Polishing pad applied to rough polishing of diamond substrate and preparation method of polishing pad

Abstract

The invention relates to a polishing pad applied to rough polishing of a diamond substrate and a preparation method of the polishing pad. The preparation method comprises the following steps: S1, mixing the chain extension cross-linking agent, the high-strength polyol a, the surfactant, the catalyst, the dispersing agent and the filler to obtain a composition A; s2, carrying out prepolymerization on isocyanate and high-strength polyol b to obtain a composition B; s3, uniformly mixing the composition A and the composition B through stirring; s4, the mixture is poured into a mold with temperature control, forming and preliminary curing are carried out, and a uniform micropore structure is generated; and S5, slicing operation is conducted on the formed body after post-curing, and the polishing pad with the uniform thickness is obtained. The polyurethane two-component system is prepared by adopting a two-step method, so that the physical strength and the wear resistance of the prepared polishing pad are improved, the service life is prolonged, the replacement frequency is reduced, and the production efficiency is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polishing pads, and in particular to a method for preparing a polishing pad used for rough polishing of diamond substrates. Background Art

[0002] Diamond substrates are a crucial material in the manufacturing of semiconductor and optoelectronic devices due to their excellent thermal conductivity, chemical stability, and high hardness. However, the processing and polishing of diamond substrates still present numerous production challenges, particularly during the rough polishing stage, which requires polishing pads to possess high strength, wear resistance, and excellent cutting performance. Conventional polishing pads often fail to meet these stringent requirements, necessitating the development of a high-performance polishing pad material suitable for rough polishing of diamond substrates.

[0003] Existing polishing pads typically use materials such as polyurethane or silicone, which can wear quickly and have difficulty controlling surface roughness during polishing. This not only affects the processing efficiency of diamond substrates but can also negatively impact subsequent precision polishing and device performance.

[0004] Therefore, the existing technology needs to be improved. Summary of the Invention

[0005] In the prior art, existing polishing pads may suffer from problems such as rapid wear and difficulty in controlling surface roughness during the polishing process. Therefore, the present invention provides a polishing pad for rough polishing of diamond substrates and a preparation method thereof to solve the above problems.

[0006] In a first aspect, the present invention provides a method for preparing a polishing pad for rough polishing of a diamond substrate, comprising the following specific steps: S1, mixing a chain extender, a high-strength polyol a, a surfactant, a catalyst, a dispersant, and a filler to obtain a composition A; S2, prepolymerizing isocyanate and high-strength polyol b to obtain composition B; S3, uniformly mixing composition A and composition B by stirring; S4, pouring the mixture into a mold with temperature control, performing molding and preliminary curing, and generating a uniform microporous structure; S5. After post-curing, the formed body is sliced ​​to obtain a polishing pad with uniform thickness.

[0007] In one implementation, in S1, the chain extender cross-linking agent is a polyether polyol or an epoxy resin, and the amount used is 5%-15% of the total weight of the composition A.

[0008] In one implementation, in S1, the molecular weight of the high-strength polyol a is 2000-4000, and its usage in composition A is 30%-50%.

[0009] In one implementation, in S1, the surfactant is an anionic surfactant, and its mass fraction is 2%-8% of the total mass of composition A.

[0010] In one implementation, in S1, the catalyst is an amine catalyst, and its usage amount is 0.1%-2% of the total weight of composition A.

[0011] In one implementation, in S1, the dispersant is a polymer dispersant, and its amount in composition A is 1%-5%.

[0012] In one implementation, in S2, the high-strength polyol b is a polyether polyol or a polyester polyol.

[0013] In one implementation, in S3, the stirring rate is 300-600 rpm, and the temperature is controlled between 20-30°C.

[0014] In one implementation, in S4, the temperature of the preliminary curing after forming is 50-70° C., and the curing time of the preliminary curing is 2-6 hours.

[0015] In a second aspect, the present invention further provides a polishing pad for rough polishing of diamond substrates, which is prepared by the above-mentioned method for preparing a polishing pad for rough polishing of diamond substrates.

[0016] Beneficial effects: The present invention uses a homemade high-strength polyol material and an appropriate amount of chain extender and cross-linker to prepare a polyurethane two-component system in a two-step method, thereby improving the physical strength and wear resistance of the polishing pad, extending its service life, reducing the replacement frequency, and thus improving production efficiency; at the same time, by precisely controlling the molding and preliminary aging processes, a uniform microporous structure is obtained, so that the polishing pad can effectively remove particles generated by polishing during use, improve polishing uniformity, and thus achieve higher surface quality during the rough polishing process of the diamond substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flowchart of the steps of preparing a polishing pad for rough polishing of a diamond substrate.

[0018] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the descriptions of the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" described below mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0020] Specific reference Figure 1 , Figure 1 The present invention is a flowchart of the steps of preparing a polishing pad for rough polishing of a diamond substrate.

[0021] The present invention provides a method for preparing a polishing pad for rough polishing of a diamond substrate, which comprises the following specific steps: S1, mixing a chain extender, a high-strength polyol a, a surfactant, a catalyst, a dispersant, and a filler to obtain a composition A; S2, prepolymerizing isocyanate and high-strength polyol b to obtain composition B; S3, uniformly mixing composition A and composition B by stirring; S4, pouring the mixture into a mold with temperature control, performing molding and preliminary curing, and generating a uniform microporous structure; S5. After post-curing, the formed body is sliced ​​to obtain a polishing pad with uniform thickness.

[0022] Specifically, in S1, the chain extender crosslinker is a polyether polyol or epoxy resin, and its usage amount is 5%-15% of the total weight of Composition A. The high-strength polyol a has a molecular weight of 2000-4000, and its usage amount in Composition A is 30%-50%. High-strength polyol a is a polyether- or polyester-based polymer material with a high molecular weight (2000-4000) and good chemical stability and mechanical strength. High-strength polyol a comprises either a polytetrafluoroethylene (PTFE)-based polyol or an amino polyether polyol. The surfactant is an anionic surfactant, and its mass fraction is 2%-8% of the total mass of Composition A. The catalyst is an amine catalyst, preferably triethanolamine, and its usage amount is 0.1%-2% of the total weight of Composition A. The dispersant is a polymer dispersant, preferably a polyvinyl alcohol dispersant, and its usage amount in Composition A is 1%-5%. The filler is calcium silicate.

[0023] In S2, the high-strength polyol b is a polyether polyol or a polyester polyol, wherein the polyether polyol is preferably a polyethylene glycol or polypropylene glycol-based polyol, which can be combined with isocyanate for prepolymerization.

[0024] In S3 , the stirring rate is 300-600 rpm, and the temperature is controlled between 20-30° C. The diameter of the generated microporous structure is between 1 and 50 μm.

[0025] In S4, the temperature of the preliminary curing after forming is 50-70° C., and the time of the preliminary curing is 2-6 hours.

[0026] The following are examples of the present invention to better understand its specific applications.

[0027] Example 1 Materials preparation: Polyether polyol: Select polyether polyol with a molecular weight of 3000 to ensure it has good mechanical properties and flexibility, and the usage is 90g.

[0028] Surfactant: An anionic surfactant is selected to reduce interfacial tension. In this embodiment, sodium dodecylbenzenesulfonate is used in an amount of 6 g.

[0029] Catalyst: Triethanolamine was used as a catalyst in an amount of 1 g to accelerate the reaction rate.

[0030] Filler: Silicon monoxide is used as a filler to improve the structural stability of the polishing pad, and the amount used is 50g.

[0031] Dispersant: Use polyvinyl alcohol dispersant, the usage amount is 3g.

[0032] Chain extender and cross-linker: 10g of epoxy resin was used as a chain extender and cross-linker to increase the cross-linking density of the polishing pad.

[0033] S1. According to the mass ratio of the above materials, polyether polyol, surfactant, catalyst, filler, dispersant and chain extender cross-linking agent are mixed in a blender in turn to ensure uniform dispersion. The stirring time is continuous for 15 minutes.

[0034] S2. Select a polyether polyol with a molecular weight of 3000 and an isocyanate in a 1:1 ratio. Prepolymerize 50g of isocyanate with the polyether polyol B in the working material. Set the heating temperature to 65°C and continue the reaction for 1 hour to ensure sufficient reaction.

[0035] S3. In a stirring device, mix compositions A and B at a speed of about 500 rpm, set the temperature control at 25° C., and mix for 10 minutes to ensure that the two are fully and evenly mixed.

[0036] S4. The uniformly mixed mixture is quickly poured into a mold with a temperature control system for molding. The mold temperature is set at 25°C and the initial curing time is 2 hours to ensure the formation of the microporous structure.

[0037] After the initial aging, transfer to a heating device for post-aging at 60°C for 5 hours to ensure complete cross-linking and enhance the mechanical properties of the material. After post-aging, cut the material into uniform polishing pads, with a thickness between 3-5mm, to ensure good flatness and moderate flexibility during use.

[0038] Example 2 The difference from Example 1 is that the present embodiment includes the following raw materials by weight: Polyether polyol (molecular weight 2500): 85g; Sodium dodecylbenzenesulfonate: 5g; Triethanolamine: 1g; Silicon monoxide: 55g; Polyvinyl alcohol dispersant: 4g; Epoxy resin: 10g; Isocyanate: 55g.

[0039] The preparation process in this embodiment is the same as that in the embodiment, and will not be repeated here.

[0040] Example 3 The difference from Example 1 is that the present embodiment includes the following raw materials by weight: Polyester polyol (molecular weight 3500): 88g; Sodium dodecylbenzenesulfonate: 6g; Triethanolamine: 1g; Silicon monoxide: 52g; Polyvinyl alcohol dispersant: 3g; Polytetrafluoroethylene polyol (polymer): 10g; Isocyanate: 52g.

[0041] The preparation process in this embodiment is the same as that in the embodiment, and will not be repeated here.

[0042] Comparative Example 1 The difference from Example 1 is that this comparative example includes the following raw materials by weight: Polyether polyol (molecular weight 1000): 90g; Sodium dodecylbenzenesulfonate: 6g; Triethanolamine: 1g; Silicon monoxide: 50g; Dispersant: 3g; No chain extender cross-linker (not added); Isocyanate: 50g; Other process conditions are the same as in Example 1.

[0043] Comparative Example 2 The raw material formula in this comparative example is the same as that in Example 1, but step S5 is omitted and post-ripening is not performed.

[0044] The present invention conducted performance tests on the aforementioned embodiments and comparative examples. The tensile strength and tear strength were measured using an electronic universal material testing machine in accordance with GB / T 528-2009 Rubber, vulcanized or thermoplastic rubber — Determination of tensile stress-strain properties and GB / T 529-2008 Rubber, vulcanized or thermoplastic rubber — Determination of tear strength. The average pore size and pore size distribution standard deviation were measured on polishing pad cross-sections using a scanning electron microscope (SEM) coupled with image analysis software, with statistical results obtained across multiple viewing fields.

[0045] The performance test results are shown in Table 1.

[0046] Table 1. Performance test data of polishing pads prepared in various embodiments and comparative examples.

[0047] As can be seen from the above table, the polishing pads prepared in Examples 1-3 for rough polishing of diamond substrates all exhibited good mechanical properties and micropore uniformity, which were significantly better than those in the comparative example. In Comparative Example 1, no high-strength polymer polyol was used, resulting in insufficient crosslinking density, loose structure, and significantly reduced mechanical properties. In Comparative Example 2, no post-curing was performed, resulting in incomplete crosslinking of the polyurethane, unstable pores, large pore size, and wide distribution. The micropore structure was well controlled in the examples, with small and uniform pore size, which was conducive to the adsorption and distribution of the polishing liquid.

[0048] In this embodiment, a self-made high-strength polyol is introduced into component A and component B respectively through a two-step method, and participates in prepolymerization and chain extension cross-linking reactions respectively to form a polyurethane network with a high cross-linking density, which effectively improves the tensile strength, tear strength and resilience of the polishing pad, and meets the use requirements in high stress and high friction environments during the rough polishing of diamond substrates. During the prepolymerization and mixing process, the components react fully, and the reaction rate is coordinated with the foaming process, so that the reaction system produces a stable and continuous microporous structure. The uniform pore structure is conducive to maintaining the adsorption and distribution of the polishing liquid, and improving the polishing efficiency and consistency. The prepared polishing pad has good wear resistance and elastic recovery ability, and is suitable for the working conditions under high load and high speed operation in the rough polishing stage of diamond substrates, significantly reducing the generation of scratches and microcracks, and improving the final yield.

[0049] In summary, the present invention uses a homemade high-strength polyol material and an appropriate amount of chain extender and cross-linker to prepare a polyurethane two-component system in a two-step method, thereby improving the physical strength and wear resistance of the polishing pad, extending its service life, reducing the replacement frequency, and thus improving production efficiency; at the same time, by precisely controlling the molding and preliminary aging processes, a uniform microporous structure is obtained, so that the polishing pad can effectively remove particles generated by polishing during use, improve polishing uniformity, and thus achieve higher surface quality during the rough polishing process of the diamond substrate.

[0050] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a polishing pad for rough polishing of a diamond substrate, characterized in that: The specific steps include: S1, mixing a chain extender, a high-strength polyol a, a surfactant, a catalyst, a dispersant, and a filler to obtain a composition A; S2, prepolymerizing isocyanate and high-strength polyol b to obtain composition B; S3, uniformly mixing composition A and composition B by stirring; S4, pouring the mixture into a mold with temperature control, performing molding and preliminary curing, and generating a uniform microporous structure; S5. After post-curing, the formed body is sliced ​​to obtain a polishing pad with uniform thickness.

2. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S1, the chain extender cross-linking agent is polyether polyol or epoxy resin, and its usage amount is 5%-15% of the total weight of composition A.

3. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S1, the molecular weight of the high-strength polyol a is 2000-4000, and its usage in composition A is 30%-50%.

4. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S1, the surfactant is an anionic surfactant, and its mass fraction is 2%-8% of the total mass of composition A.

5. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S1, the catalyst is an amine catalyst, and its usage amount is 0.1%-2% of the total weight of composition A.

6. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S1, the dispersant is a polymer dispersant, and its amount in composition A is 1%-5%.

7. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S2, the high-strength polyol b is a polyether polyol or a polyester polyol.

8. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S3, the stirring rate is 300-600 rpm, and the temperature is controlled between 20-30°C.

9. The method for preparing a polishing pad for rough polishing of a diamond substrate according to claim 1, wherein: In S4, the temperature of the preliminary curing after forming is 50-70° C., and the time of the preliminary curing is 2-6 hours.

10. A polishing pad for rough polishing of a diamond substrate, characterized in that: The polishing pad is prepared by the method for preparing a polishing pad for rough polishing of a diamond substrate according to any one of claims 1 to 9.

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