Thin intermediate structure for cross-blind hole and processing method thereof

Abstract

This invention belongs to the field of circuit board processing technology and discloses a thin-dielectric-thickness cross-blind via intermediate support structure and its processing method. The method includes: the inner layer is fabricated using conventional PCB processes; an intermediate support layer with pads is set in the cross-step region; windows are etched at the corresponding positions of the pads; and outer layer partition targets are simultaneously set; the outer layer is CFM etched with windows, and after lamination, laser ablation is used to form laser targets on the intermediate support layer; the outer layer is etched with windows by recognizing the laser targets; the laser identifies the partition targets of the inner layer support layer and performs cross-step blind via laser forming based on pre-positioning, supplemented by a via enlargement process to optimize the consistency of the via shape. This invention addresses the processing requirements of thin-dielectric-layer stepped blind vias by designing an intermediate support structure, solving the problems of easy breakage and signal instability in cross-step blind via connections under thin-dielectric-thickness conditions, improving the reliability and integration density of precision electronic devices, and meeting the high-performance requirements of miniaturized devices such as 5G communications and wearable devices.

Description

Technical Field

[0001] This invention belongs to the field of circuit board processing technology, and particularly relates to a thin-medium-thickness cross-blind via intermediate support structure and its processing method. Background Technology

[0002] Current methods for machining thin-medium, thick-layer blind vias primarily employ a combination of UV laser copper removal followed by CO2 laser cleaning. The process is as follows: First, UV laser copper removal is performed in two steps. The first step removes the surface copper foil to a predetermined depth, followed by a second step to refine the opening size and contour, avoiding damage to the thin dielectric layer. Then, CO2 laser cleaning is used to ablate any remaining slag and carbonized layer at the bottom of the via, ensuring a smooth and unobstructed hole bottom. This process is suitable for thin-medium, thick-layer vias, but the two-step UV removal increases the complexity of the process, and the CO2 cleaning introduces the risk of a heat-affected zone.

[0003] Based on the above analysis, the problems and defects of the existing technology are as follows: Due to the extremely thin medium, the laser energy / frequency / focus needs to be precisely matched, but this is affected by the characteristics of the medium, and parameter inaccuracies lead to abnormal hole shapes (over / under-ablation, slag residue, uneven hole diameter, and uncontrolled taper). The thin medium has poor rigidity, and the hole walls are easily collapsed due to uneven heating under laser impact. Irregular hole shapes weaken the interlayer bonding force, ultimately leading to separation. Summary of the Invention

[0004] To overcome the problems existing in related technologies, the present invention discloses a thin dielectric thick cross-blind via intermediate support structure and its processing method, which is particularly suitable for high density interconnect (HDI) circuit boards, semiconductor packaging substrates, multilayer flexible circuit boards and other fields.

[0005] The technical solution is as follows: A method for processing a thin-film, thick-film, cross-blind-hole intermediate support structure, including the following steps: S1, Inner layer fabrication, the inner layer is made using PCB process, an intermediate receiving layer with pads is set in the cross-step area, windows are etched at the corresponding positions of the pads, and outer layer partition targets are set simultaneously. S2, the outer layer is etched with CFM to open windows. After lamination, a laser ablation is used to form a laser target in the middle support layer. The outer layer is etched to open windows by recognizing the laser target. S3, cross-level hole processing, uses laser to identify the inner layer bearing layer partition target, and performs cross-level blind hole laser forming based on the pre-positioned location, supplemented by hole expansion process to optimize hole shape consistency.

[0006] In step S2, forming a laser target in the intermediate bearing layer by laser ablation includes: S201, synchronous ablation of positioning holes and blind holes; S202, laser parameter optimization.

[0007] Step S201, synchronous ablation of positioning holes and blind holes includes: simultaneously forming a laser target for subsequent mechanical drilling positioning in the intermediate bearing layer through laser ablation while drilling blind holes, thus forming positioning holes; the relationship between the diameter of the positioning hole and the positioning accuracy of the blind hole is as follows: In the formula, The diameter of the laser target in the intermediate support layer. This represents the optimal value verified through process experiments.

[0008] Step S202, laser parameter optimization includes: using The laser equipment controls the laser energy and the number of laser guns to ablate the positioning holes without damaging the inner positioning structure. The matching relationship between laser ablation energy and hole diameter is as follows: In the formula, The diameter of the positioning hole formed by laser ablation. This represents the mapping relationship between energy and the number of guns. The energy of a single pulse laser is given, and its value range is [value range missing]. ; This represents the number of laser pulse repetitions, with a value ranging from 2 to 5. This is the process coefficient, determined through experimental calibration.

[0009] In step S2, the outer layer performs etching to create a window by recognizing the laser target, including: Step 1, Multi-layer positioning window coordinated alignment; Inner layer positioning windows are set on the upper and lower copper layers of the inner layer board. After the outer layer board is laminated, outer layer positioning windows are opened at corresponding positions on the outer layer board. The inner layer positioning windows are exposed by laser ablation of the resin layer, forming an alignment funnel hole; The positioning window size constraint formula is: In the formula, This refers to the diameter of the positioning window in the inner layer of the lower copper layer. The diameter of the outer positioning window. The pad's side length and diameter; Step 2, laser target identification etching; when the outer layer is etched and windows are opened, the laser target is used as a reference, and the target position is identified through a high-precision alignment system to control the deviation of the etched area.

[0010] Furthermore, identifying the target location through a high-precision alignment system includes: After acquiring the target position signal during laser etching, a coordinate system transformation is performed to locate the target position. An improved Kalman filter is then applied, and the current estimated position of the etched area is directly output as the positioning position. This is achieved either by fitting the position using the least squares method or by directly outputting the current estimated position of the etched area as the positioning position. The formula for calculating the predicted value using the improved Kalman filter is as follows: In the formula, for The optimal result of the system state at any given time. Here is the state transition matrix. The etched area of ​​the target is approximately moving at a uniform speed. The sampling interval; In etching region positioning applications, a matrix is ​​formed by the optimal etching position, etching rate, and etching acceleration from the previous moment. The state transition matrix H is represented as ; Predicted value corresponding time The predicted covariance value is: In the formula, for The optimal result for time-varying covariance. The system process noise covariance; Improved Kalman Filter The gain value at time t is: In the formula, To improve Kalman filtering Gain value at time, This is the system measurement matrix, with values... ; To measure the noise covariance; The optimal state of the system at any given time is: In the formula, for The optimal value of the system state at any given time. for Time system measurement values; The covariance corresponding to the optimal result of the system at time step is: In the formula, for The covariance corresponding to the optimal result of the system at any given time; The target position positioning coordinate system transformation method employs the time difference of arrival (TDOA) positioning method for the etched areas at the target position. By measuring the time difference of the etching signal propagation from the etched area at the positioned target position to the processing center of the high-precision alignment system, the etching distance difference between the previous and next etched areas at the target position is obtained, thus achieving the positioning of the moving etched area. The etching distance of the etched area at different times at the measured target position is then used to determine the etch distance. , After that, the distance difference between the two is According to geometric principles, the etched area of ​​the located target position is centered on the previous etched area and the next etched area, and the distance difference to the two foci is [value missing]. On the hyperbola; where, ; This refers to the time it takes for the processing center of a high-precision alignment system to receive the reflected signal from the etched area of ​​a target position for the next positioning. The time it takes for the laser signal from the etched area of ​​the initially positioned target to reflect towards the processing center of the high-precision alignment system; For laser speed; The coordinates of the three etched regions at different times are The coordinates of the etched area at the target location are: Then we have: By solving the above two equations, the coordinates of the etched area of ​​the target position at the current location during the etching motion can be obtained.

[0011] In step 2, the etching deviation control formula is as follows: In the formula, The diameter of the laser target. This represents the offset between the outer etching window and the center of the laser target.

[0012] In step S3, performing cross-order blind hole laser forming based on pre-positioning includes: S301 features high-precision target recognition and dynamic alignment compensation; it employs a multispectral visual recognition system combined with AI algorithms to calibrate the inner layer bearing layer partitioned targets in real time. S302, segmented laser energy control; laser forming is divided into three stages: pre-piercing, fine-tuning, and taper control. By dynamically adjusting the laser pulse energy and frequency, the taper of the hole wall is controlled at 80°-90°. Dynamic adjustment of laser pulse energy includes: reducing from 10mJ to 6-7mJ; dynamic adjustment of laser pulse frequency includes: increasing to 200-300kHz; laser pulse scanning speed is optimized to 1-2m / s. S303 features multi-axis dynamic focusing; it integrates a six-axis motion platform and a real-time focus monitoring system to automatically adjust the laser focusing position for different layer thicknesses, ensuring consistent processing accuracy of cross-level holes across different layers.

[0013] In step S3, optimizing the hole shape consistency through the hole enlargement process includes: S01, layered progressive hole enlargement; the hole enlargement is divided into three stages: rough enlargement, fine finishing and polishing, with different combinations of laser parameters used in each stage; S02, plasma-assisted cleaning; after hole enlargement, a low-temperature plasma cleaning process is introduced to remove residual carbonized slag and oxide layer on the hole wall, thereby improving the adhesion of metallization in the hole. S03, AI-driven adaptive parameter adjustment; based on real-time monitored aperture data, the AI ​​system automatically adjusts the laser power, scanning path, and dwell time to achieve adaptive optimization of process parameters for different batches and materials; the AI ​​system automatically adjusts the laser power from 30W to 36-45W; the automatic adjustment of the scanning path adopts spiral scanning; the automatic adjustment of the dwell time includes: optimized to 0.5-1ms / aperture.

[0014] Another object of the present invention is to provide a thin-medium-thickness cross-blind-hole intermediate support structure, which is manufactured using the aforementioned processing method for the thin-medium-thickness cross-blind-hole intermediate support structure.

[0015] Combining all the above technical solutions, the beneficial effects of this invention are as follows: This invention addresses the processing requirements of stepped blind vias in thin dielectric layers by using an intermediate support structure design to solve the problems of easy breakage and signal instability in cross-step blind via connections under thin dielectric thickness, thereby improving the reliability and integration density of precision electronic devices and meeting the high-performance requirements of miniaturized devices such as 5G communications and wearable devices. This invention addresses the core pain points of cross-step blind vias with thin dielectric thickness (<150μm) by systematically solving the problems of insufficient alignment accuracy of upper and lower pads and poor consistency of blind via shape, simultaneously improving the reliability of blind via connections, and reducing operational difficulty by simplifying the processing flow.

[0016] Enhanced Product Diversity: Adaptable to dielectric thicknesses <150μm, the bonding layer and etched windows allow for flexible adjustment of pad size and target layout, supporting various product types such as HDI boards, semiconductor packaging substrates, and flexible boards, expanding the application scenarios of miniaturized electronic devices. Superior Processing Quality: Inner and outer layer etched windows + zoned targets achieve ±20μm alignment accuracy, the intermediate bonding layer suppresses laser parameter interference, and combined with via enlargement technology, hole shape consistency reaches over 95%, interlayer bonding strength is improved by 30%, and the hole wall collapse and separation defect rate is reduced to below 0.5%. Strong Process Compatibility: The inner layer uses conventional PCB processes, and the outer layer CFM etched windows and laser forming / via enlargement are compatible with existing equipment, requiring no new production lines. It can collaborate with special processes such as buried capacitors and resistors, and high-frequency materials, adapting to the processing of over 90% of mainstream thin and thick dielectric products. Optimized Electrical Performance: Regular hole shape and precise alignment reduce signal transmission loss by 20%, and impedance fluctuation is controlled within ±5%, meeting the high-frequency and high-speed requirements of 5G communication and wearable devices, improving the high-frequency stability of devices. Cost and efficiency balance: Replacing 3-5 extra processes with stacked blind holes reduces single-board processing time by 25% and material waste by 15%; pre-positioning improves yield and reduces overall cost by 18%, achieving high quality, low cost and high efficiency synergy. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the disclosure of this invention and, together with the description, serve to explain the principles of this disclosure; Figure 1 This is a flowchart of the processing method for the thin-medium-thickness cross-blind hole intermediate bearing structure provided in an embodiment of the present invention; Figure 2 This is a flowchart of cross-order blind hole laser forming based on pre-positioning provided in the embodiments of the present invention; Figure 3 This is a flowchart of the hole-forming process optimization for hole shape consistency provided in the embodiments of the present invention. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] Example 1: The present invention uses a method of laser forming after etching and pre-positioning a thin intermediate layer and an outer layer to process cross-level blind holes, while improving alignment accuracy through partitioned alignment.

[0020] like Figure 1As shown, the processing method for the thin-medium-thickness cross-blind hole intermediate bearing structure includes: S1, Inner layer fabrication, the inner layer is made using PCB process, an intermediate receiving layer with pads is set in the cross-step area, windows are etched at the corresponding positions of the pads, and outer layer partition targets are set simultaneously. S2, the outer layer is etched with CFM to open windows. After lamination, a laser ablation is used to form a laser target in the middle support layer. The outer layer is etched to open windows by recognizing the laser target. S3, cross-level hole processing, uses laser to identify the inner layer bearing layer partition target, and performs cross-level blind hole laser forming based on the pre-positioned location, supplemented by hole expansion process to optimize hole shape consistency.

[0021] For example, step S2, outer layer CFM etching window: after lamination, laser ablation is used to form a laser target in the intermediate bonding layer, including: S201, synchronous ablation of positioning holes and blind holes; while laser drilling blind holes, laser ablation is used to simultaneously form laser targets (positioning holes) in the intermediate bonding layer for subsequent mechanical drilling positioning, replacing the traditional positioning method of X-RAY target hitting after pressing, ensuring consistency of the through-blind hole positioning system.

[0022] The formula relating the diameter of the locating hole to the positioning accuracy of the blind hole is as follows: In the formula, The diameter of the laser target in the intermediate support layer. This represents the optimal value verified through process experiments, corresponding to the minimum deviation range (within ±0.1mm) of blind hole positioning accuracy.

[0023] Technical Logic and Verification. Reasonableness of Numerical Setting: This value is based on a comprehensive balance of the following process parameters: If the positioning hole is too small (<3.0mm): laser ablation is prone to causing edge burrs, affecting the accuracy of subsequent mechanical drilling; If the positioning hole is too large (>3.5mm): it will occupy the wiring space in the cross-step area and reduce the PCB wiring density; 3.2mm: while ensuring positioning accuracy, it also takes into account process stability and wiring efficiency.

[0024] Experimental verification data: By comparing the process effects of different positioning hole diameters, 3.2mm was verified as the optimal value: When the positioning hole diameter = 3.2mm, the misalignment rate of blind holes and through holes is ≤1%, meeting the high precision requirements of HDI boards; when the positioning hole diameter = 2.8mm, the misalignment rate increases to 3.5%, and edge burning of the positioning holes occurs; when the positioning hole diameter = 3.6mm, the wiring density decreases by 12%, and insufficient spacing between the positioning holes and the lines leads to short circuit risks. This application eliminates the deviation of traditional X-RAY targeting and laser positioning systems, solving the mismatch problem between through and blind holes; it simplifies the process flow, eliminating the need for additional targeting steps and reducing production costs.

[0025] S202, laser parameter optimization; employing CO2 laser equipment, by controlling laser energy and the number of laser guns, precisely ablates the positioning holes without damaging the inner positioning structure. The matching relationship between laser ablation energy and hole diameter: In the formula, The diameter of the positioning hole formed by laser ablation (unit: mm). This represents the mapping relationship between energy and the number of guns. The value is the single-pulse laser energy (unit: mJ), and the range is: ; This represents the number of laser pulse repetitions, with a value ranging from 2 to 5. The process coefficient is determined through experimental calibration, and the parameters within this range are verified through experiments to achieve accurate aperture control.

[0026] Technical logic and verification; The ablation capability of a single laser pulse is determined by the energy; the higher the energy, the greater the amount of material removed in a single ablation, and the larger the aperture. The cumulative ablation count of the laser pulse determines the depth and smoother the aperture. A linear superposition model allows for quantitative control of the aperture size, preventing damage to the inner positioning structure due to excessive energy or insufficient energy resulting in a small aperture and rough edges. Experimental data compares the ablation effects of different energy and energy combinations to verify the rationality of this parameter range. when At that time, aperture The edges have obvious burrs, and the positioning accuracy is insufficient; when At that time, aperture The edges are smooth, and the positioning accuracy meets the requirements; when At that time, aperture The large aperture occupies the wiring space in the cross-step area; the present invention avoids the inner positioning hole from being burned or deformed due to excessive laser intensity; improves the flatness of the positioning hole edge, and provides a precise reference for subsequent mechanical drilling.

[0027] Step S2 involves etching a window in the outer layer by identifying the laser target to enhance pre-positioning accuracy, including: Step 1: Multi-layer positioning window coordinated alignment; Inner layer positioning windows are set on the upper and lower copper layers of the inner layer board. After the outer layer board is laminated, an outer layer positioning window (with an area larger than the inner layer positioning window) is opened at the corresponding position on the outer layer board. The inner layer positioning window is exposed by laser ablation of the resin layer, forming an alignment funnel hole. Positioning window size constraint formula: In the formula, This refers to the diameter of the positioning window in the inner layer of the lower copper layer. The diameter of the outer positioning window. The pad side length and diameter are used to avoid direct damage to the inner layer positioning window during laser ablation; the alignment reference is enlarged through the funnel hole structure to improve the interlayer alignment accuracy to a minimum of 45μm (60μm in the traditional method).

[0028] Step 2, Laser Target Identification Etching: When etching windows in the outer layer, the laser target (positioning hole) is used as a reference, and the target position is identified through a high-precision alignment system to control the deviation of the etching area.

[0029] For example, identifying the target position using a high-precision alignment system includes: acquiring the target position signal during laser etching, then performing a target position coordinate system transformation, applying an improved Kalman filter, and directly outputting the current estimated position of the etched area as the positioning position, or fitting the position using the least squares method or directly outputting the current estimated position of the etched area as the positioning position; the improved Kalman filter includes: The formula for calculating the predicted value is: In the formula, for The optimal result of the system state at any given time. Here is the state transition matrix. The etched area of ​​the target is approximately moving at a uniform speed. The sampling interval; In etching region positioning applications, a matrix is ​​formed by the optimal etching position, etching rate, and etching acceleration from the previous moment. The state transition matrix H is represented as ; Predicted value corresponding time The predicted covariance value is: In the formula, for The optimal result for time-varying covariance. The system process noise covariance; Improved Kalman Filter The gain value at time t is: In the formula, To improve Kalman filtering Gain value at time, This is the system measurement matrix, with values... ; To measure the noise covariance; The optimal state of the system at any given time is: In the formula, for The optimal value of the system state at any given time. for Time system measurement values; The covariance corresponding to the optimal result of the system at time step is: In the formula, for The covariance corresponding to the optimal result of the system at any given time; The target position positioning coordinate system transformation method employs the time difference of arrival (TDOA) positioning method for the etched areas at the target position. By measuring the time difference of the etching signal propagation from the etched area at the positioned target position to the processing center of the high-precision alignment system, the etching distance difference between the previous and next etched areas at the target position is obtained, thus achieving the positioning of the moving etched area. The etching distance of the etched area at different times at the measured target position is then used to determine the etch distance. , After that, the distance difference between the two is According to geometric principles, the etched area of ​​the located target position is centered on the previous etched area and the next etched area, and the distance difference to the two foci is [value missing]. On the hyperbola; where, ; This refers to the time it takes for the processing center of a high-precision alignment system to receive the reflected signal from the etched area of ​​a target position for the next positioning. The time it takes for the laser signal from the etched area of ​​the initially positioned target to reflect towards the processing center of the high-precision alignment system; For laser speed; The coordinates of the three etched regions at different times are The coordinates of the etched area at the target location are: Then we have: By solving the above two equations, the coordinates of the etched area of ​​the target position at the current location during the etching motion can be obtained.

[0030] Experimental verification: Under complex lighting conditions, the above formula improves the target recognition rate from 60%-85% in traditional single-spectral imaging to 90%-98%, significantly enhancing the distinction between the target and the etched area. Traditional methods have an alignment accuracy of ±1.5 pixels (approximately ±15μm); the alignment accuracy of this invention is ±0.1 pixels (approximately ±1μm), meeting the alignment requirements of micro-holes smaller than 0.5mm in HDI boards.

[0031] Dynamic stability test. Test method: The adaptive alignment algorithm's compensation effect was tested by simulating vibrations in a production environment on a mechanical vibration table. Test results: Traditional method: Vibration caused alignment deviation to increase to ±3 pixels; this invention, through Kalman filtering compensation, controlled the alignment deviation within ±0.3 pixels, improving dynamic stability by 90%. Furthermore, this invention avoids the disappearance of tracking and positioning signals during the positioning process.

[0032] An example, the etching deviation control formula: In the formula, The diameter of the laser target. This represents the offset between the outer etched window and the center of the laser target. The core of this formula is to ensure that the etched window completely covers the center of the laser target, avoiding positioning failure due to etching offset.

[0033] like The etching window will deviate from the target center, causing subsequent mechanical drilling or circuit alignment deviations; if The etching window always includes the target center, ensuring positioning accuracy. Process verification: Experimental data from a high-precision alignment system verifies that when… At that time, the maximum allowable etching offset is 1.6mm; in actual production, by controlling the etching offset to ≤1.6mm, the alignment accuracy between the outer layer etching window and the inner layer positioning structure can be ensured to be ≤45μm (meeting the HDI board process requirements). This invention reduces the offset between the outer layer etching window and the inner layer positioning structure, improves the alignment accuracy of the circuit in the cross-step area, and reduces the risk of short circuits and open circuits caused by etching deviations.

[0034] In summary, step S2 verifies the experiment and its effects.

[0035] Through-hole and blind hole matching verification: By comparing the traditional X-ray target ablation and laser ablation positioning hole processes, the misalignment rate of through holes and blind holes was tested: Traditional process: through-hole and blind hole misalignment rate ≥5%, with the risk of hole breakage; Invented through-hole and blind hole misalignment rate ≤1%, with no hole breakage phenomenon, and the matching is significantly improved.

[0036] Interlayer alignment accuracy verification: The alignment accuracy of blind vias between layers was tested using a slicing analysis method. Traditional methods have a minimum alignment accuracy of 60μm; the minimum alignment accuracy of this invention is 45μm, meeting the process requirements of high-density HDI boards. Yield improvement verification: In mass production, the yield of the innovative process increased from 85% to 98%, mainly due to improved matching of through-hole and blind vias and significant control over etching deviation.

[0037] like Figure 2 As shown, exemplarily, in step S3, performing cross-order blind hole laser forming based on pre-positioning includes: S301 features high-precision target recognition and dynamic alignment compensation; it employs a multispectral visual recognition system combined with AI algorithms to calibrate the inner layer bearing layer partitioned targets in real time. S302, segmented laser energy control; laser forming is divided into three stages: pre-piercing, fine-tuning, and taper control. By dynamically adjusting the laser pulse energy and frequency, the taper of the hole wall is controlled at 80°-90°. Dynamic adjustment of laser pulse energy includes: reducing from 10mJ to 6-7mJ; dynamic adjustment of laser pulse frequency includes: increasing to 200-300kHz; laser pulse scanning speed is optimized to 1-2m / s. S303 features multi-axis dynamic focusing; it integrates a six-axis motion platform and a real-time focus monitoring system to automatically adjust the laser focusing position for different layer thicknesses, ensuring consistent processing accuracy of cross-level holes across different layers.

[0038] In step S302, segmented laser energy control involves dynamically adjusting the laser pulse energy, including reducing it to 60%-70% of that used in traditional processes, and decreasing it from 10mJ to 6-7mJ. The verification method, using SEM (scanning electron microscope) to observe the heat-affected zone of the pore wall, confirms a 50% reduction in thermal damage and an 80% reduction in the amount of residual carbonized slag on the pore wall. Dynamically adjusting the laser pulse frequency includes increasing it to 200-300kHz, compared to the traditional 100-150kHz. The verification method uses a high-speed camera to capture the laser ablation process, demonstrating a 30% improvement in hole shape consistency and a 40% increase in processing efficiency. The laser pulse scanning speed is optimized to 1-2 m / s (traditionally 0.5-1 m / s). The verification method uses a hole diameter measuring instrument to check that the hole diameter deviation is controlled below 2μm, a 50% improvement over traditional processes.

[0039] like Figure 3 As shown, for example, step S3, the hole enlargement process for optimizing hole shape consistency includes: S01, layered progressive hole enlargement; the hole enlargement is divided into three stages: rough enlargement, fine finishing and polishing. Each stage uses a different combination of laser parameters to avoid hole wall collapse or taper imbalance caused by one-time hole enlargement.

[0040] SO2, plasma-assisted cleaning: After pore enlargement, a low-temperature plasma cleaning process is introduced to remove residual carbonized slag and oxide layer on the pore wall, thereby improving the adhesion of pore metallization.

[0041] S03, AI-driven adaptive parameter adjustment: Based on real-time monitored hole shape data, the AI ​​system automatically adjusts the laser power, scanning path, and dwell time to achieve adaptive optimization of process parameters for different batches and materials. For example, in step S03, the AI ​​system automatically adjusts the laser power to 1.2-1.5 times that of traditional processes, increasing it from 30W to 36-45W; the verification method uses a hole diameter measuring instrument to verify that after hole enlargement, the hole diameter consistency is improved by 40%, and the hole wall roughness is reduced by 60%. Automatic scanning path adjustment includes: replacing traditional linear scanning with spiral scanning; the verification method uses a 3D profilometer to check that the hole wall taper deviation is controlled within ±3°, which is 50% better than the traditional process. Automatic dwell time adjustment includes: optimizing to 0.5-1ms / hole (traditionally 1-2ms / hole); the verification method uses SEM to observe the hole wall morphology, verifying a 70% reduction in hole wall thermal damage and an 85% reduction in residual burrs at the hole opening.

[0042] Experimental Verification. Hole Pattern Consistency Verification: Using a 3D profilometer and SEM (Scanning Electron Microscopy), statistical analysis was performed on the hole diameter, taper, and hole wall roughness of the same batch of multi-level holes, verifying that the standard deviation after process improvement was reduced by more than 50%. Reliability Verification: Through salt spray testing, thermal cycling testing (-55℃~125℃, 500 cycles), and electrical testing, it was verified that the adhesion of the hole metallization layer was improved by 30%, and the electrical connection reliability met the IPC-6012 Class 3 standard. Efficiency Verification: Compared with the traditional process, the improved single-board processing time was reduced by 35%, and the yield rate increased from 85% to 98%.

[0043] Example 2: The present invention provides a thin-medium-thickness cross-blind hole intermediate support structure, which is manufactured using a processing method for a thin-medium-thickness cross-blind hole intermediate support structure.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for processing a thin-medium, thick-diameter cross-blind hole intermediate support structure, characterized in that, This processing method Includes the following steps: S1, Inner layer fabrication, the inner layer is made using PCB process, an intermediate receiving layer with pads is set in the cross-step area, windows are etched at the corresponding positions of the pads, and outer layer partition targets are set simultaneously. S2, the outer layer is etched with CFM to open windows. After lamination, a laser ablation is used to form a laser target in the middle support layer. The outer layer is etched to open windows by recognizing the laser target. S3, cross-level hole processing, uses laser to identify the inner layer bearing layer partition target, and performs cross-level blind hole laser forming based on the pre-positioned location, supplemented by hole expansion process to optimize hole shape consistency.

2. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 1, characterized in that, In step S2, forming a laser target in the intermediate bearing layer by laser ablation includes: S201, synchronous ablation of positioning holes and blind holes; S202, laser parameter optimization.

3. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 2, characterized in that, Step S201, synchronous ablation of positioning holes and blind holes includes: simultaneously forming a laser target for subsequent mechanical drilling positioning in the intermediate bearing layer through laser ablation while drilling blind holes, thus forming positioning holes; the relationship between the diameter of the positioning hole and the positioning accuracy of the blind hole is as follows: In the formula, The diameter of the laser target in the intermediate support layer. This represents the optimal value verified through process experiments.

4. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 2, characterized in that, Step S202, laser parameter optimization includes: using The laser equipment controls the laser energy and the number of laser guns to ablate the positioning holes without damaging the inner positioning structure. The matching relationship between laser ablation energy and hole diameter is as follows: In the formula, The diameter of the positioning hole formed by laser ablation. This represents the mapping relationship between energy and the number of guns. The energy of a single pulse laser is given, and its value range is [value range missing]. ; This represents the number of laser pulse repetitions, with a value ranging from 2 to 5. This is the process coefficient, determined through experimental calibration.

5. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 1, characterized in that, In step S2, the outer layer performs etching to create a window by recognizing the laser target, including: Step 1, Multi-layer positioning window coordinated alignment; Inner layer positioning windows are set on the upper and lower copper layers of the inner layer board. After the outer layer board is laminated, outer layer positioning windows are opened at corresponding positions on the outer layer board. The inner layer positioning windows are exposed by laser ablation of the resin layer, forming an alignment funnel hole; The positioning window size constraint formula is: In the formula, This refers to the diameter of the positioning window in the inner layer of the lower copper layer. The diameter of the outer positioning window. The pad's side length and diameter; Step 2, laser target identification etching; when the outer layer is etched and windows are opened, the laser target is used as a reference, and the target position is identified through a high-precision alignment system to control the deviation of the etched area.

6. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 5, characterized in that, Identifying target location using a high-precision alignment system includes: After acquiring the target position signal during laser etching, a coordinate system transformation is performed to locate the target position. An improved Kalman filter is then applied, and the current estimated position of the etched area is directly output as the positioning position. This is achieved either by fitting the position using the least squares method or by directly outputting the current estimated position of the etched area as the positioning position. The formula for calculating the predicted value using the improved Kalman filter is as follows: In the formula, for The optimal result of the system state at any given time. Here is the state transition matrix. The etched area of ​​the target is approximately moving at a uniform speed. The sampling interval; In etching region positioning applications, a matrix is ​​formed by the optimal etching position, etching rate, and etching acceleration from the previous moment. The state transition matrix H is represented as ; Predicted value corresponding time The predicted covariance value is: In the formula, for The optimal result for time-varying covariance. The system process noise covariance; Improved Kalman Filter The gain value at time t is: In the formula, To improve Kalman filtering Gain value at time, This is the system measurement matrix, with values... ; To measure the noise covariance; The optimal state of the system at any given time is: In the formula, for The optimal value of the system state at any given time. for Time system measurement values; The covariance corresponding to the optimal result of the system at time step is: In the formula, for The covariance corresponding to the optimal result of the system at any given time; The target position positioning coordinate system transformation method employs the time difference of arrival (TDOA) positioning method for the etched areas at the target position. By measuring the time difference of the etching signal propagation from the etched area at the positioned target position to the processing center of the high-precision alignment system, the etching distance difference between the previous and next etched areas at the target position is obtained, thus achieving the positioning of the moving etched area. The etching distance of the etched area at different times at the measured target position is then used to determine the etch distance. , After that, the distance difference between the two is According to geometric principles, the etched area of ​​the located target position is centered on the previous etched area and the next etched area, and the distance difference to the two foci is [value missing]. On the hyperbola; where, ; This refers to the time it takes for the processing center of a high-precision alignment system to receive the reflected signal from the etched area of ​​a target position for the next positioning. The time it takes for the laser signal from the etched area of ​​the initially positioned target to reflect towards the processing center of the high-precision alignment system; For laser speed; The coordinates of the three etched regions at different times are The coordinates of the etched area at the target location are: Then we have: By solving the above two equations, the coordinates of the etched area of ​​the target position at the current location during the etching motion can be obtained.

7. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 5, characterized in that, In step 2, the etching deviation control formula is as follows: In the formula, The diameter of the laser target. This represents the offset between the outer etching window and the center of the laser target.

8. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 1, characterized in that, In step S3, performing cross-order blind hole laser forming based on pre-positioning includes: S301 features high-precision target recognition and dynamic alignment compensation; it employs a multispectral visual recognition system combined with AI algorithms to calibrate the inner layer bearing layer partitioned targets in real time. S302, segmented laser energy control; laser forming is divided into three stages: pre-piercing, fine-tuning, and taper control. By dynamically adjusting the laser pulse energy and frequency, the taper of the hole wall is controlled at 80°-90°. Dynamic adjustment of laser pulse energy includes: reducing from 10mJ to 6-7mJ; dynamic adjustment of laser pulse frequency includes: increasing to 200-300kHz; laser pulse scanning speed is optimized to 1-2m / s. S303 features multi-axis dynamic focusing; it integrates a six-axis motion platform and a real-time focus monitoring system to automatically adjust the laser focusing position for different layer thicknesses, ensuring consistent processing accuracy of cross-level holes across different layers.

9. The processing method of the thin-film thick-thickness cross-blind hole intermediate support structure according to claim 1, characterized in that, In step S3, optimizing the hole shape consistency through the hole enlargement process includes: S01, layered progressive hole enlargement; the hole enlargement is divided into three stages: rough enlargement, fine finishing and polishing, with different combinations of laser parameters used in each stage; S02, plasma-assisted cleaning; after hole enlargement, a low-temperature plasma cleaning process is introduced to remove residual carbonized slag and oxide layer on the hole wall, thereby improving the adhesion of metallization in the hole. S03, AI-driven adaptive parameter adjustment; based on real-time monitored aperture data, the AI ​​system automatically adjusts the laser power, scanning path, and dwell time to achieve adaptive optimization of process parameters for different batches and materials; the AI ​​system automatically adjusts the laser power from 30W to 36-45W; the automatic adjustment of the scanning path adopts spiral scanning; the automatic adjustment of the dwell time includes: optimized to 0.5-1ms / aperture.

10. A thin-medium, thick-thickness cross-blind-hole intermediate support structure, characterized in that, The structure is manufactured using the processing method described in any one of claims 1-9, which utilizes a thin-medium thickness cross-blind hole intermediate support structure.

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