Printed circuit board

Abstract

The utility model discloses a printed circuit board, comprising a substrate which is provided with a through first through hole; the two core plates are arranged on the two sides of the base plate, second through holes are formed in the two core plates in a penetrating mode, the two second through holes are communicated with the first through hole, the inner diameter of the second through holes is larger than that of the first through hole, and first filling and leveling pieces are arranged in the first through hole and the second through holes. The first through hole and the second through hole are arranged to be stepped holes, so that stronger binding capacity can be provided for the first filling and leveling piece, and the problem that the bottom is layered after backflow is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of printed circuit boards, in particular to a printed circuit board. Background Art

[0002] Printed circuit boards (PCBs) are widely used in various fields, and almost all electronic devices contain corresponding printed circuit boards. The various layers of PCBs need to be connected through through holes, blind holes, and buried holes, but some blind holes and through holes need to be filled.

[0003] In the related art, flexible circuit boards are usually designed using a laser blind hole filling process, but for multi-stage HDI flexible board processes, there will be a problem of bottom delamination after reflow. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a printed circuit board, which can provide a first filling member with a stronger binding ability by setting the first through hole and the second through hole as step holes, thereby reducing the problem of bottom delamination after reflow.

[0005] According to the utility model, the printed circuit board includes: a substrate, on which a first through hole is provided; two core boards, the two core boards are arranged on both sides of the substrate, and the two core boards are each provided with a second through hole, the two second through holes are connected to the first through hole and the inner diameter of the second through hole is larger than the inner diameter of the first through hole, and a first filling member is provided in the first through hole and the second through hole.

[0006] According to the printed circuit board of the utility model, by setting the first through hole and the second through hole as step holes, a stronger binding ability can be provided to the first filling member, thereby reducing the problem of bottom delamination after reflow.

[0007] According to some embodiments of the present invention, the inner diameter of the first through hole is h1, the inner diameter of the second through hole is h2, and h1 and h2 satisfy the relationship: 40um

[0008] According to some embodiments of the present invention, the substrate includes: a first insulating layer and two first metal layers, the two first metal layers are arranged on both sides of the first insulating layer, and the first through hole penetrates the first insulating layer and the two first metal layers.

[0009] ​According to some embodiments of the utility model, the printed circuit board also includes: two adhesives, the adhesives are clamped between the core board and the substrate, at least one of the first metal layers is provided with a first blind hole spaced apart from the first through hole, and at least a portion of the adhesive is disposed in the first blind hole.

[0010] According to some embodiments of the present invention, the core board further includes: a second insulating layer and a second metal layer, the second metal layer is arranged on a side of the second insulating layer away from the substrate, and the second through hole penetrates the second insulating layer and the second metal layer.

[0011] According to some embodiments of the utility model, a third through hole is arranged on at least one of the core boards, the third through hole and the second through hole are arranged at intervals, the third through hole passes through the second insulating layer, the second metal layer and the adhesive and corresponds to the substrate, and a second filling member is arranged in the third through hole.

[0012] According to some embodiments of the utility model, a fourth through hole is provided on the first insulating layer and one of the first metal layers, a penetrating fifth through hole is provided on the core board corresponding to one of the first metal layers, the fifth through hole is connected to the fourth through hole and the inner diameter of the fifth through hole is larger than the inner diameter of the fourth through hole, and a third filling member is provided in the four through holes and the fifth through hole.

[0013] According to some embodiments of the present invention, the first filling piece is one of a flash plated metal layer and an electroplated metal layer; and / or, the second filling piece is one of a flash plated metal layer and an electroplated metal layer; and / or, the third filling piece is one of a flash plated metal layer and an electroplated metal layer.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 This is step 1 of manufacturing a printed circuit board according to an embodiment of the utility model;

[0017] Figure 2 This is step 2 of manufacturing the printed circuit board according to the embodiment of the utility model;

[0018] Figure 3 This is step three of manufacturing a printed circuit board according to an embodiment of the utility model;

[0019] Figure 4 This is step 4 of manufacturing a printed circuit board according to an embodiment of the utility model;

[0020] Figure 5 This is step five of manufacturing a printed circuit board according to an embodiment of the utility model;

[0021] Figure 6 This is step six of manufacturing the printed circuit board according to the embodiment of the utility model.

[0022] Reference numerals:

[0023] 10. substrate; 11. first through hole; 12. first insulating layer; 13. first metal layer; 14. first blind hole; 15. fourth through hole;

[0024] 20. core board; 21. second through hole; 22. second insulating layer; 23. second metal layer; 24. third through hole; 25. fifth through hole;

[0025] 30. Adhesive parts;

[0026] 40. First leveling piece; 41. Second leveling piece; 42. Third leveling piece. DETAILED DESCRIPTION

[0027] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0028] Reference below Figure 1-Figure 6 A printed circuit board according to an embodiment of the present utility model is described.

[0029] Reference Figure 1-6 As shown, the printed circuit board of the embodiment of the utility model includes: a substrate 10 and two core boards 20, the substrate 10 is provided with a first through hole 11, the two core boards 20 are arranged on both sides of the substrate 10, and the two core boards 20 are both provided with a second through hole 21, the two second through holes 21 are connected to the first through hole 11 and the inner diameter of the second through hole 21 is larger than the inner diameter of the first through hole 11, and a first filling member 40 is arranged in the first through hole 11 and the second through hole 21.

[0030] The substrate 10 is the supporting structure of the printed circuit board. The wires and lines on the substrate 10 provide electrical connections between electronic components. Through these wires and lines, the electronic components can communicate with each other and transmit electrical signals to form a complete circuit. In addition, the substrate 10 is usually composed of insulating materials, which can prevent electrical short circuits between wires and lines and protect the circuit from the external environment. Among them, the substrate 10 is FCCL (flexible copper cover composite material), and can also be replaced by FRCC (flame retardant copper cover composite material), and the thickness of the board can be selected according to the situation.

[0031] The core board 20 refers to the inner layer board in the PCB. Multiple core boards 20 can be stacked. Each core board 20 contains a part of the circuit design. They are connected through internal connections between layers, usually through holes, to form a complete circuit. Among them, the core board 20 can be FRCC (flame retardant copper coating composite material), and its board thickness can be selected according to the situation.

[0032] In the present embodiment, a core board 20 is respectively provided on both sides of the substrate 10, and a second through hole 21 is provided on both core boards 20. A first through hole 11 is provided on the substrate 10. The first through hole 11 and the second through hole 21 are interconnected and are coaxial holes. Since the inner diameter of the second through hole 21 is larger than the inner diameter of the first through hole 11, a step is formed in the first through hole 11 and the second through hole 21. The first filling member 40 in the first through hole 11 and the second through hole 21 is filled in the step hole. The step hole can provide the first filling member 40 with a stronger binding ability, thereby reducing the problem of bottom stratification after reflow.

[0033] The first through hole 11 and the second through hole 21 may be manufactured by laser processing.

[0034] Therefore, by setting the first through hole 11 and the second through hole 21 as stepped holes, a stronger binding ability can be provided to the first filling member 40, thereby reducing the problem of bottom delamination after reflow.

[0035] Reference Figure 1-6 As shown, the inner diameter of the first through hole 11 is h1, and the inner diameter of the second through hole 21 is h2, and h1 and h2 satisfy the relationship: 40um

[0036] Reference Figure 1-6 ​As shown, the substrate 10 includes: a first insulating layer 12 and two first metal layers 13, the two first metal layers 13 are arranged on both sides of the first insulating layer 12, and the first through hole 11 penetrates the first insulating layer 12 and the two first metal layers 13. Specifically. The substrate 10 is composed of the first insulating layer 12 and the two first metal layers 13. The first insulating layer 12 is also the base material, which can usually be composed of an insulating material, such as glass fiber reinforced epoxy resin (FR-4), polyimide (PI) or polyamide (PA), etc., and has good insulation performance and mechanical strength. The two first metal layers 13 can be copper layers, copper has good electrical conductivity, and circuit lines, pins, logos, etc. can be set. The first through hole 11 penetrates the first insulating layer 12 and the two first metal layers 13, and can transmit electrical signals between each layer.

[0037] Reference Figure 1-6 As shown, the printed circuit board also includes: two adhesives 30, the adhesives 30 are sandwiched between the core board 20 and the substrate 10, at least one first metal layer 13 is provided with a first blind hole 14 spaced apart from the first through hole 11, and at least part of the adhesive 30 is arranged in the first blind hole 14. The adhesive 30 is used to bond the core board 20 and the substrate 10 together, providing mechanical support for the entire PCB structure, which can enhance the strength and stability of the PCB, prevent deformation or warping between board layers, and, in the process of stacking multi-layer boards, there may be gaps between the core boards 20 and the core boards 20, such as the first blind hole 14, and the adhesive 30 can fill these gaps to ensure the tightness and uniformity of the PCB structure, ensure that the lines between different core boards 20 are well connected, and avoid circuit failures due to poor connections.

[0038] Reference Figure 1-6 As shown, the core board 20 also includes: a second insulating layer 22 and a second metal layer 23, the second metal layer 23 is arranged on the side of the second insulating layer 22 away from the substrate 10, and the second through hole 21 penetrates the second insulating layer 22 and the second metal layer 23. Specifically. The core board 20 is composed of a second insulating layer 22 and a second metal layer 23. The second insulating layer 22 is also a substrate, which can usually be composed of an insulating material, such as glass fiber reinforced epoxy resin (FR-4), polyimide (PI) or polyamide (PA), etc., which has good insulation performance and mechanical strength. The second metal layer 23 can be a copper layer, copper has good electrical conductivity, and circuit lines, pins, logos, etc. can be set. The second through hole 21 penetrates the second insulating layer 22 and the two second metal layers 23, and can transmit electrical signals between each layer.

[0039] Reference Figure 1-6As shown, at least one core board 20 is provided with a third through hole 24, the third through hole 24 and the second through hole 21 are arranged at intervals, the third through hole 24 penetrates the second insulating layer 22, the second metal layer 23 and the adhesive 30 and corresponds to the substrate 10, and a second filling member 41 is arranged in the third through hole 24. That is, in an optional embodiment of the utility model, a hole can be punched to the first metal layer 13 above the first insulating layer 12 by laser processing, and the first metal layer 13 is a copper layer, which can improve the binding force of the second filling member 41 and prevent the problem of bottom delamination after reflow.

[0040] Reference Figure 1-6 As shown, the first insulating layer 12 and one of the first metal layers 13 are provided with a fourth through hole 15, and the core board 20 corresponding to one of the first metal layers 13 is provided with a penetrating fifth through hole 25, the fifth through hole 25 is connected to the fourth through hole 15, and the inner diameter of the fifth through hole 25 is larger than the inner diameter of the fourth through hole 15, and the third filling member 42 is provided in the fourth through hole 15 and the fifth through hole 25. That is, in another optional embodiment of the utility model, laser processing can also be used to punch a hole in the first metal layer 13 below the first insulating layer 12 and form a step hole, and the first metal layer 13 is a copper layer, which can improve the binding force on the third filling member 42 and prevent the problem of bottom delamination after reflow.

[0041] And, in another optional embodiment of the utility model, a hole can be drilled from the back side of the PCB to the first metal layer 13 below the first insulating layer 12 by laser processing, and then filled. The first metal layer 13 is a copper layer, which can increase the binding force of the filling part and prevent the problem of bottom delamination after reflow.

[0042] In summary of the above embodiments, no matter whether a step hole or a blind hole is formed, the bottom and surrounding of the filling piece have a copper layer, and the binding force of the copper layer on the filling piece can avoid the problem of bottom delamination.

[0043] Reference Figure 1-6 As shown, the first filling member 40 is one of a flash-plated metal layer and an electroplated metal layer; and / or, the second filling member 41 is one of a flash-plated metal layer and an electroplated metal layer; and / or, the third filling member 42 is one of a flash-plated metal layer and an electroplated metal layer. In other words, the first filling member 40, the second filling member 41 and the third filling member 42 can all be flash-plated metal layers or electroplated metal layers formed by flash plating or electroplating.

[0044] It should also be noted that, referring to Figure 1-6As shown, the manufacturing process of the printed circuit board of the utility model is: first cut the material, then etch the two first metal layers 13 according to the size of the inner diameter of the first through hole 11, press the two core boards 20 with the two first adhesives 30 and the substrate 10, and then etch the two second metal layers 23 according to the inner diameter of the second through hole 21, perform laser processing from both sides of the PCB board to form a connected first through hole 11 and a second through hole 21, that is, a step hole, and finally fill the step hole by flash plating or electroplating.

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0047] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A printed circuit board, characterized in that: include: A substrate, wherein a first through hole is provided on the substrate; Two core plates, the two core plates are arranged on both sides of the substrate, the two core plates are each provided with a second through hole, the two second through holes are connected to the first through hole and the inner diameter of the second through hole is larger than the inner diameter of the first through hole, and a first filling member is provided in the first through hole and the second through hole.

2. The printed circuit board according to claim 1, characterized in that: The inner diameter of the first through hole is h1, the inner diameter of the second through hole is h2, and h1 and h2 satisfy the relationship: 40um<h1≤152um, 40um≤h2≤200um, h1<h2.

3. The printed circuit board according to claim 1, characterized in that: The substrate includes: a first insulating layer and two first metal layers, the two first metal layers are arranged on both sides of the first insulating layer, and the first through hole penetrates the first insulating layer and the two first metal layers.

4. The printed circuit board according to claim 3, characterized in that: Also includes: Two adhesive members are sandwiched between the core board and the substrate. At least one of the first metal layers is provided with a first blind hole spaced apart from the first through hole. At least part of the adhesive member is disposed in the first blind hole.

5. The printed circuit board according to claim 4, characterized in that: The core board further includes: a second insulating layer and a second metal layer, wherein the second metal layer is arranged on a side of the second insulating layer away from the substrate, and the second through hole penetrates the second insulating layer and the second metal layer.

6. The printed circuit board according to claim 5, characterized in that: A third through hole is arranged on at least one of the core plates, the third through hole and the second through hole are arranged at intervals, the third through hole passes through the second insulating layer, the second metal layer and the adhesive and corresponds to the substrate, and a second filling member is arranged in the third through hole.

7. The printed circuit board according to claim 5, characterized in that: A fourth through hole is provided on the first insulating layer and one of the first metal layers, and a penetrating fifth through hole is provided on the core board corresponding to one of the first metal layers. The fifth through hole is connected to the fourth through hole and the inner diameter of the fifth through hole is larger than the inner diameter of the fourth through hole. A third filling member is provided in the fourth through hole and the fifth through hole.

8. The printed circuit board according to any one of claims 1, 6 and 7, characterized in that: The first filling member is one of a flash-plated metal layer and an electroplated metal layer; and / or, The second filling member is one of a flash plated metal layer and an electroplated metal layer; and / or, The third filling member is one of a flash-plated metal layer and an electroplated metal layer.

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