Aluminum-based circuit board manufacturing method and aluminum-based circuit board

Abstract

The present invention discloses an aluminum-based circuit board and a manufacturing method thereof, which comprises a circuit layer, an insulating heat-conducting layer, an aluminum substrate and conductive nails; the circuit layer is formed by mechanical processing or cutting; at least one surface of the aluminum substrate is processed to form a convex portion or a concave portion corresponding to the size and shape of the circuit layer; the circuit layer is arranged at the position of the concave portion or the convex portion; at least one through hole is also arranged on the aluminum substrate; the insulating heat-conducting layer covers the surface of the aluminum substrate and the inner wall of the through hole; wherein the conductive nail is installed in the through hole and is non-conductive with the through hole; at least one end of the conductive nail is located on the surface of the aluminum substrate, and the two ends of the conductive nail are respectively connected to the two circuit layers. The aluminum-based circuit board provided by the present invention overcomes the technical problem that it is not convenient to manufacture a multi-layer aluminum-based circuit board with multiple circuit layers in the prior art through the conductive nails, and at the same time, the thermal conductivity and heat dissipation efficiency of the multi-layer aluminum-based circuit board are also improved through the conductive nails.

Description

Technical Field

[0001] The invention relates to the field of circuit boards, and in particular to a method for manufacturing an aluminum-based circuit board and an aluminum-based circuit board. Background Art

[0002] Aluminum-based circuit boards refer to circuit boards that use aluminum as the substrate. Traditional circuit boards generally use resin substrates, such as FR4 materials. Due to the metal aluminum substrate, aluminum-based circuit boards can absorb the heat generated by the circuit layer through the substrate to the maximum extent, thereby improving the heat dissipation capacity, especially in areas that generate large amounts of heat, such as high-power power supplies and LED lighting. Because of this, the thickness of the circuit layer set on the aluminum substrate can be larger, generally around 3oz to 10oz, and can withstand higher currents, and is also suitable for use in high-frequency circuit fields. In addition, compared to FR4 substrates, the dimensional change rate of aluminum substrates when heated is smaller, about 0.4% or less, so that the circuit layer made thereon has better consistency, and can reduce the defects of the circuit layer caused by dimensional changes due to heat accumulation, such as breakage or deformation. Finally, aluminum substrates are also easy to open holes, install and fix.

[0003] like Figure 1 The existing aluminum-based circuit board A includes a circuit layer A1, an insulating heat-conducting layer A2 and an aluminum substrate A3; the process for making such an aluminum-based circuit board is as follows:

[0004] 1. Processing the aluminum substrate A3, such as plasma cleaning;

[0005] 2. Coating, screen printing, spraying or depositing an insulating thermal conductive layer A2 on the surface of the aluminum substrate A3, wherein the insulating thermal conductive layer A2 is a resin mixed with thermal conductive particles;

[0006] 3. Making the circuit layer A1, which is generally a copper-clad laminate, that is, an anti-corrosion layer is provided on the copper layer, and then the copper-clad laminate is etched after removing the anti-corrosion layer according to the required circuit to form the circuit layer A1;

[0007] 4. Fix the fabricated circuit layer A1 on the aluminum substrate A3 having the insulating heat-conducting layer A2 by means of resin glue;

[0008] 5. Screen printing, coating the surface with ink, exposing the circuit position or welding point that needs to be welded;

[0009] 6. Place the circuit layer A1 and the aluminum substrate A3 through SMT chip components A4.

[0010] After the above, the aluminum-based circuit board was produced. However, such structure and process have many technical problems:

[0011] 1. Since the aluminum substrate is made of aluminum, the most common aluminum-based circuit boards are single-sided or double-sided boards, and it is difficult to make multi-layer boards. A single-sided board means that the circuit layer and components are only on one surface of the aluminum substrate, and a double-sided board means that the circuit layer and components are on both surfaces of the aluminum substrate. When making multi-layer circuit boards, blind holes and semi-blind holes need to be set. Blind holes and semi-blind holes refer to holes that pass through the substrate to the circuit layer and need to be electrically connected to the circuit layer to connect multiple circuit layers. The traditional FR4 substrate is an insulating material. After making the blind hole, a conductive inner wall can be made in the blind hole by electroplating, and the conductive inner wall is used to connect the circuit layers on the two FR4 substrates. Since the aluminum substrate itself is a conductor, if blind holes and semi-blind holes are used for connection, the blind holes and semi-blind holes will be directly connected to the aluminum substrate, which is obviously difficult to do.

[0012] 2. The circuit layer and the insulating thermal conductive layer are bonded by resin glue. The thermal conductivity of the resin glue itself is lower than that of the insulating thermal conductive layer, which will reduce the thermal conductivity effect of the insulating thermal conductive layer on the circuit layer and reduce the heat dissipation of the aluminum substrate. Summary of the invention

[0013] The purpose of the present invention is to provide a method for manufacturing an aluminum-based circuit board and an aluminum-based circuit board, aiming to solve the technical problem in the prior art that it is difficult to manufacture a multilayer board from an aluminum-based circuit board.

[0014] The present invention provides an aluminum-based circuit board, comprising a circuit layer, an insulating heat-conducting layer, and an aluminum-based conductive nail;

[0015] The circuit layer is formed by mechanical processing or cutting; at least one surface of the aluminum substrate is processed to form a convex portion or a concave portion corresponding to the size and shape of the circuit layer; the circuit layer is arranged at the position of the concave portion or the convex portion and corresponds to the shape of the concave portion or the convex portion;

[0016] The aluminum substrate is also provided with at least one through hole; the insulating heat-conductive layer covers the surface of the aluminum substrate and the inner wall of the through hole;

[0017] The conductive nail is installed in the through hole and is non-conductive with the through hole; at least one end of the conductive nail is located on the surface of the aluminum substrate, and both ends of the conductive nail are respectively conductive with the two circuit layers.

[0018] The aluminum-based circuit board disclosed in the present invention can connect the front and back sides of the aluminum-based circuit board or the circuit layers on the multi-layer aluminum substrate through conductive nails, thereby realizing a multi-layer aluminum-based circuit board. In addition, the conductive nails in the multi-layer aluminum-based circuit board can not only conduct electricity, but also conduct heat, so that more heat can be transferred to the aluminum substrate, thereby improving the heat dissipation performance of the entire aluminum-based circuit board.

[0019] The invention also discloses a method for manufacturing an aluminum-based circuit board.

[0020] The method comprises:

[0021] Step S1: Obtaining the dimension data of the designed circuit layer;

[0022] Step S2: According to the size data, the copper foil is mechanically processed or cut to form a circuit layer;

[0023] Step S3: processing the aluminum substrate according to the size data, so that a convex portion or a concave portion that matches the size of the circuit layer is formed on at least one surface of the aluminum substrate, thereby forming a first substrate;

[0024] Step S4: drilling holes through the first substrate to form a second substrate;

[0025] Step S5: providing an insulating heat-conducting layer 12 on the surface of the second substrate and the inner wall of the through hole;

[0026] Step S6: installing a conductive nail in the through hole that needs to be conductive, so that at least one end of the conductive nail is located on the surface of the second substrate, and the conductive nail and the through hole are non-conductive;

[0027] Step S71: Take two layers of the circuit layers and a second substrate; fix the circuit layers at the positions of the convex parts or concave parts on the two opposite surfaces of the second substrate; the shape of each circuit layer corresponds to the shape of the convex part or concave part on the surface of the second substrate to be fixed, and the two ends of the conductive nail are respectively connected to the two circuit layers; or

[0028] Step S72: taking at least three layers of the circuit layers and at least two of the second substrates; interlacing the second substrates between the plurality of the circuit layers; the shape of each of the circuit layers respectively corresponds to the shape of the convex or concave portion on the surface of the second substrate to be fixed, and the two ends of the conductive nail are respectively connected to the two circuit layers;

[0029] Step S8: Fixing the plurality of circuit layers and the second substrate.

[0030] The present invention forms the circuit layer by mechanical precision machining, and can realize precise control of the size of the circuit layer; the aluminum substrate is processed by precision machining to produce convex parts and concave parts, and when the circuit layer is located between two adjacent aluminum substrates, the circuit layer is clamped by the convex parts or concave parts on the surfaces of the two aluminum substrates, which can maximize the contact area between the circuit layer and the aluminum substrate and improve the heat dissipation performance. In addition, the aluminum substrate is processed by mechanical machining, which can facilitate drilling and produce through holes for installing conductive nails. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1It is a schematic diagram of the existing structure of an aluminum-based circuit board;

[0032] Figure 2 It is a schematic diagram of the structure of the aluminum-based circuit board of the present invention;

[0033] Figure 3 is a cross-sectional view of the aluminum-based circuit board of the present invention at the through hole;

[0034] Figure 4 yes Figure 3 A partial enlarged view of . DETAILED DESCRIPTION

[0035] The present invention will be further described and illustrated below in conjunction with specific embodiments and accompanying drawings:

[0036] Please refer to Figure 2 and Figure 3 The present invention discloses an aluminum-based circuit board 100 , which includes a circuit layer 11 , an insulating heat-conducting layer 12 , an aluminum substrate 13 and a conductive nail 14 .

[0037] Wherein, the circuit layer 11 is a conductive layer, which is made of copper foil through precision machining. In the present invention, when making the circuit layer 11, the copper foil is firstly mechanically processed or cut according to the size data of the designed circuit layer 11; the size data mentioned here includes: the design shape of the circuit layer 11, the thickness of the circuit layer 11, the spacing and line width between each wiring line of the circuit layer 11, the pad position designed by the circuit layer 11, the plug interface position and shape, etc. The circuit layer 11 is obtained by mechanically processing the copper foil. On the one hand, it can be precisely processed. Compared with the traditional chemical etching method, it can obtain more precise dimensional accuracy, and it is also conducive to ensuring the wiring thickness of the circuit layer 11, which is conducive to the production of thick circuits, generally reaching more than 4oz; in addition, it can overcome the influence of thick wiring on the inner wall b of the wiring during the etching process, and prevent the wiring from being affected by uneven etching, resulting in a narrow part of the circuit. In addition, the circuit layer 11 is processed by mechanical processing, and the processing efficiency is relatively high, and there will be no waste liquid pollution caused by etching.

[0038] In the present invention, the aluminum substrate 13 is made of aluminum raw material. During the manufacturing process, a convex part or a concave part that matches the size data of the designed circuit layer 11 is processed at the position corresponding to the aluminum substrate 13 where the circuit layer 11 is installed, wherein the processing of the concave part is performed by mechanical milling, and the processing of the convex part is performed by mechanical milling to form a convex part from the reserved part by removing other redundant parts. The aluminum substrate 13 after mechanical processing is the first substrate, and the shape of the concave part or the convex part on the surface of the first substrate is consistent with the shape and size of the circuit layer 11 to be connected.

[0039] In the present invention, the first substrate is drilled after being manufactured, and the drilled holes include through holes a, fixing holes, test holes, etc. The positions of the holes are also based on the corresponding positions of the designed circuit layer 11. For example, if a through hole a is designed at one position of the designed circuit layer 11 for connecting another circuit layer 11, then when processing the first substrate, it is necessary to drill a hole at the position of the through hole a to ensure that the position of the hole corresponds to the position of the through hole a of the designed circuit layer 11. After manufacturing, a second substrate 13b with various hole structures is formed.

[0040] After the above operations are completed, the second substrate 13b is subjected to insulation treatment, and the treatment method is: an insulating heat-conducting layer 12 is set on the surface of the second substrate 13b and the inner walls b of all through holes a. When setting the insulating heat-conducting layer 12: the second substrate 13b is immersed in an insulating heat-conducting molten liquid, and the second substrate 13b is vibrated during the immersion process so that the insulating heat-conducting molten liquid covers the surface of the second substrate 13b and the inner walls b of the through holes a. During the immersion process, vibrating the second substrate 13b can ensure that the insulating heat-conducting molten liquid enters the through holes a and covers the entire inner walls b of the through holes a, and can also make the immersion on the surface of the second substrate 13b more uniform.

[0041] After soaking, the second substrate 13b is taken out from the insulating heat-conducting molten liquid, and the second substrate 13b is centrifugally swung and the insulating heat-conducting liquid is heated to solidify, thereby forming an insulating heat-conducting layer 12 on the second substrate 13b.

[0042] In the present invention, centrifugally shaking the second substrate 13b can remove excess insulating heat-conducting molten liquid adhering to the surface of the second substrate 13b, so that an insulating heat-conducting layer 12 with a substantially uniform thickness is formed on the surface of the second substrate 13b.

[0043] The conductive nail 14 included in the aluminum-based circuit board 100 of the present invention is made of metal material and can conduct electricity, preferably pure copper with excellent conductivity. After a uniform insulating heat-conducting layer 12 is provided on the second substrate 13b, the conductive nail 14 is installed in the through hole a so that at least one end of the conductive nail 14 is located on the surface of the second substrate 13b, that is, one end of the conductive nail 14 can contact or weld with the circuit layer 11 located on the surface of the second substrate 13b, thereby achieving conduction. The two ends of the conductive nail 14 are respectively connected to the two circuit layers 11, which means that: the two ends of the conductive nail 14 are respectively connected to the two circuit layers 11 on the two opposite surfaces of the same second substrate 13b, or one end of the conductive nail 14 is connected to the circuit layer 11 on one surface of one second substrate 13b, and the other end of the conductive nail 14 is connected to the circuit layer 11 on one surface of another second substrate 13b.

[0044] After the conductive nail 14 is installed in the through hole a, it is not electrically conductive with the through hole a.

[0045] In the present invention, when installing the conductive nail 14, a conductive nail 14 of a suitable length is selected for installation according to the number of layers of the circuit board 100 and the position of the circuit layer 11 to be conducted, and the multi-layer aluminum substrate 13, that is, the second substrate 13b and the circuit layer 11 are fixed to each other, wherein the fixing methods include fixing by rivets, fixing by heat dissipation glue, etc.

[0046] like Figure 2 For example, when there is only one second substrate 13b, and the circuit layer 11 has two layers, which are respectively arranged on the two surfaces of the second substrate 13b, the two layers of the circuit layer 11 are prepared, and one second substrate 13b is provided; the circuit layers 11 are fixed on the two opposite surfaces of the second substrate 13b; the shape of each circuit layer 11 corresponds to the shape of the convex part or concave part of the surface of the fixed second substrate 13b, and the two ends of the conductive nail 14 are respectively connected to the two circuit layers 11. In other words, the conductive nail 14 passes through the second substrate 13b, and the two ends are respectively in contact with or welded to the circuit layers 11 connected to the two surfaces of the second substrate 13b.

[0047] In this embodiment, it is preferred that the diameter of the conductive nail 14 and the diameter of the through hole a are interference fit and contact each other. When one circuit layer 11 is conductively connected to another circuit layer 11 through the conductive nail 14, the conductive nail 14 can not only conductively connect the two circuit layers 11 but also transfer its own heat to the aluminum substrate 13 through the inner wall b of the through hole a, thereby improving the heat absorption of the aluminum substrate 13 and the heat dissipation effect on the circuit layer 11.

[0048] like Figure 3 For another example: when there are two second substrates 13b and three circuit layers 11, take the three circuit layers 11 and two second substrates 13b; insert the second substrates 13b between the circuit layers 11; the shape of each circuit layer 11 corresponds to the shape of the convex part 151 or the concave part 152 on the surface of the fixed second substrate 13b, and the two ends of the conductive nail 14 are respectively connected to the two circuit layers 11. In order to more clearly describe the connection method of the conductive nail 14, refer to Figure 3, the applicant named the three circuit layers as circuit 1, circuit 2 and circuit 3 in sequence, and named the two second substrates 13b as substrate 1 and substrate 2; wherein, when the conductive nail 14 needs to connect circuit 1 with circuit 2, the length of the conductive nail 14 is basically adapted to the thickness of one aluminum substrate 13; at this time, the conductive nail 14 passes through the substrate 1, and the two ends of the conductive nail 14 are respectively located on the two surfaces of the substrate 1, one end of the conductive nail 14 is welded or contacted with the circuit 1, and the other end of the conductive nail 14 is welded or contacted with the circuit 2; when the conductive nail 14 needs to connect the circuit 1 with the circuit 3 When connecting, the length of the conductive nail 14 is basically adapted to the thickness of the two aluminum substrates 13, the through holes a on the two substrates 1 correspond to the through holes a on the substrate 2, and after the conductive nail 14 passes through the two through holes a at one time, the two ends are exposed on the upper surface of the substrate 1 and the lower surface of the substrate 2 respectively. When the circuit 1 is fixed on the upper surface of the substrate 1, the circuit 3 is fixed on the lower surface of the substrate 2, and the two second substrates 13b and the three-layer circuit layer 11 are pressed and fixed, the circuit 1 and the circuit 3 are welded or contacted to each other at the position of the conductive nail 14, thereby realizing the conduction of the multi-layer circuit layer 11.

[0049] In the present invention, each aluminum-based circuit board 100 may include multiple through holes a for installing conductive nails 14, and the circuit layers 11 connected to each conductive nail 14 are not exactly the same. In this way, it is possible to achieve circuit layer 11 conduction between multilayer circuit boards 100 similar to the prior art through blind holes or semi-blind holes.

[0050] In the present invention, the aluminum-based circuit board 100 has multiple layers. When installing the circuit layer 11, it is necessary to fix and install them layer by layer, for example, placing the circuit layer 11 and the aluminum substrate 13 from bottom to top. This manufacturing method is relatively simple.

[0051] In the present invention, the conductive nail 14 in the through hole a can also realize the positioning between the multi-layer circuit layer 11 and the aluminum substrate 13 to prevent deviation during the pressing process.

[0052] In the present invention, the number of circuit layers 11 and aluminum substrates 13 can be further increased. It is only necessary to open corresponding through holes a at the positions of the circuit layers 11 that need to be conducted according to the dimensions in the design data, select conductive nails 14 of appropriate length and install them.

[0053] like Figure 3In the present invention, when the circuit layer 11 is located between two aluminum substrates 13, it is preferred that: the surface of one aluminum substrate 13 is provided with a convex portion 151, and the surface of the other aluminum substrate 13 is provided with a concave portion 152, and the shapes and positions of the convex portions 151 and the concave portions 152 located on the surfaces of the two aluminum substrates 13 are adapted to each other; at this time, when the circuit layer 11 is installed on the convex portion 151 on the surface of one aluminum substrate 13, the concave portion 152 on the surface of the other aluminum substrate 13 is pressed against the convex portion 151, so that the circuit layer 11 can be wrapped in the space formed between the convex portion 151 and the concave portion 152. At this time, the upper and lower surfaces of the circuit layer 11 are respectively in contact with the two aluminum substrates 13, which can improve the thermal conductivity and heat dissipation performance; at the same time, the vertical side wall of the circuit layer 11 is also in contact with the aluminum substrate 13 or is close to the aluminum substrate 13, and the circuit layer 11 can also conduct heat to at least one aluminum substrate 13 through the vertical side wall at the same time, further improving the thermal conductivity.

[0054] In the present invention, the through hole a is located at the convex part 151 or the concave part 152 of at least one surface of the second substrate 13b. That is to say, when the circuit layer 11 is fixed at the convex part 151 or the concave part 152 of the second substrate 13b, it can be pressed against or pressed against the surface of the conductive nail 14 in the through hole a, and even welding operation is not required at this time. Moreover, after the circuit layer 11 is installed and fixed, the conductive nail 14 is covered and will not be exposed; especially when the conductive nail 14 is connected at the outermost surface of the aluminum-based circuit board 100, the overall structure can be ensured to be beautiful.

[0055] like Figure 4 In the present invention, the through hole a includes an inner wall b, and an inclined portion c located at both ends of the through hole a and connected to the surface of the aluminum substrate 13, the inclined portion is connected to the inner wall b, and the outer diameter of the inclined portion c gradually increases from the inner wall b toward the surface of the aluminum substrate 13. That is, the two ends of the through hole a form a gourd-shaped mouth with a large outside and a small inside.

[0056] The conductive nail 14 includes a rod portion 141 and an end portion 142, wherein the end portion 142 is located at both ends of the rod portion 141, and the end portion 142 extends from the rod portion 141 toward a direction away from the rod portion 141, and the outer diameter of the end portion 142 away from the rod portion 141 is larger than that of the rod portion 141; the connection surface between the end portion 142 and the rod portion 141 is inclined.

[0057] In the present invention, when the conductive nail 14 is installed in the through hole a, the end 142 is located in the inclined portion c, and the rod portion 141 is located in the inner wall b; the size of the end 142 is adapted to the inclined portion c. At this time, the gourd-shaped shape of the conductive nail 14 can ensure the stability of the two ends of the conductive nail 14 in the through hole a, while also increasing the contact area with the through hole a, thereby improving the heat conduction and heat dissipation efficiency.

[0058] The aluminum-based circuit board 100 of the present invention manufactured according to the method of the present invention overcomes the technical problem of the prior art that it is inconvenient to manufacture a multi-layer circuit board 100 with a multi-layer circuit layer 11 through the conductive nails 14, and at the same time, the conductive nails 14 also improve the thermal conductivity and heat dissipation efficiency of the multi-layer aluminum-based circuit board 100.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for manufacturing an aluminum-based circuit board, characterized in that: The method comprises: Step S1: Obtaining the dimension data of the designed circuit layer; Step S2: According to the size data, the copper foil is mechanically processed or cut to form a circuit layer; Step S3: processing the aluminum substrate according to the size data, so that a convex portion or a concave portion that matches the size of the circuit layer is formed on at least one surface of the aluminum substrate, thereby forming a first substrate; Step S4: drilling a through hole in the first substrate to form a second substrate, wherein the through hole is located at the convex portion or concave portion of at least one surface of the aluminum substrate; Step S5: providing an insulating heat-conducting layer on the surface of the second substrate and the inner wall of the through hole; Step S6: selecting a conductive nail of corresponding length, wherein the conductive nail is made of metal; installing the conductive nail in the through hole that needs to be conductive, so that at least one end of the conductive nail is located on the surface of the second substrate, and the conductive nail and the through hole are non-conductive; Step S71: Take two layers of the circuit layers and a second substrate; fix the circuit layers at the positions of the convex parts or concave parts on the two opposite surfaces of the second substrate; the shape of each circuit layer corresponds to the shape of the convex part or concave part on the surface of the second substrate to be fixed, and the two ends of the conductive nail are respectively connected to the two circuit layers; or Step S72: taking at least three layers of the circuit layers and at least two of the second substrates; interlacing the second substrates between the plurality of the circuit layers; the shape of each of the circuit layers respectively corresponds to the shape of the convex or concave portion on the surface of the second substrate to be fixed, and the two ends of the conductive nail are respectively connected to the two circuit layers; Step S8: fixing the plurality of circuit layers and the second substrate; Wherein, the step S5 comprises: Step S51: immersing the second substrate in an insulating thermally conductive melt, and vibrating the second substrate during the immersion process, so that the insulating thermally conductive melt covers the surface of the second substrate and the inner wall of the through hole; Step S52: taking out the second substrate from the insulating heat-conducting molten liquid, centrifugally spinning the second substrate and heating and curing the insulating heat-conducting molten liquid, thereby forming an insulating heat-conducting layer on the second substrate; The two ends of the conductive nail are respectively connected to the two circuit layers, which means that: the two ends of the conductive nail are respectively connected to the two circuit layers on the two opposite surfaces of the same second substrate, or one end of the conductive nail is connected to the circuit layer on one surface of one second substrate, and the other end of the conductive nail is connected to the circuit layer on one surface of another second substrate.

2. The method for manufacturing an aluminum-based circuit board according to claim 1, characterized in that: The processing of the aluminum substrate in step S3 includes a CNC milling operation to remove excess base material from the surface of the aluminum substrate to form a concave portion or a convex portion with the same size as the circuit layer.

3. An aluminum-based circuit board, comprising a circuit layer, an insulating heat-conducting layer and an aluminum substrate, characterized in that: The aluminum-based circuit board is manufactured by the aluminum-based circuit board manufacturing method according to claim 1, and the aluminum-based circuit board further comprises a conductive nail; The circuit layer is formed by mechanical processing or cutting; At least one surface of the aluminum substrate is processed to form a convex portion or a concave portion corresponding to the size and shape of the circuit layer; the circuit layer is arranged at the position of the concave portion or the convex portion and corresponds to the shape of the concave portion or the convex portion; The aluminum substrate is also provided with at least one through hole, and the position of the through hole is located at the convex part or the concave part of at least one surface of the aluminum substrate; the insulating heat-conductive layer covers the surface of the aluminum substrate and the inner wall of the through hole; Among them, the conductive nail is made of metal, and the conductive nail of corresponding length is installed in the through hole and is non-conductive with the through hole, so that at least one end of the conductive nail is located on the surface of the aluminum substrate, and the two ends of the conductive nail are respectively connected to the two circuit layers.

4. The aluminum-based circuit board according to claim 3, characterized in that: The through hole comprises an inner wall, and inclined portions located at both ends of the through hole and connected to the surface of the aluminum substrate, the inclined portions are connected to the inner wall, and the outer diameter of the inclined portions gradually increases from the inner wall toward the surface of the aluminum substrate; the conductive nail comprises a rod and an end portion, the end portion is located at both ends of the rod portion, the end portion extends from the rod portion toward a direction away from the rod portion, and the outer diameter of the end portion away from the rod portion is larger than that of the rod portion; the connection surface between the end portion and the rod portion is arranged obliquely; After the conductive nail is installed in the through hole, the end is located at the inclined portion, and the rod is located inside the inner wall; the size of the end is adapted to the inclined portion.

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