Method for manufacturing a printed circuit board and printed circuit board

Abstract

The application discloses a printed circuit board manufacturing method and a printed circuit board. The manufacturing method comprises the following steps: performing circuit etching on a plurality of core boards, wherein a soft board is arranged between two core boards; and stacking and pressing the plurality of core boards and the soft board to form a circuit board body. The soft board comprises a flying tail part and a laminated part which are connected with each other. A blind hole is formed on the circuit board body, and the bottom of the blind hole is the connecting position of the flying tail part and the laminated part. The soft board is pulled out from the blind hole. The blind hole is formed on the circuit board body, the soft board is pulled out from the blind hole, and the utilization rate of the printed circuit board is ensured while the flying tail structure is formed.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board technology, and in particular to a method for manufacturing a printed circuit board and a printed circuit board. Background Technology

[0002] A rigid-flex PCB is a single unit formed by laminating a rigid PCB and a flexible PCB. To meet various design requirements, the flexible PCB extends out from the rigid PCB.

[0003] In related technologies, flexible boards extend from the outer edge of the rigid board. If they are to extend from the middle of the rigid board, steps must be designed to extend from the milled part. These extended flexible boards are also called flying tail structures, which means that a section of flexible board flies out from the rigid board.

[0004] However, designing steps requires milling out the entire rigid board above the flexible board, resulting in no circuitry in that area, making it impossible to assemble components, wasting space, and reducing the utilization rate of the rigid board. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method that, by forming blind holes in the main body of the circuit board, allows the flexible board to be extracted from the blind holes, thereby ensuring the utilization rate of the printed circuit board while forming a flytail structure.

[0006] The present invention further proposes a printed circuit board.

[0007] According to a first aspect of the present invention, a method for manufacturing a printed circuit board includes: performing circuit etching on a multilayer core board, wherein a flexible board is disposed between two core boards; stacking and laminating the multilayer core boards and the flexible board to form a circuit board body; the flexible board includes an exit portion and a laminating portion connected to each other, and a blind hole is formed on the circuit board body, the bottom of the blind hole being the connection point between the exit portion and the laminating portion; and extracting the exit portion from the blind hole.

[0008] According to the method for manufacturing a printed circuit board according to an embodiment of the present invention, by forming blind holes on the main body of the circuit board, the flexible board is extracted from the blind holes, which can form a flying tail structure while ensuring the utilization rate of the printed circuit board.

[0009] According to some embodiments of the present invention, the method for forming blind holes on the circuit board body further includes: milling the circuit board body to form blind holes on the circuit board body; or, first milling the multilayer core board on one side of the thickness direction at the connection between the flyout portion and the laminate portion, and then stacking and pressing the multilayer core board and the flexible board together.

[0010] According to some embodiments of the present invention, the width of the blind hole is greater than the width of the flexible board.

[0011] According to some embodiments of the present invention, after forming a blind hole on the circuit board body, the method further includes: removing at least one of the core plates on one side of the flyout portion in the thickness direction to form a cavity on one side of the flyout portion in the thickness direction.

[0012] According to some embodiments of the present invention, after stacking and laminating multiple layers of the core board and the flexible board to form the circuit board body, the process further includes: drilling holes in the circuit board body, electroplating, and performing pattern processing on the core boards on both sides of the thickness direction of the circuit board body.

[0013] According to some embodiments of the present invention, before the ejector portion is pulled out from the blind hole, the process further includes: machining the shape of the circuit board body.

[0014] According to a second aspect of the present invention, the printed circuit board is manufactured by the method described above.

[0015] According to some embodiments of the present invention, there are two blind holes, which are respectively disposed on both sides of the circuit board body in the thickness direction, and there are two flexible boards, which are respectively extracted from the two blind holes.

[0016] According to some embodiments of the present invention, there are at least two flexible boards, and the at least two flexible boards are respectively disposed on different sides of the circuit board body in the length direction and the width direction.

[0017] According to some embodiments of the present invention, a flexible board is disposed between two of the core boards, and a portion of the plurality of core boards is provided with a prepreg between two adjacent core boards.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a top view of a printed circuit board according to an embodiment of the present invention; Figure 2 This is a side view of a printed circuit board according to an embodiment of the present invention. Figure 1 ; Figure 3 This is a side view of a printed circuit board according to an embodiment of the present invention. Figure 2 ; Figure 4 This is a side view of another embodiment of a printed circuit board according to an embodiment of the present invention; Figure 5 This is a top view of yet another embodiment of a printed circuit board according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a printed circuit board in an unpressed state according to an embodiment of the present invention.

[0020] Figure label: 100. Printed circuit boards; 11. Core board; 12. Flexible board; 121. Extrusion section; 122. Laminated section; 13. Blind hole; 14. Cavity; 15. Prepreg. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0022] The following is for reference. Figures 1-6 A method for manufacturing a printed circuit board 100 according to an embodiment of the present invention is described, and the present invention also provides a printed circuit board 100.

[0023] The method for manufacturing a printed circuit board 100 according to an embodiment of the present invention includes: performing circuit etching on a multilayer core board 11; removing some copper foil on the core board 11 through steps such as dry film processing, exposure, and development; transferring the circuit lines to be retained to form a clear circuit on the core board 11; subjecting the core board 11 with the inner layer circuit etching completed to high temperature and high pressure bonding to form a multilayer core board 11; and after cooling and curing, forming a rigid circuit board, also called a hard board.

[0024] A flexible circuit board 12 is disposed between the two core boards 11. The flexible circuit board 12, also called a flexible printed circuit board, refers to a printed circuit made of a flexible insulating substrate, which has the characteristics of bending, winding, and folding. The multilayer core boards 11 and flexible circuit boards 12 are stacked and pressed together to form the main body of the circuit board.

[0025] The flexible board 12 includes a flyout portion 121 and a laminating portion 122 connected to each other. The flyout portion 121 is a flytail structure extending from the multilayer core board 11. The laminating portion 122 is pressed together with the multilayer core board 11 to maintain the electrical connection between the flexible board 12 and the multilayer core board 11.

[0026] Reference Figures 1-3As shown, a blind hole 13 is formed on the main body of the circuit board. The bottom of the blind hole 13 is the connection point between the flyout part 121 and the laminating part 122. The flyout part 121 is pulled out from the blind hole 13. In other words, taking the flyout structure set on the front side of the printed circuit board 100 as an example, the blind hole 13 is only formed on the multilayer core board 11 above the flexible board 12. The flexible board 12 can be pulled out from the blind hole 13 without removing all the core boards 11 above the flexible board 12. The core boards 11 above the flexible board 12 can still be used to assemble electrical appliances. The utilization rate of the printed circuit board 100 is high, which greatly improves the wiring utilization rate of the rigid board and increases the effective area for device assembly.

[0027] Therefore, by forming blind holes 13 on the main body of the circuit board, the flexible board 12 is pulled out from the blind holes 13, which can form a flying tail structure while ensuring the utilization rate of the printed circuit board 100.

[0028] The method for forming blind holes 13 on the circuit board body also includes: milling the circuit board body to form blind holes 13 on the circuit board body. Specifically, the depth of the outermost core board 11 from the flexible board 12 is calculated in advance, and a portion of the core board 11 is milled off using a controlled depth milling method, which exposes the flexible board 12 at the bottom of the blind hole 13.

[0029] Alternatively, the multilayer core board 11 on the thickness side of the connection between the flyout portion 121 and the laminating portion 122 can be milled first, and then the multilayer core board 11 and the flexible board 12 can be stacked and laminated. That is, before the flexible board 12 and the multilayer core board 11 are laminated, on the side of the printed circuit board 100 where the flyout tail structure needs to be made, part of the core board 11 can be milled off using a controlled depth milling method, and then laminated. This can avoid damaging the structure of the flexible board 12 and improve the yield of the printed circuit board 100.

[0030] The width of the blind hole 13 is greater than the width of the flexible board 12, so that the flexible board 12 can be smoothly pulled out from the blind hole 13.

[0031] Reference Figures 2-3 As shown, after forming the blind hole 13 on the circuit board body, the process further includes removing at least one core board 11 on one side of the ejector portion 121 in the thickness direction to form a cavity 14 on one side of the ejector portion 121 in the thickness direction. Specifically, since the layers are tightly connected during the lamination of the circuit board body, in order to extract the flexible board 12 from the blind hole 13, it is necessary to remove at least one core board 11 on one side of the flexible board 12. The cavity 14 formed in this way allows the flexible board 12 to have room to move, ensuring that the flexible board 12 will not be stuck. At the same time, during the extraction process, it will not come into tight frictional contact with the core board 11, thereby protecting the flexible board 12 from damage.

[0032] Furthermore, after stacking and laminating the multilayer core board 11 and flexible board 12 to form the circuit board body, the process also includes: drilling holes in the circuit board body, electroplating, and pattern processing of the core boards 11 on both sides of the circuit board body in the thickness direction. Specifically, after laminating to form the circuit board body, drilling, copper plating, and copper electroplating are performed to establish interlayer conductive channels and realize electrical connections between layers. Then, the outer layer of the circuit board body undergoes another pattern transfer and etching to form surface circuitry. Further processes such as surface solder mask application, silkscreen printing, and surface treatment using chemical nickel gold or HASL processing can also be performed.

[0033] Furthermore, before removing the flexible board 12 from the blind hole 13, the process also includes: processing the shape of the circuit board body, cutting the circuit board body into the required size and shape to ensure precise alignment with the product's casing, slots, connectors, and other structures, and reserving mounting structures such as holes and slots, chamfers, etc.

[0034] According to a second aspect embodiment of the present invention, the printed circuit board is manufactured by a method for manufacturing printed circuit boards. The printed circuit board 100 manufactured by this method can not only create a flying tail structure, but also improve the wiring utilization of the core board 11 and increase the effective area for device assembly.

[0035] Reference Figure 4 As shown, in some embodiments, there can be two blind holes 13, each located on one side of the circuit board body in the thickness direction. There can also be two flexible boards 12, each extracted from one of the two blind holes 13. Alternatively, a "flying tail" structure can be provided on both the front and back of the circuit board body. Two blind holes 13 are formed on both sides of the circuit board body in the thickness direction using a milling cutter, and two flexible boards 12 are pressed together inside. The two flexible boards 12 are then extracted from the two blind holes 13 to form the flying tail structure. This provides a very promising application scenario for future multifunctional, highly integrated, and miniaturized rigid-flex products, which is beneficial for enhancing product competitiveness.

[0036] Reference Figure 5 As shown, there can be at least two flexible printed circuit boards 12, which are respectively disposed on different sides of the circuit board body in the length and width directions. That is, the flexible printed circuit boards 12 can extend from the circuit board body in the length and width directions and can be disposed in different positions to meet various design requirements of the printed circuit board 100.

[0037] A flexible board 12 is disposed between two core boards 11, and a prepreg 15 is disposed between two adjacent core boards 11 in some of the multiple core boards 11, as shown in the figure. Figure 6As shown, the prepreg 15 on the left is used to bond two adjacent core boards 11 on the right to improve the stability of the printed circuit board 100. When forming blind holes 13 with a milling cutter and removing at least one core board 11 on one side of the flexible board 12, the prepreg 15 needs to be processed to prevent the prepreg 15 from affecting the extraction of the flexible board 12.

[0038] In summary, the processing steps of the printed circuit board 100 are as follows: Circuit etching is performed on the multilayer core board 11. Through steps such as dry film processing, exposure, and development, some copper foil on the core board 11 is removed, and the desired circuit lines are transferred to it, forming a clear circuit on the core board 11. The core board 11 with the inner layer circuit etching completed is then subjected to high-temperature and high-pressure lamination to form the multilayer core board 11. After cooling and curing, a rigid board is formed. The core board 11 and prepreg 15 on the side where the tail structure is to be made are processed. At least one core board 11 and the prepreg 15 bonded to it are removed to leave space for the flexible board 12. The multilayer core board 11 and the flexible board 12 are then laminated, followed by drilling, electroplating, pattern circuit etching, surface solder mask application, silkscreen printing, and surface treatment processes such as chemical nickel gold or HASL. Calculate the depth of the outermost core board 11 from the flexible board 12 in advance, and use a milling cutter to mill part of the core board 11 using controlled depth milling. At this time, the flexible board 12 at the bottom of the blind hole 13 is exposed. Perform the final shape processing to complete the printed circuit board manufacturing. At this time, the flexible board 12 can be extracted from the cavity 14 and the blind hole 13.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0041] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for manufacturing a printed circuit board, characterized in that, The manufacturing method includes: Circuit etching is performed on a multilayer core board, wherein a flexible board is disposed between two of the core boards; The core board and the flexible board are stacked and pressed together to form the circuit board body; The flexible circuit board includes an interconnected flyout portion and a laminate portion, and a blind hole is formed on the circuit board body. The bottom of the blind hole is the connection point between the flyout portion and the laminate portion. The ejected part is pulled out from the blind hole.

2. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The method for forming blind vias on the circuit board body further includes: The circuit board body is milled to form blind holes on the circuit board body; Alternatively, the multi-layer core board on the thickness side of the connection between the flying part and the laminated part can be milled first, and then the multi-layer core board and the flexible board can be stacked and pressed together.

3. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The width of the blind hole is greater than the width of the flexible board.

4. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The process of forming blind vias on the circuit board body further includes: At least one of the core plates on the thickness side of the ejected portion is removed to form a cavity on the thickness side of the ejected portion.

5. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The process of stacking and laminating multiple layers of the core board and the flexible board to form the circuit board body further includes: The circuit board body is drilled and electroplated, and the core boards on both sides of the circuit board body in the thickness direction are patterned.

6. The method for manufacturing a printed circuit board according to claim 1, characterized in that, Before the ejector portion is pulled out from the blind hole, the method further includes: The shape of the circuit board body is processed.

7. A printed circuit board, characterized in that, The printed circuit board is manufactured by the method of manufacturing a printed circuit board according to any one of claims 1-6.

8. The printed circuit board according to claim 7, characterized in that, There are two blind holes, which are respectively located on both sides of the circuit board body in the thickness direction. There are two flexible boards, which are respectively pulled out from the two blind holes.

9. The printed circuit board according to claim 7, characterized in that, The flexible circuit board is at least two, and the at least two flexible circuit boards are respectively disposed on different sides of the circuit board body in the length direction and the width direction.

10. The printed circuit board according to claim 7, characterized in that, The flexible board is disposed between two of the core boards, and a portion of the multiple core boards has a prepreg disposed between two adjacent core boards.

Images