Diamond polishing method based on plasma etching and modification effects

Abstract

Provided is a diamond polishing method based on plasma etching and modification effects. The method comprises: (S101) using a fixture (1) to place a diamond (2) to be polished above a rigid polishing disc (3), wherein a plurality of through holes (4) running through in the up-down direction are formed in the rigid polishing disc (3); (S102) controlling said diamond (2) and the rigid polishing disc (3) to rotate in opposite directions; (S103) heating said diamond (2) with an atmospheric inductively coupled plasma (5) containing an oxygen radical and a hydroxyl radical; and (S104) when heating is performed until the instantaneous temperature exceeds a critical transition temperature corresponding to differential etching of atoms on the surface, generating atom-selective etching and modification effects, so as to complete polishing of said diamond (2). By using the atmospheric inductively coupled plasma (5) containing a high-concentration and highly-activity oxygen radical and hydroxyl radical, and by combining atom-selective etching removal and hydroxyl-modified polishing removal, planarization on the surface of said diamond (2) is achieved, thereby simplifying a polishing apparatus while improving polishing efficiency of said diamond (2).

Description

A diamond polishing method based on plasma etching and modification Technical Field

[0001] The invention relates to the technical field of diamond polishing, in particular to a diamond polishing method based on plasma etching and modification. Background Art

[0002] Single-crystal diamond's unique crystal structure and strong carbon-carbon bonds give it extreme chemical inertness and excellent physical properties, making it a key foundational material in modern industry. The rapid development of microwave plasma chemical vapor deposition technology has also enabled the mass production of large-scale, high-quality synthetic diamonds, breaking through the price, quantity, and size limitations of traditional natural diamonds and enabling the widespread application of diamond in high-tech fields such as optics, thermal engineering, and semiconductors. Furthermore, due to its ultra-high hardness, chemical inertness, and biocompatibility, single-crystal diamond is often used in single-point diamond cutting tools for ultra-precision lathes and in bio-implantable devices, possessing extremely high application value.

[0003] A diamond surface with low damage, ultra-smoothness and high precision is the prerequisite for achieving various excellent properties of diamond. However, as a typical difficult-to-process material, diamond's extremely high hardness and strong chemical stability severely limit its flattening processing, becoming one of the key issues restricting the industrial application of wafer-level single-crystal diamond.

[0004] Most existing diamond polishing methods use capacitively coupled plasma as the plasma source, which makes it difficult to produce higher concentrations of hydroxyl active particles, resulting in low polishing efficiency. In addition, the excitation method of capacitively coupled plasma requires the use of a vacuum chamber to confine the reaction gas, resulting in complex processing equipment and high costs.

[0005] Summary of the Invention

[0006] In view of this, the present invention proposes a diamond polishing method based on plasma etching and modification, the specific scheme is as follows:

[0007] A diamond polishing method based on plasma etching and modification, comprising:

[0008] The diamond to be polished is placed on a rigid polishing disc through a fixture; the rigid polishing disc is provided with a plurality of through holes extending from top to bottom;

[0009] The diamond is controlled to rotate in a first direction and the rigid polishing disc is controlled to rotate in a second direction by the fixture; the first direction is opposite to the second direction;

[0010] spraying atmospheric inductively coupled plasma containing oxygen free radicals and hydroxyl free radicals above the rigid polishing disk, so that the atmospheric inductively coupled plasma passes through the through hole to heat the diamond;

[0011] When the instantaneous temperature is heated to a temperature exceeding the critical transition temperature corresponding to the differential etching of surface atoms, the diamond is subjected to atomic selective etching by oxygen free radicals in the atmospheric inductively coupled plasma, and at the same time, the diamond is modified by hydroxyl free radicals in the atmospheric inductively coupled plasma to complete the polishing of the diamond.

[0012] In a specific embodiment, the method further includes: controlling the diamond to reciprocate at a preset speed along the radial direction of the rigid polishing disk by the fixture.

[0013] In a specific embodiment, the fixture includes a rotation control part and a reciprocating control part, the rotation control part controls the diamond to rotate in the first direction, and the reciprocating control part controls the diamond to perform the reciprocating motion at the preset speed along the radial direction of the rigid polishing disk.

[0014] In a specific embodiment, multiple through holes are evenly arranged above the rigid polishing disk; the through holes at the same distance from the center of the rigid polishing disk are connected by flow channels; and the multiple through holes located in the same radial direction on the rigid polishing disk are connected by radial grooves.

[0015] In one embodiment, the atmospheric inductively coupled plasma is ejected through a torch body;

[0016] The torch body includes an inner torch tube and an outer torch tube;

[0017] The torch body ejects the atmospheric inductively coupled plasma through the outer torch tube and / or the inner torch tube;

[0018] When the atmospheric inductively coupled plasma is ejected, a mixed gas is introduced into the inner torch tube as an excitation gas to generate active free radicals, and argon gas is introduced into the outer torch tube as a cooling gas.

[0019] In a specific embodiment, the atmospheric inductively coupled plasma is obtained by a mixture of reaction liquid evaporation / volatile gas, oxygen and argon.

[0020] In a specific embodiment, the flow rate of each of the gases used to generate the atmospheric inductively coupled plasma is controlled by a flow meter; different gases are corresponding to different flow meters;

[0021] The mixed gas is controlled by a spark generator and a radio frequency coil to generate the atmospheric inductively coupled plasma.

[0022] In a specific embodiment, it also includes:

[0023] The reaction rate of the atomic selective etching is controlled by controlling the flow rate of the oxygen gas. The greater the flow rate of the oxygen gas, the faster the reaction rate of the atomic selective etching.

[0024] In a specific embodiment, the atmospheric inductively coupled plasma penetrates the through hole and irradiates the surface of the diamond sample for a time ranging from 8 minutes to 12 minutes.

[0025] In a specific embodiment, the critical transition temperature ranges from 1250°C to 1300°C. Beneficial effects:

[0026] The present invention selects an atmospheric inductively coupled plasma containing high-concentration and highly active oxygen free radicals and hydroxyl free radicals as the plasma source in the diamond polishing method based on plasma etching and modification. The diamond surface is flattened by combining atomic selective etching removal and hydroxyl modified polishing removal. While improving the polishing efficiency of the diamond, the polishing device is simplified, the polishing cost is reduced, and the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a flow chart of a diamond polishing method based on plasma etching and modification according to an embodiment of the present invention;

[0028] FIG2 is a schematic diagram of a diamond polishing method based on plasma etching and modification according to an embodiment of the present invention;

[0029] FIG3 is a schematic diagram of a diamond polishing device according to an embodiment of the present invention;

[0030] FIG4 is a schematic diagram showing the relationship between oxygen flow rate, instantaneous temperature, and material removal rate according to an embodiment of the present invention;

[0031] FIG5 is a schematic diagram of etching phenomena of different types of plasma according to an embodiment of the present invention;

[0032] FIG6 is a schematic diagram of characteristic spectra excited by different types of plasmas according to an embodiment of the present invention;

[0033] FIG7 is a schematic diagram showing the relationship between the instantaneous temperature of the diamond surface, the RF power, and the surface roughness according to an embodiment of the present invention;

[0034] FIG8 is a schematic diagram of a characteristic spectrum excited by a plasma containing a reaction liquid according to an embodiment of the present invention;

[0035] FIG9 is a schematic diagram showing the intensity of hydroxyl active species in a plasma containing a reaction solution under different RF power sources according to an embodiment of the present invention.

[0036] Figure numerals: 1- fixture; 2- diamond; 3- rigid polishing disk; 4- through hole; 5- atmospheric inductively coupled plasma; 6- flow channel; 7- radial groove; 8- torch body; 81- inner torch tube; 82- outer torch tube; 9- flow meter; 10- spark generator; 11- radio frequency coil. DETAILED DESCRIPTION

[0037] Hereinafter, various embodiments of the present disclosure will be described more fully. The present disclosure may have various embodiments, and modifications and variations may be made therein. However, it should be understood that there is no intention to limit the various embodiments of the present disclosure to the specific embodiments disclosed herein, but rather that the present disclosure should be construed to encompass all modifications, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of the present disclosure.

[0038] The terms used in the various embodiments disclosed in the present invention are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments disclosed in the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise specified, all terms used herein (including technical terms and scientific terms) have the same meaning as those generally understood by those skilled in the art of the various embodiments disclosed in the present invention. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly specified in the various embodiments disclosed in the present invention.

[0039] Example 1

[0040] The present invention uses an atmospheric inductively coupled plasma (ICP) containing high concentrations of highly active oxygen and hydroxyl radicals as the plasma source in a diamond polishing method based on plasma etching and modification. This combines atomically selective etching and hydroxyl modification polishing to achieve diamond surface flattening. This improves diamond polishing efficiency while simplifying the polishing apparatus, reducing polishing costs and improving production efficiency. The specific process is shown in Figure 1 of the specification. The specific scheme is as follows:

[0041] The method mentioned in this embodiment is a diamond polishing method based on plasma etching and modification, as shown in Figures 1 to 3, comprising:

[0042] 101. The diamond 2 to be polished is placed on a rigid polishing plate 3 by a fixture 1; the rigid polishing plate 3 is provided with a plurality of through holes 4 extending from top to bottom;

[0043] 102. The diamond 2 is controlled to rotate in a first direction and the rigid polishing disc 3 is controlled to rotate in a second direction by the fixture 1; the first direction is opposite to the second direction;

[0044] 103. Spraying atmospheric inductively coupled plasma 5 containing oxygen free radicals and hydroxyl free radicals above the rigid polishing pad 3, so that the atmospheric inductively coupled plasma 5 passes through the through hole 4 to heat the diamond 2;

[0045] 104. When the instantaneous temperature is heated to a temperature exceeding the critical transition temperature corresponding to the differential etching of surface atoms, the diamond 2 is atomically selectively etched by oxygen free radicals in the atmospheric inductively coupled plasma 5, and at the same time, the diamond 2 is modified by hydroxyl free radicals in the atmospheric inductively coupled plasma 5, thereby completing the polishing of the diamond 2.

[0046] The diamond polishing method of this embodiment is applicable to a variety of fields, including but not limited to glass production, semiconductor manufacturing, and high-precision machining. For example, in glass factories, semiconductor production lines, or high-precision machine tools, the diamond polishing method of this embodiment can be applied to the manufacturing process to provide higher-quality and more precise products.

[0047] 101. The diamond 2 to be polished is placed on a rigid polishing disc 3 by means of a fixture 1; the rigid polishing disc 3 is provided with a plurality of through holes 4 extending from top to bottom.

[0048] The diamond polishing method mentioned in this embodiment is an efficient and precise processing technology that can be widely used in the manufacturing process of diamond products. In this diamond polishing method, the use of the clamp 1 plays a key role. It can stably fix the diamond 2 to be polished and ensure its correct position. By placing the diamond 2 above the rigid polishing disk 3, the subsequent polishing process can be made more convenient and accurate. The through hole 4 that runs through the upper and lower parts of the rigid polishing disk 3 is for introducing atmospheric inductively coupled plasma 5. This plasma 5 contains oxygen free radicals and hydroxyl free radicals, which pass through the rigid polishing disk 3 through the through hole 4 and heat the surface of the diamond 2 to achieve atomic selective etching and modification of the diamond 2.

[0049] 102. The diamond 2 is controlled to rotate in a first direction and the rigid polishing disc 3 is controlled to rotate in a second direction by the fixture 1; the first direction is opposite to the second direction.

[0050] Diamond 2 is rotated in a first direction by means of a clamp 1. Clamp 1 stably secures diamond 2 and ensures it maintains the correct position and angle during rotation. This rotation ensures that every area of ​​diamond 2's surface comes into contact with polishing disc 3 evenly, resulting in an overall uniform polishing effect.

[0051] Simultaneously, during the polishing process, the rigid polishing disk 3 is controlled to rotate in a second direction. This rotation, opposite to the rotation of the diamond 2, helps generate a mechanical shear force, achieving uniform polishing of the surface of the diamond 2. In this embodiment, the fixture 1 controls the clockwise rotation of the diamond 2, while the rigid polishing disk 3 rotates counterclockwise. This opposing rotational direction generates a transverse shear force between the surface of the diamond 2 and the rigid polishing disk 3. This transverse shear force removes surface irregularities and imperfections, and improves surface flatness and finish.

[0052] By controlling the diamond 2 and the rigid polishing disc 3 to rotate in opposite directions through the fixture 1, defects and uneven parts on the surface of the diamond 2 can be removed more evenly, making the surface more flat and smooth.

[0053] 103. Spray atmospheric inductively coupled plasma 5 containing oxygen free radicals and hydroxyl free radicals above the rigid polishing pad 3, so that the atmospheric inductively coupled plasma 5 passes through the through hole 4 to heat the diamond 2.

[0054] Atmospheric inductively coupled plasma 5 containing oxygen free radicals and hydroxyl free radicals penetrates through hole 4 on rigid polishing disk 3 and contacts the surface of diamond 2 to heat diamond 2 to achieve atomic selective etching and modification of diamond 2 .

[0055] During the polishing process, atmospheric inductively coupled plasma 5 is ejected, and the oxygen radicals in it produce different etching priorities based on the number of dangling bonds of carbon atoms at different locations on the diamond 2 surface. This is known as atomically selective etching. This process eliminates the differential bonding of carbon atoms in the etched areas of the diamond 2 surface, removing subsurface damage and amorphous layers, and creating an atomically smooth surface (roughness Sa less than 0.5nm).

[0056] At the same time, highly active hydroxyl radicals attach to diamond 2 and the rigid polishing pad 3, forming bonds with carbon atoms in diamond 2 and specific atoms in the rigid polishing pad 3, resulting in a modification effect. A hydroxyl dehydration condensation reaction (CD-OH+M-OH→CD-O-M+H2O) then occurs at the interface between the two (CD refers to the carbon atoms on the diamond surface modified with hydroxyl groups, and M refers to the atoms on the polishing pad surface modified with hydroxyl groups). This forms a new bond, CD-OM, at the interface. Mechanical shear fractures the C-CD bond on the diamond surface, resulting in impurity removal from the surface of diamond 2. Because the raised areas on the surface of diamond 2 are more susceptible to capturing hydroxyl radicals, resulting in a higher material removal rate, its surface flatness eventually approaches that of the rigid polishing pad 3, achieving global flattening of diamond 2 (flatness less than 0.5μm).

[0057] After the polishing process of the above steps, the surface of the diamond 2 is fully trimmed and improved. This method not only removes surface defects and impurities, but also improves the overall quality and performance of the diamond 2. Therefore, this polishing method has important application value in the manufacturing process of diamond products.

[0058] 104. When the instantaneous temperature is heated to a temperature exceeding the critical transition temperature corresponding to the differential etching of surface atoms, the diamond 2 is atomically selectively etched by oxygen free radicals in the atmospheric inductively coupled plasma 5, and at the same time, the diamond 2 is modified by hydroxyl free radicals in the atmospheric inductively coupled plasma 5, thereby completing the polishing of the diamond 2.

[0059] When diamond 2 is heated above the critical transition temperature corresponding to differential etching of surface atoms, oxygen and hydroxyl radicals released from atmospheric inductively coupled plasma 5 begin to act, completing the polishing of diamond 2. In this embodiment, the critical transition temperature is 1270°C. (It should be noted that the instantaneous surface temperature of diamond 2 is measured using an infrared thermal imager. The measurement results are affected by many factors, including measurement distance, position, imaging focal length, and the calibrated sample emissivity. Therefore, the critical transition temperature will vary under different experimental conditions and needs to be calibrated based on the experimental results.)

[0060] First, oxygen radicals induce atomically selective etching on the surface of diamond 2. When the instantaneous temperature of the diamond surface exceeds the critical transition temperature for differential etching of surface atoms, oxygen radicals prioritize etching based on the number of dangling bonds on carbon atoms at different locations on the diamond surface. Carbon atoms with more dangling bonds are preferentially removed.

[0061] At the same time, hydroxyl radicals also modify the surface of the diamond during the heating process. Hydroxyl radicals are chemically active and can react with atoms on the diamond surface to form chemical bonds. This chemical reaction alters the surface chemical composition and structure of the diamond, resulting in improved polishing performance and surface smoothness.

[0062] Specifically, regarding the atomic selective etching mentioned in this embodiment, an etching particle screening experiment was carried out. As shown in Figures 4 to 7, a 1000W radio frequency power supply was used. The etching particle screening experiment was carried out in pure argon plasma (18slm argon cooling gas, 1.5slm argon carrier gas), oxygen-containing plasma (18slm argon cooling gas, 1.5slm argon carrier gas, 20sccm oxygen reaction gas), and fluorine-containing plasma (18slm argon cooling gas, 1.5slm argon carrier gas, 20sccm carbon tetrafluoride reaction gas). The irradiation time was 10min. During the process, the instantaneous temperature of the diamond 2 surface after stabilization was collected and its surface morphology and roughness were detected. In the etching particle screening experiment, all three different plasmas could make the diamond surface stable instantaneous temperature above 1350°C, but only the oxygen-containing plasma could reduce the diamond surface roughness from the original submicron level to 0.502nm. The unique oxygen free radicals in oxygen-containing plasma are the main reason for the atomic selective etching of the diamond surface. Other plasmas containing different free radicals cannot produce atomic selective etching and cannot achieve efficient smoothing of diamond.

[0063] Furthermore, this embodiment uses oxygen-containing plasma (gas flow rate remains unchanged) to conduct an atomic selective etching experiment to explore the critical transition temperature. The plasma irradiation time is 10 minutes. During the process, the instantaneous temperature, surface morphology and roughness of the diamond 2 surface after stabilization under different RF power supplies are collected. In the atomic selective etching experiment, as the RF power increases, the stable instantaneous temperature of the diamond 2 surface increases from 965°C to 1398°C, and different etching phenomena occur on the diamond 2 surface under different power conditions. Only when the RF power increases to 900W and the diamond surface temperature reaches 1270°C, oxygen plasma can undergo atomic selective etching reaction, effectively smoothing the diamond surface. When the instantaneous temperature increases further, the surface roughness remains stable at about 0.5nm, which still corresponds to the atomic selective etching reaction. Therefore, the critical transition temperature corresponding to the differential etching of atoms on the diamond surface is defined as 1270°C.

[0064] Furthermore, this embodiment uses a 1000W RF power supply to conduct material removal experiments under oxygen-containing plasma to explore the factors affecting the material removal rate. The plasma irradiation time is 10 minutes. During the process, the instantaneous temperature and material removal rate of the diamond 2 surface after stabilization are collected under different oxygen flow rates. In the material removal experiment, the instantaneous temperature change of the diamond surface is less than 30°C, and the effect of temperature change on the material removal rate is negligible. When the oxygen flow rate is 0, the material removal rate is 0. As the oxygen flow rate increases, the material removal rate of the diamond surface increases linearly. Within the experimental range, the material removal rate can reach up to 56.53μm / min. (It should be noted that the results of the diamond material removal rate are highly correlated with the sample size used, so the material removal rates of samples of different sizes will vary, but it always conforms to the law that the material removal rate is approximately proportional to the oxygen flow rate.)

[0065] Therefore, the highly active oxygen free radicals generated by the atmospheric inductively coupled plasma can induce atomic selective etching on the surface of diamond 2, achieving efficient ultra-smooth polishing of diamond 2. It should be noted that the generation of atomic selective etching on the surface of diamond 2 requires both high concentration of oxygen free radicals and critical transition temperature. In addition, the above critical transition temperature will shift with changes in factors such as the size of the processed diamond, the action time, and the working conditions (thermal conductivity of the sample fixture, gas flow rate, processing environment). In practical applications, it is necessary to carefully select process parameters to meet different processing requirements, and the experimental results and change trends in Figures 4 to 7 can provide a theoretical basis for the selection of process parameters.

[0066] Meanwhile, as shown in accompanying drawing 8-accompanying drawing 9, about the modification mentioned in the present embodiment, explored hydroxyl active particle induction experiment.Adopt the radio frequency power from 300-1000W, and adopt containing reaction solution (H2O2) plasma (18slm argon cooling gas, 1.5slm argon carrier gas, 20sccm containing reaction solution argon) explore hydroxyl active particle induction experiment, collect the optical excitation spectrum of plasma under different experimental conditions in the process, determine the intensity of hydroxyl active particle.In hydroxyl active particle induction experiment, raise with radio frequency power, hydroxyl active particle intensity obviously strengthens in plasma, and with power increase, enhancement amplitude rises to some extent, within the experimental interval, 900W radio frequency power can obtain the hydroxyl active particle of larger intensity, and when radio frequency power reaches 1000W, containing hydroxyl active particle intensity maximum in reaction solution plasma.This shows, under the condition of meeting atom selective etching, also can produce highly active hydroxyl radical simultaneously for hydroxyl modification.

[0067] It should be noted that the excitation intensity measured by the hydroxyl active particles is closely related to the orientation and distance of the detection probe relative to the plasma, and the active particles can be induced by substances that can ionize to produce hydroxyl groups, including but not limited to hydrogen peroxide and water vapor.

[0068] In summary, the atomically selective etching and modification of diamond 2 by oxygen and hydroxyl radicals in atmospheric inductively coupled plasma 5 allows for microscopic manipulation of the diamond 2 surface during the polishing process. This method removes defects and unevenness on the diamond 2 surface while improving its surface quality and finish. Ultimately, the diamond 2 is polished to the desired precision and quality.

[0069] In a specific embodiment, the method further includes: controlling the diamond 2 to be polished to move back and forth along the radial direction of the rigid polishing disk 3 at a preset speed through the fixture 1.

[0070] In this embodiment, in addition to the diamond 2 and the rigid polishing disk 3 rotating in opposite directions, the fixture 1 also controls the diamond 2 to be polished to reciprocate radially along the rigid polishing disk 3 at a preset speed. By controlling the movement of the diamond 2, a more uniform and comprehensive polishing effect can be achieved. During this reciprocating motion, the diamond 2 maintains sufficient contact with the rigid polishing disk 3, further enhancing the etching and modification effects. Furthermore, this reciprocating motion prevents localized overheating or overloading of the diamond 2 during the polishing process, ensuring stable and reliable polishing.

[0071] Therefore, in this embodiment, the diamond 2 to be polished is controlled by the fixture 1 to reciprocate along the radial direction of the rigid polishing disk 3 at a preset speed, which can further improve the polishing effect and make the surface of the diamond 2 more flat, smooth and precise.

[0072] In a specific embodiment, the fixture 1 includes a rotation control part and a reciprocating control part. The rotation control part controls the diamond 2 to rotate in a first direction. The reciprocating control part controls the diamond 2 to reciprocate along the radial direction of the rigid polishing disk 3 at a preset speed.

[0073] In this embodiment, the fixture 1 consists of two parts. The rotation control unit primarily controls the rotation of the diamond 2 in a first direction. The fixture 1 can adjust the rotation speed as needed to meet the polishing requirements of different materials. By controlling the rotation of the diamond 2 in the opposite direction to the rigid polishing disk 3, this helps generate a mechanical shear force, achieving uniform polishing of the surface of the diamond 2. The reciprocating control unit controls the reciprocating motion of the diamond 2 along the radial direction of the rigid polishing disk 3, thereby achieving a uniform and high-quality polishing effect.

[0074] In a specific embodiment, multiple through holes 4 are evenly arranged above the rigid polishing disk 3; the through holes 4 at the same distance from the center of the rigid polishing disk 3 are connected by the flow channel 6; and the multiple through holes 4 located in the same radial direction on the rigid polishing disk 3 are connected by the radial groove 7.

[0075] In this embodiment, a plurality of through holes 4 are evenly arranged above the rigid polishing disk 3. These through holes 4 are designed to allow the atmospheric inductively coupled plasma 5 containing oxygen free radicals and hydroxyl free radicals to penetrate the through holes 4 on the rigid polishing disk 3, contact the surface of the diamond 2, and heat the diamond 2 to achieve atomic selective etching and modification of the diamond 2.

[0076] To better control the flow and distribution of gas, through-holes equidistant from the center of the rigid polishing pad 3 are connected by flow channels 6, allowing the gas to flow evenly across the entire surface. Furthermore, radial grooves 7 are provided between multiple through-holes 4 in the same radial direction on the surface of the rigid polishing pad 3 to further enhance the flow and distribution of gas. These radial grooves 7 guide the gas from one through-hole 4 to another, thereby achieving a wide range of gas flow and distribution across the surface of the rigid polishing pad 3.

[0077] This arrangement allows for uniform gas flow and distribution between the multiple through-holes 4 on the surface of the rigid polishing disc 3, resulting in a more stable and uniform polishing process. This design also lowers surface temperature, minimizing frictional heat and thus preventing damage to materials such as diamond 2.

[0078] In one embodiment, atmospheric inductively coupled plasma 5 is ejected through the torch body 8;

[0079] The torch body 8 includes an inner torch tube 81 and an outer torch tube 82;

[0080] The torch body 8 ejects the atmospheric inductively coupled plasma 5 through the outer torch tube 82 and / or the inner torch tube 81;

[0081] When the atmospheric inductively coupled plasma 5 is ejected, a mixed gas is introduced into the inner torch tube 81 as an excitation gas to generate active free radicals, and argon gas is introduced into the outer torch tube 82 as a cooling gas.

[0082] In this embodiment, atmospheric inductively coupled plasma 5 is ejected through torch body 8. Torch body 8 comprises an inner torch tube 81 and an outer torch tube 82. In this embodiment, both inner torch tube 81 and outer torch tube 82 are responsible for ejecting atmospheric inductively coupled plasma 5. A mixed gas is introduced into inner torch tube 81 as an excitation gas to generate active free radicals, while argon gas is introduced into outer torch tube 82 as a cooling gas to ensure that the ejected plasma 5 does not overheat.

[0083] Specifically, the inner torch 81 regulates the types of active species in the atmospheric inductively coupled plasma 5 by controlling the types of the introduced reaction gas to meet the requirements of specific applications.

[0084] At the same time, during the ejection of plasma 5, argon gas is introduced through the outer torch tube 82 as a cooling gas. Argon gas absorbs the heat released by the plasma, providing a cooling and refrigerant effect. This effectively prevents overheating of the plasma while protecting the torch body 8 from excessive temperatures. By introducing argon gas as a cooling gas through the outer torch tube 82 during the ejection of the atmospheric inductively coupled plasma 5, the stability and control of the plasma can be ensured. The flow of cooling gas removes heat from the surrounding area of ​​the torch body 8, preventing problems caused by overheating and extending the service life of the torch body 8.

[0085] In a specific embodiment, the atmospheric inductively coupled plasma 5 is obtained by a mixture of evaporation / volatile gas of the reaction liquid, oxygen and argon.

[0086] In this embodiment, the atmospheric inductively coupled plasma 5 is obtained by a mixture of the reaction liquid evaporation / volatilization gas, oxygen, and argon, wherein the reaction liquid evaporation / volatilization gas and oxygen serve as reaction gases, and argon serves as a carrier gas.

[0087] The evaporating / volatile gas from the reaction liquid is a gas capable of generating hydroxyl radicals under plasma excitation. By heating the reaction liquid and evaporating or volatilizing it into a gaseous state, the reaction liquid can be converted into a gaseous reactant. This gaseous reactant can be mixed with other gases (such as oxygen) to form a mixed gas with a specific composition. Oxygen then participates in the chemical reaction as a reactant gas. Oxygen is an essential oxidant in many chemical reactions and can promote the oxidation process of substances. It can react with the chemical substances in the evaporating / volatile gas from the reaction liquid, triggering a series of oxidation reactions, thereby promoting the formation of plasma 5.

[0088] Argon, acting as a carrier gas, dilutes the reactant gases, regulates plasma density and concentration, and provides cooling to protect the equipment. Argon is an inert gas that does not participate in chemical reactions, but it effectively dilutes other gas components and controls plasma concentration. It also cools the reaction area to prevent overheating and protect the equipment.

[0089] In a specific embodiment, the flow rate of each gas used to generate the atmospheric inductively coupled plasma 5 is controlled by a flow meter 9; different gases have corresponding flow meters 9;

[0090] The spark generator 10 and the radio frequency coil 11 are used to control the mixed gas to generate atmospheric inductively coupled plasma 5 .

[0091] In this embodiment, the flow rate of each gas used to generate the atmospheric inductively coupled plasma 5 is controlled by a flow meter 9. Different gases are provided with different flow meters 9 to ensure that the supply amount of each gas can be accurately controlled.

[0092] Flowmeter 9 is an instrument used to measure gas flow. It can monitor the flow rate and volume of the gas using various sensors or mechanisms. By configuring flowmeters 9 of different types and parameters, real-time monitoring and regulation of the flow rates of different gases can be achieved. This ensures that the proportions and concentrations of the various components in the mixed gas meet the desired requirements, thereby generating a stable atmospheric inductively coupled plasma 5.

[0093] In addition, the mixed gas is controlled by the spark generator 10 and the radio frequency coil 11 to generate atmospheric inductively coupled plasma 5. The spark generator 10 is a device for generating electric sparks, which excites the mixed gas into plasma through discharge. The radio frequency coil 11 further activates and maintains the stable state of the plasma by providing an radio frequency electric field. The use of the spark generator 10 and the radio frequency coil 11 in combination can achieve precise control of the generation of plasma from the mixed gas. By adjusting the discharge parameters of the spark generator 10 and the operating frequency of the radio frequency coil 11, the density, temperature and stability of the plasma can be adjusted to meet the needs of specific applications.

[0094] In a specific embodiment, it also includes:

[0095] The reaction rate of the atomic selective etching is controlled by controlling the flow rate of oxygen. The greater the flow rate of oxygen, the faster the reaction rate of the atomic selective etching.

[0096] In this embodiment, as shown in FIG4 , the reaction rate of the atomic selective etching is controlled by the oxygen flow rate. When the oxygen flow rate is 0, the material removal rate is 0. As the oxygen flow rate increases, the material removal rate on the diamond surface increases linearly. Within the experimental range, the material removal rate can reach a maximum of 56.53 μm / min. (It should be noted that the diamond material removal rate results are highly correlated with the sample size used, so the material removal rate of samples of different sizes will vary, but it always conforms to the rule that the material removal rate is approximately proportional to the oxygen flow rate.)

[0097] The greater the oxygen flow rate, the higher the concentration of oxygen-active free radicals in the atmospheric inductively coupled plasma 5, resulting in a higher concentration of oxygen free radicals acting on the surface of the diamond 2, thereby accelerating the reaction rate of the atomic selective etching. This method can provide more flexible and adjustable parameters to meet the requirements of different application scenarios for plasma properties. At the same time, by adjusting the oxygen flow rate, precise control of the diamond 2 polishing process can be achieved, thereby optimizing reaction efficiency and product quality.

[0098] In a specific embodiment, the atmospheric inductively coupled plasma 5 penetrates the through hole 4 and irradiates the surface of the diamond 2 sample for a time ranging from 8 minutes to 12 minutes.

[0099] In this embodiment, the atmospheric inductively coupled plasma 5 irradiates the surface of the diamond sample 2 through the through-hole 4 for a period of 8 to 12 minutes. This time range is an optimal time period determined through experiments. Within this time range, the atmospheric inductively coupled plasma 5 can fully cover the surface of the diamond sample 2 and generate sufficient chemical reactions to achieve polishing of the diamond 2.

[0100] It is important to note that the irradiation time of atmospheric inductively coupled plasma 5 is not only related to the properties of the sample and the treatment purpose, but also closely related to parameters such as plasma power and density. Therefore, during the specific implementation process, the plasma parameters need to be finely adjusted and controlled to ensure that the plasma power and density are optimal within the required treatment time range.

[0101] In a specific embodiment, the critical transition temperature is in the range of 1250°C to 1300°C.

[0102] In this embodiment, the critical transition temperature is 1270°C (it should be noted that the instantaneous temperature of the surface of the diamond 2 is measured by an infrared thermal imager, and the measurement result is related to many factors such as the measurement distance, position, imaging focal length and the calibrated sample emissivity. Therefore, the critical transition temperature will vary under different experimental conditions and needs to be calibrated according to the experimental phenomena).

[0103] The present invention selects an atmospheric inductively coupled plasma containing high-concentration and highly active oxygen free radicals and hydroxyl free radicals as the plasma source in the diamond polishing method based on plasma etching and modification. The diamond surface is flattened by combining atomic selective etching removal and hydroxyl modified polishing removal. While improving the polishing efficiency of the diamond, the polishing device is simplified, the polishing cost is reduced, and the production efficiency is improved.

[0104] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of a preferred implementation scenario, and that the modules or processes depicted in the drawings are not necessarily required to implement the present invention. Those skilled in the art will appreciate that the modules within the devices within the implementation scenarios may be distributed throughout the devices within the implementation scenarios as described in the implementation scenarios, or may be modified accordingly and located within one or more devices different from the implementation scenarios.

Claims

1. A diamond polishing method based on plasma etching and modification, characterized in that: include: The diamond to be polished is placed on a rigid polishing disc through a fixture; the rigid polishing disc is provided with a plurality of through holes extending from top to bottom; The diamond is controlled to rotate in a first direction and the rigid polishing disc is controlled to rotate in a second direction by the fixture; the first direction is opposite to the second direction; spraying atmospheric inductively coupled plasma containing oxygen free radicals and hydroxyl free radicals above the rigid polishing disk, so that the atmospheric inductively coupled plasma passes through the through hole to heat the diamond; When the instantaneous temperature is heated to a temperature exceeding the critical transition temperature corresponding to the differential etching of surface atoms, the diamond is subjected to atomic selective etching by oxygen free radicals in the atmospheric inductively coupled plasma, and at the same time, the diamond is modified by hydroxyl free radicals in the atmospheric inductively coupled plasma to complete the polishing of the diamond.

2. The method according to claim 1, wherein Also includes: The diamond is controlled by the fixture to reciprocate along the radial direction of the rigid polishing disk at a preset speed.

3. The method according to claim 2, wherein The clamp includes a rotation control part and a reciprocating control part. The rotation control part controls the diamond to rotate in the first direction. The reciprocating control part controls the diamond to perform the reciprocating motion at the preset speed along the radial direction of the rigid polishing disk.

4. The method according to claim 1, wherein A plurality of through holes are evenly arranged above the rigid polishing disk; the through holes at the same distance from the center of the rigid polishing disk are connected through flow channels; and the plurality of through holes located in the same radial direction on the rigid polishing disk are connected through radial grooves.

5. The method according to claim 1, wherein The atmospheric inductively coupled plasma is ejected through the torch body; The torch body includes an inner torch tube and an outer torch tube; The torch body ejects the atmospheric inductively coupled plasma through the outer torch tube and / or the inner torch tube; When the atmospheric inductively coupled plasma is ejected, a mixed gas is introduced into the inner torch tube as an excitation gas to generate active free radicals, and argon gas is introduced into the outer torch tube as a cooling gas.

6. The method according to claim 1 or 5, wherein: The atmospheric inductively coupled plasma is obtained by evaporating the reaction liquid / a mixed gas of volatile gas, oxygen and argon.

7. The method according to claim 6, wherein Controlling the flow rate of each of the gases used to generate the atmospheric inductively coupled plasma by a flow meter; different gases have corresponding flow meters; The mixed gas is controlled by a spark generator and a radio frequency coil to generate the atmospheric inductively coupled plasma.

8. The method according to claim 6, wherein Also includes: The reaction rate of the atomic selective etching is controlled by controlling the flow rate of the oxygen gas. The greater the flow rate of the oxygen gas, the faster the reaction rate of the atomic selective etching.

9. The method according to claim 1, characterized in that The atmospheric inductively coupled plasma penetrates the through hole and irradiates the surface of the diamond for a time range of 8 minutes to 12 minutes.

10. The method according to claim 1, characterized in that The critical transition temperature ranges from 1250°C to 1300°C.

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