CN115623667A

CN115623667A - Printed circuit board with embedded heat dissipation block and manufacturing method thereof

Info

Publication number: CN115623667A
Application number: CN202211348727.XA
Authority: CN
Inventors: 余为勇; 付凤奇; 刘锋; 郭权
Original assignee: Shenzhen Kinwong Electronic Co Ltd
Current assignee: Shenzhen Kinwong Electronic Co Ltd
Priority date: 2022-10-31
Filing date: 2022-10-31
Publication date: 2023-01-17

Abstract

The application relates to the technical field of circuit boards and discloses a printed circuit board with a heat dissipation block embedded therein and a manufacturing method thereof. The printed circuit board comprises a substrate and a heat dissipation block; the substrate is provided with a through hole, the radiating block comprises a main body and a plurality of bulges which are distributed at intervals along the circumferential direction of the main body, the radiating block comprises a printing surface and a pad surface which are opposite, the radiating block is arranged in the through hole, the bulges are abutted against the hole wall of the through hole, a glue accommodating gap is formed between the main body and the hole wall of the through hole, and the printing surface and the pad surface are respectively exposed on two opposite surfaces of the substrate; the glue containing gap is filled with heat conducting glue, and the printing surface is coated with the heat conducting glue. The application provides a printed circuit board with embedded heat dissipation blocks and a manufacturing method thereof, which are used for solving the technical problem that the plate heat conduction glue in related products is not flat.

Description

Printed circuit board with embedded heat dissipation block and manufacturing method thereof

Technical Field

The application relates to the technical field of circuit boards, in particular to a printed circuit board with embedded heat dissipation blocks and a manufacturing method thereof.

Background

With the rapid development of electronic products in the direction of light weight, thinness, miniaturization and high integration, higher requirements are put forward on the heat-conducting property of the printed circuit board. The design of the current circuit board usually adopts a mode of combining an embedded radiating block with printed heat conducting glue so as to solve the radiating problem of the circuit board. However, the existing manufacturing process has more problems, for example, the heat dissipation block is embedded in the mounting hole of the circuit board, and a gap exists between the heat dissipation block and the wall of the mounting hole, on one hand, the gap has adhesive storage capacity, and the problem of adhesive surface depression is easy to occur during subsequent printing of heat-conducting adhesive on the board surface, so that the flatness of the board surface is difficult to ensure; on the other hand, the gap is not filled fully, so that a cavity appears, and the reliability of a circuit board product is influenced.

Disclosure of Invention

The application aims to provide a printed circuit board with embedded heat dissipation blocks and a manufacturing method thereof, and aims to solve the technical problem that the plate heat conduction glue in related products is uneven.

In order to solve the above problem, in a first aspect, the present application provides a printed circuit board with a heat sink embedded therein, including:

the substrate is provided with a through hole;

the radiating block comprises a main body and a plurality of bulges which are distributed at intervals along the circumferential direction of the main body, the radiating block comprises a printing surface and a welding pad surface which are opposite, the radiating block is arranged in the through hole, the bulges are abutted against the hole wall of the through hole, a glue accommodating gap is formed between the main body and the hole wall, and the printing surface and the welding pad surface are respectively exposed on two opposite surfaces of the substrate;

the glue containing gap is filled with heat conducting glue, and the printing surface is coated with the heat conducting glue.

In some embodiments, the heat sink block is a metal block or a ceramic block.

The application provides a printed circuit board with a built-in radiating block, which comprises a substrate and the radiating block, wherein the substrate is provided with a through hole, the radiating block is arranged in the through hole, a bulge of the radiating block abuts against the hole wall of the through hole, a glue containing gap is formed between the main body of the radiating block and the hole wall, heat conducting glue is filled in the glue containing gap, and the printing surface of the radiating block is coated with the heat conducting glue; on the other hand, hold to fill in gluey clearance and have filled heat-conducting glue, satisfy clearance position and fill out gluey degree of depth and plumpness requirement, coat in the heat-conducting glue on the printing face can not sink into down in holding gluey clearance to can ensure the reliability of board face roughness and circuit board product.

In a second aspect, the present application provides a method for manufacturing a printed circuit board with an embedded heat dissipation block, which is used for manufacturing the printed circuit board with an embedded heat dissipation block in the first aspect, and includes:

providing a substrate, and drilling a through hole on the substrate;

installing a heat dissipation block into the through hole;

filling heat-conducting glue into the glue accommodating gap;

and coating heat-conducting glue on the printing surface of the heat dissipation block.

In some embodiments, the filling the heat conductive glue into the glue accommodating gap includes: and filling a first heat-conducting glue and a second heat-conducting glue into the glue accommodating gap in sequence, wherein the viscosity of the first heat-conducting glue is less than that of the second heat-conducting glue.

In some embodiments, the volume ratio of the first heat-conducting glue to the second heat-conducting glue is 1.

In some embodiments, before or after the thermal paste is coated on the printed surface of the heat dissipation block, the manufacturing method further includes: and enabling the printing surface to face downwards, and baking and curing the heat-conducting glue in the glue accommodating gap.

In some embodiments, before filling the heat conductive paste in the paste accommodating gap, the manufacturing method further includes: and manufacturing a protective film on the bonding pad surface, so that the protective film covers the hole of the through hole on the side of the bonding pad surface.

In some embodiments, before filling the heat conductive paste into the paste accommodating gap, the manufacturing method further includes: and providing a plugged plate and covering the plugged plate on the printing surface, wherein the plugged plate is provided with a glue filling hole, and the glue filling hole is opposite to the glue accommodating gap.

In some embodiments, after the drilling the through hole on the substrate, the manufacturing method further includes: and performing hole metallization treatment on the through hole to enable the hole wall of the through hole to cover the first metal layer.

In some embodiments, after the heat dissipation block is installed in the through hole, the manufacturing method further includes: and performing hole metallization treatment on the through hole and the heat dissipation block to enable the surfaces of the first metal layer and the heat dissipation block to cover the second metal layer.

The application provides a manufacturing method of embedded radiating block's printed circuit board, printed circuit board's preparation flow has been optimized, fill heat-conducting glue in the appearance clearance that radiating block and pore wall formed earlier, again at the printing face coating heat-conducting glue of radiating block, can make the filling glue degree of appearance clearance degree of filling and the plumpness satisfy the requirement, thereby heat-conducting glue that coats on the printing face does not sink into down in the appearance clearance of gluing, thus, can ensure the reliability of plate face roughness and circuit board product on the one hand, on the other hand, can also improve the heat conduction contact effect between radiating block and base plate, and then the radiating block can assist the quick heat dissipation of base plate.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a printed circuit board according to an embodiment of the present disclosure;

fig. 2 is a second schematic structural diagram of a printed circuit board according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a hole plugging aluminum sheet provided in an embodiment of the present application;

fig. 4 is a schematic structural view of a screen for plugging holes provided in an embodiment of the present application;

fig. 5 is a flowchart of a manufacturing method according to an embodiment of the present disclosure;

fig. 6 is a second flowchart of a manufacturing method according to an embodiment of the present application.

Description of the main element symbols:

100. a printed circuit board;

1. a substrate; 11. a through hole; 2. a heat dissipating block; 21. a main body; 22. a protrusion; 23. printing surface; 24. a soldering land surface; 3. glue accommodating gaps; 4. heat conducting glue; 5. plugging an aluminum sheet; 51. a flow-through hole; 6. plugging a screen printing plate; 61. and (6) windowing.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly or indirectly secured to the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The terms "upper", "lower", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, are not to be construed as limiting the patent. The terms "first", "second" and "first" are used merely for descriptive purposes and are not to be construed as indicating or implying relative importance or to implicitly indicate a number of technical features. The meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference throughout this specification to "one embodiment," "some embodiments," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather mean "one or more but not all embodiments" unless specifically stated otherwise. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In a first aspect, as shown in fig. 1 and 2, the present application provides a heat slug embedded printed circuit board 100, which includes a substrate 1 and a heat slug 2. The substrate 1 is provided with a through hole 11. The radiating block 2 comprises a main body 21 and a plurality of protrusions 22 distributed around the main body 21 at intervals in the circumferential direction, the radiating block 2 comprises opposite printing surfaces 23 and pad surfaces 24, the radiating block 2 is arranged in the through hole 11, the protrusions 22 abut against the hole wall of the through hole 11, glue accommodating gaps 3 are formed between the main body 21 and the hole wall of the through hole 11, and the printing surfaces 23 and the pad surfaces 24 are respectively exposed on two opposite surfaces of the substrate 1. The glue containing gap 3 is filled with heat conducting glue 4, and the printing surface 23 is coated with the heat conducting glue 4.

The substrate 1 includes a heat dissipation area, the through holes 11 are disposed in the heat dissipation area and penetrate through two opposite surfaces of the substrate 1, and the number and the arrangement positions of the through holes 11 need to be designed according to the heat dissipation requirement and the wiring condition of the substrate 1, which is not limited herein.

The radiating block 2 is a tooth-shaped column and is arranged in the through hole 11 in an interference fit mode, the protrusions 22 of the radiating block 2 are abutted to the hole wall of the through hole 11, and a gap 3 is formed between each two adjacent protrusions 22 and can be in contact with the hole wall of the through hole 11. The inner wall of the through hole 11 is usually plated with a metal layer, and the protrusion 22 of the heat dissipation block 2 abuts against the hole wall, so that the heat dissipation block can be electrically connected with the hole wall.

The height of the heat spreader 2 is equal to the thickness of the substrate 1, and both the printing surface 23 and the land surface 24 are exposed on the surface of the substrate 1 after the heat spreader 2 is mounted in the through hole 11.

The application provides a printed circuit board 100 with a built-in radiating block, which comprises a substrate 1 and a radiating block 2, wherein the substrate 1 is provided with a through hole 11, the radiating block 2 is arranged in the through hole 11, a bulge 22 of the radiating block 2 abuts against the hole wall of the through hole 11, a glue accommodating gap 3 is formed between a main body 21 of the radiating block 2 and the hole wall, the glue accommodating gap 3 is filled with a heat conducting glue 4, and a printing surface 23 of the radiating block 2 is coated with the heat conducting glue 4; on the other hand, hold and fill in the clearance 3 and glue 4, satisfy clearance position filling degree of depth and plumpness requirement, coat in the printing face 23 on heat conduction glue 4 can not sink into down and hold in the clearance 3 of gluing to can ensure the reliability of board surface roughness and circuit board product.

The structure of the heat dissipation block 2 is not limited to this, and the heat dissipation block 2 may also have a special-shaped structure such as a triangular prism, which is not limited herein.

In the embodiments provided in the present application, the heat dissipation block 2 is a metal block or a ceramic block.

Optionally, in some embodiments, the heat dissipation block 2 is a copper block or an aluminum block. The metal block has excellent heat conducting performance and electric conducting performance, high hardness and less breaking.

Optionally, in some embodiments, the heat slug 2 is aluminum nitride or aluminum oxide. The ceramic block has good heat-conducting property, fast heat dissipation, high stability and difficult oxidation.

In the embodiment provided by the application, the heat dissipation block 2 is installed in the through hole 11 in an interference fit manner, and in the direction parallel to the surface of the substrate 1, the diameter of the position where the protrusion 22 is arranged on the heat dissipation block 2 is larger than the inner diameter of the through hole 11, and optionally, the difference between the diameter and the inner diameter is 50-75 μm.

In the embodiment that this application provided, hold and glue the heat conduction of filling two kinds of different viscosities in clearance 3 and glue 4, the heat conduction that is close to the one side packing viscosity of welding disc face 24 less relatively glues 4, the heat conduction that is close to one side packing viscosity of 2 printing faces 23 of radiating block and glues 4 great relatively.

When filling heat-conducting glue 4, need follow printing face 23 one side to holding to glue 3 in the clearance and glue, because the heat-conducting glue 4 mobility that the viscosity is littleer is also better, thereby fill the heat-conducting glue 4 that the viscosity is littleer earlier, can ensure that heat-conducting glue 4 can flow to pad face 24 one side fast, and can ensure that heat-conducting glue 4 fully fills the clearance position, especially protruding 22 and the contained angle position department that forms between the through-hole 11 pore wall. After filling heat-conducting glue 4 in glue clearance 3, still need be at printing face 23 one side coating heat-conducting glue 4 to need toast the solidification treatment to holding heat-conducting glue 4 in the glue clearance 3, being close to printing face 23 one side great heat-conducting glue 4 of viscosity of filling, follow-up glue the face and be difficult for taking place sunken when the face coating heat-conducting glue 4 degree of difficulty is low and toasts, be favorable to keeping the face level and smooth.

Further, the heat-conducting glue 4 with low viscosity is set as a first heat-conducting glue, the heat-conducting glue 4 with high viscosity is set as a second heat-conducting glue, the filling depth and the saturation of the first heat-conducting glue are controlled to be 50% -75%, that is, the volume ratio of the first heat-conducting glue to the second heat-conducting glue is 1-3.

By adopting the design, the filling proportion of the first heat-conducting glue is controlled, namely the glue filling amount in the manufacturing process is controlled, so that the risk of overflowing of the heat-conducting glue 4 from the glue gap 3 can be effectively reduced, and the pollution to the surface of the substrate 1 and the end surface of the radiating block 2 is avoided.

Further, the viscosity of the first heat-conducting glue and the viscosity of the second heat-conducting glue are designed according to specific conditions. Optionally, in an embodiment, the viscosity of the first thermally conductive paste is 500dpa.s, and the viscosity of the second thermally conductive paste is 700dpa.s.

It should be noted that, because the heat-conducting glue 4 has viscosity and fluidity, after the first heat-conducting glue and the second heat-conducting glue are filled in the glue accommodating gap 3, no regular layering line occurs. In addition, the viscosity of the heat-conducting glue 4 coated on the printing surface 23 can be designed according to actual design requirements, and the viscosity of the heat-conducting glue 4 in the glue accommodating gap 3 has no specific relation with the viscosity of the heat-conducting glue 4 on the board surface.

In the embodiment provided by the application, the printing surface 23 of the heat dissipation block 2 is coated with the heat conductive adhesive 4 for assisting the heat dissipation block 2 in heat dissipation. In order to further improve the heat dissipation effect, optionally, the heat conductive adhesive 4 covers both the printing surface 23 of the heat dissipation block 2 and the surface of the substrate 1 around the heat dissipation block 2, so as to further enlarge the heat dissipation surface.

In the embodiment provided by the application, the thickness of the heat conducting glue 4 coated on the printing surface 23 of the heat dissipation block 2 is 125 μm-175 μm.

In conclusion, the application provides an embedded radiating block's printed circuit board 100, through holding to glue the 3 intussuseption of clearance and having filled heat-conducting glue 4, solved the uneven problem of relevant product face to the radiating effect and the reliability of circuit board product have effectively been improved.

In a second aspect, the present application provides a method for manufacturing a heat slug embedded printed circuit board 100 in the first aspect, as shown in fig. 1, 2 and 5, the method includes:

s11, providing a substrate 1, and drilling a through hole 11 on the substrate 1.

The substrate 1 includes a heat dissipation region, the through holes 11 are disposed in the heat dissipation region and penetrate through two opposite surfaces of the substrate 1, and the number and the disposition positions of the through holes 11 need to be designed according to the heat dissipation requirement and the wiring condition of the substrate 1, which is not limited herein.

S12, installing the heat dissipation block 2 into the through hole 11.

The radiating block 2 comprises a main body 21 and a plurality of protrusions 22 which are distributed around the main body 21 at intervals in the circumferential direction, the radiating block 2 is arranged in the through hole 11, the protrusions 22 abut against the hole wall of the through hole 11, glue containing gaps 3 are formed between the main body 21 and the hole wall of the through hole 11, specifically, gaps are formed between the adjacent protrusions 22, and the glue containing gaps 3 can be formed between the adjacent protrusions 22 and the hole wall of the through hole 11.

The radiating block 2 is arranged in the through hole 11 in an interference fit manner, and the diameter of the position of the radiating block 2 provided with the bulge 22 is larger than the inner diameter of the through hole 11 in the direction parallel to the board surface of the substrate 1, and optionally, the difference between the diameters is 50-75 μm.

The heat dissipating block 2 includes two opposite ends, which are a printed surface 23 and a land surface 24. The length of the heat spreader 2 is equal to the thickness of the substrate 1, and both the printing surface 23 and the land surface 24 are exposed on the surface of the substrate 1 after the heat spreader 2 is mounted in the through hole 11.

The heat dissipation block 2 can be installed in the through hole 11 by a manual or automatic device, which is not limited herein.

And S13, filling the heat-conducting glue 4 into the glue containing gap 3.

When the heat-conducting glue 4 is filled, the filling depth and the fullness of the heat-conducting glue 4 are ensured to meet the requirements.

And S14, coating the heat-conducting glue 4 on the printing surface 23 of the heat dissipation block 2.

When the printing surface 23 is coated with the heat conductive adhesive 4, the printing screen can be used to assist in printing the heat conductive adhesive 4. The thickness of the heat-conducting glue 4 is 125-175 μm, and the thickness of the heat-conducting glue 4 can be controlled by adjusting parameters such as printing pressure, printing speed, scraper angle and the like.

The heat conductive glue 4 covers at least the printed surface 23 of the heat dissipation block 2, and optionally, in some embodiments, to improve the heat dissipation effect, the heat conductive glue 4 covers both the printed surface 23 of the heat dissipation block 2 and the surface of the substrate 1 around the heat dissipation block 2, so as to further enlarge the heat dissipation surface.

The method for manufacturing the printed circuit board with the embedded heat dissipation block optimizes the manufacturing process of the printed circuit board 100, fills the heat-conducting glue 4 in the glue accommodating gap 3 formed by the heat dissipation block 2 and the hole wall, coats the heat-conducting glue 4 on the printing surface 23 of the heat dissipation block 2, can enable the glue filling depth and the fullness of the glue accommodating gap 3 to meet the requirements, so that the heat-conducting glue 4 coated on the printing surface 23 cannot sink into the glue accommodating gap 3,

so, can ensure the reliability of plane roughness and circuit board product on the one hand, on the other hand can also improve the heat conduction contact effect between radiating block 2 and base plate 1, and then radiating block 2 can assist base plate 1 to dispel the heat fast.

In the embodiment provided by the present application, step S13 includes: and filling the glue accommodating gap 3 with first heat-conducting glue and second heat-conducting glue in sequence, wherein the viscosity of the first heat-conducting glue is less than that of the second heat-conducting glue.

Specifically, the printing surface 23 is filled with glue in the glue containing gap 3, and then a proper amount of first heat-conducting glue is filled, and then the remaining space is filled with second heat-conducting glue.

Because the mobility of the heat conduction glue 4 that the viscosity is littleer is also better, fill the first heat conduction glue that viscosity is littleer earlier, can ensure that heat conduction glue 4 can flow to the pad one side fast to can ensure that heat conduction glue 4 fully fills the clearance position, especially the contained angle position department that forms between 2 protruding 22 of radiating block and the through-hole 11 pore wall. Hold 3 intussuseptions in the gluey clearance and fill the heat conduction and glue 4 backs, still need glue 23 coatings of printing face and glue 4, glue the great second heat conduction of viscosity and glue near 23 one sides of printing face, can further reduce and hold gluey 3 interior gluey face sunken risks of clearance, follow-up 4 degrees of difficulty low at face coating heat conduction glue, be favorable to keeping the face level and smooth.

The viscosity of the first heat-conducting glue and the viscosity of the second heat-conducting glue are designed according to specific conditions. Optionally, in an embodiment, the viscosity of the first thermally conductive paste is 500dpa.s, and the viscosity of the second thermally conductive paste is 700dpa.s.

It should be noted that, because the heat-conducting glue 4 has viscosity and fluidity, after the first heat-conducting glue and the second heat-conducting glue are filled in the glue accommodating gap 3, no regular layering line occurs. In addition, it should be noted that the viscosity of the thermal conductive paste 4 coated on the printing surface 23 can be designed according to actual design requirements, and the viscosity of the thermal conductive paste 4 in the paste accommodating gap 3 has no specific relationship with the viscosity of the thermal conductive paste 4 on the plate surface.

In the embodiment provided by the application, a first heat-conducting glue and a second heat-conducting glue are sequentially filled in the glue accommodating gap 3, and the volume ratio of the first heat-conducting glue to the second heat-conducting glue is 1-3.

Specifically, first heat-conducting glue is filled in the glue accommodating gap 3, the filling depth and the fullness of the first heat-conducting glue are controlled to be 50% -75%, and then second heat-conducting glue is filled in the glue accommodating gap 3 and is filled in the glue accommodating gap 3.

It should be noted that, the heat-conducting glue 4 is usually stored in a frozen state, and therefore, when the glue accommodating gap 3 is filled with the heat-conducting glue 4, the heat-conducting glue 4 needs to be taken out of the refrigerator and thawed, and the heat-conducting glue 4 can be put into use after the parameters such as viscosity, temperature and the like are qualified. When the heat-conducting glue 4 is filled, automatic equipment such as a glue filling jig is used for assisting glue filling, and parameters such as scraper pressure, scraper advancing speed and scraper angle of the glue filling can be adjusted. Optionally, in one embodiment, the blade pressure is set to 8kg/cm ² Setting the moving speed of the scraper to be 45mm/sec-60mm/sec, setting the angle of the scraper to be 15-20 degrees, and after the glue filling is finished, arranging the substrate1 is placed on a suspended plate rack for temporary storage.

In an embodiment provided by the present application, before or after step S14, the manufacturing method further includes: and (4) baking and curing the heat-conducting glue 4 in the glue accommodating gap 3 with the printing surface 23 facing downwards.

On one hand, the second heat-conducting glue close to the printing surface 23 is high in viscosity, small in liquidity and better in stability during baking, and is not easy to dent at the outlet of the glue accommodating gap 3 when placed downwards; on the other hand, the first heat-conducting glue close to the welding pad surface 24 is low in viscosity and high in flowability, the printing surface 23 is arranged downwards, the first heat-conducting glue flows downwards under the action of gravity, and the second heat-conducting glue is blocked under the first heat-conducting glue, so that the first heat-conducting glue and the second heat-conducting glue can be filled in each gap position in the glue accommodating gap 3 more fully.

In some embodiments, after the glue accommodating gap 3 is filled with the thermal conductive glue 4, baking is performed before step S14 to cure the thermal conductive glue 4 in the glue accommodating gap 3, and after step S14, baking is performed again to cure the thermal conductive glue 4 on the printing surface 23.

In some embodiments, after the glue containing gap 3 is filled with the thermal conductive glue 4, baking is performed after step S14 to simultaneously cure the thermal conductive glue 4 in the glue containing gap 3 and on the printing surface 23.

In an embodiment provided by the present application, before step S13, the manufacturing method further includes: a protective film is formed on the land surface 24 so as to cover the opening of the through hole 11 on the side of the land surface 24.

The protective film is a peelable high-temperature resistant protective film, and can be a PI film or a PET film. The protective film comprises a film layer and an adhesive layer, wherein the adhesive layer has viscosity and can be tightly attached to the pad surface 24 of the heat dissipation block 2 or the surface of the substrate 1, and the adhesive layer is partially filled in the glue accommodating gap 3 to seal the glue accommodating gap 3.

When the protective film is manufactured, the protective film can be attached to a preset position, and then hot pressing and fixing are carried out by utilizing a quick press.

Adopt above-mentioned design, through setting up the protection film, can effectively block up the appearance of 24 one sides of weld disc face and glue clearance 3 to can avoid holding the heat conduction glue 4 overflows to weld disc face 24 in gluing clearance 3, make weld disc face 24 and base plate 1 surface can keep clean, follow-up welding is not influenced.

After the underfill is completed, the protective film needs to be removed. It will be appreciated that in some embodiments, the method of fabrication includes a baking step, and the protective film may be removed after the underfill, before the baking, or may be removed after the underfill and the baking.

In an embodiment provided by the present application, before step S13, the manufacturing method further includes: and providing a plugging hole plate and covering the plugging hole plate on the printing surface 23, wherein the plugging hole plate is provided with a glue filling hole which is opposite to the glue containing gap 3.

In particular, the sheet of plugging material covers the printing surface 23, being able to protect the printing surface 23 from the glue and to assist the glue filling. The glue filling hole is used for allowing the heat conducting glue 4 to pass through, the size of the glue filling hole is not smaller than that of a single clearance position, and the glue filling hole can be opposite to the glue accommodating clearance 3 by adjusting the hole plugging plate.

By adopting the design, the auxiliary glue filling jig is used for filling glue, so that the glue filling difficulty of the glue containing gap 3 can be effectively reduced.

In the embodiments provided by the application, the types and structures of the jack plates are not unique.

Alternatively, in some embodiments, as shown in fig. 1, fig. 2 and fig. 3, the plugging plate may be a plugging aluminum plate 5, a plurality of flow holes 51 (i.e., glue filling holes) are formed in the plugging aluminum plate 5, and the flow holes 51 are used for allowing the heat-conducting glue 4 to pass through. The radiating block 2 is randomly installed in the through hole 11, the circumferential installation angle of the radiating block 2 and the arrangement direction of the bulge 22 in the through hole 11 are not fixed, in order to improve the use effect of the plug hole aluminum sheet 5, the circulation holes 51 on the plug hole aluminum sheet 5 are tightly connected, so that the circulation holes 51 can cover as many glue containing gaps 3 as possible, and in order to ensure the use effect and the reliability of the guide hole aluminum sheet, the distance between the adjacent circulation holes 51 is 0.1-0.15 mm. The thickness of the aluminum plug hole 5 can be designed to be 0.19mm-0.2mm.

It should be noted that, a circulation hole 51 may be made in the hole plugging aluminum sheet 5 by using a numerical control drilling machine, and after drilling, the hole plugging aluminum sheet 5 needs to be polished to be flat to remove the burr of the drilled hole.

Alternatively, in some embodiments, as shown in fig. 1, fig. 2 and fig. 4, the plugging plate may be a plugging screen 6, that is, a screen, and the plugging screen 6 is provided with a window 61 (corresponding to a glue filling hole), and the window 61 is used for allowing the thermal conductive glue 4 to pass through. The hole plugging screen plate 6 is manufactured by transferring a preset pattern to a silk screen or a steel wire mesh through photosensitive slurry, a position which does not need to be subjected to missing printing can be shielded during manufacturing, and a position which needs to be subjected to missing printing is formed into a window 61. In order to improve the glue filling effect, the window 61 of the hole plugging screen 6 can be directly designed into a ring shape, the inner diameter of the ring shape is not more than the size of the main body 21 of the heat dissipation block 2, and the outer diameter is not less than the aperture of the through hole 11.

It should be understood that fig. 3 and 4 are only used to illustrate the structures of the flow holes 51 on the hole plugging aluminum sheet 5 and the windows 61 on the hole plugging screen 6, and do not limit the actual structures of the hole plugging aluminum sheet 5 and the hole plugging screen 6.

In the embodiment provided by the present application, after step S11, the manufacturing method further includes: the through hole 11 is subjected to a hole metallization process such that the wall of the through hole 11 covers the first metal layer.

The heat dissipation block 2 may be a metal block such as a copper block or an aluminum block, or a ceramic block made of aluminum nitride or aluminum oxide. After the heat dissipation block 2 is installed in the through hole 11, the protrusion 22 abuts against the first metal layer on the hole wall of the through hole 11, and can be electrically connected with the hole wall.

Optionally, in some embodiments, the heat dissipation block 2 is a copper block, the first metal layer is a copper layer, and the hole metallization includes a copper deposition and an electroplating step.

By adopting the design, the conduction effect between circuit board layers can be improved by manufacturing the first metal layer.

In an embodiment provided by the present application, after step S12, the manufacturing method further includes: and performing hole metallization treatment on the through hole 11 and the heat dissipation block 2 to enable the first metal layer and the surface of the heat dissipation block 2 to be covered with the second metal layer.

Optionally, in some embodiments, the heat dissipation block 2 is a copper block, the first metal layer and the second metal layer are copper layers, and the hole metallization includes a copper deposition step and an electroplating step.

By adopting the above design, on one hand, the connection effect between the radiating block 2 and the substrate 1 can be improved, so that the radiating block 2 can be embedded in the substrate 1 more stably; on the other hand, the conduction effect between the heat dissipation block 2 and the substrate 1 can be improved, and the stability of the electrical connection between the heat dissipation block 2 and the substrate 1 can be improved.

In an embodiment provided by the present application, as shown in fig. 6, the manufacturing process includes: s21, providing a substrate 1, and drilling a through hole 11 on the substrate 1; s22, performing hole metallization treatment on the through hole 11 to enable the hole wall of the through hole 11 to cover the first metal layer; s23, installing the heat dissipation block 2 into the through hole 11; s24, performing hole metallization treatment on the through hole 11 and the heat dissipation block 2 to enable the first metal layer and the surface of the heat dissipation block 2 to cover the second metal layer; s25, manufacturing a protective film on the pad surface 24, and enabling the protective film to cover the hole of the through hole 11 on the side where the pad surface 24 is located; s26, providing a plugged plate and covering the plugged plate on the printing surface 23, wherein the plugged plate is provided with a glue filling hole which is opposite to the glue containing gap 3; s27, filling heat-conducting glue 4 into the glue containing gap 3; s28, removing the protective film; s29, baking and curing the heat-conducting glue 4 in the glue accommodating gap 3 with the printing surface 23 facing downwards; s210, coating the printing surface 23 of the heat dissipation block 2 with heat conduction glue 4.

The manufacturing process of the printed circuit board 100 can be simplified as follows: the method comprises the steps of a former process, a protective film pasting process, a heat conducting glue filling process 4 in the glue containing gap 3, a primary baking curing process, a secondary baking curing process and a later process, wherein the heat conducting glue 4 is coated on the printing surface 23.

Wherein, the former process can be one or more of the following processing technologies: cutting, inner layer pattern transfer, inner layer AOI, browning, plate stacking, pressing, drilling, hole metallization, copper embedding, electroplating, outer layer circuit manufacturing, solder resistance, molding, electrical testing and the like. The post-processing steps can include surface treatment, final inspection, packaging and the like.

In some embodiments, the film is attached, the thermal conductive adhesive 4 is filled, and the thermal conductive adhesive 4 is manufactured after the solder mask process, and the steps after the solder mask and the thermal conductive adhesive are classified as post processes. In some embodiments, the film is attached, the thermal conductive adhesive 4 is filled, and the thermal conductive adhesive 4 is manufactured after molding and electrical testing, and the design can be specifically performed according to the actual situation, which is not limited herein.

In summary, the method for manufacturing the printed circuit board with the embedded heat dissipation block provided by the application solves the problem of uneven surfaces of related products by improving the glue filling and gluing process of the printed circuit board 100, and effectively improves the heat dissipation effect and reliability of the circuit board product.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. A printed circuit board with embedded heat dissipation block, comprising:

the substrate is provided with a through hole;

2. The printed circuit board of claim 1, wherein the heat slug is a metal slug or a ceramic slug.

3. A method for manufacturing a heat-slug-embedded printed circuit board for manufacturing the heat-slug-embedded printed circuit board of claim 1 or 2, comprising:

providing a substrate, and drilling a through hole on the substrate;

installing a heat dissipation block into the through hole;

filling heat-conducting glue into the glue accommodating gap;

4. The method of claim 3, wherein the filling of the thermal conductive paste into the paste receiving space comprises: and filling a first heat-conducting glue and a second heat-conducting glue into the glue accommodating gap in sequence, wherein the viscosity of the first heat-conducting glue is less than that of the second heat-conducting glue.

5. The method for manufacturing a printed circuit board with an embedded heat dissipation block according to claim 4, wherein the volume ratio of the first heat-conducting glue to the second heat-conducting glue is 1.

6. The method for manufacturing a heat spreader embedded printed circuit board according to any one of claims 3-5, wherein the method further comprises, before or after the thermal conductive paste is applied to the printed surface of the heat spreader: and enabling the printing surface to face downwards, and baking and curing the heat-conducting glue in the glue accommodating gap.

7. The method for manufacturing a printed circuit board with an embedded heat dissipation block according to any one of claims 3-5, wherein before filling the heat conductive paste in the paste accommodating gap, the method further comprises: and manufacturing a protective film on the bonding pad surface, so that the protective film covers the hole of the through hole on the side of the bonding pad surface.

8. The method for manufacturing a printed circuit board with an embedded heat dissipation block according to any one of claims 3-5, wherein before filling the heat conductive glue into the glue accommodating gap, the method further comprises: and providing a plugging hole plate and covering the plugging hole plate on the printing surface, wherein the plugging hole plate is provided with a glue filling hole, and the glue filling hole is opposite to the glue accommodating gap.

9. The method for fabricating a heat slug embedded printed circuit board according to any one of claims 3-5, wherein after drilling the through hole on the substrate, the method further comprises: and performing hole metallization treatment on the through hole to enable the hole wall of the through hole to cover the first metal layer.

10. The method of claim 9, wherein after the step of installing the heat slug into the through hole, the method further comprises: and performing hole metallization treatment on the through hole and the heat dissipation block to enable the surfaces of the first metal layer and the heat dissipation block to cover the second metal layer.