A method for slicing large-size diamond crystals

Abstract

The present invention discloses a slicing method for a large-size diamond crystal, comprising: fixing the seed crystal surface of the diamond crystal on a first tool, and adjusting the angle between the microjet laser and the growth surface; setting cutting parameters and determining the cutting origin; fixing the growth surface on a second tool; reciprocatingly cutting the diamond crystal along a first rectangular cutting trajectory until the cutting depth reaches a first preset depth; reciprocatingly cutting the diamond crystal along a second rectangular cutting trajectory until the cutting depth reaches a second preset depth; reciprocatingly 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 center line of the first tool and repeating the above steps until they are completely cut off; and continuing to cut the stepped cutting surface to form a flat cutting surface. The present invention cuts layer by layer by means of rectangular expansion and flipping cutting, thereby avoiding the influence of water accumulation in the cutting groove on the power of the microjet laser and improving the cutting efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of micro jet laser processing, and in particular relates to a slicing method of a large-size diamond crystal. Background Art

[0002] Single crystal diamond has an ultra-wide bandgap, low dielectric constant, high breakdown voltage, high intrinsic electron and hole mobility, and excellent radiation resistance. It is the best known wide bandgap high-temperature semiconductor material. However, a major challenge facing the current single crystal diamond preparation field is how to achieve the goal of preparing single crystal diamond materials with inch-level ultra-large wafer area under chemical vapor deposition (CVD) technology. Breaking through this technical bottleneck is crucial to promoting the development of the entire industry. At the same time, in the CVD preparation process, depending on the type of substrate used, the growth mode of diamond can be divided into two major paths: heteroepitaxial and homoepitaxial. The mainstream inch-level large-size single crystal diamond materials on the market currently rely on the successful application of heteroepitaxial technology, which to a certain extent limits the rapid development of homoepitaxial devices, making their exploration in the application field relatively lagging behind 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] Microjet laser technology is widely used in precision machining due to its clean cutting path, no thermal stress, and narrow cutting path. For diamond slicing, microjet laser processing technology is a good choice. However, during the slicing process, as the cutting depth increases, water that cannot be discharged in time often accumulates in the slit. This water will destroy the total reflection effect of the microjet laser, resulting in limited cutting depth. The larger the cutting size, the more serious the water accumulation, which also limits the application of microjet laser in large-scale diamond slicing technology. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a slicing method of a large-sized diamond crystal. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] The present invention provides a method for slicing a large-size diamond crystal, comprising:

[0006] S1: fixing the seed crystal surface of the diamond crystal to be cut on the first fixture, and adjusting the angle between the microjet laser and the growth surface of the diamond crystal, wherein the diamond crystal includes the seed crystal surface and the growth surface opposite to and parallel to the seed crystal surface;

[0007] S2: Setting the cutting parameters of the microjet laser processing equipment and determining the position of the cutting origin;

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

[0009] S4: reciprocatingly cutting the diamond crystal from the cutting origin along a first rectangular cutting track until the cutting depth reaches a first preset depth and then returns to the cutting origin;

[0010] S5: reciprocatingly cutting the diamond crystal from the cutting origin along a second rectangular cutting track until the cutting depth reaches a second preset depth and then returns to the cutting origin;

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

[0012] S7: turning the first tool and the second tool together with the diamond crystal by 180 degrees along the center line of the first tool at the same time and repeating steps S4 to S6 until the diamond crystal is completely cut off, forming a smooth and stepless cutting surface fixed on the first tool and a stepped cutting surface fixed on the second tool;

[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, the S1 includes:

[0015] The seed crystal face of the diamond crystal is fixed on the first fixture by adsorption or bonding, and the seed crystal face is perpendicular to the center line of the first fixture, and the first fixture can be freely turned along its center line, wherein the diamond crystal includes a seed crystal face and a growth face opposite to and parallel to the seed crystal face, and the seed crystal face and the growth face are both faces surrounded by the length direction and the width direction of the diamond crystal;

[0016] The angle between the microjet laser formed by the microjet laser processing equipment and the growth surface of the diamond crystal is adjusted so that the microjet laser is parallel to the growth surface.

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

[0018] Setting cutting parameters of the microjet laser processing equipment, wherein the cutting parameters include at least the rated power, wavelength and pulse frequency of the laser, the nozzle diameter of the microjet laser, the water pressure and coupling power of the microjet laser;

[0019] Move the microjet laser of the microjet laser processing equipment from the growth surface of the diamond crystal to the seed crystal surface by a distance of t+d+0.8×d, then move the microjet laser along the length direction of the diamond crystal to the outside of the diamond crystal and keep a certain distance from the outer edge of the diamond crystal, and set the current point as the cutting origin, wherein t is the cutting thickness and d is the diameter of the microjet laser.

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

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

[0022] The microjet laser starts from the cutting origin and cuts from the first side to the second side along the length direction of the diamond crystal, then moves a first preset distance along the seed crystal surface toward the growth surface, and then cuts in reverse from the second side to the first side along the length direction, and the two cutting trajectories overlap, and then continues cutting 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, the S5 includes:

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

[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, the S7 includes:

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

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

[0029] The microjet laser is moved along the cutting origin along the direction of the seed crystal surface toward the growth surface by a distance of 0.8d, and the moved position is redefined as a new cutting origin, and the cutting depth is reciprocated along the length direction with the new cutting origin as the starting point for 0.5h;

[0030] The second tool is turned over 180°, and reciprocating cutting is performed with the new cutting origin as the cutting starting point until slicing is completed. The cutting surface of the diamond crystal is a flat surface, wherein d is the diameter of the microjet laser, and h represents the width of the diamond crystal along the cutting direction.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The large-size diamond slicing process method of the present invention performs deep cutting layer by layer by means of rectangular expansion and flip cutting, thereby avoiding the influence of water accumulation in the cutting groove on the microjet laser power, thereby realizing effective cutting of large-size diamond crystals; at the same time, the steps formed by cutting layer by layer are cut and trimmed, so that the seed crystal surface and the growth surface after slicing have good cutting surfaces, reducing the time and production cost of later wafer polishing, ensuring the slicing quality, and improving the slicing efficiency.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of a method for slicing a large-size diamond crystal provided by an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the size direction of a diamond crystal to be cut provided by an embodiment of the present invention;

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

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

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

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

[0040] Figure 7 This is a schematic diagram of a slice with one side cut completed provided by an embodiment of the present invention;

[0041] Figure 8 This is a schematic diagram of a slice after both sides have been cut after turning over, provided by an embodiment of the present invention;

[0042] Fig. 9 This is a schematic diagram of a step surface repair provided by an embodiment of the present invention;

[0043] Fig.10 It is a schematic diagram after slicing is completed provided by an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1-diamond crystal; 2-first tooling; 3-second tooling; 4-microjet laser; 5-seed crystal; 6-growing crystal. DETAILED DESCRIPTION

[0046] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, a slicing method of a large-size diamond crystal proposed in accordance with the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0047] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.

[0048] It should be noted that, in this article, relational terms such as first and second, etc. 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 "include", "comprise" or any other variants are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the statement "including one..." do not exclude the existence of other identical elements in the article or device including the elements.

[0049] Embodiment 1

[0050] See also Figure 1 , Figure 1 This is a flow chart of a slicing method of a large-sized diamond crystal provided by an embodiment of the present invention. The slicing method specifically includes the following steps:

[0051] S1: Fixing the seed crystal surface of the diamond crystal 1 to be cut on the first tool 2, and adjusting the angle between the microjet laser 4 and the growth surface of the diamond crystal 1.

[0052] See also Figure 2 , Figure 2 1 is a schematic diagram of the size direction of a diamond crystal to be cut according to an embodiment of the present invention. The diamond crystal 1 is in the shape of a cuboid, with a length of L, a width of h, and a thickness of T. The length direction is parallel to the X-axis direction, the width direction is parallel to the Y-axis direction, and the thickness direction is parallel to the Z-axis direction. The microjet laser processing equipment is located above the diamond crystal 1, and the diamond crystal 1 is cut into different thicknesses using a microjet laser. The diamond crystal 1 has a seed crystal face and a growth face opposite to and parallel to the seed crystal face, and both the seed crystal face and the growth face are faces surrounded by the length direction and the width direction.

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

[0054] Adjust the angle between the microjet laser 4 and the growth surface of the diamond crystal 1 so that the microjet laser 4 is completely parallel to the growth surface of the diamond crystal 1, such as Figure 4 In addition, the first tool 2 can be freely turned over along its own center line.

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

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

[0057] In this embodiment, the laser of the micro-jet laser processing equipment adopts a green nanosecond pulse laser with a rated power of 400W, a wavelength of the emitted laser of 532nm, a pulse frequency of 10KHZ, a nozzle of 60μm diameter, a water pressure greater than 500bar, and a pure water resistivity greater than 15ΩM / cm 3 , the helium flow rate is not less than 0.1L / min, and the coupling power of the microjet laser at a jet length of 40mm is not less than 100W.

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

[0059] See also Figure 5 , Figure 5 Schematic diagram of a process for determining the cutting origin position provided by an embodiment of the present invention. Figure 5 The microjet laser 4 is placed on the growth surface of the diamond crystal 1 (shown as the dotted circle on the far right) and moves (t+d+0.8×d) mm from the growth surface to the seed crystal surface. The microjet laser 4 is then moved 2 mm outside the diamond crystal along the length direction of the diamond crystal 1 and this point is set as the cutting origin ( Figure 5 ).

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

[0061] Specifically, the growth surface of the diamond crystal 1 to be cut is adsorbed on the second fixture 3 by adsorption or pasting, so that both sides of the diamond crystal 1 are completely fixed, the center line of the first fixture 2 is in the same straight line with the center line of the second fixture 3, and the center line of the first fixture 2 is used as the adjustment reference. In addition, the second fixture 3 can be freely flipped along its own center line.

[0062] S4: Starting from the cutting origin, reciprocatingly cutting the diamond crystal along the first rectangular cutting track until the cutting depth reaches a first preset depth and then returns to the cutting origin.

[0063] When starting to cut, the microjet laser 4 starts from the cutting origin and cuts from the first side to the second side along the length direction (X-axis direction) of the diamond crystal 1, then moves a first preset distance toward the growth surface along the thickness direction, and then cuts from the second side to the first side in the length direction in reverse, and there is a partial overlap in the trajectories of the two cuttings, and then continues cutting along the same trajectory until the cutting depth reaches the first preset depth and then returns to the cutting origin.

[0064] See also Figure 6 , Figure 6Schematic diagram of a rectangular cutting track provided by an embodiment of the present invention. In a specific embodiment, when cutting, a (L+4) mm length (such as Figure 6 The cutting point is moved from the initial cutting origin (2 mm away from the first side of the diamond crystal 1 along the length direction of the diamond crystal 1) to 2 mm away from the second side of the diamond crystal 1; and then moved (0.8d) mm along the direction of the seed crystal facing the growth surface (as shown by the solid line along the X-axis direction in (a)). Figure 6 The Z-axis direction is shown by the short solid line in (a)); then the length is reversely cut along the length direction (L+4) mm (as shown in FIG. Figure 6 The dotted line in the X-axis direction in (a) of FIG. 1 forms a cutting knife by cutting twice in the length direction, and the cutting knife amount is (0.2d) mm (that is, the track of each cutting has a certain width, which is equal to the diameter d of the microjet laser 4, and there is an overlap of (0.2d) mm between the two cuttings), and then returns to the cutting origin. A rectangular cutting track with a length of (L+4) mm and a width of (0.8d) mm is formed, and the width of the cutting slit formed is (1.8d) mm (as shown in FIG. 1 ). Figure 6 As shown in (b) in the figure, the cutting track is cyclically cut to a depth of (0.2h) mm and then the cutting track is returned to the origin; since the cutting slit is enlarged, the accumulated water in the cutting process is effectively discharged, thereby improving the cutting efficiency; wherein L is the crystal length, d is the microjet diameter, and h is the width of the diamond crystal 1, i.e., the total depth of the slice. Preferably, the pressure formed by the cutting track is not less than 0.1d.

[0065] S5: Starting from the cutting origin, reciprocatingly cutting the diamond crystal along the second rectangular cutting track until the cutting depth reaches the second preset depth and then returns to the cutting origin.

[0066] The microjet laser starts from the cutting origin and cuts from the first side to the second side along the length direction of the diamond crystal, then moves a second preset distance in the direction from the seed crystal surface to the growth surface, and then cuts from the second side to the first side in the length direction in the reverse direction, and the two cutting trajectories overlap, and then continues cutting with the same trajectory until the cutting depth reaches the second preset depth and then returns to the cutting origin. Preferably, the pressure formed by the cutting trajectory is not less than 0.1d.

[0067] Similarly, in this embodiment, the cutting origin is continued to be used to cut a length of (L+4) mm along the length direction of the crystal, then move (0.5d) mm along the seed crystal surface toward the growth surface, and then cut a length of (L+4) mm in the reverse direction along the length direction. The two length-direction cuttings form a pressure cutter with a pressure cutter amount of (0.5d) mm, and then return to the cutting origin; a rectangular cutting track with a length of (L+4) mm and a width of (0.5d) mm is formed. The cutting seam width formed by this track is (1.5d) mm. This track is narrower than the previous track by (0.3d) mm, and the track is cycled to cut to a depth of (0.4h) mm before returning to the origin.

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

[0069] Specifically, the cutting origin is used to cut (L+4) mm along the length direction of the crystal to a depth of (0.5h) mm. The cutting state at this time is as follows: Figure 7 As shown; in this embodiment, the depth is measured using a 0.06mm feeler gauge.

[0070] S7: Flip the first tooling and the second tooling together 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, step-free cutting surface fixed on the first tooling and a stepped cutting surface fixed on the second tooling.

[0071] Specifically, the first tool 2 and the second tool 3 together with the diamond crystal are simultaneously turned 180° along the axis of the first tool 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 tool 2, the growth crystal 6 is fixed on the second tool 3, and the cutting surface of the seed crystal 5 is smooth without steps, and the cutting surface of the growth crystal 6 is step-shaped, as shown in FIG. Figure 8 shown.

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

[0073] Specifically, the microjet laser is moved along the current cutting origin along the direction from the seed crystal surface to the growth surface by (0.8d) mm, and the current point is redefined as a new cutting origin. The new cutting origin is used as the starting point, and the cutting is repeated along the length direction with a length of (L+4) mm and a depth of (0.5h) mm. Fig. 9 shown.

[0074] Then, the second tool is turned over 180°, and the grown crystal is turned over 180° accordingly. The new cutting origin is used as the cutting starting point, and the cutting length (L+4) mm is cut back and forth until the slicing is completed. The cutting surface of the diamond crystal is a flat surface, such as Fig.10 As shown, d is the diameter of the microjet laser, h represents the width of the diamond crystal along the cutting direction, and L represents the length of the diamond crystal.

[0075] Embodiment 2

[0076] Based on the first embodiment, this embodiment proposes another slicing method for large-sized diamond crystals. The diamond crystal to be cut in this embodiment adopts a crystal of 50 (length) × 50 (width) × 1.1 (thickness) mm; the planned slicing thickness t = 0.5 mm, and the crystal is divided into two pieces. The slicing method of this embodiment includes:

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

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

[0079] The angle between the microjet laser 4 and the growth surface of the diamond crystal 1 is adjusted so that the microjet laser 4 and the growth surface of the diamond crystal 1 are completely parallel and the diamond crystal 1 and the center line of the first tooling 2 are completely perpendicular.

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

[0081] Specifically, the laser of the microjet laser equipment adopts a green light nanosecond pulse laser with a rated power of 400W, a wavelength of the emitted laser of 532nm, a pulse frequency of 10KHZ, and a jet nozzle with a diameter of 60μm, that is, d=0.06mm; the microjet laser 4 is 6mm away from the surface processing position of the diamond crystal 1, 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 30mm.

[0082] The microjet laser 4 is placed against the growth surface of the diamond crystal 1 and moved 0.608 mm toward the seed crystal surface. The microjet 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 on the second tool 3.

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

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

[0086] When cutting, first cut 54mm in length along the length direction of the diamond crystal 1, then move 0.048mm along the growth surface direction, and then cut 54mm in length in the reverse direction. The two length-direction cuttings form a knife pressure (track overlap), the knife pressure amount is 0.012mm, and then return to the cutting origin to form a rectangular cutting track with a length of 54mm and a width of 0.048mm. The cutting width formed by the rectangular cutting track is 0.108mm, and the rectangular cutting track is cyclically cut to a depth of 10mm and then returns to the cutting origin; since the cutting seam is enlarged to 0.108mm, the accumulated water in the cutting process is effectively discharged, thereby improving the cutting efficiency.

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

[0088] Specifically, continue to cut 54mm in length along the length direction of the diamond crystal 1 from the cutting origin, then move 0.03mm along the growth surface direction, and then cut 54mm in length in the reverse direction. The two length-direction cuttings form a pressing knife (the tracks overlap), and the pressing amount is 0.03mm. Then return to the cutting origin to form a rectangular cutting track with a length of 54mm and a width of 0.03mm. The cutting width formed by this track is 0.09mm, which is 0.018mm narrower than the previous track. When the track is cut in a cycle to a depth of 20mm, it returns to the origin.

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

[0090] Specifically, the cutting origin is used to cut 54 mm along the length direction of the diamond crystal 1 to a depth of 25 mm. At this time, the crystal cut is as follows: Figure 7 As shown; the cutting depth in the above steps is measured using a 0.06mm feeler gauge.

[0091] Step 7: Turn the first tool 2 and the second tool 3 together 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 tool 2, and the growth crystal 6 is fixed on the second tool 3, and the cutting surface of the seed crystal 5 is smooth without steps, and the cutting surface of the growth crystal 6 is in the shape of steps. At this time, the cutting seam of the diamond crystal 1 is as follows: Figure 8 shown.

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

[0093] Specifically, the microjet laser 4 is moved 0.048 mm along the cutting origin toward the direction of the growing crystal and redefined as a new cutting origin. The new cutting origin is used to reciprocate and cut 25 mm deep along the length direction of the diamond crystal 1 with a length of 54 mm. Subsequently, the second tooling 3 is flipped 180°, and the growing crystal is flipped 180° accordingly. The new cutting origin is used as the cutting starting point to continue cutting with a length of 54 mm. Reciprocating cutting is performed until the slicing is completed. At this time, the surface of the growing crystal is flattened and the cut surface of the crystal is flat.

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

[0095] The large-size diamond slicing process method of the present invention performs deep cutting layer by layer by means of rectangular expansion and flip cutting, thereby avoiding the influence of water accumulation in the cutting path on the power in the depth direction of the jet, thereby realizing effective cutting of large-size diamond crystals; at the same time, the steps formed by cutting layer by layer are cut and trimmed, so that the seed crystal surface and the growth surface after slicing have good cutting surfaces, reducing the time and production cost of later wafer polishing, ensuring the slicing quality, and improving the slicing efficiency.

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

[0097] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0098] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for slicing large-size diamond crystals, characterized in that: include: S1: fixing the seed crystal surface of the diamond crystal to be cut on the first tooling, and adjusting the angle between the microjet laser and the growth surface of the diamond crystal, wherein the diamond crystal comprises a seed crystal surface and a growth surface opposite to and parallel to the seed crystal surface, wherein both the seed crystal surface and the growth surface are surfaces enclosed by the length direction and the width direction of the diamond crystal; S2: Setting cutting parameters of the micro-jet laser processing equipment and determining the position of the cutting origin, specifically, moving the micro-jet laser of the micro-jet laser processing equipment from the growth surface of the diamond crystal to the seed crystal surface by a distance of t+d+0.8×d, then moving the micro-jet laser along the length direction of the diamond crystal to the outside of the diamond crystal and being spaced a certain distance from the outer edge of the diamond crystal, setting the current point as the cutting origin, wherein t is the cutting thickness, and d is the diameter of the micro-jet laser; S3: fixing the growth surface of the diamond crystal on a second tooling, wherein the center line of the first tooling and the center line of the second tooling are in the same straight line; S4: reciprocatingly cutting the diamond crystal from the cutting origin along a first rectangular cutting track until the cutting depth reaches a first preset depth and then returns to the cutting origin; S5: reciprocatingly cutting the diamond crystal from the cutting origin along a second rectangular cutting track until the cutting depth reaches a second preset depth and then returns to the cutting origin; S6: Starting from the cutting origin, cutting back and forth along the length direction of the diamond crystal to a third preset depth; S7: turning the first tool and the second tool together with the diamond crystal by 180 degrees along the center line of the first tool at the same time and repeating steps S4 to S6 until the diamond crystal is completely cut off, forming a smooth and stepless cutting surface fixed on the first tool and a stepped cutting surface fixed on the second tool; S8: Continue cutting the stepped cutting surface fixed on the second tooling to form a flat cutting surface; Wherein, the S4 includes: The microjet laser starts from the cutting origin and cuts from the first side to the second side along the length direction of the diamond crystal, then moves a first preset distance along the seed crystal surface toward the growth surface, and then cuts from the second side to the first side in the length direction in the reverse direction, and the two cutting trajectories overlap, and then continues cutting along the same trajectory until the cutting depth reaches the first preset depth and then returns to the cutting origin; The S5 includes: The microjet laser starts from the cutting origin and cuts from the first side to the second side along the length direction of the diamond crystal, then moves a second preset distance along the seed crystal surface toward the growth surface, and then cuts from the second side to the first side in the length direction in the reverse direction, and the two cutting trajectories overlap, and then continues cutting along the same trajectory until the cutting depth reaches the second preset depth and then returns to the cutting origin; 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.

2. The method for slicing a large-size diamond crystal according to claim 1, characterized in that: The S1 includes: Fixing the seed crystal surface of the diamond crystal on the first fixture by adsorption or bonding, and making the seed crystal surface perpendicular to the center line of the first fixture, and the first fixture can be freely turned along its center line; The angle between the microjet laser formed by the microjet laser processing equipment and the growth surface of the diamond crystal is adjusted so that the microjet laser is parallel to the growth surface.

3. The method for slicing a large-size diamond crystal according to claim 1, characterized in that: The S2 further includes: The cutting parameters of the microjet laser processing equipment are set, and the cutting parameters at least include the rated power, wavelength and pulse frequency of the laser, the nozzle diameter of the microjet laser, the water pressure and coupling power of the microjet laser.

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

5. The method for slicing a large-size diamond crystal according to any one of claims 1 to 4, characterized in that: The S8 includes: The microjet laser is moved from the cutting origin along the direction of the seed crystal surface toward the growth surface by a distance of 0.8d, and the moved position is redefined as a new cutting origin, and the cutting is repeated along the length direction with a depth of 0.5h starting from the new cutting origin; The second tool is turned over 180 degrees, and reciprocating cutting is performed with the new cutting origin as the cutting starting point until the slicing is completed, and the cutting surface of the diamond crystal is a flat surface.

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