Circuit board and manufacturing method thereof
By laying electrical layers on the ceramic substrate of the circuit board and welding metal plates, combined with the method of pressing the second substrate, the problem of insufficient warping and heat dissipation capabilities of the circuit board during the manufacturing process is solved, and high-density layout and good heat dissipation are achieved performance.
Patent Information
- Application Number
- CN202411714974.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-02-18
AI Technical Summary
Existing circuit boards are prone to warping during manufacturing, and have insufficient heat dissipation capabilities, making it difficult to meet the needs of high device density and good heat dissipation.
By laying a first electrical layer on the ceramic substrate and welding the metal plate by the active metal brazing method, the metal plate can be separated into the grooves pre-opened by the core plate, and then pressing the second substrate on the core plate to ensure electrical power The layers are connected and tightly combined to avoid warping and improve heat dissipation performance through the metal plate as the heat dissipation surface.
It realizes the high-density layout and good heat dissipation performance of the circuit board, avoids warping problems during the pressing process, and ensures the flatness and efficient heat dissipation of the circuit board.
Smart Images
Figure CN119485934A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a circuit board and a manufacturing method thereof, belonging to the technical field of circuit board process optimization. Background Art
[0002] Electronic products represented by inverters, on-board chargers and converters have put forward higher requirements on the device density and heat dissipation capacity of circuit boards. Existing circuit boards embed the electrical layer including power devices into the circuit board in an embedded manner. During the multi-layer basic lamination process, warping problems will occur due to the uneven distribution of devices in the electrical layer.
[0003] Therefore, the existing circuit board manufacturing method has the problem that the circuit board has poor heat dissipation capacity and is prone to warping during the pressing step in the manufacturing process. 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 with strong heat dissipation capability and which avoids warping during the pressing process, 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 first electrical layer is arranged on one side of the ceramic substrate, and a metal plate is welded on the other side by active metal brazing; The metal plate is detachably embedded in the groove pre-opened in the core plate; Laminating at least one second substrate on the core substrate, wherein the electrical layer of the second substrate is connected to the first electrical layer; The metal plate is taken out from the groove to obtain a manufactured circuit board.
[0006] In some embodiments of the first aspect, a target point is pre-opened on the ceramic substrate; The step of laminating at least one second substrate on the core board comprises: covering the core board with a second prepreg, and covering the second copper layer on the second prepreg; Opening a window in the second copper layer, wherein the window corresponds to the position of the target point; Opening a through hole in the second prepreg according to the positioning of the target point; A second copper layer is plated on the through hole, and a second electrical layer is engraved on the second copper layer, so that the second electrical layer is connected to the first electrical layer through the through hole.
[0007] In some embodiments of the first aspect, the first electrical layer includes a chip, and when the metal plate is detachably embedded in a groove pre-opened in the core plate, the chip is controlled to be flush with the core plate in height; The method of laminating at least one second substrate on the core substrate also includes: The cavities between adjacent chips and between the chip and the core board are filled by the first prepreg.
[0008] In some embodiments of the first aspect, the detachably embedding the metal plate into a groove pre-opened in the core plate comprises: Covering the bottom of the groove with a release film; The metal plate is embedded in the groove and simultaneously attached to the release film.
[0009] In some embodiments of the first aspect, a first to-be-separated board is obtained after at least one layer of the second substrate is pressed onto the core board; The step of taking the metal plate out of the groove to obtain a manufactured circuit board comprises: Cutting the first to-be-separated board along the edge of the groove to obtain a second to-be-separated board; The release film on the second plate to be separated is torn off to obtain a manufactured circuit board.
[0010] In some embodiments of the first aspect, a thermal interface material is pre-disposed on a side of the metal plate facing away from the ceramic substrate; After the metal plate is taken out from the groove, a heat sink is welded on the surface of the thermal interface material.
[0011] In the second aspect, the present application also provides a circuit board, including a metal plate, one side of the metal plate is used to connect to a heat sink, and the other side is welded to a ceramic substrate by active metal brazing; a first electrical layer is provided on the surface of the ceramic substrate, and at least one second substrate is pressed onto the surface of the first electrical layer.
[0012] In some embodiments of the second aspect, a thermal interface material is disposed on the surface of the metal plate, and the heat sink is welded to the surface of the thermal interface material.
[0013] In some embodiments of the second aspect, the metal plate is a copper plate, and the material of the ceramic part of the ceramic substrate is aluminum nitride.
[0014] Compared with the prior art, the present invention has the following beneficial effects: The manufacturing method of the circuit board provided in the present application utilizes the ability of the metal plate not to be easily deformed, and uses the metal plate as a force support to avoid deformation and warping of the circuit board during the pressing process. In order to better combine with the metal plate, the first electrical layer is selected to be arranged on the ceramic substrate, and the ceramic substrate and the metal plate are welded by an active metal brazing method, so that the ceramic substrate and the metal plate are tightly connected; when the circuit board is working, it can rely on the metal plate to absorb the heat generated by the first electrical layer and other electrical layers, and using the metal plate as the heat dissipation surface can greatly improve the heat dissipation performance of the circuit board; the circuit board provided in the present application has good heat dissipation performance, the metal plate and the ceramic substrate are tightly connected, and based on the supporting role of the metal plate, the flatness is high and there is almost no warping caused by the pressing process. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] 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.
[0016] Figure 1 It is a top view schematic diagram of a core board provided in the method for manufacturing a circuit board provided in this embodiment in which a groove is formed; Figure 2 yes Figure 1 A schematic top view of using a release film to cover the bottom of the groove; Figure 3 yes Figure 2 A top view schematic diagram of a functional module embedded in a groove; Figure 4 yes Figure 3 A schematic top view of the first layer of the second substrate being pressed onto the core substrate; Figure 5 yes Figure 4 A top view schematic diagram of a window opened on the second copper layer corresponding to the target position; Figure 6 yes Figure 5 A top view schematic diagram of opening a through hole on the second copper layer; Figure 7 is a schematic top view of a functional module in the method for manufacturing a circuit board provided in this embodiment; Figure 8 is a cross-sectional view of a functional module in the method for manufacturing a circuit board provided in this embodiment; Fig. 9 After the first layer and the second substrate are pressed on the core board Figure 8 Cross-sectional view of the functional module; Fig.10 yes Fig. 9A cross-sectional view of the first plate to be separated obtained after the second substrate is pressed; Fig.11 is along Fig. 9 A cross-sectional view of the second plate to be separated cut along the longitudinal cutting path; Fig.12 yes Fig.11 A cross-sectional view of the manufactured circuit board obtained by tearing off the release film of the second plate to be separated; Fig.13 yes Fig.12 A cross-sectional view of welding a heat sink on a metal plate of a manufactured circuit board; Fig.14 is a flowchart of the steps of the method for manufacturing a circuit board provided in this embodiment; In the figure: 1. core board; 2. groove; 3. functional module; 4. manufactured circuit board; 5. window; 6. first prepreg; 7. second copper layer; 8. release film; 9. second prepreg; 10. metal plate; 11. ceramic substrate; 12. first electrical layer; 13. chip; 14. target; 15. through hole; 16. first board to be separated; 17. longitudinal cutting path; 18. second board to be separated; 19. thermal interface material; 20. heat sink; 21. second substrate. DETAILED DESCRIPTION
[0017] 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
[0018] This embodiment provides a method for manufacturing a circuit board. Fig.14 The manufacturing method of the circuit board provided in this embodiment includes: refer to Figure 8 , a first electrical layer 12 is arranged on one side of a ceramic substrate 11, and a metal plate 10 is welded on the other side by an active metal brazing method, referring to Figure 7 and Figure 8 , just for the convenience of description, the combination of the metal plate 10-ceramic substrate 11-first electrical layer 12 is called a functional module 3, and the functional module 3 is based on the ceramic substrate 11, one side is the metal plate 10 for heat dissipation and deformation control, and the other side is the first electrical layer 12 that performs the corresponding function; refer to Figure 1 , Figure 3 and Figure 7, the metal plate 10 is detachably embedded in the groove 2 pre-opened in the core plate 1, that is, the functional module 3 is embedded (including semi-embedded and fully embedded) in the core plate 1. The core plate 1 as a fixture will help to fix the position of the functional module 3. At the same time, the core plate 1 will be well combined with the resin and cured sheet materials of the second substrate 21 in the following to overcome the problem of the ceramic substrate 11 and the Fig.10 The problem of poor bonding performance when the second substrate 21 is pressed.
[0019] According to design requirements, one or more layers of the second substrate 21 are pressed onto the core board 1, wherein the electrical layer of the second substrate 21 is connected to the first electrical layer 12; during the pressing process, the metal plate 10 itself is not easily deformed, and the deformation and warping of the functional module 3 and the second substrate 21 pressed thereon can be controlled.
[0020] In order to control the deformation of the circuit board during the pressing process, the present embodiment selects the metal plate 10 as the substrate. In order to perform active metal brazing with the metal plate 10, the first electrical layer 12 is selected to be arranged on the ceramic substrate 11. However, the bonding performance between the ceramic substrate 11 and the nearest second substrate 21 is poor. In order to overcome this problem, the functional module 3 is embedded in the core board 1 and then pressed. The resin-like material of the second substrate 21 can be effectively fixed to the core board 1, thereby ensuring that the ceramic substrate 11 and the nearest second substrate 21 are tightly bonded to each other during the production process of the circuit board.
[0021] refer to Fig.12 Finally, the metal plate 10 is taken out from the groove 2 to obtain the manufactured circuit board 4. The manufactured circuit board 4 obtained finally has a complete appearance without warping edges, and the metal plate 10 can absorb the heat of the first electrical layer 12 when it is working, thereby improving the heat dissipation performance.
[0022] In summary, the manufacturing method of the circuit board provided in this embodiment utilizes the ability of the metal plate 10 to be not easily deformed, and uses the metal plate 10 as a force support to avoid deformation and warping of the circuit board during the pressing process. In order to better combine with the metal plate 10, the first electrical layer 12 is selected to be arranged on the ceramic substrate 11, and the ceramic substrate 11 and the metal plate 10 are welded by active metal brazing method, so that the ceramic substrate 11 and the metal plate 10 are tightly connected; when the circuit board is working, it can rely on the metal plate 10 to absorb the heat generated by the first electrical layer 12 and other electrical layers, and using the metal plate 10 as the heat dissipation surface can greatly improve the heat dissipation performance of the circuit board. Embodiment 2
[0023] 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.
[0024] refer to Figure 7 and Figure 8 In this embodiment, the first electrical layer 12 of a single functional module 3 includes not only circuits but also a plurality of chips 13 , and a plurality of target points 14 are arranged on the ceramic substrate 11 for positioning when etching the nearest second substrate 21 .
[0025] refer to Figure 1 As one of the embodiments, the groove 2 pre-opened in the core board 1 is a through groove, and the thickness of the core board 1 is designed to be the same as the thickness of the functional module 3. After the functional module 3 is embedded in the groove 2, the bottom metal plate 10 and the top chip 13 are flush with the two sides of the core board 1 respectively to prevent depression during the pressing process.
[0026] In order to improve the production efficiency, a plurality of grooves 2 may be pre-opened in the core board 1, and a plurality of circuit boards may be produced at the same time.
[0027] Generally speaking, the functional module 3 can be fixed to the core board 1 by glue, but in order to prevent glue overflow during the pressing process, this embodiment does not use glue for fixing. Figure 2 As one embodiment, a release film 8 is attached to the bottom side of the core board 1, and then the functional module 3 is embedded in the groove 2, and the metal plate 10 is attached to the release film 8, which is equivalent to the functional module 3 and the core board 1 are not directly connected to each other, but are attached to the release film 8 at the same time to indirectly keep the position fixed. The effect can be referred to Figure 3 and Fig. 9 .
[0028] refer to Figure 7 and Figure 8 If the area of the core board 1 is much smaller than the area of the first electrical layer 12, cavities will be formed between adjacent chips 13 and between the chip 13 and the edge of the groove 2 during the pressing process, and the second substrate 21 will easily collapse. Fig. 9 A first semi-cured sheet 6 is embedded between adjacent chips 13 and between the chip 13 and the core board 1. The first semi-cured sheet 6 is used to fill the cavity, compensate for the height difference between the first electrical layer 12 / ceramic substrate 11 and the surrounding chips 13 and the core board 1, and prevent excessive collapse during the pressing process.
[0029] After the cavity is filled, the first layer of the second substrate 21 can be pressed, see Fig. 9, the first layer second substrate 21 is pressed onto the plane formed by the core board 1, the chip 13 and the first prepreg 6. The second prepreg 9 of the second substrate 21 and the first prepreg 6 have similar material properties and are therefore very tightly connected, but the first prepreg 6 and the ceramic substrate 11 exposed in the line gap of the first electrical layer 12 may be poorly connected. It is worth noting that the second prepreg 9 and the core board 1 have a good connection tightness, which can effectively compensate for the poor tightness between the first prepreg 6 and the ceramic substrate 11, ensuring the structural stability of the assembly after pressing, and preventing the second substrate 21 from falling off from the functional module 3.
[0030] refer to Fig. 9 After the first layer of the second substrate 21 is pressed, the pattern of the first layer of the second substrate 21 is etched. Figure 4 The second prepreg 9 has a second copper layer 7 on the side facing away from the first electrical layer 12. Figure 5 , roughly find the position of the target point 14 and open the window. The area of the window 5 is larger than the target point 14. Due to the semi-transparent nature of the prepreg, the target point 14 can be located through the window 5. According to the positioning of the target point 14, refer to Figure 6 , corresponding through holes 15 are opened. For example, in this embodiment, the chip 13 has multiple contacts, through holes 15 connecting the contacts of the chip 13 are opened on the second prepreg 9 by laser, and the through holes 15 are copper plated and the circuit is etched on the second copper layer 7 to produce the second electrical layer, so as to realize the circuit connection between the second electrical layer and the first electrical layer 12.
[0031] After the first layer second substrate 21 is pressed and the second electrical layer is made and connected to the first electrical layer 12, the reference Fig.10 , press the other layers of second substrates 21 onto the first layer of second substrate 21 according to conventional methods.
[0032] refer to Fig.10 After multiple pressings, the first to-be-separated plate 16 is obtained, the second substrate 21 and the core plate 1 are in a combined state, and the ceramic substrate 11 may also adhere to the core plate 1 on the side. Fig.10 The longitudinal cutting path 17 shown cuts the first to-be-separated plate 16, and the longitudinal cutting path 17 is arranged along the edge of the groove 2 to obtain Fig.11 The second plate to be separated 18 is shown, and the release film 8 on the second plate to be separated 18 is torn off to obtain Fig.11 The manufactured circuit board 4 is shown. It is worth noting that after the release film 8 is torn off, the edge of the circuit board should be properly insulated and reinforced to reduce the probability of separation of the ceramic substrate 11 and the first prepreg 6.
[0033] refer to Fig.13As one of the embodiments, a thermal interface material 19 is pre-arranged on the side of the metal plate 10 facing away from the ceramic substrate 11. After the metal plate 10 is taken out of the groove 2, a heat sink 20 is welded on the surface of the thermal interface material 19, which will enable the manufactured circuit board 4 to have excellent heat dissipation performance.
[0034] As one embodiment, the metal plate 10 is a copper plate, and the material of the ceramic part of the ceramic substrate 11 is aluminum nitride. The active metal brazing method between copper and aluminum nitride has good welding performance. Embodiment 3
[0035] This embodiment provides a circuit board, which can be manufactured by the manufacturing method provided in the first or second embodiment. Fig.12 The circuit board provided in this embodiment includes a metal plate 10, one side of the metal plate 10 is used to connect with the heat sink 20, and the other side is welded to a ceramic substrate 11 by active metal brazing method; a first electrical layer 12 is provided on the surface of the ceramic substrate 11, and at least one second substrate 21 is pressed on the surface of the first electrical layer 12.
[0036] refer to Fig.13 As one embodiment, a thermal interface material 19 is disposed on the surface of the metal plate 10 , and a heat sink 20 is welded on the surface of the thermal interface material 19 .
[0037] As one embodiment, the metal plate 10 is a copper plate, and the material of the ceramic part of the ceramic substrate 11 is aluminum nitride.
[0038] The metal plate 10 can be used for heat dissipation. The circuit board provided in this embodiment has good heat dissipation performance. The metal plate 10 and the ceramic substrate 11 are tightly connected. Based on the supporting effect of the metal plate 10, the flatness is high and there is almost no warping caused by the pressing process. For details, please see Embodiment 1 or 2, and the principle will not be repeated here.
[0039] It is worth noting that Figure 7 and Figure 8 The number and distribution spacing of the chips 13 on the functional modules 3 shown are different, and the purpose is to show that the first electrical layers 12 of the functional modules 3 with different functions are different. Figure 7 and Figure 8 There is no direct top view to side view relationship.
[0040] 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.
[0041] 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".
[0042] 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, A first electrical layer (12) is arranged on one side of a ceramic substrate (11), and a metal plate (10) is welded to the other side by an active metal brazing method; The metal plate (10) is detachably embedded in a groove (2) pre-opened in the core plate (1); Laminating at least one layer of a second substrate (21) on the core board (1), wherein the electrical layer of the second substrate (21) is connected to the first electrical layer (12); The metal plate (10) is taken out from the groove (2) to obtain a manufactured circuit board (4).
2. The method for manufacturing a circuit board according to claim 1, characterized in that a target point (14) is pre-opened on the ceramic substrate (11); The laminating of at least one layer of the second substrate (21) on the core board (1) comprises: covering the core board (1) with a second prepreg (9), and covering the second copper layer (7) on the second prepreg (9); Opening a window in the second copper layer (7), the window (5) corresponding to the position of the target point (14); A through hole (15) is formed in the second prepreg (9) according to the positioning of the target point (14); A second copper layer (7) is plated on the through hole (15), and a second electrical layer is engraved on the second copper layer (7), so that the second electrical layer is connected to the first electrical layer (12) through the through hole (15).
3. The method for manufacturing a circuit board according to claim 2, wherein: The first electrical layer (12) comprises a chip (13), and when the metal plate (10) is detachably embedded in a groove (2) pre-opened in the core plate (1), the chip (13) is controlled to be flush with the core plate (1); The method of laminating at least one layer of a second substrate (21) on the core plate (1) further comprises: The cavities between adjacent chips (13) and between the chips (13) and the core board (1) are filled by the first prepreg sheet (6).
4. The method for manufacturing a circuit board according to claim 1, wherein: The step of detachably embedding the metal plate (10) into a groove (2) pre-opened in the core plate (1) comprises: Using a release film (8) to cover the bottom of the groove (2); The metal plate (10) is embedded in the groove (2) and simultaneously adhered to the release film (8).
5. The method for manufacturing a circuit board according to claim 4, The method is characterized in that, after at least one layer of the second base plate (21) is pressed onto the core plate (1), a first plate to be separated (16) is obtained; The step of removing the metal plate (10) from the groove (2) to obtain a manufactured circuit board (4) comprises: Cutting the first to-be-separated plate (16) along the edge of the groove (2) to obtain a second to-be-separated plate (18); The release film (8) on the second plate to be separated (18) is torn off to obtain the manufactured circuit board (4).
6. The method for manufacturing a circuit board according to claim 1, wherein: Pre-arranging a thermal interface material (19) on a side of the metal plate (10) facing away from the ceramic substrate (11); After the metal plate (10) is taken out of the groove (2), a heat sink (20) is welded on the surface of the thermal interface material (19).
7. A circuit board, characterized in that: The invention comprises a metal plate (10), one side of the metal plate (10) being used for connecting to a heat sink (20), and the other side being welded to a ceramic substrate (11) by an active metal brazing method; a first electrical layer (12) being provided on the surface of the ceramic substrate (11), and at least one second substrate (21) being pressed onto the surface of the first electrical layer (12).
8. The circuit board according to claim 7, characterized in that: A thermally conductive interface material (19) is disposed on the surface of the metal plate (10), and the heat sink (20) is welded to the surface of the thermally conductive interface material (19).
9. The circuit board according to claim 7, characterized in that: The metal plate (10) is a copper plate, and the material of the ceramic part of the ceramic substrate (11) is aluminum nitride.