Circuit board structure with excellent heat dissipation
The circuit board structure addresses slow heat dissipation in conventional designs by utilizing a direct heat discharge method through an exposed heat dissipation metal block and metal thin film layer, enhancing heat conduction and enabling more layers without connectivity issues.
Patent Information
- Application Number
- JP2025001760U
- Authority / Receiving Office
- JP · JP
- Patent Type
- Utility models
- Current Assignee / Owner
- Priority Date
- 2024-07-09
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-28
- Estimated Expiration
- 2035-05-30
AI Technical Summary
Conventional circuit board heat dissipation structures face inefficiencies in heat discharge due to limited heat convection and conduction paths, particularly through dielectric and metal layers, leading to slow heat dissipation.
A circuit board structure with a connection circuit layer module and a heat dissipation circuit layer module, featuring a heat dissipation metal block with an exposed heat dissipation surface, connected via a metal thin film layer and adhesive, allowing direct heat discharge without indirect convection or conduction through additional layers.
The structure enables rapid and efficient heat dissipation by direct heat discharge through exposed surfaces, improving heat conduction efficiency and allowing for increased layer stacking without compromising connectivity.
Smart Images
Figure 0003252193000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a circuit board structure, and more particularly to a circuit board structure with excellent heat dissipation performance.
Background Art
[0002] In order to maintain the quality of electrical signals transmitted by a circuit and extend the service life of electronic components in the circuit, it is necessary to efficiently discharge the waste heat generated during the operation of the circuit board to reduce the temperature of the circuit board, thereby reducing the influence of thermal noise on electrical signals.
[0003] As shown in FIG. 3, the heat dissipation structure 100 of a conventional circuit board is composed of an upper circuit layer module 110, a middle circuit layer module 120, and a lower circuit layer module 130, and the middle circuit layer module 120 is laminated between the upper circuit layer module 110 and the lower circuit layer module 130.
[0004] The upper circuit layer module 110 includes a laminated upper metal layer 111 and at least one dielectric layer 112, and the surface 113 of the upper metal layer 111 provided on the side opposite to the at least one dielectric layer 112 is used to receive the thermal energy generated by a heat source. For example, in the heat dissipation structure 100 of a conventional circuit board, the surface 113 where the electronic component 140 is disposed plays a role of receiving the waste heat generated by the energization of the electronic component 140.
[0005] The middle circuit layer module 120 includes a laminated upper-middle metal layer 121, a middle layer unit 122, and a lower-middle metal layer 123. The middle layer unit 122 is laminated between the upper-middle metal layer 121 and the lower-middle metal layer 123, and the surface of the upper-middle metal layer 121 provided on the side opposite to the middle layer unit 122 is connected to the at least one dielectric layer 112 in the upper circuit layer module 110.
[0006] The lower circuit layer module 130 includes at least one stacked dielectric layer 131 and a lower metal layer 132, and the surface provided on the side of the at least one dielectric layer 131 opposite to the lower metal layer 132 is connected to the middle lower metal layer 123 in the middle circuit layer module 120.
[0007] In the heat dissipation structure 100 of the conventional circuit board, in order to appropriately maintain the operating temperature of the electronic component 140 installed on the surface 113, a heat dissipation metal block 150 is installed in the middle layer unit 122 in the middle circuit layer module 120. Specifically, this heat dissipation metal block 150 is crimped between the upper middle metal layer 121 and the middle lower metal layer 123 in the middle circuit layer module 120 by a compression molding method during manufacturing. In addition, at least one heat dissipation hole is provided in the heat dissipation structure 100 of the conventional circuit board. For example, an upper heat dissipation hole 161, a middle heat dissipation hole 162, a lower heat dissipation hole 163, and a through heat dissipation hole 164 are installed.
[0008] The upper heat dissipation hole 161 penetrates the stacked upper metal layer 111 and at least one dielectric layer 112 in the upper circuit layer module 110, and communicates with the upper middle metal layer 121 in the upper circuit layer module 110, at least one dielectric layer 112, and the upper middle metal layer 121.
[0009] The middle heat dissipation hole 162 penetrates the stacked upper middle metal layer 121, the middle layer unit 122, and the middle lower metal layer 123 in the middle circuit layer module 120, and communicates with at least one dielectric layer 112, the upper middle metal layer 121, the middle layer unit 122, the middle lower metal layer 123, and at least one dielectric layer 131. One side surface of the heat dissipation metal block 150 is exposed in the middle heat dissipation hole 162.
[0010] The lower heat dissipation hole 163 penetrates the stacked at least one dielectric layer 131 and the lower metal layer 132 in the lower circuit layer module 130, and communicates with the middle lower metal layer 123, at least one dielectric layer 131, and the lower metal layer 132 in the middle circuit layer module 120.
[0011] The through heat dissipation holes 164 penetrate through the stacked upper circuit layer module 110, middle circuit layer module 120, and lower circuit layer module 130, communicate with those modules, and the other side surface of the heat dissipation metal block 150 is exposed within the through heat dissipation holes 164.
[0012] With the above configuration, in the heat dissipation structure 100 of the conventional circuit board, the heat from the electronic component 140 is conducted to the heat dissipation metal block 150, and further, the heat of the heat dissipation metal block 150 can be conducted to the middle heat dissipation holes 162 and through heat dissipation holes 164 via the middle upper metal layer 121. The middle heat dissipation holes 162 further conduct the heat to the middle lower metal layer 123.
Summary of the Invention
Problems to be Solved by the Invention
[0013] However, the middle lower metal layer 123 collects the heat directly or indirectly conducted from the heat dissipation metal block 150, but still discharges the heat outside the lower metal layer 132 through limited paths. Also, the middle lower metal layer 123 can discharge the heat outside the lower metal layer 132 through the lower heat dissipation holes 163 and through heat dissipation holes 164. However, since the degree of heat convection of air between the lower heat dissipation holes 163 and through heat dissipation holes 164 is limited, the heat discharge is slow in this method. Further, the middle lower metal layer 123 can also conduct the heat to at least one dielectric layer 131 first in the heat conduction method and then conduct the heat to the lower metal layer 132 through this dielectric layer 131. However, the heat conduction speed of the at least one dielectric layer 131 which is a dielectric material is slow, and the lower metal layer 132 needs to discharge the heat in the heat convection method. Thus, there is room for improvement in the heat discharge method of the conventional circuit board heat dissipation structure 100.
[0014] The present invention proposes a circuit board structure with excellent heat dissipation performance that can efficiently discharge the waste heat generated from the heat source.
Means for Solving the Problems
[0015] The circuit board structure with excellent heat dissipation performance of the present invention is A connection circuit layer module having a stacked connection metal layer and at least one dielectric layer, wherein the connection metal layer has a connection surface provided on a side opposite to the at least one dielectric layer, A heat dissipation circuit layer module having a stacked upper heat dissipation metal layer and a middle heat dissipation layer unit, The upper heat dissipation metal layer has a surface provided on a side opposite to the middle heat dissipation layer unit, and the surface is connected to the at least one dielectric layer in the connection circuit layer module, The middle heat dissipation layer unit has a heat dissipation metal block having a heat dissipation surface provided on a side opposite to the upper heat dissipation metal layer, and the heat dissipation surface is exposed from the heat dissipation circuit layer module.
Advantages of the Invention
[0016] Since the heat dissipation surface of the heat dissipation metal block of the present invention is directly exposed from the heat dissipation circuit layer module, the heat received by the heat dissipation metal block can be directly discharged, so there is no need to discharge the heat received indirectly through other structures, and it will not affect the heat dissipation speed. Therefore, compared with the heat dissipation structure of the conventional circuit board, the circuit board structure with excellent heat dissipation of the present invention can discharge heat more quickly without discharging the heat of the heat dissipation metal block indirectly through heat convection by heat dissipation holes or heat conduction by at least one dielectric layer or metal layer.
Brief Description of the Drawings
[0017]
Figure 1
Figure 2
Figure 3
Modes for Carrying Out the Invention
[0018] As shown in FIG. 1, the circuit board structure 1 with excellent heat dissipation according to the present invention is for assisting in heat dissipation of the electronic component 2, and the electronic component 2 applied to the circuit board structure 1 of the present invention is a heat source that easily generates thermal energy during operation.
[0019] In one embodiment of the present invention, the electronic component 2 is a light-emitting element, for example, a set of light-emitting diode (LED) headlights. This LED headlight is directly or indirectly installed on the circuit board structure 1 with excellent heat dissipation according to the present invention. Note that what is installed on the circuit board structure 1 with excellent heat dissipation of the present invention will be regarded as a heat source that requires heat dissipation.
[0020] FIG. 2 is a cross-sectional schematic diagram of the marked portion B along the cross-sectional line A of the circuit board structure 1 with excellent heat dissipation. In this embodiment, the circuit board structure 1 with excellent heat dissipation includes a stacked connection circuit layer module 10 and a heat dissipation circuit layer module 20.
[0021] The connection circuit layer module 10 has a stacked connection metal layer 11 and at least one dielectric layer 12. The connection surface 13 provided on the side of the connection metal layer 11 opposite to the at least one dielectric layer 12 is used to receive the heat generated by the electronic component 2.
[0022] The heat dissipation circuit layer module 20 has a stacked upper heat dissipation metal layer 21 and a middle heat dissipation layer unit 22. The surface 23 provided on the side of the upper heat dissipation metal layer 21 opposite to the middle heat dissipation layer unit 22 is connected to at least one dielectric layer 12 of the connection circuit layer module 10. Also, the middle heat dissipation layer unit 22 includes a plurality of stacked circuit board layers 24 and a heat dissipation metal block 25.
[0023] The heat-dissipating metal block 25 has a facing heat-receiving surface 251 and a heat-dissipating surface 252, and has at least one side wall surface 253 between the heat-receiving surface 251 and the heat-dissipating surface 252. The heat-receiving surface 251 of the heat-dissipating metal block 25 is arranged facing the upper heat-dissipating metal layer 21, and at least one side wall surface 253 of the heat-dissipating metal block 25 is surrounded by the stacked circuit board layers 24. Further, the heat-dissipating surface 252 provided on the side of the heat-dissipating metal block 25 opposite to the upper heat-dissipating metal layer 21 is exposed from the heat-dissipating circuit layer module 20. In the example shown in FIG. 2, these circuit board layers 24 are composed of a plurality of dielectric layers and metal layers stacked alternately, and in the circuit board layer 24 shown in FIG. 2, the portion drawn with diagonal lines is a metal layer, and the blank portion not drawn with diagonal lines indicates a dielectric layer.
[0024] Thereby, the heat-dissipating surface 252 exposed outside the heat-dissipating circuit layer module 20 can most efficiently discharge the heat from the heat-dissipating metal block 25 in the heat-dissipating circuit layer module 20. Therefore, in the present invention, it is not necessary to discharge the heat indirectly received through other structures, so it does not affect the heat discharge speed. Further, compared with the heat-dissipating structure 100 of the conventional circuit board shown in FIG. 3, the circuit board structure 1 with excellent heat dissipation of the present invention can discharge heat more quickly without discharging the heat of the heat-dissipating metal block 150 by heat convection of the lower heat-dissipating holes 163 and the through heat-dissipating holes 164 and multilayer heat conduction by the middle and lower metal layer 123, at least one dielectric layer 131 and the lower metal layer 132 as in the heat-dissipating structure 100 of the conventional circuit board.
[0025] Specifically, the circuit board layer 24 in this embodiment has holes 28 formed by etching, and the bottom surface 29 of the holes connected to the upper heat-dissipating metal layer is formed in these holes 28. Further, this circuit board structure 1 with excellent heat dissipation includes at least one first heat-dissipating hole 31, at least one second heat-dissipating hole 32, and at least one third heat-dissipating hole 33.
[0026] At least one first heat dissipation hole 31 penetrates through the connection metal layer 11 and at least one dielectric layer 12 in the connection circuit layer module 10. At least one second heat dissipation hole 32 penetrates through the upper heat dissipation metal layer 21 in the heat dissipation circuit layer module 20 and the circuit board layer 24 in the middle heat dissipation layer unit 22. At least one third heat dissipation hole 33 penetrates through the connection metal layer 11 and at least one dielectric layer 12 in the connection circuit layer module 10, and also penetrates through the upper heat dissipation metal layer 21 and the circuit board layer 24 in the heat dissipation circuit layer module 20. Therefore, at least one second heat dissipation hole 32 and at least one third heat dissipation hole 33 penetrate through the heat dissipation circuit layer module 20.
[0027] The hole 28 in the present invention communicates with at least one second heat dissipation hole 32 and at least one third heat dissipation hole 33 in the heat dissipation circuit layer module 20, and the heat dissipation metal block 25 is disposed in this hole 28. In order to more efficiently release heat to the outside of the heat dissipation circuit layer module 20 by the heat dissipation metal block 25 and simplify the process of installing the heat dissipation metal block 25 in the hole 28, in the present invention, the compression molding method is not used in the manufacturing process, and the method of fixing the heat dissipation metal block 25 in the hole 28 is adopted.
[0028] That is, in the heat dissipation structure 100 of the conventional circuit board shown in FIG. 3, the heat dissipation metal block 150 is crimped between the upper-middle metal layer 121 and the lower-middle metal layer 123 in the middle circuit layer module 120 by the compression molding method. However, in the present invention, since the lower-middle metal layer 123 that hinders heat dissipation is not provided, the crimping method is not adopted, and the method of fixing the heat dissipation metal block 25 in the hole 28 is adopted.
[0029] In the present invention, first, a metal thin film layer 26 is plated inside the hole 28, then a heat dissipation adhesive 27 is applied to the bottom surface 29 of the aforementioned hole, and finally, the heat dissipation metal block 25 is fixed in the hole 28 by utilizing the adhesiveness of the heat dissipation adhesive 27. This method has the following advantages.
[0030] (1) In the method of fixing the heat dissipation metal block 25 in the hole 28, since the heat dissipation metal block 25 is fixed to the hole 28 without being fixed by compression molding, the number of stacked layers of the circuit board layer 24 is not limited. That is, in the conventional technology, the number of stacked layers of the circuit board layer 24 is limited by compression molding. If the number of stacked layers is too large, good connection between each layer cannot be ensured. In contrast, the circuit board layer 24 of the present invention is stacked one by one by a semiconductor manufacturing process, so good connection between layers can be ensured. As a result, the number of layers of the circuit board layer 24 that can be stacked can be increased.
[0031] (2) In the method of fixing the heat dissipation metal block 25 with the heat dissipation adhesive 27, since the heat generated from the upper heat dissipation metal layer 21 can be conducted to the heat dissipation metal block 25 in a more dense heat conduction manner without gaps, the heat dissipation efficiency of the connection circuit layer module 10 and the electronic component 2 by the heat dissipation metal block 25 can be improved.
[0032] (3) The inner walls of at least one second heat dissipation hole 32 and the inner walls of at least one third heat dissipation hole 33 communicate with the hole 28, and a metal thin film layer 26 is plated on the hole 28. Moreover, this metal thin film layer 26 contacts at least one side wall surface 253 of the heat dissipation metal block 25. With such a configuration, the heat of the metal thin film layer 26 can be efficiently conducted by the inner walls of at least one second heat dissipation hole 32 and the inner walls of at least one third heat dissipation hole 33. Also, at least one second heat dissipation hole 32 and at least one third heat dissipation hole 33 do not need to discharge the heat of the heat dissipation metal block 25 installed between them by the heat convection method. By using the heat conduction method, the heat can be released from the heat dissipation circuit layer module 20 faster and more efficiently. That is, at least one second heat dissipation hole 32 and at least one third heat dissipation hole filled with the metal thin film layer 26 function as a rapid heat conduction path.
[0033] The heat-dissipating metal block 25 and the metal thin film layer 26 are preferably made of the same metal material. For example, in this embodiment, the heat-dissipating metal block 25 is a copper-made metal block, and the metal thin film layer 25 is a copper thin film layer. In this way, the heat-dissipating metal block 25 and the metal thin film layer 26 with the same thermal conductivity can efficiently release heat from the heat-dissipating metal block 25 to the outside of the heat-dissipating circuit layer module 20 through heat conduction. Incidentally, in one embodiment, the heat-dissipating adhesive 27 may be a graphite adhesive, and in other embodiments, the heat-dissipating adhesive 27 may contain the same metal material as the heat-dissipating metal block 25. For example, the heat-dissipating metal block 25 is a silver-made metal block, the metal thin film layer 26 is a silver thin film layer, and the heat-dissipating adhesive 27 is a silver adhesive. On the other hand, in this embodiment, the metal layer portions in these circuit board layers 24 are all grounded.
Description of Reference Numerals
[0034] 1 Circuit board structure with excellent heat dissipation 2 Electronic component 10 Connection circuit layer module 11 Connection metal layer 12 Dielectric layer 13 Connection surface 20 Heat-dissipating circuit layer module 21 Upper heat-dissipating metal layer 22 Middle heat-dissipating layer unit 23 Surface 24 Circuit board layer 25 Heat-dissipating metal block 26 Metal thin film layer 27 Heat-dissipating adhesive 28 Hole 29 Bottom surface of the hole 31 First heat-dissipating hole 32 Second heat-dissipating hole 33 Third heat-dissipating hole 100 Heat dissipation structure of the conventional circuit board 110 Upper circuit layer module 111 Upper metal layer 112 Dielectric layer 113 Surface 120 Middle circuit layer module 121 Middle upper metal layer 122 Middle layer unit 123 Middle and lower metal layer 130 Lower circuit layer module 131 Dielectric layer 132 Lower metal layer 140 Electronic component 150 Heat dissipation metal block 161 Upper heat dissipation hole 162 Middle heat dissipation hole 163 Lower heat dissipation hole 164 Through heat dissipation hole 251 Heat receiving surface 252 Heat dissipation surface 253 Side wall surface A section line Part marked with B
Claims
1. A circuit board structure with excellent heat dissipation performance, having a stacked connection metal layer and at least one dielectric layer, wherein the connection circuit layer module has a connection surface provided on a side opposite to the at least one dielectric layer, and a heat dissipation circuit layer module having a stacked upper heat dissipation metal layer and a middle heat dissipation layer unit, wherein the upper heat dissipation metal layer has a surface provided on a side opposite to the middle heat dissipation layer unit, and the surface is connected to the at least one dielectric layer in the connection circuit layer module, the middle heat dissipation layer unit has a heat dissipation metal block having a heat dissipation surface provided on a side opposite to the upper heat dissipation metal layer, and the heat dissipation surface is exposed from the heat dissipation circuit layer module, characterized in that it is a circuit board structure with excellent heat dissipation performance.
2. The middle heat dissipation layer unit includes a plurality of stacked circuit board layers, the plurality of circuit board layers have holes formed by etching, and the heat dissipation metal layer is installed in the holes, characterized in that it is the circuit board structure with excellent heat dissipation performance according to Claim 1.
3. At least one heat dissipation hole penetrating through the stacked upper heat dissipation metal layer and the plurality of circuit board layers is formed in the heat dissipation circuit layer module, the at least one heat dissipation hole communicates with the holes and the connection surface, each of the at least one heat dissipation holes has an inner wall, and a metal thin film layer is plated between the heat dissipation metal block and the inner wall of the at least one heat dissipation hole, characterized in that it is the circuit board structure with excellent heat dissipation performance according to Claim 2.
4. The heat dissipation metal block and the metal thin film layer are composed of the same metal material, characterized in that it is the circuit board structure with excellent heat dissipation performance according to Claim 3.
5. The heat dissipation metal block is a copper-made metal block, and the metal thin film layer is a copper thin film layer, characterized in that it is the circuit board structure with excellent heat dissipation performance according to Claim 4.
6. The at least one heat dissipation hole communicating with the holes is a plurality of the heat dissipation holes, and the heat dissipation metal block is installed between those heat dissipation holes, characterized in that it is the circuit board structure with excellent heat dissipation performance according to Claim 3.
7. A bottom surface of a hole connected to the upper heat dissipation metal layer is formed in the hole in the middle heat dissipation layer unit, and a heat dissipation adhesive is filled between the bottom surface of the hole and the heat dissipation metal block. The circuit board structure excellent in heat dissipation according to claim 2, characterized by the above.
8. The heat dissipation adhesive contains a plurality of metal particles, and the metal particles and the heat dissipation metal block are made of the same metal. The circuit board structure excellent in heat dissipation according to claim 7, characterized by the above.
9. At least one upper heat dissipation hole penetrating the laminated connection metal layer and the at least one dielectric layer is formed in the connection circuit layer module. The circuit board structure excellent in heat dissipation according to claim 1, characterized by the above.