Diamond laser slicing method and device

Abstract

The invention relates to the technical field of diamond processing, in particular to a diamond laser slicing method and device. The invention relates to a diamond laser slicing method. The method comprises the following steps: 1) utilizing a laser beam from 1t; 100 gt; the surface vertically enters the interior of the single crystal diamond, and a C-C bond is fractured by forming instant local high temperature so as to be carbonized to form graphite; (2) the laser beam is at the distance lt; 100 gt; the surface is at a certain depth and is scanned along the crystal orientation direction of # imgabs0 # or # imgabs1 #, and by controlling the position of a laser focal plane and the energy of the position, only modification points and a graphite layer are formed, or modification points are formed along lt; 111gt, 111gt; the surface-expanded cracks further form a crack expansion layer, and stress difference is generated between the crack expansion layer and the non-modified layer, so that the diamond layer is convenient to peel off. According to the method, arrangement and / or crack propagation of modified points can be accurately controlled, and stress distribution of a modified layer is optimized, so that high-precision diamond slicing is realized, and fragmentation and damage of a sample are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond processing, and particularly relates to a diamond laser slicing method and apparatus. Background Art

[0002] As the hardest material in nature, diamond is widely used in optical components, electronic devices, aerospace and other fields due to its excellent physical properties, including extremely high hardness, thermal conductivity and chemical corrosion resistance. In the past, silicon carbide (SiC) and gallium nitride (GaN) have been provided as semiconductor materials suitable for power devices to replace silicon (Si). Compared with these semiconductor materials, diamond semiconductors have a high dielectric breakdown electric field, a high power control index and the highest thermal conductivity, and thus have attracted attention as a next-generation material and are being researched and developed towards practical applications. However, due to the extremely high hardness and brittleness of diamond, traditional mechanical cutting methods are prone to cause diamond fragmentation during processing, and have low processing efficiency and large losses. Therefore, laser processing technology has become an effective alternative method for cutting diamond.

[0003] Existing traditional diamond slicing methods include laser ablation method and ion implantation method. Among them, the laser ablation method removes materials through surface ablation, with high processing efficiency, but has problems such as large notch loss and inapplicability to large sizes; the ion implantation method has low processing efficiency, small processing area and cumbersome steps.

[0004] The Chinese patent application for invention (Publication No.: CN115555743A, Publication Date: January 3, 2023) discloses a diamond substrate manufacturing method including: a step of disposing a laser condensing portion for condensing laser to face the upper surface of a single-crystal diamond block; a step of irradiating laser from the laser condensing portion toward the upper surface of the block to condense the laser inside the block, and at the same time relatively moving the laser condensing portion and the block two-dimensionally, so as to form a modified layer including graphite processing marks and cracks extending along the (111) plane around the processing marks from the upper surface to a specified depth in a partial area of the upper surface of the block along the (111) plane of the single-crystal diamond; and a step of spontaneously propagating cracking from the modified layer to the specified depth in the remaining area of the upper surface of the block to form a cracking surface.

[0005] Such as Figures 1-3As shown, the cleavage plane of single-crystal diamond is the <111> plane. In the patent CN115555743A, the surface of the diamond sample is the <111> plane. At this time, cracks are formed by machining and scanning along the <111> plane, and the crack propagation direction is the <111> crystal direction, perpendicular to the laser irradiation direction. In actual samples, due to the diamond crystal growth process, most single-crystal diamonds have the <100> crystal direction as the upper surface. At this time, if damage points are formed and cracks are generated, the cracks will propagate along the <111> plane. At this time, the cracks are not easy to connect, and a large damaged layer will be generated. The damaged layer of the modified particles and cracks needs to be removed in the subsequent grinding process. Therefore, a smaller damaged layer is required to reduce laser loss. The loss caused by the laser mainly focuses on the projection of the modified particles and cracks on the <011> plane and the <011> plane. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a diamond laser slicing method based on laser modified particle generation and crack control, which can precisely control the arrangement of modified particles and / or crack propagation, optimize the stress distribution of the modified layer, so as to achieve high-precision diamond slicing and avoid fragmentation and damage of the sample.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A diamond laser slicing method, which includes the following steps: 1) Use a laser beam to vertically enter the single-crystal diamond from the <100> plane, and break the C-C bond through the formation of an instant local high temperature to form graphite by carbonization; 2) The laser beam is at a certain depth from the <100> plane and scans along or the crystal direction, by controlling the position of the laser focal plane and the energy at this position, only form modified particles and graphite layer A, or form modified particles and cracks extending along the <111> plane, and then form a crack propagation layer B, generating a stress difference and / or forming cracks with the non-modified layer, facilitating the peeling of single-crystal diamond.

[0008] Preferably, by controlling the center distance L1 between adjacent modified particles on the same light beam path and the distance L2 between adjacent light beam paths, the damage during the laser processing is minimized, the stress distribution of the modified layer is uniform, and the removal amount of single-crystal diamond is reduced.

[0009] Preferably, when the laser forms modified particles in the single-crystal diamond without generating cracks, the values of the center distance L1 between adjacent modified particles and the distance L2 between the light beam paths are less than or equal to the diameter D1 of the modified particles along the <011> crystal direction, ensuring the connection between adjacent modified particles, forming a dense graphite layer A, and avoiding sample cracks or fragments.

[0010] Preferably, when the laser simultaneously forms modified points and cracks in single-crystal diamond, the center distance L1 between adjacent modified points is less than or equal to the crack propagation length L3, and the distance L2 between the beam paths is less than or equal to half of the diameter D2 of the modified points, so as to form a crack propagation layer B through the intersection of the graphite points and the cracks.

[0011] More preferably, the stress difference between the crack propagation layer B and the unmodified layer ensures uniform internal stress in the crack propagation layer B, enabling the peeling device to effectively peel the single-crystal diamond without generating fragments.

[0012] Furthermore, the present invention also discloses a diamond laser slicing device adopting the above method. The device includes a laser module, an optical module, a clamping module, and a displacement module. The laser module generates a laser beam, the optical module focuses the laser inside the sample, the clamping module is used to fix the single-crystal diamond, and the displacement module has the ability of three-dimensional movement in the X-Y-Z directions to control the relative position of the sample and the depth of the laser focal plane.

[0013] Preferably, the displacement module controls the focusing depth of the laser inside the single-crystal diamond through the Z-axis, and the X-axis and Y-axis control the planar movement of the sample to enable the laser beam to scan along the crystal orientation or other preset directions.

[0014] Preferably, by adjusting the spacing L1 between adjacent modified points on the beam path and the distance L2 between adjacent beam paths, uniform slicing of the single-crystal diamond by the laser is achieved, reducing damage and optimizing the stress distribution of the modified layer.

[0015] Preferably, the optical module includes an adjustable focusing device capable of real-time adjustment of the laser focal plane according to the thickness and crystal orientation of the single-crystal diamond.

[0016] Preferably, the laser parameters generated by the laser module can be dynamically adjusted according to the processing requirements to ensure the generation of modified points or cracks at different slicing depths and control the diameter of the modified points and the crack length.

[0017] Due to the adoption of the above technical solutions, the present invention can significantly improve the precision and efficiency of diamond slicing and effectively reduce material damage. Its main technical effects include the following points: 1. Improve cutting accuracy: By controlling the laser focusing depth and the energy of the laser beam, the present invention can accurately generate modified points and cracks inside the diamond. According to actual requirements, local graphitization regions or cracks can be formed inside the single-crystal diamond, so that high-precision material removal can be achieved during the cutting process, the slicing surface is flat, and the error is extremely small.

[0018] 2. Reduce material loss and thermal damage: By optimizing the arrangement of modified particles in the present invention, the stress of the graphite layer generated during laser processing is evenly distributed, avoiding the problem of crack propagation caused by excessive thermal stress during traditional laser cutting. Especially after forming a dense graphite layer, peeling is carried out using the stress difference between the graphite layer and the unmodified area, greatly reducing material loss and thermal damage while ensuring a smooth cutting surface without debris.

[0019] 3. Improve slicing efficiency: Through the coordinated action of the laser module, optical module, clamping module, and displacement module in the laser device of the present invention, rapid and stable scanning of the laser can be achieved, precisely controlling the generation of modified particles and the propagation range of cracks, effectively improving the automation degree during the cutting process, and thus greatly enhancing the processing efficiency.

[0020] 4. Improve slicing quality: In terms of controlling modified particles and crack propagation, by adjusting the center distance L1 between adjacent modified particles and the distance L2 between adjacent beam paths in the present invention, the generation of a uniform and dense graphite layer A and a crack propagation layer B is achieved, avoiding quality problems such as cracks and debris caused by uneven stress. The stress of the modified layer is evenly distributed, ensuring stable stress release during the slicing process and reducing the grinding and trimming work in subsequent cutting steps.

[0021] 5. Controllable crack propagation: During the process of generating modified particles by laser in the present invention, the generation and propagation of cracks can be precisely controlled. By reasonably regulating parameters such as L1, L2, D1, and D2, the cracks only extend within a preset range, avoiding excessive crack propagation from affecting the slicing quality, thus ensuring that the cutting result meets the requirements of precision machining.

[0022] 6. Wide applicability: The present invention is applicable to the slicing processing of single-crystal diamond with various different sizes and thicknesses, especially suitable for high-end application scenarios with extremely high requirements for cutting accuracy and surface quality, further expanding the application field of diamond laser slicing technology.

[0023] In summary, through the precise control of modified particles and cracks during the laser slicing process, the present invention not only improves the cutting accuracy, reduces material loss, but also significantly enhances the slicing efficiency and improves the slicing quality, providing an efficient and stable solution for the high-end diamond processing field. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the cleavage plane of single-crystal diamond.

[0025] Figure 2 It is a schematic diagram of the projection of modified particles and cracks on the <011> plane.

[0026] Figure 3 It is for modified particles and cracks in Schematic diagram of the projection on the plane.

[0027] Figure 4 For the case where the laser generates modified particles inside the diamond without generating cracks, the projection of the modified particles and cracks on the <011> plane or Schematic diagram of the projection on the plane.

[0028] Figure 5 Schematic diagram of the projection of the modified particles and cracks on the <011> plane when the laser generates modified particles and cracks inside the diamond.

[0029] Figure 6 For the case where the laser generates modified particles and cracks inside the diamond, the projection of the modified particles and cracks on the Schematic diagram of the projection on the plane.

[0030] Figure 7 Schematic diagram of the structure of the device of the present invention.

[0031] Figure 8 Schematic diagram of the laser beam scanning. Detailed implementation manners

[0032] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0033] Embodiment 1: The case where the laser generates modified particles inside the diamond without generating cracks In this embodiment, the laser is vertically incident into the single-crystal diamond through the plane. By precisely controlling the laser energy and the focusing depth, a local high temperature is formed inside the diamond by the laser, thereby causing the breakage of C-C bonds and generating modified particles. At this time, the control of the laser energy and its focal position ensures that only modified particles are formed inside the diamond without generating cracks.

[0034] 1. Setting of laser parameters: Select appropriate laser power, pulse duration, and focusing depth to ensure that the laser energy is concentrated at a specific position inside the diamond. The focus of the laser is adjusted to a certain depth Z1 inside the diamond, and at this depth position, the laser forms modified particles inside the single-crystal diamond.

[0035] 2. Formation and control of modified particles: The action of the laser raises the local temperature inside the diamond to a level sufficient to break the C-C bonds, but the energy is controlled so that the range of heat diffusion is limited, only forming modified particles without causing cracks. The diameter of the modified particles along the <011> crystal direction is D1. By controlling the distance L1 between the centers of adjacent modified particles and the distance L2 between adjacent beam paths, the uniform distribution of the modified particles is ensured, forming a dense graphite layer A.

[0036] 3. Spacing of Modified Particles and Formation of Graphite Layer A: The center distance L1 between adjacent modified particles on the same path is less than or equal to the diameter D1 of the modified particles, expressed by the following relationship: L1 = L2 ≤ D1; ensuring that adjacent modified particles intersect to form a sufficiently dense graphite layer A. The internal stress of graphite layer A is uniformly distributed, enabling the smooth peeling of the diamond layer during subsequent peeling operations without causing cracks or fragmentation.

[0037] 4. Laser Scanning Process: The laser beam scans at a certain depth from the <100> plane and along or the crystal direction. Point-by-point light emission is carried out at the set spacing L1 on each beam path, ensuring the uniform generation of modified particles of the laser inside the diamond. The interval L2 between adjacent beam paths ensures the neat arrangement of the modified particles, ultimately forming graphite layer A. Since no cracks are generated, the modified layer is peeled only through the stress difference between the graphitized area and the non-modified area.

[0038] The following conducts a detailed description of this embodiment through experiments.

[0039] Experimental Setup: Laser Power: By adjusting the laser power, the generation of modified particles is ensured without causing cracks.

[0040] Focal Plane Depth: The laser focus is set at the internal depth Z1 of the single-crystal diamond.

[0041] Diameter of Modified Particles: D1 is the diameter of the modified particles along the <100> crystal direction, and L1 and L2 control the distance between adjacent modified particles.

[0042]

[0043] Example 2: The Case of Laser Generating Modified Particles and Cracks Inside the Diamond In this embodiment, the laser is also perpendicularly incident into the single-crystal diamond. By adjusting the laser energy and focusing depth, the laser not only forms modified particles inside the diamond but also initiates the generation and propagation of cracks. The cracks propagate along the crystal direction and intersect with the modified particles to form a crack propagation layer B.

[0044] 1. Setting of Laser Parameters: The laser energy is set relatively high, which is sufficient to break the C-C bond and initiate the generation of cracks. The focus of the laser is adjusted to a certain depth Z2 inside the diamond. At this depth, the laser generates modified particles inside the single-crystal diamond and produces cracks along the <111> plane. Let D1 be the diameter of the modified particle along the <011> crystal direction, D2 be the diameter of the modified particle along the <100> crystal direction, L1 be the distance between the centers of adjacent modified particles on the same light beam path, L2 be the distance between adjacent light beam paths, L3 be the crack propagation length of the modified particle along the crystal direction, and α be the angle between the crack formed along the cleavage plane and the plane.

[0045] 2. Formation of modified particles and cracks: The laser action not only generates modified particles but also initiates the crack to propagate along the <111> crystal direction. The diameter of the modified particle is D1, and the crack propagation range is controlled by the crack propagation length L3 of the modified particle. By adjusting the distance L1 between the centers of adjacent modified particles, making L1 less than or equal to the crack propagation length L3, it is ensured that the cracks intersect to form a uniform crack propagation layer B.

[0046] 3. Control of the intersection of modified particles and cracks: The relationship between the distance L2 between adjacent light beam paths on the laser beam path and the diameter D2 along the <100> crystal direction is: 2*L2 ≤ D2 / tan(α); since the cleavage plane is the <111> crystal direction, so α = 45°, at this time L2 ≤ D2 / 2. The crack extension direction propagates along the crystal direction and intersects with adjacent modified particles, thereby forming a crack propagation layer B and preventing the crack from overextending.

[0047] 4. Laser scanning process: The laser beam scans at a certain depth from the <100> plane and along the or crystal direction. The laser beam generates modified particles point by point inside the diamond, and at the same time initiates cracks. The modified particles and cracks intersect on the light beam path. The interval L2 between adjacent laser scanning lines ensures the uniform distribution of cracks and modified particles, and finally forms a crack propagation layer B. The crack propagation layer B forms a stress difference between the crack propagation layer and the non-modified layer through the intertwined structure of the cracks, effectively avoiding the generation of diamond fragments.

[0048] In this embodiment, due to the interaction between the cracks and the modified particles, efficient peeling can be achieved, and it is ensured that the stress distribution of the crack propagation layer B is uniform, effectively improving the slicing quality and accuracy. The following conducts a detailed description of this embodiment through experiments.

[0049] Experimental setup: Laser power: The laser power is increased to generate cracks.

[0050] Focal plane depth: The laser focus is set at the internal depth Z2 of single-crystal diamond.

[0051] Modification point and crack control: D1, D2, L1, L2, and L3 are key parameters to control the intersection of crack propagation and modification points.

[0052]

[0053] As Figure 7 shown, a diamond laser slicing device of the present invention has a laser module, an optical module, a clamping module, and a displacement module; wherein: the laser module generates laser with specific parameters; the optical module transmits the laser and focuses it at the objective lens; the clamping module fixes the sample; the displacement module has the ability of three-dimensional movement in the X-Y-Z directions. The Z-axis can drive the sample to move up and down to adjust the focusing depth of the laser inside the sample, and the X and Y axes realize the relative movement between the sample and the laser.

[0054] The ingot uses the <100> plane as the processing upper surface; before processing, observe the modification points and cracks of the laser in single-crystal diamond under specific focusing depth, energy and other parameters. For the modification points, observe and record the diameter D1 of the modification point along the <011> crystal direction and the diameter D2 of the modification point along the <100> crystal direction, and observe and record whether cracks are generated under this parameter and the expansion length L3 of the crack along the crystal direction.

[0055] During processing, the laser beam scans along a certain depth Z1 from the <100> plane and along the crystal direction or crystal direction, emits laser light at the point spacing of L1 along the same path, and makes adjacent laser scan lines parallel to each other with a line interval of L2.

[0056] For the case where modification points are generated and cracks are not generated, it is necessary to satisfy that the distance L1 between the centers of adjacent modification points on the same light beam path and the distance L2 between adjacent light beam paths are less than or equal to the diameter D1 of the modification point along the <011> crystal direction for processing; For the case where modification points are generated and cracks are generated, it is necessary that the distance L1 between the centers of adjacent modification points on the same light beam path is less than or equal to the crack expansion length L3 of the modification point along the crystal direction, and the distance L2 between adjacent light beam paths is less than or equal to half of the diameter D2 along the <100> crystal direction for processing; Use the above method to scan repeatedly until all areas of the ingot turn grayish-black, ensuring that the stress distribution of the modified layer of the sample is uniform and can be peeled off.

[0057] The foregoing is a description of embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A diamond laser slicing method, characterized in that: The method comprises the following steps: 1) Using laser beam from <100> The surface is incident vertically into the interior of the single crystal diamond, and the CC bonds are broken by forming an instantaneous local high temperature, which then carbonizes to form graphite. 2) Laser beam at distance <100> A certain depth along the surface or The laser is scanned in the crystal direction, and the position of the laser focal plane and the energy at that position are controlled to form only the modified point and the graphite layer A, or to form the modified point and the graphite layer along the crystal direction. <111> The cracks propagate from the surface, thereby forming a crack propagation layer B, which generates a stress difference and / or forms cracks with the non-modified layer, making it easier to peel off the single crystal diamond.

2. The diamond laser slicing method according to claim 1, characterized in that: By controlling the center distance L1 of adjacent modified points on the same beam path and the distance L2 between adjacent beam paths, the damage during laser processing is minimized, the stress distribution of the modified layer is uniform, and the removal amount of single crystal diamond is reduced.

3. The diamond laser slicing method according to claim 2, characterized in that: When the laser forms a modified point in the single crystal diamond without generating cracks, the value of the distance L1 between the centers of adjacent modified points and the distance L2 between the beam paths is less than or equal to the distance along the modified point. <011> The diameter D1 of the crystal direction ensures the connection between adjacent modified points, forming a dense graphite layer A and avoiding the generation of cracks or fragments in the sample.

4. The diamond laser slicing method according to claim 2, characterized in that: When the laser forms modified points and cracks in single crystal diamond at the same time, the center distance L1 between adjacent modified points is less than or equal to the crack extension length L3, and the distance L2 between the beam paths is less than or equal to half of the modified point diameter D2, thereby forming a crack extension layer B through the intersection of the graphite point and the crack.

5. The diamond laser slicing method according to claim 4, characterized in that: The stress difference between the crack extension layer B and the non-modified layer ensures that the internal stress of the crack extension layer B is uniform, so that the stripping device can effectively strip the single crystal diamond without generating fragments.

6. A diamond laser slicing device using the method according to any one of claims 1 to 5, characterized in that: The device comprises a laser module, an optical module, a clamping module and a displacement module. The laser module generates a laser beam, the optical module focuses the laser inside the sample, the clamping module is used to fix the single crystal diamond, and the displacement module has XYZ three-dimensional movement capability to control the relative position of the sample and the depth of the laser focal plane.

7. The diamond laser slicing device according to claim 6, characterized in that: The displacement module controls the focusing depth of the laser inside the single crystal diamond through the Z axis, and controls the planar movement of the sample through the X and Y axes to achieve scanning of the laser beam along the crystal direction or other preset directions.

8. The diamond laser slicing device according to claim 6, characterized in that: By adjusting the distance L1 between adjacent modified points on the beam path and the distance L2 between adjacent beam paths, uniform slicing of single crystal diamond by laser can be achieved, damage can be reduced, and stress distribution of the modified layer can be optimized.

9. The diamond laser slicing device according to claim 6, characterized in that: The optical module includes an adjustable focusing device, which can adjust the laser focal plane in real time according to the thickness and crystal orientation of the single crystal diamond.

10. The diamond laser slicing device according to claim 6, characterized in that: The laser parameters generated by the laser module can be dynamically adjusted according to processing requirements to ensure the generation of modified points or cracks at different slicing depths and control the diameter of the modified points and the crack length.

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