Polishing cushion and manufacturing method thereof, and manufacturing method of semiconductor device

Abstract

The present invention relates to a polishing pad, a method for manufacturing the same, and a method for manufacturing a semiconductor device. The polishing pad includes a first isocyanate, a second diisocyanate different from the first isocyanate, a polyether polyol, a chain extender, and a reinforcing material. Wherein the chain extender is hydrazine hydrate; the reinforcing material is a combination of ternary hydroxyl vinyl chloride-vinyl acetate resin and binary vinyl chloride-vinyl acetate resin. In addition, the mass fraction of the reinforcing material is 25-45 wt%, and the elastic modulus is 50-100 MPa. The polishing cushion provided by the invention is high in elastic modulus, high in removal rate and long in accumulative service life, the surface defect of a wafer polished by the polishing cushion is low, and the polishing cushion is suitable for a fine polishing process.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical planarization technology, specifically relating to a polishing pad and its preparation method, as well as a method for manufacturing a semiconductor device. Background Technology

[0002] With the continuous increase in the integration level of integrated circuits, chip manufacturing processes face increasingly stringent precision requirements. Chemical mechanical polishing (CMP), as a critical process, directly impacts chip yield and production efficiency through the performance of its core consumable—the polishing pad. Against this backdrop, polyurethane-based polishing pads have become a focus of the industry due to their unique material advantages. This polymer can be customized with diverse properties through molecular design, possessing excellent impact resistance, wear resistance, and fracture toughness, while also offering high processing flexibility and adaptability to complex requirements through curing process control.

[0003] However, traditional polyurethane polishing pads typically use polyester polyols or polyether polyols as soft segments and isocyanates and chain extenders as hard segments, generally resulting in low modulus. This significantly limits their application in polishing. While some materials incorporate reinforcing materials to enhance their mechanical properties, these are mostly inorganic powders such as silica, zinc oxide, and carbon black, with limited addition amounts and poor compatibility, failing to meet requirements. Furthermore, the resulting polishing pads suffer from insufficient removal efficiency, and their wear resistance is insufficient for high-intensity continuous production, necessitating an improvement in service life. With the rapid penetration of composite material technology into various fields, the market has raised the bar for the mechanical strength of polyurethane polishing pads. Developing new polyurethane systems that combine high modulus, high strength, and excellent toughness, breaking through the performance boundaries of existing materials, has become a key technological breakthrough for expanding their applications in precision manufacturing. This will directly drive the upgrade of CMP polishing pads towards high efficiency and long lifespan. Summary of the Invention

[0004] This application provides a polishing pad and its preparation method, as well as a semiconductor device manufacturing method. The polishing pad is used in fine polishing processes and has high modulus and removal rate, good wear resistance, long service life, and low wafer defects after polishing.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, this application provides a polishing pad, comprising a polishing layer, wherein the polishing layer is made of a first isocyanate, a second isocyanate different from the first isocyanate, a polyether polyol, a chain extender, and a reinforcing material; the chain extender is hydrazine hydrate; the reinforcing material is a combination of a ternary hydroxyl vinyl acetate resin and a dichlorovinyl acetate resin; the mass fraction of the reinforcing material is 25-45 wt%; and the elastic modulus of the polishing pad is 50-100 MPa.

[0007] In some possible embodiments, the molar ratio of the ternary hydroxyl chloroacetic acid resin to the binary chloroacetic acid resin is 0.5 to 1.5:1, preferably 1:1.

[0008] In some possible embodiments, the proportion of each repeating unit in the ternary hydroxychlorovinyl acetate resin is: vinyl chloride 75-95%, vinyl acetate 2-15%, and vinyl alcohol 3-15%; preferably: vinyl chloride 80-93%, vinyl acetate 3-10%, and vinyl alcohol 5-10%.

[0009] In some possible embodiments, the proportion of each repeating unit in the binary vinyl chloride-vinyl acetate resin is 75-95% vinyl chloride and 5-25% vinyl acetate; preferably, it is 80-90% vinyl chloride and 10-20% vinyl acetate.

[0010] In some possible embodiments, the first isocyanate and the second isocyanate are selected from toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; preferably, the first isocyanate is diphenylmethane diisocyanate and the second isocyanate is toluene diisocyanate.

[0011] In some possible implementations, the polyether polyol is selected from at least one of polybutanediol, polypropylene glycol, and polyethylene glycol.

[0012] In some possible implementations, the isocyanate index R = 1.01~1.03; the chain extender accounts for 22~28% of the molar percentage of the first isocyanate, the second isocyanate, the polyether polyol and the chain extender.

[0013] Secondly, this application provides a method for preparing a polishing pad, comprising the following steps:

[0014] S1. Prepolymerization: Polyether polyol reacts with the first isocyanate at 90 °C for 3 h. After the reaction is completed, the temperature is lowered to 60 °C, the second isocyanate is added, and the reaction is continued for 2 h. Then, the solvent N,N-dimethylformamide is added, and the system is diluted to a prepolymer solution with a solid content of 25~35%.

[0015] S2. Chain extension: Cool the prepolymer solution to room temperature, slowly add the chain extender solution to carry out the chain extension reaction;

[0016] S3. Reinforcement: When the molecular weight of the detection system increases to between 80,000 and 100,000, add a reinforcing material solution, surfactant, etc., and stir evenly to obtain a polishing layer mixed slurry.

[0017] S4. Molding: The polishing layer mixture is coated onto a non-woven fabric substrate, immersed in a coagulation liquid, and after coagulation, it is washed with water, sanded, embossed, and bonded with adhesive backing to obtain the polishing pad as described in any one of claims 1 to 7.

[0018] In some possible embodiments, the solvent in the chain extender solution is N,N-dimethylformamide, and the mass ratio of the chain extender to the solvent is 1:10; the solvent in the reinforcing material solution is N,N-dimethylformamide, and the mass ratio of the reinforcing material to the solvent is 1:3; the main components of the coagulation liquid include at least one of water, ethanol, methanol, and isopropanol.

[0019] Thirdly, this application provides a method for manufacturing a semiconductor device, including a step of finely polishing the surface of a semiconductor wafer using a polishing pad provided in the first aspect of this application.

[0020] Beneficial effects:

[0021] 1. Using a high-hardness vinyl chloride resin as a reinforcing material, a combination of physical blending and chemical modification is employed to graft a ternary hydroxyl vinyl chloride resin onto the polyurethane resin backbone. This significantly enhances the compatibility of the binary vinyl chloride resin and polyurethane resin system, synergistically promoting the reinforcing effect of physical blending. Compared to traditional small-molecule alcohol chain extenders that extend chains via urethane bonds, the chain extender in this invention, hydrazine hydrate, forms urea bonds with NCO with higher bond energy and greater strength, improving the mechanical strength of the polishing pad at the molecular structure level. The synergistic reinforcing effect of the combination of chemical and physical modification, along with the chain extension method using stronger urea bonds, significantly improves the removal rate and wear resistance of the polishing pad, extending its service life.

[0022] 2. By using a two-component isocyanate, the mechanical strength of the polyurethane resin is improved while the regularity of the long resin chain is disrupted to a certain extent, the crystallinity is reduced, and the wettability and compatibility of the resin with the coating substrate are improved. Combined with the preparation method of this application, the elastic modulus of the polishing pad is further improved. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only a part of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a SEM image of the cross-section of the polished pad after embossing in Embodiment 1 of this application. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and not to limit the scope of the invention. Specific conditions not specified in the examples shall be carried out under conventional conditions or the manufacturer's recommended conditions. If the manufacturers of the reagents or instruments used are not specified, they can be conventional products that are commercially available or purchased.

[0026] Polishing Pad

[0027] In this embodiment, a first aspect provides a polishing pad, the raw materials of which include a first isocyanate, a second isocyanate different from the first isocyanate, a polyether polyol, a chain extender, and a reinforcing material.

[0028] Isocyanates

[0029] In this embodiment, two isocyanates are included: a first isocyanate and a second isocyanate, which is different from the first isocyanate. Both the first and second isocyanates are selected from diphenylmethane diisocyanate, toluene diisocyanate, and isophorone diisocyanate.

[0030] This embodiment uses a two-component isocyanate. Isocyanates with different substitution structures can disrupt the regularity of the polyurethane resin chain to a certain extent during the polymerization reaction, reduce crystallinity, enhance the interaction between the polyurethane resin and the coating substrate, and improve the mechanical properties of the polishing pad.

[0031] The preferred isocyanate in this embodiment has a benzene ring with high rigidity or a relatively stable six-membered ring, which can improve the mechanical strength of polyurethane resin from the molecular structure.

[0032] From the perspective of improving mechanical properties, in this embodiment, the first isocyanate is particularly preferably diphenylmethane diisocyanate, and the second isocyanate is particularly preferably toluene diisocyanate.

[0033] In this embodiment, in order to balance the materials, the isocyanate index R is controlled to be 1.01~1.03, so that NCO is slightly in excess, and active sites are reserved for chemical modification with ternary hydroxychloroester resin, so as to obtain a polishing pad with suitable elastic modulus, fewer polishing defects and excellent comprehensive performance.

[0034] Chain extender

[0035] The chain extender in this embodiment differs from traditional small-molecule polyol chain extenders. Traditional small-molecule polyol chain extenders react with NCO in the prepolymer to form urethane, while the chain extender in this embodiment, hydrazine hydrate, can react with free NCO to extend the chain through urea bonds. Urea bonds have higher bond energy and stronger strength, thereby enhancing the modulus of the polishing pad and improving the removal rate and wear resistance.

[0036] In this embodiment, the chain extender accounts for 22.5-27.5% of the molar percentage of the first isocyanate, the second isocyanate, the polyether polyol, and the chain extender. If the amount of chain extender added is too low, the molecular weight of the polyurethane resin is insufficient, and good flexibility cannot be achieved; if the amount added is too high, the crosslinking density is too high, the hardness is too high, and it may cause defects on the wafer surface.

[0037] Reinforcing materials

[0038] Due to the properties of polyurethane materials, some polishing pads incorporate additional reinforcing materials to enhance their mechanical properties, mostly inorganic materials such as calcium carbonate, silica, and carbon black. However, the amount of inorganic reinforcing materials added is limited, and their compatibility is poor, resulting in very limited improvement in the removal rate. In this embodiment, organic materials are used, with the reinforcing material being a combination of ternary hydroxyl vinyl acetate resin and binary vinyl acetate resin.

[0039] In this embodiment, the binary vinyl chloride-vinyl acetate resin is copolymerized from vinyl chloride and vinyl acetate, and is mostly composed of polyvinyl chloride segments, thus exhibiting high strength similar to polyvinyl chloride. However, due to the poor compatibility between vinyl chloride-vinyl acetate resin and polyurethane, if it is directly added to the polyurethane system through physical blending, the improvement on the mechanical properties of the polyurethane system is not significant.

[0040] In this embodiment, the ternary hydroxyl chloride resin is copolymerized from vinyl chloride, vinyl acetate, and a small amount of vinyl alcohol. Besides possessing the strength of binary hydroxyl chloride resins, it also contains a small amount of active hydroxyl groups, which can react with the free NCO in the polyurethane resin. The inventors of this application attempted to graft the ternary hydroxyl chloride resin onto the polyurethane resin system, attempting to improve the mechanical strength of the polyurethane resin system through chemical modification. However, the improvement in the mechanical properties of the polyurethane resin system is related to the grafting amount of the ternary hydroxyl chloride resin. When using a ternary hydroxyl chloride resin with a low polyvinyl alcohol fragment content for modification, the grafting amount is low, and the improvement in mechanical properties is not significant. Increasing the content of active hydroxyl groups in polyvinyl alcohol easily leads to excessive cross-linking and hardness in the polyurethane resin system, resulting in severe surface defects on the wafer after treatment, failing to meet the requirements for the softness of the polishing pad in the fine polishing process.

[0041] The inventors of this application discovered that combining two modification methods significantly improves the mechanical properties of the polyurethane system. They speculate that the principle behind this improvement may be that the polyurethane resin partially grafted with ternary hydroxyl chloride resin can enhance the compatibility between the binary hydroxyl chloride resin and the polyurethane resin system, synergistically promoting the reinforcing effect of physical blending. In this embodiment, the synergistic reinforcing effect of combining chemical and physical modification can significantly improve the removal rate and wear resistance of the polishing pad, extending its service life in the fine polishing process.

[0042] In this embodiment, the proportion of each repeating unit in the binary chloroacetic acid resin is: vinyl chloride 75-95%, vinyl acetate 5-25%. Considering both improving mechanical properties and promoting compatibility, the preferred proportion of each repeating unit in the binary chloroacetic acid resin is: vinyl chloride 80-90%, vinyl acetate 10-20%. The proportion of each repeating unit in the ternary hydroxyl chloroacetic acid resin is: vinyl chloride 75-95%, vinyl acetate 2-15%, vinyl alcohol 3-15%. Considering both promoting compatibility and reducing defects, the preferred proportion of each repeating unit in the ternary chloroacetic acid resin is: vinyl chloride 80-93%, vinyl acetate 3-10%, vinyl alcohol 5-10%. Simultaneously, to achieve the best synergistic effect of physical blending and chemical modification, the total mass fraction of the reinforcing material is controlled at 35%, wherein the molar ratio of the ternary hydroxyl chloroacetic acid resin to the binary chloroacetic acid resin is 0.5-1.5:1, preferably 1:1.

[0043] In this embodiment, the total mass fraction of the two chloroacetic acid resins is 25~45wt%. If the amount added is too low, the reinforcing effect is not good. If the amount added is too high, it will affect the flexibility of the polishing pad and easily cause defects on the wafer surface.

[0044] Polyether polyols

[0045] In this embodiment, polyether polyol is preferred as the soft segment of polyurethane. It has low cohesive energy of ether bonds, good low-temperature flexibility, and good miscibility with isocyanate. It can reduce the glass transition temperature of polyurethane resin, improve the flexibility and resilience of polishing pads, reduce wafer surface defects, and meet the requirements of fine polishing.

[0046] In this embodiment, the polyether polyol can be exemplified as follows: at least one of polybutanediol, polypropylene glycol, polyethylene glycol, and polypropylene glycol-ethylene glycol copolymer.

[0047] In this embodiment, the molecular weight of the polyether polyol is 500~3000, preferably 800~1500.

[0048] Polishing pad

[0049] In this embodiment, in order to obtain a higher removal rate, improve wear resistance in the fine polishing process, and extend the polishing time, the elastic modulus of the polishing pad is 50~100 MPa, preferably 60~80 MPa.

[0050] <Preparation method of polishing pad>

[0051] The second aspect of this embodiment provides a method for preparing a polishing pad, comprising the following steps:

[0052] S1. Prepolymerization: Polyether polyol reacts with the first isocyanate at 90 °C for 3 h. After the reaction is completed, the temperature is lowered to 60 °C, the second isocyanate is added, and the reaction is continued for 2 h. Then, the solvent N,N-dimethylformamide is added, and the system is diluted to a prepolymer solution with a solid content of 25~35%.

[0053] In this embodiment, the reaction process is carried out by slow and uniform stirring, with the rotation speed controlled at 60 rpm. Diluting the system to a prepolymer solution with a solid content of 25-35% helps to control the viscosity and rheology of the mixed slurry during the coating process, which is beneficial for uniform coating and curing.

[0054] S2. Chain extension: Cool the prepolymer solution to room temperature, slowly add the chain extender solution to carry out the chain extension reaction;

[0055] In this embodiment, the solvent in the chain extender solution is N,N-dimethylformamide, and the mass ratio of the chain extender to the solvent is 1:10. Adding the chain extender after dilution helps to control the reaction process, adjust the molecular weight and its distribution, and avoid explosive polymerization.

[0056] S3. Reinforcement: When the molecular weight of the detection system increases to between 80,000 and 100,000, add a reinforcing material solution, surfactant, etc., and stir evenly to obtain a polishing layer mixed slurry.

[0057] In this embodiment, the solvent in the reinforcing material solution is N,N-dimethylformamide, and the mass ratio of the reinforcing material to the solvent is 1:3. After diluting the reinforcing material, a mixed slurry that is conducive to forming chemical modification and physical blending uniformity is added, thereby improving the uniformity and mechanical strength of the polishing pad after curing.

[0058] S4. Molding: The polishing layer mixture is coated onto a non-woven fabric substrate, immersed in a coagulation liquid, and after coagulation, it is washed with water, sanded, embossed, and bonded with adhesive backing to obtain the polishing pad provided in the first aspect of this embodiment.

[0059] In this embodiment, a phase separation curing method is employed. The main components of the coagulating liquid include at least one of water, ethanol, methanol, and isopropanol. These components have poor solubility in polyurethane, which promotes rapid phase transfer and curing of the mixed slurry. Since processes such as washing, sanding, embossing, and adhesive bonding are relatively conventional and not the focus of this application, detailed processes will not be described here. For specific details, please refer to existing technologies.

[0060] <Semiconductor Device Manufacturing Methods>

[0061] The third aspect of this embodiment provides a method for manufacturing a semiconductor device, including a step of finely polishing the surface of a semiconductor wafer using a polishing pad provided in the first aspect of this embodiment.

[0062] Example

[0063] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as specific limitations thereof.

[0064] Explanation of reference numerals in the embodiments:

[0065] PTMG: Polybutanediol

[0066] TDI: Toluene diisocyanate

[0067] MDI: Diphenylmethane diisocyanate

[0068] IPDI: Isophorone diisocyanate

[0069] MDA: 4,4'-Diaminodiphenylmethane

[0070] EG: Ethylene glycol

[0071] DMF: N,N-dimethylformamide;

[0072] In this embodiment, all chloroacetic acid resins were purchased from Nissin Chemical. The ternary hydroxyl chloroacetic acid resin grades were A-type, TA5R, and TA3; the binary chloroacetic acid resin grades were C-type, CLL2, and C5R. Other raw materials were all from commercially available bulk industrial products, and manufacturers included BASF, Wanhua Chemical, Asahikawa Chemical, and Huafeng.

[0073] The performance parameter measurement methods involved in this embodiment are as follows:

[0074] Elastic modulus test

[0075] Refer to national standard GB / T 1040.3-2006; universal testing machine model: AGX-V2.

[0076] Removal rate evaluation

[0077] The removal rate during the polishing process was recorded using a four-probe film thickness gauge (NAPSON Crestest / RG3000), and the average value was calculated.

[0078] Defect evaluation

[0079] Defects on the material after polishing the substrate are inspected using the Surfscan® SP2 defect inspection system available from KLA-Tencor. The defect size is 0.16 μm. ○○ indicates almost no defects, ○ indicates very few defects, × indicates a few defects, ×× indicates many defects, and ××× indicates a large number of serious defects.

[0080] Service life evaluation

[0081] The examples and comparative examples were subjected to wafer planar polishing tests, and their maximum service life was recorded.

[0082] Example 1

[0083] S1. Prepolymerization: Polyether polyol (PTMG, molecular weight 1000) and second isocyanate (TDI) are reacted at 90 °C for 3 h. After the reaction is completed, the temperature is lowered to 60 °C, and first isocyanate (MDI) is added. The molar ratio of first isocyanate (MDI), second isocyanate (TDI), and polyether polyol (PTMG) is controlled at 3:1:2. After the reaction continues for 2 h, solvent N,N-dimethylformamide is added to dilute the system to a prepolymer solution with a solid content of 30%. The reaction is carried out by slow and uniform stirring, with the stirring speed controlled at 60 rpm.

[0084] S2. Chain extension: Cool the prepolymer solution to room temperature, and slowly add a chain extender solution with a mass ratio of hydrazine hydrate to DMF of 1:10, wherein the molar percentage of hydrazine hydrate is 25%, and the isocyanate index is controlled at 1.03 to carry out the chain extension reaction.

[0085] S3. Reinforcement: When the molecular weight of the detection system increases to 75,000, a reinforcement material solution with a mass ratio of 1:3 to DMF, surfactants, etc. are added. The ratio of ternary hydroxyl chloroacetic acid resin to binary chloroacetic acid resin is 1:1 and accounts for 35% of the total mass fraction. The mixture is stirred evenly to obtain the polishing layer slurry.

[0086] S4. Molding: The polishing layer mixture is coated onto a non-woven fabric substrate and immersed in a coagulation liquid whose main component is water. After coagulation, the substrate is washed, sanded, embossed, and bonded with adhesive backing to obtain a polishing pad.

[0087] The preparation methods of Examples 2-5 and Comparative Examples 1-5 are the same as those of Example 1, except that the raw materials or proportions are different. The specific differences are shown in Table 1.

[0088] Table 1. Raw materials and proportions of polishing pads in Examples 1-5 and Comparative Examples 1-5

[0089]

[0090] Table 2 Evaluation results of polishing pads in Examples 1-5 and Comparative Examples 1-5

[0091]

[0092] Table 1 shows the adjusted ratio and block content of the reinforcing materials, ternary hydroxychloroacetic acid resin and binary hydroxychloroacetic acid resin. Table 2 shows that Examples 1-5, utilizing a combination of physical and chemical modification in this embodiment, optimize the block content and ratio of ternary hydroxychloroacetic acid resin and binary hydroxychloroacetic acid resin to obtain polishing pads with high elastic modulus, high removal rate, long cumulative service life, and virtually no defects on the wafer surface after polishing. Comparative Example 1 has less than 25% reinforcing material added, and Comparative Example 2 has a total reinforcing material added of 50%. The reinforcing material added in Comparative Examples 1 and 2 both exceed the preferred range of 25-45% in this application, and the molar ratio of ternary hydroxychloroacetic acid resin to binary hydroxychloroacetic acid resin exceeds the preferred 0.5-1.5:1 in this embodiment, resulting in poor overall performance in terms of elastic modulus and defect quantity. Comparative Examples 3 and 4 use single-component reinforcing agents. Compared to Comparative Example 5 without reinforcing agents, the improvement in mechanical properties is not significant, and a large number of serious defects exist, failing to meet the requirements of the fine polishing process.

[0093] Table 3. Raw materials and proportions of polishing pads in Examples 6-14 and Comparative Examples 6-8

[0094]

[0095] The ternary hydroxyl chloride resin, binary hydroxyl chloride resin, and preparation methods used in Examples 6-14 and Comparative Examples 6-7 are the same as in Example 1. The material ratios in Comparative Example 8 are the same as in Example 1, except that the ratio of chain extender to solvent is 1:15 and the ratio of reinforcing material to solvent is 1:5, as shown in Table 3.

[0096] Table 4 Evaluation results of polishing pads in Examples 6-12 and Comparative Examples 6-9

[0097]

[0098] As shown in Tables 3 and 4, Examples 6-9 adjusted the specific substances of the first isocyanate, the second isocyanate, the polyether polyol, and the chain extender. Comparing Examples 1 and 6 with Comparative Example 6, it can be seen that when the first and second isocyanates are the same, the elastic modulus, removal rate, and cumulative service life are all worse than polishing pads with different types of isocyanates, and the number of defects on the wafer surface after polishing is also significantly increased. Comparative Examples 7-8 used conventional MDA and ethylene glycol as chain extenders, but the molecular weight strength was insufficient, resulting in poor mechanical properties. Comparative Example 9 had the same material types and proportions as Example 1, except that the ratio of the chain extender and reinforcing material to the solvent in the preparation method was not optimal, leading to a lower elastic modulus and shorter cumulative service life in the final product.

[0099] It should be noted that, based on the explanations and descriptions in the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some equivalent modifications and alterations to the present invention should also be within the scope of protection of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the invention.

Claims

1. A polishing pad, comprising a polishing layer, characterized in that, The polishing layer raw material includes a first isocyanate, a second isocyanate different from the first isocyanate, a polyether polyol, a chain extender, and a reinforcing material; the chain extender is hydrazine hydrate; the reinforcing material is a combination of ternary hydroxyl vinyl acetate resin and binary vinyl acetate resin; the mass fraction of the reinforcing material is 25~45wt%; the elastic modulus of the polishing pad is 50~100 MPa.

2. The polishing pad according to claim 1, characterized in that, The molar ratio of the ternary hydroxyl chloroacetic acid resin to the binary chloroacetic acid resin is 0.5~1.5:1, preferably 1:

1.

3. The polishing pad according to claim 1, characterized in that, The proportions of each repeating unit in the ternary hydroxyl chloride-vinyl acetate resin are: vinyl chloride 75-95%, vinyl acetate 2-15%, and vinyl alcohol 3-15%; preferably: vinyl chloride 80-93%, vinyl acetate 3-10%, and vinyl alcohol 5-10%.

4. The polishing pad according to claim 1, characterized in that, The proportion of each repeating unit in the binary vinyl chloride-vinyl acetate resin is 75-95% vinyl chloride and 5-25% vinyl acetate; preferably, it is 80-90% vinyl chloride and 10-20% vinyl acetate.

5. The polishing pad according to claim 1, characterized in that, The first isocyanate and the second isocyanate are selected from toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; preferably, the first isocyanate is diphenylmethane diisocyanate and the second isocyanate is toluene diisocyanate.

6. The polishing pad according to claim 1, characterized in that, The polyether polyol is selected from at least one of polybutanediol, polypropylene glycol, and polyethylene glycol.

7. The polishing pad according to claim 1, characterized in that, The isocyanate index R = 1.01~1.03; the chain extender accounts for 22~28% of the molar percentage of the first isocyanate, the second isocyanate, the polyether polyol and the chain extender.

8. A method for preparing a polishing pad, characterized in that, Includes the following steps: S1. Prepolymerization: Polyether polyol reacts with the first isocyanate at 90 °C for 3 h. After the reaction is completed, the temperature is lowered to 60 °C, the second isocyanate is added, and the reaction continues for 2 h. Then, the solvent N,N-dimethylformamide is added, and the system is diluted to a prepolymer solution with a solid content of 25~35%. S2. Chain extension: Cool the prepolymer solution to room temperature, slowly add the chain extender solution to carry out the chain extension reaction; S3. Reinforcement: When the molecular weight of the detection system increases to between 80,000 and 100,000, add a reinforcing material solution, surfactant, etc., and stir evenly to obtain a polishing layer mixed slurry. S4. Molding: The polishing layer mixture is coated onto a non-woven fabric substrate, immersed in a coagulation liquid, and after coagulation, it is washed with water, sanded, embossed, and bonded with adhesive backing to obtain the polishing pad as described in any one of claims 1 to 7.

9. The method for preparing the polishing pad according to claim 8, characterized in that, The solvent in the chain extender solution is N,N-dimethylformamide, and the mass ratio of chain extender to solvent is 1:10; the solvent in the reinforcing material solution is N,N-dimethylformamide, and the mass ratio of reinforcing material to solvent is 1:3; the main components of the coagulation liquid include at least one of water, ethanol, methanol, and isopropanol.

10. A method for manufacturing a semiconductor device, characterized in that, The process includes a step of finely polishing the surface of a semiconductor wafer using the polishing pad described in any one of claims 1 to 7.

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