Silicon Carbide Ingot Processing Method and Processing System

Abstract

The present application provides a method and a processing system for processing a silicon carbide ingot, belonging to the technical field of silicon carbide ingot processing, and solving the problem that it is difficult to process a silicon carbide ingot in the prior art. The present application includes the following steps: obtaining the roughness of the near-light surface of the ingot, where the near-light surface of the ingot is the surface facing the laser emission; screening out at least a first-level rough surface and a second-level rough surface according to the roughness of the near-light surface of the ingot, and the roughness Ra1 of the first-level rough surface is greater than the roughness Ra2 of the second-level rough surface; based on different rough surfaces, implementing a processing strategy, where the processing strategy includes: scanning the target depth area A1 of the first-level rough surface with an α1 beam to form a first modified area; scanning the target depth area A2 of the second-level rough surface with an α2 beam to form a second modified area; wherein, the pulse energy of the α1 beam is configured to be greater than the pulse energy of the α2 beam so that the slit width of the first modified area is substantially the same as the slit width of the second modified area.

Description

Technical Field

[0001] This application belongs to the technical field of silicon carbide ingot processing. Specifically, it relates to a method and a processing system for silicon carbide ingot processing. Background Art

[0002] Currently, diamond wire saws are commonly used for silicon carbide substrate cutting, but there are problems such as slow cutting speed, high material loss, and relatively large surface microcrack depth. Conventional laser cutting, such as picosecond lasers, is sensitive to surface roughness. A high-roughness surface with Ra≥1μm leads to an increase in laser scattering rate by more than 30%, uneven energy absorption, resulting in a ±15% fluctuation in the cut width and an expansion of the HAZ (heat-affected zone).

[0003] The prior art uses ultraviolet laser pre-cleaning to reduce roughness, but it will increase the process flow and cannot handle in-situ rough surfaces. High-roughness surfaces are prone to misalignment of the laser focusing position, and the thermal accumulation effect exacerbates the risk of material chipping.

[0004] Based on the above, the technical problem to be solved by this application is that it is difficult to process silicon carbide ingots with high-roughness surfaces. Summary of the Invention

[0005] The purpose of this application is to address the above problems existing in the prior art by proposing a method and a processing system for silicon carbide ingot processing, which solves the problem of difficult processing of silicon carbide ingots with high-roughness surfaces in the prior art, reduces the material chipping rate, and improves the processing quality.

[0006] The purpose of this application can be achieved by the following technical solutions: A method for processing a silicon carbide ingot, comprising the following steps: obtaining the roughness of the near-light surface of the ingot, where the near-light surface of the ingot is the surface facing the laser emission; based on the roughness of the near-light surface of the ingot, at least screening out a first-level rough surface and a second-level rough surface, and the roughness Ra1 of the first-level rough surface is greater than the roughness Ra2 of the second-level rough surface; based on different rough surfaces, implementing a processing strategy, where the processing strategy includes: scanning the target depth area A1 of the first-level rough surface with an α1 beam to form a first modified area; scanning the target depth area A2 of the second-level rough surface with an α2 beam to form a second modified area; where the pulse energy of the α1 beam is configured to be greater than the pulse energy of the α2 beam, so that the cut width of the first modified area is basically the same as the cut width of the second modified area.

[0007] In the above method for processing a silicon carbide ingot, the roughness range of the first-level rough surface is >3μm; the α1 beam is configured as: pulse energy 3J / cm 2 ~8J / cm 2 , frequency 10kHZ~50kHZ; the roughness range of the second-level rough surface is ≤3μm; the α2 beam is configured as: pulse energy 0.5J / cm2 ~1.5 J / cm 2 with a frequency of 100 kHz to 200 kHz.

[0008] In the above silicon carbide ingot processing method, the processing strategy further includes the following steps:

[0009] Superimpose radial vibration or oblique vibration on the α1 beam, and the amplitude of the superimposed radial vibration or oblique vibration is ±10 μm.

[0010] In the above silicon carbide ingot processing method, the processing strategy further includes the following steps:

[0011] The parameters of the superimposed radial vibration or oblique vibration satisfy the following relational formula: ;

[0012] where N is an integer and the range of N is [8, 100], F α1 is the frequency of the α1 beam, and F z is the frequency of superimposing radial vibration or oblique vibration on the α1 beam.

[0013] In the above silicon carbide ingot processing method, the following steps are further included: obtaining the crack width information formed by the α2 beam; based on the crack width information, determining whether the crack width > 30 μm; if the determination result is yes, starting the phase synchronization scanning of the γ beam and the α2 beam on the target depth area A2 of the ingot, the focused spot of the γ beam is configured as an annular spot, and the focused spot of the α2 beam is configured as a Gaussian spot.

[0014] In the above silicon carbide ingot processing method, the starting of the phase synchronization scanning of the γ beam and the α2 beam on the target depth area A2 of the ingot includes the following steps: controlling the time interval of the phase modulation of the γ beam and the α2 beam to be 20 ns to 50 ns, and / or controlling the spatial interval of the phase modulation of the γ beam and the α2 beam to be 50 μm to 100 μm.

[0015] In the above silicon carbide ingot processing method, the following steps are further included: obtaining the TTV value of the near-light surface of the ingot, and adjusting the focal length of the α1 beam and / or the α2 beam based on the TTV value.

[0016] In the above silicon carbide ingot processing method, the obtaining of the roughness of the near-light surface of the ingot includes the following steps: scanning the near-light surface of the ingot with the β beam; generating a virtual three-dimensional model of the ingot based on the β beam scanning data; calculating and obtaining the roughness of the near-light surface of the ingot according to the virtual three-dimensional model.

[0017] In the above silicon carbide ingot processing method, the laser wavelength of the β beam for scanning the near-light surface of the ingot is 635 nm, and the scanning resolution of the β beam is 5 μm.

[0018] In the above silicon carbide ingot processing method, the obtaining of the near-polished surface roughness of the ingot includes the following steps: photographing the near-polished surface of the ingot using a camera; generating a virtual three-dimensional model of the ingot based on the image taken by the camera; and calculating and obtaining the near-polished surface roughness of the ingot according to the virtual three-dimensional model.

[0019] Another object of the present application is also to provide a silicon carbide ingot processing system applied to the above silicon carbide ingot processing method, including: a carrier table for carrying the ingot; a detection module for detecting and obtaining the roughness of the near-polished surface of the ingot; and a cutting module for controlling the laser to cut the target depth regions corresponding to different surface roughnesses of the ingot with different parameters respectively.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] By obtaining the roughness of the near-polished surface of the ingot and then screening it into at least two groups of rough surfaces, the present application can project light beams with different pulse energies for different levels of rough surfaces, so as to ensure that the width of the modified zone cut formed after each light beam acts on the inside of the silicon carbide ingot is basically the same, reduce the chipping rate of the silicon carbide ingot processing, and improve the processing quality. Description of the Drawings

[0022] Figure 1 is a schematic flowchart of the silicon carbide ingot processing method of the present application;

[0023] Figure 2 is a schematic flowchart of roughness judgment and execution of corresponding processing strategies of the present application;

[0024] Figure 3 is a schematic flowchart of crack width judgment and execution of corresponding processing strategies of the present application;

[0025] Figure 4 is a schematic flowchart of execution of corresponding processing strategies based on the TTV value of the present application;

[0026] Figure 5 is a schematic flowchart of the first method for obtaining the ingot roughness of the present application;

[0027] Figure 6 is a schematic flowchart of the second method for obtaining the ingot roughness of the present application. Detailed Embodiments

[0028] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe in detail the specific embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0030] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0031] In the present application, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0032] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath", and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature has a lower horizontal height than the second feature.

[0033] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0034] Please refer to the Figure 1 drawings of the specification. The method for processing a silicon carbide ingot of the present application includes the following steps:

[0035] S100. Obtain the roughness of the near-light surface of the ingot, where the near-light surface of the ingot is the surface facing the laser emission;

[0036] S200. According to the roughness of the near-light surface of the ingot, at least screen out a first-level rough surface and a second-level rough surface, where the roughness Ra1 of the first-level rough surface is greater than the roughness Ra2 of the second-level rough surface;

[0037] S300. Based on different rough surfaces, execute a processing strategy. S310. The processing strategy includes: scanning the target depth region A1 of the first-level rough surface with an α1 beam to form a first modified region; scanning the target depth region A2 of the second-level rough surface with an α2 beam to form a second modified region; where the pulse energy of the α1 beam is configured to be greater than the pulse energy of the α2 beam so that the slit width of the first modified region is substantially the same as the slit width of the second modified region.

[0038] It can be understood that the near-light surface of the ingot is preferably the upper surface of the ingot, and the laser source is arranged above the upper surface of the ingot, so that the laser can be projected from top to bottom. By obtaining the roughness of the near-light surface of the ingot and screening it into at least two groups of rough surfaces, adaptive processing can be carried out for different levels of rough surfaces. For example, for the first-level rough surface with a larger roughness, the α1 beam is used for scanning, and for the second-level rough surface with a smaller roughness, the α2 beam is used for scanning. Since the roughness of the first-level rough surface is larger and it is easy to scatter, higher pulse energy is required to act on the silicon carbide ingot. While the roughness of the second-level rough surface is smaller and specular reflection is dominant, the laser energy absorption is stable and the absorption rate fluctuation is less than 5%. Therefore, the pulse energy of the α1 beam is configured to be greater than that of the α2 beam. A scanning path and a target depth are set inside the ingot below the near-light surface. The scanning path is a line-by-line scan to form a modified area, and the target depth is preferably 80% - 90% of the required wafer thickness. By projecting beams with different pulse energies for different rough surfaces, the slit width of the modified area formed after each beam acts on the inside of the silicon carbide ingot is basically the same, reducing the chipping rate of the silicon carbide ingot and improving the processing quality. Exemplarily, the α1 beam and the α2 beam are nanosecond pulsed lasers with a pulse width range of 50 ns - 500 ns. The α1 beam is used to ablate the target depth area A1 inside the ingot, and the α2 beam is used to ablate the target depth area A2 inside the ingot.

[0039] See Figure 2 , as an implementation manner, the roughness range of the first-level rough surface is > 3 μm; the α1 beam is configured as: pulse energy 3 J / cm 2 ~8 J / cm 2 , frequency 10 kHz - 50 kHz; the roughness range of the second-level rough surface is ≤ 3 μm; the α2 beam is configured as: pulse energy 0.5 J / cm 2 ~1.5 J / cm 2 , frequency 100 kHz - 200 kHz. It can be understood that when the roughness of the surface of the silicon carbide ingot is greater than 3 μm, the laser is more likely to scatter after being projected onto this surface, and the scattering rate increases by 30% - 50%, and the energy that can be effectively absorbed by the silicon carbide ingot decreases. By increasing the pulse energy to 3 J / cm 2 ~8 J / cm 2 , the energy absorption threshold can be broken through, the rough peaks can be forced to melt, and the frequency is reduced to 10 kHz - 50 kHz, so that the pulse interval is extended to avoid micro-explosion caused by thermal accumulation; the energy utilization rate can be increased from about 40% to 65%, and the cutting speed is indirectly increased to twice the original. When the roughness of the surface of the silicon carbide ingot is less than or equal to 3 μm, due to specular reflection after the laser is projected onto this surface, energy dissipation occurs. Therefore, it is necessary to avoid excessive energy from over-damaging the material. By reducing the pulse energy to 0.5 J / cm2 ~1.5 J / cm 2 , increase the frequency to 100 kHz - 200 kHz, and utilize the multi-pulse cumulative effect to achieve precise cutting.

[0040] As an implementation manner, the processing strategy further includes the following steps: superimpose radial vibration or oblique vibration on the α1 beam, and the amplitude of superimposing radial vibration or oblique vibration on the α1 beam is ±10 μm. It can be understood that by means of radial vibration or oblique vibration, the laser action point is offset by ±10 μm per second, expanding the effective irradiation area and compensating for the laser scattering loss of the first rough surface. During processing, vibration assistance can increase the laser energy absorption rate from 65% to 68%, thereby improving the cutting efficiency. It should be noted that when the amplitude exceeds ±10 μm, it will cause the laser slit to be too wide and the loss generated by cutting the wafer to be too large. Therefore, it is preferably to control the amplitude range within ±10 μm.

[0041] As an implementation manner, the processing strategy further includes the following steps: the parameters of superimposing radial vibration or oblique vibration satisfy the following relational formula: ; where N is an integer and the range of N is [8, 100]. F α1 is the frequency of the α1 beam, F z is the frequency of superimposing radial vibration or oblique vibration on the α1 beam. By configuring the multiple value N of the radial vibration or oblique vibration frequency and the α1 beam frequency to be 8 to 100 times, that is, matching the radial vibration or oblique vibration period with the laser pulse interval, ensuring that an appropriate number of laser pulses are evenly distributed within each vibration period, avoiding that the number of radial vibrations or oblique vibrations is small and the improvement of the actual energy absorption rate is small, or excessive vibration and reducing the cutting quality. Exemplarily, the preferred frequency range of F z is 0.5 kHz - 1.25 kHz. Set the frequency F z of superimposing radial vibration or oblique vibration on the α1 beam to 1 kHz, that is, the vibration interval is 1 ms, and the pulse frequency F α1 of the α1 beam is set to 50 kHz, and the pulse interval of the α1 beam is 20 μs. The vibration interval of 1 ms and the pulse interval of 20 μs of the α1 beam form an integer multiple relationship, with a difference of 50 times between them, so that 50 laser pulses are evenly distributed within each vibration period, ensuring that the heat can be periodically diffused, forming an intermittent heating and cooling cycle, and avoiding phase change damage caused by continuous thermal loading.

[0042] See Figure 3 , as an implementation manner, the silicon carbide ingot processing method of the present application further includes the following steps:

[0043] S400. Obtain the crack width information formed by the α2 beam;

[0044] S500. Determine whether the crack width > 30 μm based on the crack width information;

[0045] S600. If the determination result is yes, start the phase-synchronized scanning of the γ beam and the α2 beam on the target depth region A2 of the ingot. The focused spot of the γ beam is configured as an annular spot, and the focused spot of the α2 beam is configured as a Gaussian spot. It can be understood that since specular reflection will cause laser energy dissipation and cracks are more likely to expand, overburning needs to be avoided. The crack width information is obtained by crack detection. When the crack width exceeds the set width value, for example, exceeds 30 μm, it can be characterized that the damage of the silicon carbide ingot is too large, and this situation needs to be suppressed. By adding a γ beam and making the γ beam follow the α2 beam for synchronous scanning in a phase modulation manner, the focused spot of the γ beam is configured as an annular spot, which is different from the Gaussian spot of the α2 beam. The energy distribution of the annular spot is more uniform, which can reduce the high temperature gradient in the central region, thereby reducing the thermal stress concentration. When the γ beam scans the silicon carbide material, local heating causes the material to expand, and the surrounding colder regions restrict its expansion, thereby generating compressive stress to offset the original tensile stress, reducing the driving force for crack propagation, that is, suppressing crack propagation, and ultimately reducing the laser cutting loss. The γ beam follows the α2 beam in a phase modulation manner, which can control the interference or focal point of the laser, so that the γ beam acts in time after the action of the α2 beam, and adjusts the distribution of residual stress.

[0046] As an implementation, starting the phase-synchronized scanning of the γ beam and the α2 beam on the target depth region A2 of the ingot includes the following steps: controlling the time interval of the phase modulation of the γ beam and the α2 beam to be 20 ns - 50 ns, and / or controlling the spatial interval of the phase modulation of the γ beam and the α2 beam to be 50 μm - 100 μm. By controlling the time interval between the γ beam and the α2 beam within 20 ns - 50 ns, and / or the spatial interval within 50 μm - 100 μm, it can ensure timely intervention before crack propagation.

[0047] See Figure 4 , as an implementation, the silicon carbide ingot processing method of the present application further includes the following steps:

[0048] S700. Obtain the TTV value of the near-light surface of the ingot, and adjust the focal lengths of the α1 beam and / or the α2 beam based on the TTV value. It can be understood that by obtaining the TTV value of the near-light surface of the ingot, the position of the focusing lens can be adjusted (accuracy ±0.1 μm) to compensate for the focal length deviation caused by the surface undulation. After compensation, the consistency of the distance between the laser focus and the ingot surface can be improved, ensuring that the laser cutting position is a plane, reducing the cutting loss, and improving the cutting yield under high roughness. Exemplarily, the way to obtain the TTV value of the near-light surface of the ingot can be laser scanning or ultrasonic detection.

[0049] See Figure 5 , as an implementation, S100, obtaining the roughness of the near-light surface of the ingot includes the following steps:

[0050] S110a. Scanning the near-light surface of the ingot with a β beam;

[0051] S120a. Generating a virtual three-dimensional model of the ingot based on the β beam scanning data;

[0052] S130a. Calculating and obtaining the roughness of the near-light surface of the ingot according to the virtual three-dimensional model. It can be understood that by adding β beam scanning, non-contact high-precision surface roughness detection can be realized, avoiding the risk of scratching the ingot surface caused by traditional contact measurement. At the same time, through three-dimensional model reconstruction technology, the roughness of the near-light surface of the ingot can be accurately extracted, significantly improving the sensitivity of defect identification and the efficiency of process parameter optimization, and then improving the consistency of ingot processing.

[0053] As an implementation, the laser wavelength of the β beam scanning the near-light surface of the ingot is 635nm, and the scanning resolution of the β beam is 5μm. It can be understood that by using a β beam with a wavelength of 635nm and a high-resolution scanning configuration of 5μm, the optical properties of silicon carbide materials can be effectively adapted, background noise interference can be reduced, the stability and high precision of surface profile data can be ensured, providing a high-confidence topography reference for subsequent targeted adjustment operations, and at the same time reducing the misjudgment rate caused by insufficient resolution.

[0054] See Figure 6 , as an implementation, S100, obtaining the roughness of the near-light surface of the ingot includes the following steps:

[0055] S110b. Taking a picture of the near-light surface of the ingot with a camera;

[0056] S120b. Generating a virtual three-dimensional model of the ingot based on the camera captured image;

[0057] S130b. Calculating and obtaining the roughness of the near-light surface of the ingot according to the virtual three-dimensional model. It can be understood that through the virtual three-dimensional model reconstruction technology based on camera images, the roughness data of the near-light surface of the ingot can be quickly obtained in a low-cost and highly compatible manner, and the environmental light interference can be eliminated and the feature contrast can be enhanced by combining image processing algorithms, which is suitable for on-line detection under complex working conditions.

[0058] The silicon carbide ingot processing system (not shown in the figure) of the present application is applied to the silicon carbide ingot processing method of the present application, and includes: a carrier table, a detection module, and a cutting module. Among them, the carrier table is used to carry the ingot, the detection module is used to detect and obtain the roughness of the near-light surface of the ingot, and the cutting module is used to control the laser to cut the target depth area corresponding to different roughnesses of the ingot surface with different parameters. It can be understood that the carrier table is a vacuum adsorption stage, which can adsorb and fix the ingot for convenient processing. The cutting module is mainly the optical path part, including structures such as a laser, a mirror, a beam expander, a piezoelectric ceramic, an acousto-optic modulator, or a spatial light modulator. The acousto-optic modulator or the spatial light modulator is used to divide the beam emitted by the laser into multiple beams of the present application. The detection module includes an acoustic emission sensor and a high-speed CCD camera. The acoustic emission sensor is used to detect the signal of crack propagation formed by the α1 beam or the α2 beam cutting inside the ingot, and the high-speed CCD camera is used for visual detection of the crack width. The information detected by the detection module can be fed back to the cutting module, so as to facilitate the cutting module to adjust the α2 beam and the γ beam, such as the time interval and spatial interval of the scanning path, or laser parameters such as scanning speed, pulse width, and energy.

[0059] Beneficial effects:

[0060] In the present application, by obtaining the roughness of the near-light surface of the ingot and then screening it into at least two groups of rough surfaces, beams with different pulse energies can be projected for different levels of rough surfaces, so as to ensure that after each beam acts on the inside of the silicon carbide ingot, the cut width of the modified area formed is basically the same, reducing the chipping rate of silicon carbide ingot processing and improving the processing quality; by using the low-frequency and high-energy α1 beam to act on the high-roughness surface, breaking through the energy absorption threshold, forcibly melting the rough peaks, and extending the pulse interval, micro-explosions caused by thermal accumulation are avoided, and the energy utilization rate is increased from 40% to 65%, and the cutting speed is increased by 2 times; by making the laser action point offset ±10μm per second in the radial vibration or oblique vibration mode, the effective irradiation area is expanded, compensating for the laser scattering loss of the first rough surface, and increasing the laser energy absorption rate from 65% to 68%, thereby improving the cutting efficiency, and the ratio of the interval of the radial vibration or oblique vibration to the laser pulse interval is an integer multiple match, which can form an intermittent heating and cooling cycle, avoiding phase change damage caused by continuous thermal loading; by using the high-frequency and low-energy α2 beam, fine cutting is achieved by using the multi-pulse cumulative effect, and with the assistance of the annular light spot of the γ beam, the energy-free area in the center of the annular light spot suppresses overheating of the processed surface, and the HAZ (heat affected zone) of the processed surface can be reduced from 50μm to 15μm; by obtaining the TTV value of the near-light surface of the ingot, the position of the focusing lens can be adjusted (accuracy ±0.1μm), compensating for the focal length deviation caused by surface undulation. After compensation, the consistency of the distance between the laser focus and the ingot surface can be improved, ensuring that the position of laser cutting is a plane, reducing cutting loss, and improving the cutting yield under high roughness.

[0061] The specific embodiments described herein are merely illustrative of the spirit of this application. Those skilled in the art to which this application pertains may make various modifications or supplements to the described specific embodiments, or use similar methods for substitution, without departing from the spirit of this application or exceeding the scope defined by the appended claims.

Claims

1. A method for processing a silicon carbide ingot, characterized in that, It includes the following steps: Obtain the roughness of the near-light surface of the ingot, where the near-light surface of the ingot is the surface facing the laser emission; According to the roughness of the near-light surface of the ingot, at least screen out a first-level rough surface and a second-level rough surface. The roughness Ra1 of the first-level rough surface is greater than the roughness Ra2 of the second-level rough surface. The roughness range of the first-level rough surface is > 3μm, and the roughness range of the second-level rough surface is ≤ 3μm; Based on different rough surfaces, execute processing strategies, and the processing strategies include: Use the α1 light beam to scan the target depth area A1 of the first rough surface to form a first modified area, and the α1 light beam is configured as follows: the pulse energy is 3 J / cm 2 ~8 J / cm 2 , and the frequency is 10 kHz~50 kHz; The α2 light beam is scanned towards the target depth region A2 of the secondary rough surface to form a second modified region, and the α2 light beam is configured to have a pulse energy of 0.5 J / cm 2 ~1.5 J / cm 2 , and a frequency of 100 kHz to 200 kHz; Among them, the pulse energy of the α1 beam is configured to be greater than the pulse energy of the α2 beam, so that the slit width of the first modified area is basically the same as the slit width of the second modified area.

2. The silicon carbide ingot processing method according to claim 1, characterized in that, The processing strategy further includes the following steps: Superimpose radial vibration or oblique vibration on the α1 beam, and the amplitude of the superimposed radial vibration or oblique vibration is ±10μm.

3. The method for processing a silicon carbide ingot according to claim 2, wherein The processing strategy further includes the following steps: The parameters of the superimposed radial vibration or oblique vibration satisfy the following relational expressions: ; where N is an integer and the range of N is [8, 100], F α1 is the frequency of the α1 beam, F z is the frequency for superimposing radial vibration or oblique vibration on the α1 beam.

4. The method for processing a silicon carbide ingot according to claim 1, wherein It further includes the following steps: Obtain the crack width information formed by the α2 beam; Based on the crack width information, determine whether the crack width is > 30μm; If the determination result is yes, start the phase-synchronous scanning of the γ beam and the α2 beam on the target depth area A2 of the ingot. The focused spot of the γ beam is configured as an annular spot, and the focused spot of the α2 beam is configured as a Gaussian spot.

5. The method for processing a silicon carbide ingot according to claim 4, wherein The step of starting the phase-synchronous scanning of the γ beam and the α2 beam on the target depth area A2 of the ingot includes the following steps: Control the time interval of the phase modulation of the γ beam and the α2 beam to be 20ns - 50ns, and / or control the spatial interval of the phase modulation of the γ beam and the α2 beam to be 50μm - 100μm.

6. The silicon carbide ingot processing method according to claim 1, characterized in that, The step of obtaining the roughness of the near-light surface of the ingot includes the following steps: Scan the near-light surface of the ingot with the β beam; Generate a virtual three-dimensional model of the ingot based on the β beam scanning data; Calculate and obtain the roughness of the near-light surface of the ingot according to the virtual three-dimensional model.

7. The silicon carbide ingot processing method according to claim 6, characterized in that The laser wavelength of the β beam scanning the near-light surface of the ingot is 635nm, and the scanning resolution of the β beam is 5μm.

8. The method for processing a silicon carbide ingot according to claim 1, wherein, The step of obtaining the roughness of the near-light surface of the ingot includes the following steps: Take a picture of the near-light surface of the ingot with a camera; Generate a virtual three-dimensional model of the ingot based on the camera-captured image; Calculate and obtain the roughness of the near-light surface of the ingot according to the virtual three-dimensional model.

Images