A method of laser cutting a silicon ingot

Abstract

The application relates to the technical field of semiconductor production and manufacturing, and provides a laser cutting method for a silicon ingot, which comprises the following steps: generating a subsurface scanning path and a target depth based on coordinate data of an operation station, wherein the scanning path is adaptively planned according to subsurface curvature and crystal orientation, and the target depth is determined as a preferential area of crack initiation inside the silicon ingot; when the first light beam is used to scan the target depth along the scanning path, an image sequence of crack formation is captured in real time by a high-resolution detector integrated in an optical imaging system; crack width data is extracted from the image sequence, and after filtering and normalization processing, the continuous distribution of the crack width is obtained; according to the crack width level, a corresponding crack control strategy is executed; and for the crack reaching a preset crack width level, a phase modulation system of the second light beam is started. The application realizes accurate control of the crack and adaptive planning of the cutting path, and improves the efficiency and quality of the silicon ingot cutting.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a laser cutting method for silicon ingots. Background Technology

[0002] In the semiconductor industry, silicon ingots are the primary material for manufacturing silicon wafers, and their cutting technology directly impacts wafer quality and production efficiency. Silicon wafers are a key substrate for manufacturing products such as integrated circuits and solar cells. With the miniaturization of electronic devices and increasing performance requirements, the demands on silicon ingot cutting technology are also rising. Traditional silicon ingot cutting methods include mechanical cutting and laser cutting. Laser cutting technology offers advantages such as high precision, high efficiency, low damage, and ease of automation; however, there is still room for improvement in the precision and efficiency of laser cutting of silicon ingots.

[0003] Prior art 1, publication number CN120709260A, discloses a method for fabricating alignment marks in semiconductor packaging and its product, including the following steps: preparing a dam on optical glass at a position corresponding to the TSV region; coating the dam with bonding adhesive; bonding the wafer to the optical glass and grinding to thin it; etching to form a first-order trench and alignment mark; completing the through-silicon via etching; preparing a dielectric layer on the wafer; preparing a passivation layer on the dielectric layer; preparing an RDL redistribution layer; pre-cutting a groove, half-cutting to the dam; preparing a solder mask layer; planting solder balls or printing solder balls, and then cutting into the final product. While it can achieve the alignment function of photolithography process after pre-cutting, improve the overall process capability, reduce process steps, shorten product manufacturing cycle, reduce packaging cost, and enhance product competitiveness; it does not require a dedicated laser marking station, reduces wafer surface contamination caused by laser marking, saves the original laser marking station operators, saves manpower and material resources, saves a process, and reduces packaging cost; however, it does not directly involve the precision of laser cutting silicon ingots, which to some extent reduces the accuracy and efficiency of cutting.

[0004] Prior art two, publication number CN120280338A, discloses a wafer-level chip dicing method. This method includes: providing a wafer; coating a patterned surface of the wafer with photoresist; exposing the dicing paths for chip separation through exposure and development, while the photoresist protects other areas of the wafer; etching the dicing paths to a set depth, less than the final chip thickness, using dry or wet etching; covering the back of the wafer with an expandable film; and performing laser stealth dicing on the wafer to obtain multiple individual chips. Although this method minimizes edge chipping and cracking damage, resulting in a smooth side profile and a high yield, it does not consider real-time monitoring and control of cracks, thus failing to effectively reduce cracks and damage during the chip dicing process.

[0005] Prior art 3, publication number CN119092464A, discloses a semiconductor processing method, comprising: providing a wafer including a silicon layer, a dielectric layer, and a bonding layer; having a metal layer in at least a portion of the dicing path; fabricating a metal protective layer on the surface of the bonding layer; using dry etching to sequentially etch the metal protective layer, bonding layer, and dielectric layer along the dicing path until etching stops at the metal layer, forming a first etched trench segment; using laser etching to etch the bottom of the first etched trench segment until the metal layer is removed, forming a second etched trench segment; etching downwards along the dicing path direction according to the width of the first etched trench segment until stopping at a predetermined depth within the silicon layer; thinning the side of the silicon layer away from the dielectric layer until completely separated at the dicing path; removing the metal protective layer to form an independent chip. Although adding a metal protective layer to the bonding layer surface and placing the laser etching position below the bonding interface significantly improves the protection of the bonding layer interface, reduces warpage, and ensures the flatness and cleanliness of the bonding layer, it does not address the optimization of the cutting path and stress management. It cannot generate a local compressive stress field, and therefore cannot further optimize the cutting path and stress management.

[0006] Current technologies 1, 2, and 3 suffer from limitations in the precision and efficiency of laser cutting of silicon ingots. They also exhibit a relatively high probability of cracking and damage during the cutting process, leading to a need for further improvement in product yield. Therefore, this invention provides a laser cutting method for silicon ingots. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a laser cutting method for silicon ingots, comprising the following steps:

[0008] When the target depth is scanned along the scanning path using the first beam, the image sequence of crack formation is captured in real time by a high-resolution detector integrated in the optical imaging system; crack width data is extracted from the image sequence, and after filtering and normalization, a continuous distribution of crack width is obtained; the crack width is divided into multiple levels, and the level division is based on the statistical quantile of the width value, from level 1 to level N, where each level corresponds to the degree of potential risk of crack propagation.

[0009] Based on the crack width level, the corresponding crack control strategy is executed; for cracks that reach the preset crack width level, the phase modulation system of the second beam is activated to move along the scanning path with the first beam in synchronous tracking mode; the spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator to generate a local compressive stress field.

[0010] Optionally, the process of generating a continuous distribution of crack width includes the following steps:

[0011] The image sequence of crack formation is analyzed frame by frame. By identifying the gray-scale contrast edge between the crack and the matrix material in each frame, the crack outline is located. The center point of the crack outline is connected to generate a crack morphology skeleton that runs through the entire scanning area. Normal section analysis is performed along the crack morphology skeleton to calculate the width value of each section point, thereby outputting a set of original width datasets that correspond one-to-one with the scanning position.

[0012] The filtering intensity is dynamically adjusted based on the local fluctuations of the data points in the original width dataset to generate a smooth width curve. The smooth width curve is used for scale normalization to obtain the maximum width value in the entire scanning process, and the maximum width value is defined as the reference width. The absolute width value of each point in the smooth width curve is divided by the reference width to convert it into a relative width ratio between 0 and 1, resulting in a standardized crack width continuous distribution curve.

[0013] The statistical quantiles of the continuous crack width distribution curve are calculated, and the width range from 0 to 1 is divided into N continuous intervals, each interval corresponding to a crack width level; level 1 corresponds to the highest quantile interval, representing the maximum width; level N corresponds to the lowest quantile interval, representing the minimum width; the classification result directly defines the degree of crack propagation risk corresponding to each scanning position.

[0014] Optionally, the process of outputting a set of raw width datasets that correspond one-to-one with the scan positions includes the following steps:

[0015] A series of skeleton feature points are extracted from the skeleton lines of the generated crack morphology skeleton at equal intervals, and each feature point corresponds to a scanning position.

[0016] For each skeleton feature point, calculate its first derivative in the skeleton tangent direction at the skeleton feature point to determine the local skeleton orientation of the skeleton feature point; based on the local skeleton orientation, construct a normal analysis plane perpendicular to the skeleton.

[0017] The crack profile and the normal analysis plane are spatially intersected to obtain two intersection points, which represent the edge points on both sides of the crack. The Euclidean distance between the two intersection points is measured, which is the normal width value at the current skeleton feature point. The normal width values ​​at all skeleton feature points are arranged and combined according to their corresponding scanning positions to form the original width dataset that is completely synchronized with the scanning trajectory.

[0018] Optionally, the process of generating a local compressive stress field includes the following steps:

[0019] The preset stress control mapping table is queried according to the crack width level, and each width level is associated with a stress relief requirement; the stress relief requirement is defined as the local compressive stress intensity required to suppress the crack propagation of the level.

[0020] Based on the stress cancellation requirement, the phase modulation parameters that generate the corresponding light intensity distribution are solved in reverse. The phase modulation parameters are transmitted to the phase modulator in the optical path of the second beam. The phase modulator reconstructs the wavefront of the second beam according to the received phase modulation parameters. The original Gaussian wavefront of the second beam is adjusted to a non-Gaussian wavefront with a central light intensity depression. After the beam with the non-Gaussian wavefront is focused, it forms a ring-shaped spot at the target depth.

[0021] The second beam control system acquires motion coordinates along the subsurface scanning path in real time from the first beam control system; based on the motion coordinates and combined with the fixed position offset of the first beam, the second beam calculates its own synchronous tracking coordinates and drives the beam positioning system to move.

[0022] The annular light spot scans synchronously with the first beam at the target depth; the energy distribution characteristics of the annular light spot induce a local compressive stress field inside the silicon ingot that overlaps with the tensile stress zone generated by the first beam; the compressive stress field counteracts the tensile stress at the crack tip, effectively suppressing crack propagation.

[0023] Optionally, the energy distribution characteristics of the annular light spot induce a local compressive stress field within the silicon ingot that overlaps with the tensile stress region generated by the first beam, comprising the following steps:

[0024] By utilizing the central intensity depression characteristic of the annular spot, an annular energy deposition zone is formed at the target depth inside the silicon ingot during the scanning process; the geometry of the annular energy deposition zone is defined by the energy distribution of the annular spot, with the lowest energy in the central region and the highest energy in the annular region.

[0025] Based on the non-uniform energy distribution of the annular energy deposition zone, a radially inward stress gradient field is induced in the region surrounding the annular energy deposition zone through the absorption response of the material to laser energy. Due to the constraint effect of the annular energy deposition, the stress gradient field is transformed into a local compressive stress field with the center of the deposition zone as the focus.

[0026] Through synchronous scanning of the second beam and the first beam, the annular energy deposition zone always coincides with the tensile stress zone generated by the Gaussian spot of the first beam in space; this allows the local compressive stress field and the tensile stress zone to superimpose in the same spatial domain, offsetting the tensile stress at the crack tip and effectively suppressing crack propagation.

[0027] Optionally, the process of transforming the stress gradient field into a local compressive stress field with the center of the sedimentary zone as the focal point includes the following steps:

[0028] The non-uniform energy distribution in the annular energy deposition zone induces non-uniform thermoelastic expansion inside the silicon ingot; the high-energy region of the annular energy deposition zone undergoes thermal expansion, while the central low-energy region maintains a relatively stable lattice structure; the expansion difference forms a thermoelastic expansion field from the annular region to the central region inside the annular energy deposition zone.

[0029] The thermoelastic expansion field is constrained by the geometry of the annular energy deposition zone. The expansion of the geometric annular high-energy region is mechanically restricted by the adjacent low-temperature central region. The mechanical restriction transforms the radial thermoelastic expansion into pressure along the annular tangent. The pressure is superimposed inside the annular energy deposition zone, forming a radial pressure field pointing towards the center of the geometric shape of the annular energy deposition zone.

[0030] The radial pressure field reaches stress equilibrium in the central region of the annular energy deposition zone, which transforms into a high-pressure stress concentration zone with the center of the annular energy deposition zone as the focus. The high-pressure stress concentration zone is defined as a local compressive stress field.

[0031] Optionally, the process of forming a radial pressure field pointing towards the center of the geometry of the annular energy deposition zone includes the following steps:

[0032] Based on the radial expansion trend of the annular region generated by the thermoelastic expansion field, the radial expansion trend displacement of the annular region is rigidly constrained in the radial direction by the stable lattice structure of the central low-energy region; the rigid constraint forms the strain coordination condition in three-dimensional space, storing the radial expansion strain energy that cannot be released as elastic potential energy.

[0033] The stored elastic potential energy undergoes an energy state transformation through the material constitutive relation and is redistributed to the tangential dimension where the strain is relatively free according to the principle of minimum potential energy. The energy redistribution process causes the material in the annular region to generate compressive strain along the circumferential direction. The compressive strain is transformed into circumferential compressive stress through the stress-strain relationship. The circumferential compressive stress forms a continuously distributed tangential pressure element in the annular section, and its intensity is proportional to the stored elastic potential energy.

[0034] Each tangential pressure element generates a normal component force pointing towards the center of curvature in the annular structure; through stress field superposition calculation, the discrete normal components are integrated into a continuous pressure field within the annular energy deposition zone; the pressure field exhibits a gradient distribution that increases radially from the annular region to the central region, and finally forms a pressure extremum at the geometric center of the deposition zone, establishing a complete radial pressure field.

[0035] Optionally, the process of integrating discrete normal components into a continuous pressure field within the annular energy deposition zone includes the following steps:

[0036] A polar coordinate system is established with the geometric center of the annular energy deposition zone as the origin, and each discrete normal force component is mapped to the angular position in the polar coordinate system. Based on the coordinates of the point of application and the force vector of the discrete normal force component, the projection component of each component in the radial direction is obtained, forming a set of discrete radial force data points.

[0037] For discrete radial force data points, linear interpolation based on angular position is used to generate a continuous force density distribution function between adjacent data points, defining the radial force density value at any angular position within the annular energy deposition zone. An annular surface integral is then performed on the continuous force density distribution function, with the integration process proceeding along the entire circumference of the annular energy deposition zone. The force density value at each angular position is multiplied by the corresponding infinitesimal arc length, and the contributions of all infinitesimal elements are accumulated. Finally, a radial pressure distribution function is output, describing the continuous change of pressure along the radial direction.

[0038] The radial pressure distribution function defines a continuous pressure field within the annular energy deposition zone. The pressure field exhibits a gradient characteristic that increases radially from the annular region to the central region, and reaches the pressure extremum at the geometric center of the deposition zone, thus completing the synthesis from discrete normal components to a continuous pressure field.

[0039] Optionally, the process of generating a continuous force density distribution function between adjacent data points includes the following steps:

[0040] The discrete radial force data points are sorted according to their angular positions to form an ordered data sequence; for any two adjacent data points in the data sequence, the angular difference and the radial force difference are calculated.

[0041] Based on the angle difference and radial force difference between two adjacent data points, a linear relationship between the angular position and the radial force value is established; for any angular position between two adjacent data points, the radial force value at any angular position is calculated by linear interpolation, that is, the radial force value is distributed proportionally according to the relative position of the angle between the two points.

[0042] The entire circumference of the annular energy deposition zone is divided into continuous micro-angle intervals. Linear interpolation is applied to each micro-angle interval to calculate the radial force values ​​at all angular positions within the entire circumference, forming a continuous force density distribution function. The force density distribution function defines the radial force density value at any angular position within the annular energy deposition zone.

[0043] Optionally, it also includes capturing the surface reflection characteristics from the laser source of the silicon ingot toward the surface through an optical imaging system to identify the position of the operating station, which is defined as a local high-reflectivity area in the surface region aligned with the optical path of the laser source; based on the coordinate data of the operating station, a subsurface scanning path and a target depth are generated, wherein the scanning path is adaptively planned according to the subsurface curvature and crystal orientation, and the target depth is determined by optical penetration calculation as the priority area for crack initiation inside the silicon ingot; the first beam is configured as a Gaussian spot, and its focal point is calibrated to the target depth.

[0044] This invention achieves efficient crack control and precise cutting path planning through a series of steps. It captures the reflection characteristics of the silicon ingot surface using an optical imaging system, accurately identifying localized high-reflection areas aligned with the laser source's optical path, providing precise positioning for laser cutting. Based on the silicon ingot surface curvature and crystal orientation, a subsurface scanning path is adaptively planned, taking into account the physical characteristics of the silicon ingot for more precise cutting. Optical penetration calculations determine the priority region for crack initiation, i.e., the target depth, ensuring that laser cutting reaches the crack initiation region inside the silicon ingot. A high-resolution detector captures real-time image sequences of crack formation and extracts crack width data, enabling continuous monitoring of crack development. By filtering and normalizing the crack width data, a continuous distribution of crack width is obtained, further dividing the crack width into multiple levels to provide a basis for crack control. Corresponding crack control strategies are executed according to the crack width level. For cracks reaching the preset crack width level, the phase modulation system of the second beam is activated, moving synchronously with the first beam along the scanning path in a synchronized tracking mode, achieving effective crack control. The spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator, generating a local compressive stress field, which helps control crack propagation and improves cutting quality and efficiency.

[0045] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0046] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0047] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 This is a flowchart of the laser cutting method for silicon ingots in Embodiment 1 of the present invention;

[0049] Figure 2 This is a schematic diagram of the laser cutting method for silicon ingots in Embodiment 2 of the present invention;

[0050] Figure 3 This is a process diagram of generating a subsurface scanning path and target depth in Embodiment 3 of the present invention;

[0051] Figure 4 This is a process diagram illustrating the continuous distribution of crack width in Embodiment 5 of the present invention;

[0052] Figure 5 This is a process diagram of generating a local compressive stress field in Embodiment 8 of the present invention. Detailed Implementation

[0053] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0054] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0055] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] Example 1: As Figure 1 As shown, this embodiment of the invention provides a laser cutting method for silicon ingots, comprising the following steps:

[0057] S100: The laser source from the silicon ingot is directed towards the surface, and the surface reflection characteristics are captured by the optical imaging system to identify the position of the operating station. The position is defined as a local high-reflection area in the surface region aligned with the laser source optical path. Based on the coordinate data of the operating station, a subsurface scanning path and a target depth are generated. The scanning path is adaptively planned according to the subsurface curvature and crystal orientation, and the target depth is determined by optical penetration calculation as the priority area for crack initiation inside the silicon ingot. The first beam is configured as a Gaussian spot, and its focal point is calibrated to the target depth.

[0058] S200: When the first beam scans the target depth along the scanning path, a high-resolution detector integrated in the optical imaging system captures the image sequence of crack formation in real time; crack width data is extracted from the image sequence, and after filtering and normalization, a continuous distribution of crack width is obtained; the crack width is divided into multiple levels, and the level division is based on the statistical quantile of the width value, from level 1 (maximum width) to level N (minimum width), where each level corresponds to the potential risk level of crack propagation;

[0059] S300: Based on the crack width level, execute the corresponding crack control strategy; for cracks that reach the preset crack width level, activate the phase modulation system of the second beam to move along the scanning path with the first beam in synchronous tracking mode; the spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator to generate a local compressive stress field.

[0060] The working principle and beneficial effects of the above technical solution are as follows: In this embodiment, the laser source of the silicon ingot is directed towards the surface, and the surface reflection characteristics are captured by an optical imaging system to identify the position of the operating station. The position is defined as a local high-reflection area in the surface region aligned with the optical path of the laser source. Based on the coordinate data of the operating station, a subsurface scanning path and a target depth are generated. The scanning path is adaptively planned according to the subsurface curvature and crystal orientation, and the target depth is determined by optical penetration calculation as the priority area for crack initiation inside the silicon ingot. The first beam is configured as a Gaussian spot, and its focal point is calibrated to the target depth. Secondly, when the first beam scans the target depth along the scanning path, the high-reflection area integrated in the optical imaging system is used to detect the reflection characteristics of the surface. A resolution detector captures image sequences of crack formation in real time; crack width data is extracted from the image sequences, filtered, and normalized to obtain a continuous distribution of crack width; the crack width is divided into multiple levels based on the statistical quantiles of the width values, from level 1 (maximum width) to level N (minimum width), where each level corresponds to the potential risk of crack propagation; finally, a corresponding crack control strategy is executed according to the crack width level; for cracks reaching the preset crack width level, the phase modulation system of the second beam is activated, moving along the scanning path with the first beam in a synchronous tracking mode; the spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator, generating a local compressive stress field (the specific principle is as follows). Figure 2 (As shown). The above scheme achieves efficient crack control and precise cutting path planning through a series of steps. It captures the reflection characteristics of the silicon ingot surface using an optical imaging system, accurately identifying local high-reflection areas aligned with the laser source's optical path, providing precise positioning for laser cutting. Based on the silicon ingot surface curvature and crystal orientation, a subsurface scanning path is adaptively planned, taking into account the physical characteristics of the silicon ingot to achieve more precise cutting. Optical penetration calculations determine the priority region for crack initiation, i.e., the target depth, ensuring that laser cutting can directly reach the crack initiation region inside the silicon ingot. A high-resolution detector captures the image sequence of crack formation in real time, extracting crack width data to achieve continuous monitoring of crack development. By filtering and normalizing the crack width data, a continuous distribution of crack width is obtained, further dividing the crack width into multiple levels, providing a basis for crack control. Corresponding crack control strategies are executed according to the crack width level. For cracks reaching the preset crack width level, the phase modulation system of the second beam is activated, moving along the scanning path in a synchronous tracking mode with the first beam, achieving effective crack control. The spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator, generating a local compressive stress field, which helps control crack propagation and improves cutting quality and efficiency.

[0061] In summary, this embodiment enables precise control of cracks and adaptive planning of the cutting path during the cutting process, thereby improving the efficiency and quality of silicon ingot cutting.

[0062] Example 2: Figure 3 As shown, based on Example 1, the process of generating a subsurface scanning path and target depth provided by this embodiment of the invention specifically includes the following steps:

[0063] S101: Based on the coordinates of the local high-reflectivity area captured by the optical imaging system, the distribution of surface curvature and crystal orientation are extracted; the distribution of surface curvature is obtained by analyzing the spot distortion mode of the local high-reflectivity area; the crystal orientation is derived by analyzing the polarization anisotropy characteristics of the reflected light.

[0064] S102: Geometric correction of the subsurface scanning path is performed using the distribution of surface curvature. The subsurface scanning path dynamically adjusts its trajectory according to the curvature change. At the same time, the direction of the subsurface scanning path is aligned with the easily fractured crystal plane of the crystal by combining crystal orientation, thereby generating a continuous and smooth subsurface scanning path.

[0065] S103: Optical penetration calculation calibrates the energy attenuation of the laser in silicon material based on the local high reflectivity characteristics of the operating station, simulating the energy deposition distribution of the beam inside the silicon ingot; according to the peak region of the energy deposition distribution, the priority region for crack initiation is identified, and the target depth is set as the center depth of the priority region; the subsurface scanning path and target depth are integrated into the control system of the first beam for scanning operation.

[0066] The working principle and beneficial effects of the above technical solution are as follows: First, based on the coordinates of the local high-reflectivity area captured by the optical imaging system, the distribution of surface curvature and crystal orientation are extracted; the distribution of surface curvature is obtained by analyzing the spot distortion mode of the local high-reflectivity area; the crystal orientation is derived by analyzing the polarization anisotropy characteristics of the reflected light; secondly, the geometric correction of the subsurface scanning path is performed using the distribution of surface curvature, and the trajectory of the subsurface scanning path is dynamically adjusted according to the curvature change; at the same time, combined with the crystal orientation, the direction of the subsurface scanning path is aligned with the easily fractured crystal plane of the crystal to generate a continuous and smooth subsurface scanning path; finally, the optical penetration calculation is based on the local high-reflectivity characteristics of the operating position to calibrate the energy attenuation of the laser in the silicon material, simulating the energy deposition distribution of the beam inside the silicon ingot; according to the peak region of the energy deposition distribution, the priority region for crack initiation is identified, and the target depth is set as the center depth of the priority region; the subsurface scanning path and the target depth are integrated into the control system of the first beam for scanning operation. The above-described scheme, by extracting the surface curvature distribution and crystal orientation of local high-reflectivity areas, enables more accurate geometric correction of the subsurface scanning path, thereby improving the accuracy and reliability of the scanning path. Combining surface curvature distribution and crystal orientation to dynamically adjust the subsurface scanning path trajectory, making it continuous and smooth, helps improve scanning efficiency and quality. By simulating the energy deposition distribution of laser in silicon and identifying the preferential region for crack initiation, the target depth can be set more accurately, improving the accuracy of crack initiation point identification. Integrating the subsurface scanning path and target depth into the beam control system enables more stable and precise scanning operations. By comprehensively considering factors such as surface curvature, crystal orientation, and laser energy deposition distribution, the scanning path and depth can be controlled more effectively, thereby improving the processing quality and efficiency of silicon materials.

[0067] Example 3: Based on Example 2, the process of generating a continuous and smooth subsurface scanning path provided by this embodiment of the invention specifically includes the following steps:

[0068] S1021: The focus compensation vector required for each path point position is obtained based on the distribution of surface curvature. The focus compensation vector is dynamically generated according to the sign and amplitude of the surface curvature. When the surface curvature is positive, the compensation vector points into the silicon ingot to compensate for the premature convergence of the beam. When the surface curvature is negative, the compensation vector points out of the silicon ingot to compensate for the delayed convergence of the beam. All path points that have undergone focus compensation are connected in sequence to form a geometric correction path.

[0069] S1022: The spatial orientation of the easily fractured crystal plane is resolved from the crystal orientation data, and a scanning direction vector is obtained; the overall direction of the geometric correction path is projected and aligned with the scanning direction vector to generate a path direction adjustment matrix; the path direction adjustment matrix is ​​applied to perform spatial transformation on the geometric correction path so that the tangent direction of the entire geometric correction path remains parallel to the easily fractured crystal plane, generating a continuous and smooth subsurface scanning path.

[0070] S1023: A continuous smooth subsurface scanning path is transmitted to the control system of the first beam as a trajectory command for its scanning motion.

[0071] The working principle and beneficial effects of the above technical solution are as follows: Firstly, this embodiment derives the required focus compensation vector for each path point based on the distribution of surface curvature. The focus compensation vector is dynamically generated based on the sign and amplitude of the surface curvature. When the surface curvature is positive, the compensation vector points inward to counteract premature beam convergence; when the surface curvature is negative, the compensation vector points outward to compensate for delayed beam convergence. All path points that have undergone focus compensation are sequentially connected to form a geometric correction path. Secondly, the spatial orientation of the easily fractured crystal plane is analyzed from the crystal orientation data, and a scanning direction vector is obtained. The overall orientation of the geometric correction path is projected and aligned with the scanning direction vector to generate a path direction adjustment matrix. The path direction adjustment matrix is ​​applied to spatially transform the geometric correction path, ensuring that the tangent direction of the entire geometric correction path remains parallel to the easily fractured crystal plane, generating a continuous and smooth subsurface scanning path. Finally, the continuous and smooth subsurface scanning path is transmitted to the control system of the first beam as the trajectory command for its scanning motion. This solution, through the dynamic generation of the focus compensation vector, can precisely adjust the focus of the beam, eliminate the influence of surface curvature changes on beam convergence, and improve the accuracy of the scanning path. Connecting the path points after focus compensation sequentially forms a continuous and smooth geometric correction path. By keeping the tangent direction of the geometric correction path parallel to the easily fractured crystal plane, stress concentration in the crystal during scanning can be reduced, crack formation can be avoided, and cutting quality can be improved. Transmitting the continuous and smooth subsurface scanning path to the beam control system allows for automatic control of the beam's scanning motion according to preset trajectory commands, improving processing efficiency and automation.

[0072] In summary, this embodiment can achieve precise adjustment and optimization of the subsurface scanning path, improve scanning accuracy and cutting quality, reduce processing risks, and enhance the automation and intelligence level of the entire system.

[0073] Example 4: Based on Example 2, the process for identifying the preferred region for crack initiation provided in this embodiment of the invention specifically includes the following steps:

[0074] S1031: Utilize the characteristics of the local high-reflectivity area of ​​the operating station, which are obtained by capturing the coordinates of the local high-reflectivity area through an optical imaging system; quantify the local high-reflectivity characteristics into a surface reflectivity parameter, representing the proportion of laser energy reflected on the surface of the operating station; convert the surface reflectivity parameter into a surface energy coupling coefficient through derivation, defining the initial proportion of laser energy actually entering the silicon ingot.

[0075] S1032: The initial boundary conditions for energy attenuation are adjusted by the surface energy coupling coefficient, and the energy input at the surface is matched with the surface energy coupling coefficient; a calibrated exponential attenuation behavior of laser energy with penetration depth is output; the exponential attenuation behavior is convolved with the Gaussian spot spatial distribution of the first beam to simulate the energy deposition of the beam in the three-dimensional space inside the silicon ingot, and the three-dimensional energy deposition distribution is output, where each point represents the deposited energy value at the location inside the silicon ingot;

[0076] S1033: Perform spatial gradient analysis on the three-dimensional energy deposition distribution to extract all local energy deposition peak points; connect the local energy deposition peak points to form a continuous high-energy deposition domain, which is defined as the priority region for crack initiation; the target depth is set as the geometric center depth of the priority region.

[0077] The working principle and beneficial effects of the above technical solution are as follows: This embodiment first utilizes the characteristics of the local high-reflectivity area of ​​the operating station, which is obtained by capturing the coordinates of the local high-reflectivity area through an optical imaging system; the local high-reflectivity characteristics are quantified into a surface reflectivity parameter, representing the proportion of laser energy reflected on the surface of the operating station; the surface reflectivity parameter is converted into a surface energy coupling coefficient through derivation, defining the initial proportion of laser energy actually entering the silicon ingot; secondly, the initial boundary conditions of energy attenuation are adjusted through the surface energy coupling coefficient, matching the energy input at the surface with the surface energy coupling coefficient; a calibrated exponential decay behavior of laser energy with penetration depth is output; the exponential decay behavior is convolved with the Gaussian spot spatial distribution of the first beam to simulate the energy deposition of the beam in the three-dimensional space inside the silicon ingot, outputting a three-dimensional energy deposition distribution, where each point represents the deposited energy value at a location inside the silicon ingot; finally, spatial gradient analysis is performed on the three-dimensional energy deposition distribution to extract all local energy deposition peak points; the local energy deposition peak points are connected to form a continuous high-energy deposition domain, which is defined as the priority region for crack initiation; the target depth is set as the geometric center depth of the priority region. The aforementioned scheme captures and quantifies local high reflectivity characteristics using an optical imaging system, converting them into surface energy coupling coefficients to accurately identify regions in the silicon ingot that may be prone to cracking due to laser energy. The initial boundary conditions for energy attenuation are adjusted to simulate the attenuation behavior of laser energy within the silicon ingot, and convolution calculations are performed with the spatial distribution of the Gaussian spot to obtain the three-dimensional energy deposition distribution within the silicon ingot. Spatial gradient analysis of the three-dimensional energy deposition distribution is used to extract local energy deposition peaks, which are then connected to form high-energy deposition domains, identifying the preferred regions where crack initiation is most likely. The target depth is set to the geometric center depth of the preferred region to ensure more effective control over crack initiation and propagation during processing.

[0078] In summary, this embodiment improves the accuracy and reliability of crack control during silicon ingot processing through precise measurement and simulation, reduces the risk of crack formation, and thus improves the processing quality and efficiency of silicon ingots.

[0079] Example 5: Figure 4 As shown, based on Example 1, the process for generating a continuous distribution of crack width provided by this embodiment of the invention specifically includes the following steps:

[0080] S201: Perform frame-by-frame analysis on the image sequence of crack formation. By identifying the gray-scale contrast edge between the crack and the matrix material in each frame, locate the crack outline. Connect the center points of the crack outline to generate a crack morphology skeleton that runs through the entire scanning area. Perform normal section analysis along the crack morphology skeleton to calculate the width value of each section point, thereby outputting a set of original width datasets that correspond one-to-one with the scanning position.

[0081] S202: Dynamically adjust the filtering intensity of the original width dataset according to the local fluctuations of the data points to generate a smooth width curve; use the smooth width curve to perform scale normalization to obtain the maximum width value in the entire scanning process, and define the maximum width value as the reference width; divide the absolute width value of each point in the smooth width curve by the reference width to convert it into a relative width ratio between 0 and 1, and obtain a standardized crack width continuous distribution curve.

[0082] S203: Calculate the statistical quantiles of the continuous distribution curve of crack width, divide the width range from 0 to 1 into N continuous intervals, each interval corresponding to a crack width level; level 1 corresponds to the highest quantile interval, representing the maximum width; level N corresponds to the lowest quantile interval, representing the minimum width; the classification result directly defines the degree of crack propagation risk corresponding to each scanning position.

[0083] The working principle and beneficial effects of the above technical solution are as follows: First, the image sequence of crack formation is analyzed frame by frame. By identifying the gray-scale contrast edge between the crack and the substrate material in each frame, the crack outline is located. The center points of the crack outline are connected to generate a crack morphology skeleton that runs through the entire scanning area. Normal section analysis is performed along the crack morphology skeleton to calculate the width value of each section point, thereby outputting a set of original width datasets corresponding one-to-one with the scanning position. Second, the filtering intensity of the original width dataset is dynamically adjusted according to the local fluctuations of the data points to generate a smooth width curve. The smooth width curve is then used for scale normalization. The method involves obtaining the maximum crack width during the entire scanning process and defining this maximum width as the baseline width. The absolute width value at each point on the smooth width curve is divided by the baseline width to convert it into a relative width ratio between 0 and 1, resulting in a standardized continuous crack width distribution curve. Finally, the statistical quantiles of the continuous crack width distribution curve are calculated, dividing the width range from 0 to 1 into N continuous intervals, each interval corresponding to a crack width level. Level 1 corresponds to the highest quantile interval, representing the maximum width; Level N corresponds to the lowest quantile interval, representing the minimum width. The grading result directly defines the crack propagation risk level corresponding to each scanning position. This method achieves accurate measurement and quantitative analysis of the continuous distribution of crack width data. The crack outline is accurately located by analyzing the image sequence frame by frame, generating a crack morphology skeleton, and the width value is calculated by analyzing the normal section along this skeleton. Subsequently, the original data is filtered to reduce local fluctuations, generating a smooth width curve. Scale normalization converts the width values ​​into relative values, standardizing the width data for easier comparison and analysis. Finally, by calculating the statistical quantiles of the standardized curve, the crack width range was divided into multiple continuous intervals, corresponding to different crack width levels, thereby quantitatively classifying the crack propagation risk. This ultimately achieved accurate measurement and risk assessment of the continuous crack width distribution from image acquisition, providing a scientific basis for crack detection and analysis.

[0084] Example 6: Based on Example 5, the process of outputting a set of original width datasets corresponding one-to-one with the scan positions provided in this embodiment of the invention specifically includes the following steps:

[0085] S2011: Extract a series of skeleton feature points at equal intervals from the skeleton lines of the generated crack morphology skeleton, with each feature point corresponding to a scanning position;

[0086] S2012: For each skeleton feature point, calculate its first derivative in the skeleton tangent direction of the skeleton feature point to determine the local skeleton orientation of the skeleton feature point; based on the local skeleton orientation, construct a normal analysis plane perpendicular to the skeleton.

[0087] Specifically, for each skeleton feature point, based on the coordinate sequence of that point in the crack morphology skeleton, the first derivative estimate of the skeleton tangent direction at that point is obtained by calculating the coordinate difference vector between its adjacent points; this first derivative estimate defines the instantaneous change direction of the skeleton at that point and determines the local skeleton orientation.

[0088] S2013: Perform spatial intersection calculation between the crack profile and the normal analysis plane to obtain two intersection points, which represent the edge points on both sides of the crack respectively; measure the Euclidean distance between the two intersection points, which is the normal width value at the current skeleton feature point; arrange and combine the normal width values ​​at all skeleton feature points according to their corresponding scanning positions to form the original width dataset that is completely synchronized with the scanning trajectory.

[0089] The working principle and beneficial effects of the above technical solution are as follows: First, this embodiment extracts a series of skeleton feature points at equal intervals from the skeleton lines of the generated crack morphology skeleton, with each feature point corresponding to a scanning position. Second, for each skeleton feature point, the first derivative of its skeleton tangent direction at the feature point is calculated to determine the local skeleton orientation. Based on the local skeleton orientation, a normal analysis plane perpendicular to the skeleton is constructed. Finally, the crack profile and the normal analysis plane are spatially intersected to obtain two intersection points, representing the edge points on both sides of the crack. The Euclidean distance between the two intersection points is measured, which is the normal width value at the current skeleton feature point. The normal width values ​​at all skeleton feature points are arranged and combined according to their corresponding scanning positions to form an original width dataset completely synchronized with the scanning trajectory. This solution, by extracting skeleton feature points at equal intervals, ensures precise capture of the crack morphology, with each feature point's location corresponding one-to-one with the actual scanning position, thus improving the spatial resolution of crack analysis. Using the first derivative of the skeleton feature points to determine the local skeleton orientation accurately reflects the local crack propagation direction. A normal analysis plane perpendicular to the local skeleton is constructed based on the local skeleton orientation to ensure the accuracy of crack width measurement, as it simulates the actual local development of the crack. Edge points on both sides of the crack are obtained through spatial intersection calculations, accurately determining the crack boundary and providing precise reference points for crack width measurement. Measuring the Euclidean distance between two edge points yields the normal width value, providing a precise numerical value for the crack width and avoiding human error. All normal width values ​​are arranged and combined with their corresponding scan positions to form a raw width dataset that is completely synchronized with the scan trajectory, ensuring data consistency and reliability.

[0090] In summary, this embodiment makes the crack detection process more automated and precise, improves the efficiency and accuracy of crack analysis, and provides strong technical support for crack assessment and monitoring.

[0091] Example 7: Based on Example 6, the process of spatially intersecting the crack profile with the normal analysis plane provided in this embodiment of the invention specifically includes the following steps:

[0092] S20131: Substitute each profile point in the crack profile into the plane equation of the normal analysis plane for verification; all profile points that satisfy the plane equation and are located on the normal analysis plane are identified, forming a candidate intersection set;

[0093] S20132: Spatial partitioning of the candidate intersection point set, drawing a direction vector from the current skeleton feature point to each point in the candidate intersection point set, and dividing the candidate points into two subsets by calculating the dot product sign of the direction vector and the normal vector of the analysis plane: the first side candidate point set located on one side of the skeleton and the second side candidate point set located on the other side of the skeleton;

[0094] S20133: Find the point closest to the current skeleton feature point in the first candidate point set and the second candidate point set respectively; these are defined as the first edge point and the second edge point of the crack on the normal section respectively; the first edge point and the second edge point obtained are the two intersection points obtained by spatial intersection calculation, which are used to calculate the normal width value.

[0095] The working principle and beneficial effects of the above technical solution are as follows: In this embodiment, each contour point in the crack profile is first substituted into the plane equation of the normal analysis plane for verification; all contour points that satisfy the plane equation, i.e., those located on the normal analysis plane, are identified and form a candidate intersection point set; secondly, the candidate intersection point set is spatially partitioned, and a direction vector is drawn from the current skeleton feature point to each point in the candidate intersection point set. By calculating the dot product sign of the direction vector and the normal vector of the normal analysis plane, the candidate points are divided into two subsets: a first-side candidate point set located on one side of the skeleton and a second-side candidate point set located on the other side of the skeleton; finally, the point closest to the current skeleton feature point is found in the first-side candidate point set and the second-side candidate point set respectively; these are defined as the first edge point and the second edge point of the crack on the normal section respectively; the obtained first edge point and second edge point are the two intersection points obtained by spatial intersection calculation, which are used to calculate the normal width value. The aforementioned scheme achieves precise intersection of the crack profile and the normal analysis plane, accurately identifying the crack boundary in a specific direction. It allows for detailed analysis of the crack's spatial distribution and propagation trend, which is crucial for crack detection, assessment, and management. Specifically, by matching the crack profile points with the equation of the normal analysis plane, the intersection points of the crack and the plane can be accurately identified, improving the accuracy of crack analysis. Spatial partitioning of the candidate intersection point set clarifies the distribution of the crack on both sides of the normal analysis plane, aiding in a deeper understanding of the crack's spatial morphology. By identifying the point closest to the skeleton feature point as the crack edge point, the crack boundary location can be determined more accurately, providing important reference points for crack analysis and treatment. The determined first and second edge points allow for the calculation of the crack width on the normal analysis plane, crucial for quantitative crack analysis and assessment. Furthermore, the identification and analysis of crack edge points can predict crack propagation trends, providing guidance for structural safety assessment and maintenance.

[0096] In summary, this embodiment not only improves the accuracy of crack analysis, but also provides strong technical support for crack spatial morphology analysis, boundary identification, width calculation, and crack propagation trend prediction.

[0097] Example 8: As Figure 5 As shown, based on Example 1, the process for generating a local compressive stress field provided by this embodiment of the invention specifically includes the following steps:

[0098] S301: Based on the crack width level, query the preset stress control mapping table and associate each width level with a stress relief requirement; the stress relief requirement is defined as the local compressive stress intensity required to suppress the propagation of the level crack.

[0099] S302: Based on the stress cancellation requirement, the phase modulation parameters that generate the corresponding light intensity distribution are solved in reverse. The phase modulation parameters are transmitted to the phase modulator on the optical path of the second beam. The phase modulator reconstructs the wavefront of the second beam according to the received phase modulation parameters. The original Gaussian wavefront of the second beam is adjusted to a non-Gaussian wavefront with a central light intensity depression. After the beam with the non-Gaussian wavefront is focused, it forms a ring-shaped spot at the target depth.

[0100] S303: The second beam control system obtains the motion coordinates along the subsurface scanning path in real time from the first beam control system; the second beam calculates its own synchronous tracking coordinates based on the motion coordinates and the fixed position offset from the first beam, and drives the beam positioning system to move.

[0101] S304: The annular light spot scans synchronously with the first beam at the target depth; the energy distribution characteristics of the annular light spot induce a local compressive stress field inside the silicon ingot that overlaps with the tensile stress zone generated by the first beam; the compressive stress field counteracts the tensile stress at the crack tip, effectively suppressing crack propagation.

[0102] The working principle and beneficial effects of the above technical solution are as follows: First, this embodiment queries a preset stress control mapping table based on the crack width level, associating each width level with a stress relief requirement; the stress relief requirement is defined as the local compressive stress intensity required to suppress the propagation of the level crack; second, based on the stress relief requirement, the phase modulation parameters that generate the corresponding light intensity distribution are solved in reverse, and the phase modulation parameters are transmitted to the phase modulator on the second beam's optical path; the phase modulator reconstructs the wavefront of the second beam according to the received phase modulation parameters; the original Gaussian wavefront of the second beam is adjusted to a non-Gaussian wavefront with a central light intensity depression feature; possessing non-Gaussian... After being focused, the beam in front of the spool forms a ring-shaped spot at the target depth. Then, the second beam control system acquires the motion coordinates along the subsurface scanning path in real time from the first beam control system. Based on these motion coordinates and combined with the fixed position offset from the first beam, the second beam calculates its own synchronous tracking coordinates and drives the beam positioning system to move. Finally, the ring-shaped spot scans synchronously with the first beam at the target depth. The energy distribution characteristics of the ring-shaped spot induce a local compressive stress field within the silicon ingot that overlaps with the tensile stress zone generated by the first beam. This compressive stress field counteracts the tensile stress at the crack tip, effectively suppressing crack propagation. This scheme effectively suppresses crack propagation in materials. First, by consulting a stress control mapping table, the crack width level is correlated with the stress counteraction requirement, providing precise parameter basis for subsequent stress control. Next, the phase modulation parameters that generate the corresponding light intensity distribution are solved in reverse. The wavefront of the second beam is then adjusted using a phase modulator to create a non-Gaussian wavefront with a central intensity depression, thereby forming a ring-shaped spot at the target depth. This ring-shaped spot scans synchronously with the first beam, inducing a local compressive stress field within the silicon ingot. This compressive stress field overlaps with the tensile stress region generated by the first beam, effectively counteracting the tensile stress at the crack tip and effectively suppressing crack propagation. This not only improves the material's stability and service life but also reduces the risk of material failure due to crack propagation.

[0103] Example 9: Based on Example 8, the energy distribution characteristics of the annular light spot provided in this embodiment of the invention induce a local compressive stress field inside the silicon ingot that overlaps with the tensile stress region generated by the first light beam. Specifically, this includes the following steps:

[0104] S3041: Utilizing the central intensity depression characteristic of the annular spot, an annular energy deposition zone is formed at the target depth inside the silicon ingot during the scanning process; the geometry of the annular energy deposition zone is defined by the energy distribution of the annular spot, with the lowest energy in the central region and the highest energy in the annular region.

[0105] S3042: Based on the non-uniform energy distribution of the annular energy deposition zone, a radially inward stress gradient field is induced in the region surrounding the annular energy deposition zone through the material's absorption response to laser energy; due to the constraint effect of the annular energy deposition, the stress gradient field is transformed into a local compressive stress field with the center of the deposition zone as the focus.

[0106] S3043: Through the synchronous scanning of the second beam and the first beam, the annular energy deposition zone always coincides with the tensile stress zone generated by the Gaussian spot of the first beam in space; this allows the local compressive stress field and the tensile stress zone to be superimposed in the same spatial domain, thus offsetting the tensile stress at the crack tip and effectively suppressing crack propagation.

[0107] The working principle and beneficial effects of the above technical solution are as follows: First, this embodiment utilizes the central intensity depression characteristic of the annular spot to form an annular energy deposition zone at the target depth inside the silicon ingot during the scanning process; the geometry of the annular energy deposition zone is defined by the energy distribution of the annular spot, with the lowest energy in the central region and the highest energy in the annular region; second, based on the non-uniform energy distribution of the annular energy deposition zone, a radially inward stress gradient field is induced in the region surrounding the annular energy deposition zone through the absorption response of the material to the laser energy; due to the constraint effect of the annular energy deposition, the stress gradient field is transformed into a local compressive stress field with the center of the deposition zone as the focus; finally, through the synchronous scanning of the second beam and the first beam, the annular energy deposition zone always coincides with the tensile stress zone generated by the Gaussian spot of the first beam in space; this allows the local compressive stress field and the tensile stress zone to superimpose in the same spatial domain, offsetting the tensile stress at the crack tip and effectively suppressing crack propagation. The above-described scheme, combining the energy distribution characteristics of the annular light spot with synchronous scanning technology, achieves the technical effect of precisely controlling the stress field distribution inside the silicon ingot. By forming an annular energy deposition zone at the target depth inside the silicon ingot, a non-uniform stress gradient field is generated, which is then transformed into a local compressive stress field. The local compressive stress field and the tensile stress zone generated by the Gaussian light spot spatially overlap, and their superposition can offset the tensile stress at the crack tip, effectively suppressing crack propagation. This is beneficial for improving the processing quality and reliability of silicon ingots, preventing cracks from forming during processing, and ensuring the integrity and performance of the silicon ingot.

[0108] Example 10: Based on Example 9, the process of transforming the stress gradient field provided in this embodiment of the invention into a local compressive stress field with the center of the sedimentary zone as the focus specifically includes the following steps:

[0109] S30421: The non-uniform energy distribution of the annular energy deposition zone induces non-uniform thermoelastic expansion inside the silicon ingot; the high-energy region of the annular energy deposition zone undergoes thermal expansion, while the central low-energy region maintains a relatively stable lattice structure; the expansion difference forms a thermoelastic expansion field inside the annular energy deposition zone that points from the annular region to the central region.

[0110] S30422: The thermoelastic expansion field is constrained by the geometry of the annular energy deposition zone. The expansion of the geometric annular high-energy region is mechanically restricted by the adjacent low-temperature central region. The mechanical restriction transforms the radial thermoelastic expansion into pressure along the annular tangent. The pressure is superimposed inside the annular energy deposition zone, forming a radial pressure field pointing towards the center of the geometric shape of the annular energy deposition zone.

[0111] S30423: The radial pressure field reaches stress equilibrium in the central region of the annular energy deposition zone, which is transformed into a high-pressure stress concentration zone with the center of the annular energy deposition zone as the focus. The high-pressure stress concentration zone is defined as a local compressive stress field.

[0112] The working principle and beneficial effects of the above technical solution are as follows: In this embodiment, firstly, the non-uniform energy distribution of the annular energy deposition zone induces non-uniform thermoelastic expansion within the silicon ingot; the high-energy region of the annular energy deposition zone undergoes thermal expansion, while the central low-energy region maintains a relatively stable lattice structure; the expansion difference forms a thermoelastic expansion field within the annular energy deposition zone, pointing from the annular region to the central region; secondly, the thermoelastic expansion field is constrained by the geometry of the annular energy deposition zone, and the expansion of the geometrically annular high-energy region is mechanically restricted by the adjacent low-temperature central region. This mechanical restriction transforms the radial thermoelastic expansion into pressure along the annular tangent; the pressure is superimposed within the annular energy deposition zone, forming a radial pressure field pointing towards the center of the annular energy deposition zone's geometry; finally, the radial pressure field reaches stress equilibrium in the central region of the annular energy deposition zone, i.e., transforms into a high-pressure stress concentration zone with the center of the annular energy deposition zone as its focus. This high-pressure stress concentration zone is defined as a local compressive stress field. The process of transforming the stress gradient field into a local compressive stress field in the above solution achieves the technical effect of transforming the non-uniform stress distribution caused by thermal expansion into the stress conversion caused by mechanical restriction, ultimately forming a local compressive stress field. Specifically, the non-uniform energy distribution within the annular energy deposition zone causes non-uniform thermoelastic expansion in different regions of the silicon ingot. High-energy regions experience thermal expansion, while low-energy regions remain relatively stable, thus forming a thermoelastic expansion field pointing towards the central region. This thermoelastic expansion field is constrained by the geometry of the annular energy deposition zone, causing the expansion of the high-energy regions to be mechanically restricted by the low-temperature central region. This mechanical restriction converts the thermoelastic expansion into pressure along the annular tangent. This pressure superimposes within the annular energy deposition zone, forming a radial pressure field pointing towards the center of the annular energy deposition zone's geometry. This radial pressure field reaches stress equilibrium in the central region of the annular energy deposition zone, transforming into a high-pressure stress concentration zone with the center of the annular energy deposition zone as its focal point—a localized compressive stress field.

[0113] In summary, this embodiment effectively transforms the energy distribution differences in the annular energy deposition zone into a local compressive stress field, thereby optimizing and adjusting the stress distribution. This is of great significance for improving the performance and function of materials, such as improving the mechanical properties of materials and promoting crystal growth.

[0114] Example 11: Based on Example 10, the process for forming a radial pressure field pointing towards the geometric center of the annular energy deposition zone provided by this embodiment of the invention specifically includes the following steps:

[0115] S304221: Based on the radial expansion trend of the annular region generated by the thermoelastic expansion field, the radial expansion trend displacement of the annular region is rigidly constrained in the radial direction by the stable lattice structure of the central low-energy region; the rigid constraint forms the strain coordination condition in three-dimensional space, storing the radial expansion strain energy that cannot be released as elastic potential energy.

[0116] S304222: The stored elastic potential energy undergoes an energy state transformation through the material constitutive relation and is redistributed to the tangential dimension where the strain is relatively free according to the principle of minimum potential energy. The energy redistribution process causes the material in the annular region to generate compressive strain along the circumferential direction. The compressive strain is transformed into circumferential compressive stress through the stress-strain relationship. The circumferential compressive stress forms a continuously distributed tangential pressure element in the annular section, and its intensity is proportional to the stored elastic potential energy.

[0117] S304223: Each tangential pressure element generates a normal component force pointing towards the center of curvature in the annular structure. Through stress field superposition calculation, the discrete normal components are integrated into a continuous pressure field within the annular energy deposition zone. The pressure field exhibits a gradient distribution that increases radially from the annular region to the central region, eventually forming a pressure extremum at the geometric center of the deposition zone, thus establishing a complete radial pressure field.

[0118] The working principle and beneficial effects of the above technical solution are as follows: First, based on the radial expansion trend of the annular region generated by the thermoelastic expansion field, the radial expansion trend displacement of the annular region is rigidly constrained by the stable lattice structure of the central low-energy region in the radial direction; the rigid constraint forms strain coordination conditions in three-dimensional space, storing the radial expansion strain energy that cannot be released as elastic potential energy; secondly, the stored elastic potential energy undergoes energy state transformation through the material constitutive relation, and is redistributed to the relatively free tangential dimension according to the principle of minimum potential energy; the energy redistribution process causes the material of the annular region to generate compressive strain along the circumferential direction, and the compressive strain is transformed into circumferential compressive stress through the stress-strain relationship. The circumferential compressive stress forms continuously distributed tangential pressure units in the annular cross section, and its intensity is proportional to the stored elastic potential energy; finally, each tangential pressure unit generates a normal component force pointing towards the center of curvature in the annular structure. Through stress field superposition calculation, these discrete normal components are integrated into a continuous pressure field in the annular energy deposition zone; the pressure field shows a gradient distribution that increases from the annular region to the central region in the radial direction, and finally forms a pressure extremum at the geometric center of the deposition zone, establishing a complete radial pressure field. The above scheme utilizes the radial expansion trend of the annular region caused by thermoelastic expansion. Through the rigid constraint of the stable lattice structure in the central low-energy region, the expansion energy is converted into elastic potential energy and stored in the material. This effectively converts thermal energy into mechanical energy, providing the driving force for energy conversion and distribution. The stored elastic potential energy undergoes energy state transformation through the material's constitutive relations, redistributing itself in the relatively strain-free tangential dimension, causing compressive strain along the circumferential direction in the annular region. This achieves efficient energy transfer and conversion, transforming radial expansion energy into tangential compressive energy. The compressive strain further transforms into circumferential compressive stress, forming continuously distributed tangential pressure units whose strength is proportional to the stored elastic potential energy, ensuring efficient energy distribution and controllable energy intensity. Each tangential pressure unit generates a normal component pointing towards the center of curvature. Through stress field superposition calculations, a continuous pressure field is synthesized, forming a gradient distribution that increases radially from the annular region to the central region. This realizes the transformation from energy distribution to pressure field formation, providing the necessary conditions for the final formation of pressure extrema. Ultimately, a pressure extreme value is formed at the geometric center of the sedimentary zone, establishing a complete radial pressure field; this marks the achievement of the final goal of energy conversion and distribution throughout the entire process, providing a foundation for the further application of annular energy sedimentary zones.

[0119] In summary, this embodiment achieves efficient conversion from thermal energy to mechanical energy, effective energy distribution, and the formation of a pressure field, providing technical support for energy control and utilization in practical applications.

[0120] Example 12: Based on Example 11, the process of integrating discrete normal components into a continuous pressure field within the annular energy deposition zone, as provided in this embodiment of the invention, specifically includes the following steps:

[0121] S3042231: Establish a polar coordinate system with the geometric center of the annular energy deposition zone as the origin, and map each discrete normal component force to the angular position in the polar coordinate system; based on the coordinates of the point of application of the discrete normal component force and the force vector, obtain the projection component of each component force in the radial direction, forming a set of discrete radial force data points.

[0122] S3042232: For discrete radial force data points, linear interpolation based on angular position is used to generate a continuous force density distribution function between adjacent data points, defining the radial force density value at any angular position within the annular energy deposition zone; annular surface integration is performed on the continuous force density distribution function, with the integration process proceeding along the entire circumference of the annular energy deposition zone. The force density value at each angular position is multiplied by the corresponding infinitesimal arc length, and the contributions of all infinitesimal elements are accumulated; a radial pressure distribution function is output, describing the continuous change of pressure along the radial direction.

[0123] The radial pressure distribution function is a continuous scalar function defined on the radial dimension of the annular energy deposition zone. Its function value characterizes the pressure intensity per unit area inside the material. It is established through annular surface integral calculation, with the independent variable being the radial distance from the geometric center of the deposition zone. In terms of function morphology, the pressure intensity is negatively correlated with the radial distance: the function outputs the minimum pressure value when the radial distance approaches the outer edge of the annular region; as the radial distance decreases towards the center point, the function value exhibits a monotonically increasing characteristic and converges to the global maximum at the radial zero point; the derivative of this function is always negative in the domain, ensuring that the pressure gradient direction always points from the outer edge to the center; it fully describes the continuous distribution characteristics of the radial pressure field synthesized by tangential pressure elements inside the annular energy deposition zone, providing a quantitative basis for stress field analysis.

[0124] S3042233: The radial pressure distribution function defines a continuous pressure field within the annular energy deposition zone. The pressure field exhibits a gradient characteristic that increases radially from the annular region to the central region, and reaches the pressure extremum at the geometric center of the deposition zone, thus completing the synthesis from discrete normal components to a continuous pressure field.

[0125] The working principle and beneficial effects of the above technical solution are as follows: First, a polar coordinate system is established with the geometric center of the annular energy deposition zone as the origin, and each discrete normal component is mapped to its angular position in the polar coordinate system. Based on the coordinates of the point of application and the force vector of the discrete normal component, the projection component of each component in the radial direction is obtained, forming a set of discrete radial force data points. Second, linear interpolation based on angular position is applied to the discrete radial force data points to generate a continuous force density distribution function between adjacent data points, defining the radial force density value at any angular position within the annular energy deposition zone. The continuous force density distribution function is subjected to annular surface integration. The integration process is carried out along the entire circumference of the annular energy deposition zone. The force density value at each angular position is multiplied by the corresponding arc length of the infinitesimal element, and the contributions of all infinitesimal elements are accumulated. A radial pressure distribution function is output, which describes the continuous change of pressure in the radial direction. Finally, the radial pressure distribution function defines a continuous pressure field in the annular energy deposition zone. The pressure field exhibits a gradient characteristic that increases radially from the annular region to the central region, and reaches the pressure extremum at the geometric center of the deposition zone, thus completing the synthesis from discrete normal force components to a continuous pressure field. The above scheme transforms the dispersed normal force components into a unified continuous pressure field. By mapping to polar coordinates and acquiring the projected components of radial force data points, it achieves precise positioning of each force component and measurement of its magnitude. Through linear interpolation, the discrete force data points are transformed into a continuous force density distribution function, allowing the radial force density value at any angular position to be defined. By performing annular surface integration on this continuous force density distribution function, the contributions of all infinitesimal elements are integrated, resulting in a radial pressure distribution function that describes the continuous variation of pressure along the radial direction. This not only demonstrates the distribution of pressure within the annular region but also reveals the gradient characteristics of pressure increasing from the annular region to the central region, reaching the pressure extreme value at the geometric center of the annular energy deposition zone.

[0126] Example 13: Based on Example 12, the process of generating a continuous force density distribution function between adjacent data points provided in this embodiment of the invention specifically includes the following steps:

[0127] S30422321: Sort the discrete radial force data points according to their angular positions to form an ordered data sequence; for any two adjacent data points in the data sequence, calculate the angular difference and the radial force value difference;

[0128] S30422322: Based on the angle difference and radial force difference between two adjacent data points, establish a linear relationship between angular position and radial force value; for any angular position between two adjacent data points, calculate the radial force value at any angular position through linear interpolation, that is, allocate the radial force value proportionally according to the relative position of the angle between the two points;

[0129] S30422323: The entire circumference of the annular energy deposition zone is divided into continuous micro-angle intervals. Linear interpolation is applied to each micro-angle interval to calculate the radial force values ​​at all angular positions within the entire circumference, forming a continuous force density distribution function. The force density distribution function defines the radial force density value at any angular position within the annular energy deposition zone.

[0130] The working principle and beneficial effects of the above technical solution are as follows: First, the discrete radial force data points are sorted according to their angular positions to form an ordered data sequence. For any two adjacent data points in the data sequence, the angle difference and radial force value difference are calculated. Second, based on the angle difference and radial force value difference between two adjacent data points, a linear relationship between the angular position and the radial force value is established. For any angular position between two adjacent data points, the radial force value at any angular position is calculated by linear interpolation, that is, the radial force value is proportionally allocated according to the relative position of the angle between the two points. Finally, the entire circumference of the annular energy deposition zone is divided into continuous micro-angle intervals. Linear interpolation is applied to each micro-angle interval to obtain the radial force values ​​at all angular positions within the entire circumference, forming a continuous force density distribution function. The force density distribution function defines the radial force density value at any angular position within the annular energy deposition zone. The above scheme generates a continuous force density distribution function between adjacent data points. It ensures data order by sorting discrete radial force data points according to their angular positions; it determines the trend by calculating the angular difference and radial force difference between any two adjacent data points; based on this, it establishes a linear relationship between angular position and radial force value, enabling prediction of radial force values ​​at any angular position; and it uses linear interpolation to proportionally distribute force values ​​between adjacent data points, resulting in a smoother and more continuous force density distribution. By dividing the entire circumference into continuous micro-angle intervals and applying linear interpolation within each interval, the radial force values ​​at all angular positions within the entire circumference can be obtained. The resulting continuous force density distribution function accurately describes the radial force density value at any angular position within the annular energy deposition zone, thus achieving accurate modeling and prediction of the force field distribution. This provides more accurate and continuous force field distribution data, facilitating higher-precision analysis and applications in fields such as physical simulation and engineering design.

[0131] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of equivalents of this invention, this invention is also intended to include these modifications and variations.

Claims

1. A laser cutting method for silicon ingots, characterized in that, Includes the following steps: When the target depth is scanned along the scanning path using the first beam, the image sequence of crack formation is captured in real time by a high-resolution detector integrated in the optical imaging system; crack width data is extracted from the image sequence, and after filtering and normalization, a continuous distribution of crack width is obtained; the crack width is divided into multiple levels, and the level division is based on the statistical quantile of the width value, from level 1 to level N, where each level corresponds to the degree of potential risk of crack propagation. Based on the crack width level, the corresponding crack control strategy is executed; for cracks that reach the preset crack width level, the phase modulation system of the second beam is activated to move along the scanning path with the first beam in synchronous tracking mode; the spot of the second beam is adjusted to a non-Gaussian distribution by the phase modulator to generate a local compressive stress field. The process of generating a continuous distribution of crack width includes the following steps: The image sequence of crack formation is analyzed frame by frame. By identifying the gray-scale contrast edge between the crack and the matrix material in each frame, the crack outline is located. The center point of the crack outline is connected to generate a crack morphology skeleton that runs through the entire scanning area. Normal section analysis is performed along the crack morphology skeleton to calculate the width value of each section point, thereby outputting a set of original width datasets that correspond one-to-one with the scanning position. The filtering intensity is dynamically adjusted based on the local fluctuations of the data points in the original width dataset to generate a smooth width curve. The smooth width curve is used for scale normalization to obtain the maximum width value in the entire scanning process, and the maximum width value is defined as the reference width. The absolute width value of each point in the smooth width curve is divided by the reference width to convert it into a relative width ratio between 0 and 1, resulting in a standardized crack width continuous distribution curve. Calculate the statistical quantiles of the continuous distribution curve of crack width, divide the width range from 0 to 1 into N continuous intervals, and each interval corresponds to a crack width level; level 1 corresponds to the highest quantile interval, representing the maximum width; Level N corresponds to the lowest quantile interval, representing the minimum width; The grading results directly define the degree of crack propagation risk corresponding to each scan location; The process of generating a local compressive stress field includes the following steps: The preset stress control mapping table is queried according to the crack width level, and each width level is associated with a stress relief requirement; the stress relief requirement is defined as the local compressive stress intensity required to suppress the crack propagation of the level. Based on the stress cancellation requirement, the phase modulation parameters that generate the corresponding light intensity distribution are solved in reverse. The phase modulation parameters are then transmitted to the phase modulator in the second beam path. The phase modulator reconstructs the wavefront of the second beam based on the received phase modulation parameters; it adjusts the original Gaussian wavefront of the second beam into a non-Gaussian wavefront with a central intensity depression feature; the beam with the non-Gaussian wavefront is focused to form a ring-shaped spot at the target depth. The second beam control system acquires motion coordinates along the subsurface scanning path in real time from the first beam control system; based on the motion coordinates and combined with the fixed position offset of the first beam, the second beam calculates its own synchronous tracking coordinates and drives the beam positioning system to move. The annular light spot scans synchronously with the first beam at the target depth; the energy distribution characteristics of the annular light spot induce a local compressive stress field inside the silicon ingot that overlaps with the tensile stress zone generated by the first beam; the compressive stress field counteracts the tensile stress at the crack tip, effectively suppressing crack propagation.

2. The laser cutting method for silicon ingots as described in claim 1, characterized in that, The process of outputting a set of original width datasets that correspond one-to-one with the scan positions includes the following steps: A series of skeleton feature points are extracted from the skeleton lines of the generated crack morphology skeleton at equal intervals, and each feature point corresponds to a scanning position. For each skeleton feature point, calculate its first derivative in the skeleton tangent direction at the skeleton feature point to determine the local skeleton orientation of the skeleton feature point; based on the local skeleton orientation, construct a normal analysis plane perpendicular to the skeleton. The crack profile and the normal analysis plane are spatially intersected to obtain two intersection points, which represent the edge points on both sides of the crack. The Euclidean distance between the two intersection points is measured, which is the normal width value at the current skeleton feature point. The normal width values ​​at all skeleton feature points are arranged and combined according to their corresponding scanning positions to form the original width dataset that is completely synchronized with the scanning trajectory.

3. The laser cutting method for silicon ingots as described in claim 1, characterized in that, The energy distribution characteristics of the annular light spot induce a local compressive stress field within the silicon ingot that overlaps with the tensile stress region generated by the first light beam. This process includes the following steps: By utilizing the central intensity depression characteristic of the annular spot, an annular energy deposition zone is formed at the target depth inside the silicon ingot during the scanning process; the geometry of the annular energy deposition zone is defined by the energy distribution of the annular spot, with the lowest energy in the central region and the highest energy in the annular region. Based on the non-uniform energy distribution of the annular energy deposition zone, a radially inward stress gradient field is induced in the region surrounding the annular energy deposition zone through the absorption response of the material to laser energy. Due to the constraint effect of the annular energy deposition, the stress gradient field is transformed into a local compressive stress field with the center of the deposition zone as the focus. Through synchronous scanning of the second beam and the first beam, the annular energy deposition zone always coincides with the tensile stress zone generated by the Gaussian spot of the first beam in space; this allows the local compressive stress field and the tensile stress zone to superimpose in the same spatial domain, offsetting the tensile stress at the crack tip and effectively suppressing crack propagation.

4. The laser cutting method for silicon ingots as described in claim 3, characterized in that, The process by which a stress gradient field transforms into a local compressive stress field with the center of the sedimentary zone as its focus involves the following steps: The non-uniform energy distribution of the annular energy deposition zone induces non-uniform thermoelastic expansion inside the silicon ingot; the high-energy region of the annular energy deposition zone undergoes thermal expansion, while the central low-energy region maintains a relatively stable lattice structure. The expansion difference forms a thermoelastic expansion field within the annular energy deposition zone, pointing from the annular region to the central region. The thermoelastic expansion field is constrained by the geometry of the annular energy deposition zone. The expansion of the geometric annular high-energy region is mechanically restricted by the adjacent low-temperature central region. The mechanical restriction transforms the radial thermoelastic expansion into pressure along the annular tangent. The pressure is superimposed inside the annular energy deposition zone, forming a radial pressure field pointing towards the center of the geometric shape of the annular energy deposition zone. The radial pressure field reaches stress equilibrium in the central region of the annular energy deposition zone, which transforms into a high-pressure stress concentration zone with the center of the annular energy deposition zone as the focus. The high-pressure stress concentration zone is defined as a local compressive stress field.

5. The laser cutting method for silicon ingots as described in claim 4, characterized in that, The process of forming a radial pressure field pointing towards the geometric center of the annular energy deposition zone includes the following steps: Based on the radial expansion trend of the annular region generated by the thermoelastic expansion field, the radial expansion trend displacement of the annular region is rigidly constrained in the radial direction by the stable lattice structure of the central low-energy region; the rigid constraint forms the strain coordination condition in three-dimensional space, storing the radial expansion strain energy that cannot be released as elastic potential energy. The stored elastic potential energy undergoes an energy state transition through the material constitutive relation and is redistributed to the tangential dimension where the strain is relatively free, according to the principle of minimum potential energy. The energy redistribution process causes the material in the annular region to produce compressive strain along the circumferential direction. The compressive strain is transformed into circumferential compressive stress through the stress-strain relationship. The circumferential compressive stress forms a continuously distributed tangential pressure element in the annular section, and its intensity is proportional to the stored elastic potential energy. Each tangential pressure element generates a normal component force pointing towards the center of curvature in the annular structure; through stress field superposition calculation, the discrete normal components are integrated into a continuous pressure field within the annular energy deposition zone; the pressure field exhibits a gradient distribution that increases radially from the annular region to the central region, and finally forms a pressure extremum at the geometric center of the deposition zone, establishing a complete radial pressure field.

6. The laser cutting method for silicon ingots as described in claim 5, characterized in that, The process of integrating discrete normal components into a continuous pressure field within the annular energy deposition zone includes the following steps: A polar coordinate system is established with the geometric center of the annular energy deposition zone as the origin, and each discrete normal force component is mapped to the angular position in the polar coordinate system. Based on the coordinates of the point of application and the force vector of the discrete normal force component, the projection component of each component in the radial direction is obtained, forming a set of discrete radial force data points. For discrete radial force data points, linear interpolation based on angular position is used to generate a continuous force density distribution function between adjacent data points, defining the radial force density value at any angular position within the annular energy deposition zone; annular surface integration is performed on the continuous force density distribution function, with the integration process carried out along the entire circumferential path of the annular energy deposition zone, multiplying the force density value at each angular position by the corresponding infinitesimal arc length, and accumulating the contributions of all infinitesimal elements; Output a radial pressure distribution function that describes the continuous change of pressure along the radial direction; The radial pressure distribution function defines a continuous pressure field within the annular energy deposition zone. The pressure field exhibits a gradient characteristic that increases radially from the annular region to the central region, and reaches the pressure extremum at the geometric center of the deposition zone, thus completing the synthesis from discrete normal components to a continuous pressure field.

7. The laser cutting method for silicon ingots as described in claim 6, characterized in that, The process of generating a continuous force density distribution function between adjacent data points includes the following steps: The discrete radial force data points are sorted according to their angular positions to form an ordered data sequence; for any two adjacent data points in the data sequence, the angular difference and the radial force difference are calculated. Based on the angle difference and radial force difference between two adjacent data points, a linear relationship between the angular position and the radial force value is established; for any angular position between two adjacent data points, the radial force value at any angular position is calculated by linear interpolation, that is, the radial force value is distributed proportionally according to the relative position of the angle between the two points. The entire circumference of the annular energy deposition zone is divided into continuous micro-angle intervals. Linear interpolation is applied to each micro-angle interval to calculate the radial force values ​​at all angular positions within the entire circumference, forming a continuous force density distribution function. The force density distribution function defines the radial force density value at any angular position within the annular energy deposition zone.

8. The laser cutting method for silicon ingots as described in claim 1, characterized in that, It also includes using an optical imaging system to capture the surface reflection characteristics from a laser source on a silicon ingot, identifying the position of the operating station, which is defined as a local high-reflectivity area in the surface region aligned with the laser source's optical path; based on the coordinate data of the operating station, generating a subsurface scanning path and a target depth, wherein the scanning path is adaptively planned according to the subsurface curvature and crystal orientation, and the target depth is determined by optical penetration calculation as the priority region for crack initiation inside the silicon ingot; the first beam is configured as a Gaussian spot, and its focal point is calibrated to the target depth.

Images