Laser processing device

Abstract

The utility model discloses a laser processing device. The laser processing device comprises a laser used for emitting a laser beam with preset laser parameters; the beam splitting element is used for splitting the laser beam into a plurality of sub-beams arranged along a preset direction; the spherical aberration compensation element is used for performing spherical aberration compensation on the plurality of sub-beams and outputting a plurality of spherical aberration compensation beams; and the scanning mechanism is used for focusing the plurality of spherical aberration compensation light beams and cutting the silicon carbide crystal ingot according to a preset cutting path and a preset cutting speed by utilizing the plurality of focused spherical aberration compensation light beams. Spherical aberration compensation is carried out on the sub-beams, the spot size of the focused sub-beams in the silicon carbide crystal ingot in the optical axis direction can be remarkably reduced, the length of a growth area of microcracks is reduced, and then a high-quality silicon carbide wafer is obtained. In addition, the coverage area of the plurality of sub-beams on the surface of the silicon carbide crystal ingot is larger, so that the cutting efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of laser technology, specifically to a laser processing device. Background Technology

[0002] In today's rapidly developing global semiconductor industry, silicon carbide (SiC), with its superior physical and chemical properties, has become a key material for manufacturing high-performance electronic devices. However, the production cost of silicon carbide is very high. To reduce costs, a large silicon carbide ingot needs to be cut into as many thin silicon carbide wafers as possible. But silicon carbide is extremely hard and also brittle, making it very difficult to cut.

[0003] Currently, laser cutting technology is commonly used to cut silicon carbide ingots (also known as peeling or slicing). While laser cutting technology offers many significant advantages, achieving a dual improvement in cutting efficiency and quality remains a challenge. On one hand, efficiency and quality are often mutually restrictive, requiring a proper balance. On the other hand, the inherent hardness and fragility of silicon carbide ingots further complicates this challenge by ensuring both high efficiency and high quality during the cutting process. Utility Model Content

[0004] In view of this, the present invention provides a laser processing device that can simultaneously take into account both the cutting efficiency and the cutting quality of silicon carbide ingots.

[0005] In a first aspect, embodiments of the present invention provide a laser processing apparatus, comprising: a laser for emitting a laser beam having preset laser parameters; a beam splitting element for splitting the laser beam into multiple sub-beams arranged along a preset direction; a spherical aberration compensation element for compensating for spherical aberration in the multiple sub-beams and outputting multiple spherical aberration compensated beams; and a scanning mechanism for focusing the multiple spherical aberration compensated beams and using the multiple focused spherical aberration compensated beams to cut a silicon carbide ingot with a preset cutting path and a preset cutting speed.

[0006] In some embodiments, the laser processing apparatus further includes: a controller for determining spherical aberration caused by the mismatch between the refractive index of air and the refractive index of a silicon carbide ingot, and determining a spherical aberration compensation phase map required to correct the spherical aberration, wherein the spherical aberration compensation element includes a spatial light modulator loaded with a plurality of spherical aberration compensation phase maps, one of which is used to compensate for spherical aberration of a sub-beam.

[0007] In some embodiments, the laser processing apparatus further includes: a controller for controlling the laser to emit a laser beam with preset laser parameters, controlling a spherical aberration compensation element to perform spherical aberration compensation on multiple sub-beams, and controlling a scanning mechanism to enable multiple focused spherical aberration compensation beams to cut silicon carbide ingots at preset cutting paths and preset cutting speeds.

[0008] In some embodiments, the laser processing apparatus further includes a controller, wherein the scanning mechanism includes a focusing optical element and a triaxial displacement stage for carrying a silicon carbide ingot, the focusing optical element is used to focus multiple aberration-compensated beams to obtain multiple focused aberration-compensated beams, and the controller controls the movement of the triaxial displacement stage so that the multiple focused aberration-compensated beams cut the silicon carbide ingot with a preset cutting path and a preset cutting speed.

[0009] In some embodiments, the laser processing apparatus further includes a controller, wherein the scanning mechanism includes a focusing optical element and a galvanometer group, the focusing optical element is used to focus multiple spherical aberration compensation beams to obtain multiple focused spherical aberration compensation beams, and the controller controls the deflection angle of the galvanometer group so that the multiple focused spherical aberration compensation beams cut the silicon carbide ingot with a preset cutting path and a preset cutting speed.

[0010] In some embodiments, the beam-splitting element includes a Damman grating.

[0011] In some embodiments, the angle between the preset direction and the first direction perpendicular to the preset cutting path is greater than or equal to 0° and less than or equal to 45°.

[0012] In some embodiments, the preset cutting speed is 15 mm / s to 50 mm / s, and the spacing between adjacent laser processing lines in the preset cutting path is 30 μm to 50 μm.

[0013] In some embodiments, the laser includes a femtosecond laser, and the preset laser parameters include: a pulse width of 190 fs to 350 fs, a repetition frequency of 50 kHz to 500 kHz, and an average power of 1 W to 2 W.

[0014] In some embodiments, the preset laser parameters include: a repetition frequency of 100 kHz, an average power of 1.5 W, and a pulse width of 300 fs.

[0015] In the laser processing scheme of this invention, spherical aberration compensation of multiple sub-beams significantly reduces the spot size of each focused sub-beam along the optical axis inside the silicon carbide ingot. This reduces the length of the growth region for microcracks generated along the optical axis during processing, thereby achieving finer control during laser cutting of silicon carbide ingots and obtaining high-quality silicon carbide wafers. Furthermore, using multiple sub-beams to cut the silicon carbide ingot results in a larger surface coverage area compared to a single-focus Gaussian beam, improving cutting efficiency, also known as slicing efficiency. Therefore, this approach brings a dual improvement in efficiency and quality to the processing of silicon carbide ingots. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a laser processing device provided in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of a laser processing device provided in another embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of a Dammann grating under a birefringence microscope according to an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the distribution of multiple sub-beams provided in one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of a spherical aberration compensation phase diagram provided in an embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the spot morphology of a focused beam with spherical aberration compensation and a focused beam without spherical aberration compensation in the XZ plane inside a silicon carbide ingot, according to an embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the cutting path of multiple aberration-compensated beams on the XY plane of a silicon carbide ingot provided in one embodiment of the present invention.

[0023] Figure 8 This is a microscope image of a silicon carbide ingot after cutting, provided in one embodiment of the present invention.

[0024] Figure 9 This is a schematic flowchart of a method for cutting silicon carbide ingots according to an embodiment of the present invention.

[0025] Figure 10 This is a schematic diagram of the structure of a silicon carbide ingot cutting system provided in one embodiment of the present invention.

[0026] Figure 11 This is a block diagram of a laser processing system provided in one embodiment of the present invention. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples of devices and methods consistent with some aspects of this invention as detailed in the appended claims.

[0028] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless otherwise clearly indicated below. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items. It should also be understood that the word “if” as used herein, depending on the context, can be interpreted as “when,” “in response to a determination,” or “when…”.

[0029] In current laser cutting technology, multi-focus beams, flat-top beams, or Bessel beams are commonly used to improve the cutting efficiency of silicon carbide ingots. While these beams can improve cutting efficiency to some extent, they do not always guarantee cutting quality. This is because some technical challenges in laser cutting of silicon carbide ingots have not yet been fully overcome. For example, the excessively large range of laser-induced microcracks or the difficulty in controlling the thickness of the chemically decomposed layer of silicon carbide under laser irradiation can lead to a certain degree of roughness on the surface of the silicon carbide wafer, thereby reducing the quality of the silicon carbide wafer. Therefore, although these beam technologies have played a role in improving cutting efficiency, further technological breakthroughs and optimizations are needed to ensure cutting quality.

[0030] However, it should be noted that this invention is not limited to cutting silicon carbide ingots, but is also applicable to cutting other brittle and hard inorganic non-metallic materials or semiconductor materials, such as glass and silicon wafers. These materials encounter similar problems to those encountered during silicon carbide ingot cutting, such as the inability to simultaneously guarantee cutting quality and efficiency, excessively large laser-induced microcrack formation areas, or difficulty in controlling the thickness of the chemically decomposed silicon carbide layer under laser irradiation. Therefore, the solution proposed in this invention has broad applicability and can provide technical support for the precision cutting of various hard and brittle materials.

[0031] To make it easier to understand, the generation of microcracks and the formation of the chemical decomposition layer will be briefly introduced below.

[0032] When a laser is focused inside silicon carbide, the accumulation of heat creates a gradient heat-affected zone within the silicon carbide. Within this heat-affected zone, the silicon carbide experiences varying thermal stresses, leading to the formation of microcracks due to uneven stress distribution.

[0033] A chemical decomposition layer typically refers to a layer formed when silicon carbide undergoes a chemical change under laser irradiation, resulting in the material decomposing into new phases of its constituent elements or compounds. For example, laser-induced phase separation can cause silicon carbide to decompose into amorphous silicon and amorphous carbon, and even further transform into multilayered graphene. The formation of such a decomposition layer usually involves the interaction between the laser and the material, such as a high-power laser beam focused on the material surface, leading to rapid heating and phase transitions in localized areas.

[0034] The formation of a chemically decomposed layer may also be accompanied by the generation of microcracks, which can form inside the material and affect its integrity and mechanical properties.

[0035] Research has shown that both the laser beam shape and the heat diffusion of the laser can cause microcracks to propagate outwards. For example, inhomogeneity in the laser beam shape can cause significant internal damage to the silicon carbide wafer during the cutting process, resulting in surface roughness and affecting the quality of the silicon carbide wafer. Therefore, to prevent microcracks from propagating outwards, it is essential to concentrate microcrack formation along the laser scanning path (i.e., the cutting path described below). However, given the numerous beam shapes and laser parameters to choose from, selecting the appropriate beam shape and laser parameters for cutting silicon carbide ingots becomes a crucial factor determining the cutting effect.

[0036] Further experimental exploration and theoretical research revealed that reducing the spot size of the focused beam along the optical axis (also known as the depth of focus) can effectively control the growth of microcracks in silicon carbide ingots and precisely regulate the thickness of the chemically decomposed layer under laser irradiation. The key to this discovery is that shortening the beam spot size reduces the length of the growth region of microcracks generated along the optical axis during processing, thereby achieving finer control during laser cutting of silicon carbide ingots and ultimately obtaining high-quality silicon carbide wafers.

[0037] Therefore, in the laser processing scheme of this invention, spherical aberration compensation for multiple sub-beams can significantly reduce the spot size of each focused sub-beam along the optical axis inside the silicon carbide ingot, thereby reducing the length of the growth region of microcracks generated along the optical axis during processing. This allows for finer control during laser cutting of silicon carbide ingots, resulting in high-quality silicon carbide wafers. Furthermore, using multiple sub-beams to cut the silicon carbide ingot improves cutting efficiency, also known as slicing efficiency, because the coverage area of ​​multiple sub-beams on the surface of the silicon carbide ingot is larger than that of a single-focus Gaussian beam. Thus, the processing of silicon carbide ingots brings a dual improvement in efficiency and quality.

[0038] The following is combined with Figure 1 and 2 The laser processing apparatus provided in the embodiments of this utility model will be described in more detail.

[0039] like Figure 1 and 2 As shown, the laser processing apparatus includes a laser 110, a beam splitter 160, a spherical aberration compensation element 170, and a scanning mechanism arranged sequentially along the optical path. The laser 110 is used to emit a laser beam with preset laser parameters; the beam splitter 160 is used to split the laser beam into multiple sub-beams arranged along a preset direction; the spherical aberration compensation element 170 is used to compensate for spherical aberration in the multiple sub-beams and output multiple spherical aberration compensated beams; the scanning mechanism is used to focus the multiple spherical aberration compensated beams and use the multiple focused spherical aberration compensated beams to cut silicon carbide ingots at a preset cutting path and a preset cutting speed.

[0040] by Figure 1 and 2 For example, the specific components of the scanning mechanism are shown.

[0041] In one example, such as Figure 1 As shown, the scanning mechanism includes a focusing optical element 181 and a triaxial displacement stage 183 for supporting the silicon carbide ingot 190.

[0042] The focusing optical element 181 includes a sleeve lens 1811 and an objective lens 1812. The combination of the sleeve lens 1811 and the objective lens 1812 is used because the optical field area of ​​the multiple spherical aberration compensation beams is relatively large, but the entrance pupil of the objective lens 1812 is relatively small. Therefore, the sleeve lens 1811 for pre-focusing is set in front of the objective lens 1812, while the objective lens 1812 is used to focus the multiple spherical aberration compensation beams into the interior of the silicon carbide ingot 190.

[0043] However, it should be noted that the specific composition of the condensing optical element 181 is not limited to the components listed above. Those skilled in the art can select and adjust the composition of the condensing optical element 181 according to actual application requirements. For example, the condensing optical element 181 may only include the objective lens 1812, and the condensing optical element 181 may only need to meet the focusing function.

[0044] In addition to the above, the scanning mechanism may also include other components, such as a dichroic mirror 182 located between the sleeve lens 1811 and the objective lens 1812. A three-axis displacement stage 183 is located after the objective lens 1812. However, it should be noted that the specific composition of the scanning mechanism is not limited to the components listed above, and those skilled in the art can select and adjust the composition of the scanning mechanism according to actual application requirements.

[0045] Based on this, the laser processing apparatus also includes: a controller 109 and a charge-coupled device (CCD) 184 located after the dichroic mirror 182. The dichroic mirror 182 is also used to allow the imaging light source of the CCD 184 to enter the focusing optical element 181; the CCD 184 is used to perform imaging detection of the laser processing process through the dichroic mirror 182; the controller 109 is used to control parameters such as the repetition frequency, pulse width, and pulse energy of the laser beam emitted by the laser 110, and is also used to control the movement of the three-axis displacement stage 183 and the imaging of the CCD 184.

[0046] The controller 109 controls the movement of the three-axis displacement stage 183 so that multiple focused spherical aberration compensated beams obtained after being focused by the focusing optical element 181 move on the silicon carbide ingot 190 with a preset cutting path and a preset cutting speed. The preset cutting speed is 15 mm / s to 50 mm / s, preferably 25 mm / s.

[0047] The controller 109 controls the three-axis displacement stage 183 to achieve precise position adjustment at the sub-micron level, thereby improving cutting accuracy.

[0048] In another example, such as Figure 2 As shown, the scanning mechanism includes a focusing optical element 181 and a galvanometer assembly (which includes galvanometer 1851 and galvanometer 1852).

[0049] In addition, scanning agencies include not only Figure 2 The elements shown in the document may also include other elements not listed. Figure 2 The components shown in the diagram, these components are Figure 1 Detailed descriptions have already been provided. For example, the scanning mechanism also includes a sleeve lens 1811 and an objective lens 1812 located after the galvanometer 1852 (which also constitute a...). Figure 2The scanning mechanism includes a focusing optical element 181 and a dichroic mirror 182 located between the sleeve lens 1811 and the objective lens 1812. A three-axis displacement stage 183 is located behind the objective lens 1812. However, it should be noted that the specific composition of the scanning mechanism is not limited to the components listed above. Those skilled in the art can select and adjust the composition of the scanning mechanism according to actual application requirements.

[0050] Based on this, the laser processing apparatus also includes: a controller 109 and a charge-coupled device (CCD) 184 located after the dichroic mirror 182. The dichroic mirror 182 is also used to allow the imaging light source of the CCD 184 to enter the focusing optical element 181; the CCD 184 is used to image and detect the laser processing process through the dichroic mirror 182; the controller 109 is used to control parameters such as the repetition frequency, pulse width, and pulse energy of the laser beam emitted by the laser 110, and is also used to control the deflection angle of the galvanometer group and control the imaging of the CCD 184.

[0051] The controller 109 controls the deflection angle of the galvanometer group so that multiple focused spherical aberration-compensated beams obtained after being focused by the condensing optical element 181 move on the silicon carbide ingot 190 with a preset cutting path and a preset cutting speed. The preset cutting speed is 15 mm / s to 50 mm / s, preferably 25 mm / s.

[0052] The controller 109 controls the galvanometer assembly to achieve high-speed and high-precision beam scanning, and then works with the objective lens to focus the light field, thereby improving cutting efficiency and cutting accuracy.

[0053] It should be understood that Figure 2 The dashed lines in the diagram depict the complete area that multiple spherical aberration compensation beams can cover under the deflection of the galvanometer array. Figure 2 The dashed line indicates the maximum range achievable by multiple spherical aberration compensation beams under the control of the galvanometer group. Figure 2 The figure represents the complete spatial range that multiple spherical aberration-compensated beams can reach under the dynamic deflection of the galvanometer array.

[0054] It should be noted that, Figure 1 and 2 The thick black lines are merely schematic representations of the components that the controller 109 can control. Those skilled in the art can select and adjust the components controlled by the controller 109 according to actual application requirements. For example, in... Figure 2In addition, the controller 109 can also control the movement of the three-axis displacement stage 183. That is, the galvanometer group and the three-axis displacement stage 183 work together to make multiple focused spherical aberration compensation beams move on the silicon carbide ingot 190 with preset cutting paths and preset cutting speeds.

[0055] It should be understood that when we say A is before or after B in this article, we mean that A is before or after B along the direction of light propagation.

[0056] exist Figure 1 and Figure 2 Based on this, the laser processing device also includes: a reflector 153 located between the beam splitting element 160 and the spherical aberration compensation element 170 and arranged sequentially in the optical path, a lens group (which includes lens 154 and lens 156, which form a 4f system) and an aperture 155.

[0057] The reflector 153 is used to reflect the multiple sub-beams obtained after beam splitting by the beam splitting element 160 to the lens group; the lens group is used to expand or shrink the multiple sub-beams; the aperture 155 is used to perform spatial filtering on the multiple sub-beams to improve the beam splitting quality.

[0058] The process of splitting a laser beam is explained in detail below.

[0059] In one example, when the beam splitter 160 is a Damman grating, such as Figure 1 and 2 As shown, the laser processing apparatus also includes: an angle stabilizing component 120, a power adjustment component 130, a beam expander 140, a reflector 151, and a half-wave plate 152, which are located between the laser 110 and the beam splitting element 160 and are arranged sequentially in the optical path. Angle stabilization component 120 is used to maintain the directional stability of the laser beam during the collimation process, that is, to control the angle stability of the laser (also known as the stability of laser directivity) to ensure the collimation stability of the output optical path. The angle stabilization component 120 has an internal feedback device that can control the laser direction in real time. Power adjustment component 130 is used to maintain the stability of laser power, for example, to adjust the laser power to a range of 0.3% to 99% under a specific polarization. Beam expander 140 is used to expand the spot of the laser beam emitted by laser 110 to a preset multiple, for example, 2 to 6 times. Reflector 151 is used to reflect the laser beam expanded by beam expander 140 to half-wave plate 160. Half-wave plate 152 is used to change the polarization direction of the laser beam so that the laser beam is incident on beam splitter 160 with a suitable polarization direction.

[0060] The angle stabilization component 120 and the power adjustment component 130 enable the laser parameter output to be more stable, thereby ensuring the stable generation of microcracks inside the silicon carbide ingot.

[0061] The angle stabilization component 120 may include a deflecting mirror and a closed-loop controller. The closed-loop controller is an electronic system used to continuously monitor the deviation between the laser beam and the target position and control the deflecting mirror to adjust it to maintain the stability of the laser beam. However, this embodiment of the invention does not limit the specific composition of the angle stabilization component, and those skilled in the art can make different selections according to actual application requirements.

[0062] The power adjustment component 130 may include a laser power controller or an optical power regulator / limiter, etc., and those skilled in the art can make different selections according to actual application requirements.

[0063] The purpose of placing a half-wave plate 152 before the beam splitter 160 is to utilize the characteristic that the phase difference between two adjacent strip regions of the Dammann grating is π, thereby achieving a more uniform beam splitting effect. This beam splitting uniformity reaches its optimal state when the incident laser beam is linearly polarized, and the diffraction efficiency can approach the theoretical value. Therefore, the polarization direction of the incident laser beam is adjusted by using the half-wave plate 152, thereby optimizing the beam splitting performance.

[0064] In this invention, the transmittance of the Damman grating is >97%, the beam splitting mode is 1×7, the maximum beam splitting angle is 2°, and the beam splitting uniformity is greater than 85%. However, it should be noted that the specific parameter values ​​of the Damman grating used in this invention are not limited to the parameter values ​​listed above. Different parameter values ​​can be set for different application requirements, for example, the beam splitting mode is 1×5.

[0065] It should be understood that if the beam splitter 160 does not have specific requirements for the polarization state of the light, then it can be omitted in this case. Figure 1 and Figure 2 The half-wave plate 152 shown is shown.

[0066] The Damman grating will be explained in detail below. Figure 3 As shown, it illustrates the structure of the Dammann grating under a birefringent microscope.

[0067] A Dammann grating is a diffractive optical element that achieves uniform beam splitting. Its structure consists of a series of position-coded binary phase (0-π) structures. This design enables the Dammann grating to achieve uniform beam splitting; that is, by controlling the position of the binary phase transition point within one cycle, the intensity of multiple orders of laser far-field diffraction spots can be easily equalized. The Dammann grating possesses unique advantages such as a planar structure, high diffraction efficiency, and high beam splitting ratio. In the field of femtosecond laser processing, these advantages allow the Dammann grating to provide multifocal laser beam shaping, improving laser processing efficiency and thus significantly enhancing the efficiency and effectiveness of laser processing.

[0068] In this invention, the Damman grating has a typical sandwich structure. In the liquid crystal polymer (LCP) layer, the fast axis orientation of the liquid crystal molecules exhibits a binary periodic variation of 0 to 90° along the x-axis. This design provides a λ / 2 retardation across the entire device plane, making the Damman grating a single-wavelength device. Compared with traditional gratings and cascaded grating beam splitters, a significant advantage of the Damman grating is that it can achieve odd-numbered beam splitting and a large number of beam points using only a monolithic structure, while ensuring equal spacing and intensity between each beam spot.

[0069] In a Damman grating, the beam splitting angle θ is defined as the maximum total diffraction angle of the outgoing beam splitting spot, while the separation angle δ is the angle between two adjacent beam splitting spots. Calculated according to the grating diffraction formula: d = mλ, where d is the period of the Damman grating, m is the order of the diffraction spot, and λ is the operating wavelength. For a standard one-dimensional Damman grating, the beam splitting angle θ refers to the full diffraction angle corresponding to the outermost diffraction order spot, i.e., Figure 4 In the equation θ, there is an approximate relationship with the separation angle δ: θ≈6δ. This relationship indicates that the beam splitting angle θ is approximately six times the separation angle δ. This approximation helps in predicting and calculating the distribution of the outgoing beam spot when designing and applying Damman gratings.

[0070] like Figure 4 As shown, when the laser beam 11 passes through the Damman grating 160 at a beam-splitting angle θ, it can generate n sub-beams, where n is greater than 1. Each sub-beam has its own focal point. Therefore, when the n sub-beams are combined together, they together form a Gaussian light field with multiple focal points. In other words, by using the Damman grating, a single Gaussian beam is split into a multi-focal Gaussian light field, achieving a multi-focal distribution of the beam.

[0071] The advantages of the Dammann grating mentioned above result in good uniformity and high wavefront consistency among the multiple sub-beams. In particular, each sub-beam exhibits Gaussian beam characteristics, which greatly facilitates the subsequent calculation process for spherical aberration correction. Furthermore, due to the good uniformity of the multiple sub-beams, microcracks are generated uniformly during the cutting of silicon carbide ingots, and the generation range of microcracks is more controllable, thereby reducing losses.

[0072] The process of spherical aberration compensation for sub-beams will be explained in detail below.

[0073] In one example, the spherical aberration compensation element 170 can be a spatial light modulator (SLM). A spatial light modulator is a programmable beam shaping device. When multiple sub-beams output from the beam splitter 160 pass through the target surface of the spatial light modulator, the liquid crystal layer changes the deflection direction of the liquid crystal molecules under the control of the electric field, thereby modulating the phase of the multiple sub-beams. Subsequently, the controller 109 precisely controls the electric field, causing the multiple sub-beams to be loaded with preset phase information, ultimately achieving the output of multiple spherical aberration compensated beams.

[0074] Spatial light modulators precisely control the light field by loading preset phase information, thereby changing the focusing pattern of multiple sub-beams inside silicon carbide.

[0075] In this invention, spherical aberration compensation is performed on multiple sub-beams using a spatial light modulator, which is loaded with... Figure 5 The diagram shows multiple spherical aberration compensation phase maps (each containing preset phase information). One spherical aberration compensation phase map is used to compensate for spherical aberration in a sub-beam to optimize beam focusing. The spherical aberration compensation phase map describes the laser parameters that need to be adjusted during spherical aberration correction in terms of phase.

[0076] although Figure 5 Only seven spherical aberration compensation phase diagrams are shown, but those skilled in the art should understand that the number of spherical aberration compensation phase diagrams is not limited to seven as the number of sub-beams increases. In fact, each sub-beam corresponds to a dedicated spherical aberration compensation phase diagram to achieve precise control over each sub-beam.

[0077] By combining the use of Dammann gratings and spatial light modulators, the cutting efficiency and quality of silicon carbide ingots can be significantly improved. This combined application method leverages the advantages of Dammann gratings in terms of uniformity and wavefront consistency, along with the flexible wavefront control capabilities of spatial light modulators, thereby achieving precise and efficient cutting of silicon carbide ingots.

[0078] In addition, other optical elements are provided after the spatial light modulator, including but not limited to the sleeve lens 1811, the dichroic mirror 182, the objective lens 1812, and the galvanometer group. These optical elements also perform Fourier transform on the spherical aberration compensation beam to dynamically control the light field, thereby improving the morphology of the laser focused inside the silicon carbide ingot.

[0079] As mentioned above, spatial light modulators can load multiple spherical aberration-compensated phase maps. In fact, the spherical aberration-compensated phase map is the result of the spherical aberration correction process. Before loading these phase maps, the required spherical aberration compensation for each sub-beam (i.e., the spherical aberration caused by the mismatch between the refractive index of air and the refractive index of silicon carbide ingot) is determined to ensure accurate spherical aberration compensation for each sub-beam. The specific process of spherical aberration correction and how these spherical aberration-compensated phase maps are obtained will be described in detail below.

[0080] It should be understood that spherical aberration compensation and spherical aberration correction are two distinct steps. Spherical aberration correction is performed before spherical aberration compensation, and its purpose is to determine the required amount of spherical aberration compensation for each sub-beam and to determine the spherical aberration compensation phase diagram needed to correct the spherical aberration compensation amount. Spherical aberration compensation, on the other hand, is performed based on spherical aberration correction, applying the corresponding amount of spherical aberration compensation to each sub-beam; that is, using the spherical aberration compensation phase diagram determined during the spherical aberration correction process, spherical aberration is compensated for in each sub-beam.

[0081] During laser cutting, the laser beam (i.e., each sub-beam mentioned above) passes through two different media (i.e., air and silicon carbide ingot). Due to the difference in refractive index between air and silicon carbide ingot, the shape of the laser spot changes when the laser beam is focused inside the silicon carbide ingot due to the refractive index mismatch.

[0082] Research has shown that changes in the shape of the light spot due to refractive index mismatch can cause microcracks to spread outwards, resulting in a certain degree of roughness on the surface of the silicon carbide wafer, which in turn affects the quality of the silicon carbide wafer.

[0083] Therefore, in order to mitigate the impact of refractive index mismatch on the beam morphology and thus prevent microcracks from spreading outwards, spherical aberration correction technology can be used to optimize beam focusing, thereby improving cutting quality.

[0084] Next, we will introduce a spherical aberration correction method with an example. This method is based on Zernike polynomial phase difference and aims to correct wavefront distortion caused by refractive index mismatch, thereby correcting the spot shape. In practice, a preset phase information is loaded through a spatial light modulator, causing the spot to undergo the expected shape change before entering the silicon carbide ingot, thus achieving spherical aberration compensation.

[0085] When the laser beam passes through refractive indices respectively air and After the silicon carbide ingot is formed, the laser beam passing through the objective lens will generate a deviated wavefront. This wavefront deviation function is expressed as: ,in, This indicates the depth to which the light spot is focused within the silicon carbide ingot, while Representing the normalized radius coordinates, defined as follows: ,in, and These represent the incident angle and exit angle of the laser beam at the interface between the air and the silicon carbide ingot, respectively. and These are the maximum incident angle and the maximum exit angle, respectively. The numerical aperture of the objective lens is... Defined as When cutting silicon carbide ingots, if the laser beam needs to be focused at a specific depth inside the ingot, then... This is equal to the optical path difference of the laser beam in air and in the silicon carbide ingot, that is:

[0086] (Formula 1)

[0087] in, , .

[0088] According to Fresnel's law of refraction, we can conclude that: .

[0089] Will , as well as Substituting these relationships into Formula 1, we can obtain:

[0090] (Formula 2)

[0091] Then, Substituting into formula 2, we get: .

[0092] The beam distortion caused by focusing a laser beam inside a silicon carbide ingot leads to wavefront deviation. This deviation, combined with the defocus pupil function, can be expressed as:

[0093]

[0094] in, For the pupil function normalized to the radius, in In this case, In other cases, .definition At this point, the diffusion function away from the focal point is:

[0095]

[0096]

[0097] in, , Indicates the wavelength of the laser; , The normalized transverse and longitudinal coordinates of the laser beam are respectively defined as:

[0098]

[0099] in, , These represent the lateral and longitudinal displacements of the light spot at the focal point, respectively, i.e., the defocus distance caused by refractive index mismatch. Based on these displacement parameters, the light intensity distribution in the focal region inside the silicon carbide ingot can be defined as: .

[0100] To correct the beam pattern, the spatial light modulator is loaded with a spherical aberration-compensated phase map. This design preloads a compensating spherical aberration (i.e., spherical aberration arising from the mismatch between the refractive index of air and the refractive index of silicon carbide) onto the light field before it enters the silicon carbide ingot. To determine this compensating spherical aberration, a pre-corrected spherical aberration (i.e., spherical aberration calculated based on the refractive index of air and the refractive index of silicon carbide ingot) is first determined. This pre-corrected spherical aberration can be expanded using a zero-order Zernike polynomial, specifically expressed as:

[0101]

[0102] in, ( (even number) , .

[0103] In the zeroth-order Zernike polynomial, when hour, These correspond to the following expressions respectively:

[0104] hour, =1 indicates a constant that has no effect on the focusing pattern of the laser inside the silicon carbide ingot;

[0105] When = 2, = This indicates defocusing, which causes the focused spot inside the silicon carbide ingot to shift axially, but has no effect on the size of the spot.

[0106] =4, = This reflects the influence of aberrations on the laser morphology inside silicon carbide ingots, leading to changes in the energy density of the laser spot;

[0107] =6 o'clock, = , representing second-order spherical aberration, is caused by refractive index mismatch and has a significant impact on the focal position and spot size of the laser beam.

[0108] To correct the effect of spherical aberration caused by refractive index mismatch on the beam pattern, the wavefront deviation function is modified. The core objective of this modification is to optimize the pupil function, making its value as close to 1 as possible, thereby ensuring optimal beam quality. To achieve this goal, the phase information loaded into the spatial light modulator is an inverse Zernike polynomial:

[0109]

[0110] in, This represents the level of ball difference compensation. When N When =0, only defocus correction was performed, meaning adjustments were made only for changes in the laser focusing position, without correcting for spherical aberration; when N When ≥1, spherical aberration caused by refractive index mismatch is corrected, which includes not only defocus correction but also correction of the laser spot morphology; as N Increasing the value allows for the correction of higher-order spherical aberrations, thereby achieving more refined and comprehensive correction of the laser focusing spot morphology.

[0111] To accurately compensate for spherical aberration caused by refractive index mismatch and correct the laser spot shape, this invention employs a compensation method based on inverse Zernik polynomials. Subsequently, the spherical aberration compensation series in the Zernik polynomials is iteratively optimized using the GCS algorithm (Gerchberg-Saxton (GS) algorithm). The optimized solution is used in polar coordinates to generate the corresponding inverse Zernik polynomial phase distribution, which is then loaded onto the spatial light modulator to achieve spherical aberration compensation for the laser focal spot.

[0112] It should be understood that the spherical aberration calculated based on the refractive index of air and the refractive index of silicon carbide ingot is expanded using a zero-order Zernike polynomial, while the spherical aberration arising from the mismatch between the refractive index of air and the refractive index of silicon carbide ingot is expanded using a reverse Zernike polynomial.

[0113] Through the aforementioned precise spherical aberration correction process, each sub-beam generates a corresponding spherical aberration-compensated phase diagram, such as... Figure 5 As shown, these spherical aberration compensation phase maps are loaded onto the spatial light modulator to achieve accurate compensation of spherical aberration for each sub-beam.

[0114] It should be noted that the specific components of the aforementioned laser processing device are not limited to... Figure 1 and 2The components illustrated above can be selected and adjusted by those skilled in the art according to actual application requirements. For example, more or fewer mirrors can be added. Furthermore, the order of components in a laser processing apparatus is not fixed; those skilled in the art can adjust the arrangement according to actual application requirements. Figure 1 and 2 Adjust the order of the components shown in the diagram.

[0115] The following is combined with Figure 6 and 7 This study compares aberration-compensated beams with uncompensated beams to better illustrate the significant advantages of using aberration-compensated beams in the silicon carbide ingot cutting process. Specifically, aberration-compensated beams can significantly improve cutting quality and increase cutting efficiency.

[0116] like Figure 6 As shown, it illustrates the optical field distribution of a focused beam on the XZ plane inside a silicon carbide ingot. It can be seen that, along the Z-axis (optical axis), the focused aberration-compensated beam (displayed in...) Figure 6 (on the right) compared to the focused beam without spherical aberration compensation (shown on) Figure 6 The left side of the beam has a smaller spot size. Compared to the focused beam without spherical aberration compensation, the spot size of the focused beam with spherical aberration compensation is reduced by 70% to 80% along the Z-axis.

[0117] Because the aberration-compensated beam after focusing has a smaller spot size than the uncompensated focused beam along the optical axis, this means that the aberration-compensated beam has a shallower effect depth inside the silicon carbide ingot 190. That is, the thickness of the loss layer where the microcracks are located is thinner. This not only reduces the length of the growth region of the microcracks generated along the optical axis during processing, thus controlling the growth region of the microcracks more precisely, but also effectively controls the thickness of the chemical decomposition layer under laser action. It can also improve the utilization rate of the silicon carbide ingot (i.e., reduce processing loss), because the thinner the loss layer where the microcracks are located, the more silicon carbide wafers can be cut from a whole silicon carbide ingot.

[0118] like Figure 7 As shown, the preset direction D and the first direction perpendicular to the preset cutting path (as indicated by the horizontal arrow line) (i.e., Figure 7 The angle between the beams and the Y-axis direction in the image is 0°. Multiple focused aberration-compensated beams 11-1…11-7 are positioned along the cutting plane of the silicon carbide ingot (i.e., ...). Figure 7The beam is spread out in a preset direction D parallel to the XY plane, and has a large coverage area. Compared with a single-focus beam without spherical aberration compensation, the spot size in the Y-axis direction of multiple focused spherical aberration compensated beams 11-1…11-7 increases by 280% to 320% after being combined.

[0119] Figure 7 Only one possible implementation is shown, in which the preset direction D is perpendicular to the preset cutting path and the angle between it and the Y-axis direction is 0°. In this implementation, compared to a single-focus Gaussian beam without spherical aberration compensation, the spot size of multiple focused spherical aberration compensated beams 11-1…11-7, after being combined, is significantly expanded in the Y-axis direction. Therefore, the interval between adjacent laser processing lines is correspondingly increased, that is, the laser processing line length becomes longer. This means that the number of laser actions on the silicon carbide ingot 190 (i.e., the number of scans) is reduced. This not only reduces the influence of thermal stress and thermal shock waves during multi-pulse deposition, thereby more accurately controlling the growth area of ​​microcracks, but also effectively controls the thickness of the chemical decomposition layer under laser action, and improves cutting efficiency.

[0120] However, it should be noted that... Figure 7 This illustration is merely schematic of one possible implementation where the preset direction D is perpendicular to the preset cutting path (i.e., the angle between the preset direction D and the first direction is 0°). In practice, the preset direction D may also intersect the preset cutting path, but it does not have to be perpendicular; that is, the angle between the preset direction D and the first direction is greater than 0° and less than or equal to 45°. Figure 7 This example uses the horizontal direction as the X-axis and the vertical direction as the Y-axis, but it can also be the horizontal direction as the Y-axis and the vertical direction as the X-axis.

[0121] Therefore, in the laser processing scheme of this invention, spherical aberration compensation is applied to multiple sub-beams arranged along a preset direction. This significantly reduces the spot size of each focused sub-beam along the optical axis inside the silicon carbide ingot, decreasing the length of the growth region for microcracks generated along the optical axis during processing. This allows for finer control during laser cutting of silicon carbide ingots, resulting in high-quality silicon carbide wafers. Furthermore, using multiple sub-beams to cut the silicon carbide ingot provides a larger coverage area due to the multiple sub-beams spreading along a preset direction parallel to the cutting plane of the silicon carbide ingot, thus improving cutting efficiency. Therefore, this method brings a dual improvement in efficiency and quality to the processing of silicon carbide ingots.

[0122] In other words, the laser processing solution of this invention can significantly increase the line spacing of laser scanning on silicon carbide ingots, thereby reducing the number of laser scans. This improvement helps reduce the cumulative thermal effect of the laser on the silicon carbide ingot, thus reducing the propagation of microcracks caused by thermal stress and improving the overall preparation quality of the silicon carbide ingot. Furthermore, by employing spherical aberration correction technology, the laser spot size inside the silicon carbide ingot can be significantly reduced, and the spot morphology improved. This not only reduces the depth of microcracks generated during processing but also reduces processing losses.

[0123] The above describes from the perspective of the light beam why the laser processing scheme of this utility model can bring about a dual improvement in efficiency and quality for the processing of silicon carbide ingots. The following will describe it from the perspective of the selection of the light source.

[0124] To more effectively control the growth region of microcracks, a specific light source can be selected; for example, the laser 110 can be a femtosecond laser. The femtosecond laser produces a small heat-affected zone when processing silicon carbide ingots 190, so microcracks hardly form outside the laser-affected zone, thus enabling precise control of microcrack growth.

[0125] The femtosecond laser includes the following laser parameters: an adjustable repetition rate of 0 to 2 MHz, an adjustable average power of 0 to 20 W, and an adjustable pulse width of 50 fs to 10 ps. During cutting, the laser beam has a pulse width of 190 fs to 350 fs, a repetition rate of 50 kHz to 500 kHz, and an average power of 1 W to 2 W. Preferably, the pulse width is 300 fs, the repetition rate is 100 kHz, and the average power is 1.5 W. At this time, each spherical aberration compensation beam has the same pulse width and repetition rate as the laser beam. Multiple spherical aberration compensation beams divide the average power of the laser beam equally. For example, each of the seven spherical aberration compensation beams has a pulse width of 300 fs, a repetition rate of 100 kHz, and an average power of 1.5 / 7 = 0.2 W.

[0126] Because the pulse width of 190 fs to 350 fs (e.g., 300 fs) is shorter than the lattice vibration time (1 ps to 100 ps), the energy deposition of a single pulse ends before the lattice vibration, thus greatly reducing the generation of thermal effects. Furthermore, a repetition frequency of 50 kHz to 500 kHz (e.g., 100 kHz) combined with a preset cutting speed of 15 mm / s to 50 mm / s (e.g., 25 mm / s) can also significantly reduce the thermal effects caused by the accumulation of multiple pulses. This reduction in thermal effects means that the growth of microcracks can be precisely controlled.

[0127] When cutting silicon carbide ingots 190, the femtosecond laser pulses generated by the femtosecond laser produce a certain thermal diffusion region. Therefore, the spacing between adjacent laser processing lines is also considered. The spacing between adjacent laser processing lines is made larger than the size of the thermal diffusion region caused by the femtosecond laser pulse, thereby reducing the superposition effect of the thermal diffusion region and enabling precise control of microcrack growth. For example... Figure 7 As shown, the spacing d between adjacent laser processing lines 210 is 30μm to 50μm, preferably 40μm.

[0128] When the focused aberration-compensated beam moves across the silicon carbide ingot 190 along a preset cutting path and at a preset cutting speed, it modifies the interior of the silicon carbide ingot 190 to form a silicon carbide modified layer (also known as a microcrack layer) 191, as shown below. Figure 8 As shown, the silicon carbide modified layer 191 serves as the base point for silicon carbide wafer separation. Combined with subsequent auxiliary dicing processes, the silicon carbide wafer can be successfully cut from the silicon carbide ingot 190.

[0129] In addition, when the focused spherical aberration compensation beam moves on the silicon carbide ingot 190, the focused spherical aberration compensation beam can not only modify the dicing path that is moving, but also produce a pre-modification effect on the adjacent dicing path that is perpendicular to the moving dicing path. This makes the growth of microcracks more uniform and controllable, thereby reducing the difficulty of subsequent dicing processes and improving the quality of silicon carbide wafers.

[0130] Therefore, in the laser processing solution of this utility model, a femtosecond laser with preset laser parameters is used, combined with a preset cutting speed and the spacing between laser processing lines, to cut silicon carbide ingots. This can also reduce the roughness generated on the surface of silicon carbide wafers, thereby improving the quality of silicon carbide wafers.

[0131] In summary, whether using a spherical aberration-compensated beam or a femtosecond laser, the goal is to concentrate the microcracks as much as possible along the cutting path. This prevents the microcracks from spreading outwards due to the heat diffusion of the laser, thus enabling precise control of microcrack growth.

[0132] In this invention, by controlling the angle (i.e., collimation), power, and optical field of the laser beam, microcracks are stably generated inside the silicon carbide ingot, and with the help of subsequent auxiliary cleaving processes, high-quality silicon carbide wafers are obtained.

[0133] The above text combined Figures 1 to 8 The embodiments of the device of this utility model are described in detail below, in conjunction with... Figure 11 The method embodiments of this utility model are described in detail below.

[0134] Figure 9 This is a schematic flowchart of a method for cutting silicon carbide ingots according to an embodiment of the present invention. The cutting method is executed by the controller 109 in the above-described apparatus embodiment; for parts not described in detail, please refer to the preceding apparatus embodiment. The cutting method includes the following:

[0135] S910: Determine the spherical aberration caused by the mismatch between the refractive index of air and the refractive index of silicon carbide ingot, and determine the spherical aberration compensation phase diagram required to compensate for the spherical aberration.

[0136] In one example, the controller determines the spherical aberration caused by the mismatch between the refractive index of air and the refractive index of silicon carbide ingot using the Zernike polynomial phase difference method described above, and then determines the spherical aberration compensation phase map required to compensate for the spherical aberration based on the GCS algorithm described above. The detailed determination process has been described above, so it will not be repeated here.

[0137] Of course, methods for determining spherical aberration are not limited to Zernike polynomial phase difference. In practical applications, those skilled in the art can flexibly choose other applicable methods according to specific needs and scenarios.

[0138] It should be understood that through step S910, the spherical aberration generated by each sub-beam after sequentially passing through air and silicon carbide ingot can be determined, and a spherical aberration compensation phase diagram corresponding to each sub-beam can be designed accordingly.

[0139] S920: Controls the spatial light modulator to load multiple spherical aberration compensation phase maps, and performs spherical aberration compensation on multiple sub-beams arranged along a preset direction based on the multiple spherical aberration compensation phase maps, and outputs multiple spherical aberration compensation beams, wherein one spherical aberration compensation phase map is used to perform spherical aberration compensation on one sub-beam.

[0140] In fact, step S910 can be considered as the process of spherical aberration correction. During this process, spherical aberration correction determines the required spherical aberration compensation amount for each sub-beam and establishes a spherical aberration compensation phase diagram. The following step S920 is the implementation stage of spherical aberration compensation. In this stage, based on the spherical aberration compensation phase diagram determined in step S910, spherical aberration compensation is performed on each sub-beam to ensure more precise beam focus. The amount of spherical aberration compensation is specifically represented by the spherical aberration compensation phase diagram.

[0141] S930: Controls multiple focused spherical aberration compensation beams to move on a silicon carbide ingot with a preset cutting path and a preset cutting speed, and modifies the interior of the silicon carbide ingot to complete the cutting of the silicon carbide ingot. The multiple focused spherical aberration compensation beams are obtained by focusing multiple spherical aberration compensation beams.

[0142] The controller controls the scanning mechanism to move the focused spherical aberration compensation beam on the silicon carbide ingot along a preset cutting path and at a preset cutting speed. During the movement of the focused spherical aberration compensation beam, the interior of the silicon carbide ingot is modified to complete the cutting of the silicon carbide ingot.

[0143] The angle between the preset direction and the first direction perpendicular to the preset cutting path is greater than or equal to 0° and less than or equal to 45°. The spacing between adjacent laser processing lines in the preset cutting path is 30μm to 50μm, and the preset cutting speed is 15mm / s to 50mm / s.

[0144] In addition, the cutting method also includes controlling the laser to output a laser beam with preset laser parameters, wherein the laser beam is split into multiple sub-beams by a beam splitting element.

[0145] The preset laser parameters include a pulse width of 190fs to 350fs, a repetition frequency of 50KHz to 500KHz, and an average power of 1W to 2W.

[0146] Therefore, in the laser cutting scheme of this invention, spherical aberration compensation is applied to multiple sub-beams arranged along a preset direction. This significantly reduces the spot size of each focused sub-beam along the optical axis inside the silicon carbide ingot, decreasing the length of the growth region for microcracks generated along the optical axis during processing. This allows for finer control during laser cutting of silicon carbide ingots, resulting in high-quality silicon carbide wafers. Furthermore, using multiple sub-beams to cut the silicon carbide ingot provides a larger coverage area because the sub-beams spread along a preset direction parallel to the cutting plane of the silicon carbide ingot, thus improving cutting efficiency. Therefore, this method brings a dual improvement in efficiency and quality to the processing of silicon carbide ingots.

[0147] The above text combined Figure 9 The method embodiments of this utility model are described in detail below, in conjunction with... Figure 10 The following describes in detail the system embodiments of this utility model. It should be understood that the description of the method embodiments corresponds to the description of the system embodiments; therefore, any parts not described in detail can be referred to the foregoing method embodiments.

[0148] Figure 10 This is a schematic diagram of a silicon carbide ingot cutting system according to an embodiment of the present invention. The cutting system 1000 may include: a determining module 1010, a first control module 1020, and a second control module 1030. These modules will be described in detail below.

[0149] The determination module 1010 is used to determine the spherical aberration caused by the mismatch between the refractive index of air and the refractive index of silicon carbide ingot, and to determine the spherical aberration compensation phase diagram required to compensate for the spherical aberration.

[0150] The first control module 1020 is used to control the spatial light modulator to load multiple spherical aberration compensation phase maps, and based on the multiple spherical aberration compensation phase maps, to perform spherical aberration compensation on multiple sub-beams arranged along a preset direction, and to output multiple spherical aberration compensation beams, wherein one spherical aberration compensation phase map is used to perform spherical aberration compensation on one sub-beam.

[0151] The second control module 1030 is used to control the scanning mechanism so that the focused spherical aberration compensation beam moves on the silicon carbide ingot with a preset cutting path and a preset cutting speed. During the movement of the focused spherical aberration compensation beam, the interior of the silicon carbide ingot is modified to complete the cutting of the silicon carbide ingot.

[0152] The cutting system 1000 may also include: a third control module for controlling the laser to output a laser beam with preset laser parameters, wherein the laser beam is split into multiple sub-beams by a beam splitting element.

[0153] Figure 11 This is a block diagram of a laser processing system provided in one embodiment of the present invention. The laser processing system 1100 may, for example, be a computing device with computational capabilities. The laser processing system 1100 may include a memory 1110 and a processor 1120 (which can be understood as the controller 109 described above). The memory 1110 can be used to store executable code. The processor 1120 can be used to execute the executable code stored in the memory 1110 to implement the steps in the various methods described above. In some embodiments, the laser processing system 1100 may further include a network interface 1130 through which data exchange between the processor 1120 and external devices can be achieved.

[0154] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any other combination. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this utility model is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. Available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid state disks (SSDs)).

[0155] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments of this utility model can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this utility model.

[0156] In the several embodiments provided by this utility model, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0157] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0158] In addition, in the various embodiments of this utility model, each functional unit can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0159] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A laser processing apparatus, characterized in that, include: A laser is used to emit a laser beam with preset laser parameters. A beam splitting element is used to split the laser beam into multiple sub-beams arranged along a preset direction; A spherical aberration compensation element is used to compensate for spherical aberration in the plurality of sub-beams and output a plurality of spherical aberration compensated beams; The scanning mechanism is used to focus the multiple spherical aberration compensation beams and use the multiple focused spherical aberration compensation beams to cut the silicon carbide ingot with a preset cutting path and a preset cutting speed.

2. The laser processing apparatus according to claim 1, characterized in that, Also includes: A controller is configured to determine spherical aberration caused by the mismatch between the refractive index of air and the refractive index of the silicon carbide ingot, and to determine a spherical aberration compensation phase map required to correct the spherical aberration, wherein the spherical aberration compensation element includes a spatial light modulator loaded with a plurality of the spherical aberration compensation phase maps, one of which is used to compensate for spherical aberration in a sub-beam.

3. The laser processing apparatus according to claim 1, characterized in that, Also includes: The controller is used to control the laser to emit the laser beam with the preset laser parameters, control the spherical aberration compensation element to perform spherical aberration compensation on the plurality of sub-beams, and control the scanning mechanism so that the plurality of focused spherical aberration compensated beams cut the silicon carbide ingot with the preset cutting path and the preset cutting speed.

4. The laser processing apparatus according to claim 1, characterized in that, Also includes: The controller includes a scanning mechanism comprising a focusing optical element and a three-axis displacement stage for carrying the silicon carbide ingot. The focusing optical element is used to focus the plurality of spherical aberration compensation beams to obtain the plurality of focused spherical aberration compensation beams. The controller controls the movement of the three-axis displacement stage so that the plurality of focused spherical aberration compensation beams cut the silicon carbide ingot at the preset cutting path and the preset cutting speed.

5. The laser processing apparatus according to claim 1, characterized in that, Also includes: The controller includes a scanning mechanism comprising a focusing optical element and a galvanometer group. The focusing optical element is used to focus the plurality of spherical aberration compensation beams to obtain the plurality of focused spherical aberration compensation beams. The controller controls the deflection angle of the galvanometer group so that the plurality of focused spherical aberration compensation beams cut the silicon carbide ingot with the preset cutting path and the preset cutting speed.

6. The laser processing apparatus according to any one of claims 1 to 5, characterized in that, The beam-splitting element includes a Dammann grating.

7. The laser processing apparatus according to any one of claims 1 to 5, characterized in that, The angle between the preset direction and the first direction perpendicular to the preset cutting path is greater than or equal to 0° and less than or equal to 45°.

8. The laser processing apparatus according to any one of claims 1 to 5, characterized in that, The preset cutting speed is 15 mm / s to 50 mm / s, and the spacing between adjacent laser processing lines in the preset cutting path is 30 μm to 50 μm.

9. The laser processing apparatus according to any one of claims 1 to 5, characterized in that, The laser includes a femtosecond laser, and the preset laser parameters include: a pulse width of 190fs to 350fs, a repetition frequency of 50kHz to 500kHz, and an average power of 1W to 2W.

10. The laser processing apparatus according to claim 9, characterized in that, The preset laser parameters include: a repetition frequency of 100 kHz, an average power of 1.5 W, and a pulse width of 300 fs.

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