Vehicle gauge-level SMD (Surface Mounted Device) crystal and processing method thereof

Abstract

The invention belongs to the technical field of chips, and discloses a vehicle gauge-level SMD chip crystal and a processing method thereof, and the method comprises the steps: forming a gradient doped region on the surface layer of a quartz wafer through an ion implantation technology, and carrying out the recognition of the surface defects of the wafer and the etching of an anchor point groove based on a visual detection system; the etched doped quartz wafer is subjected to micro-electro-mechanical processing, a double-cantilever supporting structure is formed, a three-dimensional electromagnetic shielding layer is constructed on the surface of the wafer subjected to cantilever processing, a ceramic substrate and a metal conducting layer are alternately deposited through an additive manufacturing process, a polyimide-silicon dioxide colloid material is provided, and the three-dimensional electromagnetic shielding layer is formed; gradient distribution of an adhesive layer is realized through a micro-droplet jetting technology, a polyimide-silicon dioxide composite stress buffer layer is coated on a ceramic substrate, alignment and patch packaging are carried out on a processed crystal and a substrate, and through material modification and process collaborative optimization, the method is suitable for application in a high-temperature environment; the reliability problem in the extreme environment of the vehicle gauge is solved, and meanwhile the yield is improved.

Description

Technical Field

[0001] The present invention relates to the field of chip technology, and particularly to an automotive-grade SMD surface-mount crystal and a processing method thereof. Background Art

[0002] With the development of automotive electronics towards intelligence and networking, automotive-grade SMD surface-mount crystals, as the core components of clock signal sources, are widely used in autonomous driving domain controllers, in-vehicle communication modules, and sensor fusion systems. In scenarios of autonomous driving above level L3, the nanosecond-level clock synchronization accuracy of multiple sensors (lidar, millimeter-wave radar, camera) is directly related to the reliability of the decision-making system. However, the in-vehicle environment poses stringent requirements on components: it is necessary to maintain frequency stability (temperature drift < ±5 ppm) within a wide temperature range of -40°C to 125°C and withstand mechanical vibrations above 20G. Traditional consumer-grade or industrial-grade crystals are difficult to meet such requirements.

[0003] Existing automotive-grade SMD crystals mostly use standard AT-cut quartz wafers with epoxy resin encapsulation. Their processing method forms a wafer structure through photolithography and chemical etching, and then fixes it on a ceramic substrate with metal pads. However, such a solution has significant defects: the single material composition leads to insufficient suppression of temperature drift (±10~20 ppm), and the rigid encapsulation structure is prone to causing microcracks in the wafer under vibration stress, resulting in frequency jumps. For example, in an autonomous driving domain controller, the superposition of temperature drift of the crystal and the structural deformation caused by vibration under high-temperature conditions may lead to a clock synchronization error of multiple sensors exceeding 50 ns, and further cause target recognition misalignment or even decision-making failure. This limitation restricts its application in the field of high-precision in-vehicle chips.

[0004] In view of this, it is necessary to improve the SMD crystal technology in the prior art to solve the technical problem of its insufficient temperature resistance in the in-vehicle field. Summary of the Invention

[0005] The purpose of the present invention is to provide an automotive-grade SMD surface-mount crystal and a processing method thereof to solve the above technical problems.

[0006] To achieve this purpose, the present invention adopts the following technical solutions: A processing method for an automotive-grade SMD surface-mount crystal, comprising: forming a gradient doping region on the surface layer of the quartz wafer through an ion implantation process, identifying surface defects of the wafer based on a vision detection system, and etching anchor grooves based on the identification results; performing microelectromechanical processing on the etched doped quartz wafer to form a double-cantilever support structure, wherein cantilever beams are generated through a deep reactive ion etching process, and the mechanical properties of the cantilever support structure are optimized by combining dynamic stress compensation technology; Construct a three-dimensional electromagnetic shielding layer on the surface of the wafer after cantilever processing, where a ceramic substrate and a metal conductive layer are alternately deposited through an additive manufacturing process, and the morphology of the three-dimensional electromagnetic shielding layer is calibrated in real time based on a vision detection system; Provide a polyimide-silica colloidal material, realize a gradient distribution of the glue layer through a micro-droplet jetting technique, and apply a vibration spectrum simulation for pre-curing treatment to coat a composite stress buffer layer of polyimide-silica on the ceramic substrate; Align and patch-pack the processed crystal with the substrate, and perform dynamic calibration and fine-tuning on the cantilever structure based on the measurement of the resonant frequency.

[0007] Optionally, a gradient doping region is formed on the surface layer of the quartz wafer through an ion implantation process, and surface defects of the wafer are identified based on a vision detection system, and anchor grooves are etched based on the identification results, specifically including: Provide a quartz wafer and perform surface pretreatment, remove organic pollutants on the wafer surface through a plasma cleaning process, and coat a photoresist layer on the wafer surface, and form an ion implantation mask pattern through ultraviolet exposure; Adopt an ion beam assisted deposition process to form a gradient doping region on the surface layer of the quartz wafer. By controlling the ion beam energy and injection angle, lithium niobate nanoparticles are injected into the wafer surface layer at a gradient concentration, the injection depth is 50 μm, and the doping concentration decays exponentially from the surface layer to the interior; Identify surface defects of the doped quartz wafer based on a multi-spectral imaging system. Co-scan the wafer surface with visible light and infrared light, and combine an image recognition algorithm to locate and classify the defect areas to generate a defect distribution map; Plan the etching path of the anchor grooves according to the defect distribution map, avoid the defect areas through a path optimization algorithm, and mark the etching positions of the anchor grooves on the wafer surface; Adopt a reactive ion etching process to form anchor grooves on the quartz wafer surface. By controlling the etching gas flow rate and radio frequency power, anchor grooves are etched on the wafer surface; Clean and anneal the etched quartz wafer. Remove the etching residues through ultrasonic cleaning, and perform high-temperature annealing in a nitrogen environment to obtain the etched doped quartz wafer.

[0008] Optionally, perform microelectromechanical processing on the etched doped quartz wafer to form a double-cantilever support structure. Generate a cantilever beam through a deep reactive ion etching process, and optimize the mechanical properties of the cantilever support structure in combination with a dynamic stress compensation technique, specifically including: Provide the etched doped quartz wafer and perform surface cleaning. Remove the residual photoresist and etching by-products on the wafer surface through an ultrasonic cleaning process; Lithographic patterning is carried out on the wafer surface, and a mask pattern of a double cantilever beam is formed on the wafer surface by a deep ultraviolet lithography machine; A deep reactive ion etching process is used to generate the cantilever beam structure. By controlling the etching gas flow rate and radio frequency power, a double cantilever beam with a width of 10 μm and a thickness of 5 μm is etched on the wafer surface. During the etching process, the wafer temperature is monitored by an infrared thermal imager; Based on a laser vibrometer, the mechanical properties of the cantilever beam are measured. By applying a swept-frequency signal to excite the vibration of the cantilever beam, the natural frequency and vibration mode data of the cantilever beam are collected.

[0009] Optionally, after the mechanical properties of the cantilever beam are measured based on a laser vibrometer, by applying a swept-frequency signal to excite the vibration of the cantilever beam, and the natural frequency and vibration mode data of the cantilever beam are collected, it further includes: Combined with finite element analysis software, the stress distribution of the cantilever beam is simulated and optimized. Among them, a stress nephogram of the cantilever beam is generated according to the vibration measurement data, the stress concentration area is identified, and a local trimming scheme is generated through an AI algorithm; According to the simulation and optimization results, the femtosecond laser micromachining technology is used to locally trim the end mass of the cantilever beam, so that the natural frequency of the cantilever beam is stabilized at 25 kHz ± 5%, and the stress distribution is uniformized; The surface passivation treatment is carried out on the optimized cantilever beam structure. A silicon nitride protective layer with a thickness of 50 nm is formed on the surface of the cantilever beam by atomic layer deposition technology.

[0010] Optionally, a three-dimensional electromagnetic shielding layer is constructed on the wafer surface where the cantilever processing is completed. Among them, a ceramic substrate and a metal conductive layer are alternately deposited by an additive manufacturing process, and the morphology of the three-dimensional electromagnetic shielding layer is calibrated in real time based on a vision detection system. Specifically, it includes: A wafer on which the cantilever processing is completed is provided and surface pretreatment is carried out. Among them, the residual organic pollutants on the wafer surface are removed by a plasma cleaning process; The laser-induced metal deposition process is used to form a ceramic matrix layer with a thickness of 20 μm by pulsed laser selectively ablating ceramic slurry to construct a ceramic matrix layer on the wafer surface, A metal conductive layer is deposited on the surface of the ceramic matrix layer by aerosol jet printing technology. Among them, copper nanoparticles are used as the conductive material, and a continuous conductive path with a thickness of 5 μm is formed by controlling the jet pressure and substrate temperature; The morphology of the metal conductive layer is calibrated in real time. The surface of the conductive layer is scanned by a vision detection system. If holes or short-circuit defects are detected, local laser repair is triggered.

[0011] Optionally, the morphology of the metal conductive layer is calibrated in real time. The surface of the conductive layer is scanned by a vision detection system. If holes or short - circuit defects are detected, local laser repair is triggered. After that, it also includes: Deposit the ceramic substrate and the metal conductive layer again, forming a three - dimensional stacked structure with a total thickness of 50 μm to construct a three - dimensional electromagnetic shielding layer. The interface between each layer of ceramic and metal is enhanced in bonding strength through laser annealing treatment; Perform surface planarization treatment on the three - dimensional electromagnetic shielding layer, and verify the electromagnetic shielding effectiveness of the shielding layer based on the vision detection system. Measure the conductivity path continuity and shielding effectiveness of the shielding layer through a scanning electron microscope and an impedance analyzer. If not up to standard, trigger local additive repair.

[0012] Optionally, provide the polyimide - silica colloidal material, realize the gradient distribution of the glue layer through micro - droplet jetting technology, and apply vibration spectrum simulation for pre - curing treatment to coat a composite stress buffer layer of polyimide - silica on the ceramic substrate. Specifically, it includes: Mix the polyimide prepolymer and silica nanoparticles in a mass ratio of 3:1, form a uniform colloid through high - speed stirring, and filter out air bubbles to obtain the polyimide - silica colloidal material; Spray the colloidal material onto the substrate surface in an array of micro - droplets through micro - droplet jetting technology. The jetting pressure is 50 - 200 kPa, the substrate temperature is 25 - 80 °C, the glue layer thickness is 20 μm, and the gradient distribution is from the wafer side to the substrate side to coat the colloidal material on the ceramic substrate; Based on a high - speed camera, monitor the morphology of the glue layer in real time. By capturing the spreading morphology of the micro - droplets, dynamically adjust the jetting parameters in combination with the hydrodynamic model; Apply vibration spectrum simulation for pre - curing treatment to the coated glue layer. Among them, apply 20 - 2000 Hz random vibration through a piezoelectric shaker, and at the same time perform UV pre - curing to preliminarily cross - link the glue layer under stress; Perform thermal curing treatment on the pre - cured glue layer. Among them, perform step - wise heating in a nitrogen environment. The heating stages are 80 °C - 150 °C - 200 °C, 1 hour for each stage, to completely cure the glue layer and form a polyimide - silica composite stress buffer layer.

[0013] Optionally, align and patch - package the processed crystal with the substrate, and perform dynamic calibration and fine - tuning on the cantilever structure based on the measurement of the resonant frequency. Specifically, it includes: Prepare the alignment of the processed crystal with the ceramic substrate. Fix the crystal through a vacuum suction nozzle, and coat a layer of temporary adhesive with a thickness of 5 μm on the substrate to assist in the position fine - tuning during the alignment process; Alignment is performed using a force feedback fitting system. The contact pressure between the crystal and the substrate is monitored in real time by a micro-force sensor. If the pressure exceeds the limit, the piezoelectric ceramic micro-displacement platform is triggered for position compensation; Hermetic packaging is completed in a vacuum environment. After the crystal and the substrate are fitted, nitrogen is filled, and the cavity is hermetically packaged by a laser welding process.

[0014] Optionally, after the hermetic packaging is completed in a vacuum environment, where the crystal and the substrate are fitted, nitrogen is filled, and the cavity is hermetically packaged by a laser welding process, the following steps are further included: Dynamic calibration of the cantilever structure is performed based on a resonance frequency measuring device. Among them, a swept-frequency signal is applied by a piezoelectric exciter, the response of the cantilever is measured by a laser vibrometer, and a frequency-amplitude curve is generated. If the measured frequency deviates from the target value, a laser micromachining technique is triggered to perform local trimming on the mass block at the end of the cantilever; The surface of the packaged crystal is cleaned and marked. Surface residues are removed by plasma cleaning, and the product number and batch information are laser-engraved on the surface of the package.

[0015] The present invention also provides an automotive-grade SMD chip crystal, which is prepared by using the processing method of the automotive-grade SMD chip crystal as described above. The automotive-grade SMD chip crystal specifically includes: A gradient-doped quartz wafer, and a gradient-doped region is formed on the surface layer of the wafer by an ion implantation process; A double-cantilever support structure, and a double-cantilever beam structure is formed on the wafer surface by a deep reactive ion etching process; A three-dimensional electromagnetic shielding layer, where a ceramic matrix and a metal conductive layer are alternately deposited on the surface of the cantilever structure by an additive manufacturing process to form a three-dimensional stacked structure with a total thickness of 50 μm; A composite stress buffer layer, which is formed by coating a polyimide-silica gel material on a ceramic substrate by a micro-droplet injection technique; A hermetic packaging layer, and the crystal and the substrate are hermetically packaged by vacuum fitting and laser welding.

[0016] Compared with the prior art, the present invention has the following beneficial effects: By means of an ion implantation process, a gradient doping region is formed on the surface layer of a quartz wafer. Based on a vision detection system, surface defects of the wafer are identified and anchor grooves are located for etching, thereby improving the temperature drift stability of the wafer. For the doped wafer after etching, a deep reactive ion etching process is used to fabricate a double-cantilever support structure, and the mechanical properties of the cantilever are optimized by combining dynamic stress compensation technology, effectively avoiding wafer fracture. On the surface of the cantilever structure, a ceramic matrix and a metal conductive layer are alternately deposited through an additive manufacturing process to form a three-dimensional electromagnetic shielding layer, and the morphology of the shielding layer is calibrated in real time by using a vision detection system to reduce the disturbance of electromagnetic interference to the clock signal. On a ceramic substrate, a polyimide-silica composite stress buffer layer is coated by a micro-droplet spraying technique, and pre-curing treatment is achieved by applying a vibration spectrum simulation. Finally, the processed crystal and the substrate are subjected to sub-micron alignment packaging, and the cantilever structure is dynamically calibrated based on resonance frequency measurement. Overall, this method, through the collaborative optimization of material modification and process, is suitable for applications in high-temperature environments, solves the reliability problem in the extreme environment of vehicle specifications, and improves the yield at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that the technical content disclosed by the present invention can cover.

[0019] Figure 1 It is one of the flow diagrams of the processing method of the vehicle-grade SMD patch crystal in Embodiment 1; Figure 2 It is another flow diagram of the processing method of the vehicle-grade SMD patch crystal in Embodiment 1; Figure 3 It is the main body diagram of the vehicle-grade SMD patch crystal in Embodiment 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the object, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be intermediate components present.

[0022] The following further illustrates the technical solutions of the present invention with reference to the accompanying drawings and through specific embodiments.

[0023] Embodiment 1: Combined with Figure 1 and Figure 2 As shown, the embodiments of the present invention provide a processing method for automotive-grade SMD chip crystals, including: S1, forming a gradient doping region on the surface layer of the quartz wafer through an ion implantation process, identifying surface defects of the wafer based on a vision detection system, and etching anchor grooves based on the identification results; preparing a highly uniform doped quartz wafer and completing pre-forming of the wafer-level structure. The temperature drift stability of the wafer is improved through the gradient doping process (temperature drift ≤ ±3 ppm), and the yield of wafer cutting is improved by combining vision defect recognition.

[0024] S2, performing microelectromechanical processing on the etched doped quartz wafer to form a double-cantilever support structure, wherein the cantilever beams are generated through a deep reactive ion etching process, and the mechanical properties of the cantilever support structure are optimized by combining dynamic stress compensation technology; an anti-vibration cantilever beam structure is etched on the wafer, and the mechanical stress distribution is optimized. The double-cantilever structure and the dynamic stress compensation technology enable the anti-vibration ability to reach 30 G (traditional process < 10 G), effectively avoiding wafer fracture.

[0025] S3. Construct a three-dimensional electromagnetic shielding layer on the surface of the wafer after cantilever processing. Among them, the ceramic substrate and the metal conductive layer are alternately deposited through the additive manufacturing process, and the morphology of the three-dimensional electromagnetic shielding layer is calibrated in real time based on the vision detection system; construct a metal-ceramic composite electromagnetic shielding layer on the wafer surface. The 3D shielding layer fabricated by additive manufacturing ensures the integrity of the conductive path through vision calibration, reducing the disturbance of electromagnetic interference to the clock signal.

[0026] S4. Provide a polyimide-silica colloidal material, realize the gradient distribution of the glue layer through the micro-droplet injection technology, and apply vibration spectrum simulation for pre-curing treatment to coat a composite stress buffer layer of polyimide-silica on the ceramic substrate; coat an adaptive buffer layer between the wafer and the ceramic substrate to absorb vibration energy.

[0027] S5. Align and patch-pack the processed crystal with the substrate, and perform dynamic calibration and fine-tuning on the cantilever structure based on the resonant frequency measurement. Complete the high-precision packaging of the wafer and the substrate, and calibrate the mechanical properties of the cantilever. The hermetic packaging and resonant calibration technology will reduce the error of frequency stability and meet the high-precision synchronization requirements of automotive-grade applications.

[0028] The working principle of the present invention is as follows: a gradient doping region is formed on the surface layer of the quartz wafer through the ion implantation process. Based on the vision detection system, the surface defects of the wafer are identified and the anchor point grooves are located for etching to improve the temperature drift stability of the wafer; the double-cantilever support structure is processed on the etched doped wafer by the deep reactive ion etching process, and the mechanical properties of the cantilever are optimized by combining the dynamic stress compensation technology to effectively avoid wafer fracture; on the surface of the cantilever structure, the ceramic matrix and the metal conductive layer are alternately deposited through the additive manufacturing process to form a three-dimensional electromagnetic shielding layer, and the morphology of the shielding layer is calibrated in real time by using the vision detection system to reduce the disturbance of electromagnetic interference to the clock signal; a polyimide-silica composite stress buffer layer is coated on the ceramic substrate through the micro-droplet injection technology, and vibration spectrum simulation is applied to achieve pre-curing treatment; finally, the processed crystal and the substrate are sub-micron aligned and packaged, and the cantilever structure is dynamically calibrated based on the resonant frequency measurement; overall, this method adapts to applications in high-temperature environments through material modification and process collaborative optimization, solves the reliability problem in the extreme automotive-grade environment, and improves the yield at the same time.

[0029] In this embodiment, specifically, step S1 specifically includes: S11. Provide a quartz wafer and perform surface pretreatment. Remove the organic pollutants on the wafer surface through the plasma cleaning process, and coat a photoresist layer on the wafer surface to form an ion implantation mask pattern through ultraviolet exposure; Through the plasma cleaning process (the gas is Ar / O 2A mixed gas (with a power of 300 W) is used to remove organic contaminants (such as grease and dust) on the surface of the quartz wafer, ensuring the adhesion and cleanliness of subsequent processes. Subsequently, a photoresist layer is spin-coated on the wafer surface, and a mask pattern is transferred to the photoresist layer using an ultraviolet exposure machine to form a mask pattern (line width accuracy ±0.5 μm) required for ion implantation.

[0030] S12. An ion beam assisted deposition process is used to form a gradient doping region on the surface layer of the quartz wafer. By controlling the ion beam energy (10 - 50 keV) and the implantation angle (0° - 45°), lithium niobate nanoparticles are implanted into the wafer surface layer at a gradient concentration. The implantation depth is 50 μm, and the doping concentration exponentially decays from the surface layer to the interior. Using the ion beam assisted deposition (IBAD) process, by adjusting the ion beam energy (10 - 50 keV) and the incident angle (0° - 45°), lithium niobate nanoparticles are implanted into the surface layer of the quartz wafer (depth 50 μm). The doping concentration exponentially decays from the surface layer to the interior (surface layer concentration 1×10 20 atoms / cm 3 , and it drops to 1×10 18 atoms / cm 3 ) inside. This gradient design reduces the temperature drift to ±3 ppm by suppressing the difference in the lattice thermal expansion coefficient.

[0031] Among them, the regulation of ion beam energy / angle realizes the gradient distribution of doping concentration; the doping of lithium niobate nanoparticles enhances the rigidity of the quartz lattice and improves the temperature stability.

[0032] S13. Based on a multi-spectral imaging system, surface defect identification of the doped quartz wafer is carried out. By scanning the wafer surface synergistically with visible light and infrared light, and combining an image recognition algorithm, the defect areas (cracks, impurities, doping non-uniformity) are located and classified to generate a defect distribution map. The doped wafer is scanned in two bands using a multi-spectral imaging system (visible light wavelength 400 - 700 nm, infrared light wavelength 3 - 5 μm). Combining the CNN image recognition algorithm, surface defects (cracks, impurities, doping non-uniformity) are identified and classified (accuracy > 99%) to generate a defect distribution heat map (resolution 1 μm / pixel). The defect location accuracy reaches ±2 μm, providing data support for subsequent etching path planning.

[0033] Among them, multi-spectral synergistic scanning enhances the sensitivity of defect detection; the CNN image recognition algorithm automates defect classification and quantification, avoiding manual misjudgment.

[0034] S14. Plan the etching path of the anchor grooves according to the defect distribution map, avoid the defect areas through the path optimization algorithm, and mark the etching positions of the anchor grooves on the wafer surface. Among them, the A* algorithm is selected for obstacle avoidance optimization to maximize the utilization of the effective area of the wafer and improve the yield.

[0035] Based on the defect distribution map, use the improved A* path planning algorithm (heuristic function weighted obstacle avoidance factor) to dynamically generate the etching path of the anchor grooves, avoiding all defect areas (safety distance ≥ 5 μm). Mark the etching positions on the wafer surface through a laser marking machine (marking accuracy ±1 μm) to ensure the positioning accuracy of the subsequent etching process.

[0036] S15. Use the reactive ion etching process to form anchor grooves on the surface of the quartz wafer. By controlling the flow rate of the etching gas (SF 6 / O 2 mixed gas) and the RF power, etch anchor grooves with a depth of 10 μm and a width of 20 μm on the wafer surface. During the etching process, adjust the process parameters by real-time monitoring of the etching rate to ensure the consistency of the groove morphology. Use the reactive ion etching (RIE) process (the gas is SF 6 / O 2 mixed gas, flow rate 50 sccm, RF power 200 W) to etch anchor grooves (depth 10 μm, width 20 μm, sidewall perpendicularity > 85°) on the surface of the quartz wafer. Monitor the etching by-products (such as SiF 4 ) through a real-time mass spectrometer and dynamically adjust the gas ratio to ensure the stability of the etching rate.

[0037] S16. Clean and anneal the etched quartz wafer. Remove the etching residues through ultrasonic cleaning and perform high-temperature annealing in a nitrogen environment to obtain the etched doped quartz wafer. The temperature of the high-temperature annealing is 800 °C and the time is 2 hours to repair the lattice damage generated during the etching process and improve the mechanical strength of the wafer.

[0038] In this embodiment, specifically, step S2 specifically includes: S21. Provide the etched doped quartz wafer and perform surface cleaning. Remove the residual photoresist and etching by-products on the wafer surface through the ultrasonic cleaning process to improve the accuracy of the subsequent lithography process.

[0039] Remove the residual photoresist and etching by-products (such as fluoride particles) on the surface of the etched wafer through the ultrasonic cleaning process (frequency 40 kHz, power 150 W). The cleaning solution is a mixed solution of deionized water and isopropyl alcohol (volume ratio 3:1) to ensure the surface cleanliness (pollutant residue < 0.1 μg / cm 2 ). Subsequently, use the nitrogen drying process to avoid the influence of water mark residues on the subsequent lithography accuracy.

[0040] Among them, the ultrasonic cavitation effect efficiently removes sub-micron residues; non-polar solvent cleaning avoids chemical corrosion of the surface of the quartz wafer.

[0041] S22, perform photolithographic patterning on the wafer surface, and form a mask pattern of a double cantilever beam on the wafer surface through a deep ultraviolet lithography machine. During the lithography process, the alignment accuracy is monitored in real time to ensure the position accuracy of the cantilever beam; Use a deep ultraviolet lithography machine (wavelength 248nm, NA = 0.65) to form a mask pattern of a double cantilever beam (line width 10μm, pitch 5μm) on the wafer surface, and ensure the alignment of the pattern with the wafer reference mark through a high-precision alignment system. During the lithography process, the alignment deviation is monitored by a real-time CCD imaging system. If the deviation exceeds the threshold (>0.2μm), the piezoelectric platform is triggered to finely adjust the wafer position.

[0042] S23, use a deep reactive ion etching process to generate a cantilever beam structure. By controlling the flow rate of the etching gas (SF 6 / C 4 F 8 mixed gas) and the radio frequency power, etch a double cantilever beam with a width of 10μm and a thickness of 5μm on the wafer surface. During the etching process, monitor the wafer temperature through an infrared thermal imager to prevent microcracks caused by thermal stress; Use the Bosch process (alternately introduce SF 6 etching gas and C 4 F 8 passivation gas) to etch a double cantilever beam structure (width 10μm, thickness 5μm, aspect ratio 5:1) under the conditions of a radio frequency power of 300W and a gas pressure of 10mTorr. During the etching process, monitor the wafer temperature in real time through an infrared thermal imager. If the local temperature exceeds 150°C, automatically reduce the radio frequency power or pause the etching to prevent microcracks caused by thermal stress.

[0043] S24, measure the mechanical properties of the cantilever beam based on a laser vibrometer. By applying a swept-frequency signal to excite the vibration of the cantilever beam, and collect the natural frequency and vibration mode data of the cantilever beam; Apply a swept-frequency signal (10 - 50kHz, step size 100Hz) through a piezoelectric exciter to excite the vibration of the cantilever beam, use a laser vibrometer to collect the vibration displacement and phase data of the cantilever beam, and generate curves of the natural frequency and vibration mode (first-order bending / torsion mode).

[0044] S25, combine finite element analysis software to simulate and optimize the stress distribution of the cantilever beam. Among them, generate a stress nephogram of the cantilever beam according to the vibration measurement data, identify the stress concentration area, and generate a local trimming scheme through an AI algorithm; Import the vibration measurement data into the finite element analysis (FEA) software, construct a three-dimensional model of the cantilever beam and calculate the stress distribution (mesh size 1μm), and identify the stress concentration areas (>50MPa). Analyze the historical data through a machine learning algorithm (random forest model) to generate a local trimming scheme (such as reducing the weight of the mass block or geometric fine-tuning), with the optimization objectives being stress uniformity and frequency stability.

[0045] S26. According to the simulation optimization results, use femtosecond laser micromachining technology to locally trim the mass block at the end of the cantilever beam, so that the natural frequency of the cantilever beam is stabilized at 25kHz ± 5%, and the stress distribution is homogenized; Use femtosecond laser micromachining technology to perform dynamic stress compensation on the cantilever beam. According to the simulation optimization results, locally trim the mass block at the end of the cantilever beam (remove <0.1μg of material), so that the natural frequency of the cantilever beam is stabilized at 25kHz ± 5%, and the stress distribution is homogenized (deviation <10%).

[0046] S27. Perform surface passivation treatment on the optimized cantilever beam structure, and form a silicon nitride protective layer with a thickness of 50nm on the surface of the cantilever beam through atomic layer deposition technology to improve the fatigue resistance of the cantilever beam.

[0047] Deposit silicon nitride (Si 3 N 4 ) protective layer on the surface of the cantilever beam through atomic layer deposition (ALD) process. The process temperature is 300°C, and the precursors are SiCl 4 and NH 3 . The silicon nitride layer can isolate environmental moisture and pollutants, and improve the fatigue resistance and corrosion resistance of the cantilever beam.

[0048] In this embodiment, specifically, step S3 specifically includes: S31. Provide the wafer after cantilever processing and perform surface pretreatment, where the residual organic pollutants on the wafer surface are removed through plasma cleaning process; preferably, a silicon dioxide transition layer with a thickness of 100nm can be coated on the wafer surface to enhance the adhesion between the shielding layer and the wafer; Remove the organic pollutants (such as photoresist residue, grease) on the wafer surface after cantilever processing through plasma cleaning process (Ar / O 2 mixed gas, power 200W, time 5min) to ensure the interface cleanliness between the shielding layer and the wafer.

[0049] S32. Adopt laser-induced metal deposition process, and form a ceramic matrix layer with a thickness of 20μm by pulse laser selectively ablating ceramic slurry to construct a ceramic matrix layer on the wafer surface; Adopt laser-induced metal deposition process, and ablate ceramic slurry (Al 2 O3 a nanoparticle dispersion liquid), to form a ceramic matrix layer (with a thickness of 20 μm and a density > 95% of the theoretical value) on the wafer surface. The ablation depth of the laser ablation area is monitored in real time by an imaging system to ensure the uniformity of the layer thickness.

[0050] S33, deposit a metal conductive layer on the surface of the ceramic matrix layer by aerosol jet printing technology, where copper nanoparticles (with a particle size of 20 nm) are used as the conductive material, and a continuous conductive path with a thickness of 5 μm is formed by controlling the jet pressure (50 - 200 kPa) and the substrate temperature; Using aerosol jet printing technology, copper nanoparticles (with a particle size of 20 nm and a solid content of 30%) are sprayed onto the surface of the ceramic matrix layer in the form of atomized droplets. By controlling the jet pressure (50 - 200 kPa) and the substrate temperature (80 °C), a continuous conductive layer (with a thickness of 5 μm and a resistivity < 2 μΩ·cm) is formed. The jet path is optimized by an AI algorithm to avoid short circuits caused by metal accumulation.

[0051] Among them, the low-temperature forming of nanoparticle aerosol avoids high-temperature damage to the ceramic layer; the dynamic path planning combines with a hydrodynamic model (Reynolds number Re = 50 - 200) to optimize the jet trajectory.

[0052] S34, perform real-time calibration on the morphology of the metal conductive layer. Scan the surface of the conductive layer through a vision detection system. If holes or short-circuit defects are detected, trigger local laser repair; Scan the surface of the metal conductive layer through a high-resolution CCD vision system (with an accuracy of 0.5 μm) to detect holes (with a diameter > 2 μm) or short-circuit areas (with a spacing < 5 μm). If defects are detected, trigger a pulsed laser to perform local repair on the defect area: supplement copper nanoparticles in the hole area and perform laser sintering, and ablate the excess metal in the short-circuit area.

[0053] S35, repeat the deposition of the ceramic substrate and the metal conductive layer again to form a three-dimensional stacked structure with a total thickness of 50 μm to construct a three-dimensional electromagnetic shielding layer, where the interface between each layer of ceramic and metal is enhanced in bonding strength by laser annealing treatment; Repeat steps S32 to S34, alternately deposit the ceramic matrix layer (with a total thickness of 30 μm) and the metal conductive layer (with a total thickness of 20 μm) to form a three-dimensional stacked shielding structure. The interface between each layer realizes ceramic-metal metallurgical bonding through laser annealing treatment, and the interface shear strength is increased to 50 MPa.

[0054] S36, perform surface planarization treatment on the three-dimensional electromagnetic shielding layer, and verify the electromagnetic shielding effectiveness of the shielding layer based on the vision detection system. Measure the continuity of the conductive path and the shielding effectiveness of the shielding layer through a scanning electron microscope and an impedance analyzer. If it does not meet the standard, trigger local additive repair; The surface roughness of the shielding layer is reduced to Ra < 10 nm by chemical mechanical polishing (CMP) process (polishing solution pH = 4, pressure 3 psi), and warping is eliminated. The continuity of the conductive path is observed by scanning electron microscope, and the shielding effectiveness (SE = 20log(E 0 / E 1 )) is measured by an impedance analyzer (frequency 1 MHz - 10 GHz). If SE < 60 dB, local additive repair (spraying copper particles + laser sintering) is triggered.

[0055] Among them, CMP global planarization eliminates the influence of surface undulations on subsequent processes; the shielding effectiveness test in the frequency domain verifies electromagnetic compatibility in multiple frequency bands.

[0056] Through the full - process control of ceramic - metal alternating deposition - visual calibration - interface strengthening - effectiveness verification, a three - dimensional electromagnetic shielding layer with high density (porosity < 1%) and strong bonding (peel strength > 15 N / cm) is constructed, and the shielding effectiveness > 60 dB (1 - 10 GHz frequency band), solving the electromagnetic interference problem of automotive - grade SMD crystals in the environment of high - voltage motors and vehicle - mounted radars.

[0057] In this embodiment, specifically, step S4 specifically includes: S41, mixing the polyimide prepolymer and silica nanoparticles in a mass ratio of 3:1, forming a homogeneous colloid by high - speed stirring, and filtering to remove air bubbles to obtain a polyimide - silica colloid material; Mix the polyimide prepolymer and silica nanoparticles (particle size 50 nm) in a mass ratio of 3:1, and achieve uniform dispersion through a high - speed mixer to form a colloid mixture (silica volume fraction 25%). Subsequently, a vacuum degassing device is used to remove air bubbles in the colloid to ensure the fluidity and molding stability of the colloid.

[0058] Among them, the dispersion of nanoparticles is achieved through the synergistic action of shear force and van der Waals force to prevent particle agglomeration; vacuum degassing eliminates the defects in the colloid layer caused by air bubbles.

[0059] S42, spraying the colloid material onto the surface of the substrate in the form of array micro - droplets through micro - droplet injection technology, with an injection pressure of 50 - 200 kPa, a substrate temperature of 25 - 80 °C, and a colloid layer thickness of 20 μm, with a gradient distribution from the wafer side to the substrate side, to coat the colloid material on the ceramic substrate; Using a piezoelectric micro - droplet injection system, spraying the colloid in the form of array micro - droplets (diameter 30 μm, spacing 40 μm) onto the surface of the ceramic substrate, and dynamically adjusting the injection pressure and substrate temperature through a gradient control algorithm, so that the colloid layer thickness gradually changes from 25 μm on the wafer side (2 GPa modulus region) to 15 μm on the substrate side (5 GPa modulus region), forming a continuous gradient distribution.

[0060] S43. Based on real-time monitoring of the adhesive layer morphology by a high-speed camera, the injection parameters are dynamically adjusted by capturing the spreading morphology of micro-droplets and combining with a hydrodynamic model; The spreading morphology (diameter, contact angle) of the micro-droplets after impacting the substrate is captured by a high-speed camera (frame rate 1000fps, resolution 5μm / pixel), and the spreading dynamics is calculated by combining with a hydrodynamic model (laminar flow model based on Reynolds number Re = 10 - 100), and the injection parameters (such as pressure increment ±10kPa, temperature adjustment ±5°C) are dynamically optimized to ensure the thickness uniformity and gradient continuity of the adhesive layer.

[0061] Among them, multi-physics field modeling couples the hydrodynamic and heat conduction equations to predict the behavior of micro-droplets; closed-loop feedback control iteratively optimizes the injection parameters driven by real-time data.

[0062] S44. Apply vibration spectrum simulation to the coated adhesive layer for pre-curing treatment, where 20 - 2000Hz random vibration is applied by a piezoelectric shaker, and at the same time UV pre-curing is carried out to preliminarily crosslink the adhesive layer under stress; 20 - 2000Hz random vibration is applied to the substrate coated with the adhesive layer by a piezoelectric shaker to simulate the vehicle vibration environment; at the same time, the surface of the adhesive layer is irradiated with a UV light source to cause the decomposition of the photoinitiator to generate active free radicals, so that the adhesive layer is preliminarily crosslinked under dynamic stress, and the fatigue resistance is increased by 3 times.

[0063] Among them, vibration-photocuring synergistically induces the directional arrangement of molecular chains under stress to enhance mechanical properties; UV penetration depth control realizes preferential curing of the surface layer through the light intensity gradient.

[0064] S45. Carry out thermal curing treatment on the pre-cured adhesive layer, where stepwise heating is carried out in a nitrogen environment, and the heating stages are 80°C - 150°C - 200°C, 1 hour for each stage, to completely cure the adhesive layer and form a polyimide-silica composite stress buffer layer, and the Young's modulus gradient ranges from 2GPa (wafer side) to 5GPa (substrate side); The pre-cured adhesive layer is placed in a heat treatment furnace with a nitrogen atmosphere (oxygen content < 10ppm) and cured by stepwise heating in three stages: 80°C (1 hour, removing residual solvents), 150°C (1 hour, promoting the imidization reaction of polyimide), 200°C (1 hour, complete crosslinking). Stepwise heating avoids cracking of the adhesive layer caused by thermal stress, and finally forms a polyimide-silica composite stress buffer layer.

[0065] Among them, stepwise temperature control matches the reaction kinetics of the material to inhibit interface delamination; nitrogen protection prevents performance deterioration caused by high-temperature oxidation.

[0066] Through the process chain of colloidal gradient coating - vibration pre-curing - inert thermal crosslinking, a polyimide-silica composite stress buffer layer with a Young's modulus gradient (2GPa → 5GPa) and a fatigue resistance life > 107 For the composite buffer layer in the next cycle, the vibration energy absorption rate is increased to 90% (60% for the traditional epoxy resin buffer layer), solving the problem of interface failure of automotive-grade SMD patch crystals under complex mechanical vibrations.

[0067] In this embodiment, specifically, step S5 specifically includes: S51, Prepare for alignment of the processed crystal and the ceramic substrate. Fix the crystal with a vacuum suction nozzle, and coat a layer of temporary adhesive with a thickness of 5 μm on the substrate to assist in fine-tuning the position during the alignment process; Fix the processed crystal with a vacuum suction nozzle (the adsorption force is adjustable from 0.1 - 1 N) to ensure no mechanical clamping damage; Spin-coat a temporary adhesive (acrylate-based photocurable adhesive) on the surface of the ceramic substrate, and use UV pre-curing to form a slightly sticky surface to assist in fine-tuning during the alignment process. Temporary adhesion: low-viscosity reversible bonding, facilitating subsequent peeling.

[0068] S52, Use a force feedback bonding system for alignment. Real-time monitor the contact pressure between the crystal and the substrate through a micro-force sensor. If the pressure exceeds the limit, trigger the piezoelectric ceramic micro-displacement platform for position compensation; Use a force feedback bonding system to real-time monitor the contact pressure between the crystal and the substrate. If the pressure exceeds the threshold (>0.5 N), trigger the six-axis piezoelectric ceramic micro-displacement platform for position compensation, and control the alignment accuracy within ±1 μm. After alignment, enhance the strength of the temporary adhesive through UV secondary curing (intensity 200 mW / cm 2 )

[0069] Among them, dynamic force feedback control prevents the cantilever structure from breaking due to overpressure; multi-degree-of-freedom piezoelectric compensation adapts to the complex curved surface bonding requirements.

[0070] S53, Complete hermetic packaging in a vacuum environment. After fitting the crystal and the substrate, fill it with nitrogen, and seal the package cavity through a laser welding process; Place the fitted component in a vacuum cavity, fill it with high-purity nitrogen to displace the residual gas, and then use pulsed fiber laser welding to seal the cover plate. The weld width is 100 μm, and the helium leak rate <5×10 -8 atm·cc / s, ensuring that the airtightness meets the MIL-STD-883 standard.

[0071] Laser deep penetration welding has a narrow heat-affected zone (<20 μm), avoiding thermal damage; Nitrogen inert protection: inhibits oxidation reactions in the package cavity.

[0072] S54. Dynamically calibrate the cantilever structure based on a resonance frequency measurement device, where a swept-frequency signal is applied through a piezoelectric exciter, the cantilever response is measured using a laser vibrometer, and a frequency-amplitude curve is generated. If the measured frequency deviates from the target value, trigger the laser micromachining technology to locally trim the mass at the end of the cantilever. Apply a linear swept-frequency signal through a piezoelectric exciter, measure the cantilever vibration response using a laser Doppler vibrometer, and generate a frequency-amplitude curve. If the measured natural frequency deviates from the target value (25 kHz ± 0.1%), use femtosecond laser to locally ablate the mass at the end of the cantilever (material removal amount < 0.1 μg), and reduce the frequency error through iterative trimming.

[0073] S55. Clean and mark the surface of the packaged crystal, remove surface residues through plasma cleaning, and laser engrave the product number and batch information on the surface of the package.

[0074] Use plasma cleaning to remove the organic residues on the surface of the package, and then engrave the QR code and batch information on the surface of the package through ultraviolet laser, meeting the traceability requirements of the AEC-Q200 standard.

[0075] Example 2: Combined with Figure 3 As shown, the present invention also provides an automotive-grade SMD chip crystal, which is prepared by using the processing method of the automotive-grade SMD chip crystal in Example 1. The automotive-grade SMD chip crystal specifically includes: Gradient-doped quartz wafer 10, and a gradient doping region is formed on the surface layer of the wafer through ion implantation technology.

[0076] Double-cantilever support structure 20, and a double-cantilever beam structure is formed on the wafer surface through deep reactive ion etching technology.

[0077] Three-dimensional electromagnetic shielding layer 30, and a ceramic matrix and a metal conductive layer are alternately deposited on the surface of the cantilever structure through additive manufacturing technology to form a three-dimensional stacked structure with a total thickness of 50 μm.

[0078] Composite stress buffer layer 40, which is formed by coating a polyimide-silica gel material on a ceramic substrate through microdroplet jetting technology; Hermetic packaging layer, and the crystal and the substrate are hermetically packaged through vacuum bonding and laser welding.

[0079] As described above, 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 foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for processing automotive-grade SMD chip crystals, characterized in that: include: A gradient doping region is formed on the surface of the quartz wafer through an ion implantation process, and surface defects of the wafer are identified based on a visual inspection system, and anchor grooves are etched based on the identification results; The etched doped quartz wafer is micro-electromechanically processed to form a dual cantilever support structure, wherein the cantilever beam is generated by deep reactive ion etching process, and the mechanical properties of the cantilever support structure are optimized by combining dynamic stress compensation technology; A three-dimensional electromagnetic shielding layer is constructed on the surface of the wafer after cantilever processing, wherein a ceramic substrate and a metal conductive layer are alternately deposited through an additive manufacturing process, and the morphology of the three-dimensional electromagnetic shielding layer is calibrated in real time based on a visual inspection system; Providing a polyimide-silicon dioxide colloidal material, achieving a gradient distribution of the glue layer by a microdroplet jetting technique, and applying a vibration spectrum simulation for pre-curing treatment, so as to coat a polyimide-silicon dioxide composite stress buffer layer on the ceramic substrate; The processed crystal is aligned with the substrate and packaged, and the cantilever structure is dynamically calibrated and fine-tuned based on the resonant frequency measurement.

2. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The method forms a gradient doping region on the surface of a quartz wafer by an ion implantation process, identifies surface defects of the wafer based on a visual inspection system, and etches the anchor groove based on the identification result, specifically including: Providing quartz wafers and performing surface pretreatment, removing organic pollutants on the wafer surface through a plasma cleaning process, coating a photoresist layer on the wafer surface, and forming an ion implantation mask pattern through ultraviolet exposure; An ion beam assisted deposition process is used to form a gradient doping area on the surface of a quartz wafer. By controlling the ion beam energy and the injection angle, lithium niobate nanoparticles are injected into the surface of the wafer at a gradient concentration. The injection depth is 50 μm, and the doping concentration is exponentially decayed from the surface to the inside. The surface defects of doped quartz wafers are identified based on a multispectral imaging system. The wafer surface is scanned collaboratively with visible light and infrared light, and the defective areas are located and classified in combination with an image recognition algorithm to generate a defect distribution map. Plan the etching path of the anchor groove according to the defect distribution map, avoid the defect area through the path optimization algorithm, and mark the etching position of the anchor groove on the wafer surface; Anchor grooves are formed on the surface of a quartz wafer using a reactive ion etching process. The anchor grooves are etched on the surface of the wafer by controlling the etching gas flow and the radio frequency power. The etched quartz wafer is cleaned and annealed, the etching residues are removed by ultrasonic cleaning, and high-temperature annealing is performed in a nitrogen environment to obtain the etched doped quartz wafer.

3. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The etched doped quartz wafer is subjected to micro-electromechanical machining to form a dual cantilever support structure, a cantilever beam is generated by a deep reactive ion etching process, and the mechanical properties of the cantilever support structure are optimized by combining a dynamic stress compensation technology, specifically including: Providing the etched doped quartz wafer and performing surface cleaning, removing the residual photoresist and etching byproducts on the wafer surface through an ultrasonic cleaning process; Performing photolithography patterning on the surface of the wafer, and forming a mask pattern of a dual cantilever beam on the surface of the wafer by a deep ultraviolet lithography machine; A cantilever beam structure was generated by using a deep reactive ion etching process. By controlling the etching gas flow and radio frequency power, a double cantilever beam with a width of 10 μm and a thickness of 5 μm was etched on the surface of the wafer. During the etching process, the wafer temperature was monitored by an infrared thermal imager. The mechanical properties of the cantilever beam are measured based on a laser vibrometer. The cantilever beam is stimulated to vibrate by applying a swept frequency signal, and the natural frequency and vibration mode data of the cantilever beam are collected.

4. The method for processing the automotive-grade SMD chip crystal according to claim 3, characterized in that: The method further includes measuring the mechanical properties of the cantilever beam based on a laser vibrometer, exciting the cantilever beam to vibrate by applying a sweep frequency signal, and collecting the natural frequency and vibration modal data of the cantilever beam. The stress distribution of the cantilever beam is simulated and optimized by using finite element analysis software. The stress cloud map of the cantilever beam is generated based on the vibration measurement data, the stress concentration area is identified, and a local repair plan is generated through the AI ​​algorithm. According to the simulation optimization results, femtosecond laser micromachining technology is used to locally trim the mass block at the end of the cantilever beam, so that the natural frequency of the cantilever beam is stabilized at 25kHz±5% and the stress distribution is uniform. The optimized cantilever beam structure was subjected to surface passivation treatment, and a 50 nm thick silicon nitride protective layer was formed on the surface of the cantilever beam by an atomic layer deposition process.

5. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The method of constructing a three-dimensional electromagnetic shielding layer on the surface of the wafer after cantilever processing, wherein a ceramic substrate and a metal conductive layer are alternately deposited by an additive manufacturing process, and the morphology of the three-dimensional electromagnetic shielding layer is calibrated in real time based on a visual detection system, specifically includes: Providing a wafer that has completed cantilever processing and performing surface pretreatment, wherein organic pollutants remaining on the surface of the wafer are removed by a plasma cleaning process; Laser induced metal deposition process is used to selectively ablate ceramic slurry through pulsed laser to form a ceramic matrix layer with a thickness of 20μm to construct a ceramic matrix layer on the surface of the wafer. A metal conductive layer is deposited on the surface of the ceramic substrate layer by aerosol jet printing technology, wherein copper nanoparticles are used as the conductive material, and a continuous conductive path with a thickness of 5 μm is formed by controlling the jet pressure and substrate temperature; The morphology of the metal conductive layer is calibrated in real time, and the surface of the conductive layer is scanned by a visual inspection system. If a hole or short circuit defect is detected, local laser repair is triggered.

6. The method for processing the automotive-grade SMD chip crystal according to claim 5, characterized in that: The morphology of the metal conductive layer is calibrated in real time, and the surface of the conductive layer is scanned by a visual inspection system. If a hole or short circuit defect is detected, a local laser repair is triggered, and then the following is included: The ceramic substrate and the metal conductive layer are deposited repeatedly to form a three-dimensional stacked structure with a total thickness of 50 μm to construct a three-dimensional electromagnetic shielding layer, wherein the interface between each layer of ceramic and metal is laser annealed to enhance the bonding strength; The three-dimensional electromagnetic shielding layer is surface-smoothed, and the electromagnetic shielding effectiveness of the shielding layer is verified based on a visual inspection system. The conductive path continuity and shielding effectiveness of the shielding layer are measured by a scanning electron microscope and an impedance analyzer. If the standards are not met, local additive repair is triggered.

7. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The polyimide-silicon dioxide colloidal material is provided, a gradient distribution of the glue layer is achieved by a microdroplet jetting technology, and a vibration spectrum simulation is applied for pre-curing treatment to coat a polyimide-silicon dioxide composite stress buffer layer on the ceramic substrate, specifically comprising: The polyimide prepolymer and the silica nanoparticles are mixed in a mass ratio of 3:1, and a uniform colloid is formed by high-speed stirring, and the bubbles are removed by filtering to obtain a polyimide-silica colloidal material; The colloidal material is sprayed onto the substrate surface in an array of microdroplets by a microdroplet jetting technique, the jetting pressure is 50-200 kPa, the substrate temperature is 25-80° C., the thickness of the glue layer is 20 μm, and the gradient distribution is from the wafer side to the substrate side, so as to coat the colloidal material on the ceramic substrate; Real-time monitoring of the glue layer morphology based on high-speed cameras, capturing the droplet spreading morphology, and dynamically adjusting the injection parameters in combination with the fluid mechanics model; Apply vibration spectrum simulation to the coated adhesive layer for pre-curing treatment, wherein 20-2000 Hz random vibration is applied by a piezoelectric exciter, and UV pre-curing is performed at the same time to make the adhesive layer initially cross-linked under stress; The pre-cured adhesive layer is subjected to a heat curing treatment, wherein the temperature is increased stepwise in a nitrogen environment, the temperature increasing stages are 80°C-150°C-200°C, and each stage is 1 hour, so that the adhesive layer is completely cured to form a polyimide-silicon dioxide composite stress buffer layer.

8. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The process of aligning the processed crystal with the substrate and performing SMD packaging, and dynamically calibrating and fine-tuning the cantilever structure based on the resonant frequency measurement, specifically includes: Prepare the processed crystal and the ceramic substrate for alignment, fix the crystal with a vacuum nozzle, and apply a 5μm thick temporary adhesive on the substrate to assist in fine-tuning the position during the alignment process; A force feedback bonding system is used for alignment, and the contact pressure between the crystal and the substrate is monitored in real time through a micro-force sensor. If the pressure exceeds the limit, the piezoelectric ceramic micro-displacement platform is triggered to perform position compensation. The airtight packaging is completed in a vacuum environment. After the crystal and substrate are bonded together, nitrogen is filled in and the packaging cavity is sealed by a laser welding process.

9. The method for processing the automotive-grade SMD chip crystal according to claim 1, characterized in that: The method further comprises: completing the airtight packaging in a vacuum environment, filling the crystal with nitrogen after bonding the crystal to the substrate, and sealing the packaging cavity by a laser welding process, and then: The cantilever structure is dynamically calibrated based on the resonant frequency measurement device, in which a sweep frequency signal is applied through a piezoelectric exciter, and the cantilever response is measured with a laser vibrometer to generate a frequency-amplitude curve. If the measured frequency deviates from the target value, the laser micromachining technology is triggered to perform local trimming of the mass block at the end of the cantilever. The surface of the packaged crystal is cleaned and marked, surface residues are removed by plasma cleaning, and the product number and batch information are laser engraved on the surface of the package.

10. An automotive grade SMD chip crystal, characterized in that: The automotive-grade SMD chip crystal is manufactured by the processing method of any one of claims 1 to 9, wherein the automotive-grade SMD chip crystal specifically comprises: Gradient doped quartz wafer, the surface of the wafer is formed into a gradient doped area through ion implantation process; A dual cantilever support structure is formed on the wafer surface by a deep reactive ion etching process; A three-dimensional electromagnetic shielding layer is formed by alternately depositing a ceramic matrix and a metal conductive layer on the surface of the cantilever structure through an additive manufacturing process to form a three-dimensional stacked structure with a total thickness of 50 μm; The composite stress buffer layer is formed by coating a polyimide-silicon dioxide colloidal material on a ceramic substrate by a microdroplet jetting technique; The airtight packaging layer, the crystal and the substrate are airtightly packaged through vacuum bonding and laser welding.

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