Circuit board manufacturing method and circuit board

Abstract

The invention provides a manufacturing method of a circuit board. The invention also provides a circuit board, which comprises a circuit substrate, an insulating layer and first aerogel. The circuit substrate comprises a base material layer and a circuit layer located on the surface of the base material layer, and the circuit layer comprises a signal line; the insulating layer is located on the surface of the substrate layer provided with the circuit layer, an opening is formed in the insulating layer, and the signal line is exposed out of the opening; the first aerogel is accommodated in the opening and covers the signal line. According to the circuit board, at least part of the surface of the signal line is covered with the aerogel, the circuit layer is locally coated, signal loss can be reduced, meanwhile, the manufacturing cost can be reduced, and the circuit board is prevented from collapsing in the area where the signal line is located.

Description

Technical Field

[0001] The present application relates to the technical field of circuit boards, and in particular to a method for manufacturing a circuit board and a circuit board. Background Art

[0002] In order to meet the needs of high-frequency signal transmission, circuit boards usually use materials with lower dielectric constants (Dk) and lower dielectric loss factors (Df), such as liquid crystal polymers (LCP) and polytetrafluoroethylene (PTFE). However, the processing performance of the above materials is not as good as that of polyimide (PI). For example, LCP expands and shrinks greatly during the process, which affects the manufacturing accuracy of the product. In addition, the above materials are relatively expensive, and the large-scale introduction of low-loss materials greatly increases the manufacturing cost of the product. In addition, some circuit boards use cavities to reduce line transmission losses, but the formation of cavities in the circuit board is prone to collapse during the pressing process. Summary of the invention

[0003] The present application provides a method for manufacturing a circuit board, comprising the following steps: providing a circuit substrate, the circuit substrate comprising a base material layer and a circuit layer located on the surface of the base material layer, the circuit layer comprising a signal line; covering the surface of the base material layer provided with the circuit layer with an insulating layer having an opening, the signal line being exposed in the opening; covering the opening with a first aerogel solution and curing it to form a first aerogel covering the signal line in the opening.

[0004] In some embodiments, after the step of forming a first aerogel covering the signal line, the manufacturing method further includes: flipping the circuit substrate provided with the first aerogel, forming a first through hole penetrating the substrate layer in the area provided with the signal line, and the surface of the signal line facing away from the first aerogel and the surface of the first aerogel are both exposed to the first through hole; covering the second aerogel solution in the first through hole and curing it to form a second aerogel connected to the first aerogel.

[0005] In some embodiments, before the step of covering the opening with the first aerogel solution, the manufacturing method further includes: forming a second through hole penetrating the substrate layer in an area where the signal line is provided; providing a mold having a groove on a surface of the substrate layer away from the circuit layer, wherein the groove is connected to the second through hole; when covering the opening with the first aerogel solution, the first aerogel solution is also contained in the second through hole and the groove to form a first aerogel in the second through hole and the groove; and removing the mold.

[0006] In some embodiments, along a cross section perpendicular to the extending direction of the circuit substrate, both sides of the groove protrude from the second through hole.

[0007] In some embodiments, before the step of covering the first aerogel solution in the opening, the manufacturing method further includes: forming a second through hole penetrating the substrate layer in the area where the signal line is provided; when covering the first aerogel solution in the opening, the first aerogel solution is also accommodated in the second through hole to form the first aerogel in the second through hole; flipping the circuit substrate provided with the first aerogel, covering the third aerogel solution in the area where the second through hole is provided on the surface of the substrate layer facing away from the circuit layer and solidifying it to form a third aerogel connected to the first aerogel.

[0008] The present application also provides a circuit board, comprising a circuit substrate, an insulating layer and a first aerogel. The circuit substrate comprises a substrate layer and a circuit layer located on the surface of the substrate layer, the circuit layer comprises a signal line; the insulating layer is located on the surface of the substrate layer provided with the circuit layer, an opening is provided on the insulating layer, and the signal line is exposed in the opening; the first aerogel is accommodated in the opening and covers the signal line.

[0009] In some embodiments, a first through hole is formed on the substrate layer, and the signal line is exposed in the first through hole. The circuit board further includes a second aerogel, and the second aerogel is located in the first through hole and connected to the first aerogel.

[0010] In some embodiments, a second through hole is opened on the substrate layer, and the second through hole is located in the area where the signal line is located. The first aerogel is also accommodated in the second through hole and is also located on the surface of the substrate layer away from the circuit layer.

[0011] In some embodiments, a second through hole is opened on the substrate layer, and the second through hole is located in the area where the signal line is located. The circuit board also includes a third aerogel, and the third aerogel is accommodated in the second through hole. The third aerogel is also located on the surface of the substrate layer away from the circuit layer.

[0012] In some embodiments, the width between the edge of the opening and the signal line is greater than 0.2 mm.

[0013] The present application uses aerogel, namely, a first aerogel, a second aerogel and / or a third aerogel, to cover at least part of the surface of the signal line and partially coat the circuit layer, which can reduce signal loss while reducing production costs and preventing the circuit board from collapsing in the area where the signal line is located. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic cross-sectional view of a circuit substrate provided in an embodiment of the present application.

[0015] Figure 2 For Figure 1 The schematic cross-sectional view of a circuit substrate covered with an insulating layer having openings is shown.

[0016] Figure 3 for Figure 2A schematic cross-sectional view of a circuit board obtained after forming a first aerogel in the opening shown.

[0017] Figure 4 Schematic cross-sectional view of a circuit board according to some embodiments of the present application.

[0018] Figure 5 Schematic cross-sectional view of a circuit board according to some embodiments of the present application.

[0019] Figure 6 To flip Figure 3 The circuit board shown is a schematic cross-sectional view after a first through hole penetrating the substrate layer is formed in an area where a signal line is provided.

[0020] Figure 7 For Figure 6 A schematic cross-sectional view of another circuit board obtained after forming a second aerogel in the first through hole is shown.

[0021] Figure 8 A cross-sectional schematic diagram of another embodiment of the present application after a second through hole penetrating the substrate layer is formed in an area where a signal line is provided.

[0022] Fig. 9 For Figure 8 The schematic cross-sectional view shows a surface of the substrate layer facing away from the circuit layer after a mold having a groove is disposed thereon.

[0023] Fig.10 For Fig. 9 The schematic cross-sectional view of the circuit board obtained after the first aerogel is formed in the opening, the second through hole and the groove shown.

[0024] Fig.11 A cross-sectional schematic diagram of some further embodiments of the present application after a second through hole penetrating the substrate layer is formed in an area where a signal line is provided.

[0025] Fig.12 For Fig.11 A cross-sectional schematic diagram of the opening and the second through hole after the first aerogel is formed.

[0026] Fig.13 For Fig.12 The schematic cross-sectional view of the circuit board obtained after the surface of the substrate layer facing away from the circuit layer forms a third aerogel connected to the first aerogel.

[0027] Main component symbols

[0028]

[0029] DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth to facilitate a full understanding of the present application, and the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this article are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes all and any combination of one or more related listed items.

[0032] In the embodiments of the present application, for the convenience of description and not to limit the present application, the term "connection" used in the patent application specification and claims of the present application is not limited to physical or mechanical connection, whether direct or indirect. "Up", "down", "above", "below", "left", "right", etc. are only used to indicate relative position relationship. When the absolute position of the described object changes, the relative position relationship also changes accordingly.

[0033] See also Figures 1 to 3 The present invention provides a method for manufacturing a circuit board 100, which may include the following steps:

[0034] Step S11: Please refer to Figure 1 , a circuit substrate 10 is provided. The circuit substrate 10 includes a base material layer 11 and a circuit layer 13 located on a surface of the base material layer 11 . The circuit layer 13 includes a signal line 132 .

[0035] The circuit layer 13 may further include other circuits 134, such as power lines, ground lines, etc. The signal lines 132 may be located on the same surface of the substrate layer 11 as the power lines, ground lines, etc. The signal lines 132 may be used to transmit high-frequency signals.

[0036] The number of layers of the substrate layer 11 and the circuit layer 13 of the circuit substrate 10 can be one or more, wherein one circuit layer 13 is located on the outer surface of the circuit substrate 10. In this embodiment, the number of layers of the substrate layer 11 and the circuit layer 13 is taken as an example.

[0037] Step S12: Please refer to Figure 2 The surface of the substrate layer 11 provided with the circuit layer 13 is covered with an insulating layer 20 having an opening 21 , and the signal line 132 is exposed in the opening 21 .

[0038] The insulating layer 20 can be an ink layer, a coverlay (CVL), etc. In this embodiment, the insulating layer 20 is a coverlay. The insulating layer 20 includes a glue layer 23 and a coverlay 25. The coverlay 25 is located on the surface of the glue layer 23 away from the circuit substrate 10. The glue layer 23 bonds the coverlay 25 and the base layer 11.

[0039] The opening 21 penetrates the glue layer 23 and the cover layer 25 , and the signal line 132 is exposed in the opening 21 . In the extending direction of the circuit substrate 10 , the width of the opening 21 is greater than the entire width of the signal line 132 , and the entire signal line 132 is exposed in the opening 21 .

[0040] The glue layer 23 also covers and bonds the power line, ground line, etc. In some embodiments, when the insulating layer 20 is disposed on the surface of the circuit substrate 10, the glue layer 23 will also overflow toward the signal line 132 to produce overflow glue. In some embodiments, along the direction in which the circuit substrate 10 extends, the width of the overflow glue is about 0.1 mm, and the width between the edge of the opening 21 and the signal line 132 can be greater than 0.2 mm to prevent the overflow glue from contacting the signal line 132. Among them, in order to ensure the transmission performance of the signal line 132, the width between the edge of the opening 21 and the signal line 132 can also be made greater than 0.25 mm, thereby reserving more space so that the first aerogel 31 filled later can cover the signal line 132 as much as possible.

[0041] Step S13: Please refer to Figure 3 , after covering the opening 21 with the first aerogel solution and curing it, the first aerogel 31 covering the signal line 132 is formed in the opening 21 , thereby obtaining the circuit board 100 .

[0042] The first aerogel solution may be formed in the opening 21 by printing or extrusion. When the first aerogel solution is disposed in the opening 21 , the first aerogel solution also covers the signal line 132 located in the opening 21 .

[0043] The first aerogel solution may protrude relative to the insulating layer 20 to ensure that the first aerogel 31 formed after curing can completely cover the signal line 132 .

[0044] In some specific embodiments, the first aerogel solution can be formed by using methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane and other substances as silicon source substances, and adding hydrochloric acid to the silicon source substances and stirring. Adding an alkali catalyst (such as ammonia water, etc.) to the first aerogel solution, the first aerogel solution can produce a polycondensation reaction to obtain a silica gel material. Then, the silica gel material is subjected to solvent replacement (the solvent can be water, ethanol and other substances) and drying treatment (using room temperature drying, the drying temperature is 30°C-60°C, and the drying time is 4h-38h) to obtain silica aerogel, wherein the Young's modulus of the silica aerogel is 106 -10 7 N / m 2 , the tensile strength is 16 kPa, the fracture toughness is 0.8 kPa, and the compressive strength is greater than 1 MPa. In other embodiments, the first aerogel solution can use other components and other curing steps. In other embodiments, the first aerogel solution can use other components and other curing steps.

[0045] After curing, the first aerogel solution shrinks in volume relative to before curing. After coating the first aerogel solution, the surface of the first aerogel solution away from the signal line 132 may be convex, so that the first aerogel 31 formed after curing can completely cover the signal line 132. In this embodiment, the surface layer of the first aerogel 31 away from the signal line 132 is convex, and the maximum height difference ΔH between the surface of the first aerogel 31 and the insulating layer 20 is 10 μm.

[0046] The thickness of the first aerogel 31 may be 10 μm-25 μm.

[0047] In some embodiments, see Figure 4 The surface of the first aerogel 31 in the circuit board 100 - 1 facing away from the signal line 132 may be concave, and the maximum height difference ΔH between the surface of the first aerogel 31 and the insulating layer 20 is 10 μm.

[0048] In some embodiments, see Figure 5 The surface of the first aerogel 31 in the circuit board 100 - 2 facing away from the signal line 132 may be flat, and the maximum height difference ΔH between the surface of the first aerogel 31 and the insulating layer 20 is 0 μm, that is, there is no height difference.

[0049] In some embodiments, the first aerogel 31 is a hydrophobic aerogel, which can effectively isolate the circuit layer 13 from the influence of external water vapor.

[0050] In some embodiments, before coating the first aerogel solution in the opening 21 , the surface of the signal line 132 may be treated with a silane coupling agent to increase the bonding force between the signal line 132 and the first aerogel 31 formed subsequently.

[0051] Please refer again Figure 3 The circuit board 100 manufactured in this embodiment includes a circuit substrate 10, an insulating layer 20 and a first aerogel 31. The circuit substrate 10 includes a substrate layer 11 and a circuit layer 13 located on the surface of the substrate layer 11, and the circuit layer 13 includes a signal line 132. The insulating layer 20 is located on the surface of the substrate layer 11 provided with the circuit layer 13, and an opening 21 is opened on the insulating layer 20, and the signal line 132 is exposed in the opening 21. The first aerogel 31 is accommodated in the opening 21 and covers the signal line 132.

[0052] The first aerogel 31 is a solid with low density and is a material with nano-scale pores. The chemical properties of the first aerogel 31 are stable. The volume inside the first aerogel 31 can be composed of more than 99% air. The first aerogel 31 can be silicon aerogel, carbon aerogel, silicon dioxide aerogel, etc.

[0053] The first aerogel 31 with good mechanical properties is used to cover the signal line 132. For the local high-frequency transmission line layer 13 (i.e., the signal line 132), the loss of the local line can be effectively reduced, and the signal transmission performance can be improved. On the one hand, the above structure can avoid the large-scale use of materials such as polytetrafluoroethylene (PTFE) and liquid crystal polymer (LCP), which can effectively reduce the production cost; on the other hand, compared with the structure of the circuit board 100 with a cavity design, the first aerogel 31 used in this application to cover the signal line 132 can effectively prevent the circuit board 100 from collapsing in the subsequent process.

[0054] Some other embodiments of the present application provide a method for manufacturing a circuit board 100a. The manufacturing method of this embodiment can be further manufactured on the basis of the previous embodiment. Specifically, it can also include the following steps:

[0055] Step S14: Please refer to Figure 6 The circuit substrate 10 provided with the first aerogel 31 is turned over, and a first through hole 112a penetrating the base material layer 11 is formed in the area provided with the signal line 132, and the surface of the signal line 132 facing away from the first aerogel 31 and the surface of the first aerogel 31 are both exposed to the first through hole 112a.

[0056] In the extending direction of the circuit substrate 10 , the width of the first through hole 112 a is greater than the entire width of the signal line 132 , and the entire signal line 132 is exposed to the first through hole 112 a .

[0057] Step S15: Please refer to Figure 7 , the second aerogel solution is covered in the first through hole 112 a and solidified to form the second aerogel 33 a connected to the first aerogel 31 .

[0058] The first aerogel 31 and the second aerogel 33a are wrapped around the signal line 132 to further effectively reduce the transmission loss of the signal line 132. The first aerogel 31 and the second aerogel 33a together form a structure with wide ends and narrow middle, so that the first aerogel 31 and the circuit substrate 10 are closely combined.

[0059] The component of the second aerogel 33 a may be the same as or different from the component of the first aerogel 31 .

[0060] Please refer again Figure 7The circuit board 100a manufactured in this embodiment includes a circuit substrate 10, an insulating layer 20, a first aerogel 31 and a second aerogel 33a. The circuit substrate 10 includes a substrate layer 11 and a circuit layer 13 located on the surface of the substrate layer 11, and the circuit layer 13 includes a signal line 132. The insulating layer 20 is located on the surface of the substrate layer 11 provided with the circuit layer 13, and an opening 21 is provided on the insulating layer 20, and a first through hole 112a is provided on the substrate layer 11, and the signal line 132 is exposed to the opening 21 and the first through hole 112a. The first aerogel 31 is accommodated in the opening 21 and covers the signal line 132, and the second aerogel 33a is accommodated in the first through hole 112a and covers the signal line 132, and the first aerogel 31 and the second aerogel 33a are wrapped around the signal line 132 together.

[0061] See also Figure 1 , Figure 2 , Figures 8 to 10 Some other embodiments of the present application provide a method for manufacturing a circuit board 100b, which may include the following steps:

[0062] Step S21: Please refer to Figure 1 , a circuit substrate 10 is provided. The circuit substrate 10 includes a base material layer 11 and a circuit layer 13 located on a surface of the base material layer 11 . The circuit layer 13 includes a signal line 132 .

[0063] Step S22: Please refer to Figure 2 The surface of the substrate layer 11 provided with the circuit layer 13 is covered with an insulating layer 20 having an opening 21, and the signal line 132 is exposed in the opening 21. That is, step S21 and step S22 are respectively the same as step S11 and step S12.

[0064] Step S23: Please refer to Figure 8 A second through hole 114 b penetrating the base material layer 11 is formed in a region where the signal line 132 is provided.

[0065] Among them, along the extension direction of the circuit substrate 10, the width of the second through hole 114b is smaller than the overall width of the signal line 132, the second through hole 114b is located within the projection of the signal line 132 on the substrate layer 11, and the second through hole 114b is located within the projection area between the lines of the signal line 132, that is, the surface of the signal line 132 close to the substrate layer 11 is not exposed to the second through hole 114b.

[0066] Step S24: Please refer to Fig. 9 A mold 40b having a groove 41b is disposed on the surface of the substrate layer 11 away from the circuit layer 13, and the groove 41b is connected to the second through hole 114b.

[0067] The width of the second through hole 114b is smaller than the width of the groove 41b along the extension direction of the circuit substrate 10. Along the cross section perpendicular to the extension direction of the circuit substrate 10, both sides of the groove 41b protrude from the second through hole 114b, that is, the cross section formed by the groove 41b and the second through hole 114b is T-shaped.

[0068] Step S25: Please refer to Fig.10 , the opening 21 is covered with a first aerogel solution, and the first aerogel solution is also contained in the second through hole 114b and the groove 41b to form a first aerogel 31b in the second through hole 114b and the groove 41b; after the first aerogel 31b is formed, the mold 40b is removed.

[0069] The first aerogel 31 b is formed to be roughly a structure with wide ends and narrow in the middle, so that the first aerogel 31 b can be closely combined with the circuit substrate 10 .

[0070] Along the direction in which the circuit layer 13 and the substrate layer 11 are stacked, the recessed depth of the groove 41 b may be 20 μm-40 μm, which can ensure that the thickness of the first aerogel 31 b formed in the groove 41 b is 10 μm-25 μm.

[0071] Please refer again Fig.10 The circuit board 100b manufactured in this embodiment includes a circuit substrate 10, an insulating layer 20 and a first aerogel 31b. The circuit substrate 10 includes a substrate layer 11 and a circuit layer 13 located on the surface of the substrate layer 11, and the circuit layer 13 includes a signal line 132. The insulating layer 20 is located on the surface of the substrate layer 11 provided with the circuit layer 13, and an opening 21 is opened on the insulating layer 20, and the signal line 132 is exposed in the opening 21. The first aerogel 31b is accommodated in the opening 21 and covers the signal line 132. A second through hole 114b is opened in the area of ​​the substrate layer 11 corresponding to the signal line 132, and the first aerogel 31b is also accommodated in the second through hole 114b and located on the surface of the substrate layer 11 away from the signal line 132.

[0072] See also Figure 1 , Figure 2 , Figures 11 to 13 In some embodiments of the present application, a method for manufacturing a circuit board 100c is provided, which may include the following steps:

[0073] See also Figure 1 and Figure 2 Step S31 and step S32 are respectively the same as step S11 and step S12, and will not be repeated here.

[0074] Step S33: Please refer to Fig.11 A second through hole 114c penetrating through the substrate layer 11 is formed in the region where the signal line 132 is disposed. The structure of the second through hole 114c may be the same as that of the previous embodiment.

[0075] Step S34: Please refer to Fig.12 , the opening 21 is covered with the first aerogel solution, and the first aerogel solution is also contained in the second through hole 114c to form a first aerogel 31c in the second through hole 114c.

[0076] Step S35: Please refer to Fig.13 The circuit substrate 10 provided with the first aerogel 31c is turned over, and the third aerogel solution is covered and solidified in the area where the second through hole 114c is provided on the surface of the base material layer 11 away from the circuit layer 13 to form a third aerogel 35c connected to the first aerogel 31c.

[0077] The structure of the circuit board 100c formed in this embodiment is substantially the same as that of the circuit board 100b formed by the manufacturing method of steps S21-S25. The first aerogel 31c and the third aerogel 35c in this embodiment are formed in two steps. The composition of the third aerogel 35c may be the same as or different from that of the first aerogel 31c.

[0078] Please refer again Fig.13 The circuit board 100c manufactured in this embodiment includes a circuit substrate 10, an insulating layer 20, a first aerogel 31c and a third aerogel 35c. The circuit substrate 10 includes a substrate layer 11 and a circuit layer 13 located on the surface of the substrate layer 11, and the circuit layer 13 includes a signal line 132. The insulating layer 20 is located on the surface of the substrate layer 11 provided with the circuit layer 13, and an opening 21 is opened on the insulating layer 20, and the signal line 132 is exposed in the opening 21. The first aerogel 31c is accommodated in the opening 21 and covers the signal line 132. A second through hole 114c is opened in the area of ​​the substrate layer 11 corresponding to the signal line 132, and the first aerogel 31c is also accommodated in the second through hole 114c. The third aerogel 35c is located on the surface of the substrate layer 11 away from the signal line 132.

[0079] The present application uses aerogel, namely the first aerogel 31 (31b or 31c), the second aerogel 33a and / or the third aerogel 35c, to cover at least part of the surface of the signal line 132 and partially cover the circuit layer 13. While reducing signal loss, it can also reduce production costs and prevent the circuit board 100 (100a, 100b, 100c, 100-1 or 100-2) from collapsing in the area where the signal line 132 is located.

[0080] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for manufacturing a circuit board, characterized in that: The following steps are involved: Providing a circuit substrate, the circuit substrate comprising a base material layer and a circuit layer located on a surface of the base material layer, the circuit layer comprising a signal line; An insulating layer having an opening is covered on the surface of the substrate layer provided with the circuit layer, and the signal line is exposed in the opening; as well as The opening is covered with a first aerogel solution and then cured to form a first aerogel covering the signal line in the opening.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: After the step of forming the first aerogel covering the signal line, the manufacturing method further includes: Turning over the circuit substrate provided with the first aerogel, forming a first through hole penetrating the base material layer in the region provided with the signal line, wherein the surface of the signal line facing away from the first aerogel and the surface of the first aerogel are both exposed to the first through hole; and The first through hole is covered with a second aerogel solution and solidified to form a second aerogel connected to the first aerogel.

3. The method for manufacturing a circuit board according to claim 1, characterized in that: Before the step of covering the opening with the first aerogel solution, the manufacturing method further comprises: forming a second through hole penetrating the base material layer in a region where the signal line is provided; and A mold having a groove is arranged on a surface of the substrate layer away from the circuit layer, wherein the groove is connected to the second through hole; When the first aerogel solution is covered in the opening, the first aerogel solution is also contained in the second through hole and the groove, so as to form the first aerogel in the second through hole and the groove; and The mold is removed.

4. The method for manufacturing a circuit board according to claim 3, characterized in that: Along a cross section perpendicular to the extending direction of the circuit substrate, both sides of the groove protrude from the second through hole.

5. The method for manufacturing a circuit board according to claim 1, characterized in that: Before the step of covering the opening with the first aerogel solution, the manufacturing method further comprises: forming a second through hole penetrating the substrate layer in a region where the signal line is disposed; When the first aerogel solution is covered in the opening, the first aerogel solution is also contained in the second through hole to form the first aerogel in the second through hole; The circuit substrate provided with the first aerogel is turned over, and a third aerogel solution is covered and solidified in a region on a surface of the base material layer away from the circuit layer and provided with the second through hole, so as to form a third aerogel connected to the first aerogel.

6. A circuit board, characterized in that: include: A circuit substrate, comprising a base material layer and a circuit layer located on a surface of the base material layer, wherein the circuit layer comprises a signal line; An insulating layer, located on a surface of the substrate layer on which the circuit layer is disposed, the insulating layer is provided with an opening, and the signal line is exposed in the opening; as well as The first aerogel is accommodated in the opening and covers the signal line.

7. The circuit board according to claim 6, characterized in that: A first through hole is formed on the substrate layer, and the signal line is exposed in the first through hole. The circuit board further includes a second aerogel, and the second aerogel is located in the first through hole and connected to the first aerogel.

8. The circuit board according to claim 6, characterized in that: A second through hole is formed on the substrate layer, and the second through hole is located in the area where the signal line is located. The first aerogel is also accommodated in the second through hole and is also located on the surface of the substrate layer away from the circuit layer.

9. The circuit board according to claim 6, characterized in that: The substrate layer is provided with a second through hole, the second through hole is located in the area where the signal line is located, the circuit board also includes a third aerogel, the third aerogel is located in the second through hole, and the third aerogel is also located on the surface of the substrate layer away from the circuit layer.

10. The circuit board according to claim 6, characterized in that: The width between the edge of the opening and the signal line is greater than 0.2 mm.

Images