Diamond polishing method and diamond polishing system

Abstract

The invention relates to a diamond polishing method and a diamond polishing system.The diamond polishing method comprises the steps that when a current area of a target diamond is in the laser machining process, the graphitization degree of a current machining point in the current area is detected in real time; under the condition that it is determined that the graphitization degree reaches the preset degree condition, laser machining of the current machining point is controlled to be finished, laser machining of the next machining point of the current area is controlled to be started till laser machining of the current area is completed, and mechanical polishing of the current area is controlled to be started; and after mechanical polishing of the current area is completed, the polishing quality of the current area is detected, polishing parameters are adjusted according to quantitative information of the polishing quality and preset polishing quality conditions, and laser machining and / or mechanical polishing are / is conducted on the current area based on the adjusted polishing parameters. And the polishing quality of the current area reaches the polishing quality condition. And the consistency of the polishing quality of the workpiece is improved, and the controllability of the polishing process is achieved.

Description

Technical Field

[0001] This application relates to the field of diamond processing, and in particular to diamond polishing methods and diamond polishing systems. Background Technology

[0002] Diamond, as an ultrahard material (Knoop or Vickers hardness > 40 GPa), possesses high hardness, excellent thermal conductivity, wide bandgap, and chemical stability, thus finding wide applications in high-end cutting tools, optical windows, semiconductor heat dissipation, and quantum devices. However, it is precisely these physicochemical properties of diamond, especially its hardness and chemical inertness, that make the precise and efficient polishing of diamond a manufacturing bottleneck restricting its industrial application in high-performance devices.

[0003] Currently, traditional mechanical polishing is the primary technique for processing diamond. This method relies mainly on mechanical friction and wear between the polishing disc (usually made of cast iron, tungsten carbide, or diamond) and the diamond surface to remove material. This method has low material removal efficiency, resulting in long processing cycles and high production costs. Furthermore, during polishing, the intense mechanical action can easily introduce microcracks, dislocations, and other defects into the subsurface layer of the diamond, which can degrade the mechanical, optical, and electrical properties of the final device.

[0004] To overcome the limitations of traditional mechanical polishing, laser polishing, as a non-contact processing technology, has attracted widespread attention. Among these, laser-assisted polishing (LAP) is considered an effective way to solve the processing challenges of superhard materials. The basic principle of LAP is to use a laser beam to locally irradiate the diamond surface, causing a phase transition (usually graphitization) at the irradiated area, generating a softer graphite layer. This softened layer is then easily removed mechanically, thereby improving polishing efficiency. Although this technology has made some progress, the quality and uniformity of the final graphitized layer in existing laser-assisted polishing schemes are highly dependent on the precision of the laser focus position, the stability of the beam energy distribution, and the consistency of the material itself. In actual processing, any minute fluctuations in parameters, such as fluctuations in laser pulse energy, focus drift caused by the thermal lensing effect of the focusing lens, or jitter in the scanning speed, will lead to uneven thickness or inconsistent degree of graphitization in the generated graphitized layer. This non-uniformity can cause fluctuations in material removal rate during subsequent mechanical polishing processes. It may lead to over-polishing in some areas, damaging the underlying diamond substrate, while other areas may develop "spot" defects due to graphite layer residue. Ultimately, this can severely degrade the surface flatness and surface integrity of the workpiece.

[0005] Therefore, existing laser-assisted polishing technology still suffers from poor consistency in polishing quality between different workpieces and different areas of the same workpiece, and the polishing process is uncontrollable, problems that still need to be solved. Summary of the Invention

[0006] This embodiment provides a diamond polishing method and a diamond polishing system to solve the problems in related technologies, such as poor consistency in polishing quality for different workpieces and different areas of the same workpiece, and the uncontrollable polishing process.

[0007] In a first aspect, this embodiment provides a diamond polishing method, comprising:

[0008] While the target diamond is being laser-processed in its current region, the degree of graphitization at the current processing point in the current region is detected in real time.

[0009] When the degree of graphitization reaches a preset level, control the laser processing of the current processing point to end, and control the laser processing of the next processing point in the current area to begin, until the laser processing of the current area is completed, and control the mechanical polishing of the current area to begin.

[0010] After mechanical polishing of the current area is completed, the polishing quality of the current area is detected, and the polishing parameters are adjusted according to the quantitative information of the polishing quality and the preset polishing quality conditions. Based on the adjusted polishing parameters, the current area is subjected to laser processing and / or mechanical polishing until the polishing quality of the current area reaches the polishing quality conditions.

[0011] In some embodiments, laser processing of the current region includes:

[0012] Control the picosecond laser to perform laser processing on the current area.

[0013] In some embodiments, while the current region of the target diamond is undergoing laser processing, the degree of graphitization at the current processing point in the current region is detected in real time, including:

[0014] While the target diamond is being processed by laser, real-time Raman spectral information is acquired.

[0015] The degree of graphitization at the current processing point in the current region is detected based on the Raman spectral information.

[0016] In some embodiments, detecting the degree of graphitization at the current processing point in the current region based on the Raman spectral information includes:

[0017] Extract the corresponding graphite G peak intensity and diamond D peak intensity from the Raman spectral information of the current processing point in the current region;

[0018] The degree of graphitization at the current processing point in the current region is determined based on the ratio of the graphite G peak intensity to the diamond D peak intensity.

[0019] In some embodiments, after mechanical polishing of the current area is completed, the polishing quality of the current area is detected, and polishing parameters are adjusted based on the quantitative information of the polishing quality and preset polishing quality conditions. Laser processing and / or mechanical polishing are then performed on the current area based on the adjusted polishing parameters until the polishing quality of the current area reaches the polishing quality conditions, including:

[0020] After mechanical polishing of the current area is completed, the surface roughness and removal depth of the current area are collected using a white light interferometer.

[0021] The polishing parameters are adjusted based on the surface roughness, the removal depth, and the preset polishing quality conditions.

[0022] In some embodiments, the polishing quality conditions include preset roughness target values ​​and preset depth target values; adjusting the polishing parameters according to the surface roughness, the removal depth, and the preset polishing quality conditions includes:

[0023] If the surface roughness is greater than the target roughness value, increase the mechanical polishing pressure;

[0024] If the removal depth is greater than the target depth value, the laser energy for laser processing is reduced.

[0025] Secondly, this embodiment provides a diamond polishing system, including a laser generating module, a mechanical polishing module, an online detection module, and a central control unit; wherein: the laser generating module, the mechanical polishing module, and the online detection module are all communicatively connected to the central control unit;

[0026] The laser generating module is used to perform laser processing on various areas of the target diamond;

[0027] The mechanical polishing module is used to mechanically polish various areas of the target diamond.

[0028] The online detection module is used to detect the degree of graphitization of the processing points in each region of the target diamond, as well as the polishing quality of each region;

[0029] The central control unit is used to perform the diamond polishing method described in the first aspect above.

[0030] In some embodiments, the online detection module includes a Raman spectrometer and a white light interferometer; the Raman spectrometer is coaxially integrated with the laser generation module.

[0031] The Raman spectrometer is used to detect the degree of graphitization at processing points in various regions of the target diamond in real time.

[0032] The white light interferometer is used to detect the polishing quality of each area of ​​the target diamond.

[0033] In some embodiments, the diamond polishing system further includes a motion platform;

[0034] The central control unit is used to plan the motion path of the motion platform based on the three-dimensional model of the target diamond.

[0035] The motion platform is used to carry the laser generating module, the mechanical polishing module, and the online detection module to different areas of the target diamond based on the motion path.

[0036] In some embodiments, the laser generating module includes an ultraviolet picosecond laser.

[0037] Compared with related technologies, this embodiment provides a diamond polishing method and a diamond polishing system. The diamond polishing method, while the target diamond is undergoing laser processing, continuously monitors the graphitization degree of the current processing point in the current region. If the graphitization degree reaches a preset condition, the laser processing of the current processing point is terminated, and laser processing of the next processing point in the current region is initiated, until the laser processing of the current region is completed. Then, mechanical polishing of the current region is initiated. After mechanical polishing of the current region is completed, the polishing quality of the current region is detected. Based on the quantitative information of the polishing quality and preset polishing quality conditions, the polishing parameters are adjusted, and laser processing and / or mechanical polishing are performed on the current region based on the adjusted polishing parameters until the polishing quality of the current region reaches the desired polishing quality. This improves the consistency of workpiece polishing quality and achieves controllability of the polishing process.

[0038] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0040] Figure 1 This is a hardware structure block diagram of the terminal of the diamond polishing method according to an embodiment of this application;

[0041] Figure 2 This is a flowchart of a diamond polishing method according to an embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the structure of the diamond polishing system according to an embodiment of this application;

[0043] Figure 4 This is a flowchart of a diamond polishing method according to some embodiments of this application. Detailed Implementation

[0044] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0045] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this application do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. Words such as “connected,” “linked,” and “coupled” used in this application are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific order of objects.

[0046] The method embodiments provided in this example can be executed on a terminal, computer, or similar computing device. For example, it can run on a terminal. Figure 1 This is a hardware structure block diagram of the terminal of the diamond polishing method in this embodiment. For example... Figure 1 As shown, a terminal may include one or more ( Figure 1Only one is shown in the diagram. A processor 102 and a memory 104 for storing data are also included. The processor 102 may be, but is not limited to, a microprocessor (MCU) or a programmable logic device (FPGA). The terminal may also include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that… Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the terminal described above. For example, the terminal may also include components that are larger than... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown are illustrated.

[0047] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the diamond polishing method in this embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0048] The transmission device 106 is used to receive or send data via a network. This network includes a wireless network provided by the terminal's communication provider. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 can be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0049] This embodiment provides a diamond polishing method. Figure 2 This is a flowchart of the diamond polishing method in this embodiment, as follows: Figure 2 As shown, the process includes the following steps:

[0050] Step S210: While the current area of ​​the target diamond is undergoing laser processing, the degree of graphitization at the current processing point in the current area is detected in real time.

[0051] The surface of the target diamond to be polished can be pre-divided into several regions. For example, it can be divided into multiple adjacent regions of a preset square millimeter (mm) (e.g., dividing the surface of a diamond disc into multiple adjacent 2mm × 2mm regions). Laser processing is then performed sequentially on each pre-planned processing point within each region. The polishing order of each region can be set according to a pre-planned path. When laser processing the current region, the laser can be driven to scan from the starting point of the current region, while simultaneously detecting the degree of graphitization at the processing point currently being processed by the laser in the current region in real time.

[0052] The laser used for laser processing of the target diamond can be any laser suitable for providing laser assistance in diamond polishing. Specifically, in some embodiments, it can be a picosecond laser. The current processing point can be the point of application of the laser spot. The degree of graphitization is used to characterize the extent to which a graphite layer forms at the current processing point in the current region of the target diamond under laser processing, and can be quantified as the relative content of the graphite phase and the diamond phase at the current processing point. In some embodiments, the spectral information of the current processing point can be acquired using a Raman probe, and then the graphite G peak (~1580 cm⁻¹) at the current processing point can be calculated from the spectral information. -1 Intensity (I) G ) and the diamond D peak (~1332 cm) -1 Intensity (I) D The ratio of (I) G / I D The graphitization degree can be used as a quantitative indicator. In other embodiments, X-ray photoelectron spectroscopy can be used to collect high-resolution spectra of electrons in the 1s orbitals of carbon atoms, and the graphitization progress can be judged by the area ratio of sp³ carbon bonds to sp² carbon bonds; alternatively, Raman spectroscopy can be used to calculate the full width at half maximum (FWHM) broadening or peak position shift of the diamond D peak to determine the graphitization degree; or, the absolute intensity (Ig) of the Raman diamond D peak can be calculated. D The degree of graphitization is determined by factors such as (e.g., ) and (followed by ).

[0053] Step S220: When it is determined that the degree of graphitization has reached the preset degree condition, control the end of laser processing on the current processing point and control the start of laser processing on the next processing point in the current area until the laser processing of the current area is completed, and control the start of mechanical polishing on the current area.

[0054] When the real-time detected degree of graphitization continuously increases and reaches a preset quantization threshold, it is confirmed that the degree of graphitization has reached the preset level condition. For example, if the degree of graphitization is expressed as the ratio of the intensity of the graphite G peak to the diamond D peak (I... G / I DThis means that when this ratio starts from 0 and continuously rises to a preset ratio threshold, such as 0.8, it is confirmed that the degree of graphitization has reached the preset condition. At this point, an immediate command is sent to the laser to stop laser processing at the current processing point and move to the next processing point. The next processing point is taken as the new current processing point. While laser processing is performed on the new current processing point, the corresponding degree of graphitization is also monitored in real time. When the degree of graphitization reaches the preset condition, laser processing at the current processing point ends, and the process continues to move to the next new processing point, and so on, until laser processing of all processing points in the current area is completed.

[0055] For example, the target diamond is divided into several regions, including Region 1, Region 2, and so on. First, the laser is driven to scan from the starting point within Region 1, while simultaneously detecting the degree of graphitization at the laser spot's point of action in real time. During the laser scanning process, this degree of graphitization continuously changes and increases. When the degree of graphitization at the current processing point in Region 1 reaches a preset threshold, the laser is moved to the next processing point in Region 1 for laser processing, until all processing points in Region 1 are completed.

[0056] This step enables the construction of a feedback loop to control the phase transformation degree (graphitization degree) of diamond material in the laser processing process, realizing real-time perception and control of the graphitization degree of diamond. This ensures that each processing point in a region can achieve a consistent degree of graphitization, thereby forming a uniform graphite layer with a consistent thickness (e.g., 150 nanometers (nm)).

[0057] Step S230: After completing the mechanical polishing of the current area, the polishing quality of the current area is detected, and the polishing parameters are adjusted according to the quantitative information of the polishing quality and the preset polishing quality conditions. Based on the adjusted polishing parameters, the current area is subjected to laser processing and / or mechanical polishing until the polishing quality of the current area meets the polishing quality conditions.

[0058] The polishing quality conditions can be defined as whether the surface roughness of the current area meets the preset roughness target value and whether the removal depth meets the preset depth target value. The mechanical polishing process specifically involves using a CNC polishing tool, under motor control and according to a set polishing pressure, to mechanically polish the current area to remove the graphite layer. After the mechanical polishing of the current area is completed, the current area can be scanned to measure its polishing quality. This polishing quality can be quantified by surface roughness (Ra) and average removal depth (Δz). Specifically, after mechanical polishing, the white light interferometer probe can be automatically moved to the center of the current area to perform a rapid scan (e.g., a 5-second scan) to measure the surface roughness (Ra) and average removal depth (Δz) of the current area. Subsequently, if the surface roughness of the current region is still higher than the preset roughness target value (e.g., Ra = 5nm, Δz = 108nm for the current region), the polishing pressure can be increased slightly (keeping the laser parameters constant to improve removal efficiency) to continue mechanical polishing of the current region until the surface roughness (Ra) of the current region equals the preset roughness target value. This achieves adaptive parameter adjustment of the polishing process. Conversely, if the removal depth of the current region is less than the preset depth target value, the laser energy can be increased slightly to continue laser processing followed by mechanical polishing until the removal depth equals the depth target value.

[0059] In this step, the polishing parameters are adjusted according to the rules of the adaptive algorithm and the detected polishing quality, and then the current area is further polished until the polishing quality of the current area meets the polishing quality requirements. The adjusted polishing parameters can then be used for polishing the next area. For example, if the surface roughness and removal depth of the current area meet the standards, the latest laser and mechanical polishing parameters can be maintained to polish subsequent areas until the entire workpiece is polished.

[0060] For example, after laser processing in region one is completed, the mechanical polishing tool automatically moves above region one to perform mechanical polishing, removing the graphite layer. Once polishing is complete, the probe of the white light interferometer automatically moves to the center of region one to scan it, measuring the surface roughness and average removal depth to determine the polishing quality. Based on the polishing quality test results, polishing parameters such as polishing pressure and laser energy are adjusted. Then, laser processing and / or mechanical polishing are performed on region one according to the adjusted parameters until the polishing quality of region one meets the required standards. The laser is then moved to region two, and steps S210 to S230 are repeated. This process continues until all regions of the target diamond are polished.

[0061] In this step, a feedback loop is implemented to control the entire processing process by detecting the polishing quality of the target diamond and adjusting the polishing parameters based on the feedback of the polishing quality. This allows for timely feedback and control of the polishing quality of the diamond surface, thus achieving controllable polishing quality.

[0062] In related technologies, the polishing process, due to its inability to detect differences in the material itself and fluctuations in laser energy, results in uneven thickness or varying degrees of graphitization in the generated graphitized layer. This inhomogeneity causes fluctuations in material removal rate during subsequent mechanical polishing processes, potentially leading to over-polishing in some areas and damage to the underlying diamond substrate, while other areas develop "spot" defects due to graphite layer residue, ultimately severely deteriorating the surface flatness and integrity of the workpiece. Furthermore, these technologies lack real-time feedback, making dynamic adjustments to the polishing process impossible and hindering the guarantee of consistent surface quality for each workpiece and each area within a workpiece in mass production. Therefore, these technologies suffer from uncontrollable polishing processes and poor surface quality consistency.

[0063] To address this, this embodiment constructs a dual feedback loop through steps S210 to S230. This includes a feedback loop controlling the laser processing based on the phase transformation degree (graphitization degree) of the diamond material, and a feedback loop adjusting polishing parameters based on polishing quality to control the entire processing. On one hand, addressing the problem that traditional open-loop processing cannot detect differences in the material itself (such as impurities and crystal orientation) and minute fluctuations in laser energy, this embodiment transforms the time / experience-based judgment in related technologies into a judgment based on physical state. Specifically, for difficult-to-process points (such as hard grains), more laser pulses may be needed to achieve the required graphitization degree, thus allowing the laser to remain there longer; for easy-to-process points (such as defects), the threshold may be reached quickly, allowing the laser to move away faster to prevent overheating. This ensures that every processing point on the diamond surface is processed to a consistent graphitization state, providing a highly consistent pretreatment layer for subsequent mechanical polishing and ensuring laser processing consistency. On the other hand, it allows for adaptive adjustment of polishing parameters based on the polishing quality after polishing. By combining these two feedback loops, a unique, fully closed-loop intelligent processing control system based on perception-decision-execution is formed, thereby solving the problem of control deficiency in the diamond polishing process, realizing controllable polishing quality, and improving the consistency of polishing quality.

[0064] Therefore, through the aforementioned steps S210 to S230, while the target diamond is undergoing laser processing in its current region, the degree of graphitization at the current processing point in the current region is detected in real time. If the degree of graphitization reaches a preset threshold, the laser processing at the current processing point is terminated, and laser processing at the next processing point in the current region is initiated, continuing until the laser processing of the current region is complete. Then, mechanical polishing of the current region is initiated. After mechanical polishing of the current region is completed, the polishing quality of the current region is detected, and the polishing parameters are adjusted based on the quantitative information of the polishing quality and preset polishing quality conditions. Based on the adjusted polishing parameters, laser processing and / or mechanical polishing are performed on the current region until the polishing quality of the current region meets the polishing quality conditions. This improves the consistency of workpiece polishing quality and achieves controllability of the polishing process.

[0065] In one embodiment, laser processing of the current area may include controlling a picosecond laser to perform laser processing on the current area.

[0066] Specifically, in this embodiment, a picosecond laser can be used to laser process diamond. In particular, a picosecond laser with a high repetition rate, such as a repetition rate ranging from 100 kHz to 2 MHz, and a high average power (>20 watts (W)) can be selected. Furthermore, the wavelength of the picosecond laser can be selected from ultraviolet (355 nm) or green light (532 nm).

[0067] Considering the femtosecond lasers used in related technologies, although they have shorter pulse widths, the amplification systems are more complex and the average power is lower, resulting in higher polishing costs and lower efficiency. This makes it difficult to meet the needs of large-scale industrial applications, thus causing economic and efficiency issues. Specifically, the femtosecond lasers used are relatively expensive. Furthermore, due to the lower average power and material removal rate of femtosecond lasers, although the single-point processing efficiency is higher than that of traditional mechanical polishing, the overall throughput of femtosecond lasers is still insufficient for industrial scenarios requiring the polishing of large areas (such as CVD diamond self-supported sheets and large-area windows), making it difficult to meet the needs of mass production.

[0068] Therefore, from the perspective of laser processing efficiency, this embodiment uses a picosecond laser instead of a femtosecond laser. The high repetition rate of the picosecond laser (100kHz to 2MHz) allows for more pulses to act on the material per unit time, thereby increasing the laser scanning speed. The high average power of the picosecond laser (>20W) ensures sufficient energy density to induce the diamond phase transition even at higher scanning speeds. Thus, the combination of high repetition rate and high average power enables an order-of-magnitude improvement in material removal efficiency (MMR). Furthermore, the picosecond laser maintains the cold processing characteristics of a pulse width <15 picoseconds (ps), which is much shorter than the electron-phonon coupling time of ~10ps.

[0069] Furthermore, from a cost perspective, diamond's absorption rate for ultraviolet light is much higher than that for infrared light. Therefore, the 355nm wavelength photons emitted by picosecond lasers have high energy (~3.5eV), which is closer to the band gap of diamond (~5.5eV). This allows for efficient energy deposition primarily through nonlinear effects such as two-photon absorption, rather than relying on thermal accumulation. This means that the energy utilization rate of picosecond lasers in this embodiment is higher, and the same graphitization effect can be achieved with lower pulse energy. This reduces the performance limitations of the laser, making picosecond lasers more cost-effective than expensive femtosecond lasers and lowering processing costs.

[0070] In one embodiment, while the current region of the target diamond is undergoing laser processing, the degree of graphitization at the current processing point in the current region is detected in real time. Specifically, this may include:

[0071] While the target diamond is being laser-processed in its current region, real-time Raman spectral information is acquired; based on the Raman spectral information, the degree of graphitization at the current processing point in the current region is detected.

[0072] Raman spectroscopy is a type of molecular vibrational spectroscopy; different chemical bonds and crystal structures will produce unique characteristic peaks. For example, the D peak in diamond corresponds to sp... 3 The vibration of carbon bonds, the graphite G peak corresponds to sp 2 The vibration of carbon bonds. Therefore, diamond and graphite can be distinguished based on Raman spectral information. Optionally, the laser head and Raman probe of the laser can be integrated in a coaxial design, and the laser processing optical path (incident) and the Raman signal collection optical path (outcrystallization) can be combined into one by a beam splitter, so that the laser processing point and the Raman spectral detection point coincide.

[0073] While the laser head performs laser processing on the current processing point in the current area, the Raman probe acquires the Raman spectral information of the current processing point in real time, calculates the real-time graphitization degree of the current processing point based on the Raman spectrum, and terminates the laser processing on the current processing point when the graphitization degree reaches a preset condition. Therefore, this embodiment realizes real-time monitoring of the graphitization degree based on Raman spectroscopy, improves the accuracy of graphitization degree monitoring, and thus enables timely and accurate control of the laser processing progress.

[0074] Specifically, in some embodiments, detecting the degree of graphitization at the current processing point in the current region based on Raman spectral information may include:

[0075] From the Raman spectral information of the current processing point in the current region, extract the corresponding graphite G peak intensity and diamond D peak intensity; determine the degree of graphitization of the current processing point in the current region based on the ratio of the graphite G peak intensity to the diamond D peak intensity.

[0076] After acquiring the Raman spectrum, the graphite G peak (~1580 cm⁻¹) can be calculated from the Raman spectrum. -1 The intensity of (I) G ) and the diamond D peak (~1332cm) -1 The intensity of (I) D The ratio of (I) G / I D When the ratio exceeds a preset ratio threshold, such as 0.8, graphitization is confirmed to be complete.

[0077] Specifically, the diamond D peak (~1332cm) -1 ) and graphite G peak (~1580cm) -1 ) correspond to the characteristic vibrations of sp³ and sp² carbon bonds, respectively, and the intensity ratio (I G / I D This method can quantitatively characterize the relative content of graphite and diamond phases within a micro-region. The ratio (I0.05) is... G / I D An increase in the ratio indicates graphitization is underway, while reaching a stable value indicates the phase transition is complete. Optionally, for specific optical systems and laser parameters, a ratio threshold can be determined experimentally, for example, setting the optimal ratio threshold to 0.8. When (I G / I D When the intensity ratio exceeds this threshold, it is confirmed that a graphite layer of suitable thickness has been formed at the current processing point, and the laser operation needs to be terminated immediately to achieve precise laser processing control. This avoids both insufficient graphitization at the processing point and over-processing damage to the diamond substrate. Therefore, the intensity ratio (IG) of the graphite G peak to the diamond D peak is used to determine the optimal laser processing intensity. G / I DAs a core indicator, it can improve the accuracy and convenience of judging the degree of graphitization.

[0078] The above (I) can be accomplished through a pre-set software algorithm. G / I D The calculation of the ratio (I) is as follows. G / I D In the calculation of the characteristic peaks, the original Raman spectra are first preprocessed to remove fluorescence background, making the characteristic peaks stand out from the noise background. Then, a digital filter is used to smooth the Raman spectra while preserving the original peak shape, removing high-frequency noise. Next, the peak areas of the purified characteristic peaks are quantitatively analyzed. The integration ranges of the graphite G peak and the diamond D peak are determined separately; for example, the integration range D of the diamond D peak is 1310 cm⁻¹. -1 Up to 1350cm -1 The integral range G of the graphite G peak is 1560 cm⁻¹. -1 Up to 1600cm -1 Then, software integration is used to obtain the area, which represents the intensity of each of the two characteristic peaks. The ratio of the intensities (I0) is then used to calculate the area. G / I D ) is calculated, and then this ratio (I) is used to calculate G / I D The graphitization degree is determined by comparing the graphitization degree with a preset ratio threshold.

[0079] Therefore, in this embodiment, the laser processing process is controlled by using Raman spectroscopy to feedback the graphitization degree of the diamond material. Specifically, the control criterion is that if the current processing point (I... G / I D If the ratio is less than a preset threshold, laser processing is performed on the current processing point; otherwise, laser processing on the current processing point is stopped. After laser processing of all processing points in the current area is completed, mechanical polishing is performed. This embodiment enables real-time feedback and control of the laser processing process, thereby ensuring that each processing point is processed to a consistent graphitization state, achieving controllability of the laser processing process, and providing a relatively consistent pretreatment layer for subsequent mechanical polishing.

[0080] In another embodiment, after mechanical polishing of the current area is completed, the polishing quality of the current area is detected, and the polishing parameters are adjusted based on the quantitative information of the polishing quality and the preset polishing quality conditions. Laser processing and / or mechanical polishing are then performed on the current area based on the adjusted polishing parameters until the polishing quality of the current area meets the polishing quality conditions. Specifically, this may include:

[0081] After mechanical polishing of the current area is completed, the surface roughness and removal depth of the current area are collected using a white light interferometer; the polishing parameters are adjusted according to the surface roughness, removal depth and preset polishing quality conditions.

[0082] Specifically, in the mechanical polishing process, the entire processing can be controlled based on the material surface morphology. Specifically, a white light interferometer can be used to monitor the surface roughness (Ra) and removal depth (Δz) of the current area of ​​the diamond, thereby controlling the overall processing result.

[0083] Specifically, a white light interferometer can be used to scan the current area after mechanical polishing to acquire three-dimensional topographic data. Then, the roughness component is extracted from the three-dimensional topographic data through digital filtering. Finally, the arithmetic mean deviation (Sa) of the roughness component is calculated to obtain the surface roughness. The removal depth is calculated by measuring the three-dimensional topographic data of the same area before and after polishing using a white light interferometer. Then, an algorithm is used to precisely match each point in the corresponding three-dimensional images before and after polishing, and finally, a subtraction operation is performed to obtain the removal depth.

[0084] The purpose of polishing diamond is to obtain high-quality diamonds with ultra-smooth surfaces and precise thicknesses. Surface roughness (Ra), as an industry-recognized quantifiable indicator of surface smoothness, directly determines the optical properties (such as transmittance and scattering), tribological properties, and contact thermal resistance when used as a semiconductor heat dissipation substrate for diamond workpieces. Therefore, surface roughness is the gold standard for measuring whether processing quality meets standards. Surface roughness is fed back to the mechanical polishing module to control polishing pressure, and the polishing effect is improved by adjusting the pressure or polishing time. Furthermore, considering that the thickness of the diamond workpiece also has a significant impact on the application performance of diamond, the removal depth reflects processing accuracy and safety, preventing over-processing by laser-assisted polishing and damage to the diamond itself. Therefore, the removal depth can be fed back to the laser generation module to control laser energy or scanning time to improve graphitization.

[0085] In one embodiment, the polishing quality conditions include a preset roughness target value and a preset depth target value; adjusting the polishing parameters based on the surface roughness, removal depth, and preset polishing quality conditions may specifically include:

[0086] When the surface roughness exceeds the target roughness value, increase the mechanical polishing pressure; when the removal depth exceeds the target depth value, reduce the laser energy for laser processing.

[0087] In this embodiment, the entire processing is controlled based on the polishing quality detection results of surface roughness and removal depth. The control criteria are as follows: if surface roughness (Ra) > target roughness value, the mechanical polishing pressure is increased; if removal depth > target depth value, the laser energy is reduced. This allows for adaptive adjustment of polishing parameters, improving polishing effect and efficiency.

[0088] In this embodiment, a diamond polishing system is also provided. Figure 3 This is a schematic diagram of the diamond polishing system 30 in this embodiment, as shown below. Figure 3 As shown, the diamond polishing system 30 may specifically include: a laser generating module 31, a mechanical polishing module 32, an online detection module 33, and a central control unit 34; wherein: the laser generating module 31, the mechanical polishing module 32, and the online detection module 33 are all communicatively connected to the central control unit 34; the laser generating module 31 is used to perform laser processing on various areas of the target diamond; the mechanical polishing module 32 is used to perform mechanical polishing on various areas of the target diamond; the online detection module 33 is used to detect the degree of graphitization of the processing points in various areas of the target diamond, as well as the polishing quality of each area; the central control unit 34 is used to execute the diamond polishing method provided in any of the above embodiments.

[0089] Specifically, in this embodiment, the laser generation module 31, the mechanical polishing module 32, and the online detection module 33 are all integrated on the same platform and uniformly scheduled and controlled by the central control unit 34. In this way, the central control unit 34 can ensure the precise timing matching of all control commands, thereby avoiding communication delays and coordination problems caused by discrete systems. This central control unit 34 can be an electronic device with data processing, computing, and communication capabilities. Furthermore, exemplarily, the laser generation module 31 can be an ultraviolet picosecond laser of model "Edge Wave PX100-355-GF," and the laser parameters can be set to wavelength 355nm, average power 30W, repetition frequency 500kHz (adjustable), and pulse width 10ps. The mechanical polishing module 32 can use a CNC polishing unit, where the polishing tool can be a 5mm diameter polyurethane polishing pad, and the polishing fluid can be a diamond suspension (particle size ~100nm). The polishing pressure of the mechanical polishing module 32 can be controlled by a servo motor. The range of polishing pressure can be from 0 N / m² to 20 N / m², and the resolution can be 0.1 N / m².

[0090] The central control unit 34 can be equipped with a pre-written computer program. The computer program can implement signal processing algorithms and adaptive control algorithms (i.e., the adaptive logic that adjusts the polishing parameters by polishing quality in the above embodiment), thereby realizing the diamond polishing method provided in the above embodiment. By executing this diamond polishing method, the central control unit 34 sends control commands to the laser generation module 31, the mechanical polishing module 32, and the online detection module 33 and performs information communication, thereby completing the polishing process of the target diamond.

[0091] The degree of graphitization and polishing quality conditions can be set according to the volume of the target diamond, its initial surface roughness, and the polishing target. For example, for a polycrystalline CVD diamond wafer with a diameter of 4 inches (approximately 101.6 mm) and a thickness of 500 μm, the initial surface roughness Sa > 500 nm; the polishing target for this target diamond is to polish the upper surface of the target diamond to a surface roughness Ra < 1 nm, and the surface shape accuracy is required to be a total thickness variation (TTV) < 1 μm, while avoiding the introduction of subsurface damage to ensure the relatively excellent thermal conductivity of the target diamond. Based on this, the polishing quality conditions can be set as follows: the surface roughness Ra after polishing ≤ 1 nm, and the single removal depth is 100 nm; the degree condition is set as the intensity ratio of the graphite G peak to the diamond D peak (I0). G / I D ≥0.8. In addition, the initial values ​​of other process parameters can be set: the laser parameters of the laser generation module 31 are set as follows: single pulse energy of 60 microjoules (μJ), laser scanning speed of 100mm / s, and scanning line spacing of 5μm; among the polishing parameters, the polishing pressure is 4.0N / m2, the polishing disk speed is 150 revolutions per minute (rpm), and the polishing fluid flow rate is 10ml / min.

[0092] The diamond polishing system 30 provided in this embodiment has a central control unit 34 that controls the laser generating module 31 to perform laser processing on one area of ​​the target diamond. An online detection module 33 monitors the graphitization degree of the corresponding processing point in real time, thereby controlling the laser processing process. After laser processing of one area is completed, the mechanical polishing module 32 performs mechanical polishing on that area, and the online detection module 33 then detects the polishing quality of that area. This achieves a dual-feedback intelligent control polishing processing loop, which can improve the consistency of workpiece polishing quality, realize the controllability of the polishing process, and is suitable for high-efficiency, high-precision polishing of CVD diamond heat sinks.

[0093] It should be noted that the above polishing targets and the settings of various polishing parameters are only examples. Those skilled in the art can also select other parameters according to the needs of actual application scenarios. The above examples do not constitute a specific limitation on the diamond polishing method of this embodiment.

[0094] In one embodiment, the online detection module 33 includes a Raman spectrometer and a white light interferometer; the Raman spectrometer is coaxially integrated with the laser generation module; the Raman spectrometer is used to detect the degree of graphitization of the processing points in various regions of the target diamond in real time; the white light interferometer is used to detect the polishing quality of various regions of the target diamond.

[0095] The Raman spectrometer can utilize a confocal Raman probe coaxially integrated with the laser head of the laser generation module 31. For example, the Raman spectral range can be 1000 cm⁻¹. -1 Up to 2000cm -1 The spectral acquisition time can be 10ms, and the spot diameter can be approximately 1μm. The white light interferometer can use a vertically arranged commercial WLI probe, such as the "Keyence SI-F010," with a measurement range of 100μm and a longitudinal resolution of 0.1nm for point-to-point measurement. The Raman spectrometer detects the graphitization degree of the current processing point in real time during laser processing and sends the detection results to the central control unit 34 to control the laser processing process. The white light interferometer is used to detect the polishing quality of each area after mechanical polishing and sends the detection results to the central control unit 34 to adjust the polishing parameters and perform re-laser processing and / or mechanical polishing on areas that do not meet the polishing targets. Therefore, this embodiment can achieve dual controllability of the laser processing and mechanical polishing processes, improving the consistency of polishing quality for different diamond surfaces and different diamond workpieces. Furthermore, the synchronous coaxial operation of laser processing and Raman monitoring can eliminate errors caused by measurement lag, achieving real-time control.

[0096] In addition, in one embodiment, the diamond polishing system 30 also includes a motion platform 35; the central control unit 34 is used to plan the motion path of the motion platform 35 according to the three-dimensional model of the target diamond; the motion platform 35 is used to carry the laser generating module 31, the mechanical polishing module 32 and the online detection module 33 to different areas of the target diamond based on the motion path.

[0097] In this process, a three-dimensional model of the target diamond to be polished can be pre-constructed, and then the motion path can be pre-planned based on this three-dimensional model. The motion path provides a processing path for the surface processing of the diamond, which can adapt to the polishing of complex curved surfaces, thereby improving the adaptability of diamond processing. In particular, in some embodiments, the motion platform can be extended to a five-axis system to achieve normal processing. Therefore, in some embodiments, the motion platform 35 can be a five-axis air-bearing motion platform with a positioning accuracy better than ±1μm. The motion platform 35 can be equipped with a laser generation module 31 to perform laser processing on the target diamond, a mechanical polishing module 32 to perform mechanical polishing on the target diamond, and an online detection module 33 to detect the graphitization degree and polishing quality of the target diamond.

[0098] Therefore, this embodiment can improve the adaptability to polishing diamonds with different curved surfaces and reduce the difficulty of diamond polishing.

[0099] In another embodiment, the laser generating module 31 includes an ultraviolet picosecond laser. Diamond has a much higher absorption rate for ultraviolet light than for infrared light, and the 355nm wavelength photons emitted by the picosecond laser have high energy (~3.5eV), which is closer to the band gap of diamond (~5.5eV). This allows for efficient energy deposition primarily through nonlinear effects such as two-photon absorption, rather than relying on thermal accumulation. Therefore, using an ultraviolet picosecond laser for laser processing can improve energy utilization, reduce the performance limitations of the laser, lower processing costs, and simultaneously increase laser processing efficiency.

[0100] Figure 4 These are flowcharts of diamond polishing methods according to some embodiments, such as... Figure 4 As shown, the diamond polishing method includes the following steps:

[0101] Step S401: While the ultraviolet picosecond laser is performing laser processing on the current area of ​​the target diamond, the degree of graphitization at the current processing point in the current area is detected in real time using a Raman spectrometer; wherein, the degree of graphitization is the intensity ratio of the graphite G peak to the diamond D peak.

[0102] Step S402: When it is determined that the degree of graphitization has reached the preset degree condition, control the ultraviolet picosecond laser to end the laser processing of the current processing point and start the laser processing of the next processing point in the current area until the laser processing of the current area is completed.

[0103] Step S403: Control the mechanical polishing module to perform mechanical polishing on the current area.

[0104] Step S404: After completing the mechanical polishing of the current area, the surface roughness and removal depth of the current area are detected by a white light interferometer. When the surface roughness is greater than the roughness target value, the mechanical polishing pressure is increased and the current area is mechanically polished again so that the surface roughness is less than or equal to the roughness target value. When the removal depth is greater than the depth target value, the laser energy of the laser processing is reduced.

[0105] Step S405: Take the next region as the new current region and repeat steps S401 to S404.

[0106] Steps S401 to S405 above involve using a picosecond laser to scan the diamond surface and graphitize it. Simultaneously, confocal Raman spectroscopy is used to monitor the degree of graphitization in real time, ensuring the consistency of laser processing. After laser processing, mechanical polishing is performed, and the surface quality is measured online using a white light interferometer. Finally, subsequent polishing parameters are adaptively adjusted based on the measurement results. Combining the more efficient and lower-cost picosecond laser source with online Raman and white light interferometry monitoring technology forms a unique closed-loop intelligent control system. This effectively solves the problems of low efficiency, high cost, and poor quality consistency in laser-assisted polishing technology, achieving more efficient, precise, and intelligent polishing of diamond.

[0107] From a data quantification perspective, this embodiment employs an ultraviolet picosecond laser with an average power >20W and a repetition frequency in the range of 100kHz to 2MHz. Compared to femtosecond lasers, this reduces costs by 40% to 50% and increases processing efficiency by 5 times. This embodiment introduces online Raman spectroscopy for real-time detection, which improves workpiece uniformity by 10 times compared to open-loop, feedback-free processing in related technologies. By detecting polishing quality, a second feedback loop is formed, which reduces the subsurface defect density to less than 10² / cm² (traditional polishing techniques often have a density of around 10³ / cm²). By integrating multiple modules and controlling them uniformly through a central control unit, the system response time can be reduced to below 100ms. By using a five-axis air-bearing motion platform combined with an intelligent closed-loop control mechanism, the consistency of polishing quality in different areas can be guaranteed, making it suitable for polishing large diamond workpieces larger than 4 inches.

[0108] The table below shows a comparison of the diamond polishing method of this embodiment (processing workpiece size ≥ 4 inches) and related technologies' diamond polishing methods (processing workpiece size small to medium, such as 2 inches to 3 inches):

[0109] Table 1

[0110]

[0111] In terms of material removal rate after polishing, surface accuracy, surface roughness, uniformity within the workpiece, and surface defect density after etching, the diamond polishing method of this embodiment achieves better performance than related technologies.

[0112] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated in this embodiment.

[0113] It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. All other embodiments derived by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0114] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0115] Obviously, the accompanying drawings are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar situations based on these drawings without any creative effort. Furthermore, it is understood that although the work done in this development process may be complex and lengthy, for those skilled in the art, certain design, manufacturing, or production modifications made based on the technical content disclosed in this application are merely conventional technical means and should not be considered as insufficient disclosure of this application.

[0116] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or independent of other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0117] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A diamond polishing method, characterized in that, include: While the target diamond is being laser-processed in its current region, the degree of graphitization at the current processing point in the current region is detected in real time. When the degree of graphitization reaches a preset level, control the laser processing of the current processing point to end, and control the laser processing of the next processing point in the current area to begin, until the laser processing of the current area is completed, and control the mechanical polishing of the current area to begin. After mechanical polishing of the current area is completed, the polishing quality of the current area is detected, and the polishing parameters are adjusted according to the quantitative information of the polishing quality and the preset polishing quality conditions. Based on the adjusted polishing parameters, the current area is subjected to laser processing and / or mechanical polishing until the polishing quality of the current area reaches the polishing quality conditions.

2. The diamond polishing method according to claim 1, characterized in that, Laser processing of the current area includes: Control the picosecond laser to perform laser processing on the current area.

3. The diamond polishing method according to claim 1 or claim 2, characterized in that, While the target diamond is undergoing laser processing in its current region, the degree of graphitization at the current processing point in that region is detected in real time, including: While the target diamond is being processed by laser, real-time Raman spectral information is acquired. The degree of graphitization at the current processing point in the current region is detected based on the Raman spectral information.

4. The diamond polishing method according to claim 3, characterized in that, Based on the Raman spectral information, the degree of graphitization at the current processing point in the current region is detected, including: Extract the corresponding graphite G peak intensity and diamond D peak intensity from the Raman spectral information of the current processing point in the current region; The degree of graphitization at the current processing point in the current region is determined based on the ratio of the graphite G peak intensity to the diamond D peak intensity.

5. The diamond polishing method according to claim 1, characterized in that, After completing the mechanical polishing of the current area, the polishing quality of the current area is detected. Based on the quantitative information of the polishing quality and the preset polishing quality conditions, the polishing parameters are adjusted, and the current area is subjected to laser processing and / or mechanical polishing based on the adjusted polishing parameters until the polishing quality of the current area reaches the polishing quality conditions, including: After mechanical polishing of the current area is completed, the surface roughness and removal depth of the current area are collected using a white light interferometer. The polishing parameters are adjusted based on the surface roughness, the removal depth, and the preset polishing quality conditions.

6. The diamond polishing method according to claim 5, characterized in that, The polishing quality conditions include preset roughness target values ​​and preset depth target values; The polishing parameters are adjusted based on the surface roughness, the removal depth, and preset polishing quality conditions, including: If the surface roughness is greater than the target roughness value, increase the mechanical polishing pressure; If the removal depth is greater than the target depth value, the laser energy for laser processing is reduced.

7. A diamond polishing system, characterized in that, It includes a laser generating module, a mechanical polishing module, an online detection module, and a central control unit; wherein: the laser generating module, the mechanical polishing module, and the online detection module are all communicatively connected to the central control unit; The laser generating module is used to perform laser processing on various areas of the target diamond; The mechanical polishing module is used to mechanically polish various areas of the target diamond. The online detection module is used to detect the degree of graphitization of the processing points in each region of the target diamond, as well as the polishing quality of each region; The central control unit is used to perform the diamond polishing method according to any one of claims 1 to 6.

8. The diamond polishing system according to claim 7, characterized in that, The online detection module includes a Raman spectrometer and a white light interferometer; the Raman spectrometer is coaxially integrated with the laser generation module. The Raman spectrometer is used to detect the degree of graphitization at processing points in various regions of the target diamond in real time. The white light interferometer is used to detect the polishing quality of each area of ​​the target diamond.

9. The diamond polishing system according to claim 7, characterized in that, The diamond polishing system also includes a motion platform; The central control unit is used to plan the motion path of the motion platform based on the three-dimensional model of the target diamond. The motion platform is used to carry the laser generating module, the mechanical polishing module, and the online detection module to different areas of the target diamond based on the motion path.

10. The diamond polishing system according to claim 7, characterized in that, The laser generating module includes an ultraviolet picosecond laser.

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