Laser processing method and apparatus, and device, processing device and storage medium

Abstract

A laser processing method and apparatus, and a device, a processing device and a storage medium. The laser processing method comprises: focusing a first laser on the interior of a workpiece, so as to form one or more modification marks inside the workpiece; and irradiating the modification marks by means of a second laser, so as to form absorption marks, such that cracks can be generated inside the workpiece, wherein a second-laser absorption rate of the modification marks is greater than a second-laser absorption rate of regions other than the modification marks. By means of the laser processing method, the lengths of longitudinal components of cracks can be controlled.

Description

Laser processing method, device, component, processing equipment and storage medium Technical Field The present application belongs to the field of laser processing technology, and in particular, relates to a laser processing method, device, component, processing equipment and storage medium. Background Art The third-generation semiconductor silicon carbide (SiC) has excellent physical properties such as wide bandgap, high critical breakdown field strength, and high thermal conductivity, making it an ideal substrate material for the preparation of power devices and radio frequency devices. In the process of preparing silicon carbide (SiC) substrates, it is necessary to cut silicon carbide ingots into thin silicon carbide wafers. In addition, the silicon carbide substrate needs to be thinned during the preparation of silicon carbide devices. The current processing solution is to use pulsed lasers to peel silicon carbide crystals and thin wafers. The silicon carbide ingots currently used in the semiconductor manufacturing industry are eccentric silicon carbide crystals. The top surface of the eccentric silicon carbide crystal is not parallel to the C surface, and there is a small angle α between the top surface and the C surface, which is usually 4°. Among them, the C surface is the (0001) crystal plane of silicon carbide, which is the cleavage plane with the lowest fracture toughness. When silicon carbide is cracked by laser, the crack will fluctuate up and down along the C surface, and the length of the crack in the longitudinal direction (i.e., the thickness direction or height direction) of the silicon carbide ingot is difficult to control. Summary of the invention The embodiments of the present application provide a laser processing method, apparatus, device, processing equipment and storage medium, which can control the length of the longitudinal component of the crack. In a first aspect, an embodiment of the present application provides a laser processing method, comprising: The first laser is focused on the interior of the workpiece to form one or more modification marks inside the workpiece; A second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace. In a possible implementation manner of the first aspect, the workpiece has a C surface; The first laser is focused on the interior of the workpiece to form one or more modification marks inside the workpiece, including include: The first laser moves relative to the workpiece along a first path and focuses on the inside of the workpiece to form a modified mark inside the workpiece; The second laser irradiates the modified trace to form an absorption trace so as to generate cracks inside the workpiece, comprising: The second laser moves relative to the workpiece along a second path, and the second laser irradiates the modified trace to form an absorption trace and continues to irradiate different modified traces along the second path to form the absorption trace, so that cracks can be generated inside the workpiece along the C surface; The first laser and the second laser are different lasers; The first path intersects the second path. In a possible implementation manner of the first aspect, the workpiece is a crystalline material having a crystal orientation; The second laser moves relative to the workpiece along a second path, comprising: The second laser moves relative to the workpiece along a direction parallel to the crystal direction; Alternatively, the second laser moves relative to the workpiece along a direction forming a first specified angle with the crystal direction. In a possible implementation manner of the first aspect, the workpiece further has a first positioning surface, and the first positioning surface is perpendicular to the crystal direction; The first laser moves relative to the workpiece along a first path, comprising: The first laser moves relative to the workpiece along a direction forming a second specified angle with the first positioning surface. In a possible implementation manner of the first aspect, the workpiece further has a second positioning surface, and the second positioning surface is parallel to the crystal direction; The second laser moves relative to the workpiece along a direction forming a first specified angle with the crystal direction, comprising: The second laser moves relative to the workpiece along a direction forming a first specified angle with the second positioning surface. In a possible implementation manner of the first aspect, the crystal orientation is Crystal direction; the first specified angle is greater than 0° and less than or equal to 20°. In a possible implementation manner of the first aspect, the first path includes a straight path, a concentric circle path, or a spiral path; The second path includes a straight line path or a broken line path. In a possible implementation manner of the first aspect, the first path is perpendicular to the second path. In a possible implementation of the first aspect, the peak power density of the second laser is outside the peak power density range that can produce nonlinear absorption in the area outside the modification trace alone. A laser processing device is provided, comprising: A first processing module is used to focus a first laser on the inside of the workpiece to form one or more modification marks on the inside of the workpiece; The second processing module is used to: irradiate the modified trace with a second laser to form an absorption trace, so that cracks can be generated inside the workpiece; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace. In a third aspect, an embodiment of the present application provides a device manufactured by any of the laser processing methods described above. In a fourth aspect, an embodiment of the present application provides a device having modification traces, absorption traces and cracks; The modified trace is formed by focusing the first laser on the inside of the workpiece; The crack is formed inside the workpiece by irradiating the modified trace with a second laser to form the absorption trace; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace. In a fifth aspect, an embodiment of the present application provides a processing device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the laser processing method described in any one of the first aspects above when executing the computer program. In a sixth aspect, an embodiment of the present application provides a crystalline material stripping device, comprising: an irradiation unit, configured to emit a first laser to focus on the interior of a crystal material to form one or more modified traces inside the crystal material, and to emit a second laser to irradiate the modified traces to form absorption traces, so that cracks can be generated inside the crystal material; The absorption rate of the second laser by the modified trace is greater than the absorption rate of the second laser by the area outside the modified trace; The stripping unit is used to strip a wafer from the crystal material using the crack as a starting point. In a seventh aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the laser processing method described in any one of the first aspects above is implemented. In an eighth aspect, an embodiment of the present application provides a computer program product, which, when executed on a terminal device, enables the terminal device to execute the laser processing method described in any one of the above-mentioned first aspects. The beneficial effects of the embodiments of the present application are: The first laser is focused on the inside of the silicon carbide crystal (i.e., the workpiece), causing the absorption rate of the focused area to change, forming One or more modification marks; the second laser irradiates the silicon carbide crystal (i.e., the workpiece). Since the absorption rate of the modification marks to the second laser is greater than the absorption rate of the area outside the modification marks to the second laser, the second laser is absorbed by the modification marks to form absorption marks, thereby causing cracks to be generated inside the workpiece. Due to the aforementioned difference in absorption rates, the processing effect of the second laser can be guided to the position of the modification marks of the first laser, so that cracks can basically begin to be generated at the position of the corresponding modification marks, and there are microcracks near the modification marks. The aforementioned microcracks will change the stress distribution near the tip of the crack generated by the second laser irradiating the current modification marks, thereby guiding the tip of the crack to develop to the next modification mark. In this way, the fluctuation of the crack when the second laser irradiates the workpiece can also be suppressed by the modification marks in the early stage, so that it is not easy to cause the common undesirable phenomenon of crack fluctuations being amplified by subsequent processing inside the workpiece, and the length of the longitudinal component of the crack can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work. FIG1 is a schematic structural diagram of a cylindrical silicon carbide ingot provided in one embodiment of the present application; FIG2 is a schematic diagram of the structure of a silicon carbide crystal provided in one embodiment of the present application; FIG3 is a schematic diagram of a cleavage of a positive-axis silicon carbide crystal at one angle provided by an embodiment of the present application; FIG4 is a schematic diagram of the cleavage of a positive-axis silicon carbide crystal at another angle provided by an embodiment of the present application; FIG5 is a schematic diagram of the cleavage of an off-axis silicon carbide crystal at one angle provided by an embodiment of the present application; FIG6 is a schematic diagram of the cleavage of an off-axis silicon carbide crystal at another angle provided by an embodiment of the present application; FIG7 is a schematic flow chart of a laser processing method provided in an embodiment of the present application; FIG8 is a schematic diagram of the processing effect of a first laser processing silicon carbide crystal provided in an embodiment of the present application; FIG9 is a schematic diagram of modification traces of a workpiece provided in one embodiment of the present application; FIG10 is a schematic diagram of the processing effect of a silicon carbide crystal processed by a second laser according to an embodiment of the present application; FIG11 is a schematic diagram of a workpiece after first processing by a first laser and a second laser according to an embodiment of the present application; FIG12 is a schematic diagram of a workpiece after multiple processing by a first laser and a second laser according to an embodiment of the present application; FIG13 is a schematic diagram of a crack on a C surface provided in an embodiment of the present application; FIG14 is a schematic diagram of a laser scanning processing direction and a crystal cleavage characteristic provided by an embodiment of the present application; FIG. 15 is a schematic diagram of the processing effect when the laser scanning processing direction provided by an embodiment of the present application is parallel or non-parallel to the crystal direction of the silicon carbide crystal. FIG16 is a schematic diagram of four irradiation areas of a second laser on a workpiece provided in an embodiment of the present application; FIG17 is a schematic diagram of a first irradiation area and a second irradiation area provided in an embodiment of the present application; FIG18 is a schematic diagram of a first irradiation area to a third irradiation area provided in an embodiment of the present application; FIG19 is a schematic diagram of first to fourth irradiation areas provided by an embodiment of the present application; FIG20 is a schematic diagram of the distribution of modification traces provided in one embodiment of the present application; FIG21 is a schematic diagram of cracks on adjacent C surfaces of a workpiece provided by an embodiment of the present application being connected to each other; 22 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a first processing path using a first laser according to an embodiment of the present application; 23 is a schematic diagram of the processing effect of processing a silicon carbide crystal by a first laser along a first processing path provided by another embodiment of the present application; FIG24 is a schematic diagram of a processing effect of processing a silicon carbide crystal by a first laser along a first processing path provided in another embodiment of the present application; FIG25 is a schematic diagram of a processing effect of processing a silicon carbide crystal by a first laser along a first processing path provided in another embodiment of the present application; FIG26 is a schematic diagram showing the distribution of the modification traces in the Y-axis direction according to the set spacing; FIG27 shows a schematic diagram of the cross section of the modification trace in the X-axis direction; FIG28 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a second processing path using a second laser according to an embodiment of the present application; FIG29 is a schematic diagram of a modification trace provided by another embodiment of the present application; FIG30 is a schematic structural diagram of a laser processing device provided in one embodiment of the present application; FIG31 is a schematic diagram of the structure of a processing device provided in one embodiment of the present application; FIG32 is a schematic diagram of the structure of a crystal material stripping device provided in one embodiment of the present application. DETAILED DESCRIPTION In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with Figures 1 to 32 and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application. It should be understood that when used in this specification and the appended claims, the term "comprising" indicates that the described features The existence of a feature, integer, step, operation, element and / or component does not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components and / or their collections. It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations. As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context. In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance. References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. The embodiments of the present application provide a laser processing method, which can be used to peel off a workpiece (i.e., a method for peeling off a workpiece by laser) or to reduce the thickness of a workpiece (i.e., a method for reducing the thickness of a workpiece by laser). The aforementioned workpiece can be a crystalline material. The aforementioned crystalline material can be a silicon carbide material, such as a columnar silicon carbide ingot or a thin layer of silicon carbide wafer. FIG1 is a schematic diagram of the structure of a cylindrical silicon carbide ingot provided in an embodiment of the present application. Referring to FIG1 , an embodiment of the present application is described by taking a cylindrical silicon carbide ingot as an example. A cylindrical silicon carbide ingot 100 has a first surface 103 and a second surface 104 which are parallel to each other; in the height direction (i.e., the thickness direction) of the cylindrical silicon carbide ingot, the first surface 103 is an upper surface, and the second surface 104 is a lower surface. The first surface 103 can be a polished plane. The crystal material (such as a cylindrical silicon carbide ingot) is processed with a first positioning surface 101 and a second positioning surface 102. The function of the first positioning surface 101 and the second positioning surface 102 is to determine the crystal orientation of the crystal material. The length of the first positioning surface 101 is L1, and the length of the second positioning surface is L2, and L1>L2. Among them, the first positioning surface 101 of the crystal material is parallel to the X-axis direction, the second positioning surface 102 is parallel to the Y-axis direction, and the height direction of the crystal material is parallel to the Z-axis direction. FIG2 is a schematic diagram of the structure of a silicon carbide crystal provided in an embodiment of the present application. Referring to FIG2, silicon carbide crystal is a typical polymorph with hundreds of crystal structures, one of which is 4H-SiC crystal. Commercial substrate materials are mainly 4H-SiC crystals, so 4H-SiC crystals are used as an example for illustration. The laser processing method provided in an embodiment of the present application is also applicable to other silicon carbide crystals (such as 6H-SiC, etc.). 2, 4H-SiC crystal has a hexagonal structure, including three main cleavage planes: (0001) crystal plane (also called C plane), Crystal plane and Crystal planes; and the crystal directions perpendicular to the corresponding crystal planes:

[0001] Crystalline direction (also called C-axis), Crystal orientation and Crystal orientation. Among the three main cleavage planes, the fracture toughness of the C plane (0001) is the smallest. Therefore, when a crack is generated in a silicon carbide crystal under the action of external force, the crack tends to extend along the C plane (0001). According to the geometric structure of the crystal material, silicon carbide crystals are divided into on-axis silicon carbide crystals and off-axis silicon carbide crystals. FIG. 3 is a schematic diagram of a cleavage of an on-axis silicon carbide crystal at one angle provided by an embodiment of the present application. FIG. 4 is a schematic diagram of a cleavage of an on-axis silicon carbide crystal at another angle provided by an embodiment of the present application. Referring to FIG. 3 and FIG. 4, the first surface 103 of the on-axis silicon carbide crystal is parallel to the C-plane of the silicon carbide crystal. In addition, the crystal orientation Parallel to the first positioning plane 101 of the silicon carbide crystal, the crystal direction The axis 201 is parallel to the second positioning surface 102 of the silicon carbide crystal. The axis 201 represents an imaginary straight line perpendicular to the first surface 103 of the crystal. For the positive axis silicon carbide crystal, the axis 201 is parallel to the C axis 210 of the crystal. When a cleavage crack is generated inside the positive axis silicon carbide crystal, the crack propagates along the C plane (0001), and the peeling surface formed by the crack propagation is finally parallel to the first surface 103. FIG5 is a schematic diagram of the cleavage of an off-axis silicon carbide crystal at one angle provided in an embodiment of the present application. FIG6 is a schematic diagram of the cleavage of an off-axis silicon carbide crystal at another angle provided in an embodiment of the present application. Referring to FIG5 and FIG6, the first surface 103 of the off-axis silicon carbide crystal is not parallel to the C-plane (0001), and the first surface 103 and the C-plane (0001) form a small angle α, α is usually 4°, and the first surface 103 of other off-axis crystal materials (such as gallium nitride) is also not parallel to the C-plane (0001). Among them, there are many C-planes inside the silicon carbide crystal, and each C-plane is parallel to each other. Axis 201 represents an imaginary straight line perpendicular to the first surface 103 of the crystal. Referring to FIG6, for the off-axis silicon carbide crystal, the axis 201 presents a 4° inclination angle α with the C-axis. When a cleavage crack is generated inside the off-axis silicon carbide crystal, the crack propagates along the C-plane (0001), and the peeling plane formed by the crack propagation will be inclined at a 4° angle to the first surface 103. When the silicon carbide is cracked by the laser, the crack will fluctuate up and down along the C-plane, and the length of the crack in the longitudinal direction (i.e., the thickness direction or the height direction) of the silicon carbide ingot is difficult to control. Fig. 7 is a schematic flow chart of a laser processing method provided in an embodiment of the present application. Referring to Fig. 7, in order to solve the above technical problem, the laser processing method provided in an embodiment of the present application includes step A1 and step A2. Step A1: A first laser is focused on the interior of a workpiece to form one or more modification marks inside the workpiece. FIG8 is a schematic diagram of the processing effect of the first laser processing silicon carbide crystal provided by an embodiment of the present application. FIG9 is a schematic diagram of the modification traces of the workpiece provided by an embodiment of the present application. Referring to FIG8 and FIG9, the first laser has a wavelength that is relatively transparent to the silicon carbide crystal (i.e., the workpiece). The first laser is focused to the inside of the silicon carbide crystal, such as the silicon carbide crystal is moved relative to the silicon carbide crystal. The focus moves and focuses to the inside of the silicon carbide crystal, forming a modified trace 300 inside the silicon carbide crystal, and the number of the modified trace 300 can be one or more; wherein the focusing depth is equal to the thickness of the wafer that needs to be peeled off from the silicon carbide crystal. The first laser is focused on the silicon carbide crystal to achieve modification, and a modification mark 300 is formed inside the workpiece. For example, the first laser is focused on the silicon carbide crystal, so that the single-crystalline silicon carbide crystal is transformed into a polycrystalline silicon carbide crystal. Of course, when the first laser is focused on the silicon carbide crystal, gasification or sublimation may occur; therefore, the modification mark contains polycrystalline silicon carbide crystals. The modification mark 300 can be point-shaped or line-shaped, such as points spaced apart along the direction in which the first laser moves or a continuous line (such as a straight line, a circular line, or a spiral) along the direction in which the first laser moves. Along with the formation of the modification mark 300 , micro cracks exist near the modification mark 300 . The micro cracks are tiny cracks that are invisible to the naked eye. It should be understood that by setting the power, pulse width, spot size, central wavelength, repetition frequency and other parameters of the first laser, the first laser can be focused on the silicon carbide crystal to modify the silicon carbide crystal. For example, the pulsed laser of the first pulse width moves relative to the silicon carbide crystal (i.e., the workpiece) and focuses on the inside of the silicon carbide crystal (i.e., the workpiece), so that the silicon carbide crystal is modified. In practical applications, the laser processing head can emit a first laser. The laser processing head moves relative to the silicon carbide crystal (i.e., the workpiece), and the laser processing head emits the first laser; for example, the laser processing head moves relative to the silicon carbide crystal (i.e., the workpiece) while emitting the first laser to process the silicon carbide crystal (i.e., the workpiece); or, after the laser processing head moves relative to the silicon carbide crystal (i.e., the workpiece) to a processing position, it emits the first laser to process the silicon carbide crystal (i.e., the workpiece), then stops emitting the first laser and continues to move relative to the silicon carbide crystal (i.e., the workpiece) to the next processing position, and then emits the first laser to process the silicon carbide crystal (i.e., the workpiece), and repeats this process, so that one or more modification marks 300 can be formed inside the workpiece. It should be understood that when implementing step A1, the first laser may process the same position once or multiple times. Step A2: The second laser irradiation modifies the trace to form an absorption trace, so that cracks can be generated inside the workpiece. The absorptivity of the modified trace 300 to the second laser is greater than the absorptivity of the area outside the modified trace to the second laser. The area outside the modified trace refers to the area of ​​the workpiece that has not been processed (i.e., irradiated) by the first laser. For silicon carbide crystals, the area outside the modified trace is basically single-crystalline silicon carbide crystals. As mentioned above, the modified trace 300 contains polycrystalline silicon carbide crystals. The absorptivity of the polycrystalline silicon carbide crystal to the second laser is greater than the absorptivity of the single-crystalline silicon carbide crystal to the second laser. FIG10 is a schematic diagram of the processing effect of the second laser processing silicon carbide crystal provided in an embodiment of the present application. FIG11 is a schematic diagram of a workpiece after the first processing by the first laser and the second laser provided in an embodiment of the present application. FIG12 is a schematic diagram of a workpiece after multiple processing by the first laser and the second laser provided in an embodiment of the present application. Referring to FIG10 to FIG12, the second laser also has a wavelength that is relatively transparent to the silicon carbide crystal (i.e., the workpiece), and can focus on the modified trace 300 produced by the first laser in the silicon carbide crystal (i.e., the workpiece), thereby irradiating the modified trace 300. The depth of focus of the second laser is the same as that of the first laser. The depth of focus is basically the same (there may be errors in actual processing), which is equal to the thickness of the wafer that needs to be peeled off from the silicon carbide crystal. It should be understood that the first laser and the second laser can be emitted by the same laser processing head; the first laser can be emitted by one laser processing head and the second laser can be emitted by another laser processing head. The first laser and the second laser can be generated by the same laser or by different lasers. The first laser and the second laser are different lasers. Specifically, the parameters of the first laser (such as power, pulse width, spot size, central wavelength, repetition frequency and other parameters) are different from the parameters of the second laser (such as power, pulse width, spot size, central wavelength, repetition frequency and other parameters), so that the absorption rate of the second laser by the modified trace is greater than the absorption rate of the second laser by the area outside the modified trace. It should be understood that the parameters of the first laser and the parameters of the second laser may be partially different or completely different. For example, the first laser is a pulse laser with a first pulse width, and the second laser is a pulse laser with a second pulse width, and the second pulse width is greater than the first pulse width; the second laser with the second pulse width irradiates the modified traces, such as moving relative to the silicon carbide crystal (i.e., the workpiece) and irradiating each modified trace, and due to the aforementioned difference in absorption rate, the processing effect of the second laser will be guided to the position of the modified trace of the first laser, and each modified trace 300 absorbs the second laser, and absorption traces 400 will be formed at the position of each modified trace 300 (such as the upper or middle part of the modified trace in the depth direction), thereby forming one or more absorption traces 400 inside the workpiece. The absorption mark 400 is a newly formed modification mark in the workpiece due to the modification mark 300 absorbing the second laser. The absorption mark 400 contains polycrystalline silicon carbide crystals. When a second laser with a relatively high power is used to irradiate the modification mark 300 to improve efficiency, the obtained absorption mark 400 is a modification mark of a larger size, specifically a modification mark with a larger lateral size, or the lateral range of the absorption mark is larger than the lateral range of the modification mark. For example, along the lateral direction of the workpiece (such as the X-axis direction or the Y-axis direction), the lateral size (such as the diameter) of the absorption mark is larger than the lateral size of the modification mark, wherein the lateral direction of the workpiece is perpendicular to the thickness direction of the workpiece; and along the thickness direction of the workpiece (such as the Z-axis direction), the longitudinal size of the absorption mark can be less than, greater than or substantially equal to the longitudinal size of the modification mark, which can be achieved by controlling the parameters (such as the power) of the second laser according to actual needs. Referring to FIG. 11 and FIG. 12 , cracks 500 may appear inside the silicon carbide crystal (i.e., the workpiece) along with the appearance of the absorption mark 400. Even if no cracks are generated when the second laser irradiates the modification mark for the first time, cracks 500 will appear inside the silicon carbide crystal (i.e., the workpiece) when the second laser irradiates the absorption mark again to peel off the workpiece or reduce the thickness of the workpiece. Each crack 500 basically begins to appear at the position of the corresponding modification mark 300 (for example, around the absorption mark 400), with good consistency; wherein, the cracks 500 are generated along the C surface. FIG13 is a schematic diagram of a crack on the C surface provided by an embodiment of the present application. Referring to FIG13 , it should be understood that for silicon carbide, the crack 500 will fluctuate up and down (somewhat like sea waves) with the C surface as the center, and the direction of the crack 500 may also be In various directions (for example, with the modification mark 300 as the center, the cracks are distributed around the center). As mentioned above, there are microcracks near the modification mark 300. When there are multiple modification marks 300, the second laser irradiates the current modification mark to form an absorption mark and generate cracks inside the workpiece. The aforementioned microcracks will change the stress distribution near the tip of the aforementioned crack, thereby guiding the tip of the crack near the current modification mark to develop toward the next modification mark (i.e., the modification mark near the current modification mark). According to the above content, it can be known that the first laser is focused on the inside of the silicon carbide crystal (i.e., the workpiece), so that the absorption rate of the focused area changes, forming a modified mark 300; the second laser irradiates the silicon carbide crystal (i.e., the workpiece), and since the absorption rate of the modified mark 300 to the second laser is greater than the absorption rate of the area outside the modified mark to the second laser, the second laser is absorbed by the modified mark 300 to form an absorption mark 400, thereby causing a crack 500 to be generated inside the workpiece. Due to the aforementioned difference in absorption rate, the processing effect of the second laser can be guided to the modified mark 300 of the first laser. The position can make the crack 500 basically start to generate at the position of the corresponding modification mark 300, and there are micro cracks near the modification mark 300. The aforementioned micro cracks will change the stress distribution near the tip of the crack 500 generated by the second laser irradiation of the current modification mark, thereby guiding the tip of the crack 500 to develop toward the next modification mark 300. In this way, the fluctuation of the crack when the second laser irradiates the workpiece can also be suppressed in the early stage by the aforementioned modification mark, so that it is not easy to have the common undesirable phenomenon of crack fluctuation being amplified by subsequent processing inside the workpiece, and the length of the crack in the longitudinal component can be controlled. In some embodiments, the peak power density of the second laser is outside the peak power density range that can produce nonlinear absorption in the region outside the modified trace alone. Specifically, the second laser energy can be absorbed by the modified trace 300, but can hardly be absorbed by the area outside the modified trace. The area outside the modified trace refers to the area of ​​the workpiece that has not been processed (i.e., irradiated) by the first laser. For silicon carbide crystals, the area outside the modified trace is basically single-crystalline silicon carbide crystals. The first laser is focused on the inside of the silicon carbide crystal (i.e., the workpiece) to form a modified mark inside the workpiece; when the second laser irradiates the modified mark to cause a crack inside the workpiece, since the peak power density of the second laser is outside the peak power density range that can produce nonlinear absorption of the area outside the modified mark alone, even if the focal depth of the second laser fluctuates or the focus swings and irradiates the area outside the modified mark, the area outside the modified mark basically does not absorb the second laser, which can prevent the area outside the modified mark from absorbing the second laser to produce defects and improve the processing quality. FIG14 is a schematic diagram of the laser scanning processing direction and crystal cleavage characteristics provided by an embodiment of the present application. Referring to FIG14, specifically, taking a conductive silicon carbide crystal as an example, the influence of the laser scanning processing direction (i.e., the direction in which the laser moves relative to the workpiece) on the processing effect is discussed. For a conductive silicon carbide crystal, its cleavage plane (i.e., C plane) is inclined at 4° to the upper surface ① (parallel to the first surface 103) and the lower surface ② (parallel to the first surface 103) of the crystal; the intersection direction of the cleavage plane and the upper surface ① is parallel to the crystal. The crystallographic directions are parallel. FIG15 is a schematic diagram of the processing effect when the laser scanning processing direction is parallel or non-parallel to the crystal direction of the silicon carbide crystal provided by an embodiment of the present application. Referring to FIG15, when a laser is used to scan a crystal material, if the laser scanning processing direction D2 is parallel to the crystal material, The crystal direction is parallel, and the crack surface 9C (i.e., the C surface with up and down cracks) generated in the crystal material due to laser scanning is parallel to the laser scanning processing direction D2. Along the laser scanning processing direction D2, the length change of the longitudinal component of the crack is relatively small. Referring to FIG. 15, if the laser scanning processing direction D2' is aligned with the crystal material When the crystal directions are not parallel, the crack surface 9C (i.e., the C surface with up and down cracks) generated in the crystal material due to laser scanning is not parallel to the laser scanning processing direction D2'. The subsequent laser will irradiate the crack surface 9C generated along the laser scanning processing direction D2' but inclined relative to the scanning processing direction D2', causing the crack surface 9C to extend to a higher position. This will cause the length of the longitudinal component of the crack to gradually increase along the laser scanning processing direction, causing the undulation of the peeling surface to increase, resulting in an increase in the roughness of the peeling surface, and further increasing the external force required for peeling. At the same time, more material will need to be removed during later grinding and polishing. In order to prevent the length of the longitudinal component of the crack from fluctuating too much along the laser scanning processing direction, one solution is to make the laser scanning processing direction and the crystal The crystal orientations are completely aligned. However, in this scheme, in order to confirm Crystal orientation requires the addition of additional crystal orientation equipment and has extremely high requirements on the movement accuracy of the processing platform, which makes implementation very difficult. In the laser processing method provided in the embodiment of the present application, there are microcracks near the modified trace 300, and the aforementioned microcracks will change the stress distribution near the tip of the crack 500 generated by the second laser irradiating the current modified trace, even if the scanning processing direction D2 of the second laser is aligned with the direction of the silicon carbide crystal. The microcracks will guide the tip of the crack 500 to develop toward the next modified trace 300, and the length of the longitudinal component of the crack 500 can be controlled, allowing the scanning processing direction D2 of the second laser to be aligned with the direction of the silicon carbide crystal. The crystal orientation has an off-angle (such as the first specified angle), which can reduce the requirements for the crystal orientation ability of the processing process, thereby reducing the difficulty of implementation. A piece of material can be peeled off from the workpiece with less force subsequently, which can reduce the amount of material removed from the crystal material (such as silicon carbide crystal material) during the grinding and polishing process. It can be suitable for eccentrically grown crystal materials (or eccentric crystal materials), and can reduce the requirements for the crystal orientation and crystal uniformity of the crystal material. In summary, in the laser processing method provided in the embodiment of the present application, the second laser can be The crystal direction is at a first specified angle D2 relative to the workpiece (such as an off-axis crystal material) and the second laser irradiates the modified trace 300. The aforementioned first specified angle is greater than 0°. Of course, according to actual conditions, the second laser can also be along other crystal directions (such as The modified trace 300 is irradiated by moving the modified trace 300 relative to the crystal material in a direction of a first specified crystal direction. According to practical results, the aforementioned first specified angle is greater than 0° and less than or equal to 20°, and the length of the longitudinal component of the crack is relatively small. When the aforementioned first specified angle is greater than 20°, the modified traces produced by the first laser inside the silicon carbide crystal will have a relatively reduced guiding effect on the second laser, and the restriction on the length of the longitudinal component of the crack will also be relatively reduced. FIG16 is a schematic diagram of four irradiation areas of the second laser on the workpiece provided in an embodiment of the present application. FIG17 is a schematic diagram of the first irradiation area and the second irradiation area provided in an embodiment of the present application. FIG18 is a schematic diagram of the first irradiation area to the third irradiation area provided in an embodiment of the present application. FIG19 is a schematic diagram of the first irradiation area to the fourth irradiation area provided in an embodiment of the present application. Referring to FIG16 to FIG19, in some embodiments, along the direction D2 in which the second laser moves relative to the workpiece, two adjacent areas irradiated by the focus of the second laser have overlapping parts, so that cracks can be generated in the area between the two absorption marks. The overlapping part of two adjacent areas irradiated by the focus of the second laser is called the overlapping area. Due to the existence of the overlapping area, a new absorption trace will be formed along the moving direction D2 of the second laser, and this newly formed absorption trace is called a diffusion trace. For example, the area irradiated by the focus of the second laser is called the irradiation area (because the position of the focus of the laser may have errors in practice, the aforementioned irradiation area may be the area irradiated by light within the focal depth of the second laser); referring to FIGS. 16 to 19, taking four irradiation areas as an example, the first irradiation area 601 is an absorption trace, the second irradiation area 602 has an overlapping area with the first irradiation area 601, and starting from the overlapping area, a diffusion trace 605 of a certain area is formed in the non-overlapping area of ​​the second irradiation area 602 (the size of the area of ​​the diffusion trace can be determined by setting the parameters of the second laser); referring to FIG. 18, the third The irradiation area 603 has an overlapping area with the second irradiation area 602. Starting from the overlapping area, a diffusion mark 605 of a certain area will be formed in the non-overlapping area of ​​the third irradiation area 603; referring to Figure 19, the fourth irradiation area 604 is an absorption mark. After the second laser irradiation modification mark, a larger modified mark (i.e., absorption mark) will be formed roughly with the modified mark as the center, and the absorption mark will be connected with the diffusion mark 605 of the third irradiation area 603; in this way, along the direction D2 of the second laser movement, a continuous absorption mark can be formed inside the workpiece, so that the workpiece can form a crack along the direction of the second laser movement. In order to achieve overlapping of two adjacent areas irradiated by the focus of the second laser, the second laser may be a pulsed laser, or the overlapping of two adjacent areas irradiated may be achieved by turning on or off the light output. 16 , in some embodiments, along the direction D2 in which the second laser moves relative to the workpiece, there is at least one region irradiated by the focus of the second laser between the two absorption marks, that is, the two absorption marks 400 are separated by at least one irradiated region. During the process of the second laser irradiation modifying the mark 300 to form the absorption mark 400, relatively large energy absorption will occur. By separating the two absorption marks 400 through at least one irradiation area, the phenomenon of ablation or vaporization can be reduced, the damage to the inside of the workpiece can be reduced, and the processing quality can be improved. FIG20 is a schematic diagram of the distribution of modification marks provided by an embodiment of the present application. Referring to FIG20 , in some embodiments, along the direction D1 in which the first laser moves relative to the workpiece, the gap distance S between two adjacent modification marks 300 is smaller than the spot size of the focus of the second laser, which can increase the probability of the second laser irradiating the modification marks 300. Referring to Figure 12, in some embodiments, a first laser moves relative to the workpiece along a first path and is focused on the interior of the workpiece to form a modification mark inside the workpiece; a second laser moves relative to the workpiece along the first path and the second laser irradiates the modification mark to form an absorption mark, so that cracks can be generated inside the workpiece. The first laser and the second laser move relative to the workpiece along the same path (ie, the first path) and irradiate the workpiece, which can simplify parameter settings of the equipment and improve efficiency. Referring to FIG. 12 , in some embodiments, the second laser is directed along a specified direction (such as the Y-axis direction or The second laser switches and moves relative to the workpiece in a direction parallel to the specified direction and the second laser irradiates another part of the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece. Specifically, the second laser processes the workpiece in a row-by-row scanning manner, irradiating the modified traces at different positions. Figure 21 is a schematic diagram of the interconnected cracks of adjacent C surfaces of the workpiece provided by an embodiment of the present application. Referring to Figures 12 and 21, the position d of the focus of the second laser is basically unchanged, and the irradiation area of ​​each row corresponds to a C surface. The C surfaces corresponding to the irradiation areas of two adjacent rows are basically parallel and have a height difference in the height direction of the workpiece; the second laser processes the workpiece in a row-by-row scanning manner, and as the cracks extend along the C surface, the cracks of adjacent C surfaces can be connected together, for example: referring to Figures 12 and 21, the cracks of C surface 1C are connected to the cracks of C surface 2C, the cracks of C surface 2C are connected to the cracks of C surface 3C, the cracks of C surface 3C are connected to the cracks of C surface 4C, the cracks of C surface 4C are connected to the cracks of C surface 5C, and the cracks of C surface 5C are connected to the cracks of C surface 6C to form a peeling surface; this can achieve peeling of the workpiece or thinning the thickness of the workpiece. When the longitudinal size of the crack is controlled, the TTV (Total Thickness Variation) of the wafer peeled from the silicon carbide crystal (also called the peeling layer) will be reduced. When the TTV of the peeling layer is reduced, the external force required for peeling will also be reduced, and less material removal is required to grind the rough peeling surface to a flat surface. In some embodiments, the peak power density of the second laser is within a peak power density range that can produce nonlinear absorption in a region outside the modified trace alone. Since the absorption rate of the modified trace to the second laser is greater than the absorption rate of the area outside the modified trace to the second laser, although both the modified trace and the area outside the modified trace can produce nonlinear absorption of the second laser, the second laser will be absorbed by the modified trace first, which can to a certain extent avoid damage to the area outside the modified trace due to absorption of the second laser, thereby protecting the workpiece. In some embodiments, the second laser irradiates the modified mark multiple times in an intermittent manner to generate cracks inside the workpiece. As mentioned above, the second laser irradiation on the modified trace will form an absorption trace, and with the appearance of the absorption trace, cracks may appear inside the silicon carbide crystal (i.e., the workpiece). The second laser irradiates the modified trace multiple times in an intermittent manner, and the cracks around the same modified trace will grow to a certain length each time the second laser is irradiated, which can make the crack gradually grow to a specified length, and can prevent the modified trace from absorbing too much energy at one time, causing the crack to grow violently and exceed the specified length, and can better control the longitudinal size of the crack and improve the processing accuracy. The second laser irradiates the modified trace multiple times in an intermittent manner to generate cracks inside the workpiece. This can be achieved by: multiple pulses of the second laser successively irradiate the modified trace to generate cracks inside the workpiece. Specifically, the second laser may be a pulsed laser, and a plurality of pulsed lasers may be sequentially irradiated on the modified trace at a certain interval, so that the crack may gradually grow to a specified length. As mentioned above, the second laser irradiation of the modified trace will cause cracks to appear inside the silicon carbide crystal (i.e., the workpiece). Since the second laser energy can be absorbed by the modified trace 300, but basically cannot be absorbed by the area outside the modified trace, the second laser irradiates the modified trace multiple times in an intermittent manner. Referring to Figures 11 and 12, the cracks around the same modified trace will grow to a certain length each time the second laser is irradiated, which can make the cracks gradually grow to a specified length, can prevent the modified trace from absorbing too much energy at one time, causing the cracks to grow violently and exceed the specified length, can better control the longitudinal size of the cracks, and can improve the processing accuracy. The second laser irradiates the modified trace multiple times in an intermittent manner so that cracks can be generated inside the workpiece. It can also be achieved by moving the second laser relative to the workpiece along the same path multiple times and irradiating the modified trace so that cracks can be generated inside the workpiece. Specifically, after the second laser completes the first irradiation of the modified trace along the specified path, it returns to irradiate the modified trace for the Nth time (N is an integer greater than 1) along the specified path, so that the crack can gradually grow to the specified length. The laser processing method provided in the embodiments of the present application can control the longitudinal size of the crack, effectively reduce the fluctuation of the peeling surface caused by the eccentric growth of the crystal material (such as silicon carbide crystal material) (TTV, Total Thickness Variation, also known as total thickness deviation), and obtain a smoother peeling surface. The smooth peeling surface can be peeled with less force; at the same time, the laser damage layer of the smooth peeling surface is also smaller, which can reduce the amount of material removed from the crystal material (such as silicon carbide crystal material) during the grinding and polishing process; the requirements for the crystal orientation and crystal uniformity of the crystal material (such as silicon carbide crystal material) are relatively low, which is more conducive to implementation in the industrialization process, can improve production efficiency and reduce costs, and can be applied to the slicing of silicon carbide ingots and the thinning of silicon carbide devices. The laser processing method provided in the embodiment of the present application can also prevent the area outside the modified trace from absorbing the second laser to generate Cracks can improve processing quality. Referring to Figures 5 and 6, the first surface 103 of the eccentric silicon carbide crystal is not parallel to the C-plane (0001), and the first surface 103 forms a small angle α with the C-plane (0001), α is usually 4°, and the first surface 103 of other eccentric crystal materials (such as gallium nitride) is also not parallel to the C-plane (0001). Axis 201 represents an imaginary straight line perpendicular to the first surface 103 of the crystal. Referring to Figure 6, for the eccentric silicon carbide crystal, the axis 201 presents a 4° inclination angle α with the C-axis. When a cleavage crack is generated inside the eccentric silicon carbide crystal, the crack propagates along the C-plane (0001), and the peeling surface formed by the crack propagation will eventually present a 4° inclination angle with the first surface 103. However, the generation of cracks has a certain randomness, and crack dislocation may occur, which makes it difficult for cracks on adjacent C-planes to connect together. How the above-mentioned laser processing method solves the above-mentioned technical problems is specifically described. The above-mentioned step A1 (i.e., the first laser is focused on the inside of the workpiece to form one or more modification marks inside the workpiece) may specifically include: the first laser moves relative to the workpiece along a first path and is focused on the inside of the workpiece to form modification marks inside the workpiece. FIG22 is a schematic diagram of the processing effect of a first laser processing a silicon carbide crystal along a first processing path provided by an embodiment of the present application. Referring to FIG9, FIG10 and FIG22, the first laser has a wavelength that is relatively transparent to the silicon carbide crystal (i.e., the workpiece). The first laser moves relative to the silicon carbide crystal along the first path 301 and focuses on the inside of the silicon carbide crystal, forming a modified trace 300 inside the silicon carbide crystal, and the number of the modified traces 300 can be one or more; wherein the depth of focus is equal to the thickness of the wafer that needs to be peeled off from the silicon carbide crystal. The first laser is focused on the silicon carbide crystal to achieve modification, and a modification mark 300 is formed inside the workpiece. For example, the first laser is focused on the silicon carbide crystal, so that the single-crystalline silicon carbide crystal is transformed into a polycrystalline silicon carbide crystal. Of course, when the first laser is focused on the silicon carbide crystal, gasification or sublimation may occur; therefore, the modification mark contains polycrystalline silicon carbide crystals. The modification mark 300 can be point-shaped or line-shaped, such as points spaced apart along the direction in which the first laser moves or a continuous line (such as a straight line, a circular line, or a spiral) along the direction in which the first laser moves. Along with the formation of the modification mark 300 , micro cracks exist near the modification mark 300 . The micro cracks are tiny cracks that are invisible to the naked eye. It should be understood that by setting the power, pulse width, spot size, central wavelength, repetition frequency and other parameters of the first laser, the first laser can be focused on the silicon carbide crystal to modify the silicon carbide crystal. For example, the pulsed laser of the first pulse width moves relative to the silicon carbide crystal (i.e., the workpiece) and focuses on the inside of the silicon carbide crystal (i.e., the workpiece), so that the silicon carbide crystal is modified. In practical applications, the laser processing head may emit the first laser. The laser processing head moves along the first path 301 relative to the silicon carbide crystal (i.e., the workpiece), and the laser processing head emits the first laser; for example, the laser processing head moves along the first path 301 relative to the silicon carbide crystal (i.e., the workpiece), and emits the first laser to process the silicon carbide crystal (i.e., the workpiece); or, After the laser processing head moves to a processing position relative to the silicon carbide crystal (i.e., the workpiece) along the first path 301, it emits a first laser to process the silicon carbide crystal (i.e., the workpiece), then stops emitting the first laser and continues to move to the next processing position relative to the silicon carbide crystal (i.e., the workpiece) along the first path, and then emits the first laser again to process the silicon carbide crystal (i.e., the workpiece), and repeats this process; in this way, the first laser is moved relative to the silicon carbide crystal (i.e., the workpiece) along the first path 301. Figure 23 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a first processing path using a first laser according to another embodiment of the present application. Figure 24 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a first processing path using a first laser according to another embodiment of the present application. Figure 25 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a first processing path using a first laser according to another embodiment of the present application. Referring to Figures 23 to 25, the aforementioned first path may be a straight path, a concentric circle path, or a spiral path. Referring to Figure 8, when the first path 301 is a straight path, the straight path may be parallel to the first positioning surface 101, or may be non-parallel to the first positioning surface 101. The aforementioned modification traces may be points distributed at intervals along the first path, or may be continuous lines (such as straight lines, circular lines or spirals) along the first path. In some embodiments, the first laser moves relative to the workpiece along the first path 301 and focuses on the inside of the workpiece. After completing the first processing along the first path, the first laser changes line and moves relative to the workpiece along the first path and continues to focus on the inside of the workpiece (i.e., line-by-line scanning processing) to form modification marks located in different lines inside the workpiece, that is, to form multiple lines of modification marks inside the workpiece. FIG26 shows the effect of the modified traces being distributed in the Y-axis direction according to the set spacing. FIG27 shows a schematic diagram of the modified traces in the X-axis direction. For example, referring to FIG26 and FIG27, after completing the first scanning process along the first path 301, the first laser moves a specified distance in a direction perpendicular to the first path 301 to achieve line change, so that each modified trace is arranged at a certain spacing to form multiple rows of modified traces 300; wherein the line spacing can be 50 to 500 μm. It should be understood that when implementing step A1, the first laser may process the same position once or multiple times. The above-mentioned step A2 (i.e., the second laser irradiates the modified trace to form an absorption trace so that cracks can be generated inside the workpiece) can specifically include: the second laser moves relative to the workpiece along the second path, and the second laser irradiates the modified trace and continues to irradiate different modified traces along the second path in turn, so that cracks can be generated inside the workpiece along the C-surface. FIG28 is a schematic diagram of the processing effect of processing a silicon carbide crystal along a second processing path by a second laser provided in an embodiment of the present application. Referring to FIG10 , FIG12 and FIG28 , the second laser also has a wavelength that is relatively transparent to the silicon carbide crystal (i.e., the workpiece), and can be focused on the modified trace 300 produced by the first laser in the silicon carbide crystal (i.e., the workpiece). The depth of the second laser focus is substantially the same as the depth of the first laser focus (there may be errors in actual processing), which is equal to the thickness of the wafer that needs to be peeled off from the silicon carbide crystal. The first laser and the second laser are different lasers. Specifically, the parameters of the first laser (such as power, pulse width, etc.) The parameters of the first laser (such as power, pulse width, spot size, central wavelength, repetition frequency, etc.) are different from those of the second laser (such as power, pulse width, spot size, central wavelength, repetition frequency, etc.), so that the absorption rate of the modified trace to the second laser is greater than the absorption rate of the area outside the modified trace to the second laser. The area outside the modified trace refers to the area of ​​the workpiece that has not been processed (i.e. irradiated) by the first laser. For silicon carbide crystal, the area outside the modified trace is basically single-crystalline silicon carbide crystal. As mentioned above, the modified trace 300 is basically polycrystalline silicon carbide crystal. The absorption rate of the polycrystalline silicon carbide crystal to the second laser is greater than the absorption rate of the single-crystalline silicon carbide crystal to the second laser. It should be understood that the parameters of the first laser and the parameters of the second laser may be partially different or completely different. For example, the first laser is a pulse laser with a first pulse width, and the second laser is a pulse laser with a second pulse width, and the second pulse width is greater than the first pulse width; the second laser with the second pulse width irradiates the modified traces, such as moving along the second path 401 relative to the silicon carbide crystal (i.e., the workpiece) and irradiating each modified trace. Due to the aforementioned difference in absorption rate, the processing effect of the second laser will be guided to the position of the modified trace of the first laser, and each modified trace 300 absorbs the second laser, and absorption traces 400 will be formed at the position of each modified trace 300 (such as the upper or middle part of the modified trace in the depth direction), thereby forming one or more absorption traces 400 inside the workpiece. The absorption mark 400 is a newly formed modification mark in the workpiece due to the modification mark 300 absorbing the second laser. The absorption mark 400 contains polycrystalline silicon carbide crystals. When a second laser with a relatively high power is used to irradiate the modification mark 300 to improve efficiency, the obtained absorption mark 400 is a modification mark of a larger size, specifically a modification mark with a larger lateral size, or the lateral range of the absorption mark is larger than the lateral range of the modification mark. For example, along the lateral direction of the workpiece (such as the X-axis direction or the Y-axis direction), the lateral size (such as the diameter) of the absorption mark is larger than the lateral size of the modification mark, wherein the lateral direction of the workpiece is perpendicular to the thickness direction of the workpiece; and along the thickness direction of the workpiece (such as the Z-axis direction), the longitudinal size of the absorption mark can be less than, greater than or substantially equal to the longitudinal size of the modification mark, which can be achieved by controlling the parameters (such as the power) of the second laser according to actual needs. In some embodiments, the second laser moves relative to the workpiece along the second path 401 , and the second laser irradiates the modified trace 300 to form the absorption trace 400 and continues to irradiate different modified traces 300 along the second path 401 to form the absorption trace 400 . Specifically, after completing the first scanning process along the second path 401, the second laser moves a specified distance in a direction perpendicular to the second path 401 to achieve a row change, and continues to irradiate different modified traces 300 along the second path 401 to form multiple rows of absorption traces 400, and the absorption traces 400 of adjacent rows are arranged at a certain interval. The second path 401 can be a straight path or a broken line path. Referring to FIG. 12 , cracks 500 may appear inside the silicon carbide crystal (i.e., the workpiece) along with the appearance of the absorption mark. Even if no cracks are generated when the second laser irradiates the modification mark for the first time, cracks 500 may appear inside the silicon carbide crystal (i.e., the workpiece) when the second laser irradiates the absorption mark again to peel off the workpiece or reduce the thickness of the workpiece. Each crack 500 basically begins to appear at the position of the corresponding modification mark 300 (for example, around the absorption mark 400), with The crack 500 is generated along the C-plane, and specifically can be formed into cracks in different columns. Of course, the absorption trace is optional, and the crack 500 can be directly generated by the second laser irradiation modification trace 300. Referring to FIG. 13 , it should be understood that for silicon carbide, the crack 500 will fluctuate up and down (somewhat like ocean waves) with the C-plane as the center, and the crack 500 may also be distributed in various directions (for example, with the modified trace 300 as the center, and the cracks are distributed around the center). It should be understood that the first laser and the second laser can be emitted by the same laser processing head; the first laser can be emitted by one laser processing head and the second laser can be emitted by another laser processing head. The first laser and the second laser can be generated by the same laser or by different lasers. According to the above content, it can be known that the first laser moves relative to the silicon carbide crystal (i.e., the workpiece) along the first path and focuses on the inside of the silicon carbide crystal (i.e., the workpiece) to form a modified trace; the second laser moves relative to the silicon carbide crystal (i.e., the workpiece) along the second path and irradiates the modified trace and continues to irradiate different modified traces along the second path. The second laser is absorbed by the modified trace, so that the inside of the silicon carbide crystal (i.e., the workpiece) can produce cracks along the C surface. Since the first path intersects with the second path, an overlap is formed inside the workpiece. The second laser moves relative to the silicon carbide crystal (i.e., the workpiece) along the direction in which the second laser moves. In the direction, cracks will be generated at the first overlapping part of adjacent columns starting from the position of the first path, which is conducive to making the cracks in adjacent columns easily connected together (for example: referring to Figure 12, the crack on C-surface 1C is connected to the crack on C-surface 2C, the crack on C-surface 2C is connected to the crack on C-surface 3C, the crack on C-surface 3C is connected to the crack on C-surface 4C, the crack on C-surface 4C is connected to the crack on C-surface 5C, and the crack on C-surface 5C is connected to the crack on C-surface 6C), which can reduce the misalignment of cracks in adjacent columns, thereby improving the consistency of the cracks. The workpiece The crystal direction is called the first crystal direction. Crystal orientation and the C-plane of the workpiece (i.e. (0001) crystal plane), The normal plane of the crystal direction (i.e. The crystal plane is perpendicular to the C plane. The second laser in step A2 moves relative to the workpiece along the second path and irradiates the modified trace with the second laser, which may specifically include: the second laser moves relative to the workpiece along the second path and irradiates the modified trace with the first crystal direction (i.e. The second laser irradiates the modified trace 300. Accordingly, the second laser also moves in the direction of the first crystal direction (i.e., the first crystal direction) at a first specified angle relative to the workpiece. The different modified traces 300 are continuously irradiated in a direction with a first specified angle (in the crystal direction). Referring to FIG14 , specifically, taking a conductive silicon carbide crystal as an example, the influence of the laser scanning processing direction (i.e., the direction in which the laser moves relative to the workpiece) on the processing effect is discussed. For a conductive silicon carbide crystal, its cleavage plane (i.e., C plane) is inclined 4° to the upper surface ① (parallel to the first surface 103) and the lower surface ② (parallel to the first surface 103) of the crystal; the intersection direction of the cleavage plane and the upper surface ① is parallel to the crystal's The crystallographic directions are parallel. 15, when a laser is used to scan a crystal material, if the laser scanning processing direction D2 is aligned with the crystal material, The crystal direction is parallel, and the crack surface 9C (i.e., the C surface with up and down cracks) generated in the crystal material due to laser scanning is parallel to the laser scanning processing direction D2. Along the laser scanning processing direction D2, the length change of the longitudinal component of the crack is relatively small. Referring to FIG. 15, if the laser scanning processing direction D2' is aligned with the crystal material When the crystal directions are not parallel, the crack surface 9C (i.e., the C surface with up and down cracks) generated in the crystal material due to laser scanning is not parallel to the laser scanning processing direction D2'. The subsequent laser will irradiate the crack surface 9C generated along the laser scanning processing direction D2' but inclined relative to the scanning processing direction D2', causing the crack surface 9C to extend to a higher position. This will cause the longitudinal size of the crack to gradually increase along the laser scanning processing direction, causing the undulation of the peeling surface to increase, resulting in an increase in the roughness of the peeling surface, and further increasing the external force required for peeling. At the same time, more material will need to be removed during later grinding and polishing. In order to prevent the length of the longitudinal component of the crack from fluctuating too much along the laser scanning processing direction, one solution is to make the laser scanning processing direction and the crystal The crystal orientations are completely aligned. However, in this scheme, in order to confirm Crystal orientation requires the addition of additional crystal orientation equipment and has extremely high requirements on the movement accuracy of the processing platform, which makes implementation very difficult. Referring to Figures 12 and 28, in the laser processing method provided in the embodiment of the present application, the first laser moves relative to the workpiece along the first path and focuses on the inside of the workpiece, the first laser changes line and continues to focus on the inside of the workpiece along the first path, and forms multiple lines of modified marks 300 inside the workpiece, and the second laser irradiates the silicon carbide crystal (i.e., the workpiece). Since the absorption rate of the aforementioned modified mark 300 to the second laser is greater than the absorption rate of the area outside the modified mark to the second laser, the second laser is absorbed by the aforementioned modified mark 300 to form an absorption mark 400, thereby allowing a crack 500 to be generated inside the workpiece. Due to the aforementioned difference in absorption rate, the processing effect of the second laser can be guided to the position of the modified mark 300 of the first laser, so that the crack 500 can be basically generated at the corresponding position of the modified mark 300, and there are microcracks near the modified mark. The aforementioned microcracks will change the stress distribution near the tip of the crack generated by the second laser irradiating the current modified mark, even if the scanning processing direction D2 of the second laser is different from the direction of the silicon carbide crystal. The crystal direction has an angle (such as the first specified angle), and the aforementioned microcrack will guide the tip of the crack to develop toward the next modified trace, which can control the length of the crack in the longitudinal direction and allow the scanning processing direction of the second laser to be aligned with the direction of the silicon carbide crystal. The crystal orientation has an off-angle (such as the first specified angle), which can reduce the requirements for the crystal orientation ability of the processing process, thereby reducing the difficulty of implementation. A piece of material can be peeled off from the workpiece with less force subsequently, which can reduce the amount of material removed from the crystal material (such as silicon carbide crystal material) during the grinding and polishing process. It can be suitable for eccentrically grown crystal materials (or eccentric crystal materials), and can reduce the requirements for the crystal orientation and crystal uniformity of the crystal material. According to practical results, the first specified angle is greater than 0° and less than or equal to 20°, and the longitudinal size of the crack is relatively When the aforementioned first specified angle is greater than 20°, the guiding effect of the modified traces produced by the first laser inside the silicon carbide crystal on the second laser will be relatively reduced, and the restriction on the length of the longitudinal component of the crack will also be relatively reduced. Of course, according to the actual situation, the second laser can also be along other crystal directions (such as The modified trace 300 is irradiated by moving the modified trace 300 relative to the crystal material in a direction of a first specified crystal direction. Referring to FIG. 12 and FIG. 28 , when the first path 301 is perpendicular to the second path 401, for example, the first path 301 and the second path 401 are straight paths, the second path 401 overlaps with the modified trace 300, and a grid-like processing trace is formed inside the silicon carbide crystal (i.e., the workpiece). The grid has many overlaps and the overlaps are located in various directions, and the length of the longitudinal component of the crack can be controlled at various positions and in various directions, and the length of the longitudinal component of the crack can be made smaller along the scanning processing direction of the laser, which can better improve the processing quality. In addition, referring to Figures 12 and 28, when the first path 301 is perpendicular to the second path 401, the first overlap of adjacent columns can be directly opposite to the direction perpendicular to the movement of the second laser (the remaining overlaps are also directly opposite one by one). The cracks caused by the modification of the crystal material due to laser scanning are mainly located on both sides of the laser scanning processing direction. The cracks generated at the first overlap of adjacent columns can also tend to be more directly opposite to the direction perpendicular to the movement of the second laser, making it easier for the cracks in adjacent columns to connect together. Of course, the second laser can also be parallel to the first crystal direction (i.e. The workpiece moves relative to the direction of the first crystal direction and the second laser irradiates the modified trace. Different modified traces 300 are continuously irradiated in the direction of the crystal direction. As mentioned above, the crystal material has a first positioning surface 101, and the first positioning surface 101 is used to determine the crystal direction of the crystal material. For a general crystal material (such as a cylindrical silicon carbide ingot), the first positioning surface 101 is perpendicular to the first crystal direction (i.e. The first positioning surface 101 is perpendicular to the second positioning surface 102. The above step A1 (i.e. the first laser moves relative to the workpiece along the first path and focuses on the inside of the workpiece) may specifically include: the first laser moves relative to the workpiece along the direction forming the second specified angle with the first positioning surface 101 and focuses on the inside of the workpiece. Correspondingly, after the first laser changes its line, it continues to focus on the inside of the workpiece along the direction forming the second specified angle with the first positioning surface 101. It should be understood that the size of the second specified angle only needs to make the first path intersect the second path. The first positioning surface 101 is a solid surface of a crystal material (such as a cylindrical silicon carbide ingot). The scanning processing direction of the first laser is determined with reference to the first positioning surface 101, which is easier to operate in practical applications. As mentioned above, the crystal material also has a second positioning surface 102, and the second positioning surface 102 is used to determine the crystal orientation of the crystal material. The second positioning surface 102 is parallel to the first crystal direction (ie crystal orientation). The aforementioned second laser moves relative to the workpiece along a direction forming a first specified angle with the first crystal direction and irradiates the modified trace by the second laser, specifically including: the second laser moves relative to the workpiece along a direction forming a first specified angle with the second positioning surface 102 and irradiates the modified trace 300. Correspondingly, after the second laser is switched, it continues to irradiate different modified traces 300 along the direction forming the first specified angle with the second positioning surface 102. because The crystal direction is parallel to the second positioning surface 102, and therefore, The direction of the crystal orientation at the first specified angle is the direction at the first specified angle with the second positioning surface 102. The first specified angle is greater than 0° and less than or equal to 20°. The second positioning surface 102 is a solid surface of a crystal material (such as a cylindrical silicon carbide ingot). The scanning processing direction of the second laser is determined with reference to the second positioning surface 102, which is easier to operate in practical applications. The above step A1 (i.e., the first laser moves relative to the workpiece along the first path and focuses on the inside of the workpiece to form a modified trace inside the workpiece) can specifically include: the first laser moves intermittently relative to the workpiece along the first path and focuses on the inside of the workpiece to form spaced modified points inside the workpiece or to form overlapping modified points inside the workpiece. The first laser intermittently moves relative to the workpiece along the first path 301 and focuses on the inside of the workpiece. The modified traces formed inside the workpiece are distributed along the first path 301. The modified traces can be multiple independent points or multiple overlapping points. When the modified traces are multiple independent points, each point is arranged at a small spacing along the first path, usually <10μm. For example, the laser processing head moves relative to the silicon carbide crystal (i.e., the workpiece) along the first path 301 to the processing position and emits the first laser, and the first laser is focused on the inside of the silicon carbide crystal (i.e., the workpiece) to process the silicon carbide crystal (i.e., the workpiece); after the processing is completed at the current processing position, the laser processing head stops emitting the first laser and continues to move relative to the silicon carbide crystal (i.e., the workpiece) along the first path to the next processing position to be processed (there is a gap between two adjacent processing positions), and then emits the first laser to process the silicon carbide crystal (i.e., the workpiece), and so on and so forth, a plurality of points distributed along the first path 301 (there is a gap between two adjacent points) can be formed inside the silicon carbide crystal (i.e., the workpiece), that is, the formed modification traces are a plurality of independent points. FIG. 29 is a schematic diagram of modification traces provided by another embodiment of the present application. Referring to FIG. 29, when two adjacent processing positions have partial overlap, the formed modification traces are a plurality of overlapping points; specifically, N (N is an integer greater than or equal to 2) overlapping points are grouped together, and there is a gap between each group of points. The above-mentioned step A1 (i.e., the first laser moves relative to the workpiece along the first path and focuses on the inside of the workpiece to form a modification mark inside the workpiece) may specifically include: the first laser continuously moves relative to the workpiece along the first path and focuses on the inside of the workpiece to form a modification line inside the workpiece. For example, the laser processing head moves relative to the silicon carbide crystal (i.e., the workpiece) along a first path and emits a first laser, the first laser is focused on the interior of the silicon carbide crystal (i.e., the workpiece) and processes the silicon carbide crystal (i.e., the workpiece) along the first path, and a linear modified structure (i.e., a modified line) distributed along the first path is formed inside the silicon carbide crystal (i.e., the workpiece). The laser processing method provided in the embodiments of the present application can improve the consistency of cracks, effectively reduce the fluctuations (TTV, Total Thickness Variation) of the peeling surface caused by the eccentric growth of the crystal material (such as silicon carbide crystal material), and obtain a smoother peeling surface. The smooth peeling surface can be peeled with less force; at the same time, the laser damage layer of the smooth peeling surface is also smaller, which can reduce the amount of material removed from the crystal material (such as silicon carbide crystal material) during the grinding and polishing process; the requirements for the crystal orientation and crystal uniformity of the crystal material (such as silicon carbide crystal material) are relatively low, which is more conducive to implementation in the industrialization process, can improve production efficiency and reduce costs, and can be applied to the slicing of silicon carbide ingots and the thinning of silicon carbide devices. Corresponding to the method described in the above embodiment, FIG30 shows a structural block diagram of the laser processing device provided in the embodiment of the present application. For the sake of convenience of explanation, only the part related to the embodiment of the present application is shown. 30 , the apparatus includes a first processing module 1A and a second processing module 2A. The first processing module 1A is used to focus the first laser on the inside of the workpiece to form one or more modification marks inside the workpiece. The second processing module 2A is used to: make the second laser irradiation modification mark form an absorption mark, so that cracks can be generated inside the workpiece. The absorption rate of the second laser beam in the modified trace is greater than the absorption rate of the second laser beam in the area outside the modified trace. In some embodiments, the first processing module 1A is specifically used to: move the first laser relative to the workpiece along a first path and focus on the inside of the workpiece to form a modification mark inside the workpiece. The second processing module 2A is specifically used to move the second laser relative to the workpiece along the second path, and the second laser irradiates the modified trace to form an absorption trace and continues to irradiate different modified traces along the second path to form absorption traces, so that cracks can be generated inside the workpiece along the C surface. The first laser and the second laser are different lasers. The first path intersects the second path. In some embodiments, the workpiece further has a first positioning surface, which is perpendicular to the crystal direction of the workpiece; the first processing module 1A is specifically used to move the first laser relative to the workpiece along a direction forming a second specified angle with the first positioning surface. In some embodiments, the workpiece further has a second positioning surface, which is parallel to the crystal direction of the workpiece; the second processing module 2A is specifically used to: move the second laser relative to the workpiece along a direction forming a first specified angle with the second positioning surface and irradiate the modified trace with the second laser. In some embodiments, the peak power density of the second laser is outside the peak power density range that can produce nonlinear absorption in the region outside the modified trace alone. In some embodiments, the second processing module 2A is specifically used to: make the second laser along The crystal direction moves relative to the workpiece in a direction of a first specified angle and a second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece. In some embodiments, the first processing module 1A is specifically used to move the first laser relative to the workpiece and focus the first laser on the inside of the workpiece to form one or more modification marks inside the workpiece. In some embodiments, the second processing module 2A is specifically used to: move the second laser relative to the workpiece and irradiate the second laser to modify the traces to form absorption traces, so that cracks can be generated inside the workpiece. In some embodiments, the first processing module 1A is specifically used to: move the first laser relative to the workpiece along a first path and focus on the inside of the workpiece to form one or more modification marks inside the workpiece. The second processing module 2A is specifically used to: move the second laser relative to the workpiece along the first path and irradiate the modification trace with the second laser to form an absorption trace, so that cracks can be generated inside the workpiece. In some embodiments, the second processing module 2A is specifically used to: move the second laser relative to the workpiece in a specified direction and irradiate a portion of the modified trace to form an absorption trace, change the second laser and move relative to the workpiece in a direction parallel to the specified direction and irradiate another portion of the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece. In some embodiments, the second processing module 2A is specifically used to: allow the second laser to intermittently irradiate the modification trace multiple times to form an absorption trace, so that cracks can be generated inside the workpiece. In some embodiments, the second processing module 2A is specifically used to: allow multiple pulses of the second laser to successively irradiate the modification marks to form absorption marks, so that cracks can be generated inside the workpiece. In some embodiments, the second processing module 2A is specifically used to: move the second laser multiple times along the same path relative to the workpiece and irradiate the second laser to modify the traces to form absorption traces, so that cracks can be generated inside the workpiece. It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here. The embodiments of the present application also provide a device, which is manufactured by the laser processing method provided by any of the above embodiments. The aforementioned device may be a silicon carbide wafer or a silicon carbide device. The aforementioned device has a modification trace and an absorption trace; the range of the absorption trace is larger than the range of the modification trace, for example: along the lateral direction of the aforementioned device, the lateral dimension of the absorption trace is larger than the lateral dimension of the modification trace; along the height direction of the aforementioned device, the longitudinal dimension of the absorption trace is substantially equal to the longitudinal dimension of the modification trace. The processed surface of the aforementioned device may be formed with intersecting processing traces (such as grid-shaped processing traces). The embodiment of the present application also provides a device, which may be a silicon carbide wafer or a silicon carbide device. There are modification marks 300, absorption marks 400 and cracks 500. The modified trace 300 is formed by focusing the first laser on the inside of the workpiece. The crack 500 is formed inside the workpiece when the second laser irradiates the modified mark 300 to form the absorption mark 400. The crack 500 may be located around the absorption mark 400. As mentioned above, the absorption rate of the second laser beam by the modified trace 300 is greater than the absorption rate of the second laser beam by the area outside the modified trace 300. FIG31 is a schematic diagram of the structure of a processing device provided in an embodiment of the present application. As shown in FIG31 , the processing device 23 of this embodiment includes: at least one processor 230 (only one is shown in FIG31 ), a memory 231, and a computer program 232 stored in the memory 231 and executable on at least one processor 230; when the processor 230 executes the computer program 232, the steps in any of the above-mentioned method embodiments are implemented. The processing device 23 may include, but is not limited to, a processor 230 and a memory 231. Those skilled in the art will appreciate that FIG31 is merely an example of a processing device and does not constitute a limitation on the processing device, and may include more or fewer components than shown in the figure, or a combination of certain components, or different components, such as input and output devices, network access devices, buses, etc. The processor 230 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. In some embodiments, the memory 231 may be an internal storage unit of the processing device 23, such as a hard disk or memory of the processing device. In other embodiments, the memory 231 may also be an external storage device of the processing device, such as a plug-in hard disk equipped on the processing device, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. Further, the memory 231 may also include both an internal storage unit of the processing device and an external storage device. The memory 231 is used to store an operating system, an application program, a boot loader (Boot Loader), data, and other programs, such as program codes of computer programs, etc. The memory 231 may also be used to temporarily store data that has been output or is to be output. Exemplarily, the computer program 232 may be divided into one or more modules / units, one or more modules / units are stored in the memory 231, and are executed by the processor 230 to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution process of the computer program 232 in the processing device 23. FIG32 is a schematic diagram of the structure of a crystal material stripping device provided in an embodiment of the present application. The embodiment further provides a crystal material stripping device for stripping a crystal material or reducing the thickness of a crystal material. The crystal material may be silicon carbide or gallium nitride. 32 , the crystal material stripping device provided in the embodiment of the present application includes an irradiation unit 241 and a stripping unit 242 . The irradiation unit 241 is used to emit a first laser to focus on the inside of the crystal material to form one or more modified marks 300 inside the crystal material, and to emit a second laser to irradiate the modified marks 300 to form absorption marks 400, so that cracks 500 can be generated inside the crystal material. The absorption rate of the modified marks 300 to the second laser is greater than the absorption rate of the area outside the modified marks to the second laser. The stripping unit 242 is used to strip a wafer from the crystal material with the crack 500 as the starting point, thereby stripping the crystal material or reducing the thickness of the crystal material. The wafer may be a wafer or a thin sheet of waste material generated to reduce the thickness of the crystal material. In some embodiments, the irradiation unit 241 is specifically used to emit a first laser that moves relative to the crystal material along a first path and focuses on the interior of the crystal material to form a modification mark 300 inside the crystal material, and emit a second laser that moves relative to the crystal material along a second path, and the second laser irradiates the modification mark 300 to form an absorption mark 400 and continues to irradiate different modification marks along the second path to form an absorption mark 400, so that a crack 500 can be generated along the C-plane inside the crystal material. The first laser and the second laser are different lasers; the first path intersects with the second path. The stripping unit 242 is specifically used to strip a wafer from the crystal material with the crack 500 as a starting point, thereby stripping the crystal material or reducing the thickness of the crystal material. The irradiation unit 241 may include the first processing module 1A and the second processing module 2A. It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here. If the aforementioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all of the above-mentioned embodiments. The whole or part of the process can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium; when the computer program is executed by the processor, the steps of each of the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable media include: any entity or device that can carry computer program code to a device / terminal device, recording medium, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. For example, USB flash drive, mobile hard disk, magnetic disk or optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals. An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented. An embodiment of the present application provides a computer program product. When the computer program product runs on a terminal device, the terminal device can implement the steps in the above-mentioned various method embodiments. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application. In the embodiments provided in the present application, it should be understood that the disclosed devices / equipment and methods can be implemented in other ways. For example, the device / equipment embodiments described above are merely schematic, for example, the division of the modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms. The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment. The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above-described embodiments, a person skilled in the art should understand that the technical solutions described in the above-described embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements are The essence of the corresponding technical solutions does not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A laser processing method, characterized in that: include: The first laser is focused on the interior of the workpiece to form one or more modification marks inside the workpiece; A second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace.

2. The laser processing method according to claim 1, characterized in that: The workpiece has a C surface; The first laser is focused on the interior of the workpiece to form one or more modification marks inside the workpiece, including: The first laser moves relative to the workpiece along a first path and focuses on the inside of the workpiece to form a modified mark inside the workpiece; The second laser irradiates the modified trace to form an absorption trace so as to generate cracks inside the workpiece, comprising: The second laser moves relative to the workpiece along a second path, and the second laser irradiates the modified trace to form an absorption trace and continues to irradiate different modified traces along the second path to form the absorption trace, so that cracks can be generated inside the workpiece along the C surface; The first laser and the second laser are different lasers; The first path intersects the second path.

3. The laser processing method according to claim 2, characterized in that: The workpiece is a crystalline material having a crystal orientation; The second laser moves relative to the workpiece along a second path, comprising: The second laser moves relative to the workpiece along a direction parallel to the crystal direction; Alternatively, the second laser moves relative to the workpiece along a direction forming a first specified angle with the crystal direction.

4. The laser processing method according to claim 3, characterized in that: The workpiece also has a first positioning surface, and the first positioning surface is perpendicular to the crystal direction; The first laser moves relative to the workpiece along a first path, comprising: The first laser moves relative to the workpiece along a direction forming a second specified angle with the first positioning surface.

5. The laser processing method according to claim 3, characterized in that: The workpiece also has a second positioning surface, and the second positioning surface is parallel to the crystal direction; The second laser moves relative to the workpiece along a direction forming a first specified angle with the crystal direction, comprising: The second laser moves relative to the workpiece along a direction forming a first specified angle with the second positioning surface.

6. The laser processing method according to claim 3, characterized in that: The crystal orientation is Crystal direction; the first specified angle is greater than 0° and less than or equal to 20°.

7. The laser processing method according to claim 2, characterized in that: The first path includes a straight path, a concentric circle path, or a spiral path; The second path includes a straight line path or a broken line path.

8. The laser processing method according to claim 2, characterized in that: The first path is perpendicular to the second path.

9. The laser processing method according to claim 1, characterized in that: The peak power density of the second laser is outside the peak power density range that can produce nonlinear absorption in the region outside the modified trace alone.

10. The laser processing method according to claim 1, characterized in that: Along the transverse direction of the workpiece, the transverse dimension of the absorption mark is greater than the transverse dimension of the corresponding modification mark, and the transverse direction is perpendicular to the thickness direction of the workpiece.

11. The laser processing method according to claim 1, characterized in that: The workpiece is a crystalline material having a crystal orientation; The second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The second laser moves relative to the workpiece along a direction forming a first specified angle with the crystal direction and irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece.

12. The laser processing method according to claim 11, characterized in that: The crystal material is an off-axis crystal material; the crystal orientation is Crystal direction; the first specified angle is greater than 0° and less than or equal to 20°.

13. The laser processing method according to claim 1, characterized in that: The first laser is focused on the inside of the workpiece to form one or more modification marks inside the workpiece, specifically: The first laser moves relative to the workpiece and focuses on the inside of the workpiece to form one or more modification marks inside the workpiece; The second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The second laser moves relative to the workpiece and irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece.

14. The laser processing method according to claim 13, characterized in that: Along the direction in which the second laser moves relative to the workpiece, two adjacent areas irradiated by the focus of the second laser have overlapping parts, so that cracks can be generated in the area between the two absorption marks.

15. The laser processing method according to claim 14, characterized in that: Along the direction in which the second laser moves relative to the workpiece, there is at least one region irradiated by the focus of the second laser between the two absorption marks.

16. The laser processing method according to claim 13, characterized in that: Along the direction in which the first laser moves relative to the workpiece, the gap distance between two adjacent modified marks is smaller than the spot size of the focus of the second laser.

17. The laser processing method according to claim 13, characterized in that: The first laser moves relative to the workpiece and focuses on the inside of the workpiece to form one or more modification marks inside the workpiece, specifically: The first laser moves relative to the workpiece along a first path and focuses on the inside of the workpiece to form one or more modification marks inside the workpiece; The second laser moves relative to the workpiece and the second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The second laser moves relative to the workpiece along the first path and irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece.

18. The laser processing method according to claim 13, characterized in that: The second laser moves relative to the workpiece and the second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The second laser moves relative to the workpiece along a specified direction and irradiates a portion of the modified trace to form an absorption trace. The second laser switches and moves relative to the workpiece in a direction parallel to the specified direction and irradiates another portion of the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece.

19. The laser processing method according to claim 1, characterized in that: The second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The second laser irradiates the modified trace multiple times in an intermittent manner to form an absorption trace, so that cracks can be generated inside the workpiece.

20. The laser processing method according to claim 19, characterized in that: The second laser irradiates the modified trace multiple times in an intermittent manner to form an absorption trace, so that cracks can be generated inside the workpiece, specifically: The plurality of pulse lasers of the second laser successively irradiate the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece; Alternatively, the second laser moves relative to the workpiece along the same path for multiple times and the second laser irradiates the modified trace to form an absorption trace, so that cracks can be generated inside the workpiece.

21. The laser processing method according to claim 1, characterized in that: The first laser is a pulse laser with a first pulse width, and the second laser is a pulse laser with a second pulse width, wherein the second pulse width is greater than the first pulse width.

22. The laser processing method according to any one of claims 1 to 21, characterized in that: The workpiece is a silicon carbide ingot with a C-face; the silicon carbide ingot is an eccentric silicon carbide ingot; the cracks are distributed along the C-face; the modified traces contain polycrystalline silicon carbide crystals; the area outside the modified traces is an area of ​​the workpiece that has not been irradiated by the first laser; the area outside the modified traces is basically single-crystalline silicon carbide crystals.

23. A laser processing device, characterized in that: include: A first processing module is used to focus a first laser on the inside of the workpiece to form one or more modification marks on the inside of the workpiece; The second processing module is used to: irradiate the modified trace with a second laser to form an absorption trace, so that cracks can be generated inside the workpiece; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace.

24. A device, characterized in that Manufactured by the laser processing method according to any one of claims 1 to 22.

25. The device according to claim 24, characterized in that The device has the modification trace and the absorption trace; Along the transverse direction of the workpiece, the transverse dimension of the absorption mark is greater than the transverse dimension of the corresponding modification mark, and the transverse direction is perpendicular to the thickness direction of the workpiece.

26. The device according to claim 24, characterized in that The device has intersecting machining traces.

27. A device, characterized in that It has traces of modification, absorption and cracks; The modified trace is formed by focusing the first laser on the inside of the workpiece; The crack is formed inside the workpiece by irradiating the modified trace with a second laser to form the absorption trace; The absorption rate of the second laser beam by the modification trace is greater than the absorption rate of the second laser beam by the area other than the modification trace.

28. A processing equipment, characterized in that: The method comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the laser processing method according to any one of claims 1 to 22 when executing the computer program.

29. A crystal material stripping device, characterized in that: include: an irradiation unit, configured to emit a first laser to focus on the interior of a crystal material to form one or more modified traces inside the crystal material, and to emit a second laser to irradiate the modified traces to form absorption traces, so that cracks can be generated inside the crystal material; The absorption rate of the modified trace to the second laser is greater than that of the area outside the modified trace to the second laser. Absorption rate; The stripping unit is used to strip a wafer from the crystal material using the crack as a starting point.

30. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the laser processing method according to any one of claims 1 to 22 is implemented.

Images