A method for cutting a silicon carbide boule

Abstract

The application discloses a cutting method of a silicon carbide crystal bar, which comprises the following steps: providing a crystal bar to be cut, the crystal bar having a circular arc-shaped outer circumferential surface extending along an axial direction; determining an entry point of the crystal bar in a cutting direction, and bonding a sacrificial component at the entry point, the sacrificial component covering the entry point and extending along the axial direction of the crystal bar, and the bonding agent forming a rigid adhesive layer; and controlling a cutting wire mesh to feed in a direction perpendicular to the axial direction of the crystal bar, so that the cutting wire mesh first cuts into the sacrificial component and then cuts into the inside of the crystal bar, the material of the sacrificial component being the same as that of the crystal bar, or the Vickers hardness of the sacrificial component and the Vickers hardness of the crystal bar having an absolute value of a deviation less than a preset threshold value, so that the continuity of cutting stress is maintained when the cutting wire mesh cuts into the crystal bar from the sacrificial component, the entry line marks caused by axial movement of the cutting wire are avoided, the deformation amount of a wafer at the entry position is reduced, the wafer warping degree and bending degree are effectively reduced, and the probability of additional repair is reduced, so that the wafer direct scrapping problem caused by the line marks is solved.

Description

Technical Field

[0001] This application relates to the field of wafer processing technology, and more specifically, to a method for cutting silicon carbide crystal rods. Background Technology

[0002] Silicon carbide has a Mohs hardness of 9.2, classifying it as an ultra-hard material, second only to diamond. Therefore, only diamond-based tools can be used for cutting, resulting in extremely slow cutting speeds. Furthermore, as the diameter of the grown SiC crystals increases, the cutting time also becomes increasingly longer. In addition, the SiC substrate material requires the cut wafers to possess low warpage and low curvature after polishing, along with a low total thickness variation, further increasing the processing difficulty of the cut silicon carbide wafers.

[0003] Currently, the industry commonly uses direct feed to cut crystal rods, but this method has significant drawbacks: due to the characteristics of the cutting process, the feed speed at the entry point is faster than in the middle area, and silicon carbide itself has extremely high hardness, making it difficult for the cutting wire to directly cut into the crystal rod. It is prone to axial movement on the outside of the crystal rod, resulting in extremely unstable state of the cutting wire during the cutting process. This directly causes deep line marks at the entry point of the wafer, with a depth of 50~100μm and a maximum radial depth of 10mm. In addition, the wafer deformation in the entry area increases, causing warping. Subsequent grinding and polishing processes cannot repair such line marks, which will lead to the direct scrapping of the wafer. Even if the warp value is repaired, it is extremely difficult, seriously affecting production yield and efficiency. Summary of the Invention

[0004] One objective of this application is to provide a method for cutting silicon carbide ingots to solve the problem of warping on one side of the wafer at the cutting position.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: a method for cutting a silicon carbide crystal rod, comprising: S100, providing a crystal rod to be cut, the crystal rod having an arc-shaped outer peripheral surface extending along the axial direction; S200, determining the entry vertex of the crystal rod in the cutting direction, and bonding a sacrificial component at the entry vertex, the sacrificial component covering the entry vertex and extending along the axial direction of the crystal rod, the adhesive forming a rigid adhesive layer; S300, controlling the cutting wire mesh to feed in a direction perpendicular to the axial direction of the crystal rod, so that the cutting wire mesh first cuts into the sacrificial component, and then cuts into the interior of the crystal rod, wherein the material of the sacrificial component is the same as the material of the crystal rod, or the absolute value of the deviation between the Vickers hardness of the sacrificial component and the Vickers hardness of the crystal rod is less than a preset threshold, so as to maintain the continuity of cutting stress when the cutting wire mesh cuts into the crystal rod from the sacrificial component.

[0006] As a preferred option, in step S300, the preset threshold is 200HV.

[0007] As another preferred embodiment, the thickness H of the sacrificial component along the cutting direction satisfies: 3mm≤H≤10mm.

[0008] Further preferably, in step S200, when bonding the sacrificial component, the thickness of the adhesive layer is controlled to be less than 20 μm.

[0009] Further preferably, the thickness of the adhesive layer is controlled between 2μm and 10μm, and the Shore hardness D of the adhesive layer is greater than 80.

[0010] More preferably, the sacrificial assembly includes a plurality of sacrificial blocks arranged along the circumference of the crystal rod, wherein the sacrificial block located in the middle covers the cutting edge, and the sacrificial blocks located on both sides are inclined relative to the sacrificial block located in the middle, such that the bottom surfaces of the plurality of sacrificial blocks together fit the arc-shaped outer circumferential surface of the crystal rod.

[0011] Further preferably, the sacrificial block is made of silicon carbide waste, and its cross-section perpendicular to the crystal rod axis is rectangular.

[0012] Further preferably, there is a gap between two adjacent sacrificial blocks, the width of the gap is 0.5mm to 4mm, and the length of each sacrificial block in the circumferential direction is 5mm to 30mm.

[0013] Further preferably, the number of sacrificial blocks is 3, the middle sacrificial block is horizontally arranged, and the tilt angle α of the two side sacrificial blocks relative to the middle sacrificial block satisfies: 10°≤α≤20°.

[0014] Further preferably, the sacrificial component is an integral arc-shaped block, which is formed by sintering silicon carbide powder in a mold. The side of the arc-shaped block facing the crystal rod has a concave arc surface, and the radius of curvature of the concave arc surface is equal to the radius of curvature of the arc-shaped outer circumference of the crystal rod, so as to achieve gapless bonding.

[0015] Compared with the prior art, the beneficial effects of this application are as follows:

[0016] (1) The sacrificial component and the crystal rod are made of the same material and have the same hardness. When the cutting line cuts into the sacrificial component first, the cutting line offset can be corrected before cutting into the crystal rod, avoiding the entry line marks caused by the axial movement of the cutting line when directly cutting in. At the same time, the deformation of the wafer at the entry position is reduced, effectively reducing the wafer warpage and bending, reducing the probability of additional rework, so as to solve the problem of wafer scrapping caused by line marks and greatly improve the product yield.

[0017] (2) Only the sacrificial component needs to be bonded at the entry position of the crystal rod. There is no need to modify the existing cutting equipment or adjust the core process parameters. The operation is more convenient. The sacrificial component adopts a separable fixing method. After cutting, the residual part of the sacrificial component is removed to obtain the wafer. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the crystal rod bonded to the crystal holder provided in this application.

[0019] Figure 2 This is a schematic cross-sectional view of the crystal rod provided in Embodiment 1 of this application after the sacrificial component is bonded, along the central axis.

[0020] Figure 3 This is a schematic cross-sectional view of the crystal rod provided in Embodiment 2 of this application after the sacrificial component is bonded, along the central axis.

[0021] Figure 4 This is an inspection image of the wafer obtained after cutting and polishing during the execution of the steps in Example 1.

[0022] Figure 5 This is an inspection image of the wafer obtained after cutting and polishing during the steps of Comparative Example 1.

[0023] In the diagram: 10, crystal rod; 11, crystal; 20, sacrificial component; 21, sacrificial block; 22, arc block; 30, crystal holder. Detailed Implementation

[0024] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0025] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0026] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0027] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0028] In the accompanying drawings of this application, the X-axis and Z-axis are coordinate axes of a spatial rectangular coordinate system. The central axis direction, as mentioned below, is parallel to the X-axis, and the first direction is parallel to the Z-axis. Therefore, the Z-axis direction is the first direction, which is also the feed direction of the cutting line. The X-axis direction is the central axis direction, and the first direction is perpendicular to the central axis direction. It is understood that the coordinate system can be flexibly set according to actual needs and is not limited here.

[0029] This application provides a method for cutting a silicon carbide crystal rod 10, including:

[0030] S100, Provide a crystal rod 10 to be cut, the crystal rod 10 having an arc-shaped outer peripheral surface extending along the axial direction;

[0031] S200. Determine the entry point of the crystal rod 10 in the cutting direction, and attach the sacrificial component 20 at the entry point. The sacrificial component 20 covers the entry point and extends along the axial direction of the crystal rod 10. The adhesive forms a rigid adhesive layer.

[0032] S300: Control the cutting wire mesh to feed in a direction perpendicular to the axial direction of the crystal rod 10, so that the cutting wire mesh first cuts into the sacrificial component 20 and then into the interior of the crystal rod 10. The material of the sacrificial component 20 is the same as that of the crystal rod 10, or the absolute value of the deviation between the Vickers hardness of the sacrificial component 20 and the Vickers hardness of the crystal rod 10 is less than a preset threshold, so as to maintain the continuity of cutting stress when the cutting wire mesh cuts into the crystal rod 10 from the sacrificial component 20.

[0033] The main problem faced by existing technologies in cutting ultra-hard materials such as silicon carbide is that when diamond wires contact the surface of the arc-shaped crystal rod 10, due to the small contact area and the smooth and high hardness of the surface, the cutting wire is prone to axial slippage, resulting in deep marks and warping at the wafer entry point. If soft materials such as resin are used as sacrificial blocks 21, the cutting resistance will surge instantly when the cutting wire transitions from the soft material to the ultra-hard silicon carbide crystal rod. This "stress mutation" will cause the taut cutting wire to vibrate violently, which may cause new marks or chipping at the interface.

[0034] The technical solution provided in this application firstly solves the problem of slippage during cutting by utilizing the "racetrack effect" of the sacrificial component 20. The sacrificial component provides a pre-cut "racetrack" for the cutting wire. Before cutting into the crystal rod 10, the cutting wire has already completed its cutting action in the sacrificial component 20, and the bow angle and tension of the cutting wire are stabilized, eliminating axial lateral sway. When the cutting wire reaches the crystal rod 10, it is already in a stable straight cutting state, thus avoiding slippage when directly contacting the arc surface. Secondly, this application solves the problem of stress abrupt change by matching the hardness of the sacrificial component 20 and the crystal rod 10, ensuring that the sacrificial component 20 and the crystal rod 10 have almost identical cutting resistance. When the cutting wire transitions from the sacrificial component 20 to the crystal rod 10, the material changes almost without any change.

[0035] It is worth mentioning that the preset threshold is preferably 200HV, since the Vickers hardness of the crystal rod 10 is usually between 2600HV and 3000HV. This deviation range can ensure that the cutting resistance of the sacrificial component 20 and the crystal rod 10 are consistent, and avoid sudden stress changes.

[0036] Furthermore, when bonding the sacrificial component 20, the thickness of the adhesive layer is controlled to be less than 20 μm. It is important to understand that conventional bonding methods often use a large amount of adhesive to increase bond strength, resulting in an excessively thick adhesive layer. This excessively thick layer acts as a flexible buffer layer. When the wire mesh passes through, the adhesive layer undergoes plastic deformation due to the cutting pressure of the diamond particles, causing a sudden decrease in cutting resistance and resulting in inertial vibration of the wire mesh. Subsequently, when cutting into the high-hardness crystal rod 10, the resistance suddenly increases, creating a stress abrupt change that disrupts the stability of the wire mesh's spiral. Conversely, the adhesive layer cannot be too thin. If it is too thin, it cannot adequately fill the tiny gaps between the sacrificial component 20 and the crystal rod 10, leading to weak bonding. During cutting, vibration can cause the sacrificial component 20 to shift, disrupting the spiral's return path and resulting in marks and warping.

[0037] In a preferred embodiment, the thickness of the adhesive layer is controlled between 2μm and 10μm, which ensures the stability of the bond and avoids affecting the connection of the cutting stress. The rigid, extremely thin adhesive layer makes the sacrificial component 20 and the crystal rod 10 mechanically integrated. When the cutting line passes through the adhesive layer interface, the cutting stress is continuously transmitted without any breaks. This ensures that the cutting line can transition as smoothly as cutting a whole piece of silicon carbide.

[0038] Preferably, the adhesive layer is formed by curing high-temperature resistant epoxy resin, and the Shore hardness D of the adhesive layer is greater than 80. The temperature resistance range of the high-temperature resistant epoxy resin is not lower than 120℃, and its shrinkage rate after curing is ≤0.5%. The adhesive layer is made of rigid epoxy resin with a Shore hardness D greater than 80, and the thickness is controlled at the micron level. This can effectively transmit cutting force and avoid micro-vibration of the cutting line caused by elastic deformation of the adhesive layer. Moreover, the high-hardness adhesive layer can maintain the relative position of the sacrificial component 20 and the crystal rod 10, and the sacrificial component 20 will not shift due to deformation of the adhesive layer during the cutting process.

[0039] In some embodiments, the crystal rod 10 to be cut in step S100 is formed by bonding multiple crystals 11 together with paraffin wax, such as Figure 1 As shown, each crystal 11 has a Si surface and a C surface. The Si surface of the first crystal 11 is bonded to the C surface of the second crystal 11 to form a crystal rod 10. Then, the surface of the crystal rod 10 is wiped with alcohol or a degumming agent to remove the residual paraffin on the outer peripheral surface of the crystal rod 10. The cleaned crystal rod 10 is then indirectly bonded to the crystal holder 30. After it has cured, step S200 is performed.

[0040] The thickness H of the sacrificial component 20 along the cutting direction satisfies 3mm≤H≤10mm. The crystal rod 10 is made of silicon carbide, which is an ultra-hard material. The spiral deviation of the cutting wire mesh needs a certain effective cutting length to return to the correct position. The effective cutting length is related to the thickness of the sacrificial component 20. If the thickness of the sacrificial component 20 is too thin, the spiral will not be fully corrected before it cuts into the crystal rod 10, which will still lead to entry marks and warping. If the thickness of the sacrificial component 20 is too large, although the spiral can be corrected, it will increase unnecessary processing time and material consumption.

[0041] The sacrificial component 20 of this application can be implemented in various ways, such as Figure 2 and Figure 3 As shown.

[0042] According to one embodiment of the sacrificial assembly 20, the sacrificial assembly 20 includes a plurality of sacrificial blocks 21 arranged circumferentially along the crystal ingot 10. The middle sacrificial block 21 covers the entry point of the crystal ingot 10, and the sacrificial blocks 21 on both sides are inclined relative to the middle sacrificial block 21, such that the bottom surfaces of the plurality of sacrificial blocks 21 together fit to at least a portion of the outer peripheral surface of the crystal ingot 10. There is a gap between adjacent sacrificial blocks 21, the width of which is 0.5 mm to 4 mm. Specifically, the number of sacrificial blocks 21 can be 2, 3, 4, 5, or more. Figure 2In the illustrated embodiment, the sacrificial component 20 includes three sacrificial blocks 21. It is understood that the sacrificial blocks 21 are made from silicon carbide scrap. During the dicing process of silicon carbide wafers, a large amount of scrap, cut-off material, and other waste is generated. Processing this waste into sacrificial blocks 21 eliminates the need to purchase new silicon carbide blanks, directly converting the waste into functional components. This significantly reduces the manufacturing cost of the sacrificial component 20, making it particularly suitable for mass production scenarios. Furthermore, since the scrap and the ingot 10 to be diced are both made of silicon carbide, their crystal structure, hardness, density, and other performance parameters are completely identical. The cutting resistance is highly matched to that of the ingot 10, fundamentally avoiding sudden changes in cutting stress caused by hardness differences and ensuring stable spiral return performance.

[0043] Furthermore, such as Figure 2 As shown, the cross-section of the sacrificial block 21 along the central axis is rectangular. Although the rectangular sacrificial block 21 has a poor adhesion effect to the surface of the crystal rod 10, its processing cost is much lower than the cost of processing the sacrificial block 21 into an arc surface. Furthermore, by splicing together multiple small-sized sacrificial blocks 21 to form the sacrificial assembly 20, the aforementioned technical problems can be effectively solved.

[0044] The sacrificial block 21 has a circumferential length of 5mm to 30mm, and the sacrificial block 21 in the middle has a circumferential length equal to that of the sacrificial blocks 21 on both sides.

[0045] like Figure 2 As shown, the sacrificial block 21 in the middle is set horizontally, and the tilt angle α of the sacrificial blocks 21 on both sides relative to the sacrificial block 21 in the middle satisfies: 10°≤α≤20°. That is, the cross section of the crystal rod 10 has a center point, the cross section of the three sacrificial blocks 21 has a geometric center, and the line connecting the geometric center of the cross section of two adjacent sacrificial blocks 21 with the center point forms an included angle α.

[0046] Furthermore, the highest points of the three sacrificial blocks 21 are located on the same straight line, ensuring that the cutting wire mesh receives uniform and stable cutting force when it first contacts the sacrificial component 20. The cutting wire mesh is fed at a constant speed along a first direction perpendicular to the central axis of the crystal ingot 10, and the cutting trajectory of the cutting wire mesh must remain perpendicular to the central axis of the crystal ingot 10. If the highest points of the three sacrificial blocks 21 are not on the same straight line, the cutting wire mesh will contact the highest sacrificial block 21 first, and then the lower sacrificial block 21. This will cause a sudden change in local force on the cutting wire mesh, and the wire mesh, which should have cut smoothly, will be pulled laterally due to uneven local force, causing the spiral line to deviate prematurely. When the highest points of the three sacrificial blocks 21 are collinear, the cutting wire mesh can contact the tops of the three sacrificial blocks 21 simultaneously, the cutting resistance is evenly distributed along the contact line, and the cutting wire mesh cuts in a flat state. After cutting, the remaining part of the sacrificial component 20 is removed to obtain a circular wafer, which is then processed.

[0047] Furthermore, such as Figure 2 As shown, the surfaces where the sacrificial blocks 21 on both sides are bonded to the crystal rod 10 are called the bonding bottom surfaces. The bonding bottom surfaces have a bottom center. The bonding points between the sacrificial blocks 21 on both sides and the crystal rod 10 do not coincide with the bottom center, so that the highest points of the three sacrificial blocks 21 are located on the same straight line.

[0048] According to another embodiment of the sacrificial component 20, such as Figure 3 As shown, the sacrificial component 20 is implemented as an integral arc-shaped block 22. The side of the arc-shaped block 22 facing the crystal rod 10 has a concave arc surface. The radius of curvature of the concave arc surface is equal to the radius of curvature of the arc-shaped outer peripheral surface of the crystal rod 10, so as to achieve a gapless fit between the arc-shaped block 22 and the outer peripheral surface of the crystal rod 10.

[0049] Furthermore, the thickness of the arc-shaped block 22 along the cutting direction is 3mm~10mm, so that the cutting wire mesh is straightened before cutting into the crystal ingot 10, avoiding warping and wire marks at the cutting tip. Figure 3 As shown, the lines connecting the two endpoints of the arc-shaped block 22 to the center of the crystal rod 10 form an included angle β, which satisfies 30°~60°.

[0050] Furthermore, the arc-shaped block 22 is sintered from silicon carbide powder in a mold. In one specific embodiment, the sintering raw materials include: industrial-grade α-silicon carbide powder and molding aids. The industrial-grade α-silicon carbide powder has a purity ≥98%, a particle size of 10~50μm, and a hardness close to that of single-crystal silicon carbide, which has a Vickers hardness of 2600~3000HV, to ensure that the hardness of the arc-shaped block 22 after sintering meets a preset threshold. Then, the silicon carbide powder and silicon powder are wet-mixed in a ball mill using alcohol as the medium, with a mass fraction ratio of silicon carbide powder to silicon powder of (70~80):(20~30). The molding aid can be selected as paraffin wax or phenolic resin to improve the strength of the arc-shaped block 22 preform and prevent cracking during subsequent processing.

[0051] A custom mold is made according to the dimensions of the arc-shaped block 22, using cold isostatic pressing at a pressure of 150~200MPa, or conventional molding at a pressure of 50~100MPa, with the blank density controlled at 2.5~2.7g / cm³. 3During the process, after the preform is formed, the forming aids are removed from the preform. The preform is then placed in a box furnace or tube furnace, and the heating rate is controlled at 5℃ / min to avoid cracking due to excessive heating. The temperature is raised to 400℃ and held for 2-3 hours. Sufficient holding time ensures that the forming aids are completely removed, with a residual amount of forming aids ≤0.1%. Finally, sintering is performed at a temperature of 1450-1600℃ for 2-4 hours, causing the silicon powder to melt into a liquid state and penetrate into silicon carbide. The resulting arc-shaped block 22 has a Vickers hardness of 2400-3200 HV, and the absolute value of the deviation from the Vickers hardness of the crystal rod 10 meets the preset threshold.

[0052]

Example 1

[0053] Cut silicon carbide ingots according to the following steps:

[0054] (1) Multiple crystals 11 are bonded together with paraffin wax. The Si surface of the previous crystal 11 is bonded to the C surface of the next crystal 11 to form a crystal rod 10. Then, the surface of the crystal rod 10 is wiped with alcohol or degumming agent to remove the residual paraffin wax on the outer peripheral surface of the crystal rod 10. The cleaned crystal rod 10 is then indirectly bonded to the crystal holder 30.

[0055] (2) Provide three sacrificial blocks 21 of the same size. Each sacrificial block 21 has a rectangular cross section perpendicular to the axial direction. The width of the sacrificial block 21 is 10 mm, the thickness is 5 mm, and the axial length is consistent with the cutting length. After determining the entry point of the crystal rod 10, a sacrificial block 21 is bonded at the entry point. Then, two other sacrificial blocks 21 are bonded to both sides of the sacrificial block 21. There is a gap between the two adjacent sacrificial blocks 21. The width of the gap is 0.5 mm. The tilt angle α of the sacrificial blocks 21 on both sides relative to the middle sacrificial block 21 is 10°. The adhesive forms a rigid adhesive layer with a thickness of about 3 μm.

[0056] (3) Control the cutting wire mesh to feed at a constant speed in a direction perpendicular to the axial direction of the crystal rod 10, so that the cutting wire mesh cuts into the sacrificial component 20 and then into the interior of the crystal rod 10.

[0057]

Example 2

[0058] The difference between Example 2 and Example 1 is that in step (2): an arc-shaped block 22 formed by sintering silicon carbide powder is provided. The absolute value of the Vickers hardness deviation between the arc-shaped block 22 and the Vickers hardness of the crystal rod is less than 150 HV. The thickness of the arc-shaped block 22 is 5 mm. The line connecting the two ends of the arc-shaped block 22 and the center of the cross section of the crystal rod 10 along the central axis forms an angle β, which is 45°. After determining the entry point of the crystal rod 10, only the arc-shaped block 22 is bonded at the entry point. The adhesive forms a rigid adhesive layer with a thickness of about 3 μm.

[0059]

Example 3

[0060] The difference between Example 3 and Example 1 is that in step (2): only one sacrificial block 21 is provided. After determining the entry point of the crystal rod 10, only one sacrificial block 21 is attached at the entry point.

[0061]

Example 4

[0062] The difference between Example 4 and Example 1 is that in step (2), the thickness of the adhesive layer is about 1 μm.

[0063]

Example 5

[0064] The difference between Example 5 and Example 1 is that in step (2), the thickness of the adhesive layer is about 10 μm.

[0065]

Example 6

[0066] The difference between Example 6 and Example 1 is that in step (2), the thickness of the adhesive layer is about 20 μm.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that step (2) is omitted.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Example 2 is that the material of the sacrificial block 21 is replaced with a ceramic-reinforced resin material with a Vickers hardness of about 80~100HV.

[0071] After the crystal rods were cut using the cutting methods described in the above embodiments and comparative examples, various surface shape tests were performed on the wafers. The test results are shown in Table 1.

[0072] Table 1

[0073]

[0074] Comparing the data from Examples 1-6 and Comparative Example 1, it can be seen that the bonding sacrificial component 20 can significantly reduce the warpage and bending of the wafer, wherein... Figure 4 What is shown is an inspection image of the wafer obtained after cutting and polishing during the execution of the steps in Example 1. Figure 5 The image shown is a test image of the wafer obtained after cutting and polishing when performing the steps of Comparative Example 1. It can be seen that even if the wafer is polished, the warpage and curvature of the wafer obtained without bonding the sacrificial component 20 cannot meet the actual use requirements.

[0075] It is understandable that the negative sign of the curvature only indicates the direction. By setting the sacrificial component 20, this application can effectively suppress the overall unidirectional bending of the wafer and significantly eliminate irregular warping and line defects at the entry point, so as to achieve the core technical objective of improving the wafer head morphology and enhancing product processing accuracy.

[0076] Comparing the data from Examples 1-6 and Comparative Example 2 reveals that: the hardness difference between the resin sacrificial block and the crystal rod 10 is significant. When the cutting wire mesh cuts into the resin sacrificial block, the cutting resistance is extremely low, and the cutting wire mesh is in a relaxed cutting state. The spiral will freely deviate due to the insufficient resistance, failing to form a stable cutting trajectory. At the instant the cutting wire mesh cuts into the crystal rod 10 from the resin assembly, the cutting resistance jumps sharply, creating a sudden increase in resistance. This sudden change generates a strong lateral impact force on the cutting wire mesh, causing the originally freely deviating spiral to fail to smoothly return to its correct position. Instead, it cuts into the crystal rod 10 with its deviated inertia, failing to effectively solve the warping problem.

[0077] Comparing the data from Examples 1, 4, 5, and 6, it can be seen that when the adhesive layer is between 2μm and 10μm, the adhesive layer can completely fill the micro gaps while maintaining high rigidity, and has the best rigidity matching with the sacrificial component 20 and the crystal rod 10.

[0078] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A method for cutting silicon carbide crystal rods, characterized in that, include: S100. Provide a crystal rod to be cut, the crystal rod having an arc-shaped outer peripheral surface extending along the axial direction; S200. Determine the entry vertex of the crystal rod in the cutting direction, and attach a sacrificial component at the entry vertex. The sacrificial component covers the entry vertex and extends along the axial direction of the crystal rod, and the adhesive forms a rigid adhesive layer. S300. Control the cutting wire mesh to feed in a direction perpendicular to the crystal rod axis, so that the cutting wire mesh first cuts into the sacrificial component and then into the crystal rod. The material of the sacrificial component is the same as that of the crystal rod, or the absolute value of the deviation between the Vickers hardness of the sacrificial component and the Vickers hardness of the crystal rod is less than a preset threshold, so that the cutting wire mesh maintains the continuity of cutting stress when it cuts into the crystal rod from the sacrificial component. In step S300, the preset threshold is 200 HV; The thickness of the adhesive layer is controlled between 2μm and 10μm, and the Shore hardness D of the adhesive layer is greater than 80.

2. The cutting method as described in claim 1, characterized in that, The thickness H of the sacrificial component along the cutting direction satisfies: 3mm≤H≤10mm.

3. The cutting method as described in any one of claims 1-2, characterized in that, The sacrificial assembly includes a plurality of sacrificial blocks arranged along the circumference of the crystal rod, wherein the sacrificial block located in the middle covers the cutting edge, and the sacrificial blocks located on both sides are inclined relative to the sacrificial block located in the middle, such that the bottom surfaces of the plurality of sacrificial blocks together fit the arc-shaped outer circumferential surface of the crystal rod.

4. The cutting method as described in claim 3, characterized in that, The sacrificial block is made from silicon carbide waste and has a rectangular cross-section perpendicular to the crystal rod axis.

5. The cutting method as described in claim 4, characterized in that, There is a gap between two adjacent sacrificial blocks, the width of which is 0.5mm to 4mm, and the circumferential length of each sacrificial block is 5mm to 30mm.

6. The cutting method as described in claim 5, characterized in that, The number of sacrificial blocks is 3. The middle sacrificial block is set horizontally, and the tilt angle α of the two sacrificial blocks relative to the middle sacrificial block satisfies: 10°≤α≤20°.

7. The cutting method as described in any one of claims 1-2, characterized in that, The sacrificial component is an integral arc-shaped block formed by sintering silicon carbide powder in a mold. The side of the arc-shaped block facing the crystal rod has a concave arc surface. The radius of curvature of the concave arc surface is equal to the radius of curvature of the arc-shaped outer circumference of the crystal rod to achieve a gapless fit.

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