Oil-based heat-sensitive active grinding fluid and microwave-assisted fixed abrasive grinding method

Abstract

The invention discloses an oil-based thermosensitive active grinding liquid and a microwave-assisted fixed abrasive grinding method. The oil-based thermosensitive active grinding liquid comprises the following components: 0.5% to 5% by mass of propylene glycol, 0.5% to 5% by mass of triethanolamine, 1% to 10% by mass of a thermosensitive oxidant, and the remainder is vegetable oil. Microwaves induce the thermal decomposition initiator in the thermosensitive active grinding liquid to decompose and generate free radicals with strong chemical activity, which quickly chemically modify the hard and brittle materials under the action of mechanical force, and promote the formation of a relatively softer modified layer on the surface of the substrate; under the action of microwave heating, the thermosensitive active grinding liquid, as a conductive medium, transfers heat to the surface of the workpiece to be processed, thereby improving the plastic deformation capacity of the modified layer material on the surface of the workpiece; the diamond fixed abrasive grinding disc mechanically removes the surface material of the workpiece softened by microwave heating, the low-hardness modified layer is broken and layered, and the rapidly exposed new surface is further modified and removed, thereby obtaining high processing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-precision machining of difficult-to-machine materials, and relates to an oil-based thermosensitive active grinding fluid and a microwave-assisted fixed abrasive grinding method. The grinding fluid and the grinding method are particularly suitable for brittle crystal materials. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Brittle crystal materials, such as single-crystalline silicon, alumina, silicon carbide, and gallium nitride, are core materials in the fields of energy, communication, transportation, and medical treatment. Power devices and radio frequency devices prepared from brittle semiconductor materials are widely used in modern industrial fields such as new energy vehicles, 5G communication, photovoltaic power generation, rail transit, smart grid, and aerospace. However, the above brittle crystal materials have characteristics such as high hardness, high brittleness, and stable chemical properties, and are typical difficult-to-machine materials. The surface quality and machining accuracy of the workpiece will significantly affect the performance, energy consumption, and service life of semiconductor devices. Therefore, it is particularly important to achieve high-efficiency, low-damage, and ultra-precision machining of brittle materials.

[0004] At home and abroad, grinding, lapping, and polishing are mainly used to perform ultra-precision machining on brittle crystal materials formed by wire cutting to control the shape accuracy, surface quality, and subsurface damage depth. Lapping usually uses free diamond abrasives with a size of 1 - 15 μm to mechanically remove the damaged layer generated during the grinding process. CN110421481A provides a method for mechanically lapping hard and brittle sapphire with free abrasives. However, due to the material characteristics of high hardness and strong wear resistance, as well as the machining method of removing materials by three-body wear, the material removal rate of free abrasive lapping of sapphire is extremely low, and the surface shape accuracy of the workpiece is poor. CN110539209A provides a method for processing sapphire wafers by combining free abrasive lapping and fixed abrasive lapping. The fixed abrasive grinding wheel lapping can effectively increase the lapping pressure, improve the material removal rate, and obtain high machining accuracy at the same time. However, the machining method of removing materials by two-body wear results in relatively poor lapping surface and subsurface quality, significantly increasing the time and cost of subsequent chemical mechanical polishing treatment. In view of the material characteristics of high hardness, strong wear resistance, and high brittleness of the third-generation semiconductor materials, the existing lapping methods for machining hard and brittle materials have problems of extremely low efficiency or poor machining surface quality. There is an urgent need to develop a lapping method that can balance surface quality and machining efficiency, reduce the manufacturing and processing costs of the entire brittle material, especially hard and brittle materials, and accelerate the development of high-performance semiconductor devices. Summary of the Invention

[0005] Aiming at the prominent contradiction between the lapping efficiency and the surface quality of difficult-to-machine brittle crystal materials, the present invention provides an oil-based thermosensitive active grinding fluid and a microwave-assisted fixed abrasive grinding method.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides an oil-based thermosensitive active polishing fluid, comprising the following components: 0.5% to 5% by mass of propylene glycol, 0.5% to 5% by mass of triethanolamine, 1% to 10% by mass of a thermosensitive oxidant, and the remainder being vegetable oil.

[0008] In some embodiments, the heat-sensitive oxidant is selected from a combination of one or more of hydrogen peroxide, dicyclohexyl peroxycarbonate (DCPD) or diisopropyl peroxydicarbonate (IPP).

[0009] Thermal decomposition initiator refers to a thermal decomposition type initiator that can decompose under heat to produce free radicals to carry out controllable chemical modification of hard and brittle materials under the action of mechanical force.

[0010] The main working principle of oil-based thermosensitive active grinding fluid: microwave-induced decomposition of thermal decomposition initiators in thermosensitive active grinding fluid produces highly chemically active free radicals, which quickly chemically modify hard and brittle materials under mechanical force, and promote the formation of a relatively softer modified layer on the surface of the substrate; under the action of microwave heating, the thermosensitive active grinding fluid acts as a conductive medium to transfer heat to the surface of the workpiece to be processed, thereby improving the plastic deformation capacity of the modified layer material on the surface of the workpiece; the diamond-bonded abrasive disc mechanically removes the surface material of the workpiece softened by microwave heating, the low-hardness modified layer is broken and layered, and the rapidly exposed new surface is further modified and removed, thereby obtaining high processing efficiency; propylene glycol and triethanolamine are used to synergistically regulate the contact stress between the diamond abrasive and the modified layer, thereby achieving high-efficiency, low-damage ultra-precision grinding of difficult-to-process hard and brittle materials.

[0011] Specifically, the equations for the thermal decomposition reactions of organic peroxide thermal decomposition initiators dicyclohexyl peroxycarbonate (DCPD) and diisopropyl peroxydicarbonate (IPP) are as follows:

[0012]

[0013] The equation for the thermal decomposition reaction of inorganic peroxide thermal decomposition initiator hydrogen peroxide is as follows:

[0014]

[0015] The chemical equation for the reaction between the surface of brittle crystalline materials and free radicals is as follows:

[0016]

[0017] Among them, B is the brittle workpiece material.

[0018] In some embodiments, the vegetable oil is soybean oil, palm oil, or rapeseed oil.

[0019] In a second aspect, the present invention provides a method for preparing the oil-based heat-sensitive active polishing liquid, comprising the following steps:

[0020] After propylene glycol, triethanolamine and vegetable oil are mixed evenly according to a certain proportion, a heat-sensitive oxidant is added to the mixed solution and mixed evenly to obtain a grinding solution.

[0021] In a third aspect, the present invention provides a microwave-assisted fixed abrasive grinding method, comprising the following steps: adding the oil-based heat-sensitive active grinding fluid to a fixed abrasive grinding disc;

[0022] Drive the workpiece to be ground and the grinding disc to rotate and grind;

[0023] Microwaves are used to heat the grinding system and induce the decomposition of the thermosensitive active grinding fluid in the oil engine thermosensitive active grinding fluid to generate active free radicals to chemically modify the workpiece under mechanical stress;

[0024] Grinding removes the softened material on the workpiece surface.

[0025] Chemical modification can reduce the hardness of the workpiece surface material and improve the fracture toughness of brittle materials, while using the heating effect of microwaves to improve the plasticity of the modified layer material.

[0026] By configuring an oil-based thermosensitive active grinding fluid, a microwave-consolidated diamond abrasive grinding system with microwave heating function and adjustable temperature is constructed. Microwave energy is used to heat the workpiece to be processed to improve the plastic deformation ability of the material. At the same time, the thermal decomposition initiator in the thermosensitive active grinding fluid is induced to decompose to produce active free radicals to chemically modify the surface material of the workpiece under mechanical stress, thereby inducing the formation of a modified layer with low hardness, low elastic modulus and high fracture toughness on the surface of the brittle workpiece material, increasing the critical cutting depth of the material's brittle-plastic transition removal, reducing or even eliminating the processing damage caused by the removal of a single mechanical stress, and improving the material removal rate and processing surface quality.

[0027] In some embodiments, the critical grinding depth d for removing the softened material on the workpiece surface is c The expression is as follows:

[0028] d c =λ(H / E) 1 / 2 (K c / H) 2 ;

[0029] Where, λ is the brittle-to-plastic transition factor of the brittle material, H is the hardness of the material after microwave softening, E is the elastic modulus of the material after microwave softening, and K cis the fracture toughness of the material after microwave softening.

[0030] In some embodiments, the grinding system is heated to 40 - 300 °C by microwave.

[0031] In some embodiments, the particle size of the diamond abrasive in the grinding disc is 0.2 - 3.0 μm.

[0032] In some embodiments, the grinding pressure is 50 - 100 g / cm 2 ;

[0033] Preferably, the rotational speed of the grinding disc is 150 - 300 rpm;

[0034] Preferably, the rotational speed of the workpiece is 100 - 150 rpm;

[0035] Preferably, the flow rate of the grinding fluid is 50 - 100 mL / min.

[0036] In some embodiments, it further includes measuring the surface roughness S of the workpiece after grinding by using an atomic force microscope a and observing the subsurface of the workpiece after grinding by using a focused ion beam - transmission electron microscopy technique.

[0037] In some embodiments, the steps for building a microwave - assisted fixed - abrasive grinding system are as follows:

[0038] A microwave radiation shielding cover with a visible window is arranged outside the grinding platform;

[0039] Inside the shielding cover, one or more microwave generators are arranged concentratedly or uniformly along the grinding platform, and the distance between the microwave generator and the workpiece to be processed is 5 - 10 cm;

[0040] The workpiece to be processed and the grinding disc are respectively installed, and subsequent operations can be carried out.

[0041] The beneficial effects obtained by one or more of the above - mentioned embodiments of the present invention are as follows:

[0042] 1. The present invention uses a thermosensitive active grinding fluid to perform microwave - assisted controllable chemical modification on the workpiece under mechanical force, softens the surface material of the workpiece, increases the critical cutting depth for brittle - plastic transformation removal of the material, thereby reducing or even eliminating the processing damage caused by single mechanical stress removal, and at the same time improving the material removal rate. There are no micro - crack damages and fractures on the surface of the ground workpiece, and the surface roughness S of the workpiece a can reach 1.0 - 10.0 nm. The material removal rate can reach 15.0 - 30.0 μm / min. The present invention can simultaneously achieve ultra - precision grinding processing of difficult - to - machine materials with high surface quality, low mechanical damage, and high material removal rate.

[0043] 2. The present invention utilizes a fixed abrasive grinding disc, where the density distribution of abrasive grains is controllable, the grinding efficiency is high, the wear resistance of the grinding disc is good, and the durability is high. At the same time, the active grinding fluid performs microwave-assisted controllable chemical modification on the workpiece under mechanical force, expands the controllable speed range of chemical reactions, adapts to mechanical forces under different parameters, regulates the synergistic effect of chemical and mechanical grinding, effectively improves the surface quality and processing efficiency of materials, and can achieve high-efficiency and low-damage ultra-precision grinding of hard and brittle materials that are difficult to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0045] Figure 1 SEM micrographs (a and b) of diamond abrasive grains of the diamond fixed abrasive grinding disc prepared in the microwave-assisted fixed abrasive grinding method of the present invention and a picture of the diamond fixed abrasive grinding disc (c);

[0046] Figure 2 Schematic diagram of the grinding platform in the microwave-assisted fixed abrasive grinding method of the present invention, 1 - workbench, 2 - workpiece to be processed, 3 - liquid pool, 4 - diamond fixed abrasive grinding disc, 5 - chip filtering device, 6 - heat-sensitive active grinding fluid supply device, 7 - heat-sensitive initiator concentration indicating device, 8 - microwave generating device;

[0047] Figure 3 Comparison chart of material removal rates of diamond fixed abrasive grinding of silicon carbide and alumina crystals under the action of deionized water and oil-based heat-sensitive active grinding fluid in the microwave-assisted fixed abrasive grinding method of the present invention;

[0048] Figure 4 SEM micrographs of diamond fixed abrasive grinding of alumina single crystal under the action of deionized water and oil-based heat-sensitive active grinding fluid in the microwave-assisted fixed abrasive grinding method of the present invention;

[0049] Figure 5 Process flow chart of the preparation of oil-based heat-sensitive active grinding fluid and the microwave-assisted fixed abrasive grinding of brittle materials in the microwave-assisted fixed abrasive grinding method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, 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.

[0051] Example 1

[0052] The microwave-assisted fixed abrasive grinding method for brittle materials and the oil-based thermosensitive active grinding fluid of the present invention are further described in conjunction with the embodiments:

[0053] In this embodiment, 2-inch hard and brittle silicon carbide and aluminum oxide wafers are selected as the workpieces to be processed. A laboratory-designed and customized grinding and polishing machine is used as the test platform. The microwave generator can heat the workpiece to be processed and the active grinding liquid to 80°C. The diamond-bonded abrasive disc with an average particle size of 3μm is used to grind the above workpiece. Figure 2 As shown, the grinding process was performed. After grinding, the sample was cleaned with alcohol ultrasonic for 10 minutes. The mass of the workpiece material before and after grinding was weighed using a balance (accuracy 0.001 mg) to calculate the material removal rate; the surface roughness S of the workpiece after grinding was measured using an atomic force microscope. a The measurement range is 50μm×50μm, and the surface of the ground workpiece is observed using a field emission scanning electron microscope.

[0054] The specific implementation steps are as follows:

[0055] S1. Based on the chemical principle that the thermal decomposition initiator interacts with heat to produce free radical active species, and the chemical principle that the free radical active species and inert materials react with each other to form a softening layer, in view of the characteristics of hard and brittle materials with high hardness, great brittleness and stable chemical properties, an active grinding fluid is configured that can generate free radical active species by microwave heating and can controllably chemically modify the workpiece material under mechanical stress:

[0056] S11. In a chemical experiment operation box, pour a certain amount of propylene glycol, triethanolamine and vegetable oil into a beaker in sequence, and mechanically stir and mix at room temperature for 3 to 5 minutes to obtain a propylene glycol-triethanolamine mixed oil solution;

[0057] S12, slowly adding a certain amount of thermal decomposition initiator compound to the propylene glycol-triethanolamine mixed oil solution, mechanically stirring at room temperature for 1 to 2 minutes, dissolving or dispersing the thermal decomposition initiator compound in the propylene glycol-triethanolamine mixed oil solution, and obtaining a grinding liquid with heat-sensitive activity;

[0058] S13, pour the prepared heat-sensitive active grinding liquid into a light-proof reagent bottle for later use.

[0059] S2. Build a microwave-consolidated diamond abrasive grinding platform with microwave heating function and adjustable temperature:

[0060] S21, fix the microwave generator 5 cm away from the contact interface between the workpiece and the grinding disc. The microwave generator can rotate and move, and can focus energy on a designated area;

[0061] S22. Weigh the mass of the workpiece before grinding using a balance. Then, install the double-door shielding cover directly in front of the grinding table. Clamp the workpiece onto the workbench connected to the upper driving motor through vacuum adsorption, and fix the 3-μm-grit vitrified diamond abrasive grinding disc onto the turntable connected to the lower driving motor.

[0062] S23. Add the thermosensitive active grinding fluid configured in S1 to the vitrified diamond abrasive grinding disc at a certain flow rate.

[0063] S3. Based on the composition, content, and solution flow rate of the initiator complex in the thermosensitive active grinding fluid obtained in S1, as well as the hardness, elastic modulus, fracture toughness, and interfacial separation strength of the workpiece material modification layer, set process parameters such as the power of the microwave generator, grinding pressure, grinding disc rotation speed, and workpiece rotation speed. The selection of process parameters is based on the mechanical properties of the workpiece modification layer. Then, start the automatic grinding and polishing machine to perform microwave-assisted mechanical grinding for the microwave heating chemical modification of the workpiece material and the dynamic removal of the modification layer by mechanical grinding:

[0064] The specific operation steps for grinding the workpiece against each other include:

[0065] S31. Start the lower driving motor to drive the vitrified diamond abrasive grinding disc to rotate, start the upper driving motor to drive the workpiece to rotate, and apply a positive pressure to control the grinding of the vitrified diamond abrasive grinding disc against the workpiece.

[0066] S32. Adjust the microwave generator, use microwave energy to heat the workpiece to be processed, and simultaneously induce the decomposition of the thermal decomposition type initiator in the thermosensitive active grinding fluid to generate active free radicals to chemically modify the workpiece under mechanical stress, reducing the hardness and elastic modulus of the workpiece surface material and simultaneously increasing the fracture toughness of brittle materials.

[0067] Based on step S3, grind and remove the softened material on the workpiece surface. The critical cutting depth d c for the diamond abrasive grains to mechanically remove the softened material on the workpiece surface is expressed as follows:

[0068] d c = λ(H / E) 1 / 2 (K c / H) 2 ;

[0069] where λ is the brittle-plastic transformation factor of the photosensitive material, H is the hardness of the photosensitive material, E is the elastic modulus of the photosensitive material, and K c is the fracture toughness of the photosensitive material.

[0070] S33. After 10 to 30 minutes, turn off the testing machine, remove the workpiece, and then use alcohol ultrasonic cleaning for 10 minutes. Use a balance to weigh the mass of the workpiece after grinding, calculate the removal rate of the workpiece material, and use an atomic force microscope to measure the surface roughness S of the workpiece after grinding. a The measurement range is 50μm×50μm, and the surface of the ground workpiece is observed using a field emission scanning electron microscope.

[0071] S34. Measure the surface roughness of the workpiece after grinding using atomic force microscopy a The surface of the workpiece after grinding was observed using a field emission scanning electron microscope, and the sub-surface of the workpiece after grinding was observed using a focused ion beam-transmission electron microscope.

[0072] Grinding liquid: Grinding liquid C, composed of: 94% soybean oil, 5% dicyclohexyl peroxycarbonate (DCPD), 0.5% propylene glycol, and 0.5% triethanolamine.

[0073] Grinding method: Grinding temperature 80°C, grinding pressure 100g / cm 2 The grinding disc speed is 200rpm, the workpiece speed is 50rpm, the grinding liquid flow rate is 50mL / min, the grinding time is 20 minutes, the microwave generator is in working state, and the surface temperature of the grinding disc is ensured to fluctuate around 80°C; the particle size of the diamond abrasive grains in the fixed abrasive grinding disc is 250nm~1000nm.

[0074] Comparative Example 1

[0075] The grinding liquid A is deionized water, and the other conditions are the same as those in Example 1.

[0076] Comparative Example 2

[0077] The grinding liquid B includes: 99% soybean oil, 0.5% propylene glycol, and 0.5% triethanolamine; the other components are the same as those in Example 1.

[0078] Test results:

[0079] like Figure 3 As shown in the figure, the surface roughness S of silicon carbide and aluminum oxide wafers processed by microwave-assisted fixed abrasive grinding with grinding liquid A is a =41.3nm and 36.6nm, workpiece material removal rate MRR =7.3μm / min and 3.9μm / min.

[0080] Surface roughness S of silicon carbide and aluminum oxide wafers machined by microwave-assisted fixed abrasive grinding with grinding fluid B a =33.1nm and 24.8nm, workpiece material removal rate MRR = 6.3μm / min and 2.3μm / min.

[0081] Surface roughness S of silicon carbide and alumina wafers ground by microwave-assisted fixed abrasive grinding with grinding fluid C a were 11.3 nm and 8.6 nm, and the material removal rate MRR of the workpiece was 20.5 μm / min and 10.9 μm / min.

[0082] Figure 4 It is further proved that microwave-assisted fixed abrasive grinding based on oil-based thermosensitive active grinding fluid can effectively reduce the brittle fracture on the surface of silicon carbide and alumina crystals and improve the mechanical damage of the ground surface.

[0083] By comparing the processing effects of diamond fixed abrasive mechanical grinding and microwave-assisted fixed abrasive grinding through the above three groups of experiments, it is found that the processing effect of the grinding processing method of the present invention is significantly better than that of the traditional mechanical grinding processing method.

[0084] In particular, in control group A, deionized water was used. When the microwave heating exceeded 100 °C, high-temperature water vapor would be generated, which posed a certain safety hazard. Therefore, in this embodiment, the temperature was only controlled near 80 °C. However, in the actual processing process, since vegetable oils such as soybean oil and olive oil were used as the base fluid, the temperature could be further increased to 300 °C, which would be more conducive to the dislocation slip of the surface layer material of the modified layer, thereby improving the plastic deformation ability and obtaining better grinding performance.

[0085] Example 2

[0086] Grinding fluid: The composition was: 93% soybean oil, 2% diisopropyl peroxydicarbonate, 4% propylene glycol, 1% triethanolamine. Others were the same as in Example 1.

[0087] Example 3

[0088] Grinding fluid: The composition was: 87% soybean oil, 7% hydrogen peroxide, 2% propylene glycol, 4% triethanolamine. Others were the same as in Example 1.

[0089] Example 4

[0090] Grinding method: The grinding temperature was 200 °C, the grinding pressure was 50 g / cm 2 , the grinding wheel speed was 300 rpm, the workpiece speed was 150 rpm, the grinding fluid flow rate was 70 mL / min, the grinding time was 20 minutes, and the microwave generator was in a working state to ensure that the temperature on the surface of the grinding wheel fluctuated around 200 °C.

[0091] Example 5

[0092] Grinding method: The grinding temperature was 300 °C, the grinding pressure was 100 g / cm 2, the grinding disc rotates at 150 rpm, the workpiece rotates at 150 rpm, the flow rate of the grinding fluid is 100 mL / min, the grinding time is 20 minutes, the microwave generator is in working condition, ensuring that the surface temperature of the grinding disc fluctuates around 300 °C.

[0093] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An oil-based thermosensitive active grinding fluid, characterized in that: It comprises the following components: propylene glycol accounts for 0.5% - 5% by mass percentage, triethanolamine accounts for 0.5% - 5% by mass percentage, the thermosensitive oxidant accounts for 1% - 10% by mass percentage, and the balance is vegetable oil; The thermosensitive oxidant is selected from one or a combination of more than one of hydrogen peroxide, dicyclohexyl peroxydicarbonate or diisopropyl peroxydicarbonate.

2. The oil-based thermosensitive active grinding fluid according to claim 1, wherein: The vegetable oil is soybean oil, palm oil or rapeseed oil.

3. The preparation method of the oil-based thermosensitive active grinding fluid according to claim 1 or 2, characterized in that: It includes the following steps: After mixing propylene glycol, triethanolamine and vegetable oil evenly in proportion, add the thermosensitive oxidant to the mixed solution and mix evenly to obtain the grinding fluid.

4. A microwave-assisted fixed abrasive grinding method, characterized in that: It includes the following steps: adding the oil-based thermosensitive active grinding fluid described in Claim 1 or 2 onto a fixed abrasive grinding disc; Drive the workpiece to be ground and the grinding disc to rotate and grind against each other; Heat the grinding system by microwave, and at the same time induce the decomposition of the thermosensitive oxidant in the oil-based thermosensitive active grinding fluid to generate active free radicals to chemically modify the workpiece under mechanical stress; Just grind and remove the softened material on the surface of the workpiece.

5. The microwave-assisted consolidated abrasive grinding method according to claim 4, characterized in that: Critical grinding depth d for grinding and removing the softened material on the workpiece surface c The expression is as follows: d c = λ(H / E) 1 / 2 (K c / H) 2 ; where λ is the brittle-plastic transition factor of the brittle material, H is the hardness of the material after microwave softening, E is the elastic modulus of the material after microwave softening, and K c is the fracture toughness of the material after microwave softening.

6. The microwave-assisted fixed abrasive grinding method according to Claim 4 includes the following steps: heating the grinding system to 40 - 300 °C by microwave.

7. The microwave-assisted fixed abrasive grinding method according to Claim 4 includes the following steps: the particle size of the diamond abrasive in the grinding disc is 0.2 - 3.0 μm.

8. The microwave-assisted fixed abrasive grinding method according to claim 4, comprising the following steps: grinding at a pressure of 50 to 100 g / cm 2 .

9. The microwave-assisted fixed abrasive grinding method according to Claim 8 includes the following steps: the rotational speed of the grinding disc is 150 - 300 rpm.

10. For the microwave-assisted fixed abrasive grinding method according to Claim 9, the rotational speed of the workpiece is 100 - 150 rpm.

11. For the microwave-assisted fixed abrasive grinding method according to Claim 4, the flow rate of the grinding fluid is 50 - 100 mL / min.

12. The microwave-assisted fixed abrasive lapping method according to claim 4, comprising the following steps: further comprising measuring the surface roughness S of the workpiece after lapping by using an atomic force microscope a and observing the subsurface of the workpiece after lapping by using a focused ion beam - transmission electron microscopy technique.

13. The microwave-assisted fixed abrasive grinding method according to Claim 4 includes the following steps: the steps for building the microwave-assisted fixed abrasive grinding system are: Set up a microwave radiation shielding cover with a visual window outside the grinding platform; Inside the shielding cover, one or more microwave generators are centrally or evenly arranged along the grinding platform, and the distance between the microwave generator and the workpiece to be processed is 5 - 10 cm; Install the workpiece to be processed and the grinding disc respectively, and subsequent operations can be carried out.

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