CN112566358B

CN112566358B - Preparation method of multilayer circuit board for 5G communication and multilayer circuit board thereof

Info

Publication number: CN112566358B
Application number: CN202011386776.3A
Authority: CN
Inventors: 肖学慧; 欧阳小军; 张孝斌
Original assignee: Ji'an Mankun Technology Co ltd
Current assignee: Ji'an Mankun Technology Co ltd
Priority date: 2020-12-01
Filing date: 2020-12-01
Publication date: 2021-08-13
Anticipated expiration: 2040-12-01
Also published as: CN112566358A

Abstract

A method for preparing a multilayer circuit board for 5G communication and the multilayer circuit board thereof are disclosed. The method comprises providing a substrate, forming a flow guide channel for flowing cooling medium in the substrate, arranging a first circuit layer and a second circuit layer on the top surface and the bottom surface of the substrate respectively, a plurality of through holes are drilled on the first circuit layer, the through holes sequentially penetrate through the first circuit layer, the substrate and the second circuit layer, the through holes are communicated with the flow guide channel, the heat-conducting columns are hermetically arranged in the through holes so as to electrically connect the first circuit layer and the second circuit layer, the heat-conducting columns are contacted with the cooling medium in the flow guide channels, the flow guide channels of each substrate of the multilayer circuit board are respectively connected with the condensing units through the inlets and the outlets to form cooling flow paths for circulating the cooling medium, arranging a first electronic component at least one first heat-conducting pillar on the top surface of the multilayer circuit board and adhering a first solder mask layer, a second electronic component is disposed at a second heat-conductive pillar of the bottom surface of the multilayer circuit board different from the first heat-conductive pillar and a second solder resist layer is bonded.

Description

Preparation method of multilayer circuit board for 5G communication and multilayer circuit board thereof

Technical Field

The invention relates to the technical field of 5G communication circuit boards, in particular to a preparation method of a multilayer circuit board for 5G communication and the multilayer circuit board.

Background

The fifth generation mobile communication technology (5G) has higher speed and wider bandwidth, the functions of electronic elements are more and more, the packaging volume is smaller and smaller, the surface mounting technology increases the mounting density of the electronic elements, the effective heat dissipation area is reduced, the processing capacity is stronger and stronger, the electronic elements inevitably generate more heat in the working process, the heat flow density is larger and larger, and even reaches dozens to hundreds of W/cm². These high heat or untimely heat dissipation may damage electronic components, which requires the circuit board to have high thermal conductivity and heat dissipation capability.

Conducting away or radiating away through the PCB is one of the effective ways to solve the heat dissipation problem. The PCB board is a copper-clad/epoxy glass cloth substrate or a phenolic resin glass cloth substrate, which has excellent electrical performance and processability, but has poor heat dissipation, and generally employs heat dissipation from the surface of the component to the ambient air, and circuit board components are usually radiated outward and flowed through the ambient air by heat dissipation, and other methods such as water cooling, fans, etc. are also available. In the prior art, the addition of a thermal interface to one side of the PCB to improve heat dissipation, such as a large heavy copper block, has prevented the use of a specific side of the board to add components to increase the complexity and functionality of the PCB, thereby limiting the design and use of the PCB. Moreover, copper and similar metal blocks are heavy, which may be undesirable for payload-sensitive operations, and they may become detached under rough shipping or other use conditions, thereby preventing efficient transfer of excess heat. The prior art does not transfer heat away through the PCB substrate by a heat sink in thermal communication with the overheating producing components. But this only removes heat from a single side of the PCB, e.g. fans, water cooled equipment, requiring the use of larger and heavier heat sinks to maximize the surface area in thermal communication with excess heat sources, thereby promoting better heat removal. It is still difficult to dissipate the excess heat due to the poor thermal conductivity of the PCB substrate and the limited space available for mounting the heat sink.

With the advent of 5G, the era of miniaturized, high-density mounting, and high-heat generation assembly, the heat generated by the components is largely transferred to the PCB due to the large amount of surface mount components, and the low thermal conductivity of the PCB substrate makes it difficult to remove the excessive heat from the electronic system. Thus, current prior art methods of removing excess heat from the PCB are increasingly less effective, thereby hindering the useful life and stability of the circuit board.

The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Disclosure of Invention

The present inventors have conducted intensive studies to achieve the above object, and specifically, a method for manufacturing a multilayer circuit board for 5G communication includes the steps of:

the first step, providing a substrate, forming a flow guide channel for circulating a cooling medium in the substrate, wherein an inlet and an outlet of the flow guide channel are respectively positioned on the side surface of the substrate, the side wall of the inlet is provided with a capillary flow guide structure,

a second step of respectively arranging a first circuit layer and a second circuit layer on the top surface and the bottom surface of the substrate, drilling a plurality of through holes on the first circuit layer, wherein the through holes sequentially penetrate through the first circuit layer, the substrate and the second circuit layer, the through holes are communicated with the flow guide channel, the sectional area of the flow guide channel is larger than that of the through holes,

a third step of hermetically arranging a heat conduction column in the through hole to electrically connect the first circuit layer and the second circuit layer, wherein the heat conduction column has a heat conduction coefficient larger than that of the first circuit layer or the second circuit layer and contacts the cooling medium in the flow guide channel,

a fourth step of repeating the first to third steps several times to form a multilayer circuit board having at least two substrates, two first circuit layers and two second circuit layers, the flow guide channel of each substrate being connected to the condensing unit via an inlet and an outlet, respectively, to form a cooling flow path through which a cooling medium flows, the cooling flow path being connected to a pump for pumping the cooling medium,

and a fifth step of arranging a first electronic component and bonding a first solder mask at least one first heat conduction column of the top surface of the multilayer circuit board, and arranging a second electronic component and bonding a second solder mask at a second heat conduction column different from the first heat conduction column of the bottom surface of the multilayer circuit board, wherein the first electronic component and/or the second electronic component comprise electronic components for 5G communication.

In the preparation method of the multilayer circuit board for 5G communication, in the first step, a lower half substrate is provided, a first diversion trench for circulating a cooling medium is formed on the upper surface of the lower half substrate, a capillary diversion structure is arranged on the inner wall of an inlet of the first diversion trench,

providing an upper half substrate, forming a second diversion trench for circulating a cooling medium on the lower surface of the upper half substrate, arranging a capillary diversion structure on the inner wall of an inlet of the second diversion trench, laminating the first substrate and the second substrate, wherein the first diversion trench and the second diversion trench are overlapped to form a diversion channel.

In the preparation method of the multilayer circuit board for 5G communication, the first diversion trench is paved with a heat conduction pipe, the first diversion trench and the second diversion trench are overlapped to wrap the heat conduction pipe, the heat conduction pipe forms a diversion channel for circulating a cooling medium, and the heat conduction pipe is connected with an inlet at a capillary diversion structure.

In the preparation method of the multilayer circuit board for 5G communication, in the second step, an insulating layer is pasted on the first circuit layer, the pulse carbon dioxide laser ablates the insulating layer at the position of the through hole to be drilled to expose the copper foil of the first circuit layer, the copper foil is electroplated to form a first metal enhancement layer, similarly, the insulating layer is pasted on the second circuit layer, the pulse carbon dioxide laser ablates the insulating layer at the position of the through hole to be drilled to expose the copper foil of the second circuit layer, then the second metal enhancement layer is electroplated to form a second metal enhancement layer, the pulse carbon dioxide laser drills a hole at the position of the tin layer to sequentially penetrate through the first metal enhancement layer, the first circuit layer, the substrate, the second circuit layer and the second metal enhancement layer, and finally the through hole is cleaned by ethanol.

In the method for manufacturing the multilayer circuit board for 5G communication, in the third step, the heat conducting column is a solid silver column, the solid silver column is thermally sealed in the through hole so as to be electrically connected with the first circuit layer and the second circuit layer, and the solid silver column is respectively sealed with the first circuit layer and the first metal enhancement layer thereof, the second circuit layer and the second metal enhancement layer thereof.

In the preparation method of the multilayer circuit board for 5G communication, the inlet of the flow guide channel of each substrate is connected with a pump through a first manifold, and the outlet of the flow guide channel of each substrate is connected with the pump through a second manifold.

In the preparation method of the multilayer circuit board for 5G communication, a pump for pumping cooling medium is connected in the cooling flow path, and the pump is a piezoelectric diaphragm pump, an injection pump or a peristaltic pump.

In the preparation method of the multilayer circuit board for 5G communication, the even layer or odd layer of the substrate in the multilayer circuit board is provided with a flow guide channel.

In the preparation method of the multilayer circuit board for 5G communication, the substrate comprises an organic insulating medium layer and a prepreg layer, and the flow guide channels are S-shaped channels formed by staggered groove walls uniformly distributed in the substrate.

According to another aspect of the present invention, a multilayer circuit board for 5G communication, which is manufactured via the method for manufacturing a multilayer circuit board for 5G communication.

ADVANTAGEOUS EFFECTS OF INVENTION

The method for preparing the multilayer circuit board for 5G communication of the invention is further beneficial to high-density installation by arranging the flow guide channel for circulating the cooling medium in the substrate without occupying valuable use space on the upper and lower surfaces of the multilayer circuit board and respectively arranging the inlet and the outlet of the flow guide channel on the side surface of the substrate, the side wall of the inlet is provided with the capillary flow guide structure to enhance the fluidity of the cooling medium flowing into the flow guide channel, the first circuit layer is drilled with a plurality of through holes which sequentially penetrate through the first circuit layer, the substrate and the second circuit layer, the through holes are communicated with the flow guide channel, the through holes are internally and hermetically provided with the heat conduction columns to electrically connect the first circuit layer and the second circuit layer, the heat conduction columns are contacted with the cooling medium in the flow guide channel, and the heat generated by the electronic components on the upper and lower surfaces is transferred to the cooling medium to be rapidly cooled, the sectional area of the flow guide channel is larger than that of the through hole, so that the heat conduction column is ensured to be immersed in the cooling medium, the heat conductivity coefficient of the heat conduction column is larger than that of the first circuit layer or the second circuit layer, the heat conduction efficiency is improved, the flow guide channel of each substrate is respectively connected with the condensing unit through the inlet and the outlet to form a cooling flow path for circulating the cooling medium, the cooling medium absorbing heat flows out through the cooling flow path, and new cooling medium enters the flow guide channel again through the inlet, the first electronic element and the second electronic element on the upper surface and the lower surface can be simultaneously cooled, the heat dissipation effect of the multilayer circuit board for 5G communication is obviously improved, the spatial position of the upper surface and the lower surface of the circuit board is prevented from being hindered, the design and the use of the PCB are not limited, the weight of the multilayer circuit board is not increased, and the sensitive operation of effective load is not influenced, the applicability of the multilayer circuit board is improved, and in addition, the flow guide channels of the substrates of the multilayer circuit board share one cooling flow path, so that the heat dissipation efficiency is further improved.

The above description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly apparent, and to make the implementation of the content of the description possible for those skilled in the art, and to make the above and other objects, features and advantages of the present invention more obvious, the following description is given by way of example of the specific embodiments of the present invention.

Drawings

Fig. 1 is a schematic view showing steps of a method for manufacturing a multilayer circuit board for 5G communication according to the present invention.

Fig. 2 shows a schematic structural diagram of an embodiment of a multilayer circuit board for 5G communication of the present invention.

Fig. 3 is a schematic structural view showing one embodiment of a flow guide channel of a multilayer circuit board for 5G communications according to the present invention.

Fig. 4 shows a schematic structural diagram of an embodiment of a multilayer circuit board for 5G communication of the present invention.

Detailed Description

Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It should be noted that certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, but is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present invention is defined by the appended claims.

For the purpose of facilitating an understanding of the embodiments of the present invention, the following description will be made in terms of several specific embodiments with reference to the accompanying drawings, and the drawings are not intended to limit the embodiments of the present invention.

Specifically, as shown in fig. 1, a schematic diagram of steps of a method for manufacturing a multilayer circuit board for 5G communication according to the present invention, a method for manufacturing a multilayer circuit board for 5G communication includes the steps of:

the method comprises the steps of firstly, providing a substrate 1, forming a flow guide channel 2 for circulating a cooling medium in the substrate 1, wherein an inlet 11 and an outlet 12 of the flow guide channel 2 are respectively positioned on the side surface of the substrate 1, the side wall of the inlet 11 is provided with a capillary flow guide structure,

a second step of respectively arranging a first circuit layer 3 and a second circuit layer 4 on the top surface and the bottom surface of the substrate 1, drilling a plurality of through holes 5 on the first circuit layer 3, wherein the through holes 5 sequentially penetrate through the first circuit layer 3, the substrate 1 and the second circuit layer 4, the through holes 5 are communicated with the flow guide channel 2, the sectional area of the flow guide channel 2 is larger than that of the through holes 5,

a third step of sealing and arranging a heat conduction column 6 in the through hole 5 to electrically connect the first circuit layer 3 and the second circuit layer 4, wherein the heat conduction column 6 has a heat conduction coefficient larger than that of the first circuit layer 3 or the second circuit layer 4, the heat conduction column 6 contacts the cooling medium in the flow guide channel 2,

a fourth step of repeating the first to third steps several times to form a multilayer circuit board having at least two substrates 1, two first wiring layers 3 and two second wiring layers 4, the guide channels 2 of each substrate 1 being connected to a condensing unit via an inlet 11 and an outlet 12, respectively, to form a cooling flow path through which a cooling medium flows,

a fifth step of arranging a first electronic component 7 and bonding a first solder mask at least one first heat-conducting pillar 6 of the top surface of the multilayer circuit board, and arranging a second electronic component 8 and bonding a second solder mask at a second heat-conducting pillar 6 of the bottom surface of the multilayer circuit board different from the first heat-conducting pillar 6, the first electronic component 7 and/or the second electronic component 8 including an electronic component for 5G communication.

In a preferred embodiment of the method for manufacturing a multilayer circuit board for 5G communication, in the first step, a lower half substrate 1 is provided, a first guiding groove for circulating a cooling medium is formed on the upper surface of the lower half substrate 1, and a capillary guiding structure is arranged on the inner wall of an inlet 11 of the first guiding groove.

Providing an upper half substrate 1, forming a second diversion trench for circulating a cooling medium on the lower surface of the upper half substrate 1, arranging a capillary diversion structure on the inner wall of an inlet 11 of the second diversion trench, laminating the first substrate 1 and the second substrate 1, wherein the first diversion trench and the second diversion trench are overlapped to form a diversion channel 2.

In a preferred embodiment of the method for manufacturing a multilayer circuit board for 5G communication, a heat pipe is laid on the first guiding groove, the first guiding groove and the second guiding groove are overlapped to wrap the heat pipe, the heat pipe forms a guiding channel 2 for flowing a cooling medium, and the heat pipe is connected to the inlet 11 at the capillary guiding structure.

In the second step of the method for manufacturing a multilayer circuit board for 5G communication, an insulating layer is pasted on the first circuit layer 3, the insulating layer at the position of the through hole 5 to be drilled is ablated by the pulsed carbon dioxide laser to expose the copper foil of the first circuit layer 3, the copper foil is electroplated to form the first metal enhancement layer 9, similarly, the insulating layer is pasted on the second circuit layer 4, the insulating layer at the position of the through hole 5 to be drilled is ablated by the pulsed carbon dioxide laser to expose the copper foil of the second circuit layer 4, then the second metal enhancement layer 10 is electroplated, the pulsed carbon dioxide laser drills a hole at the position of the tin layer to sequentially penetrate through the first metal enhancement layer 9, the first circuit layer 3, the substrate 1, the second circuit layer 4 and the second metal enhancement layer 10, and finally the through hole 5 is cleaned by ethanol.

In a preferred embodiment of the method for manufacturing a multilayer circuit board for 5G communication, in the third step, the heat conducting pillar 6 is a solid silver pillar, the solid silver pillar is heat sealed in the through hole 5 so as to be electrically connected with the first circuit layer 3 and the second circuit layer 4, and the solid silver pillar is respectively sealed with the first circuit layer 3 and the first metal enhancement layer 9 thereof, and the second circuit layer 4 and the second metal enhancement layer 10 thereof.

In the preferred embodiment of the method for manufacturing a multilayer circuit board for 5G communication, the inlet 11 of the flow guide channel 2 of each substrate 1 is connected to a pump via a first manifold, and the outlet 12 of the flow guide channel 2 of each substrate 1 is connected to the pump via a second manifold.

In a preferred embodiment of the method for manufacturing a multilayer circuit board for 5G communication, a pump for pumping a cooling medium is connected to the cooling flow path, and the pump is a piezoelectric diaphragm pump, a syringe pump or a peristaltic pump.

In the preferred embodiment of the preparation method of the multilayer circuit board for 5G communication, in the multilayer circuit board, the even-numbered layer or odd-numbered layer of the substrate 1 is provided with the flow guide channel 2.

In a preferred embodiment of the method for manufacturing the multilayer circuit board for 5G communication, the substrate 1 includes an organic insulating medium layer and a prepreg layer, and the flow guide channels 2 are S-shaped channels formed by staggered groove walls uniformly distributed in the substrate 1.

To further understand the present invention, as shown in fig. 2, in one embodiment, as a specific example of a multilayer circuit board, the present disclosure can also be applied to a one-layer circuit board, and a method for manufacturing a multilayer circuit board for 5G communication includes the steps of:

the first step, as shown in fig. 3, provides a substrate 1, forms a flow guide channel 2 for flowing cooling medium in the substrate 1, the inlet 11 and the outlet 12 of the flow guide channel 2 are respectively located on the side surface of the substrate 1, the side wall of the inlet 11 is provided with a capillary flow guide structure, and optionally, in a flow guide channel 2 formed inside said base plate 1 for the circulation of a cooling medium, a lower base plate half 1 is provided, a first diversion trench for circulating a cooling medium is formed on the upper surface of the lower half substrate 1, a capillary diversion structure is arranged on the inner wall of an inlet 11 of the first diversion trench to provide an upper half substrate 1, a second diversion trench for circulating a cooling medium is formed on the lower surface of the upper half substrate 1, a capillary diversion structure is arranged on the inner wall of an inlet 11 of the second diversion trench, and the first substrate 1 and the second substrate 1 are laminated, wherein the first diversion trench and the second diversion trench are overlapped to form a diversion channel 2. Further, in order to improve the heat dissipation effect, especially for the area without the through hole 5, a heat pipe is laid on the first guiding groove, the first guiding groove and the second guiding groove are overlapped to wrap the heat pipe, the heat pipe forms a guiding channel 2 for flowing a cooling medium, and the heat pipe is connected with the inlet 11 at the capillary guiding structure. The heat conductivity coefficient of the heat conduction pipe is larger than that of the substrate 1, so that the heat of the substrate 1 can be guided into the flow guide channel 2. It is understood that the cooling medium is a cooling medium that is not electrically conductive. Alternatively, the substrate 1 may be formed of an organic resin such as an epoxy resin, a bisimide-triazine resin, a polyimide resin, a polyphenylene ether resin, or two or more kinds of organic resins may be mixed. Further, the substrate 1 includes a reinforcing material of glass fiber, glass nonwoven fabric, and aramid.

In the second step, the first wiring layer 3 and the second wiring layer 4 are provided on the top surface and the bottom surface of the substrate 1, respectively, and the first wiring layer 3 and the second wiring layer 4 form a conductor circuit via, for example, conductive resin or metal plating, but copper plating, copper plating being copper plating, may be electroless copper plating, is particularly preferable from the viewpoint of convenience of processing such as etching. Drilling a plurality of through holes 5 on the first circuit layer 3, wherein the through holes 5 sequentially penetrate through the first circuit layer 3, the substrate 1 and the second circuit layer 4, the through holes 5 are communicated with the flow guide channel 2, the sectional area of the flow guide channel 2 is larger than that of the through holes 5, and optionally, the sections of the flow guide channel 2 and the through holes 5 are circular, rectangular, rounded rectangular, oval or other geometric shapes. Alternatively, in drilling a plurality of through holes 5 on the first wiring layer 3, an insulating layer is pasted on the first wiring layer 3, a pulsed carbon dioxide laser ablates the insulating layer at the positions of the through holes 5 to be drilled to expose the copper foil of the first wiring layer 3, the copper foil is electroplated with a tin layer to form a tin-copper layer, similarly, an insulating layer is pasted on the second wiring layer 4, a pulsed carbon dioxide laser ablates the insulating layer at the positions of the through holes 5 to be drilled to expose the copper foil of the second wiring layer 4, then the tin-copper layer is electroplated to form a tin-copper layer, a pulsed carbon dioxide laser drills holes at the positions of the tin layer to sequentially penetrate through the first metal reinforcing layer 9 of the tin-copper layer, the first wiring layer 3, the substrate 1, the second wiring layer 4 and the second metal reinforcing layer 10 of the tin-copper layer, and finally the through holes 5 are cleaned by ethanol. The first metal enhancement layer 10 and the second metal enhancement layer 10 which form the copper-tin layer not only improve the sealing effect of the heat conduction column 6 and enhance the conductivity, but also are beneficial to the effectiveness of 5G high-frequency signals.

And thirdly, hermetically arranging a heat conduction column 6 in the through hole 5 to electrically connect the first circuit layer 3 and the second circuit layer 4, wherein the heat conduction column 6 is respectively sealed with the first circuit layer 3 and the first metal enhancement layer 9 thereof, the second circuit layer 4 and the second metal enhancement layer 10 thereof, the heat conduction coefficient of the heat conduction column 6 is greater than that of the first circuit layer 3 or the second circuit layer 4, and the heat conduction column 6 is in contact with the cooling medium in the flow guide channel 2. Optionally, to further increase the sealing performance, the inner wall of the through hole 5 is provided with an internal thread, and correspondingly, the outer surface of the heat conducting column 6 is provided with a corresponding external thread.

In the fourth step, the flow guide channels 2 of the substrate 1 are respectively connected with a condensing unit via an inlet 11 and an outlet 12 to form a cooling flow path through which a cooling medium flows, and optionally, a pump for pumping the cooling medium is connected in the cooling flow path, wherein the pump is a piezoelectric diaphragm pump, a syringe pump or a peristaltic pump. The pump is a micro-direct-current pump, which can be arranged in the circuit board side space as required. Further, the cooling flow path is provided with a condenser comprising a serpentine coil.

As shown in fig. 4, in one embodiment, a method for manufacturing a multilayer circuit board for 5G communication includes the steps of:

the method comprises the following steps of providing a lower half base plate 1, forming a first diversion trench for circulating a cooling medium on the upper surface of the lower half base plate 1, extending the first diversion trench in parallel with the lower surface of the lower half base plate 1, providing an upper half base plate 1 by arranging a capillary diversion structure on the inner wall of an inlet 11 of the first diversion trench, forming a second diversion trench for circulating the cooling medium on the lower surface of the upper half base plate 1, extending the second diversion trench in parallel with the upper surface of the upper half base plate 1, arranging the capillary diversion structure on the inner wall of the inlet 11 of the second diversion trench, and laminating the first base plate 1 and the second base plate 1, wherein the first diversion trench and the second diversion trench are overlapped to form a diversion channel 2. Further, in order to improve the heat dissipation effect, especially for the area without the through hole 5, a heat pipe is laid on the first guiding groove, the first guiding groove and the second guiding groove are overlapped to wrap the heat pipe, the heat pipe forms a guiding channel 2 for flowing a cooling medium, and the heat pipe is connected with the inlet 11 at the capillary guiding structure. The heat conductivity coefficient of the heat conduction pipe is larger than that of the substrate 1, so that the heat of the substrate 1 can be guided into the flow guide channel 2. It is understood that the cooling medium is a cooling medium that is not electrically conductive. Alternatively, the substrate 1 may be formed of an organic resin such as an epoxy resin, a bisimide-triazine resin, a polyimide resin, a polyphenylene ether resin, or two or more kinds of organic resins may be mixed. Further, the substrate 1 includes a reinforcing material of glass fiber, glass nonwoven fabric, and aramid.

In the second step, the first wiring layer 3 and the second wiring layer 4 are provided on the top surface and the bottom surface of the substrate 1, respectively, and the first wiring layer 3 and the second wiring layer 4 form a conductor circuit via, for example, conductive resin or metal plating, but copper plating, copper plating being copper plating, may be electroless copper plating, is particularly preferable from the viewpoint of convenience of processing such as etching. Adhering an insulating layer on the first circuit layer 3, etching the insulating layer at the position of the through hole 5 to be drilled by a pulse carbon dioxide laser to expose the copper foil of the first circuit layer 3, forming a copper-tin layer by the copper foil electrotinning layer, similarly adhering an insulating layer on the second circuit layer 4, etching the insulating layer at the position of the through hole 5 to be drilled by a pulse carbon dioxide laser to expose the copper foil of the second circuit layer 4, then forming a copper-tin layer by the electrotinning layer, drilling a hole at the position of the tin layer by the pulse carbon dioxide laser to sequentially penetrate through the first metal reinforcing layer 9 of the copper-tin layer, the first circuit layer 3, the substrate 1, the second circuit layer 4 and the second metal reinforcing layer 10 of the copper-tin layer, and finally cleaning the through hole 5 by ethanol. The first metal enhancement layer 10 and the second metal enhancement layer 10 which form the copper-tin layer not only improve the sealing effect of the heat conduction column 6 and enhance the conductivity, but also are beneficial to the effectiveness of 5G high-frequency signals.

And thirdly, hermetically arranging a heat conduction column 6 in the through hole 5 to electrically connect the first circuit layer 3 and the second circuit layer 4, wherein the heat conduction column 6 is respectively sealed with the first circuit layer 3 and the first metal enhancement layer 9 thereof, the second circuit layer 4 and the second metal enhancement layer 10 thereof, the heat conduction coefficient of the heat conduction column 6 is greater than that of the first circuit layer 3 or the second circuit layer 4, and the heat conduction column 6 is in contact with the cooling medium in the flow guide channel 2. Alternatively, the thermally conductive post 6 may or may not be in electrical communication with an electrically conductive trace or other component defining a printed circuit. Thus, the operation of the thermal post 6 relative to the printed circuit board may be functional, non-functional, or any combination thereof.

And a fourth step of repeating the first step to the third step for a plurality of times to form a multilayer circuit board, wherein the multilayer circuit board has a plurality of substrates 1, a plurality of first circuit layers 3 and a plurality of second circuit layers 4, the flow guide channel 2 of each substrate 1 is connected with a condensing unit via an inlet 11 and an outlet 12 to form a cooling flow path for circulating a cooling medium, optionally, the same heat conduction column 6 penetrates from the upper surface to the lower surface of the multilayer circuit board, or the same heat conduction column 6 only penetrates through the substrate 1 where the same heat conduction column 6 is located, or a part of the heat conduction columns 6 penetrate through the upper surface to the lower surface of the multilayer circuit board, and the other part of the heat conduction columns 6 only penetrates through the substrate 1 where the same heat conduction column 6 is located.

A fifth step of arranging a first electronic component 7 and bonding a first solder mask at least one first heat-conducting pillar 6 of the top surface of the multilayer circuit board, and arranging a second electronic component 8 and bonding a second solder mask at a second heat-conducting pillar 6 of the bottom surface of the multilayer circuit board different from the first heat-conducting pillar 6, the first electronic component 7 and the second electronic component 8 including electronic components for 5G communication.

The multilayer circuit board for 5G communication is manufactured by the preparation method of the multilayer circuit board for 5G communication.

Industrial applicability

The preparation method of the multilayer circuit board for 5G communication and the multilayer circuit board thereof can be used in the field of 5G communication circuit boards.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.

Claims

1. A preparation method of a multilayer circuit board for 5G communication is characterized by comprising the following steps:

a second step of respectively providing a first line layer and a second line layer on the top surface and the bottom surface of the substrate, drilling a plurality of through holes on the first line layer, wherein the through holes sequentially penetrate through the first line layer, the substrate and the second line layer, the through holes are communicated with the diversion channels, the sectional areas of the diversion channels are larger than the sectional areas of the through holes, wherein an insulating layer is pasted on the first line layer, the insulating layer at the through holes to be drilled is burnt by pulse carbon dioxide laser to expose the copper foil of the first line layer, the copper foil is electroplated to form a first metal enhancement layer, similarly, the insulating layer is pasted on the second line layer, the insulating layer at the through holes to be drilled is burnt by the pulse carbon dioxide laser to expose the copper foil of the second line layer, and then a second metal enhancement layer is electroplated to form, and the pulse carbon dioxide laser drills at the positions of the first metal enhancement layer to sequentially penetrate through the first metal enhancement layer, The first circuit layer, the substrate, the second circuit layer and the second metal enhancement layer, and finally cleaning the through hole by ethanol,

2. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: in the first step, a lower semi-base plate is provided, a first diversion trench for circulating a cooling medium is formed on the upper surface of the lower semi-base plate, a capillary diversion structure is arranged on the inner wall of an inlet of the first diversion trench,

3. The method for manufacturing a multilayer circuit board for 5G communication according to claim 2, wherein: the heat conduction pipe is laid on the first diversion trench, the first diversion trench and the second diversion trench are overlapped to wrap the heat conduction pipe, the heat conduction pipe forms a diversion channel for circulating a cooling medium, and the heat conduction pipe is connected with an inlet at the capillary diversion structure.

4. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: and a third step of sealing the solid silver column in the through hole so as to electrically connect the solid silver column with the first circuit layer and the second circuit layer, wherein the solid silver column is respectively sealed with the first circuit layer and the first metal enhancement layer thereof, the second circuit layer and the second metal enhancement layer thereof.

5. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: the inlet of the flow guide channel of each substrate is connected with a pump through a first manifold, and the outlet of the flow guide channel of each substrate is connected with the pump through a second manifold.

6. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: the pump is a piezoelectric diaphragm pump, an injection pump or a peristaltic pump.

7. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: in the multilayer circuit board, the even-numbered layer or the odd-numbered layer of the substrate is provided with a flow guide channel.

8. The method for manufacturing a multilayer circuit board for 5G communication according to claim 1, wherein: the substrate comprises an organic insulating medium layer and a prepreg layer, and the flow guide channels are S-shaped channels formed by staggered groove walls uniformly distributed in the substrate.

9. A multilayer circuit board for 5G communication, characterized in that the multilayer board is produced via the multilayer circuit board for 5G communication production method of any one of claims 1 to 8.