Laser cutting method and cutting system for silicon carbide ingot

Abstract

The present application provides a method and a cutting system for laser cutting a silicon carbide ingot, belonging to the technical field of silicon carbide ingot processing, and solving the problem of high loss in laser cutting of silicon carbide ingots in the prior art. The cutting method of the present application includes the following steps: obtaining the position of an operation station on the ingot, where the operation station is the surface area of the ingot facing the laser source; setting a scanning path and a target depth below the operation station, and controlling a first light beam to scan the target depth along the scanning path, where the focused spot of the first light beam is configured as a Gaussian spot; obtaining crack information formed by the first light beam, where the crack information includes crack width, and grading the crack width from large to small into A level, B level, and C level in sequence; determining the crack width level and implementing a corresponding crack control strategy. The present application suppresses crack propagation by adding a second light beam to synchronously scan following the first light beam in a phase modulation manner, and the generated compressive stress can offset the original tensile stress.

Description

Technical Field

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

[0002] Currently, generally, a laser is used to scan and cut inside a silicon carbide ingot to form a modified layer, and then the wafer is peeled off from the silicon carbide ingot by ultrasonic vibration or mechanical means.

[0003] However, when the existing laser processes a silicon carbide ingot, due to uneven thermal stress inside the ingot, relatively wide cracks are likely to occur on the scanning path. And to ensure that the wafer can be effectively peeled off, the laser may need to scan repeatedly for many times, resulting in the continuous expansion of the cracks, further increasing the cutting loss and the scrap rate of the wafer.

[0004] Based on the above content, the technical problem to be solved by this application is: the laser cutting loss of the silicon carbide ingot is relatively high. Summary of the Invention

[0005] The purpose of this application is to address the above problems existing in the prior art, and propose a laser cutting method and cutting system for silicon carbide ingots, which solves the problem of relatively high laser cutting loss of the existing silicon carbide ingots and reduces the laser cutting loss of the silicon carbide ingots.

[0006] The purpose of this application can be achieved by the following technical solutions: A laser cutting method for silicon carbide ingots, including the following steps: obtaining the position of the operation station on the ingot, where the operation station is the surface area of the ingot facing the laser source; setting a scanning path and a target depth below the operation station, controlling the first beam to scan the target depth along the scanning path, and the focused spot of the first beam is configured as a Gaussian spot; obtaining the crack information formed by the first beam, where the crack information includes the crack width, and classifying the crack width; based on the crack width level, at least perform the following strategy: if it is determined that the actual crack width is level A, then execute the first crack control strategy: controlling the second beam to scan synchronously with the first beam in phase, the focused spot of the second beam is configured as an annular spot, and the action area of the annular spot moves synchronously with the second beam to phase-cover the action area of the Gaussian spot; where the time interval for controlling the phase modulation of the second beam and the first beam is 20 ns to 50 ns, and / or, the spatial interval for controlling the phase modulation of the second beam and the first beam is 50 μm to 100 μm.

[0007] In the above laser cutting method for silicon carbide ingots, the cross-section of the Gaussian spot at the target depth is S1, and the cross-section of the annular spot at the target depth is S2. Control the inner ring of S2 to move synchronously with the second beam to phase-cover S1.

[0008] In the above-mentioned laser cutting method for silicon carbide ingots, the diameter range of the focused spot of the first beam is configured to be 15 μm to 25 μm, and the outer diameter range of the focused spot of the second beam is configured to be 40 μm to 60 μm.

[0009] In the above-mentioned laser cutting method for silicon carbide ingots, the ratio range of the inner diameter to the outer diameter of the focused spot of the second beam is 0.5 to 0.7.

[0010] In the above-mentioned laser cutting method for silicon carbide ingots, based on the crack width level, at least the following strategies are included:

[0011] If it is determined that the actual crack width is at level C, then implement the third crack control strategy: increase the pulse width and energy of the first beam, and reduce the scanning speed of the first beam; wherein, the crack width range at level C is smaller than that at level A.

[0012] In the above-mentioned laser cutting method for silicon carbide ingots, based on the crack width level, at least the following strategies are included:

[0013] If it is determined that the actual crack width is at level B, then implement the second crack control strategy: maintain the scanning speed, pulse width, and energy of the first beam, and the crack width range at level B is smaller than that at level A and larger than that at level C.

[0014] In the above-mentioned laser cutting method for silicon carbide ingots, the third crack control strategy includes the following steps:

[0015] Increase the pulse width and energy of the first beam, and reduce the scanning speed of the first beam.

[0016] In the above-mentioned laser cutting method for silicon carbide ingots, the following steps are further included:

[0017] The crack information includes the crack propagation frequency;

[0018] Based on the crack propagation frequency, implement the fourth crack control strategy, and the fourth crack control strategy includes: adjusting the time interval and / or spatial interval between the scanning of the second beam and the first beam.

[0019] In the above-mentioned laser cutting method for silicon carbide ingots, implementing the fourth crack control strategy based on the crack propagation frequency includes the following steps:

[0020] Set a standard crack propagation frequency range F0, and judge and compare the actual crack propagation frequency F with the standard crack propagation frequency range F0:

[0021] If F is greater than the maximum value of F0, then reduce the time interval and / or spatial interval between the scanning of the second beam and the first beam, and reduce the energy of the first beam;

[0022] If F is within the range of F0, the time interval and / or spatial interval between the scanning of the second light beam and the first light beam is maintained;

[0023] If F is less than the minimum value of F0, the time interval and / or spatial interval between the scanning of the second light beam and the first light beam is increased, and the scanning speeds of the first light beam and the second light beam are decreased.

[0024] In the above-mentioned laser cutting method for silicon carbide ingots, the wavelength of the first light beam is configured to be 1064 nm, the wavelength of the second light beam is configured to be 635 nm, and the energy ratio of the first light beam to the second light beam is X:Y, where X ∈ [5, 8] and Y ∈ [2, 5].

[0025] In the above-mentioned laser cutting method for silicon carbide ingots, obtaining the position of the operating station on the ingot, where the operating station is the surface area of the ingot facing the laser source includes the following steps: adding a third light beam, controlling the third light beam to scan the surface of the ingot to obtain the surface roughness of the ingot, and adjusting the pulse width and energy of the first light beam based on the surface roughness of the ingot.

[0026] Another object of the present application is also to provide a silicon carbide ingot cutting system, which is applied to the above-mentioned laser cutting method for silicon carbide ingots, and includes: a carrying table for carrying the ingot; a cutting module for outputting a first light beam and a second light beam to scan along the target depth inside the ingot; and a detection module for detecting the crack propagation frequency and crack width formed by the scanning of the first light beam and the second light beam, so as to feedback to the cutting module to control and adjust the first light beam and the second light beam.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] In the present application, by adding a second light beam and making the second light beam follow the first light beam to synchronously scan in a phase modulation manner, the focused spot of the second light beam is configured as an annular spot, which is different from the Gaussian spot of the first light 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, inhibiting crack propagation, and reducing the loss of silicon carbide materials. Description of the Drawings

[0029] Figure 1 is the overall process schematic diagram of the laser cutting method for silicon carbide ingots of the present application;

[0030] Figure 2 is the process schematic diagram of the first crack control strategy of the present application;

[0031] Figure 3 is the simple schematic diagram of various distribution positions of the Gaussian spot and the focused spot of the present application;

[0032] Figure 4 It is a schematic flow chart of the second crack control strategy of this application;

[0033] Figure 5 It is a schematic flow chart of the third crack control strategy of this application;

[0034] Figure 6 It is a schematic flow chart of the fourth crack control strategy of this application;

[0035] In the figure, S1 is the Gaussian light spot; S2 is the annular light spot. Specific embodiments

[0036] To make the above objects, features, and advantages of this application more obvious and understandable, the following will describe the specific embodiments of this application in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand this application. However, this 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 this application. Therefore, this application is not limited by the specific embodiments disclosed below.

[0037] In the description of this 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. They are only for the convenience of describing this 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 therefore should not be construed as a limitation of this application.

[0038] 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, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0039] In this application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0041] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can 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 only for illustrative purposes and do not represent the only embodiments.

[0042] Please refer to the Figure 1 and Figure 2 , the method for laser cutting a silicon carbide ingot of the present application includes the following steps:

[0043] S100. Obtain the position of the operation station on the ingot, where the operation station is the surface area of the ingot facing the laser source;

[0044] S200. Set a scanning path and a target depth below the operation station, and control the first beam to scan the target depth along the scanning path. The focused spot of the first beam is configured as a Gaussian spot;

[0045] S300. Obtain the crack information formed by the first beam. S310a. The crack information includes the crack width, and classify the crack width;

[0046] S400a. Based on the crack width level, at least perform the following strategies: S410a. Determine that the actual crack width is at level A, then execute the first crack control strategy: Control the second beam to scan synchronously with the first beam in phase. The focused spot of the second beam is configured as an annular spot, and the action area of the annular spot moves synchronously with the second beam scanning to cover the action area of the Gaussian spot in phase; wherein, control the time interval of phase modulation between the second beam and the first beam to be 20ns to 50ns, and / or, control the spatial interval of phase modulation between the second beam and the first beam to be 50μm to 100μm; S420a. If it is determined that the actual crack width is at level B, then execute the second crack control strategy: Maintain the scanning speed, pulse width, and energy of the first beam; S430a. If it is determined that the actual crack width is at level C, then execute the third crack control strategy: Increase the pulse width and energy of the first beam, and reduce the scanning speed of the first beam.

[0047] It can be understood that the operation station of the ingot is generally selected as the upper surface of the ingot, and when the surface roughness of this upper surface is less than or equal to 3μm, it is more suitable for the laser cutting method of the silicon carbide ingot of the present application. The upper surface of this area is mainly dominated by specular reflection, the absorption of laser energy is stable, and the absorption rate fluctuation is less than 5%. Below the operation station, that is, inside the ingot, a scanning path and a target depth are set. The scanning path is a scanning surface formed by scanning row by row, and the target depth is preferably 80% to 90% of the required wafer thickness. Exemplarily, the first beam is a nanosecond pulsed laser, the pulse width range is 50ns to 500ns, and the energy density is 10J / cm 2 ~50J / cm 2 , and use the first beam to ablate the target depth area inside the ingot. Since specular reflection will cause the laser energy to dissipate and cracks are more likely to expand, it is necessary to avoid overburning. Use crack detection to obtain crack information, and the crack information includes the crack width. When the crack width exceeds the set value, such as 30μm, a second beam can be added, and the second beam is made to follow the first beam to scan synchronously in a phase modulation manner. The focused spot of the second beam is configured as an annular spot. Exemplarily, the annular spot is preferably circular, or it can also be a ring formed by concentrically setting two polygons with different diameters, such as a regular n-sided ring. The second beam can be a single beam or a combined beam composed of multiple beams. The combined beam projects multiple sides or multiple points to form an annular spot. Different from the Gaussian spot of the first beam, the energy distribution of the annular spot is more uniform. By configuring the energy distribution of the area inside the inner ring of the annular spot to be 0 or extremely low, the thermal stress concentration is reduced, and the action range of the annular spot tends to cover the action range of the Gaussian spot as the second beam scans. The positional distribution relationship between the annular spot and the Gaussian spot, such as Figure 3 shown in (a), (b), (c), etc. in various distribution situations, all have a certain inhibitory effect. Especially Figure 3In part (a), as a preferred embodiment, the cross-section of the Gaussian spot at the target depth is S1, and the cross-section of the annular spot at the target depth is S2. The inner ring of S2 is controlled to synchronously scan and move with the second beam to phase-cover S1. Since there is no energy or extremely low energy for projection in the area inside the inner ring of the annular spot S2, the temperature is relatively low, and a thermal stress that progresses from the outer ring edge to the inner ring can be generated, thereby restricting the thermal stress expansion originally generated by the action of the Gaussian spot S1, further reducing the driving force for crack propagation, that is, suppressing crack propagation, and ultimately reducing the laser cutting loss. Figure 3 In the distribution mode of class (b), the annular region of the annular spot S2 partially overlaps with the Gaussian spot S1, and it is also possible to limit the thermal stress formed by the Gaussian spot S1, but the effect is relatively poor compared with the distribution mode of class (a). Figure 3 In the distribution mode of class (c), the Gaussian spot S1 completely falls within the annular region of the annular spot S2, and the limitation of thermal stress is small, and the effect is relatively poor compared with the distribution mode of class (b). Regarding the second beam following the first beam in a phase modulation manner, the interference or focal point of the laser can be controlled so that the second beam acts in a timely manner after the action of the first beam to adjust the distribution of residual stress. Controlling the time interval between the second beam and the first beam within 20 ns to 50 ns, and / or the spatial interval within 50 μm to 100 μm can ensure timely intervention before crack propagation. Among them, the roughness can be obtained by introducing a laser to scan the surface profile of the ingot, and the crack width in the crack information can be obtained by taking pictures with a CCD camera. It can be understood that by monitoring the crack width, the scanning speed, frequency, and energy of the first beam can be adjusted in a timely manner to prevent the crack from expanding too much.

[0048] In some embodiments, the diameter range of the focused spot of the first beam is configured to be 15 μm to 25 μm, and the outer diameter range of the focused spot of the second beam is configured to be 40 μm to 60 μm. It can be understood that by configuring the diameter of the focused spot of the first beam within the range of 15 μm to 25 μm, a qualified cutting crack can be formed, and by configuring the outer diameter of the focused spot of the second beam to be 40 μm to 60 μm, the crack expansion can be sufficiently suppressed.

[0049] In some embodiments, the ratio of the inner diameter to the outer diameter of the focused spot of the second beam ranges from 0.5 to 0.7. It can be understood that by setting the ratio of the inner diameter to the outer diameter of the focused spot of the second beam between 0.5 and 0.7, the energy distribution can be optimized, so as to form a specific temperature field inside the silicon carbide, and the temperature in the central region of the temperature field is basically the same as that in the edge region, which can promote stress release.

[0050] In some embodiments, the crack width levels are successively divided into level A, level B, and level C from large to small. It can also be divided only into level A and level B, or only into level A and level C. According to the determined crack width level, corresponding strategies are executed. In some embodiments, the crack width range of level A is > 30 μm, the crack width range of level B is ≥ 20 μm and ≤ 30 μm, and the crack width range of level C is < 20 μm. Exemplarily, the standard crack width range W0 is set to 20 μm to 30 μm, that is, level B is the standard crack width. If the monitored actual crack width W is within W0, it is determined that the actual crack width is level B. Refer to Figure 4 , then execute the second crack control strategy: maintain the scanning speed, pulse width, and energy of the first beam. Refer to Figure 5 , the third crack control strategy includes the following steps: increase the pulse width and energy of the first beam, and reduce the scanning speed of the first beam. If the monitored actual crack width W is less than 20 μm, it is determined that the actual crack width is level C, which is characterized by poor cutting effect. It is necessary to reduce the scanning speed of the first beam, so as to extend the residence time of the first beam at the target depth to improve the cutting quality, that is, execute the third crack control strategy. The cutting parameters can be controlled by PID closed-loop control.

[0051] In some embodiments, the following steps are further included:

[0052] S300. Obtain the crack information formed by the first beam, S310b. The crack information includes the crack propagation frequency;

[0053] S400b. Based on the crack propagation frequency, execute the fourth crack control strategy. The fourth crack control strategy includes: adjusting the time interval and / or spatial interval between the scanning of the second beam and the first beam. It can be understood that the crack is monitored through the crack propagation frequency, so as to timely adjust the scanning phase of the second beam and the first beam to ensure that the crack propagation is suppressed. Among them, if the monitored crack propagation frequency is too fast, it is necessary to reduce the phase between the second beam and the first beam, and reduce the energy of the first beam, so as to suppress the crack propagation. If the crack propagation frequency is too slow or the crack propagation frequency is intermittent and discontinuous, it is necessary to increase the phase between the second beam and the first beam, and reduce the scanning speeds of the first beam and the second beam, so as to ensure the cutting effect and prevent incomplete cutting. The crack propagation frequency is preferably detected by an acoustic emission sensor to obtain the sound wave generated by the crack propagation. In some embodiments, it can be detected by optical detection such as machine vision or infrared thermal imaging, or by X-ray or CT scanning, etc.

[0054] Refer to Figure 6 , in some embodiments, S400b. The step of executing the fourth crack control strategy based on the crack propagation frequency specifically includes the following steps:

[0055] S410b. Set a standard crack growth frequency range F0, and determine and compare the actual crack growth frequency F with the standard crack growth frequency range F0;

[0056] S420b. If F is greater than the maximum value of F0, then reduce the time interval and / or spatial interval between the scanning of the second light beam and the first light beam, and reduce the energy of the first light beam; if F is within the range of F0, then maintain the time interval and / or spatial interval between the scanning of the second light beam and the first light beam; if F is less than the minimum value of F0, then increase the time interval and / or spatial interval between the scanning of the second light beam and the first light beam, and reduce the scanning speed of the first light beam and the second light beam. It can be understood that crack growth will be affected by factors such as beam energy and scanning speed, resulting in intermittent or continuous crack growth. These conditions can be reflected by the frequency of crack growth, and the frequency of crack growth can be obtained through the acoustic wave feedback generated by detecting crack growth. In this application, it is preferably to use an acoustic emission sensor to obtain the crack growth frequency. Exemplarily, the standard crack growth frequency range F0 is set to 400 HZ to 800 HZ. If the monitored actual crack growth frequency F exceeds 800 HZ, it indicates that the crack growth is too fast. Therefore, by reducing the phase between the second light beam and the first light beam and reducing the energy of the first light beam, the crack growth can be inhibited. If the monitored actual crack growth frequency F is within F0, it indicates that the current cutting crack is at a normal level, and the existing cutting parameters can be maintained. If the monitored actual crack growth frequency F exceeds 800 HZ, it indicates that the crack growth is too slow or the crack growth is intermittent and discontinuous. Therefore, it is necessary to increase the phase between the second light beam and the first light beam and reduce the scanning speed of the first light beam and the second light beam to ensure the cutting effect and prevent incomplete cutting. The cutting parameters can be controlled by PID closed-loop control.

[0057] In some embodiments, the wavelength of the first light beam is configured to be 1064 nm, the wavelength of the second light beam is configured to be 635 nm, and the energy ratio of the first light beam to the second light beam is X:Y, where X ∈ [5, 8] and Y ∈ [2, 5]. It can be understood that the first light beam uses a 1064 nm nanosecond pulsed laser with a pulse width of 50 ns to 500 ns and an energy density of 10 J / cm 2 ~50 J / cm 2 , and the second light beam uses a 635 nm laser. By determining the ratio between the two, it is convenient for processing.

[0058] In some embodiments, obtaining the position of the operation station on the ingot, where the operation station is defined as the ingot surface area with a roughness ≤ 3 μm and facing the laser source, includes the following steps: adding a third beam, controlling the third beam to scan the ingot surface to obtain the surface roughness of the ingot, and based on the surface roughness of the ingot, adjusting the pulse width and energy of the first beam. It can be understood that the third beam is configured as a continuous laser of 635 nm, with a power < 5 W and a scanning resolution of 5 μm, and can scan the surface topography TTV and roughness value in real time and generate three-dimensional coordinates, so as to quickly find the operation station.

[0059] The silicon carbide ingot cutting system (not shown in the figure) of the present application is applied to the silicon carbide ingot laser cutting method of the present application, and includes: a carrier table, a cutting module, and a detection module. The carrier table is used to carry the ingot, the cutting module is used to output the first beam and the second beam to scan along the target depth inside the ingot, and the detection module is used to detect the propagation frequency and crack width of the cracks formed by the scanning of the first beam and the second beam, so as to feedback to the cutting module to control and adjust the first beam and the second beam. Exemplarily, the carrier table is a vacuum adsorption stage, which can adsorb and fix the ingot to facilitate processing. The cutting module is mainly the optical path part, including structures such as a laser, a reflector, 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 the first beam and the second beam. The detection module includes an acoustic emission sensor and a high-speed CCD camera. The acoustic emission sensor is used to detect the propagation frequency of the cracks formed by the first 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 first beam and the second beam, such as the time interval and spatial interval of the scanning path, or laser parameters such as the scanning speed, pulse width, and energy.

[0060] Beneficial effects:

[0061] In the present application, by adding a second beam and making the second beam follow the first beam to scan synchronously in a phase modulation manner, the focused spot of the second beam is configured as an annular spot, which is different from the Gaussian spot of the first 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, inhibiting crack propagation, and reducing the loss of silicon carbide material; by controlling the time interval between the second beam and the first beam within 20 ns to 50 ns, and / or the spatial interval within 50 μm to 100 μm, it can ensure timely intervention before crack propagation; by obtaining the propagation frequency of the crack to monitor the crack, the scanning phase of the second beam and the first beam can be adjusted in time to ensure that crack propagation is inhibited; by monitoring the crack width, the scanning speed, frequency, and energy of the first beam can be adjusted in time to prevent the crack from expanding too large.

[0062] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art to which the present application pertains may make various modifications or supplements to the described specific embodiments or use similar means for substitution, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A method for laser cutting of silicon carbide ingots, characterized in that: The following steps are involved: Acquire the position of an operating station on the ingot, wherein the operating station is a surface area of ​​the ingot facing the laser source; A scanning path and a target depth are set below the operating station, and a first light beam is controlled to scan the target depth along the scanning path, wherein the focus spot of the first light beam is configured as a Gaussian spot; Acquire crack information formed by the first light beam, the crack information including crack width, and classify the crack width; Based on the crack width level, at least the following strategies are implemented: If the actual crack width is determined to be Class A, the first crack control strategy is executed: the second light beam is controlled to scan synchronously with the phase of the first light beam, the focusing spot of the second light beam is configured as an annular spot, and the effective area of ​​the annular spot moves with the synchronous scanning of the second light beam to phase cover the effective area of ​​the Gaussian spot; wherein, the time interval for phase modulation of the second light beam and the first light beam is controlled to be 20ns to 50ns, and / or the spatial interval for phase modulation of the second light beam and the first light beam is controlled to be 50μm to 100μm.

2. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The cross section of the Gaussian spot at the target depth is S1, and the cross section of the annular spot at the target depth is S2. The inner ring of S2 is controlled to move synchronously with the second light beam to cover S1 in phase.

3. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The focus spot diameter of the first light beam is configured to be in the range of 15 μm to 25 μm, and the outer diameter range of the focus spot of the second light beam is configured to be in the range of 40 μm to 60 μm.

4. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The ratio of the inner diameter to the outer diameter of the focused spot of the second light beam is in the range of 0.5 to 0.

7.

5. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: Based on the crack width level, at least the following strategies are implemented: If the actual crack width is determined to be Class C, the third crack control strategy is executed: the pulse width and energy of the first light beam are increased, and the scanning speed of the first light beam is reduced; wherein the crack width range of Class C is smaller than that of Class A.

6. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The following steps are also included: The crack information includes crack propagation frequency; Based on the crack propagation frequency, a fourth crack control strategy is executed, wherein the fourth crack control strategy includes: adjusting the time interval and / or spatial interval between scanning of the second light beam and the first light beam.

7. The method for laser cutting of silicon carbide ingot according to claim 6, characterized in that: The implementation of the fourth crack control strategy based on the crack extension frequency comprises the following steps: Set a standard crack growth frequency range F0, and judge and compare the actual crack growth frequency F with the standard crack growth frequency range F0: If F is greater than the maximum value of F0, the time interval and / or spatial interval between the scanning of the second light beam and the first light beam is reduced, and the energy of the first light beam is reduced; If F is within the range of F0, the time interval and / or spatial interval between the scanning of the second light beam and the scanning of the first light beam is maintained; If F is less than the minimum value of F0, the time interval and / or spatial interval between the scanning of the second light beam and the first light beam is increased, and the scanning speed of the first light beam and the second light beam is reduced.

8. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The wavelength of the first light beam is configured to be 1064 nm, the wavelength of the second light beam is configured to be 635 nm, and the energy ratio of the first light beam to the second light beam is X:Y, wherein X∈[5,8], Y∈[2,5].

9. The method for laser cutting of silicon carbide ingot according to claim 1, characterized in that: The method of obtaining the position of an operating station on the ingot, wherein the operating station is an area on the surface of the ingot facing the laser source, includes the following steps: adding a third light beam, controlling the third light beam to scan the surface of the ingot to obtain the surface roughness of the ingot, and adjusting the pulse width and energy of the first light beam based on the surface roughness of the ingot.

10. A silicon carbide ingot cutting system, applied to the silicon carbide ingot laser cutting method according to any one of claims 1 to 9, characterized in that: include: A carrying platform, the carrying platform is used to carry the crystal ingot; A cutting module, the cutting module is used to output a first light beam and a second light beam to scan along a target depth inside the ingot; as well as A detection module is used to detect the crack extension frequency and crack width formed by scanning the first light beam and the second light beam, and to feed back to the cutting module to control and adjust the first light beam and the second light beam.

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