Composite polishing layer, polishing pad and method of making same

Abstract

The present application relates to the polishing technical field, especially to a kind of composite polishing layer, polishing pad and preparation method thereof.The composite polishing layer includes first polishing layer and second polishing layer, and the second polishing layer is coated on the first polishing layer;Wherein, the first polishing layer includes first polyurethane, and the hardness of the first polyurethane is 95-110A, and the number average molecular weight is 3w-5wg / mol;The second polishing layer includes second polyurethane, and the hardness of the second polyurethane is 50-70A, and the number average molecular weight is 5w-20w g / mol.The composite polishing layer can enhance resin to avoid fiber premature occurrence of pull-off simultaneously, enhance uniformity and adjustability, ensure wafer high removal rate, so that polishing pad has longer service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the polishing technical field, and in particular to a composite polishing layer, a polishing pad and a preparation method thereof. BACKGROUND

[0002] In order to obtain a high-quality processing surface of a semiconductor wafer which is super-smooth, non-damaged and free of microscopic defects, a variety of ultra-precision polishing processing methods have been proposed. Chemical mechanical polishing (CMP) is considered to be almost the only hard and brittle photoelectric material surface finishing technology that can provide global planarization so far, which is to form a surface softening layer with lower hardness, weaker strength and smaller binding force on the wafer surface by chemical reaction, and then to remove the material mechanically through the relative movement between the polishing pad, ultra-fine abrasive particles and the wafer. Different from purely chemical or mechanical polishing methods, in CMP, by achieving a balance between chemical action and mechanical action, the problems of slow polishing speed, low surface flatness and more damage which are prone to occur in the former two methods can be avoided.

[0003] The polishing pad is a core component in the CMP process, which plays a role in storing and transporting the polishing liquid and removing the micro-protrusion area on the wafer surface. Its mechanical properties, including hardness, elasticity, compressibility, as well as microstructure and surface roughness, will all affect the polishing effect of the final wafer. A large number of experiments show that, with the increase of polishing time, the polishing pad will undergo obvious physical changes under the action of strong oxidizing polishing liquid. For the polishing layer of the non-woven polishing pad, there are mainly two failure conditions: fiber pull-out or breakage after resin wear, causing the macro "fluffing" phenomenon; and the "glazing" or "smoothing" phenomenon caused by polishing residues and self-wear. The former failure will directly lead to the end of the polishing pad life, and the latter can be restored to a rough and porous surface through surface finishing or adjustment. However, due to the non-uniform properties of the polishing layer such as hardness and density, and the insufficient control of the finishing device and corresponding system parameters, the polishing layer may produce more defects in some parts, resulting in scratches on the wafer surface. Therefore, the polishing layer needs to be improved. SUMMARY

[0004] The present application aims to solve at least one of the technical problems in the related art. To this end, the present application provides a composite polishing layer, a polishing pad and a preparation method thereof. The composite polishing layer can enhance the resin to prevent the fiber from being pulled out too early, while enhancing the uniformity and adjustability, ensuring a high removal rate of the wafer and prolonging the service life of the polishing pad.

[0005] To this end, the first aspect of the present application provides a composite polishing layer, comprising a first polishing layer and a second polishing layer, wherein the second polishing layer is coated on the first polishing layer.

[0006] wherein the first polishing layer comprises a first polyurethane having a hardness of 95-110A and a number average molecular weight of 3w-5w g / mol;

[0007] the second polishing layer comprises a second polyurethane having a hardness of 50-70A and a number average molecular weight of 5w-20w g / mol.

[0008] The inventors found that when the first polyurethane has a hardness of 95-110A and a number average molecular weight of 3w-5w g / mol, it indicates that the content of rigid segments in the polyurethane is relatively high, which can form a high-hardness porous skeleton to provide strong mechanical properties. When the second polyurethane has a hardness of 50-70A and a number average molecular weight of 5w-20w g / mol, it indicates that the proportion of flexible segments in the polyurethane is relatively high, which can form a uniform and adjustable porous polishing layer with high resilience. The combination of the above two polishing layers can form a microstructure of "soft package hard". The first polishing layer can enhance the stability of the fiber under high shear, to a certain extent, solve the problem of delamination, and increase the service life of the polishing layer. The second polishing layer can avoid the high hardness of the polishing pad causing wafer defects. At the same time, using it in the polishing pad can increase the overall resilience, effectively expel the polishing debris, to a certain extent, improve the glazing phenomenon in the polishing process, and maintain the high removal rate of the wafer.

[0009] According to an embodiment of the present application, the first polyurethane is a reaction product comprising a first polyether diol, a first chain extender, a first diisocyanate, and optionally a first end capping agent;

[0010] wherein the first polyether diol has a number average molecular weight of 200-1000 g / mol;

[0011] and / or the content of hard segments in the first polyurethane is 45-75 wt%;

[0012] and / or the first polyether diol comprises at least one of polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolymer diol, propylene oxide-ethylene oxide copolymer diol, bisphenol A polyoxyethylene ether, and bisphenol A polyoxypropylene ether;

[0013] and / or the first chain extender is a small molecule diol or diamine; preferably comprises at least one of diol and diamine; preferably aliphatic diol and / or aromatic diol; more preferably at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, neopentyl glycol, p-phenylenediamine dihydroxyethyl ether, and m-phenylenediamine dihydroxyethyl ether;

[0014] and / or, the first diisocyanate comprises at least one of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, m-xylylene diisocyanate, 1,5-naphthalene diisocyanate;

[0015] and / or, the first end-capping agent comprises a mono-functional end-capping agent and / or a di-functional end-capping agent; preferably a mono-functional end-capping agent containing hydroxyl or amino; more preferably at least one of methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, propyl alcohol.

[0016] According to embodiments of the present application, the second polyurethane is a reaction product of a second polyether diol, a second chain extender, a second diisocyanate, and optionally a second end-capping agent;

[0017] wherein the second polyether diol has a number average molecular weight of 200-3000 g / mol;

[0018] and / or, the second polyurethane has a hard segment content of 5-40 wt%;

[0019] and / or, the second polyether diol comprises at least one of polytetrahydrofuran ether diol, polyether diol with bisphenol A as a starting agent;

[0020] and / or, the polyether diol with bisphenol A as a starting agent comprises, but is not limited to, at least one of bisphenol A polyoxyethylene ether, bisphenol A polyoxypropylene ether;

[0021] and / or, the second chain extender has a molecular weight of 500-2000 g / mol; preferably at least one of polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolydiol, tetrahydrofuran-ethylene oxide copolydiol;

[0022] and / or, the second diisocyanate comprises at least one of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, m-xylylene diisocyanate, 1,5-naphthalene diisocyanate;

[0023] and / or, the second end-capping agent comprises a mono-functional end-capping agent and / or a di-functional end-capping agent; preferably a mono-functional end-capping agent containing hydroxyl or amino; more preferably at least one of methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, propyl alcohol.

[0024] According to embodiments of the present application, the first polishing layer and the second polishing layer are non-foams.

[0025] The second aspect of the present application provides a polishing pad, comprising a composite polishing layer and a non-woven fabric, wherein the composite polishing layer is the composite polishing layer of the first aspect.

[0026] The polishing pad has a high wafer removal rate and a longer service life.

[0027] According to an embodiment of the present application, the first polishing layer is coated on the non-woven fabric.

[0028] And / or, the mass percentage of the composite polishing layer in the polishing pad is 50%-70%, and the mass percentage of the non-woven fabric is 30%-50%.

[0029] The third aspect of the present application provides a preparation method of the polishing pad of the second aspect, comprising:

[0030] Preparation of the composite polishing layer, and compounding the composite polishing layer with the non-woven fabric to obtain the polishing pad.

[0031] According to an embodiment of the present application, the preparation method further comprises:

[0032] Mixing the first polyether diol, the first chain extender and the first diisocyanate to generate a first chain extension reaction to obtain a first impregnating solution;

[0033] Mixing the second polyether diol, the second chain extender and the second diisocyanate to generate a second chain extension reaction to obtain a second impregnating solution;

[0034] Immersing the non-woven fabric in the first impregnating solution and performing a first heat treatment to obtain the non-woven fabric coated with the first polishing layer;

[0035] Immersing the non-woven fabric coated with the first polishing layer in the second impregnating solution and performing a second heat treatment to obtain the polishing pad.

[0036] According to an embodiment of the present application, the preparation method further comprises:

[0037] Mixing the first polyether diol, the third chain extender and the first diisocyanate to obtain a first mixed solution, wherein the molar ratio of isocyanate groups to hydroxyl groups in the first mixed solution is (1:1)-(1.5:1), and a first prepolymerization reaction occurs; adding the fourth chain extender to the mixed solution after the first prepolymerization reaction, so that the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the first prepolymerization reaction is (0.85:1)-(1:1), and a first chain extension reaction occurs to obtain the first impregnating solution;

[0038] The second polyether diol and the second diisocyanate are mixed to obtain a second mixed solution, a molar ratio of isocyanate groups to hydroxyl groups in the second mixed solution is (1:1)-(3:1), and a second prepolymerization reaction occurs; a second chain extender is added to the mixed solution after the second prepolymerization reaction, so that a molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the second prepolymerization reaction is (0.85:1)-(1:1), a second chain extension reaction occurs, and a second impregnation solution is obtained;

[0039] The first chain extender comprises a third chain extender and a fourth chain extender, and the third chain extender and the fourth chain extender are the same or different.

[0040] According to an embodiment of the present application, the solid content of the mixed solution after the first prepolymerization reaction is 30%-50%;

[0041] The solid content of the mixed solution after the first chain extension reaction is 25%-35%; and / or

[0042] The solid content of the mixed solution after the second prepolymerization reaction is 30%-50%; and / or

[0043] The solid content of the mixed solution after the second chain extension reaction is 25%-35%.

[0044] According to an embodiment of the present application, the preparation method further comprises:

[0045] The first impregnation solution is subjected to a dilution treatment to have a solid content of 8%-20%;

[0046] The second impregnation solution is subjected to a dilution treatment to have a solid content of 8%-20%.

[0047] According to an embodiment of the present application, the first prepolymerization reaction is performed for 1-3h;

[0048] The first prepolymerization reaction is performed at a temperature of 50-90℃; and / or

[0049] The first chain extension reaction is performed for 1-3h; and / or

[0050] The first chain extension reaction is performed at a temperature of 50-90℃.

[0051] According to an embodiment of the present application, the second prepolymerization reaction is performed for 1-8h;

[0052] The second prepolymerization reaction is performed at a temperature of 50-90℃; and / or

[0053] The second chain extension reaction is performed for 1-5h; and / or

[0054] The second chain extension reaction is performed at a temperature of 50-90℃.

[0055] According to the embodiment of the present application, the preparation method further comprises: mixing the first mixed solution after the first chain extension reaction and the first end-capping agent to obtain a first impregnation solution;

[0056] and / or, mixing the second mixed solution after the second chain extension reaction and the second end-capping agent to obtain a second impregnation solution.

[0057] Additional aspects and advantages of the present application will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0058] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood by considering the following detailed description, from which the singular aspects become apparent.

[0059] Figure 1 A morphology diagram of the non-woven fabric without treatment in Example 1 of the present application is shown;

[0060] Figure 2 A surface morphology diagram of the first polishing layer in Example 1 of the present application is shown;

[0061] Figure 3 A surface morphology diagram of the second polishing layer in Example 1 of the present application is shown;

[0062] Figure 4 A cross-sectional morphology diagram of the polishing pad in Example 1 of the present application is shown;

[0063] Figure 5 A surface morphology diagram of the composite polishing layer after the polishing pad in Example 1 of the present application is polished for 44h is shown;

[0064] Figure 6 A surface morphology diagram of the polishing layer after the polishing pad in Comparative Example 1 of the present application is polished for 50h is shown;

[0065] Figure 7 A surface morphology diagram of the polishing layer after the polishing pad in Comparative Example 3 of the present application is polished for 14h is shown;

[0066] Figure 8 A profile scanning diagram of the SiC wafer processed by the polishing layer in the present application is shown;

[0067] Figure 9 A profile scanning diagram of the SiC wafer processed for 4h in Comparative Example 1 of the present application is shown. DETAILED DESCRIPTION

[0068] Embodiments of the present application are described in detail below. The embodiments described below are exemplary only and are not to be construed as limiting the present application.

[0069] It should be noted that the terms "first", "second" are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or a quantity of the indicated technical features. Thus, a feature defined with "first", "second" can include one or more of the features. Further, in the description of the present application, the meaning of "a plurality" is two or more unless otherwise specified.

[0070] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The ranges and values should be construed to be approximations that allow for significant variation. Within one aspect, the endpoints are provided as a separate genus. Further, it is to be understood that the description of a single value or description of between two values includes all values therebetween.

[0071] For the purposes of the present application, certain technical and scientific terms are specifically defined below. Unless explicitly stated otherwise, all other technical and scientific terms used herein are intended to have the meanings commonly understood by one of ordinary skill in the art to which the present application pertains.

[0072] In the present document, the terms "comprising" or "including" are intended to be open terms that do not exclude additional aspects, components, or steps.

[0073] In the present document, the terms "optionally", "optional" or "optional" generally mean that the subsequently described event or circumstance can or can not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0074] According to an embodiment of the present application, the first aspect of the present application provides a composite polishing layer, the composite polishing layer comprising a first polishing layer and a second polishing layer, the second polishing layer being coated on the first polishing layer;

[0075] The first polishing layer comprises a first polyurethane, the first polyurethane having a hardness of 95-110A and a number average molecular weight of 3w-5w g / mol.

[0076] The second polishing layer comprises a second polyurethane, the second polyurethane having a hardness of 50-70A and a number average molecular weight of 5w-20w g / mol.

[0077] Thus, a rigid skeleton is constructed by the first polishing layer, the hardness and wear resistance of the polishing layer are improved, and the fiber pull-out is improved. Meanwhile, the flexible second polishing layer is coated on the first polishing layer, the hardness of the rigid skeleton is avoided to be too high to cause wafer scratches, and the resilience is increased to avoid the surface glazing problem caused by the abrasive debris generated in the polishing process to ensure the high removal rate of the wafer in the polishing process. When the polishing pad is applied, the polishing pad also has a longer service life.

[0078] As some specific examples, the hardness of the first polyurethane can be 95A, 96A, 97A, 98A, 99A, 100A, 101A, 102A, 103A, 104A, 105A, 106A, 107A, 108A, 109A, 110A, etc. The number average molecular weight of the first polyurethane can be 3w g / mol, 3.5w g / mol, 4w g / mol, 4.5w g / mol, 5w g / mol, etc.

[0079] As some specific examples, the hardness of the second polyurethane can be 50A, 51A, 52A, 53A, 54A, 55A, 56A, 57A, 58A, 59A, 60A, 61A, 62A, 63A, 64A, 65A, 66A, 67A, 68A, 69A, 70A, etc. The number average molecular weight of the second polyurethane can be 5w g / mol, 6w g / mol, 7w g / mol, 8w g / mol, 9wg / mol, 10w g / mol, 11w g / mol, 12w g / mol, 13w g / mol, 14w g / mol, 15w g / mol, 16w g / mol, 17w g / mol, 18w g / mol, 19w g / mol, 20w g / mol, etc.

[0080] According to a specific embodiment of the present application, the first polyurethane is a reaction product comprising a first polyether diol, a first chain extender, a first diisocyanate, and optionally a first end capping agent; wherein the number average molecular weight of the first polyether diol is 200-1000 g / mol, such as 200 g / mol, 300 g / mol, 400 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 900 g / mol, 1000 g / mol, etc. The polyether diol in the above number average molecular weight range has a higher rigid chain segment content, so that the prepared polyurethane has a higher hardness, which provides strong mechanical properties for the first polishing layer.

[0081] According to a specific embodiment of the present application, the hard segment content in the first polyurethane is 45-75 wt%, as some specific examples, the hard segment content in the first polyurethane is 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, etc. Among them, the "hard segment content" refers to the total mass fraction of small molecule chain extender (molecular weight less than or equal to 250 g / mol) and diisocyanate in the polyurethane.

[0082] According to a specific embodiment of the present application, the first polyether diol includes but is not limited to polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolymer diol, propylene oxide-ethylene oxide copolymer diol, bisphenol A polyoxyethylene ether, bisphenol A polyoxypropylene ether.

[0083] According to a specific embodiment of the present application, the first chain extender is preferably a small molecule chain extender, such as diol, diamine, more preferably aliphatic diol, aromatic diol, including but not limited to ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, p-benzene dihydroxyethyl ether, m-benzene dihydroxyethyl ether.

[0084] According to a specific embodiment of the present application, the first diisocyanate includes but is not limited to 4,4'-diphenyl methane diisocyanate (4,4'-MDI), 2,4-diphenyl methane diisocyanate (2,4-MDI), 2,2'-diphenyl methane diisocyanate (2,2'-MDI), m-xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI).

[0085] According to a specific embodiment of the present application, the raw materials for preparing the first polyurethane can be selected to add or not to add a first end-capping agent, which can be a monofunctional end-capping agent or a bifunctional end-capping agent, preferably a monofunctional end-capping agent containing hydroxyl or amino, including but not limited to methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, propyl alcohol, etc.

[0086] According to a specific embodiment of the present application, the second polyurethane is a reaction product comprising a second polyether diol, a second chain extender, a second diisocyanate, and optionally a second end-capping agent; wherein the number average molecular weight of the second polyether diol is 200-3000 g / mol, such as 200 g / mol, 500 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, etc. The polyether diol in the above number average molecular weight range has a higher flexible chain segment content, so that the prepared polyurethane has lower hardness, forms a uniform and adjustable porous polishing layer, and has high elasticity.

[0087] According to a specific embodiment of the present application, the hard segment content in the second polyurethane is 5-40wt%, as some specific examples, the hard segment content in the second polyurethane is 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt% and the like.

[0088] According to a specific embodiment of the present application, the second polyether diol includes but is not limited to polytetrahydrofuran ether diol, polyether diol with bisphenol A as a starting agent. Wherein the "starting agent" is the starting material in the process of polyol synthesis, used to initiate polymerization. Specifically, the polyether diol with bisphenol A as a starting agent includes but is not limited to bisphenol A polyoxyethylene ether, bisphenol A polyoxypropylene ether.

[0089] According to a specific embodiment of the present application, the molecular weight of the second chain extender is 500-2000g / mol, that is, a flexible chain extender, which can be specifically 500g / mol, 600g / mol, 700g / mol, 800g / mol, 900g / mol, 1000g / mol, 1100g / mol, 1200g / mol, 1300g / mol, 1400g / mol, 1500g / mol, 1600g / mol, 1700g / mol, 1800g / mol, 1900g / mol, 2000g / mol and the like. Specifically including but not limited to polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolymer diol, tetrahydrofuran-ethylene oxide copolymer diol;

[0090] According to a specific embodiment of the present application, the second diisocyanate includes but is not limited to 4,4'-diphenyl methane diisocyanate, 2,4-diphenyl methane diisocyanate, 2,2'-diphenyl methane diisocyanate, m-xylylene diisocyanate, 1,5-naphthalene diisocyanate.

[0091] According to a specific embodiment of the present application, the raw materials for preparing the second polyurethane can be selected to add or not to add a second end-capping agent, which includes a monofunctional end-capping agent and / or a difunctional end-capping agent; preferably a monofunctional end-capping agent containing hydroxyl or amino; including but not limited to methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, propyl alcohol.

[0092] According to a specific embodiment of the present application, the first polishing layer and the second polishing layer are non-foaming bodies. Thus, a more stable and uniform polishing effect can be provided during polishing.

[0093] The second aspect of the present application provides a polishing pad, which comprises a composite polishing layer and a non-woven fabric, wherein the composite polishing layer is the composite polishing layer of the first aspect.

[0094] According to a specific embodiment of the present application, the first polishing layer is coated on the non-woven fabric.

[0095] According to a specific embodiment of the present application, the type of the non-woven fabric is not particularly limited, including but not limited to needle-punched non-woven fabric or spunlace non-woven fabric, such as polypropylene, polyester, polyamide or mixture thereof. The selected materials include but are not limited to polypropylene, polyester, polyamide, viscose, acrylic, polyethylene, chlorofiber, polyester, polyamide.

[0096] According to a specific embodiment of the present application, the mass ratio of the composite polishing layer is not particularly limited, and as some specific examples, it is preferably 50-70%, such as 50%, 60%, 70% and the like. The mass ratio of the corresponding non-woven fabric is 30%-50%, such as 30%, 40%, 50% and the like.

[0097] The third aspect of the present application provides a preparation method of the polishing pad of the second aspect, comprising:

[0098] Preparation of the composite polishing layer, and compounding the composite polishing layer with the non-woven fabric to obtain the polishing pad.

[0099] According to a specific embodiment of the present application, the preparation method further comprises:

[0100] (1) mixing the first polyether diol, the first chain extender and the first diisocyanate to occur the first chain extension reaction to obtain the first impregnation solution.

[0101] Specifically, this step can further comprise: mixing the first polyether diol, the third chain extender and the first diisocyanate to obtain a first mixed solution, the molar ratio of isocyanate groups to hydroxyl groups in the first mixed solution is (1:1)-(1.5:1), and the first prepolymerization reaction occurs; adding the fourth chain extender to the mixed solution after the first prepolymerization reaction, so that the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the first prepolymerization reaction is (0.85:1)-(1:1), and the first chain extension reaction occurs to obtain the first impregnation solution.

[0102] Specifically, the first chain extender comprises a third chain extender and a fourth chain extender, and the third chain extender and the fourth chain extender are the same or different. That is, the third chain extender and the fourth chain extender independently comprise at least one of diols and diamines; preferably aliphatic diols and / or aromatic diols; more preferably at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, neopentyl glycol, p-phenylenediamine dihydroxyethyl ether and m-phenylenediamine dihydroxyethyl ether.

[0103] Specifically, the molar ratio of isocyanate groups to hydroxyl groups in the first mixed solution is (1:1)-(1.5:1), such as 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc. The time of the first prepolymerization reaction is not particularly limited, and can be selected by those skilled in the art according to actual needs. As some specific examples, the time of the first prepolymerization reaction can be 1-3h, such as 1h, 2h, 3h, etc. The temperature of the first prepolymerization reaction is also not particularly limited, and is preferably 50-90℃, such as 50℃, 60℃, 70℃, 80℃, 90℃, etc.

[0104] Specifically, the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the first prepolymerization reaction is (0.85:1)-(1:1), such as 0.85:1, 0.9:1, 0.95:1, 1:1, etc. The time of the first chain extension reaction is not particularly limited, and can be selected by those skilled in the art according to actual needs. As some specific examples, the time of the first chain extension reaction can be 1-3h, such as 1h, 2h, 3h, etc. The temperature of the first chain extension reaction is also not particularly limited, and is preferably 50-90℃, such as 50℃, 60℃, 70℃, 80℃, 90℃, etc.

[0105] Specifically, the solid content of the mixed solution after the first prepolymerization reaction is 30%-50%, and as some specific examples, the solid content of the mixed solution after the first prepolymerization reaction can be 30%, 35%, 40%, 45%, 50%, etc. The solid content of the mixed solution after the first chain extension reaction is 25%-35%, and as some specific examples, the solid content of the mixed solution after the first chain extension reaction is 25%, 30%, 35%, etc.

[0106] Specifically, the preparation method can further comprise: dissolving the first polyether diol and the third chain extender in the first solvent, and adding the first diisocyanate. The type of the first solvent is not particularly limited, and as some specific examples, at least one of N,N'-dimethylformamide (DMF) or N,N'-dimethylacetamide (DMAC) or N-methylpyrrolidone (NMP) can be selected.

[0107] Specifically, the preparation method can further comprise: mixing the mixed solution subjected to the first chain extension reaction and the first end-capping agent to obtain a first impregnation solution. The type of the first end-capping agent is as described above.

[0108] (2) mixing the second polyether diol, the second chain extender, and the second diisocyanate to undergo a second chain extension reaction to obtain a second impregnation solution.

[0109] Specifically, the step can further include: mixing the second polyether diol and the second diisocyanate to obtain a second mixed solution, the molar ratio of isocyanate groups to hydroxyl groups in the second mixed solution being (1:1)-(3:1), and a second prepolymerization reaction occurring; adding a second chain extender to the mixed solution after the second prepolymerization reaction, so that the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the second prepolymerization reaction is (0.85:1)-(1:1), a second chain extension reaction occurs, and a second impregnating solution is obtained.

[0110] Specifically, the molar ratio of isocyanate groups to hydroxyl groups in the second mixed solution is (1:1)-(3:1), for example, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc. The time of the second prepolymerization reaction is not particularly limited, and can be selected by a person skilled in the art according to actual needs. As some specific examples, the time of the second prepolymerization reaction can be 1-8h, for example, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, etc. The temperature of the second prepolymerization reaction is also not particularly limited, and is preferably 50-90℃, for example, 50℃, 60℃, 70℃, 80℃, 90℃, etc.

[0111] Specifically, the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the second prepolymerization reaction is (0.85:1)-(1:1), for example, 0.85:1, 0.9:1, 0.95:1, 1:1, etc. The time of the second chain extension reaction is not particularly limited, and can be selected by a person skilled in the art according to actual needs. As some specific examples, the time of the second chain extension reaction can be 1-5h, for example, 1h, 2h, 3h, 4h, 5h, etc. The temperature of the second chain extension reaction is also not particularly limited, and is preferably 50-90℃, for example, 50℃, 60℃, 70℃, 80℃, 90℃, etc.

[0112] Specifically, the solid content of the mixed solution after the second prepolymerization reaction is 30%-50%, and as some specific examples, the solid content of the mixed solution after the second prepolymerization reaction can be 30%, 35%, 40%, 45%, 50%, etc. The solid content of the mixed solution after the second chain extension reaction is 25%-35%, and as some specific examples, the solid content of the mixed solution after the second chain extension reaction is 25%, 30%, 35%, etc.

[0113] Specifically, the preparation method can further include: dissolving the second polyether diol in a second solvent and adding the second diisocyanate. The type of the second solvent is not particularly limited, and as some specific examples, at least one of N,N'-dimethylformamide (DMF) or N,N'-dimethylacetamide (DMAC) or N-methylpyrrolidone (NMP) can be selected.

[0114] Specifically, the preparation method can further include mixing the mixture solution in which the second chain extension reaction occurs and a second end-capping agent to obtain a second dipping solution. The type of the second end-capping agent is as described above.

[0115] (3) immersing the non-woven fabric in the first dipping solution, performing a first heat treatment, and obtaining the non-woven fabric coated with a first polishing layer.

[0116] Specifically, the preparation method can further include diluting the first dipping solution and then immersing the non-woven fabric in the first dipping solution. The first dipping solution can be diluted to 8%-20%, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc. Thus, better wettability is achieved.

[0117] Specifically, the non-woven fabric is immersed in the first dipping solution, and after complete immersion, the excess dipping solution on the upper and lower surfaces is scraped off, and then heat treatment is performed. Meanwhile, the immersion process can be performed under pressurized conditions, and the pressurized conditions can be achieved by vacuum extraction, the vacuum extraction time can be 0-10s, and the vacuum degree is 0-0.9MPa.

[0118] Specifically, the temperature and time of the first heat treatment are not particularly limited, and drying of the solvent is achieved, for example, 150-180℃ for 0.1-1h, etc.

[0119] (4) immersing the non-woven fabric coated with the first polishing layer in the second dipping solution, performing a second heat treatment, and obtaining the polishing pad.

[0120] Specifically, the preparation method can further include diluting the second dipping solution and then immersing the non-woven fabric coated with the first polishing layer in the second dipping solution. The second dipping solution can be diluted to 8%-20%, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc. Thus, better wettability is achieved.

[0121] Specifically, the non-woven fabric coated with the first polishing layer is immersed in the second dipping solution, and after complete immersion, the excess dipping solution on the upper and lower surfaces is scraped off, and then heat treatment is performed. Meanwhile, the immersion process can be performed under pressurized conditions, and the pressurized conditions can be achieved by vacuum extraction, the vacuum extraction time can be 0-10s, and the vacuum degree is 0-0.9MPa.

[0122] Specifically, the temperature and time of the second heat treatment are not particularly limited, and drying of the solvent is achieved, for example, 150-180℃ for 0.1-1h, etc. In addition, after the second heat treatment is completed, conventional grinding, grooving, cutting, and back gluing operations, etc. can be performed to obtain the polishing pad.

[0123] The solutions of the application will be explained below with reference to examples. Those skilled in the art will understand that the examples below are only intended to illustrate the application and should not be considered as limiting the scope of the application. If a specific technique or condition is not mentioned in the examples, it is performed according to the technique or condition described in the literature in the art or according to the product manual. If the manufacturer of the reagent or instrument is not mentioned, it is a conventional product that can be obtained commercially.

[0124] Example 1

[0125] The components and weight percentages of the polishing pad prepared in this example are as follows: polyurethane 60% and non-woven fabric 40%, the non-woven fabric is needle-punched polyester non-woven fabric with a grammage of 270 g / m 2 , a fiber diameter of 17 μm, and a thickness of 1.6 mm.

[0126] Preparation of the first impregnation solution: polytetramethylene glycol (PTMG1000) with a molecular weight of 1000 g / mol and 1,4-butanediol were dissolved in DMF solvent at a molar ratio of 10:1; a diisocyanate, which is a mixture of 2,4-MDI and 4,4'-MDI, was added dropwise at a molar ratio of isocyanate groups to alcohol hydroxyl groups of 1.5:1, the solid content of the solution was 40%, after 1 h of reaction, p-hydroquinone dihydroxyethyl ether and DMAC were added to make the molar ratio of alcohol hydroxyl groups to isocyanate groups 1:0.95, the solid content of the solution was 30%, after 1.5 h of reaction, methanol was added for end-capping for 1.5 h, and the reaction temperature was 70°C throughout the process;

[0127] Preparation of the second impregnation solution: polytetramethylene glycol (PTMG2000) with a molecular weight of 2000 g / mol was dissolved in DMAC solvent, a diisocyanate, which is 4,4'-MDI, was added dropwise at a molar ratio of alcohol hydroxyl groups to isocyanate groups of 1:1.5, the solid content of the solution was 40%, after 2 h of reaction at 65°C, polyethylene glycol (PEG 600) was added to make the molar ratio of alcohol hydroxyl groups to isocyanate groups 1:0.9, the temperature was raised to 80°C, the solid content of the solution was 30%, and the reaction was carried out for 3 h;

[0128] The first impregnation solution was diluted to 8% with DMF solvent, the non-woven fabric was laid on a flat glass plate, the first impregnation solution was poured onto the surface, after complete soaking, the excess impregnation solution on the upper and lower surfaces was scraped off, and it was sent into a 100°C oven for drying for 60 min, then a flat glass plate was pressed on the upper surface, the temperature was raised to 180°C for further treatment for 10 min, and the first polishing layer was obtained;

[0129] The second impregnating solution is diluted to 15% with NMP solvent, and is poured on the surface of the first polishing layer, squeezed with a roller until the impregnating solution is fully saturated, and the excess impregnating solution on the upper and lower surfaces is scraped off, and is sent into a drying oven at 120°C for 80 min, and then is subjected to normal polishing, grooving, cutting, and backing operations to obtain the polishing pad.

[0130] Example 2

[0131] The components and weight percentages of the polishing pad prepared in this example are as follows: polyurethane 50% and non-woven fabric 50%, the non-woven fabric being a spunlace polyester non-woven fabric with a grammage of 300 g / m 2 , a fiber diameter of 16 μm, and a thickness of 1.9 mm.

[0132] Preparation of the first impregnating solution: polyethylene glycol (PEG200) with a molecular weight of 200 g / mol and hexanediol are put into DMAC solvent, the molar ratio being 20:1; a binary isocyanate, which is a mixture of 2,4-MDI and 4,4'-MDI, is added dropwise, the molar ratio of isocyanate groups to alcohol hydroxyl groups being 1.06:1, the solution solid content being 35%, after 3 h of reaction, resorcinol dihydroxyethyl ether and DMF are added, the molar ratio of alcohol hydroxyl groups to isocyanate groups being 0.99:1, the solution solid content being 30%, and the reaction temperature being 60°C throughout the reaction process for 2 h;

[0133] Preparation of the second impregnating solution: PTMG with a molecular weight of 1400 g / mol is put into DMF solvent, a binary isocyanate, which is 4,4'-MDI, is added dropwise, the molar ratio of alcohol hydroxyl groups to isocyanate groups being 1:2, the solution solid content being 30%, after 1 h of reaction at 80°C, tetrahydrofuran- propylene oxide copolydiol and DMF are added, the molar ratio of alcohol hydroxyl groups to isocyanate groups being 1:0.97, the solution solid content being 30%, and the temperature being raised to 85°C for 3 h of reaction;

[0134] The first impregnating solution is diluted to 10% with DMF solvent, the non-woven fabric is laid on a flat marble material adsorption platform, the first impregnating solution is poured on the surface, the vacuum is turned on, after there is no liquid residue on the upper layer, the excess impregnating solution on the lower surface is scraped off, and is sent into a drying oven at 105°C for 70 min, then a flat glass plate is pressed on the upper surface, the temperature is raised to 150°C for further processing for 60 min, and the first polishing layer is obtained;

[0135] The second impregnating solution is diluted to 8% with NMP solvent, and is poured on the surface of the first polishing layer, squeezed with a roller until the impregnating solution is fully saturated, and the excess impregnating solution on the upper and lower surfaces is scraped off, and is sent into a drying oven at 120°C for 80 min, and then is subjected to normal polishing, grooving, cutting, and backing operations to obtain the polishing pad.

[0136] Example 3

[0137] The polishing pad prepared in this example has the following components and weight percentages: polyurethane 70% and non-woven fabric 30%, the non-woven fabric being needle-punched polyester non-woven fabric with a grammage of 220 g / m 2 , a fiber diameter of 20 μm, and a thickness of 1.7 mm.

[0138] Preparation of the first impregnating solution: polytetramethylene glycol ether (PTMG 250) with a molecular weight of 250 g / mol and resorcinol dihydroxy ether were put into DMAC solvent, the molar ratio being 12:1; a binary isocyanate, which was a mixture of 2,4-MDI and 4,4'-MDI, was added dropwise, the molar ratio of isocyanate groups to alcohol hydroxyl groups being 1.3:1, the solution solid content being 37%, after 2 h of reaction, ethylene glycol and NMP were added to make the molar ratio of alcohol hydroxyl groups to isocyanate groups 1:0.95, the solution solid content being 30%, the reaction temperature being 55°C throughout the reaction, and the reaction time being 1.5 h;

[0139] Preparation of the second impregnating solution: the reaction temperature was 90°C throughout, PTMG with a molecular weight of 1200 g / mol was put into DMF solvent, a binary isocyanate, which was a mixture of 2,4-MDI and 4,4'-MDI, was added dropwise, the molar ratio of alcohol hydroxyl groups to isocyanate groups being 1:1.2, the solution solid content being 45%, after 2 h of reaction, polyethylene glycol (PEG 1000) and NMP were added, the molar ratio of alcohol hydroxyl groups to isocyanate groups being 1:0.99, the solution solid content being 30%, after 2 h of reaction, methanol was added and the temperature was lowered to 60°C and the reaction was continued for another 0.5 h;

[0140] The first impregnating solution was diluted to 18% with DMAC solvent, the non-woven fabric was laid on a flat glass plate, the first impregnating solution was poured onto the surface, after complete soaking, the excess impregnating solution on the upper and lower surfaces was scraped off, and it was sent into a 100°C oven to dry for 60 min, then a flat glass plate was pressed onto the upper surface, the temperature was raised to 170°C and it was treated for another 30 min, to obtain the first polishing layer;

[0141] The second impregnating solution was diluted to 11% with NMP solvent, and it was poured onto the surface of the first polishing layer, and it was extruded with a roller until the impregnating solution was completely soaked, then the excess impregnating solution on the upper and lower surfaces was scraped off, and it was sent into a 120°C oven to dry for 80 min, and then it was subjected to normal polishing, grooving, cutting, and backing operations, to obtain the polishing pad.

[0142] Example 4

[0143] The polishing pad prepared in this example has the following components and weight percentages: polyurethane 70% and non-woven fabric 30%, the non-woven fabric being needle-punched polyester non-woven fabric with a grammage of 220 g / m 2 , a fiber diameter of 20 μm / 14 μm, and a thickness of 1.7 mm.

[0144] Preparation of the first impregnating solution: diphenyl A polyoxyethylene ether, neopentyl glycol were put into DMF solvent, the molar ratio was 25:1; binary isocyanate was added dropwise, which was 4,4'-MDI, the molar ratio of isocyanate group and alcohol hydroxyl was 1.05:1, the solid content of the solution was 35%, after 2h reaction, 1,4-butanediol and DMF were added, so that the molar ratio of alcohol hydroxyl and isocyanate group was 1:1, the solid content of the solution was 30%, after 1.5h reaction, isobutyl alcohol was added and reacted for another 1h, the reaction temperature was 70℃ throughout the process;

[0145] Preparation of the second impregnating solution: PTMG with a molecular weight of 1200g / mol was put into DMF solvent, binary isocyanate was added dropwise, which was a mixture of 2,4-MDI and 4,4'-MDI, the molar ratio of alcohol hydroxyl and isocyanate was 1:1.2, the solid content of the solution was 45%, after 2h reaction at 85℃, polypropylene glycol (PPG 600) and NMP were added, the molar ratio of alcohol hydroxyl and isocyanate group was 0.99:1, the solid content of the solution was 30%, after the temperature was raised to 90℃ and reacted for another 2h, ethanol was added and the temperature was lowered to 65℃ and continued to react for another 0.5h;

[0146] The first impregnating solution was diluted to 9% with DMAC solvent, the non-woven fabric was laid on an aluminum vacuum adsorption platform, the first impregnating solution was poured on the surface, the vacuum was turned on, the impregnating solution completely penetrated the non-woven fabric, the excess impregnating solution on the upper and lower surfaces was scraped off, and it was sent into a 100℃ oven for drying for 60min, then a flat glass plate was pressed on the upper surface, the temperature was raised to 160℃ and processed for another 20min, to obtain the first polishing layer;

[0147] The second impregnating solution was diluted to 12% with NMP solvent, and it was poured on the surface of the first polishing layer, and the impregnating solution completely penetrated after being extruded with a roller, the excess impregnating solution on the upper and lower surfaces was scraped off, and it was sent into a 120℃ oven for drying for 80min, and then the conventional polishing, grooving, cutting and backing operations were carried out, to obtain the polishing pad.

[0148] Comparative Example 1

[0149] The composition and weight percentage of the polishing pad prepared in this comparative example were as follows: polyurethane 60% and non-woven fabric 40%.

[0150] Preparation of the impregnating solution: polytetrahydrofuran glycol ether (PTMG 650), ethylene glycol were put into DMF solvent, the molar ratio was 13:1; binary isocyanate was added dropwise, which was NDI, the molar ratio of isocyanate group and alcohol hydroxyl was 1.15:1, the solid content of the solution was 32%, after 2h reaction, ethylene glycol and DMF were added, so that the molar ratio of alcohol hydroxyl and isocyanate group was 1:0.96, the solid content of the solution was 28%, and the reaction was continued for another 2h;

[0151] The impregnation solution was diluted to 20% with DMAC solvent, the non-woven fabric was laid on a flat glass plate, the impregnation solution was poured on the surface, after complete soaking, the excess impregnation solution on the upper and lower surfaces was scraped off, and it was sent into a 100°C oven for drying for 90 min, then a flat glass plate was pressed on the upper surface, the temperature was raised to 150°C for further treatment for 10 min, and then the conventional polishing, grooving, cutting, and backing operations were performed to obtain the polishing pad.

[0152] Comparative Example 2

[0153] The components and weight percentages of the polishing pad prepared in this comparative example are as follows: polyurethane 60% and non-woven fabric 40%.

[0154] Preparation of the impregnation solution: PTMG with a molecular weight of 1800 g / mol was put into DMF solvent, and diisocyanate, which is a mixture of 2,4-MDI and 4,4'-MDI and NDI, was added dropwise, the molar ratio of alcohol hydroxyl and isocyanate was 1:1.1, the solution solid content was 40%, after 2h of reaction, polyethylene glycol (PEG 2000) and NMP were added, the molar ratio of alcohol hydroxyl and isocyanate group was 0.98:1, the solution solid content was 25%, and the reaction was carried out for 3h.

[0155] The impregnation solution was diluted to 19% with DMF solvent, the non-woven fabric was laid on a flat glass plate, the impregnation solution was poured on the surface, after complete soaking, the excess impregnation solution on the upper and lower surfaces was scraped off, and it was sent into a 100°C oven for drying for 90 min, then a flat glass plate was pressed on the upper surface, the temperature was raised to 175°C for further treatment for 10 min, and then the conventional polishing, grooving, cutting, and backing operations were performed to obtain the polishing pad.

[0156] Comparative Example 3

[0157] The components and weight percentages of the polishing pad prepared in this comparative example are as follows: polyurethane 60% and non-woven fabric 40%.

[0158] Preparation of the first impregnation solution: TPU-50A (a conventional commercial material with hardness ≥ 50A) was put into DMF solvent in batches, and stirred at 60°C until completely dissolved, the solution solid content was 11%;

[0159] Preparation of the second impregnation solution: TPU-95A (a conventional commercial material with hardness ≥ 95A) was put into NMP solvent in batches, and stirred at 60°C until completely dissolved, the solution solid content was 11%;

[0160] The non-woven fabric was laid on a flat glass plate, the first impregnation solution was poured on the surface, after complete soaking, the excess impregnation solution on the upper and lower surfaces was scraped off, and it was sent into a 120°C oven for drying for 60 min, then a flat glass plate was pressed on the upper surface, the temperature was raised to 160°C for further treatment for 20 min, to obtain the first polishing layer;

[0161] The first polishing layer is placed on an aluminum alloy material adsorption platform, the second immersion liquid is poured on the surface, the vacuum is turned on until the lower liquid is completely immersed, the excess immersion liquid on the lower surface is scraped off, and the polishing pad is sent into a 120°C oven for drying for 70 minutes, and then the conventional polishing, grooving, cutting, and back adhesive operations are performed to obtain the polishing pad.

[0162] Test example

[0163] (1) Wafer polishing test

[0164] After the polishing pad is polished, grooved, and glued, it is attached to a chemical mechanical polishing machine to continuously polish the carbon face or silicon face of a 6-inch silicon carbide wafer for 2 hours, and the thickness removal amount per unit time of each surface of the wafer is tested, that is, the removal rate;

[0165] The polishing pad surface is obviously hairy or the SiC wafer surface has multiple penetrating scratches, which is considered to be invalid, and the polishing time from the beginning of polishing to the occurrence of obvious hairiness is considered to be the polishing layer life;

[0166] (2) Wafer surface test

[0167] A three-dimensional white light profilometer is used to test each surface of the wafer before and after polishing;

[0168] (3) Polishing layer hardness test

[0169] Referring to GB / T2411-2008 "Determination of indentation hardness (Shore hardness) of plastics and ebonite using a scleroscope", several layers of samples are stacked to make the test thickness greater than 4mm, and the hardness of five points of the sample is tested by a Shore A hardness tester to obtain the average value;

[0170] (4) Polyurethane hard segment content test

[0171] The polyurethane hard segment content is tested by nuclear magnetic resonance or Fourier infrared transform spectroscopy;

[0172] (5) Polishing layer compression rate test

[0173] Referring to GB / T 24442.1-2009 "Determination of compression properties of textiles Part 1: Constant method", the polishing layer is first polished, a constant pressure of 8N is set, the temperature is raised from room temperature to 75°C, the pressure is removed and the temperature is restored to room temperature, and then the initial, test period, and test end thicknesses are measured to obtain the compression rate and resilience rate;

[0174] (6) Micro-morphology test

[0175] The surface and cross-section micro-morphology of the polishing layer is tested by field emission scanning electron microscopy.

[0176] Among themFigures 1-7 The surface and cross-section micro-morphology of the polishing layer are shown in the following figures. Figure 1 It can be seen that, Figure 2 The surface is obviously covered with resin.

[0177] Figures 8-9 The test results of each surface of the wafer before and after polishing are shown in the following table. Among them Figure 8 The wafer shows a water ripple surface with a height difference of 882 nm, indicating that only chemical action is used and the mechanical removal effect is poor. Figure 9 It shows that the polished wafer surface in Comparative Example 1 has through scratches.

[0178] The remaining test results are shown in the following table. The results show that, compared with the comparative examples, the polishing layer prepared by the method provided in the present application has a high wafer removal rate, and the polishing pad has a longer service life.

[0179] Table 1

[0180]

[0181] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0182] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A composite polishing layer, characterized by, The composite polishing layer comprises a first polishing layer and a second polishing layer, and the second polishing layer is coated on the first polishing layer. The first polishing layer comprises a first polyurethane, the hardness of the first polyurethane is 95-110 A, and the number average molecular weight of the first polyurethane is 3w-5w g / mol. The second polishing layer comprises a second polyurethane, the hardness of the second polyurethane is 50-70 A, and the number average molecular weight of the second polyurethane is 5w-20w g / mol. The first polyurethane is a reaction product comprising a first polyether diol, a first chain extender, and a first diisocyanate. The first polyether diol comprises at least one of polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolymer diol, propylene oxide-ethylene oxide copolymer diol, bisphenol A polyoxyethylene ether, and bisphenol A polyoxypropylene ether. The first diisocyanate comprises at least one of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, m-xylylene diisocyanate, and 1,5-naphthalene diisocyanate. The second polyurethane is a reaction product comprising a second polyether diol, a second chain extender, and a second diisocyanate. The second polyether diol comprises at least one of polytetrahydrofuran ether diol and polyether diol with bisphenol A as a starting agent. The second diisocyanate comprises at least one of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, m-xylylene diisocyanate, and 1,5-naphthalene diisocyanate.

2. The composite polishing layer of claim 1, wherein The first polyurethane is a reaction product comprising a first polyether diol, a first chain extender, a first diisocyanate, and a first end capping agent.

3. The composite polishing layer of claim 2, wherein, The number average molecular weight of the first polyether diol is 200-1000 g / mol. And / or, the hard segment content in the first polyurethane is 45-75 wt%. And / or, the first chain extender comprises at least one of a diol and a diamine. And / or, the first end capping agent comprises a monofunctional end capping agent and / or a bifunctional end capping agent.

4. The composite polishing layer of claim 3, wherein The first chain extender comprises an aliphatic diol and / or an aromatic diol. And / or, the first end capping agent comprises a monofunctional end capping agent containing a hydroxyl group or an amino group.

5. The composite polishing layer of claim 4, wherein, The first chain extender comprises at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, p-benzene diol dihydroxyethyl ether, and m-benzene diol dihydroxyethyl ether. And / or, the first end capping agent comprises at least one of methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, and propyl alcohol.

6. The composite polishing layer of claim 1, wherein The second polyurethane is a reaction product comprising a second polyether diol, a second chain extender, a second diisocyanate, and a second end capping agent.

7. The composite polishing layer of claim 6, wherein The number average molecular weight of the second polyether diol is 200-3000 g / mol. And / or, the hard segment content in the second polyurethane is 5-40 wt%. And / or, the polyether diol with bisphenol A as a starting agent comprises at least one of bisphenol A polyoxyethylene ether and bisphenol A polyoxypropylene ether; And / or, the second chain extender has a molecular weight of 500-2000 g / mol; And / or, the second chain extender comprises at least one of polyethylene glycol, polypropylene glycol, tetrahydrofuran-propylene oxide copolymer diol, and tetrahydrofuran-ethylene oxide copolymer diol; And / or, the second end-capping agent comprises a monofunctional end-capping agent and / or a bifunctional end-capping agent.

8. The composite polishing layer of claim 7, wherein, The second end-capping agent comprises a monofunctional end-capping agent containing a hydroxyl group or an amino group.

9. The composite polishing layer of claim 8, wherein, The second end-capping agent comprises at least one of methanol, phenol, p-chlorophenol, ethanol, dibutylamine, 2-isopropylamine, isobutyl alcohol, n-butyl alcohol, amyl alcohol, isoamyl alcohol, and propyl alcohol.

10. The composite polishing layer of claim 1, wherein, The first polishing layer and the second polishing layer are non-foamed bodies.

11. A polishing pad, characterized by, The polishing pad comprises a composite polishing layer and a non-woven fabric, and the composite polishing layer is the composite polishing layer according to any one of claims 1-10.

12. The polishing pad of claim 11, wherein, The first polishing layer is coated on the non-woven fabric. And / or, the mass ratio of the composite polishing layer in the polishing pad is 50%-70%, and the mass ratio of the non-woven fabric is 30%-50%.

13. A method of making the polishing pad of claim 11 or 12, wherein, The preparation method comprises: Preparation of the composite polishing layer, and compounding the composite polishing layer with the non-woven fabric to obtain the polishing pad.

14. The method of claim 13, wherein, The preparation method further comprises: Mixing the first polyether diol, the first chain extender, and the first diisocyanate to generate a first chain extension reaction to obtain a first impregnating solution; Mixing the second polyether diol, the second chain extender, and the second diisocyanate to generate a second chain extension reaction to obtain a second impregnating solution; Immersing the non-woven fabric in the first impregnating solution, performing a first heat treatment, and obtaining a non-woven fabric coated with a first polishing layer to obtain the first polishing layer; Immersing the non-woven fabric coated with the first polishing layer in the second impregnating solution, performing a second heat treatment, and obtaining the polishing pad.

15. The preparation method according to claim 13, characterized in that, The preparation method further comprises: Mixing the first polyether diol, the third chain extender, and the first diisocyanate to obtain a first mixed solution, the molar ratio of isocyanate groups to hydroxyl groups in the first mixed solution being (1:1)-(1.5:1), generating a first prepolymerization reaction; adding the fourth chain extender to the mixed solution after the first prepolymerization reaction, so that the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the first prepolymerization reaction is (0.85:1)-(1:1), generating a first chain extension reaction to obtain a first impregnating solution; Mixing the second polyether diol and the second diisocyanate to obtain a second mixed solution, the molar ratio of isocyanate groups to hydroxyl groups in the second mixed solution being (1:1)-(3:1), generating a second prepolymerization reaction; adding the second chain extender to the mixed solution after the second prepolymerization reaction, so that the molar ratio of isocyanate groups to hydroxyl groups in the mixed solution after the second prepolymerization reaction is (0.85:1)-(1:1), generating a second chain extension reaction to obtain a second impregnating solution; The first chain extender comprises a third chain extender and a fourth chain extender, and the third chain extender and the fourth chain extender are the same or different.

16. The method of claim 15, wherein, The solid content of the mixed solution after the first prepolymerization reaction is 30%-50%. And / or, the solid content of the mixed solution after the first chain extension reaction is 25%-35%; And / or, the solid content of the mixed solution after the second prepolymerization reaction is 30%-50%; And / or, the solid content of the mixed solution after the second chain extension reaction is 25%-35%.

17. The method of making according to any one of claims 15-16, wherein, The preparation method further comprises: diluting the first impregnation solution to a solid content of 8%-20%; And / or, diluting the second impregnation solution to a solid content of 8%-20%.

18. The method of any one of claims 15-17, wherein, The first prepolymerization reaction time is 1-3h; And / or, the first prepolymerization reaction temperature is 50-90℃; And / or, the first chain extension reaction time is 1-3h; And / or, the first chain extension reaction temperature is 50-90℃.

19. The method of any one of claims 15-17, wherein, The second prepolymerization reaction time is 1-8h; And / or, the second prepolymerization reaction temperature is 50-90℃; And / or, the second chain extension reaction time is 1-5h; And / or, the second chain extension reaction temperature is 50-90℃.

20. The method of any one of claims 14-19, wherein, The preparation method further comprises: mixing the mixed solution after the first chain extension reaction and the first end-capping agent to obtain the first impregnation solution; And / or, mixing the mixed solution after the second chain extension reaction and the second end-capping agent to obtain the second impregnation solution.

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