TWI695202B - High adhesive strength liquid crystal polymer laminate and the preparation method thereof - Google Patents

Abstract

A high adhesive strength liquid crystal polymer (LCP) laminate comprises at least one copper foil layer, at least one low dielectric adhesive layer, and a LCP layer, wherein the low dielectric adhesive layer is between the copper foil layer and the LCP layer and bonds them together, wherein the Dk value (10GHz) of the low dielectric adhesive layer is 2.0-4.0 and the Df value (10GHz) is 0.001-0.010, and the Dk value (10GHz) of the LCP layer is 2.5-4.0 and the Df value (10GHz) is 0.001-0.010. The LCP laminate provided by the present invention is improved the adhesive strength by adding the low dielectric adhesive layer between a copper foil layer and a LCP layer, so that a copper foil layer with a lower Rz value can be selected and hard to cause signal loss in high frequency and high speed transmission. Moreover, the low dielectric adhesive layer has low dielectric constant and dielectric loss, and is likewise beneficial for high frequency and high speed transmission.

Description

High adhesive strength liquid crystal polymer substrate and preparation method thereof

The present invention relates to the field of FPC (Flexible Printed Circuit) and its preparation technology, and particularly relates to LCP (liquid crystal polymer) single-sided and double-sided copper foil substrates.

The flexible printed circuit board has the advantages of continuous automated production, improved wiring density, flexibility, large design field, three-dimensional three-dimensional wiring, omitted connectors, and welding of wires. It is in line with the light and thin electronic products with multiple functions Demand has increased the application of FPC.

With the surge in demand for high-frequency and high-speed transmission and the coming of the 5G era, the demand for high-performance engineering plastics has increased substantially. In the past, flexible copper foil substrates were mainly made of copper foil and polyimide (PI) resin and other raw materials. However, PI films have high dielectric properties and are easy to absorb moisture, which is likely to cause signal loss under high-frequency and high-speed transmission. The liquid crystal polymer (LCP) material has characteristics such as low moisture absorption, high chemical resistance, high dimensional stability, low dielectric constant/dielectric loss factor (Dk/Df), and low dielectric loss and low water absorption The microwave and high-frequency millimeter waves have obvious advantages over traditional PI, and gradually become a new application material, which can be applied to antennas, base stations, and millimeter-wave radars.

However, compared with PI, the adhesion between LCP and copper foil is poor, so LCP substrates usually use copper foil with a rough surface and a high Rz (surface roughness) value to improve the adhesion strength. However, the skin effect during high-frequency and high-speed transmission makes the electron transmission tend to proceed on the surface of the copper foil. If the surface is rough, a large signal loss will be formed. Therefore, how to improve the bonding strength of the LCP layer and the copper foil layer, so that the copper foil with a lower Rz value can be used to reduce the signal loss when manufacturing the substrate is an important issue in the development of the LCP substrate.

Examples include the composite laminated high-frequency low-dielectric adhesive film proposed in Chinese Patent No. 205105448 U, the low-dielectric adhesive film proposed in Chinese Patent No. 205255668 U, and the high-frequency adhesive glue proposed in Chinese Patent No. 105295753 B Laminated structure and its preparation method, composite LCP high-frequency high-speed double-sided copper foil substrate proposed by Chinese Patent No. 206840863 U, composite LCP high-frequency high-speed FRCC (soft adhesive copper foil substrate) proposed by Chinese Patent No. 206932462 U Base materials, etc., have failed to effectively improve the adhesion between LCP and copper foil.

In order to meet the market demand for high-frequency high-speed flexible sheets, the LCP substrate provided by the present invention can increase the LCP layer and the copper foil layer by adding a low dielectric adhesive layer between the copper foil layer and the LCP layer and improving its formulation and performance Therefore, the copper foil layer with a lower Rz value can be used, which is not easy to cause signal loss during high-frequency high-speed transmission. In addition, the low dielectric adhesive layer has low dielectric constant and low dielectric loss, which is also conducive to High frequency and high speed transmission.

In order to solve the above technical problems, the present invention provides a high-adhesion LCP substrate comprising: at least one copper foil layer with a thickness of 1 to 35 μm; a liquid crystal polymer layer with a thickness of 12 to 75 μm; and At least one low dielectric adhesive layer, the thickness of the low dielectric adhesive layer is 1 to 7 μm, and the low dielectric adhesive layer is located between the copper foil layer and the liquid crystal polymer layer; wherein, the low dielectric adhesive layer The Dk value is 2.0 to 4.0, the Df value is 0.001 to 0.010, and the Dk value (10 GHz) of the liquid crystal polymer layer is 2.5 to 4.0, and the Df value (10 GHz) is 0.001 to 0.010; the low dielectric adhesive layer includes At least one of component A and component B, wherein the component A is selected from the group consisting of ceramic powder, sintered silica, Teflon, fluorine-based resin different from Teflon, polyetheretherketone ( PEEK) and at least one flame retardant group, the component B is selected from epoxy resin, acrylic resin, urethane resin, silicone rubber resin, parylene resin, Bismaleimide-based resin and polyimide-based resin constitute at least one of the group; the component A accounts for 0 to 50% by weight of the total solid content of the low-dielectric adhesive layer, the Component B accounts for 5 to 80% by weight of the total solid content of the low dielectric adhesive layer.

In a specific embodiment, the ceramic powder is at least one selected from the group consisting of BaTiO ₃ , SrTiO ₃ , Ba(Sr)TiO ₃ , PbTiO ₃ , CaTiO ₃ and Mg ₂ TiO ₄ .

In a specific embodiment, the ceramic powder system accounts for 0 to 45% by weight of the total solid content of the low-dielectric adhesive layer, and the sintered silica system accounts for the total solid content of the low-dielectric adhesive layer. 0% to 45% by weight, the Teflon system accounts for 0 to 45% by weight of the total solid content of the low-dielectric adhesive layer, and the fluorine-based resin system accounts for the total solid content of the low-dielectric adhesive layer 0 to 45% by weight, the polyetheretherketone (PEEK) accounts for 0 to 45% by weight of the total solid content of the low-dielectric adhesive layer, and the flame retardant accounts for the low-dielectric adhesive The total solids content of the layer is 0 to 45% by weight.

In a specific embodiment, the fluorine-based resin is selected from the group consisting of polyvinylidene fluoride, a copolymer of vinyl fluoride and vinyl ether, a copolymer of tetrafluoroethylene and ethylene, a copolymer of polychlorotrifluoroethylene and ethylene, four Vinyl fluoride, hexafluoropropylene and vinylidene fluoride copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, polyvinyl chloride, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene- At least one of the group consisting of vinyl fluoride copolymer and tetrafluoroethylene-hexafluoropropylene-trifluoroethylene copolymer.

In an embodiment, the Rz value of the surface of the copper foil layer adhered to the low-dielectric adhesive layer is 0 to 1.2 μm.

In a specific embodiment, the LCP substrate is an LCP single-sided copper foil substrate. The LCP single-sided copper foil substrate is composed of a copper foil layer, a low-dielectric adhesive layer, and an LCP layer. From the bottom, the copper foil layer, the low dielectric adhesive layer and the LCP layer are in this order; the thickness of the LCP single-sided copper foil substrate is 14 to 117 μm.

In a specific embodiment, the LCP substrate is an LCP double-sided copper foil substrate. The LCP double-sided copper foil substrate is composed of two copper foil layers, two low dielectric adhesive layers, and one LCP layer, and From top to bottom are the first copper foil layer, the first low dielectric adhesive layer, the LCP layer, the second low dielectric adhesive layer and the second copper foil layer; the thickness of the LCP double-sided copper foil substrate is 16 to 159μm.

The invention also provides a method for preparing the high-adhesive strength LCP substrate. The method for preparing the LCP single-sided copper foil substrate is as follows: Step 1. Apply the precursor of the low dielectric adhesive layer to the On the surface of the copper foil layer, the solvent is removed at 60 to 180°C to form the low-dielectric adhesive layer; step two, the precursor of the LCP layer is coated on the surface of the low-dielectric adhesive layer Above, the solvent is removed at 60 to 180°C to form the LCP layer, and an annealing treatment is performed at 240 to 260°C for 8 to 12 hours to obtain the LCP single-sided copper foil substrate.

The invention further provides a method for preparing the high-strength LCP substrate. The method for preparing the LCP double-sided copper foil substrate is one of the following two methods. The first method includes the following steps: Step 1. The precursor of the first low-dielectric adhesive layer is coated on the surface of the first copper foil layer, and the solvent is removed under the condition of 60 to 180° C. to form the first low-dielectric adhesive layer; step two, the LCP layer The precursor is coated on the surface of the first low dielectric adhesive layer, the solvent is removed at 60 to 180°C to form the LCP layer, and annealed at 240 to 260°C for 8 to 12 hours Process; Step 3: Apply the precursor of the second low-dielectric adhesive layer on the surface of the LCP layer, and remove the solvent at 60 to 180°C to form a second low-dielectric adhesive layer; and step four 2. Pressing a second copper foil layer on the second low dielectric adhesive layer and curing at 160 to 200°C for more than 5 hours to obtain the LCP double-sided copper foil substrate.

The second method includes the following steps: Step 1. The precursors of the low-dielectric adhesive layer are respectively coated on the surfaces of the two copper foil layers, and the solvent is removed at 60 to 180° C. to form two Semi-finished product A with a low-dielectric adhesive layer; step two, the precursor of the LCP layer is coated on the surface of one of the low-dielectric adhesive layers of the semi-finished product A, and the solvent is removed at 60 to 180°C; And annealed at 240 to 260°C for 8 to 12 hours to obtain a semi-finished product B with an LCP layer; Step 3: attach and merge the LCP layer of the semi-finished product B with another low-dielectric adhesive layer of the semi-finished product A Pressing and curing at 160 to 200°C for more than 5 hours to obtain the LCP double-sided copper foil substrate.

The present invention has the following beneficial effects: The LCP substrate provided by the present invention includes at least one copper foil layer, at least one low dielectric adhesive layer and an LCP layer, and the copper foil layer and the LCP layer are adhered by a low dielectric adhesive layer , By improving the formulation and performance of the low dielectric adhesive layer, the bonding strength between the low dielectric adhesive layer and the copper foil layer and the LCP layer can be improved, thereby indirectly increasing the bonding strength between the LCP layer and the copper foil layer, so In the case where the strength meets the requirements, a low-profile copper foil layer with a lower Rz value can be selected. Due to the skin effect of signal transmission, electron transmission tends to proceed on the surface of the copper foil layer, and a copper foil layer with a lower roughness is used , It will greatly reduce the signal loss, that is, it is not easy to cause signal loss during high-frequency high-speed transmission.

In addition, the low dielectric adhesive layer of the present invention has a low dielectric constant and low dielectric loss, which is also beneficial to high-frequency and high-speed transmission.

In addition, the present invention also has a low rebound force suitable for high-density assembly and excellent mechanical properties. The laser drilling process is better and the small aperture is not easy to shrink. The present invention is superior to the general LCP and PI substrates and suitable for Used in 5G smart phones, Apple watch and other wearable devices.

In addition, in the traditional preparation method of thermosetting polyimide film, a thick film with a thickness of 38 μm or more is not easy to produce, and the efficiency is low. The manufacturing method of the present invention can not only manufacture LCP single-sided and double-sided copper foil substrates with appropriate thickness, Easy to get 100μm substrate.

Furthermore, from the test data, it can be seen that the LCP substrate of the present invention has good adhesion strength and is >1.0 kgf/cm.

100‧‧‧Copper foil layer

200‧‧‧Low dielectric adhesive layer

300‧‧‧ LCP layer

FIG. 1 is a schematic diagram of the structure of the high bonding strength LCP substrate of the present invention.

FIG. 2 is a schematic structural view of another embodiment of the high-strength LCP substrate of the present invention.

The following specific embodiments are used to illustrate the disclosure content of the present invention. After reading the disclosure content of this specification, those with ordinary knowledge in the technical field can easily understand its advantages and effects.

It should be noted that the structure, ratio, size, etc. shown in the drawings of this specification are only in accordance with the contents disclosed in the specification, so that those with ordinary knowledge in the technical field can understand and read, and are not intended to limit the present invention to Under certain conditions, it has no technical significance. Any modification of structure, change of proportional relationship, or adjustment of size shall be included in the scope disclosed in this manual without affecting the functions and objectives that can be achieved in this manual. Without substantial changes to the technical content, changes or adjustments in their relative relationships should also be considered within the scope of the invention. At the same time, the terms such as "upper", "first", "second", "one" and "two" cited in this specification are only for the convenience of description, not for limiting the present invention. The scope of implementation, changes or adjustments in their relative relationship, without substantial changes in the technical content, shall also be regarded as the scope of the invention.

The high-strength LCP substrate of the present invention, as shown in FIGS. 1 and 2, includes at least one copper foil layer 100, at least one low dielectric layer 200 and an LCP layer 300, the low dielectric layer 200 is located The copper foil layer 100 and the LCP layer 300 are bonded between the copper foil layer 100 and the LCP layer 300.

In a specific embodiment, the thickness of each copper foil layer is 1 to 35 μm; the thickness of each low dielectric layer is 1 to 7 μm; the thickness of the LCP layer is 12 to 75 μm . Preferably, the thickness of each copper foil layer is 9 to 18 μm; the thickness of each low dielectric adhesive layer is 2 to 3 μm.

In a specific embodiment, the ceramic powder is at least one selected from the group consisting of BaTiO ₃ , SrTiO ₃ , Ba(Sr)TiO ₃ , PbTiO ₃ , CaTiO ₃ and Mg ₂ TiO ₄ . The ceramic powder may be doped with one or more metal ions, or may not be doped.

In a specific embodiment, the copper foil layer is a rolled copper foil layer or an electrolytic copper foil layer.

In a specific embodiment, the bonding strength between the low-dielectric adhesive layer and the copper foil layer is> 1.0 kgf/cm.

The LCP substrate in FIG. 1 is an LCP single-sided copper foil substrate. The LCP single-sided copper foil substrate is composed of a copper foil layer 100, a low-dielectric adhesive layer 200, and an LCP layer 300, in order from top to bottom. It is the copper foil layer 100, the low dielectric adhesive layer 200 and the LCP layer 300; the thickness of the LCP single-sided copper foil substrate is 14 to 117 μm.

The preparation method of the LCP single-sided copper foil substrate in FIG. 1 is for example as follows, but not limited to this: Step 1. The precursor of the low dielectric adhesive layer 200 is coated on the surface of the copper foil layer 100, Removing the solvent at 60 to 180°C to form the low-dielectric adhesive layer 200; step two, applying the precursor of the LCP layer 300 on the surface of the low-dielectric adhesive layer 200 at 60 The solvent is removed at 180°C to form the LCP layer 300, and an annealing treatment is performed at 240 to 260°C (preferably 250°C) for 8 to 12 hours (preferably 10 hours) to obtain the LCP Single-sided copper foil substrate.

Refer to FIG. 2, which is a schematic structural view of another embodiment of the LCP substrate with high bonding strength according to the present invention. The LCP substrate in FIG. 2 is an LCP double-sided copper foil substrate. The LCP double-sided copper foil substrate is composed of two copper foil layers 100, two low dielectric adhesive layers 200, and one LCP layer 300, and from top to The following are the copper foil layer 100 (as the first copper foil layer), the low dielectric layer 200 (as the first low dielectric layer), the LCP layer 300, and the low dielectric layer 200 (as the second low dielectric adhesive layer) and the copper foil layer 100 (as the second copper foil layer); the thickness of the LCP double-sided copper foil substrate is 16 to 159 μm.

The preparation method of the LCP double-sided copper foil substrate in FIG. 2 is, for example, one of the following two methods, but it is not limited to this: The first method includes the following steps: Step 1: The precursor of the low dielectric adhesive layer 200 Coated on the surface of the copper foil layer 100 (as the first copper foil layer), the solvent is removed at 60 to 180°C to form the low dielectric paste layer 200 (as the first low dielectric paste layer) ); Step two, the precursor of the LCP layer 300 is coated on the surface of the first low dielectric adhesive layer, the solvent is removed at 60 to 180 ℃ to form the LCP layer 300, and Annealing treatment is performed at 240 to 260°C (preferably 250°C) for 8 to 12 hours (preferably 10 hours); step three, the precursor of the low dielectric adhesive layer 200 is coated on the LCP layer 300 On the surface of the surface, remove the solvent at 60 to 180°C to form the low-dielectric adhesive layer 200 (as a second low-dielectric adhesive layer); Step four, press on the second low-dielectric adhesive layer The copper foil layer 100 (as the second copper foil layer) is combined and cured at 160 to 200° C. for more than 5 hours to obtain the LCP double-sided copper foil substrate.

The second method includes the following steps: Step 1. The precursors of the low-dielectric adhesive layer 200 are respectively coated on the surfaces of the two copper foil layers 100, and the solvent is removed at 60 to 180°C to form 2. Semi-finished product A with the low-dielectric adhesive layer 200; Step 2: Apply the precursor of the LCP layer 300 on the surface of one of the low-dielectric adhesive layers 200 of the semi-finished product A, at 60 to 180 Remove the solvent under the condition of ℃, and perform annealing treatment at 240 to 260 ℃ (preferably 250 ℃) for 8 to 12 hours (preferably 10 hours) to obtain the semi-finished product B with the LCP layer; The LCP layer 300 of the semi-finished product B is laminated and pressed with another low-dielectric adhesive layer 200 of the semi-finished product A, and cured at 160 to 200° C. for more than 5 hours to obtain the LCP double-sided copper foil substrate .

The invention illustrates the details through examples of the embodiments. However, the interpretation of the present invention should not be limited to the following examples.

Examples 1 to 9 use polyimide resin, ceramic powders BaTiO ₃ and SrTiO ₃ , sintered silica, Teflon, and flame retardant as components of the low-dielectric adhesive layer. The components of each example The ratio, dielectric constant Dk (10 GHz) and dielectric loss factor Df (10 GHz) are shown in Table 1 below.

Examples 1 to 4 are LCP single-sided copper foil substrates having a copper foil layer, a low dielectric adhesive layer and an LCP layer prepared according to the method provided by the present invention; Examples 5 to 9 are provided according to the present invention The method prepares an LCP double-sided copper foil substrate with two copper foil layers, two low dielectric adhesive layers and one LCP layer. Comparative Example 1 is an LCP single-sided copper foil substrate without a low-dielectric adhesive layer, and Comparative Example 2 is an LCP double-sided copper foil substrate without a low-dielectric adhesive layer.

The dielectric constant Dk (10 GHz) of the LCP layer used in Examples 1 to 9 was 2.95, and the dielectric loss factor Df (10 GHz) was 0.003.

The performance tests of Examples 1 to 9 and Comparative Examples 1 to 2 were carried out. The test method was implemented in accordance with the "Test Guidelines for Flexible Board Assembly Requirements" (TPCA-F-002), and the dielectric constant Dk (10 GHz) of each group was compared, The dielectric loss factor Df (10 GHz), adhesion strength, water absorption, and solder heat resistance are shown in Table 2 below.

It can be seen from Table 2 that the LCP substrate of the present invention has a higher bonding strength, can be made of a low-profile copper foil layer with a low Rz value, and has a low Dk/Df, which is beneficial to high-frequency high-speed transmission.

By adding a low-dielectric adhesive layer between the copper foil layer and the LCP layer and improving its formulation and performance, it can increase the adhesion strength between the LCP layer and the copper foil layer, so a copper foil layer with a lower Rz value can be used for high frequency High-speed transmission is not easy to cause signal loss. In addition, the low dielectric adhesive layer has low dielectric constant and low dielectric loss, which is also conducive to high-frequency high-speed transmission.

The above is only an embodiment of the present invention, and therefore does not limit the patent scope of the present invention. Any equivalent structure made by the description and drawings of the present invention, or directly or indirectly used in other related technical fields, are the same Included in the patent protection scope of the present invention.

100‧‧‧Copper foil layer

200‧‧‧Low dielectric adhesive layer

300‧‧‧ LCP layer

Claims (10)

A high adhesive strength liquid crystal polymer substrate, comprising: at least one copper foil layer, and the copper foil layer has a thickness of 1 to 35 μm; a liquid crystal polymer layer with a thickness of 12 to 75 μm; and at least one low dielectric adhesive layer The thickness of the low dielectric adhesive layer is 1 to 7 μm, and the low dielectric adhesive layer is located between the copper foil layer and the liquid crystal polymer layer, wherein the Dk value (10 GHz) of the low dielectric adhesive layer is 2.0 to 4.0, Df value (10 GHz) is 0.001 to 0.010, and the Dk value (10 GHz) of the liquid crystal polymer layer is 2.5 to 4.0, Df value (10 GHz) is 0.001 to 0.010, the low dielectric adhesive layer includes components A and component B, the component A includes ceramic powder and is selected from the group consisting of sintered silica, Teflon, fluorine resins other than Teflon, polyether ether ketone (PEEK) and flame retardant At least one of the group, the component B is selected from the group consisting of epoxy resin, acrylic resin, urethane resin, silicone rubber resin, parylene resin, bismaleimide resin and Polyimide-based resins constitute at least one of the groups, and the component A accounts for 0 to 50% by weight of the total solid content of the low-dielectric adhesive layer, and the component B accounts for the low-dielectric adhesive layer 5 to 80% by weight of the total solid content. The high adhesive strength liquid crystal polymer substrate as described in item 1 of the patent application range, wherein the ceramic powder is selected from the group consisting of BaTiO ₃ , SrTiO ₃ , Ba(Sr)TiO ₃ , PbTiO ₃ , CaTiO ₃ and Mg ₂ TiO ₄ At least one of the groups. The high adhesive strength liquid crystal polymer substrate as described in item 1 of the patent application range, wherein the ceramic powder system accounts for 0 to 45% by weight of the total solid content of the low dielectric adhesive layer, and the sintered silica system accounts for 0 to 45% by weight of the total solid content of the low dielectric adhesive layer, the Teflon series It accounts for 0 to 45% by weight of the total solid content of the low-dielectric adhesive layer, the fluorine-based resin accounts for 0 to 45% by weight of the total solid content of the low-dielectric adhesive layer, and the polyetheretherketone (PEEK) system The flame retardant accounts for 0 to 45% by weight of the total solid content of the low dielectric adhesive layer, and the flame retardant accounts for 0 to 45% by weight of the total solid content of the low dielectric adhesive layer. The high adhesion strength liquid crystal polymer substrate as described in item 1 of the patent application range, wherein the fluorine-based resin is selected from polyvinylidene fluoride, copolymer of vinyl fluoride and vinyl ether, copolymer of tetrafluoroethylene and ethylene , Copolymers of chlorotrifluoroethylene and ethylene, tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, tetrafluoroethylene-hexa At least one of the group consisting of fluoropropylene copolymer, ethylene-fluoroethylene copolymer and tetrafluoroethylene-hexafluoropropylene-trifluoroethylene copolymer. The liquid crystal polymer substrate with high adhesive strength as described in item 1 of the patent application range, wherein the Rz (surface roughness) value of the surface of the copper foil layer adhered to the low-dielectric adhesive layer is 0.01 to 1.2 μm. The high adhesive strength liquid crystal polymer substrate as described in item 1 of the patent application range, wherein the liquid crystal polymer substrate has a copper foil layer and a low dielectric adhesive layer, and the thickness of the liquid crystal polymer substrate is 14 to 117μm. The high adhesive strength liquid crystal polymer substrate as described in item 1 of the patent application range, wherein the liquid crystal polymer substrate has two copper foil layers and two low dielectric adhesive layers, and the thickness of the liquid crystal polymer substrate is 16 to 159 μm. A method for preparing a high adhesive strength liquid crystal polymer substrate as described in item 6 of the patent application scope includes: Coating the precursor of the low-dielectric adhesive layer on the surface of the copper foil layer, removing the solvent at 60 to 180° C. to form the low-dielectric adhesive layer; coating the precursor of the liquid crystal polymer layer Lay on the surface of the low dielectric adhesive layer, remove the solvent at 60 to 180°C to form the liquid crystal polymer layer; and anneal at 240 to 260°C for 8 to 12 hours to obtain the liquid crystal polymer Single-sided copper foil substrate. A method for preparing a high adhesive strength liquid crystal polymer substrate as described in item 7 of the patent application scope includes: coating the precursor of the first low dielectric adhesive layer on the surface of the first copper foil layer, Remove the solvent at 60 to 180°C to form the first low-dielectric adhesive layer; apply the precursor of the liquid crystal polymer layer on the surface of the first low-dielectric adhesive layer at 60 to 180°C The solvent is removed to form the liquid crystal polymer layer, and an annealing treatment is performed at 240 to 260°C for 8 to 12 hours; the precursor of the second low dielectric adhesive layer is coated on the surface of the liquid crystal polymer layer , Removing the solvent at 60 to 180°C to form the second low-dielectric adhesive layer; and pressing the second copper foil layer on the second low-dielectric adhesive layer at 160 to 200°C for 5 After curing for more than hours, a liquid crystal polymer double-sided copper foil substrate is obtained. A method for preparing a high adhesive strength liquid crystal polymer substrate as described in item 7 of the patent application scope includes: coating the precursor of the low-dielectric adhesive layer on the surface of two copper foil layers at 60 Remove the solvent under the condition of 180℃ to form two semi-finished products A with the low dielectric adhesive layer; The precursor of the liquid crystal polymer layer is coated on the surface of one of the low-dielectric adhesive layers of the semi-finished product A, the solvent is removed under the condition of 60 to 180°C, and it is carried out under the condition of 240 to 260°C for 8 to 12 hours Annealing to obtain the semi-finished product B with the liquid crystal polymer layer; and bonding and pressing the liquid crystal polymer layer of the semi-finished product B with another low-dielectric adhesive layer of the semi-finished product A at 160 to 200°C After curing for more than 5 hours, a liquid crystal polymer double-sided copper foil substrate is obtained.

Images