12-inch silicon carbide seed crystal based on water-guided laser and preparation method thereof

Abstract

The invention discloses a 12-inch silicon carbide seed crystal based on water-guided laser and a preparation method of the 12-inch silicon carbide seed crystal. The method comprises the following steps: obtaining five SiC wafers; fixing a first SiC wafer in the five SiC wafers on a vacuum chuck, and adjusting the vertical position of the first SiC wafer and the laser microjet; cutting the first SiC wafer by using laser microjet to obtain a first fan-shaped slice with a preset angle and radius; repeating the above steps on the other four SiC wafers to respectively obtain a second fan-shaped slice to a fifth fan-shaped slice with the same radius as the first fan-shaped slice; and splicing all the fan-shaped slices to obtain the 12-inch SiC seed crystal. According to the invention, the small-size SiC wafer is cut into the fan-shaped wafers by adopting the micro jet water guide laser cutting technology, and then the fan-shaped wafers are combined into the 12-inch seed crystal by adopting the splicing technology, the 12-inch seed crystal can be used for growing the 12-inch crystal ingot, and the large crystal ingot can reduce the cost of batch production and improve the overall production efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of shaped machining by water-jet guided laser, and particularly relates to a 12-inch silicon carbide seed crystal based on water-jet guided laser and a preparation method thereof. Background Art

[0002] Silicon carbide (SiC) is a wide-bandgap semiconductor material with characteristics such as high thermal conductivity, high breakdown electric field, and high saturated electron velocity. Therefore, it performs excellently in high-frequency, high-temperature, and high-pressure environments and can be used to manufacture high-performance power devices and radio frequency devices, which are widely used in fields such as electric vehicles, new energy, and 5G communication.

[0003] Currently, the mainstream sizes of silicon carbide (SiC) wafers are 6 inches (150 mm) and 8 inches (200 mm), and these sizes are widely used in power electronic devices (such as MOSFET, SBD, IGBT, etc.) and radio frequency electronic devices (such as GaN-on-SiC radio frequency devices). Specifically, 6 inches is the traditional size of SiC wafers, with mature processes and low costs, suitable for small and medium-scale applications; 8 inches has gradually become the market mainstream. Especially under the demand for high performance and large-scale production, the 8-inch wafers have a larger area, which can increase the chip yield and reduce costs. The 12-inch (300 mm) silicon carbide wafers are still in the research and development and small-scale test stage and have not become the market mainstream. The main technical difficulties lie in the problems of high cost, low efficiency, and size limitation in traditional preparation methods.

[0004] Currently, the preparation of 12-inch SiC (silicon carbide) seed crystals mainly relies on physical vapor transport method (PVT) and chemical vapor deposition method (CVD). However, these methods have the following problems: low utilization rate of raw materials, large equipment investment, long growth cycle, and it is difficult to meet the demand for large-scale production; it is difficult to directly prepare large-size seed crystals by traditional methods and they need to be indirectly realized by means such as splicing. Therefore, there is an urgent need to develop an efficient and economical preparation process. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a 12-inch silicon carbide seed crystal based on water-jet guided laser and a preparation method thereof, which can shorten the preparation cycle of the 12-inch silicon carbide seed crystal and reduce the production cost at the same time. The technical problems to be solved by the present invention are realized through the following technical solutions: The present invention provides a preparation method of a 12-inch silicon carbide seed crystal based on water-jet guided laser, including: S1: Obtain five SiC wafers with preset sizes; S2: Fix the first SiC wafer among the five SiC wafers on a vacuum chuck and adjust the perpendicularity of the laser microjet nozzle of the laser microjet processing equipment to the surface of the first SiC wafer, so that the laser microjet ejected from the laser microjet nozzle is perpendicular to the first SiC wafer during the cutting process; S3: Use the laser microjet to cut the first SiC wafer to obtain a first sector slice with a preset angle and radius; S4: Replace the first SiC wafer in steps S1 to S3 with the remaining four SiC wafers among the five SiC wafers respectively, and sequentially execute steps S1 to S3 to obtain a second sector slice, a third sector slice, a fourth sector slice, and a fifth sector slice that have the same radius as the first sector slice; S5: Splice the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice to obtain a 12-inch SiC seed crystal.

[0006] In an embodiment of the present invention, the S2 includes: S2.1: Fix the first SiC wafer to the vacuum chuck and adjust the horizontal position of the first SiC wafer according to the notch on the first SiC wafer; S2.2: Connect the vacuum chuck to a vacuum pump, turn on the vacuum pump, and control the vacuum pressure below -5 pa to adsorb the first SiC wafer to the surface of the vacuum chuck through negative pressure; S2.3: Adjust the perpendicularity of the laser microjet of the laser microjet processing equipment to the surface of the first SiC wafer, so that the laser microjet is perpendicular to the surface of the first SiC wafer, and set the cutting parameters.

[0007] In an embodiment of the present invention, the cutting parameters include the rated power of the laser of the laser microjet processing equipment, the wavelength of the laser, the pulse frequency of the laser, the nozzle diameter of the laser microjet processing equipment, and the water pressure.

[0008] In an embodiment of the present invention, adjusting the horizontal position of the first SiC wafer according to the notch on the first SiC wafer includes: Use the camera on the laser microjet processing equipment to adjust the position of the notch on the first SiC wafer, so that the center of the two-dimensional coordinate axis on the camera viewing surface coincides with the center of the SiC wafer, and the notch is symmetric about the Y axis of the two-dimensional coordinate axis.

[0009] In an embodiment of the present invention, the S3 includes: Set a first cutting path such that the first sector slice cut is centered on the Y-axis of the two-dimensional coordinate axis and has the first intersection point of the Y-axis and the first SiC wafer as the center of the circle, where the first intersection point is the intersection point of the Y-axis and the first SiC wafer far from the notch; According to the first cutting path, use the laser microjet to perform cutting to obtain the first sector slice.

[0010] In an embodiment of the present invention, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice have the same angle as the first sector slice, all being 72°.

[0011] In an embodiment of the present invention, in S4, the process of cutting the second SiC wafer to form the second sector slice includes: Fix the second SiC wafer on a vacuum chuck and adjust the vertical position of the second SiC wafer and the laser microjet, and ensure that the position of the notch on the second SiC wafer is the same as the position of the notch on the first SiC wafer; Set the second cutting path of the second SiC wafer such that the central axis of the second SiC wafer rotates counterclockwise by 72° relative to the Y-axis of the two-dimensional coordinate axis, and obtain a second sector slice with an angle of 72° according to the second cutting path.

[0012] In an embodiment of the present invention, during the cutting process, the central axis of the third cutting path of the third sector slice rotates counterclockwise by 144° relative to the Y-axis of the two-dimensional coordinate axis; the central axis of the fourth cutting path of the fourth sector slice rotates counterclockwise by 216° relative to the Y-axis of the two-dimensional coordinate axis; the central axis of the fifth cutting path of the fifth sector slice rotates counterclockwise by 288° relative to the Y-axis of the two-dimensional coordinate axis.

[0013] In an embodiment of the present invention, S5 includes: Bond the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice in sequence to obtain a bonded seed crystal; Polish the seed crystal to eliminate surface defects to obtain a 12-inch silicon carbide seed crystal for 12-inch silicon carbide ingot growth.

[0014] Another aspect of the present invention provides a 12-inch silicon carbide seed crystal based on water-guided laser, and the 12-inch silicon carbide seed crystal is prepared by using the preparation method described in any one of the above embodiments.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention provides a method for preparing a 12-inch silicon carbide seed crystal based on water-jet guided laser. By using a micro-jet laser processing device for wafer cutting, it can effectively reduce wafer chipping, obtain SiC seed crystals that can be directly used for splicing, reduce the back-end processing process, and improve production efficiency at the same time. The present invention adopts the micro-jet water-jet guided laser cutting technology to cut small-sized SiC wafers into fan-shaped wafers, and then combines them into 12-inch seed crystals through high-precision splicing technology. Cutting and splicing smaller wafers to obtain larger 12-inch seed crystals can improve material utilization rate, reduce waste, and lower production costs.

[0016] 2. The 12-inch silicon carbide seed crystal prepared by the preparation method of the present invention can be used to grow 12-inch silicon carbide ingots. Larger ingots can reduce the cost of batch production, improve the overall production efficiency, and thus reduce the cost per unit product; 12-inch ingots can accommodate more chips, and more products can be produced in a single production, increasing the output.

[0017] 3. The present invention adopts an advanced splicing technology to splice the cut fan-shaped wafers, which can reduce the defects caused by splicing, improve the overall quality and performance of the ingot. The splicing method can adapt to the chip requirements of different sizes and types, providing greater flexibility and diversity, promoting the development of splicing technology, and improving the overall technical level. The 12-inch silicon carbide ingot grown from the 12-inch silicon carbide seed crystal prepared by the preparation method of the present invention can meet the needs of the semiconductor industry for larger-sized ingots, enhance competitiveness, and better adapt to market changes.

[0018] The following will further elaborate on the present invention in conjunction with the drawings and embodiments. Description of the Drawings

[0019] Figure 1 is a flowchart of a method for preparing a 12-inch silicon carbide seed crystal based on water-jet guided laser provided by an embodiment of the present invention; Figure 2 is a schematic structural diagram of a vacuum chuck provided by an embodiment of the present invention; Figure 3 is Figure 2 a partial enlarged view of the lower circle part in Figure 4 is a schematic diagram of a SiC wafer in the two-dimensional coordinate system of a camera provided by an embodiment of the present invention; Figure 5 is a schematic diagram of wafer cutting provided by an embodiment of the present invention; Figure 6 is a schematic diagram of wafer splicing provided by an embodiment of the present invention. Detailed Embodiments

[0020] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in combination with the accompanying drawings and specific embodiments, will provide a detailed description of a 12-inch silicon carbide seed crystal based on water-guided laser and its preparation method proposed according to the present invention.

[0021] The foregoing and other technical contents, features and effects of the present invention can be clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are only for reference and illustration, and are not used to limit the technical solution of the present invention.

[0022] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant are intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the said element.

[0023] Example 1 In order to solve the above problems existing in the prior art, this embodiment proposes a preparation method for a 12-inch silicon carbide (SiC) seed crystal based on water-guided laser. This preparation method uses a micro-jet water-guided laser cutting technique to cut a small-sized SiC wafer into fan-shaped wafers, and then combines multiple fan-shaped wafers into a 12-inch SiC seed crystal through a high-precision splicing technique. Specifically, as Figure 1 shown, the preparation method of this 12-inch silicon carbide seed crystal includes the following steps: S1: Obtain five SiC wafers of a preset size.

[0024] Specifically, five SiC wafers with the same thickness are obtained from the same SiC ingot. In this embodiment, the selected SiC ingot has a diameter of approximately 200 mm and a type of 4H-SiC, 6H-SiC or 3C-SiC. Therefore, the five obtained SiC wafers are all wafers with a diameter of approximately 200 mm.

[0025] S2: Fix the first SiC wafer among the five SiC wafers on a vacuum chuck, and adjust the perpendicularity of the laser micro-jet nozzle of the laser micro-jet processing equipment to the surface of the first SiC wafer, so that the laser micro-jet ejected from the laser micro-jet nozzle is perpendicular to the first SiC wafer during the cutting process.

[0026] Step S2 of this embodiment specifically includes the following steps: S2.1: Fix the marking surface of the first SiC wafer upward on the vacuum chuck, and adjust the horizontal position of the first SiC wafer according to the position of the notch (or positioning edge) on the first SiC wafer.

[0027] Specifically, before cutting the first SiC wafer, first install the first SiC wafer and place it on the vacuum chuck. Please refer to Figure 2 and Figure 3 , where Figure 2 is the overall structural schematic diagram of the vacuum chuck; Figure 3 is Figure 2 The partial enlarged schematic diagram of the circled part in. The vacuum chuck includes a chuck body and a plurality of mounting threaded holes provided on the chuck body for fixing the vacuum chuck on the workbench, and the SiC wafer is placed on the chuck body during the cutting process.

[0028] The laser microjet nozzle of the laser microjet processing equipment of this embodiment is fixed above the vacuum chuck, and the perpendicularity between the laser microjet nozzle and the first SiC wafer is adjusted so that the laser microjet ejected from the laser microjet nozzle is perpendicular to the first SiC wafer during the cutting process.

[0029] Furthermore, adjust the horizontal position of the first SiC wafer according to the position of the notch on the first SiC wafer. Specifically, please refer to Figure 4 , Figure 4 is a schematic diagram of a SiC wafer in the two-dimensional coordinate system of the camera provided by an embodiment of the present invention. In this embodiment, the camera of the laser microjet processing equipment is used to adjust the position of the notch on the first SiC wafer so that the center of the two-dimensional coordinate axis on the camera observation surface coincides with the center of the first SiC wafer, and the notch is symmetric about the Y axis of the two-dimensional coordinate axis. As Figure 4 shown, the notch is located at the lowest position where the SiC wafer intersects the Y axis.

[0030] S2.2: Connect the vacuum chuck to the vacuum pump, turn on the vacuum pump, and control the vacuum pressure below -5 pa to adsorb the first SiC wafer to the surface of the vacuum chuck through negative pressure.

[0031] Specifically, a vacuum pipeline connection hole is provided in the middle of the suction cup body of the vacuum suction cup. Vacuum is extracted through the vacuum pipeline connection hole to fix the first SiC wafer, preventing position movement during the processing. Further, the vacuum suction cup is connected to a vacuum pump through a pipeline. When the vacuum pump is turned on, the first SiC wafer is adsorbed onto the surface of the vacuum suction cup by negative pressure, ensuring no shaking and guaranteeing the processing quality. Preferably, the vacuum pressure is controlled below -5 Pa.

[0032] S2.3: Calibrate the angle of the laser microjet, adjust the perpendicularity between the laser microjet and the surface of the first SiC wafer so that the laser microjet is perpendicular to the surface of the first SiC wafer to ensure the cutting accuracy. Subsequently, set the cutting parameters.

[0033] The cutting parameters include the rated power of the laser of the laser microjet processing equipment, the wavelength of the laser, the pulse frequency of the laser, the nozzle diameter of the laser microjet processing equipment, and the water pressure. In this embodiment, the laser of the laser microjet processing equipment uses a green nanosecond pulsed laser. The rated power of the laser is set to 200 W, the wavelength is set to 532 nm, the pulse frequency is set to 8 KHZ, a nozzle with a diameter of 60 μm is selected, the water pressure is set to be greater than 200 bar, and the resistivity of pure water is greater than 15 ΩM / cm 3 。

[0034] S3: Use the laser microjet to cut the first SiC wafer to obtain a first sector slice with a preset angle and radius.

[0035] Please refer to Figure 5 , Figure 5 which is a schematic diagram of wafer cutting provided by an embodiment of the present invention. Among them, Figure 5 (a) in it is a schematic diagram of cutting the first SiC wafer; Figure 5 (b) in it is a schematic diagram of cutting the second SiC wafer; Figure 5 (c) in it is a schematic diagram of cutting the third SiC wafer; Figure 5 (d) in it is a schematic diagram of cutting the fourth SiC wafer; Figure 5 (e) in it is a schematic diagram of cutting the fifth SiC wafer. In this step, first, set the first cutting path for the first SiC wafer so that the cut first sector slice takes the Y-axis of the two-dimensional coordinate axis as the central axis and the first intersection point of the Y-axis and the first SiC wafer as the center of the circle, where the first intersection point is the intersection point far from the notch. Specifically, as Figure 5As shown in (a) therein, on the observation surface of the camera, the first SiC wafer has two intersections with the Y-axis, including a second intersection (the lowermost intersection in the figure) located at the notch and a first intersection (the uppermost intersection in the figure) away from the notch. In this embodiment, with the first intersection as the center and the Y-axis of the two-dimensional coordinate axis as the axis of symmetry, a first cutting path for the first sector slice is constructed. That is to say, one side of the first sector slice is offset 36° to the left from the first intersection, and the other side is offset 36° to the right from the first intersection. The lengths of both sides are 152 mm. After the first cutting path is constructed, according to the first cutting path, reciprocating cutting is performed using a laser microjet. First, the two sides of the first sector slice are cut, and then the arc is cut, so as to obtain a first sector slice with an angle of 72° and a radius of 152 mm. Among them, the cutting speed is 5 mm / s, and the cutting power is 10 W.

[0036] After the first sector slice is cut, unloading is performed. When unloading, in order to reduce the risk of chipping, first remove the vacuum chuck, use an air gun to blow off the water on the back of the vacuum chuck, and then use a feeler gauge to pry off the first sector slice formed by cutting.

[0037] S4: Replace the first SiC wafer in Steps S1 to S3 with the remaining four SiC wafers among the five SiC wafers respectively, and sequentially execute Steps S1 to S3 to obtain a second sector slice, a third sector slice, a fourth sector slice, and a fifth sector slice having the same radius as the first sector slice respectively.

[0038] In this embodiment, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice have the same angle as the first sector slice, all being 72°. In another embodiment of the present invention, the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice may have different angles, as long as the sum of the angles of the five sector slices is 360°.

[0039] Specifically, after the cut first sector slice is cut and removed, fix the second SiC wafer on the vacuum chuck and adjust the vertical position of the second SiC wafer and the laser microjet, and ensure that the position of the notch on the second SiC wafer is the same as the position of the notch on the first SiC wafer; set the second cutting path of the second SiC wafer so that the central axis of the cut second sector slice rotates 72° counterclockwise relative to the Y-axis of the two-dimensional coordinate axis. Subsequently, cut the second SiC wafer according to the second cutting path to obtain a second sector slice with an angle of 72° and a radius of 152 mm, as Figure 5 shown in (b) therein.

[0040] Subsequently, the third SiC wafer, the fourth SiC wafer, and the fifth SiC wafer are successively cut. During the cutting process, the positions of the notch ports of the third SiC wafer, the fourth SiC wafer, and the fifth SiC wafer are the same as those of the notch port on the first SiC wafer, as Figure 4 shown. During the cutting process, the central axis of the third cutting path of the third sector slice rotates counterclockwise by 144° with respect to the Y-axis of the two-dimensional coordinate axis, as Figure 5 shown in (c) of Figure 5 ; the central axis of the fourth cutting path of the fourth sector slice rotates counterclockwise by 216° with respect to the Y-axis of the two-dimensional coordinate axis, as Figure 5 shown in (d) of

[0041] ; the central axis of the fifth cutting path of the fifth sector slice rotates counterclockwise by 288° with respect to the Y-axis of the two-dimensional coordinate axis, as Figure 5 shown in (e) of

[0041] . Specifically, the third SiC wafer is fixed on the vacuum chuck and the vertical position with respect to the laser microjet is adjusted, and it is ensured that the positions of the notch ports on the third SiC wafer are the same; the third cutting path is set such that the central axis of the third SiC wafer rotates counterclockwise by 144° with respect to the Y-axis of the two-dimensional coordinate axis. Subsequently, the third SiC wafer is cut according to the third cutting path to obtain a third sector slice with an angle of 72° and a radius of 152 mm.

[0042] The cutting processes of the fourth sector slice and the fifth sector slice are as above, and the only difference is the position of the central axis of the cutting path, which will not be elaborated here.

[0043] It should be noted that when cutting different sector slices in this embodiment, different positions on different SiC wafers are selected for the following main reasons: (1) Crystal phase consistency: The crystal phase of the seed crystal must be consistent with that of the target crystal. Inconsistency may lead to structural defects, uneven growth, and performance problems. To ensure crystal phase consistency, sector slices at different positions are taken for splicing, so that the obtained 12-inch silicon carbide seed crystal has a consistent crystal type, and thus a 2-inch silicon carbide ingot with more stable performance can be grown subsequently; (2) Performance impact: Consistent crystal phases ensure uniform electrical and mechanical properties of the crystal, avoiding problems such as uneven resistivity and reduced charge carrier mobility, thereby ensuring device performance. (3) Detection and optimization: In practical applications, it is necessary to detect the crystal phase consistency of the seed crystal and optimize the growth process when necessary to ensure crystal quality.

[0044] Furthermore, in order to obtain better crystal phase consistency, in this embodiment, five SiC wafers obtained from the same SiC ingot are sequentially used as the first SiC wafer, the second SiC wafer, the third SiC wafer, the fourth SiC wafer, and the fifth SiC wafer from top to bottom or from bottom to top. Subsequently, corresponding first sector slices, second sector slices, third sector slices, fourth sector slices, and fifth sector slices are obtained by cutting in sequence. Finally, the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice are spliced and polished in sequence to obtain a final 12-inch SiC seed crystal.

[0045] S5: Splice the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice to obtain a 12-inch SiC seed crystal.

[0046] Specifically, the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice are adhesively bonded in sequence to obtain the adhesively bonded seed crystal; the adhesively bonded seed crystal is polished to eliminate surface defects, and finally a 12-inch silicon carbide seed crystal capable of being used for the growth of a 12-inch silicon carbide ingot is obtained, as Figure 6 shown. During the splicing process, positioning is carried out under a high-power microscope so that the edges of all sector slices can form a smooth circle, and then a high-temperature resistant glue is used for bonding. After bonding, a complete 12-inch silicon carbide seed crystal is formed.

[0047] Specifically, first, the surfaces of the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice are chemically activated or laser-treated to remove surface contamination and expose fresh crystal surfaces. Subsequently, the surfaces are cleaned with high-purity solvents (such as acetone and alcohol) to ensure no organic matter or particle residue. Then, the individual sector slices are precisely aligned, fixed using jigs or vacuum suction cups, and high-temperature sintering, bonding, or welding operations are carried out. In this embodiment, high-temperature ceramic glue or epoxy resin is used as the bonding agent to ensure the stability of the bonding agent at high temperatures and good adhesion to the SiC surface. After bonding, it is slowly cooled to room temperature to avoid cracks caused by thermal stress.

[0048] Finally, an optical microscope or an electron microscope is used to check the flatness and bonding strength of the splicing joint; electrical or mechanical property tests are carried out on the spliced seed crystal to ensure that it meets the requirements for subsequent growth or application.

[0049] Another aspect of the present invention also provides a 12-inch silicon carbide seed crystal based on water-jet guided laser, which is prepared by the above-mentioned preparation method. This 12-inch silicon carbide seed crystal can be used for growing 12-inch silicon carbide ingots. The larger ingots can reduce the cost of batch production, improve the overall production efficiency, and thus reduce the cost per unit product. The 12-inch ingots can accommodate more chips, and a single production can produce more products, increasing the output.

[0050] The present invention proposes a preparation method for a 12-inch silicon carbide seed crystal based on water-jet guided laser. By using a micro-jet laser processing device for wafer cutting, the wafer chipping can be effectively reduced, and SiC seed crystals that can be directly used for splicing can be obtained, reducing the back-end processing process and improving the production efficiency at the same time. The present invention adopts the micro-jet water-jet guided laser cutting technology to cut small-size SiC wafers into fan-shaped wafers, and then combines them into 12-inch seed crystals through high-precision splicing technology. Cutting and splicing smaller wafers to obtain larger 12-inch seed crystals can improve the material utilization rate, reduce waste, and lower the production cost.

[0051] The present invention uses advanced splicing technology to splice the cut fan-shaped wafers, which can reduce the defects generated during splicing, improve the overall quality and performance of the ingot. The splicing method can adapt to the requirements of different sizes and types of chips, providing greater flexibility and diversity, promoting the development of splicing technology, and improving the overall technical level. The 12-inch silicon carbide ingots grown from the 12-inch silicon carbide seed crystals prepared by the preparation method of the present invention can meet the needs of the semiconductor industry for larger-size ingots, enhance the competitiveness, and better adapt to market changes.

[0052] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a 12-inch silicon carbide seed crystal based on water-jet guided laser, characterized in that, Including: S1: Obtain five SiC wafers of a preset size; S2: Fix the first SiC wafer among the five SiC wafers on a vacuum chuck, and adjust the perpendicularity of the laser microjet nozzle of the laser microjet processing equipment to the surface of the first SiC wafer, so that the laser microjet ejected from the laser microjet nozzle is perpendicular to the first SiC wafer during the cutting process; S3: Use the laser microjet to cut the first SiC wafer to obtain a first sector slice with a preset angle and radius; S4: Replace the first SiC wafer in steps S1 to S3 with the remaining four SiC wafers among the five SiC wafers respectively, and sequentially execute steps S1 to S3 to obtain a second sector slice, a third sector slice, a fourth sector slice, and a fifth sector slice that have the same radius as the first sector slice; S5: Splice the first sector slice, the second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice to obtain a 12-inch SiC seed crystal.

2. The preparation method of a 12-inch silicon carbide seed crystal based on water-guided laser according to claim 1, wherein, The S2 includes: S2.1: Fix the first SiC wafer to the vacuum chuck, and adjust the horizontal position of the first SiC wafer according to the notch on the first SiC wafer; S2.2: Connect the vacuum chuck to a vacuum pump, turn on the vacuum pump, and control the vacuum pressure below -5 Pa to adsorb the first SiC wafer to the surface of the vacuum chuck by negative pressure; S2.3: Adjust the perpendicularity of the laser microjet of the laser microjet processing equipment to the surface of the first SiC wafer, so that the laser microjet is perpendicular to the surface of the first SiC wafer, and set the cutting parameters; The cutting parameters include the rated power of the laser of the laser microjet processing equipment, the wavelength of the laser, the pulse frequency of the laser, the nozzle diameter of the laser microjet processing equipment, and the water pressure; Adjusting the horizontal position of the first SiC wafer according to the notch on the first SiC wafer includes: Using the camera on the laser microjet processing equipment to adjust the position of the notch on the first SiC wafer, so that the center of the two-dimensional coordinate axis on the camera viewing surface coincides with the center of the SiC wafer, and the notch is symmetric about the Y-axis of the two-dimensional coordinate axis.

3. The method for preparing a 12-inch silicon carbide seed crystal based on water-jet guided laser according to claim 2, wherein The S3 includes: Set a first cutting path, so that the cut first sector slice takes the Y-axis of the two-dimensional coordinate axis as the central axis and the first intersection point of the Y-axis and the first SiC wafer as the center of the circle, where the first intersection point is the intersection point of the Y-axis and the first SiC wafer far from the notch; According to the first cutting path, use the laser microjet to cut to obtain the first sector slice.

4. The preparation method of a 12-inch silicon carbide seed crystal based on water-guided laser according to claim 1, wherein, The second sector slice, the third sector slice, the fourth sector slice, and the fifth sector slice have the same angle as the first sector slice, all of which are 72°.

5. The preparation method of a 12-inch silicon carbide seed crystal based on water-jet guided laser according to claim 4, wherein, In the S4, the process of cutting the second SiC wafer to form the second sector slice includes: Fix the second SiC wafer on the vacuum chuck and adjust the vertical position of the second SiC wafer and the laser microjet, and ensure that the notch on the second SiC wafer is in the same position as the notch on the first SiC wafer; set the second cutting path of the second SiC wafer so that the central axis of the second SiC wafer rotates 72° counterclockwise relative to the Y-axis of the two-dimensional coordinate axis, and obtain a second sector slice with an angle of 72° according to the second cutting path.

6. The preparation method of a 12-inch silicon carbide seed crystal based on water-jet guided laser according to claim 4, characterized in that, During the cutting process, the central axis of the third cutting path of the third sector slice rotates 144° counterclockwise relative to the Y-axis of the two-dimensional coordinate axis; the central axis of the fourth cutting path of the fourth sector slice rotates 216° counterclockwise relative to the Y-axis of the two-dimensional coordinate axis; the central axis of the fifth cutting path of the fifth sector slice rotates 288° counterclockwise relative to the Y-axis of the two-dimensional coordinate axis.

7. The preparation method of a 12-inch silicon carbide seed crystal based on water-guided laser according to claim 1, wherein, The S5 includes: Bond the first sector slice, the second sector slice, the third sector slice, the fourth sector slice and the fifth sector slice in sequence to obtain a bonded seed crystal; Polish the seed crystal to eliminate surface defects and obtain a 12-inch silicon carbide seed crystal for the growth of a 12-inch silicon carbide ingot.

8. A 12-inch silicon carbide seed crystal based on water-jet guided laser, characterized in that, The 12-inch silicon carbide seed crystal is prepared by the preparation method according to any one of claims 1 to 7.

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