Chemical mechanical grinding system and method for hard and brittle semiconductor wafer

Abstract

The invention relates to a chemical mechanical grinding system and method for a hard and brittle semiconductor wafer, and the chemical mechanical grinding method comprises the following steps: preparing an oil-based thermal activity-optical activity composite grinding fluid by adopting an organic thermal decomposition type oxidizing agent, an organic optical decomposition oxidizing agent, polyethylene glycol, glycerol and vegetable oil; building an ultraviolet light-diamond abrasive grinding wheel chemical mechanical grinding platform which has an ultraviolet light irradiation function and is adjustable and controllable in irradiation intensity and ultraviolet light wavelength; the chemical mechanical grinding platform and the minimal quantity lubrication liquid supply device are started, and the wafer to be machined and the diamond abrasive grinding wheel are controlled to rotate relative to each other for opposite grinding; turning on an ultraviolet light generator to accurately irradiate the thermal activity-optical activity composite grinding liquid drops on the surface of the wafer, inducing a thermal decomposition type oxidizing agent and an optical decomposition type oxidizing agent to generate active free radicals by utilizing grinding heat energy and ultraviolet light irradiation energy, and initiating a free radical oxidation reaction of a wafer surface layer material to form an oxidation layer with low interface bonding force; the oxide layer on the surface of the wafer is removed through small-load micro-cutting of the diamond abrasive, and the semiconductor wafer with the subsurface almost free of mechanical damage is efficiently obtained.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-precision processing of semiconductor wafers, and in particular to a chemical mechanical grinding method for hard and brittle semiconductor wafers. Background Art

[0002] Semiconductor materials, such as single crystal silicon, silicon carbide and gallium nitride, are core materials in the fields of energy, communications, transportation and medicine. Power devices and radio frequency devices made of semiconductor materials are widely used in modern industrial fields such as new energy vehicles, 5G communications, photovoltaic power generation, rail transportation, smart grids and aerospace. However, semiconductor materials usually have extremely high hardness, extremely low fracture toughness, extremely strong wear resistance and stable chemical properties, and are a typical type of difficult-to-process material. The surface quality and processing accuracy of semiconductor wafers will significantly affect the service performance, energy consumption and life of power devices and radio frequency devices. Therefore, it is urgent to achieve high-efficiency, low-damage and ultra-precision processing of semiconductor wafers.

[0003] At present, grinding and polishing are mainly used at home and abroad to perform ultra-precision processing on semiconductor wafers cut by wire cutting to control shape accuracy, surface quality and sub-surface damage depth. Grinding usually uses 1-15μm free diamond abrasives to mechanically remove the damage layer produced by the wire saw cutting process. CN117645841A and CN117447963A provide a method for mechanical grinding of hard and brittle silicon carbide wafers with free abrasives, but the material properties of high hardness and strong wear resistance and the processing method of removing materials by three-body wear result in extremely low material removal rate and poor workpiece surface shape accuracy of free abrasive grinding of silicon carbide. In view of the material properties of high hardness, strong wear resistance and high brittleness of the third-generation semiconductor materials, the existing grinding methods for processing hard and brittle semiconductor materials are more or less faced with the problems of low efficiency or poor processing accuracy. It is urgent to develop an ultra-precision grinding method that can take into account both processing quality and processing efficiency, reduce the manufacturing and processing costs of the entire brittle semiconductor material, especially hard and brittle semiconductor materials, and accelerate the development of high-efficiency semiconductor devices.

[0004] Patent CN 116038551 A discloses a photochemical mechanical polishing method, which uses ultraviolet radiation energy to induce the decomposition of a photoinitiator compound in an aqueous photosensitive polishing liquid to produce benzoyl radicals and alkyl radical active species to chemically modify the workpiece under the action of mechanical force, inducing the formation of a modified layer with low hardness, small elastic modulus and high fracture toughness on the surface of the workpiece. Finally, the modified layer is ground with a grinding disc to increase the critical cutting depth of the material brittle-plastic transition removal, reduce or even eliminate the processing damage caused by the removal of a single mechanical stress, and improve the material removal rate and high processing efficiency. However, the photochemical mechanical polishing method proposed in the patent has the following three limitations: (1) Due to the inherent limitations of the grinding equipment, the photochemical mechanical polishing method proposed in the patent is only applicable to the surface flattening processing of materials, that is, it can only be used for plane processing, and cannot process curved surfaces and complex microstructures and surfaces; (2) The photoactive grinding fluid involved in the patent is an aqueous grinding fluid using deionized water as the base fluid. Although its excellent cooling performance is suitable for grinding, its weak lubricity leads to severe grinding of ultra-fine abrasive wheels during grinding, requiring repeated dressing of the grinding wheel, reducing processing accuracy and efficiency. At the same time, the aqueous grinding fluid has a certain degree of corrosiveness, which will significantly affect the high speed of the grinder. The life and accuracy of the air-floating spindle are shortened, so it is useless for ultra-precision grinding of semiconductor wafers; (3) The temperature of the grinding interface during grinding is usually at room temperature. Based on this, the photoactive grinding fluid proposed in this patent is a solution that is only sensitive to ultraviolet light. It uses the energy of ultraviolet light irradiation to induce the solution to produce benzoyl radicals and alkyl radicals. Therefore, it can be used well for grinding. However, the solution cannot use thermal energy to decompose and produce free radicals. Grinding will generate a lot of grinding heat, and the temperature can be as high as 200°C or even higher. Excessive grinding heat will cause serious thermal damage. Therefore, it is necessary to invent a thermally active grinding fluid that can absorb grinding heat for grinding.

[0005] Patent CN110842761A discloses a photocatalytic high-energy field assisted chemical-mechanical composite micro-grinding method, which performs composite micro-grinding processing on tiny parts of silicon-based materials. The method is characterized in that: an alkaline chemical modification liquid with deionized water as the base liquid is supplied to the surface of the silicon-based material parts, and an ultraviolet laser is first used to scan along a preset path. Under ultraviolet light catalysis, the material in the scanned area is photocatalytically advanced oxidized and modified into an oxide layer; then the infrared laser is switched to scan again along the original path, and the oxide layer continues to be chemically modified into a silicate layer under the assistance of a high-energy field; the laser is turned off and the micro-abrasive tool is started, and the micro-abrasive tool mechanically removes the silicate layer along the laser scanning path; the above-mentioned ultraviolet-infrared-chemical-mechanical composite micro-grinding process is recycled until the processing size requirements are met; finally, a weak acid detergent is switched to rinse, neutralize and recover the residual liquid to complete the processing. However, the photocatalytic high-energy field assisted chemical mechanical composite micro-grinding method proposed in the patent has the following three limitations: (1) Due to the limitation of the laser spot size (the spot diameter ranges from 10 to 500 microns, less than 1 mm), the size of the oxide layer produced by the synergistic modification of the ultraviolet laser and the infrared laser is also less than 1 mm. Therefore, the diameter of the micro-grinding rod of the invention patent can only be less than 1 mm, usually in the range of 0.2 to 1 mm. As a result, the grinding method proposed in the patent is only applicable to the processing of micro-parts and cannot be used for high-efficiency ultra-precision processing of large-sized parts such as semiconductor wafers (diameter 120 to 200 mm); (2) The alkaline chemical modification liquid involved in the patent is an alkaline grinding fluid using deionized water as the base liquid. Although the water content can be reduced by adding rust inhibitors, the alkaline chemical modification liquid used in the patent is not suitable for high-precision machining of large-sized parts such as semiconductor wafers (diameter 120 to 200 mm). The grinding fluid can cause rust on the spindle, but the weak alkalinity generated by the sodium hydroxide in the solution can corrode the machine tool body. At the same time, the weak lubricity of the aqueous grinding fluid leads to severe grinding of the ultrafine abrasive wheel during grinding, and the grinding wheel needs to be repeatedly dressed, which reduces the processing accuracy and efficiency. Therefore, it cannot be used for ultra-precision grinding of hard and brittle semiconductor wafers; (3) The alkaline chemical modification fluid provided by the patent utilizes the inorganic oxidant hydrogen peroxide (H2O2) in the solution to absorb ultraviolet laser energy to produce hydroxyl radicals for oxidation. However, the inorganic oxidant cannot be dissolved in oily solvents such as vegetable oil. Therefore, it is impossible to prepare a grinding fluid with both lubrication and oxidation properties. At the same time, the solution only produces a single carboxyl radical, which often reacts with the dissolved oxygen in the alkaline solution to produce an annihilation reaction, resulting in the failure of the oxidation activity. In view of this, the invention patent proposes further high-energy infrared laser processing of the pre-processing area to obtain the required modified layer. However, the high-energy beam generated by the infrared laser can easily cause thermal damage and thermal cracks in the non-processing area. For the processing of semiconductor wafers, once thermal cracks occur, ultra-thin wafers (thickness less than 0.5 mm) will be fragmented. Therefore, the photocatalytic high-energy field assisted chemical-mechanical composite micro-grinding method cannot be used for high-efficiency ultra-precision processing of hard and brittle semiconductor wafers. Summary of the invention

[0006] In view of the prominent contradiction between the grinding efficiency and surface quality of hard and brittle semiconductor wafers that are difficult to process, the present invention provides an ultra-precision chemical mechanical grinding method and a thermally active-photoactive composite grinding fluid. By configuring an oil-based thermally active-photoactive composite grinding fluid, a UV-diamond abrasive wheel chemical mechanical grinding system with UV irradiation function and adjustable and controllable irradiation intensity and UV wavelength is constructed. Grinding heat energy and UV irradiation energy are used to induce organic thermal decomposition and photodecomposition oxidants to produce active free radicals to oxidize the surface material of the semiconductor wafer under mechanical stress, thereby inducing the formation of an oxide layer with low hardness and low interface bonding strength on the surface of the wafer. The diamond abrasive uses small load micro-cutting to efficiently remove the oxide layer on the wafer surface, thereby reducing or even eliminating the processing damage caused by single mechanical grinding with high mechanical stress removal, while improving the material removal rate and processing quality.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, the present invention provides a chemical mechanical grinding system for hard and brittle semiconductor wafers, including a machine tool body, on which a first linear drive device and a second linear drive device are arranged, the first linear drive device realizes the movement of the first high-speed air-floating spindle in the X direction, and the second linear drive device realizes the movement of the second high-speed air-floating spindle in the Z direction, the first high-speed air-floating spindle drives the semiconductor wafer to rotate; the second high-speed air-floating spindle drives the diamond abrasive grinding wheel to rotate; an ultraviolet light generator and a micro-lubrication device are arranged on the outer side of the semiconductor wafer; the micro-lubrication device atomizes an oil-based thermally active-photoactive composite grinding fluid into small droplets according to a certain amount and then sprays them onto the semiconductor wafer; the ultraviolet light generator emits ultraviolet light, and the grinding heat energy and ultraviolet light irradiation energy induce the decomposition of organic thermal decomposition and photodecomposition oxidants in the oil-based thermally active-photoactive composite grinding fluid to generate active free radicals to carry out free radical oxidation reaction on the surface material of the wafer under mechanical stress, thereby forming an oxide layer with low interface bonding strength.

[0009] The chemical mechanical grinding system proposed in this patent utilizes the low energy and large-area irradiation characteristics of ultraviolet light sources (irradiation area can reach centimeters), combined with ultra-fine diamond abrasive wheels with interchangeable shapes and sizes, to achieve flattening of semiconductor wafers and ultra-precision processing of complex curved and shaped surfaces of hard and brittle materials.

[0010] In a second aspect, the present invention provides a chemical mechanical grinding method for hard and brittle semiconductor wafers, and the specific implementation steps of the grinding process are as follows:

[0011] S1, the second high-speed air-floating spindle drives the diamond abrasive grinding wheel to rotate, the first high-speed air-floating spindle drives the wafer to rotate, the micro-lubrication device atomizes the oil-based thermal-active-photoactive composite grinding fluid into small droplets according to a certain amount and sprays them onto the semiconductor wafer, and at the same time, the first linear drive device and the second linear drive device apply the feed amount in the X direction and the grinding depth in the Z direction, and finally control the diamond grinding wheel and the wafer to rotate relative to each other for grinding;

[0012] S2. Adjust the ultraviolet light generator, and use the grinding heat and ultraviolet radiation to induce the decomposition of organic thermal decomposition type and photodecomposition type oxidants in the oil-based thermally active-photoactive composite grinding fluid to produce active free radicals, which react with the wafer surface material under mechanical stress to form an oxide layer with low interface bonding strength; based on step S1, grind away the oxide layer on the wafer surface.

[0013] As a further technical solution, the critical grinding depth d for mechanical removal of the oxide layer by diamond abrasives c The expression is as follows:

[0014] d c =λ(H / E) 1 / 2 (K c / H) 2

[0015] Where λ is the brittle-to-plastic transition factor of the hard-brittle semiconductor material, H is the hardness of the oxide layer on the wafer surface, E is the elastic modulus of the oxide layer on the wafer surface, and K c is the fracture toughness of the oxide layer on the wafer surface;

[0016] As a further technical solution, after step S2 is completed, the surface roughness S of the ground wafer can also be measured using a white light interferometer. a The surface of the workpiece after grinding was observed using a field emission scanning electron microscope, and the damage type and scale of the wafer subsurface after grinding were observed using a focused ion beam-transmission electron microscope.

[0017] Preferably, the power of the ultraviolet light generator is 50-200W, the ultraviolet light band is 100-400nm, the diamond abrasive grinding wheel is a metal bond or a ceramic bond diamond grinding wheel, and the diamond particle size is 0.5-10.0μm.

[0018] Preferably, the process parameters include workpiece rotation speed, grinding wheel rotation speed, workpiece feed speed, grinding wheel grinding depth and grinding fluid flow rate, the workpiece rotation speed is 100-2000rpm, the grinding wheel rotation speed is 500-3000rpm, the workpiece feed speed is 0.1-1mm / min, the grinding wheel grinding depth is 0.5-5μm, and the grinding fluid flow rate is 10-100mL / h.

[0019] Preferably, in the semiconductor wafer chemical mechanical grinding method, the grinding heat and ultraviolet radiation can induce the thermal decomposition type and photodecomposition type organic oxidant in the oil-based thermally active-photoactive composite grinding fluid to decompose and produce active carbon free radicals and carboxyl free radicals in the following thermochemical and photochemical reactions:

[0020]

[0021] The chemical reaction equation for the formation of the oxide layer on the wafer surface is as follows:

[0022] M+HOCOCH2CH2C(CH3)(CN)·=HOCOCH2CH2C(CH3)(CN)M

[0023] M+·NC(CH3)(CN)CH2CH2COOH=MNC(CH3)(CN)CH2CH2COOH

[0024] M+εHOCH2CH2OC6H4CO·=HOCH2CH2OC6H4COM

[0025] M+·C(CH3)2OH=MC(CH3)2OH

[0026] Among them, M is a hard and brittle semiconductor material.

[0027] Another aspect of the present invention provides an oil-based thermally active-photoactive composite grinding fluid for chemical mechanical grinding of hard and brittle semiconductor wafers. The steps of preparing the oil-based thermally active-photoactive composite grinding fluid are as follows:

[0028] S1, mixing polyethylene glycol, glycerol and vegetable oil and stirring to obtain a polyethylene glycol-glycerol mixed oil solution;

[0029] S2. According to the material composition and chemical bond type of the hard and brittle semiconductor material, the corresponding organic thermal decomposition type oxidant and organic photodecomposition type oxidant are selected to prepare a thermally active and photoactive oxidant complex, and the active-photoactive oxidant complex is added to a polyethylene glycol-propylene glycol mixed oil solution, and the complex is dissolved in the polyethylene glycol-propylene glycol mixed oil solution by heating and stirring in a water bath to obtain an oil-based thermally active-photoactive composite grinding fluid.

[0030] Preferably, the organic thermal decomposition type oxidant is azobiscyanovaleric acid (ACVA), azobisisobutyric acid (AIBME) or azobisisobutylamidine dihydrochloride (AIBA), the organic photodecomposition type oxidant is hydroxyacetophenone (2959), trimethylbenzoylphenylphosphonate (TPO) or trimethylbenzoyl (819), the thermally active-photoactive oxidant complex contains at least one thermally active oxidant and one photoactive oxidant or multiple thermally active and photoactive oxidants, the mass percentage of the thermally active oxidant to the photoactive oxidant is between 10:1 and 1:10, and the mass percentage of the thermally active-photoactive oxidant complex is between 1.0% and 10.0%.

[0031] Preferably, the mass percentage of the polyethylene glycol and glycerol is between 10% and 20%, which is used to adjust the viscosity and cooling performance of the grinding fluid.

[0032] Preferably, the vegetable oil is one or more of castor oil, olive oil, soybean oil, and rapeseed oil, which is used as a base liquid to dissolve organic thermally active and photoactive oxidants and adjust the lubricating properties of the grinding fluid. Considering that grinding will generate a large amount of grinding heat, and excessive grinding heat will cause thermal damage to the workpiece and the grinding wheel surface, the present invention provides an oily thermally active-photoactive composite grinding fluid using vegetable oil as a base liquid. During grinding, the organic thermal decomposition type oxidant in the composite grinding fluid will absorb part of the grinding heat when it is cracked, which helps to inhibit the thermal damage to the workpiece and the grinding wheel surface. At the same time, a variety of active carbon free radicals and carboxyl free radicals are generated by ultraviolet light energy and grinding heat energy, avoiding the oxidation failure problem caused by the annihilation effect of a single free radical species. Moreover, the lubricating properties provided by the base liquid vegetable oil can effectively reduce the wear of the ultrafine abrasive grinding wheel, and ultimately improve the service life and processing efficiency of the grinding wheel.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. The present invention uses oil-based thermal-photoactive composite grinding fluid to grind the surface material of semiconductor wafers under mechanical force and controllable free radical oxidation by ultraviolet radiation energy, inducing the formation of an oxide layer with low interface bonding strength on the surface of the wafer, achieving high-efficiency removal of diamond abrasives with low load, thereby reducing or even eliminating the processing damage caused by high mechanical stress removal of single mechanical grinding. The surface of the wafer after chemical mechanical grinding has no microcracks and breakage, and the surface roughness of the workpiece is S a The thickness of the damage layer is less than 2.0 nm, the subsurface of the workpiece is free of crack damage, and the thickness of the damage layer is less than 200 nm. The present invention can simultaneously realize ultra-precision grinding of hard and brittle semiconductor materials with high surface quality, low mechanical damage and high material removal rate.

[0035] 2. The present invention utilizes a metal binder or a ceramic binder ultrafine diamond abrasive grinding wheel with high grinding efficiency and good surface accuracy. At the same time, the thermally active-photoactive composite grinding fluid oxidizes the surface material of the semiconductor wafer under the action of mechanical force, expands the controllable speed range of the free radical oxidation reaction, adapts to the mechanical force under different parameters, regulates the synergistic effect of chemical and mechanical grinding, effectively reduces the wear rate of the ultrafine diamond abrasive, increases the service life of the grinding wheel, reduces the number of dressing times of the grinding wheel, and can achieve high-efficiency ultra-precision grinding of hard, brittle and difficult-to-process semiconductor materials.

[0036] 3. Compared with the existing chemical mechanical grinding method or high-energy field assisted chemical mechanical method, the present invention utilizes the characteristics of grinding wheel grinding. By changing the size and shape of the ultrafine diamond abrasive grinding wheel, it can not only achieve high-efficiency ultra-precision flattening processing of semiconductor wafers, but also can be used for high-efficiency ultra-precision processing of complex curved surfaces and shapes of hard and brittle materials. At the same time, the vegetable oil-based thermally active-photoactive composite grinding fluid provided by the patent of the present invention can generate a variety of active carbon free radicals and carboxyl free radicals with the help of grinding heat energy and ultraviolet light energy, avoiding the oxidation failure problem caused by the annihilation effect of a single free radical species, and the cracking of the organic thermal decomposition type oxidant can absorb part of the grinding heat, avoiding thermal damage to the workpiece and the grinding wheel surface. Finally, with the help of the lubricating properties provided by the base liquid vegetable oil, the wear of the ultrafine abrasive grinding wheel can be effectively reduced, and the service life and processing efficiency of the grinding wheel can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the grinding system in the chemical mechanical grinding method of the present invention, 1-machine tool body, 2-left linear motor, 3-right linear motor, 4-left high-speed air-floating spindle, 5-right high-speed air-floating spindle, 6-vacuum adsorption fixture, 7-ultraviolet light generator, 8-grinding wheel fixture, 9-diamond abrasive grinding wheel, 10-semiconductor wafer, 11-oil-based thermally active-photoactive composite grinding droplets, 12-micro-lubrication device;

[0038] FIG. 2( a ), FIG. 2( b ), and FIG. 2( c ) are diagrams showing the oil-based thermally active-photoactive composite grinding fluid prepared in the chemical mechanical grinding method of the present invention and the processing diagram of the gallium nitride wafer by ultraviolet irradiation chemical mechanical grinding;

[0039] Figures 3(a), 3(b), 3(c), 3(d), 3(e), and 3(f) are comparison diagrams of the surface morphology and roughness of gallium nitride wafers ground by a metal bond diamond grinding wheel under the action of a vegetable oil base fluid (grinding process A) and an oil-based thermally active-photoactive composite grinding fluid (grinding processes B and C) in the chemical mechanical grinding method of the present invention;

[0040] FIG. 4( a ) and FIG. 4( b ) are TEM micrographs of the subsurface damage layer of a gallium nitride wafer ground by a metal bond diamond grinding wheel under the action of a vegetable oil base fluid (grinding process A) and an oil-based thermally active-photoactive composite grinding fluid (grinding process C) in the chemical mechanical grinding method of the present invention;

[0041] Figure 5 A process flow chart of the preparation of an oil-based thermally active-photoactive composite grinding fluid in the chemical mechanical grinding method of the present invention and the chemical mechanical grinding of hard and brittle semiconductor wafers. DETAILED DESCRIPTION

[0042] It should be noted that the following detailed descriptions are illustrative and 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 meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0044] The present embodiment discloses a chemical mechanical grinding system and method for hard and brittle semiconductor wafers, which utilizes a thermally active-photoactive grinding fluid to grind the semiconductor material through heat and ultraviolet light-controlled free radical oxidation, thereby inducing oxidation of the semiconductor surface material to form an oxide layer with low hardness and low interface binding energy, and then using diamond abrasives to micro-cut with a small load to remove the oxide layer on the wafer surface, thereby increasing the material removal rate while reducing the processing damage caused by the removal of a single high mechanical stress, thereby obtaining a semiconductor wafer with sub-surface nearly free of mechanical damage, thereby greatly reducing the processing time of subsequent chemical mechanical polishing, and ultimately reducing the manufacturing and processing cost of the entire semiconductor wafer, thereby accelerating the development of high-efficiency semiconductor devices.

[0045] The present invention is described in detail below in conjunction with the accompanying drawings:

[0046] like Figure 1As shown, the chemical mechanical grinding system for hard and brittle semiconductor wafers provided in this embodiment includes a machine tool body 1, on which a left linear motor 2 and a right linear motor 3 are arranged, the left linear motor 2 realizes the movement of the left high-speed air-floating spindle 4 in the X direction, and the right linear motor 3 realizes the movement of the right high-speed air-floating spindle 5 in the Z direction, the left high-speed air-floating spindle 4 is installed with a vacuum adsorption fixture 6, the vacuum adsorption fixture 6 is used to fix the semiconductor wafer 10, and the left high-speed air-floating spindle 4 drives the semiconductor wafer 10 to rotate; the right high-speed air-floating spindle 5 is installed with a grinding wheel fixture 8, and the grinding wheel fixture 8 fixes the diamond Abrasive grinding wheel, the right high-speed air-floating spindle 5 drives the diamond abrasive grinding wheel to rotate; an ultraviolet light generator 7 and a micro-lubrication device 12 are arranged on the outside of the semiconductor wafer; the micro-lubrication device 12 atomizes the oil-based thermally active-photoactive composite grinding fluid into small droplets according to a certain amount and then sprays them onto the semiconductor wafer; the ultraviolet light generator 7 emits ultraviolet light, and the grinding heat energy and ultraviolet light irradiation can induce the organic thermal decomposition type and photodecomposition type oxidant in the oil-based thermally active-photoactive composite grinding fluid to decompose and generate active free radicals to carry out free radical oxidation reaction on the surface material of the wafer under the action of mechanical stress, thereby forming an oxide layer with low interface bonding strength.

[0047] Based on the above system, this embodiment also provides a chemical mechanical grinding method for hard and brittle semiconductor wafers and a thermally active-photoactive composite grinding fluid. The technical content, objectives and effects of the present invention will be described in detail below in conjunction with the accompanying drawings of the specification. Figure 5 As shown, a chemical mechanical grinding method for hard and brittle semiconductor wafers, the specific steps are as follows:

[0048] S1. Prepare oil-based thermally active and photoactive composite grinding fluid;

[0049] S2. Build a UV-diamond abrasive wheel chemical mechanical grinding system with UV irradiation function and adjustable and controllable irradiation emphasis and UV wavelength;

[0050] S3. Adjust the process parameters of chemical mechanical grinding to grind the oxide layer with low interfacial bonding force modified by the thermally active-photoactive composite grinding fluid on the surface of the wafer.

[0051] Specifically, the process parameters in step S3 include workpiece rotation speed, grinding wheel rotation speed, workpiece feed speed, grinding wheel grinding depth and grinding fluid flow rate, the workpiece rotation speed is 100-2000rpm, the grinding wheel rotation speed is 500-3000rpm, the workpiece feed speed is 0.1-1mm / min, the grinding wheel grinding depth is 0.5-5μm, and the grinding fluid flow rate is 10-100mL / h.

[0052] The wafer surface obtained by the chemical mechanical grinding process has no microcracks and breakage, and the surface roughness is S aLess than 2.0nm, no subsurface crack damage, and the thickness of the damaged layer is less than 200nm.

[0053] Furthermore, the specific operation steps of preparing the oil-based thermally active-photoactive composite grinding fluid in step S1 include:

[0054] S11, pouring polyethylene glycol, glycerol and vegetable oil into a beaker in sequence, mechanically mixing and stirring for 5 to 10 minutes to obtain a polyethylene glycol-glycerol mixed oil solution;

[0055] S12. According to the material composition and chemical bond type of the hard and brittle semiconductor material, the corresponding organic thermal decomposition type oxidant and organic photodecomposition type oxidant are selected to prepare a thermally active and photoactive oxidant complex, and the thermally active-photoactive oxidant complex is added to the polyethylene glycol-propylene glycol mixed oil solution. The thermally active-photoactive oxidant complex is dissolved in the polyethylene glycol-propylene glycol mixed oil solution by heating and stirring in a water bath for 10 to 20 minutes to obtain an oil-based thermally active-photoactive composite grinding fluid, as shown in Figures 2(a), 2(b), and 2(c).

[0056] S13. According to the actual processing conditions, an oil-based thermally active-photoactive composite grinding fluid is selected to carry out a free radical controlled oxidation reaction on the wafer surface material.

[0057] Preferably, the organic thermal decomposition type oxidant refers to an organic thermal decomposition type oxidant that is soluble in an oily solvent and decomposes by heat to produce free radicals to carry out a controlled free radical oxidation reaction on hard and brittle semiconductor materials under the action of mechanical force, mainly including azobiscyanovaleric acid (ACVA), azobisisobutyric acid (AIBME) or azobisisobutylamidine dihydrochloride (AIBA); the organic photodecomposition type oxidant refers to an organic photodecomposition type oxidant that is soluble in an oily solvent and decomposes by ultraviolet light to produce free radicals to carry out a controlled free radical oxidation reaction on hard and brittle semiconductor materials under the action of mechanical force, mainly including hydroxyacetophenone (2959), trimethylbenzoyl phenylphosphonate (TPO) or trimethylbenzoyl (819). The thermally active-photoactive oxidant compound contains at least one thermally active oxidant and one photoactive oxidant or multiple thermally active and photoactive oxidants, the mass percentage of the thermally active oxidant to the photoactive oxidant is between 10:1 and 1:10, and the mass percentage of the thermally active-photoactive oxidant compound is between 1.0% and 10.0%. The mass percentage of polyethylene glycol and glycerol is between 10% and 20%. The base liquid vegetable oil is one or more of castor oil, olive oil, soybean oil, and rapeseed oil.

[0058] The main working principle of the oil-based thermally active-photoactive composite grinding fluid: Grinding heat and ultraviolet radiation can induce the decomposition of thermally decomposable and photodecomposable organic oxidants in the oil-based thermally active-photoactive composite grinding fluid to produce active free radicals, which quickly undergo free radical oxidation reactions on hard and brittle semiconductor materials under mechanical force, and promote the formation of an oxide layer with low hardness and low interface bonding strength on the wafer surface; the diamond abrasive grinding wheel mechanically removes the oxide layer on the wafer surface, and the oxide layer with low hardness and low bonding strength is broken and peeled off in layers, and the rapidly exposed new surface is further oxidized and removed, thereby obtaining high processing efficiency; polyethylene glycol and propylene glycol are used to synergistically regulate the grinding heat in the grinding processing area, inhibit thermal damage to the wafer, and regulate the decomposition rate of the thermally decomposable oxidant; vegetable oil is used to regulate the contact stress between the diamond abrasive and the oxide layer, thereby achieving high-efficiency, low-damage ultra-precision grinding of hard and brittle semiconductor materials that are difficult to process.

[0059] Furthermore, the specific operation steps of the chemical mechanical grinding system constructed in step S2 include:

[0060] S21. Ultra-precision machine tools are placed in a room with yellow light without ultraviolet rays;

[0061] S22. An ultraviolet light generator with adjustable irradiation intensity and wavelength is provided inside the ultraprecision machine tool. The ultraviolet light generator is placed at the upper left of the wafer and grinding wheel grinding area through a multi-degree-of-freedom fixture, and the distance from the wafer to be processed is 2 to 5 cm;

[0062] S23, the semiconductor wafer to be processed is clamped onto the workbench connected to the left high-speed air-floating spindle by vacuum adsorption, and the diamond abrasive wheel with micron or submicron particle size is fixed to the right high-speed air-floating spindle by a fixture;

[0063] S24, the oil-based thermally active-photoactive composite grinding fluid is atomized into small droplets with a certain speed by compressed air with the aid of a micro-lubrication device and sprayed onto the surface of the wafer to be processed;

[0064] Specifically, the power of the ultraviolet light generator is between 50 and 200 W, the ultraviolet light band is between 100 and 400 nm, the diamond abrasive grinding wheel is a metal bond or a ceramic bond diamond grinding wheel, and the diamond particle size is 0.5 to 10.0 μm, as shown in FIG. 2( a ), FIG. 2( b ), and FIG. 2( c ).

[0065] Furthermore, the specific operation steps of grinding the workpiece in step S3 include:

[0066] S31, start the high-speed air-floating spindle on the right side of the machine tool to drive the diamond abrasive grinding wheel to rotate, start the high-speed air-floating spindle on the left side of the machine tool to drive the wafer to rotate, start the micro-lubrication device inside the machine tool to atomize the oil-based thermal-active-photoactive composite grinding fluid into small droplets according to a certain amount and then spray it onto the semiconductor wafer, and start the linear motors in the X direction and Z direction at the same time, then apply the feed amount in the X direction and the grinding depth in the Z direction, and finally control the diamond grinding wheel and the wafer to rotate relative to each other for grinding;

[0067] S32. Adjust the ultraviolet light generator, and use the grinding heat energy and ultraviolet light radiation energy to induce the decomposition of organic thermal decomposition type and photodecomposition type oxidants in the oil-based thermally active-photoactive composite grinding fluid to produce active free radicals, which react with the wafer surface material under mechanical stress to form an oxide layer with low interface bonding strength.

[0068] Specifically, the equations for the decomposition of the organic thermal decomposition type oxidant azobiscyanovaleric acid (ACVA) and the organic photodecomposition type oxidant hydroxyacetophenone (2959) by grinding heat and ultraviolet radiation are as follows:

[0069]

[0070] The chemical reaction equation for the formation of the oxide layer on the wafer surface is as follows:

[0071] M+HOCOCH2CH2C(CH3)(CN)·=HOCOCH2CH2C(CH3)(CN)M

[0072] M+·NC(CH3)(CN)CH2CH2COOH=MNC(CH3)(CN)CH2CH2COOH

[0073] M+HOCH2CH2OC6H4CO·=HOCH2CH2OC6H4COM

[0074] M+·C(CH3)2OH=MC(CH3)2OH

[0075] Among them, M is a hard and brittle semiconductor material.

[0076] Based on step S3, the oxide layer on the surface of the wafer is removed by grinding. The critical grinding depth d for mechanical removal of the oxide layer by diamond abrasive is c The expression is as follows:

[0077] d c =λ(H / E) 1 / 2 (K c / H) 2

[0078] Where λ is the brittle-to-plastic transition factor of the hard-brittle semiconductor material, H is the hardness of the oxide layer on the wafer surface, E is the elastic modulus of the oxide layer on the wafer surface, and K c is the fracture toughness of the oxide layer on the wafer surface;

[0079] S33, using white light interferometer to measure the surface roughness S of the wafer after grinding a The surface of the workpiece after grinding was observed using a field emission scanning electron microscope, and the damage type and scale of the wafer subsurface after grinding were observed using a focused ion beam-transmission electron microscope.

[0080] The ultra-precision chemical mechanical grinding method of hard and brittle semiconductor wafers and the thermally active-photoactive composite grinding fluid of the present invention are further described in conjunction with the embodiments:

[0081] In this embodiment, a 2-inch hard and brittle gallium nitride wafer is selected as the workpiece for processing, and an ultra-precision machine tool customized by the laboratory is used as the test platform. The ultraviolet light generator can stably irradiate the wafer to be processed and the thermally active-photoactive composite grinding droplets on the wafer surface. The metal bond diamond abrasive wheel with an average particle size of 1 μm is used to grind the above wafer, as shown in Figure 2 (a), Figure 2 (b), and Figure 2 (c), for chemical mechanical grinding. After grinding, the sample is ultrasonically cleaned with alcohol for 10 minutes. The surface roughness S of the wafer after grinding is measured using a white light interferometer. a , measuring range 50μm×50μm, using field emission scanning electron microscopy to observe the surface of the ground wafer, and using transmission electron microscopy combined with focused ion beam sampling technology to observe the sub-surface of the ground wafer.

[0082] The specific implementation steps are as follows:

[0083] S1. Based on the chemical principle that organic thermal decomposition type oxidants interact with heat to produce free radical active species, the chemical principle that organic photodecomposition type oxidants interact with ultraviolet light to produce free radical active species, and the free radical reaction principle that free radical active species react with inert materials to form an oxide layer, in view of the characteristics of hard and brittle semiconductor materials, such as high hardness, great brittleness, and stable chemical properties, a thermally active-photoactive grinding fluid is configured that can produce free radical active species under the action of grinding heat energy and ultraviolet radiation energy and can carry out controllable free radical oxidation reaction on workpiece materials under mechanical stress:

[0084] S11. In a chemical experiment operation box, a certain amount of polyethylene glycol, glycerol and vegetable oil are poured into a beaker in sequence, and mechanically mixed and stirred for 5 to 10 minutes to obtain a polyethylene glycol-glycerol mixed oil solution;

[0085] S12, slowly adding a certain amount of organic thermal decomposition type oxidant and photodecomposition type oxidant complex to the polyethylene glycol-glycerol mixed oil solution, heating and stirring in a water bath for 10 to 20 minutes, dissolving the thermally active-photoactive oxidant complex into the polyethylene glycol-glycerol mixed oil solution, and obtaining an oil-based thermally active-photoactive composite grinding fluid;

[0086] S13, pour the prepared thermally active-photoactive grinding fluid into a light-proof reagent bottle for later use.

[0087] S2. Build a UV-diamond abrasive wheel chemical mechanical grinding platform with UV irradiation function and adjustable and controllable irradiation emphasis and UV wavelength:

[0088] S21, fix the ultraviolet light generator 3 cm away from the contact interface between the wafer and the grinding wheel. The ultraviolet light generator can rotate and move to focus the ultraviolet light on a designated area;

[0089] S22, clamping the wafer onto a workbench connected to the left high-speed air-floating spindle by vacuum adsorption, and fixing a 1 μm-sized metal-bonded diamond abrasive grinding wheel onto the right high-speed air-floating spindle;

[0090] S23, with the help of the micro-lubrication device inside the machine tool, the thermally active-photoactive composite grinding fluid configured in S1 is atomized into small droplets at a certain flow rate and sprayed onto the surface of the processed wafer.

[0091] S3. According to the composition, content and flow rate of the oxidant compound in the thermal-photoactive composite grinding fluid obtained in S1, as well as the hardness, elastic modulus, fracture toughness and interface separation strength of the oxide layer of the workpiece material, the power and band of the ultraviolet light generator, the rotation speed of the workpiece, the rotation speed of the grinding wheel and the feed speed of the workpiece, the grinding depth of the grinding wheel and the flow rate of the grinding fluid are set. The selection of process parameters is based on the mechanical properties of the oxide layer on the surface of the wafer, and the ultra-precision chemical mechanical grinding platform is started to carry out the free radical oxidation reaction of the thermal-photoactive composite grinding fluid of the hard and brittle semiconductor material, the dynamic removal of the surface oxide layer by diamond abrasive micro-cutting with small load and high efficiency, and the mechanical chemical grinding of the material:

[0092] S31, start the high-speed air-floating spindle on the right side of the machine tool to drive the diamond abrasive grinding wheel to rotate, start the high-speed air-floating spindle on the left side of the machine tool to drive the wafer to rotate, start the micro-lubrication device inside the machine tool to atomize the oil-based thermal-active-photoactive composite grinding fluid into small droplets according to a certain amount and then spray it onto the semiconductor wafer, and start the linear motors in the X direction and Z direction at the same time, then apply the feed amount in the X direction and the grinding depth in the Z direction, and finally control the diamond grinding wheel and the wafer to rotate relative to each other for grinding;

[0093] S32, turning on the ultraviolet light generator, adjusting the power and band switch, using the grinding heat energy and ultraviolet light irradiation energy to induce the decomposition of the thermally decomposable and photodecomposable organic oxidants in the oil-based thermally active-photoactive composite grinding fluid to generate active free radicals to carry out free radical oxidation reaction on the surface material of the wafer under mechanical stress, forming an oxide layer with low interface bonding strength, and then carrying out the mechanochemical grinding process of the workpiece material by free radical oxidation reaction of the thermally active-photoactive composite grinding fluid, and the dynamic removal of the surface oxide layer by micro-cutting with diamond abrasives with small load and high efficiency;

[0094] S33. After 50 to 60 minutes, the test machine is turned off, the wafer is removed, and then the wafer is cleaned with alcohol ultrasonic for 10 minutes. The surface roughness S of the ground wafer is measured using a white light interferometer. a The measurement range is 50μm×50μm. The surface of the workpiece after grinding is observed using a field emission scanning electron microscope, and the damage type and scale of the wafer subsurface after grinding are observed using a focused ion beam-transmission electron microscope.

[0095] Furthermore, the present invention designs two grinding fluids and three groups of different grinding process tests to verify the advantages of the chemical mechanical grinding method based on the oil-based thermal-active-photoactive grinding fluid. The specific contents are as follows: Specific embodiment 1:

[0097] Grinding fluid: Grinding fluid A (30% polyethylene glycol, 10% glycerol, 60% castor oil) and Grinding fluid B (30% polyethylene glycol, 10% glycerol, 55% castor oil, 2% azobiscyanovaleric acid (ACVA), 3% hydroxyacetophenone (2959)).

[0098] Grinding process: Grinding process A (grinding fluid A, grinding fluid flow rate 30 mL / h, abrasive particle size 1 μm, workpiece speed 199 rpm, grinding wheel speed 2000 rpm, workpiece feed speed 0.5 mm / min, grinding wheel grinding depth 1 μm, grinding time 60 min, UV generator power 60 W, band 365 nm), Grinding process B (grinding fluid B, grinding fluid flow rate 30 mL / h, abrasive particle size 1 μm, workpiece speed 199 rpm, grinding wheel speed 2 000rpm, workpiece feed speed 0.5mm / min, grinding wheel grinding depth 1μm, grinding time 60min, UV generator off) and grinding process C (grinding fluid B, grinding fluid flow 30mL / h, abrasive particle size 1μm, workpiece speed 199rpm, grinding wheel speed 2000rpm, workpiece feed speed 0.5mm / min, grinding wheel grinding depth 1μm, grinding time 60min, UV generator on power 60W, band 365nm).

[0099] The test results are shown in Figures 3(a), 3(b), 3(c), 3(d), 3(e), and 3(f). The surface roughness S of the GaN wafers ground by grinding fluid A and grinding process A is a =9.4±0.7nm, the wafer surface shows obvious grinding scratches and micro-cracks. Surface roughness S of GaN wafer ground by grinding fluid B-grinding process B a =8.4±1.5nm, the wafer surface shows obvious grinding scratches and micro-cracks. Surface roughness S of the GaN wafer ground by grinding fluid B-grinding process C a =1.5±0.7nm, and there are no obvious grinding scratches and micro-cracks on the wafer surface. The analysis of the subsurface damage layer in Figure 4(a) and Figure 4(b) further proves that the UV-irradiated chemical mechanical grinding process based on the oil-based thermal-active-photoactive composite grinding fluid (grinding process C) can effectively inhibit the formation of subsurface microcracks on the GaN wafer and reduce the thickness of the subsurface damage layer, while the traditional vegetable oil mechanical grinding process (grinding process A) has microcracks on the subsurface and severe crystal plane slip, and the thickness of the damage layer is as high as 500nm.

[0100] By comparing the processing effects of mechanical grinding of diamond abrasive wheels with vegetable oil-based liquid and chemical mechanical grinding with oil-based thermal-photoactive composite grinding fluid, it is found that the processing effect of the chemical mechanical grinding method of the present invention is significantly better than the traditional mechanical grinding method. In particular, experiment B uses a thermal-photoactive composite grinding fluid, but the ultraviolet light generator is not turned on during the processing, and only the thermal decomposition type oxidant in the grinding fluid is affected by the grinding heat energy to produce a single activated carbon free radical, so the oxidation effect is weak. However, in experimental group C, because the ultraviolet light generator is turned on, the thermal decomposition type oxidant and the photodecomposition type oxidant are both cracked during the grinding process to produce a variety of activated carbon free radicals and carboxyl free radicals. The synergistic effect of each active free radical greatly increases the degree of oxidation of the surface material of the wafer, which is conducive to the formation of a thicker oxide layer on the surface of the wafer, thereby improving the removal of the material and obtaining better grinding performance.

[0101] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A chemical mechanical grinding system for hard and brittle semiconductor wafers, characterized in that: The machine tool body is provided with a first linear drive device and a second linear drive device, wherein the first linear drive device enables the first high-speed air-floating spindle to move in the X direction, and the second linear drive device enables the second high-speed air-floating spindle to move in the Z direction, wherein the first high-speed air-floating spindle drives the semiconductor wafer to rotate; the second high-speed air-floating spindle drives the diamond abrasive grinding wheel to rotate; an ultraviolet light generator and a micro-lubrication device are arranged on the outer side of the semiconductor wafer; the micro-lubrication device atomizes the oil-based thermal-active-photoactive composite grinding fluid into small droplets according to a certain amount and then sprays them onto the semiconductor wafer; the ultraviolet light generator emits ultraviolet light, and the grinding heat energy and ultraviolet light irradiation energy induce the organic thermal decomposition type and photodecomposition type oxidant in the oil-based thermal-active-photoactive composite grinding fluid to decompose and generate active free radicals to carry out free radical oxidation reaction on the surface material of the wafer under the action of mechanical stress, thereby forming an oxide layer with low interface bonding strength.

2. A method for chemical mechanical grinding of hard and brittle semiconductor wafers using the chemical mechanical grinding system for hard and brittle semiconductor wafers according to claim 1, characterized in that: as follows: S1, the second high-speed air-floating spindle drives the diamond abrasive grinding wheel to rotate, the first high-speed air-floating spindle drives the wafer to rotate, the micro-lubrication device atomizes the oil-based thermal-active-photoactive composite grinding fluid into small droplets according to a certain amount and sprays them onto the semiconductor wafer, and at the same time, the first linear drive device and the second linear drive device apply the feed amount in the X direction and the grinding depth in the Z direction, and finally control the diamond grinding wheel and the wafer to rotate relative to each other for grinding; S2. Adjust the ultraviolet light generator, and use the grinding heat and ultraviolet radiation to induce the decomposition of organic thermal decomposition type and photodecomposition type oxidants in the oil-based thermally active-photoactive composite grinding fluid to produce active free radicals, which react with the wafer surface material under mechanical stress to form an oxide layer with low interface bonding strength; based on step S1, grind away the oxide layer on the wafer surface.

3. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 2, characterized in that: as follows: Critical grinding depth d for mechanical removal of oxide layer by diamond abrasive c The expression is as follows: d c λ(H / E) 1 / 2 (K c / H) 2 Where λ is the brittle-to-plastic transition factor of the hard-brittle semiconductor material, H is the hardness of the oxide layer on the wafer surface, E is the elastic modulus of the oxide layer on the wafer surface, and K c It is the fracture toughness of the oxide layer on the wafer surface.

4. The method for grinding a hard and brittle semiconductor wafer according to claim 2, characterized in that: as follows: After step S2 is completed, the surface roughness S of the ground wafer is measured using a white light interferometer. a The surface of the workpiece after grinding was observed using a field emission scanning electron microscope, and the damage type and scale of the wafer subsurface after grinding were observed using a focused ion beam-transmission electron microscope.

5. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 2, characterized in that: The power of the ultraviolet light generator is 50-200W, the ultraviolet light waveband is in the range of 100-400nm, the diamond abrasive grinding wheel is a metal bond or a ceramic bond diamond grinding wheel, and the diamond particle size is 0.5-10.0μm.

6. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 2, characterized in that: The rotation speed of the semiconductor wafer is 100 to 2000 rpm, the rotation speed of the grinding wheel is 500 to 3000 rpm, the feed speed of the semiconductor wafer is 0.1 to 1 mm / min, the grinding depth of the grinding wheel is 0.5 to 5 μm, and the grinding fluid flow rate is 10 to 100 mL / h.

7. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 2, characterized in that: The grinding heat and ultraviolet radiation can induce the decomposition of organic thermal decomposition type and photodecomposition type oxidants in the oil-based thermally active-photoactive composite grinding fluid to produce thermochemical and photochemical reactions of active carbon free radicals and carboxyl free radicals as follows: The chemical reaction equation for the formation of the oxide layer on the wafer surface is as follows: M+HOCOCH2CH2C(CH3)(CN)·=HOCOCH2CH2C(CH3)(CN)M M+·NC(CH3)(CN)CH2CH2COOH=MNC(CH3)(CN)CH2CH2COOH M+HOCH2CH2OC6H4CO·=HOCH2CH2OC6H4COM M+·C(CH3)2OH=MC(CH3)2OH Among them, M is a hard and brittle semiconductor material.

8. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 2, characterized in that: The steps for preparing the oil-based thermally active-photoactive composite grinding fluid are as follows: S1, mixing polyethylene glycol, glycerol and vegetable oil and stirring to obtain a polyethylene glycol-glycerol mixed oil solution; S2. According to the material composition and chemical bond type of the hard and brittle semiconductor material, the corresponding organic thermal decomposition type oxidant and organic photodecomposition type oxidant are selected to prepare a thermally active and photoactive oxidant complex, and the active-photoactive oxidant complex is added to a polyethylene glycol-propylene glycol mixed oil solution, and the complex is heated and stirred in a water bath to dissolve into the polyethylene glycol-propylene glycol mixed oil solution to obtain an oil-based thermally active-photoactive composite grinding fluid.

9. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 8, characterized in that: The organic thermal decomposition type oxidant is azobiscyanovaleric acid, azobisisobutyric acid or azobisisobutylamidine dihydrochloride; the organic photodecomposition type oxidant is hydroxyacetophenone, trimethylbenzoylphenylphosphonate or trimethylbenzoyl, The thermally active-photoactive oxidant compound contains at least one thermally active oxidant and one photoactive oxidant or multiple thermally active and photoactive oxidants, the mass percentage of the thermally active oxidant to the photoactive oxidant is between 10:1 and 1:10, and the mass percentage of the thermally active-photoactive oxidant compound is between 1.0% and 10.0%.

10. The method for chemical mechanical grinding of a hard and brittle semiconductor wafer according to claim 8, characterized in that: The polyethylene glycol and glycerol are used to adjust the viscosity and cooling performance of the grinding fluid, and the mass percentage is between 10% and 20%; the vegetable oil is one or more of castor oil, olive oil, soybean oil, and rapeseed oil, which is used as a base fluid to dissolve organic thermally active and photoactive oxidants and adjust the lubrication performance of the grinding fluid.

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