Method and system for slicing silicon carbide crystal ingot by laser cutting

Abstract

The invention discloses a silicon carbide crystal ingot laser cutting fragmentation method and system, and relates to the technical field of silicon carbide laser processing. The method comprises the steps that laser parameters are set, a laser beam focus is focused at the preset depth in a silicon carbide crystal ingot to be cut, a light spot generates a cutting point at the position of the preset depth, the cutting point forms a carbonization area, and a crack area is formed around the carbonization area; a laser scanning path and parameters are set, so that the multiple cutting points are overlapped to form cutting channels, the multiple cutting channels form a cutting face, the multiple carbonization areas form a carbonization area layer, and the multiple crack areas form a crack area layer; taking the carbonization region layer as an interface, and stripping one part of the silicon carbide crystal ingot to obtain a silicon carbide wafer; and accurately grinding the silicon carbide wafer to a target roughness and a target thickness.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide laser processing, and in particular to a method and system for laser cutting and slicing of silicon carbide ingots. Background Art

[0002] Silicon carbide (SiC) is a popular power device material in the third generation of semiconductor materials. It is widely used in the production and manufacturing of traditional semiconductor industries such as IC or LSI chips, LEDs and other devices due to its advantages such as high insulation breakdown field strength, high band gap, and high temperature stability. In the new energy industry such as electric vehicles and photovoltaic solar energy, the role of silicon carbide (SiC) materials in improving product quality and efficiency is becoming more and more significant. Among them, power devices or LEDs are manufactured by stacking functional layers on silicon carbide (SiC) wafers and then dividing them into various chips.

[0003] The silicon carbide (SiC) wafers used to make devices are cut from cylindrical ingots and then double-sided polished to a mirror surface to obtain wafers. Since the silicon carbide ingot material is expensive and the ingot itself is relatively hard (Mohs hardness 9.2-9.5), traditional cutting techniques such as mortar wire cutting and diamond wire cutting cause a loss of more than 50% of the silicon carbide ingot, and there are problems such as low efficiency and high material loss rate during the processing.

[0004] In order to improve the processing efficiency of silicon carbide wafers and reduce costs, laser cutting technology has become a research hotspot.

[0005] SiC material has a high light transmittance, and the laser can focus on the set position inside the material through the surface. Under the energy of high power density laser, the material properties of the focus position inside the silicon carbide (SiC) ingot change. The entire surface can be processed by laser to form a modified layer, and the wafer can be sliced ​​and peeled from the modified layer. Laser has the characteristics of high precision, high efficiency, low loss, and low pollution. It is used to accurately and efficiently control the processing position and size when cutting ingots, greatly reducing the processing loss of silicon carbide (SiC) materials, reducing costs and improving efficiency.

[0006] At present, the application of laser cutting technology in silicon carbide wafer processing is still in the development stage, and the technology is not mature enough. For example, when the laser directly acts on a large area, the modified layer is dense, it takes a long time to complete the processing of the entire format, and the material loss is large; when the laser directly acts on a small area, the modified layer is loose, which will lead to difficulty in slicing, high roughness of the processed surface after slicing, and large subsequent fine grinding losses; there is a certain height difference in the entire format of large-size (such as 6-inch) wafer processing, resulting in inconsistent overall thickness of the cut wafers. In order to further improve processing efficiency and yield rate and reduce losses, it is necessary to optimize laser cutting technology. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for laser cutting and slicing of silicon carbide ingots, so as to improve the laser cutting efficiency and yield rate and reduce the loss.

[0008] In order to solve the above problems, the present invention proposes the following technical solutions:

[0009] A method for laser cutting and slicing a silicon carbide ingot, comprising:

[0010] Setting laser parameters, focusing the laser beam at a preset depth inside the silicon carbide ingot to be cut, generating a cutting point at the preset depth, the cutting point forming a carburized zone, and a crack zone forming around the carburized zone;

[0011] Setting the laser scanning path and parameters so that the plurality of cutting points are superimposed to form a cutting path, the plurality of cutting paths form a cutting surface, the plurality of carbonized areas form a carbonized area layer, and the plurality of crack areas form a crack area layer;

[0012] Using the carbide zone layer as an interface, peeling off a portion of the silicon carbide ingot to obtain a silicon carbide wafer;

[0013] The silicon carbide wafer is finely ground to a target roughness and a target thickness.

[0014] It can be understood that silicon carbide (SiC) ingots are generally cylindrical, and the upper and lower surfaces of the cylinder remain parallel. The incident surface of the laser beam is defined as the upper surface, which is a polished surface. The ingot relies on the positioning edge to determine the crystal orientation. During laser cutting, the laser beam is incident vertically through the upper surface into the interior of the ingot, focused at a preset depth position, and a cutting point is generated; through laser beam scanning, from point to line, from line to surface, a focusing plane is formed, and the distance between the focusing plane and the upper surface is the preset depth.

[0015] A further technical solution is that the preset depth is the sum of the target wafer thickness and the cutting margin, and the cutting margin is 10-50 μm.

[0016] Silicon carbide (SiC) at the focal point of the light spot is decomposed into C and Si under the action of high instantaneous power and high energy density of the laser. C has a higher melting point and is still in a solid state, so it appears black at the focal point, forming a carbide zone, while Si has a lower melting point and is instantly vaporized into Si vapor, which expands the internal crystal and generates cracks; therefore, a carbide zone is formed at the cutting point, and a crack zone is formed around the carbide zone.

[0017] A further technical solution is that the laser light source is: pulsed laser or continuous laser, wherein the pulse width of the pulsed laser is nanosecond, picosecond or femtosecond; the laser wavelength is 193nm-10600nm; the laser energy is 1-1000W, the frequency is 50-10000kHz; and the spot diameter is 1-150μm.

[0018] A further technical solution is that the laser light source is: a short pulse laser with a wavelength of 320nm-1080nm, a pulse width of picoseconds or femtoseconds; a power of 10-500W, a frequency of 100-3000kHz; and a spot diameter of 1-150μm.

[0019] Different wavelengths affect the ability of the laser to propagate and focus within the wafer material.

[0020] The width of the pulse laser will affect the effect of spot superposition. Ultrashort pulses (such as picosecond or femtosecond levels) can reduce the heat-affected zone and improve processing accuracy.

[0021] A further technical solution is that the laser scanning speed is 1-2000 mm / s. The preferred laser scanning speed is 50-1800 mm / s, and the more preferred laser scanning speed is 100-1500 mm / s. For example, 100 mm / s, 200 mm / s, 500 mm / s, 800 mm / s, 1000 mm / s, 1200 mm / s, 1500 mm / s.

[0022] A further technical solution is that the distance between two adjacent cutting lanes is 10-1000 μm. Preferably, the distance between two adjacent cutting lanes is 50-800 μm, more preferably 200-800 μm, and most preferably 400-800 μm.

[0023] A further technical solution is that the plurality of cutting points are superimposed to form a cutting path, and the superposition ratio N satisfies formula (1):

[0024] N=d*f / v (1)

[0025] Wherein, d is the spot diameter, f is the laser output frequency, v is the laser scanning speed, N is 0-10 and N is not 0.

[0026] It can be understood that the number of light spots per unit area is the superposition rate. According to the motion trajectory of the laser scanning, a single cutting point or a cutting line formed by superimposing multiple cutting points can be presented on the preset depth layer.

[0027] Taking the circular spot as an example, when N=1, the spots are tangent along the motion trajectory; when 0<N<1, such as N=1 / 2, the distance between the centers of adjacent spots is 2d, showing a spot left empty between two spots; when N>1, such as N=2, the action area is the superposition effect of two spots. The larger the superposition rate N, the more spots per unit area, the slower the laser scanning speed, and the lower the processing efficiency.

[0028] A further technical solution is that the stacking rate N is 1-5.

[0029] The present invention also provides a system for laser cutting and slicing of silicon carbide ingots, comprising:

[0030] An adsorption platform, used for loading the silicon carbide ingot to be cut;

[0031] A laser system is used to provide a laser beam and focus the laser beam at a preset depth inside the silicon carbide ingot to be cut, so that the light spot generates a cutting point at the preset depth, the cutting point forms a carburized zone, and a crack zone is formed around the carburized zone;

[0032] A scanning system, used for controlling the focus of the laser beam to scan at a preset depth layer of the silicon carbide ingot to be cut, wherein a plurality of the cutting points are superimposed to form a cutting path, a plurality of the cutting paths form a cutting surface, a plurality of the carbide zones form a carbide zone layer, and a plurality of the crack zones form a crack zone layer;

[0033] The separation system is used to peel off a part of the silicon carbide ingot with the carbide zone layer as an interface to generate a silicon carbide wafer.

[0034] Compared with the prior art, the technical effects achieved by the present invention include:

[0035] The method for laser cutting and slicing of silicon carbide ingots provided by the present invention reduces material loss and improves the laser action area and size spacing of the modified layer by setting laser processing parameters, so that after the laser action, it is not only conducive to the separation of the wafer from the ingot with high processing efficiency, but also can ensure that the surface roughness after processing is small and the loss is small; when the whole surface is processed, the spacing between the modified layer and the ingot surface is consistent, and the processed wafers have no width thickness difference. The method of the present invention can significantly improve the cutting efficiency and yield rate of silicon carbide (SiC) ingots, reduce the difficulty of slicing, and reduce material loss.

[0036] The system for laser cutting and slicing of silicon carbide ingots provided by the present invention is used to execute the above method, and has the effects of high processing efficiency and low material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0038] Figure 1 A schematic diagram of the structure of a system for laser cutting and slicing a silicon carbide ingot provided in an embodiment of the present invention.

[0039] Figure 2 A schematic diagram of laser processing of silicon carbide using the method for laser cutting and slicing of silicon carbide ingots provided in an embodiment of the present invention;

[0040] Figure 3 A diagram showing the actual effect of laser processing silicon carbide using the method for laser cutting and slicing of silicon carbide ingots provided in an embodiment of the present invention;

[0041] Figure 4 A schematic diagram of the cutting cross section of different silicon carbides by laser processing using the method for laser cutting and slicing of silicon carbide ingots provided in an embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a separation system in a system for laser cutting and slicing of silicon carbide ingots provided in an embodiment of the present invention;

[0043] Figure 6 A flow chart of a method for laser cutting and slicing a silicon carbide ingot provided in an embodiment of the present invention.

[0044] Reference numerals

[0045] 1. Laser; 2. First reflector; 3. Second reflector; 4. Beam expander; 5. Third reflector; 6. Objective lens; 7. Z-axis motion module; 8. Altimeter; 9. Piezoelectric ceramics; 10. Adsorption platform; 11. Silicon carbide ingot; 12. XY motion module; 13. Fixing fixture; 14 Silicon carbide wafer; 15 Separation fixture; 16 Carbide zone layer; 17. First positioning edge; 18. Second positioning edge; 19. Cutting path. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Similar component numbers in the drawings represent similar components. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0048] It should also be understood that the terms used in this description of the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present invention. As used in the description of the embodiments of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms.

[0049] It should be noted that, in the present invention, the "carbonized zone" is also referred to as a "modified zone", and the "carbonized zone layer" is also referred to as a "modified layer".

[0050] Example 1

[0051] See also Figure 1 This embodiment provides a system for laser cutting and slicing of silicon carbide ingots, which includes:

[0052] The adsorption platform 10 is used to load the silicon carbide ingot 11 to be cut.

[0053] In a specific implementation, a fixing fixture 13 for fixing the silicon carbide ingot 11 to be cut is provided on the adsorption platform 10. Specifically, the silicon carbide ingot 11 to be cut can be fixed in the fixing fixture 13 by hot melt adhesive, photosensitive adhesive or vacuum adsorption.

[0054] The silicon carbide ingot 11 is a cylindrical ingot with parallel upper and lower surfaces, and the lower surface is fixed to a fixture.

[0055] The laser system is used to provide a laser beam and focus the laser beam at a preset depth inside the silicon carbide ingot to be cut. The light spot generates a cutting point at the preset depth, and the cutting point forms a carbide zone, and a crack zone is formed around the carbide zone.

[0056] In this embodiment, the laser system includes a laser 1, a first reflector 2, a second reflector 3, a beam expander 4, a third reflector 5 and an objective lens 6; the light beam emitted by the laser 1 is a Gaussian light with normal energy distribution, and the first reflector 2, the second reflector 3, the beam expander 4 and the third reflector 5 are installed according to the requirements of the light beam transmission path. The light beam passes through the beam expander 4 to adjust the size and divergence of the light beam so that the light beam meets the incident light size requirements of the objective lens 6 and maintains parallel light incidence.

[0057] A scanning system is used to control the focus of the laser beam to scan a preset depth layer of the silicon carbide ingot to be cut, multiple cutting points are superimposed to form a cutting path, multiple cutting paths form a cutting surface, multiple carbide zones form a carbide zone layer, and multiple crack zones form a crack zone layer.

[0058] In this embodiment, the scanning system includes a Z-axis motion module 7 , an XY motion module 12 , a height meter 8 and a piezoelectric ceramic 9 .

[0059] In this embodiment, the objective lens 6 of the laser system is installed on the Z-axis motion module 7, which can realize the movement of the laser beam in the Z-axis direction.

[0060] The XY motion module 12 is connected to the adsorption platform 10 and can drive the silicon carbide ingot 11 on the adsorption platform 10 to move in the XY direction.

[0061] The objective lens 6 is a focusing lens with adjustable focal depth. In this embodiment, the spot size of the light beam at the focusing position after passing through the objective lens 6 is 1-50 μm, so that the energy density per unit area acting on the silicon carbide ingot is extremely high, which can change the crystal structure properties of silicon carbide (SiC) at the moment of laser breakdown.

[0062] During the laser processing, the objective lens 6 remains stationary in the XY direction, and the silicon carbide ingot 11 is adsorbed on the platform 10 and driven by the XY motion module 12 to move in the XY direction, so that the focused light beam acts on different positions of the same plane of the ingot, and the processing speed and positioning accuracy are determined by the performance parameters of the XY motion module 12. In this embodiment, the positioning accuracy of the XY motion module 12 is ±0.01μm, and the movement speed range is 1-2000mm / s, preferably 500-1800mm / s, and more preferably 800-1500mm / s.

[0063] In a specific embodiment, the laser incident surface of the silicon carbide ingot 11 is defined as the upper surface, which is a polished surface. The ingot relies on the positioning edge to determine the crystal orientation. During laser cutting, the light beam is vertically incident and enters through the upper surface into the ingot to focus at a preset depth. The silicon carbide ingot 11 is driven to move in the same plane through the XY motion module 12, thereby forming a focusing plane. The focusing plane is parallel to the upper surface, and the distance between the two is the preset depth, which is generally the sum of the target wafer thickness and the processing allowance, and the processing allowance is 10-50μm.

[0064] like Figure 2As shown, in this embodiment, the silicon carbide ingot 11 is positioned by the first positioning edge 17 and the second positioning edge 18, the first positioning edge 17 and the second positioning edge 18 are perpendicular to each other and consistent with the XY movement direction. In other embodiments, the XY movement direction can also be inclined to the positioning edge, or in a circular, bow-shaped, spiral, concentric circle, etc. scanning path, which does not affect the cutting and slicing effect.

[0065] When the system of this embodiment is in operation, the silicon carbide (SiC) at the focal plane is rapidly decomposed into C and Si under the action of the high instantaneous power and high energy density laser. C has a higher melting point and is still in solid state, so the processing area appears black, forming a carbide zone, while Si has a lower melting point and instantly vaporizes into Si steam to prop up the internal crystal to produce cracks, forming a crack zone around the carbide zone. The trajectory of the continuous action of the laser is set according to the output parameters of the XY motion module 12 and the laser 1, and multiple cutting points with intervals appear at the focal plane of the silicon carbide ingot 11, or multiple cutting points are superimposed due to small intervals to form a cutting path 19. The number of light spots per unit area is the superposition rate N of the light spots on the material.

[0066] The stacking rate N is generally calculated by formula (1):

[0067] N=d*f / v (1)

[0068] Where d is the spot diameter, f is the laser frequency, v is the movement speed, and N is 0-10 and not 0.

[0069] like Figure 3 As shown in the figure, it is the processing effect under the condition of high superposition of multiple cutting points in the Y direction. The area with property changes after processing is composed of the carbonized area in the center of the cutting point and the crack area at the edge of the cutting point. The carbide area is the modified area where the laser is directly focused. The line width is similar to the theoretical focused spot size and is dark black. The crack area is the deformation area caused by the gasification and expansion of the material during processing. The size of the area is related to the material properties of the silicon carbide (SiC) ingot and generally does not change with the carbide area. When the carbide area is subjected to external effects, such as tension, ultrasonic vibration or heating, the surrounding crack area will undergo extended fracture, so that the entire chip is separated from the ingot.

[0070] The distance between two adjacent cutting paths 19 is g. It can be understood that when the interval g is less than or equal to the spot diameter d, the entire processing surface becomes a carbonized zone modified layer. At this time, it is easy to slice the wafer out, but the overly concentrated and repeated energy action increases the thickness of the modified layer, increases material loss, and the wafer is prone to produce hidden crack fragments, which reduces the yield. At the same time, the dense scanning path reduces production efficiency, and it may take several hours to process a 6-inch wafer. When the interval g is too large, the reserved area accounts for a large proportion, and it is impossible to extend the fracture through sufficient cracks during slicing, making slicing very difficult or even impossible.

[0071] The stacking rate N and the interval g determine the speed of the entire processing format. The smaller the stacking rate N, the larger the interval g, and the higher the processing efficiency; conversely, the larger the stacking rate N, the smaller the interval g, and the lower the processing efficiency. Therefore, under different laser parameter conditions, by optimizing the interval g and stacking rate N parameters, the laser processing effect of high efficiency, low loss, easy slicing, and high yield can be achieved.

[0072] During actual processing, when the surface of the silicon carbide ingot is undulating or the levelness is insufficient, the height of the modified layer will be uneven, and the thickness of the cut wafers will vary greatly. In this embodiment, the altimeter 8 and the piezoelectric ceramic 9 form a height tracking module. The altimeter 8 and the piezoelectric ceramic 9 are arranged on the Z-axis motion module 7. The altimeter 8 is a capacitive sensor, which can sense the distance change between the objective lens 6 and the surface of the silicon carbide ingot 11 to be cut, and feed back this distance (height) information to the piezoelectric ceramic in real time. The piezoelectric ceramic adjusts the position of the objective lens 6 in real time according to this feedback information, and performs precise displacement to keep the laser focus at the ideal position of the preset depth. The altimeter 8 and the piezoelectric ceramic 9 of this embodiment can achieve micron-level height adjustment, with a control accuracy of ±1μm, which can effectively ensure the consistency of the height of the preset depth to achieve better cutting uniformity.

[0073] The separation system is used to peel off a part of the silicon carbide ingot with the carbide zone layer as an interface to generate a silicon carbide wafer.

[0074] See also Figure 5 The separation system of this embodiment includes a separation jig 15. Specifically, the separation jig 15 is set on the silicon carbide wafer 14 to be peeled off, and the separation jig 15 is connected to a mechanical structure to apply a pulling force perpendicular to the wafer surface, a tangential force parallel to the wafer surface, and a torque coaxial with the wafer circle. Under the action of a single directional force or a composite force, the silicon carbide wafer 14 is split at the interface of the carbide zone layer 16 to obtain a silicon carbide wafer 14 with a rough lower surface.

[0075] It can be understood that the silicon carbide ingot laser cutting and slicing system of this embodiment can be installed on a rack or a marble platform base according to actual conditions, and can be adjusted to keep all elements incident with the laser on the same optical axis, so that the light beam meets the incident light size requirements of the objective lens 6 and maintains parallel light incidence.

[0076] Example 2

[0077] See also Figure 6 , which is a flow chart of the method for laser cutting and slicing of silicon carbide ingots provided in this embodiment.

[0078] This embodiment provides a method for laser cutting and slicing a silicon carbide ingot, comprising:

[0079] Setting laser parameters, adjusting the optical path, focusing the laser beam at a preset depth inside the silicon carbide ingot to be cut, generating a cutting point at the preset depth, the cutting point forming a carburized zone, and a crack zone forming around the carburized zone;

[0080] Setting the laser scanning path and parameters so that the plurality of cutting points are superimposed to form a cutting path, the plurality of cutting paths form a cutting surface, the plurality of carbonized areas form a carbonized area layer, and the plurality of crack areas form a crack area layer;

[0081] Using the carbide zone layer as an interface, peeling off a portion of the silicon carbide ingot to obtain a silicon carbide wafer;

[0082] The silicon carbide wafer is finely ground to a target roughness and a target thickness.

[0083] In a specific implementation, the laser light source is: a pulsed laser or a continuous laser, wherein the pulse width of the pulsed laser is nanoseconds, picoseconds or femtoseconds; the laser wavelength is 193nm-10600nm; the laser energy is 1-1000W, the frequency is 50-10000kHz; and the spot diameter is 1-150μm.

[0084] In a preferred embodiment, the laser light source is: a short pulse laser with a wavelength of 320nm-1080nm, a pulse width of picoseconds or femtoseconds; a power of 10-500W, a frequency of 100-3000kHz; and a spot diameter of 1-50μm.

[0085] The laser light source of this embodiment is: a short pulse laser with a wavelength of 355nm and a pulse width of picoseconds; a power of 50W and a frequency of 800kHz; and a spot diameter of 30μm.

[0086] The laser scanning speed of this embodiment is 1500 mm / s.

[0087] Table 1 shows the processing effect of optimizing the interval g and the stacking ratio N under the laser parameters of the above embodiment.

[0088] Table 1 shows the processing effects of the embodiments with different intervals g and stacking ratios N.

[0089]

[0090] In the table, "x" means that the modified layer cannot be formed, "-" means that the modified layer thickness is less than 10μm and it is difficult to slice and the yield is low, "=" means that the modified layer thickness is 10-20μm and the effect is good, "+" means that the modified layer is greater than 20μm and the material loss is large; "◇" means that the material loss is too large and cannot be processed.

[0091] The larger the stacking rate N is, the slower the laser scanning speed is and the lower the processing efficiency is. The larger the interval g is, the smaller the overall processing area is and the higher the processing efficiency is.

[0092] Considering the processing efficiency, yield rate and loss rate, under the above laser conditions, when the stacking rate N is 1, the interval g is 100-200μm; when the stacking rate N is 2, the interval g is 400-600μm; when the stacking rate N is 5, the interval g is 600-800μm; therefore, when the stacking rate N is preferably 1-5 and the interval g is 400-800μm, the processing effect and efficiency are optimal. According to the method in this patent, the optimal solution can be obtained by testing and adjusting lasers with different parameters.

[0093] It is understandable that, depending on the different wafer growth methods, the silicon carbide (SiC) ingot has an off-angle of 0-4°, which is called the α angle. For example, to obtain the desired low-defect 4H-SiC, the SiC wafer usually needs to be grown on the seed lattice with an off-axis of 4°. When cutting in the direction perpendicular to the flat edge of the wafer, the crack will have a 4° off-angle with the upper surface or the focusing plane. The laser cutting method of the present invention is applicable to ingots with different α angles. Figure 4 As shown in the figure, a is a schematic diagram of the cutting section when the lattice growth α=4°; b is a schematic diagram of the cutting section when the lattice growth α=0°; c is a schematic diagram of the cutting section with undulations on the ingot surface; d is a schematic diagram of the cutting section with insufficient leveling accuracy of the processing plane.

[0094] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0095] The above is a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for laser cutting and slicing a silicon carbide ingot, characterized in that: include: Setting laser parameters, focusing the laser beam at a preset depth inside the silicon carbide ingot to be cut, generating a cutting point at the preset depth, the cutting point forming a carburized zone, and a crack zone forming around the carburized zone; Setting the laser scanning path and parameters so that the plurality of cutting points are superimposed to form a cutting path, the plurality of cutting paths form a cutting surface, the plurality of carbonized areas form a carbonized area layer, and the plurality of crack areas form a crack area layer; Using the carbide zone layer as an interface, peeling off a portion of the silicon carbide ingot to obtain a silicon carbide wafer; The silicon carbide wafer is finely ground to a target roughness and a target thickness.

2. The method for laser cutting and slicing of silicon carbide ingots according to claim 1, characterized in that: The preset depth is the sum of the target thickness and the cutting margin, and the cutting margin is 10-50 μm.

3. The method for laser cutting and slicing of silicon carbide ingots according to claim 1, characterized in that: The laser light source is: pulse laser or continuous laser, wherein the pulse width of the pulse laser is nanosecond, picosecond or femtosecond; the laser wavelength is 193nm-10600nm; the laser energy is 1-1000W, the frequency is 50-10000kHz; and the spot diameter is 1-150μm.

4. The method for laser cutting and slicing of silicon carbide ingots according to claim 3, characterized in that: The laser light source is: a short pulse laser with a wavelength of 320nm-1080nm, a pulse width of picoseconds or femtoseconds, a power of 10-500W, a frequency of 100-3000kHz, and a spot diameter of 1-50μm.

5. The method for laser cutting and slicing of silicon carbide ingots according to claim 1, characterized in that: The laser scanning speed is 1-2000mm / s.

6. The method for laser cutting and slicing of silicon carbide ingots according to claim 1, characterized in that: The distance between two adjacent cutting lines is 10-1000 μm.

7. The method for laser cutting and slicing of silicon carbide ingots according to claim 6, characterized in that: The distance between two adjacent cutting lines is 200-800 μm.

8. The method for laser cutting and slicing of silicon carbide ingots according to claim 1, characterized in that: The plurality of cutting points are superimposed to form a cutting path, and the superposition ratio N satisfies the formula (1): N=d*f / v (1) Wherein, d is the spot diameter, f is the laser output frequency, v is the laser scanning speed, and N is 0-10 and is not 0.

9. The method for laser cutting and slicing of silicon carbide ingots according to claim 8, characterized in that: The stacking ratio N is 1-5.

10. A system for laser cutting and slicing of silicon carbide ingots, characterized in that: include: An adsorption platform, used for loading the silicon carbide ingot to be cut; A laser system is used to provide a laser beam and focus the laser beam at a preset depth inside the silicon carbide ingot to be cut, so that the light spot generates a cutting point at the preset depth, the cutting point forms a carburized zone, and a crack zone is formed around the carburized zone; A scanning system, used for controlling the focus of the laser beam to scan at a preset depth layer of the silicon carbide ingot to be cut, wherein a plurality of the cutting points are superimposed to form a cutting path, a plurality of the cutting paths form a cutting surface, a plurality of the carbide zones form a carbide zone layer, and a plurality of the crack zones form a crack zone layer; The separation system is used to peel off a part of the silicon carbide ingot with the carbide zone layer as an interface to generate a silicon carbide wafer.

Images