Double-sided copper-embedded symmetric structure double-sided circuit board and its manufacturing method

Abstract

This application relates to the technical field of circuit board preparation. Specifically, it discloses a double-sided circuit board with a double-sided copper-embedded symmetric structure and its preparation method, including: providing and processing a first copper-clad core board and a second copper-clad core board, and forming an etched core board through pattern transfer and etching; performing routing on the copper-embedded area of the etched core board; preparing copper blocks and performing brownification and drying together with the routed core board; using a polyimide film to laminate and press the pretreated core board and copper blocks to form a substrate laminated structure; finally, completing the preparation of the circuit board based on this structure. Through the routing process, it can ensure the accuracy of the copper-embedded area. The brownification treatment enhances the bonding force between copper and the substrate, and the use of the polyimide film for lamination can effectively enhance the stability and mechanical strength of the entire circuit board structure. At the same time, it also provides a buffer for the difference in thermal expansion coefficients between different materials, preventing delamination or fracture problems caused by temperature changes.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board preparation, and more specifically, to a double-sided circuit board with a double-sided copper-embedded symmetric structure and a preparation method thereof. Background Art

[0002] In the electronics manufacturing industry, as the basic structure for carrying and connecting various electronic components, the performance and quality of circuit boards play a crucial role in the reliability of the entire electronic product. With the development of electronic devices towards miniaturization and multi-functionality, for some application scenarios with high power, large current-carrying capacity, and the need for efficient heat dissipation, traditional single-layer or double-layer PCBs (Printed Circuit Boards) are difficult to meet the requirements. To address these issues, the industry has gradually adopted thick copper foils (with a thickness of 2 ounces or more) to manufacture circuit boards to enhance current-carrying capacity and heat dissipation effects.

[0003] However, in practical applications, when the line width does not match the copper thickness or cost considerations do not allow the use of an overall thick copper design, manufacturers usually adopt the method of locally embedding copper blocks / copper bars to resolve this contradiction. This method can provide higher current density and better heat conduction paths in specific areas, while maintaining the fineness of the lines in other parts unchanged, thus achieving a more economical and efficient solution. However, the current conventional processes for embedding copper blocks / copper bars still face many challenges, such as glue overflow, uneven surface leveling, pressure loss, and insufficient bonding strength, which greatly hinder the application of this process. In addition, traditional double-sided circuit boards usually have a thin copper foil covered on both sides, and then the required circuit patterns are formed through processes such as etching. However, with the development of electronic devices towards miniaturization and high performance, traditional double-sided circuit boards are gradually difficult to meet the requirements of some special application scenarios. For example, in cases where good heat dissipation performance or large current-carrying capacity is required, ordinary copper-clad layers and asymmetric circuit patterns may not provide sufficient electrical conductivity or heat conduction ability.

[0004] Therefore, an optimized preparation scheme for a double-sided circuit board with a double-sided copper-embedded symmetric structure is desired. Summary of the Invention

[0005] The present application provides a double-sided circuit board with a double-sided copper-embedded symmetric structure and a preparation method thereof. Through the way of routing processing, the accuracy of the copper-embedded area can be ensured, the brownification treatment enhances the bonding force between copper and the substrate, and the use of polyimide film for lamination treatment can effectively enhance the stability and mechanical strength of the entire circuit board structure. At the same time, it also provides a buffer for the difference in thermal expansion coefficients between different materials, preventing delamination or fracture problems caused by temperature changes.

[0006] In the first aspect, a preparation method for a double-sided circuit board with a double-sided copper-embedded symmetric structure is provided, including:

[0007] Provide a first copper-clad core board and a second copper-clad core board;

[0008] Perform pattern transfer and etching on the first copper-clad core board and the second copper-clad core board to obtain a first etched copper-clad core board and a second etched copper-clad core board;

[0009] Perform routing on the copper-embedded areas of the first etched copper-clad core board and the second etched copper-clad core board to obtain a first routed copper-clad core board and a second routed copper-clad core board;

[0010] Provide copper blocks;

[0011] Perform browning treatment and drying on the first routed copper-clad core board, the second routed copper-clad core board, and the copper blocks to obtain a first pre-treated copper-clad core board, a second pre-treated copper-clad core board, and pre-treated copper blocks;

[0012] Based on a polyimide film, perform lamination on the first pre-treated copper-clad core board, the second pre-treated copper-clad core board, and the pre-treated copper blocks to obtain a circuit board substrate lamination structure;

[0013] Based on the circuit board substrate lamination structure, fabricate a double-sided copper-embedded symmetric structure double-sided circuit board.

[0014] In a second aspect, provided is a double-sided copper-embedded symmetric structure double-sided circuit board, which is fabricated by the method for fabricating a double-sided copper-embedded symmetric structure double-sided circuit board as described in the first aspect.

[0015] A double-sided copper-embedded symmetric structure double-sided circuit board and a method for fabricating the same provided by the present application can ensure the accuracy of the copper-embedded areas through routing treatment, enhance the bonding force between copper and the substrate through browning treatment, and effectively enhance the stability and mechanical strength of the entire circuit board structure by using a polyimide film for lamination treatment. At the same time, it also provides a buffer for the difference in thermal expansion coefficients between different materials, preventing delamination or fracture problems caused by temperature changes. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present application and do not limit the present application.

[0017] Figure 1 It is a schematic flow chart of a double-sided copper-embedded symmetric structure double-sided circuit board and a method for fabricating the same according to an embodiment of the present application.

[0018] Figure 2 It is a schematic flow chart of step S6 in a double-sided copper-embedded symmetric structure double-sided circuit board and a method for fabricating the same according to an embodiment of the present application.

[0019] Figure 3 It is a schematic flowchart of step S2 in the double-sided copper-embedded symmetric structure double-sided circuit board and its manufacturing method according to the embodiment of the present application.

[0020] Figure 4 It is a schematic flowchart of step S24 in the double-sided copper-embedded symmetric structure double-sided circuit board and its manufacturing method according to the embodiment of the present application. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts also belong to the scope of protection of the present application.

[0022] In view of the above technical problems, in the technical solution of the present application, a manufacturing method of a double-sided copper-embedded symmetric structure double-sided circuit board is proposed. As Figure 1 shown, the manufacturing method of the double-sided copper-embedded symmetric structure double-sided circuit board includes: S1, providing a first copper-clad core board and a second copper-clad core board; S2, performing pattern transfer and etching on the first copper-clad core board and the second copper-clad core board to obtain a first etched copper-clad core board and a second etched copper-clad core board; S3, performing routing on the copper-embedded areas of the first etched copper-clad core board and the second etched copper-clad core board to obtain a first routed copper-clad core board and a second routed copper-clad core board; S4, providing copper blocks; S5, performing brownification treatment and drying on the first routed copper-clad core board, the second routed copper-clad core board, and the copper blocks to obtain a first pre-treated copper-clad core board, a second pre-treated copper-clad core board, and pre-treated copper blocks; S6, based on a polyimide film, performing lamination on the first pre-treated copper-clad core board, the second pre-treated copper-clad core board, and the pre-treated copper blocks to obtain a circuit board substrate lamination structure; S7, based on the circuit board substrate lamination structure, manufacturing a double-sided copper-embedded symmetric structure double-sided circuit board. In the above manufacturing method of the double-sided copper-embedded symmetric structure double-sided circuit board, the accuracy of the copper-embedded area can be ensured by routing, the bonding force between copper and the substrate is enhanced by brownification treatment, and the use of a polyimide film for lamination can effectively enhance the stability and mechanical strength of the entire circuit board structure. At the same time, it also provides a buffer for the difference in thermal expansion coefficients between different materials, preventing delamination or fracture problems caused by temperature changes.

[0023] Exemplarily, in step S1, a first copper-clad core board and a second copper-clad core board are provided. That is, first, a suitable copper-clad core board material is selected according to the design specifications. To ensure good electrical performance, mechanical strength, and thermal management capabilities, a substrate with excellent insulation performance and stability, such as FR-4, is usually selected, and copper foils of a certain thickness are covered on both sides. Considering the specific application requirements, for example, in application scenarios with high power or high heat dissipation requirements, thick copper foils (such as 2 ounces or thicker) may be preferentially considered, or additional copper blocks / copper bars may be planned to be locally embedded in certain areas to enhance the current-carrying capacity and heat dissipation efficiency. Two copper-clad core boards are cut out according to precise design dimensions. This process requires the use of high-precision cutting equipment, such as a laser cutting machine or a computer numerical control milling machine (CNC), to ensure that the cut edges are smooth and burr-free, and the dimensional error is controlled within a very small range (such as ±0.05 mm).

[0024] In addition, to facilitate positioning and operation in subsequent processes, clear direction marks and numbers should be marked on each core board for easy tracking and management. After cutting, the newly cut edges are immediately processed to remove any defects that may affect subsequent processes, such as sharp edges or residues. Subsequently, a comprehensive quality inspection of the copper-clad core boards is carried out, focusing on checking the consistency of the copper foil thickness, the surface flatness, and the presence of defects (such as scratches, unevenness, etc.). Only high-quality copper-clad core boards that pass strict screening can continue to the next step - graphic transfer and etching processing.

[0025] Exemplarily, in step S2, the first copper-clad core board and the second copper-clad core board are subjected to graphic transfer and etching processing to obtain a first etched copper-clad core board and a second etched copper-clad core board. That is, on the prepared first copper-clad core board and second copper-clad core board, the pre-designed circuit patterns need to be accurately transferred to the substrate surface. This step is usually completed by using a photomask film or direct imaging technology. Then, a UV exposure machine is used to irradiate these patterns onto the copper-clad core board coated with a photosensitive resist. After exposure, the unexposed part of the resist undergoes a chemical change to form a protective film, while the remaining part remains soluble in the developer. Next, the core board is placed in the developer to remove the resist in the unexposed area, exposing the underlying copper foil. This is the so-called "development" process.

[0026] After development, the crucial etching step follows. At this stage, the core board is immersed in an etching solution with a specific formula, such as strong oxidants like ferric chloride or ammonium persulfate. These chemicals can selectively dissolve the exposed copper layer without affecting the part covered by the resist. To ensure uniform etching effect, the etching time and temperature parameters must be strictly controlled, and at the same time, ensure that the solution is continuously circulated to avoid excessive corrosion caused by local high concentration.

[0027] In addition, a spray etching device can be used to spray the etching solution onto the surface of the core board by means of a high-pressure nozzle. This can not only accelerate the reaction rate but also further improve the etching accuracy. When the etching process is completed, the continuous copper foil that originally covered the entire copper-clad core board has been processed into a complex circuit pattern, forming the first etched copper-clad core board and the second etched copper-clad core board. At this time, the remaining resist needs to be completely removed, usually by means of a cleaning agent or mechanical brushing. The cleaned core board should have no visible resist traces, and the edges of the copper wires should be smooth and neat, without obvious burrs or defects.

[0028] In one embodiment, in the process of performing pattern transfer and etching on the first copper-clad core board and the second copper-clad core board to obtain the first etched copper-clad core board and the second etched copper-clad core board, the size of the routing of the board is 0.05 mm - 0.075 mm larger than that of the copper block.

[0029] Exemplarily, in step S3, the copper-embedded areas of the first etched copper-clad core board and the second etched copper-clad core board are routed to obtain the first routed copper-clad core board and the second routed copper-clad core board. It should be understood that after the pattern transfer and etching processes are completed, the two copper-clad core boards have formed the required circuit patterns. At this time, for the positions where the copper blocks need to be embedded, part of the substrate must be precisely removed to reserve a suitable space for the copper blocks. To achieve this, it is very necessary to use the routing (also known as milling or hollowing) technology. The routing equipment can be a computer numerical control (CNC) milling machine, which can automatically perform high-precision cutting tasks according to a preset program, ensuring that the size and shape of each copper-embedded area strictly meet the design requirements. In actual operation, technicians will fix the etched copper-clad core board on a stable platform to ensure that it does not shift during the entire processing process.

[0030] Then, use a special fixture to firmly fix the core board to prevent machining deviation caused by vibration or other external factors. Next, generate the routing paths through computer-aided design (CAD) software and import them into the CNC milling machine. These paths precisely indicate the specific locations, depths, and edge contours where material needs to be removed, ensuring that each copper-embedded area can perfectly match the copper blocks to be embedded. During the routing process, it is necessary to pay attention to maintaining appropriate cutting speeds and feed rates, which helps reduce heat generation and avoid material deformation. At the same time, to avoid dust and other impurities from contaminating the working area, an effective dust extraction system should be equipped to promptly clean up the generated debris. In addition, to ensure that the edges of the copper-embedded areas are smooth and neat, a grinding wheel or grinding head is usually used for slight polishing after the routing is completed to remove any possible burrs or unevenness. This additional treatment not only improves the operational convenience when embedding the copper blocks subsequently but also enhances the contact area between the two, thereby improving the bonding strength. When the routing process is completed, the copper-embedded areas on each copper-clad core board are ready for the next steps of brownification treatment and drying. It is worth noting that to ensure consistency between the two copper-clad core boards, the routing operations should be carried out as synchronously as possible or at least completed under the same conditions. This can minimize the impact of any minor differences and ensure that the final double-sided copper-embedded symmetric structure has a high degree of balance and stability.

[0031] Exemplarily, in step S4, copper blocks are provided. That is, appropriate copper materials are selected according to the design requirements. For application scenarios that require high electrical conductivity and good heat conduction characteristics, electrolytic copper with a relatively high purity (such as C1020 or C1100) is usually selected because such materials have excellent electrical properties and machining properties. In addition, considering the cost-benefit ratio and the coefficient of thermal expansion matching with insulating substrates such as FR-4, nickel plating or other surface treatment methods are sometimes used to enhance the corrosion resistance and bonding strength of the copper blocks. To meet the requirements of different sizes and shapes, the copper blocks can be solid blocks, bars, or other customized forms.

[0032] Next, after determining the material of the copper blocks, they need to be cut. This step is crucial because it directly affects whether the copper blocks can be smoothly embedded into the pre-prepared copper-clad core board. To ensure accuracy, a CNC milling machine, laser cutting machine, or stamping equipment is usually used for cutting. Regardless of which method is used, the operation must be carried out strictly according to the dimensions specified in the design drawings to ensure that the outer contour, thickness, and edge treatment of each copper block meet the standards. For example, the unilateral dimension should be 0.05 mm to 0.075 mm larger than the routed space to facilitate placement without causing excessive gaps. In addition, to prevent the heat generated during the cutting process from affecting the quality of the copper blocks, it is recommended to use coolant-assisted machining and regularly check the tool status to avoid dimensional deviations caused by tool wear.

[0033] Exemplarily, in step S5, the first copper-clad core board after routing, the second copper-clad core board after routing, and the copper block are subjected to brownification treatment and dried to obtain the first pre-treated copper-clad core board, the second pre-treated copper-clad core board, and the pre-treated copper block. It should be understood that after the routing process is completed, that is, an accurate space has been reserved for the copper block, and then these components need to be subjected to brownification treatment. Brownification is a chemical treatment method that forms a uniform and stable oxide film on the copper surface through a specific chemical solution. This oxide film has good hydrophilicity and high activity, which can significantly improve the bonding force between the copper and the semi-cured sheet resin, thus ensuring that there will be no delamination or debonding during the lamination process. In addition, the brownification treatment can also play a certain anti-corrosion role to protect the copper material from environmental factors.

[0034] To ensure the consistency and reliability of the brownification effect, the entire treatment process needs to be carried out under strict control conditions. First, the technical personnel will put the copper-clad core board after routing and the cut copper block into a specially designed brownification tank. The brownification tank is filled with a pre-prepared brownification solution, usually composed of sulfuric acid, hydrogen peroxide, and other additives. These components act together on the copper surface to promote the formation of the required oxide film. The treatment time is generally set from a few minutes to more than ten minutes, depending on the formula of the brownification solution used and the thickness of the required oxide film. During the whole process, the temperature of the brownification solution must be kept stable to avoid poor treatment effects caused by temperature fluctuations.

[0035] After the brownification treatment is completed, all components are immediately dried. The purpose of drying is to completely remove the residual moisture during the brownification process to prevent possible bubbles or other quality problems in the subsequent processes. For this purpose, a special oven or infrared drying equipment can be used for rapid and uniform heating. The drying temperature is usually set between 80°C and 120°C, and the duration is from dozens of minutes to several hours. The specific parameters should be adjusted according to the actual materials used and the characteristics of the brownification solution. During this period, the status of the components also needs to be checked regularly to ensure that no abnormal situations such as deformation or discoloration occur. When the drying process is completed, the pre-treated first copper-clad core board, the second copper-clad core board, and the copper block are obtained. At this time, their surfaces are covered with a uniform brownification film, which not only increases the bonding force with the semi-cured sheet resin but also has good corrosion resistance.

[0036] In one embodiment, as Figure 2As shown, in step S6, based on the polyimide film, the first pretreated copper clad core board, the second pretreated copper clad core board and the pretreated copper block are laminated to obtain a circuit board substrate laminate structure, including: S61, attaching a first polyimide film on the copper foil of the first pretreated copper clad core board; S62, placing the pretreated copper block on the first polyimide film, wherein the pretreated copper block corresponds to the copper embedded area of ​​the first pretreated copper clad core board; S63, placing a predetermined number of prepregs on the pretreated copper block based on thickness requirements; S64, placing the second pretreated copper clad core board on the prepreg; S65, placing the pretreated copper block on the second pretreated copper clad core board; S66, placing a second polyimide film on the pretreated copper block to obtain a laminate structure; S67, pressing the laminate structure to obtain the circuit board substrate laminate structure.

[0037] In one embodiment, the thickness of the first polyimide film and the second polyimide film is 0.025 mm-0.05 mm.

[0038] It should be understood that before preparing for lamination, it is necessary to ensure that all components - including two pre-treated copper clad core boards and cut copper blocks - have been browned and dried, and a uniform and stable oxide film has been formed on the surface. These oxide films enhance the adhesion between copper and subsequent materials, while also providing good corrosion protection. Next, technicians will attach a polyimide film (PI film) with a thickness of 0.025mm to 0.05mm to the outer copper foil of the first pre-treated copper clad core board (L1 / L2). As a high-performance insulating material, PI film has excellent mechanical strength, thermal stability and electrical properties. It can effectively isolate different conductive layers and maintain its shape without deformation under high temperature and high pressure environments.

[0039] After the PI film is attached, the next step is to accurately place the pre-treated copper block on it. This step requires extremely high precision because the copper block must completely correspond to the hollow area and be in close contact with the surrounding substrate. In order to ensure the correct placement, a high-precision positioning device or a visual recognition system is usually used to assist the operation. When the copper block is in place, a predetermined number of prepregs are laid on top of the copper block according to design requirements. Generally, 2116 prepregs with a glue content of 55%-58% are selected. These prepregs have the function of filling gaps and leveling surfaces. At the same time, the resin components in them will flow and solidify during the subsequent lamination process to form a solid connection.

[0040] Subsequently, turn the second pre-treated copper-clad core board (L3 / L4) over so that its L4 side faces upward, and also attach a PI film on its outer side. Then, repeat the above steps, place another pre-treated copper block on this copper-clad core board, and continue to add the required prepreg. The purpose of doing this is to ensure that the copper-embedded structures on the upper and lower sides are symmetrically consistent, thereby improving the balance and stability of the entire circuit board. Finally, attach another PI film on the top layer to enclose the entire laminated structure.

[0041] At this point, all the materials have been accurately stacked together according to the design requirements, forming a complete laminated structure of the circuit board substrate. However, to make this structure truly stable and reliable, a crucial operation - pressing - is still needed. Pressing is carried out under high temperature and high pressure conditions. Through a dedicated device, uniform pressure and heat are applied, enabling the layers of materials to be tightly bonded. In particular, the resin in the prepreg fully penetrates between each interface and finally cures to form irreversible chemical bonds. The pressing parameters such as temperature, pressure, and time need to be strictly controlled to ensure the best results. In addition, target holes need to be drilled before pressing to facilitate precise positioning in subsequent processes.

[0042] Exemplarily, in step S7, based on the laminated structure of the circuit board substrate, a double-sided copper-embedded symmetric structure double-sided circuit board is prepared. It should be understood that when all the materials - including two pre-treated copper-clad core boards (L1 / L2 and L3 / L4), polyimide films (PI films), and pre-treated copper blocks - have been accurately stacked together according to the design requirements and formed a complete laminated structure of the circuit board substrate, the next crucial stage is pressing. Pressing is carried out under high temperature and high pressure conditions with the aim of tightly bonding the layers of materials. In particular, the resin in the prepreg fully penetrates between each interface and finally cures to form irreversible chemical bonds. To ensure the best results, technicians will place the laminated structure into a special hot press and set appropriate temperature, pressure, and time parameters. For example, the temperature is usually set between 170°C and 180°C, the pressure is about 2 to 3 MPa, and the duration is 60 to 90 minutes. These parameters need to be fine-tuned according to the specific materials used and the characteristics of the equipment to ensure the pressing quality.

[0043] After pressing is completed, the circuit board substrate taken out from the hot press also needs to go through some necessary post-treatment processes. First, the PI films on the two outer surfaces are torn off because these films are only used for protection and isolation and are no longer needed after pressing. If there is excess glue at the interface between the edge of the copper block and the core board routing cavity, a double-sided sanding belt grinding plate needs to be used for grinding to remove the excess resin residues and ensure the surface is flat and smooth. In addition, for some application scenarios, it may also be necessary to perform additional grinding or polishing on the area around the copper block to improve the appearance quality and contact performance.

[0044] Next, enter the drilling process. Using high-precision equipment such as CNC drills or laser drilling machines, the required through-holes and blind holes are drilled at the specified positions according to the design drawings. These holes are not only used for installing electronic components but also provide channels for subsequent electroplating and other processes. During the drilling process, strict dimensional control and positioning accuracy must be maintained to avoid short circuits or other failures caused by deviations. After drilling, a copper deposition treatment is also required, that is, a thin and uniform copper film is deposited on the hole wall to ensure good electrical connection.

[0045] Subsequently, full-panel electroplating is carried out. This step is to form a thick and uniform copper layer on the entire circuit board surface, thereby enhancing conductivity and corrosion resistance. During the electroplating process, technicians will closely monitor parameters such as current density, solution composition, and temperature to ensure that the coating quality meets the standards. Immediately following is the graphic transfer and copper-tin plating process, that is, using a resist to cover the parts that do not need to be electroplated, and then thickening the copper layer on the exposed copper surface through the electroplating process, and finally plating a layer of tin as a protective coating. The resist stripping, etching, and tin stripping processes are to remove the resist and etch away the excess parts, leaving the final circuit pattern.

[0046] Among them, the double-sided copper-embedded symmetric structure double-sided circuit board has the following advantages: First, the copper block and the FR4 routing vacancy have a small clearance fit, which is convenient for placing and taking the copper block. At the same time, it can ensure that the resin of the prepreg is filled around the four sides of the copper block, plus the full contact of the resin of the bottom prepreg, which is beneficial to improving the bonding strength between the two materials. Second, the blanking of the copper block is equivalent to that of the two core boards. Taking the two outer surface steel plates as the reference surfaces, 2-3 prepregs are used in the middle during lamination. When the copper block is slightly thinner or thicker than the core board, the prepregs in the middle have enough buffer space to ensure that the surface of the copper block is completely flush with the surfaces of the first and second core boards. Third, a 0.025 - 0.05 MM PI film is pasted on the two outer surfaces, which can ensure that the resin of the prepreg fills along the gaps between the core board and the copper block during lamination without contaminating the surface copper foils of the first and second core boards. Even if there is any contamination, it is very little and can be easily removed by normal sanding with a sanding belt once. Fourth, using a copper-core board will not cause quality problems caused by wrinkles in the conventional lamination of thin copper foils. Fifth, the symmetric structure is beneficial to the control of board warping. At the same time, it can ensure that copper can be embedded at the same position on the upper and lower surfaces for current carrying and heat dissipation of different electrical networks, with less limitation on design.

[0047] In particular, for a double-sided copper-inlaid symmetric structure double-sided circuit board, ensuring the consistency of the circuit patterns on both sides is crucial, because the high matching of the circuits on both sides can ensure the consistency of the current path and the synchronous transmission of signals. If there are deviations in the patterns on both sides, it may lead to impedance mismatch, which in turn affects the signal quality and electrical performance. Specifically, the inconsistency of the circuit patterns may result in different current paths, causing changes in electrical parameters such as resistance, capacitance, and inductance. This will affect the operating frequency, signal integrity, and power efficiency of the circuit. Especially in high-speed digital circuits and high-frequency analog circuits, any slight change may lead to a decline in product performance or functional failure. For high-power applications, good heat dissipation is the key to ensuring the stable operation of the device. If the circuit designs on both sides are asymmetric, it may affect the uniform distribution of heat, resulting in excessive temperature in some areas, which in turn affects the lifespan of electronic components or even causes damage. In addition, the asymmetric design may also limit the effective heat dissipation path, making the overall heat dissipation effect worse.

[0048] Based on this, in the process of pattern transfer and etching treatment of the first copper-clad core board and the second copper-clad core board, it is crucial to evaluate the consistency between the transferred pattern of the first etched copper-clad core board and the transferred pattern of the second etched copper-clad core board to determine the pattern transfer quality. Specifically, in the process of pattern transfer quality evaluation, the technical concept of this application is to collect the transferred pattern images of the first etched copper-clad core board and the second etched copper-clad core board through a camera, and introduce image processing and analysis algorithms based on artificial intelligence and machine vision at the backend to analyze the transferred pattern images of the first etched copper-clad core board and the second etched copper-clad core board, so as to extract the semantic features in the two transferred pattern images, and perform pattern transfer quality evaluation based on the joint perception contrast feature representation between the semantics of the two transferred pattern images of the etched copper-clad core boards, thereby judging whether the consistency between the transferred pattern of the first etched copper-clad core board and the transferred pattern of the second etched copper-clad core board meets the preset standard. In this way, it is possible to automatically evaluate the pattern transfer quality based on the joint analysis results of the semantics of the two transferred patterns of the etched copper-clad core boards, so as to take corresponding measures in time when the detected quality does not meet the preset standard. Through this intelligent processing method, it is helpful to ensure the electrical performance and heat dissipation effect of the final double-sided copper-inlaid symmetric structure double-sided circuit board product.

[0049] In one embodiment, as Figure 3As shown, performing pattern transfer and etching processes on the first copper-clad core board and the second copper-clad core board to obtain a first etched copper-clad core board and a second etched copper-clad core board includes: S21, collecting a transferred pattern image of the first etched copper-clad core board and a transferred pattern image of the second etched copper-clad core board through a camera; S22, performing image noise reduction and image enhancement on the transferred pattern image of the first etched copper-clad core board and the transferred pattern image of the second etched copper-clad core board to obtain a first pre-processed transferred pattern image and a second pre-processed transferred pattern image; S23, respectively performing transferred pattern image feature extraction on the first pre-processed transferred pattern image and the second pre-processed transferred pattern image to obtain a first transferred pattern image semantic coding feature and a second transferred pattern image semantic coding feature; S24, performing feature joint perception based on a semantic information field on the first transferred pattern image semantic coding feature and the second transferred pattern image semantic coding feature to obtain a first-second transferred pattern image semantic coding comparison feature; S25, based on the first-second transferred pattern image semantic coding comparison feature, determining whether the consistency between the transferred pattern of the first etched copper-clad core board and the transferred pattern of the second etched copper-clad core board meets a preset standard.

[0050] Exemplarily, in step S21, a transferred pattern image of the first etched copper-clad core board and a transferred pattern image of the second etched copper-clad core board are collected through a camera. It should be possible that collecting the transferred pattern image of the first etched copper-clad core board and the transferred pattern image of the second etched copper-clad core board is to ensure a high degree of matching of the circuit patterns on both sides of the double-sided copper-inlaid symmetric structure double-sided circuit board, which is crucial for ensuring the consistency of the current path and signal synchronous transmission. If there are deviations in the patterns on both sides, it may lead to impedance mismatch, thereby affecting signal quality and electrical performance. Especially in high-speed digital circuits and high-frequency analog circuits, any subtle change may cause a decline in product performance or functional failure. In addition, good heat dissipation design depends on a symmetric structure to ensure uniform heat distribution and avoid local overheating problems.

[0051] In one embodiment, first, it is necessary to ensure that the camera is installed in a fixed and stable position to avoid shooting deviations caused by vibration or other external interferences. Use a high-resolution industrial camera and equip it with an appropriate lens and light source system to obtain clear and high-contrast images. Calibrate the camera, including focal length adjustment, white balance setting, etc., to ensure consistent results for each shot. Place the first etched copper-clad core board and the second etched copper-clad core board on a dedicated platform respectively, and this platform has precise positioning devices, such as vacuum adsorption or mechanical jigs, to ensure that each core board remains stationary during the shooting process.

[0052] Exemplarily, in step S22, image denoising and image enhancement are performed on the transferred pattern image of the first etched copper-clad core board and the transferred pattern image of the second etched copper-clad core board to obtain a first preprocessed transferred pattern image and a second preprocessed transferred pattern image. It should be understood that in an actual production environment, due to various factors such as lighting conditions, shooting angles, surface reflections, etc., the original images collected often contain noise and other interferences, which will affect the accuracy of subsequent processing. Image denoising can remove or reduce these unnecessary components, while image enhancement can highlight important structural information, making the circuit lines more clearly visible, thus providing a more reliable basis for subsequent feature extraction and quality assessment.

[0053] Specifically, in the preparation process of a double-sided copper-embedded symmetric structure double-sided circuit board, the circuit patterns on the two copper-clad core boards need to be highly matched to ensure the consistency of the current path and the synchronous transmission of signals. If there are deviations in the patterns on both sides, it may lead to impedance mismatch, thereby affecting signal quality and electrical performance. Therefore, it is necessary to ensure that the images used for evaluation have high resolution, good contrast, and accurate color representation. Image denoising and enhancement processing are precisely for this purpose, which helps to improve the accuracy of pattern consistency evaluation and ensure the quality of the circuit board.

[0054] In one embodiment, for image denoising, the present application selects a denoising algorithm based on wavelet transform. This algorithm can effectively remove random noise while retaining edge details, making the image smoother and cleaner. Next is the image enhancement step, where the method of histogram equalization is adopted. It adjusts the distribution of the image gray values, expands the brightness range, enhances the contrast, and makes the originally darker or brighter parts more obvious. In addition, an adaptive contrast adjustment technique is also applied, which dynamically changes the contrast according to the characteristics of the local area, further highlighting small but important structural features such as pad centers and line endpoints. After the above processing, a first preprocessed transferred pattern image and a second preprocessed transferred pattern image are obtained. At this time, the circuit lines in the image are already very clear, the background noise has almost completely disappeared, and each key feature point is also easier to identify.

[0055] Exemplarily, in step S23, the first pre-processed transfer pattern image and the second pre-processed transfer pattern image are respectively subjected to transfer pattern image feature extraction to obtain a first transfer pattern image semantic encoding feature and a second transfer pattern image semantic encoding feature. It should be understood that considering that the patterns on the circuit board are usually very complex and contain a large amount of circuit detail information. Although traditional CNNs can capture local features well, they are limited in dealing with global circuit semantics and context relationships. At the same time, automated inspection systems in the electronics manufacturing industry often need to process a large amount of data in real time, so there are high requirements for the speed and efficiency of the algorithm. Based on this, in the technical solution of this application, the first pre-processed transfer pattern image and the second pre-processed transfer pattern image are further respectively input into a transfer pattern image feature extractor based on the Mobile-Former model to obtain a first transfer pattern image semantic encoding feature map and a second transfer pattern image semantic encoding feature map. It should be understood that the Mobile-Former model is a hybrid deep learning model that combines the advantages of the Transformer architecture and lightweight convolutional neural networks (CNNs). It aims to solve the limitations of traditional CNNs in dealing with long-range dependencies and also overcomes the problem of high computational resource consumption of pure Transformer models, enabling the model to operate efficiently in resource-constrained environments. Therefore, through the processing of the transfer pattern image feature extractor based on the Mobile-Former model, on the basis of respectively capturing the local features in the first pre-processed transfer pattern image and the second pre-processed transfer pattern image, it can further perceive the global context-local association semantic feature information, so as to better understand and encode these complex pattern structures and their associations, thereby generating more accurate semantic encoding feature maps.

[0056] In one embodiment, respectively subjecting the first pre-processed transfer pattern image and the second pre-processed transfer pattern image to transfer pattern image feature extraction to obtain a first transfer pattern image semantic encoding feature and a second transfer pattern image semantic encoding feature includes: respectively inputting the first pre-processed transfer pattern image and the second pre-processed transfer pattern image into a transfer pattern image feature extractor based on the Mobile-Former model to obtain a first transfer pattern image semantic encoding feature map as the first transfer pattern image semantic encoding feature and a second transfer pattern image semantic encoding feature map as the second transfer pattern image semantic encoding feature.

[0057] Exemplarily, in step S24, the semantic coding features of the first transfer pattern image and the semantic coding features of the second transfer pattern image are subjected to feature joint perception based on the semantic information field to obtain the first-second transfer pattern image semantic coding contrast features. It should be understood that since the semantic coding feature map of the first transfer pattern image and the semantic coding feature map of the second transfer pattern image respectively contain the semantic feature information of the transfer pattern image of the first copper-clad core board after etching and the semantic feature information of the transfer pattern image of the second copper-clad core board after etching. In order to be able to perform interactive analysis and contrast difference feature perception on the semantics of these two transfer pattern images and provide a basis for subsequent pattern transfer consistency quality evaluation of the two, in the technical solution of the present application, the semantic coding features of the first transfer pattern image and the semantic coding features of the second transfer pattern image are further subjected to feature joint perception based on the semantic information field to obtain the first-second transfer pattern image semantic coding contrast features. In particular, through the feature joint perception processing based on the semantic information field, the semantic information field can be used as a guide to realize the interaction and modulation between features, thereby generating a richer and semantically interpretable first-second transfer pattern image semantic coding contrast feature representation. In this way, the subtle differences between the patterns on both sides of the circuit board can be captured more accurately. This helps to improve the accuracy of the consistency evaluation and ensure the quality of the circuit board.

[0058] In one embodiment, as Figure 4 shown, subjecting the semantic coding features of the first transfer pattern image and the semantic coding features of the second transfer pattern image to feature joint perception based on the semantic information field to obtain the first-second transfer pattern image semantic coding contrast features includes: S241, connecting the semantic coding feature map of the second transfer pattern image and the semantic coding feature map of the first transfer pattern image and inputting them into a semantic information field predictor based on gated convolution to obtain a transfer pattern image semantic information field; S242, based on the transfer pattern image semantic information field, performing feature joint perception on the semantic coding feature map of the second transfer pattern image and the semantic coding feature map of the first transfer pattern image to obtain a first-second transfer pattern image semantic coding contrast feature map as the first-second transfer pattern image semantic coding contrast feature.

[0059] Exemplarily, in step S241, connecting the semantic coding feature map of the second transfer pattern image and the semantic coding feature map of the first transfer pattern image and inputting them into a semantic information field predictor based on gated convolution to obtain a transfer pattern image semantic information field, specifically, this process can be expressed by the formula:

[0060]

[0061] where is the semantic encoding feature map of the second transfer pattern image, is the semantic encoding feature map of the first transfer pattern image, represents a feature connection operation, is a convolutional layer with a convolutional kernel of ; is point convolution processing, is the semantic information field of the transfer pattern image.

[0062] It should be understood that performing feature connection on the semantic encoding feature map of the second transfer pattern image and the semantic encoding feature map of the first transfer pattern image means combining them into a new multi-channel feature representation, which fuses information from two directions. This is done to enable the model to consider the content of both pictures simultaneously and learn the correspondence between them. Subsequently, this combined feature is fed into a semantic information field predictor based on gated convolution. Gated convolution is a special convolutional operation that allows the network to dynamically adjust the size of its receptive field according to the input data, which means it can capture long-range dependencies more flexibly, especially important when dealing with complex circuit patterns. In addition, the gating mechanism can also help the model focus on the regions that are truly important for the task, suppress the unimportant parts, and improve computational efficiency. The task of the semantic information field predictor is to generate the so-called "semantic information field of the transfer pattern image" using the above input. Simply put, this is a global mapping that describes the semantic similarity and difference between two transfer patterns. In this mapping, each position represents the degree of semantic feature matching of two patterns in a specific local area. Ideally, if the patterns on two copper-clad core boards are exactly the same, then a highly consistent distribution pattern should be presented throughout the semantic information field; conversely, if there are any deviations or asymmetries, obvious outliers will be shown at the corresponding positions. This method based on the semantic information field has significant advantages compared to traditional pixel-level comparison. Because traditional methods often only stay at the surface morphological comparison, are easily affected by factors such as noise and lighting changes, and are powerless for deep functional differences. By constructing the semantic information field, this application can not only more accurately identify where changes have occurred, but also understand the meaning behind these changes. For example, in an actual production environment, even if two patterns look very similar, but if they have different connection methods or wiring strategies at key nodes, this may lead to a huge gap in the performance of the final product.

[0063] In one embodiment, in step S242, based on the semantic information field of the transfer pattern image, feature joint perception is performed on the second transfer pattern image semantic encoding feature map and the first transfer pattern image semantic encoding feature map to obtain the first-second transfer pattern image semantic encoding contrast feature map as the first-second transfer pattern image semantic encoding contrast feature, including: mapping the second transfer pattern image semantic encoding feature map to the transfer pattern image semantic information field to obtain the field-modulated second transfer pattern image semantic encoding feature map. Specifically, this process can be expressed by the formula:

[0064]

[0065] where, is element-wise multiplication by position, is the field-modulated second transfer pattern image semantic encoding feature map.

[0066] Input the first transfer pattern image semantic encoding feature map and the field-modulated second transfer pattern image semantic encoding feature map into a feature joint perception module based on a multiple attention structure to obtain the first-second transfer pattern image semantic encoding contrast feature map. Specifically, this process can be expressed by the formula:

[0067]

[0068]

[0069]

[0070] where, is pointwise convolution processing, is global average pooling operation, is per-channel convolution processing, is a batch normalization layer, is the Sigmoid function, is the second transfer pattern image semantic attention optimized expression feature map, is the attention-optimized first transfer pattern image semantic attention optimized expression feature map, is addition by position, is the first-second transfer pattern image semantic encoding contrast feature map.

[0071] It should be understood that in the process of mapping the semantic encoded feature map of the second transfer pattern image to the field modulation, in fact, the previously generated semantic information field is used as a guide to adjust or enhance the semantic encoding features of the second transfer pattern image. This process can be regarded as adding a layer of weights or emphasis marks to the original semantic encoded feature map, making the areas identified as important in the semantic information field more prominent, while the non-critical parts are appropriately weakened. Such an operation improves the sensitivity of the model to specific objects or regions, enabling it to better adapt to various complex situations in actual production. For example, even slight changes in certain key nodes such as power lines and signal lines may affect the function of the entire circuit, while differences in other non-critical regions will not significantly affect the overall performance. The new feature map obtained through field modulation - that is, the field modulation second transfer pattern image semantic encoded feature map - is an optimized expression of the original second transfer pattern image semantic encoded feature map, retaining both the original local detail information and enhancing the attention to key regions through the adjustment of the semantic information field. This step provides a more reliable basis for subsequent quality assessment. Finally, the optimized field modulation second transfer pattern image semantic encoded feature map and the first transfer pattern image semantic encoding feature Figure 1 are jointly input into the feature joint perception module based on the multi-attention structure. The role of this module is to further analyze the correlation and contrast characteristics between the two. Through the multi-attention mechanism, the model can focus on the regions and features that are most critical for determining pattern consistency and electrical performance. The multi-attention structure allows the model to consider multiple different levels of information simultaneously and establish connections between these information, thereby more accurately identifying the subtle differences between the two transfer pattern images.

[0072] In summary, through the feature joint perception processing based on the semantic information field, by constructing the semantic information field and modulating the semantic features of the second transfer pattern image accordingly, it is ensured that the feature expression not only contains rich detail information but also is consistent with the structure of the semantic features of the first transfer pattern image. Specifically, in the actual process of pattern transfer quality assessment, there may be some asymmetries or variations in the patterns on the circuit board (such as line width differences, shape distortions, etc.). In such cases, semantic-level feature modulation helps to improve the sensitivity of the model to specific objects or regions, thus better adapting to these complex situations. In this way, it can more effectively help to identify the feature differences between the two transfer pattern images to generate the first-second transfer pattern image semantic encoding contrast feature, which is used to subsequently determine whether the consistency between the transfer pattern of the first etched copper-clad core board and the transfer pattern of the second etched copper-clad core board meets the preset standard, thereby ensuring the consistency of the double-sided circuit board pattern.

[0073] Exemplarily, in step S25, based on the first-second transfer pattern image semantic coding contrast feature, it is determined whether the consistency between the transfer pattern of the first etched copper-clad core board and the transfer pattern of the second etched copper-clad core board meets a preset standard. In one embodiment, based on the first-second transfer pattern image semantic coding contrast feature, determining whether the consistency between the transfer pattern of the first etched copper-clad core board and the transfer pattern of the second etched copper-clad core board meets a preset standard includes: inputting the first-second transfer pattern image semantic coding contrast feature map into a pattern transfer quality evaluator based on a classifier to obtain an evaluation result, and the evaluation result is used to represent whether the consistency between the transfer pattern of the first etched copper-clad core board and the transfer pattern of the second etched copper-clad core board meets a preset standard. That is to say, classification processing is performed using the joint perceptual semantic contrast representation between the transfer pattern image semantic feature of the first etched copper-clad core board and the transfer pattern image semantic feature of the second etched copper-clad core board, so as to perform pattern transfer quality evaluation, thereby determining whether the consistency between the transfer pattern of the first etched copper-clad core board and the transfer pattern of the second etched copper-clad core board meets a preset standard. In this way, the pattern transfer quality can be automatically evaluated based on the semantic joint analysis result of the transfer patterns of these two etched copper-clad core boards, so as to take corresponding measures in time when it is detected that the quality does not meet the preset standard. Through this intelligent processing method, it is helpful to ensure the electrical performance and heat dissipation effect of the final double-sided copper-embedded symmetric structure double-sided circuit board product.

[0074] In summary, the double-sided copper-embedded symmetric structure double-sided circuit board and its manufacturing method according to the embodiments of the present application are elucidated. Through the way of routing processing, the accuracy of the copper-embedded area can be ensured, the brownification treatment enhances the bonding force between copper and the substrate, and the use of polyimide film for lamination treatment can effectively enhance the stability and mechanical strength of the entire circuit board structure. At the same time, it also provides a buffer for the difference in thermal expansion coefficients between different materials, preventing delamination or fracture problems caused by temperature changes.

[0075] Specifically, a double-sided copper-embedded symmetric structure double-sided circuit board is also provided, and the double-sided copper-embedded symmetric structure double-sided circuit board is manufactured by the manufacturing method of the double-sided copper-embedded symmetric structure double-sided circuit board described above.

[0076] The basic principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present invention are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present invention. In addition, the specific details of the above embodiments are only for the purposes of illustration and easy understanding, rather than limitations. The above details do not limit the present invention to necessarily adopt the above specific details to implement.

[0077] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments. In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the module division is only a logical function division, and there may be other division methods in actual implementation. The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0078] In addition, in each embodiment of the present invention, the functional modules can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware, or in the form of a combination of hardware and software functional modules.

[0079] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to cover all changes within the meaning and scope of the equivalent elements of the claims in the present invention. Any associated drawing marks in the claims should not be regarded as limiting the claims involved.

[0080] In addition, obviously, the term "including" does not exclude other units or steps, and the singular does not exclude the plural. The multiple units stated in the device claims can also be implemented by one unit through software or hardware.

[0081] Finally, it should be noted that the above description has been given for the purposes of illustration and description. In addition, the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure, characterized in that: include: Providing a first copper clad core board and a second copper clad core board; Performing pattern transfer and etching treatment on the first copper clad core board and the second copper clad core board to obtain a first etched copper clad core board and a second etched copper clad core board; Performing lamination treatment on the copper embedded areas of the first etched copper clad core board and the second etched copper clad core board to obtain a first lamination copper clad core board and a second lamination copper clad core board; Provide copper blocks; The first copper clad core board after the gong plate, the second copper clad core board after the gong plate and the copper block are subjected to browning treatment and drying to obtain a first pre-treated copper clad core board, a second pre-treated copper clad core board and a pre-treated copper block; Based on the polyimide film, the first pretreated copper clad core board, the second pretreated copper clad core board and the pretreated copper block are laminated to obtain a circuit board substrate laminated structure; Based on the circuit board substrate laminated structure, a double-sided circuit board with a double-sided copper embedded symmetrical structure is prepared; The first copper clad core board and the second copper clad core board are subjected to pattern transfer and etching to obtain a first etched copper clad core board and a second etched copper clad core board, comprising: Collecting a transfer pattern image of the first etched copper clad core board and a transfer pattern image of the second etched copper clad core board through a camera; Performing image noise reduction and image enhancement on the first etched copper clad core board transfer pattern image and the second etched copper clad core board transfer pattern image to obtain a first pre-processed transfer pattern image and a second pre-processed transfer pattern image; Performing transfer pattern image feature extraction on the first preprocessed transfer pattern image and the second preprocessed transfer pattern image to obtain a first transfer pattern image semantic coding feature and a second transfer pattern image semantic coding feature; Performing feature joint perception based on the semantic information field on the first transfer pattern image semantic coding feature and the second transfer pattern image semantic coding feature to obtain a first-second transfer pattern image semantic coding contrast feature; Based on the semantic coding comparison features of the first-second transfer pattern images, determining whether the consistency between the transfer pattern of the first etched copper clad core board and the transfer pattern of the second etched copper clad core board meets a preset standard; The method of performing feature joint perception based on the semantic information field on the semantic coding features of the first transfer pattern image and the semantic coding features of the second transfer pattern image to obtain the first-second transfer pattern image semantic coding contrast features includes: The second transfer pattern image semantic encoding feature map and the first transfer pattern image semantic encoding feature map are feature-connected and then input into a semantic information field predictor based on gated convolution to obtain a transfer pattern image semantic information field; Based on the transfer pattern image semantic information field, feature joint perception is performed on the second transfer pattern image semantic coding feature map and the first transfer pattern image semantic coding feature map to obtain a first-second transfer pattern image semantic coding contrast feature map as the first-second transfer pattern image semantic coding contrast feature.

2. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 1, characterized in that: In performing pattern transfer and etching on the first copper clad core board and the second copper clad core board to obtain a first etched copper clad core board and a second etched copper clad core board, the size of the gong plate is 0.05 mm-0.075 mm larger than the copper block.

3. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 2, characterized in that: Based on the polyimide film, the first pretreated copper clad core board, the second pretreated copper clad core board and the pretreated copper block are laminated to obtain a circuit board substrate laminate structure, including: Attaching a first polyimide film to the copper foil of the copper clad core board after the first pretreatment; Placing the pretreated copper block on the first polyimide film, wherein the pretreated copper block corresponds to the copper embedded area of ​​the first pretreated copper clad core board; Based on thickness requirements, placing a predetermined number of prepregs on the pretreated copper block; Placing the second pretreated copper clad core board on the prepreg; Placing the pretreated copper block on the second pretreated copper clad core board; placing a second polyimide film on the pretreated copper block to obtain a laminated structure; The laminated structure is pressed to obtain the circuit board substrate laminated structure.

4. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 3, characterized in that: The thickness of the first polyimide film and the second polyimide film is 0.025 mm-0.05 mm.

5. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 4, characterized in that: Transfer pattern image feature extraction is performed on the first preprocessed transfer pattern image and the second preprocessed transfer pattern image respectively to obtain a first transfer pattern image semantic coding feature and a second transfer pattern image semantic coding feature, including: inputting the first preprocessed transfer pattern image and the second preprocessed transfer pattern image respectively into a transfer pattern image feature extractor based on a Mobile-Former model to obtain a first transfer pattern image semantic coding feature map as the first transfer pattern image semantic coding feature and a second transfer pattern image semantic coding feature map as the second transfer pattern image semantic coding feature.

6. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 5, characterized in that: Based on the transfer pattern image semantic information field, performing feature joint perception on the second transfer pattern image semantic coding feature map and the first transfer pattern image semantic coding feature map to obtain a first-second transfer pattern image semantic coding contrast feature map as the first-second transfer pattern image semantic coding contrast feature, including: Mapping the second transfer pattern image semantic coding feature map to the transfer pattern image semantic information field to obtain a field-domain modulated second transfer pattern image semantic coding feature map; The first transfer pattern image semantic coding feature map and the field modulated second transfer pattern image semantic coding feature map are input into a feature joint perception module based on a multiple attention structure to obtain the first-second transfer pattern image semantic coding contrast feature map.

7. The method for preparing a double-sided circuit board with a double-sided copper embedded symmetrical structure according to claim 6, characterized in that: Based on the semantic coding contrast features of the first-second transfer pattern images, determining whether the consistency between the transfer pattern of the first etched copper clad core board and the transfer pattern of the second etched copper clad core board meets the preset standard, including: inputting the semantic coding contrast feature map of the first-second transfer pattern images into a classifier-based pattern transfer quality evaluator to obtain an evaluation result, and the evaluation result is used to indicate whether the consistency between the transfer pattern of the first etched copper clad core board and the transfer pattern of the second etched copper clad core board meets the preset standard.

8. A double-sided circuit board with a double-sided copper embedded symmetrical structure, characterized in that: The double-sided copper-embedded symmetrical structure double-sided circuit board is manufactured by the preparation method of the double-sided copper-embedded symmetrical structure double-sided circuit board as claimed in any one of claims 1 to 7.

Images