Chemical mechanical polishing soft pad and method of making same

Abstract

The present application relates to a kind of chemical mechanical polishing soft pad, including polishing layer, it is characterized in that, the polishing layer is obtained by the reaction of hydroxyl-terminated prepolymer, diphenyl methane diisocyanate and chain extender;The raw material of the prepolymer includes polyether polyol;The polyether polyol contains fluorine polyether polyol;After the film is formed by the re-dissolution of the polishing layer, the water drop contact angle of thin film is 83~120 °;The cell shape of the polishing layer is tear drop shape, and cell diameter is 30~80 μm.The chemical mechanical polishing soft pad provided by the present application is suitable for the fine polishing of Cu removal in semiconductor process copper damascene process, can improve the utilization rate of polishing liquid, improve removal rate, reduce scratch or depression and other defects, improve the uniformity of wafer after polishing, and also can prolong the service life of polishing pad.

Description

Technical Field

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

[0002] Chemical mechanical planarization (CMP) is currently the only ultra-precision machining method capable of achieving global planarization, and it is widely used in high-end manufacturing fields such as integrated circuit manufacturing. As one of the three core elements of a CMP system, the polishing pad (usually made of polyurethane) primarily functions to transfer the polishing slurry, maintain mechanical load, and remove wear debris. However, most commercially available polishing pads are intrinsically hydrophilic or have undergone hydrophilic treatment. This hydrophilic property presents a series of inherent technical bottlenecks when working synergistically with water-based polishing slurries:

[0003] First, the surface of the hydrophilic polishing pad has a strong wetting and spreading ability for water-based polishing fluids, resulting in the formation of an extremely thin liquid film on the pad surface. Although this thin liquid film appears to cover the surface evenly, it actually reduces the hydrodynamic pressure, causing a large amount of abrasive to be "floated" and unable to effectively embed into the pad surface to participate in cutting. This creates an unnecessary fluid lubrication layer, thereby weakening the mechanical grinding effect and reducing the material removal rate.

[0004] Secondly, the polishing slurry is prone to rapid loss along the grooves of the pad to the waste outlet on hydrophilic surfaces, resulting in low effective utilization of the expensive polishing slurry and increasing production costs. This problem is particularly prominent when processing high-hardness materials (such as silicon carbide), which requires a large amount of high-concentration slurry.

[0005] Furthermore, hydrophilic polishing pads easily adsorb hydrophilic impurities such as silicon dust, oxides, and reaction byproducts generated during the polishing process. These debris can clog the microporous structure of the polishing pad surface, reducing its ability to hold abrasive and transport polishing fluid. This not only shortens the lifespan of the polishing pad but also exacerbates scratches on the wafer surface and worsens the uniformity of the wafer after polishing. Summary of the Invention

[0006] The purpose of this invention is to provide a chemical mechanical polishing pad with certain hydrophobicity, suitable for fine polishing processes, to increase the utilization rate of polishing fluid, improve the grinding removal rate, reduce surface scratch defects, and extend the service life of the polishing pad.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, this application provides a chemical mechanical polishing pad, comprising a polishing layer, characterized in that the polishing layer is obtained by reacting a hydroxyl-terminated prepolymer, diphenylmethane diisocyanate, and a chain extender; the prepolymer raw material comprises a polyether polyol; after the polishing layer is reconstituted into a film, the film water droplet contact angle is 83~120°; the pore shape of the polishing layer is teardrop-shaped, and the pore diameter is 30~80 μm.

[0009] In some possible implementations, the polyether polyol comprises a fluorinated polyether polyol; the fluorine atom content in the polishing layer is 0-8 wt%.

[0010] In some possible embodiments, the fluorinated polyether polyol comprises repeating units -(OCF2CFR) f )-, where R f For -F or -CF3.

[0011] In some possible implementations, the fluorine atom content in the fluorinated polyether polyol is 40-70 wt%.

[0012] In some possible embodiments, the number-average molecular weight of the fluorinated polyether polyol is 500 to 5000 g / mol.

[0013] In some possible implementations, the fluorinated polyether polyol structure includes:

[0014] ;

[0015] ;

[0016] ;

[0017] ;

[0018] .

[0019] In some possible implementations, the non-fluorinated polyether polyol includes at least one of polypropylene oxide, polytetrahydrofuran, polyethylene oxide, and polypropylene oxide-ethylene oxide copolymer.

[0020] In some possible embodiments, the chain extender includes at least one of ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, purified water, 1,6-hexanediol, glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol, and diethylaminoethanol.

[0021] In some possible embodiments, the prepolymer raw material further includes a polyester polyol, which is obtained by copolymerizing adipic acid with at least one monomer selected from ethylene glycol, 1,4-butanediol, and hexanediol.

[0022] Secondly, this application provides a method for preparing a chemical mechanical polishing pad as provided in the first aspect of this application, comprising the following steps:

[0023] S1. Prepolymer preparation: Diisocyanate reacts with polyester polyol and polyether polyol under the action of a catalyst to generate hydroxyl-terminated prepolymer;

[0024] S2. Chain extension reaction: Add the above prepolymer, diisocyanate and chain extender to the solvent and react at 65-110°C to extend the chain;

[0025] S3. Preparation of coating solution: Add surfactant and appropriate amount of solvent to the system, and control the resin mass fraction to be 20~40wt%;

[0026] S4. Foaming molding: The resin solution is applied to the substrate and immersed in a coagulation liquid with water as the main component. After the foam cells are set, the substrate is washed with water and dried.

[0027] In some possible embodiments, the catalyst comprises one or more combinations of 1,4-diazabicyclo[2.2.2]octane, N,N-dimethylcyclohexylamine, benzyl dimethylamine, dibutyltin dilaurate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

[0028] In some possible implementations, the solvent includes one or more combinations of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and dimethyl sulfoxide.

[0029] Beneficial effects:

[0030] A wet film-forming method was used to prepare a polishing layer with teardrop-shaped pores. Fluorinated polyether polyol was added to give the polishing layer a certain degree of hydrophobicity. This method was applied to the fine polishing step of Cu removal in the copper damask process of semiconductor manufacturing. It can adjust the pore size of the polishing layer, improve the removal rate, reduce defects such as scratches or dents, improve the uniformity of the wafer after polishing, and extend the service life of the polishing pad. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is an SEM image of the cross-section of the polished layer in Example 1. Detailed Implementation

[0033] 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.

[0034] It should be noted that the following embodiments are examples of this application and are used only to illustrate this application, and are not intended to limit this application. Other combinations and various modifications within the scope of this application are possible without departing from the spirit or scope of this application.

[0035] The chemical mechanical polishing pad and its preparation method provided in this application are described in detail below.

[0036] <Chemical Mechanical Polishing Pad>

[0037] This embodiment provides a chemical mechanical polishing pad, including a polishing layer, the polishing layer comprising:

[0038] A hydroxyl-terminated prepolymer obtained by reacting diphenylmethane diisocyanate with polyester polyol and polyether polyol, wherein the polyether polyol includes non-fluorinated polyether polyol and / or fluorinated polyether polyol.

[0039] In this embodiment, the polishing layer is prepared by a wet film-forming method. The polyurethane solution film is immersed in a poor solvent to precipitate the resin. At the same time, the solvent in the original resin solution dissolves from one side of the film into the poor solvent, so that the bubble shape in the film is teardrop-shaped.

[0040] In this embodiment, the teardrop-shaped bubble diameter is 30~80 μm. If the diameter is too small, there will be too little polishing fluid loaded in the bubble, which is not conducive to the chemical mechanical polishing of the wafer surface. If the diameter is too large, the porosity of the polishing layer will be too high, which will affect the mechanical properties of the polishing layer and reduce the removal rate and service life.

[0041] Hydroxyl-terminated prepolymers

[0042] In this embodiment, the hydroxyl-terminated prepolymer is obtained by reacting diphenylmethane diisocyanate with polyester polyol and polyether polyol. To obtain a polishing pad with the desired polishing performance, the isocyanate index in the prepolymer, i.e., the molar ratio of isocyanate to hydroxyl groups in the system, is controlled. The isocyanate index R is controlled to be between 0.77 and 0.94. When R is greater than 0.94, it is difficult to generate hydroxyl-terminated polyurethane prepolymer. When R is less than 0.77, the content of isocyanate hard segments is too low, which affects the mechanical properties of the polishing layer.

[0043] In this embodiment, the diisocyanate is diphenylmethane-4,4'-diisocyanate, which contains two rigid benzene rings in its molecular structure, which can enhance the mechanical properties of the polishing layer and improve the removal rate.

[0044] In this embodiment, the polyester polyol is obtained by copolymerizing adipic acid with at least one of ethylene glycol, 1,4-butanediol, and hexanediol. Examples of such polyols include: polyethylene adipate, polybutylene adipate, polyethylene adipate-butylene adipate, polyethylene glycol-adipic acid-butylene adipate, polyethylene glycol-adipic acid-hexanediol, polybutylene glycol-adipic acid-hexanediol, and polyethylene glycol-butylene glycol-adipic acid-hexanediol.

[0045] Non-fluorinated polyether polyols

[0046] In this embodiment, the non-fluorinated polyether polyol includes one or more combinations of polypropylene oxide, polytetrahydrofuran, polyethylene oxide, and polypropylene oxide-ethylene oxide copolymer.

[0047] In this embodiment, a polyether polyol with an average functionality of 2 to 3 is selected. By adjusting the average functionality of the polyether polyol, the degree of crosslinking of the product is controlled, thereby obtaining polishing pad substrates with different hardness and elasticity. Specifically, when a polyether polyol with an average functionality greater than 3 is used, the resulting polyurethane substrate is too hard, easily causing scratches on the workpiece and failing to meet the requirements for fine polishing of the wafer surface; when a polyether polyol with an average functionality less than 2 is used, the resulting polyurethane substrate is too soft, making it difficult to meet the planar uniformity requirements of the workpiece to be polished.

[0048] Fluorinated polyether polyols

[0049] In this embodiment, the fluorinated polyether polyol includes at least the repeating unit -(OCF2CFR) f )-, where R fThe polyol is -F or -CF3. In this embodiment, a highly hydrophobic fluorinated polyether polyol is added, making the water-based polishing slurry less likely to be absorbed by the polishing layer or spread into a very thin liquid film. Instead, it tends to form droplets or a thicker liquid layer, allowing more abrasive particles to directly contact and act on the wafer surface, improving the utilization rate of the polishing slurry. Furthermore, the hydrophobic polishing layer is less likely to adsorb hydrophilic contaminants such as debris and reaction products generated during polishing, reducing defects such as scratches and pits. Simultaneously, it makes it easier for the polishing layer to maintain its microstructure and surface porosity, improving the polishing uniformity of the wafer throughout the year and extending the lifespan of the polishing pad. The fluorinated polyether polyol prepared from perfluoroethylene or perfluoropropylene monomers has F atoms distributed in the polymer backbone, allowing it to be directly polymerized and block-into the polyurethane resin molecular chain; and includes -(OCF2CFR) f The fluorinated polyether polyols of repeating units contain 40~70 wt% F atoms, which can achieve better hydrophobic properties of polyurethane resin with a small amount of addition.

[0050] In this embodiment, the fluorine atom content in the polishing layer is 0.2~8 wt%. The pore size is negatively correlated with the fluorine atom content; the higher the fluorine atom content, the stronger the resin's hydrophobicity, and the faster its precipitation and curing rate in the water-based coagulation solution. This results in smaller pore sizes formed by solvent phase transfer in the resin layer. When the fluorine atom content is below 0.2 wt%, the hydrophobicity it provides is insufficient, and the beneficial effects of the enhanced hydrophobicity are limited. When the fluorine atom content is above 8 wt%, the resin becomes too hydrophobic, resulting in excessively fast precipitation and curing rates in the coagulation solution. This leads to excessively small pore sizes, significantly reducing the carrying capacity of the polishing solution and hindering the chemical mechanical planarization of the polished surface.

[0051] In this embodiment, the structural formula of the fluorinated polyether polyol includes, but is not limited to:

[0052] Structure a:

[0053] ;

[0054] Structure b:

[0055] ;

[0056] Structure c:

[0057] ;

[0058] Structure d:

[0059] ;

[0060] Structure e:

[0061] .

[0062] Fluorinated polyether polyols have a number-average molecular weight of 500–5000 g / mol. If the molecular weight is too low, the elasticity is insufficient, the buffering effect is poor, the polishing layer is too hard, and it easily scratches the wafer surface. Furthermore, due to its increased susceptibility to wear, it is not the preferred choice from the perspective of polishing pad lifespan. On the other hand, if the molecular weight is too high, the polyurethane resin becomes too soft, with too low hardness and elastic modulus, resulting in a lower polishing layer removal rate.

[0063] Chain extender

[0064] In this embodiment, the chain extender includes, but is not limited to, one or more combinations of ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, purified water, 1,6-hexanediol, glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol, and diethylaminoethanol.

[0065] Preferably, the chain extender includes, but is not limited to, one or more combinations of ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, and pure water.

[0066] In this invention, the chain extender makes the polyurethane resin molecular structure more uniform and the molecular weight higher, which helps to improve the service life of the polishing pad and suppress uneven polishing properties.

[0067] Water droplet contact angle

[0068] In this embodiment, the polishing layer of the chemical mechanical polishing pad has a certain degree of hydrophobicity. During the polishing process, it is not easy to adsorb hydrophilic contaminants such as debris and reaction products, reducing defects such as scratches or pits. In addition, it makes it easier for the polishing layer to maintain its microstructure and surface pores, improves the uniformity of in-plane polishing of the wafer, and extends the service life of the polishing pad.

[0069] In this embodiment, hydrophobicity is evaluated using the water droplet contact angle. A sample of the polished layer is taken from the surface of the molded chemical mechanical polishing pad. The polished layer sample is dissolved, coated into a film, and the water droplet contact angle of the reconstituted film is tested using the seated drop method. In this embodiment, the water droplet contact angle of the polished layer of the chemical mechanical polishing pad is between 83° and 120°.

[0070] <Preparation Method of Chemical Mechanical Polishing Pad>

[0071] This embodiment also relates to a method for preparing a chemical mechanical polishing pad, including the following steps:

[0072] S1. Preparation of prepolymer: Diisocyanate reacts with polyester polyol and polyether polyol in the presence of a catalyst to generate hydroxyl-terminated prepolymer. The reaction temperature is 65-110℃, and the isocyanate index R is controlled to be 0.77-0.94.

[0073] S2. Chain extension reaction: Add the above prepolymer, diisocyanate, and chain extender to the solvent and react at 65-110℃ to extend the chain;

[0074] S3. Preparation of coating solution: After chain extension, add 0.5-10 wt% of surfactant relative to the mass of polyurethane resin and an appropriate amount of solvent to the system to adjust the resin mass fraction to 20-40 wt%.

[0075] S4. Foaming and molding: The above polyurethane resin solution is applied to a waterproof substrate, immersed in a coagulation liquid with water as the main component, and washed and dried after the foam cells are set.

[0076] catalyst

[0077] In this embodiment, the catalyst includes, but is not limited to, one or more combinations of tertiary amine catalysts or organometallic catalysts. The tertiary amine catalysts include, but are not limited to, one or more combinations of 1,4-diazabicyclo[2.2.2]octane, N,N-dimethylcyclohexylamine, benzyl dimethylamine, triethylenediamine, and tetramethylbutanediamine. The organometallic catalysts include, but are not limited to, one or more combinations of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

[0078] In this embodiment, the catalyst selectively accelerates the polymerization reaction.

[0079] solvent

[0080] In this embodiment, the solvent is selected from polar solvents that are miscible with water, including but not limited to one or more combinations of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and dimethyl sulfoxide.

[0081] In this embodiment, the solvent dissolves the polyurethane resin and, during impregnation in the coagulation bath, becomes miscible with the water in the coagulation bath, causing the polyurethane resin to undergo phase transfer and precipitate, forming teardrop-shaped bubbles.

[0082] surfactants

[0083] This embodiment may also include surfactants, which include nonionic surfactants or anionic surfactants; nonionic surfactants include, but are not limited to, one or more combinations of polyoxyethylene ethers, fatty acid glycerides, and alkanolamides; anionic surfactants include, but are not limited to, one or more combinations of carboxylates, sulfonates, sulfates, and phosphates.

[0084] Surfactants promote the dissolution of fluorinated polyether resins in solvents and regulate the pore size and porosity of the bubbles formed when the resin solution precipitates in the coagulation bath.

[0085] Example

[0086] 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 considered as specific limitations thereof.

[0087] In this embodiment, fluorinated polyether polyol structures a and b were purchased from SOLVAY under the FLUOROLINK brand, and structures d, e, and f were purchased from CHINLOX 202H under the Functional PFPE brand; other raw materials were all from commercially available bulk industrial products, and manufacturers included BASF, Wanhua Chemical, Asahikawa Chemical, and Huafeng.

[0088] Explanation of reference numerals in the embodiments:

[0089] MDI: Diphenylmethane diisocyanate

[0090] DMA: N,N-dimethylacetamide

[0091] TDI: Toluene diisocyanate

[0092] DMF: N,N-dimethylformamide

[0093] Example 1

[0094] S1. Preparation of prepolymer: MDI, polytetrahydrofuran, fluorinated polyether polyol (structure a, Mn = 3000, 6 wt% of polyurethane resin mass), and polyhexamethylene adipate were reacted with dibutyltin dilaurate as a catalyst to generate a hydroxyl-terminated prepolymer. The reaction temperature was 85 °C, and the isocyanate index R was controlled to be 0.87.

[0095] S2. Chain extension reaction: The prepolymer, MDI and chain extender (ethylene glycol) are added to the solvent DMA; the chain extension reaction is carried out at 87°C.

[0096] S3. Preparation of coating solution: After chain extension, 3 wt% of surfactant (sodium dodecylbenzenesulfonate) and an appropriate amount of solvent DMA were added to the system to adjust the resin mass fraction to 32 wt%.

[0097] S4. Foaming molding: The above polyurethane resin solution is coated onto a waterproof substrate (PET), immersed in a coagulation solution with water as the main component, and washed and dried after the foam cells are set.

[0098] Examples 2-4

[0099] The preparation methods of Examples 2-4 are the same as those of Example 1, except that the structure and content of the fluorinated polyether polyol are different, as shown in Table 1.

[0100] Example 5

[0101] The preparation method of Example 5 is the same as that of Example 2, except that the structure of the fluorinated polyether polyol is f:

[0102] .

[0103] Example 6

[0104] The preparation method of Example 6 is the same as that of Example 2, except that no fluorinated polyether polyol is added.

[0105] Example 7

[0106] The preparation method of Example 7 is the same as that of Example 2, except that the structure of the fluorinated polyether polyol is a':

[0107] .

[0108] Example 8

[0109] The preparation method of Example 8 is the same as that of Example 2, except that the amount of fluorinated polyether polyol added is 0.3 wt%.

[0110] Comparative Example 1

[0111] The preparation method of Comparative Example 1 is the same as that of Example 2, except that TDI is used instead of MDI.

[0112] Comparative Example 2

[0113] The preparation method of Comparative Example 2 is the same as that of Example 2, except that the amount of fluorinated polyether polyol added is 18wt%.

[0114] Comparative Example 3

[0115] The preparation method of the polyurethane resin in Comparative Example 3 is the same as that in Example 2, except that microspheres (Expancel 551DE40d42) are added to foam the resin, which is then poured into a mold, heated to 110 °C, and cured.

[0116] Table 1

[0117]

[0118] The performance parameters of this embodiment and the comparative example were measured using the following methods:

[0119] Bubble shape

[0120] The cross-section of a chemical mechanical polishing pad was photographed using a scanning electron microscope to observe the shape of the pores.

[0121] Foam pore size

[0122] The surface of the chemical mechanical polishing pad was photographed using a scanning electron microscope. Thirty cells were randomly identified using the Image Pro Plus program, and their average value was calculated and recorded as the cell diameter of the sample.

[0123] Fluorine atomic content test

[0124] X-ray fluorescence spectroscopy (HITACHI EA1280) was used to sample three different locations on the polishing layer of the same chemical mechanical polishing pad to determine the fluorine atom content. The average value of the three test values ​​was recorded as the fluorine atom content in the polishing layer of the chemical mechanical polishing pad.

[0125] Water droplet contact angle evaluation

[0126] A small portion of the molded chemical mechanical polishing pad was reconstituted with DMF solvent. The reconstituted solution was then spin-coated onto a silicon wafer to form a film. Using the seated drop method with a fixed volume of water, a 2.0 μL water droplet was slowly pushed out and suspended on the syringe needle. The knob was then adjusted to raise the sample stage. When the sample surface touched the droplet, the knob was adjusted to lower the sample stage. The contact angle of the water droplet on the sample surface was recorded. Ten consecutive tests were performed, and the average value was recorded as the water droplet contact angle of the reconstituted film of the chemical mechanical polishing pad.

[0127] Removal rate evaluation

[0128] Specific polishing conditions: Polishing of copper (Cu) using an F-REX300X polishing machine with a downforce of 1.5 psi, a polishing disc / polishing head speed of 93 / 87 rpm, a polishing slurry of D3000 with a flow rate of 250 mL / min, and a polishing time of 1 min.

[0129] Defect evaluation

[0130] Defects such as scratches or pits after copper wafer polishing are inspected using the Surfscan® SP7 system, with a defect size of 60 nm.

[0131] Intra-wafer uniformity

[0132] The polishing rate at 49 points on the surface of the copper wafer was statistically analyzed, and the uniformity within the wafer after polishing was evaluated by the following formula: Uniformity within the wafer % = [(Maximum polishing rate - Minimum polishing rate) / (Average polishing rate × 2)] × 100.

[0133] Service life evaluation

[0134] The examples and comparative examples were subjected to wafer planar polishing tests, and their maximum service life was recorded.

[0135] The performance evaluation results of the examples and comparative examples are shown in Table 2.

[0136] Table 2

[0137]

[0138] 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 chemical mechanical polishing pad, comprising a polishing layer, characterized in that, The polishing layer is obtained by reacting a hydroxyl-terminated prepolymer, diphenylmethane diisocyanate, and a chain extender; the prepolymer raw material includes polyether polyol; after the polishing layer is reconstituted into a film, the water droplet contact angle of the film is 83~120°; the pore shape of the polishing layer is teardrop-shaped, and the pore diameter is 30~80 μm.

2. The chemical mechanical polishing pad according to claim 1, wherein the polyether polyol comprises a fluorinated polyether polyol; and the fluorine atom content in the polishing layer is 0~8wt%.

3. The chemical mechanical polishing pad according to claim 1, wherein the fluorinated polyether polyol comprises repeating units -(OCF2CFR) f )-,in, R f For -F or -CF3.

4. The chemical mechanical polishing pad according to claim 1, characterized in that, The fluorine atom content in the fluorinated polyether polyol is 40~70 wt%.

5. The chemical mechanical polishing pad according to claim 1, characterized in that, The number-average molecular weight of the fluorinated polyether polyol is 500–5000 g / mol.

6. The chemical mechanical polishing pad according to claim 1, characterized in that, The fluorinated polyether polyol has the following structural formula: ； ； ； ； 。 7. The chemical mechanical polishing pad according to claim 1, characterized in that, The non-fluorinated polyether polyol includes at least one of polypropylene oxide, polytetrahydrofuran, polyethylene oxide, and polypropylene oxide-ethylene oxide copolymer.

8. The chemical mechanical polishing pad according to claim 1, characterized in that, The chain extender includes at least one of ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, purified water, 1,6-hexanediol, glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol, and diethylaminoethanol.

9. The chemical mechanical polishing pad according to claim 1, characterized in that, The prepolymer raw material also includes polyester polyol, which is obtained by copolymerizing adipic acid with at least one monomer selected from ethylene glycol, 1,4-butanediol and hexanediol.

10. A method for preparing a chemical mechanical polishing pad as described in any one of claims 1 to 10, characterized in that, Includes the following steps: S1. Prepolymer preparation: Diisocyanate reacts with polyester polyol and polyether polyol under the action of a catalyst to generate hydroxyl-terminated prepolymer; S2. Chain extension reaction: Add the above prepolymer, diisocyanate and chain extender to the solvent and react at 65-110 °C to extend the chain; S3. Preparation of coating solution: Add surfactant and appropriate amount of solvent to the system, and control the resin mass fraction to be 20~40wt%; S4. Foaming molding: The resin solution is applied to the substrate and immersed in a coagulation liquid with water as the main component. After the foam cells are set, the substrate is washed with water and dried.

11. The method for preparing a chemical mechanical polishing pad according to claim 10, characterized in that, The catalyst comprises one or more combinations of 1,4-diazabicyclo[2.2.2]octane, N,N-dimethylcyclohexylamine, benzyl dimethylamine, dibutyltin dilaurate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

12. The method for preparing a chemical mechanical polishing pad according to claim 10, characterized in that, The solvent includes one or more combinations of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and dimethyl sulfoxide.

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