Intelligent microjet water guide laser cutting system and cutting method of silicon carbide crystal bar

Abstract

The application discloses a kind of intelligent microfluid water guide laser cutting system and the cutting method of silicon carbide crystal bar, belong to silicon carbide crystal bar processing technical field.The cutting system includes: fixed mechanism, beam coupler, image capture mechanism, image processing mechanism and judging mechanism, and fixed mechanism is used to fix the piece to be cut;Beam coupler cuts the piece to be cut;Image capture mechanism is used to obtain the cutting path at cutting site;Image processing mechanism obtains the height difference information of cutting site by data conversion to image;Judging mechanism judges whether higher than threshold according to height difference information, if higher than threshold, then beam coupler cuts the piece to be cut in reverse direction.The cutting system judges whether there is cutting place long crystal defect by the height difference of cutting path obtained in real time, when there is long crystal defect, height difference is higher than threshold, at this time, reverse cutting is carried out to remove defect rapidly, cooperates and improves cutting efficiency and cutting quality, and reduces processing difficulty.

Description

Technical Field

[0001] This application relates to an intelligent micro-jet water-guided laser cutting system and a cutting method for silicon carbide crystal rods, belonging to the field of silicon carbide crystal rod processing technology. Background Technology

[0002] Silicon carbide (SiC) is a high-performance semiconductor material widely used in high-power, high-frequency, and high-temperature electronic devices. With the development of SiC technology, its applications in power electronics, optoelectronic devices, and high-temperature devices are constantly expanding, placing higher demands on the quality and processing technology of SiC crystal rods. However, current SiC crystal rod processing methods have many shortcomings, restricting the improvement of production efficiency and product quality. Microfluidic laser processing can improve processing efficiency and accuracy, and is gradually becoming a research hotspot for SiC crystal rods.

[0003] However, the processing efficiency of microfluidic lasers is significantly affected when encountering crystal growth defects such as microtubes, inclusions, and polycrystalline structures in silicon carbide ingots. Therefore, if these crystal growth defects are encountered during the processing of silicon carbide ingots, the cutting efficiency in some areas is likely to decrease significantly, thus significantly affecting the processing efficiency of silicon carbide ingots.

[0004] The applicant discovered that during microfluidic laser cutting, especially in ring-shaped processes, residual water in the kerf affects the stability of the laser beam as the cutting depth increases. When the cutting speed slows down in areas due to crystal growth defects, water accumulates in these areas, creating a "negative feedback" effect—that is, the slower-cutting areas become even slower. This "negative feedback" effect not only reduces overall processing efficiency but also leads to a decrease in cutting quality, increasing the complexity and difficulty of the process. Summary of the Invention

[0005] To address the aforementioned issues, an intelligent micro-fluidic laser cutting system and a silicon carbide crystal rod cutting method are provided. This cutting system determines the presence of crystal growth defects at the cutting point by real-time acquisition of the height difference of the cutting path. When crystal growth defects are present, the height difference exceeds a threshold, and reverse cutting is performed to quickly remove the defects, thereby synergistically improving cutting efficiency and quality while reducing processing difficulty.

[0006] According to one aspect of this application, an intelligent micro-jet water-guided laser cutting system is provided, comprising:

[0007] The fixing mechanism is used to fix the workpiece to be cut;

[0008] A beam coupler, comprising, from top to bottom, a laser emitter, a protective window, a water inlet, a nozzle, and an air inlet, is used to emit a micro-jets of water-guided laser, water, and protective gas to cut the workpiece.

[0009] An image capture mechanism, used to acquire the cutting path at the cutting location;

[0010] An image processing mechanism is used to receive the cutting path image captured by the image capture mechanism and perform data conversion on the image to obtain the height difference information of the cutting part;

[0011] The judging mechanism determines whether the height difference is higher than a threshold based on the height difference information. If it is not higher than the threshold, the beam coupler continues to cut the workpiece in the original direction. If it is higher than the threshold, the beam coupler cuts the workpiece in the reverse direction.

[0012] Optionally, the image capture mechanism includes a camera that acquires the cutting path of the cutting part by capturing the movement of the end point of the microjet water-guided laser.

[0013] Optionally, it also includes an XRD orientation mechanism;

[0014] The XRD orientation mechanism includes an X-ray emitting unit, an X-ray receiving unit, and a signal strength monitoring unit.

[0015] Optionally, the nozzle inner diameter of the beam coupler is 50–120 μm.

[0016] According to another aspect of this application, a method for cutting silicon carbide crystal rods is provided, which uses the cutting system described in any of the above claims to cut the silicon carbide crystal rods, comprising the following steps:

[0017] (1) A fixing mechanism is used to fix the silicon carbide crystal rod, and the silicon carbide crystal rod is cut along the first direction by a beam coupler;

[0018] (2) During the cutting process, the image capture mechanism acquires the cutting path of the cutting part in real time. The image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. The judgment mechanism judges whether the height difference within the 10mm cutting range is higher than the first threshold. If it is not higher than the first threshold, the beam coupler continues to cut the workpiece in the original direction until it is higher than the first threshold. Then, the beam coupler cuts the workpiece in the second direction, which is opposite to the first direction.

[0019] (3) The image capture mechanism continues to acquire the cutting path in real time, the image processing mechanism performs data conversion on the image to obtain the height difference information, and the judgment mechanism judges whether the height difference within the 10mm cutting range is higher than the second threshold. If it is not higher than the second threshold, the beam coupler continues to cut the workpiece in the original direction until it is higher than the second threshold. Then the beam coupler cuts the workpiece again along the first direction.

[0020] (4) Repeat steps (2) and (3) until the silicon carbide ingot is cut.

[0021] Based on this cutting system, the cutting method of this application, when using micro-jet water-guided laser for simultaneous rounding and positioning edge processing, can obtain the height difference at the cutting location based on the image capture mechanism and the image processing mechanism, and determine whether there is a crystal growth defect at the cutting location based on the height difference within a 10mm range. If the height difference exceeds the first threshold or the second threshold, reverse cutting is performed. This cutting method utilizes the influence of the height difference before and after cutting at the defect location on water accumulation to quickly remove the defect, so that the height at the cutting seam becomes uniform again, improving cutting efficiency and cutting quality while reducing processing difficulty.

[0022] The aforementioned height difference refers to the difference between the highest and lowest points within a 10mm cutting range. This method can eliminate the influence of crystal rod defects during the micro-jet laser rounding process, reduce the height difference of the cutting seam, and achieve uniform height at the cutting seam again. This reduces the impact of height difference on water accumulation, eliminates the "negative feedback" effect, significantly improves cutting efficiency, saves processing time, and increases production capacity.

[0023] Optionally, the value range of the first threshold is 300-500μm, and the value range of the second threshold is 300-500μm;

[0024] Preferably, the first threshold and the second threshold have the same value.

[0025] The range of values ​​for the first and second thresholds also affects the cutting efficiency. If the first and second thresholds are set too small, steps (2) and (3) will be repeated frequently during the cutting process, resulting in an increase in the number of times the laser stops and turns, thus increasing the overall cutting processing time. If the first and second thresholds are set too large, the laser will not be able to turn and cut in time when the "negative feedback" effect is generated, and there will still be areas with slow cutting speed. Furthermore, the time to eliminate the height difference after turning and cutting will also increase, thereby reducing the cutting efficiency and the quality after cutting.

[0026] Optionally, after the silicon carbide crystal rod is fixed, the cutting method further includes using an XRD orientation mechanism to orient the (0004) crystal plane or (11-28) crystal plane of the silicon carbide crystal rod, and after the orientation is completed, the silicon carbide crystal rod is cut along the first direction by a beam coupler.

[0027] After the orientation operation is completed, the cutting method integrates orientation and micro-jet water-guided laser processing. The positioning edge processing and rounding processing can be completed with a single setup, avoiding the offset of the crystal rod during processing, eliminating multiple adjustments and repetitive operations, and significantly improving production efficiency. At the same time, the boundary of the positioning edge is clear and there are no breaks or interfaces. The surface of the rounded crystal rod has high consistency, and the surface quality of the silicon carbide crystal rods obtained in mass production has high consistency.

[0028] Optionally, the positioning edge processing refers to being performed on the (1-100) crystal plane of the silicon carbide crystal rod.

[0029] Optionally, the specific method for orienting the (0004) or (11-28) crystal plane of the silicon carbide crystal rod using XRD is as follows:

[0030] First, adjust the incident angle θ1 and the exit angle θ2 of the X-rays, then rotate the silicon carbide crystal rod around the vertical centerline and perform... Scan until the position of maximum diffraction intensity is reached. Then rotate the silicon carbide crystal rod around the horizontal center line and perform χ scan until the position of maximum diffraction intensity is reached. Finally, continue to rotate the silicon carbide crystal rod around the horizontal center line and adjust the χ value according to the required crystal rod deflection angle.

[0031] Preferably, the rotation angle of the silicon carbide crystal rod about the horizontal center line is -10° to 10°.

[0032] The above orientation involves rotating the silicon carbide crystal rod around its vertical centerline and performing... The operation of scanning until the position of maximum diffraction intensity is to adjust the silicon carbide crystal rod to an initial horizontal position. Then, the silicon carbide crystal rod is rotated around the horizontal center line and χ scan is performed until the position of maximum diffraction intensity is reached. This operation is to adjust the upper surface of the silicon carbide crystal rod to the initial reference plane. At this time, the crystal rod deflection angle is 0°. Then, the rotation around the horizontal center line is continued to adjust the χ value, which is also the crystal rod deflection angle adjustment, until the desired deflection angle is achieved.

[0033] Optionally, when oriented the (0004) surface of the crystal rod, the incident angle θ1 and the exit angle θ2 of the X-rays are both 17.85°±0.1°.

[0034] Optionally, when using the (0004) crystal plane orientation, the process includes the following steps between rotating to the position where the diffraction intensity reaches its maximum and finally continuing to rotate the silicon carbide crystal rod around the horizontal centerline:

[0035] Stop rotating about the horizontal centerline. Then rotate the silicon carbide crystal rod 90° or 270° about the vertical centerline. Continue rotating about the horizontal centerline and perform χ scans until the position of maximum diffraction intensity is reached.

[0036] Because the crystal surface after growth has orthogonal orientation deviation, rotating the silicon carbide crystal rod around the horizontal center line and performing χ scans until the position with the maximum diffraction intensity is obtained is not the true position of the strongest signal. Therefore, rotating the silicon carbide crystal rod around the vertical center line by 90° or 270° and then rotating it around the horizontal center line and performing χ scans can correct the error of the previous χ scans, thus obtaining the true position of the strongest signal.

[0037] Optionally, when orienting the (11-28) plane of the crystal rod, the incident angle θ1 and the exit angle θ2 of the X-rays are adjusted to 9°±0.1° and 96°±0.1°, respectively.

[0038] Optionally, the required crystal rod deflection angle can range from 1° to 8°. For example, it can be 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, or any angle in between.

[0039] Optionally, the relative cutting speed of the micro-jet water-guided laser is 100–800 mm / min.

[0040] Optionally, the power of the microjet water-guided laser is 40–200W, and the frequency is 6–10KHz.

[0041] The power and frequency of this micro-jets water-guided laser directly affect its ability to cut silicon carbide ingots, thus impacting the rounding cutting efficiency and quality. Insufficient power and frequency lead to decreased cutting efficiency, hindering large-scale production; excessive power and frequency, while increasing cutting efficiency, can cause edge chipping or ingot cracking during rounding, reducing product yield.

[0042] Optionally, the gas pressure of the beam coupler is 0.2 to 1 L / min, and the water pressure is 200 to 500 bar.

[0043] Optionally, the water is ultrapure water, and the gas is nitrogen or helium.

[0044] Water pressure is related to the effective cutting length of the microfluidic laser. This water pressure should be matched with the power of the microfluidic laser to improve cutting efficiency, surface quality of the cut crystal rod, and yield. Higher water pressure results in a longer effective cutting length and higher cutting efficiency, but excessive water pressure can also damage the silicon carbide crystal rod, reducing its surface quality and yield.

[0045] Increased gas pressure can increase processing efficiency; however, excessive gas pressure can lead to gas waste and deteriorate the surface quality of the crystal rod.

[0046] Optionally, the water pressure is P1, in bar, and the gas pressure is P2, in L / min. P1 and P2 satisfy the following relationship:

[0047] P1 / 1000≤P2≤P1 / 500.

[0048] By using coaxial protective gas to surround the water jet and adjusting the water-gas interface by controlling the gas flow rate, interference from the surrounding atmosphere can be reduced and the coherence length of the water jet can be increased.

[0049] The beneficial effects of this application include, but are not limited to:

[0050] 1. The intelligent micro-jet water-guided laser cutting system of this application provides real-time feedback of cutting path and height difference information through an image capture mechanism and an image processing mechanism. It also determines whether there are crystal growth defects by comparing the height difference information with a preset threshold, thereby controlling the beam coupler to reverse the cutting to quickly remove defects, improving cutting efficiency and cutting quality while reducing processing difficulty.

[0051] 2. The intelligent micro-jet water-guided laser cutting system of this application is particularly suitable for silicon carbide crystal rods that have stress defects. Traditional mechanical grinding methods are prone to causing new defects when processing such crystal rods. The processing method of this application solves the "negative feedback" effect caused by defects in such crystal rods without introducing new defects, thus significantly improving processing quality and product yield.

[0052] 3. According to the silicon carbide crystal rod cutting method of this application, the height difference fed back by the image capture mechanism and the image processing mechanism determines whether to perform reverse cutting based on the set threshold. This can smoothly re-uniform the cutting height difference formed by the crystal growth defect area, solve the "negative feedback" effect caused by crystal growth defects during the micro-jets laser rounding process, and synergistically improve the processing efficiency of the crystal rod and the surface quality of the processed crystal rod, reduce the complexity and difficulty of processing, and facilitate industrial promotion and use.

[0053] 4. The silicon carbide crystal rod cutting method of this application, with the processing parameters of the micro-jets water-guided laser working together, causes less damage to the crystal rod, reduces the generation of defects such as cracks and edge chipping, reduces the amount of silicon carbide debris and material loss, reduces production costs and environmental impact; improves the yield and processing efficiency of silicon carbide crystal rods, and the outer periphery of the processed silicon carbide crystal rods is uniform and the surface quality is high.

[0054] 5. The silicon carbide crystal rod cutting system and cutting method of this application can realize efficient and precise rounding and positioning edge processing of silicon carbide crystal rods. Compared with the existing mechanical grinding processing of silicon carbide crystal rods, it has obvious advantages in quality, efficiency and economy, and has broad application prospects and important practical significance. Attached Figure Description

[0055] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0056] Figure 1 This is a schematic diagram of the intelligent micro-jet water-guided laser cutting system involved in Embodiment 1 of this application.

[0057] Figure 2 This is an operational logic diagram of the intelligent micro-jet water-guided laser cutting system involved in Embodiment 1 of this application;

[0058] Figure 3 This is a side cross-sectional schematic diagram of the beam coupler involved in the embodiments of this application.

[0059] Figure 4 This is a schematic diagram of the cutting involved in Embodiment 1 and Comparative Example 1 of this application.

[0060] List of components and reference numerals:

[0061] 1. Base; 2. X-ray emitting unit; 3. X-ray receiving unit; 4. Beam coupler; 41. Laser emitting unit; 42. Protective window; 43. Water inlet; 44. Nozzle; 45. Air inlet; 46. Micro-jet water-guided laser; 5. Workpiece to be cut; 6. Image capture mechanism; 7. Image processing mechanism; 8. Judgment mechanism. Detailed Implementation

[0062] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0063] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0064] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0065] Example 1

[0066] refer to Figure 1-3This embodiment relates to an intelligent micro-jet water-guided laser 46 cutting system, including a fixing mechanism, a beam coupler 4, an image capture mechanism 6, an image processing mechanism 7, and a judgment mechanism 8. The fixing mechanism is used to fix the workpiece 5 to be cut; the beam coupler 4 includes, from top to bottom, a laser emitting part 41, a protective window 42, a water inlet 43, a nozzle 44, and an air inlet 45. The beam coupler 4 is used to emit micro-jet water-guided laser 46, water, and protective gas to cut the workpiece 5; the image capture mechanism 6 is used to acquire the cutting path of the cutting part; the image processing mechanism 7 is used to receive the cutting path image captured by the image capture mechanism 6 and perform data conversion on the image to obtain the height difference information of the cutting part; the judgment mechanism 8 determines whether the height difference is higher than a threshold based on the height difference information. If it is not higher than the threshold, the beam coupler 4 continues to cut the workpiece 5 in the original direction; if it is higher than the threshold, the beam coupler 4 cuts the workpiece 5 in the reverse direction.

[0067] This cutting system uses an image capture mechanism 6 to acquire the cutting path of the laser at the cutting location in real time, and an image processing mechanism 7 to convert the cutting path image into height difference information. This height difference information is transmitted to a judgment mechanism 8 for judgment. The judgment mechanism 8 determines whether the height difference is higher than a threshold to determine the cutting direction of the laser. If it is higher than the threshold, it indicates the presence of a crystal growth defect. By reverse cutting, the system utilizes the effect of the height difference before and after cutting on water accumulation at the defect to quickly remove the defect and make the height at the cut seam uniform again. If the height difference is higher than the threshold again, it indicates the recurrence of a crystal growth defect. Reverse cutting can be performed again to remove the defect and achieve uniform height at the cut seam again. This cutting system can improve cutting efficiency while improving cutting quality and reducing processing difficulty.

[0068] In one implementation, the image capture mechanism 6 includes a camera that acquires the cutting path of the cutting area by capturing the movement of the end point of the micro-jet water-guided laser 46. The end point of the micro-jet water-guided laser 46 is the deepest point cut by the micro-jet water-guided laser 46, and the movement path of this deepest point is the cutting path of the cutting area. By capturing the movement of the laser's end point through the camera, the cutting path can be directly reflected. At this time, the image processing mechanism 7 compares the position of the laser's end point in the image captured by the camera and obtains the height difference at the cutting area by addition and subtraction, so that the judgment mechanism 8 can make a judgment and decide whether to change the cutting direction.

[0069] This setting improves the efficiency and accuracy of the cutting system in capturing the cutting path and calculating the height difference, ensuring smooth operation. It also allows for the statistical analysis of the cutting path and height difference throughout the entire cutting process, providing operators with data for ingot quality feedback and serving as a basis for adjusting the parameters of the micro-jets water-guided laser 46.

[0070] Those skilled in the art will understand that the image capture mechanism 6 is not limited to a camera, and may also employ other existing technologies capable of capturing the movement of the end point of the micro-jet water-guided laser 46, such as using a laser tracker or other tracking methods.

[0071] The processing of silicon carbide crystal rods also includes the processing of the positioning edges, which directly affects the quality of the crystal rods leaving the factory. If there is a deviation in the positioning edges, it will lead to a significant decrease in the production quality of the epitaxial wafers. Before processing the positioning edges, the silicon carbide crystal rods also need to be oriented.

[0072] In one embodiment, the cutting system also includes an XRD orientation mechanism, which includes an X-ray emitting unit 2, an X-ray receiving unit 3, and a signal intensity monitoring unit.

[0073] X-ray emitting unit 2 emits X-ray incident rays, X-ray receiving unit 3 receives X-ray reflected rays, and signal intensity monitoring unit detects the signal intensity of the reflected rays. Based on the received signal intensity, it determines whether the orientation is complete. With the addition of an XRD orientation mechanism, this cutting system can orient the silicon carbide ingot using XRD before cutting, followed by processing with the micro-jets of the water-guided laser 46. This allows for integrated processing of the silicon carbide ingot's orientation, rounding, and positioning edges, or it can be used alone to round or position the edges, thus expanding the system's application range.

[0074] In addition, the XRD orientation mechanism can detect the orientation accuracy in real time during the processing, achieving the effect of instant processing and instant feedback, thereby ensuring the smooth processing of rounding and positioning edges.

[0075] In one implementation, the fixing mechanism is a base 1, and the part to be cut 5 is fixed on the base 1 by adhesive or vacuum adsorption.

[0076] In one embodiment, the cutting system further includes a first driving mechanism and a second driving mechanism. The first driving mechanism is used to drive the workpiece 5 to be cut to rotate about a vertical center line and about a horizontal center line, and the second driving mechanism is used to drive the beam coupler 4 to move relative to the workpiece 5.

[0077] Since the XRD orientation mechanism is required for orientation before the positioning edge is processed, the workpiece 5 to be cut needs to be rotated sequentially around the vertical center line and around the horizontal center line during the orientation process. Therefore, the first drive mechanism can make the orientation process go smoothly. During the rounding and positioning edge cutting process, the workpiece 5 to be cut and the beam coupler 4 need to move relative to each other to achieve cutting. Therefore, the second drive mechanism drives the beam coupler 4 to move, thereby making the cutting process go smoothly.

[0078] The structure and operation of the first and second drive mechanisms can refer to existing technologies. For example, the first drive mechanism may include a rotating shaft and two lifting columns. The bottom of the rotating shaft is fixedly connected to a rotary motor through the operating table, and the top of the rotating shaft is fixedly connected to the center of the base 1. The rotating motor drives the base 1 to rotate, thereby achieving the rotation of the workpiece 5 to be cut around the vertical center line. The two lifting columns are symmetrically distributed on both sides of the rotating shaft. The bottom of the lifting columns is fixedly set on the operating table, and the top can abut against the bottom surface of the base 1 but is not directly connected. By adjusting the lifting height of the two lifting columns, the tilting rotation of the workpiece 5 to be cut, that is, the rotation around the horizontal center line, can be achieved. The lifting of the two lifting columns can be achieved by two lifting motors respectively. For example, the second drive mechanism can be in the form of an electromagnetic drive, which realizes the movement of the beam coupler 4 along the cutting path through the electromagnetic driver. The second drive mechanism can also be realized by a first drive plate, a second drive plate and a third drive plate connected from top to bottom. The bottom surface of the third drive plate is connected to the beam coupler 4, and the beam coupler 4 can move in a circle along the third drive plate. The bottom surface of the second drive plate is connected to the top surface of the third drive plate, and the third drive plate can move left and right along the second drive plate. The bottom surface of the first drive plate is connected to the top surface of the second drive plate, and the second drive plate can move back and forth along the first drive plate. Therefore, through the cooperation of the first drive plate, the second drive plate and the third drive plate, the beam coupler 4 can realize the rotation and horizontal movement of the workpiece 5 to be cut. The movement path can be set according to actual needs, thereby realizing the integrated processing of rounding and positioning edges.

[0079] In one embodiment, the nozzle 44 of the beam coupler 4 has an inner diameter of 50–120 μm.

[0080] The following Examples 2-14 and Comparative Examples all use the cutting system of Example 1 to cut silicon carbide crystal rods. Therefore, the specific components of the above cutting system will not be labeled in the following Examples 2-14 and Comparative Examples.

[0081] Example 2

[0082] This embodiment relates to a method for processing silicon carbide crystal rods, including the following steps:

[0083] (1) Fix the silicon carbide crystal rod on the base, and use an XRD orientation mechanism to orient the (11-28) crystal plane of the silicon carbide crystal rod. First, adjust the incident angle θ1 and the exit angle θ2 of the X-rays to 9°±0.1° and 96°±0.1° respectively through the X-ray emitting unit and the X-ray receiving unit. Then, rotate the silicon carbide crystal rod around the vertical center line as the axis and perform... Scanning, signal strength monitoring unit detects in real time The silicon carbide crystal rod is rotated around the horizontal center line and χ scan is performed. The rotation angle is -10° to 10°. The signal intensity monitoring unit detects the χ value in real time until the position of the maximum diffraction intensity is reached and marked as the point of the strongest signal 2. Finally, the silicon carbide crystal rod is rotated around the horizontal center line and the χ value is adjusted according to the crystal rod deflection angle of 1°.

[0084] (2)Reference Figure 4 In section (A), a micro-jet water-guided laser is used to round a silicon carbide crystal rod in the forward direction (along the first direction) and to perform Notch-type positioning edge cutting on the (1-100) crystal plane of the crystal rod. During the cutting process, an image capture mechanism acquires the cutting path of the cutting part in real time, and an image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. Figure 4 (B) represents the cut kerf produced during normal cutting, with a relatively uniform height. When the cutting process passes through... Figure 4 When the silicon carbide crystal exhibits a growth defect at point (C), a height difference will appear in the cutting kerf. The judgment mechanism determines whether the height difference exceeds 500μm within a 10mm cutting range. If it does not exceed 500μm, the beam coupler continues to cut the silicon carbide crystal in its original direction until it exceeds 500μm. (Refer to...) Figure 4 In the middle (D2), the beam coupler performs rounding and positioning edge cutting on the silicon carbide ingot in the reverse direction (along the second direction). Figure 4 As can be seen from E2, this reverse cutting can utilize the effect of the height difference before and after cutting on the water accumulation at the defect to quickly remove the defect and make the height at the cut seam uniform again.

[0085] (3) During the reverse cutting process, the image capture mechanism continues to acquire the cutting path of the cutting part in real time. The image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. The judgment mechanism judges whether the height difference within the 10mm cutting range is higher than 500μm. If it is not higher than 500μm, the beam coupler continues to cut the silicon carbide crystal rod in the original direction until it is higher than 500μm. Then, the beam coupler re-rounds and positions the silicon carbide crystal rod in the first direction (along the first direction).

[0086] (4) Repeat steps (2) and (3) until the silicon carbide ingot is rounded and the positioning edge is cut. Refer to Figure 4 In the middle (F), the silicon carbide ingot can be cut through in height at the same time during the cutting process.

[0087] In steps (2) and (3), the micro-jets water-guided laser is emitted through a beam coupler. The gas pressure of the beam coupler is 0.2 L / min, the water pressure is 200 bar, the nozzle inner diameter is 120 μm, the relative cutting speed of the micro-jets water-guided laser is 100 mm / min, the power is 200 W, and the frequency is 10 kHz.

[0088] Example 3

[0089] This embodiment relates to a method for processing silicon carbide crystal rods, including the following steps:

[0090] (1) Fix the silicon carbide crystal rod on the base, and use an XRD orientation mechanism to orient the (0004) crystal plane of the silicon carbide crystal rod. First, adjust the incident angle θ1 and the exit angle θ2 of the X-rays to 17.85°±0.1° using the X-ray emitting unit and the X-ray receiving unit. Then, rotate the silicon carbide crystal rod around the vertical center line as the axis and perform... Scanning, signal strength monitoring unit detects in real time The silicon carbide crystal rod is rotated around the horizontal center line and subjected to χ² scans at an angle of -10° to 10°. The signal intensity monitoring unit detects the χ² value in real time until the position of maximum diffraction intensity is reached, which is marked as the point of maximum signal strength 2. The silicon carbide crystal rod is then rotated 90° or 270° around the vertical center line and rotated around the horizontal center line while performing χ² scans until the position of maximum diffraction intensity is reached, which is marked as the point of maximum signal strength 3. Finally, the silicon carbide crystal rod is rotated around the horizontal center line and the χ² value is adjusted according to the crystal rod's deflection angle of 8°.

[0091] (2)Reference Figure 4 In section (A), a micro-jet water-guided laser is used to round a silicon carbide crystal rod in the forward direction (along the first direction) and to perform Notch-type positioning edge cutting on the (1-100) crystal plane of the crystal rod. During the cutting process, an image capture mechanism acquires the cutting path of the cutting part in real time, and an image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. Figure 4 (B) represents the cut kerf produced during normal cutting, with a relatively uniform height. When the cutting process passes through... Figure 4 When the silicon carbide crystal exhibits a growth defect at point (C), a height difference will appear in the cutting kerf. The judgment mechanism determines whether the height difference exceeds 300μm within a 10mm cutting range. If it does not exceed 300μm, the beam coupler continues to cut the silicon carbide crystal in its original direction until it exceeds 300μm. (Refer to...) Figure 4 In the middle (D2), the beam coupler performs rounding and positioning edge cutting on the silicon carbide ingot in the reverse direction (along the second direction). Figure 4As can be seen from E2, this reverse cutting can utilize the effect of the height difference before and after cutting on the water accumulation at the defect to quickly remove the defect and make the height at the cut seam uniform again.

[0092] (3) During the reverse cutting process, the image capture mechanism continues to acquire the cutting path of the cutting part in real time. The image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. The judgment mechanism judges whether the height difference within the 10mm cutting range is higher than 300μm. If it is not higher than 300μm, the beam coupler continues to cut the silicon carbide crystal rod in the original direction until it is higher than 300μm. Then, the beam coupler re-rounds and positions the silicon carbide crystal rod in the first direction.

[0093] (4) Repeat steps (2) and (3) until the silicon carbide ingot is rounded and the positioning edge is cut. Refer to Figure 4 In the middle (F), the silicon carbide ingot can be cut through in height at the same time during the cutting process.

[0094] In steps (2) and (3), the micro-jets water-guided laser is emitted through a beam coupler. The gas pressure of the beam coupler is 1L / min, the water pressure is 500bar, the nozzle inner diameter is 50μm, the relative cutting speed of the micro-jets water-guided laser is 800mm / min, the power is 40W, and the frequency is 6KHz.

[0095] Example 4

[0096] The difference between this embodiment and Embodiment 2 is that the nozzle inner diameter of the beam coupler is 80μm, the water pressure is 400bar, the gas pressure is 0.4L / min, the power of the microjets water-guided laser is 160W, the frequency is 8KHz, and the relative cutting speed is 400mm / min.

[0097] Example 5

[0098] The difference between this embodiment and embodiment 4 is that the power of the micro-jet water-guided laser is 220W, while the rest is the same as in embodiment 4.

[0099] Example 6

[0100] The difference between this embodiment and embodiment 4 is that the frequency of the micro-jet water-guided laser is 12kHz, while the rest is the same as in embodiment 4.

[0101] Example 7

[0102] The difference between this embodiment and embodiment 4 is that the water pressure is 200 bar, otherwise it is the same as embodiment 4.

[0103] Example 8

[0104] The difference between this embodiment and embodiment 4 is that the water pressure is 550 bar, otherwise it is the same as embodiment 4.

[0105] Example 9

[0106] The difference between this embodiment and embodiment 4 is that the gas pressure is 0.1 L / min, while the rest is the same as in embodiment 4.

[0107] Example 10

[0108] The difference between this embodiment and embodiment 4 is that the gas pressure is 1.2 L / min, while the rest is the same as in embodiment 4.

[0109] Example 11

[0110] The difference between this embodiment and embodiment 4 is that the relative cutting speed of the micro-jet water-guided laser is 80 mm / min, while the rest is the same as in embodiment 4.

[0111] Example 12

[0112] The difference between this embodiment and embodiment 4 is that the relative cutting speed of the micro-jet water-guided laser is 1000 mm / min, while the rest is the same as in embodiment 4.

[0113] Example 13

[0114] The difference between this embodiment and embodiment 4 is that in step (1), reverse cutting is only performed when the height difference between the ends of the micro-jet water-guided laser within a range of 10 mm is greater than 600 μm. In step (2), step (1) is repeated only when the height difference between the ends of the micro-jet water-guided laser within a range of 10 mm is greater than 600 μm. The rest is the same as in embodiment 4.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 4 is that, with reference to Figure 4 During the cutting process Figure 4 When there is a height difference in the cutting kerf at the long crystal defect in (C), the forward cyclic cutting continues throughout the entire rounding cutting process. Figure 4 As can be seen in (D1), the forward cyclic cutting causes water to accumulate in the area due to the height difference before and after cutting, thus making the cutting process even slower in areas that were already slow. (See reference...) Figure 4 In the middle (E1) region, even when other areas are cut through, the crystal growth defect area still has a high uncut peak, requiring a significant amount of cutting time to achieve the desired result. Figure 4 The effect of complete cutting through (F) is shown. The cutting parameters of the micro-jet water-guided laser in Comparative Example 1 are the same as those in Example 4.

[0117] Comparative Example 2

[0118] The comparative example follows the same steps as in Example 4 (1). Steps (2)-(4) involve mechanical grinding to round and position the silicon carbide edges. The rounding parameters are: 200-grit grinding wheel, 1000 rpm / min rotation speed, 300 rpm / min workpiece rotation speed, 200 mm / min left and right movement speed, and 15 μm / pass feed. The positioning parameters are: 500-grit grinding wheel, 500 rpm / min rotation speed, 5 μm single pass feed, and 50 mm / min speed.

[0119] Test Example 1

[0120] Using the methods described in the above embodiments and comparative examples, silicon carbide ingots produced in the same batch were rounded and notched on the (1-100) crystal plane. The silicon carbide ingots had a diameter of 150 mm, a thickness of 20 mm, and a rounding cut width of 4 mm. Ten parallel experiments were conducted for each embodiment or comparative example to test processing time, surface roughness, maximum chipping size, and product yield. The test results are shown in Table 1. The product yield was calculated using the formula: (Total number of products - Number of defective products / Total number of products) × 100. Defective products were defined as those with chipping > 100 μm or exhibiting cracking.

[0121] Table 1

[0122]

[0123]

[0124] As shown in Table 1, with XRD positioning assistance, laser processing simultaneously machining the positioning edges during the rounding process can improve overall processing efficiency and yield. Specifically, the highest processing efficiency was achieved under the process conditions of Example 2, but the processing quality and yield were worse than those of Examples 3 and 4. Although the best processing quality was achieved in Example 3, processing efficiency was greatly sacrificed. The processing conditions of Example 4 balanced processing efficiency and processing quality, and Example 4 showed significant improvements in both efficiency and quality.

[0125] Increasing laser power enhances the direct effect, thereby accelerating processing efficiency. However, in Example 5, the increased laser power resulted in higher surface roughness, more severe edge chipping, and a lower yield. In Example 6, the increased frequency led to a larger laser spot, affecting cutting efficiency and slightly reducing processing quality.

[0126] In Example 7, the water pressure and gas flow rate meet steady-state conditions. However, a decrease in water pressure leads to a shorter effective cutting length, affecting processing efficiency and quality. In Examples 8-10, the mismatch between water pressure and gas pressure causes micro-injection instability, significantly impacting processing efficiency and surface quality. Therefore, the water-gas balance needs to be adjusted within the parameter range according to specific circumstances.

[0127] In Example 11, reducing the relative cutting speed increases the interaction time between the laser and the crystal rod, enhancing cutting capability, but leads to poorer surface quality and increased cutting speed. Example 12 shows the opposite. In Example 13, increasing the judgment threshold leads to decreased cutting efficiency, thereby extending processing time.

[0128] In Comparative Example 1, reverse cutting is not used. Under the same cutting process, the surface quality is not significantly affected, but the processing efficiency is drastically reduced. Overall, laser processing results in smaller chipping dimensions compared to the machining process in Comparative Example 2.

[0129] The above are merely embodiments of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. An intelligent micro-jet water-guided laser cutting system, characterized in that, include: The fixing mechanism is used to fix the workpiece to be cut; A beam coupler, comprising, from top to bottom, a laser emitter, a protective window, a water inlet, a nozzle, and an air inlet, is used to emit a micro-jets of water-guided laser, water, and protective gas to cut the workpiece. An image capture mechanism, used to acquire the cutting path at the cutting location; An image processing mechanism is used to receive the cutting path image captured by the image capture mechanism and perform data conversion on the image to obtain the height difference information of the cutting part; The judging mechanism determines whether the height difference is higher than a threshold based on the height difference information. If it is not higher than the threshold, the beam coupler continues to cut the workpiece in the original direction. If it is higher than the threshold, the beam coupler cuts the workpiece in the reverse direction.

2. The intelligent micro-jet water-guided laser cutting system according to claim 1, characterized in that, The image capture mechanism includes a camera, which acquires the cutting path of the cutting part by capturing the movement of the end point of the micro-jet water-guided laser.

3. The intelligent micro-jet water-guided laser cutting system according to claim 1, characterized in that, It also includes XRD orientation mechanisms; The XRD orientation mechanism includes an X-ray emitting unit, an X-ray receiving unit, and a signal strength monitoring unit.

4. The intelligent micro-jet water-guided laser cutting system according to claim 1, characterized in that, The inner diameter of the nozzle of the beam coupler is 50~120μm.

5. A method for cutting silicon carbide crystal rods, characterized in that, The method of cutting silicon carbide ingots using the cutting system described in any one of claims 1-4 includes the following steps: (1) The silicon carbide crystal rod is fixed by a fixing mechanism and the silicon carbide crystal rod is cut along the first direction by a beam coupler; (2) During the cutting process, the image capture mechanism acquires the cutting path of the cutting part in real time. The image processing mechanism receives the cutting path image captured by the image capture mechanism and performs data conversion on the image to obtain the height difference information of the cutting part. The judgment mechanism judges whether the height difference within the 10mm cutting range is higher than the first threshold. If it is not higher than the first threshold, the beam coupler continues to cut the workpiece in the original direction until it is higher than the first threshold. Then, the beam coupler cuts the workpiece in the second direction, which is opposite to the first direction. (3) The image capture mechanism continues to acquire the cutting path in real time, the image processing mechanism performs data conversion on the image to obtain the height difference information, and the judgment mechanism judges whether the height difference within the 10mm cutting range is higher than the second threshold. If it is not higher than the second threshold, the beam coupler continues to cut the workpiece in the original direction until it is higher than the second threshold. Then the beam coupler cuts the workpiece again along the first direction. (4) Repeat steps (2) and (3) until the silicon carbide ingot is cut.

6. The method according to claim 5, characterized in that, The first threshold value ranges from 300 to 500 μm, and the second threshold value ranges from 300 to 500 μm.

7. The method according to claim 6, characterized in that, The first threshold and the second threshold have the same value.

8. The method according to claim 5, characterized in that, The relative cutting speed of the micro-jet water-guided laser is 100~800 mm / min.

9. The method according to claim 5, characterized in that, The power of the micro-jets water-guided laser is 40~200W, and the frequency is 6~10KHz.

10. The method according to claim 5, characterized in that, The gas pressure of the beam coupler is 0.2~1L / min, and the water pressure is 200~500bar.

11. The method according to claim 10, characterized in that, The water pressure is P1, in bar, and the gas flow rate is P2, in L / min. P1 and P2 satisfy the following relationship: P1 / 1000≤P2≤P1 / 500.

Images