Anti-CAF circuit board and processing method thereof

Abstract

The invention discloses an anti-CAF circuit board and a processing method thereof, through the synergistic effect of a micropore isolation ring, an interface strengthening layer and a sheet-shaped inorganic filler, a physical channel in which a conductive anode wire may form and spread is systematically blocked from three dimensions of spatial distance, interface state and bulk phase path. The micropore isolating ring directly increases the creepage distance between the copper conductors and effectively inhibits ion migration on the surface / near surface; in the interface reinforcing layer, the interface bonding force between a reinforcing material and a resin matrix blocks a core path of CAF (Computer Aided Framework) along a weak interface; and the dispersed sheet-shaped inorganic filler forms a zigzag physical barrier in the resin matrix, so that a potential in-vivo ion migration path is greatly prolonged. Therefore, the technical problem that ion migration along a CAF high-incidence path of a glass fiber bundle and a resin interface in a high-temperature and high-humidity environment cannot be completely inhibited by purely using a high-performance base material in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of circuit board processing technology, specifically to a CAF-resistant circuit board and its processing method. Background Technology

[0002] As electronic products become increasingly dense, powerful, and miniaturized, the spacing between conductors on printed circuit boards (PCBs) is shrinking, and the operating environment is becoming more demanding. Conductive anode filaments (CAFs) are a critical failure mode affecting the long-term reliability of PCBs. CAFs refer to the phenomenon where, under the combined influence of an electric field and a humid environment, copper ions migrate within or along the surface of the PCB's insulating substrate, eventually forming filamentary conductive paths between two conductive channels. This can lead to a decrease in insulation resistance or even a short circuit.

[0003] In existing technologies, methods to improve the resistance to carbon dioxide (CAF) on circuit boards mainly include: 1) using substrate materials with high glass transition temperature and low water absorption; 2) improving the resin system, such as using epoxy resin modification; and 3) optimizing the processing technology, such as ensuring the quality of the hole walls and strictly controlling the baking conditions. However, simply using high-performance substrates cannot completely suppress ion migration along the CAF-prone path—the interface between the glass fiber bundle and the resin—under high temperature and high humidity conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a CAF-resistant circuit board and its processing method, so as to solve the technical problem that the existing high-performance substrate alone cannot completely suppress ion migration along the high-incidence path of CAF at the interface of glass fiber bundle and resin under high temperature and high humidity environment.

[0005] The technical solution of this invention is implemented as follows:

[0006] On one hand, the present invention provides a CAF-resistant circuit board, comprising at least one conductive layer and at least one insulating layer, the insulating layer comprising a reinforcing material and a resin matrix, and further comprising at least one CAF barrier structure;

[0007] The CAF barrier structure includes a microporous isolation ring disposed on the conductive layer and surrounding the pad of the via.

[0008] An interface reinforcement layer is disposed on the surface of the reinforcing material of the insulating layer, and a sheet-like inorganic filler is dispersed in the resin matrix.

[0009] A further technical solution is that the microporous isolation ring is a ring-shaped copper-free region with a width ranging from 50 to 200 nanometers.

[0010] A further technical solution is that the interface reinforcement layer is a silicon dioxide or aluminum oxide coating with a thickness of 10-100 nanometers.

[0011] A further technical solution is that the sheet-like inorganic filler is boehmite or mica powder, with a particle size distribution of 1-5 nanometers, and its filling ratio in the resin matrix is ​​5%-20% of the resin weight.

[0012] A further technical solution is that the sheet-like inorganic filler is surface-treated with a silane coupling agent.

[0013] On the other hand, the present invention provides a method for processing a CAF-resistant circuit board, comprising the following steps:

[0014] S1. A copper-clad laminate is provided, wherein an interface reinforcement layer is formed on the surface of the insulating layer reinforcement material of the copper-clad laminate, and a sheet-like inorganic filler is mixed in the resin matrix.

[0015] S2. Perform pattern transfer and etching on the copper-clad laminate to form conductive lines and micro-hole isolation rings;

[0016] S3. Stack and laminate the treated boards, then drill holes to form through holes;

[0017] S4. Metallize the hole walls to form conductive holes;

[0018] S5. Surface treatment and post-curing.

[0019] A further technical solution is that step S2 specifically includes:

[0020] S21. A layer of photoresist is uniformly coated on the copper foil surface of the copper-clad laminate, and then a soft baking process is performed to form a photosensitive coating.

[0021] S22. The photosensitive coating is exposed in one go using a preset composite pattern film; the composite pattern film simultaneously includes a first pattern area for forming conductive lines and a second pattern area for forming microporous isolation rings.

[0022] S23. The exposed photosensitive coating is developed to dissolve and remove the unexposed parts, thereby forming an etch-resistant mask pattern on the copper foil surface that corresponds to the composite pattern.

[0023] S24. Using the resist mask pattern as a protective layer, chemically etch the exposed copper foil, then remove the resist mask, and simultaneously form conductive lines and micro-hole isolation rings surrounding the target hole pads on the copper-clad laminate.

[0024] A further technical solution is that step S3 specifically includes:

[0025] S31. Based on the circuit design, multiple inner core boards processed in step S2 and corresponding prepregs are positioned and stacked in a predetermined stacking order to form a multilayer board blank.

[0026] S32. The multilayer board blank is placed in a laminator and subjected to hot pressing under preset temperature, pressure and vacuum conditions to make the prepreg melt and flow and completely solidify, so as to firmly bond the layers into an integrated multilayer circuit board.

[0027] S33. Mark the drilling positions of the vias on the multilayer circuit board, and set the rotation speed and feed rate parameters of the drilling machine according to the board thickness, hole diameter and material characteristics.

[0028] S34. Perform mechanical drilling or laser drilling at the calibrated position to process through-holes that penetrate or partially penetrate the plate. The position of the through-holes is concentrically related to the pattern of the micro-hole isolation ring.

[0029] A further technical solution is that step S33 specifically includes:

[0030] S331. Read the design coordinates, hole diameter and type information of all the vias to be processed on the multilayer circuit board from the circuit design file;

[0031] S332. Based on the design coordinates, use an optical positioning system to identify preset reference marks on the multilayer circuit board and perform a system alignment operation between the physical position and the design coordinates.

[0032] S333. Based on the measured total thickness of the multilayer circuit board, the diameter of each through hole, and in combination with the material properties, the corresponding recommended values ​​for the spindle speed and feed rate of the drilling machine are generated by matching and calculating from the preset process parameter database.

[0033] S334. Load or input the drilling position coordinates and the calculated spindle speed and feed rate parameters into the CNC system of the drilling machine to complete the parameter setting before processing.

[0034] A further technical solution is that step S334 specifically includes:

[0035] S3341. Convert the drilling position coordinates and the calculated spindle speed and feed rate parameters into a standard NC program format that can be recognized by the drilling machine CNC system, and transmit it to the CNC system through the communication interface.

[0036] S3342. Call the NC program in the CNC system and use its simulation function to perform logical verification and graphical simulation of the drilling path, coordinates and parameters;

[0037] S3343. Load the verified NC program into the motion control unit and spindle control unit of the drilling machine, so that each unit is ready to execute the corresponding positioning and machining actions according to the program instructions.

[0038] S3344. Operate the CNC system interface and confirm that the machining program and parameters have been set as the current valid machining program, completing the final parameter setting before machining.

[0039] The beneficial effects of this invention are as follows:

[0040] By leveraging the synergistic effect of microporous isolation rings, interface reinforcement layers, and sheet-like inorganic fillers, the physical pathways through which conductive anode wires may form and propagate are systematically blocked from three dimensions: spatial distance, interface state, and bulk path. The microporous isolation rings directly increase the creepage distance between copper conductors, effectively suppressing surface / near-surface ion migration. The interface reinforcement layer enhances the interfacial bonding between the reinforcing material and the resin matrix, blocking the core path of CAF (Conductive Anode Failure) along this weak interface. Meanwhile, the dispersed sheet-like inorganic fillers construct a tortuous physical barrier within the resin matrix, significantly extending the potential bulk ion migration path. This solves the technical problem that existing methods using only high-performance substrates cannot completely suppress ion migration along the high-incidence path of CAF at the glass fiber bundle and resin interface under high temperature and humidity conditions. Attached Figure Description

[0041] Figure 1 This is a side view of a CAF-resistant circuit board according to the present invention;

[0042] Figure 2 This is a top view of a CAF-resistant circuit board according to the present invention;

[0043] Figure 3 This is a flowchart illustrating the processing steps of a CAF-resistant circuit board according to the present invention.

[0044] In the figure, 1 is the conductive layer; 2 is the insulating layer; 3 is the microporous isolation ring; and 4 is the interface reinforcement layer. Detailed Implementation

[0045] To better understand the technical content of this invention, specific embodiments are provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0046] See Figures 1 to 2 On one hand, the present invention provides a CAF-resistant circuit board, comprising at least one conductive layer 1 and at least one insulating layer 2, wherein the insulating layer 2 comprises a reinforcing material and a resin matrix, and further comprises at least one CAF barrier structure; the CAF barrier structure comprises a microporous isolation ring 3 disposed on the conductive layer 1 and surrounding the pad of the via; an interface reinforcement layer 4 disposed on the surface of the reinforcing material of the insulating layer 2, and a sheet-like inorganic filler dispersed in the resin matrix.

[0047] Specifically, the microporous isolation ring 3, by etching a ring-shaped copper-free area around the pads on the inner conductive layer 1, directly increases the linear spatial distance and creepage distance along the surface between adjacent conductive components (such as pads and adjacent wires) geometrically. Following the basic principle of "distance-resistant electromigration," even in a humid environment, ions find it difficult to cross this deliberately enlarged physical isolation area under the drive of an electric field, thus effectively suppressing the formation of CAF on or near the surface. The nanoscale dense coating, on the one hand, is difficult for ions to penetrate due to its excellent chemical inertness and physical barrier properties; on the other hand, it improves the interfacial bonding between the hydrophilic reinforcing material and the hydrophobic resin matrix, reducing microcracks and microgaps caused by mismatched thermal expansion coefficients or curing shrinkage. This fundamentally blocks the path most prone to CAF occurrence and propagation—the weak interface between the reinforcing material and the resin—greatly improving the insulation integrity of the interfacial region. The plate-like fillers are randomly dispersed in the matrix, and their plate-like morphology constitutes a large number of discontinuous and tortuous physical barriers. When potential ions attempt to migrate within the resin phase, they are forced to detour around these sheet-like barriers, exponentially increasing the actual migration path length and significantly increasing migration resistance. This makes it more difficult for ions to migrate within the resin bulk phase, and even with trace amounts of moisture penetrating the resin, it is difficult to form continuous conductive channels.

[0048] In this embodiment of the invention, the synergistic effect of the microporous isolation ring 3, the interface reinforcement layer 4, and the sheet-like inorganic filler systematically blocks the physical channels through which conductive anode wires may form and spread, from three dimensions: spatial distance, interface state, and bulk path. The microporous isolation ring 3 directly increases the creepage distance between copper conductors, effectively suppressing surface / near-surface ion migration; the interface reinforcement layer 4 enhances the interfacial bonding force between the reinforcing material and the resin matrix, blocking the core path of CAF occurring along this weak interface; and the dispersed sheet-like inorganic filler constructs a tortuous physical barrier within the resin matrix, greatly extending the potential bulk ion migration path. This solves the technical problem that existing methods using only high-performance substrates cannot completely suppress ion migration along the high-incidence path of CAF at the glass fiber bundle and resin interface under high temperature and humidity conditions.

[0049] Preferably, the microporous isolation ring 3 is a ring-shaped copper-free region with a width ranging from 50 to 200 nanometers.

[0050] Specifically, the microvia isolation ring 3 is a copper-free annular region etched onto the inner conductive layer 1, surrounding the via pads. The core function of this structure is to actively increase the insulation distance between adjacent conductors physically. When the circuit board is in a high-temperature, high-humidity environment with a potential difference, copper ions may migrate between conductors. The 50-200 nanometer width range is an optimized size, sufficient to effectively truncate initial ion migration channels at the nanoscale that may be induced by surface contaminants, moisture adsorption, or extremely thin oxide layers. This forces any potential surface ion migration path to bypass this isolation ring, significantly increasing the path length and energy barrier required for migration. Simultaneously, this nanometer-scale width is precisely controlled to maximize wiring space savings while providing insulation enhancement, avoiding excessive sacrifice of circuit wiring density due to an overly wide isolation ring. Therefore, the microvia isolation ring 3, by forming a controllable insulating gap, directly improves the local insulation reliability between conductors, especially between vias and wires, and between vias in high-density designs, serving as the first effective physical barrier to suppress CAF (Conductive Availability Fluidization).

[0051] Preferably, the interface reinforcement layer 4 is a silicon dioxide or aluminum oxide coating with a thickness of 10-100 nanometers.

[0052] Specifically, the interface reinforcement layer 4 is a dense coating of silica or alumina with a thickness of 10-100 nanometers formed on the surface of the reinforcing material (such as fiberglass cloth) of the insulating layer 2.

[0053] First, both silica and alumina are chemically stable, low dielectric constant, and non-hygroscopic inert inorganic materials. When they are applied as a coating to the surface of a reinforcing material, they can fundamentally change the chemical and physical environment of the original interface region. On the one hand, they have excellent barrier properties against the diffusion and penetration of moisture and ions; on the other hand, they can block the adsorption and transport of moisture and ions by active sites (such as silanol groups) that may exist on the surface of the reinforcing material.

[0054] Secondly, a thickness range of 10-100 nanometers represents a balance between effective protection and process feasibility. This thickness is sufficient to form a continuous, defect-free physical barrier film on the surface of the reinforcing material, completely covering the microscopic roughness and pores on the fiber surface. This eliminates the initial micro-gaps (preferred channels for CAF) formed at the interface due to differences in the coefficients of thermal expansion during the resin matrix curing process. Simultaneously, this nanoscale thickness ensures that the coating provides excellent barrier properties without increasing the overall thickness of the insulation layer 2 or affecting its mechanical properties. Furthermore, it maintains good interfacial compatibility with the resin matrix, preventing a decrease in adhesion to the resin due to excessive coating thickness.

[0055] Preferably, the flaky inorganic filler is boehmite or mica powder with a particle size distribution of 1-5 nanometers, and its filling ratio in the resin matrix is ​​5%-20% of the resin weight.

[0056] Specifically, the sheet-like inorganic filler is selected from boehmite (γ-AlOOH) or mica powder. Its core mechanism of action is to utilize the synergistic effect of its sheet-like morphology, nanoscale and appropriate volume filling to physically modify the resin matrix in order to construct an efficient three-dimensional barrier network.

[0057] Both boehmite and mica powder possess natural or processed lamellar crystalline structures. When uniformly dispersed in a resin matrix, these lamellar fillers act as numerous tiny, randomly oriented "baffles." When potential ions (such as Cu²⁺) attempt to migrate through the hygroscopic resin matrix under an electric field, they are forced to repeatedly circumvent these non-conductive lamellar barriers, thus lengthening the actual migration path and increasing the resistance that must be overcome. A particle size range of 1-5 nanometers ensures that the filler achieves a sufficiently large aspect ratio (lamellar characteristics) to effectively extend the migration path while maintaining good and stable dispersion in the resin, avoiding localized defects or stress concentrations caused by filler agglomeration. It serves as an effective physical barrier without excessively negatively impacting the resin's flowability, curing, and mechanical properties. A filler content of 5%-20% (by resin weight) is the critical range for achieving an effective "percolation network." When the filler content is below the lower limit of this range, the number of sheet fillers is insufficient, making it difficult to form a continuous and effective three-dimensional barrier network in the resin matrix, and ions can still find relatively direct migration channels. When the filler content reaches and is optimized within this range, the filler is sufficient to form a dense and interwoven barrier system in the matrix. At the same time, this upper limit of the ratio is designed to achieve a balance between achieving optimal barrier performance and maintaining the basic processability (such as viscosity and lamination filling properties) and mechanical toughness of the resin matrix, avoiding embrittlement of the composite material or deterioration of the process due to excessive filler.

[0058] Preferably, the sheet-like inorganic filler is surface-treated with a silane coupling agent.

[0059] Specifically, based on organic-inorganic interface chemical modification, the filler is optimized and stably bonded in the resin matrix, thereby enhancing its resistance to CAF.

[0060] In one example, silane coupling agents are a class of organosilicon compounds with dual reactive functional groups, whose general molecular formula is YR-Si(OR')3. Here, Y represents an organic functional group (such as amino or epoxy groups) that can chemically bond or strongly interact with organic resins (such as epoxy resins), R is a stable alkyl chain, and -Si(OR')3 is a hydrolyzable inorganic functional group. During surface treatment, the -Si(OR')3 group first hydrolyzes to generate active silanol groups (-SiOH). These silanol groups then undergo a condensation reaction with the hydroxyl groups (-OH) on the surface of sheet-like inorganic fillers such as boehmite or mica powder, forming a strong Si-O-filler covalent bond, thereby grafting an organic molecular layer with alkyl chains R as spacers and Y functional groups at the ends onto the filler surface. By chemically constructing an amphiphilic molecular layer on the surface of the inorganic filler, this molecular layer is anchored to the filler surface by chemical bonds and tightly bound to the resin matrix through chemical reactions or physical interactions. The microscopic interface structure of the composite material was optimized, ensuring that the sheet filler could fully perform its barrier function, while avoiding interface defects from becoming new weak points in the CAF, thereby improving the reliability and durability of the entire CAF barrier structure.

[0061] refer to Figure 3 On the one hand, the present invention provides a method for processing a CAF-resistant circuit board, comprising the following steps:

[0062] S1: Provides a copper-clad laminate, wherein an interface reinforcement layer 4 is formed on the surface of the insulating layer 2 reinforcing material of the copper-clad laminate, and the resin matrix contains flake-shaped inorganic fillers.

[0063] S2: Perform pattern transfer and etching on the copper-clad laminate to form conductive lines and micro-hole isolation rings 3;

[0064] S3: Stack and laminate the treated boards, then drill holes to form through holes;

[0065] S4: Metallize the hole wall to form a conductive hole;

[0066] S5: Surface treatment and post-curing.

[0067] Specifically, by pre-forming an interface reinforcement layer 4 (such as a nano-silica coating) on ​​the surface of the reinforcing material of the insulating layer 2, and pre-mixing lamellar inorganic fillers (such as boehmite) in the resin matrix, the two core elements constituting the CAF barrier are ensured: the reinforced interface and the bulk labyrinth structure are introduced from the substrate stage, providing a material platform with intrinsic CAF resistance potential for subsequent processing. Using photolithography and etching techniques, micro-hole isolation rings 3 are etched around the future via pad locations while forming conventional conductive circuit patterns. This achieves integrated molding of electrical interconnection and physical isolation, actively creating increased insulating gaps between conductors, which is the first structural defense against surface / near-surface ion migration. The lamination process firmly bonds the pre-fabricated layers under hot pressing, where the pre-mixed lamellar fillers are fixed in the resin flow, forming a three-dimensional barrier network; while the pre-fabricated interface reinforcement layer 4 is permanently encapsulated between the resin and the reinforcing material. Subsequently, drilling and hole metallization treatments (such as chemical copper plating and electroplating) form electrically conductive hole walls. The drilling location and the resulting microporous isolation ring 3 pattern must be aligned so that the final metallized hole walls are strictly confined to the inside of the isolation ring, thereby ensuring that the insulating function of the isolation ring is fully preserved and effective. The post-curing process is carried out at a temperature higher than the resin's glass transition temperature. Its principle is to promote full and final cross-linking of the resin, release lamination and internal stress generated during processing, and remove residual volatile components and moisture. This is crucial for ensuring optimal and stable interfacial bonding between the interface reinforcement layer 4 and the resin / reinforcing material, as well as between the resin matrix and the sheet filler, thereby curing and maximizing the long-term reliability of the entire CAF barrier structure.

[0068] Preferably, step S2 specifically includes:

[0069] S21. A layer of photoresist is uniformly coated on the copper foil surface of the copper-clad laminate, followed by soft baking to form a photosensitive coating.

[0070] S22. A pre-set composite pattern film is used to expose the photosensitive coating in one go; the composite pattern film simultaneously includes a first pattern area for forming conductive lines and a second pattern area for forming microporous isolation rings 3.

[0071] S23. The exposed photosensitive coating is developed to dissolve and remove the unexposed parts, thereby forming an etch-resistant mask pattern corresponding to the composite pattern on the copper foil surface.

[0072] S24. Using the resist mask pattern as a protective layer, chemically etch the exposed copper foil, then remove the resist mask, and simultaneously form conductive lines and micro-hole isolation rings 3 around the target hole pads on the copper-clad board.

[0073] Specifically, a uniform, controllable-thickness, temporary organic thin film (photoresist) with specific photochemical sensitivity is constructed on the surface of copper foil. The soft baking process removes the solvent from the photoresist layer, allowing it to solidify and set, thereby obtaining stable physical and photochemical properties and providing a reliable, defect-free imaging medium for subsequent high-precision pattern transfer. Using a radiation source such as ultraviolet light, the photosensitive coating is selectively irradiated through a pre-designed composite pattern film. This film integrates a first patterned area (defining conductive lines) and a second patterned area (defining micro-via isolation ring 3). This triggers a photochemical reaction (such as cross-linking or decomposition) in the irradiated area of ​​the photoresist material, forming a potential pattern within the photoresist layer. This ensures that the relative positional relationship between the conductive lines and the micro-via isolation ring 3 is determined during the optical projection stage, fundamentally eliminating alignment errors that may result from multiple exposures and guaranteeing that the isolation ring surrounds the pads of the future via locations. By using a specific developer, the resist layer portions whose solubility changes after exposure are selectively dissolved and removed (for positive photoresist, the exposed portion is removed; for negative photoresist, the unexposed portion is removed), based on the difference in photoresist solubility in different solvents caused by photochemical reactions. The result is a faithful reproduction of the composite pattern film design on the copper foil surface, forming an etch-resistant mask pattern composed of remaining photoresist. This mask simultaneously covers the copper foil areas to be retained (future conductive lines and pads) and the copper foil areas to be etched (the locations where microvia isolation rings 3 will form). The formed etch-resistant mask acts as a protective layer, selectively removing the copper foil not covered by the mask. The etchant (such as acidic copper chloride or alkaline ammonia etchant) reacts chemically with the exposed copper, dissolving it, while the copper protected by the mask is retained. After etching, the useless etch-resistant mask is removed by chemical stripping or dissolution. The final principle result of this step is that, in the same etching process, the final conductive line pattern is formed, and the designed microvia isolation rings 3 are fabricated around all target via pads. The ring-shaped copper-free area is integrally formed with the conductive line, laying the physical foundation for its CAF protection function of increasing creepage distance and inhibiting surface ion migration.

[0074] Preferably, step S3 specifically includes:

[0075] S31. Based on the circuit design, multiple inner core boards processed in step S2 and corresponding prepregs are positioned and stacked in a predetermined stacking order to form a multilayer board blank.

[0076] S32. Place the multilayer board blank in a laminator and perform hot pressing under preset temperature, pressure and vacuum conditions to melt and flow the prepreg and completely solidify it, firmly bonding each layer into an integrated multilayer circuit board.

[0077] S33. Mark the drilling positions of the vias on the multilayer circuit board, and set the drilling speed and feed rate parameters of the drilling machine according to the board thickness, hole diameter and material characteristics.

[0078] S34. Perform mechanical drilling or laser drilling at the calibrated position to process through-holes that penetrate or partially penetrate the plate. The position of the through-holes is concentrically related to the shape of the micro-hole isolation ring 3.

[0079] Specifically, based on the electrical connection and insulation requirements of the circuit, single-sided or double-sided inner core boards (containing patterns) after S2 treatment are physically stacked with prepreg as the adhesive medium, according to strict interlayer alignment. Optical or mechanical positioning systems ensure that the patterns on each core board (especially the positions of pads that will be connected in the future) are aligned in three-dimensional space, thus forming an uncured "multilayer board blank" with determined pattern positions. The board blank is placed in a laminator that provides a combined heat, pressure, and vacuum environment. At a preset high temperature, the resin in the prepreg melts and flows, wetting and filling the microscopic voids and pattern gaps on the core board surface; under pressure, the layers are tightly compacted, expelling air bubbles and volatiles; the vacuum environment further assists in removing air and preventing voids. Subsequently, under continuous heat, the resin undergoes an irreversible cross-linking and curing reaction, transforming from a viscous flow state to a hard solid state, thereby permanently bonding multiple independent core boards into an integrated multilayer circuit board.

[0080] Next, the high-precision hole machining undergoes a digital and parameterized intelligent control process. This involves two aspects: first, spatial coordinate calibration, which involves determining the center coordinates of each via on the pre-formed multilayer circuit board based on design data. This is typically achieved by reading the design file and aligning the equipment coordinate system with the board's reference points; second, matching and setting machining dynamic parameters, which involves calculating the optimal spindle speed and feed rate based on the actual total thickness of the multilayer board, the target hole diameter, and the specific material properties including the interface reinforcement layer 4 and fillers, using empirical formulas or database matching.

[0081] Finally, the drilling machine (mechanical drill bit or laser beam) removes material at the designated location on the plate according to the coordinates and parameters set in S33, forming a through hole or blind hole. The physical principle of this process is cutting and grinding for mechanical drilling, and ablation and vaporization for laser drilling. It is ensured that the metallized hole wall (conductive channel) is confined inside the isolation ring, allowing the isolation ring to be fully exposed and fulfill its design function of increasing creepage distance, preventing CAF from migrating along the surface from the hole wall to adjacent conductors.

[0082] Preferably, step S33 specifically includes:

[0083] S331. Read the design coordinates, hole diameter and type information of all the vias to be processed on the multilayer circuit board from the circuit design file;

[0084] S332. Based on the design coordinates, use an optical positioning system to identify preset reference marks on the multilayer circuit board and perform a system alignment operation between the physical position and the design coordinates.

[0085] S333. Based on the measured total thickness of the multilayer circuit board, the diameter of each through hole, and in combination with the material properties, the corresponding recommended values ​​for the spindle speed and feed rate of the drilling machine are generated by matching and calculating from the preset process parameter database.

[0086] S334. Load or input the drilling position coordinates and the calculated spindle speed and feed rate parameters into the CNC system of the drilling machine to complete the parameter setting before machining.

[0087] Specifically, the electronic data source of the circuit design (such as Gerber files or ODB++ files) is parsed and extracted to accurately read the design coordinates (X, Y), aperture size (D), and type information (such as through holes and blind holes) of all vias to be processed. A high-precision optical positioning system (such as a CCD camera) is used to actively scan and identify pre-fabricated reference marks on the multilayer circuit board. The system calculates the imaging position of the physical marks and compares and calculates them with the corresponding reference coordinates in the design data to automatically compensate for placement deviations, scaling errors, or micro-deformations that may occur during the processing of the board material.

[0088] Next, intelligent parameter decisions are made based on the real-time perceived state of the machining object and a pre-set process knowledge base. Specifically, the measured total plate thickness (rather than theoretical values, to eliminate the influence of lamination tolerances) and the diameter of each hole are first obtained, combined with the composite material properties (such as hardness, toughness, glass transition temperature, etc., which affect drilling force and heat) of the interface reinforcement layer 4 and the lamellar filler. Then, using multi-dimensional information as input conditions, the pre-set process parameter database is queried or called (this database is built based on historical machining data and materials science principles). Through embedded algorithms or empirical models, the optimal combination of recommended spindle speed and feed rate is matched and calculated. The two types of information generated in the previous steps and verified and optimized, spatial position information (coordinates) and dynamic control information (speed and feed rate), are integrated and loaded into the CNC system of the drilling machine.

[0089] Preferably, step S334 specifically includes:

[0090] S3341. Convert the drilling position coordinates and the calculated spindle speed and feed rate parameters into a standard NC program format that can be recognized by the drilling machine CNC system, and transmit it to the CNC system through the communication interface.

[0091] S3342. Call the NC program in the CNC system and use its simulation function to perform logical verification and graphical simulation of the drilling path, coordinates and parameters.

[0092] S3343. Load the verified NC program into the motion control unit and spindle control unit of the drilling machine, so that each unit is ready to execute the corresponding positioning and machining actions according to the program instructions.

[0093] S3344. Operate the CNC system interface, confirm that the machining program and parameters have been set as the current valid machining program, and complete the final parameter setting before machining.

[0094] Specifically, the drilling position coordinates, spindle speed, and feed rate parameters generated in step S333, existing in the form of general data or algorithms, are compiled or packaged into standardized NC (numerical control) program code according to the syntax and structure specified by the specific CNC system. This conversion process follows ISO standards or proprietary protocols of equipment manufacturers. Subsequently, the NC program file is transmitted to the CNC system of the drilling machine via a wired or wireless communication interface. The internal or supporting software of the CNC system calls the received NC program and utilizes its built-in simulation function. This function, through software algorithms, virtually executes all instructions in the program without triggering any actual mechanical actions. Its verification principle is mainly reflected in two aspects: first, logical verification, checking the code syntax, whether the coordinate values ​​exceed the travel limit, whether the spindle speed and feed rate are within the allowable range of the equipment, and whether the drilling sequence is reasonable, to prevent equipment failure or machine collision due to data errors or conflicts; second, graphical simulation, dynamically displaying the theoretical movement path of the drill bit, the drilling position on the plate, and the processing parameters at each position in the form of 3D animation on the computer screen. Operators can visually check whether the drilling path covers all designed hole positions, whether there is any abnormal movement, and whether it interferes with the plate boundary or other structures through a visual interface. The principle of this step is to build a "digital twin" pre-simulation environment to proactively identify and eliminate potential risks, ensuring that the processing path is completely consistent with the design intent.

[0095] The CNC system, acting as the central processing unit, parses and distributes the verified NC program to two key underlying control units: the motion control unit and the spindle control unit. The motion control unit is responsible for receiving coordinate commands and controlling the movement of the servo motors on the X, Y, and Z linear axes to achieve drill bit positioning; the spindle control unit is responsible for receiving spindle speed commands and controlling the rotational speed of the spindle motor.

[0096] The operator actively checks and confirms through the CNC system's human-machine interface whether the currently selected machining program is the NC program that was just loaded, and at the same time verifies whether the key parameters displayed on the interface, such as coordinates, spindle speed, and feed rate, match the design values. By pressing the "Program Selection Confirmation" or similar function key, the operator manually completes the final activation of the program.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A CAF-resistant circuit board, characterized in that, It includes at least one conductive layer and at least one insulating layer, the insulating layer comprising a reinforcing material and a resin matrix, characterized in that it further includes at least one CAF barrier structure; The CAF barrier structure includes a microporous isolation ring disposed on the conductive layer and surrounding the pad of the via. An interface reinforcement layer is disposed on the surface of the reinforcing material of the insulating layer, and a sheet-like inorganic filler is dispersed in the resin matrix.

2. The CAF-resistant circuit board according to claim 1, characterized in that, The microporous isolation ring is a ring-shaped copper-free region with a width ranging from 50 to 200 nanometers.

3. The CAF-resistant circuit board according to claim 1, characterized in that, The interface reinforcement layer is a silicon dioxide or aluminum oxide coating with a thickness of 10-100 nanometers.

4. The CAF-resistant circuit board according to claim 1, characterized in that, The sheet-like inorganic filler is boehmite or mica powder with a particle size distribution of 1-5 nanometers, and its filling ratio in the resin matrix is ​​5%-20% of the resin weight.

5. A CAF-resistant circuit board according to claim 4, characterized in that, The sheet-like inorganic filler is surface-treated with a silane coupling agent.

6. A method for processing a CAF-resistant circuit board according to any one of claims 1-5, characterized in that, Includes the following steps: S1. A copper-clad laminate is provided, wherein an interface reinforcement layer is formed on the surface of the insulating layer reinforcement material of the copper-clad laminate, and a sheet-like inorganic filler is mixed in the resin matrix. S2. Perform pattern transfer and etching on the copper-clad laminate to form conductive lines and micro-hole isolation rings; S3. Stack and laminate the treated boards, then drill holes to form through holes; S4. Metallize the hole walls to form conductive holes; S5. Surface treatment and post-curing.

7. The method for processing a CAF-resistant circuit board according to claim 6, characterized in that, Step S2 specifically includes: S21. A layer of photoresist is uniformly coated on the copper foil surface of the copper-clad laminate, and then a soft baking process is performed to form a photosensitive coating. S22. The photosensitive coating is exposed in one go using a preset composite pattern film; the composite pattern film simultaneously includes a first pattern area for forming conductive lines and a second pattern area for forming microporous isolation rings. S23. The exposed photosensitive coating is developed to dissolve and remove the unexposed parts, thereby forming an etch-resistant mask pattern on the copper foil surface that corresponds to the composite pattern. S24. Using the resist mask pattern as a protective layer, chemically etch the exposed copper foil, then remove the resist mask, and simultaneously form conductive lines and micro-hole isolation rings surrounding the target hole pads on the copper-clad laminate.

8. A method for processing a CAF-resistant circuit board according to claim 6, characterized in that, Step S3 specifically includes: S31. Based on the circuit design, multiple inner core boards processed in step S2 and corresponding prepregs are positioned and stacked in a predetermined stacking order to form a multilayer board blank. S32. The multilayer board blank is placed in a laminator and subjected to hot pressing under preset temperature, pressure and vacuum conditions to make the prepreg melt and flow and completely solidify, so as to firmly bond the layers into an integrated multilayer circuit board. S33. Mark the drilling positions of the vias on the multilayer circuit board, and set the rotation speed and feed rate parameters of the drilling machine according to the board thickness, hole diameter and material characteristics. S34. Perform mechanical drilling or laser drilling at the calibrated position to process through-holes that penetrate or partially penetrate the plate. The position of the through-holes is concentrically related to the pattern of the micro-hole isolation ring.

9. A method for processing a CAF-resistant circuit board according to claim 8, characterized in that, Step S33 specifically includes: S331. Read the design coordinates, hole diameter and type information of all the vias to be processed on the multilayer circuit board from the circuit design file; S332. Based on the design coordinates, use an optical positioning system to identify preset reference marks on the multilayer circuit board and perform a system alignment operation between the physical position and the design coordinates. S333. Based on the measured total thickness of the multilayer circuit board, the diameter of each through hole, and in combination with the material properties, the corresponding recommended values ​​for the spindle speed and feed rate of the drilling machine are generated by matching and calculating from the preset process parameter database. S334. Load or input the drilling position coordinates and the calculated spindle speed and feed rate parameters into the CNC system of the drilling machine to complete the parameter setting before processing.

10. A method for processing a CAF-resistant circuit board according to claim 9, characterized in that, Step S334 specifically includes: S3341. Convert the drilling position coordinates and the calculated spindle speed and feed rate parameters into a standard NC program format that can be recognized by the drilling machine CNC system, and transmit it to the CNC system through the communication interface. S3342. Call the NC program in the CNC system and use its simulation function to perform logical verification and graphical simulation of the drilling path, coordinates and parameters; S3343. Load the verified NC program into the motion control unit and spindle control unit of the drilling machine, so that each unit is ready to execute the corresponding positioning and machining actions according to the program instructions. S3344. Operate the CNC system interface and confirm that the machining program and parameters have been set as the current valid machining program, and complete the final parameter setting before machining.

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