Method for slicing large-size diamond crystal

Abstract

A method for slicing a large-size diamond crystal, comprising: fixing a seed crystal surface of a diamond crystal on a first tool, and adjusting an angle between a micro-jet laser and a growth surface; setting cutting parameters and determining a cutting origin; fixing the growth surface on a second tool; reciprocally cutting the diamond crystal along a first rectangular cutting path until a cutting depth reaches a first preset depth; reciprocally cutting the diamond crystal along a second rectangular cutting path until the cutting depth reaches a second preset depth; reciprocally cutting from the cutting origin to a third preset depth; flipping the first tool and the second tool together with the diamond crystal along the centerline of the first tool and repeating the foregoing steps until the diamond crystal is completely cut off; and continuing to cut a step-shaped cutting surface to form a flat cutting surface. Cutting is performed layer by layer by means of rectangular kerf expansion and flip-cutting, thus avoiding the influence of accumulated water in the cutting kerf on the power of the micro-jet laser, and improving the cutting efficiency.

Description

A method for slicing large diamond crystals Technical Field

[0001] This invention belongs to the field of microfluidic laser processing technology, specifically relating to a method for slicing large-size diamond crystals. Background Technology

[0002] Single-crystal diamond possesses an ultra-wide bandgap, low dielectric constant, high breakdown voltage, high intrinsic electron and hole mobility, and superior radiation resistance, making it the best-known wide-bandgap high-temperature semiconductor material. However, a major challenge currently facing the field of single-crystal diamond fabrication is achieving the goal of fabricating inch-scale ultra-large wafers using chemical vapor deposition (CVD) technology. Overcoming this technological bottleneck is crucial for driving the development of the entire industry. Furthermore, in CVD fabrication processes, diamond growth can be subdivided into two main paths based on the type of substrate used: heteroepitaxial growth and homoepitaxial growth. Currently, most mainstream inch-scale large-size single-crystal diamond materials on the market rely heavily on the successful application of heteroepitaxial technology, which to some extent limits the rapid development of homoepitaxial devices, causing their application exploration to lag behind that of heteroepitaxial devices. Therefore, how to cut single-crystal diamond wafers from high-quality, large-size single-crystal diamond crystals has become a key issue.

[0003] Microfluidic laser technology is widely used in precision machining due to its clean and sharp cuts, lack of thermal stress, and narrow cut width. For diamond slicing, microfluidic laser processing is a good choice. However, during the slicing process, as the cutting depth increases, water that cannot be drained in time often accumulates within the kerf. This water can disrupt the total internal reflection effect of the microfluidic laser, limiting the cutting depth. Furthermore, the larger the cut size, the more severe the water accumulation, which also limits the application of microfluidic lasers in large-size diamond slicing. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a method for slicing large-size diamond crystals. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] This invention provides a method for slicing large-size diamond crystals, comprising:

[0006] S1: Fix the seed crystal face of the diamond crystal to be cut on the first tooling, and adjust the angle between the micro-jets laser and the growth surface of the diamond crystal. The diamond crystal includes a seed crystal face and a growth surface that is opposite to and parallel to the seed crystal face.

[0007] S2: Set the cutting parameters of the microfluidic laser processing equipment and determine the position of the cutting origin;

[0008] S3: Fix the growth surface of the diamond crystal on the second tooling, wherein the center line of the first tooling and the center line of the second tooling are on the same straight line;

[0009] S4: Starting from the cutting origin, the diamond crystal is cut reciprocally along the first rectangular cutting trajectory until the cutting depth reaches the first preset depth, then the cutting origin is returned.

[0010] S5: Starting from the cutting origin, the diamond crystal is cut reciprocally along the second rectangular cutting trajectory until the cutting depth reaches the second preset depth, then the cutting origin is returned.

[0011] S6: Starting from the cutting origin, cut back and forth along the length of the diamond crystal to a third preset depth;

[0012] S7: Simultaneously rotate the first tooling and the second tooling, along with the diamond crystal, 180° along the center line of the first tooling and repeat steps S4 to S6 until the diamond crystal is completely cut off, forming a smooth, stepless cutting surface fixed on the first tooling and a stepped cutting surface fixed on the second tooling.

[0013] S8: Continue cutting the stepped cutting surface fixed on the second tooling to form a flat cutting surface.

[0014] In one embodiment of the present invention, S1 includes:

[0015] The seed crystal facet of the diamond crystal is fixed to the first tooling by adsorption or bonding, and the seed crystal facet is perpendicular to the center line of the first tooling. The first tooling can be freely rotated along its own center line. The diamond crystal includes a seed crystal facet and a growth facet that is opposite to and parallel to the seed crystal facet. Both the seed crystal facet and the growth facet are surfaces enclosed by the length direction and the width direction of the diamond crystal.

[0016] Adjust the angle between the micro-jets generated by the micro-jets laser processing equipment and the growth surface of the diamond crystal so that the micro-jets laser is parallel to the growth surface.

[0017] In one embodiment of the present invention, S2 includes:

[0018] The cutting parameters of the microfluidic laser processing equipment are set, and the cutting parameters include at least the rated power, wavelength and pulse frequency of the laser, the nozzle diameter of the microfluidic laser, the water pressure of the microfluidic laser and the coupling power.

[0019] The micro-jets of the micro-jets in the micro-jets laser processing equipment are moved a distance of t+d+0.8×d from the growth surface of the diamond crystal toward the seed crystal surface. Then, the micro-jets laser is moved along the length of the diamond crystal to the outside of the diamond crystal and spaced a certain distance from the outer edge of the diamond crystal. The current point is set as the cutting origin, where t is the cutting thickness and d is the diameter of the micro-jets laser.

[0020] In one embodiment of the present invention, the laser of the microjets laser device is a green nanosecond pulsed laser with a rated power of 400W, a wavelength of 532nm, and a pulse frequency of 10kHz; the cutting water pressure of the microjets laser device is greater than 500bar, and the coupling power at a jet length of 40mm of the microjets laser is not less than 100W.

[0021] In one embodiment of the present invention, S4 includes:

[0022] The microjets laser cuts from the first side to the second side along the length of the diamond crystal, starting from the cutting origin. Then, it moves a first preset distance along the direction from the seed crystal surface toward the growth surface, and then cuts in the opposite direction from the second side to the first side along the length. The trajectories of the two cuts overlap. Then, it continues to cut along the same trajectory until the cutting depth reaches the first preset depth, and then returns to the cutting origin.

[0023] In one embodiment of the present invention, S5 includes:

[0024] The microjets laser cuts from the origin of the diamond crystal along the length of the crystal from the first side to the second side. Then, it moves a second preset distance along the direction from the seed crystal surface toward the growth surface, and then cuts back from the second side to the first side along the length of the crystal. The trajectories of the two cuts overlap. The cutting continues along the same trajectory until the cutting depth reaches the second preset depth, and then the laser returns to the origin of the crystal.

[0025] In one embodiment of the present invention, the first preset distance is 0.8d, the second preset distance is 0.5d, the first preset depth is 0.2h, the second preset depth is 0.4h, and the third preset depth is 0.5h, where h represents the width of the diamond crystal along the cutting direction.

[0026] In one embodiment of the present invention, S7 includes:

[0027] The first tooling and the second tooling, together with the diamond crystal, are simultaneously rotated 180° along the center line of the first tooling, and steps S4 to S6 are repeated until the diamond crystal is completely cut through, forming a seed crystal fixed on the first tooling and a growth crystal fixed on the second tooling. The cutting surface of the seed crystal is planar, and the cutting surface of the growth crystal is stepped.

[0028] In one embodiment of the present invention, S8 includes:

[0029] The microjets laser is moved 0.8d along the cutting origin in the direction from the seed crystal surface toward the growth surface, and the moved position is redefined as the new cutting origin. The laser is then used to cut back and forth along the length direction to a depth of 0.5h from the new cutting origin.

[0030] The second tooling is rotated 180°, and the cutting is repeated from the new cutting origin to the cutting start point until the slice is completed. The cutting surface of the diamond crystal is a flat surface, where d is the diameter of the microjets laser and h represents the width of the diamond crystal along the cutting direction.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The large-size diamond slicing process of this invention performs deep cutting layer by layer through rectangular slit widening and flipping cutting, avoiding the influence of water accumulation in the cutting groove on the micro-jets laser power, thereby achieving effective cutting of large-size diamond crystals; at the same time, the steps formed by layer-by-layer cutting are cut and surface-trimmed, so that both the seed crystal surface and the growth surface after slicing have good cutting surfaces, reducing the time and production cost of subsequent wafer polishing, ensuring slicing quality and improving slicing efficiency.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] Figure 1 is a flowchart of a method for slicing large-size diamond crystals according to an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the dimension and orientation of a diamond crystal to be cut according to an embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of the fixing of a diamond crystal according to an embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of angle adjustment of a micro-jet laser provided in an embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of the process for determining the position of the cutting origin according to an embodiment of the present invention;

[0039] Figure 6 is a schematic diagram of a rectangular cutting trajectory provided in an embodiment of the present invention;

[0040] Figure 7 is a schematic diagram of a slice with one side cut according to an embodiment of the present invention;

[0041] Figure 8 is a schematic diagram of a slice after the two sides have been cut following the flipping process, according to an embodiment of the present invention.

[0042] Figure 9 is a schematic diagram of a step surface finishing provided in an embodiment of the present invention;

[0043] Figure 10 is a schematic diagram of a sliced ​​product provided in an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1-Diamond crystal; 2-First tooling; 3-Second tooling; 4-Microjet laser; 5-Seed crystal; 6-Grown crystal. Embodiments of the present invention

[0046] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of a method for slicing large-size diamond crystals according to the present invention is provided in conjunction with the accompanying drawings and specific embodiments.

[0047] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element.

[0049] Example 1

[0050] Please refer to Figure 1, which is a flowchart of a method for slicing large-size diamond crystals according to an embodiment of the present invention. The slicing method specifically includes the following steps:

[0051] S1: Fix the seed crystal surface of the diamond crystal 1 to be cut on the first tooling 2, and adjust the angle between the micro-jets laser 4 and the growth surface of the diamond crystal 1.

[0052] Please refer to Figure 2, which is a schematic diagram of the dimensions and orientation of a diamond crystal to be cut according to an embodiment of the present invention. The diamond crystal 1 is rectangular in shape, with a length of L, a width of h, and a thickness of T. The length direction is parallel to the X-axis, the width direction is parallel to the Y-axis, and the thickness direction is parallel to the Z-axis. A microfluidic laser processing device is located above the diamond crystal 1, and uses a microfluidic laser to cut the diamond crystal 1 into different thicknesses. The diamond crystal 1 has a seed crystal surface and a growth surface opposite to and parallel to the seed crystal surface. Both the seed crystal surface and the growth surface are surfaces enclosed by the length and width directions, respectively.

[0053] Specifically, the seed crystal face of the diamond crystal 1 to be cut is fixed on the first tooling 2 by adsorption or bonding, and the seed crystal face of the diamond crystal 1 is perpendicular to the center line of the first tooling 2, as shown in Figure 3.

[0054] The angle between the microfluidic laser 4 and the growth surface of the diamond crystal 1 is adjusted so that the microfluidic laser 4 and the growth surface of the diamond crystal 1 are completely parallel, as shown in Figure 4. Furthermore, the first fixture 2 can freely rotate along its own centerline.

[0055] S2: Set the cutting parameters of the microfluidic laser processing equipment and determine the cutting origin.

[0056] First, set the cutting parameters of the microfluidic laser processing equipment. The cutting parameters should include at least the rated power, wavelength and pulse frequency of the laser, the nozzle diameter of the microfluidic laser, the water pressure of the microfluidic laser and the coupling power.

[0057] In this embodiment, the laser used in the microfluidic laser processing equipment is a green nanosecond pulsed laser with a rated power of 400W, an emitted laser wavelength of 532nm, and a pulse frequency of 10kHz. The nozzle for the microfluidic laser is a 60μm diameter nozzle, the water pressure is greater than 500bar, and the resistivity of the pure water is greater than 15ΩM / cm. 3 The helium flow rate is not less than 0.1 L / min, and the coupling power at the jet length of the microjets laser is not less than 100 W.

[0058] The position of the micro-jets laser 4 in the micro-jets laser device is moved along the Z-axis (thickness direction of the diamond crystal 1) from the growth surface of the diamond crystal 1 towards the seed crystal surface by a distance of t+d+0.8×d. The micro-jets laser 4 is then moved along the X-axis (length direction of the diamond crystal 1) to the outside of the diamond crystal and spaced a certain distance from the outer edge of the diamond crystal 1. The current point is set as the cutting origin, where t is the cutting thickness and d is the diameter of the micro-jets laser 4.

[0059] Please refer to Figure 5, which is a schematic diagram of the process for determining the cutting origin position according to an embodiment of the present invention. A micro-jets laser 4 (shown as the rightmost dashed circle in Figure 5) is attached to the growth surface of the diamond crystal 1 and moved (t+d+0.8×d) mm from the growth surface towards the seed crystal surface. Then, the micro-jets laser 4 is moved 2 mm outside the crystal along the length direction of the diamond crystal 1, and this point is set as the cutting origin (shown as the uppermost circle in Figure 5).

[0060] S3: Fix the growth surface of the diamond crystal 1 to be cut on the second tooling 3. The center line of the first tooling 2 and the center line of the second tooling 3 are on the same straight line, as shown in Figure 7.

[0061] Specifically, the growth surface of the diamond crystal 1 to be cut is adsorbed or pasted onto the second fixture 3, thus completely fixing both sides of the diamond crystal 1. The center line of the first fixture 2 and the center line of the second fixture 3 are collinear, and the center line of the first fixture 2 is used as the adjustment reference. Furthermore, the second fixture 3 can freely rotate along its own center line.

[0062] S4: Starting from the cutting origin, the diamond crystal is cut back and forth along the first rectangular cutting trajectory until the cutting depth reaches the first preset depth, then the cutting origin is returned.

[0063] When cutting begins, the micro-jets laser 4 starts from the cutting origin and cuts along the length direction (X-axis direction) of the diamond crystal 1 from the first side to the second side. Then it moves along the thickness direction to the growth surface by a first preset distance, and then cuts in the opposite direction from the second side to the first side along the length direction. The trajectories of the two cuts partially overlap. Then it continues to cut along the same trajectory until the cutting depth reaches the first preset depth and then returns to the cutting origin.

[0064] Please refer to Figure 6, which is a schematic diagram of a rectangular cutting trajectory provided by an embodiment of the present invention. In a specific embodiment, during cutting, a length of (L+4) mm is first cut along the length direction of the diamond crystal 1 (as shown by the solid line along the X-axis in Figure 6(a)), so that the cutting point moves from the initial cutting origin (moved 2 mm away from the first side of the crystal along the length direction of the diamond crystal 1) to 2 mm away from the second side of the diamond crystal 1; then it moves (0.8d) mm along the direction of the seed crystal towards the growth surface (as shown by the short solid line along the Z-axis in Figure 6(a)); then a length of (L+4) mm is cut in the opposite direction along the length direction (as shown by the dashed line along the X-axis in Figure 6(a)). The two length direction cuts form a pressing tool with a pressing tool amount of (0.2d) mm (that is, the trajectory of each cut has a certain width, which is equal to the diameter d of the micro-jets laser 4, and there is an overlap of (0.2d) mm between the two cuts), and then returns to the cutting origin. A rectangular cutting trajectory with a length of (L+4) mm and a width of (0.8d) mm is formed, and the resulting kerf width is (1.8d) mm (as shown in Figure 6(b)). The cutting is then repeated along this trajectory until a depth of (0.2h) mm, at which point the trajectory returns to the origin. Because the kerf is enlarged, water accumulation during the cutting process is effectively drained, improving cutting efficiency. Here, L is the crystal length, d is the microjet diameter, and h is the width of the diamond crystal 1, i.e., the total slicing depth. Preferably, the pressure applied by the cutting trajectory is not less than 0.1d.

[0065] S5: Starting from the cutting origin, the diamond crystal is cut back and forth along the second rectangular cutting trajectory until the cutting depth reaches the first preset depth, then the cutting origin is returned.

[0066] The microjets laser cuts along the length of the diamond crystal from the first side to the second side, starting from the cutting origin. Then, it moves a second preset distance from the seed crystal to the growth surface, and then cuts back along the length from the second side to the first side, with the two cutting trajectories overlapping. Cutting continues along the same trajectory until the cutting depth reaches the second preset depth, after which the laser returns to the cutting origin. Preferably, the pressure amount formed by the cutting trajectory is not less than 0.1d.

[0067] Similarly, in this embodiment, the cutting continues along the crystal length direction from the cutting origin, cutting a length of (L+4) mm, then moving along the seed crystal surface to the growth surface by (0.5d) mm, and then cutting back along the length direction by (L+4) mm. The two length direction cuts form a pressing tool with a pressing amount of (0.5d) mm, and then returning to the cutting origin; forming a rectangular cutting trajectory with a length of (L+4) mm and a width of (0.5d) mm. The cutting kerf width formed by this trajectory is (1.5d) mm, and this trajectory is (0.3d) mm narrower than the previous trajectory. The cutting is repeated along this trajectory until a depth of (0.4h) mm is reached, at which point the cutting returns to the origin.

[0068] S6: Starting from the cutting origin, cut back and forth along the length of the diamond crystal to a third preset depth.

[0069] Specifically, the crystal is cut repeatedly from the origin along its length for a length of (L+4) mm to a depth of (0.5h) mm. The cutting state at this point is shown in Figure 7. In this embodiment, the depth is measured using a feeler gauge with a diameter of 0.06 mm.

[0070] S7: Simultaneously rotate the first and second fixtures, along with the diamond crystal, 180° along the centerline of the first fixture and repeat steps S4 to S6 until the diamond crystal is completely cut off, forming a smooth, stepless cutting surface fixed on the first fixture and a stepped cutting surface fixed on the second fixture.

[0071] Specifically, the first fixture 2 and the second fixture 3, together with the diamond crystal, are simultaneously rotated 180° along the axis of the first fixture 2 and steps S4 to S6 are repeated until the crystal is completely cut through. At this point, the seed crystal 5 and the growth crystal 6 are completely separated. The seed crystal 5 is fixed on the first fixture 2, and the growth crystal 6 is fixed on the second fixture 3. The cutting surface of the seed crystal 5 is smooth without steps, while the cutting surface of the growth crystal 6 is stepped, as shown in Figure 8.

[0072] S8: Continue cutting the stepped cutting surface fixed on the second tooling to form a flat cutting surface.

[0073] Specifically, the microjets laser is moved (0.8d) mm along the direction from the seed crystal surface toward the growth surface from the current cutting origin, and the current point is redefined as the new cutting origin. Starting from the new cutting origin, the laser is reciprocated along the length direction with a length of (L+4) mm and a depth of (0.5h) mm, as shown in Figure 9.

[0074] Subsequently, the second fixture is rotated 180°, and the grown crystal is rotated 180° accordingly. The cutting length (L+4) mm is cut repeatedly with the new cutting origin as the cutting starting point until the slice is completed. The cut surface of the diamond crystal is a flat surface, as shown in Figure 10. Here, d is the diameter of the microjets laser, h represents the width of the diamond crystal along the cutting direction, and L represents the length of the diamond crystal.

[0075] Example 2

[0076] Based on Example 1, this example proposes another method for slicing large-size diamond crystals. The diamond crystal to be sliced ​​in this example is 50 (length) × 50 (width) × 1.1 (thickness) mm; the planned slicing thickness is t = 0.5 mm, dividing the crystal into two slices. The slicing method of this example includes:

[0077] Step 1: Fix the diamond to be cut on the first tooling 2 and adjust the angle between the micro-jets laser 4 and the growth surface of the diamond crystal 1.

[0078] First, the seed crystal face of the diamond crystal 1 to be cut is fixed on the first tooling 2 by adsorption, and the seed crystal face of the diamond crystal 1 is perpendicular to the center line of the first tooling 2.

[0079] Adjust the angle between the micro-jets laser 4 and the growth surface of the diamond crystal 1 so that the micro-jets laser 4 and the growth surface of the diamond crystal 1 are completely parallel and the diamond crystal 1 is completely perpendicular to the center line of the first tooling 2.

[0080] Step 2: Set the cutting parameters and cutting thickness of the microfluidic laser equipment.

[0081] Specifically, the laser in the micro-jets laser device is a green nanosecond pulsed laser with a rated power of 400W, a wavelength of 532nm, and a pulse frequency of 10kHz. The jet nozzle is a 60μm diameter nozzle, i.e., d=0.06mm. The micro-jets laser 4 is 6mm away from the diamond crystal 1 surface processing position. The water pressure is set to 600bar, the resistivity of pure water is greater than 15ΩM / cm3, the coupling power at the jet processing position is 110W, and the helium flow rate is maintained at 0.1L / min to ensure that the coupling power is not less than 100W after the jet is raised by 30mm.

[0082] A micro-jets laser 4 is attached to the growth surface of the diamond crystal 1 and moved 0.608 mm toward the seed crystal surface. The micro-jets laser 4 is then moved 2 mm outside the crystal and this point is set as the cutting origin.

[0083] Step 3: Fix the growth surface of the diamond crystal 1 to be cut onto the second tooling 3.

[0084] The growth surface of the diamond crystal 1 is adsorbed onto the second tooling 3 by vacuum adsorption, so that both sides of the diamond crystal 1 are completely fixed, and the center line of the first tooling 2 and the center line of the second tooling 3 are on the same straight line.

[0085] Step 4: Starting from the cutting origin, reciprocate along the first rectangular cutting trajectory to cut the diamond crystal until the cutting depth reaches the first preset depth, then return to the cutting origin.

[0086] During cutting, a 54mm length is first cut along the length direction of diamond crystal 1, then the cutting plane is moved 0.048mm along the growth surface, and then another 54mm length is cut in the opposite direction along the length. The two length cuts form a pressure cut (trajectory overlap), with a pressure cut amount of 0.012mm. The cutting plane then returns to the cutting origin, forming a rectangular cutting trajectory with a length of 54mm and a width of 0.048mm. The cutting width formed by the rectangular cutting trajectory is 0.108mm. The cutting is repeated along this rectangular cutting trajectory until a depth of 10mm, at which point the cutting origin is returned. Because the cutting kerf is widened to 0.108mm, the water accumulated during the cutting process is effectively drained, improving the cutting efficiency.

[0087] Step 5: Starting from the cutting origin, reciprocate cutting the diamond crystal 1 along the second rectangular cutting trajectory until the cutting depth reaches the second preset depth, then return to the cutting origin.

[0088] Specifically, continue cutting along the length of diamond crystal 1 from the cutting origin for 54 mm, then move 0.03 mm along the growth surface, and then cut another 54 mm along the length in the opposite direction. The two cuts along the length direction form a pressing cut (trajectory overlap), with a pressing cut amount of 0.03 mm. Then return to the cutting origin to form a rectangular cutting trajectory with a length of 54 mm and a width of 0.03 mm. The cutting width formed by this trajectory is 0.09 mm, which is 0.018 mm narrower than the previous trajectory. Then, cut along this trajectory in a loop until a depth of 20 mm is reached, and then return to the origin.

[0089] Step 6: Cut back and forth along the length of the diamond crystal 1 from the original cutting point to the third preset depth.

[0090] Specifically, a 54mm long cut is made along the length of the diamond crystal 1 from the cutting origin to a depth of 25mm. The cut at this point is shown in Figure 7. The cutting depth in the above steps is measured using a 0.06mm feeler gauge.

[0091] Step 7: Simultaneously rotate the first fixture 2 and the second fixture 3 along with the diamond crystal 1 by 180° and repeat steps 4 to 6 until the diamond crystal 1 is completely cut through; at this point, the seed crystal 5 is completely peeled off, the seed crystal 5 is fixed on the first fixture 2, the growth crystal 6 is fixed on the second fixture 3, and the cut surface of the seed crystal 5 is smooth without steps, while the cut surface of the growth crystal 6 is stepped. At this time, the cut of the crystal 1 is shown in Figure 8.

[0092] Step 8: Continue cutting the stepped cutting surface fixed on the second tooling to form a flat cutting surface.

[0093] Specifically, the microjets laser 4 is moved 0.048 mm along the cutting origin towards the growth crystal direction and redefined as the new cutting origin. Using this new cutting origin, the diamond crystal 1 is cut back and forth for a depth of 25 mm with a length of 54 mm. Then, the second fixture 3 is rotated 180°, and the growth crystal is rotated 180° accordingly. The cutting length of 54 mm is continued with the new cutting origin as the cutting starting point, and the cutting is repeated until the slice is completed. At this time, the growth crystal surface is flattened, and the crystal cutting surface is a flat surface.

[0094] Finally, the seed crystal 5 and the grown crystal 6 are removed from the first fixture 2 and the second fixture 3 respectively, thus completing the slicing process of the 50×50×1.1mm crystal. After slicing, the thickness of the seed crystal is 0.502mm, the thickness of the grown crystal is 0.5mm, and the cutting loss is 0.108mm.

[0095] The large-size diamond slicing process of this invention performs deep cutting layer by layer through rectangular slit widening and flipping cutting, avoiding the influence of water accumulation in the cutting channel on the power of the jet in the depth direction, thereby achieving effective cutting of large-size diamond crystals; at the same time, the steps formed by layer-by-layer cutting are cut and surface-trimmed, so that both the seed crystal surface and the growth surface after slicing have good cutting surfaces, reducing the time and production cost of subsequent wafer polishing, ensuring slicing quality and improving slicing efficiency.

[0096] In the several embodiments provided by this invention, it should be understood that the apparatus and methods disclosed in this invention can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of modules is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0097] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or in the form of hardware plus software functional modules.

[0098] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for slicing large-size diamond crystals, characterized in that, include: S1: Fix the seed crystal face of the diamond crystal to be cut on the first tooling, and adjust the angle between the micro-jets laser and the growth surface of the diamond crystal. The diamond crystal includes a seed crystal face and a growth surface that is opposite to and parallel to the seed crystal face. S2: Set the cutting parameters of the microfluidic laser processing equipment and determine the position of the cutting origin; S3: Fix the growth surface of the diamond crystal on the second tooling, wherein the center line of the first tooling and the center line of the second tooling are on the same straight line; S4: Starting from the cutting origin, the diamond crystal is cut reciprocally along the first rectangular cutting trajectory until the cutting depth reaches the first preset depth, then the cutting origin is returned. S5: Starting from the cutting origin, the diamond crystal is cut reciprocally along the second rectangular cutting trajectory until the cutting depth reaches the second preset depth, then the cutting origin is returned. S6: Starting from the cutting origin, cut back and forth along the length of the diamond crystal to a third preset depth; S7: Simultaneously rotate the first tooling and the second tooling, along with the diamond crystal, 180° along the center line of the first tooling and repeat steps S4 to S6 until the diamond crystal is completely cut off, forming a smooth, stepless cutting surface fixed on the first tooling and a stepped cutting surface fixed on the second tooling. S8: Continue cutting the stepped cutting surface fixed on the second tooling to form a flat cutting surface.

2. The method for slicing large-size diamond crystals according to claim 1, characterized in that, S1 includes: The seed crystal facet of the diamond crystal is fixed to the first tooling by adsorption or bonding, and the seed crystal facet is perpendicular to the center line of the first tooling. The first tooling can be freely rotated along its own center line. The diamond crystal includes a seed crystal facet and a growth facet that is opposite to and parallel to the seed crystal facet. Both the seed crystal facet and the growth facet are surfaces enclosed by the length direction and the width direction of the diamond crystal. Adjust the angle between the micro-jets generated by the micro-jets laser processing equipment and the growth surface of the diamond crystal so that the micro-jets laser is parallel to the growth surface.

3. The method for slicing large-size diamond crystals according to claim 1, characterized in that, S2 includes: The cutting parameters of the microfluidic laser processing equipment are set, and the cutting parameters include at least the rated power, wavelength and pulse frequency of the laser, the nozzle diameter of the microfluidic laser, the water pressure of the microfluidic laser and the coupling power. The micro-jets of the micro-jets in the micro-jets laser processing equipment are moved a distance of t+d+0.8×d from the growth surface of the diamond crystal toward the seed crystal surface. Then, the micro-jets laser is moved along the length of the diamond crystal to the outside of the diamond crystal and spaced a certain distance from the outer edge of the diamond crystal. The current point is set as the cutting origin, where t is the cutting thickness and d is the diameter of the micro-jets laser.

4. The method for slicing large-size diamond crystals according to claim 1, characterized in that, The laser in the microjets laser device is a green nanosecond pulsed laser with a rated power of 400W, an emitted laser wavelength of 532nm, and a pulse frequency of 10kHz. The cutting water pressure of the microjets laser device is greater than 500bar, and the coupling power at a jet length of 40mm is not less than 100W.

5. The method for slicing large-size diamond crystals according to claim 1, characterized in that, S4 includes: The microjets laser cuts from the first side to the second side along the length of the diamond crystal, starting from the cutting origin. Then, it moves a first preset distance along the direction from the seed crystal surface toward the growth surface, and then cuts in the opposite direction from the second side to the first side along the length. The trajectories of the two cuts overlap. Then, it continues to cut along the same trajectory until the cutting depth reaches the first preset depth, and then returns to the cutting origin.

6. The method for slicing large-size diamond crystals according to claim 5, characterized in that, S5 includes: The microjets laser cuts from the origin of the diamond crystal along the length of the crystal from the first side to the second side. Then, it moves a second preset distance along the direction from the seed crystal surface toward the growth surface, and then cuts back from the second side to the first side along the length of the crystal. The trajectories of the two cuts overlap. The cutting continues along the same trajectory until the cutting depth reaches the second preset depth, and then the laser returns to the origin of the crystal.

7. The method for slicing large-size diamond crystals according to claim 6, characterized in that, The first preset distance is 0.8d, the second preset distance is 0.5d; the first preset depth is 0.2h, the second preset depth is 0.4h, and the third preset depth is 0.5h, where h represents the width of the diamond crystal along the cutting direction.

8. The method for slicing large-size diamond crystals according to claim 1, characterized in that, S7 includes: The first tooling and the second tooling, together with the diamond crystal, are simultaneously rotated 180° along the center line of the first tooling, and steps S4 to S6 are repeated until the diamond crystal is completely cut through, forming a seed crystal fixed on the first tooling and a growth crystal fixed on the second tooling. The cutting surface of the seed crystal is planar, and the cutting surface of the growth crystal is stepped.

9. The method for slicing large-size diamond crystals according to any one of claims 1 to 8, characterized in that, S8 includes: The microjets laser is moved 0.8d along the cutting origin in the direction from the seed crystal surface toward the growth surface, and the moved position is redefined as the new cutting origin. The laser is then used to cut back and forth along the length direction to a depth of 0.5h from the new cutting origin. The second tooling is rotated 180°, and the cutting is repeated from the new cutting origin to the cutting start point until the slice is completed. The cutting surface of the diamond crystal is a flat surface, where d is the diameter of the microjets laser and h represents the width of the diamond crystal along the cutting direction.

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