of the waterproof buffer layer 102. The polyrotaxane material in the waterproof buffer layer 102 can quickly restore the elasticity of the thermoplastic polyurethane, maintain the stable buffering effect of the buffer layer, and reduce the shear stress on the glue layer. In this way, the prepared polishing pad 100 has good structural stability and service life, which is conducive to improving the polishing efficiency and reducing the cost of the chemical mechanical polishing process.

[0056] In some embodiments, the buffer layer precasting liquid may include, by mass, 100-150 parts of thermoplastic polyurethane, 10-30 parts of polyrotaxane, and 5-10 parts of anti-hydrolysis agent. That is, the ratio of the mass M1 of thermoplastic polyurethane, the mass M2 of polyrotaxane, and the mass M3 of anti-hydrolysis agent is: M1:M2:M3=(100-150):(10-30):(5-10). By mixing thermoplastic polyurethane, polyrotaxane, and anti-hydrolysis agent in the above mass ratio to prepare the waterproof buffer layer 102, it can be ensured that the waterproof buffer layer 102 has sufficient buffering support performance and water-blocking and anti-corrosion capabilities.

[0057] In some embodiments, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone. For example, the solvent may be only N,N-dimethylformamide, only N,N-dimethylacetamide, or only N-methylpyrrolidone. Of course, the solvent may also be any two or all of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone. In this way, it can be ensured that the solvent has a good solubility for thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, thereby improving the mixing uniformity of the components such as thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent.

[0058] In some embodiments, after pouring the buffer layer pre-casting liquid onto the polishing layer 101 , the method further includes: gelling at a first preset temperature for a first preset time to form the waterproof buffer layer 102 .

[0059] It can be understood that, since the buffer layer precasting liquid is in a fluid state with a certain fluidity, it needs to be gelled at a certain temperature, namely, a first preset temperature, so as to form a non-porous and dense waterproof buffer layer 102 .

[0060] In some embodiments, the first preset temperature is: 60°C-80°C, for example, the first preset temperature can be 60°C, 61°C, 63°C, 65°C, 68°C, 70°C, 72°C, 75°C, 77°C or 80°C, of ​​course, the present application does not limit this, in order to ensure the structural stability of the waterproof buffer layer 102 after gelation and the reliability of the connection with the polishing layer 101, the first preset temperature can be reasonably selected within the above range according to actual needs. In this way, on the one hand, it is prevented that the gelation rate is too low when the first preset temperature is too low, for example, below 60°C, and on the other hand, it is prevented that the first preset temperature is too high, for example, below 80°C, and the solvent evaporates too quickly and too much, which is not conducive to forming a dense structure.

[0061] In some embodiments, the first preset time is: 60min-100min, for example, the first preset time can be 60min, 63min, 65min, 68min, 70min, 75min, 78min, 80min, 81min, 83min, 85min, 88min, 90min, 92min, 94min, 95min, 97 min, 99min or 100min. Of course, the present application is not limited to this, and the first preset temperature can be reasonably selected within the above range according to actual needs to ensure the structural stability of the waterproof buffer layer 102 after gelation and the reliability of connection with the polishing layer 101.

[0062] In some embodiments, preparing the polishing layer 101, that is, step S101, may include the following steps:

[0063] S1011, impregnating a polyurethane slurry including a thermoplastic polyurethane resin and a solvent into a non-woven fabric to obtain an impregnated sample;

[0064] S1012, placing the immersed sample in water for pre-coagulation for a second preset time;

[0065] S1013 , placing the pre-condensed impregnated sample in a drying device and drying it at a second preset temperature for a third preset time to obtain the polishing layer 101 .

[0066] By dissolving thermoplastic polyurethane resin in a solvent to form a polyurethane slurry, the polyurethane slurry can be better impregnated into the non-woven fabric; and pre-condensing the polyurethane slurry and the non-woven fabric in water can improve the bonding effect of the polyurethane slurry and the non-woven fabric; finally, the impregnated sample is dried to obtain a polishing layer 101 with a stable structure.

[0067] In some embodiments, the impregnated sample includes 80-100 parts of thermoplastic polyurethane and 30-60 parts of solvent in parts by mass. That is, the ratio of the mass M11 of the thermoplastic polyurethane to the mass M12 of the solvent in the polyurethane slurry is: M11:M12=(80-100):(30-60). By mixing the thermoplastic polyurethane and the solvent in the above mass ratio to prepare the polishing layer 101, it can be ensured that the thermoplastic polyurethane is well dissolved so as to be better impregnated into the non-woven fabric.

[0068] In some embodiments, the second preset time is 20min-60min, for example, the second preset time can be 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min or 60min, of course, the present application does not limit this, and the second preset time is reasonably taken within the above range according to actual needs. In this way, on the one hand, it is helpful to avoid the second preset time being too short, for example, less than 20min, resulting in poor pre-condensation effect, and on the other hand, it is helpful to avoid the second preset time being too long, for example, more than 60min, resulting in too low preparation efficiency of the polishing layer 101.

[0069] In some embodiments, the second preset temperature is 80° C.-120° C. For example, the second preset temperature may be 80° C., 85° C., 90° C., 95° C., 100° C., 105° C., 110° C., 115° C. or 120° C. In this way, on the one hand, it is helpful to avoid the second preset temperature being too low, for example, below 80° C., resulting in too low drying efficiency, and on the other hand, it is helpful to avoid the second preset temperature being too high, for example, above 120° C., which is not conducive to the structural stability of the polishing layer 101.

[0070] In some embodiments, the third preset time is 70 min-100 min, for example, the third preset time can be 70 min, 75 min, 80 min, 85 min, 90 min, 95 min or 100 min. In this way, on the one hand, it is helpful to avoid the situation that the drying time is too short, for example, less than 70 min, the polishing pad 100 is not fully dried and the structural stability is poor. On the other hand, it is helpful to avoid the situation that the drying time is too long, for example, more than 100 min, the drying efficiency is too low, resulting in low preparation efficiency.

[0071] In some embodiments, before the back glue treatment is performed, the following may be included: grinding the surface of the polishing layer 101 and the surface of the waterproof buffer layer 102 on the side facing away from the polishing layer 101. The grinding step improves the flatness of the surface of the polishing layer 101 and the surface of the waterproof buffer layer 102 on the side facing away from the polishing layer 101, and when the back glue layer 103 is provided, the adhesion between the back glue layer 103 and the waterproof buffer layer 102 can be increased, which is beneficial to improving the structural stability and service life of the buffer pad 100.

[0072] In some embodiments, after the back glue treatment, the polishing pad 100 is also subjected to cutting and grooving. Specifically, the polishing pad 100 can be cut into a target shape such as a circle, and grooves can be carved on the surface of the polishing layer 101. The grooves can be used as spaces for accommodating polishing liquid, waste, and exhaust and heat dissipation. In this way, the polishing pad 100 obtained can be used for polishing workpieces such as wafers and optical glass.

[0073] The chemical mechanical polishing equipment provided in the third embodiment of the present application includes the above-mentioned polishing pad 100.

[0074] The chemical mechanical polishing equipment of this embodiment is provided with the polishing pad 100 in the above embodiment. Since the polishing pad 100 has high reliability and long service life, it is beneficial to improve the polishing quality of the chemical mechanical polishing equipment and reduce the polishing cost.

[0075] Some specific embodiments of the polishing pad 100 of the present application and methods for preparing the same are described below.

[0076] Example 1

[0077] The polishing pad 100 includes a polishing layer 101, a waterproof buffer layer 102 and a back adhesive layer 103 from top to bottom, wherein the polishing layer 101 is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer 102 is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer 103 is selected from at least one of an acrylic adhesive or a rubber-based adhesive. The hardness of the polishing layer 101 is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer 102 is 5mm.

[0078] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer 101; ④ 150 parts of thermoplastic polyurethane, 10 parts of polyrotaxane, and 5 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 12000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer 101, and gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a strong recovery and corrosion-resistant polishing pad 100.

[0079] Example 2 (Compared with Example 1, the amount of polyrotaxane is increased)

[0080] The polishing pad 100 includes a polishing layer 101, a waterproof buffer layer 102 and a back adhesive layer 103 from top to bottom. The polishing layer 101 is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer 102 is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer 103 is selected from at least one of acrylic adhesive or rubber adhesive. The hardness of the polishing layer 101 is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer 102 is 5mm.

[0081] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer 101; ④ 150 parts of thermoplastic polyurethane, 30 parts of polyrotaxane, and 5 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 12000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer 101, and then gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a strong recovery and corrosion-resistant polishing pad 100.

[0082] Example 3 (Compared with Example 2, the viscosity of the buffer layer precasting liquid is reduced)

[0083] The polishing pad 100 includes a polishing layer 101, a waterproof buffer layer 102 and a back adhesive layer 103 from top to bottom. The polishing layer 101 is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer 102 is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer 103 is selected from at least one of acrylic adhesive or rubber adhesive. The hardness of the polishing layer 101 is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer 102 is 5mm.

[0084] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer 101; ④ 150 parts of thermoplastic polyurethane, 30 parts of polyrotaxane, and 5 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 8000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer 101, and then gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a strong recovery and corrosion-resistant polishing pad 100.

[0085] Example 4 (Compared with Example 3, the amount of anti-hydrolysis agent polycarbodiimide is increased)

[0086] The polishing pad 100 includes a polishing layer 101, a waterproof buffer layer 102 and a back adhesive layer 103 from top to bottom. The polishing layer 101 is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer 102 is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer 103 is selected from at least one of acrylic adhesive or rubber adhesive. The hardness of the polishing layer 101 is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer 102 is 5mm.

[0087] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer 101; ④ 150 parts of thermoplastic polyurethane, 30 parts of polyrotaxane, and 10 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 8000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer 101, and then gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a strong recovery and corrosion-resistant polishing pad 100.

[0088] Comparative Example 1 (Compared with Example 4, the buffered precasting liquid does not use polyrotaxane)

[0089] The polishing pad is composed of a polishing layer, a waterproof buffer layer and a back adhesive layer from top to bottom. The polishing layer is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer is selected from at least one of acrylic adhesive or rubber-based adhesive. The hardness of the polishing layer is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer is 5mm.

[0090] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer; ④ 150 parts of thermoplastic polyurethane and 10 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 8000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer, and then gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a polishing pad.

[0091] Comparative Example 2 (Compared with Example 4, the buffer layer precasting liquid does not use an anti-hydrolysis agent)

[0092] The polishing pad is composed of a polishing layer, a waterproof buffer layer and a back adhesive layer from top to bottom. The polishing layer is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer is selected from at least one of acrylic adhesive or rubber-based adhesive. Further, the hardness of the polishing layer is 70A and the thickness is 5mm. Further, the thickness of the waterproof buffer layer is 5mm.

[0093] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N,N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into non-woven fabric, excess solution on the surface of the non-woven fabric is scraped off, and the non-woven fabric is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer; ④ 150 parts of thermoplastic polyurethane and 30 parts of polyrotaxane are dissolved in a solvent, and its viscosity is adjusted to 8000cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is cast onto the polishing layer, and then gelled at 60°C for 100 minutes; ⑥ the sample obtained in step ⑤ is polished, back-glued, cut and grooved to obtain a polishing pad.

[0094] Comparative Example 3 (Compared with Example 4, the polishing layer and the waterproof buffer layer are bonded by an adhesive)

[0095] The polishing pad is composed of a polishing layer, an adhesive, a waterproof buffer layer and a back adhesive layer from top to bottom. The polishing layer is composited with thermoplastic polyurethane and non-woven fabric, the waterproof buffer layer is composited with thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent, and the back adhesive layer is selected from at least one of acrylic adhesive or rubber adhesive. The hardness of the polishing layer is 70A and the thickness is 5mm. The thickness of the waterproof buffer layer is 5mm.

[0096] The preparation process is as follows: ① 100 parts of thermoplastic polyurethane resin and 60 parts of N, N-dimethylformamide are prepared into polyurethane slurry, and the thermoplastic polyurethane resin has a molecular weight of 30,0000; ② the polyurethane slurry obtained in step ① is impregnated into a non-woven fabric, and the excess solution on the surface of the non-woven fabric is scraped off to obtain an impregnated sample, and the impregnated sample is placed in water for pre-condensation for 60 minutes; ③ the impregnated sample after pre-condensation in step ② is placed in a 120°C oven for drying for 100 minutes to obtain a polishing layer; ④ 150 parts of thermoplastic polyurethane, 30 parts of polyrotaxane, and 10 parts of polycarbodiimide are dissolved in a solvent, and the viscosity thereof is adjusted to 8000 cP to obtain a buffer layer pre-casting liquid; ⑤ the buffer layer pre-casting liquid obtained in step ④ is scraped onto a glass plate, and then gelled at 60°C for 100 minutes to obtain a waterproof buffer layer; ⑥ the polishing layer is bonded to the waterproof buffer layer obtained in step ⑤ using an acrylic adhesive, and then polished, back-glued, cut and grooved to obtain a polishing pad.

[0097] The test methods and results of the above embodiments and comparative examples are as follows:

[0098] (1) Polishing pad peeling performance test: GB / T 2792 180° peeling test was adopted. The polishing pads of the above-mentioned embodiments and comparative examples were immersed in the polishing liquid for 40 hours. The peeling strength change between the waterproof buffer layer and the back adhesive layer before and after immersion was tested. The sample width was 25 mm, the peeling length was 25 mm, and the peeling speed was 300 mm / min.

[0099]

[0100] According to the above table, in combination with Example 4 and Comparative Example 3, since the polishing layer and the waterproof buffer layer are bonded by an adhesive in Comparative Example 3, the polishing pad forms a four-layer structure, and the peel strength between the waterproof buffer layer and the back adhesive layer is significantly reduced. Therefore, the present application arranges the waterproof buffer layer on the polishing layer by casting, so that the connection performance between the waterproof buffer layer and the polishing layer is greatly improved, the peel strength is increased, and since the waterproof buffer layer has good waterproof performance, the corrosion of the back adhesive layer by the polishing liquid is reduced.

[0101] Combining Examples 3 and 4, it can be found that the peel strength between the waterproof buffer layer and the back adhesive layer of the polishing pad in Example 4 before and after being immersed in the polishing liquid is higher than that of Example 3. Therefore, adding the anti-hydrolysis agent is beneficial to improving the waterproof performance of the waterproof buffer layer and reducing the corrosion of the back adhesive layer by the polishing liquid.

[0102] (2) Polishing pad shear strength test: The polishing pads of the above embodiments and comparative examples were soaked in the polishing liquid for 40 hours, and the shear strength changes between the waterproof buffer layer and the adhesive layer before and after soaking were tested. The width of the bonding area of ​​the sample was 25 mm, the length was 30 mm, and the tensile rate was 50 mm / min.

[0103]

[0104] According to the above table, in combination with Examples 1-4 and Comparative Examples 1-3, since the waterproof buffer layer of Comparative Example 1 does not use polyrotaxane, the buffering capacity is reduced, and Comparative Example 2 does not use an anti-hydrolysis agent, resulting in a decrease in corrosion resistance. In Comparative Example 3, since an adhesive is used to bond the polishing layer and the waterproof buffer layer, the polishing pad includes a four-layer structure including a polishing layer, an adhesive, a waterproof buffer layer, and a back adhesive layer. Any of the above factors will lead to a decrease in the shear strength between the waterproof buffer layer and the back adhesive layer. Therefore, the present application arranges the waterproof buffer layer composed of thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent in the polishing layer in a casting molding manner, which is beneficial to improve the waterproof performance of the waterproof buffer layer and reduce the corrosion of the polishing liquid to the back adhesive layer. In addition, it can be seen from the combination of Examples 1 and 2 that increasing the amount of polyrotaxane is beneficial to the waterproof buffer layer to maintain its elastic properties, maintain a stable and continuous buffering effect, and reduce the shear stress on the back adhesive layer.

[0105] (3) Polishing pad hardness test: The hardness test of the polishing pads of the above-mentioned embodiments and comparative examples was carried out in accordance with the standard "GB / T 2411-2008 Determination of indentation hardness (Shore A hardness) of plastics and hard rubber using a hardness tester".

[0106]

[0107] According to the above table, combined with Examples 1 and 2, it can be seen that increasing the amount of polyrotaxane will increase the hardness of the polishing pad, combined with Examples 2 and 3, it can be seen that reducing the viscosity of the buffer layer precasting liquid will increase the hardness of the polishing pad, and combined with Examples 3 and 4, it can be seen that increasing the amount of the anti-hydrolysis agent polycarbodiimide will reduce the hardness of the polishing pad.

[0108] In combination with Example 4 and Comparative Examples 1-3, since the waterproof buffer layer of Comparative Example 1 does not use polyrotaxane, and Comparative Example 2 does not use an anti-hydrolysis agent, the polishing pad of Comparative Example 3 includes a four-layer structure including a polishing layer, an adhesive, a waterproof buffer layer and a back adhesive layer. Any of the above factors will cause the hardness of the polishing pad to increase, and a polishing pad with too high a hardness is not conducive to polishing the wafer.

[0109] (4) Polishing pad compression test: According to the test standard JISL1021, use a SCHOPPER type thickness tester, the pressure surface is 1cm, and the initial load is 100g / cm 2 , the thickness t0 after pressing for 30s, and then measured at the final pressure of 1120g / cm 2 , the thickness t1 after pressurization for 5 minutes, removing all loads, compression rate (%) = 100×(t0-t1) / t1.

[0110]

[0111] According to the above table, in combination with Example 4 and Comparative Examples 1-3, since the waterproof buffer layer of Comparative Example 1 does not use polyrotaxane, Comparative Example 2 does not use an anti-hydrolysis agent, and the polishing pad of Comparative Example 3 includes a four-layer structure including a polishing layer, an adhesive, a waterproof buffer layer and a back adhesive layer, any of the above factors will lead to a decrease in the compression rate of the polishing pad and a weakening of the buffering performance. Therefore, the present application arranges a waterproof buffer layer composed of a composite of thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent on the polishing layer by casting, which is beneficial to improving the compression rate and buffering performance of the waterproof buffer layer.

[0112] (5) Polishing pad life test: The polishing experiment was carried out using a CMP test machine model TAP-402S, using ANJIAEPU3061A polishing liquid and a polishing pad diameter of 550 mm. The polishing parameters were as follows: polishing pressure 1.5 psi, polishing speed 50-60 rpm, polishing liquid flow rate 300 mL / min, and polishing time 60 s.

[0113]

[0114] According to the above table, in combination with Examples 1-4 and Comparative Examples 1-3, since the waterproof buffer layer of Comparative Example 1 does not use polyrotaxane, the waterproof buffer layer of Comparative Example 2 does not use an anti-hydrolysis agent, and the polishing pad of Comparative Example 3 includes a four-layer structure including a polishing layer, an adhesive, a waterproof buffer layer and a back adhesive layer, any of the above factors will lead to a shortened service life of the polishing pad. Therefore, the present application arranges a waterproof buffer layer composed of a composite of thermoplastic polyurethane, polyrotaxane and an anti-hydrolysis agent on the polishing layer, wherein the polyrotaxane enables the waterproof buffer layer to maintain a stable buffering effect and reduce the shear stress on the adhesive layer. The anti-hydrolysis agent can enhance its chemical corrosion resistance. The waterproof buffer layer is used to prevent the polishing liquid absorbed by the polishing layer from transferring to the back adhesive layer, which is beneficial to reduce the corrosion of the back adhesive layer by the polishing liquid and prevent the back adhesive layer from being corroded and failing, thereby extending the service life of the polishing pad.

[0115] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0116] It should be noted that the embodiments represented by "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments", etc. mentioned in the specification may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing specific features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments that are explicitly or not explicitly described.

[0117] In general, terms should be understood, at least in part, by the context in which they are used. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending, at least in part, on the context. Similarly, terms such as "a," "an," or "the" may also be understood to convey singular usage or to convey plural usage, depending, at least in part, on the context.

[0118] It should be easily understood that “on,” “above,” and “over” in the present disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0120] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A polishing pad, characterized in that: include: Polishing layer; A waterproof buffer layer is provided on one side of the polishing layer in the thickness direction, wherein the waterproof buffer layer is at least composited by thermoplastic polyurethane, polyrotaxane and anti-hydrolysis agent; The back adhesive layer is arranged on the side of the waterproof buffer layer facing away from the polishing layer.

2. The polishing pad according to claim 1, characterized in that The anti-hydrolysis agent includes at least one of polycarbodiimide, epoxy compound and oxazoline; And / or, the waterproof buffer layer also includes thermosetting polyurethane.

3. The polishing pad according to claim 1, characterized in that The back adhesive layer includes at least one of an acrylic-based adhesive and a rubber-based adhesive; And / or, the polishing layer is composited by thermoplastic polyurethane and non-woven fabric.

4. The polishing pad according to claim 1, characterized in that The hardness of the polishing layer is 60A-85A; and / or, the thickness of the polishing layer is 0.5mm-5mm; and / or, the thickness of the waterproof buffer layer is 1mm-7mm.

5. A method for preparing a polishing pad, for preparing the polishing pad according to any one of claims 1 to 4, characterized in that: The following steps are involved: preparing a polishing layer; Casting a buffer layer precasting liquid including thermoplastic polyurethane, an anti-hydrolysis agent, polyrotaxane and a solvent onto one side of the polishing layer in the thickness direction to obtain a waterproof buffer layer; The waterproof buffer layer is subjected to back-adhesive treatment to obtain a back-adhesive layer, thereby obtaining the polishing pad.

6. The method for preparing a polishing pad according to claim 5, characterized in that: The buffer layer precasting liquid comprises, by weight: 100-150 parts of thermoplastic polyurethane, 10-30 parts of polyrotaxane, and 5-10 parts of anti-hydrolysis agent.

7. The method for preparing a polishing pad according to claim 5, characterized in that: The solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

8. The method for preparing a polishing pad according to claim 5, characterized in that: After pouring the buffer layer precasting liquid onto the polishing layer, the method further comprises: The waterproof buffer layer is formed by gelling at a first preset temperature for a first preset time.

9. The method for preparing a polishing pad according to claim 8, characterized in that: The first preset temperature is: 60°C-80°C; and / or the first preset time is: 60min-100min.

10. The method for preparing a polishing pad according to claim 5, characterized in that: The method for preparing the polishing layer comprises: impregnating a polyurethane slurry including a thermoplastic polyurethane resin and a solvent into a nonwoven fabric to obtain an impregnated sample; placing the immersed sample in water for pre-coagulation for a second preset period of time; The pre-condensed impregnated sample is placed in a drying device and dried at a second preset temperature for a third preset time to obtain the polishing layer.

11. The method for preparing a polishing pad according to claim 10, characterized in that: The impregnated sample comprises, by weight: 80-100 parts of thermoplastic polyurethane and 30-60 parts of solvent; and / or, The second preset duration is 20 minutes to 60 minutes; and / or, The second preset temperature is 80°C-120°C; and / or, The third preset duration is 70min-100min.

12. A chemical mechanical polishing device, characterized in that: The polishing pad comprises the polishing pad according to any one of claims 1 to 4.

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