Silicon carbide crystal ingot laser cutting method and cutting system

Abstract

The invention provides a silicon carbide crystal ingot laser cutting method and cutting system, belongs to the technical field of silicon carbide crystal ingot processing, and solves the problem of high silicon carbide crystal ingot laser cutting loss in the prior art. The cutting method comprises the following steps that the position of an operation station on a crystal ingot is obtained, and the operation station is a crystal ingot surface area facing a laser source; a scanning path and a target depth are set below the operation station, the first light beam is controlled to scan the target depth along the scanning path, and a focusing light spot of the first light beam is configured as a Gaussian light spot; crack information formed by the first light beam is obtained, the crack information comprises crack widths, and the crack widths are classified into the grade A, the grade B and the grade C in sequence from large to small; and determining a crack width level, and executing a corresponding crack control strategy. The second light beam is additionally arranged to follow the first light beam for synchronous scanning in a phase modulation mode, and the generated pressure stress can offset the original tensile stress so as to restrain crack propagation.

Description

Technical Field

[0001] The present application belongs to the technical field of silicon carbide ingot processing, and specifically, relates to a silicon carbide ingot laser cutting method and cutting system. Background Art

[0002] Currently, laser scanning and cutting is generally used inside the 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 processing silicon carbide ingots with existing lasers, due to the uneven thermal stress inside the ingots, wider cracks are easily generated on the scanning path. In addition, in order to ensure that the wafer can be effectively peeled off, the laser may need to scan repeatedly, causing the cracks to continue to expand, thereby increasing cutting losses and increasing the wafer scrap rate.

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

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

[0006] The purpose of the present application can be achieved through the following technical solutions: A method for laser cutting of silicon carbide ingots, comprising the following steps: obtaining the position of an operating station on the ingot, the operating station being the surface area of ​​the ingot facing the laser source; setting a scanning path and a target depth below the operating station, controlling a first light beam to scan the target depth along the scanning path, and configuring the focused spot of the first light beam to be a Gaussian spot; obtaining crack information formed by the first light beam, the crack information including the crack width, and grading the crack width; based on the crack width level, at least executing the following strategies: determining that the actual crack width is Class A, then executing the first crack control strategy: controlling the second light beam to scan synchronously with the first light beam, the focused spot of the second light beam being configured as an annular spot, the active area of ​​the annular spot moving with the synchronous scanning of the second light beam to phase cover the active 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.

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

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

[0009] In the above-mentioned silicon carbide ingot laser cutting method, 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.

[0010] In the above-mentioned silicon carbide ingot laser cutting method, the crack width level is based on which 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.

[0011] In the above-mentioned silicon carbide ingot laser cutting method, the crack width level is based on which at least the following strategies are implemented: When it is determined that the actual crack width is Class B, the second crack control strategy is executed: the scanning speed, pulse width and energy of the first light beam are maintained, and the crack width range of Class B is smaller than Class A and larger than Class C.

[0012] In the above-mentioned silicon carbide ingot laser cutting method, the third crack control strategy includes the following steps: The pulse width and energy of the first light beam are increased, and the scanning speed of the first light beam is reduced.

[0013] In the above-mentioned silicon carbide ingot laser cutting method, 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.

[0014] In the above-mentioned silicon carbide ingot laser cutting method, the execution of the fourth crack control strategy based on the crack extension frequency includes 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.

[0015] In the above-mentioned silicon carbide ingot laser cutting method, the wavelength of the first light beam is configured to be 1064nm, the wavelength of the second light beam is configured to be 635nm, and the energy ratio of the first light beam to the second light beam is X:Y, wherein X∈[5,8], Y∈[2,5].

[0016] In the above-mentioned silicon carbide ingot laser cutting method, the position of the operating station on the ingot is obtained, and the operating station is the surface area of ​​the ingot facing the laser source, which 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.

[0017] Another object of the present application is to provide a silicon carbide ingot cutting system, which is applied to the above-mentioned silicon carbide ingot laser cutting method, including: a supporting platform, which is used to support the ingot; a cutting module, which is used to output a first light beam and a second light beam to scan along the target depth inside the ingot; and a detection module, which is used to detect the crack extension frequency and crack width formed by the scanning of the first light beam and the second light beam, and feed back to the cutting module to control and adjust the first light beam and the second light beam.

[0018] Compared with the prior art, this application has the following beneficial effects: The present application adds a second light beam and makes the second light beam scan synchronously with the first light beam in a phase-modulated manner. The focusing spot of the second light beam is configured as an annular spot. 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 area, thereby reducing thermal stress concentration, inhibiting crack propagation, and reducing silicon carbide material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall process of the silicon carbide ingot laser cutting method of the present application; Figure 2 It is a flow chart of the first crack control strategy of the present application; Figure 3 It is a simple schematic diagram of various distribution positions of Gaussian light spots and focused light spots in this application; Figure 4 It is a flow chart of the second crack control strategy of the present application; Figure 5 is a flow chart of the third crack control strategy of the present application; Figure 6 is a flow chart of the fourth crack control strategy of the present application; In the figure, S1 is a Gaussian spot; S2 is a ring spot. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth 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 violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0021] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0023] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean 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, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0026] Please refer to the attached drawings in the instruction manual. Figure 1 and Figure 2 The silicon carbide ingot laser cutting method of the present application comprises the following steps: S100, obtaining a position of an operating station on the crystal ingot, wherein the operating station is a surface area of ​​the crystal ingot facing a laser source; S200, setting a scanning path and a target depth below the operating station, controlling the first light beam to scan the target depth along the scanning path, and configuring the focus spot of the first light beam to be a Gaussian spot; S300, obtaining crack information formed by the first light beam, S310a, the crack information includes crack width, and classifying the crack width; S400a. Based on the crack width level, at least the following strategies are executed: S410a. If the actual crack width is determined to be level A, the first crack control strategy is executed: the second light beam is controlled to scan synchronously with the first light beam in phase, and the focusing spot of the second light beam is configured as an annular spot, and the action area of ​​the annular spot moves with the synchronous scanning of the second light beam to cover the action area of ​​the Gaussian spot in phase; 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; S420a. If the actual crack width is determined to be level B, the second crack control strategy is executed: the scanning speed, pulse width and energy of the first light beam are maintained; S430a. If the actual crack width is determined to be level 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.

[0027] It is understandable that the operating station of the ingot is generally selected as the upper surface of the ingot, and when the roughness of the upper surface is less than or equal to 3μm, it is more suitable for the silicon carbide ingot laser cutting method of the present application. The upper surface of this area is dominated by mirror reflection, the laser energy absorption is stable, and the absorption rate fluctuation is less than 5%. The scanning path and target depth are set below the operating station, that is, inside the ingot. The scanning path is a line-by-line scanning to form a scanning surface, and the target depth is preferably 80% to 90% of the required wafer thickness. Exemplarily, the first light beam is a nanosecond pulse laser with a pulse width range of 50ns to 500ns and an energy density of 10J / cm 2 ~50J / cm 2 , use the first light beam to ablate the target depth area inside the ingot. Because mirror reflection will cause the laser energy to dissipate and the crack is more likely to expand, it is necessary to avoid overburning. Crack detection is used to obtain crack information. The crack information includes crack width. When the crack width exceeds the set value, such as 30μm, a second light beam can be added, and the second light beam can be scanned synchronously with the first light beam in a phase-modulated manner. The focusing spot of the second light beam is configured as an annular spot. Exemplarily, the annular spot is preferably in the shape of a circular ring, or it can be a ring of two polygons with different diameters arranged concentrically, such as a regular n-gon ring. The second light beam can be a single light beam or a combined light beam composed of multiple light beams. The combined light beam projects multiple edges or multiple points to form an annular spot. Unlike the Gaussian spot of the first light beam, the energy distribution of the annular spot is more uniform. By configuring the energy distribution of the area within the inner ring of the annular spot to 0 or extremely low, thermal stress concentration is reduced, and the range of action of the annular spot tends to cover the range of action of the Gaussian spot along the scanning path of the second light beam. The position distribution relationship between the annular spot and the Gaussian spot, such as Figure 3 The various distributions shown in (a), (b), and (c) all have a certain inhibitory effect. Figure 3 In 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, and the inner ring of S2 is controlled to move synchronously with the second light beam to cover S1 in phase. Since the area within the inner ring of the annular spot S2 has no energy to continue to project or extremely low energy to participate in the projection, the temperature is relatively low, and thermal stress can be generated from the edge of the outer ring to the inside of the inner ring, thereby limiting the expansion of the thermal stress originally generated by the Gaussian spot S1, thereby reducing the power of crack expansion, that is, inhibiting crack expansion, and ultimately reducing laser cutting losses. Figure 3 In the distribution mode of type (b), the annular area of ​​the annular spot S2 partially overlaps with the Gaussian spot S1, which can also limit the thermal stress formed by the Gaussian spot S1, but the effect is poorer than that of the distribution mode of type (a). Figure 3In the distribution mode of type (c), the Gaussian spot S1 completely falls into the annular area of ​​the annular spot S2, which has less restriction on thermal stress and is less effective than the distribution mode of type (b). Regarding the second light beam following the first light beam in a phase modulation manner, the interference or focusing point of the laser can be controlled so that the second light beam acts in time after the first light beam acts, thereby adjusting the distribution of residual stress. The time interval between the second light beam and the first light beam is controlled within 20ns to 50ns, and / or the spatial interval is controlled within 50μm to 100μm, so as to ensure timely intervention before the crack propagates. Among them, the roughness can be obtained by introducing laser scanning of the surface profile of the ingot, and the crack width in the crack information can be obtained by shooting with a CCD camera. It can be understood that by monitoring the crack width, the scanning speed, frequency and energy of the first light beam can be adjusted in time to prevent the crack from extending too much.

[0028] In some embodiments, 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 of the focus spot of the second light beam is configured to be in the range of 40 μm to 60 μm. It is understood that by configuring the focus spot diameter of the first light beam to be in the range of 15 μm to 25 μm, a qualified cutting crack can be formed, and by configuring the outer diameter of the focus spot of the second light beam to be in the range of 40 μm to 60 μm, crack expansion can be sufficiently suppressed.

[0029] In some embodiments, 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. It is understood that by setting the ratio of the inner diameter to the outer diameter of the focused spot of the second light beam to between 0.5 and 0.7, the energy distribution can be optimized so that a specific temperature field is formed inside the silicon carbide, and the temperature in the central area of ​​the temperature field is substantially consistent with the temperature in the edge area, which can promote stress release.

[0030] In some embodiments, the crack width levels are divided into Class A, Class B, and Class C from large to small. It can also be divided into Class A and Class B only, or only into Class A and Class C, and the corresponding strategy is executed according to the determined crack width level. In some embodiments, the crack width range of Class A is >30μm, the crack width range of Class B is ≥20μm and ≤30μm, and the crack width range of Class C is <20μm. Exemplarily, the standard crack width range W0 is set to 20μm to 30μm, that is, Class B is the standard crack width. If the actual crack width W monitored is within W0, it is determined that the actual crack width is Class B, see Figure 4 , the second crack control strategy is implemented: maintain the scanning speed, pulse width and energy of the first beam. Figure 5, the third crack control strategy includes the following steps: increasing the pulse width and energy of the first light beam, and reducing the scanning speed of the first light beam. If the actual crack width W monitored is less than 20μm, the actual crack width is determined to be Class C, which indicates that the cutting effect is poor. It is necessary to reduce the scanning speed of the first light beam to extend the residence time of the first light beam at the target depth to improve the cutting quality, that is, to execute the third crack control strategy. The cutting parameters can be controlled by PID closed loop.

[0031] In some embodiments, the following steps are also included: S300, obtaining crack information formed by the first light beam, S310b, the crack information including crack extension frequency; S400b, based on the crack propagation frequency, executing the fourth crack control strategy, the fourth crack control strategy includes: adjusting the time interval and / or spatial interval between the second light beam and the first light beam. It can be understood that the crack is monitored by the crack propagation frequency, so as to timely adjust the scanning phase of the second light beam and the first light beam to ensure that the crack propagation is suppressed. Among them, if it is monitored that the crack propagation frequency is too fast, it is necessary to reduce the phase of the second light beam and the first light beam, and reduce the energy of the first light beam, so as to suppress the crack propagation. If the crack propagation frequency is too slow or the crack propagation frequency is intermittent and not continuous, it is necessary to increase the phase 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, 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.

[0032] See also Figure 6 In some embodiments, S400b, executing the fourth crack control strategy based on the crack propagation frequency specifically includes the following steps: S410b, setting a standard crack growth frequency range F0, judging and comparing the actual crack growth frequency F with the standard crack growth frequency range F0; S420b, if F is greater than the maximum value of F0, then reduce the time interval and / or spatial interval between 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 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 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 propagation will be affected by factors such as beam energy and scanning speed, resulting in intermittent or continuous crack propagation. These conditions can be reflected by the frequency of crack propagation, and the frequency of crack propagation can be obtained by detecting the acoustic wave feedback generated by crack propagation. In this application, it is preferred to use an acoustic emission sensor to obtain the crack propagation frequency. Exemplarily, the standard crack propagation frequency range F0 is set to 400HZ~800HZ. If the actual crack propagation frequency F monitored exceeds 800HZ, it is characterized as too fast crack propagation. Therefore, by reducing the phase of the second light beam and the first light beam and reducing the energy of the first light beam, crack propagation is suppressed. If the actual crack propagation frequency F monitored 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 actual crack propagation frequency F monitored exceeds 800HZ, it indicates that the crack propagation is too slow or the crack propagation is intermittent and not continuous, so it is necessary to increase the phase of the second beam and the first beam, and reduce the scanning speed of the first beam and the second beam to ensure the cutting effect and prevent incomplete cutting. The cutting parameters can be controlled by PID closed loop.

[0033] In some embodiments, the wavelength of the first light beam is configured to be 1064nm, the wavelength of the second light beam is configured to be 635nm, and the energy ratio of the first light beam to the second light beam is X:Y, wherein X∈[5,8], Y∈[2,5]. It is understood that the first light beam uses a 1064nm nanosecond pulse laser with a pulse width of 50ns to 500ns and an energy density of 10J / cm 2 ~50J / cm 2 The second beam uses 635nm laser, and the ratio of the two is determined to facilitate processing.

[0034] In some embodiments, the acquisition of the position of the operating station on the ingot, where the operating station is defined as the ingot surface area with a roughness of ≤3μm and facing the laser source, includes the following steps: adding a third light beam, controlling the third light beam to scan the ingot surface to obtain the ingot surface roughness, and adjusting the pulse width and energy of the first light beam based on the ingot surface roughness. It is understandable that the third light beam is configured as a 635nm continuous laser with a power of <5W and a scanning resolution of 5μm, which can scan the surface morphology TTV and roughness value in real time and generate three-dimensional coordinates, so as to quickly find the operating station.

[0035] The silicon carbide ingot cutting system (not shown) of the present application is applied to the silicon carbide ingot laser cutting method of the present application, including: a carrier, a cutting module and a detection module, the carrier is used to carry the ingot, the cutting module is used to output the first light beam and the second light beam to scan along the target depth inside the ingot, and the detection module is used to detect the expansion frequency and crack width of the crack formed by the scanning of the first light beam and the second light beam, so as to feed back to the cutting module to control and adjust the first light beam and the second light beam. Exemplarily, the carrier is a vacuum adsorption carrier, which can adsorb and fix the ingot to facilitate processing, and the cutting module is mainly an optical path part, including lasers, reflectors, beam expanders, piezoelectric ceramics, acousto-optic modulators or spatial light modulators and other structures, and the acousto-optic modulator or spatial light modulator is used to divide the light beam emitted by the laser into the first light beam and the second light beam. The detection module includes an acoustic emission sensor and a high-speed CCD camera. The acoustic emission sensor is used to detect the frequency of crack propagation formed by the first light beam cutting the inside of the ingot. The high-speed CCD camera is used to visually detect the width of the crack. The information detected by the detection module can be fed back to the cutting module, so that the cutting module can adjust the first light beam and the second light beam, such as the time interval and spatial interval of the scanning path, or laser parameters such as scanning speed, pulse width and energy.

[0036] Beneficial effects: The present application adds a second light beam and uses phase modulation to make the second light beam scan synchronously with the first light beam. The focusing spot of the second light beam is configured as an annular spot. 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 area, thereby reducing thermal stress concentration, inhibiting crack propagation, and reducing silicon carbide material loss; by controlling the time interval between the second light beam and the first light beam within 20ns~50ns, and / or the spatial interval within 50μm~100μm, timely intervention can be ensured before the crack propagates; the crack is monitored by acquiring the crack propagation frequency, so as to timely adjust the scanning phase of the second light beam and the first light beam to ensure that the crack propagation is suppressed; by monitoring the crack width, the scanning speed, frequency and energy of the first light beam can be adjusted in time to prevent the crack from propagating too much.

[0037] The specific embodiments described herein are merely examples of the spirit of the present application. A person skilled in the art of the present application may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present application or exceed the scope defined by the attached 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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