Multi-layer circuit board heat dissipation structure

Abstract

The utility model discloses a multilayer circuit board heat radiation structure, an inner core plate comprises a first copper foil, a first insulation heat conduction layer and a second copper foil, the first insulation heat conduction layer is provided with a mounting hole, a heat radiation copper block is embedded in the mounting hole, the first copper foil is pressed on the upper surface of the first insulation heat conduction layer and is attached to the heat radiation copper block, and the second copper foil is pressed on the upper surface of the second insulation heat conduction layer. The second copper foil is pressed on the lower surface of the first insulation heat conduction layer and attached to the heat dissipation copper block, and heat received by the third copper foil located on the surface layer can be transmitted to the heat dissipation copper block through the first electroplated layer and then transmitted to the fourth copper foil located on the bottommost layer through the second electroplated layer to be dissipated out. Therefore, the heat dissipation effect of the multilayer circuit board can be greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of circuit board technology, and in particular to a heat dissipation structure for multilayer circuit boards. Background Technology

[0002] Circuit boards (PCBs) are a crucial component of electronic devices, housing various electronic components and responsible for transmitting electrical signals and power. Since electronic components generate heat during operation, a heat dissipation structure is essential for ensuring the proper functioning of the PCB. Existing heat dissipation structures involve setting multiple heat dissipation vias on the PCB. However, increasing the number of vias leads to a larger PCB size, and with the increasing functionality of modern electronic products and the ever-increasing wiring density, it is difficult to find a dedicated space for these vias. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a multi-layer circuit board heat dissipation structure, which can achieve better heat dissipation without affecting the layout of the circuit on the circuit board surface.

[0004] According to an embodiment of the present invention, a multilayer circuit board heat dissipation structure includes: an inner core board comprising a first copper foil, a first insulating and heat-conducting layer, and a second copper foil; the first insulating and heat-conducting layer having a mounting hole, a heat-dissipating copper block being embedded in the mounting hole; the first copper foil being pressed onto the upper surface of the first insulating and heat-conducting layer and in contact with the heat-dissipating copper block; the second copper foil being pressed onto the lower surface of the first insulating and heat-conducting layer and in contact with the heat-dissipating copper block; a third copper foil being connected to the upper surface of the first copper foil via a second insulating and heat-conducting layer; the second insulating and heat-conducting layer having a first groove extending downward to the first copper foil; a first electroplated layer being disposed in the first groove; the first electroplated layer being connected between the first copper foil and the third copper foil; and a fourth copper foil being connected to the lower surface of the second copper foil via a third insulating and heat-conducting layer; the third insulating and heat-conducting layer having a second groove extending upward to the second copper foil; a second electroplated layer being disposed in the second groove; the second electroplated layer being connected between the second copper foil and the fourth copper foil.

[0005] The multilayer circuit board heat dissipation structure according to the embodiments of this utility model has at least the following beneficial effects:

[0006] In the multilayer circuit board heat dissipation structure of this utility model embodiment, the multilayer circuit board includes a third copper foil, a second insulating thermally conductive layer, a first copper foil, a second copper foil, a third insulating thermally conductive layer, and a fourth copper foil arranged sequentially from top to bottom. By opening mounting holes in the first insulating thermally conductive layer and pressing a heat dissipation copper block into the mounting holes, the first and second copper foils can be pressed together on the upper and lower surfaces of the first insulating thermally conductive layer during subsequent pressing processes, and both can contact the heat dissipation copper block. Thus, during use, the electronic components are mounted on the outermost third copper foil, and the heat generated by the electronic components can be transferred to the third copper foil, then to the heat dissipation copper block through the first electroplating layer, and then to the bottom fourth copper foil through the second electroplating layer to dissipate the heat. This greatly improves the heat dissipation effect of the multilayer circuit board, and this structure does not require opening numerous heat dissipation through-holes, therefore it does not affect the layout of the circuitry on the circuit board surface.

[0007] According to some embodiments of the present invention, the first groove is formed on the upper surface of the third copper foil and extends downward to the first copper foil, and the first electroplated layer extends upward from the first copper foil to be flush with the upper surface of the third copper foil; the second groove is formed on the upper surface of the fourth copper foil and extends upward to the second copper foil, and the second electroplated layer extends downward from the second copper foil to be flush with the lower surface of the fourth copper foil.

[0008] According to some embodiments of the present invention, the first groove is located above the heat dissipation copper block, and the second groove is located below the heat dissipation copper block.

[0009] According to some embodiments of the present invention, a metal substrate is also included, which is connected to the lower surface of the fourth copper foil through a fourth insulating and thermally conductive layer.

[0010] According to some embodiments of the present invention, the metal substrate is a copper substrate.

[0011] According to some embodiments of the present invention, the thickness of the metal substrate is 1 mm, the first copper foil and the second copper foil are 1 oz copper foil, and the third copper foil and the fourth copper foil are Hoz copper foil.

[0012] According to some embodiments of the present invention, the first insulating thermally conductive layer, the second insulating thermally conductive layer, the third insulating thermally conductive layer, and the fourth insulating thermally conductive layer are all high thermal conductivity PP layers.

[0013] According to some embodiments of the present invention, the thickness of the first insulating thermally conductive layer is 0.2 mm, and the thicknesses of the second, third, and fourth insulating thermally conductive layers are all 0.1 mm.

[0014] According to some embodiments of the present invention, the inner core plate and / or the second insulating and heat-conducting layer and / or the third insulating and heat-conducting layer are provided with heat dissipation buried holes, which are located between the third copper foil and the fourth copper foil.

[0015] According to some embodiments of the present invention, the heat dissipation buried hole extends downward from the second insulating and heat-conducting layer to the third insulating and heat-conducting layer. The inner wall of the heat dissipation buried hole is provided with a copper layer. The copper layer extends upward to the upper end of the heat dissipation buried hole and connects with the lower surface of the third copper foil. The copper layer also extends downward to the lower end of the heat dissipation buried hole and connects with the upper surface of the fourth copper foil.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the heat dissipation structure of a multilayer circuit board according to an embodiment of the present invention.

[0019] Figure label:

[0020] The components include an inner core board 100, a first copper foil 110, a first insulating and heat-conducting layer 120, a mounting hole 121, a heat-dissipating copper block 122, a second copper foil 130, a second insulating and heat-conducting layer 140, a first groove 141, a first electroplated layer 142, a third copper foil 150, a third insulating and heat-conducting layer 160, a second groove 161, a second electroplated layer 162, a fourth copper foil 170, a fourth insulating and heat-conducting layer 180, and a metal substrate 190. Detailed Implementation

[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0022] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0025] Reference Figure 1 This utility model provides a multilayer circuit board heat dissipation structure, which includes an inner core board 100, a third copper foil 150, and a fourth copper foil 170. The inner core board 100 includes a first copper foil 110, a first insulating and heat-conducting layer 120, and a second copper foil 130. The first insulating and heat-conducting layer 120 has a mounting hole 121, and a heat dissipation copper block 122 is embedded in the mounting hole 121. The first copper foil 110 is pressed onto the upper surface of the first insulating and heat-conducting layer 120 and is in contact with the heat dissipation copper block 122. The second copper foil 130 is pressed onto the lower surface of the first insulating and heat-conducting layer 120 and is in contact with the heat dissipation copper block 122. The third copper foil 150 is connected to the upper surface of the first copper foil 110 via the second insulating and heat-conducting layer 140. The second insulating and heat-conducting layer 140 has a first groove 141 extending downward to the first copper foil 110. A first electroplated layer 142 is disposed in the first groove 141, and the first electroplated layer 142 connects the first copper foil 110 and the third copper foil 150. The fourth copper foil 170 is connected to the lower surface of the second copper foil 130 via the third insulating and heat-conducting layer 160. The third insulating and heat-conducting layer 160 has a second groove 161 extending upward to the second copper foil 130. A second electroplated layer 162 is disposed in the second groove 161, and the second electroplated layer 162 connects the second copper foil 130 and the fourth copper foil 170.

[0026] In the multilayer circuit board heat dissipation structure of this utility model embodiment, the multilayer circuit board includes a third copper foil 150, a second insulating and thermally conductive layer 140, a first copper foil 110, a first insulating and thermally conductive layer 120, a second copper foil 130, a third insulating and thermally conductive layer 160, and a fourth copper foil 170 arranged sequentially from top to bottom. By opening mounting holes 121 in the first insulating and thermally conductive layer 120 and pressing a heat dissipation copper block 122 into the mounting holes 121, the first copper foil 110 and... The second copper foil 130 is pressed onto the upper and lower surfaces of the first insulating and heat-conducting layer 120 and is in contact with the heat-dissipating copper block 122. Furthermore, by forming a first groove 141 on the second insulating and heat-conducting layer 140 and electroplating a first electroplated layer 142 within the first groove 141, the first electroplated layer 142 connects the first copper foil 110 and the third copper foil 150. Similarly, by forming a second groove 161 on the third insulating and heat-conducting layer 160 and electroplating a second electroplated layer 162 within the second groove 161, the second... The electroplated layer 162 connects the second copper foil 130 and the fourth copper foil 170. Thus, during use, the electronic components are mounted on the outermost third copper foil 150. The heat generated by these components can be transferred to the third copper foil 150, then through the first electroplated layer 142 to the heat sink 122, and finally through the second electroplated layer 162 to the bottom fourth copper foil 170 for dissipation. This significantly improves the heat dissipation of the multilayer circuit board, and this structure eliminates the need for additional openings. The numerous heat dissipation through holes do not affect the layout of the circuit board surface. In addition, this structure does not require the processing of blind slots on the first copper foil 110 or the second copper foil 130 of the inner core board 100. The mounting holes 121 can be directly opened on the first insulating and heat-conducting layer 120, and the heat dissipation copper block 122 can be embedded in the mounting holes 121. There is no need to electroplate copper filling into the mounting holes 121. The heat dissipation copper block 122 can be embedded in the inner core board 100 directly by performing the normal pressing process, which greatly reduces the manufacturing difficulty of the circuit board.

[0027] Furthermore, in the multilayer circuit board heat dissipation structure of this utility model embodiment, the arrangement of the first insulating thermally conductive layer 120, the second insulating thermally conductive layer 140, and the third insulating thermally conductive layer 160 can further improve the heat transfer efficiency, thereby further improving the heat dissipation effect of the multilayer circuit board. Moreover, during the heat transfer process, in addition to the heat being transferred downwards along the first insulating thermally conductive layer 120, the second insulating thermally conductive layer 140, and the third insulating thermally conductive layer 160 to the fourth copper foil 170, some heat can also be transferred horizontally outwards along the first insulating thermally conductive layer 120, the second insulating thermally conductive layer 140, and the third insulating thermally conductive layer 160, thereby greatly improving the heat dissipation effect.

[0028] In some embodiments, a first groove 141 is formed on the upper surface of the third copper foil 150 and extends downward to the first copper foil 110, and a first electroplated layer 142 extends upward from the first copper foil 110 to be flush with the upper surface of the third copper foil 150; a second groove 161 is formed on the upper surface of the fourth copper foil 170 and extends upward to the second copper foil 130, and a second electroplated layer 162 extends downward from the second copper foil 130 to be flush with the lower surface of the fourth copper foil 170.

[0029] By adopting the above structure, during processing, after the third copper foil 150, the second insulating and heat-conducting layer 140, the first copper foil 110, the first insulating and heat-conducting layer 120, the second copper foil 130, the third insulating and heat-conducting layer 160, and the fourth copper foil 170 are laminated, a first groove 141 extending downward from the third copper foil 150 to the first copper foil 110, and a second groove 161 extending upward from the fourth copper foil 170 to the second copper foil 130 are formed. Then, electroplating is used to form the first... Electroplating layer 142 and second electroplating layer 162 are arranged such that the first electroplating layer 142 is flush with the upper surface of the third copper foil 150, and the second electroplating layer 162 is flush with the lower surface of the fourth copper foil 170. Thus, the heat generated by the electronic components can be transferred outward in sequence through the third copper foil 150, the first electroplating layer 142, the first copper foil 110, the heat dissipation copper block 122, the second copper foil 130, the second electroplating layer 162 and the fourth copper foil 170. This process is convenient and has a good heat dissipation effect, and can ensure the flatness of the upper and lower surfaces of the multilayer circuit board.

[0030] Understandably, referring to Figure 1 In some embodiments, the first groove 141 can also be directly formed on the second insulating and heat-conducting layer 140. During processing, the second insulating and heat-conducting layer 140 is first pressed onto the upper surface of the first copper foil 110, and a first electroplated layer 142 is formed on the first copper foil 110 at the bottom of the first groove 141, so that the first electroplated layer 142 fills the first groove 141. Then, the third copper foil 150 is pressed onto the second insulating and heat-conducting layer 140 and presses against the first electroplated layer 142. In this way, the heat on the third copper foil 150 can also be transferred downward to the first copper foil 110. Similarly, the second groove 161 can also be directly formed on the third insulating and heat-conducting layer 160. During processing, the third insulating and heat-conducting layer 160 is first pressed onto the lower surface of the second copper foil 130, and a second electroplated layer 162 is formed on the second copper foil 130 in the second groove 161, so that the second electroplated layer 162 fills the second groove 161. Then, the fourth copper foil 170 is pressed onto the third insulating and heat-conducting layer 160 and abuts against the second electroplated layer 162. In this way, the heat on the second copper foil 130 can also be transferred downward to the fourth copper foil 170.

[0031] It is understandable that both the first electroplating layer 142 and the second electroplating layer 162 are copper plating layers.

[0032] Reference Figure 1 In some embodiments, the first groove 141 is located above the heat dissipation copper block 122, and the second groove 161 is located below the heat dissipation copper block 122.

[0033] By adopting the above structure, placing the first groove 141 above the heat dissipation copper block 122 shortens the distance between the first electroplated layer 142 and the heat dissipation copper block 122. This accelerates the time it takes for heat to transfer downwards from the first electroplated layer 142 to the heat dissipation copper block 122, greatly improving heat transfer efficiency and heat dissipation effect. Similarly, by placing the second groove 161 below the heat dissipation copper block 122, the distance between the second electroplated layer 162 and the heat dissipation copper block 122 is shortened. This accelerates the time it takes for heat to transfer downwards from the heat dissipation copper block 122 to the second electroplated layer 162, further greatly improving heat transfer efficiency and heat dissipation effect.

[0034] It is understandable that, in addition to being positioned above the heat dissipation copper block 122, the first groove 141 can also be horizontally offset from the heat dissipation copper block 122. In this case, the heat from the first electroplated layer 142 can first be transferred downwards to the first copper foil 110, and then horizontally along the first copper foil 110 to the heat dissipation copper block 122. Similarly, in addition to being positioned below the heat dissipation copper block 122, the second groove 161 can also be horizontally offset from the heat dissipation copper block 122. In this case, the heat from the heat dissipation copper block 122 can first be transferred downwards to the second copper foil 130, and then horizontally along the second copper foil 130 to the second electroplated layer 162.

[0035] It is possible that, in some embodiments, the number of the first groove 141 and the second groove 161 can be set to one, two, three or more, and the present invention does not specifically limit this.

[0036] Reference Figure 1 In some embodiments, the multilayer circuit board heat dissipation structure further includes a metal substrate 190, which is connected to the lower surface of the fourth copper foil 170 through a fourth insulating thermally conductive layer 180.

[0037] In the above structure, the heat generated by the electronic components is transferred to the third copper foil 150, and then sequentially downwards along the first electroplated layer 142, the first copper foil 110, the heat dissipation copper block 122, the second copper foil 130, the second electroplated layer 162, and the fourth copper foil 170, finally reaching the metal substrate 190 and being transferred outwards through the metal substrate 190. The metal substrate 190 has excellent heat dissipation performance, effectively conducting heat to the outside, thereby further improving the heat dissipation effect of the multilayer circuit board. In addition, the metal substrate 190 can also effectively alleviate the thermal expansion and contraction problem of the multilayer circuit board, improving the durability and reliability of the multilayer circuit board.

[0038] In some embodiments, the metal substrate 190 is a copper substrate. The copper substrate has excellent thermal conductivity and thermal stability, and can quickly conduct heat outward, thereby effectively reducing the temperature of the circuit board. Furthermore, since the copper substrate is pressed onto the lower surface of the fourth copper foil 170 through the fourth insulating thermally conductive layer 180, the large-area copper substrate can conduct heat to the outside of the circuit board in a timely manner, reducing the risk of local overheating.

[0039] It is understood that the metal substrate 190 can also be a copper substrate, an aluminum substrate, or a substrate of other materials, and this utility model does not make any specific limitation in this regard.

[0040] In some embodiments, the metal substrate 190 has a thickness of 1 mm, the first copper foil 110 and the second copper foil 130 are 1 oz copper foils, and the third copper foil 150 and the fourth copper foil 170 are 1 oz copper foils, thereby effectively improving the electrical performance of the multilayer circuit board. By setting the thickness of the metal substrate 190 to 1 mm, the thicker metal substrate 190 can better absorb the heat transferred downward from the fourth copper foil 170 and can quickly transfer the heat away, thereby further improving the heat dissipation effect of the multilayer circuit board.

[0041] In some embodiments, the first insulating thermally conductive layer 120, the second insulating thermally conductive layer 140, the third insulating thermally conductive layer 160, and the fourth insulating thermally conductive layer 180 are all high thermal conductivity PP layers. This can greatly improve the thermal conductivity of the first insulating thermally conductive layer 120, the second insulating thermally conductive layer 140, the third insulating thermally conductive layer 160, and the fourth insulating thermally conductive layer 180, thereby improving the heat dissipation efficiency of the multilayer circuit board.

[0042] In some embodiments, the thickness of the first insulating thermally conductive layer 120 is 0.2 mm, and the thicknesses of the second insulating thermally conductive layer 140, the third insulating thermally conductive layer 160, and the fourth insulating thermally conductive layer 180 are all 0.1 mm. In this structure, the thickness of the first insulating thermally conductive layer 120 is greater than the thicknesses of the second insulating thermally conductive layer 140, the third insulating thermally conductive layer 160, and the fourth insulating thermally conductive layer 180, thereby increasing the thickness of the heat dissipation copper block 122 embedded in the mounting hole 121 of the first insulating thermally conductive layer 120, which is beneficial to further improve the heat dissipation performance of the multilayer circuit board. In addition, setting the thickness of the second insulating thermally conductive layer 140, the third insulating thermally conductive layer 160, and the fourth insulating thermally conductive layer 180 to 0.1 mm is beneficial to the rapid downward transfer of heat, thereby facilitating the improvement of heat transfer efficiency.

[0043] In some embodiments, the inner core plate 100 and / or the second insulating thermally conductive layer 140 and / or the third insulating thermally conductive layer 160 are provided with heat dissipation buried holes (not shown in the figure), which are located between the third copper foil 150 and the fourth copper foil 170.

[0044] In the above structure, the heat dissipation holes can also play a certain role in heat dissipation, which facilitates the transfer of heat downward to the fourth copper foil 170, thereby improving the heat dissipation effect of the multilayer circuit board without affecting the layout of the circuit on the surface of the multilayer circuit board.

[0045] In some embodiments, the heat dissipation buried hole extends downward from the second insulating thermal conductive layer 140 to the third insulating thermal conductive layer 160. The inner wall of the heat dissipation buried hole is provided with a copper layer, which extends upward to the upper end of the heat dissipation buried hole and connects to the lower surface of the third copper foil 150, and extends downward to the lower end of the heat dissipation buried hole and connects to the upper surface of the fourth copper foil 170.

[0046] In the above structure, the heat dissipation vias are sequentially inserted downwards through the second insulating thermally conductive layer 140 into the first copper foil 110, the first insulating thermally conductive layer 120, the second copper foil 130, and the third insulating thermally conductive layer 160. The upper and lower ends of the copper layer on the inner wall of the heat dissipation via are connected to the third copper foil 150 and the fourth copper foil 170, respectively. Therefore, not only do the heat dissipation vias provide heat dissipation, but the copper layer on the inner wall of the vias also transfers heat, greatly improving the heat dissipation performance of the multilayer circuit board. The copper layer on the inner wall of the heat dissipation vias can receive heat transferred downwards from the third copper foil 150, and also receive heat transferred horizontally from the second insulating thermally conductive layer 140, the first copper foil 110, the first insulating thermally conductive layer 120, the second copper foil 130, and the third insulating thermally conductive layer 160. Furthermore, the copper layer on the inner wall of the heat dissipation vias can transfer heat downwards to the fourth copper foil 170, allowing the heat to dissipate outwards, thus providing heat dissipation for the multilayer circuit board.

[0047] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A multilayer circuit board heat dissipation structure, characterized in that, include: The inner core plate (100) includes a first copper foil (110), a first insulating and heat-conducting layer (120), and a second copper foil (130). The first insulating and heat-conducting layer (120) has a mounting hole (121), and a heat-dissipating copper block (122) is embedded in the mounting hole (121). The first copper foil (110) is pressed onto the upper surface of the first insulating and heat-conducting layer (120) and is in contact with the heat-dissipating copper block (122). The second copper foil (130) is pressed onto the lower surface of the first insulating and heat-conducting layer (120) and is in contact with the heat-dissipating copper block (122). The third copper foil (150) is connected to the upper surface of the first copper foil (110) through the second insulating and heat-conducting layer (140). The second insulating and heat-conducting layer (140) has a first groove (141) extending downward to the first copper foil (110). A first electroplated layer (142) is provided in the first groove (141). The first electroplated layer (142) is connected between the first copper foil (110) and the third copper foil (150). The fourth copper foil (170) is connected to the lower surface of the second copper foil (130) through the third insulating and heat-conducting layer (160). The third insulating and heat-conducting layer (160) has a second groove (161) extending upward to the second copper foil (130). A second electroplated layer (162) is disposed in the second groove (161). The second electroplated layer (162) is connected between the second copper foil (130) and the fourth copper foil (170).

2. The multilayer circuit board heat dissipation structure according to claim 1, characterized in that, The first groove (141) is formed on the upper surface of the third copper foil (150) and extends downward to the first copper foil (110), and the first electroplated layer (142) extends upward from the first copper foil (110) to be flush with the upper surface of the third copper foil (150); The second groove (161) is formed on the upper surface of the fourth copper foil (170) and extends upward to the second copper foil (130). The second electroplated layer (162) extends downward from the second copper foil (130) to be flush with the lower surface of the fourth copper foil (170).

3. The multilayer circuit board heat dissipation structure according to claim 1 or 2, characterized in that, The first groove (141) is located above the heat dissipation copper block (122), and the second groove (161) is located below the heat dissipation copper block (122).

4. The multilayer circuit board heat dissipation structure according to claim 1, characterized in that, It also includes a metal substrate (190), which is connected to the lower surface of the fourth copper foil (170) via a fourth insulating and thermally conductive layer (180).

5. The multilayer circuit board heat dissipation structure according to claim 4, characterized in that, The metal substrate (190) is a copper substrate.

6. The multilayer circuit board heat dissipation structure according to claim 5, characterized in that, The metal substrate (190) has a thickness of 1 mm, the first copper foil (110) and the second copper foil (130) are 1 oz copper foils, and the third copper foil (150) and the fourth copper foil (170) are Hoz copper foils.

7. The multilayer circuit board heat dissipation structure according to claim 4, characterized in that, The first insulating thermally conductive layer (120), the second insulating thermally conductive layer (140), the third insulating thermally conductive layer (160) and the fourth insulating thermally conductive layer (180) are all high thermal conductivity PP layers.

8. The multilayer circuit board heat dissipation structure according to claim 7, characterized in that, The thickness of the first insulating thermally conductive layer (120) is 0.2 mm, and the thickness of the second insulating thermally conductive layer (140), the third insulating thermally conductive layer (160) and the fourth insulating thermally conductive layer (180) are all 0.1 mm.

9. The multilayer circuit board heat dissipation structure according to claim 1, characterized in that, The inner core plate (100) and / or the second insulating and heat-conducting layer (140) and / or the third insulating and heat-conducting layer (160) are provided with heat dissipation buried holes, which are located between the third copper foil (150) and the fourth copper foil (170).

10. The multilayer circuit board heat dissipation structure according to claim 9, characterized in that, The heat dissipation buried hole extends downward from the second insulating heat-conducting layer (140) to the third insulating heat-conducting layer (160). The inner wall of the heat dissipation buried hole is provided with a copper layer. The copper layer extends upward to the upper end of the heat dissipation buried hole and connects with the lower surface of the third copper foil (150). The copper layer extends downward to the lower end of the heat dissipation buried hole and connects with the upper surface of the fourth copper foil (170).

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