Laser Double-Sided Etching Stress Control Method and System for Quartz Crystal

Abstract

The present invention relates to the technical field of laser etching, and discloses a laser double-sided etching stress control method and system for quartz crystals. The method includes: generating a double-sided complementary etching path based on the initial stress distribution of the quartz crystal. Synchronously controlling the laser energy input on the front and back sides to form a dynamic balance of the double-sided thermal stress field. Real-time obtaining the stress gradient distribution of the etching area based on spectral analysis. According to the deviation amount between the stress gradient and the target threshold, dynamically adjusting the laser processing parameter combination, and starting the topography-stress coupling optimization mode in the final processing stage. By precisely controlling the thermal stress balance and stress gradient distribution in the laser processing process, the present invention can effectively reduce the residual stress of the quartz crystal, optimize its topography and performance, thereby improving the processing accuracy, material stability and device reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of laser etching, and more particularly, to a method and system for controlling the stress in the double-sided laser etching of quartz crystals. Background Art

[0002] Quartz crystals have been widely used in frequency control devices, optical components, precision sensors and other fields due to their excellent piezoelectric properties and thermal stability. With the development of micro-nano manufacturing technology, higher requirements have been put forward for the processing accuracy and structural integrity of quartz crystals. However, in the process of laser etching, due to the anisotropy and thermal physical properties of quartz crystals, single-sided etching often leads to uneven stress distribution, which in turn causes problems such as morphological distortion, crack propagation and residual stress accumulation, seriously affecting the service life and performance stability of the device.

[0003] At present, in the prior art, some studies have tried to reduce the residual stress by optimizing the single-sided laser scanning path or using an auxiliary heat treatment method, but these methods have limitations. For example, although the optimization of the single-sided scanning path can reduce the stress concentration to a certain extent, it cannot completely eliminate the stress gradient caused by unilateral heat accumulation; while the auxiliary heat treatment can relieve the local stress, but its process is complex, energy consumption is high, and it may introduce additional lattice defects. In addition, the non-uniform material removal caused by single-sided etching may also affect the surface quality of the crystal and reduce the reliability of the device.

[0004] Therefore, there is an urgent need to invent a laser double-sided etching stress control technology for quartz crystals to solve the problems that the existing single-sided laser etching and auxiliary heat treatment methods are difficult to effectively control the stress distribution, there are problems such as difficult to eliminate the stress gradient, complex process, high energy consumption and possible introduction of additional lattice defects, resulting in a decline in the surface quality of the crystal and a reduction in the reliability of the device. Summary of the Invention

[0005] In view of this, the present invention proposes a method and system for controlling the stress in the double-sided laser etching of quartz crystals, aiming to solve the problems that the existing single-sided laser etching and auxiliary heat treatment methods are difficult to effectively control the stress distribution, there are problems such as difficult to eliminate the stress gradient, complex process, high energy consumption and possible introduction of additional lattice defects, resulting in a decline in the surface quality of the crystal and a reduction in the reliability of the device.

[0006] The present invention proposes a method for controlling the stress in the double-sided laser etching of quartz crystals, including:

[0007] Generating a double-sided complementary etching path based on the initial stress distribution of the quartz crystal;

[0008] Synchronously controlling the laser energy input on the front and back sides to form a dynamic balance of the double-sided thermal stress field;

[0009] Obtain the stress gradient distribution of the etching area in real time based on spectral analysis;

[0010] According to the deviation between the stress gradient and the target threshold, dynamically adjust the combination of laser processing parameters, and start the topography-stress coupling optimization mode in the final processing stage.

[0011] Furthermore, when synchronously controlling the laser energy input on both sides to form a dynamic balance of the thermal stress fields on both sides, it includes:

[0012] Regulate the trigger timing of the dual laser heads according to the pulse phase difference feedback;

[0013] Dynamically match the energy ratio of the front and back sides based on the symmetry analysis of the thermal stress fields;

[0014] When detecting the relationship between the single-sided thermal accumulation and the preset thermal accumulation, determine whether to automatically start reverse compensation etching.

[0015] Furthermore, when detecting the relationship between the single-sided thermal accumulation and the preset thermal accumulation and determining whether to automatically start reverse compensation etching, it includes:

[0016] Obtain the influence ratio between the depth of the single-sided thermal influence zone and the wafer thickness, and determine the influence ratio as the first index;

[0017] Obtain the distribution characteristics of the temperature field, and determine the distribution characteristics of the temperature field as the second index;

[0018] Obtain the real-time number of times that the stress monitoring data exceeds the dynamic balance interval, and determine it as the third index according to the real-time number of times;

[0019] Based on the relationship between the first index, the second index and the third index, determine the single-sided thermal accumulation evaluation value;

[0020] Based on the relationship between the single-sided thermal accumulation evaluation value and the preset thermal accumulation evaluation value, determine whether to automatically start reverse compensation etching:

[0021] When the single-sided thermal accumulation evaluation value is lower than or equal to the preset thermal accumulation evaluation value, it is determined not to automatically start reverse compensation etching;

[0022] When the single-sided thermal accumulation evaluation value is higher than the preset thermal accumulation evaluation value, it is determined to automatically start reverse compensation etching.

[0023] Furthermore, when obtaining the stress gradient distribution of the etching area in real time based on spectral analysis, it includes:

[0024] Collect the mapping relationship between the Raman frequency shift and the stress value, and construct a real-time topological map of the three-dimensional stress field according to the mapping relationship;

[0025] According to the real-time topological map, identify the geometric characteristic parameters of the stress concentration area.

[0026] Further, when identifying the geometric characteristic parameters of the stress concentration area according to the real-time topology map, it includes:

[0027] Obtain the surface topography data and determine the curvature radius and area ratio of the stress concentration area, wherein the curvature radius is calculated based on the distribution characteristics of the curvature extreme points of the surface contour line, and the area ratio is statistically quantified based on the pixel density of the high-stress area;

[0028] Obtain the spatial distribution law of the lattice distortion vector, decompose the anisotropic components of the lattice distortion based on the Fourier transform algorithm, and establish the mapping relationship between the activation state of the dislocation slip system and the residual stress release path.

[0029] Construct a three-dimensional defect equivalent model based on the mapping relationship between the acoustic wave propagation parameters and the defect morphology characteristics, and calculate the equivalent mechanical depth of the defect in combination with the contact mechanics model;

[0030] Establish the geometric characteristic parameters of the stress concentration area according to the curvature radius and area ratio of the stress concentration area, the mapping relationship between the activation state of the dislocation slip system and the residual stress release path, and the equivalent mechanical depth of the defect.

[0031] Further, when dynamically adjusting the laser processing parameter combination according to the deviation amount between the stress gradient and the target threshold, it includes:

[0032] Obtain the stress gradients on both sides, determine the high-stress side according to the relationship between the stress gradient and the material yield critical value, and reduce the laser power on the high-stress side;

[0033] Adjust the scanning speed according to the ratio of the thermal diffusion rate to the etching rate, and control the effective action depth based on the change of the defocus amount.

[0034] Further, when controlling the effective action depth based on the change of the defocus amount, it includes:

[0035] Establish a non-linear mapping model between the defocus amount and the molten pool depth;

[0036] Dynamically compensate the focal position according to the real-time etching rate;

[0037] Adopt a gradient defocus strategy in the interface transition zone.

[0038] Further, when dynamically compensating the focal position according to the real-time etching rate, it includes:

[0039] Obtain the plasma spectral characteristics of the processing area, and calculate the real-time etching rate based on the preset spectral line intensity - etching depth mapping relationship;

[0040] Establish a dynamic correlation model between the etching rate change rate and the focal offset amount, and the model includes a material response coefficient and a thermal accumulation correction factor;

[0041] When the etching rate is detected to deviate from the set range, a focus position compensation instruction is generated according to the dynamic correlation model;

[0042] Based on the Z-axis motion platform, execute the compensation instruction to keep the laser focal plane dynamically coincident with the material interface.

[0043] Furthermore, when starting the topography-stress coupling optimization mode in the final machining stage, it includes:

[0044] Alternately execute topography refinement scanning and stress release scanning;

[0045] Insert a micro-region remelting process in the region with sudden change of surface curvature;

[0046] Apply prestress compensation according to the mesoscopic topography characteristics, where:

[0047] Obtain the microscopic surface topography data of the target area and calculate the stress distribution based on the photoelastic effect;

[0048] According to the anisotropic etching model dependent on lattice orientation, adjust the local etching energy input to optimize the residual stress field;

[0049] Based on the ultra-short pulse laser-induced oscillation, generate a micro-oscillation field in the local stress concentration area to promote the homogenization of internal stress;

[0050] Based on the multi-level energy gradient etching strategy, set a gradual energy input during the etching path planning to form a gentle stress distribution gradient;

[0051] Combine the equivalent mechanical compensation strategy, calculate the compensation etching path for the local stress concentration area, and adjust the topography structure based on this path to redistribute the stress to the dynamic equilibrium interval.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows: By generating a double-sided complementary etching path, the material removal process becomes more balanced, avoiding the stress concentration problem caused by non-uniform material removal in single-sided processing. Traditional single-sided etching often generates significant stress gradients due to heat accumulation, leading to crystal deformation and even microcrack propagation. However, through the optimization of the double-sided etching path in this method, the material removal amounts on the front and back sides compensate each other, thus significantly reducing the imbalance of stress during the processing and improving the consistency and accuracy of the etching morphology. At the same time, this method adopts synchronous control of the laser energy input on the front and back sides. Through pulse phase regulation and energy ratio matching, a dynamic balance of the double-sided thermal stress field is achieved. Compared with the problem of unilateral heat accumulation in traditional single-sided processing, this method can effectively suppress warping and crack propagation caused by excessive temperature gradients. In addition, this synchronous control strategy can also improve the stability of the etching process, making the thermal influence range of the processing area controllable, thereby reducing structural damage caused by thermal stress concentration and improving the overall processing quality of quartz crystals. In terms of stress monitoring, this method realizes the accurate evaluation of the residual stress in the etching area through real-time stress gradient acquisition based on spectral analysis. Compared with the traditional method of stress detection relying on post-processing means (such as X-ray diffraction or mechanical probe measurement), this scheme uses Raman spectroscopy or other optical monitoring technologies to obtain the stress change situation in real time during the etching process and construct a topological map of the stress gradient distribution. Such a real-time feedback mechanism enables the system to detect stress anomalies at an early stage, thereby timely adjusting the processing parameters to prevent the formation of microcracks or stress concentration areas and improving the yield. In addition, this method also introduces dynamic processing parameter optimization based on stress gradient deviation, that is, by real-time monitoring the deviation between the stress gradient and the target threshold, adaptively adjusting processing parameters such as laser power, scanning speed, and focus position. Compared with the traditional method of fixed processing parameters, this dynamic adjustment strategy can accurately compensate according to the stress state of different regions, realizing the collaborative optimization of material removal uniformity and stress distribution balance, further reducing the processing stress and improving the etching accuracy. Finally, in the final processing stage, this method adopts a morphology-stress coupling optimization mode, alternately performing morphology refinement scanning and stress release scanning, and combining with the micro-region remelting process to make the surface morphology more uniform, while further releasing the residual stress and optimizing the integrity of the crystal structure. Compared with the traditional method of performing additional annealing or polishing correction after single-step processing, this scheme can directly optimize the morphology and stress distribution during the processing, greatly reducing the post-processing process and improving the processing efficiency and product consistency.

[0053] On the other hand, the present application also provides a laser double-sided etching stress control system for quartz crystals, including:

[0054] A dual-field coupling control module, including an energy ratio unit and a phase synchronization unit for the front and back lasers;

[0055] A stress feedback center integrating a multi - spectral joint detection device and a stress field reconstruction processor;

[0056] A dynamic optimization engine configured to perform thermo - mechanical coupling simulation and parameter adaptive matching;

[0057] A cross - scale processing actuator including a macroscopic path driving unit and a microscopic energy modulation component.

[0058] It can be understood that the laser double - sided etching stress control method and system for quartz crystals in the above embodiments of the present invention have the same beneficial effects and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered as limiting the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0060] Figure 1 is a flowchart of a laser double - sided etching stress control method for quartz crystals provided by an embodiment of the present invention;

[0061] Figure 2 is a functional block diagram of a laser double - sided etching stress control system for quartz crystals provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. Hereinafter, the present invention will be described in detail with reference to the drawings and in combination with the embodiments.

[0063] As Figure 1 shown, in some embodiments of the present application, this embodiment provides a laser double - sided etching stress control method for quartz crystals, including:

[0064] Step S100: Generate a double - sided complementary etching path based on the initial stress distribution of the quartz crystal.

[0065] Specifically, divide the high / low stress regions according to the X - ray diffraction data; design a cross - helical scanning trajectory for the high - stress region; and adopt a progressive concentric - circle path for the low - stress region.

[0066] It is understandable that by precisely dividing the high / low stress regions based on X-ray diffraction data, the spatial distribution of residual stress inside the crystal can be obtained. X-ray diffraction technology can provide high-resolution data of the internal stress field of the crystal, enabling the system to determine the stress concentration areas and low-stress regions before processing, providing a basis for subsequent etching path optimization. In this way, corresponding processing strategies can be adopted for different stress distribution regions to avoid the problem of uneven stress release caused by unified path planning. For high-stress regions, this method designs a cross-helical scanning trajectory. Through multi-directional scanning, the laser energy is evenly distributed, and the stress is gradually released in multiple directions. The cross-helical trajectory can effectively reduce local heat accumulation, improve etching uniformity, and reduce the formation of stress concentration points. In addition, due to the continuous transition characteristic of the helical trajectory, compared with the linear scanning method, it can disperse the stress release process more evenly, reduce the risk of inducing microcracks, and improve the structural integrity of the etched area. For low-stress regions, this method adopts a progressive concentric circle path, that is, in the low-stress region, the material is slowly removed by gradually etching from the inside out or from the outside in. Since the low-stress region is less sensitive to the release of residual stress, this milder etching strategy can be adopted to avoid introducing additional stress. The progressive design of the concentric circle path allows for a short cooling time after each layer of material is removed, which helps the slow diffusion of thermal stress, thus ensuring the stability of the etching process and improving the processing quality of the quartz crystal.

[0067] Step S200: Synchronously control the laser energy input on the front and back sides to form a dynamic balance of the double-sided thermal stress field.

[0068] Specifically, when synchronously controlling the laser energy input on the front and back sides to form a dynamic balance of the double-sided thermal stress field, it includes: adjusting the trigger timing of the double laser heads according to the pulse phase difference feedback. Dynamically matching the energy ratio of the front and back sides based on the symmetry analysis of the thermal stress field. When detecting the relationship between the single-sided heat accumulation and the preset heat accumulation, determine whether to automatically start reverse compensation etching.

[0069] Specifically, when detecting the relationship between the single-sided thermal accumulation and the preset thermal accumulation to determine whether to automatically start the reverse compensation etching, it includes: obtaining the influence ratio between the depth of the single-sided thermal influence area and the wafer thickness, and determining the influence ratio as the first index. Obtaining the temperature field distribution characteristics, and determining the temperature field distribution characteristics as the second index. Obtaining the real-time number of times that the stress monitoring data exceeds the dynamic balance interval, and determining it as the third index according to the real-time number of times. Based on the relationship between the first index, the second index, and the third index, determining the single-sided thermal accumulation evaluation value. Based on the relationship between the single-sided thermal accumulation evaluation value and the preset thermal accumulation evaluation value, determining whether to automatically start the reverse compensation etching: when the single-sided thermal accumulation evaluation value is lower than or equal to the preset thermal accumulation evaluation value, it is determined not to automatically start the reverse compensation etching. When the single-sided thermal accumulation evaluation value is higher than the preset thermal accumulation evaluation value, it is determined to automatically start the reverse compensation etching.

[0070] It is understandable that by adjusting the trigger timing of the dual laser heads through pulse phase difference feedback, the time interval between the front and back laser actions can be ensured to be controllable. During the laser processing, heat conduction and heat diffusion have a certain time delay. If the laser pulses on both sides cannot be accurately synchronized, excessive heat accumulation may occur on one side, thereby destroying the thermal stress balance. Therefore, by adjusting the trigger timing through pulse phase difference feedback, the heat affected zones of the double-sided laser action points are heated and cooled synchronously, thereby optimizing the overall thermal stress distribution and improving the etching uniformity and crystal stability. To further optimize the dynamic balance of double-sided laser etching, this method is based on the symmetry analysis of the thermal stress field to dynamically match the energy ratios of the front and back sides. During the actual processing, due to the differences in material thickness, heat conduction characteristics, and local stress states, the energy requirements of the front and back laser are not completely symmetric. Therefore, if a fixed energy ratio is used, the stress balance requirements of all processing areas may not be met. By real-time monitoring the distribution of the thermal stress field and combining finite element analysis or experimental feedback data, the energy ratios of the front and back laser can be dynamically adjusted to match the shapes of the heat affected areas on both sides, thereby reducing local residual stress and improving the etching accuracy and processing quality. When it is detected that the single-sided heat accumulation exceeds the preset range, this method will determine whether to automatically start reverse compensation etching based on multiple indicators. First, by obtaining the influence ratio (the first indicator) between the depth of the single-sided heat affected zone and the wafer thickness, the heat diffusion in the material can be judged; secondly, the temperature field distribution characteristics (the second indicator) are obtained to analyze whether the current temperature gradient tends to be balanced; in addition, the real-time number of times that the stress monitoring data exceeds the dynamic balance interval (the third indicator) is obtained to evaluate the abnormal degree of the stress state during the etching process. These indicators work together to enable the system to quantify the degree of single-sided heat accumulation and adjust the processing strategy accordingly. In the specific decision-making process, this method determines whether to automatically start reverse compensation etching based on the relationship between the single-sided heat accumulation evaluation value and the preset heat accumulation evaluation value. If the single-sided heat accumulation evaluation value is lower than or equal to the preset threshold, it indicates that the current thermal stress distribution is still within the acceptable range and no additional intervention is required; however, if the single-sided heat accumulation evaluation value exceeds the preset threshold, the system will automatically start reverse compensation etching, that is, additional etching energy is added in the relatively low heat accumulation area to balance the heat input. This strategy ensures the continuous dynamic balance of the thermal field during the etching process, helps to reduce defects such as warping and cracking caused by single-sided heat accumulation, improves the etching accuracy, and guarantees the structural stability of the quartz crystal and the reliability of the final device.

[0071] It can be seen that during the laser double-sided etching process, by synchronously controlling the laser energy input on both sides, a dynamic balance is formed in the double-sided thermal stress field, which can effectively reduce the problem of uneven stress gradient caused by unilateral thermal accumulation. Traditional single-sided etching easily causes severe fluctuations in the local temperature field, resulting in large residual stresses inside the crystal, thereby affecting the processing accuracy and material stability. However, this method realizes the dynamic balance of thermal stress by precisely regulating the triggering timing and energy matching of the lasers on both sides, making the entire processing process more stable, reducing the warping and deformation of the crystal, and improving the reliability of the final device. By adjusting the triggering timing of the two laser heads through pulse phase difference feedback, this method can accurately control the action timing of laser pulses on both sides, making the thermal input highly synchronous. This way avoids the problem of uneven heat diffusion caused by asynchronous laser action timing, thereby reducing the local thermal stress gradient. In addition, based on the symmetry analysis of the thermal stress field, this method dynamically matches the energy ratios on both sides, further optimizing the thermal field distribution. Since the thermal conduction characteristics of quartz crystals vary in different regions, a single fixed energy ratio may not meet the stress balance requirements of all regions. By real-time analyzing the symmetry of the thermal stress field and dynamically adjusting the laser energy input on both sides according to the thermal accumulation during the etching process, local stress concentration can be effectively reduced, the processing accuracy can be improved, and the risk of microcracks that may occur during the processing can be reduced. When it is detected that the unilateral thermal accumulation exceeds the preset range, this method can decide whether to automatically start reverse compensation etching based on multiple evaluation indicators to ensure the continuous balance of thermal input during the processing. By monitoring the depth of the unilateral thermal influence zone, the distribution characteristics of the temperature field, and the stress fluctuation conditions, the system can judge in real time whether additional compensation etching is required. If the thermal accumulation exceeds the safety threshold, the etching energy on the other side is automatically increased to rebalance the thermal field. This intelligent adjustment strategy not only improves the stability of the processing but also reduces the need for human intervention, making the entire etching process more intelligent and efficient, thereby significantly improving the quality and consistency of quartz crystal laser processing.

[0072] Step S300: Based on spectral analysis, the stress gradient distribution in the etching area is obtained in real time.

[0073] Specifically, when obtaining the stress gradient distribution in the etching area based on spectral analysis, it includes: collecting the mapping relationship between Raman frequency shift and stress value, and constructing a real-time topology map of the three-dimensional stress field according to the mapping relationship. According to the real-time topology map, the geometric feature parameters of the stress concentration area are identified.

[0074] Specifically, when identifying the geometric characteristic parameters of the stress concentration area according to the real-time topology map, it includes: obtaining the surface topography data and determining the curvature radius and area proportion of the stress concentration area, where the curvature radius is calculated based on the distribution characteristics of the curvature extreme points of the surface contour line, and the area proportion is statistically quantified based on the pixel density of the high-stress area. Obtaining the spatial distribution law of the lattice distortion vector, decomposing the anisotropic components of the lattice distortion based on the Fourier transform algorithm, and establishing the mapping relationship between the activation state of the dislocation slip system and the residual stress release path. Constructing a three-dimensional defect equivalent model based on the mapping relationship between the acoustic wave propagation parameters and the defect morphology characteristics, and calculating the equivalent mechanical depth of the defect in combination with the contact mechanics model. Establishing the geometric characteristic parameters of the stress concentration area according to the curvature radius and area proportion of the stress concentration area, the mapping relationship between the activation state of the dislocation slip system and the residual stress release path, and the equivalent mechanical depth of the defect.

[0075] It can be understood that by collecting the mapping relationship between the Raman shift amount and the stress value, the stress information can be accurately extracted from the spectral data of the etching area. The Raman spectroscopy analysis technology can reflect the change of the internal stress of the material by detecting the frequency shift change of the light. Therefore, by establishing the mapping relationship between the Raman shift and the stress value, the distribution of the stress field during the etching process can be monitored in real time, and these data can be used to generate a real-time topology map of the three-dimensional stress field, making the stress distribution of the etching area visible and providing accurate data support for subsequent processing adjustment. Using the real-time topology map, this method can identify the geometric characteristic parameters of the stress concentration area. During the etching process, due to the heat conduction and the non-uniformity of material removal, stress may concentrate in some areas, forming a stress concentration area. By analyzing the three-dimensional distribution of the stress field in real time, these stress concentration areas can be quickly located and their geometric characteristics, such as the curvature radius and area proportion, can be identified. The curvature radius is calculated based on the distribution characteristics of the curvature extreme points of the surface contour line, which can reflect the shape characteristics of the stress concentration area; while the area proportion is quantified by statistically counting the pixel density of the high-stress area, which can evaluate the area size of the stress concentration area, thus providing a basis for subsequent etching parameter adjustment. When analyzing the stress concentration area, in addition to the geometric characteristics, the spatial distribution law of the lattice distortion vector also plays an important role. By decomposing the anisotropic components of the lattice distortion based on the Fourier transform algorithm, the strain information inside the crystal can be obtained, and further the mapping relationship between the activation state of the dislocation slip system and the residual stress release path can be established. This analysis method can reveal the dislocation movement and stress release mechanism inside the crystal, providing theoretical support for understanding stress concentration and defect formation. At the same time, the mapping relationship between the acoustic wave propagation parameters and the defect morphology characteristics combined with the contact mechanics model can help construct a three-dimensional defect equivalent model to quantitatively analyze the depth and nature of the defect, further understanding and predicting the possible defects during the etching process.

[0076] It can be seen that the geometric characteristic parameters of the stress concentration area can be comprehensively evaluated by the curvature radius, area ratio, activation state of the dislocation slip system, and the equivalent mechanical depth of the defect. These parameters can comprehensively describe the morphological characteristics and mechanical state of the stress concentration area, providing an important basis for stress regulation and optimization in the subsequent etching process. Through this series of analysis methods, the stress gradient distribution during the etching process can be accurately grasped, so as to effectively adjust the laser processing parameters, reduce stress concentration, avoid the occurrence of cracks or deformation, and ultimately improve the processing accuracy and reliability of the quartz crystal.

[0077] Step S400: Dynamically adjust the laser processing parameter combination according to the deviation amount between the stress gradient and the target threshold, and start the morphology-stress coupling optimization mode in the final processing stage.

[0078] Specifically, when dynamically adjusting the laser processing parameter combination according to the deviation amount between the stress gradient and the target threshold, it includes: obtaining the stress gradients on both sides, determining the high-stress side according to the relationship between the stress gradient and the material yield critical value, and reducing the laser power on the high-stress side. Adjust the scanning speed according to the ratio of the heat diffusion rate to the etching rate, and control the effective action depth based on the change of the defocus amount.

[0079] Specifically, when controlling the effective action depth based on the change of the defocus amount, it includes: establishing a non-linear mapping model between the defocus amount and the molten pool depth. Dynamically compensate the focal position according to the real-time etching rate. Adopt a gradual defocus strategy in the interface transition area.

[0080] Specifically, when dynamically compensating the focal position according to the real-time etching rate, it includes: obtaining the plasma spectral characteristics of the processing area, and calculating the real-time etching rate based on the preset spectral line intensity-etching depth mapping relationship. Establish a dynamic correlation model between the etching rate change rate and the focal point offset amount, and the model includes a material response coefficient and a heat accumulation correction factor. When it is detected that the etching rate deviates from the set range, generate a focal position compensation instruction according to the dynamic correlation model. Execute the compensation instruction based on the Z-axis motion platform to keep the laser focal plane dynamically coincident with the material interface.

[0081] Specifically, when starting the topography-stress coupling optimization module in the final processing stage, it includes: alternately performing topography refinement scanning and stress release scanning. Inserting a micro-region remelting process in the regions where the surface curvature changes abruptly. Applying prestress compensation according to the mesoscopic topography features, where: obtaining the microscopic surface topography data of the target region and calculating the stress distribution based on the photoelastic effect. Adjusting the local etching energy input according to the anisotropic etching model dependent on the lattice orientation to optimize the residual stress field. Generating a micro-oscillation field in the local stress concentration region based on ultrashort pulse laser-induced oscillation to promote the homogenization of internal stress. Based on the multi-level energy gradient etching strategy, setting a gradual energy input during the etching path planning to form a gentle stress distribution gradient. Combining with the equivalent mechanical compensation strategy, calculating the compensation etching path for the local stress concentration region and adjusting the topography structure based on this path so that the stress redistributes to the dynamic equilibrium range.

[0082] It is understandable that during the etching process, by monitoring the stress gradient in real time and comparing it with the target threshold, the high-stress region is determined based on the relationship between the stress gradient and the material yield critical value. The laser power in the high-stress region will be dynamically reduced to prevent further stress accumulation in this region. This adjustment method helps to avoid stress concentration caused by local overheating, thereby reducing the crack risk of the crystal material. At the same time, the scanning speed is also adjusted according to the ratio of the heat diffusion rate to the etching rate to ensure the effective dispersion of heat and avoid uneven temperature distribution during the etching process. Secondly, this technology controls the effective action depth through the change of defocus amount, providing more precise depth control for the etching process. By establishing a non-linear mapping model between the defocus amount and the molten pool depth, the focal position can be adjusted in real time to ensure that the effective action depth of the laser energy in the material always remains in the optimal state. This dynamic adjustment mechanism is particularly crucial during the etching process because it can continuously compensate for the focal position according to the change of the etching rate, preventing uneven etching depth caused by the deviation of the focal position. To meet the special requirements of the interface transition region, a gradient defocus strategy is also proposed to further ensure efficient and uniform etching on different layers of the material. During the process of real-time compensating the focal position, the acquisition of plasma spectral characteristics becomes the key. By obtaining the plasma spectral data of the processing area and based on the mapping relationship between the spectral line intensity and the etching depth, the real-time etching rate can be accurately calculated. There is a dynamic correlation between the change rate of the etching rate and the focal offset amount. By establishing a dynamic correlation model, the focal offset can be precisely controlled, and when the etching rate deviates from the set range, a compensation instruction is generated. Finally, based on the Z-axis motion platform, the compensation instruction is executed to achieve the dynamic coincidence of the laser focal plane and the material interface, ensuring the depth and precision consistency during the etching process. In addition, in the final processing stage, this technology further optimizes the processing result of the quartz crystal by starting the topography-stress coupling optimization mode. In this mode, by alternately performing topography refinement scanning and stress release scanning, not only can the surface topography be finely repaired, but also the stress concentration caused by etching can be effectively alleviated. In the region where the surface curvature changes suddenly, a micro-area remelting process can also be inserted to eliminate possible stress concentration and enhance the surface quality. These strategies effectively improve the surface accuracy and stress distribution of the quartz crystal, thereby enhancing its structural stability. Finally, by applying prestress compensation according to the mesoscopic topography characteristics, the technology further enhances the fine control of the etching process. By obtaining the microscopic surface topography data of the target area and calculating the stress distribution based on the photoelastic effect, the stress change inside the material can be accurately grasped. Using the anisotropic etching model dependent on lattice orientation, the local etching energy input can be adjusted to optimize the residual stress field.In addition, the combination of ultrashort pulsed laser-induced oscillation and multi-level energy gradient etching strategies can effectively generate a micro-oscillation field, promote the homogenization of internal stress, form a gentle stress distribution gradient, and finally calculate and compensate the etching path through the equivalent mechanical compensation strategy to achieve stress redistribution and ensure that the quartz crystal maintains a dynamic equilibrium state after processing.

[0083] It can be seen that by obtaining the stress gradients on both sides and comparing them with the critical value of material yield, the high-stress area can be accurately determined, and the laser power can be adjusted according to the stress change, thus effectively avoiding the stress concentration caused by local heat accumulation. In addition, by adjusting the ratio of the heat diffusion rate to the etching rate, the heat distribution during the laser etching process is ensured to be uniform, avoiding material deformation or damage caused by local overheating. Therefore, this solution effectively reduces stress non-uniformity and heat accumulation during the etching process, thereby improving the stability and reliability of the processed quartz crystal. Secondly, by controlling the effective action depth through the change of defocus amount, this technical solution further improves the processing accuracy. Dynamically compensating the focal position can ensure the highly accurate docking of the laser focus and the material interface during the etching process, avoiding the depth inconsistency caused by focal shift. By adopting a gradual defocus strategy in the interface transition area, uniform processing of the transition area is ensured, reducing possible damage or non-uniform treatment on the material surface. This control method can better adapt to the complex changes in different processing areas, especially for precision etching tasks with high requirements, and its operability and effect are more obvious. In addition, during the dynamic adjustment process, the real-time monitoring and compensation of the etching rate further enhance the adaptability and stability of this technology. By obtaining the plasma spectral characteristics of the processing area in real time and dynamically compensating the focal position according to the etching rate, the fluctuation of the etching rate can be effectively prevented from affecting the processing quality. At the same time, the established dynamic correlation model between the change rate of the etching rate and the focal shift amount makes the compensation of the focal position more accurate, providing a guarantee for the high-precision processing of quartz crystals. By executing the compensation command of the Z-axis motion platform, the dynamic coincidence of the laser focal plane and the material interface is further ensured, effectively improving the processing accuracy and consistency. At the same time, when starting the morphology-stress coupling optimization mode in the final processing stage, this technical solution effectively avoids cracks or structural instability caused by stress concentration or irregular surface morphology by alternately executing the strategies of morphology refinement scanning and stress release scanning. In addition, inserting the micro-region remelting process can further repair the area with sudden change of surface curvature and improve the overall quality of the quartz crystal surface. These operations make the surface of the finally processed material not only smoother, but also the stress is effectively balanced, further improving its service life and performance. Finally, by applying prestress compensation according to the mesoscopic morphology characteristics and calculating the stress distribution in combination with the photoelastic effect, this technical solution can optimize the residual stress field of the material in real time during the processing. By adjusting the local etching energy input to optimize the stress distribution and combining the ultrashort pulse laser-induced oscillation and multi-level energy gradient etching strategies, the local stress area is promoted to be uniform, thus avoiding the stress concentration problem existing in the traditional laser etching method. Through the equivalent mechanical compensation strategy, the compensation path can be accurately calculated, and by adjusting the morphology structure, it is ensured that the final stress is within the dynamic balance range, optimizing the overall performance and reliability of the quartz crystal.

[0084] In the above embodiments, through the generation of the double-sided complementary etching path, the material removal process is made more balanced, avoiding the stress concentration problem caused by non-uniform material removal in single-sided processing. Traditional single-sided etching often generates a significant stress gradient due to heat accumulation, leading to crystal deformation and even microcrack propagation. However, through the optimization of the double-sided etching path in this method, the material removal amounts on the front and back sides compensate each other, thus significantly reducing the stress imbalance during the processing and improving the consistency and accuracy of the etching morphology. At the same time, this method adopts synchronous control of the laser energy input on the front and back sides. Through pulse phase regulation and energy ratio matching, the double-sided thermal stress field reaches a dynamic balance. Compared with the problem of unilateral heat accumulation in traditional single-sided processing, this method can effectively suppress warping and crack propagation caused by excessive temperature gradient. In addition, this synchronous control strategy can also improve the stability of the etching process, make the thermal influence range of the processing area controllable, thereby reducing the structural damage caused by thermal stress concentration and improving the overall processing quality of the quartz crystal. In terms of stress monitoring, this method realizes the accurate evaluation of the residual stress in the etching area through real-time stress gradient acquisition based on spectral analysis. Compared with the traditional method of stress detection relying on post-processing means (such as X-ray diffraction or mechanical probe measurement), this scheme uses Raman spectroscopy or other optical monitoring technologies to obtain the stress change situation in real time during the etching process and construct a topological map of the stress gradient distribution. Such a real-time feedback mechanism enables the system to detect stress anomalies at an early stage, thereby timely adjusting the processing parameters to prevent the formation of microcracks or stress concentration areas and improving the yield. In addition, this method also introduces dynamic processing parameter optimization based on the stress gradient deviation, that is, by real-time monitoring the deviation between the stress gradient and the target threshold, adaptively adjusting processing parameters such as laser power, scanning speed, and focus position. Compared with the traditional method of fixed processing parameters, this dynamic adjustment strategy can accurately compensate according to the stress state of different regions, realizing the coordinated optimization of material removal uniformity and stress distribution balance, further reducing the processing stress and improving the etching accuracy. Finally, in the final processing stage, this method adopts a morphology-stress coupling optimization mode, alternately performing morphology refinement scanning and stress release scanning, and combining the micro-region remelting process to make the surface morphology more uniform, while further releasing the residual stress and optimizing the integrity of the crystal structure. Compared with the traditional method of performing additional annealing or polishing correction after single-step processing, this scheme can directly optimize the morphology and stress distribution during the processing, greatly reducing the post-processing process and improving the processing efficiency and product consistency.

[0085] In another preferred manner based on the above embodiments, as Figure 2 shown, this embodiment provides a laser double-sided etching stress control system for quartz crystals, including:

[0086] A dual-field coupling control module, including an energy ratio unit and a phase synchronization unit for the front and back lasers.

[0087] A stress feedback center integrating a multi-spectral joint detection device and a stress field reconstruction processor.

[0088] A dynamic optimization engine configured to perform thermal-mechanical coupling simulation and parameter adaptive matching.

[0089] A cross-scale processing actuator including a macroscopic path driving unit and a microscopic energy modulation component.

[0090] It is understood that the laser double-sided etching stress control method and system for quartz crystals in the above embodiments of the present invention have the same beneficial effects and will not be elaborated here.

[0091] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0093] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one process or Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps of the functions specified in one block or a plurality of blocks.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A laser double-sided etching stress control method for quartz crystal, characterized in that: include: Generate double-sided complementary etching paths based on the initial stress distribution of the quartz crystal; Synchronously control the laser energy input on the front and back sides to achieve a dynamic balance of thermal stress fields on both sides; Obtain stress gradient distribution in the etched area in real time based on spectral analysis; According to the deviation between the stress gradient and the target threshold, the laser processing parameter combination is dynamically adjusted, and the morphology-stress coupling optimization mode is started in the final processing stage; Synchronously controlling the laser energy input on the front and back sides to achieve a dynamic balance of the thermal stress field on both sides includes: Adjust the triggering timing of the dual laser heads according to the pulse phase difference feedback; Dynamically match the front and back energy ratio based on the symmetry analysis of the thermal stress field; When the relationship between the single-side heat accumulation and the preset heat accumulation is detected, determining whether to automatically start the reverse compensation etching; According to the deviation between the stress gradient and the target threshold, the laser processing parameter combination is dynamically adjusted, including: Obtain stress gradients on both sides, determine the high stress side based on the relationship between stress gradient and material yield critical value, and reduce the laser power on the high stress side; The scanning speed is adjusted according to the ratio of the thermal diffusion rate to the etching rate, and the effective action depth is controlled based on the change in the defocus amount.

2. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: When the relationship between the single-side heat accumulation and the preset heat accumulation is detected, determining whether to automatically start the reverse compensation etching includes: Obtaining an influence ratio between the depth of the heat-affected zone on one side and the thickness of the wafer, and determining the influence ratio as a first indicator; Acquiring temperature field distribution characteristics, and determining the temperature field distribution characteristics as a second indicator; Obtain the real-time number of times that the stress monitoring data exceeds the dynamic balance interval, and determine the third indicator based on the real-time number; Determine a single-side heat accumulation evaluation value based on the relationship among the first index, the second index, and the third index; Based on the relationship between the single-side thermal accumulation evaluation value and the preset thermal accumulation evaluation value, determine whether to automatically start the reverse compensation etching: When the single-side heat accumulation evaluation value is lower than or equal to the preset heat accumulation evaluation value, it is determined not to automatically start the reverse compensation etching; When the single-side heat accumulation evaluation value is higher than a preset heat accumulation evaluation value, it is determined to automatically start the reverse compensation etching.

3. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: When the stress gradient distribution of the etched area is obtained in real time based on spectral analysis, it includes: Collect the mapping relationship between Raman frequency shift and stress value, and construct a real-time topological map of the three-dimensional stress field based on the mapping relationship; According to the real-time topology map, the geometric characteristic parameters of the stress concentration area are identified.

4. The laser double-sided etching stress control method for quartz crystal according to claim 3, characterized in that: According to the real-time topology map, the geometric characteristic parameters of the stress concentration area are identified, including: Obtain surface topography data and determine the radius of curvature and area ratio of the stress concentration area, where the radius of curvature is calculated based on the distribution characteristics of the extreme points of curvature of the surface contour lines, and the area ratio is quantified based on the statistical pixel density of the high stress area; Obtain the spatial distribution law of the lattice distortion vector, decompose the anisotropic component of the lattice distortion based on the Fourier transform algorithm, and establish the mapping relationship between the activation state of the dislocation slip system and the residual stress release path A three-dimensional defect equivalent model is constructed based on the mapping relationship between the acoustic wave propagation parameters and the defect morphological characteristics, and the equivalent mechanical depth of the defect is calculated in combination with the contact mechanics model. The geometric characteristic parameters of the stress concentration area are established according to the curvature radius and area ratio of the stress concentration area, the mapping relationship between the activation state of the dislocation slip system and the residual stress release path, and the equivalent mechanical depth of the defect.

5. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: When controlling the effective depth of action based on the change in defocus, it includes: Establish a nonlinear mapping model between defocus amount and molten pool depth; Dynamically compensate the focus position according to the real-time etching rate; A gradual defocusing strategy is adopted in the interface transition zone.

6. The laser double-sided etching stress control method for quartz crystal according to claim 5, characterized in that: When the focus position is dynamically compensated according to the real-time etch rate, it includes: Obtain the plasma spectrum characteristics of the processing area and calculate the real-time etching rate based on the preset spectral line intensity-etching depth mapping relationship; Establishing a dynamic correlation model between the etching rate change rate and the focus offset, wherein the model includes a material response coefficient and a heat accumulation correction factor; When it is detected that the etching rate deviates from the set range, a focus position compensation instruction is generated according to the dynamic correlation model; Compensation instructions are executed based on the Z-axis motion platform to keep the laser focal plane and the material interface dynamically coincident.

7. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: When the morphology-stress coupling optimization mode is activated in the final processing stage, it includes: Performing topography refinement scans and stress release scans alternately; Insert a micro-area remelting process in the area where the surface curvature changes suddenly; Prestress compensation is applied according to the mesoscopic morphological characteristics, where: Obtain microscopic surface morphology data of the target area and calculate stress distribution based on the photoelastic effect; According to the lattice orientation-dependent anisotropic etching model, the local etching energy input is adjusted to optimize the residual stress field; Based on ultrashort pulse laser-induced oscillation, a micro-oscillation field is generated in the local stress concentration area to promote the homogenization of internal stress; Based on the multi-level energy gradient etching strategy, a gradual energy input is set during etching path planning to form a moderate stress distribution gradient; Combined with the equivalent mechanical compensation strategy, the compensation etching path of the local stress concentration area is calculated, and the morphology structure is adjusted based on the path so that the stress is redistributed to the dynamic equilibrium range.

8. A laser double-sided etching stress control system for quartz crystal, applicable to a laser double-sided etching stress control method for quartz crystal as claimed in any one of claims 1 to 7, characterized in that: include: A dual-field coupling control module, including an energy ratio unit and a phase synchronization unit for the front and back lasers; Stress feedback center, integrating multi-spectral joint detection device and stress field reconstruction processor; A dynamic optimization engine configured to perform thermal-mechanical coupling simulation and parameter adaptive matching; A cross-scale processing actuator includes a macroscopic path driving unit and a microscopic energy modulation component.

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