Multi-layer circuit board pressing method and multi-layer circuit board

Abstract

The invention discloses a multilayer circuit board pressing method and a multilayer circuit board. The multilayer circuit board laminating method comprises the following steps: providing a first circuit board; one side surface of the first circuit board comprises a fixing hole setting area; a groove is formed in the fixing hole setting area; a fixing hole penetrating through the first circuit board is formed in the bottom of the groove through punching equipment; sequentially stacking the target number of first circuit boards and prepregs according to the stacking design for pre-typesetting; and fixing the first circuit board and the prepreg through a pin by adopting a pin positioning lamination process, and then pressing. By the adoption of the scheme, the punching capacity requirement of punching equipment can be met, manual single punching is not needed, the preparation efficiency of fixing holes is improved, and the punching technological process is simplified; and the alignment precision of the fixing holes and the perpendicularity of the fixing holes can be improved, so that the quality of the fixing holes is improved, the fixing effect is ensured, and the production yield of the multilayer circuit board is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of printed circuit boards, and in particular to a multi-layer circuit board lamination method and a multi-layer circuit board. Background Art

[0002] In order to ensure the signal integrity of the printed circuit board (PCB), thicker copper clad laminates are generally used in PCB stacking design to avoid signal interference between adjacent layers, thereby obtaining PCB products with stable signals. Among them, the use of thicker copper clad laminates (the thickness of the copper clad laminate is generally more than 1.4mm, and the thickness of the PCB is more than 3.0mm) in the stacking increases the difficulty of PCB process design and production, such as the pressing process, the design and production of fixing holes, and the alignment accuracy of the thick plate fixing holes, which directly or indirectly affects the quality yield of PCB products. Summary of the invention

[0003] In view of this, the present invention provides a multi-layer circuit board pressing method and a multi-layer circuit board, so as to reduce the difficulty of alignment pressing of the multi-layer circuit board and improve the alignment accuracy.

[0004] In a first aspect, an embodiment of the present invention provides a multi-layer circuit board lamination method, comprising:

[0005] A first circuit board is provided; a surface of one side of the first circuit board includes a fixing hole setting area;

[0006] forming a groove in the fixing hole setting area;

[0007] A fixing hole penetrating the first circuit board is formed at the bottom of the groove by using a punching device; the orthographic projection of the groove on the plane where the first circuit board is located covers the orthographic projection of the fixing hole on the plane where the first circuit board is located;

[0008] According to the stacking design, a target number of first circuit boards and prepregs are sequentially stacked for pre-layout;

[0009] The pin-positioning lamination process is adopted, and the first circuit board and the prepreg are fixed and pressed together by pins; wherein the pins pass through all the fixing holes and grooves of the first circuit board.

[0010] In a second aspect, an embodiment of the present invention provides a multi-layer circuit board, which is formed by the multi-layer circuit board lamination method of the first aspect of the present invention; the multi-layer circuit board includes at least two layers of first circuit boards and pins for fixing the first circuit boards;

[0011] The first circuit board includes a groove and a fixing hole, the groove is located on one side surface of the first circuit board, the fixing hole is located at the bottom of the groove and passes through the first circuit board; the pin passes through all the fixing holes and grooves of the first circuit board.

[0012] The multi-layer circuit board pressing method provided by the embodiment of the present invention is to first thin the fixing hole setting area of ​​the first circuit board to form a groove before punching with a punching device. The thickness of the first circuit board at the groove is relatively low, which can meet the punching capacity requirements of the punching device. There is no need to punch a single hole manually, which can improve the preparation efficiency of the fixing hole and simplify the punching process. In addition, the presence of the groove can also improve the alignment accuracy of the fixing hole and the verticality of the fixing hole, thereby improving the quality of the fixing hole. The pin positioning lamination process is used to fix the first circuit board and the semi-cured sheet and then press them together, which can further improve the alignment accuracy of the circuit board and improve the production yield of the multi-layer circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A flowchart of a multi-layer circuit board lamination method provided by an embodiment of the present invention;

[0014] Figure 2 for Figure 1 A schematic diagram of a multi-layer circuit board lamination method is shown;

[0015] Figure 3 A comparison diagram of the verticality of fixing holes provided in an embodiment of the present invention;

[0016] Figure 4 A schematic diagram of a partial structure of a first circuit board provided in an embodiment of the present invention;

[0017] Figure 5 A schematic diagram of the structure of a groove and a gasket provided in an embodiment of the present invention;

[0018] Figure 6 A schematic cross-sectional structure diagram of a first circuit board provided in an embodiment of the present invention;

[0019] Figure 7 A schematic diagram of a PE-PUNCH punching provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0021] It should be noted that the terms “having”, “including”, “comprising”, etc. described in the present application are all open-ended meanings, that is, when describing a module as “having”, “including” or “comprising” a first element, a second element and / or a third element, it means that the module includes other elements in addition to the first element, the second element and / or the third element. In addition, ordinal numbers such as “first”, “second” and “third” in the present application are not intended to limit a specific order, but only to distinguish between the various parts. In the present application, when describing that layer A and layer B are “set in the same layer”, it means that layer A and layer B are made of the same material and process.

[0022] The multi-layer circuit board lamination method provided by the embodiment of the present invention is suitable for the alignment and lamination between thicker circuit boards. The alignment and lamination process of the multi-layer circuit board includes process flows such as punching, pre-layout, layout and pressing. Punching refers to forming fixed holes on each circuit board using a punching device; pre-layout refers to stacking and arranging multiple circuit boards and prepregs in sequence according to the stacking design of the multi-layer circuit board; layout refers to inserting positioning pins into the fixed holes of the circuit board using a laminating device to fix the circuit board and the prepreg; pressing refers to firmly bonding multiple circuit boards together using the prepreg by applying high pressure and high temperature. Among them, in the punching process, due to the limited punching capacity of the automatic punching equipment, for some thicker circuit boards that have exceeded the punching capacity of the punching equipment, the relevant technology generally adopts CCD to grasp the target positioning and manually punch one by one. In this way, the complexity of the punching process is increased, and the alignment accuracy and the verticality of the plate thickness punching are poor, which may lead to poor quality of the fixed holes and local deformation of the circuit board, thereby reducing the production yield of the multi-layer circuit board.

[0023] Based on the above-mentioned defects of the related art, the present invention provides a multi-layer circuit board lamination method, comprising:

[0024] A first circuit board is provided; a surface of one side of the first circuit board includes a fixing hole setting area;

[0025] forming a groove in the fixing hole setting area;

[0026] A fixing hole penetrating the first circuit board is formed at the bottom of the groove by using a punching device; the orthographic projection of the groove on the plane where the first circuit board is located covers the orthographic projection of the fixing hole on the plane where the first circuit board is located;

[0027] According to the stacking design, a target number of first circuit boards and prepregs are sequentially stacked for pre-layout;

[0028] The pin-positioning lamination process is adopted, and the first circuit board and the prepreg are fixed and pressed together by pins; wherein the pins pass through all the fixing holes and grooves of the first circuit board.

[0029] The multi-layer circuit board pressing method provided by the embodiment of the present invention is to first thin the fixing hole setting area of ​​the first circuit board to form a groove before punching with a punching device. The thickness of the first circuit board at the groove is relatively low, which can meet the punching capacity requirements of the punching device. There is no need to punch a single hole manually, which can improve the preparation efficiency of the fixing hole and simplify the punching process. In addition, the presence of the groove can also improve the alignment accuracy of the fixing hole and the verticality of the fixing hole, thereby improving the quality of the fixing hole. The pin positioning lamination process is used to fix the first circuit board and the semi-cured sheet and then press them together, which can further improve the alignment accuracy of the circuit board and improve the production yield of the multi-layer circuit board.

[0030] The above is the core idea of ​​the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Figure 1 A flowchart of a multi-layer circuit board lamination method provided by an embodiment of the present invention. Figure 2 for Figure 1 The schematic diagram of the multi-layer circuit board lamination method shown in the figure can be referred to Figure 1 and Figure 2 , the multi-layer circuit board lamination method includes the following steps:

[0032] S110: Provide a first circuit board.

[0033] like Figure 2 As shown in Figure (a), one side surface of the first circuit board 10 includes a fixing hole setting area 11. The first circuit board 10 may refer to a single circuit board to be pressed together, and the thickness of the first circuit board 10 generally exceeds the maximum punching plate thickness of the punching equipment, that is, exceeds the punching capacity of the punching equipment. The first circuit board 10 may be a single-layer board or a double-layer board, which is not limited in the embodiment of the present invention. When the first circuit board 10 is a single-layer board, the first circuit board 10 includes a core board 101 and a copper foil layer 102 located on one side surface of the core board 101; when the first circuit board 10 is a double-layer board, the first circuit board 10 includes a core board 101 and a copper foil layer 102 located on both side surfaces of the core board 101. Figure 2 Figure (a) is a schematic diagram of the cross-sectional structure of the first circuit board 10. The fixing hole setting area 11 refers to the area where the fixing holes are to be formed later. A plurality of fixing hole setting areas 11 can be divided on one side of the first circuit board 10. The layout of the fixing hole setting areas 11 can be designed according to actual needs, and the embodiment of the present invention is not limited to this. For example, the fixing hole setting areas 11 can be distributed in a cross shape on the surface of the first circuit board 10, but are not limited thereto.

[0034] S120, forming a groove in the fixing hole setting area.

[0035] like Figure 2 As shown in FIG. (b), a groove 20 may be formed in the fixing hole setting area 11. The surface of the first circuit board 10 where the fixing hole setting area 11 is demarcated is defined as the first surface 10a of the first circuit board 10, and the other surface is defined as the second surface 10b. The groove 20 extends from the first surface 10a to the second surface 10b to a certain depth.

[0036] Exemplarily, a mechanical device may be used to thin the first circuit board 10 in the area surrounding the fixing hole setting area 11 to form a groove 20 in the fixing hole setting area 11, that is, after this process, the thickness of the first circuit board 10 in the fixing hole setting area 11 is less than the thickness of other areas. The shape and size of the orthographic projection figure of the groove 20 on the plane where the first circuit board 10 is located may be the same as the shape and size of the orthographic projection figure of the fixing hole 30 on the plane where the first circuit board 10 is located. Accordingly, the grooves 20 are distributed in a cross shape on the first surface 10a of the first circuit board 10.

[0037] The preparation process of the groove 20 is not limited, and those skilled in the art can select any process that can form the groove 20 on the surface of the first circuit board 10 according to actual needs.

[0038] S130, using a punching device to form a fixing hole penetrating the first circuit board at the bottom of the groove.

[0039] For further reference, Figure 2 In the middle (c) figure, after the first circuit board 10 at the fixing hole setting area 11 is thinned, the first circuit board 10 is punched by a punching device. Among them, the orthographic projection of the groove 20 on the plane where the first circuit board 10 is located covers the orthographic projection of the fixing hole 30 on the plane where the first circuit board 10 is located, that is, the fixing hole 30 is punched at the thinner groove 20, and the fixing hole 30 penetrates the first circuit board 10 in the thickness direction of the first circuit board 10. The fixing hole 30 is used for the subsequent alignment and fixation between multiple first circuit boards 10.

[0040] In this setting mode, since the first circuit board 10 at the fixing hole setting area 11 is thinned before punching, the punching plate thickness that the punching equipment needs to complete is reduced, which can meet the punching capacity requirements of the punching equipment. When the overall thickness of the first circuit board 10 exceeds the punching capacity of the punching equipment (for example, the circuit board thickness is greater than 1.2mm), the distance between the bottom of the groove 20 and the second surface 10b can be controlled to be less than or equal to the maximum punching plate thickness of the punching equipment (that is, the maximum circuit board thickness limited by the punching capacity), so that the punching equipment is used to automatically form a fixing hole 30 in the groove 20. Compared with the manual single drilling solution in the related art, the solution of the present invention can improve the preparation efficiency of the fixing hole 30 and simplify the punching process. In addition, the presence of the groove 20 can also improve the alignment accuracy of the fixing hole 30 and the verticality of the fixing hole 30, thereby improving the quality of the fixing hole 30 and improving the production yield of multi-layer circuit boards.

[0041] Figure 3 A comparison diagram of the verticality of the fixing holes provided in the embodiment of the present invention, Figure 3 Figure (a) shows a fixing hole 30 prepared by a manual punching process in the related art. Figure 3 Figure (b) shows a fixing hole 30 formed by first thinning to form a groove 20 and then automatically punching the fixing hole 30. By comparing the two figures, it can be seen that the verticality of the fixing hole 30 formed by the technical solution of the present invention is improved.

[0042] S140, stacking a target number of first circuit boards and prepregs in sequence according to the stacking design for pre-layout.

[0043] The stacking design is a design scheme for the number of layers of a multi-layer circuit board required by a user. The number of layers of the first circuit board 10 in the stacking design is the target number, and the value of the target number is not limited, for example, it can be 2, 4 or 6. Figure 2 The figure (d) in the middle is taken as an example with the number of targets being 2, but the actual example is not limited to this.

[0044] It should be noted that the stacked design may also include a second circuit board 40, which is a thinner circuit board within the punching capacity of the punching equipment. This part of the circuit board does not need to undergo the above-mentioned thinning treatment (S120), and can be directly punched automatically to form the fixing holes 30 in the fixing hole setting area 11.

[0045] like Figure 2As shown in Figure (d), the target number of first circuit boards 10 can be stacked according to the stacking design, and the two adjacent first circuit boards 10 are separated by a prepreg 50 to complete the pre-layout. The stacking design in the figure exemplarily shows that the first circuit board 10 is a double-layer board, the second circuit board 40 is a single-layer board, and the two second circuit boards 40 are located between the two first circuit boards 10, but it is not limited to this. During pre-layout, it is necessary to ensure that the fixing holes 30 of multiple circuit boards are aligned one by one.

[0046] S150, using a pin positioning lamination process, the first circuit board and the prepreg are fixed by pins and then pressed together.

[0047] For further reference, Figure 2 In the middle (e) figure, in this embodiment, the pin-positioning lamination (PIN-LAM) process can be used to position and press the circuit boards. The pin-positioning lamination process has high positioning accuracy and is more suitable for the production of thick circuit boards. The stacked structure formed by the first circuit board 10 and the prepreg 50 can be placed on the machine of the pin-positioning lamination process. After the pin 60 is accurately aligned with the fixing hole 30, the pin 60 is driven into the stacked structure, so that the pin 60 passes through all the fixing holes 30 and grooves 20 of the first circuit board 10, and the alignment and fixation of the multi-layer circuit board is completed, and then the pressing process is performed.

[0048] The pressing plate process can be implemented by any existing technology, and the embodiments of the present invention are not limited to this. For example, pressing plate assemblies (the pressing plate assemblies include stacked steel plates, buffer layers and cover plates, etc.) can be set on both sides of the stacked plate structure, and the pressing plate assemblies are used for pressing.

[0049] The multi-layer circuit board pressing method provided by the embodiment of the present invention is to first thin the fixing hole setting area of ​​the first circuit board to form a groove before punching with a punching device. The thickness of the first circuit board at the groove is relatively low, which can meet the punching capacity requirements of the punching device. There is no need to punch a single hole manually, which can improve the preparation efficiency of the fixing hole and simplify the punching process. In addition, the presence of the groove can also improve the alignment accuracy of the fixing hole and the verticality of the fixing hole, thereby improving the quality of the fixing hole. The pin positioning lamination process is used to fix the first circuit board and the semi-cured sheet and then press them together, which can further improve the alignment accuracy of the circuit board and improve the production yield of the multi-layer circuit board.

[0050] Optionally, in a possible embodiment, (S120) in the above embodiment may be refined as follows: using a milling device to mill the first circuit board at the fixing hole setting area to a preset depth to form a groove.

[0051] The milling equipment is a mechanical tool used to process the plate, which mainly realizes cutting, grinding, chamfering and other operations on the plate by rotating the milling cutter and moving the workpiece. As an optional solution, the first circuit board at the fixing hole setting area can be milled thin by the milling equipment to a preset depth to form a groove, and the preset depth is the depth of the groove.

[0052] Among them, the specific value of the preset depth is not limited, and technical personnel in this field can set it according to actual needs to ensure that the distance from the bottom of the groove to the second surface of the first circuit board is less than or equal to the maximum punching plate thickness of the punching equipment.

[0053] In this embodiment, the milling equipment is used to thin the fixing hole setting area of ​​the first circuit board, so that the shape and size of the groove can be controlled more accurately, so that the first circuit board at the groove (fixing hole setting area) can be milled thin to within the punching capacity range of the punching equipment, thereby improving the punching success rate.

[0054] Of course, in other embodiments, the grooves can be prepared by any other mechanical equipment, such as laser cutting equipment, but are not limited thereto, and the embodiments of the present invention do not elaborate on this and do not limit this. In addition, the embodiments of the present invention do not limit the specific structure of the milling equipment and the specific process of using the milling equipment to thin the first circuit board 10. Any milling equipment that can achieve the corresponding function is within the scope of the technical solution protected by the present invention.

[0055] Optionally, in a possible embodiment, the area of ​​the orthographic projection figure of the groove on the plane where the first circuit board is located is larger than the area of ​​the orthographic projection figure of the fixing hole on the plane where the first circuit board is located; after (S120) of the above embodiment, it also includes: placing a gasket on the side wall of the groove, the gasket covers the side wall of the groove; after fixing the first circuit board and the semi-cured sheet by pins, the gasket fills the space between the pins and the side wall of the groove.

[0056] Figure 4 A schematic diagram of a partial structure of a first circuit board provided in an embodiment of the present invention, Figure 4 FIG. 1 is a top view of the first circuit board 10 at the fixing hole setting area. Figure 4 The graphic shapes shown are the orthographic projection graphic shapes of each part on the plane where the first circuit board 10 is located. Figure 2 Figure (e) and Figure 4 In the orthographic projection figure on the plane where the first circuit board 10 is located, the area of ​​the groove 20 figure is larger than the area of ​​the fixing hole 30 figure, for example, the length of the groove 20 figure is 0.1-0.2 mm larger than the length of the fixing hole 30 figure, and / or, the width of the groove 20 figure is 0.1-0.2 mm larger than the width of the fixing hole 30 figure, in other words, the inner diameter of the groove 20 figure is 0.1-0.2 mm larger than the inner diameter of the fixing hole 30.

[0057] It can be understood that the size of the fixing hole 30 is the same as the punching size of the punching device, and setting the size of the groove 20 slightly larger than the punching size of the punching device can ensure that the groove 20 and the punching device have a high alignment accuracy, thereby ensuring that the fixing hole 30 is aligned with the groove 20, and making the center of the fixing hole 30 and the center of the bottom of the groove 20 in the same vertical direction as much as possible. The vertical direction is the direction perpendicular to the plane where the first circuit board 10 is located, and can also be regarded as the thickness direction of the first circuit board 10.

[0058] Furthermore, the size of the pin 60 used to fix the circuit board matches the shape and size of the fixing hole 30. When the size of the groove 20 is larger than the size of the fixing hole 30, when the pin 60 is subsequently inserted into the first circuit board 10, there will be a certain gap between the part of the pin 60 in the groove 20 and the side wall of the groove. The pin 60 may be offset when passing through the groove 20, affecting the alignment accuracy.

[0059] Based on this, this embodiment proposes that before pre-layout, a gasket 70 may be placed in the groove 20, and the gasket 70 covers the side wall of the groove. Figure 4 , in the orthographic projection graphic on the plane where the first circuit board 10 is located, the overall shape and size of the gasket 70 match the shape and size of the groove 20 (for example, they can be exactly the same). The gasket 70 includes an opening in the middle. In the orthographic projection graphic on the plane where the first circuit board 10 is located, the shape and size of the opening match the shape and size of the fixing hole 30 (pin 60) (for example, they can be exactly the same). After the pin 60 is inserted into the first circuit board 10, the gasket 70 is located between the pin 60 and the side wall of the groove, and the gasket 70 fills at least part of the gap between the pin 60 and the side wall of the groove, thereby avoiding the deviation of the pin 60 and improving the alignment accuracy. In order to clearly distinguish the groove 20, the fixing hole (pin 60) and the gasket 70, Figure 4 The example shows that there is a gap between the groove 20 and the gasket 70, and between the fixing hole (pin 60) and the gasket 70. In actual situation, there should be no gap, and the two adjacent parts should fit closely to ensure the firmness of the fixation.

[0060] Optionally, in some embodiments, the gasket 70 is made of a high temperature resistant material, and the thermal expansion coefficient of the gasket 70 material is ≤5%, so as to avoid deformation of the gasket 70 during subsequent high temperature pressing.

[0061] Further optional, Figure 5 A schematic diagram of a structure of a groove and a gasket provided in an embodiment of the present invention, Figure 5 is a schematic diagram of a partial cross-sectional structure of the first circuit board 10, which can be referred to Figure 5 In a possible embodiment, in a direction perpendicular to the plane where the first circuit board 10 is located, the depth of the groove 20 is H1, and the thickness of the gasket 70 is H2; H1=n×H2, where n is a natural number greater than 0.

[0062] like Figure 5 As shown, in this embodiment, the depth of the groove 20 in the direction perpendicular to the plane of the first circuit board 10 (i.e., the vertical direction Z) can match the thickness of the gasket 70 in this direction, and the matching of the two here means that the groove depth H1 is an integer multiple of the gasket thickness H2. Under this setting mode, placing a suitable number of gaskets 70 can ensure that the overall thickness of the gasket 70 in the groove 20 is the same as the depth of the groove 20, and the upper and lower surfaces of the gasket 70 are flush with the groove 20.

[0063] For example, assuming that the gasket thickness H2 is 0.5 mm, the groove depth H1 is an integer multiple of 0.5, such as 0.5 mm, 1 mm, etc. Of course, this value is only an example. In actual application, the gasket thickness H2 and the groove depth H1 can be any values ​​as long as they satisfy the above relationship.

[0064] Optional, Figure 6 A schematic diagram of a cross-sectional structure of a first circuit board provided in an embodiment of the present invention can be referred to Figure 6 In the direction perpendicular to the plane where the first circuit board 10 is located, the depth of the groove 20 is H1, the thickness of the first circuit board 10 is H3, and the depth of the fixing hole 30 is H4; H1 = H3-H4, H3≥H0, H0 is the maximum punching plate thickness of the punching equipment.

[0065] As described above, the thickness H3 of the first circuit board 10 exceeds the maximum punching plate thickness H0 of the punching device, that is, H3 ≥ H0, the groove depth H1 is the preset depth of thinning of the fixing hole setting area 11, and the fixing hole depth H4 is the actual punching plate thickness of the punching device. The sum of the groove depth H1 and the fixing hole depth H4 should be the first circuit board thickness H3.

[0066] Exemplarily, in some embodiments, it can be set that: H0=1.2 mm, 1.2 mm≤H3, 0.7 mm≤H4≤1.2 mm, so as to avoid damage to the circuit board fixing hole 30 due to insufficient thickness of the first circuit board 10 .

[0067] Optionally, in a possible embodiment, (S130) in the above embodiment may be refined as follows: placing the first circuit board on the machine surface of the punching device in a manner that the groove faces away from the machine surface of the punching device; and punching is performed after the punch of the punching device is aligned with the groove.

[0068] Punching with a punching device is generally performed upward, that is, the punch of the punching device moves upward from the machine surface, and the punch penetrates the first circuit board 10 to form a fixing hole 30. With respect to such an upward punching device, this embodiment further defines that when preparing the fixing hole 30, the second surface 10b of the first circuit board 10 is placed toward the punching device, that is, according to Figure 5 and Figure 6In the state shown in FIG, the first circuit board 10 is placed on the machine surface, so that the first circuit board 10 is in full contact with the punching equipment machine, thereby preventing the bottom of the punch from being suspended in the air and affecting the punching accuracy.

[0069] For further optional information, please refer to Figure 2 In the middle (e) figure, the number of copper foil layers 102 in the laminate structure is used as the number of layers of the laminate structure. Figure 2 The stacked board structure shown is a 6-layer board structure, which is L1-L6 layer, including two first circuit boards 10 in the middle and two second circuit boards 40 located on both sides of the first circuit boards 10. When punching in (S130), the holes are punched upward from the small surface. For example, for the first circuit boards 10 corresponding to the L2 and L3 layers, the groove 20 is located on the side of the L2 layer, and the punching is performed from the L3 layer to the L2 layer; for the first circuit boards 10 corresponding to the L4 and L5 layers, the groove 20 is located on the side of the L4 layer, and the punching is performed from the L5 layer to the L4 layer. When the pins 60 are used to pass through the fixing holes 30 to fix the multiple first circuit boards 10 in (S150), the pins 60 can be punched in from the L6 layer to the L1 layer.

[0070] Optional, you can continue to refer to Figure 2 The first circuit board 10 includes a plurality of fixing hole setting areas 11; (S120) in the above embodiment can be refined as follows: a groove is formed in each fixing hole setting area; (S130) can be refined as follows: a punching device is used to simultaneously form fixing holes penetrating the first circuit board at the bottom of a plurality of grooves; the grooves and the fixing holes correspond one to one.

[0071] As described in the above embodiment, the fixing hole setting area 11 can be distributed in a cross shape to improve the fixing effect. This embodiment further stipulates that the PE-PUNCH process can be used for punching. Figure 7 A PE-PUNCH punching schematic diagram provided in an embodiment of the present invention, refer to Figure 7 The punching die (i.e., the "punch" mentioned above) used in PE-PUNCH punching has a fixed spacing in the X direction, i.e., the positions of the four punches are fixed. After the groove of the first circuit board is aligned with the punch, four cross-shaped fixed holes 30 can be punched out at the same time, and the punching accuracy and punching efficiency are both high.

[0072] in, Figure 7 As shown in the figure, the fixing hole 30 located at the top is not in the X direction. The purpose is to prevent assembly errors through the asymmetry of the design, which is called "fool-proof design" in the industry.

[0073] Optional, continue to refer to Figure 4 In the orthographic projection figure on the plane where the first circuit board 10 is located, the shape contours of the groove 20, the fixing hole 30 and the pin 60 are the same to ensure the alignment accuracy and fixing effect between the circuit boards.

[0074] Based on the same concept, an embodiment of the present invention further provides a multi-layer circuit board, which is formed by the multi-layer circuit board lamination method provided by any embodiment of the present invention. Figure 2 As shown, the multilayer circuit board includes at least two layers of first circuit boards 10 and a pin 60 for fixing the first circuit boards 10; wherein the first circuit board 10 includes a groove 20 and a fixing hole 30, the groove 20 is located on one side surface of the first circuit board 10, and the fixing hole 30 is located at the bottom of the groove 20 and passes through the first circuit board 10; the pin 60 passes through all the fixing holes 30 and grooves 20 of the first circuit board 10.

[0075] The multilayer circuit board provided by the embodiment of the present invention can meet the punching capacity requirements of the punching equipment, and does not require manual single punching, which can improve the preparation efficiency of the fixing hole 30 and simplify the punching process. In addition, the presence of the groove 20 can also improve the alignment accuracy of the fixing hole 30 and the verticality of the fixing hole 30, thereby improving the quality of the fixing hole 30. Using the pin 60 to fix the first circuit board 10 and the prepreg 50 can further improve the alignment accuracy of the circuit board and improve the production yield of the multilayer circuit board.

[0076] Optional, you can continue to refer to Figure 2 In some embodiments, the multilayer circuit board further includes a gasket 70, which is located in the groove 20 and covers the side wall of the groove; the pin 60 is located on the side of the gasket 70 away from the side wall of the groove. In this way, the pin 60 can be prevented from being offset in the groove 20, thereby improving the alignment accuracy.

[0077] The multilayer circuit board provided in the embodiment of the present invention has all the technical features and corresponding beneficial effects of the multilayer circuit board lamination method provided in any embodiment of the present invention. The contents not described in detail here can refer to any of the above embodiments and will not be repeated here.

[0078] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A multi-layer circuit board lamination method, characterized in that: include: A first circuit board is provided; a surface of one side of the first circuit board includes a fixing hole setting area; forming a groove in the fixing hole setting area; A fixing hole penetrating the first circuit board is formed at the bottom of the groove by using a punching device; the orthographic projection of the groove on the plane where the first circuit board is located covers the orthographic projection of the fixing hole on the plane where the first circuit board is located; According to the stacking design, a target number of first circuit boards and prepregs are stacked in sequence for pre-layout; A pin-positioning lamination process is adopted, and the first circuit board and the prepreg are fixed and pressed together by pins; wherein the pins pass through the fixing holes and the grooves of all the first circuit boards.

2. The multi-layer circuit board lamination method according to claim 1, characterized in that: A groove is formed in the fixing hole setting area, comprising: The first circuit board at the fixing hole setting area is milled thin by a preset depth by using a milling device to form the groove.

3. The multi-layer circuit board lamination method according to claim 1, characterized in that: The area of ​​the orthographic projection of the groove on the plane where the first circuit board is located is larger than the area of ​​the orthographic projection of the fixing hole on the plane where the first circuit board is located; After the groove is formed in the fixing hole setting area, the method further comprises: Placing a gasket on the side wall of the groove, wherein the gasket covers the side wall of the groove; After the first circuit board and the prepreg are fixed by the pins, the gasket fills the space between the pins and the side wall of the groove.

4. The multi-layer circuit board lamination method according to claim 3, characterized in that: In a direction perpendicular to the plane where the first circuit board is located, the depth of the groove is H1, and the thickness of the gasket is H2; H1=n×H2, where n is a natural number greater than 0.

5. The multi-layer circuit board lamination method according to claim 1, characterized in that: In a direction perpendicular to the plane where the first circuit board is located, the depth of the groove is H1, the thickness of the first circuit board is H3, and the depth of the fixing hole is H4; H1=H3-H4, H3≥H0, H0 is the maximum punching plate thickness of the punching equipment.

6. The multi-layer circuit board lamination method according to claim 1, characterized in that: A fixing hole penetrating the first circuit board is formed at the bottom of the groove by a punching device, comprising: Placing the first circuit board on the surface of the punching device in a manner that the groove faces away from the surface of the punching device; The punching device performs punching after the punch head is aligned with the groove.

7. The multi-layer circuit board lamination method according to claim 1, characterized in that: The first circuit board includes a plurality of fixing hole arrangement areas; A groove is formed in the fixing hole setting area, comprising: One groove is correspondingly formed in each fixing hole setting area; A fixing hole penetrating the first circuit board is formed at the bottom of the groove by a punching device, comprising: The fixing holes penetrating the first circuit board are formed at the bottom of a plurality of the grooves at the same time by using the punching device; the grooves and the fixing holes correspond one to one.

8. The multi-layer circuit board lamination method according to claim 1, characterized in that: In the orthographic projection figure on the plane where the first circuit board is located, the shapes and contours of the groove, the fixing hole and the pin are the same.

9. A multi-layer circuit board, characterized in that: The multi-layer circuit board is formed by the lamination method of any one of claims 1 to 8; the multi-layer circuit board comprises at least two layers of first circuit boards and pins for fixing the first circuit boards; The first circuit board includes a groove and a fixing hole, wherein the groove is located on one side surface of the first circuit board, and the fixing hole is located at the bottom of the groove and passes through the first circuit board; the pin passes through all the fixing holes and the groove of the first circuit board.

10. The multi-layer circuit board according to claim 9, characterized in that: The multilayer circuit board also includes a gasket, which is located in the groove and covers the side wall of the groove; the pin is located on a side of the gasket away from the side wall of the groove.

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