High-heat-dissipation circuit board with embedded heat dissipation piece and preparation method of high-heat-dissipation circuit board

Abstract

The invention provides a high-heat-dissipation circuit board with an embedded heat dissipation piece and a preparation method of the high-heat-dissipation circuit board. The preparation method of the high-heat-dissipation circuit board comprises the following steps: stacking the substrate, the core plate and the prepreg, and then carrying out first-time lamination treatment; the substrate, the core plate and the prepreg are stacked and then subjected to first-time pressing treatment; carrying out routing processing on the multilayer board so as to form a through hole windowing area on the multilayer board; carrying out first-time attaching treatment on the multilayer board so as to enable the first barrier piece to cover the surface of the multilayer board; carrying out trepanning treatment on the first blocking piece so as to form a glue flowing hole in the first blocking piece; the heat dissipation module is placed in the through hole windowing area; carrying out second-time attaching treatment on the multi-layer board so as to enable the second barrier piece to cover one side face, far away from the first barrier piece, of the multi-layer board; the buffer layer, the gummosis layer and the multi-layer board are subjected to second-time pressing treatment; and carrying out separation treatment on the multi-layer board, so that the first barrier and the second barrier are separated from the surface of the multi-layer board.

Description

Technical Field

[0001] The present disclosure relates to the field of circuit boards, and in particular to a high heat dissipation circuit board with a built-in heat dissipation element and a preparation method of the high heat dissipation circuit board. Background Art

[0002] As automotive lighting technology rapidly develops towards high power and high density, the thermal management problem of LED modules has become increasingly prominent, and the thermal conductivity of the printed circuit board (PCB), which is its core support, faces higher requirements. In traditional solutions, although ordinary FR4 substrates can achieve low-cost heat dissipation through dense PTH thermal via arrays, their thermal conductivity can hardly meet the needs of high-power LEDs; and metal substrates (such as aluminum substrates and copper substrates) have excellent thermal conductivity, but they have shortcomings such as high cost and limited design flexibility.

[0003] In order to solve the above problems, in recent years, embedded heat dissipation technology based on double-sided or multi-layer FR4 has gradually become a new trend in the industry. By embedding new structures such as copper blocks or ceramic copper-clad plates in PCBs, the thermal conductivity is effectively improved and the design flexibility is taken into account, providing an innovative solution for the heat dissipation problem of high-power headlights. For example, Chinese patent application number 201810929978.4 discloses a heat dissipation substrate and a preparation method thereof, which improves the heat dissipation performance of the circuit board by opening a window in an insulating substrate and embedding a ceramic heat dissipation component. Another example is Chinese patent application number 201780000036.1. It discloses an IGBT module and a manufacturing method thereof, which improves the heat dissipation performance of the circuit board by opening a window on the heat dissipation substrate and embedding a ceramic heat sink. During the lamination process of the multilayer boards of the above-mentioned patent, the PP glue of the semi-cured sheets between the multilayer boards flows into the window area during hot pressing to fix the heat sink and the multilayer boards. However, the PP glue easily overflows from the window to the copper foil on the surface, causing glue flow problems, especially in the window with a through-hole structure. The PP glue adhered to the copper foil surface requires a lot of time to clean, resulting in low production efficiency. In addition, if the overflow glue on the copper foil surface is not completely removed, it is easy to cause the risk of short circuit in the subsequent production of graphic circuits.

[0004] Therefore, there is an urgent need for a circuit board with an embedded heat sink and a preparation method thereof that can avoid glue flow on the copper foil surface and improve production efficiency. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high heat dissipation circuit board with an embedded heat sink and a method for preparing the high heat dissipation circuit board, which can avoid glue flow on the copper foil surface and improve production efficiency.

[0006] The purpose of this disclosure is achieved through the following technical solutions:

[0007] A method for preparing a high heat dissipation circuit board comprises the following steps:

[0008] Stack the substrate, core board and prepreg, and then perform the first lamination process to form a multilayer board;

[0009] Perform routing on the multilayer board so that the multilayer board has a via opening area;

[0010] Perform the first attachment process on the multilayer board so that the first barrier covers the surface of the multilayer board;

[0011] Perform hole opening on the first barrier so that the first barrier has glue flow holes, and the glue flow holes communicate with the via opening area;

[0012] Place the heat dissipation module in the via opening area;

[0013] Perform the second attachment process on the multilayer board so that the second barrier covers the side of the multilayer board away from the first barrier;

[0014] Perform the second lamination process on the buffer layer, glue flow layer and multilayer board so that the glue flow layer melts and enters the via opening area through the glue flow holes to fix the heat dissipation module to the multilayer board;

[0015] Perform separation on the multilayer board so that the first barrier and the second barrier are separated from the surface of the multilayer board.

[0016] In one embodiment, performing the second lamination on the buffer layer, glue flow layer and multilayer board specifically includes the following steps:

[0017] Stack the buffer layer and the glue flow layer on the first barrier, and the glue flow layer is located between the buffer layer and the first barrier;

[0018] Perform the second lamination on the buffer layer, glue flow layer and multilayer board under high temperature and high pressure so that the glue flow layer melts and enters the via opening area through the glue flow holes.

[0019] In one embodiment, before placing the heat dissipation module in the via opening area, the following steps are further included:

[0020] Perform film pasting on the heat dissipation module so that a partial area of the heat dissipation module adjacent to the glue flow hole is covered with a barrier film.

[0021] In one embodiment, after performing film pasting on the heat dissipation module, the following steps are further included:

[0022] Perform cutting on the heat dissipation module so that the surface of the heat dissipation module is rough.

[0023] In one embodiment, the first barrier member is a polyimide film; and / or,

[0024] the second barrier member is a polyimide film.

[0025] In one embodiment, opening holes in the first barrier member specifically includes the following steps:

[0026] Using a laser to ablate the first barrier member so that the first barrier member forms the glue flow holes.

[0027] In one embodiment, before routing the multilayer board, the following steps are further included:

[0028] Drilling the multilayer board to form positioning holes.

[0029] In one embodiment, after separating the multilayer board, the following steps are further included:

[0030] Performing a grinding process on the multilayer board.

[0031] In one embodiment, the separating process of the multilayer board specifically includes the following steps:

[0032] Performing a tearing operation on the first barrier member, the glue flow layer and the buffer layer to separate the first barrier member from the multilayer board;

[0033] Performing a tearing operation on the second barrier member to separate the second barrier member from the multilayer board.

[0034] A high heat dissipation circuit board with an embedded heat dissipation member is prepared by using the preparation method of the high heat dissipation circuit board described in any of the above embodiments. The high heat dissipation circuit board includes at least one core board, two substrate boards, prepregs and a heat dissipation module. The core board is located between the two substrate boards. The prepregs are sandwiched between the core board and the substrate boards to fix the substrate boards and the core board. The substrate boards, the core board and the prepregs jointly form the via opening area. The heat dissipation module is located in the via opening area, and the heat dissipation module is fixed to the substrate boards, the core board and the prepregs respectively through an adhesive layer.

[0035] Compared with the prior art, the present disclosure has at least the following advantages:

[0036] In the preparation method of the above high heat dissipation circuit board, after the first lamination of the substrate, the core board and the prepreg, the substrate and the core board are fixed by the flowing glue of the prepreg to form a multilayer board. Then, the multilayer board is routed to form a via window area. Then, a first barrier member and a second barrier member are attached to both sides of the multilayer board respectively. The first barrier member is provided with a flowing glue hole, and the flowing glue hole is communicated with the via window area. The heat dissipation module is embedded in the via window area, so that both ends of the heat dissipation module are abutted against the first barrier member and the second barrier member respectively. The buffer layer and the flowing glue layer are stacked on the first barrier member in sequence and subjected to a second lamination treatment. Under the state of high temperature and high pressure, the flowing glue layer melts into a fluid state and passes through the flowing glue hole into the via window area, so that the gap between the heat dissipation module and the multilayer board is filled with the flowing glue layer. And because the first barrier member and the second barrier member are attached to both sides of the multilayer board respectively, the flowing glue layer cannot overflow onto the copper foil on the surface of the multilayer board, thus avoiding the need to spend a lot of time cleaning the overflowing glue on the copper foil surface in the subsequent process, improving the production efficiency, and at the same time avoiding the short circuit problem caused by incomplete removal of the copper foil surface, further improving the yield of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 is a process flow chart of the preparation method of the high heat dissipation circuit board according to an embodiment;

[0039] Figure 2 is adopted Figure 1 is a schematic structural diagram of a high heat dissipation circuit board with an embedded heat dissipation member prepared by the preparation method of the high heat dissipation circuit board shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present disclosure more thorough and comprehensive.

[0041] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this disclosure pertains. The terms used in the specification of this disclosure herein are only for the purpose of describing specific implementations and are not intended to limit this disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0043] This disclosure provides a method for preparing a high heat dissipation circuit board, including the following steps: stacking a substrate, a core board and a prepreg and then performing a first lamination process to form a multilayer board; stacking the substrate, the core board and the prepreg and then performing a first lamination process to form a multilayer board; performing a routing process on the multilayer board to form a via opening area on the multilayer board; performing a first attaching process on the multilayer board to cover a first barrier on the surface of the multilayer board; performing an opening process on the first barrier to form a glue flow hole in the first barrier, and the glue flow hole communicates with the via opening area; placing a heat dissipation module in the via opening area; performing a second attaching process on the multilayer board to cover a second barrier on the side of the multilayer board away from the first barrier; performing a second lamination process on the buffer layer, the glue flow layer and the multilayer board to melt the glue flow layer and make it enter the via opening area from the glue flow hole to fix the heat dissipation module to the multilayer board; performing a separation process on the multilayer board to separate the first barrier and the second barrier from the surface of the multilayer board.

[0044] In the preparation method of the above high heat dissipation circuit board, after the first lamination of the substrate, the core board and the prepreg, the substrate and the core board are fixed by the flowing glue of the prepreg to form a multilayer board. Then, the multilayer board is routed to form a via window area. Then, a first barrier member and a second barrier member are respectively attached to both sides of the multilayer board. The first barrier member is provided with a flowing glue hole, and the flowing glue hole is communicated with the via window area. The heat dissipation module is embedded in the via window area, so that both ends of the heat dissipation module are respectively abutted against the first barrier member and the second barrier member. The buffer layer and the flowing glue layer are sequentially stacked on the first barrier member and subjected to a second lamination process. Under the state of high temperature and high pressure, the flowing glue layer melts into a fluid state and passes through the flowing glue hole into the via window area, so that the gap between the heat dissipation module and the multilayer board is filled with the flowing glue layer. And because the first barrier member and the second barrier member are respectively attached to both sides of the multilayer board, the flowing glue layer cannot overflow onto the copper foil on the surface of the multilayer board, thereby avoiding the need to spend a lot of time cleaning the overflowing glue on the copper foil surface in the subsequent process, thus improving the production efficiency. At the same time, it also avoids the short circuit problem caused by incomplete removal of the copper foil surface, further improving the yield of the product.

[0045] To better understand the technical solutions and beneficial effects of the present disclosure, the following further describes the present disclosure in detail with specific embodiments:

[0046] As Figure 1 and Figure 2 shown, the preparation method of the high heat dissipation circuit board of an embodiment includes the following steps:

[0047] S100: Stack the substrate 100, the core board 200 and the prepreg 300 and perform the first lamination process to form a multilayer board. In this embodiment, after the core board 200 and the substrate 100 are cut, inner layer circuit etching is performed so that the circuits are conducted after the core board 200 and the substrate 100 are laminated. Then, the substrate 100, the core board 200 and the prepreg 300 are sequentially stacked and subjected to the first lamination process, that is, at least one core board 200 is located between two substrates 100, and a prepreg 300 is placed between the core board 200 and the substrate 100. Under high temperature and high pressure, the glue layer of the prepreg 300 melts and fills into the substrate 100 and the core board 200, so that the substrate 100 and the core board 200 are fixed to form a multilayer board. Further, the number of core boards 200 can be increased between two substrates 100 according to design requirements to form high-layer multilayer boards such as six-layer boards and eight-layer boards.

[0048] S200: Perform routing on the multi-layer board so that the multi-layer board forms a via opening area. In this embodiment, a routing machine is used to route the multi-layer board, so that the multi-layer board forms a via opening area, which is used to embed the heat dissipation module 400. The diameter of the via opening area is larger than the diameter of the heat dissipation module 400, so that there is a small gap between the wall of the via opening area and the heat dissipation module 400, so that the glue can flow into the gap.

[0049] S300: Perform the first attachment process on the multi-layer board so that the first barrier 500 covers the surface of the multi-layer board. In this embodiment, the first barrier 500 is attached to the surface of the multi-layer board, that is, the copper foil on the surface of the multi-layer board is covered by the first barrier 500. In this way, when the second lamination is performed, even if the glue in the via opening area overflows, it will be blocked by the first barrier 500, thus preventing the copper foil on the surface of the multi-layer board from being stained with the overflowing glue.

[0050] S400: Perform an opening process on the first barrier 500 so that the first barrier 500 forms a glue flow hole 510, and the glue flow hole 510 communicates with the via opening area. In this embodiment, after the first barrier 500 is opened, a glue flow hole 510 is formed. The glue flow hole 510 is correspondingly arranged with the via opening area and communicates with the via opening area, so as to facilitate the glue flow layer 600 to enter the via opening area from the glue flow hole 510, and further fix the heat dissipation module 400 to the multi-layer board through the glue.

[0051] S500: Place the heat dissipation module 400 in the via opening area. In this embodiment, after the first barrier 500 is attached to one surface of the multi-layer board, the heat dissipation module 400 is placed in the via opening area. Since the via opening area is adjacent to the position with a relatively high working temperature of the multi-layer board, when the finished circuit board is working, the heat is transferred to the heat dissipation module 400 in the via opening area. Due to the relatively high thermal conductivity of the heat dissipation module 400, the heat is dissipated at a high speed, improving the heat dissipation performance of the circuit board.

[0052] S600: Perform the second attachment process on the multi-layer board so that the second barrier 800 covers the side of the multi-layer board away from the first barrier 500. In this embodiment, after the heat dissipation module 400 is placed in the via opening area, the second attachment process is performed on the multi-layer board, that is, the second barrier 800 is covered on the side of the multi-layer board away from the first barrier 500. In this way, the heat dissipation module 400 in the via opening area is blocked by the first barrier 500 and the second barrier 800 to be fixed in the via opening area. At the same time, the copper foils on both sides of the multi-layer board are respectively blocked by the first barrier 500 and the second barrier 800. When the second lamination is performed, even if the glue overflows, it cannot adhere to the copper foil on the surface of the multi-layer board, improving the product yield and production efficiency.

[0053] S700: The buffer layer 700, the glue flow layer 600 and the multi-layer board are subjected to a second lamination process, so that the glue flow layer 600 melts and enters the via window area from the glue flow holes 510, so as to fix the heat dissipation module 400 to the multi-layer board. In this embodiment, the buffer layer 700 and the glue flow layer 600 are sequentially stacked on the first barrier 500. The buffer layer 700 is used to abut against the acting end of the press, so that the multi-layer board is uniformly stressed. The glue flow layer 600 is located between the first barrier 500 and the buffer layer 700. Under the state of high temperature and high pressure, the glue flow layer 600 is in a flowing state and enters the via window area from the glue flow holes 510, so that the glue fills the gap between the multi-layer board and the heat dissipation module 400, and then the heat dissipation module 400 is fixed to the multi-layer board. Further, during the first lamination process of the prepreg 300 between the core board 200 and the substrate 100, the glue of the prepreg 300 has been bonded between the core board 200 and the substrate 100. That is, during the second lamination process, the glue in the via window area mainly flows in from one side of the glue flow layer 600, that is, from the glue flow holes 510. In this way, the amount of glue in the via window area is better controlled through the two lamination processes, and further the glue overflowing from the surface of the multi-layer board is avoided. Furthermore, the buffer layer 700 can be made of a thin copper foil, and the glue flow layer 600 can be made of PP glue.

[0054] S800: The multi-layer board is subjected to a separation process, so that the first barrier 500 and the second barrier 800 are separated from the surface of the multi-layer board. In this embodiment, after the glue flow layer 600 flows into the via window area, the heat dissipation module 400 is fixed to the multi-layer board. At this time, the first barrier 500 and the second barrier 800 on both sides of the multi-layer board need to be separated to facilitate the subsequent grinding of the multi-layer board surface. First, the glue flow layer 600 and the buffer layer 700 on the first barrier 500 are separated, then the first barrier 500 is torn off from the surface of the multi-layer board, and finally the second barrier 800 is torn off from the other side of the multi-layer board. Since the first barrier 500 and the second barrier 800 only cover the surface of the multi-layer board, that is, the first barrier 500 and the second barrier 800 are not bonded to the surface of the multi-layer board, the separation operation of the first barrier 500 and the second barrier 800 is convenient and will not damage the surface of the multi-layer board.

[0055] In the above method for preparing a high heat dissipation circuit board, after the first lamination of the substrate 100, the core board 200 and the prepreg 300, the substrate 100 and the core board 200 are fixed by the flowing glue of the prepreg 300 to form a multilayer board. Then, the multilayer board is routed to form a via opening area. Then, a first barrier member 500 and a second barrier member 800 are respectively attached to both sides of the multilayer board. The first barrier member 500 is provided with a flowing glue hole 510, and the flowing glue hole 510 communicates with the via opening area. The heat dissipation module 400 is embedded in the via opening area, so that both ends of the heat dissipation module 400 are respectively abutted against the first barrier member 500 and the second barrier member 800. The buffer layer 700 and the flowing glue layer 600 are sequentially stacked on the first barrier member 500 and a second lamination process is performed. Under the state of high temperature and high pressure, the flowing glue layer 600 melts into a fluid state and passes through the flowing glue hole 510 into the via opening area, so that the gap between the heat dissipation module 400 and the multilayer board is filled with the flowing glue layer 600. And because the first barrier member 500 and the second barrier member 800 are respectively attached to both sides of the multilayer board, the flowing glue layer 600 cannot overflow onto the copper foil on the surface of the multilayer board, thereby avoiding the need to spend a lot of time cleaning the overflowing glue on the copper foil surface in the subsequent process. In this way, the production efficiency is improved, and at the same time, the short circuit problem caused by incomplete removal of the copper foil surface is avoided, further improving the yield of the product.

[0056] In one embodiment, the second lamination of the buffer layer 700, the flowing glue layer 600 and the multilayer board specifically includes the following steps:

[0057] Stack the buffer layer 700 and the flowing glue layer 600 on the first barrier member 500, and the flowing glue layer 600 is located between the buffer layer 700 and the first barrier member 500;

[0058] Perform a second lamination on the buffer layer 700, the flowing glue layer 600 and the multilayer board under the state of high temperature and high pressure, so that the flowing glue layer 600 melts and enters the via opening area from the flowing glue hole 510.

[0059] In this embodiment, before the second lamination of the multilayer board, the glue flow layer 600 is placed on the first barrier member 500, and then the buffer layer 700 is placed on the glue flow layer 600, that is, the glue flow layer 600 is located between the buffer layer 700 and the multilayer board. The buffer layer 700 abuts against the press, and the buffer layer 700, the glue flow layer 600 and the multilayer board are subjected to the second lamination under high temperature and high pressure. At this time, the glue flow layer 600 melts and enters the via opening area through the glue flow holes 510 under the action of pressure. There is a small gap between the heat dissipation module 400 located in the via opening area and the multilayer board. The glue flow layer 600 in a flowing state fills the gap, so that the heat dissipation module 400 is fixed to the multilayer board. Further, since the single-side glue flow method is adopted, that is, the glue flow layer 600 can only flow in from one side of the glue flow holes 510 under high temperature and high pressure, and because there is the first barrier member 500 on the surface of the multilayer board, the glue flow layer 600 cannot contact the surface of the multilayer board, thus avoiding the problem of glue overflow on the surface of the multilayer board. Further, the pressure during the second lamination process is 300 psi - 400 psi, and the temperature is 180 °C - 210 °C.

[0060] In one of the embodiments, before placing the heat dissipation module 400 in the via opening area, the following steps are further included:

[0061] Film the heat dissipation module 400 so that a partial area of the heat dissipation module 400 adjacent to the glue flow holes 510 is covered with a barrier film.

[0062] It can be understood that before the heat dissipation module 400 is placed in the via opening area, the surface of the heat dissipation module 400 needs to be processed. This is because after the heat dissipation module 400 is placed in the via opening area, its surface is correspondingly arranged with the glue flow holes 510. In this way, the glue flow layer 600 will inevitably adhere to the surface of the heat dissipation module 400 close to the glue flow layer 600, that is, the top of the heat dissipation module 400. And the adhesion of the glue flow layer 600 on the surface of the heat dissipation module 400 will affect the heat dissipation performance of the heat dissipation module 400. Therefore, in this embodiment, before the heat dissipation module 400 is placed in the via opening area, the heat dissipation module 400 is filmed, that is, the barrier film is adhered to the top of the heat dissipation module 400. In this way, during the second lamination process, even if the glue flow layer 600 passes through the top of the heat dissipation module 400, it will be blocked by the barrier film, that is, the top of the heat dissipation module 400 will not be adhered with the glue flow layer 600. The glue flow layer 600 will flow into the gap between the periphery of the heat dissipation module 400 and the multilayer board. Finally, after the second lamination is completed, the barrier film is torn off from the top of the heat dissipation module 400, so that the heat dissipation performance of the heat dissipation module 400 is better.

[0063] In one of the embodiments, after filming the heat dissipation module 400, the following steps are further included:

[0064] Cut the heat dissipation module 400 to roughen the surface of the heat dissipation module 400.

[0065] In this embodiment, the heat dissipation module 400 after film pasting needs to be cut. By adjusting the parameters of the laser, the cutting speed is 0.9 m / Min, the current is 10 A, the focal length is 0.1 - 0.5, the auxiliary gas is air, and the air pressure > 15 kg / cm 2 , to perform laser cutting on the heat dissipation module 400. The overall unilateral size of the heat dissipation module 400 after cutting is 3 mil smaller than the through-hole windowing area, that is, the volume of the heat dissipation module 400 is slightly smaller than the volume of the through-hole windowing area, so that there is a small gap between the heat dissipation module 400 and the through-hole windowing area, facilitating the filling of the glue layer 600. And because of using laser cutting, the side surface of the heat dissipation module 400 after cutting is relatively rough, making the bonding force between the heat dissipation module 400 and the glue layer 600 better. In this way, the brownification operation of the heat dissipation module 400 is omitted, saving the time of the brownification process of the heat dissipation module 400 while ensuring a good bonding force between the heat dissipation module 400 and the glue layer 600.

[0066] In one embodiment, the first barrier 500 is a polyimide film. In this embodiment, the first barrier 500 uses a polyimide film, that is, a PI film. The PI film has high heat resistance and small pore size. The cast glue layer 600 cannot contact the surface of the multilayer board through the PI film under high temperature and high pressure, thus avoiding the problem of glue overflow on the surface of the multilayer board. At the same time, the PI film has extremely high heat resistance and can maintain stable performance in a high-temperature environment. Further, the bonding force between the PI film and the multilayer board is small, and after the second lamination is completed, the PI film is easily separated from the multilayer board. Further, in other embodiments, the first barrier 500 can also be other polymer films in the prior art.

[0067] In one embodiment, the second barrier 800 is a polyimide film. It can be understood that in other embodiments, the second barrier 800 can also be other polymer films in the prior art.

[0068] In one embodiment, the first barrier 500 is perforated, specifically in the following steps:

[0069] Use a laser to ablate the first barrier 500 to form the glue holes 510 in the first barrier 500.

[0070] In this embodiment, the first barrier 500 uses a PI film. A laser is used to ablate the first barrier 500 to form glue holes 510, so that the cast glue layer 600 can enter the through-hole windowing area from the glue holes 510 during the second lamination process, thereby fixing the heat dissipation module 400 to the multilayer board.

[0071] In one embodiment, before routing the multilayer board, the following steps are further included:

[0072] Drill the multilayer board to form positioning holes.

[0073] In this embodiment, before routing the multilayer board, the multilayer board is first drilled. That is, the equipment forms positioning holes on the multilayer board through a positioning target, so that positioning is performed through the positioning holes during the subsequent first lamination, routing, and second lamination processes, improving the accuracy of the process and further improving the product yield.

[0074] In one embodiment, after separating the multilayer board, the following steps are further included:

[0075] Perform a grinding process on the multilayer board.

[0076] It can be understood that during the manufacturing process of the multilayer board, there may be defects such as unevenness, non-uniformity, burrs, and stains on the surface due to mechanical processing such as cutting, drilling, or routing. These defects not only affect the appearance of the multilayer board but also have an adverse impact on subsequent processes (such as electroless copper plating, electroplating, welding, etc.). In this embodiment, the surface of the multilayer board is ground by a ceramic brush wheel to remove the defects on the plane of the multilayer board, making the surface of the multilayer board flat and smooth.

[0077] In one embodiment, the separation process of the multilayer board specifically includes the following steps:

[0078] Perform a tearing operation on the first barrier 500, the glue layer 600, and the buffer layer 700 to separate the first barrier 500 from the multilayer board;

[0079] Perform a tearing operation on the second barrier 800 to separate the second barrier 800 from the multilayer board.

[0080] In this embodiment, since the glue layer 600 is adhered to the heat dissipation module 400, the glue layer 600 and the buffer layer 700 are first torn off from the first barrier 500, and then the first barrier 500 is torn off from the multilayer board. Since the bonding force between the first barrier 500 and the multilayer board is small, the first barrier 500 can be easily torn off from the multilayer board. Finally, the second barrier 800 is torn off from the other side of the multilayer board to facilitate the subsequent processes of the multilayer board.

[0081] It can be understood that for a multi-layer board with a relatively high thickness (such as a 10-layer board), since the glue flow layer enters the via opening area in a single-sided glue flow manner. However, after the glue flow layer enters the via opening area, due to the relatively large thickness of the multi-layer board, there is air inside the multi-layer board, and the gap path between the multi-layer board and the heat dissipation module is complex. As a result, the greater the resistance the glue flow layer encounters as it penetrates deeper, there may be a problem that the glue flow layer is difficult to reach the bottom of the multi-layer board. Thus, there is no glue at the bottom of the heat dissipation module and the bottom of the multi-layer board, which further leads to a poor fixing effect between the heat dissipation module and the multi-layer board. In one implementation, to improve the fixing effect between the heat dissipation module and the multi-layer board, the buffer layer, the glue flow layer, and the multi-layer board are subjected to a second lamination process, which also includes the following steps before:

[0082] Obtain the thickness value of the multi-layer board;

[0083] Match the thickness value of the multi-layer board with a preset thickness;

[0084] When the thickness value of the multi-layer board is greater than or equal to the preset thickness, perform an opening process on the second barrier member so that the second barrier member forms an avoidance hole;

[0085] Stack the copper foil and the glue flow PP on the second barrier member, with the glue flow PP located between the copper foil and the second barrier member.

[0086] In this embodiment, first, the thickness value of the multi-layer board is detected to obtain the thickness of the multi-layer board, and then the thickness of the multi-layer board is matched with the preset thickness. The preset thickness is the standard thickness of the pre-designed multi-layer board, for example, 2.0 mm. When the thickness value of the multi-layer board is greater than or equal to the preset thickness, that is, when the thickness value of the multi-layer board is greater than 2.0 mm, it indicates that the thickness of the multi-layer board is relatively large at this time, and the single-sided glue flow method may not be able to completely penetrate to the bottom of the multi-layer board. Therefore, the second barrier member is opened to form an avoidance hole, and the avoidance hole is connected to the via opening area. Then, the copper foil and the glue flow PP are stacked on the surface of the second barrier member, with the glue flow PP located between the copper foil and the second barrier member. When the multi-layer board is subjected to the second lamination, since there is a glue flow layer on the upper side of the multi-layer board and glue flow PP on the lower side, the glue flow layer enters the via opening area through the glue flow hole, and the glue flow PP enters the via opening area through the avoidance hole, that is, glue flows in from both sides of the multi-layer board, making the gaps between the heat dissipation module and the multi-layer board filled with the glue flow layer and the glue flow PP respectively. Compared with the single-sided glue flow method, the double-sided glue flow is more suitable for multi-layer boards with a relatively high thickness.

[0087] Further, when the two sides of the press simultaneously heat and laminate the multilayer board, since the glue flow layers and the glue flow PP on both sides of the multilayer board are heated and melted, they respectively enter the through-hole opening area through the glue flow holes and the relief holes. However, due to the relatively high thickness of the multilayer board, that is, there is more air remaining in the gap between the through-hole opening area and the multilayer board, and it is difficult to discharge the air remaining in the middle during the lamination of both sides. As a result, the glue flow on both sides is difficult to reach the middle area, which further leads to an insufficiently stable fixation between the heat dissipation module and the multilayer board. Therefore, in one embodiment, the buffer layer, the glue flow layer, and the multilayer board are subjected to a second lamination process, which specifically includes the following steps:

[0088] Heat and laminate the glue flow layer to melt the glue flow layer into the through-hole opening area and allow air to flow out from the relief holes;

[0089] Simultaneously heat and laminate the glue flow layer and the glue flow PP to make the glue flow layer and the glue flow PP flow towards each other.

[0090] In this embodiment, first heat the glue flow layer. For example, the press heats the buffer layer (copper foil), and then the buffer layer transfers the heat to the glue flow layer, causing the glue flow layer to melt into a flowing state. Then, high-pressure lamination makes the glue flow layer enter the through-hole opening area through the glue flow holes. At this time, since the glue flow PP at the bottom is not heated, that is, the glue flow PP is still in a solid state, when the glue flow layer is subjected to high-pressure lamination, the air in the through-hole opening area can be discharged from the bottom relief holes after the glue flow layer enters the through-hole opening area, thereby reducing the air remaining in the through-hole opening area. Then, simultaneously heat and laminate the glue flow layer and the glue flow PP. That is, at this time, the glue flow PP is also heated and melted and enters the through-hole opening area from the relief holes under high pressure. Since the air in the through-hole opening area is discharged, the glue flow layer and the glue flow PP flow towards each other in the through-hole opening area and fill the gap between the multilayer board and the heat dissipation module, thereby ensuring the fixation effect of the heat dissipation module. Further, the heating and lamination time of the glue flow layer should be less than the heating and lamination time of the glue flow layer and the glue flow PP simultaneously. This is because during the heating and lamination process of the glue flow layer, the air can be quickly discharged from the relief holes, and it is also necessary to ensure that the glue flow layer that first flows into the through-hole opening area remains in a flowing state during the subsequent simultaneous heating and lamination of the glue flow layer and the glue flow PP, so that the gap between the heat dissipation module and the multilayer board can be better filled by the glue flow layer and the glue flow PP after the lamination ends.

[0091] It can be understood that, in order to achieve a better filling effect of the glue flow layer and the glue flow PP from both sides of the multilayer board, in one embodiment, the glue flow holes are annular, and the glue flow holes are arranged around the periphery of one side surface of the through-hole opening area. The number of the relief holes is multiple, and the multiple relief holes are arranged around the periphery of the other side surface of the through-hole opening area. The multiple relief holes together form a glue flow area, and the diameter of the glue flow area is smaller than the diameter of the glue flow holes. In this embodiment, the glue flow holes are located above the heat dissipation module and are annular. The multiple relief holes are located below the heat dissipation module, and the multiple relief holes are arranged around the periphery of the other side surface of the through-hole opening area. Moreover, the diameter of the glue flow area formed by the multiple relief holes is smaller than the diameter of the glue flow holes. That is, the path of the glue flow layer flowing into the through-hole opening area through the glue flow holes and the path of the glue flow PP flowing into the through-hole opening area through the relief holes are not in the same vertical plane, that is, the path of the glue flow layer flowing into the through-hole opening area through the glue flow holes and the path of the glue flow PP flowing into the through-hole opening area through the relief holes are staggered from each other. In this way, when the glue flow layer and the glue flow PP are pressed simultaneously, no mutual acting force is generated, making the paths for the glue flow layer and the glue flow PP to enter the through-hole opening area more complex, and further enabling the glue flow layer and the glue flow PP to better fill the gap between the heat dissipation module and the multilayer board.

[0092] Further, in order to facilitate the discharge of air in the via opening area, in one embodiment, the diameter of the relief hole gradually increases from the end close to the heat dissipation module to the end far from the heat dissipation module. In this embodiment, the diameter of the relief hole gradually increases from the end close to the heat dissipation module to the end far from the heat dissipation module, that is, the relief hole is in a horn shape. In this way, during the pre-lamination process of the glue flow layer, the air in the via opening area is squeezed and flows out from the relief hole, and the horn-shaped relief hole increases the volume of air circulation, which is more conducive to the discharge of air in the via opening area. During the lamination process of the glue flow PP at the bottom, the glue flow PP is heated and becomes a casting shape, and the casting-shaped glue flow PP is forced to flow towards the relief hole. The relief hole is in a horn shape, that is, the diameter of the relief hole gradually decreases from the end close to the glue flow PP to the end far from the glue flow PP. In this way, the glue flow PP converges at the relief hole and then flows into the via opening area. Under the same pressure, the travel of the glue flow PP to the via opening area is farther, so that the glue flow PP can better combine with the glue flow layer, and further the glue flow PP can better fill the gap between the multilayer board and the heat dissipation module. Further, the extrusion rate during the bottom lamination is lower than that during the top lamination, that is, the extrusion rate of the glue flow PP is less than that of the glue flow layer. This is because the glue flow layer at the top can flow downward due to its own gravity when passing through the glue flow hole, while the glue flow PP is extruded upward into the via opening area. By adjusting the extrusion rate of the glue flow PP to be relatively slow, such as the extrusion rate of the glue flow PP being half of the extrusion rate of the glue flow layer, in this way, the glue flow PP converges through the horn-shaped relief hole and then enters the via opening area, and further the glue flow PP fills the bottom gap between the multilayer board and the heat dissipation module more completely, so as to ensure a better fixing effect between the bottom of the heat dissipation module and the bottom of the multilayer board.

[0093] Such as Figure 2As shown in the figure, the present application also provides a highly heat-dissipating circuit board 10 with an embedded heat-dissipating component, which is prepared by using the preparation method of the highly heat-dissipating circuit board described in any of the above embodiments. The highly heat-dissipating circuit board includes at least one core board 200, two substrate boards 100, prepregs 300 and a heat-dissipating module 400. The core board 200 is located between the two substrate boards 100, and the prepregs 300 are clamped between the core board 200 and the substrate boards 100 to fix the substrate boards 100 and the core board 200. The substrate boards 100, the core board 200 and the prepregs 300 together form a via opening area. The heat-dissipating module 400 is located in the via opening area, and the heat-dissipating module 400 is fixed to the substrate boards 100, the core board 200 and the prepregs 300 respectively through an adhesive layer. It can be understood that two substrate boards 100 are used on both sides of the highly heat-dissipating circuit board of the present application, and at least one core board 200 is clamped between the two substrate boards 100 to form a multi-layer board. Compared with the multi-layer board formed by pressing the core board 200 in the prior art, the circuit board structure of the present application can reduce the use of the core board 200. For example, for a four-layer board, the present application forms a four-layer board by pressing a core board 200 clamped in the middle with substrate boards 100 on both sides, while in the prior art, two core boards 200 need to be pressed to form a four-layer board. The price of the core board 200 itself is relatively high, especially for high-performance materials (such as high-frequency materials), which will increase the overall cost. Moreover, higher process control capabilities are required for the pressing of multiple core boards 200, and the process is more complex. Therefore, the structure of the highly heat-dissipating circuit board of the present application can reduce the use of the core board 200 compared with the prior art, and at the same time the process is simpler. Further, by providing a via opening area on the multi-layer board and locating the heat-dissipating module 400 in the via opening area, the heat-dissipating performance of the multi-layer board is better.

[0094] Compared with the prior art, the present disclosure has at least the following advantages:

[0095] In the preparation method of the above high heat dissipation circuit board, after the first lamination of the substrate 100, the core board 200 and the prepreg 300, the substrate 100 and the core board 200 are fixed by the flowing glue of the prepreg 300 to form a multilayer board. Then, the multilayer board is routed to form a via window area. Then, a first barrier 500 and a second barrier 800 are respectively attached to both sides of the multilayer board. The first barrier 500 is provided with a flowing glue hole 510, and the flowing glue hole 510 communicates with the via window area. The heat dissipation module 400 is embedded in the via window area, so that both ends of the heat dissipation module 400 are respectively in contact with the first barrier 500 and the second barrier 800. The buffer layer 700 and the flowing glue layer 600 are sequentially stacked on the first barrier 500 and subjected to a second lamination process. Under the state of high temperature and high pressure, the flowing glue layer 600 melts into a fluid state and passes through the flowing glue hole 510 into the via window area, so that the gap between the heat dissipation module 400 and the multilayer board is filled with the flowing glue layer 600. And because the first barrier 500 and the second barrier 800 are respectively attached to both sides of the multilayer board, the flowing glue layer 600 cannot overflow onto the copper foil on the surface of the multilayer board, thereby avoiding the need to spend a lot of time cleaning the overflowing glue on the copper foil surface in the subsequent process. In this way, the production efficiency is improved, and at the same time, the short circuit problem caused by incomplete removal of the copper foil surface is avoided, further improving the yield of the product.

[0096] The above embodiments only represent several implementation manners of the present disclosure, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A preparation method of a high heat dissipation circuit board, characterized in that, It includes the following steps: Stack the substrate, core board and prepreg, and then perform the first lamination process to form a multilayer board; Perform routing on the multilayer board to form a via opening area on the multilayer board; Perform the first attachment process on the multilayer board so that the first barrier covers the surface of the multilayer board; Perform hole opening on the first barrier so that the first barrier forms a glue flow hole, and the glue flow hole communicates with the via opening area; Place the heat dissipation module in the via opening area; Perform the second attachment process on the multilayer board so that the second barrier covers the side of the multilayer board away from the first barrier; Perform the second lamination process on the buffer layer, glue flow layer and the multilayer board so that the glue flow layer melts and enters the via opening area from the glue flow hole to fix the heat dissipation module to the multilayer board; Perform separation on the multilayer board so that the first barrier and the second barrier are separated from the surface of the multilayer board.

2. The preparation method of the high heat dissipation circuit board according to claim 1, characterized in that, Performing the second lamination on the buffer layer, glue flow layer and multilayer board specifically includes the following steps: Stack the buffer layer and the glue flow layer on the first barrier, and the glue flow layer is located between the buffer layer and the first barrier; Perform the second lamination on the buffer layer, glue flow layer and multilayer board under high temperature and high pressure conditions so that the glue flow layer melts and enters the via opening area from the glue flow hole.

3. The preparation method of the high heat dissipation circuit board according to claim 1, wherein, Before placing the heat dissipation module in the via opening area, it further includes the following steps: Apply a film to the heat dissipation module so that a partial area of the heat dissipation module adjacent to the glue flow hole is covered with a barrier film.

4. The preparation method of the high heat dissipation circuit board according to claim 3, characterized in that, After applying a film to the heat dissipation module, it further includes the following steps: Cut the heat dissipation module to make the surface of the heat dissipation module rough.

5. The preparation method of the high heat dissipation circuit board according to claim 1, characterized in that, The first barrier is a polyimide film; and / or, The second barrier is a polyimide film.

6. The preparation method of the high heat dissipation circuit board according to claim 5, characterized in that, Performing hole opening on the first barrier specifically includes the following steps: Use a laser to ablate the first barrier so that the first barrier forms the glue flow hole.

7. The preparation method of the high heat dissipation circuit board according to claim 1, wherein Before performing routing on the multilayer board, it further includes the following steps: Drill holes in the multilayer board to form positioning holes.

8. The preparation method of the high heat dissipation circuit board according to claim 1, characterized in that After performing separation on the multilayer board, it further includes the following steps: Perform grinding on the multilayer board.

9. The preparation method of the high heat dissipation circuit board according to claim 1, characterized in that Performing separation on the multilayer board specifically includes the following steps: Perform a tearing operation on the first barrier, glue flow layer and buffer layer to separate the first barrier from the multilayer board; Perform a tearing operation on the second barrier to separate the second barrier from the multilayer board.

10. A high heat dissipation circuit board with an embedded heat dissipation component, characterized in that, Prepared by using the preparation method of the highly heat-dissipating circuit board according to any one of claims 1 to 9, the highly heat-dissipating circuit board includes at least one core board, two substrate boards, prepregs and a heat-dissipating module. The core board is located between the two substrate boards, and the prepregs are clamped between the core board and the substrate boards to fix the substrate boards and the core board. The substrate boards, the core board and the prepregs jointly form a via opening area, the heat-dissipating module is located in the via opening area, and the heat-dissipating module is fixed to the substrate boards, the core board and the prepregs respectively through an adhesive layer.

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