Circuit board and preparation method

Abstract

The invention discloses a circuit board and a manufacturing method. The circuit board comprises a first core board which is provided with a first groove penetrating through the first core board; the first functional device is accommodated in the first groove; the first filling part is filled in the first groove; the first line layer is insulated from the first core plate, the first filling part is located between the first functional device and the first line layer, the first line layer is provided with at least one first through hole, the first groove covers the first through hole in the first direction, and the first direction is perpendicular to the first line layer; the first heat dissipation layer is located on the side, away from the first core board, of the first circuit layer, and the first through hole is further filled with the first heat dissipation layer which is in contact with the first filling part; the material of the first filling part and the material of the first heat dissipation layer both comprise heat dissipation conductive materials. According to the technical scheme, the first functional device is communicated with the first circuit layer while heat dissipation of the first functional device is met, and the reliability of the circuit board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit boards, and in particular to a circuit board and a preparation method thereof. Background Art

[0002] As electronic technology products develop towards thinner, shorter, and larger-scale integration, high-tech electronic products are also increasingly demanding the reserved mounting space and heat dissipation power for chip mounting on circuit boards. In the printed circuit board (PCB) industry, most of the processing technologies for internal embedded components and PCB board laser hole heat dissipation are used to improve space utilization, reduce mounting costs, and increase heat dissipation rates. These two processing technologies for internal embedded components and PCB board laser hole heat dissipation are gradually becoming a development trend of printed circuit boards.

[0003] However, the built-in component technology relies on the use of solder paste, which is prone to reaction during the production process, affecting the reliability of the circuit board. The PCB laser hole heat dissipation technology requires a combination of multiple processes, which affects the reliability of the circuit board. Summary of the invention

[0004] The invention provides a circuit board and a preparation method thereof, so as to solve the technical problem of poor reliability of the existing circuit board.

[0005] According to one aspect of the present invention, there is provided a circuit board, comprising:

[0006] A first core plate having a first groove penetrating through the first core plate;

[0007] a first functional device accommodated in the first groove and a first filling portion filled in the first groove;

[0008] A first circuit layer insulated from the first core board, the first filling portion is located between the first functional device and the first circuit layer, the first circuit layer has at least one first through hole, the first groove covers the first through hole in a first direction, and the first direction is perpendicular to the first circuit layer;

[0009] A first heat dissipation layer is located on a side of the first circuit layer away from the first core board, and the first heat dissipation layer is also filled in the first through hole and in contact with the first filling portion;

[0010] The material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

[0011] Optionally, a material of the first filling portion is the same as a material of the first heat dissipation layer.

[0012] Optionally, the heat dissipating conductive material includes at least one of gold, silver and graphite.

[0013] Optionally, it further includes: a second circuit layer, which is located on a side of the first core board away from the first circuit layer and is insulated from the first core board.

[0014] Optionally, the first through hole includes a top opening away from the first core plate and a bottom opening close to the first core plate;

[0015] Along the direction from the top opening to the bottom opening, the aperture of the first through hole gradually decreases.

[0016] Optionally, the first circuit layer has a plurality of the first through holes;

[0017] The sizes of top openings of at least two of the first through holes are different, or the sizes of bottom openings of at least two of the first through holes are different.

[0018] Optionally, the first functional device is accommodated in the first groove, and a gap between a groove wall of the first groove and a corresponding side of the first functional device is Wa, 0.1 mm≤Wa≤0.3 mm.

[0019] Optionally, the surface flatness of the heat dissipation film layer is less than 0.2 mm.

[0020] According to another aspect of the present invention, a method for preparing a circuit board is provided, which is used to prepare the circuit board according to any embodiment of the present invention, and the preparation method comprises:

[0021] Providing a first core plate having a first groove extending through the first core plate;

[0022] Placing a first functional device in the first groove, and filling the first groove with a heat dissipation conductive material to form a first filling portion;

[0023] forming a first circuit layer on the first core board and forming a first through hole on the first circuit layer;

[0024] forming a first heat dissipation layer on the first circuit layer, wherein the first heat dissipation layer contacts the first filling portion through the first through hole;

[0025] The material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

[0026] Optionally, it also includes:

[0027] A second circuit layer is formed on a side of the first core board away from the first circuit layer.

[0028] In the embodiment of the present invention, a first filling portion is arranged in the first groove to fix the first functional device, a first through hole is opened on the first circuit layer, and a first heat dissipation layer located on the side of the first circuit layer away from the first core board is filled in the first through hole, and the material of the first filling portion and the material of the first heat dissipation layer are both heat dissipation conductive materials. The above technical solution satisfies the heat dissipation of the first functional device while connecting the first functional device to the first circuit layer. In addition, fixing the first functional device with heat dissipation conductive material instead of solder paste can avoid the reaction between solder paste and brown oxide solution during the production process of the circuit board, thereby improving the reliability of the circuit board. Furthermore, compared with the existing PCB board laser hole heat dissipation technology, the first heat dissipation layer is filled in the first through hole, the production cycle is short and the hole wall quality is more stable.

[0029] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 is a schematic diagram of a first circuit board structure provided according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of a second circuit board structure provided according to an embodiment of the present invention;

[0033] Figure 3 is a schematic diagram of a third circuit board structure provided according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of a fourth circuit board structure provided according to an embodiment of the present invention;

[0035] Figure 5 is a schematic flow chart of a method for preparing a circuit board according to an embodiment of the present invention;

[0036] Figure 6 The present invention is a process flow chart of a method for preparing a circuit board provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, any variation of the terms "including" and "having" is intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] Figure 1 is a schematic diagram of a first circuit board structure provided according to an embodiment of the present invention, such as Figure 1 As shown, the circuit board structure includes: a first core board 101, having a first groove 201 passing through the first core board 101; a first functional device 301 accommodated in the first groove 201 and a first filling portion 401 filled in the first groove 201; a first circuit layer 501 insulated from the first core board 101, the first filling portion 401 is located between the first functional device 301 and the first circuit layer 501, the first circuit layer 501 has at least one first through hole 601, the first groove 201 covers the first through hole 601 in a first direction, and the first direction is perpendicular to the first circuit layer 501; a first heat dissipation layer 701, located on a side of the first circuit layer 501 away from the first core board 101, the first heat dissipation layer 701 is also filled in the first through hole 601 and in contact with the first filling portion 401; the material of the first filling portion 401 and the material of the first heat dissipation layer 701 both include heat dissipation conductive material.

[0040] Specifically, the optional first core board 101 is an inner core board of a printed circuit board (PCB). A through-type first groove 201 is provided on the first core board 101, and a first functional device 301 is placed in the first groove 201. The optional first functional device 301 is a semiconductor element, a capacitor, a magnetic core or a combination of elements. The first functional device 301 is fixed in the first groove 201 by filling the first groove 201 with a heat dissipation conductive material. The optional heat dissipation conductive material can be a high molecular conductive thermal conductive polymer, and the high molecular conductive thermal conductive polymer can include at least one of gold, silver and graphite. In addition, the heat dissipation conductive material is a colloidal liquid material. The first circuit layer 501 can be a PCB board, and an insulating layer is provided between the first circuit layer 501 and the first core board 101, so that the first circuit layer 501 and the first core board 101 are insulated. The material of the optional insulating layer is a prepreg. The prepreg is mainly composed of resin and reinforcing material, and plays a role in bonding the first circuit layer 501 and the first core board 101. At least one first through hole 601 is opened on the first circuit layer.

[0041] like Figure 1 As shown, this embodiment is illustrated by taking three first through holes 601 as an example, and the specific number of the first through holes is not limited. The first direction -Z is perpendicular to the first circuit layer 501. In the first direction, the first groove 201 covers the three first through holes 601, that is, the first through holes 601 are arranged directly below the first functional device 301, and the heat generated by the first functional device 301 is directly dissipated through the first through holes 601, which can improve the heat dissipation efficiency. A first heat dissipation layer 701 is arranged on the side of the first circuit layer 501 away from the first core board 101. The first heat dissipation layer 701 is formed of a heat dissipation conductive material. The arrangement of the first heat dissipation layer 701 enhances the heat dissipation effect of the circuit board while making the circuit board surface have anti-oxidation and anti-hygroscopic properties. Further, the first heat dissipation layer 701 is filled in the first through hole 601, so that the first filling portion 401 and the first heat dissipation layer 701 can form an integral structure. The advantage of such an arrangement is that while satisfying the heat dissipation of the first functional device 301, the first functional device 401 can also be connected to the first circuit layer 501.

[0042] In the embodiment of the present invention, a first filling portion is arranged in the first groove to fix the first functional device, a first through hole is opened on the first circuit layer, and a first heat dissipation layer located on the side of the first circuit layer away from the first core board is filled in the first through hole, and the material of the first filling portion and the material of the first heat dissipation layer are both heat dissipation conductive materials. The above technical solution satisfies the heat dissipation of the first functional device while connecting the first functional device to the first circuit layer. In addition, fixing the first functional device with heat dissipation conductive material instead of solder paste can avoid the reaction between solder paste and brown oxide solution during the production process of the circuit board, thereby improving the reliability of the circuit board. Furthermore, compared with the existing PCB board laser hole heat dissipation technology, the first heat dissipation layer is filled in the first through hole, the production cycle is short and the hole wall quality is more stable.

[0043] Optionally, the material of the first filling portion 401 is the same as that of the first heat dissipation layer 701 .

[0044] Specifically, the materials of the first filling part 401 and the first heat dissipation layer 701 are both heat dissipation conductive materials, and the heat dissipation conductive materials can be a high molecular conductive thermal conductive polymer, and the high molecular conductive thermal conductive polymer can include at least one of gold, silver and graphite. Exemplarily, the materials of the first filling part 401 and the first heat dissipation layer 701 are both high molecular conductive thermal conductive polymers including three materials of gold, silver and graphite, and the materials of the first filling part 401 and the materials of the first heat dissipation layer 701 have the same proportion of the three materials of gold, silver and graphite, so that the conductivity and heat dissipation of the materials are the same, which enhances the stability of conduction between the first functional device 301 and the first circuit layer 501, makes the heat conduction more uniform, and improves the heat dissipation efficiency.

[0045] The material of the first filling part 401 may be different from the material of the first heat dissipation layer 701. For example, the material of the first filling part 401 needs to fix the first functional device 301, so it needs strong adhesion. The proportion of graphite in the heat dissipation conductive material can be appropriately increased according to actual production needs. The first heat dissipation layer 701 needs to have high thermal conductivity, electrical conductivity, anti-oxidation and anti-hygroscopic properties. The proportion of gold elements in the heat dissipation conductive material can be adjusted according to actual conditions.

[0046] In the embodiment of the present invention, by setting the material of the first filling part 401 to be the same as the material of the first heat dissipation layer 701, the conductivity and heat dissipation of the heat dissipation conductive material are made the same. On the one hand, the stability of conduction between the first functional device and the first circuit layer can be improved. On the other hand, the heat conduction between the first filling part and the first heat dissipation layer is made more uniform, which improves the heat dissipation efficiency.

[0047] Figure 2 is a schematic diagram of a second circuit board structure provided according to an embodiment of the present invention. Figure 2The optional circuit board also includes a second circuit layer 801 , which is located on a side of the first core board 101 away from the first circuit layer 501 and is insulated from the first core board 101 .

[0048] Specifically, Figure 2 As shown, the second circuit layer 801 may be a PCB board, an insulating layer is provided between the second circuit layer 801 and the first core board 101, and the insulating layer may be a prepreg. The second circuit layer 801 is the power side of the circuit board, and is usually used to release signals.

[0049] The optional first through hole 601 includes a top opening away from the first core plate 101 and a bottom opening close to the first core plate 101 ; along the direction from the top opening to the bottom opening, the aperture of the first through hole 601 gradually decreases.

[0050] Specifically, the first through hole 601 may be a laser hole, which is a hole formed by irradiating the surface of a material with a high-energy-density laser beam to rapidly vaporize or melt the material. Due to the heat and light diffraction effect generated by the interaction between the laser and the material of the first circuit layer 501, the material removal range at the top opening of the first through hole 601 is relatively wide, and as the laser penetrates deeper, the energy is more concentrated, and the removal range gradually narrows, so the aperture of the first through hole 601 gradually decreases in the direction from the top opening to the bottom opening.

[0051] Figure 3 is a schematic diagram of a third circuit board structure provided according to an embodiment of the present invention; Figure 4 is a schematic diagram of a fourth circuit board structure provided according to an embodiment of the present invention. Figure 3 and Figure 4 , the first circuit layer 501 has a plurality of first through holes 601; the sizes of the top openings of at least two of the first through holes 601 are different, or the sizes of the bottom openings of at least two of the first through holes 601 are different.

[0052] Specifically, in the first case, the top opening sizes of the two first through holes 601 are different, such as Figure 3 and Figure 4 As shown, the top opening sizes of the first through hole 601 and the first through hole 602 are different, and the top opening sizes of the first through hole 603 and the first through hole 602 are different. Figure 3 As shown, the top opening size of the first through hole 601 and the first through hole 603 is larger than the top opening size of the first through hole 602. Figure 4 As shown, the top opening size of the first through hole 601 and the first through hole 603 is smaller than the top opening size of the first through hole 602 .

[0053] In the second case, the bottom opening sizes of the two first through holes 601 are different, such as Figure 3 and Figure 4As shown, the bottom opening sizes of the first through hole 601 and the first through hole 602 are different, and the bottom opening sizes of the first through hole 603 and the first through hole 602 are different. Figure 3 As shown, the bottom opening size of the first through hole 601 and the first through hole 603 is larger than the bottom opening size of the first through hole 602. Figure 4 As shown, the bottom opening size of the first through hole 601 and the first through hole 603 is smaller than the bottom opening size of the first through hole 602 .

[0054] In the third case, the top opening sizes of the two first through holes 601 are different and the bottom opening sizes of the two first through holes 601 are different. Figure 3 and Figure 4 As shown, the top opening size and the bottom opening size of the first through hole 601 and the first through hole 602 are different, and the top opening size and the bottom opening size of the first through hole 603 and the first through hole 602 are different. Figure 3 As shown, the top opening size of the first through hole 601 and the first through hole 603 is larger than the top opening size of the first through hole 602, and the bottom opening size of the first through hole 601 and the first through hole 603 is larger than the bottom opening size of the first through hole 602. This arrangement allows the first through hole 601 and the first through hole 603 to be filled with more heat dissipation conductive material, and the heat dissipation effect is better, thereby enhancing the heat dissipation effect at both ends of the first functional device 301 and further improving the heat dissipation efficiency. Figure 4 As shown, the top opening size of the first through hole 601 and the first through hole 603 is smaller than the top opening size of the first through hole 602, and the bottom opening size of the first through hole 601 and the first through hole 603 is smaller than the bottom opening size of the first through hole 602. This arrangement allows the first through hole 602 to be filled with more heat dissipation conductive material, thereby enhancing the heat dissipation effect of the central part of the first functional device 301 and further improving the heat dissipation efficiency.

[0055] Optional References Figure 1 The top opening size and the bottom opening size of the three first through holes 601 are set to be the same. This setting can make the heat dissipation effect of the three first through holes 601 the same, achieve uniform heat dissipation, and further improve the heat dissipation efficiency.

[0056] Optional References Figure 1 The first functional device is accommodated in the first groove, and the gap between the groove wall of the first groove 201 and the corresponding side of the first functional device 301 is Wa, 0.1mm≤Wa≤0.3mm.

[0057] Specifically, the size of the first groove 201 needs to be set according to the size of the first functional device 301. Usually, the gap Wa between the groove wall of the first groove 201 and the corresponding side of the first functional device 301 is in the range of 0.1mm≤Wa≤0.3mm to facilitate the placement of the first functional device 301.

[0058] In addition, it should be noted that since there is a gap between the groove wall of the first groove 201 and one side of the corresponding first functional device 301, when the heat dissipation conductive material is filled in the first groove 201, the heat dissipation conductive material will flow into the gap, thereby making the bonding between the first functional device 301 and the first core board 101 more firmly.

[0059] The surface flatness of the optional heat dissipation film layer 701 is less than 0.2 mm.

[0060] Specifically, the heat dissipation film layer 701 is a uniform heat dissipation layer formed by evenly applying heat dissipation conductive material on the first circuit layer 501 and baking it. The heat dissipation film layer 701 formed in this way has anti-oxidation and anti-hygroscopic properties and its surface flatness is less than 0.2mm.

[0061] Based on the above inventive concept, an embodiment of the present invention further provides a method for preparing a circuit board. Figure 5 is a schematic flow chart of a method for preparing a circuit board according to an embodiment of the present invention, such as Figure 5 As shown, the method for preparing the circuit board includes:

[0062] S110 , providing a first core plate having a first groove penetrating the first core plate.

[0063] S120, placing a first functional device in the first groove, and filling the first groove with a heat dissipation conductive material to form a first filling portion.

[0064] S130, forming a first circuit layer on the first core board and forming a first through hole on the first circuit layer.

[0065] S140, forming a first heat dissipation layer on the first circuit layer, wherein the first heat dissipation layer contacts the first filling portion through the first through hole; the material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

[0066] The preparation method can be applied to manufacture the circuit board described in any of the above embodiments.

[0067] In the embodiment of the present invention, a through-type first groove is opened on the first core board, a first functional device is placed in the first groove, and the first groove is filled with a heat dissipation conductive material to form a first filling portion 401, and then a first circuit layer is formed on the first core board and a first through hole is formed on the first circuit layer, and a first heat dissipation layer is further formed on the first circuit layer, and the first heat dissipation layer contacts the first filling portion 401 through the first through hole, wherein the material of the first filling portion 401 and the material of the first heat dissipation layer both include heat dissipation conductive material. The circuit board manufactured by the above technical solution satisfies the heat dissipation of the first functional device while connecting the first functional device with the first circuit layer.

[0068] The following will be described through a specific preparation scheme. Figure 5 The preparation method shown is described in detail. Figure 6 FIG. 1 is a process flow chart of a method for preparing a circuit board according to an embodiment of the present invention. Figure 6 As shown, the preparation method comprises:

[0069] S110 , providing a first core plate having a first groove penetrating the first core plate.

[0070] Specifically, the first core board 101 may be an inner core board of a printed circuit board (PCB). A through first groove 201 is formed on the first core board 101 by a CNC process, wherein the CNC process is computer digital controlled precision machining, which is a technology for controlling a machine tool machining process by computer programming.

[0071] S120, placing a first functional device in the first groove, and filling the first groove with a heat dissipation conductive material to form a first filling portion.

[0072] Specifically, the size Wa of the first groove 201 needs to meet the placement requirements of the first functional device 301, and the gap between the groove wall of the first groove 201 and the corresponding side of the first functional device 301 is Wa, 0.1mm≤Wa≤0.3mm. Among them, the first functional device 301 includes semiconductor components, capacitors, magnetic cores and other components or combined components. Before placing the first functional device 301 in the first groove 201, the first surface 111 of the inner core plate 101 needs to be fixed on the temporary carrier 901 using a seamless bonding method such as vacuum adsorption. After placing the first functional device 301, the conductive heat dissipation material is evenly and evenly applied to the groove through a printing process, and a first filling part 401 with good conductive and thermal conductivity is formed after baking. The material of the temporary carrier 901 is a material with a flat, smooth, clean and anti-static surface. The heat dissipation conductive material can be a high molecular conductive and thermally conductive polymer, and this high molecular conductive and thermally conductive polymer can include at least one of gold, silver and graphite. In addition, the heat dissipation conductive material is a colloidal liquid material. The existing solution of fixing functional devices by solder paste usually requires pre-browning of the functional devices and the PCB board to increase the bonding force between the functional devices and the PCB board, while the heat dissipation conductive material used in the present invention has a strong bonding force and does not require pre-browning of the functional devices and the PCB board. In addition, when the functional devices and the PCB board are subjected to the browning treatment during the subsequent pressing process, the heat dissipation conductive material will not chemically react with the browning solution. Based on this, the use of heat dissipation conductive material to replace the solder paste in the prior art to fix the functional devices can, on the one hand, shorten the production cycle and save costs, and on the other hand, avoid the chemical reaction between the solder paste and the browning solution, thereby improving the reliability of the circuit board.

[0073] S130, forming a first circuit layer on the first core board and forming a first through hole on the first circuit layer.

[0074] Optionally, a second circuit layer 801 may be formed on a side of the first core board 101 that is away from the first circuit layer 501 .

[0075] Specifically, the first core board 101 with the first functional device 301 is combined with the first circuit layer 501 and the second circuit layer 801 through a lamination process and an insulating layer. The first circuit layer 501 and the second circuit layer 801 are PCB boards. The first functional device 301 is embedded in the PCB. The insulating layer material includes a prepreg, which is mainly composed of resin and reinforcing material. After the lamination is completed, a first through hole 601 is made on the first circuit layer by a laser processing process. Laser processing, also known as laser processing, is a technology that uses a high-energy-density light beam to irradiate the surface of a material to vaporize or change the color of the material. Then, a printed resin plugging process is used to fill the conductive heat dissipation material into the first through hole 601. The printed resin plugging process is a process for improving the electrical performance and reliability of a PCB board. The present invention uses this process to fill the conductive heat dissipation material into the first through hole 601 to achieve conduction between layers. The present invention adopts the above scheme to form the first through hole 601, which can ensure the conduction between the first functional device 301 and the first circuit layer 501 while ensuring the heat dissipation of the first functional device 301. In order to connect the functional device with the outer layer board, the inner wall of the hole needs to be first electroplated with copper and then electroplated with copper. This process takes a long time and takes more than eight hours. If there is a mistake in the electroplating process, the chip will be scrapped and resources will be wasted. The present invention can save a lot of time by using the resin plugging process in just four hours. If there is a problem with the filling quality during the filling process, the hole can be cavitated by chemical agents and the filling can be repeated, so that the chip will not be scrapped and the cost will be saved. In addition, the hole filling may be incomplete during the electroplating copper process, and the present invention can use heat dissipation conductive material to fill the hole repeatedly to avoid such problems. Thereby further improving the reliability of the circuit board.

[0076] S140, forming a first heat dissipation layer on the first circuit layer, wherein the first heat dissipation layer contacts the first filling portion through the first through hole; the material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

[0077] Specifically, a printing process is used on the first circuit layer 501 to evenly spread the heat dissipation conductive material on the surface of the first circuit layer 501, and a heat dissipation film is formed after baking and curing. The heat dissipation film layer 701 formed in this way has anti-oxidation and anti-hygroscopic properties, and its surface flatness is less than 0.2mm.

[0078] In the embodiment of the present invention, a through-type first groove is opened on the first core board, a first functional device is placed in the first groove, and the first groove is filled with a heat-dissipating conductive material to form a first filling portion, and then a first circuit layer is formed on the first core board and a first through hole is formed on the first circuit layer, and a first heat dissipation layer is further formed on the first circuit layer, and the first heat dissipation layer contacts the first filling portion through the first through hole, wherein the material of the first filling portion and the material of the first heat dissipation layer both include heat-dissipating conductive material. The circuit board manufactured by the above technical solution satisfies the heat dissipation of the first functional device while connecting the first functional device to the first circuit layer. In addition, by fixing the first functional device with heat-dissipating conductive material instead of solder paste, the reaction between solder paste and brown oxide solution can be avoided during the manufacturing process of the circuit board, thereby improving the reliability of the circuit board. Furthermore, compared with the existing PCB board laser hole heat dissipation technology, the first heat dissipation layer is filled in the first through hole, the manufacturing cycle is short and the hole wall quality is more stable.

[0079] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0080] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A circuit board, characterized in that: include: A first core plate having a first groove penetrating through the first core plate; a first functional device accommodated in the first groove and a first filling portion filled in the first groove; A first circuit layer insulated from the first core board, the first filling portion is located between the first functional device and the first circuit layer, the first circuit layer has at least one first through hole, the first groove covers the first through hole in a first direction, and the first direction is perpendicular to the first circuit layer; A first heat dissipation layer is located on a side of the first circuit layer away from the first core board, and the first heat dissipation layer is also filled in the first through hole and in contact with the first filling portion; The material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

2. The circuit board according to claim 1, characterized in that: The material of the first filling portion is the same as that of the first heat dissipation layer.

3. The circuit board according to claim 1, characterized in that: The heat dissipation conductive material includes at least one of gold, silver and graphite.

4. The circuit board according to claim 1, characterized in that: Also includes: The second circuit layer is located on a side of the first core board away from the first circuit layer and is insulated from the first core board.

5. The circuit board according to claim 1, characterized in that: The first through hole includes a top opening away from the first core plate and a bottom opening close to the first core plate; Along the direction from the top opening to the bottom opening, the aperture of the first through hole gradually decreases.

6. The circuit board according to claim 5, characterized in that: The first circuit layer has a plurality of the first through holes; The sizes of top openings of at least two of the first through holes are different, or the sizes of bottom openings of at least two of the first through holes are different.

7. The circuit board according to claim 1, characterized in that: The first functional component is accommodated in the first groove, and a gap between a groove wall of the first groove and a corresponding side of the first functional component is Wa, 0.1 mm≤Wa≤0.3 mm.

8. The circuit board according to claim 2, characterized in that: The surface flatness of the heat dissipation film layer is less than 0.2 mm.

9. A method for preparing a circuit board, used for preparing the circuit board according to any one of claims 1 to 8, characterized in that: The preparation method comprises: Providing a first core plate having a first groove extending through the first core plate; Placing a first functional device in the first groove, and filling the first groove with a heat dissipation conductive material to form a first filling portion; forming a first circuit layer on the first core board and forming a first through hole on the first circuit layer; forming a first heat dissipation layer on the first circuit layer, wherein the first heat dissipation layer contacts the first filling portion through the first through hole; The material of the first filling portion and the material of the first heat dissipation layer both include heat dissipation conductive material.

10. The preparation method according to claim 9, characterized in that: Also includes: A second circuit layer is formed on a side of the first core board away from the first circuit layer.

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