Circuit board and manufacturing method thereof

Abstract

The present invention discloses a circuit board and a manufacturing method thereof in the field of embedded circuit board performance optimization technology, aiming to solve the problem in the prior art that power components lack output channels and are prone to electromagnetic interference to surrounding circuits. It includes: making an insulating layer on a heat-conducting carrier, shielding the electromagnetic interference of the component to the surrounding circuits through the insulating layer and improving the voltage resistance of the component; on the basis of outputting the first circuit layer of the connected component and the second circuit layer of the second circuit board, a blind hole groove connected to the edge of the heat-conducting carrier is opened on the second circuit board after the first circuit board and the layer is added, and a first conductor connected to the edge contact of the heat-conducting carrier is arranged in the blind hole groove, so as to provide a new output channel for the component, thereby greatly improving the number of output channels and output capacity of the component.

Description

Technical Field

[0001] The invention relates to a circuit board and a manufacturing method thereof, belonging to the technical field of embedded circuit board performance optimization. Background Art

[0002] The power components used in electric vehicles, high-speed railways and other electrical facilities are embedded in the circuit boards to improve the switching efficiency of the power components and reduce the inductance effect, while reducing the overall energy consumption.

[0003] After the power components are embedded in the circuit board, new problems arise. When the power components are working, the heat will accumulate in the circuit board. Therefore, the industry sets up additional heat-conducting carriers in the power components for heat conduction. However, after the power components are mounted on the heat-conducting carriers, the heat-conducting carriers lack electrical connection channels with the outside world, resulting in the lack of output channels for the power components. Secondly, after being embedded in the circuit board, the power components are prone to electromagnetic interference to the surrounding circuits, resulting in the limitation of the working voltage of the components. Summary of the invention

[0004] The purpose of the present application is to overcome the deficiencies in the prior art and to provide a circuit board having multiple output channels, strong output capability and avoiding electromagnetic interference to surrounding circuits and a method for manufacturing the same.

[0005] In order to achieve the above objectives, this application is implemented by adopting the following technical solutions: In a first aspect, the present application provides a method for manufacturing a circuit board, comprising: The component is packaged on a first side of the heat-conducting carrier, and an insulating layer is provided on a second side of the heat-conducting carrier to obtain a first semi-finished product; Cutting a second groove on the first circuit board, placing the first semi-finished product into the second groove, and obtaining a second semi-finished product; Adding a second circuit board on the surface of the second semi-finished product; Connecting the second circuit layer of the second circuit board to the first circuit layer of the component to obtain a third semi-finished product; A blind hole groove connected to the edge of the heat conducting carrier is opened on the third semi-finished product, and a first conductor connected to the edge contact of the heat conducting carrier and the second circuit layer is made in the blind hole groove to complete the production of the circuit board.

[0006] In some embodiments of the first aspect, encapsulating the component on the first side of the heat conductive carrier includes opening a first groove on the first side of the heat conductive carrier for embedding the component.

[0007] In some embodiments of the first aspect, connecting the second circuit layer of the second circuit board to the first circuit layer of the component includes: Opening a first blind hole on the second circuit board corresponding to the position of the first circuit layer; The first blind hole is copper plated to make the second circuit layer and the first circuit layer conductive through the copper layer of the first blind hole.

[0008] In some embodiments of the first aspect, a second heat-conducting carrier is disposed on a side of the insulating layer facing away from the heat-conducting carrier; The second circuit board is added to the first side of the heat conducting carrier, and a third circuit board is added to the surface of the second heat conducting carrier, and the third circuit layer of the third circuit board is connected to the second heat conducting carrier to obtain a third semi-finished product.

[0009] In some embodiments of the first aspect, a second blind hole is opened on the third circuit board, and the second blind hole is connected to the second heat conducting carrier; The second blind hole is copper plated to make the third circuit layer and the second heat conducting carrier conduction through the copper layer of the second blind hole.

[0010] In some embodiments of the first aspect, the blind hole groove comprises a segmental groove corresponding to each contact point of the edge of the heat conductive carrier or a regional groove connecting multiple contacts of the edge of the heat conductive carrier.

[0011] In a second aspect, the present application further provides a circuit board, comprising: A first circuit board and a heat-conducting carrier, wherein the first circuit board is provided with a second groove, and the heat-conducting carrier is arranged in the second groove; An element is packaged on the first side of the heat-conducting carrier, and the element includes a first circuit layer; an insulating layer is provided on the second side of the heat-conducting carrier; a second circuit board connected to the first circuit board, wherein the second circuit board is provided with a second circuit layer connected to the first circuit layer; A blind hole groove corresponding to the edge of the heat conducting carrier is opened on the first circuit board, and a first conductor is made in the blind hole groove. The first conductor is used to connect the edge contact of the heat conducting carrier and the second circuit layer.

[0012] In some embodiments of the second aspect, a first blind hole is opened at a position of the first circuit board corresponding to the first circuit layer, and the inner wall of the first blind hole is copper-plated to enable the second circuit layer to connect to the first circuit layer through the copper layer of the first blind hole.

[0013] In some embodiments of the second aspect, the second circuit board is located on the first side of the heat conductive carrier; the insulating layer is also connected to the second heat conductive carrier, the second heat conductive carrier is connected to the third circuit board, the third circuit board includes a third circuit layer, and the third circuit layer is connected to the second heat conductive carrier.

[0014] In some embodiments of the second aspect, the third circuit board has a second blind hole, the second blind hole is connected to the second heat conductive carrier, the inner wall of the second blind hole is copper-plated, and the third circuit layer is connected to the second heat conductive carrier through the copper layer of the second blind hole.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The circuit board and the manufacturing method thereof provided by the present application manufacture an insulating layer on a heat-conducting carrier, and shield the electromagnetic interference of the component to the surrounding circuits through the insulating layer, thereby improving the voltage operating upper limit of the component; on the basis of outputting by connecting the first circuit layer of the component with the second circuit layer of the second circuit board, a blind hole groove connected to the edge of the heat-conducting carrier is opened on the first circuit board and the second circuit board after adding layers, and a first conductor connected to the edge contact of the heat-conducting carrier is arranged in the blind hole groove, thereby providing a new output channel for the component, thereby greatly improving the number of output channels and output capacity of the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a schematic cross-sectional view of the structure of a first semi-finished product obtained when manufacturing the circuit board provided in this embodiment; Figure 2 is a schematic cross-sectional view of the structure of a second semi-finished product obtained when manufacturing the circuit board provided in this embodiment; Figure 3 is a schematic cross-sectional view of the structure of a second semi-finished product based on a second laminate obtained when manufacturing the circuit board provided in this embodiment; Figure 4 is a schematic cross-sectional view of a structure in which a second circuit board is added to the surface of a second semi-finished product obtained during the manufacture of the circuit board provided in this embodiment; Figure 5 is a schematic cross-sectional view of a structure in which a second circuit board is added to the surface of a second semi-finished product based on a second laminate obtained during the manufacture of the circuit board provided in this embodiment; Figure 6 is a schematic cross-sectional view of the structure of a third semi-finished product obtained when manufacturing the circuit board provided in this embodiment; Figure 7 is a schematic cross-sectional view of the structure of a circuit board provided in this embodiment in which a blind hole groove is opened on a third semi-finished product during manufacturing; Figure 8It is a schematic cross-sectional view of the structure of a circuit board provided in this embodiment, in which a blind hole groove is opened on a third semi-finished product based on a second laminated board during manufacturing; Fig. 9 It is a schematic top view of the structure of providing a segmented groove on a third semi-finished product when manufacturing the circuit board provided in this embodiment; Fig.10 It is a schematic top view of the structure of opening a regional groove on the third semi-finished product when manufacturing the circuit board provided by this embodiment; Fig.11 is a flowchart of the steps of the method for manufacturing a circuit board provided in this embodiment; In the figure: 1, component; 2, first groove; 3, first circuit layer; 4, heat-conducting carrier; 5, insulating layer; 6, first circuit board; 7, second laminate; 8, second circuit board; 8.1, second circuit layer; 9, blind hole groove; 9.1, segment groove; 9.2, regional groove; 10, first conductor; 11, second heat-conducting carrier; 12, third circuit board; 12.1, third circuit layer; 13, first blind hole; 14, second blind hole. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of this application / this application to clearly and completely describe the technical solutions in the embodiments of this application / this application. Obviously, the described embodiments are only part of the embodiments of this application / this application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the application / this application and its application or use. Embodiment 1:

[0019] This embodiment provides a method for manufacturing a circuit board.

[0020] refer to Fig.11 The method for manufacturing a circuit board provided in this embodiment includes the following steps: refer to Figure 1 , encapsulating the component 1 on the first side of the heat-conducting carrier 4, and providing an insulating layer 5 on the second side of the heat-conducting carrier 4, to obtain a first semi-finished product; wherein the heat-conducting carrier 4 is mainly used to dissipate heat for the component 1, and the heat-conducting carrier 4 also has an output function for the component 1 encapsulated thereon, specifically, a circuit connected to the contact pin of the component 1 is arranged on the heat-conducting carrier 4, and the circuit is connected to the edge contact, or other forms may be adopted; and the insulating layer 5 located on the second side of the heat-conducting carrier 4 is mainly used to electromagnetically shield the component 1 to prevent the component 1 from interfering with other circuits; A second groove is formed on the first circuit board 6, and the first semi-finished product is placed in the second groove to obtain a second semi-finished product; A second circuit board 8 is added to the surface of the second semi-finished product; the second circuit board 8 is the output base of the component 1; The second circuit layer 8.1 of the second circuit board 8 is connected with the first circuit layer 3 of the component 1 to obtain a third semi-finished product; the component 1 in the third semi-finished product can be output through the first circuit layer 3 and the second circuit layer 8.1 on the second circuit board 8; as one embodiment, the first circuit layer 3 can be arranged on the side of the component 1 away from the heat conductive carrier 4; A blind hole groove 9 connected to the edge of the heat-conducting carrier 4 is opened on the third semi-finished product, and a first conductor 10 connected to the edge contact of the heat-conducting carrier 4 and the second circuit layer 8.1 is made in the blind hole groove 9 to complete the production of the circuit board; in addition to outputting through the first circuit layer 3 and the second circuit layer 8.1 on the second circuit board 8, the component 1 can also be connected to the first conductor 10 through the circuit in the heat-conducting carrier 4 and the edge contact, and then output from the first conductor 10 to the second circuit layer 8.1, and these two output paths avoid the insulating layer 5, and the component 1 has a stronger output capacity and output channel than the components in the traditional circuit board production method through two-way external output.

[0021] In summary, the method for manufacturing a circuit board provided in this embodiment manufactures an insulating layer 5 on a heat-conducting carrier 4, and uses the insulating layer 5 to shield the electromagnetic interference of the component 1 on the surrounding circuits, thereby reducing the probability of high-voltage breakdown and increasing the upper limit of the operating voltage of the component 1; on the basis of connecting the first circuit layer 3 of the component 1 with the second circuit layer 8.1 of the second circuit board 8 for output, a blind hole groove 9 connected to the edge of the heat-conducting carrier 4 is opened on the first circuit board 6 and on the second circuit board 8 after adding layers, and a first conductor 10 connected to the edge contact of the heat-conducting carrier 4 is arranged in the blind hole groove 9, so as to provide a new output channel for the component 1, thereby greatly improving the number of output channels and the output capacity of the component 1. Embodiment 2:

[0022] This embodiment provides a method for manufacturing a circuit board. This embodiment is optimized on the basis of the first embodiment to improve the technical effect and refine the technical solution. For the contents not fully described in this embodiment, please refer to the first embodiment.

[0023] As one example, refer to Figure 1 , encapsulating the component 1 on the first side of the heat conducting carrier 4, including, opening a first groove 2 for embedding the component 1 on the first side of the heat conducting carrier 4. The first groove 2 is made by deep fishing, polishing, electroplating, punching, concave and convex mold pressing, or a combination of the above methods. As one embodiment, refer to Figure 1 The depth of the first groove 2 can match the thickness of the component 1 to prevent the component 1 from being sunken when adding layers after being packaged in the first groove 2. As one embodiment, the packaging method of the component 1 includes silver sintering or metal welding.

[0024] As one example, refer to Figure 6 , connecting the second circuit layer 8.1 of the second circuit board 8 with the first circuit layer 3 of the component 1, including, corresponding to the position of the first circuit layer 3, opening a first blind hole 13 on the second circuit board 8; copper-plating the first blind hole 13, so that the second circuit layer 8.1 and the first circuit layer 3 are connected through the copper layer in the first blind hole 13. Among them, the copper plating of the first blind hole 13 can be achieved in other forms known in the art, which will not be repeated here. As one embodiment, the second circuit layer 8.1 of the second circuit board 8 is generally obtained by laying copper foil on the side away from the first circuit layer 3, and then etching the copper foil. The opening of the first blind hole 13 can be achieved in other forms known in the art, such as blind fishing, laser or machine drilling process, or even more other known forms, which will not be repeated here.

[0025] The insulating layer 5 plays a role in shielding the electromagnetic interference of the component 1. Figure 4 , Figure 6 and Figure 7 Therefore, a second heat-conducting carrier 11 can be arranged on the side of the insulating layer 5 away from the heat-conducting carrier 4, and the second circuit board 8 is arranged on the first side of the heat-conducting carrier 4, and a third circuit board 12 similar to the second circuit board 8 is added on the surface of the second heat-conducting carrier 11, and the third circuit layer 12.1 of the third circuit board 12 is connected to the second heat-conducting carrier 11, and the second heat-conducting carrier 11 can conduct electrical output to the third circuit layer 12.1 to obtain a third semi-finished product.

[0026] Correspondingly, refer to Figure 6 A second blind hole 14 is opened on the third circuit board 12, and the second blind hole 14 is connected to the second heat conducting carrier 11; the second blind hole 14 is copper plated, so that the third circuit layer 12.1 and the second heat conducting carrier 11 are connected through the copper layer in the second blind hole 14. The opening method and copper plating method of the second blind hole 14 can refer to the first blind hole 13, and will not be repeated here.

[0027] refer to Fig. 9 and Fig.10 As one embodiment, the blind hole groove 9 includes a plurality of segment grooves 9.1 corresponding to the edge contacts of the heat conducting carrier 4 or a regional groove 9.2 connecting the plurality of contacts at the edge of the heat conducting carrier 4. It can also be a full-cover groove or a combined groove.

[0028] As one example, Figure 3 , Figure 5 and Figure 8 The first circuit board 6 can be a traditional single-layer circuit board or a second laminate board 7 .

[0029] As one embodiment, the second groove can be realized in other forms known in the art, such as blind fishing, laser, machine drilling process, punching or combination, or even more other known forms, which will not be described in detail here.

[0030] As one embodiment, the method of disposing the first conductor 10 in the blind hole slot 9 includes electroplating or filling a conductive material. Embodiment three:

[0031] This embodiment provides a circuit board. The circuit board provided in this embodiment can be manufactured by the manufacturing method of the circuit board provided in the first or second embodiment.

[0032] refer to Figures 1 to 10 The circuit board provided in this embodiment includes a first circuit board 6 and a heat-conducting carrier 4, the first circuit board 6 is provided with a second groove, and the heat-conducting carrier 4 is arranged in the second groove; the circuit board provided in this embodiment also includes a component 1, the component 1 is encapsulated on the first side of the heat-conducting carrier 4, and the component 1 includes a first circuit layer 3; the second side of the heat-conducting carrier 4 is provided with an insulating layer 5; the circuit board provided in this embodiment also includes a second circuit board 8, the second circuit board 8 is connected to the first circuit board 6, and the second circuit board 8 is provided with a second circuit layer 8.1 connected to the first circuit layer 3; a blind hole groove 9 corresponding to the edge of the heat-conducting carrier 4 is opened on the first circuit board 6, and a first conductor 10 is made in the blind hole groove 9, and the first conductor 10 is used to connect the edge contact of the heat-conducting carrier 4 and the second circuit layer 8.1.

[0033] In the circuit board provided in this embodiment, an insulating layer 5 is made on the heat-conducting carrier 4, and the electromagnetic interference of the component 1 to the surrounding circuits is shielded by the insulating layer 5; on the basis of connecting the first circuit layer 3 of the component 1 and the second circuit layer 8.1 of the second circuit board 8 for output, a blind hole groove 9 connected to the edge of the heat-conducting carrier 4 is opened on the second circuit board 8 after layer addition, and a first conductor 10 connected to the edge contact of the heat-conducting carrier 4 is arranged in the blind hole groove 9, so as to provide a new output channel for the component 1, thereby greatly improving the number of output channels and the output capacity of the component 1.

[0034] As one embodiment, a first blind hole 13 is opened at a position corresponding to the first circuit layer 3 on the first circuit board 6, and the inner wall of the first blind hole 13 is copper-plated so that the second circuit layer 8.1 is connected to the first circuit layer 3 through the copper layer of the first blind hole 13.

[0035] As one embodiment, the second circuit board 8 is located on the first side of the heat conductive carrier 4; the insulating layer 5 is also connected to the second heat conductive carrier 11, the second heat conductive carrier 11 is connected to the third circuit board 12, the third circuit board 12 includes a third circuit layer 12.1, the third circuit layer 12.1 is connected to the second heat conductive carrier 11, and the second heat conductive carrier 11 can be output through the third circuit layer 12.1.

[0036] As one embodiment, the third circuit board 12 has a second blind hole 14 connected to the second heat conducting carrier 11 . The inner wall of the second blind hole 14 is copper plated. The third circuit layer 12 . 1 is connected to the second heat conducting carrier 11 through the copper layer of the second blind hole 14 .

[0037] As one embodiment, the heat conducting carrier 4 and the second heat conducting carrier 11 may be copper, wherein the insulating layer 5 may be a ceramic substrate or a high thermal conductivity non-metallic composite plate.

[0038] refer to Fig. 9 and Fig.10 As one embodiment, the blind hole groove 9 includes a segment groove 9.1 corresponding to the edge contact of the heat conducting carrier 4 or a regional groove 9.2 connecting multiple contacts at the edge of the heat conducting carrier 4, and can also be a full-covering groove.

[0039] As one embodiment, the first circuit board 6 may be the second laminate board 7. As one embodiment, the first circuit board 6 may be made of an insulating material with glass fiber.

[0040] As one embodiment, the width of the edge of the heat conducting carrier 4 exposed in the blind hole groove 9 is at least greater than 0.1 mm.

[0041] The method for manufacturing the circuit board provided in Example 1 or 2 can be used to manufacture the circuit board provided in this embodiment, and has functional modules and beneficial effects corresponding to the execution method. The circuit board provided in this embodiment has technical effects corresponding to Example 1 or 2, which will not be repeated here.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "provided at", "provided with", "located", "installed", "set", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. "Hinged" includes "rotational connection".

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that: include, The component (1) is packaged on a first side of a heat-conducting carrier (4), and an insulating layer (5) is provided on a second side of the heat-conducting carrier (4), so as to obtain a first semi-finished product; Cutting a second groove on the first circuit board (6), placing the first semi-finished product into the second groove, and obtaining a second semi-finished product; Adding a second circuit board (8) on the surface of the second semi-finished product; Connecting the second circuit layer (8.1) of the second circuit board (8) to the first circuit layer (3) of the component (1) to obtain a third semi-finished product; A blind hole groove (9) connected to the edge of the heat-conducting carrier (4) is provided on the third semi-finished product, and a first conductor (10) connected to the edge contact of the heat-conducting carrier (4) and the second circuit layer (8.1) is manufactured in the blind hole groove (9), thereby completing the manufacture of the circuit board.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The encapsulation of the component (1) on the first side of the heat-conducting carrier (4) comprises: a first groove (2) for embedding the component (1) is provided on the first side of the heat-conducting carrier (4).

3. The method for manufacturing a circuit board according to claim 1, characterized in that: The step of connecting the second circuit layer (8.1) of the second circuit board (8) to the first circuit layer (3) of the component (1) comprises: A first blind hole (13) is opened on the second circuit board (8) corresponding to the position of the first circuit layer (3); The first blind hole (13) is copper plated so that the second circuit layer (8.1) and the first circuit layer (3) are electrically connected via the copper layer of the first blind hole (13).

4. The method for manufacturing a circuit board according to claim 1, wherein A second heat conducting carrier (11) is arranged on a side of the insulating layer (5) facing away from the heat conducting carrier (4); The second circuit board (8) is added to the first side of the heat-conducting carrier (4), and a third circuit board (12) is added to the surface of the second heat-conducting carrier (11), and the third circuit layer (12.1) of the third circuit board (12) is connected to the second heat-conducting carrier (11), so as to obtain a third semi-finished product.

5. The method for manufacturing a circuit board according to claim 4, wherein A second blind hole (14) is provided on the third circuit board (12), and the second blind hole (14) is connected to the second heat conducting carrier (11); The second blind hole (14) is copper plated so that the third circuit layer (12.1) and the second heat conducting carrier (11) are electrically connected via the copper layer of the second blind hole (14).

6. The method for manufacturing a circuit board according to any one of claims 1 to 5, characterized in that: The blind hole groove (9) comprises a segment groove (9.1) corresponding to a contact point on the edge of the heat conducting carrier (4) alone, or a region groove (9.2) connecting multiple contacts on the edge of the heat conducting carrier (4).

7. A circuit board, characterized in that: include, A first circuit board (6) and a heat-conducting carrier (4), wherein the first circuit board (6) is provided with a second groove, and the heat-conducting carrier (4) is arranged in the second groove; An element (1) is packaged on a first side of the heat-conducting carrier (4), wherein the element (1) comprises a first circuit layer (3); an insulating layer (5) is provided on a second side of the heat-conducting carrier (4); A second circuit board (8) connected to the first circuit board (6), the second circuit board (8) being provided with a second circuit layer (8.1) connected to the first circuit layer (3); A blind hole groove (9) corresponding to the edge of the heat-conducting carrier (4) is provided on the first circuit board (6), and a first conductor (10) is manufactured in the blind hole groove (9), wherein the first conductor (10) is used to connect the edge contact of the heat-conducting carrier (4) and the second circuit layer (8.1).

8. The circuit board according to claim 7, characterized in that: A first blind hole (13) is provided on the first circuit board (6) at a position corresponding to the first circuit layer (3); the inner wall of the first blind hole (13) is copper-plated, so that the second circuit layer (8.1) is connected to the first circuit layer (3) through the copper layer of the first blind hole (13).

9. The circuit board according to claim 7, characterized in that: The second circuit board (8) is located on a first side of the heat-conducting carrier (4); the insulating layer (5) is also connected to the second heat-conducting carrier (11); the second heat-conducting carrier (11) is connected to a third circuit board (12); the third circuit board (12) comprises a third circuit layer (12.1); and the third circuit layer (12.1) is in communication with the second heat-conducting carrier (11).

10. The circuit board according to claim 9, characterized in that: The third circuit board (12) is provided with a second blind hole (14), the second blind hole (14) is connected to the second heat-conducting carrier (11), the inner wall of the second blind hole (14) is copper-plated, and the third circuit layer (12.1) is connected to the second heat-conducting carrier (11) through the copper layer of the second blind hole (14).

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