PTFE-based high-dielectric-constant high-frequency copper-clad plate and production process thereof

Abstract

The PTFE-based high-dielectric-constant high-frequency copper-clad plate comprises a copper foil layer, a dielectric layer and a copper foil layer which are stacked in sequence, the dielectric layer is composed of an impregnated fabric layer and a base film layer which are alternately stacked, the base film layer and the copper foil layer are connected in a composite mode, the impregnated fabric layer and the base film layer both comprise polytetrafluoroethylene resin, the thickness of the dielectric layer is Tmm, and the thickness of the copper foil layer is Tmm. The integer part of T / 0.127 is N; the number of the base film layers is one of N-2, N-1 and N. The copper-clad plate provided by the invention is a PTFE-based copper-clad plate and is suitable for a reflow soldering process; the preferable number of base film layers is beneficial to improving the dielectric constant of the copper-clad plate and reducing the dielectric loss of the copper-clad plate. The invention further discloses a production process of the PTFE-based high-dielectric-constant high-frequency copper-clad plate. The base film is prepared through blank preparation, extrusion and rolling, and the copper-clad plate prepared from the base film is uniform in thickness. And the copper-clad plate with uniform thickness is more tightly attached to other components, so that the operation stability of the high-frequency circuit board is improved.

Description

Technical Field

[0001] This invention relates to the field of copper clad laminate technology, specifically to a PTFE-based high dielectric constant high frequency copper clad laminate and its manufacturing process. Background Technology

[0002] With the rapid development of fifth-generation (5G) and future generations of mobile communication technologies, automotive radar, satellite communication, satellite navigation and other high-frequency applications, people have increasingly higher requirements for the performance of high-frequency circuit board materials.

[0003] Currently, the high dielectric constant copper clad laminates available on the market are mainly supplied by foreign manufacturers, with representative products including AD1000, RO3010, RT / duroid6010, and TMM10. However, the dielectric constant of these products is around 10.0, which is insufficient to meet the application requirements of further miniaturization and weight reduction in 5G, 6G, and navigation antennas.

[0004] High-frequency copper-clad laminates prepared using polyphenylene oxide (PPE) systems can increase the dielectric constant of copper-clad laminates to 16 (or even above 20), but these copper-clad laminates have high dielectric loss and are not resistant to high temperatures (and cannot be matched with reflow soldering processes).

[0005] Therefore, there is an urgent need in the field for a new type of high dielectric constant copper clad laminate that has high dielectric constant and low dielectric loss while being compatible with reflow soldering processes. Summary of the Invention

[0006] One of the objectives of this invention is to overcome the deficiencies in the prior art and provide a PTFE-based high dielectric constant high-frequency copper-clad laminate with high dielectric constant and low dielectric loss.

[0007] To solve the above technical problems, the present invention provides a PTFE-based high dielectric constant high frequency copper clad laminate, comprising a copper foil layer, a dielectric layer and a copper foil layer stacked sequentially, wherein the dielectric layer is an alternating layer of impregnated cloth and a base film layer, the base film layer and the copper foil layer are compositely connected, and the components of the impregnated cloth layer and the base film layer both include polytetrafluoroethylene resin, the thickness of the dielectric layer is T mm, and the integer part of T / 0.127 is N; The number of layers in the base film is one of N-2, N-1, and N.

[0008] Furthermore, N is not less than 4. Even further, the number of layers in the base film is N.

[0009] A preferred technical solution is that, by mass parts, the base film layer comprises 60-72 parts of ceramic particles and 28-40 parts of polytetrafluoroethylene resin; further, the number of parts of the ceramic particles can be selected as 60, 62, 64, 66, 68, 70, 72 points or a range of the above two points as the maximum and minimum values; the number of parts of the polytetrafluoroethylene resin can be selected as 28, 30, 32, 34, 36, 38, 40 points or a range of the above two points as the maximum and minimum values.

[0010] A preferred technical solution is that the ceramic particles comprise titanium dioxide and calcium strontium titanate, wherein the mass ratio of titanium dioxide to calcium strontium titanate is 1:(1.5~2.6). Further, the mass ratio of titanium dioxide to calcium strontium titanate can be selected as a point value of 1:1.5, 1:1.7, 1:1.9, 1:2, 1:2.1, 1:2.3, or 1:2.6, or a range of two of the above point values ​​as the maximum and minimum values.

[0011] Furthermore, the ceramic particles are a combination of titanium dioxide and calcium strontium titanate.

[0012] A preferred technical solution is that the ceramic particles are angular or spherical in shape, and the average particle size of the ceramic particles is 5~15μm.

[0013] Furthermore, the average particle size of the ceramic particles can be selected as a point value of 5, 7, 9, 10, 12, 13, or 15 μm, or as an interval value of the above two point values ​​as the maximum and minimum values.

[0014] A preferred technical solution is that the Sr / (Sr+Ca) ratio in the calcium strontium titanate is 0.4~0.55 in molar ratio.

[0015] Furthermore, the Sr / (Sr+Ca) ratio in the strontium calcium titanate can be selected as a molar ratio of 0.4, 0.45, 0.5, 0.5, or 0.55, or two of the above points as an interval value for the maximum and minimum values.

[0016] The second objective of this invention is to provide a manufacturing process for PTFE-based high-dielectric-constant high-frequency copper-clad laminates, comprising the following steps: S10: Mix polytetrafluoroethylene resin and ceramic particles, mature, form blanks, extrude into sheets, calender, and bake to obtain a base film; Fiberglass cloth is impregnated with polytetrafluoroethylene emulsion and then baked to obtain impregnated cloth. S20: Steel plate, copper pad, copper foil, alternating layers of impregnated cloth and base film, copper foil, copper pad, and steel plate are stacked in sequence, and the copper foil is bonded to the base film. S30: PTFE-based high dielectric constant high-frequency copper-clad laminate obtained by hot pressing and sintering; Furthermore, the hot pressing sintering temperature is 370~390℃, the holding time is 30~150min, and the pressure is 3~6MPa.

[0017] Furthermore, the hot pressing sintering temperature can be selected from points of 370, 375, 380, 385, and 390°C, or a range of two of the above points as the maximum and minimum values. The holding time can be selected from points of 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150 min, or a range of two of the above points as the maximum and minimum values. The pressure can be selected from points of 3, 4, 5, and 6 MPa, or a range of two of the above points as the maximum and minimum values.

[0018] A preferred technical solution is that the thickness of the glass fiber cloth is 10~35μm. Further, the thickness of the glass fiber cloth is 10~14μm.

[0019] Furthermore, the thickness of the fiberglass cloth can be selected as a value of 10, 11, 12, 13, or 14 points, or as a range of the above two values ​​as the maximum and minimum values.

[0020] A preferred technical solution is that the thickness of the glass fiber cloth is T. 玻纤布 μm, the thickness of the impregnated cloth is (T 玻纤布 +8)~(T 玻纤布 +16) μm.

[0021] Furthermore, the thickness of the impregnated cloth can be selected as T. 玻纤布 +8, T 玻纤布 +10, T 玻纤布 +12, T 玻纤布 +14, T 玻纤布 +16 points or the two points mentioned above are used as the range of maximum and minimum values.

[0022] The preferred technical solution is that, in S00, the pressure of the preformation step is 4~8MPa.

[0023] Furthermore, the pressure in the blanking step can be selected as a point value of 4, 5, 6, 7, or 8 MPa, or a range of the above two point values ​​as the maximum and minimum values.

[0024] The preferred technical solution is that, in S00, the pressure of the extrusion step is 4~12MPa and the speed is 0.5~5mm / min.

[0025] Furthermore, the pressure of the extrusion step can be selected as 4, 5, 6, 7, 8, 9, 10, 11, 12 MPa points or a range of the above two points as the maximum and minimum values; the speed can be selected as 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm / min points or a range of the above two points as the maximum and minimum values.

[0026] The advantages and beneficial effects of this invention are as follows: The PTFE-based high dielectric constant high-frequency copper-clad laminate of this invention has a reasonable structure, high dielectric constant, and low dielectric loss. The copper-clad laminate of this invention is a PTFE-based copper-clad laminate, suitable for reflow soldering processes; The optimal number of base film layers is beneficial for increasing the dielectric constant of copper clad laminate and reducing its dielectric loss. This invention produces a base film through blanking, extrusion, and calendering, resulting in copper-clad laminates with uniform thickness. The uniform thickness of the copper-clad laminate allows for tighter bonding with other components, improving the operational stability of high-frequency circuit boards. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0028] raw material: Fiberglass cloth: Type 1017 (average thickness 12μm), Type 1035 (average thickness 27μm), Type 106 (average thickness 32μm); Titanium dioxide: average particle size 10 μm.

[0029] 1. Examples and Comparative Examples Example 1

[0030] The preparation process of the impregnated cloth in Example 1 includes the following steps: 1017 type glass fiber cloth is impregnated with 60% polytetrafluoroethylene emulsion, and the thickness of the impregnated cloth is measured to be 20 μm after baking.

[0031] The manufacturing process of the PTFE-based high-dielectric-constant high-frequency copper-clad laminate in Example 1 includes the following steps: S1: By mass, 31 parts of polytetrafluoroethylene powder, 23 parts of modified titanium dioxide particles (modified by perfluorosilane coupling agent), 46 parts of modified calcium strontium titanate particles (modified by perfluorosilane coupling agent) and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture. S2: The mixture is placed into a molding die and pressed into a blank. The blanking pressure is 6MPa to obtain the blank. S3: Extrude the preform from the flat die head into a sheet, and then wind it up with a winding machine. The extrusion pressure is 10MPa and the extrusion speed is 4mm / min to obtain a roll. S4: Unroll the roll and place it into a twin-roll calender, adjust the gap between the twin rolls, and wind it up with a winding machine to obtain a base film with a thickness of 150μm. S5: Place the base film obtained in S4 into a mesh bag oven for baking (to remove the extrusion aid), and then roll it up. The maximum baking temperature is 280℃ and the baking time is 30 minutes. S6: Unfold the base film obtained in S5, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then, place it in a vacuum laminator for hot pressing and sintering. The hot pressing and sintering temperature is 385℃, the holding time is 120min, and the hot pressing and sintering pressure is 5MPa. Finally, peel off the steel plate and the copper pad to obtain a PTFE-based high dielectric constant high frequency copper-clad laminate.

[0032] The dielectric layer thickness of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 1 is 0.762 mm.

[0033] The average particle size of the strontium calcium titanate particles used in Example 1 was 11 μm (obtained by mixing angular and spherical strontium calcium titanate particles in a 1:2 ratio); the Sr / (Sr+Ca) ratio in the strontium calcium titanate particles used in Example 1 was 0.45 in molar ratio.

[0034] Example 2

[0035] The manufacturing process of the PTFE-based high-dielectric-constant high-frequency copper-clad laminate in Example 2 is based on Example 1, with the difference being: S2: The mixture is filled into the mold cavity and pressed to obtain a preform at a pressure of 20 kgf / cm². 2 Hold pressure for 5 minutes; S3: The preform is rolled to obtain a green substrate, wherein the rolling pressure is 490N, the roller linear speed is 0.5m / min, and the roller gap is 150μm; the green substrate is then placed in an oven to dry and remove the extrusion aid, the maximum temperature of the oven is 280℃, and the time is 30min, to obtain the base film. S4: Lay out the base film, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then place it in a vacuum laminator for pressing. The pressing temperature is 385℃, the holding time is 120min, and the pressing pressure is 5MPa. Finally, peel off the steel plate and copper pad to obtain a PTFE-based high dielectric constant high frequency copper clad laminate.

[0036] Example 3

[0037] The manufacturing process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 3 is based on Example 1, except for S4 and S6.

[0038] S4: Unroll the roll and place it into a twin-roll calender, adjust the gap between the twin rolls, and wind it up with a winding machine to obtain a base film with a thickness of 184μm. S6: Unfold the base film obtained in S5, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then place it in a vacuum laminator for pressing. The pressing temperature is 385℃, the holding time is 120min, and the pressing pressure is 5MPa. Finally, peel off the steel plate and the copper pad to obtain a PTFE-based high dielectric constant high frequency copper clad laminate.

[0039] The dielectric layer thickness of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 3 is 0.761 mm.

[0040] Example 4

[0041] The manufacturing process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 4 is based on Example 1, except for S4 and S6.

[0042] S4: Unroll the roll and place it into a twin-roll calender, adjust the gap between the twin rolls, and wind it up with a winding machine to obtain a base film with a thickness of 236μm. S6: Unfold the base film obtained in S5, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then place it in a vacuum laminator for pressing. The pressing temperature is 385℃, the holding time is 120min, and the pressing pressure is 5MPa. Finally, peel off the steel plate and copper pad to obtain a PTFE-based high dielectric constant high frequency copper clad laminate.

[0043] The dielectric layer thickness of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 4 is 0.766 mm.

[0044] Example 5

[0045] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 5 is based on Example 1, except that the glass fiber cloth used in Example 5 is type 1035 (the thickness of the impregnated cloth was measured to be 35 μm) and the thickness of the base film obtained in S4 is 127 μm.

[0046] Example 6

[0047] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 6 is based on Example 1, except that the glass fiber cloth used in Example 6 is type 106 (the thickness of the impregnated cloth was measured to be 40 μm) and the thickness of the base film obtained in S4 is 120 μm.

[0048] Example 7

[0049] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 7 is based on Example 1, except that in S1: by mass, 40 parts of polytetrafluoroethylene powder, 60 parts of modified titanium dioxide particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0050] Example 8

[0051] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 8 is based on Example 1, except that in S1: by mass, 40 parts of polytetrafluoroethylene powder, 40 parts of modified titanium dioxide particles, 20 parts of modified calcium strontium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0052] Example 9

[0053] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 9 is based on Example 1, except that in S1: by mass, 40 parts of polytetrafluoroethylene powder, 20 parts of modified titanium dioxide particles, 40 parts of modified calcium strontium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0054] Example 10

[0055] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 10 is based on Example 1, except that in S1: by mass, 37 parts of polytetrafluoroethylene powder, 21 parts of modified titanium dioxide particles, 42 parts of modified calcium strontium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0056] Example 11

[0057] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 11 is based on Example 1, except that in S1: by mass, 34 parts of polytetrafluoroethylene powder, 22 parts of modified titanium dioxide particles, 44 parts of modified calcium strontium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0058] Example 12

[0059] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 12 is based on Example 1, except that in S1: by mass, 28 parts of polytetrafluoroethylene powder, 24 parts of modified titanium dioxide particles, 48 ​​parts of modified calcium strontium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0060] Example 13

[0061] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 13 is based on Example 1, except that in S1: by mass, 31 parts of polytetrafluoroethylene powder, 69 parts of modified strontium calcium titanate particles and 15 parts of extrusion aid are mixed and cured at 60°C for 12 hours to obtain the mixture.

[0062] Example 14

[0063] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 14 is based on Example 1, except that the Sr / (Sr+Ca) ratio in the strontium calcium titanate used in Example 14 is 0.3 in terms of molar ratio.

[0064] Example 15

[0065] The production process of the PTFE-based high dielectric constant high frequency copper clad laminate in Example 15 is based on Example 1, except that the Sr / (Sr+Ca) ratio in the strontium calcium titanate used in Example 15 is 0.6 in terms of molar ratio.

[0066] Comparative Example The comparative PTFE-based high dielectric constant high frequency copper-clad laminate is based on Example 1, except for S4 and S6.

[0067] S4: Unroll the roll and place it into a twin-roll calender, adjust the gap between the twin rolls, and wind it up with a winding machine to obtain a base film with a thickness of 125μm. S6: Unfold the base film obtained in S5, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, impregnated cloth, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then place it in a vacuum laminator for pressing. The pressing temperature is 385℃, the holding time is 120min, and the pressing pressure is 5MPa. Finally, peel off the steel plate and the copper pad to obtain a PTFE-based high dielectric constant high frequency copper clad laminate.

[0068] The dielectric layer thickness of the comparative PTFE-based high dielectric constant high frequency copper clad laminate is 0.760 mm.

[0069] 2. Detection methods for the examples and comparative samples 2.1. Determine the dielectric constant and loss factor of copper-clad laminates according to GB / T 12636-1990.

[0070] 2.2. Heat resistance test Immerse the sample board in a 288℃ solder bath for 10 seconds and then remove it. If the sample board does not delaminate and no bubbles overflow after repeating the process twice, it has good heat resistance. If the sample board does not delaminate and no bubbles overflow after repeating the process three times, it has excellent heat resistance.

[0071] 2.3. Thickness Uniformity Test Referencing the national standard GB / T 4722-2017, select 10 test points on the copper-clad laminate to measure the thickness and then calculate the standard deviation of the thickness.

[0072] 3. Performance test results of the examples and comparative samples

[0073] The copper-clad laminates in the examples and comparative examples all exhibited excellent heat resistance. Except for Example 2, where the standard deviation of thickness was 0.06 mm, the standard deviations of the comparative examples and other examples were all between 0.015 and 0.031 mm.

[0074] Data from Examples 1 and 2 show that the copper-clad laminate made from the base film produced by blanking, extrusion, and calendering has a uniform thickness.

[0075] Examples 1, 3, 4 and the comparative examples show that the preferred number of base film sheets and the number of impregnated cloth sheets are beneficial for copper clad laminates to obtain a higher dielectric constant and a lower loss factor.

[0076] Examples 1, 5, and 6 show that the preferred thickness of the impregnated cloth is beneficial for reducing the dielectric constant of the copper clad laminate.

[0077] Examples 1 and 7-13 show that the preferred mass ratio of ceramic particles to polytetrafluoroethylene resin and the preferred mass ratio of titanium dioxide to calcium strontium titanate are both beneficial for copper clad laminates to obtain higher dielectric constants and lower loss factors.

[0078] Examples 1, 14, and 15 show that the preferred molar ratio of Sr / (Sr+Ca) in calcium strontium titanate is beneficial for copper clad laminates to obtain a higher dielectric constant and a lower loss factor.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A PTFE-based high-dielectric-constant high-frequency copper-clad laminate, characterized in that, It includes a copper foil layer, a dielectric layer and a copper foil layer stacked in sequence. The dielectric layer is an alternating layer of impregnated cloth and a base film layer. The base film layer and the copper foil layer are compositely connected. The components of the impregnated cloth layer and the base film layer both include polytetrafluoroethylene resin. The thickness of the dielectric layer is T mm, and the integer part of T / 0.127 is N. The number of layers in the base film is one of N-2, N-1, and N.

2. The PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 1, characterized in that, The base film layer comprises 60-72 parts by weight of ceramic particles and 28-40 parts by weight of polytetrafluoroethylene resin.

3. The PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 2, characterized in that, The ceramic particles include titanium dioxide and calcium strontium titanate, and the mass ratio of titanium dioxide to calcium strontium titanate is 1:(1.5~2.6).

4. The PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 2, characterized in that, The ceramic particles are at least one of angular and spherical shapes, and the average particle size of the ceramic particles is 5~15μm.

5. The PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 3, characterized in that, The Sr / (Sr+Ca) ratio in the strontium calcium titanate is 0.4~0.55 in molar ratio.

6. A manufacturing process for PTFE-based high-dielectric-constant high-frequency copper-clad laminates, characterized in that, Based on the PTFE-based high dielectric constant high-frequency copper-clad laminate according to any one of claims 1 to 5, the process includes the following steps: S10: Mix polytetrafluoroethylene resin and ceramic particles, mature, form blanks, extrude into sheets, calender, and bake to obtain a base film; Fiberglass cloth is impregnated with polytetrafluoroethylene emulsion and then baked to obtain impregnated cloth. S20: Steel plate, copper pad, copper foil, alternating layers of impregnated cloth and base film, copper foil, copper pad, and steel plate are stacked in sequence, and the copper foil is bonded to the base film. S30: PTFE-based high dielectric constant high-frequency copper-clad laminate obtained by hot pressing and sintering; Furthermore, the hot pressing sintering temperature is 370~390℃, the holding time is 30~150min, and the pressure is 3~6MPa.

7. The manufacturing process of PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 6, characterized in that, The thickness of the glass fiber cloth is 10~35μm; Furthermore, the thickness of the glass fiber cloth is 10~14μm.

8. The manufacturing process of PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 7, characterized in that, The thickness of the fiberglass cloth is T. 玻纤布 μm, the thickness of the impregnated cloth is (T 玻纤布 +8)~(T 玻纤布 +16) μm.

9. The manufacturing process of PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 6, characterized in that, In S00, the pressure during the preforming step is 4~8MPa.

10. The manufacturing process of PTFE-based high-dielectric-constant high-frequency copper-clad laminate according to claim 6, characterized in that, In S00, the pressure of the extrusion step is 4~12MPa, and the speed is 0.5~5mm / min.

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