Copper clad frame combination for improving flatness of total pressing manufacturing of high multi-layer printed circuit board

Abstract

The utility model provides a kind of to improve the flatness of copper-clad frame combination of high multilayer printed circuit board total pressure making, in total pressure process, by being configured with different plate edge patterns for adjacent pressure sub-plate, specifically, by in the pressure sub-plate plate edge with different sub-plate thickness and / or copper thickness respectively corresponding setting plate edge pattern with different glue channel, to carry out the differentiating stress control and glue guiding cooperation between different pressure sub-plate, simultaneously, the structural rigidity of the edge of different pressure sub-plate in pressure laminated plate structure and resin dredging efficiency are improved, to directionally enhance the overall deformation resistance of relatively thin pressure sub-plate, simultaneously directionally improve the internal stress release effect of relatively thick pressure sub-plate, to significantly improve the interlayer bonding uniformity and overall flatness of high multilayer printed circuit board total pressure process.

Description

Technical Field

[0001] This utility model relates to the field of electronic manufacturing technology, specifically to a copper-clad frame assembly for improving the flatness of the overall lamination process of multilayer printed circuit boards. Background Technology

[0002] With the continuous advancement of printed circuit board (PCB) technology, especially in demanding fields such as 5G communication, artificial intelligence servers, and autonomous driving radar, PCBs are evolving towards smaller size, higher integration, and stronger performance. To achieve high-speed signal transmission, high-power supply, and integration of different dielectric properties within a limited space, designs often employ methods such as increasing the number of circuit board layers, dividing the board into different functional areas, and using a mix of substrates. While these methods significantly improve the integration and design flexibility of PCBs, meeting the requirements of high-end applications for signal quality, power stability, and thermal management, they also pose significant challenges to the manufacturing of multilayer PCBs, particularly the process of laminating multiple sub-boards, in terms of the precision and reliability of the final product.

[0003] Specifically, to achieve the diverse functions of high-multilayer PCBs, the sub-boards often require different types and thicknesses of substrates, and their surface circuit designs also vary. For example, high-speed signal layers tend to use thin copper substrates to reduce losses, while power layers require thick copper substrates to carry large currents. Simultaneously, the distribution of circuit patterns across layers according to functional requirements results in uneven copper density distribution within and between sub-boards. During thermoforming, differences in copper thickness and density on the sub-boards cause an imbalance in thermal stress distribution, leading to inconsistent thickness and bending deformation after lamination. Furthermore, in the multiple lamination processes of high-multilayer PCBs, the asymmetrical overall structure and the differences in stiffness and coefficient of thermal expansion between different substrates, thicknesses, and copper thicknesses exacerbate the uneven distribution of thermal stress. In addition, the heating and cooling rates of sub-boards of different thicknesses are not synchronized during lamination, and the cumulative bending effect from multiple laminations further increases the risk of interlayer deformation, threatening the precision and reliability of the final product. Therefore, a technical solution is needed to address the situation where multiple laminated circuit boards in a multilayer PCB have different copper thicknesses and board thicknesses, and to effectively solve the problems of lamination uniformity and board bending. Utility Model Content

[0004] The present invention aims to overcome at least one of the defects of the prior art and provide a copper-clad frame assembly that improves the flatness of the overall lamination of multilayer printed circuit boards.

[0005] To solve the above technical problems, this utility model provides a copper-clad frame assembly to improve the flatness of the overall lamination of high-multilayer printed circuit boards. The high-multilayer printed circuit board is formed by laminating multiple lamination sub-boards through an adhesive layer. Each lamination sub-board has a different sub-board thickness and / or surface copper thickness. Before the final pressing, multiple pressing sub-plates and adhesive layers are stacked according to the design requirements to form a pressing stacked plate structure. Each of the laminated sub-boards is surrounded by a rectangular copper-clad border, and the copper-clad borders together form a copper-clad border combination according to the stacking order of the laminated stacked board structure. In the copper-clad frame assembly, the upper surface of the copper-clad frame of each lamination sub-board is provided with a corresponding edge pattern, and the edge patterns of adjacent lamination sub-boards are different from each other. Several adhesive flow grooves are provided on the edge pattern of the board. The adhesive flow grooves extend from the inside of the copper-clad frame to the outside and are used to guide the interlayer adhesive flow between the various laminated sub-boards during the overall lamination process. The plate edge pattern includes at least a first plate edge pattern with a diverging glue flow groove, and / or a second plate edge pattern with a petal-shaped glue flow groove; The edge pattern of the board and the outer circuit pattern of its corresponding press-fit sub-board are manufactured simultaneously.

[0006] In this technical solution, during the overall lamination process, by configuring different edge patterns for adjacent lamination sub-boards, specifically by setting different flow groove patterns for the edges of lamination sub-boards with different thicknesses and / or copper thicknesses, differentiated stress control and flow guidance are achieved between different lamination sub-boards. This also improves the structural rigidity and resin conduction efficiency of the edges of different lamination sub-boards in the lamination stack structure, thereby directionally enhancing the overall deformation resistance of thinner lamination sub-boards and directionally improving the internal stress release effect of thicker lamination sub-boards. This significantly improves the interlayer bonding uniformity and overall flatness of the high-multilayer printed circuit board in the overall lamination process. Specifically, by configuring different edge patterns for adjacent laminated sub-boards, including at least one or more edge patterns with a divergent glue flow channel or a petal-shaped glue flow channel, the individual stress adaptability of laminated sub-boards with different characteristics during the lamination process is adjusted by selecting and matching the glue flow channels: enhancing rigidity for thinner laminated sub-boards and enhancing stress release for thicker laminated sub-boards, while improving pattern alignment accuracy and interlayer resin flow uniformity, thereby significantly enhancing the overall flatness and bonding reliability of the high-multilayer printed circuit board overall lamination.

[0007] Furthermore, the upper and lower copper-clad frames of the laminating sub-board are provided with identical glue-flowing grooves, and the positions of the glue-flowing grooves on the upper and lower surfaces of each laminating sub-board are staggered. By setting identical glue-flowing grooves with staggered positions on the upper and lower copper-clad frames of each laminating sub-board, the glue-flowing channels are evenly distributed throughout the entire laminating sub-board during the overall lamination process, thus discretizing the stress path of the entire board. The staggered layout of the glue-flowing grooves on the upper and lower surfaces avoids stress concentration, thereby improving the structural integrity and anti-delamination ability of the laminating sub-board in the thickness direction. At the same time, it improves the three-dimensional flow uniformity and filling efficiency of the resin between layers, thereby significantly enhancing the density, flatness, and overall manufacturing reliability of the interface bonding between each laminating sub-board during the lamination process.

[0008] Furthermore, the divergent adhesive flow channel is linear and radially distributed from the inner side to the outer side of the copper-clad frame; The petal-shaped adhesive channel divides the copper-clad frame into an array of petal-shaped copper sheet structures. The petal-shaped copper sheet structure includes a circular copper sheet and several elliptical copper sheets that are inclined and surround the circular copper sheet, and there are gaps between the circular copper sheet and the elliptical copper sheet.

[0009] In this technical solution, by employing linear adhesive flow channels radially distributed from the inside to the outside of the copper-clad frame, a large continuous copper surface is retained on the board edge pattern. This improves the rigidity of the laminated sub-board edge and the efficiency of surface resin directional conduction during lamination, and enhances its resistance to lamination deformation. Simultaneously, by dividing the copper-clad frame into a petal-shaped structure consisting of circular copper sheets and gaps around elliptical copper sheets, the uniformity of copper surface dispersion on the board edge pattern is improved while constructing effective adhesive flow channels. This allows for the uniform and sufficient release of internal stress through the gaps in the petal structure, greatly reducing the pulling effect on the overall structure. This synergistically improves the flatness and bonding reliability of the lamination process.

[0010] Furthermore, the press-fit sub-board includes at least a first circuit board and a second circuit board, and the surface copper thickness and overall sub-board thickness of the first circuit board are both smaller than those of the second circuit board; In the copper-clad border assembly, the copper-clad border of the first circuit board adopts a first board edge pattern with a diverging glue flow groove, and the copper-clad border of the second circuit board adopts a second board edge pattern with a petal-shaped glue flow groove. The width of the edge pattern on the copper-clad frame of both the first and second circuit boards is not less than 1.5 inches.

[0011] In this technical solution, by using a wider copper-clad frame, preferably with the width of the board edge pattern on the copper-clad frame not less than 1.5 inches, the stress imbalance caused by the difference in copper density and board thickness on the laminating sub-boards is balanced. Furthermore, by configuring radially divergent glue flow grooves for the thinner first circuit board and petal-shaped glue flow grooves for the thicker second circuit board, the overall rigidity of the thin board edge area and its ability to resist lamination deformation are improved. At the same time, the efficiency of the thick board in releasing internal stress through the petal structure is improved, thereby significantly enhancing the deformation coordination and overall flatness during the lamination of heterogeneous sub-boards in the overall lamination process of high-multilayer circuit boards.

[0012] Furthermore, the width of the divergent adhesive flow channel is 0.5-1.5mm, and when the divergent adhesive flow channel is used, 10-25 adhesive flow channels are set on each copper-clad frame; thereby ensuring that the opened adhesive flow channels improve the resin guiding efficiency during the pressing process, while the layout design of the large area copper sheet ensures the structural continuity of the copper-clad frame and strengthens the bending stiffness of the thin plate.

[0013] Furthermore, in the petal-shaped copper sheet structure, the diameter of the circular copper sheet is 0.8-1.2mm, the long side of the elliptical copper sheet is 3.2-4.8mm, the short side is 1.6-2.4mm, and the gap between the circular copper sheet and the adjacent elliptical copper sheet, as well as the gap between adjacent petal-shaped copper sheet structures, is 0.4-0.6mm; when using the petal-shaped adhesive groove, each copper-clad frame is provided with no less than one row of petal-shaped copper sheet structures. By adjusting the size of each unit in the petal-shaped copper sheet structure and maintaining a gap of 0.4-0.6mm, a uniform stress buffer network is constructed around the edge of the circuit board by forming a flow channel. The regular arrangement of the petal units provides a good foundation for the uniformity of stress release within the circuit board. At the same time, by controlling the size gap of each unit in the petal-shaped copper sheet structure, a multi-directional and uniform flow channel is formed, thereby efficiently releasing the thermal stress accumulated in thicker circuit boards and improving the ability to suppress deformation during lamination and reliability. Furthermore, by ensuring that there is at least one row of petal-shaped copper sheet structures on each side of the circuit board, full coverage is guaranteed on the sub-board circuit board, thereby guiding the resin flow more uniformly and efficiently during the lamination process and ensuring the consistency of stress relief across the entire circuit board.

[0014] Furthermore, the second edge pattern of the second circuit board is designed in stages based on the surface copper thickness of the second circuit board and the thickness difference between the first circuit board and the second circuit board: When the surface copper thickness of the second circuit board is no greater than 2oz, or the thickness difference between the first circuit board and the second circuit board is less than 25mil, a divergent glue flow groove is provided in the area 0.8 inches inward from the outer edge of the second board edge pattern, and a petal-shaped glue flow groove is provided in the remaining areas of the board edge pattern. When the surface copper thickness of the second circuit board is greater than 2oz and the thickness difference between the first circuit board and the second circuit board is not less than 25mil, petal-shaped glue flow grooves are provided in the graphic area of ​​the board edge.

[0015] In this technical solution, the edge pattern on the copper-clad frame is designed in a hierarchical manner based on the copper thickness of the thick sub-board (i.e., the second circuit board) and the thickness difference between it and the thin sub-board (i.e., the first circuit board). This allows the edge pattern of the copper-clad structure on the edge of the circuit board to better match the impact of the thickness difference between the first and second circuit boards on the internal stress release state during the lamination process of the multilayer printed circuit board, while ensuring the structural rigidity of the circuit board. This minimizes the deformation of the sub-boards in the multilayer printed circuit board and ensures the overall lamination flatness of the multilayer printed circuit board. Specifically, based on the overall use of radial flow channels in the copper-clad structure of the first circuit board, when the copper thickness of the second circuit board is no more than 2oz or the thickness difference between the first and second circuit boards is less than 25mil, radial flow channels are used in the 0.8-inch area on the outer edge of the second circuit board. By using a continuous copper surface on the outer edge to strengthen the support for the overall structural rigidity of the second circuit board, and petal-shaped flow channels are used in the inner area to guide and enhance the flow of adhesive on the board surface, thereby better releasing the internal stress generated on the circuit board during the lamination process and avoiding deformation of the circuit board. When the copper thickness of the second circuit board is greater than 2oz and the thickness difference between the first and second circuit boards is no less than 25mil, petal-shaped flow channels are used in the entire area of ​​the copper-clad frame on the edge of the second circuit board, thereby maximizing the flow speed of adhesive on the board surface and completely eliminating the internal stress generated on the circuit board during lamination.

[0016] Furthermore, the second plate edge pattern features a divergent adhesive flow channel within a 0.8-inch inward region from the outer edge of the plate edge, while petal-shaped adhesive flow channels are provided in the remaining plate edge pattern regions; the divergent adhesive flow channel is connected to its adjacent petal-shaped adhesive flow channel. By employing a mixed design of straight and petal-shaped adhesive flow channels on the plate edge pattern of the thicker sub-plate, the rigidity support of key areas of the plate edge is improved to stabilize the shape. At the same time, the interconnected adhesive flow channels enable the smooth dissipation of internal stress from the inside out, thereby improving the stress concentration problem caused by abrupt changes in stiffness during the pressing process and enhancing the deformation coordination and dimensional stability of the overall structure.

[0017] Furthermore, in both the first and second circuit boards, the radial flow channels on the upper and lower surfaces are staggered. In the second circuit board, the petal-shaped copper sheet structures on the upper and lower surfaces are of the same size, with the circular copper sheets aligned and the elliptical copper sheets surrounding the circular copper sheets in opposite directions. In the first circuit board with radial flow channels on the board edge, by staggering the radial flow channels on the upper and lower surfaces of the circuit board, the staggered flow directions are guided on different surfaces of the same circuit board. This allows the internal stress to be released evenly on the board surface during hot pressing, avoiding overlapping stress transmission paths and stress concentration that could cause board surface deformation. At the same time, the staggered flow channels also ensure the uniform strength of the edge of the first circuit board, enhancing the overall deformation resistance of the relatively thin first circuit board. In the second circuit board with a petal-shaped glue channel on the edge, the use of a petal-shaped copper sheet structure with aligned circular copper sheets and elliptical copper sheets rotating in opposite directions on the upper and lower surfaces improves the uniformity of internal stress release on the board surface during hot pressing, avoiding stress concentration that could cause board surface deformation. Simultaneously, due to the thicker copper surface on the second circuit board and the dispersed copper surface formed by the petal-shaped copper sheet structure, the opposite rotation of the petal-shaped copper sheets on the upper and lower surfaces can generate stresses in opposite directions during hot pressing based on the difference in thermal expansion coefficients between the copper foil and the substrate. This forms a self-balancing constraint network on the upper and lower surfaces of the second circuit board, flattening the entire board surface and effectively resisting local deformation. This further improves the flatness of the second circuit board during pressing and simultaneously enhances the uniformity of interlayer glue filling and the reliability of interlayer bonding.

[0018] Another objective of this utility model is to provide a high multilayer printed circuit board. In the overall lamination process, the high multilayer printed circuit board adopts the copper-clad frame combination provided in this technical solution in the lamination stack structure. The lamination stack structure is laminated according to the design, and then the copper-clad frame combination is removed from the laminated board to obtain the high multilayer printed circuit board.

[0019] The beneficial effects of this utility model are as follows: 1. A copper-clad frame assembly is provided to improve the flatness of the overall lamination process of high-multilayer printed circuit boards. During the overall lamination process, different edge patterns are configured for adjacent lamination sub-boards. Specifically, edge patterns with different flow grooves are set for the edges of lamination sub-boards with different sub-board thicknesses and / or copper thicknesses, thereby achieving differentiated stress control and flow guidance between different lamination sub-boards. At the same time, the structural rigidity and resin conduction efficiency of the edges of different lamination sub-boards in the lamination stack structure are improved, thereby directionally enhancing the overall deformation resistance of thinner lamination sub-boards and directionally improving the internal stress release effect of thicker lamination sub-boards. This significantly improves the interlayer bonding uniformity and overall flatness of the overall lamination process of high-multilayer printed circuit boards. Specifically, by configuring different edge patterns for adjacent laminated sub-boards, including at least one or more edge patterns with a divergent glue flow channel or a petal-shaped glue flow channel, the individual stress adaptability of laminated sub-boards with different characteristics during the lamination process is adjusted by selecting and matching the glue flow channels: enhancing rigidity for thinner laminated sub-boards and enhancing stress release for thicker laminated sub-boards, while improving pattern alignment accuracy and interlayer resin flow uniformity, thereby significantly enhancing the overall flatness and bonding reliability of the high-multilayer printed circuit board overall lamination. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the high-multilayer printed circuit board lamination stack structure provided by this utility model.

[0021] Figure 2 This is a partial structural diagram of the first board edge pattern with a diverging adhesive groove in the copper-clad frame assembly provided by this utility model.

[0022] Figure 3 This is a partial structural diagram of the second plate edge pattern with a petal-shaped glue channel in the copper-clad frame assembly provided by this utility model.

[0023] Figure 4 This is a partial structural diagram of the copper-clad border assembly provided in Example 2.

[0024] Figure 5 This is a partial structural diagram of the copper-clad frame assembly provided in Example 2, in which a divergent adhesive flow groove is provided in the area 0.8 inches inward from the outer edge of the second board edge pattern, and a petal-shaped adhesive flow groove is provided in the remaining areas of the board edge pattern.

[0025] Figure 6 This is a partial structural diagram of the second board edge pattern on the upper and lower surfaces of the second circuit board in the copper-clad frame assembly provided in Embodiment 2, in which a petal-shaped glue channel is opened.

[0026] Reference numerals in the attached diagram: 1. Press-laminated stacked board structure; 100. High multilayer printed circuit board; 110. First circuit board; 120. Second circuit board; 200. Copper-clad frame assembly; 201. First board edge pattern; 202. Second board edge pattern; 210. Flow groove; 211. Diverging flow groove; 212. Petal-shaped flow groove. Detailed Implementation

[0027] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this invention. To better illustrate the following embodiments, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0028] Example 1 like Figures 1-3 As shown, this embodiment provides a copper-clad frame assembly to improve the flatness of the overall lamination fabrication of a high-multilayer printed circuit board. The high-multilayer printed circuit board 100 is formed by laminating multiple lamination sub-boards through an adhesive layer. Each lamination sub-board has a different sub-board thickness and / or surface copper thickness. Before the final pressing, multiple pressing sub-plates and adhesive layers are stacked according to the design requirements to form a pressing stack structure 1; Each laminated sub-board is surrounded by a rectangular copper-clad border, and the copper-clad borders together form a copper-clad border assembly 200 according to the stacking order of the laminated stacked board structure 1. In the copper-clad frame assembly 200, the upper surface of the copper-clad frame of each lamination sub-board is provided with a corresponding board edge pattern, and the board edge patterns corresponding to adjacent lamination sub-boards are different from each other. Several adhesive flow grooves 210 are provided on the edge pattern of the board. The adhesive flow grooves 210 extend from the inside of the copper-clad frame to the outside and are used to guide the interlayer adhesive flow between the various laminated sub-boards during the overall lamination process. The edge pattern includes at least a first edge pattern 201 with a diverging glue channel 211, and / or a second edge pattern 202 with a petal-shaped glue channel 212; The edge pattern of the board and the outer circuit pattern of its corresponding press-fit sub-board are manufactured simultaneously.

[0029] Specifically, by configuring different edge patterns for adjacent lamination sub-boards, and specifically by setting different flow grooves 210 on the edges of lamination sub-boards with different thicknesses and / or copper thicknesses, including at least one or more of the first edge pattern 201 with a divergent flow groove 211 or a petal-shaped flow groove 212, differentiated stress control and flow guidance are achieved between lamination sub-boards with different thicknesses and / or copper thicknesses. This allows for adjustments to the individual stress adaptability of lamination sub-boards with different characteristics during the lamination process through the selection and matching of the flow grooves 210: enhancing rigidity for thinner lamination sub-boards and enhancing stress release for thicker lamination sub-boards, while improving pattern alignment accuracy and interlayer resin flow uniformity, thereby significantly enhancing the overall flatness and bonding reliability of the high-multilayer printed circuit board lamination.

[0030] Furthermore, both the upper and lower copper-clad borders of the laminating sub-board are provided with identical glue-flowing grooves 210, and the positions of the glue-flowing grooves 210 on the upper and lower sides of each laminating sub-board are staggered. Specifically, by setting identical glue-flowing grooves 210 in staggered positions on the upper and lower copper-clad borders of each laminating sub-board, the path of stress on the entire board is discretized by uniformly dispersing the glue-flowing channels on the entire board during the overall lamination process. The staggered layout of the glue-flowing grooves 210 on the upper and lower sides avoids stress concentration, thereby improving the structural integrity and anti-delamination ability of the laminating sub-board in the thickness direction. At the same time, it improves the three-dimensional flow uniformity and filling efficiency of the resin between layers, thus significantly enhancing the density, flatness and overall manufacturing reliability of the interface bonding between each laminating sub-board during the lamination process.

[0031] Furthermore, the divergent adhesive flow channel 211 is linear and radially distributed from the inner side of the copper-clad frame to the outer side; The petal-shaped adhesive flow channel 212 divides the copper-clad frame into an array of petal-shaped copper sheet structures. The petal-shaped copper sheet structures include circular copper sheets and several elliptical copper sheets that are inclined and surround the circular copper sheets, and there are gaps between the circular copper sheets and the elliptical copper sheets.

[0032] Specifically, by employing linear adhesive flow channels radiating from the inside to the outside of the copper-clad frame, a larger continuous copper surface is retained on the board edge pattern. This improves the rigidity of the laminated sub-board edge and the efficiency of surface resin directional flow during lamination, enhancing its resistance to lamination deformation. Simultaneously, by dividing the copper-clad frame into a petal-shaped structure consisting of circular copper sheets and gaps between elliptical copper sheets, the uniformity of copper surface dispersion on the board edge pattern is improved while constructing effective adhesive flow channels. This allows for the uniform and sufficient release of internal stress through the gaps in the petal structure, significantly reducing the pulling effect on the overall structure. Consequently, the flatness and bonding reliability of the lamination process are synergistically improved.

[0033] Example 2 like Figures 1-6 As shown, this embodiment provides a copper-clad frame assembly to improve the flatness of the overall lamination fabrication of multilayer printed circuit boards. The difference from Embodiment 1 is that the lamination sub-board includes at least a first circuit board 110 and a second circuit board 120, and the surface copper thickness and overall sub-board thickness of the first circuit board 110 are both smaller than those of the second circuit board 120. In the copper-clad border assembly 200, the copper-clad border of the first circuit board 110 adopts a first board edge pattern 201 with a diverging glue channel 211, and the copper-clad border of the second circuit board 120 adopts a second board edge pattern 202 with a petal-shaped glue channel 212. The width of the edge graphics on the copper-clad frame of both the first circuit board 110 and the second circuit board 120 is not less than 1.5 inches.

[0034] Specifically, by using a wider copper-clad border on the lamination sub-board, preferably with the width of the board edge pattern on the copper-clad border not less than 1.5 inches, the stress imbalance caused by the difference in copper density and board thickness on the lamination sub-board is balanced. Furthermore, by configuring radially divergent glue flow grooves 211 for the thinner first circuit board 110 and petal-shaped glue flow grooves 212 for the thicker second circuit board 120, the overall rigidity of the thin board edge area and its ability to resist lamination deformation are improved, while the efficiency of the thick board in releasing internal stress through the petal structure is improved. Thus, the deformation coordination and overall flatness during the lamination of heterogeneous sub-boards are significantly enhanced in the overall lamination process of high-multilayer circuit boards.

[0035] Preferably, the width of the divergent glue flow channel 211 is 0.5-1.5mm, and when the divergent glue flow channel 211 is used, 10-25 glue flow channels 210 are set on each copper-clad frame; thereby ensuring that the opened glue flow channels 210 improve the resin guiding efficiency during the pressing process, while the layout design of the large area copper sheet ensures the structural continuity of the copper-clad frame and strengthens the bending stiffness of the thin plate.

[0036] Preferably, in the petal-shaped copper sheet structure, the diameter of the circular copper sheet is 0.8-1.2mm, the long side of the elliptical copper sheet is 3.2-4.8mm, the short side is 1.6-2.4mm, and the gap between the circular copper sheet and the adjacent elliptical copper sheet, and the gap between the adjacent petal-shaped copper sheet structures are all 0.4-0.6mm; when using the petal-shaped glue channel 212, the petal-shaped copper sheet structure is set on each copper-clad frame in at least one row. By adjusting the size of each unit in the petal-shaped copper sheet structure and maintaining a gap of 0.4-0.6mm, a flow groove 210 is formed and arranged around the edge of the circuit board to construct a uniform stress buffer network. The regular arrangement of the petal units provides a good foundation for the uniformity of stress release within the circuit board. At the same time, by controlling the size gap of each unit in the petal-shaped copper sheet structure to form a multi-directional and uniform flow groove 210, the thermal stress accumulated in the thicker circuit board can be released efficiently, improving the ability to suppress deformation during lamination and enhancing reliability. Furthermore, by ensuring that there is at least one row of petal-shaped copper sheet structures on each side of the circuit board, full coverage is achieved on the sub-board circuit board, thereby guiding the resin flow more uniformly and efficiently during the lamination process and ensuring the consistency of stress relief across the entire circuit board.

[0037] Furthermore, the second edge pattern 202 of the second circuit board 120 is designed in stages based on the surface copper thickness of the second circuit board 120 and the thickness difference between the first circuit board 110 and the second circuit board 120: When the surface copper thickness of the second circuit board 120 is not greater than 2oz, or the thickness difference between the first circuit board 110 and the second circuit board 120 is less than 25mil, the second board edge pattern 202 is provided with a divergent glue channel 211 in the area 0.8inch inward from the outer edge of the board edge, and a petal-shaped glue channel 212 is provided in the remaining board edge pattern area. When the surface copper thickness of the second circuit board 120 is greater than 2oz and the thickness difference between the first circuit board 110 and the second circuit board 120 is not less than 25mil, a petal-shaped glue channel 212 is provided in the edge graphic area.

[0038] Specifically, for the board edge pattern on the copper-clad frame, the board edge pattern is designed in a hierarchical manner according to the copper thickness of the thick sub-board, i.e., the second circuit board 120, and the thickness difference with the thin sub-board, i.e., the first circuit board 110. This allows the board edge pattern of the copper-clad structure set at the edge of the circuit board to better match the impact of the board thickness difference and copper thickness difference between the first circuit board 110 and the second circuit board 120 on the internal stress release state during the lamination process of the multilayer printed circuit board 100, while ensuring the structural rigidity of the circuit board. This minimizes the deformation of the sub-board in the multilayer printed circuit board 100 and ensures the overall lamination flatness of the multilayer printed circuit board 100. Specifically, based on the overall use of radial flow grooves 210 in the copper-clad structure of the first circuit board 110, when the copper thickness of the second circuit board 120 is no greater than 2oz or the thickness difference between the first circuit board 110 and the second circuit board 120 is less than 25mil, radial flow grooves 210 are used in the 0.8-inch area of ​​the outer edge of the second circuit board 120. By using a continuous copper surface at the outer edge to strengthen the support for the overall structural rigidity of the second circuit board 120, and at the same time using petal-shaped flow grooves 212 in the inner area to guide and enhance the flow of adhesive on the board surface, the internal stress generated on the circuit board during the lamination process is better released, thus avoiding deformation of the circuit board. When the copper thickness of the second circuit board 120 is greater than 2oz and the thickness difference between the first circuit board 110 and the second circuit board 120 is no less than 25mil, petal-shaped flow grooves 212 are used in the entire area of ​​the copper-clad frame of the second circuit board 120, thereby maximizing the flow speed of adhesive on the board surface and completely eliminating the internal stress generated on the circuit board during lamination.

[0039] Furthermore, when the second plate edge pattern 202 has a divergent glue channel 211 in a region 0.8 inches inward from the outer edge of the plate edge, and petal-shaped glue channels 212 in the remaining plate edge pattern regions, the divergent glue channel 211 is connected to its adjacent petal-shaped glue channel 212. By adopting a mixed design of straight glue channels 210 and petal-shaped glue channels 212 on the plate edge pattern of the thicker sub-plate, the rigidity support of the key area of ​​the plate edge is improved to stabilize the shape. At the same time, the glue channels 210 that are connected inside and outside realize the smooth dissipation of internal stress from the inside to the outside, thereby improving the stress concentration problem caused by the sudden change in stiffness during the pressing process and enhancing the deformation coordination and dimensional stability of the overall structure.

[0040] Furthermore, in the first circuit board 110 and the second circuit board 120, the divergent adhesive grooves 211 on the upper and lower surfaces are staggered; in the second circuit board 120, the petal-shaped copper sheet structures on the upper and lower surfaces are of the same size, and the circular copper sheets are aligned, while the elliptical copper sheets surround the circular copper sheets in opposite directions.

[0041] Specifically, in the first circuit board 110 with radial glue flow grooves 210 on the edge, by staggering the radial glue flow grooves 210 on the upper and lower surfaces of the circuit board, the interlaced glue flow directions are guided on different surfaces of the same circuit board. This allows the internal stress to be released evenly on the board surface during hot pressing, avoiding overlapping stress transmission paths and stress concentration that could cause board surface deformation. At the same time, the interlaced glue flow grooves 210 also ensure the uniform strength of the edge of the first circuit board 110, enhancing the overall deformation resistance of the thinner first circuit board 110. In the second circuit board 120, which uses a petal-shaped glue channel 212 for the edge pattern, the uniformity of internal stress release on the board surface during hot pressing is improved by using a petal-shaped copper sheet structure with circular copper sheets aligned and elliptical copper sheets rotating in opposite directions on the upper and lower surfaces of the circuit board. This avoids stress concentration that could cause board surface deformation. At the same time, since the copper surface on the second circuit board 120 is thicker and the copper surface formed by the petal-shaped copper sheet structure is dispersed, the petal-shaped copper sheet structure with opposite rotation directions on the upper and lower surfaces can generate stresses in opposite directions during hot pressing based on the difference in thermal expansion coefficients between the copper foil and the substrate. This forms a self-balancing constraint network on the upper and lower surfaces of the second circuit board 120, flattening the entire board surface and effectively resisting local deformation on the board. This further improves the flatness of the second circuit board 120 during pressing and also improves the uniformity of interlayer glue filling and the reliability of interlayer bonding.

[0042] Example 3 This embodiment provides a high multilayer printed circuit board. In this high multilayer printed circuit board, a copper-clad border combination 200 as provided in any one of embodiments 1-2 is used to form a laminated stack structure 1. The laminated stack structure is laminated according to the design, and then the copper-clad border combination is removed from the laminated board to obtain the obtained high multilayer printed circuit board.

[0043] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A copper-clad frame assembly for improving the flatness of the overall lamination fabrication of multilayer printed circuit boards, characterized in that: The high-multilayer printed circuit board is formed by laminating multiple laminated sub-boards together with an adhesive layer. Each laminated sub-board has a different sub-board thickness and / or surface copper thickness. Before the final pressing, multiple pressing sub-plates and adhesive layers are stacked according to the design requirements to form a pressing stacked plate structure. Each of the laminated sub-boards is surrounded by a rectangular copper-clad border, and the copper-clad borders together form a copper-clad border combination according to the stacking order of the laminated stacked board structure. In the copper-clad frame assembly, each copper-clad frame has a corresponding board edge pattern on its upper surface. Several adhesive flow grooves are opened on the board edge pattern. The adhesive flow grooves extend from the inner side of the copper-clad frame to the outer side and are used to guide the interlayer adhesive flow between each laminated sub-board during the overall lamination process. The plate edge pattern includes at least a first plate edge pattern with a diverging glue flow groove and a second plate edge pattern with a petal-shaped glue flow groove; The edge pattern of the board and the outer circuit pattern of its corresponding press-fit sub-board are manufactured simultaneously.

2. The copper-clad frame assembly according to claim 1, characterized in that, The upper and lower copper-clad frames of the press-fit sub-board are provided with the same glue-flow grooves, and the glue-flow grooves on the upper and lower surfaces of each press-fit sub-board are staggered.

3. The copper-clad frame assembly according to claim 1, characterized in that, The divergent adhesive channel is linear and radially distributed from the inside to the outside of the copper-clad frame; The petal-shaped adhesive channel divides the copper-clad frame into an array of petal-shaped copper sheet structures. The petal-shaped copper sheet structure includes a circular copper sheet and several elliptical copper sheets that are inclined and surround the circular copper sheet, and there are gaps between the circular copper sheet and the elliptical copper sheet.

4. The copper-clad border assembly according to any one of claims 1-3, characterized in that, The press-fit sub-board includes at least a first circuit board and a second circuit board, and the surface copper thickness and overall sub-board thickness of the first circuit board are both smaller than those of the second circuit board. In the copper-clad border assembly, the copper-clad border of the first circuit board adopts a first board edge pattern with a diverging glue flow groove, and the copper-clad border of the second circuit board adopts a second board edge pattern with a petal-shaped glue flow groove. The width of the edge pattern on the copper-clad frame of both the first and second circuit boards is not less than 1.5 inches.

5. The copper-clad frame assembly according to claim 4, characterized in that, The width of the divergent adhesive channel is 0.5-1.5mm, and when the divergent adhesive channel is used, 10-25 adhesive channels are set on each copper-clad border.

6. The copper-clad frame assembly according to claim 3, characterized in that, In the petal-shaped copper sheet structure, the diameter of the circular copper sheet is 0.8-1.2mm, the long side of the elliptical copper sheet is 3.2-4.8mm, the short side is 1.6-2.4mm, and the gap between the circular copper sheet and the adjacent elliptical copper sheet, as well as the gap between adjacent petal-shaped copper sheet structures, is 0.4-0.6mm; when using the petal-shaped adhesive groove, each copper-clad frame shall have at least one row of petal-shaped copper sheet structures.

7. The copper-clad frame assembly according to claim 4, characterized in that, The second edge pattern of the second circuit board is designed in stages based on the surface copper thickness of the second circuit board and the thickness difference between the first and second circuit boards: When the surface copper thickness of the second circuit board is no greater than 2oz, or the thickness difference between the first circuit board and the second circuit board is less than 25mil, a divergent glue flow groove is provided in the area 0.8 inches inward from the outer edge of the second board edge pattern, and a petal-shaped glue flow groove is provided in the remaining areas of the board edge pattern. When the surface copper thickness of the second circuit board is greater than 2oz and the thickness difference between the first circuit board and the second circuit board is not less than 25mil, petal-shaped glue flow grooves are provided in the graphic area of ​​the board edge.

8. The copper-clad frame assembly according to claim 7, characterized in that, When the second board edge pattern has a divergent glue flow channel in the area 0.8 inches inward from the outer edge of the board edge, and a petal-shaped glue flow channel is set in the remaining areas of the board edge pattern; the divergent glue flow channel is connected to its adjacent petal-shaped glue flow channel.

9. The copper-clad frame assembly according to claim 7, characterized in that, In the first circuit board and the second circuit board, the divergent adhesive flow channels on the upper and lower surfaces are staggered. In the second circuit board, the petal-shaped copper sheet structures on the upper and lower surfaces are the same size, and the circular copper sheets are aligned, while the elliptical copper sheets surround the circular copper sheets in opposite directions.

10. A high-multilayer printed circuit board, characterized in that, In the overall lamination process, this high-multilayer printed circuit board adopts the copper-clad border combination provided in any one of claims 1-9 in the lamination stack structure. The lamination stack structure is laminated according to the design, and then the copper-clad border combination is removed from the laminated board to obtain the high-multilayer printed circuit board.

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