High-frequency transmission circuit board and manufacturing method thereof

Abstract

The invention provides a high-frequency transmission circuit board and a manufacturing method thereof, and the method comprises the steps: providing a first circuit substrate which comprises a first aerogel layer, and a first dielectric layer, a first circuit layer, a second dielectric layer and a second circuit layer which are sequentially stacked in the thickness direction, the first dielectric layer is provided with a first slot in a penetrating manner, and the second dielectric layer is provided with a second slot in a penetrating manner; the first aerogel layer is arranged in the first slot; a second circuit substrate is provided, the second circuit substrate comprises a second aerogel layer, a third dielectric layer and a third circuit layer, the third dielectric layer and the third circuit layer are stacked, a second groove is formed in the third dielectric layer in a penetrating mode, and the second aerogel layer is arranged in the second groove; laminating the first circuit substrate and the second circuit substrate; during stacking, the first aerogel layer and the second aerogel layer face each other and are correspondingly arranged; after pressing, the first aerogel layer and the second aerogel layer are overlapped to form an aerogel body; a bending area and a non-bending area except the bending area are defined in the high-frequency transmission circuit board, and the aerogel is arranged in the bending area.

Description

Technical Field

[0001] The invention relates to a high-frequency transmission circuit board and a manufacturing method thereof. Background Art

[0002] In order to cater to the development trend of high frequency, high speed and functionalization, the structural design of high-frequency transmission circuit boards mainly adopts the following two schemes: (1) Design a cavity structure in the circuit board and use air as the transmission medium. Since air has an extremely low dielectric constant (Dk is approximately 1) and dielectric loss (Df is close to 0), it can achieve extremely low dielectric transmission loss. However, when the cavity structure is bent, the distance between the circuit layers on both sides changes, and the capacitance also changes accordingly, which will cause the characteristic impedance to change, and then cause the impedance mismatch problem. In addition, the cavity structure cannot be used in areas that need to be bent repeatedly. (2) Dielectric materials with low dielectric constant and low dielectric loss, such as modified polyimide (Dk is about 3.2, Df is about 0.005), liquid crystal polymer (Dk is about 2.8, Df is about 0.002) and polytetrafluoroethylene (Dk is about 2.5, Df is about 0.001) are used as transmission media to reduce dielectric transmission loss. However, compared with air, the dielectric constant and dielectric loss of this type of dielectric material are still relatively high, and the cost is relatively high. Summary of the invention

[0003] In view of this, it is necessary to provide a high-frequency transmission circuit board and a manufacturing method thereof that can solve the above-mentioned technical problems.

[0004] The present invention provides a method for manufacturing a high-frequency transmission circuit board, comprising the steps of:

[0005] Providing a first circuit substrate, the first circuit substrate comprising a first aerogel layer and a first dielectric layer, a first circuit layer, a second dielectric layer and a second circuit layer sequentially stacked in a thickness direction, the first dielectric layer being penetrated by a first slot to expose a portion of the first circuit layer, and the first aerogel layer being disposed in the first slot;

[0006] Providing a second circuit substrate, the second circuit substrate comprising a second aerogel layer and a stacked third dielectric layer and a third circuit layer, the third dielectric layer being penetrated by a second slot to expose a portion of the third circuit layer, and the second aerogel layer being arranged in the second slot;

[0007] The first circuit substrate and the second circuit substrate are stacked and pressed together; during stacking, the first aerogel layer and the second aerogel layer are arranged facing each other and correspondingly; after pressing together, the first aerogel layer and the second aerogel layer overlap to form an aerogel body;

[0008] Wherein, a bending area and a non-bending area other than the bending area are defined in the high-frequency transmission circuit board along a direction perpendicular to the thickness direction, and the aerogel body is correspondingly arranged in the bending area.

[0009] The present invention also provides a high-frequency transmission circuit board, the high-frequency transmission circuit board comprising an aerogel body and a second circuit layer, a second dielectric layer, a first circuit layer, a first dielectric layer, a third dielectric layer and a third circuit layer sequentially stacked in a thickness direction, the aerogel body being arranged between the third circuit layer and the first circuit layer, and the first dielectric layer and the third dielectric layer covering the aerogel body;

[0010] Wherein, a bending area and a non-bending area other than the bending area are defined in the high-frequency transmission circuit board along a direction perpendicular to the thickness direction, and the aerogel body is correspondingly arranged in the bending area.

[0011] In the manufacturing method of the high-frequency transmission circuit board provided by the present invention, by arranging an aerogel body in the bending area, the impedance mismatch problem caused by the air structure can be solved, and the air dielectric properties are retained while having high mechanical strength, so that the high-frequency transmission circuit board has low manufacturing cost, low dielectric constant and low dielectric loss, and can be bent repeatedly. In addition, by arranging a first aerogel layer on the first circuit substrate and a second aerogel layer on the second circuit substrate, the two are stacked and pressed to obtain the aerogel body, so that the aerogel body can fully fill the cavity and solve the problem of glue overflowing in the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. 4 is a schematic cross-sectional view of a first single-sided board provided in one embodiment of the present invention.

[0013] Figure 2 It is Figure 1 The cross-sectional schematic diagram is shown after a second single-sided board is laminated and built up on the first single-sided board.

[0014] Figure 3 It is Figure 2 The cross-sectional schematic diagram shown is after a photosensitive dry film is disposed on the surface of the second circuit layer.

[0015] Figure 4 Yes Figure 3 The cross-sectional schematic diagram of the photosensitive dry film after being exposed and developed to form a first opening is shown.

[0016] Figure 5 Yes Figure 4 The cross-sectional view is shown after the second circuit layer is etched to form a third groove and the photosensitive pattern is removed.

[0017] Figure 6 It is Figure 5The cross-sectional view is shown after the second circuit layer, the first dielectric layer and the first adhesive layer are penetrated to form a first blind hole and the first dielectric layer is penetrated to form a first groove.

[0018] Figure 7 It is Figure 6 The cross-sectional schematic diagram shown is after the first conductive hole is formed by electroplating in the blind hole.

[0019] Figure 8 It is Figure 7 The cross-sectional schematic diagram shown is after the first film layer is disposed on the surface of the second circuit layer.

[0020] Fig. 9 It is Figure 8 The cross-sectional schematic diagram shown is after a second film layer is disposed on the surface of a first film layer to form a first covering film.

[0021] Fig.10 It is Fig. 9 The cross-sectional schematic diagram of the first circuit substrate obtained by arranging the first aerogel layer in the first groove is shown.

[0022] Fig.11 FIG. 4 is a schematic cross-sectional view of a third single-sided board provided in one embodiment of the present invention.

[0023] Fig.12 It is Fig.11 The cross-sectional diagram shown is a diagram of a third dielectric layer after a second groove is formed through the third dielectric layer.

[0024] Fig.13 It is Fig.12 The cross-sectional schematic diagram of the second circuit substrate obtained after the second aerogel layer is arranged in the second groove is shown.

[0025] Fig.14 Yes Fig.10 The first circuit substrate and Fig.13 The cross-sectional schematic diagram of the second circuit substrate after lamination and pressing is shown.

[0026] Fig.15 It is Fig.14 The third circuit layer, the third dielectric layer, the second glue layer, and the second dielectric layer are shown as a cross-sectional schematic diagram after the second blind hole is formed through the third circuit layer, the third dielectric layer, the second glue layer, and the second dielectric layer.

[0027] Fig.16 It is Fig.15 The cross-sectional schematic diagram shown is after the second conductive hole is formed by electroplating in the second blind hole.

[0028] Fig.17 It is Fig.16 The cross-sectional schematic diagram shown is after the third film layer is disposed on the surface of the third circuit layer.

[0029] Fig.18 It is Fig.17 The cross-sectional schematic diagram of the high-frequency transmission circuit board obtained after the fourth film layer is arranged on the surface of the third film layer is shown.

[0030] Main component symbols

[0031] High frequency transmission circuit board 100 First circuit substrate 1

[0032] The first single-sided board 10 The third single-sided board 30

[0033] The first dielectric layer 101 and the third dielectric layer 301

[0034] First circuit layer 102 Third circuit layer 302

[0035] First slot 104 Second slot 31

[0036] First glue layer 11 Second aerogel layer 32

[0037] Second single-sided board 12 Second circuit substrate 2

[0038] Second medium layer 121 Aerogel body 40

[0039] Second circuit layer 122 Second glue layer 42

[0040] The third slot 124 The second blind hole 50

[0041] Photosensitive dry film 20 Second conductive hole 52

[0042] Photosensitive pattern 21 Second covering film 60

[0043] Opening 212 Third film layer 61

[0044] First blind hole 22 Fourth film layer 62

[0045] First conductive via 24 Second opening 63

[0046] First covering film 26 bending area A

[0047] First film layer 261 non-bending area B

[0048] The second film layer 262 has a thickness direction L

[0049] The first opening 263 contains the cavity R

[0050] First aerogel layer 28

[0051] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] See also Figures 1 to 18 According to one embodiment of the present invention, a method for manufacturing a high-frequency transmission circuit board 100 is provided, comprising the following steps:

[0054] Step S1, see Fig.10 A first circuit substrate 1 is provided, wherein the first circuit substrate 1 comprises a first aerogel layer 28, a first conductive hole 24, and a first dielectric layer 101, a first circuit layer 102, a second dielectric layer 121, and a second circuit layer 122 sequentially stacked along a thickness direction L, wherein the first dielectric layer 101 is penetrated by a first slot 104, a portion of the first circuit layer 102 is exposed by the first slot 104, the first aerogel layer 28 is disposed in the first slot 104 and connected to the first circuit layer 102. The first conductive hole 24 penetrates the second dielectric layer 121 and electrically connects the first circuit layer 102 and the second circuit layer 122.

[0055] The surface of the first aerogel layer 28 facing away from the first circuit layer 102 protrudes beyond the surface of the first dielectric layer 101 facing away from the first circuit layer 102 .

[0056] In some embodiments, the first circuit substrate 1 further includes a first covering film 26, and the first covering film 26 covers the second circuit layer 122. Along the thickness direction L, the first covering film 26 and the corresponding second circuit layer 122 are penetrated by a third slot 124, and the third slot 124 is arranged along the thickness direction L corresponding to the first slot 104. In this embodiment, the width of the first slot 104 is substantially equal to the width of the third slot 124.

[0057] In some embodiments, a surface of the first covering film 26 facing away from the second circuit layer 122 is provided with a plurality of first openings 263 that are spaced apart and do not penetrate the first covering film 26 , so that the thickness of the region provided with the first openings 263 is smaller than the thickness of the region without the first openings 263 .

[0058] In some embodiments, the first circuit substrate 1 further includes a first adhesive layer 11 , and the first adhesive layer 11 is disposed between the first circuit layer 102 and the second dielectric layer 121 to firmly bond the first circuit layer 102 and the second dielectric layer 121 .

[0059] Specifically, the method for manufacturing the first circuit substrate 1 may include the following steps:

[0060] Step S11, see Figure 1 , providing a first single-sided board 10, wherein the first single-sided board 10 includes a first dielectric layer 101 and a first circuit layer 102 stacked along the thickness direction L.

[0061] Step S12, see Figure 2 A second single-sided board 12 is laminated on the surface of the first single-sided board 10 along the thickness direction L, wherein the second single-sided board 12 includes a stacked second dielectric layer 121 and a second circuit layer 122 , and the second dielectric layer 121 is bonded to the first circuit layer 102 through a first adhesive layer 11 .

[0062] Step S13, see Figure 3 , Figure 4 and Figure 5 A photosensitive dry film 20 is disposed on the surface of the second circuit layer 122 away from the second dielectric layer 121, and the photosensitive dry film 20 is exposed and developed to form a photosensitive pattern 21. The photosensitive pattern 21 is penetrated by an opening 212, and the second circuit layer 122 is etched corresponding to the opening 212 to form the third groove 124, and finally the photosensitive pattern 21 is removed.

[0063] In some embodiments, before step S13, the method further includes: cleaning the plate surface using plasma technology.

[0064] Step S14, see Figure 6 A first slot 104 is formed through the first dielectric layer 101 , and a portion of the first circuit layer 102 is exposed through the first slot 104 . The first slot 104 and the third slot 124 are correspondingly disposed along the thickness direction L.

[0065] The step S14 further includes: opening a first blind hole 22 through the second circuit layer 122 , the second dielectric layer 121 and the first adhesive layer 11 , and a portion of the first circuit layer 102 is exposed through the first blind hole 22 .

[0066] Specifically, the first blind hole 22 and the first slot 104 may be formed by, but not limited to, laser drilling technology.

[0067] Step S15, see Figure 7, a first conductive via 24 is formed by electroplating in the first blind hole 22 , and the first conductive via 24 electrically connects the second circuit layer 122 and the first circuit layer 102 .

[0068] Step S16, see Fig. 9 , a first covering film 26 is disposed on the surface of the second circuit layer 122 .

[0069] Specifically, step S16 includes:

[0070] See also Figure 8 , a first film layer 261 is attached to the surface of the second circuit layer 122 .

[0071] See also Fig. 9 A second film layer 262 is attached to the surface of the first film layer 261 away from the second circuit layer 122 . The second film layer 262 is pre-cut and penetrated to form a first opening 263 . The first film layer 261 and the second film layer 262 overlap to form the first covering film 26 .

[0072] Step S17, see Fig.10 , a first aerogel layer 28 is disposed in the first groove 104 to obtain a first circuit substrate 1.

[0073] Specifically, the first aerogel layer 28 is made of polyimide resin, which can be formed by printing and filling the first slot 104 with polyimide colloid, and then removing the solvent by, but not limited to, baking or supercritical fluid displacement method.

[0074] In some embodiments, the method for preparing the polyimide colloid may include: first dissolving a diamine monomer in a solvent, then adding a di-anhydride monomer, and mechanically stirring for 3 to 6 hours under a nitrogen atmosphere and room temperature to synthesize a polyimide precursor (precursor) - polyamic acid, then adding a catalyst and a dehydrating agent and heating to 120°C to 150°C, and mechanically stirring for 1 to 3 hours to obtain a polyimide colloid.

[0075] Step S2, see Fig.13 A second circuit substrate 2 is provided, wherein the second circuit substrate 2 includes a second aerogel layer 32 and a stacked third dielectric layer 301 and a third circuit layer 302, wherein the third dielectric layer 301 is penetrated by a second slot 31 to expose a portion of the third circuit layer 302, and the second aerogel layer 32 is disposed in the second slot 31 and connected to the third circuit layer 302.

[0076] In this embodiment, the materials of the first dielectric layer 101, the second dielectric layer 121 and the third dielectric layer 301 are all dielectric materials with low dielectric constant and low dielectric loss (Dk=2.7-3.2; Df=0.002-0.003), specifically modified polyimide (MPI), liquid crystal polymer (LCP) and polytetrafluoroethylene (PTFE). The thickness of the first circuit layer 102, the second circuit layer 122 and the third circuit layer 302 is approximately 12μm-30μm respectively, and the thickness of the first dielectric layer 101, the second dielectric layer 121 and the third dielectric layer 301 is greater than the thickness of the first circuit layer 102, the second circuit layer 122 and the third circuit layer 302.

[0077] Specifically, the method for manufacturing the second circuit substrate 2 may include the following steps:

[0078] See also Fig.11 , providing a third single-sided board 30 , wherein the third single-sided board 30 includes a stacked third dielectric layer 301 and a third circuit layer 302 .

[0079] See also Fig.12 A second slot 31 is formed through the third dielectric layer 301 to expose a portion of the third circuit layer 302 .

[0080] Specifically, the second slot 31 may be formed by, but is not limited to, laser cutting.

[0081] See also Fig.13 , a second aerogel layer 32 is disposed in the second groove 31 .

[0082] The surface of the second aerogel layer 32 facing away from the third circuit layer 302 protrudes beyond the surface of the third dielectric layer 301 facing away from the third circuit layer 302 .

[0083] In this embodiment, the material and manufacturing method of the second aerogel layer 32 are substantially the same as those of the first aerogel layer 28. The dielectric constant (Dk) of the first aerogel layer 28 and the second aerogel layer 32 is less than 1.4, the dielectric loss (Df) is less than 0.002 (@10GHz), and the first aerogel layer 28 and the second aerogel layer 32 both have irregular pore structures, with an average pore size of less than 2nm and a porosity greater than 95%.

[0084] Step S3, see Fig.14, along the thickness direction L, the first circuit substrate 1 and the second circuit substrate 2 are stacked and pressed together through a second adhesive layer 42. During stacking, the first aerogel layer 28 and the second aerogel layer 32 are arranged facing each other and correspondingly; after pressing, the first aerogel layer 28 and the second aerogel layer 32 overlap to form an aerogel body 40, and the first groove 104 and the second groove 31 are connected to form a receiving cavity R, and the aerogel body 40 is filled in the receiving cavity R.

[0085] Wherein, the thickness of the aerogel body 40 is 130 μm to 230 μm.

[0086] By providing the first aerogel layer 28 and the second aerogel layer 32, the two are pressed together to form the aerogel body 40, so that the aerogel body 40 can completely fill the receiving cavity R. In addition, the aerogel body 40 has an irregular pore structure with an average pore diameter of less than 2nm, which belongs to an ultra-microporous material, so the pore resistance is large, which can effectively prevent liquid and colloid penetration. Therefore, during the pressing process, the aerogel body 40 can effectively solve the problem of glue overflow.

[0087] Step S4, see Fig.15 and Fig.16 , along the thickness direction L, a second blind hole 50 is opened through the third circuit layer 302, the third dielectric layer 301, the second glue layer 42 and the first dielectric layer 101, and a second conductive hole 52 is formed by electroplating in the second blind hole 50, and the second conductive hole 52 electrically connects the third circuit layer 302 and the first circuit layer 102.

[0088] The second conductive hole 52 is arranged away from the aerogel body 40 .

[0089] Step S5, see Fig.17 and Fig.18 A second covering film 60 is disposed on the surface of the third circuit layer 302 , and a plurality of second openings 63 which are spaced apart and do not penetrate the second covering film 60 are concavely disposed on the surface of the second covering film 60 away from the third circuit layer 302 , thereby obtaining the high-frequency transmission circuit board 100 .

[0090] A bending area A and a non-bending area B other than the bending area A are defined in the high-frequency transmission circuit board 100 , and the aerogel body 40 is disposed corresponding to the bending area A.

[0091] In this embodiment, the bending area A is located at the center of the high-frequency transmission circuit board 100, and the non-bending area B is provided on opposite sides of the bending area A. The second opening 63 can be provided in the bending area A or in the non-bending area B, so that the thickness of the area provided with the second opening 63 is less than the thickness of the area without the second opening 63, and the interval between each two second openings 63 is 5 mm to 10 mm. Since the bending strength is inversely proportional to the material thickness, the second opening 63 is provided to reduce the thickness, so that the tensile strength during bending can be improved and the bending rate can be increased.

[0092] Specifically, step S5 may include:

[0093] First, a third film layer 61 is disposed on the surface of the third circuit layer 302, and then a fourth film layer 62 is attached to the surface of the third film layer 61 to form the second covering film 60. The fourth film layer 62 is pre-cut and penetrated to form a second opening 63.

[0094] In addition, compared with the brittle and easily broken properties of silica aerogel, the aerogel body 40 is made of polyimide, which has the properties of bendability, high temperature resistance, high mechanical strength, etc., and its dielectric constant is about 1.3 and dielectric loss is about 0.001. By arranging the aerogel body 40 in the bending area A, the porosity of the aerogel body 40 is greater than 95%, so that the bending area A has high mechanical strength while retaining the air dielectric properties, so that the high-frequency transmission circuit board 100 has low cost and low dielectric constant and low dielectric loss, which can increase the transmission speed, reduce the transmission loss, and can be bent repeatedly.

[0095] In addition, by providing a second opening 63 in the second covering film 60, the high-frequency transmission circuit board 100 has a height difference in the thickness direction L, which can improve the bending strength and reduce the failure problems such as rebound and breakage of the bending area A when bending.

[0096] See also Fig.18In one embodiment of the present invention, a high-frequency transmission circuit board 100 having a thickness direction L is provided. The high-frequency transmission circuit board 100 includes an aerogel body 40, a first conductive hole 24, a second conductive hole 52, and a second circuit layer 122, a second dielectric layer 121, a first circuit layer 102, a first dielectric layer 101, a third dielectric layer 301, and a third circuit layer 302 stacked in sequence along the thickness direction L. The first dielectric layer 101 and the third dielectric layer 301 are penetrated by a receiving cavity R, the aerogel body 40 is disposed in the receiving cavity R, and opposite sides of the aerogel body 40 are respectively connected to the third circuit layer 302 and the first circuit layer 102. The first conductive hole 24 is at least penetrated by the second dielectric layer 121 and electrically connects the first circuit layer 102 and the second circuit layer 122. The second conductive hole 52 is at least penetrated by the first dielectric layer 101 and the third dielectric layer 301 and electrically connects the third circuit layer 302 and the first circuit layer 102.

[0097] Along the thickness direction L, the high frequency transmission circuit board 100 is defined with a bending area A and a non-bending area B except the bending area A. The aerogel body 40 is correspondingly disposed in the bending area A. The first conductive hole 24 and the second conductive hole 52 are disposed in the non-bending area B.

[0098] The aerogel body 40 is made of polyimide resin, with a dielectric constant (Dk) less than 1.4 and a dielectric loss (Df) less than 0.002 (@10GHz), and has an irregular pore structure, an average pore size less than 2nm, and a porosity greater than 95%. The first dielectric layer 101, the second dielectric layer 121, and the third dielectric layer 301 are all made of dielectric materials with low dielectric constants and low dielectric losses, specifically modified polyimide (MPI), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), etc.

[0099] In some embodiments, the high-frequency transmission circuit board 100 further includes a first cover film 26 and a second cover film 60, wherein the first cover film 26 covers the surface of the second circuit layer 122, and the second cover film 60 covers the surface of the third circuit layer 302. Corresponding to the bending area A, the first cover film 26 and the second circuit layer 122 are penetrated with a third slot 124, so that the thickness of the bending area A is less than the thickness of the non-bending area B. In some embodiments, the surface of the first cover film 26 away from the second circuit layer 122 is concavely provided with a plurality of first openings 263 that are spaced apart and do not penetrate the first cover film 26, and the surface of the second cover film 60 away from the third circuit layer 302 is concavely provided with a plurality of second openings 63 that are spaced apart and do not penetrate the second cover film 60, and the second openings 63 are provided in the bending area A and the non-bending area B, so that the thickness of the area where the second openings 63 are provided is less than the thickness of the area where the second openings 63 are not provided.

[0100] In some implementations, a first adhesive layer 11 is further disposed between the second dielectric layer 121 and the first circuit layer 102 , and a second adhesive layer 42 is further disposed between the first dielectric layer 101 and the third dielectric layer 301 .

[0101] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the present invention. Therefore, equivalent changes made according to the present invention still fall within the scope of the present invention.

Claims

1. A method for manufacturing a high-frequency transmission circuit board, characterized in that: Includes steps: Providing a first circuit substrate, the first circuit substrate comprising a first aerogel layer and a first dielectric layer, a first circuit layer, a second dielectric layer and a second circuit layer sequentially stacked in a thickness direction, the first dielectric layer being penetrated by a first slot to expose a portion of the first circuit layer, and the first aerogel layer being disposed in the first slot; Providing a second circuit substrate, the second circuit substrate comprising a second aerogel layer and a stacked third dielectric layer and a third circuit layer, the third dielectric layer being penetrated by a second slot to expose a portion of the third circuit layer, and the second aerogel layer being arranged in the second slot; The first circuit substrate and the second circuit substrate are stacked and pressed together; during stacking, the first aerogel layer and the second aerogel layer are arranged facing each other and correspondingly; after pressing together, the first aerogel layer and the second aerogel layer overlap to form an aerogel body; Wherein, a bending area and a non-bending area other than the bending area are defined in the high-frequency transmission circuit board along a direction perpendicular to the thickness direction, and the aerogel body is correspondingly arranged in the bending area.

2. The method for manufacturing a high-frequency transmission circuit board according to claim 1, characterized in that: The porosity of the aerogel body is greater than 95%, and the average pore size is less than 2nm; the dielectric constant of the aerogel body is less than 1.4, and the dielectric loss is less than 0.

002.

3. The method for manufacturing a high-frequency transmission circuit board according to claim 1, characterized in that: The method for manufacturing the first circuit substrate comprises the steps of: Providing a first single-sided board, wherein the first single-sided board comprises a stacked first dielectric layer and a first circuit layer; Laminating a second single-sided board on the surface of the first single-sided board along the thickness direction, wherein the second single-sided board includes a stacked second dielectric layer and a second circuit layer, and the second dielectric layer faces the first circuit layer; A first slot is formed through the first dielectric layer, and a third slot is formed through the second circuit layer, wherein the first slot is arranged corresponding to the first slot along the thickness direction; A first covering film is attached to the surface of the second circuit layer, and a surface of the first covering film facing away from the second circuit layer is concavely provided with a plurality of first openings which are arranged at intervals and do not penetrate the first covering film, so that the thickness of the area provided with the first openings is smaller than the thickness of the area without the first openings; The first aerogel layer is disposed in the first groove to obtain the first circuit substrate.

4. The method for manufacturing a high-frequency transmission circuit board according to claim 3, characterized in that: The step of "arranging the first aerogel layer in the first groove" includes: The first slot is filled with polyimide colloid by printing, and the first aerogel layer is obtained after the solvent in the polyimide colloid is removed. The surface of the first aerogel layer facing away from the first circuit layer protrudes from the surface of the first dielectric layer facing away from the first circuit layer.

5. The method for manufacturing a high-frequency transmission circuit board according to claim 1, characterized in that: After the step of "stacking and pressing the first circuit substrate and the second circuit substrate", the method further includes: A second covering film is arranged on the surface of the third circuit layer, and a plurality of second openings which are arranged at intervals and do not penetrate the second covering film are recessed in the surface of the second covering film which is away from the third circuit layer, and the second openings are arranged at least in the bending zone, so that the thickness of the area in the bending zone corresponding to the second openings is smaller than the thickness of the area without the second openings.

6. The method for manufacturing a high-frequency transmission circuit board according to claim 1, characterized in that: The material of the first dielectric layer, the second dielectric layer and the third dielectric layer is at least one of modified polyimide, liquid crystal polymer or polytetrafluoroethylene.

7. A high-frequency transmission circuit board, characterized in that: The high-frequency transmission circuit board comprises an aerogel body and a second circuit layer, a second dielectric layer, a first circuit layer, a first dielectric layer, a third dielectric layer and a third circuit layer stacked in sequence along the thickness direction, the aerogel body is arranged between the third circuit layer and the first circuit layer, and the first dielectric layer and the third dielectric layer cover the aerogel body; Wherein, a bending area and a non-bending area other than the bending area are defined in the high-frequency transmission circuit board along a direction perpendicular to the thickness direction, and the aerogel body is correspondingly arranged in the bending area.

8. The high-frequency transmission circuit board according to claim 7, characterized in that: The porosity of the aerogel is greater than 95%, and the average pore size is less than 2 nm; The dielectric constant of the aerogel body is less than 1.4, and the dielectric loss is less than 0.

002.

9. The high-frequency transmission circuit board according to claim 7, characterized in that: The material of the first dielectric layer, the second dielectric layer and the third dielectric layer is at least one of modified polyimide, liquid crystal polymer or polytetrafluoroethylene.

10. The high-frequency transmission circuit board according to claim 7, characterized in that: The high-frequency transmission circuit board also includes a first covering film and a second covering film, the first covering film covers the surface of the second circuit layer, and the second covering film covers the surface of the third circuit layer; corresponding to the bending area, the first covering film and the second circuit layer are penetrated by a third groove, and the surface of the first covering film away from the second circuit layer is concavely provided with a plurality of first openings that are arranged at intervals and do not penetrate the first covering film, so that the thickness of the area provided at the first opening is less than the thickness of the area not provided at the first opening; the surface of the second covering film away from the third circuit layer is concavely provided with a plurality of second openings that are arranged at intervals and do not penetrate the second covering film, and the second opening is at least provided in the bending area, so that the thickness of the area in the bending area corresponding to the second opening is less than the thickness of the area without the second opening.

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