Circuit board and preparation method thereof
By forming a first line layer in the line groove on the insulating layer, and setting a second line layer across the surface and isolating it, the problems of wiring density and thickness in the prior art are solved, and the thinner and flexible layout of the circuit board is realized.
Patent Information
- Application Number
- CN202410098702.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-24
- Publication Date
- 2025-07-25
AI Technical Summary
The prior art is difficult to improve the wiring density and reduce the thickness of printed circuit boards, and it is difficult to meet the requirements of electronic products to develop in the direction of lightness, shortness and multifunctionality.
A line groove is formed on the insulating layer, and a first line layer is buried in the groove, a second line layer is arranged at the surfaces at the intersection, and a thin insulating film is used for electrical isolation to realize the stacking of double-layer lines.
It improves the line layout density, increases space utilization, reduces the board thickness, is conducive to the lightness and thinness of the board, and reduces the line spacing, improving layout flexibility.
Smart Images
Figure CN120379130A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of printed circuit boards, and particularly to a circuit board and a method for manufacturing the same. Background Art
[0002] With the development of large-scale integrated circuits, in the field of printed circuit board (PCB) manufacturing technology, there is a PCB build-up process. The so-called PCB build-up process is based on a double-sided or four-sided circuit board, adopting the concept of successive lamination, and successively adding circuit layers outside the board. This process includes inner-layer pattern making, first lamination, outer-layer pattern making, second lamination, drilling, electroplating, etc., so as to achieve the build-up of the PCB.
[0003] Currently, electronic products are increasingly developing towards being thinner, lighter, shorter, and more multifunctional, which puts higher requirements on the PCB wiring density in electronic products. However, for the multi-layer circuit board formed by the aforementioned build-up process, it is difficult to improve the wiring density, and the overall thickness of the PCB is relatively large, making it difficult to meet the requirements. Summary of the Invention
[0004] In view of this, in order to solve at least one of the above problems, this application is necessary to provide a circuit board.
[0005] In addition, this application is also necessary to provide a method for manufacturing the aforementioned circuit board.
[0006] An embodiment of this application provides a circuit board, which includes: an insulating layer, a first circuit layer, and a second circuit layer. The insulating layer includes a first surface and a second surface arranged opposite to each other. A circuit groove is formed by the first surface recessing towards the second surface; the first circuit layer is disposed in the circuit groove; the second circuit layer is disposed on the first surface and intersects with the first circuit layer, and an insulating film is provided between the first circuit layer and the second circuit layer at the intersection.
[0007] In some possible embodiments, along the thickness direction of the circuit board, the depth of the circuit groove is greater than the thickness of the first circuit layer.
[0008] In some possible embodiments, the insulating film is located in the circuit groove, and the surface of the insulating film facing away from the first circuit layer is flush with the first surface.
[0009] In some possible embodiments, the insulating film is provided on the surface of the first circuit layer.
[0010] In some possible embodiments, a conduction post penetrating the insulating film is further provided at the intersection, and the first circuit layer and the second circuit layer are electrically connected through the conduction post.
[0011] In some possible embodiments, an inner substrate is provided on the second surface, and the inner substrate includes at least one circuit layer.
[0012] The embodiment of the present application further provides a method for manufacturing a circuit board, and the method includes:
[0013] Form a circuit groove on the insulating layer, the insulating layer includes a first surface and a second surface which are oppositely arranged, and the circuit groove is recessed from the first surface towards the second surface;
[0014] Form a first circuit layer in the circuit groove;
[0015] Form an insulating film on the surface of the first circuit layer; and
[0016] Form a second circuit layer on the first surface and the surface of the insulating film, so that the second circuit layer and the first circuit layer are arranged in a cross manner.
[0017] In some possible embodiments, the method for manufacturing the first circuit layer includes:
[0018] Provide a circuit substrate, the circuit substrate includes the insulating layer and a first metal layer, and the first metal layer is located on the first surface of the insulating layer;
[0019] Form an opening through the first metal layer, and the first surface is exposed by the opening;
[0020] Remove a part of the insulating layer exposed by the opening to form the circuit groove;
[0021] Form a conductive layer in the circuit groove and the opening; and
[0022] Remove the first metal layer, the conductive layer located in the opening and a part of the conductive layer located in the circuit groove, so that the remaining conductive layer forms the first circuit layer.
[0023] In some possible embodiments, the insulating film is formed on a partial surface of the first circuit layer by spraying an insulating medium.
[0024] In some possible embodiments, the insulating film is located in the circuit groove, and the surface of the insulating film facing away from the first circuit layer is flush with the first surface.
[0025] Compared with the prior art, the circuit board and its manufacturing method provided by the embodiments of the present application can achieve the effect of forming a double-layer circuit stacked on one insulating layer by embedding the first circuit layer in the insulating layer, then forming a second circuit layer that intersects and overlaps with the first circuit layer on the surface of the insulating layer, and using an insulating film with a relatively thin thickness for electrical isolation at the intersection. This effectively improves the circuit layout density, increases the space utilization rate of the circuit board, and reduces the overall thickness of the circuit board, which is beneficial to the thinning of the circuit board. In addition, by adopting the above cross-wiring method, the circuit pitch can be reduced, circuit detours can be reduced, and the flexibility of the circuit layout can be improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 FIG. is a top view of a circuit board provided by an embodiment of the present application.
[0027] Figure 2 is Figure 1 A schematic cross-sectional structure diagram of the intersection A in FIG. along II-II.
[0028] Figure 3 is Figure 1 A schematic cross-sectional structure diagram of the intersection B in FIG. along III-III.
[0029] Figure 4 FIG. is a flowchart of a manufacturing method of a circuit board provided by an embodiment of the present application.
[0030] Figures 5A to 5K FIG. is a schematic structural diagram of the manufacturing process of a circuit board provided by an embodiment of the present application.
[0031] MAIN ELEMENT SYMBOL DESCRIPTION
[0032] Circuit board 100
[0033] Insulating layer 1
[0034] First surface 11
[0035] Second surface 12
[0036] Line groove 13
[0037] First circuit layer 2
[0038] Second circuit layer 3
[0039] Insulating film 4
[0040] Inner layer substrate 5
[0041] Conducting post 6
[0042] Circuit substrate 10
[0043] First metal layer 20
[0044] Dry film 30
[0045] Conductive layer 40
[0046] Second metal layer 50
[0047] Intersections A, B
[0048] Depth H1
[0049] Thickness H2
[0050] Line width L1
[0051] Width L2
[0052] Thickness direction Z
[0053] Width direction Y
[0054] The following specific embodiments will further illustrate the present application in conjunction with the above drawings. Specific embodiments
[0055] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.
[0056] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element at the same time.
[0057] Please refer to Figures 1 to 3 , an embodiment of the present application provides a circuit board 100, and the circuit board 100 includes an insulating layer 1, a first circuit layer 2, and a second circuit layer 3. The insulating layer 1 includes a first surface 11 and a second surface 12 that are oppositely arranged, and a circuit groove 13 is formed by the first surface 11 recessing towards the second surface 12. The first circuit layer 2 is disposed in the circuit groove 13. The second circuit layer 3 is disposed on the first surface 11 and intersects with the first circuit layer 2, and an insulating film 4 is provided between the first circuit layer 2 and the second circuit layer 3 at the intersection (such as Figure 1 A and B in
[0058] In some embodiments, along the thickness direction Z of the circuit board 100, the depth H1 of the circuit groove 13 is greater than the thickness H2 of the first circuit layer 2, so that the first circuit layer 2 is embedded in the insulating layer 1.
[0059] In some embodiments, the insulating film 4 is filled in a part of the circuit groove 13. Along the width direction Y of the first circuit layer 2, the width L2 of the insulating film 4 is equal to the line width L1 of the first circuit layer 2, and the first circuit layer 2 can be completely covered, so that accidental connection will not occur when the second circuit layer 3 is manufactured, ensuring the electrical isolation between the first circuit layer 2 and the second circuit layer 3.
[0060] In some embodiments, the surface of the insulating film 4 facing away from the first circuit layer 2 is flush with the first surface 11, so that the flatness of the second circuit layer 3 located on the first surface 11 and the second circuit layer 3 located at the intersection A (B) is better, and the thickness of the second circuit layer 3 is more uniform.
[0061] In some embodiments, as Figure 3 shown, if necessary, when the first circuit layer 2 and the second circuit layer 3 need to be electrically connected, a conduction post 6 can be provided through the insulating film 4 at the intersection B, for example, so that the first circuit layer 2 and the second circuit layer 3 are electrically connected through the conduction post 6.
[0062] In some embodiments, a second circuit layer 3 can be cross-stacked above the first circuit layer 2, and the same cross-stacking method can also be used to cross-stack multiple second circuit layers above the first circuit layer 2.
[0063] It can be understood that an inner layer substrate 5 can also be provided on the second surface 12 of the insulating layer 1, and the inner layer substrate 5 can include one circuit layer or multiple circuit layers.
[0064] It can also be understood that an additional layer can be added above the second circuit layer 3, so that the circuit board 100 can achieve more functions.
[0065] Please refer to Figure 4 and, in combination with Figures 5A to 5K , the embodiments of the present application also provide a preparation method for the foregoing circuit board 100, and the preparation method includes the following steps:
[0066] Step S1, as Figures 5A to 5E shown, a circuit groove 13 is formed on the insulating layer 1. The insulating layer 1 includes a first surface 11 and a second surface 12 which are oppositely arranged, and the circuit groove 13 is recessed from the first surface 11 towards the second surface 12.
[0067] Specifically, the step S1 includes the following steps:
[0068] Step S11, as Figure 5A shown, provide a circuit board 10, the circuit board 10 includes the insulating layer 1 and a first metal layer 20, wherein, the first metal layer 20 is located on the first surface 11 of the insulating layer 1.
[0069] In some embodiments, the material of the insulating layer 1 may be epoxy resin, prepreg (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) and other resins.
[0070] Step S12, as Figures 5B to 5D shown, form an opening 21 through the first metal layer 20, and part of the first surface 11 is exposed by the opening 21.
[0071] Specifically, the opening 21 can be formed on the first metal layer 20 by means of covering a dry film 30, exposure, development, etching, and stripping the film.
[0072] Step S13, as Figure 5E shown, remove part of the insulating layer 1 exposed by the opening 21 to form the line groove 13 on the insulating layer 1.
[0073] Specifically, part of the insulating layer 1 can be removed by physical or chemical etching to form the line groove 13.
[0074] Step S2, as Figures 5F to 5G shown, form a first circuit layer 2 in the line groove 13.
[0075] Specifically, the step S2 includes the following steps:
[0076] Step S21, as Figure 5F shown, form a conductive layer 40 in the line groove 13 and the opening 21. For example, the conductive layer 40 can be formed in the line groove 13 and the opening 21 by horizontal or vertical electroplating.
[0077] Step S22, as Figure 5GAs shown, the first metal layer 20, the conductive layer 40 within the opening 21, and the conductive layer 40 partially within the line groove 13 are removed, such that the remaining conductive layer 40 forms the first line layer 2. For example, the first metal layer 20 and part of the conductive layer 40 can be removed by etching, such that the formed first line layer 2 is embedded within the line groove 13.
[0078] Step S3, as Figure 5H shown, an insulating film 4 is formed on the surface of the first line layer 2.
[0079] Specifically, an insulating medium can be sprayed onto the surface of the first line layer 2 by spraying and cured to form the insulating film 4, wherein the insulating film 4 is within the line groove 13. For the flatness and thickness uniformity of the subsequently formed second line layer, the surface of the insulating film 4 is flush with the first surface 11.
[0080] In some embodiments, the insulating medium for forming the insulating film 4 can be a material capable of forming a film by spraying, for example, it can be resins such as epoxy resin, BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).
[0081] Step S4, as Figures 5I to 5K shown, and with reference to Figure 1 collectively, a second line layer 3 is formed on the first surface 11 and part of the surface of the insulating film 4, such that the second line layer 3 intersects with the first line layer 2.
[0082] Specifically, a second metal layer 50 can be formed on the first surface 11 and the surface of the insulating film 4 by horizontal or vertical electroplating, and then the second line layer 3 is formed by processes such as laminating a dry film 30, exposure, development, etching, and stripping the film. In this way, the second line layer 3 is integrally disposed on the first surface 11 of the insulating layer 1 and intersects and overlaps with the first line layer 2. Due to the presence of the insulating film 4 between the first line layer 2 and the second line layer 3 at the intersection A, electrical isolation can be achieved.
[0083] It can be understood that conduction between the first line layer 2 and the second line layer 3 can also be achieved by providing a conduction post 6 penetrating the insulating film 4 at, for example, intersection B (with reference to Figure 3 ).
[0084] It can be understood that the circuit board 10 further includes an inner layer substrate 5 located on the second surface 12 of the insulating layer 1. The inner layer substrate 5 may include a single layer of circuit layer or multiple layers of circuit layers.
[0085] It can also be understood that other circuit layers can be formed on the surface of the second circuit layer 3 by means of layer addition.
[0086] In the circuit board 100 and its manufacturing method provided by the embodiments of the present application, by embedding the first circuit layer 2 in the insulating layer 1, then forming a second circuit layer 3 that intersects and overlaps with the first circuit layer 2 on the surface of the insulating layer 1, and using an insulating film 4 with a relatively thin thickness for electrical isolation at the intersection A, the effect of forming a double-layer circuit that overlaps on a single insulating layer 1 can be achieved, effectively improving the circuit layout density, increasing the space utilization rate of the circuit board 100, and reducing the overall thickness of the circuit board 100, which is beneficial to the thinning of the circuit board 100. In addition, by adopting the above cross-wiring method, the circuit pitch can be reduced, circuit detours can be reduced, and the flexibility of the circuit layout can be improved.
Claims
1. A circuit board, characterized in that, Comprising: An insulating layer, including a first surface and a second surface arranged oppositely, wherein a circuit groove is formed by the first surface being recessed towards the second surface; A first circuit layer, disposed within the circuit groove; A second circuit layer, disposed on the first surface and arranged crosswise with the first circuit layer, and an insulating film is provided between the first circuit layer and the second circuit layer at the crossing point.
2. The circuit board according to claim 1, characterized in that, Along the thickness direction of the circuit board, the depth of the circuit groove is greater than the thickness of the first circuit layer.
3. The circuit board according to claim 1, wherein The insulating film is located within the circuit groove, and the surface of the insulating film facing away from the first circuit layer is flush with the first surface.
4. The circuit board according to claim 1, wherein The insulating film is provided on the surface of the first circuit layer.
5. The circuit board according to claim 1, characterized in that A conducting post penetrating the insulating film is further provided at the crossing point, and the first circuit layer and the second circuit layer are electrically connected through the conducting post.
6. The circuit board according to claim 1, characterized in that, An inner-layer substrate is provided on the second surface, and the inner-layer substrate includes at least one circuit layer.
7. A method for preparing a circuit board, characterized in that, Comprising: Forming a circuit groove on the insulating layer, the insulating layer including a first surface and a second surface arranged oppositely, and the circuit groove is formed by the first surface being recessed towards the second surface; Forming a first circuit layer within the circuit groove; Forming an insulating film on the surface of the first circuit layer; And Forming a second circuit layer on the first surface and the surface of the insulating film, so that the second circuit layer and the first circuit layer are arranged crosswise.
8. The manufacturing method of the circuit board according to claim 7, characterized in that, The preparation method of the first circuit layer includes: Providing a circuit substrate, the circuit substrate including the insulating layer and a first metal layer, and the first metal layer is located on the first surface of the insulating layer; Forming an opening through the first metal layer, and the first surface is exposed by the opening; Removing a part of the insulating layer exposed by the opening to form the circuit groove; Forming a conductive layer within the circuit groove and the opening; and Removing the first metal layer, the conductive layer within the opening, and a part of the conductive layer within the circuit groove, so that the remaining conductive layer forms the first circuit layer.
9. The method for preparing a circuit board according to claim 7, characterized in that, The insulating film is formed on the partial surface of the first circuit layer by spraying an insulating medium.
10. The method for preparing a circuit board according to claim 9, wherein The insulating film is located within the circuit groove, and the surface of the insulating film facing away from the first circuit layer is flush with the first surface.