Circuit board and electronic device

Abstract

The utility model relates to the microelectronic manufacturing technology field, concretely provides a kind of circuit board and electronic equipment, the circuit board includes: substrate;Insulating adhesive layer is set in the target surface of substrate, insulating adhesive layer is equipped with circuit groove, the depth-width ratio of circuit groove is greater than 2:1, interline structural adhesive is formed between adjacent circuit grooves, the minimum width of interline structural adhesive is less than 10 μm, and wire is equipped in circuit groove.Break through the circuit size limit of relevant circuit board, with higher wiring space utilization, it is favorable to reduce the size or layer number of circuit board, can simplify circuit board structure, reduce manufacturing process complexity.To solve the problem that relevant circuit board is difficult to achieve high-precision requirement of high depth-width ratio, narrow line distance.

Description

Technical Field

[0001] This utility model relates to the field of microelectronics manufacturing technology, and in particular to a circuit board and electronic device. Background Technology

[0002] The development of electronic products is trending towards high frequency, high integration, and high-density interconnection, which requires electronic product circuit boards to develop towards high aspect ratios and narrow line spacing. However, the line spacing and line width of related circuit boards are usually greater than 50μm, and the aspect ratio is difficult to exceed 1:1, which cannot meet the needs of high-precision manufacturing.

[0003] There is currently no effective solution to the problem that related circuit boards cannot meet the high precision requirements of high aspect ratio and narrow line spacing. Utility Model Content

[0004] The present invention provides a circuit board and electronic device that at least solves the problem that related circuit boards are difficult to meet the high precision requirements of high aspect ratio and narrow line spacing.

[0005] This utility model embodiment provides a circuit board, including: a substrate; an insulating adhesive layer disposed on a target surface of the substrate, the insulating adhesive layer having circuit trenches, the aspect ratio of the circuit trenches being greater than 2:1, an inter-line structural adhesive forming between adjacent circuit trenches, the minimum width of the inter-line structural adhesive being less than 10μm, and conductors disposed within the circuit trenches.

[0006] The circuit board provided in this embodiment of the utility model has a line trench with a depth-to-width ratio greater than 2:1 and less than or equal to 5:1, a minimum line trench width range of 1μm-10μm, and a line trench depth range of 5μm-70μm.

[0007] The circuit board provided in this embodiment of the utility model has an insulating adhesive layer with a UV-curable polymer composite adhesive. The dielectric constant of the adhesive is ≤3.5 and the dielectric loss is ≤0.003@10GHz.

[0008] The circuit board provided in this embodiment of the utility model has a maximum height roughness of ≤50nm for the sidewall of the line trench and a maximum height roughness of <1μm for the sidewall of the conductor.

[0009] The circuit board provided in this embodiment of the utility model has a rectangular groove, a trapezoidal groove, or a groove with an arc-shaped sidewall; the surface of the conductor away from the substrate is recessed relative to the surface of the insulating adhesive layer away from the substrate, or protrudes relative to the surface of the insulating adhesive layer away from the substrate, or is flush with the surface of the insulating adhesive layer away from the substrate.

[0010] The circuit board provided in this embodiment of the utility model has wires covering the inner surface of the circuit trenches, and the wires are metal wires.

[0011] The circuit board provided in this embodiment of the utility model has copper wires as conductors, and the thickness uniformity of the copper wires is ±10%.

[0012] The circuit board provided in this embodiment of the utility model has a rigid substrate or a flexible substrate as the substrate, and a roughening treatment layer is provided on the target surface of the substrate, and an insulating adhesive layer is disposed on the roughening treatment layer.

[0013] The circuit board provided in this embodiment of the utility model is a circuit board with a conductor count of 400-600 lines / mm² per unit area.

[0014] This utility model embodiment also provides an electronic device, including a power supply, a controller, a load, and any of the above-mentioned circuit boards, wherein the power supply supplies power to the load through the circuit board, and the controller controls the load through the circuit board.

[0015] This utility model provides a circuit board and electronic device. The circuit board has a depth-to-width ratio (DVR) of greater than 2:1 for its wiring trenches and a minimum width of less than 10 μm for the inter-line structural adhesive. This means the circuit board achieves high precision requirements for high DVR and narrow line spacing, overcoming the limitations of existing circuit board dimensions. It meets the urgent needs of high-frequency communication, integrated circuit packaging, and high-density interconnect circuit board fields for circuit boards with high DVR and narrow line spacing. It also boasts high wiring space utilization, which helps reduce the size or number of layers of the circuit board, simplifies the circuit board structure, and reduces manufacturing complexity. This solves the problem of existing circuit boards struggling to achieve the high precision requirements for high DVR and narrow line spacing. Attached Figure Description

[0016] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0017] Figure 1 This is a cross-sectional schematic diagram of a circuit board according to an embodiment of this utility model.

[0018] Figure 2 This is a schematic diagram of a trapezoidal trench in an embodiment of this utility model.

[0019] Figure 3 This is a schematic diagram of an embodiment of the present invention where the line trench is an inverted trapezoidal trench.

[0020] Figure 4 This is a schematic diagram of a groove with arc-shaped sidewalls in an embodiment of this utility model.

[0021] Figure 5 This is a schematic diagram of a module of an electronic device according to an embodiment of this utility model.

[0022] The above figures include the following reference numerals:

[0023] 1—Substrate; 2—Insulating adhesive layer; 20—Circuit trench; D—Circuit trench depth; W—Minimum width of circuit trench; d—Minimum width of inter-line structural adhesive. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0027] Please refer to Figure 1 The schematic diagram of the circuit board cross-section shown illustrates that this embodiment of the invention provides a circuit board including a substrate 1 and an insulating adhesive layer 2. The insulating adhesive layer 2 is disposed on the target surface of the substrate 1, and circuit trenches 20 are provided on the insulating adhesive layer 2. The depth-to-width ratio (D / W) of the circuit trenches 20 is greater than 2:1. Inter-line structural adhesive is formed between adjacent circuit trenches 20, and the minimum width (d) of the inter-line structural adhesive is less than 10 μm. Conductors are provided within the circuit trenches 20.

[0028] Substrate 1 can be a rigid substrate or a flexible substrate, as will be described later.

[0029] Either side of the substrate 1 can be used as the target surface, or both sides of the substrate 1 can be used as the target surface. Those skilled in the art can select and adapt the target surface according to the actual situation. This embodiment Figure 1 The circuit board shown uses only one side of substrate 1 as the target surface.

[0030] The line trench 20 is preferably obtained by imprinting the insulating adhesive layer 2 using an imprinting mold, and the shape of the line trench 20 corresponds to the line pattern on the imprinting mold. On the one hand, it has the advantages of simple process, low cost, mass production capability and high pattern resolution, which helps to reduce manufacturing costs; on the other hand, the sidewalls of the line prepared by imprinting are smooth, avoiding the problem of increased sidewall roughness caused by etching process, which can improve the transmission performance of high frequency signals.

[0031] Without considering the increase in sidewall roughness, those skilled in the art can use etching processes to fabricate the aforementioned circuit board. Of course, those skilled in the art can also use other processes besides imprinting and etching to fabricate the aforementioned circuit board, and are not limited thereto.

[0032] The insulating adhesive layer 2 is obtained by uniformly coating structural adhesive onto the target surface of the substrate 1. The structural adhesive can be, but is not limited to, UV adhesive, ABF adhesive, or thermosetting resin. In this embodiment, UV adhesive is preferred, as it has the advantages of faster curing speed and better release properties, which will be described in detail later.

[0033] The insulating adhesive layer 2 is used to provide the wiring trench 20, which forms the conductive lines of the circuit board after being filled with wires. It is understood that the thickness of the insulating adhesive layer 2 needs to be greater than the depth of the wiring trench 20. For example, the thickness of the insulating adhesive between the bottom of the wiring trench 20 and the substrate 1 is 2μm-50μm.

[0034] The depth-to-width ratio (D / W) of the line trench 20 is greater than 2:1, which can increase the effective cross-sectional area of ​​the conductor, optimize the heat dissipation path of the conductor, and reduce capacitive coupling and crosstalk between conductors; it can also enhance the wrapping properties of the insulating layer 2 on the conductor and improve the adhesion between the conductor and the insulating layer 2.

[0035] The minimum width d of the inter-line structural adhesive is less than 10μm, such as 5μm or 7μm, which can increase the wiring capacity per unit area and facilitate the miniaturization of electronic devices; it can also enhance the parallel signal transmission capability while reducing material loss.

[0036] The conductor can be a metallic conductor, such as gold, silver, copper, or aluminum conductor; an alloy conductor, such as copper-nickel conductor; or a conductor made of organic conductive materials or conductive metal oxides, such as ITO. Obviously, those skilled in the art can use conductors made of other materials according to actual needs.

[0037] In summary, the circuit board provided by this invention has a trench aspect ratio greater than 2:1 and a minimum width of the inter-line structural adhesive of less than 10μm. This means the circuit board achieves high precision requirements for high aspect ratio and narrow line spacing, overcoming the limitations of related circuit board dimensions. It meets the urgent needs of high aspect ratio and narrow line spacing circuit boards in high-frequency communication, integrated circuit packaging, and high-density interconnect circuit board fields. It also boasts high wiring space utilization, which helps reduce the size or number of layers of the circuit board, simplifies the circuit board structure, and reduces manufacturing complexity. This solves the problem of related circuit boards struggling to achieve high precision requirements for high aspect ratio and narrow line spacing.

[0038] Preferably, the thickness of the insulating adhesive layer is 15μm-80μm, the depth-to-width ratio of the line trench is greater than 2:1 and less than or equal to 5:1, the minimum width of the line trench is 1μm-10μm, and the depth of the line trench is 5μm-70μm.

[0039] A depth-to-width ratio greater than 2:1 ensures that the depth-to-width ratio of the wiring trench 20 is not too low, guaranteeing high utilization of wiring space and structural support. An upper limit of 5:1 ensures that the depth-to-width ratio of the wiring trench 20 is not too high, reducing the difficulty of demolding structural adhesive and filling wires, thereby improving production efficiency while reducing the risk of stress concentration.

[0040] Furthermore, the depth-to-width ratio of the trench 20 is 3:1. Of course, this is not a limitation.

[0041] For example, taking a substrate with a size of 10mm×10mm, an insulating adhesive layer with a thickness of 40μm, a line trench width of 10μm, and an inter-line structural adhesive width of 5μm as an example, we compare circuit boards with line trench depth-to-width ratios of 2:1 and 3:1, respectively.

[0042] Both the 2:1 and 3:1 aspect ratio trenches can accommodate 667 lines laterally. However, the 2:1 aspect ratio trench has a depth of 20 μm, while the 3:1 aspect ratio trench has a depth of 30 μm. Obviously, the 3:1 aspect ratio trench has a higher longitudinal space utilization rate.

[0043] In addition, the distance between the line trench with a depth-to-width ratio of 2:1 and the bottom of the insulating layer is 20μm, while the distance between the line trench with a depth-to-width ratio of 3:1 and the bottom of the insulating layer is 10μm. It can be seen that the circuit board with a depth-to-width ratio of 3:1 is more compact in structure and can avoid deformation caused by insufficient line support due to excessively thick insulating layer.

[0044] It should be noted that the above example data are approximate values. Furthermore, since achieving an aspect ratio of 2:1 on circuit boards manufactured using related technologies is already quite difficult, the improvements in wiring space utilization and structural support resulting from an aspect ratio greater than 2:1 are greater than those shown in the example data.

[0045] Preferably, the structural adhesive of the insulating layer is a UV-curable polymer composite adhesive. For example, a modified acrylate composite adhesive or an epoxy resin composite adhesive. The dielectric constant (Dk) of the above structural adhesive is ≤3.5, and the dielectric loss (Df) is ≤0.003@10GHz, which can meet the requirements of high-frequency signal transmission.

[0046] Preferably, the maximum height roughness Rz of the sidewall profile of the line trench is ≤50nm, and the maximum height roughness Rz of the sidewall profile of the conductor is <1μm.

[0047] As can be seen, in the circuit board provided in this embodiment, the maximum height roughness of the sidewall profile of the circuit trench is close to that of a mirror surface, which can significantly reduce the skin effect loss of high-frequency signals. At the same time, the low sidewall roughness of the circuit trench helps to reduce the sidewall roughness of the conductors, further improving the performance of the circuit board.

[0048] Preferably, the wiring trench is a rectangular trench, a trapezoidal trench, or a trench with arc-shaped sidewalls. The surface of the conductor away from the substrate is either recessed relative to the surface of the insulating adhesive layer away from the substrate, or protruding relative to the surface of the insulating adhesive layer away from the substrate, or flush with the surface of the insulating adhesive layer away from the substrate.

[0049] For example, Figure 1 The line trench 20 shown is a rectangular trench, which has the advantages of convenient design and processing, high space utilization, uniform electric field distribution, and easy integration of wires with other electronic components.

[0050] Figure 2 The trench 20 shown is a trapezoidal trench, which has strong structural stability.

[0051] Figure 3 The groove 20 shown is an inverted trapezoidal groove, which facilitates demolding.

[0052] Figure 4 The line trench 20 shown is a trench with arc-shaped sidewalls, which has strong fatigue resistance.

[0053] The surface of the conductive wires away from the substrate 1 is flush with the surface of the insulating layer 2, which is also away from the substrate 1. This helps the insulating layer 2 to effectively protect the conductive wires, preventing them from being corroded, worn, or oxidized by the external environment, thereby extending the lifespan of the circuit board. The flush surface ensures that the insulating layer 2 forms a complete and uniform insulating layer around the conductive wires, improving the insulation performance and safety of the circuit. The flush surface also helps to improve the accuracy and reliability of mounting electronic components on the circuit board, reducing the occurrence of problems such as poor soldering and short circuits.

[0054] Preferably, the conductor covers the inner surface of the trench, and the conductor is a metal conductor.

[0055] The conductor covering the inner surface of the wiring trench means that the conductor filling the wiring trench 20 is fully fitted to the trench 20. This makes full use of the space provided by the wiring trench 20, which helps to achieve dense wiring within a limited circuit board space and meets the development needs of high-density interconnection of circuit boards. At the same time, the full fit between the conductor and the wiring trench ensures that the conductor can be well fixed in the corresponding wiring trench 20 when subjected to external impact or vibration, making it less likely to shift or fall off. This improves the mechanical strength and reliability of the circuit board and reduces circuit failures caused by loose conductors.

[0056] The conductor is a metallic conductor, such as a copper conductor, which has high electrical conductivity, thermal conductivity, and mechanical strength. It is also relatively inexpensive and has good compatibility with other metallic or non-metallic materials, making it less prone to severe electrochemical corrosion problems during electrical connections. In this embodiment, a copper conductor with a thickness uniformity of ±10% is preferably used.

[0057] Preferably, the substrate is a rigid substrate or a flexible substrate.

[0058] The rigid substrate can be, but is not limited to, FR-4 substrate or BT resin substrate.

[0059] Flexible substrates can be, but are not limited to, PI substrates, LCP substrates, PET substrates, PC substrates, and PMMA substrates.

[0060] Preferably, the target surface of the substrate is provided with a roughening layer, and the insulating adhesive layer is disposed on the roughening layer.

[0061] The roughening layer described above is obtained by roughening the target surface of the substrate, which can enhance the adhesion of the structural adhesive of the insulating layer to the substrate. For example, the roughness Ra of the roughening layer is 1~3μm.

[0062] Preferably, the circuit board provided in this embodiment has a conductor count of 400-600 lines / mm², which can improve wiring density by 3-5 times and line spacing resolution by 5 times compared to the circuit board with a minimum width of 50μm for the inter-line structural adhesive prepared by related technologies.

[0063] Please refer to Figure 5 The schematic diagram of the module shown in the present invention also provides an electronic device, including a power supply 100, a controller 200, a load 300, and any of the aforementioned circuit boards 400, wherein the power supply 100 supplies power to the load 300 through the circuit board 400, and the controller 200 controls the load 300 through the circuit board 400.

[0064] It is understood that the above-described electronic device has all the beneficial effects of the circuit board provided in the above embodiments, and will not be described again in this embodiment.

[0065] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0066] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0067] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A circuit board, characterized in that, include: substrate; An insulating adhesive layer is disposed on the target surface of the substrate. The insulating adhesive layer has circuit trenches with a depth-to-width ratio greater than 2:

1. An inter-line structural adhesive is formed between adjacent circuit trenches. The minimum width of the inter-line structural adhesive is less than 10 μm. A conductor is disposed within the circuit trench.

2. The circuit board according to claim 1, characterized in that, The aspect ratio of the line trench is greater than 2:1 and less than or equal to 5:1, the minimum width of the line trench is 1μm-10μm, and the depth of the line trench is 5μm-70μm.

3. The circuit board according to claim 1, characterized in that, The structural adhesive of the insulating layer is a UV-curable polymer composite adhesive, and the dielectric constant of the structural adhesive is ≤3.5 and the dielectric loss is ≤0.003@10GHz.

4. The circuit board according to claim 1, characterized in that, The maximum height roughness of the sidewall profile of the line trench is ≤50nm, and the maximum height roughness of the sidewall profile of the conductor is <1μm.

5. The circuit board according to claim 1, characterized in that, The circuit trench is a rectangular trench, a trapezoidal trench, or a trench with arc-shaped sidewalls; the surface of the conductor away from the substrate is either recessed relative to the surface of the insulating adhesive layer away from the substrate, or protruding relative to the surface of the insulating adhesive layer away from the substrate, or flush with the surface of the insulating adhesive layer away from the substrate.

6. The circuit board according to claim 1 or claim 5, characterized in that, The conductor covers the inner surface of the line trench, and the conductor is a metal conductor.

7. The circuit board according to claim 1, characterized in that, The conductor is a copper conductor, and the thickness uniformity of the copper conductor is ±10%.

8. The circuit board according to claim 1, characterized in that, The substrate is a rigid substrate or a flexible substrate, and the target surface of the substrate is provided with a roughening layer, and the insulating adhesive layer is disposed on the roughening layer.

9. The circuit board according to claim 1, characterized in that, The circuit board is a circuit board with 400-600 wires / mm² per unit area.

10. An electronic device, characterized in that, The electronic device includes a power supply, a controller, a load, and a circuit board according to any one of claims 1 to 9, wherein the power supply supplies power to the load through the circuit board, and the controller controls the load through the circuit board.

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