A method for manufacturing a heat-dissipating copper-based PCB board

Abstract

This invention relates to the field of high heat dissipation copper-based printed circuit board manufacturing technology, and provides a method for manufacturing a heat-dissipating copper-based PCB board, comprising: firstly, processing large holes for resin filling on a bare copper plate; sealing one end of the large hole with dry film and using the other end as a resin injection channel; placing the bare copper plate horizontally with the dry film side down for vacuum resin plugging; then performing static shaping, horizontal curing baking, and natural cooling; subsequently removing the dry film; grinding the resin protruding above the copper surface to be flush with the board surface; stacking a prepreg and copper foil or sub-board on the bare copper plate to complete the lamination; finally, drilling conductive small holes in the resin layer and performing copper plating to achieve electrical conductivity. This invention, through the synergistic process of dry film sealing, vacuum plugging, and horizontal curing, overcomes the limitation of conventional plugging hole diameters not exceeding 1.2mm, and can reliably fill large holes of 1.0mm to 5.0mm, solving problems such as easy resin loss, incomplete filling, and air bubbles, significantly improving plugging quality and product reliability.

Description

Technical Field

[0001] This invention relates to the field of high heat dissipation copper-based printed circuit board manufacturing technology, and specifically to a method for manufacturing a heat-dissipating copper-based PCB board. Background Technology

[0002] With the rapid development of the electronics and information industry, printed circuit boards (PCBs), as the core components supporting electronic components and providing electrical interconnection, are seeing their application scenarios continuously expand. In fields such as power supplies, automotive electronics, and LED lighting, where heat dissipation and high current carrying capacity are stringent, conventional PCBs, with their low heat dissipation efficiency and limited current carrying capacity, can no longer meet the demands. Copper-based PCBs, with their excellent thermal conductivity and high current carrying capacity of copper, have become the preferred structure for high-heat-dissipation, high-power electronic products.

[0003] In the industry, PCBs using copper-based substrates or bare copper plates as the base material are collectively referred to as copper-based PCBs. Among them, those with a copper thickness of ≥0.4mm and high thermal conductivity resin are copper-based, while pure copper plates without a resin layer are bare copper plates. According to structural differences, heat-dissipating copper-based PCBs can be divided into copper-based reinforcing plates and buried copper-based PCBs. Buried copper-based PCBs usually use bare copper plates as the core heat dissipation layer. The copper substrate only undertakes the heat dissipation function and does not participate in circuit conduction. Therefore, the electrical interconnect holes in the board must be reliably insulated from the copper substrate.

[0004] Currently, copper-based PCBs commonly employ a large-hole-within-a-small-hole insulation structure: first, a large hole is machined on the copper substrate and filled with resin; then, a small hole is drilled in the center of the resin to achieve electrical conductivity, with the resin layer providing electrical isolation between the small hole and the copper substrate. To ensure insulation safety and prevent short circuits between the copper layer on the hole wall and the copper substrate, engineering practices require that the large hole on the copper substrate be enlarged by 1.0 mm from the diameter of the finished small hole. The resulting large hole size often exceeds the processing capacity of conventional resin-filled holes.

[0005] The maximum hole diameter that can be stably processed by the existing conventional resin plugging process is only 1.2mm. Once this limit is exceeded, problems such as incomplete filling will occur, and defects such as voids, bubbles, depressions, and resin contamination are prone to occur, leading to insulation failure, delamination and cracking, and poor processing in subsequent processes. This directly results in low plugging yield, poor reliability, and high scrap rate, making resin plugging of large-diameter copper-based insulating holes a long-standing technical bottleneck in the industry, which seriously restricts the large-scale production and performance improvement of buried copper-based high heat dissipation PCBs. Summary of the Invention

[0006] In view of this, the problem to be solved by the present invention is to provide a method for manufacturing a heat-dissipating copper-based PCB board.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for manufacturing a heat-dissipating copper-based PCB board includes the following steps: S1. Drill holes in the copper plate to form large holes for filling with resin; S2. Apply a dry film to the surface of the drilled copper plate, so that the dry film covers one end of the hole and the other end of the hole is used as a resin injection channel. S3. Place the copper plate with the dry film attached horizontally with the dry film side down, and perform vacuum resin plugging, so that the resin ink fills the large holes under the vacuum negative pressure. S4. Perform static shaping and horizontal curing baking on the bright copper plate, and allow it to cool naturally to room temperature after baking. S5. After cooling, perform a film removal process to remove the dry film covering one end of the large pore, so that the resin filling the large pore is fully exposed. S6. Grind the surface of the copper plate to smooth out the resin protruding above the copper surface until it is flush with the surface of the copper plate. S7. Stack prepreg and copper foil or sub-board on the surface of the copper plate and perform a lamination operation. S8. Drill small holes for electrical conduction in the pressed resin layer; S9. Perform copper plating on the small hole to form a conductive copper layer on the hole wall.

[0008] The diameter of the large hole ranges from 1.0 mm to 5.0 mm; the diameter of the small hole ranges from 0.2 mm to 4.0 mm; the thickness of the copper plate is ≥ 0.4 mm; and the large hole is 0.4 mm larger on one side than the small hole.

[0009] The vacuum degree of the vacuum resin plug is 80kPa~100kPa. When injecting the resin, the copper plate is kept in a horizontal and static state with the film-coated side facing down.

[0010] The heating rate for horizontal curing baking is 2.0℃ / min to 2.2℃ / min, the total baking time is 150min, and the natural cooling process is completed inside the oven.

[0011] The surface of the bare copper plate after the film is removed is ground using a ceramic grinding plate equipment, which involves sequentially performing belt grinding, ceramic abrasive grinding, and non-woven fabric grinding and polishing.

[0012] The pressing operation was performed at a temperature of 210℃, a pressing pressure of 420 PSI, and a pressing time of 150 min.

[0013] In S2, after the film is applied, an exposure process is performed to allow the dry film to fully cure and firmly adhere to the surface of the copper plate, forming a reliable sealing layer to prevent resin leakage from the film side.

[0014] The small hole is located at the center of the large hole, forming a concentric structure. The resin layer inside the large hole isolates the copper base from the small hole, achieving electrical insulation.

[0015] The horizontal curing and baking process adopts a segmented heating method: first, the temperature is raised to 120℃ and held for 60 minutes, then the temperature is raised to 150℃ and held for 30 minutes; the heating rate is 2.0℃ / min to 2.2℃ / min, and the total baking time is 150 minutes.

[0016] The advantages and positive effects of this invention are: (1) By combining dry film single-sided sealing, vacuum negative pressure plugging and horizontal static curing, the technical limitation that conventional resin plugging is only applicable to pores with a diameter of no more than 1.2 mm has been successfully overcome. It can reliably fill large-diameter insulating holes of 1.0 mm to 5.0 mm, fundamentally solving industry problems such as easy loss of large-pore resin, incomplete filling, and the presence of air bubbles and voids. It significantly improves plugging quality and production yield. The yield of plugging can reach more than 90% in one pass, and 100% yield can be achieved in two passes, effectively reducing product scrap rate.

[0017] (2) A concentric insulation structure with the large hole being 0.4 mm larger on one side than the small hole is adopted, and a curing method of segmented heating and baking and natural cooling in the oven is used to ensure that the resin insulation layer is thick enough, the insulation resistance between the copper base and the conductive hole is greater than 300MΩ, the insulation is safe and reliable, and there is no breakdown or short circuit. It can also avoid the resin from cracking, deforming and falling off due to thermal stress, so that the resin and the hole wall are firmly bonded and do not delaminate after long-term use, which greatly improves the structural stability and electrical reliability of the product.

[0018] (3) Using a copper plate with a thickness of ≥0.4mm as the overall heat dissipation layer, the high thermal conductivity of copper material is used to achieve efficient heat dissipation. At the same time, the board surface is flat and neat after three ceramic grinding processes, which can stably adapt to copper foil or sub-board lamination and is compatible with double-layer and multi-layer PCB structures. The overall process has a high degree of matching with conventional PCB processes, does not require major modification of production equipment, has strong production stability and consistency, and is easy to scale up production and promotion. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0020] In the attached diagram: Figure 1 This is an overall flowchart of a method for manufacturing a heat-dissipating copper-based PCB board according to the present invention; Figure 2 This is a cross-sectional view of a copper-based PCB board manufactured using the heat-dissipating copper-based PCB board manufacturing method of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] To address the problems in existing technologies, this application, through continuous experimental research, has discovered that the maximum stable hole diameter that can be processed by the existing conventional resin plugging process is only 1.2 mm. This limitation is due to the fact that when the hole diameter is greater than 1.2 mm, the resin ink has insufficient adhesion to the hole wall and flows out of the hole before entering the baking and curing stage, failing to achieve full filling. Even if it manages to flow in, defects such as voids, bubbles, depressions, and resin contamination are likely to occur, leading to insulation failure, delamination and cracking, and poor subsequent processing. Therefore, this invention provides a method for manufacturing a heat-dissipating copper-based PCB board to solve the above problems.

[0025] Furthermore, the specific embodiments of the present invention will be described in detail with reference to specific process steps and parameters, illustrating the manufacturing method of the heat-dissipating copper-based PCB board. The specific embodiments described below are only used to further illustrate the technical solution of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0026] This invention uses a bare copper plate as the substrate. The bare copper plate is a pure copper plate without resin, with a copper thickness ≥0.4mm. It is used as the copper base in heat-dissipating copper-based PCBs, primarily for heat dissipation and not involved in electrical conduction. Before use, the bare copper plate needs to be cut to the required size. After cutting, the plate undergoes degreasing and cleaning to remove oil, impurities, and oxide layers, ensuring a clean surface and providing a good surface condition for subsequent drilling processes.

[0027] After cleaning and drying, the bare copper board enters the drilling process. Drilling is done using a CNC drilling machine, drilling large holes for resin filling and positioning holes for positioning on the bare copper board according to the design documents. When drilling large holes, the diameter ranges from 1.0mm to 5.0mm, with the specific diameter determined by the final diameter of the small holes on the PCB board. The large holes are drilled on the bare copper board to fill the resin insulation, while the small holes are drilled in the center of the resin to conduct electricity and connect the upper and lower layers. Because the outer layer of the heat-dissipating copper-based PCB board uses thick copper, and due to limitations in mechanical drilling, copper plating, and insulation structure design, the minimum diameter of the small holes is 0.2mm, and the maximum diameter is 4.0mm. The diameter of the large holes on the copper base needs to be 0.4mm larger on one side than the small holes, meaning the total diameter of the large holes is 1.0mm larger than the total diameter of the small holes. Therefore, the diameter range of the large holes on the copper base is determined to be 1.0mm to 5.0mm. High-hardness drill bits are required for drilling. The drill speed and feed rate need to be adjusted according to the thickness of the copper plate and the hole diameter to ensure smooth, burr-free hole walls. The drilling accuracy of the positioning holes must be within ±0.05mm to ensure accurate alignment in subsequent processes. After drilling, the copper plate needs to be cleaned to remove copper shavings and dust generated during drilling.

[0028] After drilling, the copper plate proceeds to the film lamination and exposure process. The film used is Changxing E9420 dry film, a photosensitive polymer film that polymerizes and cures under ultraviolet light. A laminating machine is used to evenly apply the dry film to one side of the copper plate at a speed of 2.5 m / min and a pressure of 3.5 kg / cm². Under pressure, the dry film adheres tightly to the copper plate surface, completely sealing one end of the drilled hole to form a sealing layer, while the other end remains open as a channel for subsequent resin injection. After lamination, exposure is required to fully cure the dry film under ultraviolet light and ensure it adheres firmly to the copper plate surface, forming a reliable sealing layer and preventing resin leakage from the laminated side. The ultraviolet lamp used for exposure has a wavelength of 365 nm or 405 nm, and the exposure energy is determined based on the dry film type and thickness, typically ranging from 80 mJ / cm² to 150 mJ / cm². After exposure, a developing process is required to remove the uncured dry film and leave the cured dry film pattern on the surface of the copper plate.

[0029] After the copper plate has undergone film application and exposure, it enters the resin plugging process. Resin plugging employs a vacuum plugging method using specialized vacuum plugging equipment. A negative pressure environment is created within the vacuum chamber, allowing the resin ink to be injected into the large holes. The vacuum negative pressure ensures the resin fully fills every corner of the large holes, preventing air bubbles and incomplete filling. Before plugging, the copper plate with the dry film applied is placed on a horizontal worktable with the dry film side down, maintaining a horizontal and static state for at least 0.5 hours to stabilize it in a horizontal position. The resin ink used is Bairou PHP9000-3F-ST low CTE resin, which has a low coefficient of thermal expansion, minimal volume shrinkage with temperature changes, strong adhesion to the copper plate, and good insulation properties. The ink viscosity needs to be adjusted to 300–500 dPa. For example, excessively high viscosity can lead to filling difficulties, while excessively low viscosity can cause leakage. The vacuum level of the vacuum plugging device is 80kPa to 100kPa. Under the action of vacuum negative pressure, the resin ink is injected into the large hole. Since the copper plate is kept in a horizontal and static state with the film-coated side facing down, the resin flows downward under the action of gravity and fully fills the entire large hole, ensuring that the resin is fully filled and free of air bubbles. The dry film seals one end of the hole to prevent resin leakage.

[0030] After resin filling, the bright copper plate enters the baking process for resin curing. A horizontal oven is used, with the bright copper plate placed stably on the oven tray. The baking process employs a segmented heating method. First, the oven temperature is raised from room temperature to 120℃ at a rate of 2.0℃ / min to 2.2℃ / min, and held at 120℃ for 60 minutes to allow the resin to initially cure, undergoing a cross-linking reaction to form a preliminary network structure. Then, the temperature is raised from 120℃ to 150℃ at the same rate of 2.0℃ / min to 2.2℃ / min, and held at 150℃ for 30 minutes to completely cure the resin, forming a dense network structure. The cured resin exhibits good insulation properties and mechanical strength. The total baking time is 150 minutes, including the heating and holding times. After baking, allow the copper plate to cool naturally to room temperature inside the oven. Forced cooling is strictly prohibited during this process. Using fans or water cooling will cause the resin to crack or shrink due to thermal expansion and contraction, affecting the bonding strength between the resin and the hole walls. The natural cooling process is completed inside the oven, and the cooling time depends on the oven's insulation performance and the thickness of the copper plate, requiring 2 to 4 hours.

[0031] After natural cooling, the copper substrate enters the stripping process. A specialized stripping solution is used, which can be an alkaline sodium hydroxide solution or a dedicated stripping agent. The copper substrate is immersed in the stripping solution, or the solution is sprayed evenly onto its surface. The stripping solution reacts chemically with the dry film, causing the cured dry film to detach from the copper substrate surface. After stripping, the copper substrate is rinsed with clean water to remove residual stripping solution and detached dry film fragments, and then dried. After stripping, the resin filling the large pores is fully exposed, and the resin has cured within the pores to form a solid plug.

[0032] After the coating is removed, the polished copper plate enters the ceramic grinding process. The purpose of ceramic grinding is to remove the resin protruding above the surface of the polished copper plate and smooth out the resin protruding from the orifices, making the resin surface flush with the surface of the polished copper plate, providing a good surface condition for the subsequent lamination process. Ceramic grinding is performed using specialized equipment, and the grinding process consists of three steps. The first step uses abrasive belts for coarse grinding, with a grit size of 80-120 mesh, to remove most of the resin protruding above the surface of the polished copper plate. The grinding amount is determined according to the height of the resin protrusion, typically 0.1mm-0.3mm. The second step uses ceramic abrasive for fine grinding, with a grit size of 200-400 mesh, to make the resin surface basically flat and eliminate scratches left by coarse grinding. The third step uses non-woven fabric for polishing. The non-woven fabric is made of polyester or nylon fiber, used to polish the resin surface to a smooth state. The ceramic grinding plate operates at a linear speed of 2.5 m / min and a current of 1.5 A to 2.0 A. The copper plate is ground twice on each side during the grinding process to ensure uniform surface flatness. After grinding, the copper plate needs to be cleaned to remove dust and debris generated during grinding.

[0033] After grinding, the bare copper board enters the lamination process. Lamination is a crucial step in firmly bonding the bare copper board to prepreg and copper foil or sub-board. Before lamination, prepreg and copper foil, or prepreg and sub-board, are stacked sequentially on both sides of the bare copper board. Prepreg is a pre-impregnated adhesive material that flows and cures under high temperature and pressure, firmly bonding the copper foil or sub-board to the bare copper board. The thickness and type of prepreg are selected based on the number of layers and requirements of the PCB board; typically, prepreg with a resin content of 50%–70% is used. The lamination machine used is a vacuum laminator or a hot press. During lamination, a vacuum is first evacuated to remove interlayer air bubbles, followed by pressure and heating. The maximum lamination temperature is 210℃, the heating rate is 2.0℃ / min–2.2℃ / min, the lamination pressure is 420 PSI, and the lamination time is 150 min. Under high temperature and pressure, the prepreg flows and fills the gaps between the layers, then undergoes a curing reaction to form a robust laminate structure. After lamination, it needs to be held under pressure and cooled to room temperature before being released and removed. The removed laminate requires post-curing treatment to ensure the prepreg is fully cured.

[0034] After lamination, the laminate enters the drilling process, where small holes for electrical conduction are drilled into the resin layer. Drilling is done using a CNC drilling machine, with the holes drilled at the center of the resin layer according to the design documents. The diameter of these small holes ranges from 0.2mm to 4.0mm. The small holes are located at the center of the larger holes, forming a concentric structure. The resin layer within the larger holes isolates the copper substrate from the small holes, achieving electrical insulation. High-precision drill bits are required during drilling to ensure the positional and diameter accuracy of the small holes. After drilling, the holes are cleaned to remove copper shavings and dust.

[0035] After drilling, the laminate enters the copper plating process to give the small holes electrical conductivity between the upper and lower layers. Copper plating consists of two steps: copper deposition and electroplating. Copper deposition uses a chemical deposition method to deposit a thin copper layer on the surface of the resin hole walls. The copper deposition solution is an alkaline copper ion solution containing copper sulfate, formaldehyde, sodium hydroxide, etc. Formaldehyde acts as a reducing agent, reducing copper ions to metallic copper which is deposited on the hole wall surface. The copper deposition time is determined according to the hole diameter and the required copper layer thickness, typically 15 to 30 minutes. After copper deposition, a copper layer of approximately 0.5 μm to 1 μm thick is formed on the hole wall surface. Electroplating uses an acidic copper sulfate solution to thicken the thin copper layer formed by copper deposition. The electroplating current density is 15 A / dm² to 25 A / dm², and the electroplating time is determined according to the required copper thickness, typically 30 to 60 minutes, to achieve a copper thickness of 25 μm to 35 μm, meeting the requirements for electrical conductivity. After copper plating, cleaning and drying are performed.

[0036] After copper plating, the laminate enters the outer layer pattern fabrication process, following standard PCB manufacturing procedures. Outer layer pattern fabrication includes steps such as pattern transfer, etching, and post-processing. Pattern transfer uses dry or wet film as a resist to transfer the designed outer layer pattern to the laminate surface. Etching then removes unwanted copper layers, forming the designed circuit pattern. After outer layer pattern fabrication, surface treatments such as immersion tin, gold plating, or OSP treatment are applied to improve solderability and oxidation resistance.

[0037] The heat-dissipating copper-based PCB board manufactured using the method of this invention has the following advantages: Due to the special process combining dry film sealing, vacuum plugging, horizontal baking, and ceramic grinding, the problem of resin plugging for large holes larger than 1.2mm in diameter is successfully solved, enabling reliable resin plugging for large holes in the 1.0mm to 5.0mm diameter range. The yield rate for one-time plugging can reach over 90%, and for two-time plugging, it can reach 100%. The horizontal static placement with the film side down utilizes gravity to ensure the resin fully fills and adheres tightly to the hole wall. The segmented heating baking and natural cooling process parameters effectively prevent resin cracking or shrinkage during curing. The three grinding processes of the ceramic grinding ensure the smoothness of the resin surface, providing a good surface condition for subsequent lamination and drilling processes. The finished heat-dissipating copper-based PCB board has an insulation resistance greater than 300MΩ between the copper base and the small holes, meeting the requirements of high-reliability products. The heat dissipation coefficient of the PCB is 0.3W / (m·K), and the heat dissipation coefficient of copper is 400W / (m·K), achieving excellent heat dissipation performance.

[0038] The specific embodiments described above are only used to illustrate the technical solutions of the present invention. Those skilled in the art can make various modifications and changes within the scope of the technical solutions of the present invention, and all such modifications and changes should be covered within the protection scope of the present invention.

[0039] The working principle and process of this invention are as follows: Using a copper plate with a thickness of not less than 0.4mm as the core heat dissipation substrate, a complete process flow is used to achieve stable production of a highly reliable heat dissipation copper-based PCB board. This process includes material preparation and cleaning, drilling, single-sided dry film sealing, vacuum plugging, horizontal placement, segmented baking and curing, natural cooling, film removal, ceramic multi-level grinding, multi-layer lamination, concentric drilling, copper plating, and outer layer pattern making.

[0040] First, the bare copper plate is cut and cleaned to remove surface oil, impurities, and oxide layers, ensuring the bonding quality for subsequent drilling, film application, and hole plugging. Then, large holes ranging from 1.0mm to 5.0mm are machined on the bare copper plate. This hole diameter is designed based on a 0.4mm enlargement on one side of the conductive via size, allowing sufficient thickness for the resin insulation layer and structurally preventing short circuits between the copper base and the conductive via. After drilling, a dry film is used to seal the large hole opening on one side, forming a closed cavity open only on one side. This provides an injection channel for the resin and fundamentally prevents resin leakage during the filling and curing stages.

[0041] The sealed copper plate is placed horizontally with the dry film side down, and then vacuum negative pressure is applied to plug the holes. This allows the resin to expel air bubbles in a vacuum environment and completely fill the large holes under the combined action of negative pressure and gravity, achieving a full filling without air bubbles, voids, or missing material. Next, it undergoes segmented heating and baking. First, it is held at 120℃ for 60 minutes to allow the resin to initially cross-link and set, then the temperature is increased to 150℃ and held for 30 minutes to achieve complete curing. Natural cooling within the oven is used to prevent internal stress, cracking, or shrinkage deformation caused by sudden temperature changes, ensuring a strong bond between the resin and the copper wall. After cooling, the film is removed to fully expose the cured resin. Then, three processes—rough grinding with a sanding belt, fine grinding with ceramic, and polishing with non-woven fabric—are used to smooth the resin protruding above the copper surface until it is flush with the copper surface, improving the flatness of the board and ensuring the quality of subsequent lamination.

[0042] After grinding, the polished copper board is laminated with prepreg, copper foil, or sub-board under high temperature and pressure to form a stable laminated structure. After lamination, conductive vias of 0.2mm to 4.0mm are drilled in the resin layer at the center of the large holes, forming a concentric insulating structure with large holes surrounding smaller ones. The resin layer completely isolates the copper base from the conductive vias. Finally, copper plating is applied to the vias to form a uniform conductive copper layer on the via walls, enabling electrical conduction between the upper and lower layers. This allows the copper base to retain only its efficient heat dissipation function and not participate in circuit conduction, ultimately resulting in a heat-dissipating copper-based PCB board with reliable insulation, excellent heat dissipation, stable structure, and suitability for mass production.

[0043] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A method for manufacturing a heat-dissipating copper-based PCB board, characterized in that, Includes the following steps: S1. Drill holes in the copper plate to form large holes for filling with resin; S2. Apply a dry film to the surface of the drilled copper plate, so that the dry film covers one end of the hole and the other end of the hole is used as a resin injection channel. S3. Place the copper plate with the dry film attached horizontally with the dry film side down, and perform vacuum resin plugging, so that the resin ink fills the large holes under the vacuum negative pressure. S4. Perform static shaping and horizontal curing baking on the bright copper plate, and allow it to cool naturally to room temperature after baking. S5. After cooling, perform a film removal process to remove the dry film covering one end of the large pore, so that the resin filling the large pore is fully exposed. S6. Grind the surface of the copper plate to smooth out the resin protruding above the copper surface until it is flush with the surface of the copper plate. S7. Stack prepreg and copper foil or sub-board on the surface of the copper plate and perform a lamination operation. S8. Drill small holes for electrical conduction in the pressed resin layer; S9. Perform copper plating on the small hole to form a conductive copper layer on the hole wall.

2. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. The diameter of the large hole ranges from 1.0 mm to 5.0 mm; the diameter of the small hole ranges from 0.2 mm to 4.0 mm; the thickness of the copper plate is ≥ 0.4 mm; and the large hole is 0.4 mm larger on one side than the small hole.

3. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. The vacuum degree of the vacuum resin plug is 80kPa~100kPa. When injecting the resin, the copper plate is kept in a horizontal and static state with the film-coated side facing down.

4. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. The heating rate for horizontal curing baking is 2.0℃ / min to 2.2℃ / min, the total baking time is 150min, and the natural cooling process is completed inside the oven.

5. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. The surface of the bare copper plate after the film is removed is ground using a ceramic grinding plate equipment, which involves sequentially performing belt grinding, ceramic abrasive grinding, and non-woven fabric grinding and polishing.

6. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. The pressing operation was performed at a temperature of 210℃, a pressing pressure of 420 PSI, and a pressing time of 150 min.

7. The method of claim 1, wherein the copper-based PCB is a heat-dissipating copper-based PCB. In S2, after the film is applied, an exposure process is performed to allow the dry film to fully cure and firmly adhere to the surface of the copper plate, forming a reliable sealing layer to prevent resin leakage from the film side.

8. The method for manufacturing a heat-dissipating copper-based PCB board according to claim 1, characterized in that, The small hole is located at the center of the large hole, forming a concentric structure. The resin layer inside the large hole isolates the copper base from the small hole, achieving electrical insulation.

9. The method for manufacturing a heat-dissipating copper-based PCB board according to claim 1, characterized in that, The horizontal curing and baking process adopts a segmented heating method: first, the temperature is raised to 120℃ and held for 60 minutes, then the temperature is raised to 150℃ and held for 30 minutes; the heating rate is 2.0℃ / min to 2.2℃ / min, and the total baking time is 150 minutes.

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