Laser double-sided etching stress control method and system for quartz crystal

Abstract

The invention relates to the technical field of laser etching, and discloses a laser double-sided etching stress control method and system for a quartz crystal, and the method comprises the steps: generating a double-sided complementary etching path based on the initial stress distribution of the quartz crystal; and front and back laser energy input is synchronously controlled, so that a double-sided thermal stress field forms dynamic balance. And obtaining the stress gradient distribution of the etching area in real time based on spectral analysis. And according to the deviation value of the stress gradient and a target threshold value, a laser processing parameter combination is dynamically adjusted, and a morphology-stress coupling optimization mode is started in a final processing stage. By accurately controlling the thermal stress balance and the stress gradient distribution in the laser processing process, the residual stress of the quartz crystal can be effectively reduced, and the shape and the performance of the quartz crystal are optimized, so that the processing precision, the material stability and the device reliability are improved.

Description

Technical Field

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

[0002] Quartz crystals have been widely used in frequency-controlled 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 are placed on the processing accuracy and structural integrity of quartz crystals. However, during the laser etching process, due to the anisotropy and thermophysical 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 existing technology, some studies have attempted to reduce residual stress by optimizing the single-sided laser scanning path or using auxiliary heat treatment, but these methods have limitations. For example, although single-sided scanning path optimization can reduce stress concentration to a certain extent, it cannot completely eliminate the stress gradient caused by unilateral heat accumulation; and although auxiliary heat treatment can relieve local stress, its process is complex, energy-intensive, and may introduce additional lattice defects. In addition, the non-uniform material removal caused by single-sided etching may also affect the crystal surface quality 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 stress distribution, have difficulties in eliminating stress gradients, complex processes, high energy consumption, and may introduce additional lattice defects, resulting in reduced crystal surface quality and reduced device reliability. Summary of the invention

[0005] In view of this, the present invention proposes a laser double-sided etching stress control method and system for quartz crystals, aiming to solve the problems that the existing single-sided laser etching and auxiliary heat treatment methods are difficult to effectively control stress distribution, have difficulties in eliminating stress gradients, complex processes, high energy consumption, and may introduce additional lattice defects, resulting in reduced crystal surface quality and reduced device reliability.

[0006] The present invention proposes a laser double-sided etching stress control method for quartz crystal, comprising:

[0007] Generate double-sided complementary etching paths based on the initial stress distribution of the quartz crystal;

[0008] Synchronously control the laser energy input on the front and back sides to achieve a dynamic balance of thermal stress fields on both sides;

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

[0010] 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.

[0011] Furthermore, when the laser energy input on the front and back sides is synchronously controlled so that the thermal stress field on both sides forms a dynamic balance, it includes:

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

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

[0014] When the relationship between the single-side heat accumulation and the preset heat accumulation is detected, it is determined whether to automatically start the reverse compensation etching.

[0015] Further, 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:

[0016] 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;

[0017] Acquiring temperature field distribution characteristics, and determining the temperature field distribution characteristics as a second indicator;

[0018] 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;

[0019] Determine a single-side heat accumulation evaluation value based on the relationship among the first index, the second index, and the third index;

[0020] 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:

[0021] 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;

[0022] 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.

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

[0024] 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;

[0025] According to the real-time topology map, the geometric characteristic parameters of the stress concentration area are identified.

[0026] Furthermore, according to the real-time topology map, the geometric characteristic parameters of the stress concentration area are identified, including:

[0027] 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;

[0028] The spatial distribution law of the lattice distortion vector is obtained, the anisotropic component of the lattice distortion is decomposed based on the Fourier transform algorithm, and the mapping relationship between the activation state of the dislocation slip system and the residual stress release path is established.

[0029] 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.

[0030] 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.

[0031] Furthermore, according to the deviation between the stress gradient and the target threshold, the laser processing parameter combination is dynamically adjusted, including:

[0032] 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;

[0033] 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.

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

[0035] Establish a nonlinear mapping model between defocus amount and molten pool depth;

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

[0037] A gradual defocusing strategy is adopted in the interface transition zone.

[0038] Further, when the focus position is dynamically compensated according to the real-time etching rate, it includes:

[0039] 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;

[0040] 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;

[0041] 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;

[0042] Compensation instructions are executed based on the Z-axis motion platform to keep the laser focal plane and the material interface dynamically coincident.

[0043] Furthermore, when the morphology-stress coupling optimization mode is started in the final processing stage, it includes:

[0044] Performing topography refinement scans and stress release scans alternately;

[0045] Insert a micro-area remelting process in the area where the surface curvature changes suddenly;

[0046] Prestress compensation is applied according to the mesoscopic morphological characteristics, where:

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

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

[0049] 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;

[0050] 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;

[0051] 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.

[0052] Compared with the prior art, the beneficial effect of the present invention is that: by generating a 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 produces significant stress gradients due to heat accumulation, leading to crystal deformation and even microcrack expansion. The present method optimizes the double-sided etching path so that the material removal amounts on the front and back sides compensate each other, thereby significantly reducing the stress imbalance during the processing process and improving the consistency and accuracy of the etching morphology. At the same time, the present method adopts synchronous control of the front and back laser energy input, and achieves dynamic balance of the double-sided thermal stress field through pulse phase regulation and energy ratio matching. Compared with the problem of unilateral heat accumulation in traditional single-sided processing, the present method can effectively suppress warping and crack expansion caused by excessive temperature gradient. In addition, the synchronous control strategy can also improve the stability of the etching process, make the heat-affected range of the processing area controllable, thereby reducing the structural damage caused by thermal stress concentration and improving the overall processing quality of quartz crystals. In terms of stress monitoring, this method achieves accurate evaluation of residual stress in the etching area by acquiring real-time stress gradients based on spectral analysis. Compared with the traditional method of stress detection that relies on post-processing means (such as X-ray diffraction or mechanical probe measurement), this solution uses Raman spectroscopy or other optical monitoring technologies to obtain stress changes in real time during the etching process and construct a stress gradient distribution topology map. Such a real-time feedback mechanism enables the system to detect stress anomalies at an early stage, thereby adjusting processing parameters in time to prevent the formation of microcracks or stress concentration areas and improve the yield rate. In addition, this method also introduces dynamic processing parameter optimization based on stress gradient deviation, that is, by real-time monitoring of 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 fixing processing parameters, this dynamic adjustment strategy can accurately compensate according to the stress state of different regions, achieve coordinated optimization of material removal uniformity and stress distribution balance, further reduce processing stress, and improve etching accuracy. Finally, in the final processing stage, this method adopts the morphology-stress coupling optimization mode, alternately performs morphology refinement scanning and stress release scanning, and combines the micro-area remelting process to make the surface morphology more uniform, while further releasing residual stress and optimizing the integrity of the crystal structure. Compared with the traditional single-step processing method with subsequent additional annealing or polishing correction, this solution can directly optimize the morphology and stress distribution during the processing process, greatly reduce the post-processing process, and improve 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 a quartz crystal, comprising:

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

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

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

[0057] A cross-scale processing actuator includes 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 crystal in the above-mentioned embodiments of the present invention have the same beneficial effects, which will not be described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

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

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

[0062] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

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

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

[0065] Specifically, high / low stress areas are divided according to X-ray diffraction data; a cross-spiral scanning trajectory is designed for the high stress area; and a progressive concentric circle path is used for the low stress area.

[0066] It is understandable that the spatial distribution of residual stress inside the crystal is obtained by accurately dividing the high / low stress areas based on X-ray diffraction data. X-ray diffraction technology can provide high-resolution data of the stress field inside the crystal, enabling the system to determine the stress concentration area and the low stress area before processing, providing a basis for the subsequent etching path optimization. In this way, corresponding processing strategies can be adopted for different stress distribution areas to avoid the problem of uneven stress release caused by unified path planning. For high stress areas, this method designs a cross-spiral scanning trajectory, which evenly distributes the laser energy through multi-directional scanning and promotes the gradual release of stress in multiple directions. The cross-spiral 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 characteristics of the spiral trajectory, the stress release process can be more evenly dispersed than the linear scanning method, reducing the risk of inducing microcracks and improving the structural integrity of the etching area. For low stress areas, this method adopts a progressive concentric circle path, that is, in the low stress area, the material is slowly removed by gradually etching from the inside to the outside or from the outside to the inside. Since low stress areas are less sensitive to residual stress release, this gentler etching strategy can be used to avoid additional stress introduction. The progressive design of the concentric circle path allows a short cooling time after each layer of material is removed, which helps to slowly diffuse thermal stress, thereby ensuring the stability of the etching process and improving the processing quality of quartz crystals.

[0067] Step S200, synchronously controlling the laser energy input on the front and back surfaces to achieve a dynamic balance of the thermal stress fields on both surfaces.

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

[0069] Specifically, when the relationship between the single-sided heat accumulation and the preset heat accumulation is detected, it is determined whether to automatically start the reverse compensation etching, including: obtaining the influence ratio between the depth of the single-sided heat-affected zone and the thickness of the chip, and determining the influence ratio as the first indicator. Obtain the temperature field distribution characteristics, and determine the temperature field distribution characteristics as the second indicator. Obtain the real-time number of times that the stress monitoring data exceeds the dynamic equilibrium interval, and determine it as the third indicator based on the real-time number. Based on the relationship between the first indicator, the second indicator and the third indicator, determine the single-sided heat accumulation evaluation value. Based on the relationship between the single-sided heat accumulation evaluation value and the preset heat accumulation evaluation value, determine whether to automatically start the reverse compensation etching: when the single-sided 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-sided heat accumulation evaluation value is higher than the preset heat accumulation evaluation value, it is determined to automatically start the reverse compensation etching.

[0070] It is understandable that the trigger timing of the dual laser heads is adjusted by pulse phase difference feedback to ensure that the time interval of the front and back laser action is controllable. During laser processing, heat conduction and heat diffusion have a certain time delay. If the laser pulses on both sides are not accurately synchronized, it may cause excessive heat accumulation on one side, thereby destroying the thermal stress balance. Therefore, by adjusting the trigger timing through pulse phase difference feedback, the heat-affected zone of the double-sided laser action point is heated and cooled synchronously, thereby optimizing the overall thermal stress distribution and improving the etching uniformity and crystal stability. In order to further optimize the dynamic balance of double-sided laser etching, this method dynamically matches the front and back energy ratio based on the symmetry analysis of the thermal stress field. In the actual processing process, due to the differences in material thickness, thermal conduction characteristics and local stress state, the demand for laser energy on the front and back sides is not completely symmetrical. Therefore, if a fixed energy ratio is used, it may not be able to meet the stress balance requirements of all processing areas. By real-time monitoring of the thermal stress field distribution and combining finite element analysis or experimental feedback data, the front and back laser energy ratio can be dynamically adjusted to match the morphology of the heat-affected zones on both sides, thereby reducing local residual stress and improving etching accuracy and processing quality. When it is detected that the single-sided heat accumulation exceeds the preset range, the method determines whether to automatically start reverse compensation etching based on multiple indicators. First, by obtaining the influence ratio between the depth of the single-sided heat-affected zone and the thickness of the wafer (the first indicator), the diffusion of heat inside the material is 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 equilibrium interval (the third indicator) is obtained to evaluate the abnormal degree of stress state during etching. 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, the 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 an acceptable range and no additional intervention is required; but if the single-sided heat accumulation evaluation value exceeds the preset threshold, the system will automatically start reverse compensation etching, that is, add additional etching energy 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 reduce defects such as warping and cracks caused by unilateral heat accumulation, improves etching accuracy, and ensures the structural stability of the quartz crystal and the reliability of the final device.

[0071] It can be seen that in the process of laser double-sided etching, synchronously controlling the energy input of the laser on the front and back sides so that the double-sided thermal stress field forms a dynamic balance can effectively reduce the problem of stress gradient imbalance caused by unilateral heat accumulation. Traditional single-sided etching is prone to cause violent fluctuations in the local temperature field, resulting in large residual stress inside the crystal, thereby affecting the processing accuracy and material stability. However, this method achieves a dynamic balance of thermal stress by precisely controlling the trigger timing and energy matching of the front and back lasers, 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 trigger timing of the dual laser heads through pulse phase difference feedback, this method can accurately control the timing of the laser pulses on the front and back sides, so that the heat input is highly synchronized. This method 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 ratio of the front and back sides to further optimize the thermal field distribution. Due to the differences in the thermal conductivity characteristics of quartz crystals in different regions, a single fixed energy ratio may not meet the stress balance requirements of all regions. By analyzing the symmetry of the thermal stress field in real time and dynamically adjusting the laser energy input on the front and back sides according to the heat accumulation during the etching process, the local stress concentration phenomenon 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 heat accumulation on one side exceeds the preset range, this method can decide whether to automatically start the reverse compensation etching based on multiple evaluation indicators to ensure the continuous balance of heat input during the processing. By monitoring the depth of the heat-affected zone on one side, the temperature field distribution characteristics and stress fluctuations, the system can determine in real time whether additional compensation etching is needed. If the heat accumulation exceeds the safety threshold, the etching energy on the other side is automatically increased to restore the thermal field to balance. 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: acquiring the stress gradient distribution of the etching area in real time based on spectral analysis.

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

[0074] Specifically, when identifying the geometric characteristic parameters of the stress concentration area based on the real-time topological map, it includes: obtaining surface morphology data and determining the curvature radius and area ratio 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 lines, and the area ratio is based on the statistical quantification of the pixel density of the high stress area. The spatial distribution law of the lattice distortion vector is obtained, the anisotropic components of the lattice distortion are decomposed based on the Fourier transform algorithm, and the mapping relationship between the activation state of the dislocation slip system and the residual stress release path is established. 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 based on 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.

[0075] It is understandable that by collecting the mapping relationship between the Raman frequency shift and the stress value, the stress information can be accurately extracted from the spectral data of the etching area. Raman spectroscopy analysis technology can reflect the changes in the internal stress of the material by detecting the frequency shift changes of light. Therefore, by establishing the mapping relationship between the Raman frequency 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 topological map of the three-dimensional stress field, so that the stress distribution in the etching area can be visualized, providing accurate data support for subsequent processing adjustments. Using the real-time topological map, this method can identify the geometric characteristic parameters of the stress concentration area. During the etching process, due to the conduction of heat and the unevenness of material removal, stress may be concentrated in certain areas to form stress concentration areas. By analyzing the three-dimensional distribution of the stress field in real time, these stress concentration areas can be quickly located and their geometric features, such as the radius of curvature and area ratio, can be identified. The radius of curvature is calculated by the distribution characteristics of the curvature extreme points of the surface contour, which can reflect the shape characteristics of the stress concentration area; while the area ratio is quantified by counting the pixel density of the high stress area, which can evaluate the area size of the stress concentration area, thereby providing a basis for the subsequent adjustment of etching parameters. In addition to geometric characteristics, the spatial distribution law of the lattice distortion vector also plays an important role in analyzing the stress concentration area. By decomposing the anisotropic components of the lattice distortion through the Fourier transform algorithm, the strain information inside the crystal can be obtained, and the mapping relationship between the activation state of the dislocation slip system and the residual stress release path can be further established. This analysis method can reveal the dislocation movement and stress release mechanism in the crystal, and provide 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 morphological characteristics combined with the contact mechanics model can help construct a three-dimensional defect equivalent model, quantitatively analyze the depth and nature of the defect, and further understand and predict the defects that may occur during the etching process.

[0076] It can be seen that the geometric characteristic parameters of the stress concentration zone can be comprehensively evaluated by the radius of curvature, area ratio, activation state of the dislocation slip system, and equivalent mechanical depth of the defect. These parameters can comprehensively describe the morphological characteristics and mechanical state of the stress concentration area, and provide an important basis for stress regulation and optimization in the subsequent etching process. Through this series of analysis methods, the stress gradient distribution in the etching process can be accurately grasped, thereby effectively adjusting the laser processing parameters, reducing stress concentration, avoiding the occurrence of cracks or deformation, and ultimately improving the processing accuracy and reliability of quartz crystals.

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

[0078] Specifically, according to the deviation between the stress gradient and the target threshold, the laser processing parameter combination is dynamically adjusted, including: obtaining the stress gradient on both sides, and 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. 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.

[0079] Specifically, when controlling the effective action depth based on the change of defocus amount, it includes: establishing a nonlinear mapping model between defocus amount and molten pool depth; dynamically compensating the focus position according to the real-time etching rate; and adopting a gradual defocus strategy in the interface transition zone.

[0080] Specifically, when dynamically compensating the focal position according to the real-time etching rate, it includes: obtaining the plasma spectrum characteristics of the processing area, and calculating 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 focal offset, the model includes a material response coefficient and a thermal accumulation correction factor. When it is detected that the etching rate deviates from the set range, a focal position compensation instruction is generated according to the dynamic correlation model. The compensation instruction is executed based on the Z-axis motion platform to keep the laser focal plane and the material interface dynamically coincident.

[0081] Specifically, when the morphology-stress coupling optimization mode is started in the final processing stage, it includes: alternating morphology refinement scanning and stress release scanning. Inserting a micro-area remelting process in the area where the surface curvature suddenly changes. Applying prestress compensation according to the mesoscopic morphological characteristics, wherein: obtaining the microscopic surface morphology data of the target area, and calculating the 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 when planning the etching path 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 morphological structure is adjusted based on the path so that the stress is redistributed to the dynamic equilibrium range.

[0082] It is understandable that during the etching process, the stress gradient is monitored in real time and compared with the target threshold, and the high stress area is determined according to the relationship between the stress gradient and the material yield critical value. The laser power in the high stress area will be dynamically reduced to prevent further accumulation of stress in the area. This adjustment method helps to avoid stress concentration caused by local overheating, thereby reducing the risk of cracks in crystalline materials. At the same time, the scanning speed is also adjusted according to the ratio of the thermal 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 by changing the defocus amount, providing more precise depth control for the etching process. By establishing a nonlinear mapping model of the defocus amount and the molten pool depth, the focus position can be adjusted in real time to ensure that the effective action depth of the laser energy in the material is always maintained at the optimal state. This dynamic adjustment mechanism is particularly critical in the etching process because it can continuously compensate the focus position according to the change of the etching rate to prevent uneven etching depth caused by the focus position offset. In order to cope with the special requirements of the interface transition zone, a gradual defocus strategy is also proposed to further ensure efficient and uniform etching at different levels of the material. In the process of real-time compensation of the focus position, the acquisition of plasma spectral features becomes the key. By acquiring 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 rate of change of the etching rate and the focus offset. By establishing a dynamic correlation model, the focus offset can be accurately controlled, and compensation instructions can be generated when the etching rate deviates from the set range. Finally, the compensation instructions are executed based on the Z-axis motion platform to achieve dynamic coincidence between the laser focal plane and the material interface, ensuring the consistency of depth and precision during the etching process. In addition, in the final processing stage, this technology further optimizes the processing results of the quartz crystal by starting the morphology-stress coupling optimization mode. In this mode, by alternately performing morphology refinement scanning and stress release scanning, not only can the surface morphology be finely repaired, but also the stress concentration caused by etching can be effectively alleviated. In the area 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 quartz crystals, thereby improving their structural stability. Finally, by applying prestress compensation according to the mesoscopic morphological features, the technology further enhances the fine control of the etching process. By obtaining the microscopic surface morphology data of the target area and calculating the stress distribution based on the photoelastic effect, the stress changes inside the material can be accurately grasped. Using the lattice orientation-dependent anisotropic etching model, the local etching energy input can be adjusted to optimize the residual stress field.In addition, the combination of ultrashort pulse laser induced oscillation and multi-level energy gradient etching strategy can effectively generate a micro-oscillation field, promote the homogenization of internal stress, and form a gentle stress distribution gradient. Finally, the compensation etching path is calculated 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 gradient on both sides and comparing it with the material yield critical value, the high stress area can be accurately determined, and the laser power can be adjusted according to the stress change, thereby effectively avoiding stress concentration caused by local heat accumulation. In addition, combined with the adjustment of the ratio of thermal diffusion rate to etching rate, the heat distribution during laser etching is ensured to be uniform, avoiding material deformation or damage caused by local overheating. Therefore, this scheme effectively reduces stress unevenness and heat accumulation during etching, thereby improving the stability and reliability of the processed quartz crystal. Secondly, by controlling the effective action depth through the change of defocus, the technical scheme further improves the processing accuracy. The dynamic compensation focus position can ensure the highly accurate docking of the laser focus and the material interface during etching, avoiding the depth inconsistency caused by focus offset. By adopting a gradual defocusing strategy in the interface transition zone, uniform processing of the transition zone is ensured, reducing possible damage or uneven treatment of the material surface. This control method can better adapt to the complex changes in different processing areas, especially for high-demand precision etching tasks, and its operability and effect are more obvious. In addition, during the dynamic adjustment process, the monitoring and compensation of the real-time etching rate further enhance the adaptability and stability of the technology. By acquiring the plasma spectrum characteristics of the processing area in real time and dynamically compensating the focus 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 dynamic correlation model between the etching rate change rate and the focus offset is established, which makes the compensation of the focus position more accurate, providing a guarantee for the high-precision processing of quartz crystals. Through the execution of the compensation instruction of the Z-axis motion platform, the dynamic coincidence of the laser focal plane and the material interface is further guaranteed, which effectively improves the processing accuracy and consistency. At the same time, when the morphology-stress coupling optimization mode is started in the final processing stage, the technical solution effectively avoids cracks or structural instability caused by stress concentration or irregular surface morphology by alternately executing the strategy of morphology refinement scanning and stress release scanning. In addition, inserting the micro-area remelting process can further repair the surface curvature mutation area and improve the overall quality of the quartz crystal surface. These operations make the surface of the final 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 morphological characteristics and calculating the stress distribution in combination with the photoelastic effect, the technical solution can optimize the residual stress field of the material in real time during the processing process. By adjusting the local etching energy input to optimize the stress distribution, and combining ultrashort pulse laser induced oscillation and multi-level energy gradient etching strategies, the local stress area is homogenized, thus avoiding the stress concentration problem existing in traditional laser etching methods. Through the equivalent mechanical compensation strategy, the compensation path can be accurately calculated, and by adjusting the morphology structure, the final stress is ensured to be within the dynamic equilibrium range, thereby optimizing the overall performance and reliability of the quartz crystal.

[0084] In the above embodiment, by generating a 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 produces significant stress gradients due to heat accumulation, resulting in crystal deformation and even microcrack expansion. However, this method optimizes the double-sided etching path so that the material removal amounts on the front and back sides compensate each other, thereby significantly reducing the stress imbalance during the processing process and improving the consistency and accuracy of the etching morphology. At the same time, this method adopts synchronous control of the front and back laser energy input, and achieves dynamic balance of the double-sided thermal stress field through pulse phase regulation and energy ratio matching. Compared with the problem of unilateral heat accumulation in traditional single-sided processing, this method can effectively suppress warping and crack expansion caused by excessive temperature gradient. In addition, the synchronous control strategy can also improve the stability of the etching process, make the heat affected range of the processing area controllable, thereby reducing the structural damage caused by thermal stress concentration and improving the overall processing quality of quartz crystals. In terms of stress monitoring, this method achieves accurate evaluation of residual stress in the etching area by acquiring real-time stress gradients based on spectral analysis. Compared with the traditional stress detection method that relies 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 stress changes in real time during the etching process and construct a stress gradient distribution topology map. Such a real-time feedback mechanism enables the system to detect stress anomalies at an early stage, so as to adjust the processing parameters in time, prevent the formation of microcracks or stress concentration areas, and improve the yield rate. 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, the laser power, scanning speed, focus position and other processing parameters are adaptively adjusted. Compared with the traditional method of fixed processing parameters, this dynamic adjustment strategy can accurately compensate according to the stress state of different regions, realize the coordinated optimization of material removal uniformity and stress distribution balance, further reduce processing stress, and improve etching accuracy. Finally, in the final processing stage, this method adopts the morphology-stress coupling optimization mode, alternately performs morphology refinement scanning and stress release scanning, and combines the micro-area remelting process to make the surface morphology more uniform, while further releasing residual stress and optimizing the integrity of the crystal structure. Compared with the traditional single-step processing followed by additional annealing or polishing correction, this solution can directly optimize the morphology and stress distribution during the processing process, greatly reduce the post-processing process, and improve processing efficiency and product consistency.

[0085] In another preferred embodiment based on the above embodiment, Figure 2 As shown, this embodiment provides a laser double-sided etching stress control system for a quartz crystal, comprising:

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

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

[0088] Dynamic optimization engine configured to perform coupled thermal-mechanical simulations and adaptive parameter matching.

[0089] A cross-scale processing actuator includes 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 crystal in the above-mentioned embodiments of the present invention have the same beneficial effects, which will not be described in detail.

[0091] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may 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 codes.

[0092] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0093] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection 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.

2. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: 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, it is determined whether to automatically start the reverse compensation etching.

3. The laser double-sided etching stress control method for quartz crystal according to claim 2, 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.

4. 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.

5. The laser double-sided etching stress control method for quartz crystal according to claim 4, 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.

6. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: 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.

7. The laser double-sided etching stress control method for quartz crystal according to claim 6, characterized in that: When controlling the effective depth of action based on the change in defocus, it includes: A nonlinear mapping model between defocus amount and molten pool depth is established; Dynamically compensate the focus position according to the real-time etching rate; A gradual defocusing strategy is adopted in the interface transition zone.

8. The laser double-sided etching stress control method for quartz crystal according to claim 7, 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.

9. The laser double-sided etching stress control method for quartz crystal according to claim 1, characterized in that: When the topography-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.

10. 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 9, 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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