Multilayer wiring board and method for laminating the same

Abstract

The application provides a multilayer circuit board and a laminating method thereof. The method comprises placing a plurality of copper foils and a plurality of fusion layers on a second pressing steel plate; driving a pressing motor to press down and extrude the copper foils by a first pressing steel plate, so that overflow glue in prepreg is discharged through a first overflow glue hole; and driving the pressing motor to lift up and separate the first pressing steel plate with the attached overflow glue from the copper foils. When the first and second pressing steel plates press the copper foils and the fusion layers, the prepreg is extruded and has excess glue, i.e. overflow glue, and the first overflow glue hole discharges the overflow glue, so that the overflow glue is extruded from between the first and second pressing steel plates, the overflow glue is quickly extruded, the overflow glue is easily removed, glue traces are avoided on the copper foils with circuits, and the risk of circuit short circuit of the multilayer circuit board is reduced.

Description

Technical Field

[0001] This invention relates to the field of circuit board technology, and in particular to a multilayer circuit board and a method for laminating the same. Background Technology

[0002] The production of multilayer boards requires the inner layers on both sides to be pressed together with PP and copper foil. PP will turn into a molten state at high temperature and will overflow to all sides after being squeezed. Excess glue will overflow to the edge of the board.

[0003] When manufacturing boards with special lamination structures such as copper-embedded boards and double-sided aluminum substrates, the presence of through holes or gaps on the board surface causes adhesive substances to flow through the gaps in the copper blocks or the holes in the core board onto the board surface after lamination and extrusion, forming a layer of black adhesive residue, as seen in applications CN202011586813.5 and CN202210593591.2. However, if this adhesive residue is not cleaned properly, it can cause risks such as short circuits. The only way to remove the residual adhesive is by ceramic polishing or manual polishing, leading to excessively high board manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multilayer circuit board and a method for removing excess adhesive from the same.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for laminating a multilayer circuit board includes: laminating a multilayer circuit board using a multilayer circuit board laminating device, wherein the multilayer circuit board laminating device includes: a laminating support plate and a board-making laminating assembly; the board-making laminating assembly includes a first laminating steel plate, a second laminating steel plate, and a laminating motor, wherein the second laminating steel plate is disposed on the laminating support plate and is used to place multiple copper foils and multiple fusion layers, and the lifting shaft of the laminating motor is connected to the first laminating steel plate to move the first laminating steel plate away from or closer to the second laminating steel plate, wherein the fusion layer includes an interconnected core board and a prepreg, and the first laminating steel plate has a first overflow hole;

[0007] The multilayer circuit board lamination method includes:

[0008] Multiple copper foils and multiple fusion layers are placed on a second press-fit steel plate;

[0009] The driving pressing motor presses down, squeezing the copper foil by the first pressing steel plate, so that the overflowing adhesive in the prepreg passes through the first overflow hole;

[0010] The drive pressing motor lifts up, separating the first pressing steel plate with excess adhesive from the copper foil.

[0011] In one embodiment, placing multiple copper foils and multiple fusion layers on a second pressing steel plate includes: placing multiple copper foils and multiple fusion layers in a staggered manner on the second pressing steel plate.

[0012] In one embodiment, the placement of multiple copper foils and multiple fusion layers on a second pressing steel plate further includes: stacking multiple kraft paper sheets on the side of the first pressing steel plate away from the copper foils.

[0013] In one embodiment, the step of stacking multiple kraft papers on the side of the first pressing steel plate away from the copper foil further includes placing a cover plate on the side of the kraft papers away from the first pressing steel plate, wherein the cover plate is fixedly connected to the lifting shaft of the pressing motor.

[0014] In one embodiment, the driving pressing motor presses down to squeeze the copper foil by the first pressing steel plate so that the overflow adhesive in the prepreg passes through the first overflow hole, including: driving the pressing motor to rotate forward, and the cover plate squeezing the first pressing steel plate by multiple kraft paper sheets.

[0015] In one embodiment, the drive pressing motor rotates forward, and the cover plate presses the first pressing steel plate through multiple kraft paper sheets. Then, the method further includes: pressing the fusion layer through the first pressing steel plate and the second pressing steel plate to squeeze the overflow glue in the fusion layer from the first overflow glue hole to the space between the first pressing steel plate and the kraft paper sheets.

[0016] In one embodiment, the upward movement of the drive pressing motor to detach the first pressing steel plate with excess adhesive from the copper foil includes: reversing the drive pressing motor to lift the cover plate away from the kraft paper; and removing the first pressing steel plate and the kraft paper thereon.

[0017] In one embodiment, the placement of multiple copper foils and multiple fusion layers on the second pressing steel plate further includes, before: stacking multiple kraft paper sheets on the pressing support plate.

[0018] In one embodiment, the second pressing steel plate has a second overflow hole; the driving pressing motor presses down to squeeze the copper foil of the first pressing steel plate so that the overflow of the prepreg passes through the first overflow hole, including: squeezing the fusion layer by the first pressing steel plate and the second pressing steel plate to squeeze the overflow of the fusion layer from the second overflow hole to the space between the second pressing steel plate and the kraft paper.

[0019] A multilayer circuit board is prepared using the multilayer circuit board lamination method described in any of the above embodiments.

[0020] Compared with the prior art, the present invention has at least the following advantages:

[0021] When the copper foil and fusion layer are pressed together by the first and second pressing steel plates, the prepreg is squeezed and there is excess glue, i.e., overflow glue. The first overflow glue hole guides the overflow glue, so that the overflow glue overflows from between the first and second pressing steel plates, thereby making the overflow glue squeezed out quickly, which is convenient to clean up the overflow glue and avoids the formation of glue residue on the copper foil with circuits, thereby reducing the probability of short circuits in the multilayer circuit board. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of a multilayer circuit board lamination method in one embodiment;

[0024] Figure 2 This is a schematic diagram showing the residual copper ratio and warpage of three embodiments of the second-side copper protrusion. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] This invention relates to a method for laminating a multilayer circuit board. In one embodiment, the method includes placing multiple copper foils and multiple fusion layers on a second pressing steel plate; driving a pressing motor to press down, squeezing the copper foils against a first pressing steel plate, so that excess adhesive overflowing from the prepreg passes through a first overflow hole; and driving the pressing motor to lift, detaching the first pressing steel plate with the excess adhesive from the copper foils. During the pressing of the copper foils and fusion layers by the first and second pressing steel plates, excess adhesive remains on the prepreg after compression, i.e., excess adhesive. The first overflow hole guides the excess adhesive out, allowing it to overflow between the first and second pressing steel plates. This rapid extrusion of the excess adhesive facilitates its removal, preventing adhesive residue from forming on the copper foil with circuitry, thereby reducing the probability of short circuits in the multilayer circuit board.

[0029] Please see Figure 1 This is a flowchart of a multilayer circuit board lamination method according to an embodiment of the present invention. The multilayer circuit board lamination method includes some or all of the following steps.

[0030] S100: Multiple copper foils and multiple fusion layers are placed on a second press-fit steel plate.

[0031] In this embodiment, the copper foil and the fusion layer are disposed on the second pressing steel plate, and the second pressing steel plate is placed on the pressing support plate, so that the copper foil and the fusion layer are stably placed on the second pressing steel plate. Moreover, there are multiple copper foils and multiple fusion layers, that is, multiple copper foils and multiple fusion layers are disposed together on the second pressing steel plate, which facilitates the subsequent pressing of the fusion layer and the copper foil to form a multilayer circuit board.

[0032] S200: Drive the pressing motor to press down and squeeze the copper foil by the first pressing steel plate so that the overflow adhesive in the prepreg passes through the first overflow hole.

[0033] In this embodiment, the pressing motor works in conjunction with the first pressing steel plate. Specifically, the pressing motor pushes the first pressing steel plate to press the copper foil, thereby pressing the copper foil and the fusion layer together to form a circuit board. During the pressing process, the first pressing steel plate presses the copper foil towards the second pressing steel plate. The first overflow hole on the first pressing steel plate squeezes out excess adhesive from the prepreg, facilitating the guidance of excess adhesive during the pressing process of the multilayer circuit board to the first pressing steel plate, thus facilitating the cleaning of excess adhesive. Before pressing, the copper foil and the fusion layer have through holes or gaps corresponding to the fusion layer. For example, the formed multilayer circuit board is a double-sided aluminum substrate or a copper-embedded plate, and the excess adhesive flows from the through holes or gaps to the first overflow hole.

[0034] S300: Drive the pressing motor to lift up and separate the first pressing steel plate with excess adhesive from the copper foil.

[0035] In this embodiment, the pressing motor works in conjunction with the first pressing steel plate. Specifically, the pressing motor pushes the first pressing steel plate to press the copper foil, thereby pressing the copper foil and the fusion layer together to form a circuit board. During the pressing process, the first pressing steel plate presses the copper foil towards the second pressing steel plate. The first overflow hole on the first pressing steel plate squeezes out excess adhesive from the prepreg, facilitating the guidance of excess adhesive during the pressing process of the multilayer circuit board to the first pressing steel plate, thus facilitating the cleaning of excess adhesive. Before pressing, the copper foil and the fusion layer have through holes or gaps corresponding to the fusion layer. For example, the formed multilayer circuit board is a double-sided aluminum substrate or a copper-embedded plate, and the excess adhesive flows from the through holes or gaps to the first overflow hole. During the lifting process of the pressing motor, that is, when the first pressing steel plate moves away from the second pressing steel plate, the first overflow hole on the first pressing steel plate squeezes out the excess overflow glue on the semi-cured sheet, which facilitates the adhesion of the overflow glue during the pressing process of the multilayer circuit board to the first pressing steel plate. Moreover, it is to attach as much overflow glue as possible to the side of the first pressing steel plate away from the second pressing steel plate, so as to facilitate the removal of more overflow glue when the first pressing steel plate is removed later.

[0036] In this embodiment, when the copper foil and the fusion layer are pressed together by the first and second pressing steel plates, the prepreg is squeezed and there is excess adhesive, i.e., overflow adhesive. The first overflow hole discharges the overflow adhesive, allowing it to overflow between the first and second pressing steel plates. This allows the overflow adhesive to be squeezed out quickly, making it easy to remove the overflow adhesive and avoid forming adhesive residue on the copper foil with circuits, thereby reducing the probability of short circuits in the multilayer circuit board.

[0037] In one embodiment, placing multiple copper foils and multiple fusion layers on a second pressing steel plate includes: sequentially and alternately stacking multiple copper foils and multiple fusion layers on the second pressing steel plate. In this embodiment, the copper foils and the fusion layers are disposed on the second pressing steel plate, which is placed on the pressing support plate, so that the copper foils and the fusion layers are stably placed on the second pressing steel plate. Moreover, there are multiple copper foils and multiple fusion layers, that is, multiple copper foils and multiple fusion layers are jointly disposed on the second pressing steel plate, which facilitates the subsequent pressing of the fusion layers and copper foils to form a multilayer circuit board. Specifically, the multiple copper foils and multiple fusion layers alternate; the multiple fusion layers are located between two copper foils, and the two copper foils are in contact with the first pressing steel plate and the second pressing steel plate respectively, which facilitates the pressing of the multiple fusion layers by the two copper foils to form a multilayer circuit board.

[0038] In one embodiment, after placing multiple copper foils and multiple fusion layers on the second pressing steel plate, the method further includes: stacking multiple sheets of kraft paper on the side of the first pressing steel plate opposite to the copper foil. In this embodiment, the first pressing steel plate is placed on the copper foil, and the first pressing steel plate presses the multiple fusion layers through the copper foil to achieve bonding between the copper foil and the fusion layers. The bonding between the first pressing steel plate and the second pressing steel plate is achieved under the drive of the pressing motor. Before bonding, multiple sheets of kraft paper are placed on the first pressing steel plate to ensure that the force exerted by the pressing motor on the first pressing steel plate is balanced, facilitating complete bonding between the copper foil and the fusion layers and improving the bonding stability between the copper foil and the fusion layers.

[0039] Further, the step of stacking multiple kraft papers on the side of the first pressing steel plate away from the copper foil includes placing a cover plate on the side of the kraft papers away from the first pressing steel plate, wherein the cover plate is fixedly connected to the lifting shaft of the pressing motor. In this embodiment, the kraft paper is located between the cover plate and the first pressing steel plate, and the kraft paper provides a buffering force for the first pressing steel plate to avoid damage to it. The cover plate is fixedly connected to the lifting shaft of the pressing motor, and the lifting shaft of the pressing motor drives the cover plate to move, causing the cover plate to face or move away from the kraft paper, thereby causing the cover plate to press against the first pressing steel plate, facilitating the pressing of the copper foil and the fusion layer by the first pressing steel plate and the second pressing steel plate.

[0040] Furthermore, the pressing motor presses down, squeezing the copper foil against the first pressing steel plate, so that excess adhesive overflowing from the prepreg passes through the first overflow hole. This includes: driving the pressing motor to rotate forward, and the cover plate squeezing the first pressing steel plate through multiple kraft paper sheets. In this embodiment, the pressing motor works in conjunction with the first pressing steel plate. Specifically, the pressing motor pushes the first pressing steel plate to squeeze the copper foil, thereby pressing the copper foil and the fusion layer together to form a circuit board. During the pressing process, as the pressing motor presses down, the first pressing steel plate squeezes the copper foil towards the second pressing steel plate. The first overflow hole on the first pressing steel plate squeezes out excess adhesive from the prepreg, facilitating the guidance of excess adhesive during the lamination process of the multilayer circuit board onto the first pressing steel plate, thus facilitating the cleaning of excess adhesive. Before lamination, the copper foil and the fusion layer have through holes or gaps corresponding to the fusion layer. For example, the formed multilayer circuit board is a double-sided aluminum substrate or a copper-embedded plate. The excess adhesive flows from the through holes or gaps to the first excess adhesive hole. By driving the lamination motor to rotate forward, the lifting shaft of the lamination motor moves the cover plate so that the cover plate moves toward the kraft paper. This causes the cover plate to press the first lamination steel plate through the kraft paper, thereby causing the first lamination steel plate to press the copper foil and the fusion layer together, facilitating stable lamination of the copper foil and the fusion layer.

[0041] Furthermore, the driving pressing motor rotates forward, and the cover plate presses the first pressing steel plate through multiple kraft paper sheets. This is followed by pressing the fusion layer through the first and second pressing steel plates to squeeze excess adhesive from the fusion layer through the first excess adhesive hole to the space between the first pressing steel plate and the kraft paper. In this embodiment, the pressing motor works in conjunction with the first pressing steel plate. Specifically, the pressing motor pushes the first pressing steel plate to press the copper foil, thereby pressing the copper foil and the fusion layer together to form a circuit board. During the pressing process, as the first pressing steel plate presses the copper foil towards the second pressing steel plate, the first excess adhesive hole on the first pressing steel plate squeezes out excess adhesive from the prepreg, facilitating the guidance of excess adhesive during the multilayer circuit board pressing process onto the first pressing steel plate, thus facilitating the cleaning of excess adhesive. Before lamination, the copper foil and the fusion layer have through holes or gaps corresponding to the fusion layer. For example, the formed multilayer circuit board is a double-sided aluminum substrate or a copper-embedded plate. The excess adhesive flows from the through holes or gaps to the first excess adhesive hole. By driving the lamination motor to rotate forward, the lifting shaft of the lamination motor moves the cover plate so that the cover plate moves towards the kraft paper. This causes the cover plate to press the first lamination steel plate through the kraft paper, thereby causing the first lamination steel plate and the second lamination steel plate to jointly press the copper foil and the fusion layer. This facilitates the extrusion of excess adhesive in the fusion layer, and thus facilitates the extrusion of excess adhesive through the first excess adhesive hole. This allows the excess adhesive to be squeezed between the first lamination steel plate and the kraft paper, so that the excess adhesive adheres to the first lamination steel plate for easy cleaning.

[0042] Furthermore, the upward movement of the pressing motor to detach the first pressing steel plate with excess adhesive from the copper foil includes: reversing the pressing motor to lift the cover plate away from the kraft paper; and removing the first pressing steel plate and the kraft paper thereon. In this embodiment, the pressing motor works in conjunction with the first pressing steel plate. Specifically, the pressing motor pushes the first pressing steel plate to press the copper foil, thereby pressing the copper foil and the fusion layer together to form a circuit board. During the downward pressing process, as the first pressing steel plate presses the copper foil towards the second pressing steel plate, the first excess adhesive hole on the first pressing steel plate squeezes out excess adhesive from the prepreg, facilitating the guidance of excess adhesive during the multilayer circuit board pressing process onto the first pressing steel plate, thus facilitating the cleaning of excess adhesive. Before lamination, the copper foil and the fusion layer have through holes or gaps corresponding to the fusion layer. For example, the formed multilayer circuit board is a double-sided aluminum substrate or a copper-embedded plate. The excess adhesive flows from the through holes or gaps to the first excess adhesive hole. During the lifting process of the lamination motor, that is, when the cover plate moves away from the second lamination steel plate, the excess adhesive on the prepreg is squeezed out through the first excess adhesive hole, so that the excess adhesive accumulates between the first lamination steel plate and the kraft paper. This facilitates the adhesion of the excess adhesive during the lamination process of the multilayer circuit board to the first lamination steel plate, and also ensures that as much excess adhesive as possible is adhered to the side of the first lamination steel plate away from the second lamination steel plate, effectively improving the amount of excess adhesive removed.

[0043] In one embodiment, before placing multiple copper foils and multiple fusion layers onto the second pressing steel plate, the method further includes stacking multiple sheets of kraft paper on a pressing support plate. In this embodiment, the second pressing steel plate is placed on the kraft paper, and the kraft paper supports the second pressing steel plate on the pressing support plate, thus providing support and cushioning for the second pressing steel plate. The pressing of the first pressing steel plate and the second pressing steel plate is achieved under the drive of the pressing motor. Before pressing, multiple sheets of kraft paper are placed under the second pressing steel plate to ensure that the force exerted by the pressing motor on the second pressing steel plate is balanced, facilitating the complete pressing of the copper foils and fusion layers, thereby improving the pressing stability of the copper foils and fusion layers.

[0044] Furthermore, the second pressing steel plate has a second overflow hole; the driving pressing motor presses down, squeezing the copper foil with the first pressing steel plate, so that the overflowing adhesive from the prepreg passes through the first overflow hole, including: squeezing the fusion layer with the first and second pressing steel plates to squeeze the overflowing adhesive in the fusion layer from the second overflow hole to between the second pressing steel plate and the kraft paper. In this embodiment, the pressing motor works in conjunction with the first and second pressing steel plates. Specifically, the pressing motor pushes the first pressing steel plate, and together with the second pressing steel plate, squeezes the copper foil, thereby pressing the copper foil and the fusion layer to form a circuit board. During the pressing process, that is, the first pressing steel plate squeezes the copper foil towards the second pressing steel plate, and the second overflow hole on the second pressing steel plate squeezes out the excess overflowing adhesive on the prepreg, which facilitates guiding the overflowing adhesive during the pressing process of the multilayer circuit board to between the second pressing steel plate and the corresponding kraft paper, thereby further facilitating the cleaning of the overflowing adhesive.

[0045] During the actual lamination process of the copper foil and the fusion layer, the first lamination steel plate serves as the main cleaning steel plate for excess adhesive. Specifically, the first lamination steel plate, through its first excess adhesive hole, drains excess adhesive from the prepreg during lamination. Ultimately, excess adhesive forms on the side of the first lamination steel plate facing away from the prepreg, facilitating cleaning and preventing it from adhering to the copper foil surface. However, for different multilayer circuit boards, the positions of the through-holes on the copper foil vary, which can lead to different distances for the excess adhesive to reach the first excess adhesive hole. This can result in a slower overflow rate for some adhesive, potentially causing some excess adhesive to remain on the copper foil.

[0046] To increase the amount of adhesive overflow, the driving pressing motor presses down, squeezing the copper foil against the first pressing steel plate, so that the adhesive overflowing from the prepreg passes through the first overflow hole. This is preceded by the following steps:

[0047] Obtain an image of the pressed surface of the copper foil;

[0048] The pore coordinates of the copper foil are obtained from the image of the pressed surface;

[0049] The coordinates of the first overflow hole in the first press-fit steel plate are obtained based on the pore coordinates.

[0050] Replace the two adjacent magnetic core plates on the first pressing steel plate that correspond to the coordinates of the first overflow hole. The edges of the two adjacent magnetic core plates are respectively provided with overflow half holes, and the two overflow half holes form the first overflow hole.

[0051] In this embodiment, the copper foil serves as the outer layer of the multilayer circuit board, and has corresponding holes. For example, if the multilayer circuit board is a double-sided aluminum substrate, the holes on the copper foil are through-holes connecting the upper and lower circuit layers; or if the multilayer circuit board is a copper-embedded board, the holes on the copper foil are gaps for embedding copper blocks. The holes on the copper foil serve as outlets for excess adhesive in the prepreg. By acquiring images of the pressed surface of the copper foil, the coordinates of the holes on the copper foil can be accurately obtained, thus facilitating the determination of the specific location where the excess adhesive overflows from the copper foil, and further facilitating the determination of the coordinates of the holes in the copper foil, i.e., the hole coordinates. After obtaining the hole coordinates, the first excess adhesive hole needs to be located on the first pressing steel plate, and the hole coordinates need to be converted into coordinates on the first pressing steel plate to determine the coordinates on the first pressing steel plate corresponding to the hole, thereby facilitating the determination of the coordinates of the first excess adhesive hole on the first pressing steel plate. Finally, after determining the coordinates of the first overflow hole, the structure of the first pressed steel plate is modified. Specifically, the first pressed steel plate includes multiple spliced ​​magnetic core steel plates, and the sides of the magnetic core steel plates have overflow half-holes. By replacing the magnetic core steel plates, two adjacent magnetic core steel plates with overflow half-holes corresponding to the coordinates of the first overflow hole are selected. This facilitates the formation of a first overflow hole aligned with the pores of the copper foil at a designated position on the first pressed steel plate. This ensures that the first overflow hole and the pores of the copper foil are located at the same center, thereby reducing the distance the overflow adhesive needs to travel from the pores of the copper foil to the first overflow hole, allowing more adhesive to overflow and effectively increasing the amount of overflow adhesive. In another embodiment, two adjacent magnetic core steel plates are connected by two opposite magnets, i.e., adjacent magnetic core steel plates are magnetically attracted to each other.

[0052] Furthermore, the step of placing multiple copper foils and multiple fusion layers onto the second lamination steel plate further includes the following steps:

[0053] The core board of the fusion layer is subjected to first-edge copper treatment to obtain the core board with multiple staggered first-edge copper protrusions formed on the edge, so as to form a dotted glue flow groove between two adjacent first-edge copper protrusions.

[0054] In this embodiment, when the first and second pressing steel plates are pressed together, the core plate and the prepreg are squeezed and move towards each other, causing the prepreg to spread and cover the surface of the core plate with plastic, thereby improving the adhesion of the core plate in the multilayer circuit board. Some of the adhesive in the prepreg is excess and moves towards the edge of the core plate. To contain this excess adhesive, the core plate of the fusion layer undergoes a first-edge copper treatment, forming multiple staggered first-edge copper protrusions at the edge of the core plate. These protrusions do not contact each other at the edge of the core plate, creating gaps between them. This facilitates the collection of excess adhesive from the prepreg within the dotted adhesive channels formed between the protrusions, improving the containment effect of the excess adhesive. Furthermore, during the process of adhesive overflow flowing into the dot-type adhesive flow channel, the dot-type adhesive flow channel formed by multiple first-side copper protrusions has multiple flow directions. That is, the flow direction of the adhesive overflow between the multiple first-side copper protrusions is multiple, making the flow of adhesive overflow in the dot-type adhesive flow channel easily blocked by the first-side copper protrusions, thereby slowing down the flow of adhesive overflow and preventing the adhesive overflow from flowing out of the core board too quickly, effectively confining the adhesive overflow within the dot-type adhesive flow channel. In another embodiment, the first-side copper protrusion has a circular structure. For example, the first-side copper protrusion is a circular PAD with a diameter of 1.15mm to 1.36mm and a spacing of 0.4mm to 0.6mm between two adjacent circular PADs; or, for example, the diameter of the circular PAD is 1.25mm and the spacing between two adjacent circular PADs is 0.5mm.

[0055] Furthermore, the core board of the fusion layer undergoes a first-edge copper treatment to obtain a core board with multiple staggered first-edge copper protrusions formed on the edge, so as to form a dotted glue flow groove between two adjacent first-edge copper protrusions. This is followed by the following steps:

[0056] The core board of the fusion layer is subjected to a second-edge copper treatment to obtain the core board with multiple staggered second-edge copper protrusions formed on the edge, wherein the second-edge copper protrusions are disposed away from the first-edge copper protrusions.

[0057] In this embodiment, during the pressing of the first and second pressing steel plates, the core plate and the prepreg are compressed and move towards each other, causing them to adhere to each other. This allows the plastic on the prepreg to diffuse, covering the surface of the core plate with plastic, thereby improving the adhesion of the core plate in the multilayer circuit board. However, the core plate also contains some thin copper sheets, which are prone to warping during pressing, potentially leading to substandard quality in the multilayer circuit board. To reduce the warping probability, a second-edge copper treatment is applied to the core plate of the fusion layer. This creates multiple staggered second-edge copper protrusions on the edge of the core plate. These protrusions eliminate stress on the edge copper of the core plate, reducing edge stress and thus mitigating edge warping, effectively lowering the warping probability of the multilayer circuit board.

[0058] In another embodiment, the second copper protrusion has a "+" shaped structure, as in Embodiment 1.

[0059] In other embodiments, the second copper protrusion has a rhomboid structure, as in Embodiment Two; and the second copper protrusion simultaneously has both " / " and "+" shaped structures, as in Embodiment Three. For details regarding the board edge conditions corresponding to the above three embodiments, please refer to... Figure 2 Among them, the residual copper ratio and warpage of the second copper protrusion in Example 1 are significantly better than those in the other two examples.

[0060] In one embodiment, this application also provides a multilayer circuit board laminating device, the multilayer circuit board laminating device comprising: a laminating support plate and a board laminating assembly; the board laminating assembly comprising a first laminating steel plate, a second laminating steel plate and a laminating motor, the second laminating steel plate being disposed on the laminating support plate, the second laminating steel plate being used to place multiple copper foils and multiple fusion layers, the lifting shaft of the laminating motor being connected to the first laminating steel plate to move the first laminating steel plate away from or close to the second laminating steel plate, wherein the fusion layer comprises an interconnected core board and a prepreg, the first laminating steel plate having a first overflow hole for overflowing the adhesive in the prepreg. In this embodiment, when the copper foil and the fusion layer are pressed together by the first and second pressing steel plates, the prepreg is squeezed and there is excess adhesive, i.e., overflow adhesive. The first overflow hole discharges the overflow adhesive, allowing it to overflow between the first and second pressing steel plates. This allows the overflow adhesive to be squeezed out quickly, making it easy to remove the overflow adhesive and avoid forming adhesive residue on the copper foil with circuits, thereby reducing the probability of short circuits in the multilayer circuit board.

[0061] In one embodiment, this application also provides a multilayer circuit board, which is prepared using the multilayer circuit board lamination method described in any of the above embodiments. In this embodiment, the multilayer circuit board lamination method includes: laminating a multilayer circuit board using a multilayer circuit board lamination device, the multilayer circuit board lamination device including: a lamination support plate and a board lamination assembly; the board lamination assembly including a first lamination steel plate, a second lamination steel plate and a lamination motor, the second lamination steel plate being disposed on the lamination support plate, the second lamination steel plate being used to place multiple copper foils and multiple fusion layers, the lifting shaft of the lamination motor being connected to the first lamination steel plate to move the first lamination steel plate away from or closer to the second lamination steel plate, wherein the fusion layer includes an interconnected core board and a prepreg, and the first lamination steel plate having a first overflow hole; the multilayer circuit board lamination method includes: placing multiple copper foils and multiple fusion layers on the second lamination steel plate; driving the lamination motor downward to press the first lamination steel plate against the copper foil, so that the overflow adhesive from the prepreg passes through the first overflow hole; driving the lamination motor upward to detach the first lamination steel plate with the overflow adhesive from the copper foil. When the copper foil and fusion layer are pressed together by the first and second pressing steel plates, the prepreg is squeezed and there is excess glue, i.e., overflow glue. The first overflow glue hole guides the overflow glue, so that the overflow glue overflows from between the first and second pressing steel plates, thereby making the overflow glue squeezed out quickly, which is convenient to clean up the overflow glue and avoids the formation of glue residue on the copper foil with circuits, thereby reducing the probability of short circuits in the multilayer circuit board.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A multilayer wiring board lamination pressing method characterized by comprising: include: A multilayer circuit board laminating device is used to laminate multilayer circuit boards. The multilayer circuit board laminating device includes: Pressed bearing plate, A plate pressing assembly includes a first pressing steel plate, a second pressing steel plate, and a pressing motor. The second pressing steel plate is disposed on the pressing support plate and is used to place multiple copper foils and multiple fusion layers. The lifting shaft of the pressing motor is connected to the first pressing steel plate to move the first pressing steel plate away from or closer to the second pressing steel plate. The fusion layer includes an interconnected core plate and a prepreg. The first pressing steel plate has a first overflow hole. The multilayer circuit board lamination method includes: Multiple copper foils and multiple fusion layers are placed on a second press-fit steel plate; The driving pressing motor presses down, squeezing the copper foil by the first pressing steel plate, so that the overflowing adhesive in the prepreg passes through the first overflow hole; The drive pressing motor is lifted to separate the first pressing steel plate, which is covered with excess adhesive, from the copper foil; The process includes the following steps: The driving pressing motor presses down to squeeze the copper foil against the first pressing steel plate, so that the overflow adhesive from the prepreg passes through the first overflow hole. Obtain an image of the pressed surface of the copper foil; The pore coordinates of the copper foil are obtained from the image of the pressed surface; The coordinates of the first overflow hole of the first press-fit steel plate are obtained based on the pore coordinates. Replace the two adjacent magnetic core steel plates on the first pressing steel plate that correspond to the coordinates of the first overflow hole. The edges of the two adjacent magnetic core steel plates are respectively provided with overflow half holes, and the two overflow half holes form the first overflow hole. The step of placing multiple copper foils and multiple fusion layers onto the second lamination steel plate includes the following steps: The core board of the fusion layer is subjected to first-edge copper treatment to obtain the core board with multiple staggered first-edge copper protrusions formed on the edge, so as to form a dotted glue flow groove between two adjacent first-edge copper protrusions.

2. The multilayer wiring board lamination board method according to claim 1, characterized by, The step of placing multiple copper foils and multiple fusion layers on a second press-fit steel plate includes: Multiple copper foils and multiple fusion layers are sequentially and alternately stacked on the second press-fit steel plate.

3. The multilayer wiring board lamination board method according to claim 1, characterized by, The process of placing multiple copper foils and multiple fusion layers onto a second press-fit steel plate further includes: Multiple sheets of kraft paper are stacked on the side of the first pressing steel plate away from the copper foil.

4. The multilayer wiring board lamination board method according to claim 3, characterized by, The step of stacking multiple kraft papers on the side of the first pressing steel plate away from the copper foil further includes: A cover plate is placed on the side of the kraft paper facing away from the first pressing steel plate, wherein the cover plate is fixedly connected to the lifting shaft of the pressing motor.

5. The multilayer wiring board lamination board method according to claim 4, characterized by, The driving pressing motor presses down, squeezing the copper foil against the first pressing steel plate, so that the overflow adhesive from the prepreg passes through the first overflow hole, including: The drive pressing motor rotates forward, and the cover plate presses the first pressing steel plate through multiple kraft paper sheets.

6. The multilayer wiring board lamination board method according to claim 5, characterized by, The drive pressing motor rotates forward, and the cover plate presses the first pressing steel plate through multiple kraft paper sheets, followed by: The fusion layer is pressed together by the first and second pressing steel plates to squeeze the excess glue in the fusion layer out from the first excess glue hole to the space between the first pressing steel plate and the kraft paper.

7. The multilayer wiring board lamination board method according to claim 6, characterized by, The upward movement of the drive pressing motor, which removes the first pressing steel plate with excess adhesive from the copper foil, includes: The drive pressing motor reverses to lift the cover plate away from the kraft paper; Remove the first pressed steel plate and the kraft paper on it.

8. The multilayer wiring board lamination board method according to claim 1, characterized by, The process of placing multiple copper foils and multiple fusion layers on the second pressing steel plate further includes: Multiple kraft paper sheets are stacked on the pressing support plate.

9. The multilayer wiring board lamination board method according to claim 8, characterized by, The second pressing steel plate has a second overflow hole; the driving pressing motor presses down to squeeze the copper foil from the first pressing steel plate so that the overflow adhesive from the prepreg passes through the first overflow hole, including: The fusion layer is pressed together by the first and second pressing steel plates to squeeze the excess adhesive in the fusion layer out through the second excess adhesive hole to the space between the second pressing steel plate and the kraft paper.

10. A multilayer wiring board, characterized by, It is prepared using the multilayer circuit board lamination method as described in any one of claims 1 to 9.

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