Multi-layer PCB

Abstract

The utility model provides a multi-layer PCB, and relates to the technical field of circuit board manufacturing, the multi-layer PCB comprises that each layer of PCB is provided with a heat conduction block, the heat conduction block is internally provided with a hot melting module used for heat conduction, the hot melting module occupies partial area of the heat conduction block, and projections of adjacent hot melting modules on the heat conduction block do not coincide. The hot melting modules only cover partial areas of the heat conduction blocks, and the projections of the adjacent hot melting modules on the heat conduction blocks do not coincide, so that the total thickness of the hot melting modules in the heat conduction areas is effectively reduced. By arranging the heat conduction block and the hot melting module, the heating efficiency and uniformity of the hot melt adhesive can be effectively improved, the total thickness of the hot melting module at the heat conduction block can be effectively reduced, the problems of non-uniform board thickness, buckling deformation and the like of the PCB in the hot pressing process are solved, and the production quality of the PCB is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board manufacturing, in particular to a multi-layer PCB board. Background Art

[0002] In the manufacturing process of multi-layer PCB boards, the hot pressing process is a key step to bond multiple core boards together with a hot melt adhesive to form an integral structure. The hot pressing process usually uses a hot melt block to conduct heat to heat and melt the hot melt adhesive to achieve the bonding between PCB core boards.

[0003] However, the existing hot pressing process has the following problems. Since the hot melt block melts and cools rapidly at high temperatures, it is easy to generate thermal stress, resulting in warping and deformation of the hot melt block. The warping of the hot melt block will cause the surface of the pressed PCB board to be uneven, affecting subsequent processing techniques and even leading to the scrapping of the PCB board. Due to the unreasonable shape and size design of the hot melt block, the hot melt adhesive is prone to uneven accumulation during the hot melting process, resulting in uneven board thickness of the pressed PCB board, affecting the performance and reliability of the PCB board. The hot melt adhesive has strong fluidity and is easy to form copper wrinkles around the hot melt block, affecting the line integrity and signal transmission of the PCB board.

[0004] To solve the above problems, a hot melt auxiliary structure in a PCB core board is disclosed in Chinese patent document CN218570566U, and the hot melt auxiliary structure includes a grid-shaped copper deposition area and a hot melt auxiliary structure filling pads. A hot melt module is disclosed in Chinese patent document CN219698061U, and the hot melt module includes a first hot melt part and a second hot melt part, and a gap is provided between the first hot melt part and the second hot melt part.

[0005] However, although the solutions disclosed in the above patent documents can partially solve the problems, when hot pressing, the temperature at the hot melt module is relatively high and the temperature rises quickly. Small bubbles will be generated when the PP resin at the hot melt module cures, causing excessive protrusion at the hot melt module and resulting in uneven board thickness.

[0006] Therefore, it is necessary to improve the existing multi-layer PCB board to overcome the defects of the prior art. Summary of the Utility Model

[0007] To overcome the problems existing in the related art, the purpose of the utility model is to provide a multi-layer PCB board to solve the problem of uneven board thickness caused by using a hot melt module in the prior art.

[0008] A multi-layer PCB board includes:

[0009] Each layer of the PCB board is provided with a heat-conducting block, and a hot-melt module for heat conduction is arranged in each heat-conducting block. The hot-melt module occupies a partial area of the heat-conducting block, and the projections of adjacent hot-melt modules on the heat-conducting block do not overlap.

[0010] By arranging heat-conducting blocks between each layer of the PCB board, arranging hot-melt modules in the heat-conducting blocks, and ensuring that the projections of adjacent hot-melt modules on the heat-conducting block do not overlap, heat can be effectively transferred to the hot-melt adhesive, accelerating its melting and curing process. At the same time, the total thickness of the hot-melt modules at the heat-conducting block can be effectively reduced, thereby improving the problem of uneven board thickness and enhancing the production quality of the PCB board.

[0011] Preferably, the heat-conducting block is rectangular, and the hot-melt module is distributed along the length direction or the width direction of the heat-conducting block.

[0012] Designing the heat-conducting block as rectangular and arranging the hot-melt module along the length direction or the width direction can facilitate the layout of the hot-melt module, facilitate the flow of the hot-melt adhesive, improve the uniformity of the hot-melt adhesive, reduce the phenomenon of unevenness on the surface of the PCB board after lamination, and enhance the quality and reliability of the PCB board.

[0013] Preferably, the projected area of adjacent hot-melt modules on the heat-conducting block is equal to the area of the heat-conducting block.

[0014] When the projected area of adjacent hot-melt modules on the heat-conducting block is equal to the area of the heat-conducting block, the area of the hot-melt block can be maximally increased, the heat transfer area of the hot-melt block can be improved, and the thermal lamination of the PCB board can be made more compact.

[0015] Preferably, adjacent hot-melt modules respectively extend inward along the two wide sides of the heat-conducting block.

[0016] The hot-melt module extends inward along the two wide sides of the heat-conducting block, increasing the area of the hot-melt module, thereby improving the heat conduction efficiency, accelerating the melting and curing of the hot-melt adhesive, and ultimately enhancing the production efficiency of the PCB board.

[0017] Preferably, the hot-melt module occupies half of the area of the heat-conducting block.

[0018] When the hot-melt module occupies half of the area of the heat-conducting block, the heat transfer effect and heat transfer speed between adjacent boards can be made more consistent, more effectively ensuring the consistency of the thermal lamination process.

[0019] Preferably, the heat-conducting block is arranged near the corners of the PCB board. The width of the heat-conducting block is 4 mm to 6 mm, and the length is 22 mm to 26 mm. The width of the hot-melt module is the same as the width of the heat-conducting block, and the length of the hot-melt module is equal to half of the length of the heat-conducting block.

[0020] A width range of 4 mm to 6 mm can balance the heat conduction efficiency and the uniformity of the adhesive layer. A length range of 22 mm to 26 mm can minimize the heat stress concentration and warping deformation while ensuring the hot melt efficiency. The heat conduction block is arranged near the corners of the PCB board, which can effectively reduce the phenomenon of the hot melt adhesive flowing out of the heat conduction block and ensure that the hot melt adhesive is evenly distributed within the heat conduction block, improving the quality and reliability of the PCB board after lamination.

[0021] Preferably, the thickness of the hot melt module is less than or equal to the thickness of the PCB board substrate.

[0022] The thickness of the hot melt module being less than or equal to the thickness of the PCB board substrate can effectively prevent the hot melt module from deforming during the lamination process, improving the flatness and reliability of the PCB board after lamination.

[0023] Preferably, the hot melt module is made of the same material as the PCB circuit.

[0024] The hot melt module being made of the same material as the PCB circuit can simplify the production process, enable the simultaneous production of the hot melt module and the PCB circuit, and reduce the production cost.

[0025] Preferably, the hot melt module is provided with openings.

[0026] The design of the openings can facilitate the flow of the hot melt adhesive, improve the uniformity of the hot melt adhesive, reduce the phenomenon of unevenness on the surface of the PCB board after lamination, and improve the quality and reliability of the PCB board.

[0027] Preferably, the openings are arranged evenly within the hot melt module, and the shape of the openings is rectangular.

[0028] Arranging the openings evenly within the hot melt module and designing them in a rectangular shape can effectively control the flow direction of the hot melt adhesive, ensure that the hot melt adhesive is evenly distributed in the hot melt module area, reduce the phenomenon of uneven board thickness of the PCB board after lamination, and improve the quality of the PCB board.

[0029] The beneficial effects of the present utility model are as follows:

[0030] The present utility model provides a multi-layer PCB board. By setting heat conduction blocks on each layer and arranging hot melt modules within the heat conduction blocks, the projections of adjacent hot melt modules on the heat conduction blocks do not overlap. By setting the heat conduction blocks and the hot melt modules, heat can be effectively transferred to the hot melt adhesive, accelerating its melting and curing process, and improving the production efficiency of the PCB board. The design of non-overlapping projections of adjacent hot melt modules can effectively reduce the total thickness of the hot melt modules at the heat conduction blocks, thereby improving the problem of uneven board thickness and enhancing the production quality of the PCB board. Description of the Drawings

[0031] Figure 1 It is a partial view of the multi-layer PCB board provided in Embodiment 1 of the present application;

[0032] Figure 2 It is a partial view of the multi-layer PCB board provided in Embodiment 2 of the present application;

[0033] Figure 3 It is a partial view of the multi-layer PCB board provided in Embodiment 3 of the present application;

[0034] Figure 4 It is a partial view of the multi-layer PCB board provided in Embodiment 4 of the present application.

[0035] Reference numerals:

[0036] 100, heat conduction block; 200, hot melt module; 210, opening. Detailed implementation manners

[0037] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0038] Embodiment 1

[0039] As Figure 1 shown, this embodiment provides a multi-layer PCB board, which includes:

[0040] A heat conduction block 100 is provided between each layer of the PCB board. A hot melt module 200 for heat conduction is provided in each heat conduction block 100. The hot melt module 200 occupies a partial area of the heat conduction block 100, and the projections of adjacent hot melt modules 200 on the heat conduction block 100 do not overlap.

[0041] It should be noted that partial coverage means that the hot melt module 200 occupies a partial area of the heat conduction block 100, rather than complete coverage. The fact that the projections of adjacent hot melt modules 200 on the heat conduction block 100 do not overlap means that the corresponding positions of the hot melt modules 200 on adjacent two layers of PCB boards do not have an overlapping part on the heat conduction block 100, so as to avoid the thickness superposition of the hot melt modules 200.

[0042] Furthermore, the width and length of the heat-conducting block need to be comprehensively considered in combination with the specific design of the PCB board and the requirements of the hot pressing process. If the width of the heat-conducting block is too narrow, the area of the hot-melt module will be very small, reducing the heat-conducting efficiency. At the same time, the space left for the glue to flow is also small, which is not conducive to the uniform distribution of the glue layer and is prone to voids or glue overflow. If the width of the heat-conducting block is too wide, it will cause the hot-melt adhesive to spread too far, affecting the layout of other functional areas on the PCB board. If the length of the heat-conducting block is too short, the amount of heat that the hot-melt module can transfer will be reduced, which is not conducive to the rapid melting of the prepreg. If the length of the heat-conducting block is too long, it will cause heat stress concentration and is more likely to warp and deform.

[0043] Specifically, in this embodiment, the PCB board has 30 layers, the width of the heat-conducting block 100 is 5 mm, the length is 24 mm, and the heat-conducting block 100 is arranged at the corner of the PCB board.

[0044] More specifically, in this embodiment, the PCB board is a rectangular board, the heat-conducting block 100 is arranged near the four corner positions of the PCB board, the circuit material of the PCB board is copper, and the material of the hot-melt module 200 is also copper.

[0045] Even more specifically, the hot-melt module 200 can also be made of materials different from those of the PCB board, such as materials with good heat conductivity like aluminum, ceramics, etc. At this time, the hot-melt module 200 can be pre-fabricated and then mounted on the PCB board by SMT or other means.

[0046] Furthermore, the hot-melt module 200 and the circuit of the PCB adopt the same processing technology, and the redundant copper is removed by etching on the copper clad laminate, leaving the copper at the position of the hot-melt module 200.

[0047] More specifically, in this embodiment, the width of the hot-melt module 200 is the same as that of the heat-conducting block 100, which is also 5 mm, and the length of the hot-melt module 200 is half of the length of the heat-conducting block 100, with a length of 12 mm.

[0048] Even further, the hot-melt module 200 is also provided with openings 210. The shape of the openings 210 is rectangular. More specifically, the openings 210 are squares with a side length of 1 mm. The openings 210 are evenly arranged in the hot-melt module 200. There are two rows of openings 210, with 5 openings in each row. The vertical and horizontal intervals between the openings 210 are 1 mm, and the distance between the openings 210 and the edge of the hot-melt module 200 is 1 mm. In other words, the hot-melt module 200 is composed of a mesh structure of copper wires with a width of 1 mm. There are 3 copper wires arranged parallel in the length direction, with a spacing of 1 mm between the copper wires, and 6 copper wires arranged parallel in the width direction, with a spacing of 1 mm between the copper wires.

[0049] In the prior art, a copper layer is covered in the entire heat conduction block 100 of each layer of PCB board, and copper layers with a stacked thickness of 29 layers need to be added between 30 layers of boards. In this embodiment, only a hot melt module 200 with a stacked thickness of 15 layers needs to be added between 30 layers of boards.

[0050] Specifically, the shape of the opening 210 can be circular, triangular or other shapes that are beneficial to the flow of glue. The size and arrangement of the opening 210 can also be adjusted according to actual needs.

[0051] More specifically, in this embodiment, the heat conduction block 100 is symmetrically divided into a first block and a second block along the short axis, and two adjacent hot melt modules 200 of adjacent layers are respectively located in the first block and the second block. In other words, the hot melt modules 200 are alternately arranged in the first block or the second block in the PCB board.

[0052] Furthermore, the thickness of the hot melt module 200 is less than the thickness of the PCB board substrate.

[0053] When performing hot pressing of the PCB board, high temperature and high pressure are applied to the PCB board. At this time, due to its copper structure, the hot melt module 200 can transfer heat quickly and evenly, causing the prepreg below and around it to melt rapidly. The opening 210 structure on the hot melt module 200 is beneficial to the flow and filling of the melted glue, further ensuring the uniformity and firmness of the adhesion between each layer of PCB board.

[0054] The multi-layer PCB board provided in this embodiment is provided with a heat conduction block 100 between each layer of PCB board, and a hot melt module 200 with an opening 210 structure arranged in a staggered manner is adopted. The copper structure of the hot melt module 200 can transfer heat quickly and evenly, improving the hot pressing efficiency. The opening 210 on the hot melt module 200 is beneficial to the flow and filling of the melted glue, avoiding the accumulation or shortage of the glue layer, and improving the uniformity and reliability of the adhesion. The hot melt modules 200 are arranged in a staggered manner and do not cover the entire heat conduction block 100, which is beneficial to the uniform distribution of heat, and can also reduce the overall thickness of the hot melt module 200, preventing the PCB board from bulging or warping due to the excessive thickness of the hot melt module 200.

[0055] Embodiment 2

[0056] As Figure 2 shown, this embodiment provides a multi-layer PCB board, which includes:

[0057] A heat conduction block 100 is provided between each layer of the PCB board, a hot melt module 200 for heat conduction is provided in the heat conduction block 100, the hot melt module 200 occupies a partial area of the heat conduction block 100, and the projections of adjacent hot melt modules 200 on the heat conduction block 100 do not overlap.

[0058] Specifically, in this embodiment, the multilayer PCB board is provided with a total of 20 layers. The circuit material of the PCB board is silver material. The heat conduction block 100 is arranged at the corners and the centers of each side of the PCB board. The heat conduction block 100 is a rectangular area with a width of 4 mm and a length of 26 mm.

[0059] Further, the hot melt module 200 is arranged along the length direction of the heat conduction block 100.

[0060] Specifically, the hot melt module 200 is composed of silver wires with a width of 1 mm. The silver wires are arranged in parallel along the length direction of the heat conduction block 100. The distance between adjacent silver wires is 1 mm and the length is 26 mm.

[0061] To more clearly illustrate the arrangement of the hot melt blocks in this embodiment, in this embodiment, the heat conduction block 100 is divided into 4 rows. The length of each row is 26 mm and the width is 1 mm. The hot melt modules 200 of adjacent layers are respectively located in the odd rows and even rows of the heat conduction block 100. In this embodiment, the hot melt modules 200 of adjacent layers are respectively located in the 1st, 3rd rows and the 2nd, 4th rows.

[0062] In the prior art, when a copper layer is covered in the entire heat conduction block 100 of each layer of the PCB board, it is necessary to add a copper layer with a stacking thickness of 19 layers between 20 layers of boards. However, in this embodiment, it is only necessary to add hot melt modules 200 with a stacking thickness of 10 layers between 20 layers of boards.

[0063] The multilayer PCB board provided in this embodiment, by arranging the heat conduction block 100 with strip-shaped hot melt modules 200 between each layer of the PCB board and adopting a staggered arrangement, the silver wire structure of the hot melt module 200 can quickly and evenly transfer heat along the length direction, improving the hot pressing efficiency, especially suitable for PCB boards with a relatively large length. The strip-shaped hot melt module 200 and the staggered arrangement are beneficial to more uniform heat distribution, reducing the heat stress concentration in the length direction of the PCB board, effectively preventing the PCB board from warping and deforming, and improving the dimensional stability of the PCB board.

[0064] Embodiment 3

[0065] As Figure 3 shown, this embodiment provides a multilayer PCB board, which includes:

[0066] A heat conduction block 100 is provided between each layer of the PCB board. A hot melt module 200 for heat conduction is provided in the heat conduction block 100. The hot melt module 200 occupies a partial area of the heat conduction block 100. The projections of adjacent hot melt modules 200 on the heat conduction block 100 do not overlap.

[0067] Specifically, in this embodiment, the multi-layer PCB board is provided with a total of 35 layers. The circuit material of the PCB board is copper material. The heat conduction block 100 is arranged at the corner of the PCB board. The heat conduction block 100 is a rectangular area with a width of 6 mm and a length of 22 mm. The heat conduction block 100 is divided into 6 rows, and the length of each row is 26 mm and the width is 1 mm.

[0068] Further, the adjacent hot melt modules 200 extend inward along the two wide sides of the heat conduction block 100 in the length direction.

[0069] Specifically, the adjacent hot melt modules 200 are symmetrically arranged in a zipper shape.

[0070] More specifically, among the adjacent hot melt modules 200, one hot melt module 200 extends 6 mm inward along one wide side of the heat conduction block 100, and then continues to extend 10 mm along the even rows; the other hot melt module 200 extends 6 mm inward along the other wide side of the heat conduction block 100, and then continues to extend 10 mm along the odd rows.

[0071] Furthermore, the hot melt module 200 is also provided with a window 210. The window 210 is an equilateral triangle with a side length of 1 mm, and one side of the equilateral triangle is parallel to the wide side of the heat conduction block 100.

[0072] In the prior art, when covering the copper layer in the entire heat conduction block 100 of each layer of the PCB board, it is necessary to add a copper layer with a stacking thickness of 34 layers between 35 layers of boards. In this embodiment, it is only necessary to add hot melt modules 200 with a stacking thickness of 17 layers between 30 layers of boards.

[0073] More specifically, the equilateral triangle window 210 is arranged within a range of 6 mm from the heat conduction block 100 of the hot melt module 200. In order to more clearly illustrate the position of the window 210, the hot melt module 200 is divided into 6 rows and 6 columns, and the width of each column and each row is 1 mm. The window 210 is arranged within the range of rows 2 - 5 and columns 2 - 5. Among them, the equilateral triangle windows 210 in the even columns point inward, the equilateral triangle windows 210 in the odd columns point outward, and the windows 210 in the even columns and odd columns are arranged in a staggered manner.

[0074] When performing hot pressing of the multi-layer PCB board, high temperature and high pressure are applied to the PCB board. The copper-based hot melt module 200 can quickly and evenly transfer heat, so that the prepreg around it melts rapidly, thereby firmly bonding each layer of the PCB board together. At the same time, the "zipper-shaped" design and the triangular window 210 can guide the flow and distribution of the glue, ensuring the uniformity and reliability of the bonding.

[0075] Embodiment 4

[0076] Such as Figure 4As shown in the figure, this embodiment provides a multi-layer PCB board, which includes:

[0077] A heat conduction block 100 is provided between each layer of the PCB board. A hot melt module 200 for heat conduction is provided in each heat conduction block 100. The hot melt module 200 occupies a partial area of the heat conduction block 100, and the projections of adjacent hot melt modules 200 on the heat conduction block 100 do not overlap.

[0078] Specifically, in this embodiment, the multi-layer PCB board is provided with a total of 15 layers. The circuit material of the PCB board is copper material. The heat conduction block 100 is arranged at the corners of the PCB board. The heat conduction block 100 is a rectangular area with a width of 6 mm and a length of 26 mm.

[0079] Further, adjacent hot melt modules 200 extend inward along the two wide sides of the heat conduction block 100 along the length direction.

[0080] More specifically, adjacent hot melt modules 200 respectively extend 10 mm inward along the two 6-mm wide sides of the heat conduction block 100. The projected area of two adjacent hot melt modules 200 on the heat conduction block 100 is smaller than the area of the heat conduction block 100. Specifically, in this embodiment, the area of the PCB board in the heat conduction block 100 is 156 square millimeters, and the projected area of two adjacent hot melt modules 200 on the heat conduction block 100 is 120 square millimeters.

[0081] In the prior art, when a copper layer is covered in the entire heat conduction block 100 of each layer of the PCB board, a copper layer with a stacked thickness of 14 layers needs to be added between 15 layers of boards. In this embodiment, only a hot melt module 200 with a stacked thickness of 7 layers needs to be added between 15 layers of boards.

[0082] In the multi-layer PCB board of this embodiment, the area of adjacent hot melt modules 200 is smaller than the area of the PCB board in the heat conduction block 100, and the areas of adjacent hot melt blocks in the heat conduction block 100 do not overlap, which can effectively avoid the problem of the PCB board bulging caused by the thickness stacking of the hot melt module 200. At the same time, it can improve the hot pressing efficiency and pressing effect of the PCB board and ensure the pressing quality of the PCB board.

[0083] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present application. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0084] In addition, it should be noted that the use of terms such as "first" and "second" is only for the convenience of distinction. Without additional declaration, the above terms have no special meaning, and therefore should not be construed as a limitation on the protection scope of this application.

[0085] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, various modifications and changes can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A multi-layer PCB board, characterized in that, Comprising: Each layer of the PCB board is provided with a heat conduction block (100), and a hot melt module (200) for heat conduction is arranged in each heat conduction block (100). The hot melt module (200) occupies a partial area of the heat conduction block (100), and the projections of adjacent hot melt modules (200) on the heat conduction block (100) do not overlap.

2. The multi-layer PCB board according to claim 1, wherein The heat conduction block (100) is rectangular, and the hot melt module (200) is distributed along the length direction or the width direction of the heat conduction block (100).

3. The multi-layer PCB board according to claim 1, characterized in that, The projected area of adjacent hot melt modules (200) on the heat conduction block (100) is equal to the area of the heat conduction block (100).

4. The multi-layer PCB board according to claim 2, characterized in that, Adjacent hot melt modules (200) respectively extend inwards along the two wide sides of the heat conduction block (100).

5. The multilayer PCB board according to claim 2, characterized in that, The hot melt module (200) occupies half of the area of the heat conduction block (100).

6. The multi-layer PCB board according to claim 5, characterized in that, The heat conduction block (100) is arranged near the corner of the PCB board. The width of the heat conduction block (100) is 4 mm to 6 mm, and the length is 22 mm to 26 mm. The width of the hot melt module (200) is the same as the width of the heat conduction block (100), and the length of the hot melt module (200) is equal to half of the length of the heat conduction block (100).

7. The multi-layer PCB board according to any one of claims 1-6, characterized in that, The thickness of the hot melt module (200) is less than or equal to the thickness of the PCB board substrate.

8. The multi-layer PCB board according to any one of claims 1-6, characterized in that, The hot melt module (200) is made of the same material as the PCB circuit.

9. The multilayer PCB board according to any one of claims 1-6, characterized in that, A window opening (210) is provided on the hot melt module (200).

10. The multilayer PCB board according to claim 9, wherein, The window openings (210) are arranged evenly in the hot melt module (200), and the shape of the window opening (210) is rectangular.

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