Embedded circuit board
By embedding a heat dissipation stepped metal plate onto the resin substrate to form an inlaid structure, the problem of low thermal conductivity of the FR4 substrate is solved, achieving a combination of good heat dissipation performance and low cost, and improving the stability and reliability of the circuit board.
Patent Information
- Application Number
- CN202520135785.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-01-21
AI Technical Summary
The low thermal conductivity of FR4 substrate circuit boards leads to poor heat dissipation in high-power applications, limiting their use in complex circuits and high-power components, while also increasing costs.
An embedded circuit board is designed by embedding a heat dissipation stepped metal plate on a resin substrate to form an embedded structure. The high thermal conductivity of the heat dissipation stepped metal plate is used to compensate for the low thermal conductivity of the resin substrate, thus maintaining the advantage of low cost.
It improves the heat dissipation performance of the circuit board, reduces product costs, ensures the stability and reliability of components, and avoids damage caused by heat accumulation.
Smart Images
Figure CN223899390U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a circuit board, specifically, to an embedded circuit board. Background Technology
[0002] Copper plates exhibit significant advantages in circuit board applications, primarily due to their superior heat dissipation performance. Copper's high thermal conductivity ensures that heat generated by electronic components is rapidly conducted and dissipated, thereby improving product stability and reliability. Furthermore, its strong heat-bearing capacity allows it to withstand high-power operating environments, reducing substrate damage caused by heat buildup.
[0003] In the circuit board industry, FR4 substrate is a common name. It refers to a glass fiber epoxy resin material, specifically a thermosetting plastic composite material formed by glass fiber and epoxy resin. This material is widely used in the electronics and electrical appliance industry, primarily as a substrate material. The "FR" in FR4 is an abbreviation for "flame retardant," indicating that the material has flame-retardant properties, representing a specification where the resin material can self-extinguish when burning. Therefore, FR4 substrate is a substrate material that meets this flame-retardant rating.
[0004] FR4 substrate is a core substrate material for traditional circuit boards, possessing advantages such as high mechanical strength, excellent electrical properties, good flame retardancy, and good processing performance. FR4 substrate is easy to drill, cut, and bend, facilitating multilayer board stacking processes and enabling compact and precise circuit boards. Furthermore, FR4 substrate offers a cost advantage compared to other substrate materials in circuit board applications. However, circuit boards made with FR4 substrate have a significant drawback: low thermal conductivity. This greatly limits the application of FR4 substrate in high-power circuit boards.
[0005] In practical applications of circuit boards, not only are the circuits becoming increasingly complex, but the power of the components is also increasing. To accommodate complex circuit routing and solve the problem of heat dissipation for high power, the use of copper-based substrates is rapidly increasing, but the cost is also rising significantly.
[0006] In view of the above-mentioned problems of the existing technology, there is a need to design a new type of circuit board. Utility Model Content
[0007] The technical problem to be solved by this utility model is to provide an embedded circuit board that can effectively improve the problem of poor heat dissipation of resin substrate circuit boards, thereby improving the heat dissipation level while maintaining the low cost advantage of resin substrate circuit boards.
[0008] To solve the above-mentioned technical problems, this utility model provides an embedded circuit board, which includes a substrate unit and a heat dissipation stepped metal plate. The substrate unit includes a resin substrate and an insulating layer and conductive circuit sequentially stacked on the substrate surface of the resin substrate. The resin substrate is a substrate with a substrate stepped notch and a stepped shape. The heat dissipation stepped metal plate is a metal plate with a metal plate stepped notch. The thin portion of the metal plate of the heat dissipation stepped metal plate extends into the substrate stepped notch, and the thin portion of the resin substrate extends into the metal plate stepped notch, thereby forming a circuit board in which the metal plate stepped notch and the substrate stepped notch are interlocked and connected.
[0009] Typically, the conductive circuit is a copper conductive circuit, the resin substrate is an FR4 substrate, and the heat dissipation step metal plate is a heat dissipation step copper plate.
[0010] Specifically, the insulating layer and conductive circuit are bonded to the upper plane of the substrate to form the substrate unit, and the end face of the insulating layer and conductive circuit facing the heat dissipation step metal plate in the mating direction C is flush with the thin end face of the resin substrate, thereby forming the thin end face of the substrate unit.
[0011] More specifically, the metal plate step notch and the substrate step notch are connected to each other by adhesive bonding, wherein in the fitting direction C, the extension length of the substrate thin portion of the resin substrate is less than the extension length of the metal plate thin portion of the heat dissipation step metal plate, so that when the metal plate step notch and the substrate step notch are connected to each other, there is a gap between the end face of the thin portion of the substrate unit and the vertical face of the notch of the metal plate step notch.
[0012] Specifically, when the notch of the metal plate step and the notch of the substrate step are fitted together, the horizontal surface of the notch of the metal plate step and the horizontal surface of the notch of the substrate step are bonded to each other, and the connecting end face of the thin metal plate in the fitting direction C is bonded to the vertical surface of the notch of the substrate step.
[0013] Specifically, the upper plane of the substrate unit of the substrate unit is flush with the upper plane of the thick part of the heat dissipation step metal plate.
[0014] Specifically, the bottom surface of the thick portion of the resin substrate is flush with the bottom surface of the heat dissipation step metal plate.
[0015] Typically, the upper surface of the thicker portion of the heat dissipation step metal plate is used as a thermal pad.
[0016] Preferably, the thickness A of the thin part of the resin substrate satisfies 0 < A ≤ 0.5 mm, and the sum of the thickness A of the thin part of the substrate and the thickness B of the thin part of the metal plate of the heat dissipation step metal plate is equal to the thickness of the resin substrate.
[0017] Specifically, the thickness A of the thin part of the substrate satisfies 0.1 mm ≤ A ≤ 0.3 mm.
[0018] For the embedded circuit board of the present utility model, since both the resin substrate and the heat dissipation step metal plate are formed in a stepped shape, the metal plate step notch part of the heat dissipation step metal plate and the substrate step notch part of the resin substrate are fitted with each other, so that the heat dissipation step metal plate extends into the resin substrate. In this way, by reasonably designing the matching process structure of the resin substrate and the heat dissipation step metal plate, the high cost of the metal substrate is avoided. At the same time, due to the high thermal conductivity of this embedded heat dissipation step metal plate, the disadvantage of low thermal conductivity of the resin substrate is compensated. The advantages of the metal substrate and the resin substrate are fully combined, so that the cooperation of the two maintains good heat dissipation performance in practical applications while reducing the product cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is a schematic cross-sectional structure view of the embedded circuit board in the specific embodiment of the present utility model;
[0020] Figure 2 is Figure 1 a schematic cross-sectional structure view of the resin substrate in the shown embodiment;
[0021] Figure 3 is Figure 1 a schematic cross-sectional structure view of the resin substrate unit in the shown embodiment, where an insulating layer and a conductive circuit are covered on the resin substrate;
[0022] Figure 4 is Figure 1 a schematic cross-sectional structure view of the heat dissipation step copper plate in the shown embodiment.
[0023] DESCRIPTION OF THE REFERENCE NUMERALS OF THE PRESENT UTILITY MODEL:
[0024] Reference numeral 1 denotes a heat dissipation step metal plate; 1a denotes a thin part of the metal plate
[0025] Reference numeral 1b denotes a thick part of the metal plate; 1c denotes a notch part of the metal plate step
[0026] Reference numeral 1d denotes a vertical surface of the notch part; 1e denotes an upper plane
[0027] Reference numeral 1f denotes a bottom surface; 1g denotes a horizontal plane of the notch part
[0028] Reference numeral 1h denotes a connecting end surface of the thin part of the metal plate; 2 denotes a conductive circuit
[0029] Reference numeral 3 denotes an insulating layer; 4 denotes a resin substrate
[0030] 4a Thick part of substrate 4b Thin part of substrate
[0031] 4c substrate stepped notch portion 4d substrate thin end face
[0032] 4e flat surface on the substrate 4f thick bottom surface of the substrate
[0033] 4g substrate notch horizontal surface; 4h substrate notch vertical surface
[0034] 5-spaced 6-substrate unit
[0035] 6a Upper plane of substrate unit; 6b Thin end face of substrate unit
[0036] A. Substrate thickness B. Metal plate thickness
[0037] C-interlocking direction Detailed Implementation
[0038] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.
[0039] Before describing the specific embodiments of this utility model, it should be noted that although the orientations shown in the illustrations, such as "upper", "lower", and "bottom", are used for ease of description in the following description, although these orientations are the normal orientations of the circuit board, the circuit board of this utility model is not limited to the above orientations during transportation and other conditions. Any technical concept that is substantially equivalent to the above orientations of this utility model shall fall within the protection scope of this utility model.
[0040] See Figures 1 to 4 The embedded circuit board of the basic embodiment of this utility model includes a substrate unit 6 and a heat dissipation stepped metal plate 1. The substrate unit 6 includes a resin substrate 4 and an insulating layer 3 and a conductive circuit 2 sequentially stacked on the substrate upper plane 4e of the resin substrate 4. The resin substrate 4 is a substrate with a substrate stepped notch 4c and a stepped shape. The heat dissipation stepped metal plate 1 is a metal plate with a metal plate stepped notch 1c. The thin metal plate portion 1a of the heat dissipation stepped metal plate 1 extends into the substrate stepped notch 4c, and the thin substrate portion 4b of the resin substrate 4 extends into the metal plate stepped notch 1c, thereby forming a circuit board in which the metal plate stepped notch 1c and the substrate stepped notch 4c are interlocked and connected.
[0041] In the above-described basic embodiment of this utility model, the metal plate step notch 1c of the heat dissipation step metal plate 1 and the substrate step notch 4c of the resin substrate 4 are fitted together, so that the heat dissipation step metal plate 1 extends into the interior of the resin substrate 4. In this way, by rationally designing the matching process structure of the resin substrate 4 and the heat dissipation step metal plate 1, the high cost of the metal substrate is avoided. At the same time, the high thermal conductivity of this embedded heat dissipation step metal plate compensates for the low thermal conductivity of the resin substrate 4. The advantages of the metal substrate and the resin substrate are fully combined, so that the combination of the two maintains good heat dissipation performance in practical applications while reducing product costs.
[0042] Based on the above basic implementation, typically, the conductive circuit 2 can be a copper conductive circuit, the resin substrate 4 can be an FR4 substrate, and the heat dissipation step metal plate 1 can be a heat dissipation step copper plate.
[0043] In terms of specific structure, the insulating layer 3 and the conductive circuit 2 can be bonded to the upper plane 4e of the substrate to form a substrate unit 6, and the end face of the insulating layer 3 and the conductive circuit 2 facing the heat dissipation step metal plate 1 in the mating direction C is flush with the thin end face 4d of the resin substrate 4, thereby forming the thin end face 6b of the substrate unit.
[0044] With the metal plate step notch 1c and the substrate step notch 4c interlocked and connected, the horizontal surface 1g of the notch of the metal plate step notch 1c and the horizontal surface 4g of the substrate notch of the substrate step notch 4c are bonded to each other, and the metal plate thin part 1a connecting end face 1h in the interlocking direction C is bonded to the vertical surface 4h of the substrate notch of the substrate step notch 4c. This interlocking and bonding method makes the resin substrate 4 and the heat dissipation step metal plate 1 more tightly and firmly interlocked, and makes it easier to transfer heat.
[0045] Furthermore, the metal plate step notch 1c and the substrate step notch 4c are connected to each other by adhesive bonding. In the fitting direction C, the extension length of the substrate thin portion 4b of the resin substrate 4 is less than the extension length of the metal plate thin portion 1a of the heat dissipation step metal plate 1. As a result, when the metal plate step notch 1c and the substrate step notch 4c are connected to each other, there is a gap 5 between the end face 6b of the substrate unit thin portion and the vertical face 1d of the notch portion of the metal plate step notch 1c.
[0046] Typically, the upper plane 6a of the substrate unit 6 is flush with the upper plane 1e of the thick portion 1b of the heat dissipation step metal plate 1. Similarly, the bottom surface 4f of the thick portion of the resin substrate 4 is flush with the bottom surface 1f of the heat dissipation step metal plate 1. Furthermore, the upper plane 1e of the thick portion 1b of the heat dissipation step metal plate 1 is generally used as a thermal pad.
[0047] Preferably, the thinner the thickness A of the thin part of the resin substrate 4, the better. Generally, 0 < A ≤ 0.5 mm, and the sum of the thickness A of the thin part of the substrate and the thickness B of the thin part of the metal plate of the heat dissipation step metal plate 1 is equal to the thickness of the resin substrate 4. More preferably, the thickness A of the thin part of the substrate can be 0.1 mm ≤ A ≤ 0.3 mm, which can provide a better heat dissipation effect.
[0048] To help better understand the present invention, the following takes the resin substrate 4 as an FR4 substrate and the heat dissipation step metal plate 1 as a stepped copper plate as an example to further elaborate the present invention.
[0049] That is to say, aiming at the contradiction between heat dissipation and cost of traditional circuit boards, in the present invention, within the same circuit board, a stepped copper plate is nested in the area of the FR4 resin substrate that needs heat dissipation, while the FR4 substrate is used in the circuit area. The copper plate is made into a stepped structure, and the step is nested under the high-heat area of the FR4 substrate. Since the thermal conductivity of the FR4 substrate is low, the thinner the FR4 substrate material in this area, the better. The step size of the stepped copper plate can be designed according to the thermal simulation results in actual applications so that the temperature of the entire circuit board is controlled within the design value.
[0050] See Figure 1 As shown, the upper conductive circuit 2 is a circuit copper foil. Under the circuit copper foil is an insulating layer 3. Under the insulating layer 3 is an FR4 substrate. Under the FR� substrate is a stepped copper plate. The circuit copper foil and the stepped copper plate must be on the same height plane. Among them, at the laminated part of the FR4 substrate and the heat dissipation stepped copper plate, that is, the smaller A is, the better.
[0051] The upper plane of the thick part 1b of the metal plate of the heat dissipation step metal plate 1 is generally used as a welding pad. High heat often generates under the welding pad, especially when the device layout is close. The heat transfer is blocked horizontally, and the main transfer path is vertically. If the vertical transfer is also blocked, the heat continues to concentrate and rise in temperature. After working for a long time, the temperature will exceed the junction temperature of the device and finally the device will be burned out and damaged.
[0052] In the present invention, the heat dissipation metal plate, such as a copper plate, is made into a stepped structure and nested under the FR4 substrate, which can effectively avoid the problem of heat concentration. After the heat passes through the short-range thin part of the FR4 substrate, it quickly dissipates heat through the thin part of the metal plate of the heat dissipation step metal plate 1, making the working environment of the device safer and more reliable.
[0053] The present invention has the following advantages and outstanding effects: First, the heat dissipation step metal plate not only dissipates heat from the welding pad of the device, but also dissipates heat from the conductive circuit in the resin substrate area, avoiding heat concentration in the resin substrate area and burning out the device; Second, since the area of the heat dissipation step metal plate 1 is greatly reduced, the cost of the product has a more significant advantage.
[0054] In general, this invention enables the metal plate step notch 1c of the heat dissipation step metal plate 1 to fit into the substrate step notch 4c of the resin substrate 4, thereby allowing the heat dissipation step metal plate 1 to extend into the resin substrate 4. By rationally designing the mating process structure of the resin substrate 4 and the heat dissipation step metal plate 1, the high cost of the metal substrate is avoided. At the same time, the high thermal conductivity of this embedded heat dissipation step metal plate compensates for the low thermal conductivity of the resin substrate 4. It fully combines the advantages of the metal substrate and the resin substrate, so that the combination of the two maintains good heat dissipation performance in practical applications while reducing product costs.
[0055] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
[0056] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.
[0057] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.
Claims
1. An embedded circuit board, characterized in that, The circuit includes a substrate unit (6) and a heat dissipation stepped metal plate (1). The substrate unit (6) includes a resin substrate (4) and an insulating layer (3) and a conductive circuit (2) sequentially stacked on the substrate upper plane (4e) of the resin substrate (4). The resin substrate (4) is a substrate with a substrate stepped notch (4c) and a stepped shape. The heat dissipation stepped metal plate (1) is a metal plate with a metal plate stepped notch (1c). The thin metal plate portion (1a) of the heat dissipation stepped metal plate (1) extends into the substrate stepped notch (4c), and the thin substrate portion (4b) of the resin substrate (4) extends into the metal plate stepped notch (1c), thereby forming a circuit board in which the metal plate stepped notch (1c) and the substrate stepped notch (4c) are interlocked and connected.
2. The embedded circuit board according to claim 1, characterized in that, The conductive circuit (2) is a copper conductive circuit, the resin substrate (4) is an FR4 substrate, and the heat dissipation step metal plate (1) is a heat dissipation step copper plate.
3. The embedded circuit board according to claim 1, characterized in that, The insulating layer (3) and the conductive circuit (2) are bonded to the upper plane (4e) of the substrate to form the substrate unit (6), and the end face of the insulating layer (3) and the conductive circuit (2) facing the heat dissipation step metal plate (1) in the mating direction C is flush with the thin end face (4d) of the resin substrate (4) to form the thin end face (6b) of the substrate unit.
4. The embedded circuit board according to claim 3, characterized in that, The metal plate step notch (1c) and the substrate step notch (4c) are connected to each other by adhesive bonding. In the fitting direction C, the extension length of the substrate thin portion (4b) of the resin substrate (4) is less than the extension length of the metal plate thin portion (1a) of the heat dissipation step metal plate (1). As a result, when the metal plate step notch (1c) and the substrate step notch (4c) are connected to each other, there is a gap (5) between the end face (6b) of the substrate unit thin portion and the vertical face (1d) of the notch of the metal plate step notch (1c).
5. The embedded circuit board according to claim 4, characterized in that, When the metal plate step notch (1c) and the substrate step notch (4c) are fitted together, the horizontal surface (1g) of the notch of the metal plate step notch (1c) and the horizontal surface (4g) of the substrate notch of the substrate step notch (4c) are bonded together, and the metal plate thin part (1a) on the mating direction C has its metal plate thin part connecting end face (1h) bonded together with the vertical surface (4h) of the substrate notch of the substrate step notch (4c).
6. The embedded circuit board according to claim 4, characterized in that, The upper plane (6a) of the substrate unit (6) is flush with the upper plane (1e) of the thick part (1b) of the heat dissipation step metal plate (1).
7. The embedded circuit board according to claim 4, characterized in that, The bottom surface (4f) of the thick part of the resin substrate (4) is flush with the bottom surface (1f) of the heat dissipation step metal plate (1).
8. The embedded circuit board according to claim 4, characterized in that, The upper plane (1e) of the thick part (1b) of the heat dissipation step metal plate (1) is used as a thermal pad.
9. The embedded circuit board according to any one of claims 1 to 8, characterized in that, The thickness A of the thin substrate portion of the resin substrate (4) satisfies 0 < A ≤ 0.5 mm, and the sum of the thickness A of the thin substrate portion and the thickness B of the thin metal plate portion of the heat dissipation step metal plate (1) is equal to the thickness of the resin substrate (4).
10. The embedded circuit board according to claim 9, characterized in that, The thickness A of the thin substrate portion satisfies 0.1 mm ≤ A ≤ 0.3 mm.