A method for manufacturing PCB with pre-embedded edges
By extending along the edge of the PCB subboard and pre-grooving grooves on the multilayer substrate to form embedded grooves, the problems of resin voids and unevenness at the subboard/motherboard connection point are solved, achieving PCB production with high reliability and high yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-13
- Publication Date
- 2026-05-26
AI Technical Summary
In the prior art, when the thicker sub-board or the embedded area is located at the edge of the PCB board, resin voids are prone to occur at the sub/mother board connection point, leading to scrap. At the same time, the mismatch between the depth of the mother board groove and the thickness of the sub-board results in unevenness of the board surface, affecting the reliability, signal integrity and heat dissipation performance of the PCB board, and increasing production costs.
By designing the edge of the PCB sub-board to extend outward beyond the edge of the finished board, and pre-grooving grooves are made on the composite substrate of the multi-layer PCB motherboard core board and prepreg stacked in an alternating manner to form embedded grooves, the resin at the interface between the sub-board and the motherboard is ensured to be full, and the edge is cut after lamination to form an edge embedded structure.
This solved the resin void problem, ensured the flatness of the board surface, improved the reliability, signal integrity and heat dissipation performance of the PCB board, and reduced production costs while increasing the yield rate.
Smart Images
Figure CN122094038A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of printed circuit board technology, and more specifically, to a method for manufacturing a PCB with pre-embedded edges. Background Technology
[0002] A PCB (Printed Circuit Board) is a carrier for the electrical interconnection of electronic components. Based on functional differences and actual electronic signal requirements, it is classified into ordinary boards, high-frequency boards, and metal-based boards. A hybrid lamination structure, which uses two or more substrate materials with different properties, can simultaneously meet the needs of digital and radio frequency signal transmission.
[0003] Embedded technology is a design that embeds high-frequency materials into ordinary materials based on the structure of ordinary materials and according to the application requirements. Its core is to reduce material costs and improve the electrical functions and high integration of electrical signals of PCB boards. Existing embedding processes typically involve prefabricating a core board and laminating it once to form a motherboard structure. A CNC milling machine then mills grooves of the pre-designed depth to create a grooved PCB motherboard. Simultaneously, a daughterboard is milled to the corresponding dimensions. During the second lamination, the daughterboard and prepreg are embedded into the grooves, completing the lamination process to form a single unit, upon which circuitry is then fabricated. However, existing technologies can only embed daughterboards of a certain thickness (approximately 0.5mm). For thicker daughterboards or when the embedding area is at the edge of the PCB, resin voids appear at the daughterboard / motherboard connection, leading to scrap. Furthermore, the mismatch between the motherboard groove depth and the daughterboard thickness results in uneven board surfaces. Summary of the Invention
[0004] To overcome the shortcomings of the prior art, the present invention provides a method for manufacturing an edge-embedded PCB, which can solve the problems in the prior art where resin voids occur at the connection position of the sub-board and motherboard when the sub-board is thick or the embedded area is located at the edge of the PCB board, resulting in scrap, and the problem that the depth of the motherboard groove does not match the thickness of the sub-board, resulting in uneven board surface. This improves the reliability, signal integrity and heat dissipation performance of the PCB board, while reducing production costs and increasing yield.
[0005] The technical solution adopted by this invention to solve its technical problem is: a method for manufacturing an edge-embedded PCB, wherein the improvement is that the edge-embedded PCB manufacturing method includes: Fabricate a PCB sub-board, wherein at least one edge of the PCB sub-board is designed to extend outward beyond the corresponding edge of the finished PCB; A composite substrate consisting of a multilayer PCB motherboard core board and a prepreg stacked alternately is fabricated, and pre-grooves are made on the composite substrate corresponding to the embedding positions of the PCB sub-board to form embedding grooves. The PCB sub-board and the pre-grooved composite substrate are stacked, so that the PCB sub-board is housed in the embedded groove, and then pressed together, so that the PCB sub-board, the prepreg and the PCB motherboard core board are combined into one, and the extended edge of the PCB sub-board protrudes beyond the edge of the composite board formed after pressing. The laminated composite board is cut along the designed edge lines to form a finished PCB board with an edge embedding structure.
[0006] Furthermore, the edge of the PCB sub-board extends outward by approximately 1.0 mm.
[0007] Furthermore, during the process of pre-grooving the PCB sub-board at the embedded position on the combined substrate, the PCB motherboard core board and the prepreg corresponding to the embedded position of the PCB sub-board need to be pre-grooved respectively.
[0008] Furthermore, the width of the grooves on the PCB motherboard core board is 4-8 mil wider than the width of the PCB daughterboard.
[0009] Furthermore, the groove width of the prepreg is 10-14 mil wider than the width of the PCB subboard.
[0010] Furthermore, the depth of the embedded groove is 0-0.05mm greater than the thickness of the PCB sub-board.
[0011] Furthermore, the method for manufacturing the PCB sub-board is as follows: Cut the copper-clad laminate into PCB sub-board substrates according to the design dimensions, and etch the PCB sub-board circuit pattern on one side of the PCB sub-board substrate; The PCB sub-board circuit pattern is cut according to the design shape to form the PCB sub-board.
[0012] Furthermore, the method for manufacturing the composite substrate includes: Cut multiple PCB motherboard cores from copper-clad laminate according to the design dimensions, etch PCB motherboard core circuit patterns on one side of each PCB motherboard core, and cut multiple prepreg sheets of the same size as the PCB motherboard cores. Pre-grooving is performed on the PCB motherboard core board and prepreg according to the design dimensions; The PCB motherboard core board and the prepreg are stacked in an alternating manner to form a composite substrate.
[0013] The beneficial effects of this invention are as follows: By designing at least one edge of the PCB sub-board to extend outward beyond the corresponding edge of the finished PCB, and by cutting the edge line after lamination, this invention ensures that the resin at the interface between the PCB sub-board and the PCB motherboard core board is full, thus structurally eliminating voids at the board edge. By pre-grooving grooves on a composite substrate consisting of multiple layers of PCB motherboard core boards and prepreg stacked alternately, corresponding to the embedding position of the PCB sub-board, a preliminary positioning reference for embedding the PCB sub-board can be provided. Furthermore, the depth of the embedding groove can be adaptively adjusted to the thickness of the PCB sub-board to ensure the flatness of the finished PCB board surface after lamination. Therefore, this invention can solve the problems in the prior art where resin voids at the sub / motherboard connection point lead to scrap when the sub-board is thicker or the embedding area is at the edge of the PCB board, and where the mismatch between the depth of the motherboard groove and the thickness of the sub-board leads to uneven board surfaces. This improves the reliability, signal integrity, and heat dissipation performance of the PCB board, while reducing production costs and increasing yield. Attached Figure Description
[0014] Figure 1 This is a flowchart of a method for manufacturing an edge-embedded PCB according to the present invention; Figure 2 This is a schematic diagram illustrating the structure of the finished PCB board manufacturing process as an example embodiment. Figure 1 ; Figure 3 This is a schematic diagram illustrating the structure of the finished PCB board manufacturing process as an example embodiment. Figure 2 ; Figure 4 This is a schematic diagram illustrating the structure of the finished PCB board manufacturing process as an example embodiment. Figure 3 . Detailed Implementation
[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0016] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.
[0017] Reference Figures 1-4As shown, the present invention provides a method for manufacturing an edge-embedded PCB, the method comprising: S10, fabricate a PCB sub-board, wherein at least one edge of the PCB sub-board is designed to extend outward beyond the corresponding edge of the finished PCB. Specifically, the fabrication method of the PCB sub-board is as follows: The copper-clad laminate is cut into PCB sub-board substrates according to the design dimensions, and PCB sub-board circuit patterns are etched on one side of the PCB sub-board substrate. In this embodiment, the material (such as FR-4, High-Tg or special high-frequency material) and thickness of the copper-clad laminate need to be precisely selected according to the electrical performance, thermal performance and mechanical strength requirements of the final product. When etching the pattern, a high-precision exposure and etching process must be used to ensure the accuracy of the sub-board circuit, which is the key to ensuring the sub-board function and subsequent alignment. The PCB sub-board circuit pattern is cut according to the design shape to form the PCB sub-board; In addition, the edge of the PCB sub-board extends outward by about 1.0mm, so that the embedded PCB sub-board covers the edge of the finished PCB, thus ensuring the reliability of the embedded PCB edge bonding. Specifically, the purpose of designing at least one edge of the sub-board to extend outward by about 1.0mm is to ensure that the bonding interface between the sub-board and the motherboard is ultimately located "inside" of the edge of the finished board. In the final cutting process of S40, this extended 1.0mm portion will be removed. This completely eliminates resin voids at the board edge, because during lamination, the resin will fill the entire bonding interface and wrap the extended portion. Cutting is equivalent to removing the "process buffer" that may have microscopic defects, thereby exposing a brand-new cross-section filled with completely dense resin and firmly bonded, which greatly improves the mechanical reliability and environmental stress resistance of the board edge area. S20, fabricating a composite substrate consisting of a multilayer PCB motherboard core board and prepreg stacked alternately, and pre-riveting grooves on the composite substrate corresponding to the embedding positions of the PCB daughter boards to form embedding recesses; specifically, the fabrication method of the composite substrate includes: Cut multiple PCB motherboard cores from copper-clad laminate according to the design dimensions, etch PCB motherboard core circuit patterns on one side of each PCB motherboard core, and cut multiple prepreg sheets of the same size as the PCB motherboard cores. Pre-grooving is performed on the PCB motherboard core board and prepreg according to the design dimensions; The PCB motherboard core board and the prepreg are stacked in an alternating manner to form a composite substrate; In addition, during the pre-grooving process on the combined substrate corresponding to the embedding position of the PCB sub-board, the PCB motherboard core board and the prepreg corresponding to the embedding position of the PCB sub-board need to be pre-grooved separately; furthermore, the groove width of the PCB motherboard core board is 4-8 mil larger than the width of the PCB sub-board; the groove width of the prepreg is 10-14 mil larger than the width of the PCB sub-board; the depth of the embedding groove is 0-0.05 mm larger than the thickness of the PCB sub-board; wherein, the design that the groove width of the PCB motherboard core board is 4-8 mil larger than the width of the PCB sub-board ensures that the PCB sub-board can be completely placed in the embedding groove, while controlling the displacement of the sub-board, improving the accuracy of the embedding position, and ensuring the fullness of the resin filling the gaps after lamination; The design of the prepreg groove width being 10-14 mil wider than the PCB sub-board width ensures effective spacing for prepreg resin filling during lamination, while also solving the problem of prepreg misalignment and deformation leading to dimensional deviations in the embedded grooves. The design of the embedded groove depth being 0-0.05 mm greater than the PCB sub-board thickness allows for sufficient space during PCB lamination. After lamination, the prepreg thickness changes, but under pressure, it remains equal to the sub-board thickness, ensuring a flat board surface. Compared to existing technologies, this embodiment's embedded groove implementation effectively matches the PCB sub-board thickness, preventing unevenness of the PCB core board due to excessively thick or thin sub-boards and ensuring bonding failure due to localized pressure. It should be noted that in this embodiment, step S20 employs a "layered pre-grooving" strategy to construct the embedded groove, rather than performing integral grooves on the laminated thick plate. This method effectively avoids problems such as decreased precision, material stress concentration, and excessive tool wear caused by deep groove processing. Independent pre-processing of each core board and prepreg layer ensures the precision of each groove position, resulting in extremely high verticality and dimensional consistency of the groove sidewalls after stacking. The differentiated groove width design incorporates profound material mechanics and fluid dynamics considerations: the core board groove width provides a tight-fitting positioning space. This design not only limits excessive displacement of the prepreg board within the plane, ensuring alignment accuracy, but also provides just the right amount of capillary channels for the resin. The width of the prepreg groove is designed to account for the melting, flowing, and curing shrinkage of the prepreg during lamination. The larger space provides a buffer for its flow, compensating for its inherent dimensional instability and potential interlayer misalignment. This ensures that even with some deviation, sufficient molten resin can still coat the sidewalls of the prepreg board and fill all gaps. In addition, the controlled groove depth ensures the flatness of the board surface. This small positive tolerance provides the necessary tolerance space for the lamination process. Under high temperature and pressure, the prepreg resin flows and compresses. This design ensures that after the pressure is fully applied, the surface of the prepreg board can achieve perfect coplanarity with the surrounding motherboard surface, avoiding subsequent circuit fabrication defects or mounting problems caused by local protrusions or depressions. S30, the PCB sub-board and the pre-grooved composite substrate are stacked, so that the PCB sub-board is housed in the embedded groove, and then pressed together, so that the PCB sub-board, the prepreg and the PCB motherboard core board are integrated into one, and the extended edge of the PCB sub-board protrudes beyond the edge of the composite board formed after pressing. It should be noted that after the PCB board is pressed, the embedded PCB sub-board needs to undergo further processes such as drilling, hole metallization, outer layer circuit fabrication, assembly soldering and surface treatment. This process is a routine process in PCB manufacturing and will not be described in detail here. It should be noted that step S30 is a crucial molding process for achieving the integration of the mother and daughter boards. During lamination, a high-precision alignment system is required to accurately place the PCB daughter board into the groove of the composite substrate. The subsequent pressing process requires precise control of temperature, pressure, and time. Under hot pressing, the prepreg undergoes four stages: melting, flowing, wetting, and curing. Driven by pressure, the molten resin not only fills all the pre-set gaps between the daughter board and the groove wall but also overflows slightly along the extended edges of the daughter board. This flow process effectively eliminates air between interfaces, ensuring a tight bond. After the resin cures, the daughter board, prepreg, and mother core board are firmly bonded together; the extended edges of the daughter board are completely encapsulated by the resin during this process, preparing for final cutting and sealing. The integrated board after pressing is ready for subsequent standard PCB processing. S40, the edge of the laminated assembly board is cut according to the designed edge line to form a finished PCB board with an edge embedding structure; specifically, after the PCB sub-board surface treatment is completed, it must be cut along the designed edge line by a CNC milling machine, and the area extending about 1.0mm from the embedding area will also be removed to obtain a finished PCB board with an edge embedding structure.
[0018] It should be noted that step S40 is the final, crucial step in achieving a high-reliability edge-embedded structure. After completing all standard processes such as inner and outer layer circuitry, solder masking, and surface treatment, a high-performance CNC milling machine is used to route the cutting based on the precise shape data of the final product. The cutting path will precisely pass through the 1.0mm area extending from the sub-board. This cutting process forms the final product shape and provides a "final seal" for the embedded interface. It removes any tiny resin flow end defects or stress concentration areas that may exist in the sub-board extension area and its surroundings, exposing a completely new, smooth board edge cross-section that is fully and densely wrapped and filled with resin from the inside out. The sub-board material and the motherboard material on this cross-section achieve a seamless and strong molecular-level bond through the resin layer, fundamentally eliminating the delamination initiation points that are prone to occur in traditional edge-embedded structures.
[0019] It should be noted that, in this embodiment, the edge-embedded PCB manufacturing method designs at least one edge of the PCB sub-board to extend outward beyond the corresponding edge of the finished PCB, and performs edge line cutting after lamination to ensure that the resin at the interface between the PCB sub-board and the PCB motherboard core board is full, thus structurally eliminating voids at the board edge. By pre-grooving grooves on the composite substrate consisting of multi-layer PCB motherboard core boards and prepregs stacked alternately, corresponding to the embedding position of the PCB sub-board, embedding grooves are formed, which can provide a preliminary positioning reference for the embedding of the PCB sub-board. The depth of the embedding grooves can be adaptively adjusted with the thickness of the PCB sub-board to ensure the flatness of the finished PCB board surface after lamination. Therefore, the present invention can solve the problems in the prior art where resin voids occur at the sub / mother board connection position when the sub-board is thicker or the embedding area is at the edge of the PCB board, leading to scrap, and where the mismatch between the depth of the motherboard groove and the thickness of the sub-board leads to uneven board surface. This improves the reliability, signal integrity, and heat dissipation performance of the PCB board, while reducing production costs and increasing yield.
[0020] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.
Claims
1. A method for manufacturing an edge-embedded PCB, characterized in that, The edge-embedded PCB manufacturing method includes: Fabricate a PCB sub-board, wherein at least one edge of the PCB sub-board is designed to extend outward beyond the corresponding edge of the finished PCB; A composite substrate consisting of a multilayer PCB motherboard core board and a prepreg stacked alternately is fabricated, and pre-grooves are made on the composite substrate corresponding to the embedding positions of the PCB sub-board to form embedding grooves. The PCB sub-board and the pre-grooved composite substrate are stacked, so that the PCB sub-board is housed in the embedded groove, and then pressed together, so that the PCB sub-board, the prepreg and the PCB motherboard core board are combined into one, and the extended edge of the PCB sub-board protrudes beyond the edge of the composite board formed after pressing. The laminated composite board is cut along the designed edge lines to form a finished PCB board with an edge embedding structure.
2. The method for manufacturing an edge-embedded PCB according to claim 1, characterized in that, The edge of the PCB sub-board extends outward by approximately 1.0 mm.
3. The method for manufacturing an edge-embedded PCB according to claim 1, characterized in that, During the process of pre-grooving the PCB sub-board at the embedded position on the combined substrate, the PCB motherboard core board and the prepreg corresponding to the embedded position of the PCB sub-board need to be pre-grooved respectively.
4. The method for manufacturing an edge-embedded PCB according to claim 3, characterized in that, The width of the grooves on the PCB motherboard core board is 4-8 mil wider than the width of the PCB daughterboard.
5. The method for manufacturing an edge-embedded PCB according to claim 3, characterized in that, The groove width of the prepreg is 10-14 mil wider than the width of the PCB sub-board.
6. The method for manufacturing an edge-mounted PCB according to claim 1, characterized in that, The depth of the embedded groove is 0-0.05mm greater than the thickness of the PCB sub-board.
7. The method for manufacturing an edge-embedded PCB according to claim 1, characterized in that, The method for manufacturing the PCB sub-board is as follows: Cut the copper-clad laminate into PCB sub-board substrates according to the design dimensions, and etch the PCB sub-board circuit pattern on one side of the PCB sub-board substrate; The PCB sub-board circuit pattern is cut according to the design shape to form the PCB sub-board.
8. The method for manufacturing an edge-embedded PCB according to claim 1, characterized in that, The method for manufacturing the composite substrate includes: Cut multiple PCB motherboard cores from copper-clad laminate according to the design dimensions, etch PCB motherboard core circuit patterns on one side of each PCB motherboard core, and cut multiple prepreg sheets of the same size as the PCB motherboard cores. Pre-grooving is performed on the PCB motherboard core board and prepreg according to the design dimensions; The PCB motherboard core board and the prepreg are stacked in an alternating manner to form a composite substrate.