A composite polishing pad and its preparation method and application

Abstract

The present invention provides a composite polishing pad, a preparation method thereof and an application thereof, relating to the technical field of polishing material processes. The composite polishing pad of the present invention comprises components: non-woven fabric, polyester, glycerol monostearate and filler; the non-woven fabric is a fiber non-woven fabric treated with a mixed solution of polyacrylamide and glycerol, and the mass ratio of polyacrylamide to glycerol is 20-40:1; the polyester is selected from polyurethane with a molecular weight of 5000-20000; the preparation method comprises the steps of: (1) fiber pretreatment: mixing the fibers with a dispersion liquid, beating and dispersing, and ultrasonic treatment; (2) mixing the polyurethane and the glycerol monostearate solution to obtain a polymer solution; mixing the polymer solution with the filler to obtain an infiltration liquid; (3) pressurized infiltration and surface polishing to obtain the composite polishing pad. The composite polishing pad prepared by the present invention has both high polishing rate and high wear resistance, and is widely used in wafer polishing treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of polishing material processes, and particularly relates to a composite polishing pad, a preparation method thereof, and an application thereof. Background Art

[0002] Chemical mechanical planarization (CMP), also known as chemical mechanical polishing, is a method for planarizing a silicon wafer or other substrate material during a processing using chemical corrosion and mechanical force. Its principle is as follows: The wafer rotates relative to the polishing pad under a certain pressure and in the presence of a polishing liquid, and the removal of the surface material of the wafer is achieved by using the abrasive grinding and chemical component corrosion effects. The polishing liquid, the wafer, and the polishing pad are the three most important elements in CMP. Controlling the chemical reaction between the polishing liquid and the wafer, and controlling the mechanical grinding effect when the polishing liquid, the polishing pad, and the wafer are in contact with each other can achieve efficient grinding of the wafer and obtain a smooth surface.

[0003] Polishing pads can be classified into polyurethane polishing pads, non-woven fabric polishing pads, and composite polishing pads according to different materials. The polishing pad plays the following roles in grinding: It can effectively and evenly transport the polishing liquid to different areas of the polishing pad; smoothly discharge the reactants, debris, etc. after polishing to achieve an effective removal effect; keep the polishing process stable and the surface unchanged to obtain a better surface topography of the wafer. Therefore, the hardness, roughness, density, etc. of the polishing pad have a decisive influence on the performance of the polishing pad.

[0004] Chinese Patent CN110977756A discloses a polishing layer of a chemical mechanical polishing pad and its application, and further studies the polishing layer of the polishing pad. The polishing layer is prepared by reacting an isocyanate prepolymer, a curing agent, and a functional filler; the isocyanate prepolymer is a prepolymer prepared by reacting raw materials of a diisocyanate, a polyether ester polyol, and an optional small molecule polyol; the curing agent is a dispersion formed by a complex of a diamine compound and sodium chloride in dioctyl adipate, and its concentration is 40-50 wt%; the functional filler is an expanded polymer hollow microsphere; while the polishing layer has excellent elasticity and hydrolysis resistance, it also has higher mechanical strength and wear resistance, making the durability of the polishing layer good.

[0005] Chinese Patent CN105415168A discloses a method for preparing a composite polishing pad, which comprises the following steps: (1) Non-woven fabric pretreatment: putting the non-woven fabric into an oven for flattening treatment; dipping the flattened non-woven fabric into a sizing solution, taking it out after complete infiltration to obtain a non-woven fabric substrate; (2) Preparing a polymer solution: dissolving a high molecular elastomer in a solvent to prepare a high molecular elastomer solution; adding polymer particles into the high molecular elastomer solution to obtain a polymer solution; (3) Forming the non-woven fabric into a pad: dipping the non-woven fabric substrate into the polymer solution; taking it out after complete infiltration, scraping off the excess solution on the surface, dipping it into a coagulation bath for solidification molding; then rinsing it in pure water and finally drying it to a constant weight to obtain a raw polishing pad; (4) Forming the polishing pad: after grinding, cutting and gluing the surface of the raw polishing pad, obtaining a finished polishing pad; this polishing pad has a relatively high polishing rate, and at the same time the flatness of the object to be polished is good. However, the scratch resistance and flatness improvement of this polishing pad are limited.

[0006] As is known in the art, using materials with low hardness can effectively reduce the scratches generated during the polishing process, but correspondingly, it will reduce the polishing rate and affect the polishing effect. On the contrary, although substrates and particle materials with high hardness can effectively improve the polishing rate, the number of scratches during the polishing process will also increase. How to achieve an ideal balance among scratches, polishing rate and hardness is crucial for the performance of high-performance polishing pads. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a composite polishing pad, its preparation method and application, and the prepared composite polishing pad has both a high polishing rate and high wear resistance.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] First of all, the present invention provides a composite polishing pad, which comprises components: non-woven fabric, polyester, glycerol monostearate and filler;

[0010] The non-woven fabric is a fiber non-woven fabric treated with a mixed solution of polyacrylamide and glycerol, and the mass ratio of polyacrylamide to glycerol is 20-40:1;

[0011] The polyester is a polyurethane with a molecular weight of 5000-20000;

[0012] The filler is selected from at least one of silica, carbon black, carbon nanotubes and graphene.

[0013] Preferably, the preparation method of the non-woven fabric comprises the steps of: mixing the fiber with a dispersion liquid, performing beating and dispersion, ultrasonic treatment, then wet laying treatment, drying, and hot pressing to obtain the pretreated non-woven fabric; the dispersion liquid is a mixed solution of polyacrylamide and glycerol.

[0014] Further preferably, the mass ratio of the polyacrylamide to glycerol is 30:1.

[0015] Further preferably, the solvent of the dispersion liquid is water.

[0016] Further preferably, the beating dispersion and ultrasonic treatment are specifically as follows: beating and dispersing at 35 - 50 °C, and performing ultrasonic treatment for 2 - 5 min.

[0017] Even more preferably, the beating dispersion and ultrasonic treatment are specifically as follows: beating and dispersing at 40 - 45 °C for 10 - 30 min, and performing ultrasonic treatment for 3 - 4 min.

[0018] Even more preferably, the beating dispersion and ultrasonic treatment are specifically as follows: beating and dispersing at 40 °C for 20 min, and performing ultrasonic treatment for 3 min.

[0019] Further preferably, in the dispersion liquid, the mass concentration of polyacrylamide is 5 - 10%.

[0020] Even more preferably, in the dispersion liquid, the mass concentration of polyacrylamide is 8 - 9%.

[0021] Preferably, the molecular weight of the polyacrylamide is 0.1×10 5 -1×10 5 .

[0022] Further preferably, the molecular weight of the polyacrylamide is 0.5×10 5 .

[0023] Preferably, the mass ratio of the polyurethane to glycerol monostearate is 10:0.5 - 2.

[0024] Further preferably, the mass ratio of the polyurethane to glycerol monostearate is 10:1.

[0025] Preferably, the filler is silica, and the particle size of the silica nanoparticles is 10 - 20 nm.

[0026] Furthermore, the present invention provides a method for preparing a composite polishing pad, comprising the steps of:

[0027] (1) Fiber pretreatment: mixing the fiber with the dispersion liquid, performing wet-laying treatment after beating dispersion and ultrasonic treatment, drying, and hot-pressing to obtain the pretreated non-woven fabric;

[0028] The dispersion liquid is a mixed liquid of polyacrylamide and glycerol;

[0029] (2) Preparing the infiltration liquid:

[0030] (2.1) Mix the polyurethane and glycerol monostearate solution to obtain a polymer solution;

[0031] (2.2) Mix the polymer solution with the filler to obtain an infiltration liquid;

[0032] (3) Pressurized infiltration: Immerse the non-woven fabric in step (1) into the infiltration liquid in step (2), infiltrate under pressure, cool and solidify, and polish the surface to obtain a composite polishing pad.

[0033] Preferably, in step (1), the fiber is a short fiber commonly used for preparing non-woven fabrics, and examples include PET (polyethylene terephthalate) short fibers and PP (polypropylene) short fibers.

[0034] Preferably, in step (1), the beating dispersion and ultrasonic treatment are specifically as follows: Beat and disperse at 35 - 50 °C and perform ultrasonic treatment for 2 - 5 minutes.

[0035] Further preferably, in step (1), the beating dispersion and ultrasonic treatment are specifically as follows: Beat and disperse at 40 - 45 °C for 10 - 30 minutes and perform ultrasonic treatment for 3 - 4 minutes.

[0036] Even more preferably, in step (1), the beating dispersion and ultrasonic treatment are specifically as follows: Beat and disperse at 40 °C for 20 minutes and perform ultrasonic treatment for 3 minutes.

[0037] Preferably, in step (1), the mass ratio of polyacrylamide to glycerol is 20 - 40:1.

[0038] Further preferably, in step (1), the mass ratio of polyacrylamide to glycerol is 30:1.

[0039] Preferably, in step (1), in the dispersion liquid, the mass concentration of polyacrylamide is 5 - 10%.

[0040] Further preferably, in step (1), in the dispersion liquid, the mass concentration of polyacrylamide is 8 - 9%.

[0041] Even more preferably, in step (1), in the dispersion liquid, the mass concentration of polyacrylamide is 8%.

[0042] Preferably, in step (1), the molecular weight of the polyacrylamide is 0.1×10 5 -1×10 5 .

[0043] Further preferably, in step (1), the molecular weight of the polyacrylamide is 0.5×10 5 .

[0044] Preferably, in step (2.1), the mass ratio of the polyurethane to the glycerol monostearate is 10:0.5 - 2.

[0045] More preferably, in step (2.1), the mass ratio of the polyurethane to the glycerol monostearate is 10:1.

[0046] Preferably, in step (2.1), the molecular weight of the polyurethane is 5000 - 20000.

[0047] Preferably, in step (2.1), in the glycerol monostearate solution, the solvent is acetone, and the mass concentration of the glycerol monostearate is 10 - 30%.

[0048] More preferably, the mass concentration of the glycerol monostearate solution is 20%.

[0049] Preferably, in step (2.2), the filler is selected from at least one of silica, carbon black, carbon nanotubes, and graphene.

[0050] More preferably, the filler is silica, the particle size of the silica nanoparticles is 10 - 20 nm; the mass concentration of silica in the silica sol is 30 - 50%.

[0051] More preferably, in step (2.2), in the silica sol, the mass concentration of silica is 35 - 45%.

[0052] Even more preferably, in step (2.2), in the silica sol, the mass concentration of silica is 40%.

[0053] Preferably, in step (2), the mass ratio of the polyurethane, the glycerol monostearate, and the filler is 10:0.5 - 2:0.1 - 0.3.

[0054] More preferably, in step (2), the mass ratio of the polyurethane, the glycerol monostearate, and the filler is 10:1:0.2.

[0055] Preferably, in step (3), the infiltration under pressure is specifically: infiltration for 10 - 20 min under a pressure of 0.1 - 0.2 MPa.

[0056] More preferably, in step (3), the infiltration under pressure is specifically: infiltration for 15 min under a pressure of 0.15 MPa

[0057] Finally, the present invention provides the application of the above composite polishing pad or the composite polishing pad prepared by the above preparation method in wafer polishing treatment.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] 1. The non-woven fabric in the composite polishing pad of the present invention is a fiber non-woven fabric treated with a mixed solution of polyacrylamide and glycerol. By performing auxiliary pretreatment of beating and dispersing the fibers and ultrasonic treatment, not only can the dispersion uniformity of the non-woven fabric be improved, but also the polishing performance of the obtained polishing pad is improved, with a high polishing rate and few scratches generated during the polishing process.

[0060] 2. The non-woven fabric in the composite polishing pad of the present invention has a high porosity, which is beneficial to the infiltration of the infiltration liquid during the subsequent infiltration process, and the hardness, polishing rate, and density of the polishing pad are improved.

[0061] 3. By controlling the particle size of the filler, the present invention enables the filler to be efficiently attached to the pores of the non-woven fabric. While ensuring the hardness, polishing performance, and flatness of the polishing pad, it reduces the friction and scratches on the device. At the same time, using polyurethane and glycerol monostearate as the polymer solution can efficiently achieve the infiltration of the non-woven fabric, improve the flatness of the polishing pad, and reduce the surface roughness of the polishing pad. Specific Embodiments

[0062] The following non-limiting embodiments can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary illustration of the scope claimed by the present invention. Those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and it should also fall within the scope claimed by the present invention. When the embodiments give a numerical range, it should be understood that unless otherwise specified by the present invention, any value between the two endpoints of each numerical range and any value between them can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0063] The present invention will be further described below by way of specific embodiments. All chemical reagents used in the embodiments of the present invention are obtained through conventional commercial channels unless otherwise specified. Products from different manufacturers do not have a significant impact on the effects.

[0064] In the following embodiments, the polyurethane is a commercially available industrial product (C 14 H 26 N 2 O 5 ); the polyacrylamide (molecular weight 5000 - 20000) and glycerol monostearate are both purchased from Aladdin Reagent Company.

[0065] Example 1

[0066] A method for preparing a composite polishing pad, comprising the steps:

[0067] (1) Fiber pretreatment: Mix the polypropylene staple fiber with the dispersion liquid, beat and disperse it at 40 °C for 20 min, perform wet-laying treatment after ultrasonic treatment for 3 min, dry it, and hot-press it to obtain the pretreated non-woven fabric;

[0068] The dispersion liquid is a mixed liquid of polyacrylamide and glycerol. The mass ratio of polyacrylamide to glycerol is 30:1. The mass concentration of polyacrylamide in the dispersion liquid is 8%, and the dispersion liquid solvent is water;

[0069] The average molecular weight of the polyacrylamide is 0.5×10 5 ;

[0070] (2) Preparation of the infiltration liquid:

[0071] (2.1) Dissolve glycerol monostearate in acetone to obtain a glycerol monostearate solution with a mass concentration of 20%. Mix the polyurethane emulsion and the glycerol monostearate solution. The mass ratio of the polyurethane emulsion to glycerol monostearate is 10:1 to obtain a polymer solution;

[0072] (2.2) Mix the polymer solution with the silica sol to obtain the infiltration liquid; in the silica sol, the particle size of the silica nanoparticles is 10 - 20 nm, and the mass concentration of silica is 40%; the mass ratio of polyurethane, glycerol monostearate, and silica is 10:1:0.2;

[0073] (3) Pressurized infiltration: Immerse the pretreated non-woven fabric in step (1) into the infiltration liquid in step (2), infiltrate it at a pressure of 0.15 MPa for 15 min, cool and solidify after complete infiltration, and polish the surface to obtain the composite polishing pad.

[0074] Example 2

[0075] A preparation method of a composite polishing pad, comprising the steps:

[0076] (1) Fiber pretreatment: Mix the polypropylene staple fiber with the dispersion liquid, beat and disperse it at 45 °C for 20 min, perform wet-laying treatment after ultrasonic treatment for 4 min, dry it, and hot-press it to obtain the pretreated non-woven fabric;

[0077] The dispersion liquid is a mixed liquid of polyacrylamide and glycerol. The mass ratio of polyacrylamide to glycerol is 30:1. The mass concentration of polyacrylamide in the dispersion liquid is 9%, and the dispersion liquid solvent is water;

[0078] The average molecular weight of the polyacrylamide is 0.5×10 5 ;

[0079] (2) Preparation of the infiltration liquid:

[0080] (2.1) Dissolve glycerol monostearate in acetone to obtain a glycerol monostearate solution with a mass concentration of 30%. Mix the polyurethane emulsion and the glycerol monostearate solution. The mass ratio of the polyurethane emulsion to glycerol monostearate is 10:2 to obtain a polymer solution.

[0081] (2.2) Mix the polymer solution with the silica sol to obtain an infiltration liquid. In the silica sol, the particle size of the silica nanoparticles is 10 - 20 nm, and the mass concentration of silica is 40%. The mass ratio of polyurethane, glycerol monostearate, and silica is 10:2:0.3.

[0082] (3) Pressurized infiltration: Immerse the non-woven fabric pretreated in step (1) into the infiltration liquid in step (2), infiltrate for 15 min under a pressure of 0.15 MPa, cool and solidify after complete infiltration, and polish the surface to obtain a composite polishing pad.

[0083] Example 3

[0084] A preparation method of a composite polishing pad, comprising the steps:

[0085] (1) Fiber pretreatment: Mix the polypropylene short fibers with the dispersion liquid, beat and disperse at 35 °C for 20 min, perform wet laying after ultrasonic treatment for 5 min, dry, and hot press to obtain the pretreated non-woven fabric.

[0086] The dispersion liquid is a mixed liquid of polyacrylamide and glycerol. The mass ratio of polyacrylamide to glycerol is 20:1. The mass concentration of polyacrylamide in the dispersion liquid is 5%, and the dispersion liquid solvent is water.

[0087] The average molecular weight of the polyacrylamide is 0.5×10 5 ;

[0088] (2) Prepare the infiltration liquid:

[0089] (2.1) Dissolve glycerol monostearate in acetone to obtain a glycerol monostearate solution with a mass concentration of 10%. Mix the polyurethane emulsion and the glycerol monostearate solution. The mass ratio of the polyurethane emulsion to glycerol monostearate is 10:0.5 to obtain a polymer solution.

[0090] (2.2) Mix the polymer solution with the silica sol to obtain an infiltration liquid. In the silica sol, the particle size of the silica nanoparticles is 10 - 20 nm, and the mass concentration of silica is 40%. The mass ratio of polyurethane, glycerol monostearate, and silica is 10:0.5:0.1.

[0091] (3) Pressurization and infiltration: Immerse the non-woven fabric pretreated in step (1) into the infiltration liquid in step (2), infiltrate for 20 min under a pressure of 0.1 MPa, after complete infiltration, cool and solidify, and polish the surface to obtain a composite polishing pad.

[0092] Example 4

[0093] A preparation method of a composite polishing pad, comprising the steps:

[0094] (1) Fiber pretreatment: Mix polypropylene staple fibers with a dispersion liquid, beat and disperse at 50 °C for 10 min, perform wet laying treatment after ultrasonic treatment for 3 min, dry and hot press to obtain the pretreated non-woven fabric;

[0095] The dispersion liquid is a mixed liquid of polyacrylamide and glycerol, the mass ratio of polyacrylamide to glycerol is 40:1, the mass concentration of polyacrylamide in the dispersion liquid is 10%, and the dispersion liquid solvent is water;

[0096] The average molecular weight of the polyacrylamide is 0.5×10 5 ;

[0097] (2) Preparation of the infiltration liquid:

[0098] (2.1) Dissolve glycerol monostearate in acetone to obtain a glycerol monostearate solution with a mass concentration of 20%, mix the polyurethane emulsion and the glycerol monostearate solution, and the mass ratio of the polyurethane emulsion to glycerol monostearate is 10:1 to obtain a polymer solution;

[0099] (2.2) Mix the polymer solution with silica sol to obtain an infiltration liquid; in the silica sol, the particle size of the silica nanoparticles is 10 - 20 nm, and the mass concentration of silica is 40%; the mass ratio of polyurethane, glycerol monostearate and silica is 10:1:0.2;

[0100] (3) Pressurization and infiltration: Immerse the non-woven fabric pretreated in step (1) into the infiltration liquid in step (2), infiltrate for 10 min under a pressure of 0.2 MPa, cool and solidify, and polish the surface to obtain a composite polishing pad.

[0101] Comparative Example 1

[0102] Different from Example 1, the fiber pretreatment step in step (1) was not carried out, and the preparation of the non-woven fabric was directly carried out. The specific steps are as follows:

[0103] (1) Non-woven fabric preparation: Immerse polypropylene staple fibers in water for 23 min, perform wet laying treatment, dry and hot press to obtain a polypropylene staple fiber non-woven fabric;

[0104] (2) Preparation of the infiltration liquid:

[0105] (2.1) Dissolve glycerol monostearate in acetone to obtain a glycerol monostearate solution with a mass concentration of 20%. Mix the polyurethane emulsion and the glycerol monostearate solution. The mass ratio of the polyurethane emulsion to glycerol monostearate is 10:1 to obtain a polymer solution.

[0106] (2.2) Mix the polymer solution with the silica sol to obtain an infiltration liquid. In the silica sol, the particle size of the silica nanoparticles is 10 - 20 nm, and the mass concentration of silica is 40%. The mass ratio of polyurethane, glycerol monostearate, and silica is 10:1:0.2.

[0107] (3) Pressurized infiltration: Immerse the non - woven fabric in step (1) into the infiltration liquid in step (2), infiltrate for 15 min under a pressure of 0.15 MPa. After complete infiltration, cool and solidify, and polish the surface to obtain a composite polishing pad.

[0108] Comparative Example 2

[0109] Different from Example 1, glycerol is not added to the dispersion liquid in step (1), and the dispersion liquid only contains the component polyacrylamide. In this comparative example, the dispersion liquid is an aqueous polyacrylamide solution with a mass concentration of 8%.

[0110] The rest are the same as in Example 1.

[0111] Comparative Example 3

[0112] Different from Example 1, in the polymer solution in step (2.1), the glycerol monostearate solution is not added. In this comparative example, the polymer solution is a polyurethane emulsion.

[0113] The rest are the same as in Example 1.

[0114] Comparative Example 4

[0115] Different from Example 1, in the polymer solution in step (2.1), the mass ratio of the polyurethane emulsion to glycerol monostearate is 4:1; the rest are the same as in Example 1.

[0116] Comparative Example 5

[0117] Different from Example 1, in the silica sol in step (2.2), the particle size of the silica nanoparticles is 30 - 50 nm. The rest are the same as in Example 1.

[0118] Comparative Example 6

[0119] Prepare the composite polishing pad according to the preparation method described in Example 1 of Chinese invention patent CN105415168A.

[0120] Performance Detection Test

[0121] 1. Hardness Detection

[0122] It is carried out according to the detection standard of "GB / T 2411-2008 Test Method for Shore Hardness of Plastics". The hardness of the composite polishing pads prepared in the examples and comparative examples is detected by a Type A Shore hardness tester. The parallel test is carried out 3 times, and the detection results are shown in Table 1.

[0123] 2. Density Detection

[0124] Weigh the mass m of the composite polishing layer, and measure the volume v of the composite polishing layer. The value of m / v is the overall density of the composite polishing layer. The parallel test is carried out 3 times, and the detection results are shown in Table 1.

[0125] 3. Polishing Rate Detection

[0126] The composite polishing pads obtained in the examples and comparative examples are cut (the cutting size is 18 in), and then a diamond graphite disk is used for 15 minutes of flocking treatment and surface finishing. Under the conditions of a grinding disk rotation speed of 50 r / min and a polishing pressure of 21.2 kPa, the polishing liquid is supplied at a speed of 100 mL / min, and a 4 in wafer is polished for 2 minutes. After polishing, measure the thickness of any 49 points in the wafer plane and divide it by the polishing time to obtain the polishing rate (nm / min) of each point. The average value of the polishing rates of the 49 points is recorded as the polishing rate R. The detection results are shown in Table 1.

[0127] The greater the polishing rate, the shorter the required polishing time and the better the polishing performance.

[0128] 4. Scratch Performance Evaluation

[0129] An optical microscope is used to observe surface defects (scratches), and the number of scratches with a length greater than 0.16 μm on the wafer polishing surface is detected and recorded. The parallel test is carried out 5 times, and the scratch performance evaluation results are shown in Table 1.

[0130] The more scratches, the worse the polishing performance of the polishing pad.

[0131] 5. Surface Roughness Detection

[0132] The surface roughness Ra is detected by a Bruker Dimension ICon atomic force microscope AFM, with a vertical resolution of (angstrom), a horizontal resolution of 0.1 nm, and a scanning range of 5 μm × 5 μm. The parallel test is carried out 3 times. The surface roughness Ra results are shown in Table 1.

[0133] The larger the Ra value, the worse the performance of the polishing pad.

[0134] Table 1

[0135]

[0136] Among the data in the same column of Table 1, compared with Example 1, the comparative example shows: *P≤0.05, **P≤0.01, indicating significant differences. It can be seen from Table 1 that the composite polishing pad obtained by the preparation method of the embodiment of the present invention has excellent hardness and polishing rate; the present invention pre-treats the fibers, resulting in a significant reduction in the number of scratches on the wafer when the composite polishing pad acts on it; the addition of glycerol in the dispersion can also improve the effect on the fibers and polyacrylamide, thereby increasing the polishing rate.

[0137] In the process of preparing the composite polishing pad, the present invention infiltrates the pre-treated fibers in an infiltration liquid with specific components under pressure, and combines the fibers with polyurethane, so that the composite polishing pad has excellent mechanical strength and wear resistance. Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement of the technical solution of the present invention by those of ordinary skill in the art does not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A composite polishing pad, characterized in that: Comprising components: non-woven fabric, polyester, glyceryl monostearate and filler; The non-woven fabric is a fiber non-woven fabric treated with a mixture of polyacrylamide and glycerol, wherein the mass ratio of polyacrylamide to glycerol is 20-40:1; The polyester is a polyurethane with a molecular weight of 5000-20000; the mass ratio of the polyurethane to glyceryl monostearate is 10:0.5-2; The filler is silicon dioxide, and the particle size of silicon dioxide nanoparticles is 10-20nm.

2. The composite polishing pad according to claim 1, characterized in that: The preparation method of the non-woven fabric comprises the steps of: mixing fibers with a dispersion liquid, dispersing by beating, and performing a wet web forming process after ultrasonic treatment, drying, and hot pressing to obtain a pre-treated non-woven fabric; the dispersion liquid is a mixture of polyacrylamide and glycerol.

3. The composite polishing pad according to claim 2, characterized in that: In the dispersion, the mass ratio of polyacrylamide to glycerol is 30:1; the mass concentration of polyacrylamide is 5-10%; The beating and dispersing and ultrasonic treatment are specifically: beating and dispersing at 35-50° C. and ultrasonic treatment for 2-5 minutes.

4. The composite polishing pad according to claim 1, characterized in that: The molecular weight of the polyacrylamide is 0.1×10 5 -1×10 5 .

5. The composite polishing pad according to claim 4, characterized in that: The mass ratio of the polyurethane to glyceryl monostearate is 10:

1.

6. The method for preparing the composite polishing pad according to any one of claims 1 to 5, characterized in that: Includes steps: (1) Fiber pretreatment: The fibers are mixed with a dispersion liquid, and then subjected to pulping dispersion, ultrasonic treatment, wet web forming, drying, and hot pressing to obtain a pretreated nonwoven fabric; The dispersion liquid is a mixture of polyacrylamide and glycerol; (2) Preparation of infiltration solution: (2.1) mixing polyurethane and glyceryl monostearate solution to obtain a polymer solution; (2.2) mixing the polymer solution with the filler to obtain an impregnation solution; (3) Pressurized impregnation: the non-woven fabric of step (1) is impregnated into the impregnation liquid of step (2), impregnated under pressure, cooled and solidified, and the surface is polished to obtain a composite polishing pad.

7. The preparation method according to claim 6, characterized in that: In step (1), the beating and dispersing and ultrasonic treatment are specifically: beating and dispersing at 35-50° C. and ultrasonic treatment for 2-5 minutes; In step (1), in the dispersion, the mass concentration of polyacrylamide is 5-10%, the mass ratio of polyacrylamide to glycerol is 20-40:1; the molecular weight of the polyacrylamide is 0.1×10 5 -1×10 5 .

8. The preparation method according to claim 6, characterized in that: In step (2.1), the mass ratio of the polyurethane to glyceryl monostearate is 10:0.5-2; The molecular weight of the polyurethane is 5000-20000; In the glyceryl monostearate solution, the solvent is acetone, and the mass concentration of glyceryl monostearate is 10-30%.

9. The preparation method according to claim 6, characterized in that: In step (2.2), when the filler is silicon dioxide, the particle size of the silicon dioxide nanoparticles is 10-20 nm, and the mass concentration of silicon dioxide is 30-50%; In step (2), the mass ratio of the polyurethane, glyceryl monostearate and filler is 10:0.5-2:0.1-0.3; In step (3), the infiltration under pressure is specifically: infiltration under a pressure of 0.1-0.2 MPa for 10-20 min.

10. Use of the composite polishing pad according to any one of claims 1 to 5 or the composite polishing pad prepared by the preparation method according to any one of claims 6 to 9 in wafer polishing.

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