FR4 manufacturing method using pure glue fusion

Abstract

The application provides a manufacturing method of FR4 using pure glue fusion. The manufacturing method of FR4 using pure glue fusion comprises the following steps: S1, providing an inner layer core plate, pure glue and a fusion jig; S2, placing the pure glue between the inner layer core plate and the upper jig and the lower jig; S3, placing the superimposed fusion jig, pure glue and inner layer core plate in a fusion device for heating and fusion; S4, after the fusion is completed, cooling the superimposed structure to room temperature; and S5, rolling the inner layer core plate with the pure glue adhered. The manufacturing method of FR4 using pure glue fusion provided by the application uses the upper and lower two-layer full-copper core plate jigs as carriers, and uses the fusion blocks on the jigs to locally heat and melt the pure glue for fusion and fixation, so that the pure glue can be accurately positioned without manual operation of an electric soldering iron, the influence of human factors on the production quality is eliminated, and the consistency and stability of batch production are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a method for manufacturing FR4 using pure adhesive bonding. Background Technology

[0002] With the rapid development of commercial aerospace technology, low-Earth orbit satellite constellations, with their significant advantages of low latency and high bandwidth, have become a core component of the global space-based information service infrastructure. Breakthroughs in rocket recovery technology have significantly reduced launch costs, driving satellite internet to expand from a single communication service to diversified applications such as remote sensing and IoT data acquisition. Against this macro background, onboard electronic equipment has placed unprecedentedly stringent requirements on the performance of printed circuit boards (PCBs), especially in high-frequency signal transmission scenarios. To ensure signal integrity and system reliability, PCB design often requires complex cavity structures filled with low-flow adhesive sheets (commonly known as "pure glue") to meet the special structural requirements of low-loss transmission of high-frequency signals and device mounting. The application of such special materials and structures poses new challenges to PCB manufacturing processes.

[0003] In existing PCB manufacturing processes, the traditional method of laminating FR4 substrates with pure adhesive mainly relies on specific specialized equipment or manual operation. A typical existing technology involves pre-fixing the pure adhesive using a high-speed press or a dummy-mount machine. The basic process of this method is as follows: first, the pure adhesive is cut to a size that matches the opening area of ​​the core board; then, the protective film on the surface of the pure adhesive is removed; and finally, the hot pressing function of the high-speed press or dummy-mount machine is used to temporarily fix the pure adhesive in a specific position on the core board. Finally, riveting and conventional pressing are performed. Although this method can achieve the positioning of the pure adhesive, its core drawback lies in its dependence on equipment. For manufacturing lines lacking specialized equipment such as high-speed presses or false-attach machines, this process is impossible to implement, severely limiting the versatility and flexibility of the production line. Furthermore, high-speed presses have long setup times and low production efficiency when processing large-area boards or multi-variety, small-batch products. Another more common existing technical solution is to use manual soldering irons for pure glue fixing in the absence of specialized equipment. This purely manual operation mode has serious technical drawbacks. This process requires dedicated personnel, who need to maintain a high level of concentration for extended periods, resulting in high labor intensity and a high risk of operational errors due to fatigue.

[0004] In summary, existing pure adhesive bonding processes are either limited by the configuration threshold of specialized equipment or by the instability of manual operation, making it impossible to achieve stable and efficient mass production of FR4 substrates without additional equipment investment.

[0005] Therefore, it is necessary to provide a method for manufacturing FR4 using pure glue to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a method for manufacturing FR4 using pure adhesive bonding, which solves the problems of high production threshold caused by reliance on special equipment and unstable production yield and poor consistency caused by manual use of soldering irons in the existing FR4 substrate pure adhesive bonding process.

[0007] To solve the above-mentioned technical problems, the present invention provides a method for manufacturing FR4 using pure glue fusion, comprising the following steps: S1: Provide an inner core board, pure glue, and a fusion fixture, wherein the fusion fixture includes an upper fixture and a lower fixture, and both the upper fixture and the lower fixture are provided with multiple fusion blocks; S2: The pure adhesive is placed between the inner core plate and the upper fixture and the lower fixture, and the pure adhesive is located between the fusion block of the fusion fixture and the inner core plate; S3: The stacked fusion fixture, the pure adhesive, and the inner core board are placed in a fusion device for heating and fusion, so that the pure adhesive located at the fusion block position is partially melted and adhered and fixed to the inner core board; S4: After fusion, cool the stacked structure to room temperature, separate and remove the upper fixture and the lower fixture; S5: Roll the inner core board with the pure adhesive adhering to it so that the pure adhesive is pre-attached to the surface of the inner core board.

[0008] Preferably, the fusion fixture adopts an all-copper core board structure, the fusion block is a solid copper block area on the all-copper core board, and the upper fixture and the lower fixture are respectively provided with multiple rivet hole modules, which are used for positioning in subsequent pressing processes.

[0009] Preferably, the fusion blocks are provided with 4 on each of the long sides and 2 on each of the short sides of the fusion fixture, for a total of 12; the rivet hole modules are provided with 3 on each of the long sides and 1 on each of the short sides of the fusion fixture, for a total of 8.

[0010] Preferably, the pure adhesive is a low-flow adhesive sheet, and when placed between the inner core plate and the fusion fixture, the pure adhesive retains a protective film on its surface, which is located between the pure adhesive and the fusion fixture.

[0011] Preferably, the fusion fixture is manufactured through the PCB inner layer production process, specifically including: material cutting, inner layer pattern making, inner layer etching, and inner layer punching.

[0012] Preferably, after the step of providing the inner core board and before the step of placing the pure adhesive between the inner core board and the fusion fixture, the method further includes a step of browning the inner core board, the browning treatment being used to increase the bonding strength between the inner core board and the pure adhesive.

[0013] Preferably, in the heating and fusion step, the fusion block acts as a heat conduction medium to transfer heat to the pure adhesive, causing a localized area of ​​the pure adhesive to melt.

[0014] Preferably, the rolling step is performed after the pure rubber molten area has solidified, and the mechanical pressure of the rolling machine makes the unmelted pure rubber area flat and adhere to the surface of the inner core board.

[0015] Preferably, after the rolling step, a riveting step is also included, in which the inner core board pre-attached with the pure adhesive is riveted to and positioned with other laminated structures.

[0016] Preferably, the riveting step utilizes the positioning holes formed by the rivet hole module reserved on the fusion fixture for positioning, and after the riveting is completed, a multilayer board pressing process is performed.

[0017] Compared with related technologies, the method for manufacturing FR4 using pure glue fusion provided by the present invention has the following beneficial effects: This invention provides a method for manufacturing FR4 using pure adhesive fusion. By employing a two-layer all-copper core board fixture as a carrier, and utilizing the fusion block on the fixture to locally heat-melt and fix the pure adhesive, the pure adhesive can be precisely positioned without manual operation of a soldering iron. Compared with the prior art that requires a dedicated person to manually operate the soldering iron, this method eliminates the impact of human factors on production quality, avoids yield fluctuations caused by personnel fatigue or differences in operating techniques, and significantly improves the consistency and stability of mass production. Attached Figure Description

[0018] Figure 1 A schematic flowchart of a method for manufacturing FR4 using pure glue fusion provided by the present invention; Figure 2 for Figure 1 The diagram shows the structure of the fusion fixture. Figure 3 for Figure 1 The diagram shows the production process of the fusion fixture.

[0019] The diagram is labeled as follows: 1. All-copper core board, 2. Fusion block, 3. Rivet hole module. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Please refer to the following: Figure 1 , Figure 2 and Figure 3 ,in, Figure 1 A schematic flowchart of a method for manufacturing FR4 using pure glue fusion provided by the present invention; Figure 2 for Figure 1 The diagram shows the structure of the fusion fixture. Figure 3 for Figure 1 The diagram shows the production process of the fusion fixture.

[0022] A method for manufacturing FR4 using pure glue fusion includes the following steps: S1: Provide an inner core board, pure glue, and a fusion fixture, wherein the fusion fixture includes an upper fixture and a lower fixture, and both the upper fixture and the lower fixture are provided with multiple fusion blocks; S2: The pure adhesive is placed between the inner core plate and the upper fixture and the lower fixture, and the pure adhesive is located between the fusion block of the fusion fixture and the inner core plate; S3: The stacked fusion fixture, the pure adhesive, and the inner core board are placed in a fusion device for heating and fusion, so that the pure adhesive located at the fusion block position is partially melted and adhered and fixed to the inner core board; S4: After fusion, cool the stacked structure to room temperature, separate and remove the upper fixture and the lower fixture; S5: Roll the inner core board with the pure adhesive adhering to it so that the pure adhesive is pre-attached to the surface of the inner core board.

[0023] The fusion fixture adopts a full copper core board structure, and the fusion block is a solid copper block area on the full copper core board. The upper fixture and the lower fixture are respectively provided with multiple rivet hole modules, which are used for positioning in the subsequent pressing process.

[0024] The fusion blocks are arranged in 4 on each of the long sides and 2 on each of the short sides of the fusion fixture, for a total of 12; the rivet hole modules are arranged in 3 on each of the long sides and 1 on each of the short sides of the fusion fixture, for a total of 8.

[0025] The pure adhesive is a low-flow bonding sheet. When placed between the inner core plate and the fusion fixture, the pure adhesive retains a protective film on its surface, which is located between the pure adhesive and the fusion fixture.

[0026] The fusion fixture is manufactured through the PCB inner layer production process, specifically including: material cutting, inner layer pattern making, inner layer etching, and inner layer punching.

[0027] After the step of providing the inner core board, and before the step of placing the pure adhesive between the inner core board and the fusion fixture, the method further includes a step of browning the inner core board, the browning treatment being used to increase the bonding strength between the inner core board and the pure adhesive.

[0028] In the heating and fusion step, the fusion block acts as a heat conduction medium to transfer heat to the pure adhesive, causing a localized area of ​​the pure adhesive to melt.

[0029] The rolling step is performed after the pure rubber molten area has solidified, and the mechanical pressure of the rolling machine makes the unmelted pure rubber area flat and adhere to the surface of the inner core board.

[0030] Following the rolling step, a riveting step is also included, in which the inner core board pre-attached with the pure adhesive is riveted and positioned to connect with other laminated structures.

[0031] The riveting step utilizes the positioning holes formed by the rivet hole module reserved on the fusion fixture for positioning. After riveting is completed, a multi-layer board pressing process is performed.

[0032] The inner core board is the core substrate of PCB products, and it is usually made of FR4 material (glass fiber reinforced epoxy resin copper clad board). In this embodiment, during the production process of the inner core board, the etching of the inner layer circuit pattern has been completed, and cavities or open areas are designed in specific positions for subsequent filling with pure glue to meet the needs of high-frequency signal transmission or device installation. Before the fusion step, the inner core board needs to undergo browning treatment. The browning process forms a micro-rough oxide layer on the surface of the inner core board. This oxide layer can significantly increase the bonding force between the resin material and the copper foil, preventing delamination during subsequent lamination or use.

[0033] Pure adhesive, also known in the industry as low-flow bonding sheet, is a semi-cured sheet composed solely of a resin system without fiberglass reinforcement. Due to its low flowability, it is less prone to overflow during heat pressing, making it particularly suitable for filling cavity structures. In this embodiment, the shape of the pure adhesive is pre-cut according to the cavity size on the inner core board. The surface of the pure adhesive is usually covered with a protective film, which is mostly made of polyethylene (PE) or polyethylene terephthalate (PET), mainly serving to prevent dust and adhesion. In the technical solution of this invention, the protective film on the upper layer of the pure adhesive is creatively retained, placing it between the pure adhesive and the fusion fixture, thus acting as an isolation layer to prevent the pure adhesive from adhering to the fixture when heated, facilitating the separation and reuse of the fixture.

[0034] The fusion fixture adopts an all-copper core plate structure, preferably made of electrolytic copper or rolled copper. It utilizes the excellent thermal conductivity of copper (thermal conductivity of about 400 W / m·K) to achieve rapid heat transfer.

[0035] The fusion fixture includes an upper fixture and a lower fixture, both of which are symmetrical in structure or mirror symmetrical according to the plate design. Both the upper fixture and the lower fixture are equipped with fusion blocks and rivet hole modules.

[0036] The fusion block is a solid copper block area on the fusion fixture. Its function is to act as a heat conduction medium to precisely guide the heat of the fusion device to a specific location of the pure adhesive. The design of the fusion block needs to take into account both fixing strength and heat conduction efficiency. In this embodiment, the thickness of the fusion block is the same as the thickness of the substrate of the fusion fixture 30 to ensure an unobstructed heat conduction path.

[0037] The rivet hole module is a pre-reserved positioning hole area on the fusion fixture, which is used to provide a positioning reference in the subsequent riveting process. By directly setting the rivet hole module on the fixture, the formation or calibration of the positioning hole can be completed simultaneously during the fusion process, which simplifies the process.

[0038] The fusion equipment is a conventional hot press or laminator in the existing technology, which does not require special modification. Its function is to provide a hot pressing environment so that the laminated fusion fixture, pure glue and inner core board are heated and pressurized.

[0039] The overall production process is mainly divided into two stages: the fusion fixture manufacturing stage and the lamination production stage. The fusion fixture manufacturing stage includes: material cutting, inner layer patterning, inner layer etching, and inner layer punching. This process is consistent with the conventional PCB inner layer board production process and can be completed using existing production lines. The lamination production stage includes browning, fusion, pre-lamination, riveting, and lamination. In the fusion step, the core is to use the pre-made fusion fixture as a heat conduction medium and positioning carrier to partially melt and adhere the pure adhesive to the inner layer core board. Subsequently, in the pre-lamination step, the pure adhesive is fully bonded to the board surface using a roll forming machine. The entire process is logically rigorous, and the combination of "point-like fusion fixing" and "overall roll forming" solves the problem of difficult positioning and bonding of pure adhesive.

[0040] The working principle of the FR4 manufacturing method using pure glue fusion provided by this invention is as follows: During operation, the inner core board, pure glue, and fusion fixture are first provided. The fusion fixture includes an upper fixture and a lower fixture, and several fusion blocks are provided on both the upper fixture and the lower fixture.

[0041] Then, pure adhesive is placed between the inner core plate and the upper and lower fixtures, with the pure adhesive located between the fusion block of the fusion fixture and the inner core plate. Next, the stacked fusion fixture, pure adhesive, and inner core plate are placed in the fusion equipment for heating and fusion. Heat conduction is used to partially melt the pure adhesive located at the fusion block position and adhere and fix it to the inner core plate.

[0042] After fusion, the stacked structure is cooled to room temperature, the upper and lower jigs are separated and removed, and finally, the inner core board with pure adhesive is rolled to pre-attach the pure adhesive to the surface of the inner core board.

[0043] The inner core board pre-bonded with pure adhesive is riveted to other stacked structures for positioning, utilizing conventional riveting processes in PCB production without altering the existing production rhythm.

[0044] Compared with related technologies, the method for manufacturing FR4 using pure glue fusion provided by the present invention has the following beneficial effects: This invention provides a method for manufacturing FR4 using pure adhesive fusion. By employing a two-layer all-copper core board fixture as a carrier, and utilizing the fusion block on the fixture to locally heat-melt and fix the pure adhesive, the pure adhesive can be precisely positioned without manual operation of a soldering iron. Compared with the prior art that requires a dedicated person to manually operate the soldering iron, this method eliminates the impact of human factors on production quality, avoids yield fluctuations caused by personnel fatigue or differences in operating techniques, and significantly improves the consistency and stability of mass production.

[0045] Furthermore, by setting a step to retain a protective film on the surface of the pure adhesive, a dual effect of anti-sticking and protection is achieved. The technical principle is that the protective film, as an isolation layer, prevents the low-flow adhesive sheet from accidentally adhering to the copper fixture when heated. This not only protects the surface quality of the pure adhesive but also avoids the fixture being contaminated by the adhesive, extending the service life of the fixture. At the same time, it simplifies the operation process of picking up and putting down the fixture and improves production efficiency.

[0046] Furthermore, since the fusion fixture is manufactured using a standard PCB inner layer production process, the technical solution of this invention can be fully embedded into existing PCB production lines. Compared with the existing technology that requires the purchase of expensive high-speed presses or false bonding machines, this invention does not require any new production equipment. It only needs to utilize existing inner layer manufacturing capabilities and conventional lamination equipment, thereby reducing the equipment investment costs and production operation costs of enterprises.

[0047] Furthermore, the multi-point arrangement of the fusion block design enables multi-point anchoring of the pure adhesive. Compared with traditional single-point or edge fixing, this multi-point fixing method can more effectively prevent the pure adhesive from warping or shifting during the transfer process. Especially for large-sized PNL boards, it ensures the relative positional accuracy between the pure adhesive and the core board, thereby guaranteeing the electrical connection reliability of the final product.

[0048] Furthermore, because this invention sets the pure adhesive fusion step after browning and before riveting, it forms a complete "browning-fusion-pre-lamination-riveting-pressing" production process. This process utilizes browning to enhance bonding strength, eliminates interlayer gaps through pre-lamination, and finally completes the finished product through riveting and pressing. This process does not require additional production steps, enabling this type of PCB product using pure adhesive to be mass-produced like ordinary FR4 products, greatly improving production efficiency and capacity.

[0049] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing FR4 using pure glue, characterized in that, Includes the following steps: S1: Provide an inner core board, pure glue, and a fusion fixture, wherein the fusion fixture includes an upper fixture and a lower fixture, and both the upper fixture and the lower fixture are provided with multiple fusion blocks; S2: The pure adhesive is placed between the inner core plate and the upper fixture and the lower fixture, and the pure adhesive is located between the fusion block of the fusion fixture and the inner core plate; S3: The stacked fusion fixture, the pure adhesive, and the inner core board are placed in a fusion device for heating and fusion, so that the pure adhesive located at the fusion block position is partially melted and adhered and fixed to the inner core board; S4: After fusion, cool the stacked structure to room temperature, separate and remove the upper fixture and the lower fixture; S5: Roll the inner core board with the pure adhesive adhering to it so that the pure adhesive is pre-attached to the surface of the inner core board.

2. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, The fusion fixture adopts a full copper core board structure, and the fusion block is a solid copper block area on the full copper core board. The upper fixture and the lower fixture are respectively provided with multiple rivet hole modules, which are used for positioning in the subsequent pressing process.

3. The method for manufacturing FR4 using pure glue according to claim 2, characterized in that, The fusion blocks are arranged in 4 on each of the long sides and 2 on each of the short sides of the fusion fixture, for a total of 12; the rivet hole modules are arranged in 3 on each of the long sides and 1 on each of the short sides of the fusion fixture, for a total of 8.

4. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, The pure adhesive is a low-flow bonding sheet. When placed between the inner core plate and the fusion fixture, the pure adhesive retains a protective film on its surface, which is located between the pure adhesive and the fusion fixture.

5. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, The fusion fixture is manufactured through the PCB inner layer production process, specifically including: material cutting, inner layer pattern making, inner layer etching, and inner layer punching.

6. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, After step S1, which provides the inner core board, and before step S2, which places the pure adhesive between the inner core board and the fusion fixture, the method further includes a step of browning the inner core board, wherein the browning treatment is used to increase the bonding force between the inner core board and the pure adhesive.

7. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, In the heating and fusion process of step S3, the fusion block acts as a heat conduction medium to transfer heat to the pure adhesive, causing a localized area of ​​the pure adhesive to melt.

8. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, The rolling step in step S5 is performed after the pure rubber molten area has solidified. The mechanical pressure of the rolling machine makes the unmelted pure rubber area flat and adhere to the surface of the inner core board.

9. The method for manufacturing FR4 using pure glue according to claim 1, characterized in that, Following the rolling step in step S5, a riveting step is also included, in which the inner core board pre-attached with the pure adhesive is riveted together with other laminated structures for positioning.

10. A method for manufacturing FR4 using pure glue according to claim 9, characterized in that, The riveting step utilizes the positioning holes formed by the rivet hole module reserved on the fusion fixture for positioning. After riveting is completed, a multi-layer board pressing process is performed.

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