Polishing method for reducing surface roughness of diamond

Abstract

The invention provides a polishing method for reducing the surface roughness of diamond, and the polishing method comprises the following steps: polishing a diamond material by adopting a reactive ion etching method, the radio frequency power of the reactive ion etching method is 10-1000 W, the etching time is 1-50 min, and the adopted gas comprises one or a combination of more of Ar, O2, Cl2, BCl3, SF6, CF4 and CHF3. According to the polishing method provided by the invention, the surface smoothness of the diamond can rapidly reach the sub-nanometer level, the defects such as subsurface damage and machining stress of the diamond can be eliminated, and the surface quality of the diamond is improved.

Description

Technical Field

[0001] This invention belongs to the field of diamond surface processing technology, and specifically relates to a polishing method for reducing the surface roughness of diamond. Background Technology

[0002] Diamond, due to its excellent physicochemical properties, is widely used in optics, electronics, and high-precision tools. Existing diamond polishing methods mainly fall into two categories: mechanical polishing (MP) and chemical mechanical polishing (CMP). MP easily leads to microscopic damage to the material surface, especially when processing hard materials, potentially causing scratches or microcracks that affect subsequent performance. Furthermore, the control of roughness is highly uncertain, easily resulting in uneven surfaces after processing. CMP is relatively complex, requiring strict control of parameters such as the concentration of chemical reagents, the speed of the polishing disc, and the pressure. Moreover, both MP and CMP methods cause subsurface damage to the diamond during polishing, even leading to microcracks, and generate processing stress, reducing the surface properties of the diamond and causing significant problems for subsequent applications. Therefore, rapid and non-destructive polishing technology for diamond has always been a research hotspot and challenge in the diamond industry. Summary of the Invention

[0003] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions:

[0004] The main objective of this invention is to provide a polishing method for reducing the surface roughness of diamond, comprising: polishing diamond material using reactive ion etching, wherein the radio frequency power of the reactive ion etching method is 10W~1000W, the etching time is 1min~50min, and the gas used includes one or more combinations of Ar, O2, Cl2, BCl3, SF6, CF4, and CHF3.

[0005] Compared to traditional polishing methods, the method of this invention reduces the surface roughness of diamond at a faster rate and can eliminate defects such as subsurface damage and processing stress, thereby significantly improving the surface quality of diamond. Compared to other auxiliary chemical mechanical polishing methods, the method of this invention does not require the use of chemical reagents, is simple to operate, and is highly practical.

[0006] In some embodiments, the radio frequency power is 100W~500W, and within this preferred range, the surface roughness of the diamond is further reduced.

[0007] In some embodiments, the etching time is 5 min to 30 min, within which the surface roughness of the diamond is further reduced.

[0008] In some embodiments, the gas flow rate is 1 sccm to 500 sccm.

[0009] In some embodiments, the gas is Ar and CF4.

[0010] In some embodiments, the Ar gas flow rate is 1 sccm to 200 sccm, and the CF4 gas flow rate is 1 sccm to 100 sccm. Preferably, the Ar gas flow rate is 20 sccm to 100 sccm, and the CF4 gas flow rate is 5 sccm to 50 sccm. Within this preferred range, the surface roughness of the diamond is further reduced.

[0011] In some embodiments, the polishing method for reducing the surface roughness of diamond further includes: pre-treating and cleaning the diamond before polishing.

[0012] In some embodiments, the pretreatment cleaning specifically includes: cleaning the diamond material to be thinned in a boiling piranha solution for more than 8 hours, then cleaning it with anhydrous ethanol and / or acetone solution, and then purging it clean with inert gas.

[0013] In some embodiments, the diamond material is any one of single-crystal diamond, polycrystalline diamond, or polycrystalline diamond.

[0014] In some embodiments, the diamond material is 8 inches or larger, meaning that the method of the present invention can achieve rapid polishing of large-sized diamond materials.

[0015] Compared with existing technologies, the present invention has at least the following beneficial effects: The present invention utilizes reactive ion etching to rearrange and remove atoms on the diamond surface, repairing subsurface damage (such as subsurface damage caused by mechanical grinding and polishing) while polishing. The method provided by the present invention can not only quickly achieve sub-nanometer level smoothness on the diamond surface, but also eliminate defects such as subsurface damage and processing stress, thereby improving the surface quality of the diamond. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an atomic force microscope image of the diamond surface roughness before polishing in the embodiment;

[0018] Figure 2 This is a Raman curve of the diamond surface before polishing in the embodiment;

[0019] Figure 3 This is a laser confocal microscope image of the diamond surface before polishing in the embodiment;

[0020] Figure 4 This is an atomic force microscope image of the surface roughness of the diamond after polishing in Example 4;

[0021] Figure 5 This is a Raman curve of the diamond surface after polishing in Example 4;

[0022] Figure 6 This is a laser confocal microscope image of the diamond surface after polishing as described in Example 4. Detailed Implementation

[0023] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0024] In addition, unless otherwise specified, all raw materials used in the following embodiments can be purchased from the market or other sources, and all production and testing equipment used are known in the art, as are the testing methods used.

[0025] Example 1

[0026] This embodiment provides a polishing method for reducing the surface roughness of diamond, specifically including the following steps:

[0027] Prepare a piranha solution (with a volume ratio of H2SO4 to H2O2 of 7:3), place the diamond in the boiling piranha solution to clean for 8 hours, then repeatedly clean it in anhydrous ethanol and acetone solutions, and finally purge it with nitrogen gas.

[0028] The diamond is placed in the transmission chamber of the reactive ion etching equipment. The radio frequency power is set to 300 W and the etching time is set to 20 min. Ar and CF4 gases are used, with an Ar flow rate of 100 sccm and a CF4 flow rate of 5 sccm. The diamond is then fed into the reaction chamber to begin etching and polishing. During the etching process, Ar and CF4 rearrange and remove atoms on the diamond surface, which helps to improve the smoothness of the diamond surface.

[0029] Examples 2-5

[0030] Examples 2-5 are basically the same as Example 1, except that the Ar and CF4 gas flow rates used in Examples 2-5 are varied as shown in Table 1.

[0031] Table 1

[0032] This invention, through systematic research, has discovered that during the polishing process, Ar and CF4 rearrange and remove atoms on the diamond surface, contributing to improved surface smoothness. Furthermore, the gas flow rates of Ar and CF4 affect the surface roughness of the polished diamond. When the Ar gas flow rate is 1 sccm to 200 sccm and the CF4 gas flow rate is 1 sccm to 100 sccm, the surface roughness Ra of the diamond is relatively low. However, further research revealed that when the Ar flow rate exceeds 60 sccm, the surface roughness of the diamond increases, and when the CF4 flow rate exceeds 30 sccm, the surface roughness also increases. Therefore, considering a better surface roughness, the preferred Ar gas flow rate is 20 sccm to 100 sccm, and the preferred CF4 gas flow rate is 5 sccm to 50 sccm.

[0033] Example 6

[0034] This embodiment provides a polishing method for reducing the surface roughness of diamond, specifically including the following steps:

[0035] Prepare a piranha solution (with a volume ratio of H2SO4 to H2O2 of 7:3), place the diamond in the boiling piranha solution to clean for 8 hours, then repeatedly clean it in anhydrous ethanol and acetone solutions, and finally purge it with nitrogen gas.

[0036] The diamond is placed in the transmission chamber of the reactive ion etching equipment. The etching time is set to 10 min, the Ar gas flow rate is 60 sccm, the CF4 gas flow rate is 25 sccm, and the radio frequency power is 100 W. The diamond is then sent into the reaction chamber to begin etching and polishing.

[0037] Examples 7-15

[0038] Examples 7-15 are basically the same as Example 6, except that the etching power of Examples 7-15 varies as shown in Table 2.

[0039] Table 2

[0040] Systematic research revealed that during the etching process, the surface roughness of diamond initially decreases and then increases with increasing radio frequency (RF) power. The surface roughness increases when the RF power exceeds 500 W. Therefore, considering the need for lower surface roughness, an RF power of 100W to 500W is preferred.

[0041] Example 16

[0042] This embodiment provides a polishing method for reducing the surface roughness of diamond, specifically including the following steps:

[0043] Prepare a piranha solution (with a volume ratio of H2SO4 to H2O2 of 7:3), place the diamond in the boiling piranha solution to clean for 8 hours, then repeatedly clean it in anhydrous ethanol and acetone solutions, and finally purge it with nitrogen gas.

[0044] The diamond is placed in the transmission chamber of the reactive ion etching equipment, and the radio frequency power is set to 400 W, the Ar gas flow rate is 35 sccm, the CF4 gas flow rate is 15 sccm, and the etching time is 5 min. The diamond is then sent into the reaction chamber for etching and polishing.

[0045] Examples 17-21

[0046] Examples 17-21 are basically the same as Example 16, except that the etching time of Examples 17-21 varies as shown in Table 3.

[0047] Table 3

[0048] Through systematic research, this invention has found that the surface roughness of diamond first decreases and then increases with the increase of etching time. From the perspective of obtaining lower surface roughness, the preferred etching time is 5 min to 30 min.

[0049] Figure 1 This is an atomic force microscope image of the diamond surface roughness before polishing, used in the above embodiments; Figure 2 It is a Raman curve of the diamond surface before polishing; Figure 3 This is a laser confocal microscope image of the diamond surface before polishing. Figure 4 This is an atomic force microscope image of the surface roughness of the diamond after polishing as described in Example 4. Figure 5 This is a Raman curve of the diamond surface after polishing in Example 4. Figure 6 This is a laser confocal microscope image of the diamond surface after polishing as described in Example 4.

[0050] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0051] Existing polishing technologies (such as RIE) can partially achieve etching and polishing of diamond surfaces, but they cannot achieve non-destructive polishing, nor can they repair subsurface damage caused by mechanical grinding and polishing. Furthermore, they cannot perform large-area inch-scale polishing and achieve sub-nanometer-level surface smoothness without damaging the substrate. This invention achieves inch-scale non-destructive polishing by precisely controlling the radio frequency power, etching time, and gas type of reactive ion etching, simultaneously polishing the diamond surface to below 0.5 nm and repairing the diamond surface.

[0052] All aspects, embodiments, features, and examples of this invention should be considered illustrative and used to explain and illustrate the invention, but not to limit the invention. The scope of the invention is defined only by the claims.

[0053] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A polishing method for reducing the surface roughness of diamond, characterized in that, include: Diamond materials are polished using reactive ion etching. The radio frequency power of the reactive ion etching method is 10W~1000W, the etching time is 1min~50min, and the gas used includes one or more combinations of Ar, O2, Cl2, BCl3, SF6, CF4, and CHF3.

2. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that: The radio frequency power is 100W~500W.

3. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that: The etching time is 5 min to 30 min.

4. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that: The gas flow rate is 1 sccm to 500 sccm.

5. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that: The gases are Ar and CF4.

6. The polishing method for reducing the surface roughness of diamond according to claim 5, characterized in that: The gas flow rate of Ar is 1 sccm to 200 sccm, and the gas flow rate of CF4 is 1 sccm to 100 sccm.

7. The polishing method for reducing the surface roughness of diamond according to claim 6, characterized in that: The gas flow rate of Ar is 20 sccm to 100 sccm, and the gas flow rate of CF4 is 5 sccm to 50 sccm.

8. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that, Also includes: Before polishing, the diamond is pretreated and cleaned.

9. The polishing method for reducing the surface roughness of diamond according to claim 8, characterized in that, The pretreatment cleaning specifically includes: cleaning the diamond material to be thinned in a boiling piranha solution for more than 8 hours, then cleaning it with anhydrous ethanol and / or acetone solution, and finally purging it with inert gas.

10. The polishing method for reducing the surface roughness of diamond according to claim 1, characterized in that, The diamond material is any one of single-crystal diamond, polycrystalline diamond, or polycrystalline diamond; And / or, the diamond material is 8 inches or larger in size.

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