TWM583663U - Printed circuit board and electronic apparatus - Google Patents

Abstract

The present disclosure provides a printed circuit board and an electronic apparatus. The printed circuit board includes a core component, a heat dissipation dervice, and conductive bonding layer. The core component may include a first core plate and a second core plate arranged in sequence and stacked together, wherein the second core plate includes a metal layer arrangd at a side thereof adjacent to the first core plate. The first core plate may include a through slot passing through the first core board. At least a part of the heat dissipation device may be contained in the through slot. A conductive adhesive layer may be arranged between the metal layer of the second core plate and the heat dissipation device for electrically connectingthe heat dissipation device to the metal layer. The present disclosure directly connects the heat dissipation device to the metal layer via the conductive adhesive layer, so as to strengthen the grounding performance of electronic components on the printed circuit board, and help the metal layer to dissipate heat, thereby improving the heat-dissipation performance of the printed circuit board.

Description

Printed circuit board and electronic device

This creation relates to the technical field of integrated circuits, and particularly relates to a printed circuit board and an electronic device.

Printed Circuit Board (PCB) is an important electronic component and one of the important components of the electronics industry. Almost every kind of electronic equipment, from electronic watches, calculators, to computers, communication electronic equipment, military weapon systems, as long as there are integrated circuits and other electronic components, in order to achieve electrical interconnection between them, all use printing Circuit board. Therefore, the printed circuit board plays an increasingly important role in the field of circuit technology. As the volume of electronic equipment continues to shrink, the functions of electronic devices are gradually perfected. If more electronic components are installed in a smaller space, the heating of the circuit board will inevitably increase, so the heat dissipation of the circuit board is solved. The problem becomes particularly urgent.

The main technical problem solved by this creation is to provide a printed circuit board and an electronic device to solve the problem of heat dissipation of the circuit board caused by the reduction of the size of the electronic device.

In order to solve the above technical problems, a technical solution used in this creation is to provide a printed circuit board including: a core board component, including a sequential stacking A first core plate and a second core plate, a metal layer is disposed on a side of the second core plate near the first core plate, and the first core plate is provided with a through slot penetrating through the first core plate; At least partially accommodated in the through groove; and a conductive adhesive layer is disposed between the metal layer of the second core board and the heat dissipation device for electrically connecting the heat dissipation device to the metal layer.

In order to solve the above technical problem, another technical solution adopted in this creation is to provide an electronic device including: a printed circuit board including a core board component including a first core board and a second core board which are sequentially stacked, and the second A metal layer is disposed on a side of the core board that is close to the first core board. The first core board is provided with a through slot penetrating through the first core board, and the second core board is provided with a through hole that penetrates the second core board. A mounting groove; a first heat dissipation device accommodated in the through groove; a conductive adhesive layer disposed between the metal layer of the second core board and the first heat dissipation device for connecting the first heat dissipation device to the A metal layer is electrically connected; and a heat generating device is installed in the mounting groove, and a maximum cross-sectional area of the heat generating device is smaller than an area of a bottom surface of the first heat dissipation device constituting the mounting groove.

In order to solve the above technical problems, another technical solution adopted in this creation is: providing a first core board, a second core board, a heat sink and a conductive bonding material, a metal layer is provided on one side of the second core board; A core plate is grooved to form a first through groove penetrating the first core plate; the heat sink is placed in the first through groove; and the first core plate and the second core plate are pressed together To form the printed circuit board, the heat sink is connected to the metal layer through the conductive adhesive material.

The beneficial effects of the above embodiment are: by providing a through groove on the core board element, and placing the heat sink in the through groove on the core board element, and then using The conductive adhesive layer connects and conducts the heat dissipation device with the metal layer on the second core board, while enhancing the grounding performance of the electronic components provided on the printed circuit board, it can also help the electronic components to dissipate heat, thereby improving printing. Thermal performance of the circuit board.

100‧‧‧printed circuit board

10‧‧‧ core board components

20‧‧‧Cooling device

30‧‧‧ conductive adhesive layer

12‧‧‧ the first core board

14‧‧‧Second core board

120‧‧‧ core board medium

140‧‧‧ core board medium

142‧‧‧ ground plane

144‧‧‧First Signal Layer

16‧‧‧through slot

18‧‧‧ the first connection layer

19‧‧‧Second connection layer

40‧‧‧Mounting slot

50‧‧‧via

52‧‧‧ conductive layer

300‧‧‧ electronic device

200‧‧‧heating device

20a‧‧‧The first heat dissipation device

210‧‧‧Electronics

220‧‧‧Second heat dissipation device

80‧‧‧ conductive welding material layer

60‧‧‧Metal cover

FIG. 1 is a schematic cross-sectional view of the overall structure of a printed circuit board in an embodiment of the present invention.

FIG. 2 is a schematic diagram of the three-dimensional structure of the first heat dissipation device according to another embodiment of the present invention.

FIG. 3 is a three-dimensional structure diagram of an electronic device according to another embodiment of the present invention.

FIG. 4 is a schematic diagram of the three-dimensional structure of the electronic device according to another embodiment of the present invention.

FIG. 5 is a schematic diagram of the three-dimensional structure of the electronic device according to another embodiment of the present invention.

FIG. 6 is a schematic diagram of a three-dimensional structure of an electronic device according to another embodiment of the present invention.

FIG. 7 is a schematic diagram of the three-dimensional structure of the electronic device according to another embodiment of the present invention.

FIG. 8 is a flowchart of a method for manufacturing a printed circuit board according to another embodiment of the present invention.

FIG. 9 is a flowchart of a method for manufacturing a printed circuit board according to another embodiment of the present invention.

Figure 10 shows the production of a printed circuit board according to another embodiment of the present invention. Method flow chart.

FIG. 11 is a manufacturing process flow chart of a printed circuit board according to another embodiment of the present invention.

FIG. 12 is a flowchart of a manufacturing process of a printed circuit board according to another embodiment of the present invention.

FIG. 13 is a manufacturing process flow chart of a printed circuit board according to another embodiment of the present invention.

FIG. 14 is a flowchart of a manufacturing process of a printed circuit board according to another embodiment of the present invention.

FIG. 15 is a manufacturing process flow chart of a printed circuit board according to another embodiment of the present invention.

The technical solution in the embodiment of the present invention will be clearly and completely described below. Obviously, the described embodiment is only a part of the embodiment of the present invention, but not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative labor belong to the protection scope of the present invention.

The terms "first" and "second" in this creation are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this creation, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically and specifically defined. All directional indicators (such as up, down, left, right, front, back, etc.) in this creative embodiment are only used to explain in a specific posture (as shown in the figure) (Shown) The relative positional relationship, movement situation, etc. of each element under the direction, if the specific posture changes, the directionality indication will change accordingly. Furthermore, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device containing a series of steps or elements is not limited to the listed steps or elements, but optionally also includes steps or elements not listed, or optionally also Include other steps or elements inherent to these processes, methods, products or equipment.

In the description of this creation, it should be noted that the terms "installation", "connected", "connected", "set on" should be understood in a broad sense, unless explicitly stated and limited otherwise, for example, it could be A fixed connection can also be a detachable connection or an integral connection; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this creation can be understood according to specific situations.

In the description of this creation, unless otherwise stated, "multiple" means two or more. If the term "process" appears in this specification, it means not only an independent process, but when it cannot be clearly distinguished from other processes, it is also included in the term as long as the intended function of the process can be achieved. In addition, the numerical range indicated by "-" in this specification means the range which includes the numerical value described before and after "-" as a minimum value and a maximum value, respectively. In the drawings, similar or identical components are denoted by the same reference numerals.

In addition, in the description of this creation, electronic devices may include, for example, smartphones, tablet personal computers, mobile phones, video phones, e-book readers, desktop computers, laptops, netbook computers, workstations, servers, personal computers, etc. One of digital assistants, portable multimedia players, players, medical equipment, cameras, and wearable devices. Wearable devices can include accessories (e.g., watches, rings, bracelets, anklets, glasses, contact lenses, or head-mounted devices), clothing-integrated (e.g., electronic clothing), body-attached (e.g., skin pads or tattoos), or implantable Type (eg implantable circuit). In some embodiments, home appliances may include, for example, digital versatile disc players, audio, refrigerators, air conditioners, cleaners, ovens, microwave ovens, washing machines, air filters, set-top boxes, home automation consoles, security consoles , TV box, game console, electronic dictionary, electronic key, camera and electronic panel, etc.

Electronic devices can also include various medical devices (such as various portable medical measurement devices (blood glucose meters, heart rate measurement devices, blood pressure measurement devices, and temperature measurement devices), magnetic resonance angiography, magnetic resonance imaging devices, computer tomography devices, photography Devices and ultrasonic devices), navigation systems, global navigation satellite systems), event data recorders, flight data recorders, vehicle infotainment devices, electronic devices for ships (e.g. navigation devices and gyrocompasses for ships), aviation Electronics, security devices, vehicle head units, industrial or home robots, ATMs for financial companies, point-of-sale and IoT (e.g. light bulbs, various sensors, electricity or gas meters, sprinkler devices, fire alarms) Device, thermostat, telephone pole, toaster, sports device, hot water tank, heater, and boiler). According to various embodiments of the present disclosure, the electronic device may include a piece of furniture or a building / structure or a vehicle, an electronic board, an electronic signature receiving device, a projector, or various measuring devices such as a water service, electrical energy, gas, or radio wave measuring device ). In various embodiments of the present invention, the electronic device may be flexible, or the electronic device may be two or more of the various devices Combinations. The electronic device according to the embodiment of the present invention is not limited to the above-mentioned devices.

Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they independent or alternative embodiments that are mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

Please refer to FIG. 1. FIG. 1 is a schematic cross-sectional view of the overall structure of a printed circuit board in an embodiment of the present invention.

As shown in FIG. 1, in this embodiment, the printed circuit board 100 may generally include: a core board element 10, a heat sink 20 and a conductive adhesive layer 30 embedded in the core board assembly 10, and the heat sink 20 The conductive adhesive layer 30 is connected to the core board element 10.

Wherein, the core plate element 10 may include a first core plate 12 and a second core plate 14 that are sequentially stacked.

As shown in FIG. 1, in this embodiment, the first core plate 12 may include a core plate medium 120 and a metal layer on at least one side of the core plate medium 120.

Likewise, the second core plate 14 may include a core plate medium 140 and a metal layer on at least one side of the core plate medium 140.

The selection of the materials of the core board media 120 and 140 can be selected according to the functional design of each layer of the core board. It is also possible that they are all materials suitable for wireless circuits with a small loss factor (DF), such as ceramic-based high-frequency materials or polytetrafluoroethylene. It can also be a material with a large loss factor suitable for conventional circuits, such as FR-4 (including epoxy resin).

In this embodiment, in addition to the core board media 120 and 140 being made of a material that allows wireless signals of a certain frequency to pass through, the material may also be a thermosetting material, and the core board media 120 and 140 are cured by heat treatment in advance, so their shapes Fixed, during the subsequent heating process, the core plate media 120 and 140 will not deform again. The core plate medium may be a thermoplastic material that softens after heating.

Among them, thermosetting material refers to: the material can be softened and flowed when heated for the first time, heated to a certain temperature, a chemical reaction is generated, and the cross-linking is solidified and hardened; this change is irreversible. Can no longer soften and flow.

Common thermosetting materials include, but are not limited to, allyl resin, epoxy resin, thermosetting polyurethane, silicone or polysiloxane, and the like. These resins may be formed from the reaction products of a polymerizable composition that includes at least one oligomeric urethane (meth) acrylate. Generally, the oligomeric urethane (meth) acrylate is a poly (meth) acrylate. The term "(meth) acrylate" is used to refer to acrylic and methacrylic esters, and in contrast to "poly (meth) acrylate", which is commonly referred to as (meth) acrylate polymer, "multi ( “Meth) acrylate” refers to a molecule that includes more than one (meth) acrylate group. Most commonly, poly (meth) acrylates are di (meth) acrylates, but tris (meth) acrylates, tetra (meth) acrylates, etc. can also be considered.

Further, a metal layer is disposed on a side of the first core plate 12 adjacent to the second core plate 14.

In this embodiment, the metal layers on the first core plate 12 and the second core plate 14 may both be copper layers. Among them, copper has good electrical conductivity, The most commonly used wiring material for the printed circuit board 100. By patterning each of the first core board 12 and the second core board 14, the required circuit pattern can be obtained, and the metal layer can be divided into a signal layer and a ground layer according to the functional design; The pattern of the ground layer is complicated. Generally, the signal layer is a layer where a plurality of metal lines for forming an electrical connection between electronic devices are located; the ground layer is for connecting to the ground, and is usually a layer of a large-area continuous metal region.

Optionally, the metal layer on the second core board 14 connected to the heat sink 20 through the conductive adhesive layer 30 is the ground layer 142, that is, the indirect electrical connection is achieved between the heat sink 20 and the ground layer 142 on the second core board 14. In this way, the ground layer 142 can be electrically connected directly to the heat sink 20 through the sandwich structure of the sandwich, thereby directly grounding, shortening the grounding path, and thereby improving the grounding effect of the electronic device to be grounded on the printed circuit board 100. And ground stability.

Optionally, referring to FIG. 1, a metal layer is disposed on two opposite sides of the core plate medium 140 of the second core plate 14. The metal layer on the second core board 14 on the side close to the first core board 12 is the ground layer 142, and the metal layer on the other side facing away from the first core board 12 is the first signal layer 144.

The number of the first core plates 12 may be multiple, and the plurality of first core plates 12 may be sequentially stacked. For example, in the illustrated embodiment, the number of the first core plates 12 is two. Of course, in other embodiments, the number of the second core plates 14 may be multiple.

In one embodiment, the core plate element 14 may further include at least one third core plate, and at least one third core plate is stacked on a side of the second core plate 14 facing away from the first core plate 12. Each third core plate may include a core plate medium and A metal layer on at least one side of the core plate dielectric.

In this embodiment, when the number of the third core plates is multiple, one of the third core plates having the largest distance from the second core plate 14 among all the third core plates is away from the second core plate 14 by one. The metal layer on the side is the second signal layer (ie, the outer metal layer of the outermost third core board is the second signal layer).

In the embodiment shown in FIG. 1, the core board assembly 10 includes two layers of the first core board 12 and one layer of the second core board 14, and the order in which the first core board 12 and the second core board 14 are stacked in sequence is the first A core plate 12, a first core plate 12, and a second core plate 14 to form a sandwich-shaped laminated structure.

Further referring to FIG. 1, in this embodiment, the core board assembly 10 may be provided with a through slot 16 for receiving the heat sink 20 and the thermally conductive adhesive layer 30. The through groove 16 penetrates the first core plate 12 along the thickness direction of the first core plate 12 but does not extend to any part of the second core plate 14, that is, the through groove 16 penetrates the first core plate 12 and ends at第二 芯板 14。 The second core plate 14.

In this embodiment, a plurality of first core plates 12 are provided with through grooves (shown in FIG. 8). When the first core plate 12 and the second core plate 14 are sequentially stacked, the first core plate 12 is All the through grooves are aligned and cut off at a metal layer in contact with the second core plate 14 to form the through grooves 16 for receiving the heat sink 20, and the heat sink 20 is at least partially received in the through grooves 16.

As further shown in FIG. 1, in this embodiment, the printed circuit board 100 may further include a first connection layer 18. The first connection layer 18 is disposed between the first core plate 12 and the second core plate 14, and is disposed around the conductive adhesive layer 30 to bond the first core plate 12 and the second core plate 14. In addition, when a plurality of first core plates 12 and a plurality of second core plates 14 are provided, two adjacent first cores The first connection layer 18 may also be provided between the boards 12 and between two adjacent second core boards 14 so as to adhere the plurality of core boards 12 and 14 of the core board component 10 to each other.

In this embodiment, the first connection layer 18 may be an adhesive material, and specifically may be a thermosetting material. The difference between the first connection layer 18 and the core plate media 120 and 140 is that the first connection layer 18 is a thermosetting material that has not been heat-treated. Therefore, when the first connection layer 18 is heated, the first connection layer 18 can be melted, and then the two adjacent first core plates 12, the two adjacent second core plates 14, and the first core plates 12 adjacent to each other can be melted. It is bonded to the second core plate 14.

In other embodiments, the first connection layer 18 may also be made of a thermoplastic material. Among them, thermoplastic materials refer to: Thermoplastic plastics are plastics that have the characteristics of softening by heating and cooling and hardening. It softens to flow when heated, and hardens when cooled. This process is reversible and can be repeated. Common thermoplastic materials include, but are not limited to, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyoxymethylene, polycarbonate, polyamines, acrylic plastics, other polyolefins and their copolymers, polyfluorene, polybenzene Ether, chlorinated polyether, etc. Resin molecular chains in thermoplastics are linear or branched. There is no chemical bond between the molecular chains. They soften and flow when heated, and the process of cooling and hardening is a physical change.

In one example, the thermoplastic material may include: polyketone, polyaramide, polyimide, polyetherimide, polyimide, polyphenylenesulfide, polyphenylenesulfonium, fluoropolymer, Polybenzimidazole, their derivatives, or combinations thereof.

In another example, the thermoplastic material may include a polymer, such as a polyketone, a thermoplastic polyimide, a polyetherimide, a polyphenylene sulfide, a polyether, a polyfluorene, a polyimide, an imine, Their derivatives, or combinations thereof.

In yet another example, the thermoplastic material may further include polyketones, Such as polyetheretherketone, polyetherketone, polyetherketoneketone, polyetherketoneetherketone, their derivatives, or combinations thereof. An exemplary thermoplastic fluoropolymer includes fluorinated ethylene propylene, polytetrafluoroethylene, polyvinylidene fluoride, perfluoroalkoxy, tetrafluoroethylene, hexafluoropropylene, and a trimerization of vinylidene fluoride. Polymer, polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, or any combination thereof.

In this embodiment, the maximum cross-sectional area of the through groove 16 is larger than the maximum cross-sectional area of the heat sink 20, so that a gap can be formed between the outer wall of the heat sink 20 and the side wall of the first core plate 12 surrounding the through groove 16. 17. The maximum cross-sectional area of the through groove 16 refers to the maximum area of the projection of the through groove 16 in a direction perpendicular to the stacking direction of the first core plate 12 and the second core plate 14. The maximum cross-sectional area of the heat dissipation device 20 refers to a maximum area of a cross section of the heat dissipation device 20 along a direction perpendicular to the lamination direction of the first core plate 12 and the second core plate 14.

The shape of the heat dissipation device 20 matches the shape of the through groove 16. The heat sink 20 may be at least partially accommodated in the through groove 16. That is, the heat dissipating device 20 may be partially accommodated in the through groove 16, or may be completely accommodated in the through groove 16 for dissipating heat from the heat generating device provided on the printed circuit board 100.

For example, the length of the heat sink 20 in the laminating direction of the first core plate 12 and the second core plate 14 is greater than the depth of the through groove 16. At this time, on the side of the first core plate 12 remote from the second core plate 14, the heat sink 20 protrudes from the outer surface of the first core plate 12.

In this embodiment, in a direction along which the first core plate 12 and the second core plate 14 are stacked, the length of the heat sink 20 is equal to the depth of the through groove 16, so that the heat sink 20 can be completely filled in the through groove 16. To reduce printed circuits The volume of the plate 100.

Specifically, the heat dissipation device 20 is a device having a function of conducting and conducting heat, which may be a metal block, which is wholly or partially embedded in the through slot 16, and electrically connects the ground layer 142 and the heat dissipation device 20 through the conductive adhesive layer 30. The connection can improve the grounding performance of the electronic components on the printed circuit board 100 and can dissipate heat for the electronic components.

In one embodiment, the metal block may be made of pure metal. The metal materials used include but are not limited to copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, nickel, nickel alloy, gold, gold alloy, silver , Silver alloy, platinum group, platinum group alloy, chromium, chromium alloy, magnesium, magnesium alloy, tungsten, tungsten alloy, molybdenum, molybdenum alloy, lead, lead alloy, tin, tin alloy, indium, indium alloy, zinc or zinc alloy Wait.

In another embodiment, the material of the metal block may also be composed of a metal-based block and a conductive graphite sheet. Since the thermal resistance of the conductive graphite sheet is smaller than that of ordinary metals and alloys, the conductive graphite sheet can be embedded in the metal to make the heat conduction faster. The material of the heat dissipation device 20 is not limited in this creation.

The shape of the heat dissipation device 20 may be a regular shape such as a cube, a cylinder, and a cube, or may be an irregular shape. The present invention does not limit the structure of the heat dissipation device 20.

Because of the close relationship between the temperature of the object and the surface area of the object during heat dissipation, the larger the surface area of the object, the faster the heat is lost, and the faster the temperature of the object decreases. Referring to FIG. 2, in order to further accelerate heat dissipation, a heat dissipation fin 21 connected to the heat dissipation device 20 may be further provided. The heat dissipation fin 21 may include a base portion 211 and a plurality of fin portions 212. The base portion 211 of the heat dissipation fin 21 is connected to the heat dissipation device 20, and the plurality of fin portions 212 are disposed at intervals. The heat dissipating fin 21 is on the side of the discrete heat device 20. Therefore, the base portion 211 can transfer the heat on the heat sink 20 to the fin portion 212. In addition, since two adjacent fin portions 212 are spaced from each other and have a gap, the gap can form an airflow channel, so the contact area between the heat dissipation fin 21 and the air can be increased, thereby speeding up heat dissipation.

In order to further accelerate the heat dissipation speed, a heat pipe may be further provided on the heat dissipation fin 21. For example, each fin portion 212 may be provided with at least one perforation, and each perforation may be provided with a heat pipe. The arrangement of the heat pipe can further increase the contact area between the heat sink 20 and the air, and speed up the heat dissipation. Optionally, in order to improve the heat dissipation effect of the heat dissipation device 20, a thermally conductive adhesive may be coated between the heat pipe and the wall of the perforated hole. Since the heat conductivity of the heat pipe is much higher than that of pure metals such as copper and aluminum, and the heat transfer is non-directional and has a certain length, it can transfer heat to a long distance, so it has a significant effect on improving heat dissipation performance.

Of course, this implementation can also use other implementations that can increase the heat dissipation area of the heat dissipation device 20 to speed up the heat dissipation. These implementations are similar to the structure and principle of this creation and belong to the protection scope of this creation.

Continuing to refer to FIG. 1, in this embodiment, the conductive adhesive layer 30 is disposed between the ground layer 142 of the second core board 14 and the heat sink 20, and is used to connect the heat sink 20 and the ground layer on the second core board 14. 142 electrical connection.

Wherein, the conductive adhesive layer 30 is an adhesive layer having conductivity and adhesion. The conductive bonding material may be a mixture of a conductive material and a viscous material, wherein the conductive material may be metal or graphite; the viscous material may be epoxy resin.

Therefore, the conductive adhesive layer 30 is provided on the heat sink 20 and the core. When the stacked sandwich structures are formed between the plate elements 10, on the one hand, the heat sink 20 can be indirectly electrically connected to the ground layer 142 on the second core board 14, and the ground layer 142 on the second core board 14 is grounded. . On the other hand, because the conductive adhesive layer 30 has adhesiveness, the heat dissipation device 20 and the ground layer 142 can be tightly bonded together to ensure the contact effect between the heat dissipation device 20 and the ground layer 142 of the second core board 14. In addition, the conductive adhesive sheet 30 also has thermal conductivity, and can transfer the heat generated by the heat-generating device to the heat-dissipating device 20 to accelerate the heat-radiation of the heat-generating device.

Among them, the conductive bonding 30 layer is used to realize the indirect electrical connection between the heat sink 20 and the ground layer 142 on the second core board 14, because the contact area between the conductive bonding layer 30 and the metal layer 142 is larger than the hole and metal layer of conventional drilling and grounding. The contact area of 142 is increased. Therefore, the use of the conductive adhesive layer 30 to increase the contact area can make the grounding stability of the ground layer 142 better.

In one embodiment, for example, the conductive adhesive layer 30 may be a conductive adhesive material. The so-called conductive bonding material may be in the form of a paste or paste having a certain fluidity, or may be a semi-cured form. Among them, the semi-immobilized form is solid at normal temperature, but has a certain fluidity when heated to a certain temperature, and then forms a final cure at a certain temperature.

During production, the conductive material may be bonded to the heat sink 20 or the ground layer 142 of the second core board 14 connected to the heat sink 20 by printing or coating, and then placed in the heat sink 20, and the first When the core plate 12 and the second core plate 14 are pressed together to form a laminated sandwich structure, the heat sink 20 is bonded to the ground layer 142 of the second core plate 14.

The conductive material includes, for example, a resin matrix, conductive particles, and Conductive adhesive composed of dispersing additives, auxiliaries, etc. The resin matrix may be an adhesive system such as epoxy resin, silicone resin, polyimide resin, phenol resin, polyurethane, acrylic resin, and the like. These adhesives, after curing, form the molecular skeleton structure of the conductive adhesive, which provides the guarantee of mechanical properties and adhesion properties, and makes the conductive filler particles form channels. The conductive particles can be powders of gold, silver, copper, aluminum, zinc, iron, nickel, graphite, and some conductive compounds to achieve conductive properties.

In addition, the conductive material may also be a conductive silver paste, a conductive copper paste, or a conductive solder paste. Taking the conductive silver paste as an example, during use, the conductive silver paste can be coated on the heat sink 20 and the ground layer 142 connected to the heat sink 20, and the conductive silver paste is coated before the conductive silver paste is cured. The regions are bonded to each other, and the conductive silver paste can be cured to form a conductive bonding layer 30 through a subsequent curing process, so that the heat sink 20 and the ground layer 142 of the second core board 14 can be bonded.

In another embodiment, the conductive adhesive layer 30 may also be a semi-cured adhesive sheet. During production, the semi-cured adhesive sheet is bonded to the heat sink 20 or the ground layer 142 on the second core board, and then the side of the heat sink 20 to which the semi-cured adhesive sheet is attached is placed on the core board assembly 10. In the through groove 16, the heat sink 20 is bonded to the metal layer 142 of the second core plate 14 when the first core plate 12 and the second core plate 14 are pressed together to form a sandwich structure. It can be understood that all the ways of using the conductive adhesive layer 30 to realize the indirect electrical connection between the heat dissipation device 20 and the ground layer 142 on the second core board 14 are within the protection scope of this creation.

In one embodiment, the conductive adhesive layer 30 may be a conductive foam. The conductive foam can be provided with a conductive double-sided adhesive on opposite sides thereof, so that the conductive foam can be adhered to the heat dissipation device 20 and the ground layer 142 through the double-sided adhesive on the opposite two sides, thereby realizing the heat dissipation device. 20 and second core plate 14 The bonding and electrical connection of the upper ground layer 142. Among them, the conductive foam has the characteristics of good electrical conductivity and large elasticity, which can effectively fill the tiny gap between the heat sink 20 and the ground layer 142, and make sufficient contact between the heat sink 20 and the ground layer 142, so that it can effectively Overcome the problem of insufficient grounding caused by insufficient contact between the heat sink 20 and the ground layer 142 during installation.

Since the epoxy resin can be cured at room temperature or lower than 150 ° C, and has rich formula design performance, in another embodiment, the adhesive sheet can also be obtained by adding metal silver to the epoxy resin. A solid bonding sheet to achieve bonding and electrical connection between the heat sink 20 and the ground layer 142 on the second core board 14.

In addition, in order to make the outer wall of the heat sink 20 and the inner wall of the first core board 12 adhere to each other, a gap between the outer wall of the heat sink 20 and the inner wall of the through slot 16 on the first core board 12 may be included. A second connection layer 19 is disposed in the gap 17. The second connection layer 19 may also be made of an untreated thermosetting material or a thermoplastic material. Therefore, when the core board element 10 is heated, the second connection layer 19 can be uniformly filled in the gap 17 after being heated and melted, which can not only make the heat sink 20 and the first core board 12 closely adhere to each other to reduce the possibility of falling off. Sex.

The material of the first connection layer 18 and the material of the second connection layer 19 may be the same or different. In this embodiment, the material of the first connection layer 18 is the same as that of the second connection layer 19, and the first connection layer 18 and the second connection layer 19 are integrally formed.

Specifically, when a plurality of first core plates 12 and a plurality of second core plates 14 are provided, the two first core plates 12 adjacent to each other and the two second core plates 14 adjacent to each other are utilized by the first connection layer 18. Stick to each other. When adding layered sandwich structures When hot, the first connection layer 18 melts and flows into the gap 17 between the outer side wall of the heat sink 20 and the inner side wall of the first core plate 12 surrounding the through slot 16. After cooling, the housing is formed in A second connection layer 19 at a gap 17 between the inner wall of the through groove 16 and the outer wall of the heat sink 20 and the first core plate 12 is enclosed. By integrally molding the first connection layer 18 and the second connection layer 19, the production process can be simplified and the production efficiency can be improved.

Because the surface of the heat dissipation device 20 has roughness, the heat dissipation device 20 can be smoothly put into the through groove 16 only when the width of the gap 17 is greater than 0.05 mm. At the same time, if the gap 17 is too large, more second connection layers 19 need to be filled in the gap 17, causing waste. Therefore, in order to solve the above problem, in the present creative embodiment, the size of the gap 17 is set to 0.05 mm-0.2 mm. For example, the size of the gap 17 may be 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, or 0.2 mm. On the one hand, the heat dissipation device 20 can be easily placed in the through groove 16; on the other hand, while ensuring the bonding strength, less bonding material is used and the cost is lower.

In this embodiment, the first connection layer 18 and the second connection layer 19 are both made of a prepreg.

Among them, in order to ensure that the prepreg in the first connection layer 18 between the first core plate 12 and the second core plate 14 can be filled after the prepreg is melted, it is usually provided between the first core plate 12 and the second core plate 14 The interval is larger than the size of the gap 17 between the outer wall of the heat sink 20 and the inner wall of the through groove 16, and the size of the gap 17 is usually set to 0.08 mm-0.15 mm.

Further referring to FIG. 1, a cross-sectional area of the conductive adhesive layer 30 may be less than or equal to a surface of a surface of the heat dissipation device 20 that is in contact with the conductive adhesive layer 30. To prevent the conductive adhesive layer 30 from melting and flowing into the gap 17, causing a short circuit between the heat sink 20 and the metal layer on the first core plate 12. The cross-sectional area of the conductive adhesive layer 30 refers to an area in a direction parallel to a surface of the heat dissipation device 20 that is in contact with the conductive adhesive layer 30.

Further, as shown in FIG. 3 to FIG. 7, a groove 222 may be further formed on an end surface of the heat sink 20 that is in contact with the ground layer 142. Therefore, when the first core plate 12 and the second core plate 14 are pressed together, due to the limitation of the groove 222, the conductive adhesive layer 30 can be filled in the groove 222 after melting, to prevent the conductive adhesive layer 30 from overflowing and It flows between the outer wall of the heat sink 20 and the inner wall of the through groove 16, so that the metal layer on the first core plate 12 can be prevented from being directly connected to the heat sink 20 and short-circuited.

Further, in a direction in which the first core plate 12 and the second core plate 14 are stacked, the groove 222 is formed by a surface of the heat sink 20 that is in contact with the ground layer 142 in a direction away from the ground layer 142.

As shown in FIG. 3, in this embodiment, a cross section of the groove 222 is rectangular in a direction perpendicular to the first core plate 12. The width of the opening of the groove 222 is smaller than the width of the cross section of the heat sink 20.

Specifically, in a direction perpendicular to the first core plate 12, a distance between a sidewall of the groove 222 and an outer sidewall of the heat sink 20 is greater than or equal to a preset distance, so that the conductive adhesive layer 30 and the heat sink 20 are connected to each other. The contact area of the ground layer 142 is the largest, which improves the connection stability.

The preset distance is determined by the processing accuracy and the strength of the side wall of the groove 222, and can be flexibly selected according to needs, and is not specifically limited in this creation.

Of course, the length of the opening of the groove 222 can also be equal to the heat dissipation device. The width of the cross section of the device 20 is, for example, the embodiment shown in FIGS. 5 and 6. By setting the length of the opening equal to the width of the cross section of the heat sink 20, the contact area of the conductive adhesive layer 30 and the ground layer 142 can be further increased, thereby further improving the connection stability.

Specifically, at a position close to the outer wall of the heat sink 20, an angle is formed between the side wall of the groove 222 and the outer wall of the heat sink 20, and the angle is less than 90 degrees. That is, in a direction perpendicular to the first core plate 12, the cross section of the groove 222 may be a circular arc shape or an inverted trapezoid. For example, in the embodiment shown in FIG. 5, the cross section of the groove 222 is trapezoidal. In the embodiment shown in FIG. 6, the cross section of the groove 222 is arc-shaped.

Continuing as shown in FIG. 1, the second core plate 14 is further provided with a mounting groove 40 penetrating through the second core plate 14, and the mounting groove 40 is used to further install a heat generating device (shown in FIG. 7). In this embodiment, the mounting groove 40 is provided corresponding to the position of the heat dissipation device 20, and the mounting groove 40 passes through the conductive adhesive layer 30 and extends to the surface or inside of the heat dissipation device 20, but its depth is less than the height of the printed circuit board 100. When a first signal layer 144 is disposed on a side of the second core board 14 facing away from the first core board 12, the mounting groove 40 can also extend from the first signal layer 144 on the second core board 14 to the heat sink 20. Surface or interior.

The extension of the mounting groove 40 to the inside of the heat sink 20 specifically means that the depth of the mounting groove 40 is greater than the thickness of the second core board 14 and smaller than the thickness of the printed circuit board 100. In addition, the area of the conductive adhesive layer 30 occupied by the mounting groove 40 is smaller than the cross-sectional area of the conductive adhesive layer 30 so that the heat sink 20 can be connected to the ground layer 142 on the second core board 14 through the remaining conductive adhesive layer 30.

In this embodiment, a depth control milling operation can be performed on the second core plate 14 Yi directly mills a mounting groove 40 of a predetermined depth on the second core plate 14. By adopting the controlled depth milling process, the mounting groove 40 with a predetermined depth can be machined on the second core plate 14 and the heat sink 20 at one time; its forming steps are small, only one processing benchmark needs to be selected, and the processing accuracy of the product can be improved .

As shown in FIG. 1, the printed circuit board 100 may further include a via 50. In this embodiment, the via 50 penetrates the second core board 14 and extends from the first signal layer 144 of the second core board 14 to the inside of the heat sink 20 through the conductive adhesive layer 30. In addition, a conductive layer 52 is also disposed in the via hole 50 to electrically connect the first signal layer 144 of the second core board 14 and the ground layer 142 of the second core board 14.

When the core board assembly 10 further includes a third core board, the via 50 extends from the second signal layer of the third core board through the second core board 14 to the inside of the heat sink 20. In addition, a conductive layer 52 is also disposed in the via hole 50 to electrically connect the second signal layer of the third core board and the ground layer 142 of the second core board 14.

Specifically, the conductive layer 52 in the via 50 may extend from the first signal layer 144 of the second core board 14 or the second signal layer of the third core board to the heat sink 20, so the second core board may be The first signal layer 144 in the 14 or the second signal layer of the third core board is directly connected to the heat sink 20 to strengthen the grounding performance of the first signal layer 144 or the second signal layer, and further accelerate the The heat is dissipated, thereby improving the heat dissipation performance of the printed circuit board 100.

In another embodiment, the via 50 may also extend from the first signal layer 144 of the second core board 14 or the second signal layer of the third core board to the conductive adhesive layer 30 without passing through the conductive adhesive layer 30. And heat sink 20. In another embodiment, the maximum cross-sectional area of the conductive adhesive layer 30 is smaller than that on the heat sink 20. When the area of the surface in contact with the conductive adhesive layer 30, the via 50 may also extend from the first signal layer 144 of the second core board 14 or the second signal layer of the third core board to the heat sink 20, but it is not penetrated Through the conductive adhesive layer 30. The metal material of the conductive layer 52 may include, but is not limited to, titanium, palladium, zinc, cadmium, gold or brass, bronze, etc .; it may also be a diffusion layer, such as nickel-silicon carbide, nickel-fluorinated graphite, etc .; Composite layer, such as copper-nickel-chromium layer, silver-indium layer, etc. It is not limited in this embodiment.

Further, as shown in FIG. 1, a metal capping layer 60 is further provided on a side of the first core plate 12 remote from the second core plate 14, and the metal capping layer 60 is used to cap the through groove 16 (the first (Shown in Figure 1).

Specifically, a metal capping layer 60 is provided on a side of the first core plate 12 remote from the second core plate 14. The metal cover layer 60 can further seal the heat sink 20 in the through groove 16 to prevent the heat sink 20 from falling. On the other hand, the metal cover layer 60 can further increase the heat dissipation volume of the heat sink 20 and accelerate heat dissipation. At the same time, the metal capping layer 60 can also prevent the second connection layer 19 in the molten state in the gap 17 from overflowing from the gap 17 and reduce subsequent processing.

The metal capping layer 60 may be formed by electroplating or formed by coating a metal material, which is not specifically limited in this creation.

Referring to FIG. 7, the present invention further provides an electronic device 300, which includes a printed circuit board 100 and a heat generating device 200.

The printed circuit board 100 in this embodiment includes a core board element 10, a first heat sink 20 a, and a conductive adhesive layer 30.

The structure of the printed circuit board 100 in this embodiment is similar to that of the printed circuit board 100 in the previous embodiment. In this embodiment, only the description of The printed circuit board 100 in one embodiment has different structures, and the same structures are not described herein again. In addition, the structure of the first heat sink 20a in this embodiment is the same as the structure of the heat sink 20 in the previous embodiment. The detailed structure of the first heat sink 20a is not described in detail here. Please refer to the heat sink in the previous embodiment. 20 structure.

The heating device 200 is installed in the mounting groove 40 of the printed circuit board 100, and the maximum cross-sectional area of the heating device 200 is smaller than the area of the bottom surface of the first heat sink 20a constituting the mounting groove 40. The maximum cross-sectional area of the heating device 200 is the maximum area of a cross section perpendicular to the lamination direction of the first core plate 12 and the second core plate 14.

Wherein, the heat generating device 200 may be a heat generating member or a part of which includes the heat generating member. Examples are electrical parts, application processors, or IC chips. The heat generating device 200 is installed in the mounting groove 40. The heat-generating device 200 is connected to the first heat-dissipating device 20a through a conductive solder material layer 80 (solder paste, tin sheet, or copper paste, etc.). The thermally conductive resin 80 effectively transfers heat from the heat-generating device 200 from the heat-generating device 200 to the first heat-dissipating The device 20a realizes heat dissipation.

In one embodiment, the heat-generating device 200 is a component that generates heat, and the heat-generating device 200 is directly connected to the first heat-dissipating device 20a. In this way, the surface area for heat dissipation is further increased, and the heat dissipation performance of the printed circuit board 100 is improved.

As shown in FIG. 7, in yet another embodiment, the heat generating device 200 includes an electronic device 210 and a second heat dissipation device 220.

Among them, the electronic device 210 may be a packaged or unpackaged (ie, no integrated circuit base, plastic encapsulant, or ceramic case) integrated circuit, a triode, or an IGBT (Insulated Gate Bipolar Transistor). And MOS tube (metal oxide semiconductor, field effect transistor).

The second heat dissipation device 220 is placed in the mounting groove 40, and the second heat dissipation device 220 is located between the first heat dissipation device 20a and the electronic device 210, and is configured to transfer the heat emitted by the electronic device 210 to the second heat dissipation device 220 to The first heat sink 20a is further emitted by the first heat sink 20a. Therefore, by providing the second heat sink 220 between the electronic device 210 and the first heat sink 20a, the heat of the electronic device 210 can be quickly transferred to the first heat sink 20a, and the heat dissipation performance of the printed circuit board 100 is improved. The maximum cross-sectional area of the second heat sink 220 is smaller than the area of the bottom surface of the first heat sink 20a forming the mounting groove 40. Similarly, the maximum cross-sectional area of the second heat sink 220 is the maximum area of a cross section perpendicular to the lamination direction of the first core plate 12 and the second core plate 14.

In this embodiment, the second heat dissipation device 220 may be a metal block. The metal used to make the metal block includes, but is not limited to, copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, nickel, nickel alloy, gold, Gold alloy, silver, silver alloy, platinum group, platinum group alloy, chromium, chromium alloy, magnesium, magnesium alloy, tungsten, tungsten alloy, molybdenum, molybdenum alloy, lead, lead alloy, tin, tin alloy, indium, indium alloy, Zinc or zinc alloy, etc.

In another embodiment, the metal block may be composed of a metal base block and a conductive graphite sheet. Since the thermal resistance of the conductive graphite sheet is smaller than that of ordinary metals and alloys, the conductive graphite sheet can be embedded in the metal to make the heat conduction faster. In this creation, the material of the second heat dissipation device 220 is not limited.

The shape of the second heat dissipation device 220 may be a regular shape such as a cube, a cylinder, or a cube, or an irregular shape. The structure of the second heat sink 220 is not limited.

There may be various methods for connecting the second heat sink 220 and the first heat sink 20a. For example, the second heat sink 220 and the first heat sink 20a may be directly bonded using conductive adhesive; or the first heat sink 20a may be welded by electric welding. The two heat dissipation devices 220 and the first heat dissipation device 20a are connected together by welding; a conductive solder material layer 80 (a solder paste, a tin sheet, or a copper paste, etc.) can also be used to make the second heat dissipation device 220 and the first heat dissipation device 20a. Adhesion, etc. Understandably, the rest can electrically connect the second heat dissipation device 220 to the first heat dissipation device 20a, and the manners in which heat can be conducted are all within the protection scope of the present invention.

In this embodiment, the second heat sink 220 is electrically connected to the first heat sink 20a, the electronic device 210 provided on the second heat sink 220 is electrically connected, and the ground layer 142 is electrically connected to the first heat sink 20a, thereby The electronic device 210 can be grounded, a grounding method using a via hole is avoided, and the grounding performance is stable.

Please refer to FIGS. 8 to 14. FIGS. 8 to 10 are flowcharts of a method for manufacturing a printed circuit board according to another embodiment of the present invention. FIGS. 1 to 15 are diagrams of another embodiment of the present invention. Manufacturing process flow chart of printed circuit board.

Making the printed circuit board 100 includes the following steps.

S10: Provide a first core plate 12, a second core plate 14, a heat sink 20, and a conductive bonding material 30, and a metal layer is provided on a side of the second core plate 14 near the first core plate 12.

Among them, the number of the first core plate 12 and the second core plate 14 is at least For one. The first core plate 12 may include a core plate medium 120 and a metal layer on at least one side of the core plate medium 120. Likewise, the second core plate 14 may include a core plate medium 140 and a metal layer on at least one side of the core plate medium 140.

In this embodiment, a metal layer is disposed on a side of the first core plate 12 adjacent to the second core plate 14.

That is, each second core plate 14 includes a core plate medium 140, and on the opposite sides of the core plate medium 140, only one metal layer may be provided, or metal layers may be provided on both sides, but at least A metal layer is disposed on a side of the two core boards 14 adjacent to the heat sink 20.

In this embodiment, referring to FIG. 1, a metal layer is disposed on two opposite sides of the core plate medium 140 of the second core plate 14. The metal layer on the second core board 14 on the side close to the first core board 12 is the ground layer 142, and the metal layer on the other side facing away from the first core board 12 is the first signal layer 144. Each of the first core plate 12 and the second core plate 14 needs to be subjected to a surface treatment. The surface treatment includes the following steps.

Electroplating is performed on the surfaces of each of the first core plate 12 and the second core plate 14 according to a preset pattern so that a pattern is formed on the surfaces thereof.

Among them, in actual production, tin plating is performed on a part of the surface metal layer of each of the first core plate 12 and the second core plate 14. Areas of the metal layer that have not been electroplated are chemically dissolved. Each of the first core plate 12 and the second core plate 14 after plating is treated with a chemical reagent; wherein, the chemical reagent can react with the non-plated area of the metal layer, but does not react with the plating layer. Therefore, unplated areas on the metal layer can be dissolved. Subsequently, each of the first core plate 12 and the second core plate 14 that have been chemically treated is de-tinned. Processing to obtain the metal layer in the area covered by the plating pattern to form a metal pattern.

After the first core plate 12 and the second core plate 14 having a pattern on the surface are obtained, the following steps can be performed.

S20: Slot processing is performed on the first core plate 12 to form a first through groove 124 penetrating the first core plate 12.

This step specifically includes the following description.

S210: Provide a first connection layer 18 having adhesiveness.

S220: Slot the first core plate 12 and the first connection layer 18 to form a first through groove 124 on the first core plate 12 and form a second through groove 182 on the first connection layer 18.

S230: The processed first connection layer 18 is placed between the first core board 12 and the second core board 14, and the first through groove 124 and the second through groove 182 are aligned. The maximum cross-sectional area of the first through groove 124 and the second through groove 182 should be greater than the maximum cross-sectional area of the heat sink 20 so that the heat sink 20 can be placed in the first through groove 124 and the second through groove 182. .

In this embodiment, the first connection layer 18 may be a thermoplastic material. In one embodiment, the thermoplastic material includes: polyketone, polyaramide, polyimide, polyetherimide, polyimide, polyphenylenesulfide, polyphenylenesulfide, fluoropolymer, Polybenzimidazole, their derivatives, or combinations thereof. In another embodiment, the thermoplastic material includes a polymer, such as a polyketone, a thermoplastic polyimide, a polyetherimide, a polyphenylene sulfide, a polyether, a polyamidine, a polyimide, an imine, Their derivatives, or combinations thereof. In other embodiments, the thermoplastic material includes polyketones, such as polyetheretherketone, polyetherketone, polyetherketoneketone, polyetherketoneetherketoneketone, derivatives thereof, or combinations thereof.

The first connection layer 18 may also be a thermosetting material. In one embodiment, the thermosetting material includes: allyl resin, epoxy resin, thermosetting polyurethane, silicone or polysiloxane. These resins may be formed from the reaction products of a polymerizable composition that includes at least one oligomeric urethane (meth) acrylate. Generally, the oligomeric urethane (meth) acrylate is a poly (meth) acrylate. The term "(meth) acrylate" is used to refer to acrylic and methacrylic esters, and in contrast to "poly (meth) acrylate", which is commonly referred to as (meth) acrylate polymer, "multi ( “Meth) acrylate” refers to a molecule that includes more than one (meth) acrylate group. Most commonly, poly (meth) acrylates are di (meth) acrylates, but tris (meth) acrylates, tetra (meth) acrylates, etc. can also be considered.

In other implementations, when the number of the first core plates 12 is multiple and the number of the second core plates 14 is multiple, performing the slotting process on the first core plates 12 specifically includes the following steps.

S210a: providing a plurality of first connection layers 18 having adhesiveness.

S220a: Slot processing is performed on the plurality of first core plates 12 and the plurality of first connection layers 18 to form first through grooves 124 on the plurality of first core plates 12, and on the plurality of first connection layers 18. A second through groove 182 is formed.

S230a: placing the processed multiple first connection layers 18 between any two adjacent first core boards 12 and between any two adjacent second core boards 14 and one adjacent first core board 12 And a second core plate 14, and align the second through grooves 182 on the plurality of first connection layers 18 with the first through grooves 124 on the plurality of first core plates 12.

Specifically, the first core plate 12 may be sequentially stacked in the vertical direction. And the second core board 14, and the first connection layer 18 is placed between the adjacent first core boards 12 and the plurality of second core boards 14, and between the adjacent first core board 12 and the second core Between the boards 14. For example, when the number of the first core boards 12 is two and the number of the second core boards 14 is two, the order of stacking is: first core board 12, first connection layer 18, first core board 12, The first connection layer 18, the second core plate 12, the first connection layer 18, and the second core plate 14.

S30: Place the heat sink 20 in the first through groove 124.

In one embodiment, the conductive bonding material 30 may be a paste-like or paste-like conductive material. When the conductive adhesive material 30 is a paste-like or paste-shaped conductive material, the step of connecting the heat dissipation device 20 to the metal layer 142 of the second core board 14 through the conductive adhesive material 30 includes: firstly printing or coating the conductive material The heat dissipating device 20 or the metal layer 142 of the second core plate 14 is bonded in a covering manner, and then the heat dissipating device 20 is placed in a slot to realize the connection between the heat dissipating device 20 and the metal layer 142 of the second core plate 14.

The conductive material is, for example, a conductive adhesive composed of a resin matrix, conductive particles, a dispersing additive, an auxiliary agent, and the like. The resin matrix may be an adhesive system such as epoxy resin, silicone resin, polyimide resin, phenol resin, polyurethane, acrylic resin, and the like. These adhesives, after curing, form the molecular skeleton structure of the conductive adhesive, which provides the guarantee of mechanical properties and adhesion properties, and makes the conductive filler particles form channels. The conductive particles can be powders of gold, silver, copper, aluminum, zinc, iron, nickel, graphite, and some conductive compounds to achieve conductive properties. In addition, the liquid conductive material may also be a conductive silver paste, a conductive copper paste, or a conductive solder paste.

In another embodiment, the conductive adhesive layer 30 may also be semi-solid Melted adhesive sheet. When the conductive adhesive layer 30 is a solid adhesive sheet, the step of connecting the heat dissipation device 20 to the ground layer 142 of the second core board 14 through the conductive adhesive layer 30 includes: attaching the conductive adhesive layer 30 to the heat dissipation device 20, and then An end of the heat dissipation device 20 with the conductive adhesive layer 30 attached is first placed in the slot, so that the heat dissipation device 20 is connected to the ground layer 142 of the second core board 14.

In one embodiment, the adhesive sheet may be conductive foam. The conductive foam can be provided with a conductive double-sided adhesive on opposite sides thereof, so that the conductive foam can be adhered to the heat dissipation device and the metal layer through the double-sided adhesive on the opposite two sides, thereby realizing the first heat dissipation device. Adhesion and electrical connection with the metal layer on the second core board. Among them, conductive foam has the characteristics of good electrical conductivity and great elasticity, which can effectively fill the tiny gap between the heat sink and the metal layer, and make sufficient contact between the heat sink and the metal layer, which can effectively overcome the installation process. Insufficient contact between the heat sink and the metal layer causes a problem of poor grounding.

Since the epoxy resin can be cured at room temperature or lower than 150 ° C, and has rich formula design performance, in another embodiment, the adhesive sheet can also be obtained by adding metal silver to the epoxy resin. A solid bonding sheet to achieve the bonding and electrical connection between the first heat sink 20 and the ground layer 142 on the second core board 14. Among them, the method of adding metallic silver to epoxy resin can easily make the above-mentioned adhesive sheet with a thickness between 0.05-0.5 mm and a volume resistance of less than 0.4 mΩ.

After the heat sink 20 is connected to the ground layer 142 of the second core board 14 and placed in the first connection layer 18, the following steps are continued.

S40: Compress the first core plate 12 and the second core plate 14 to The printed circuit board 100 is formed so that the heat sink 20 is connected to the ground layer 142 through the conductive adhesive material 30. This step S40 specifically includes the following description.

The first core plate 12 and the second core plate 14 and the first connection layer 18 are heated, so that the first connection layer 18 melts and flows into and fills between the first core plate 12 and the second core plate 14 and is filled with heat. Between the device 20 and the inner side walls of the first through groove 124 and the second through groove 182, pressure is applied to the first and second core boards 12 and 14 and the first connection layer 18 to form the printed circuit board 100.

Specifically, the first core plate 12 and the second core plate 14 and the first connection layer 18 are hot-pressed. Since the first connection layer 18 is a thermosetting material or a thermoplastic material, the first connection layer 18 softens and flows during heating. Because the cross-sectional area of the first through groove 124 and the second through groove 182 is larger than the maximum cross-sectional area of the heat sink 20, there is a gap 17 between the inner wall of the second through groove 182 and the outer wall of the heat sink 20, and flow The thermosetting material flows into the gap 17 and fills the gap 17 between the inner wall of the second through groove 182 and the outer wall of the heat sink 20. At this time, the heating is stopped, and the flowing thermosetting material cools and hardens and fills the gap 17.

After the printed circuit board 100 is formed, in order to further increase the mounting area on the printed circuit board 100 for mounting the heat generating device 200, a mounting groove 40 is opened in the second core board 14. The mounting groove 40 is provided corresponding to the heat dissipation device 20 and extends to the inside of the heat dissipation device 20. The depth of the mounting groove 20 is smaller than the height of the printed circuit board 100, and the bottom area of the mounting groove 40 is smaller than the cross-sectional area of the conductive adhesive layer 30. When a first signal layer 144 is disposed on a side of the second core board 14 facing away from the first core board 12, the mounting groove 40 can also extend from the first signal layer 144 on the second core board 14 to the heat sink 20. internal.

Wherein, the mounting groove 40 extends to the inner part of the heat sink 20 The body means that the depth of the mounting groove 40 is greater than the thickness of the second core board 14 and smaller than the thickness of the printed circuit board 100. The bottom area of the mounting groove 40 is smaller than the cross-sectional area of the conductive adhesive layer 30, so that the heat sink 20 can be connected to the ground layer 142 on the second core board 14 through the remaining conductive adhesive layer 30.

In this embodiment, the second core plate 14 may be directly milled with a predetermined depth of mounting groove 40 on the second core plate 14 through a depth controlled milling process. By adopting the controlled depth milling process, the mounting groove 40 with a predetermined depth can be processed on the second core plate 14 and the heat sink 20 at one time; the forming steps are few, and only one processing benchmark needs to be selected, and the product processing accuracy is high.

After the mounting groove 40 is formed, a via hole 50 may be further formed in the second core plate 14. The via 50 extends from the first signal layer 144 of the second core board 14 to the inside of the heat sink 20 through the conductive adhesive layer 30.

In other embodiments, when the core board assembly 10 further includes a third core board, the via 50 extends from the second signal layer of the third core board through the second core board 14 to the inside of the heat sink 20.

Specifically, a blind hole or a through hole may be drilled on the second core plate 14 or the third core plate by using a drilling method. The blind hole or the through hole is in contact with the heat dissipation device 20 to enhance the signal layer on the second core plate 14. 144 or the ground effect of the second signal layer of the third core board.

In another embodiment, the via 50 may also extend from the first signal layer 144 of the second core board 14 or the second signal layer of the third core board to the conductive adhesive layer 30 without passing through the conductive adhesive layer 30. And heat sink 20.

In another embodiment, the maximum cross-sectional area of the conductive adhesive layer 30 is smaller than the area of the surface of the heat sink 20 that is in contact with the conductive adhesive layer 30. In this case, the via 50 can also extend from the first signal layer 144 of the second core board 14 or the second signal layer of the third core board to the heat sink 20, but does not pass through the conductive adhesive layer 30.

After the via hole 50 is opened, the via hole 50 and the mounting groove 40 need to be metallized, so that the conductive layer 52 is attached to the inner wall of the via hole 50 and the side wall and the bottom surface of the mounting groove 40. The conductive layer 52 on the inner wall of the via 50 is used to electrically connect the first signal layer 144 of the second core board 14 and the ground layer 142 of the second core board 14.

In this embodiment, the mounting groove 40 and the via hole 50 may be metalized by electroplating. Specifically, in a salt solution containing the metal to be plated, the metal of the mounting tank 40 and the via 50 may be used as a cathode, and the cations to be metal plated in the plating solution may be caused to pass through A metal surface is deposited, thereby forming a conductive layer 52. Commonly used metals for electroplating include, but are not limited to, titanium, palladium, zinc, cadmium, gold or brass, bronze, and the like. Of course, in other embodiments, the metallization treatment of the mounting groove 40 and the via 50 can also be implemented by, for example, coating.

Due to the electroplating, the conductive layer 52 in the mounting groove 40 not only electrically connects the heat sink 20 and the ground layer 142, but also electrically connects the ground layer 142 and the first signal layer 144. Currently, a machining method is often used to remove the conductive layer 52 between the first signal layer 144 and the ground layer 142 of the second core board 14. The machining accuracy of traditional machining is ± 4mil (1mil = 0.0254mm), which is 0.1016mm. Based on the design requirements of the printed circuit board, the thickness of the core board dielectric 140 in the second core board 14 between the first signal layer 144 and the ground layer 142 is generally designed to be 0.1 mm. The machining error due to machining is significantly larger than the thickness of the insulation layer Therefore, if traditional machining is used, if the processing depth is deeper, the portion of the ground layer 142 that is in contact with the conductive layer 52 will be cut off, thereby disconnecting the electrical connection between the conductive layer 52 and the ground layer 142. If the processing depth is shallow, there will be a large amount of residual copper remaining between the first signal layer 144 and the ground layer 142, which will cause return loss and further affect the performance of the printed circuit board 100.

In this embodiment, the conductive layer 52 located between the ground layer 142 and the first signal layer 144 is removed by laser cutting, so as to obtain the conductive layer 52 that electrically connects the heat sink 20 and the ground layer 142.

Specifically, in this embodiment, the conductive layer 52 may be made of metallic copper. A laser pulse with a pulse energy density higher than the energy density threshold required for the copper foil material to melt or evaporate may be used to directly irradiate the end face of the copper layer away from the heat sink 20 so that the copper foil material is rapidly melted or evaporated to remove the copper foil material. The copper layer between a signal layer 144 and the ground layer 142 is removed, and only the conductive layer 52 of the ground layer 142 near the end surface of the second core board 14 remains.

In this embodiment, UV (Ultraviolet Rays) laser is used for cutting. Among them, the UV light can process the end surface of the conductive layer at a scanning speed of 50-400 mm / s. Moreover, during processing, the energy density of the UV light is 70-240 J / cm ^ 2, and the repetition frequency is 10-30 KHZ.

Of course, in other embodiments, other types of lasers can also be used for cutting, which is not specifically limited in this creation.

Exemplary embodiments of the printed circuit board 100 and a method of manufacturing the printed circuit board 100 are described in detail in this specification. The printed circuit board 100 and method are not limited to the specific embodiments described in this specification, but rather, the operations of the components and / or methods of the printed circuit board 100 may be the same as those described in this specification. Other elements and / or operations are utilized independently and separately. In addition, the elements and / or operations may be limited to or used with other systems, methods, and / or devices, and are not limited to using only the printed circuit board 100 described in this specification. Implement it.

Unless otherwise specified, the operation execution order or implementation order of the creative embodiment described in this specification is not a necessary order. That is, unless otherwise specified, the operations may be performed in any order, and embodiments of the present invention may include additional or fewer operations than those disclosed in this specification. For example, it is anticipated that performing or performing a particular operation before, simultaneously with, or after another operation is within the scope of various aspects of this creation.

The above is only an implementation of this creation, and does not therefore limit the scope of patents for this creation. Any equivalent structure or equivalent process transformation made using this creation description and graphical content, or directly or indirectly used in other related technologies The fields are equally covered by the patent protection of this creation.

Claims (20)

A printed circuit board includes a core board element including a first core board and a second core board that are sequentially stacked, and a metal layer is provided on a side of the second core board near the first core board. The first core plate is provided with a through slot penetrating through the first core plate; a heat dissipation device is at least partially accommodated in the through slot; and a conductive adhesive layer is provided on the metal layer of the second core plate And the heat dissipation device, for electrically connecting the heat dissipation device and the metal layer. The printed circuit board according to item 1 of the scope of patent application, wherein the number of the first core boards is plural, and a plurality of the first core boards are sequentially stacked; all of the plurality of the first core boards The through grooves are correspondingly arranged and cut off to the second core plate to form a receiving space for receiving the heat dissipation device; the heat dissipation device is at least partially accommodated in the receiving space. The printed circuit board according to item 1 of the scope of patent application, further comprising a first connection layer located between the first core board and the second core board and provided around the conductive adhesive layer; the The first connection layer is an adhesive material and is used for bonding the first core board and the second core board. The printed circuit board according to item 3 of the scope of patent application, wherein a maximum cross-sectional area of the through groove is greater than a maximum cross-sectional area of the heat sink, so that an outer side wall of the heat sink and the first A gap is formed between the inner side walls surrounding the through groove on the core board. The printed circuit board according to item 4 of the scope of patent application, wherein the size of the gap is 0.05 mm-0.2 mm. The printed circuit board according to item 4 of the scope of patent application, wherein a second connection layer is further provided in the gap, and the second connection layer is made of an adhesive material, and is used for connecting the heat sink and the heat sink. The first core plate is bonded. The printed circuit board according to item 6 of the scope of patent application, wherein the second connection layer and the first connection layer are an integrated structure. The printed circuit board according to item 1 of the scope of patent application, wherein a cross-sectional area of the conductive adhesive layer is smaller than or equal to an area of a surface of the heat dissipation device that is in contact with the conductive adhesive layer. The printed circuit board according to item 8 of the scope of application for a patent, wherein a groove is formed on an end surface of the heat sink in contact with the metal layer. The printed circuit board according to item 9 of the scope of patent application, wherein the cross section of the groove along the stacking direction of the first core board and the second core board is rectangular, arc-shaped, or inverted trapezoid . The printed circuit board according to item 1 of the scope of patent application, wherein a mounting groove is formed on the second core board and penetrates the second core board and is used for mounting a heating device; the mounting groove corresponds to the The heat dissipation device is arranged to pass through the conductive adhesive layer and extend to the surface or inside of the heat dissipation device, and the depth of the mounting groove is smaller than the height of the printed circuit board. The printed circuit board according to item 1 of the scope of patent application, wherein the metal layer is a ground layer; a side of the second core board facing away from the first core board is further provided with a first signal layer; The printed circuit board is further provided with a via hole extending at least from the first signal layer to the ground layer; a conductive layer electrically connecting the first signal layer and the ground layer is provided in the via hole, and For enhancing the grounding performance of the first signal layer. The printed circuit board according to item 12 of the scope of patent application, wherein the via hole extends through the conductive adhesive layer and extends to the inside of the heat dissipation device. The printed circuit board according to item 12 of the scope of patent application, wherein the via hole extends to the conductive adhesive layer and does not pass through the conductive adhesive layer and the heat sink. The printed circuit board according to item 12 of the scope of patent application, wherein the via hole extends to the inside of the heat dissipation device and does not pass through the conductive adhesive layer. The printed circuit board according to item 1 of the patent application scope, wherein a side of the first core board facing away from the second core board is provided with a metal capping layer, and the metal capping layer covers the communication groove. The printed circuit board according to item 1 of the scope of patent application, further comprising at least one third core board stacked on a side of the second core board facing away from the first core board; all third core boards A second signal layer is further disposed on a side of the third core board that is the largest distance from the second core board away from the second core board; and the printed circuit board is further provided with at least one second signal layer. A via hole extending to the ground layer; a conductive layer electrically connecting the second signal layer and the ground layer is disposed in the via hole, and is used to strengthen the grounding performance of the second signal layer. An electronic device includes a printed circuit board including a core board element including a first core board and a second core board that are sequentially stacked, and the second core board is disposed near a side of the first core board. There is a metal layer, the first core plate is provided with a through groove penetrating through the first core plate, and the second core plate is provided with a mounting groove penetrating through the second core plate; Placed in the through groove; a conductive adhesive layer is provided between the metal layer of the second core board and the first heat sink, and is used to electrically connect the first heat sink to the metal layer A connection; and a heat generating device, which is installed in the mounting groove, and a maximum cross-sectional area of the heat generating device is smaller than an area of a bottom surface of the first heat dissipation device constituting the mounting groove. The electronic device according to item 18 of the scope of patent application, wherein the heat generating device includes an electronic device and a second heat sink; the second heat sink is disposed in the mounting groove and is located in the first heat sink And the electronic device; the maximum cross-sectional area of the second heat sink is smaller than the area of the bottom surface of the first heat sink that constitutes the mounting groove. The electronic device according to item 19 of the scope of patent application, wherein the second heat dissipation device is made of a conductive material, the electronic device further includes a conductive solder material layer, and the second heat dissipation device passes the conductive solder material The layer is electrically connected to the first heat sink.