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 printed circuit board manufacturing method comprises the following steps: removing a first part of a second copper layer; removing a part of an outer core board corresponding to the first part; and at least partially cutting and removing a part of a first substrate part of a flexible substrate corresponding to a first copper layer opening, the first substrate part corresponding to the first part and a second substrate part corresponding to a second part. Thus, after removing the part of the outer core board corresponding to the first part, the part of the first substrate part of the flexible substrate corresponding to the first copper layer opening is at least partially cut and removed. In this way, the part of the soft core board corresponding to the first part can be cut into one or more strip structures distributed at intervals, and through the flexible connection between the strip structure and the second substrate part, not only can the strip structure absorb the micro-deformation caused by stress through displacement, but also the independent displacement of the corresponding parts of the first substrate part and the second substrate part can be realized.

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] With the continuous development of semiconductor technology, the packaging process of circuit boards is also constantly improving, and the requirements for the flexibility of circuit boards are becoming increasingly higher.

[0003] In related technologies, rigid boards do not have the ability to bend or deform, and once fixed, they cannot cope with any displacement and are prone to breakage; although rigid-flex boards have the ability to bend or deform, the flexible area moves uniformly and deforms as a whole, which cannot achieve independent displacement or local deformation of different positions on the printed circuit board. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a method for manufacturing a printed circuit board that is more reliable, not only solving the problem of micro-deformation caused by force through displacement, but also enabling independent displacement of different positions on the printed circuit board.

[0005] The present invention further proposes a printed circuit board.

[0006] A method for manufacturing a printed circuit board according to the present invention includes: preparing a flexible core board, wherein the flexible core board includes a flexible substrate and a first copper layer, the flexible substrate having an upper surface and a lower surface disposed opposite to each other in a first direction, and the first copper layer being disposed on the upper surface and the lower surface of the flexible substrate respectively; forming a first blind hole in the flexible core board, and electroplating a first conductive copper layer in the first blind hole, wherein the first conductive copper layer in the first blind hole is electrically connected to the first copper layer on the upper and lower surfaces of the flexible substrate respectively; and electroplating a first conductive copper layer on the upper and lower surfaces of the flexible core board. Holes are made in the copper layer to fabricate inner layer circuitry; an upper outer layer core board and a lower outer layer core board are respectively added to the upper and lower surfaces of the flexible circuit board core board. Both the upper outer layer core board and the lower outer layer core board include a dielectric layer and a second copper layer. One side of the dielectric layer in a first direction is in contact with the flexible circuit board core board, and the second copper layer is disposed on the other side of the dielectric layer in the first direction. Second blind holes are made in the second copper layers of both the upper outer layer core board and the lower outer layer core board, and a second conductive copper layer is electroplated in the second blind holes, wherein the second conductive copper layer is electrically connected to the first conductive copper layer. The first portion of the second copper layer of the upper outer core board and the lower outer core board is removed, and a hole is made in the second portion to form an outer layer circuit. The second copper layer of the upper outer core board and the lower outer core board includes a first portion and a second portion arranged in a left-right direction. The portions of the upper outer core board and the lower outer core board corresponding to the first portion are removed. The portion of the first substrate portion of the flexible substrate corresponding to the hole in the first copper layer is at least partially cut away. The flexible substrate includes a first substrate portion and a second substrate portion arranged in a left-right direction. The first substrate portion corresponds to the first portion, and the second substrate portion corresponds to the second portion. The first conductive copper layer is located in the second substrate portion, and the second conductive copper layer is located in the second portion.

[0007] Therefore, after removing the portion of the outer core board corresponding to the first part, at least part of the portion of the first substrate portion of the flexible substrate corresponding to the opening of the first copper layer is cut away. This allows the flexible core board portion corresponding to the first part to be cut into one or more spaced strip structures. The strip structures are then flexibly connected to the second substrate portion, which not only allows the strip structures to absorb micro-deformation caused by force through displacement, but also enables independent displacement of the corresponding portions of the first substrate portion and the second substrate portion.

[0008] In some examples of the present invention, the step of at least partially cutting away the portion of the first substrate portion of the flexible substrate corresponding to the first copper layer opening, wherein the flexible substrate includes a first substrate portion and a second substrate portion, the first substrate portion corresponding to the first portion and the second substrate portion corresponding to the second portion, includes: cutting off the middle region in the front-back direction of the portion of the first substrate portion corresponding to the first copper layer opening, and retaining the two end regions in the front-back direction of the portion of the first substrate portion corresponding to the first copper layer opening.

[0009] In some examples of the present invention, the flexible substrate is a polyimide film.

[0010] In some examples of the present invention, the step of removing a first portion of the second copper layer of the upper outer core board and the lower outer core board and making a hole in the second portion to form an outer layer circuit, wherein the second copper layer of the upper outer core board and the lower outer core board includes a first portion and a second portion arranged in a left-right direction, further includes: applying a first solder resist ink at the opening of the second copper layer in the second portion.

[0011] In some examples of the present invention, the step of setting solder resist ink at the opening of the second copper layer in the second part further includes: simultaneously setting a second solder resist ink on the second conductive copper layer and the second copper layer connected to the second conductive copper layer, wherein the thickness of the first solder resist ink in the vertical direction is greater than the thickness of the second copper layer in the vertical direction, and the second solder resist ink is flush with the first solder resist ink.

[0012] In some examples of the present invention, the step of removing the portions of the upper outer core plate and the lower outer core plate corresponding to the first portion includes: providing a cover film on the second copper layer of the second portion of the upper outer core plate and the lower outer core plate, the cover film being flush with the first solder resist ink and / or the second solder resist ink.

[0013] In some examples of the present invention, the first blind via extends from the first copper layer on the upper surface through the flexible substrate and reaches the first copper layer on the lower surface; and / or the second blind via extends from the second copper layer through the dielectric layer and reaches the first copper layer.

[0014] In some examples of the present invention, the medium layer is pure glue or flowable PP.

[0015] In some examples of the present invention, before the step of adding an upper outer core plate and a lower outer core plate to the upper and lower surfaces of the flexible board core plate respectively, the method further includes: attaching micro-adhesive films to the upper and lower surfaces of the flexible board core plate respectively, wherein the micro-adhesive films correspond to the portions of the first copper layer openings on the first substrate portion.

[0016] The printed circuit board according to the embodiments of the present invention is applicable to the above-described method for manufacturing printed circuit boards.

[0017] 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

[0018] 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 flowchart of a method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 2 This is a flowchart of a method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a flexible board core board according to an embodiment of the present invention; Figure 4 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 5 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 6 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 7 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 8 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 9 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 10 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 11 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 12 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 13 This is a cross-sectional view during the fabrication process of a printed circuit board according to an embodiment of the present invention; Figure 14 This is a cross-sectional view of a printed circuit board after it has been manufactured according to an embodiment of the present invention.

[0019] Figure label: 100. Printed circuit boards; 10. Flexible core board; 101. Flexible substrate; 1011. First substrate portion; 1012. Second substrate portion; 102. First copper layer; 201, First blind hole; 202, Second blind hole; 301, First conductive copper layer; 302, Second conductive copper layer; 401. Inner layer circuitry; 402. Outer layer circuitry; 501, Upper outer core board; 502, Lower outer core board; 503, Dielectric layer; 504, Second copper layer; 5041, First part; 5042, Second part; 601. First solder resist ink; 602. Second solder resist ink; 70. Covering film. Detailed Implementation

[0020] 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.

[0021] The following is for reference. Figures 1-14A method for manufacturing a printed circuit board 100 according to an embodiment of the present invention is described, which can produce the printed circuit board 100.

[0022] Combination Figures 1-14 As shown, the manufacturing method of the printed circuit board 100 according to the present invention mainly includes the following steps: preparing a flexible core board 10, wherein the flexible core board 10 includes a flexible substrate 101 and a first copper layer 102, the flexible substrate 101 has an upper surface and a lower surface disposed opposite to each other in a first direction, and the first copper layer 102 is respectively disposed on the upper surface and the lower surface of the flexible substrate 101; forming a first blind hole 201 on the flexible core board 10, and electroplating a first conductive copper layer 301 in the first blind hole 201, wherein the first conductive copper layer 301 in the first blind hole 201 is respectively connected to the flexible substrate. The first copper layer 102 on the upper and lower surfaces of the flexible circuit board 10 is electrically connected; holes are made in the first copper layer 102 on the upper and lower surfaces of the flexible circuit board 10 to fabricate inner layer circuitry 401; an upper outer layer core board 501 and a lower outer layer core board 502 are respectively added to the upper and lower surfaces of the flexible circuit board 10. Both the upper outer layer core board 501 and the lower outer layer core board 502 include a dielectric layer 503 and a second copper layer 504. One side of the dielectric layer 503 in the first direction is in contact with the flexible circuit board 10, and the second copper layer 504 is disposed on the other side of the dielectric layer 503 in the first direction; the second copper layer 504 of the upper outer layer core board 501 and the lower outer layer core board 502 are connected in the second copper layer 504. Each layer 504 has a second blind via 202, and a second conductive copper layer 302 is electroplated in the second blind via 202, wherein the second conductive copper layer 302 is electrically connected to the first conductive copper layer 301; the first portion 5041 of the second copper layer 504 of the upper outer core plate 501 and the lower outer core plate 502 is removed, and a hole is made in the second portion 5042 to fabricate the outer layer circuit 402, wherein the second copper layer 504 of the upper outer core plate 501 and the lower outer core plate 502 includes a first portion 5041 and a second portion 5042 arranged in a left-right direction; the upper outer core plate 501 and the lower outer core plate 502 are then removed from the second copper layer 504. The outer core board 502 is partially removed from the portion corresponding to the first portion 5041; at least part of the portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102 is cut and removed. The flexible substrate 101 includes a first substrate portion 1011 and a second substrate portion 1012 arranged in a left-right direction. The first substrate portion 1011 corresponds to the first portion 5041, and the second substrate portion 1012 corresponds to the second portion 5042. The first conductive copper layer 301 is located in the second substrate portion 1012, and the second conductive copper layer 302 is located in the second portion 5042.

[0023] Specifically, firstly, a flexible core board 10 is prepared, wherein the flexible substrate 101 in the flexible core board 10 has good flexibility and can provide a flexible foundation and support structure for the printed circuit board 100. A first copper layer 102 is provided on both the upper and lower surfaces of the flexible substrate 101, and circuits can be fabricated on the upper and lower surfaces of the flexible substrate 101 respectively. The flexible substrate 101 and the first copper layer 102 together constitute a flexible base structure that can be wired on both sides, which serves as the basis for the subsequent fabrication process of the printed circuit board 100.

[0024] Furthermore, a first blind hole 201 is formed on the flexible core board 10, wherein the depth of the first blind hole 201 is the total height of the flexible substrate 101 and the first copper layer 102 on its upper surface, so that after the first conductive copper layer 301 is electroplated in the first blind hole 201, the first copper layer 102 on the upper and lower surfaces of the flexible substrate 101 can be electrically connected, thereby realizing the conduction between the first copper layer 102 on the upper and lower surfaces of the flexible substrate 101.

[0025] Furthermore, in some embodiments of the present invention, a portion of the copper layer on the upper and lower surfaces of the flexible substrate 101 can be removed by exposure, development and etching steps, that is, opening is performed on the first copper layer 102 on the upper and lower surfaces of the flexible core board 10, thereby patterning the first copper layer 102 on the upper and lower surfaces of the flexible substrate 101 to form the required circuit lines and complete the fabrication of the inner layer circuit 401.

[0026] Furthermore, an upper outer core board 501 and a lower outer core board 502 are respectively added to the upper and lower surfaces of the flexible core board 10. Both the upper outer core board 501 and the lower outer core board 502 include a dielectric layer 503 and a second copper layer 504. The dielectric layer 503 is disposed between the first copper layer 102 and the second copper layer 504. The dielectric layer 503 has an insulating function and can electrically isolate the first copper layer 102 and the second copper layer 504.

[0027] Furthermore, a second blind hole 202 is formed in the second copper layer 504 of both the upper outer core plate 501 and the lower outer core plate 502. The depth of the second blind hole 202 is the distance from the upper surface of the second copper layer 504 to the upper surface of the first copper layer 102 or from the lower surface of the second copper layer 504 to the lower surface of the first copper layer 102. This allows the first copper layer 102 and the second copper layer 504 to be electrically connected after the second conductive copper layer 302 is electroplated in the second blind hole 202, thereby achieving conductivity between the first copper layer 102 and the second copper layer 504.

[0028] Furthermore, the second copper layer 504 of the upper outer core board 501 and the lower outer core board 502 includes a first portion 5041 and a second portion 5042 arranged in a left-right direction. All the copper layer of the first portion 5041 is removed, and a portion of the copper layer of the second portion 5042 is removed to create holes in the second portion 5042, thereby fabricating the outer layer circuitry 402 on the second portion 5042. Specifically, in some embodiments of the present invention, a portion of the copper layer of the second portion 5042 of the second copper layer 504 can be removed by steps such as exposure development and etching. That is, holes are created in the second copper layer 504 on the upper surface of the upper outer core board 501 and the lower surface of the lower outer core board 502, thereby patterning the second copper layer 504 on the upper surface of the upper outer core board 501 and the lower surface of the lower outer core board 502 to form the required circuit lines, completing the fabrication of the outer layer circuitry 402, and thus realizing multi-layer wiring on the printed circuit board 100, increasing the wiring density of the printed circuit board 100.

[0029] Furthermore, the dielectric layer 503 corresponding to the upper outer core board 501 and the lower outer core board 502 and the first part 5041 is removed to expose the flexible core board 10 corresponding to the area of ​​the first part 5041.

[0030] Furthermore, the flexible substrate 101 includes a first substrate portion 1011 and a second substrate portion 1012 arranged in a left-right direction. The first substrate portion 1011 corresponds to the first portion 5041, and the second substrate portion 1012 corresponds to the second portion 5042. At least part of the portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102 is cut away. That is, the area on the surface of the first substrate portion 1011 where the first copper layer 102 is not provided is cut away, leaving the first copper layer 102 and the first substrate portion 1011 corresponding to the pattern of the inner layer circuit 401 in the first direction. The first conductive copper layer 301 is located in the second substrate portion 1012, and the second conductive copper layer 302 is located in the second portion 5042.

[0031] Therefore, after removing the corresponding portions of the upper outer core board 501 and the lower outer core board 502 from the first portion 5041, at least partially cutting away the portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102, the volume of the printed circuit board 100 can be reduced, the space occupied by the printed circuit board 100 can be reduced, and the flexible core board 10 portion corresponding to the first portion 5041 can be cut into one or more spaced strip structures. This not only allows the strip structures to be flexibly connected to the second substrate portion 1012, allowing each strip structure to move under force, so as to absorb or compensate for the micro-deformation of the strip structure caused by force through displacement, but also enables independent displacement of the corresponding portions of the first substrate portion 1011 and the corresponding portions of the second substrate portion 1012, improving the local mobility and flexibility of the printed circuit board 100.

[0032] In some embodiments of the present invention, after the inner layer circuit 401 is formed, the cover film 70 may be partially or fully laminated as needed.

[0033] In some embodiments of the present invention, the shape of the blind hole includes, but is not limited to, at least one of trapezoidal, cylindrical, inverted conical, and regular conical.

[0034] Combination Figures 1-14 As shown, the step of cutting away at least a portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102 is as follows: the flexible substrate 101 includes a first substrate portion 1011 and a second substrate portion 1012, the first substrate portion 1011 corresponds to the first portion 5041 and the second substrate portion 1012 corresponds to the second portion 5042. The step includes cutting away the middle region in the front-back direction of the portion in the first substrate portion 1011 corresponding to the opening of the first copper layer 102, and retaining the two end regions in the front-back direction of the portion in the first substrate portion 1011 corresponding to the opening of the first copper layer 102.

[0035] Specifically, when at least partially cutting away the portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102, only the middle region in the front-back direction of the portion of the first substrate portion 1011 corresponding to the opening of the first copper layer 102 is removed, while the two end regions in the front-back direction of the portion of the first substrate portion 1011 corresponding to the opening of the first copper layer 102 are retained. This allows the formation of filament-like structures in the two end regions in the front-back direction of the first substrate portion 1011. Furthermore, a flexible connection can be established between the strip structure of the first substrate portion 1011 and the second substrate portion 1012 through the filament-like structure, thereby allowing each strip structure to displace when subjected to force, so as to absorb or compensate for the micro-deformation of the strip structure caused by force through displacement.

[0036] Combination Figures 3-14As shown, the flexible substrate 101 is a polyimide film. Specifically, the polyimide film has good insulation properties, making the flexible substrate 101 a polyimide film, which can electrically isolate the first copper layer 102 on the upper and lower surfaces of the flexible substrate 101, thereby improving the stability and reliability of the inner layer circuitry 401 on the printed circuit board 100; the polyimide film has good flexibility, making the flexible substrate 101 a polyimide film, which allows for certain deformation or bending under the premise of structural stability of the flexible substrate 101, which can help to solve the problem of micro-deformation caused by force by displacing the strip structure of the first substrate portion 1011; in addition, the polyimide film has a small thickness, making the flexible substrate 101 a polyimide film, thereby reducing the volume of the printed circuit board 100.

[0037] Combination Figure 1 , Figure 2 and Figure 11 As shown, the first portion 5041 of the second copper layer 504 of the upper outer core board 501 and the lower outer core board 502 is removed, and a hole is made in the second portion 5042 to fabricate the outer layer circuit 402. After the step of the second copper layer 504 of the upper outer core board 501 and the lower outer core board 502 including the first portion 5041 and the second portion 5042 arranged in the left and right direction, the method further includes: applying a first solder resist ink 601 at the opening of the second copper layer 504 of the second portion 5042.

[0038] Specifically, the first solder resist ink 601 has good insulation properties. The first solder resist ink 601 is applied at the opening of the second copper layer 504 of the second part 5042. That is, the first solder resist ink 601 is applied in the non-circuit area of ​​the second copper layer 504. This can prevent short circuits between adjacent lines, which can help reduce the spacing between adjacent lines and increase the wiring density of the printed circuit board 100.

[0039] Combination Figure 1 , Figure 2 and Figure 11 As shown, the step of setting solder resist ink at the opening of the second copper layer 504 in the second part 5042 further includes: simultaneously setting a second solder resist ink 602 on the second conductive copper layer 302 and the second copper layer 504 connected to the second conductive copper layer 302, wherein the thickness of the first solder resist ink 601 in the vertical direction is greater than the thickness of the second copper layer 504 in the vertical direction, and the second solder resist ink 602 is flush with the first solder resist ink 601.

[0040] Specifically, the second solder resist ink 602 also has good insulation properties. The second solder resist ink 602 is applied to the second conductive copper layer 302 and the second copper layer 504 connected to the second conductive copper layer 302. This can electrically isolate the second conductive copper layer 302 and the second copper layer 504 connected to the second conductive copper layer 302, preventing the second conductive copper layer 302 or the second copper layer 504 connected to the second conductive copper layer 302 from accidentally touching other lines and causing circuit failure. This can improve the stability and reliability of the printed circuit board 100.

[0041] Furthermore, since the thickness of the second conductive copper layer 302 and the second copper layer 504 connected to the second conductive copper layer 302 are the same as the thickness of the second copper layer 504 in the non-opening area of ​​the second part 5042, the first solder resist ink 601 is disposed at the opening of the second copper layer 504 in the second part 5042, and the second solder resist ink 602 is disposed on the second conductive copper layer 302 and the second copper layer 504 connected to the second conductive copper layer 302. Therefore, the thickness of the first solder resist ink 601 in the vertical direction is greater than the thickness of the second copper layer 504 in the vertical direction, and the thickness of the first solder resist ink 601 is equal to the total thickness of the second solder resist ink 602 and the second copper layer 504. This allows the second solder resist ink 602 and the first solder resist ink 601 to be flush with each other, which can improve the flatness and aesthetics of the printed circuit board 100.

[0042] In addition, electrical connection between the outer layer circuit 402 or external device and the inner layer circuit 401 can be achieved by electrically connecting the second copper layer 504 connected to the second conductive copper layer 302.

[0043] Combination Figure 1 , Figure 2 and Figure 13 As shown, the step of removing the corresponding portions of the upper outer core plate 501 and the lower outer core plate 502 from the first portion 5041 includes: providing a cover film 70 on the second copper layer 504 of the second portion 5042 of the upper outer core plate 501 and the lower outer core plate 502, wherein the cover film 70 is flush with the first solder resist ink 601 and / or the second solder resist ink 602.

[0044] Specifically, a cover film 70 is provided on the second copper layer 504 of the second part 5042 of the upper outer core board 501 and the lower outer core board 502. That is, a cover layer is provided on the outer surface of the outer circuit 402. This can cover the exposed copper layer on the outer surface of the printed circuit board 100, thereby not only preventing accidental contact between exposed copper layers that could lead to circuit failure and preventing leakage of the printed circuit board 100, but also improving the stability and reliability of the printed circuit board 100. Furthermore, it can prevent physical damage such as scratches, wear, or corrosion of the exposed copper layer, thus extending the service life of the printed circuit board 100.

[0045] Furthermore, the cover film 70 is flush with the first solder resist ink 601 and / or the second solder resist ink 602, which can improve the flatness and aesthetics of the printed circuit board 100.

[0046] Combination Figures 3-14 As shown, the first blind via 201 penetrates the flexible substrate 101 from the first copper layer 102 on the upper surface and reaches the first copper layer 102 on the lower surface; and / or the second blind via 202 penetrates the dielectric layer 503 from the second copper layer 504 and reaches the first copper layer 102.

[0047] Specifically, the first blind hole 201 penetrates the flexible substrate 101 from the first copper layer 102 on the upper surface and reaches the first copper layer 102 on the lower surface. That is, the depth of the first blind hole 201 is the total height of the flexible substrate 101 and the first copper layer 102 on its upper surface, so that after the first conductive copper layer 301 is electroplated in the first blind hole 201, the first copper layers 102 on the upper and lower surfaces of the flexible substrate 101 can be electrically connected, thereby realizing the conduction between the first copper layers 102 on the upper and lower surfaces of the flexible substrate 101. Moreover, the first blind hole 201 does not penetrate the first copper layer 102 on the lower surface of the flexible substrate 101, so that the first conductive copper layer 301 can be conveniently set through the first copper layer 102 on the lower surface, preventing the first conductive copper layer 301 from protruding from the first copper layer 102 on the lower surface.

[0048] Furthermore, the second blind via 202 extends from the second copper layer 504 through the dielectric layer 503 to the first copper layer 102. The depth of the second blind via 202 is the distance from the upper surface of the second copper layer 504 to the upper surface of the first copper layer 102 or from the lower surface of the second copper layer 504 to the lower surface of the first copper layer 102. This allows the first copper layer 102 and the second copper layer 504 to be electrically connected after the second conductive copper layer 302 is electroplated in the second blind via 202, thereby achieving conductivity between the first copper layer 102 and the second copper layer 504.

[0049] Combination Figures 3-14 As shown, the dielectric layer 503 is pure adhesive or flowable PP. Specifically, pure adhesive or flowable PP exhibits fluidity under certain high temperature and high pressure conditions, allowing the dielectric layer 503 to fill the gaps between the inner layer circuits 401. After curing, the pure adhesive or flowable PP firmly bonds the flexible core board 10 to the upper outer core board 501 and to the lower outer core board 502, preventing warping of the printed circuit board 100. Simultaneously, the pure adhesive or flowable PP also possesses excellent insulation properties, preventing short circuits between the flexible core board 10 and the upper outer core board 501 and to the lower outer core board 502, thus improving the stability and reliability of the printed circuit board 100. Here, PP refers to prepreg.

[0050] Combination Figures 1-2 and Figures 6-12As shown, before the step of adding an upper outer core board 501 and a lower outer core board 502 to the upper and lower surfaces of the flexible core board 10, the method further includes: attaching micro-adhesive films to the upper and lower surfaces of the flexible core board 10, wherein the micro-adhesive films correspond to the openings of the first copper layer 102 on the first substrate portion 1011.

[0051] Specifically, the micro-adhesive film has low adhesion and is easy to peel off. Before adding the upper outer core board 501 and the lower outer core board 502 to the upper and lower surfaces of the flexible core board 10, respectively, the micro-adhesive film is attached to the opening portion of the first copper layer 102 on the first substrate portion 1011. In this way, during the fabrication of the printed circuit board 100, the stability of the flexible core board 10 and the outer core board can be ensured, while preventing the opening portion of the first copper layer 102 on the first substrate portion 1011 from being firmly bonded to the dielectric layer 503 and difficult to separate. This facilitates the subsequent cutting operation of the opening portion of the first copper layer 102 on the first substrate portion 1011.

[0052] In some embodiments of the present invention, by using the cover film 70 and the solder resist ink windowing process, the copper layer can be exposed at any position on the upper and lower surfaces of the printed circuit board 100 to form solder pads, thereby allowing components to be soldered to the corresponding solder pad positions on the printed circuit board 100.

[0053] In some embodiments of the present invention, the relevant markings on the printed circuit board 100 are usually printed on solder resist ink. The production of the relevant markings needs to be completed before the step of at least partially cutting away the portion of the first substrate portion 1011 of the flexible substrate 101 corresponding to the opening of the first copper layer 102, so as to prevent the printed circuit board 100 from deforming after production, which would make the production of the relevant markings difficult.

[0054] In some embodiments of the present invention, when mounting devices onto the upper and lower surfaces of the printed circuit board 100, the device misalignment problem can be solved by using a fixture and groove for limiting and fixing. Since the printed circuit board 100 uses a flexible core board 10 and includes a first substrate portion 1011 and a second substrate portion 1012 that can independently generate displacement, a certain displacement or deformation can occur in a local area of ​​the printed circuit board 100. After the device is mounted, the fixture is removed, the constraint is released, and the area where the device is located can independently change shape, thereby improving the assembly accuracy and assembly efficiency of the device. The fixture can be a clamp.

[0055] According to the printed circuit board 100 of the present invention, the above-described manufacturing method of the printed circuit board 100 is applicable. Specifically, since the manufacturing method of the printed circuit board 100 is more reliable, the strip structure can be flexibly connected to the second substrate portion 1012, and the strip structure of the first substrate portion 1011 can be displaced to solve the problem of micro-deformation caused by force. By using the manufacturing method of the printed circuit board 100 to manufacture the printed circuit board 100, not only can the stability and reliability of the printed circuit board 100 be improved, but the volume of the printed circuit board 100 can also be reduced through the overall material selection and structural design of the printed circuit board 100.

[0056] 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.

[0057] 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.

[0058] 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, Includes the following steps: Prepare a flexible core board (10), wherein the flexible core board (10) includes a flexible substrate (101) and a first copper layer (102), the flexible substrate (101) has an upper surface and a lower surface disposed opposite to each other in a first direction, and the first copper layer (102) is disposed on the upper surface and the lower surface of the flexible substrate (101). A first blind hole (201) is formed on the flexible core board (10), and a first conductive copper layer (301) is electroplated in the first blind hole (201). The first conductive copper layer (301) in the first blind hole (201) is electrically connected to the first copper layer (102) on the upper and lower surfaces of the flexible substrate (101). Holes are made in the first copper layer (102) on the upper and lower surfaces of the flexible core board (10) to fabricate inner layer circuitry (401). An upper outer core board (501) and a lower outer core board (502) are respectively added to the upper and lower surfaces of the flexible circuit board core board (10). The upper outer core board (501) and the lower outer core board (502) both include a dielectric layer (503) and a second copper layer (504). One side of the dielectric layer (503) in the first direction is in contact with the flexible circuit board core board (10), and the second copper layer (504) is disposed on the other side of the dielectric layer (503) in the first direction. A second blind hole (202) is formed in the second copper layer (504) of both the upper outer core plate (501) and the lower outer core plate (502), and a second conductive copper layer (302) is electroplated in the second blind hole (202), wherein the second conductive copper layer (302) is electrically connected to the first conductive copper layer (301); The first portion (5041) of the second copper layer (504) of the upper outer core board (501) and the lower outer core board (502) is removed, and a hole is made in the second portion (5042) to make an outer layer circuit (402). The second copper layer (504) of the upper outer core board (501) and the lower outer core board (502) includes a first portion (5041) and a second portion (5042) arranged in a left-right direction. Remove the portions of the upper outer core plate (501) and the lower outer core plate (502) that correspond to the first portion (5041); At least a portion of the first substrate portion (1011) of the flexible substrate (101) corresponding to the opening of the first copper layer (102) is cut away. The flexible substrate (101) includes a first substrate portion (1011) and a second substrate portion (1012) arranged in a left-right direction. The first substrate portion (1011) corresponds to the first portion (5041), and the second substrate portion (1012) corresponds to the second portion (5042). The first conductive copper layer (301) is located in the second substrate portion (1012), and the second conductive copper layer (302) is located in the second portion (5042). The middle region in the front-back direction of the portion of the first substrate portion (1011) corresponding to the opening of the first copper layer (102) is removed, while the two end regions in the front-back direction of the portion of the first substrate portion (1011) corresponding to the opening of the first copper layer (102) are retained.

2. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The flexible substrate (101) is a polyimide film.

3. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The step of removing the first portion (5041) of the second copper layer (504) of the upper outer core board (501) and the lower outer core board (502) and making a hole in the second portion (5042) to fabricate the outer layer circuit (402), wherein the second copper layer (504) of the upper outer core board (501) and the lower outer core board (502) includes the first portion (5041) and the second portion (5042) arranged in a left-right direction, further includes: A first solder resist ink (601) is applied at the opening of the second copper layer (504) in the second part (5042).

4. The method for manufacturing a printed circuit board according to claim 3, characterized in that, The step of applying solder resist ink at the opening of the second copper layer (504) in the second part (5042) further includes: Meanwhile, a second solder resist ink (602) is provided on the second conductive copper layer (302) and the second copper layer (504) connected to the second conductive copper layer (302). The thickness of the first solder resist ink (601) in the vertical direction is greater than the thickness of the second copper layer (504) in the vertical direction. The second solder resist ink (602) is flush with the first solder resist ink (601).

5. The method for manufacturing a printed circuit board according to claim 4, characterized in that, The step of removing the portions of the upper outer core plate (501) and the lower outer core plate (502) corresponding to the first portion (5041) includes: A cover film (70) is provided on the second copper layer (504) of the second portion (5042) of the upper outer core plate (501) and the lower outer core plate (502), the cover film (70) being flush with the first solder resist ink (601) and / or the second solder resist ink (602).

6. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The first blind via (201) extends from the first copper layer (102) on the upper surface through the flexible substrate (101) and reaches the first copper layer (102) on the lower surface; and / or the second blind via (202) extends from the second copper layer (504) through the dielectric layer (503) and reaches the first copper layer (102).

7. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The medium layer (503) is pure rubber or liquid PP.

8. The method for manufacturing a printed circuit board according to claim 1, characterized in that, Before the step of adding an upper outer core plate (501) and a lower outer core plate (502) to the upper and lower surfaces of the flexible core plate (10) respectively, the following steps are also included: Micro-adhesive films are respectively attached to the upper and lower surfaces of the flexible core board (10), wherein the micro-adhesive films correspond to the openings of the first copper layer (102) on the first substrate portion (1011).

9. A printed circuit board, characterized in that, The method of manufacturing a printed circuit board applicable to any one of claims 1-8.

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