Printed circuit board fully embedded with copper blocks

Abstract

The utility model relates to a printed circuit board fully embedded with copper blocks, which comprises a first base material layer (1) and a second base material layer (2), the first base material layer (1) and the second base material layer (2) are bonded through a prepreg (3), and the upper surface of the first base material layer (1) and the lower surface of the second base material layer (2) are respectively provided with a copper plating layer (4); a copper block (5) is embedded in the printed circuit board, and gaps between the copper block (5) and the first base material layer (1) and between the copper block (5) and the second base material layer (2) are filled with gummosis layers (6) made of the same material as the prepregs (3). Compared with the prior art, the printed circuit board provided by the utility model has the advantages of firm bonding between the copper block and the printed circuit board, good reliability, suitability for large-scale production and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board manufacturing, in particular to a printed circuit board with fully embedded copper blocks. Background Art

[0002] With the development of the size of PCB (Printed Circuit Board) towards miniaturization, the volume of electronic products is getting smaller and the power density is getting larger. How to seek the best methods for heat dissipation and structural design has become a huge challenge in the current electronic industry design. Currently, the commonly used heat dissipation methods generally include making circuit boards with metal substrates and welding metal substrates on circuit boards. However, both of these two processes have the disadvantages of high consumption of metal materials, complex manufacturing processes, high costs, and bulky volumes. For some occasions with relatively low requirements for heat dissipation power, the high processing costs and the complex process of welding metal substrates can no longer meet the market demands.

[0003] Embedded copper block boards are applied in such an environment. An embedded copper block board is a printed circuit board with locally embedded copper blocks. Heat-generating components are directly mounted on the copper blocks, and the heat is conducted out through the copper blocks. Generally, when embedding copper blocks, a groove is dug in the corresponding position on the printed circuit board in advance, and the copper blocks are embedded in the corresponding positions of the grooves. In fact, for the convenience of operation, there is a small gap between the copper blocks and the grooves. When operating, a thermosetting resin material is applied by screen printing method to pre-bond and fix it to fill this gap. After subsequent baking and curing, it can be firmly bonded. A layer of copper conductor is plated on the resin surface through electroless copper plating technology, so that the copper blocks at the grooved positions form an integral body with the printed circuit board.

[0004] However, after screen-printing copper blocks using the existing printing technology, the resin outside the copper blocks is quite different from the printed circuit board material, and the difference in the coefficient of thermal expansion between the two is obvious. During the heating process, it is easy to expand and contract inconsistently in the vertical direction, stretching the conductor to break or forming voids, resulting in potential reliability hazards.

[0005] Therefore, there is still a need to develop a new type of printed circuit board with fully embedded copper blocks. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a printed circuit board with fully embedded copper blocks to overcome the defects of the existing printed circuit boards, such as the unstable combination between the copper blocks and the printed circuit boards and poor reliability.

[0007] The purpose of the utility model can be realized by the following technical solutions:

[0008] A printed circuit board with a fully embedded copper block, the printed circuit board comprising a first base material layer and a second base material layer, the first base material layer and the second base material layer being bonded by a prepreg, and copper plating layers being provided on the upper surface of the first base material layer and the lower surface of the second base material layer;

[0009] The printed circuit board is internally embedded with a copper block, and the gaps between the copper block and the first base material layer and the second base material layer are filled with a flowing glue layer made of the same material as the prepreg.

[0010] Furthermore, a window for embedding the copper block is opened in the printed circuit board.

[0011] Furthermore, the copper block is a cuboid, and the size of the copper block is smaller than the size of the window.

[0012] Furthermore, the single-side length of the copper block is 0.05 - 0.15 mm smaller than the length of the window,

[0013] Furthermore, the single-side width of the copper block is 0.05 - 0.15 mm smaller than the width of the window.

[0014] Furthermore, the height of the copper block is 0 - 0.2 mm smaller than the height of the window.

[0015] Furthermore, the flowing glue layer is the prepreg after melting.

[0016] Furthermore, the copper block does not contact the top of the first base material layer and the bottom of the second base material layer.

[0017] Furthermore, the first base material layer and the second base material layer have the same size.

[0018] Furthermore, the copper plating layer is adapted to the sizes of the first base material layer and the second base material layer.

[0019] Furthermore, the copper plating layer is obtained by electroplating deposition.

[0020] Furthermore, circuit layers are provided on both the first base material layer and the second base material layer.

[0021] Compared with the prior art, the present utility model has the following beneficial effects:

[0022] (1) In the present utility model, the copper block is completely embedded in the printed circuit board through the prepreg and the flowing glue layer made of the same material, so that the copper block and the base material layer become an integral whole, improving the stability and reliability of the combination of the copper block and the printed circuit board.

[0023] (2) The flowing glue formed by melting the prepreg during the lamination process in the present utility model can fill the gaps between the copper block and the upper and lower base material layers to achieve stable adhesion.

[0024] (3) In the present utility model, copper deposition electroplating is carried out on the surface of the base material layer to form a copper layer on the surface. Thus, after the copper block, the surfaces of the first base material layer, the second base material layer, and the prepreg are interconnected together to form a whole, so as to realize the corresponding function of electrical interconnection.

[0025] (4) The printed circuit board of the present utility model is obtained by the method of laminating and fully embedding copper blocks, and the preparation process is simple, which is suitable for the production and manufacturing of large-scale printed circuit boards. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the overall structure of the printed circuit board of the present utility model.

[0027] Figure 2 It is a schematic diagram of the structure before copper plating in Embodiment 3 of the present utility model.

[0028] Explanation of the marks in the figure:

[0029] 1 - First base material layer, 2 - Second base material layer, 3 - Prepreg, 4 - Copper plating layer, 5 - Copper block, 6 - Glue flow layer, 7 - Window, 8 - Excess glue. Detailed Embodiment

[0030] The present utility model will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present utility model, and the detailed implementation manner and specific operation process are given, but the protection scope of the present utility model is not limited to the following embodiments.

[0031] In the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model 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. Therefore, it cannot be understood as a limitation to the present utility model; the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and defined, the terms "installation", "connection", "connection" 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 a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0032] It should be noted that like reference numerals and letters refer to like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] Example 1:

[0034] This example provides a printed circuit board with fully embedded copper blocks. The printed circuit board includes a first base material layer 1 and a second base material layer 2, which are bonded by a prepreg 3 between the first base material layer 1 and the second base material layer 2. Copper plating layers 4 are provided on both the upper surface of the first base material layer 1 and the lower surface of the second base material layer 2.

[0035] A copper block 5 is embedded in the printed circuit board of this example, and the gaps between the copper block 5 and the first base material layer 1 and the second base material layer 2 are filled with a flowable glue layer 6 made of the same material as the prepreg 3.

[0036] Example 2:

[0037] This example provides a printed circuit board with fully embedded copper blocks. The printed circuit board includes a first base material layer 1 and a second base material layer 2, which are bonded by a prepreg 3 between the first base material layer 1 and the second base material layer 2. Copper plating layers 4 are provided on both the outer surfaces of the first base material layer 1 and the second base material layer 2. A copper block 5 is also fully embedded in the printed circuit board, and the copper block 5 does not contact the top of the first base material layer 1 and the bottom of the second base material layer 2.

[0038] The gaps between the copper block 5 and the first base material layer 1 and the second base material layer 2 in this example are filled with a flowable glue layer 6. The flowable glue layer 6 is the prepreg 3 after melting, made of the same material as the prepreg 3, which can improve the firm connection between the printed circuit board and the copper block 5 and enhance the overall reliability.

[0039] A window 7 is provided between the bonded first base material layer 1 and the second base material layer 2 in this example. The copper block 5 is a cuboid, and the size of the copper block 5 is smaller than the size of the window 7. Specifically, the single-side length of the copper block 5 is 0.05 - 0.15 mm smaller than the length of the window 7, the single-side width of the copper block 5 is 0.05 - 0.15 mm smaller than the width of the window 7, and the height of the copper block 5 is 0 - 0.2 mm smaller than the height of the window 7.

[0040] The first base material layer 1 and the second base material layer 2 in this example have the same size, and the copper plating layer 4 is adapted to the sizes of both the first base material layer 1 and the second base material layer 2. Circuit layers are provided on both the first base material layer 1 and the second base material layer 2. The first base material layer 1, the second base material layer 2, and the copper block 5 are laminated to form an integral body, thereby realizing the corresponding function of electrical interconnection.

[0041] Example 3:

[0042] This embodiment provides a printed circuit board with fully embedded copper blocks and a preparation method thereof. The printed circuit board of this embodiment includes a first substrate layer 1, a second substrate layer 2, a prepreg 3, a copper block 5, a glue flow layer 6 between the prepreg 3 and the copper block 5, an overflow glue 8 on the surfaces of the first substrate layer 1, the second substrate layer 2, and the copper block 5, and a copper plating layer 4 formed after electroless copper plating on the surfaces of the first substrate layer 1, the second substrate layer 2, and the copper block 5.

[0043] The preparation method of the printed circuit board of this embodiment specifically includes the following steps:

[0044] S1: Split the printed circuit board into a first substrate layer 1 and a second substrate layer 2, and bond the first substrate layer 1 and the second substrate layer 2 with a prepreg 3.

[0045] S2: Mill a window 7 at the position where the copper block 5 is pre-embedded in the printed circuit board on the first substrate layer 1, the second substrate layer 2, and the prepreg 3.

[0046] S3: Process the copper block 5 according to the position of the milled window 7. The size of the copper block 5 is slightly smaller than the position of the milled window 7. Generally, the length and width dimensions of the copper block 5 are 0.1 - 0.30 mm smaller than the size of the window 7, and the single-side dimension is 0.05 - 0.15 mm smaller. The height of the copper block 5 is 0 - 0.1 mm smaller than the height of the window 7.

[0047] S4: Perform browning treatment on the first substrate layer 1, the second substrate layer 2, and the copper block 5 before lamination.

[0048] S5: Laminate the first substrate layer 1, the second substrate layer 2, the prepreg 3, and the copper block 5 together. The prepreg 3 bonds the first substrate layer 1 and the second substrate layer 2 together. The glue flow layer 6 of the prepreg fills the gaps between the copper block 5 and the first substrate layer 1 and the second substrate layer 2, and bonds the copper block 5 and the first substrate layer 1 and the second substrate layer 2 together to form a whole.

[0049] S6: Part of the prepreg 3 will flow onto the copper block 5 during glue flow, forming an overflow glue 8 (as Figure 2 shown). This part of the overflow glue 8 needs to be ground off to ensure that the surfaces of the first substrate layer 1, the second substrate layer 2, and the copper block 5 are on a flat plane.

[0050] S7: Subsequently, electroplate copper on the surfaces of the first substrate layer 1, the second substrate layer 2, and the copper block 5 to form a copper plating layer 4 on the surface. Thus, the copper block 5, the surfaces of the first substrate layer 1 and the second substrate layer 2, and the prepreg 3 are interconnected to form a whole, realizing the corresponding function of electrical interconnection.

[0051] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the utility model. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the utility model is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the utility model according to the disclosure of the utility model should be within the protection scope of the utility model.

Claims

1. A printed circuit board fully embedded with copper blocks, characterized in that: The printed circuit board comprises a first substrate layer (1) and a second substrate layer (2), the first substrate layer (1) and the second substrate layer (2) are bonded together via a prepreg (3), and a copper plating layer (4) is provided on the upper surface of the first substrate layer (1) and the lower surface of the second substrate layer (2); The printed circuit board is embedded with a copper block (5), and the gaps between the copper block (5) and the first substrate layer (1) and the second substrate layer (2) are filled with a flow adhesive layer (6) made of the same material as the prepreg (3).

2. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: A window (7) for embedding the copper block (5) is provided in the printed circuit board.

3. A printed circuit board fully embedded with copper blocks according to claim 2, characterized in that: The copper block (5) is a rectangular parallelepiped, and the size of the copper block (5) is smaller than the size of the window (7).

4. A printed circuit board fully embedded with copper blocks according to claim 3, characterized in that: The single side length of the copper block (5) is 0.05-0.15 mm smaller than the length of the window (7), and the single side width of the copper block (5) is 0.05-0.15 mm smaller than the width of the window (7).

5. A printed circuit board fully embedded with copper blocks according to claim 3, characterized in that: The height of the copper block (5) is 0-0.2 mm smaller than the height of the window (7).

6. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: The adhesive layer (6) is the melted prepreg (3).

7. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: The copper block (5) is not in contact with the top of the first substrate layer (1) and the bottom of the second substrate layer (2).

8. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: The first substrate layer (1) and the second substrate layer (2) have the same size.

9. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: The copper plating layer (4) is adapted to the sizes of the first substrate layer (1) and the second substrate layer (2).

10. A printed circuit board fully embedded with copper blocks according to claim 1, characterized in that: Circuit layers are provided on both the first substrate layer (1) and the second substrate layer (2).

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