WO2023109440A1 - 一种覆铜板及其制备方法 - Google Patents

一种覆铜板及其制备方法 Download PDF

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Publication number
WO2023109440A1
WO2023109440A1 PCT/CN2022/133330 CN2022133330W WO2023109440A1 WO 2023109440 A1 WO2023109440 A1 WO 2023109440A1 CN 2022133330 W CN2022133330 W CN 2022133330W WO 2023109440 A1 WO2023109440 A1 WO 2023109440A1
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Prior art keywords
film
fluororesin
clad laminate
expanded
copper clad
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PCT/CN2022/133330
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English (en)
French (fr)
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万里鹏
高峰
蔡黎
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华为技术有限公司
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Publication of WO2023109440A1 publication Critical patent/WO2023109440A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/082—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising vinyl resins; comprising acrylic resins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/085—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B32B27/322—Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/06—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the heating method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • B32B37/1018—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure using only vacuum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0012—Mechanical treatment, e.g. roughening, deforming, stretching
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/08—Impregnating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/16—Drying; Softening; Cleaning
    • B32B38/164—Drying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
    • H05K1/056—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an organic insulating layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/022—Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/02—Composition of the impregnated, bonded or embedded layer
    • B32B2260/021—Fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/04—Impregnation, embedding, or binder material
    • B32B2260/046—Synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/10—Inorganic fibres
    • B32B2262/101—Glass fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/734—Dimensional stability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/08—PCBs, i.e. printed circuit boards

Definitions

  • the present application relates to the technical field of circuit boards, in particular to a copper clad laminate and a preparation method thereof.
  • flexible printed circuit board (Flexible Printed Circuit Board; FPC) plays a key connection role in electronic equipment, and copper clad laminate (Copper Clad Laminate; CCL), as the basic plate of flexible printed circuit board, has a wide range of applications in electronic equipment. Applications.
  • copper clad laminates are mostly made of wood pulp paper or glass fiber cloth, etc., and fluororesin layers are formed on the surfaces of both sides, and the common ones can be polytetrafluoroethylene resin layers.
  • the copper clad laminate uses glass fiber cloth as the substrate. After the polytetrafluoroethylene resin film is formed, the polytetrafluoroethylene resin film is laminated on the opposite sides of the glass fiber cloth, and the polytetrafluoroethylene resin film faces away from the glass fiber. Copper foil is laminated on one side of the cloth, and then a copper clad laminate is formed by thermal pressing.
  • fluororesin is a thermoplastic material, and the thermal expansion coefficient of the formed copper clad laminate is high, and the dielectric constant value is low, and the dielectric loss value is high, which makes the insertion loss of the copper clad laminate larger and affects its performance.
  • This application provides a copper clad laminate and its preparation method, which solves the problem that the existing copper clad laminate has a high thermal expansion coefficient, a low dielectric constant value, and a high dielectric loss value, which causes a large insertion loss of the copper clad laminate and affects its performance.
  • the problem is a copper clad laminate and its preparation method, which solves the problem that the existing copper clad laminate has a high thermal expansion coefficient, a low dielectric constant value, and a high dielectric loss value, which causes a large insertion loss of the copper clad laminate and affects its performance. The problem.
  • the first aspect of the present application provides a copper clad laminate, including a substrate, an expanded fluororesin film, a first fluororesin emulsion film, and a copper foil layer;
  • the first fluororesin emulsion film is provided on the two opposite surfaces of the substrate;
  • the expanded fluororesin film is provided on the side of the first fluororesin emulsion film facing away from the substrate, and the expanded fluororesin film has a plurality of microporous structures;
  • the copper foil layer is arranged on the side of the expanded fluororesin film facing away from the substrate.
  • the middle layer of the copper clad laminate (with the substrate as the center, the substrate and the film layer on it can be used as the middle layer) is a film layer with a higher Dk value and Df value, and the upper and lower sides of the middle layer use the Dk value.
  • the copper clad laminate has a higher Dk value and a lower Df value as a whole, which effectively improves the performance of the copper clad laminate.
  • two layers of high dimensional stability film layers on the upper and lower sides can effectively reduce the thermal expansion and contraction of the copper clad laminate, reduce the dimensional deformation of the copper clad laminate, and improve the overall dimensional stability of the copper clad laminate.
  • the obtained copper clad laminate can reach Dk ⁇ 2.8, Df ⁇ 0.0008 (under the frequency test condition of 10GHz), Ds ⁇ 1000ppm, and the CTE of the copper clad laminate can reach 20-25ppm. While improving the performance of the copper clad laminate, the copper clad laminate is also improved. Dimensional stability.
  • the expanded fluororesin membrane includes an expanded base membrane and a filled membrane, and the microporous structure is located in the expanded base membrane;
  • the filling membranes are located on opposite sides of the expanded base membrane respectively, and the filling membranes fill the microporous structure.
  • the filling film can effectively reduce the porosity of the puffed base film, thereby reducing the overall porosity of the copper clad laminate, thereby improving the solvent resistance of the copper clad laminate, and further ensuring the performance of the copper clad laminate.
  • the filling film is a fluororesin film, and the fluororesin film is arranged on the expansion base film.
  • the fluororesin film is superimposed on the expanded base film, and the fluororesin film and the expanded base film are pressed together during the pressing process of the copper clad laminate, and the fluororesin film is filled into the microporous structure of the expanded base film, which is simple and convenient to operate , and has a better filling effect on the expanded base film, which helps to further reduce the dimensional deformation of the copper clad laminate.
  • a fluororesin film is arranged between the copper foil layer and the expanded base film, which helps to improve the bonding fastness between the copper foil layer and the expanded base film, reduces the surface deformation of the copper clad laminate, and further improves the dimensional stability of the copper clad laminate .
  • the filling film is a second fluororesin emulsion film.
  • the second fluororesin emulsion is formed into a film on the expanded base film to form the second fluororesin emulsion film, it will be filled into the micropore structure of the expanded base film, and the structure is simple and easy to realize.
  • a fluororesin film is further included, and the fluororesin film is arranged on a side of the second fluororesin emulsion film facing away from the expanded base film. That is, a fluororesin film is arranged between the copper foil layer and the second fluororesin emulsion film, and between the second fluororesin emulsion film and the first fluororesin emulsion film, which helps to lift the copper foil layer and the expanded fluororesin film.
  • a reinforcement is further included, and the reinforcement is arranged in the first fluororesin emulsion film.
  • the reinforcing member may be a reinforcing filler such as ceramics or titanium dioxide, which helps to improve the strength of the first fluororesin emulsion film, thereby helping to improve the dimensional stability of the copper clad laminate.
  • the Dk value and Df value of the first fluororesin emulsion film can also be adjusted through the ratio of the reinforcement to meet the high Dk value and low Df value requirements of the copper clad laminate.
  • the molding materials of the expanded base film, the filling film, and the first fluororesin emulsion film at least include: polytetrafluoroethylene, fusible polytetrafluoroethylene or perfluoroethylene Propylene copolymer.
  • the substrate includes at least glass fiber cloth.
  • Glass fiber cloth has a lower cost and helps to improve the dimensional stability of the overall and surface layers of the copper clad laminate, thereby helping to reduce the dimensional expansion and contraction of the copper clad laminate.
  • a second aspect of the present application provides a method for preparing a copper clad laminate, the method comprising:
  • the expanded fluororesin membrane has a plurality of microporous structures
  • the copper clad laminate has a high Dk value, a low Df value, and low expansion and contraction. While improving the performance of the copper clad laminate, the copper clad laminate has better dimensional stability, thereby improving the flexibility of the flexible circuit board. electrical performance and stability.
  • the expanded fluororesin membrane includes an expanded base membrane and a filling membrane, the microporous structure is located in the expanded base membrane, and the filling membrane is used to fill the microporous structure;
  • Said obtaining said expanded resin film comprises:
  • Filling films are arranged on opposite sides of the expanded base film.
  • the filling film is filled into the microporous structure, which can reduce the porosity of the copper clad laminate, improve the performance of the copper clad laminate, and make it have better dimensional stability and solvent resistance.
  • the filling film is a fluororesin film.
  • the method is simple to operate, and while improving the performance of the copper clad laminate, it also has good dimensional stability, further reduces the void ratio of the copper clad laminate, and can further ensure the solvent resistance of the copper clad laminate.
  • the method is simple to operate and has good applicability.
  • the filling film is a second fluororesin emulsion film
  • Said arranging filling films on opposite sides of said puffed base film comprises:
  • a second fluororesin emulsion is obtained, and the expanded base film is immersed in the second fluororesin emulsion to form a second fluororesin emulsion film on opposite sides of the expanded base film.
  • the method is simple and easy to realize, and while improving the performance of the copper-clad laminate, it has better dimensional stability and solvent-proof performance.
  • the copper clad laminate further includes a fluororesin film, and after the expanded fluororesin film is disposed on the side of the first fluororesin emulsion film facing away from the substrate, the Methods also include:
  • a fluororesin film is provided, and the fluororesin film is disposed on a side of the second fluororesin emulsion film facing away from the expanded base film.
  • fluororesin film is set between the second fluororesin emulsion film and the copper foil layer, and the second fluororesin emulsion film and the first fluororesin emulsion film by above-mentioned steps method, and fluororesin film can promote the distance between each film layer Combined with fastness, further reducing the dimensional deformation of copper clad laminates.
  • the first fluororesin emulsion after obtaining the first fluororesin emulsion, it also includes:
  • a reinforcement is added to the first fluororesin emulsion.
  • the copper foil layer after providing the copper foil layer, it further includes:
  • Fluoride treatment is performed on the roughened surface of the copper foil layer.
  • the copper foil layer is roughened, and then fluorinated, which can increase the fluorine content on the surface of the copper foil layer, so that the surface of the copper foil layer has a certain amount of fluorine, which can improve the gap between the copper foil layer and the expanded fluororesin film.
  • Excellent bonding strength helps to improve the overall dimensional stability of the copper clad laminate.
  • a third aspect of the present application further provides a flexible circuit board, comprising at least a circuit structure and any one of the above copper clad laminates, the circuit structure being arranged on the copper clad laminate.
  • the electrical performance and stability of the flexible circuit board can be effectively improved.
  • the fourth aspect of the present application further provides an electronic device, which at least includes a casing and the above-mentioned flexible circuit board, and the flexible circuit board is arranged in the casing.
  • FIG. 1 is a schematic structural view of a copper clad laminate provided in an embodiment of the present application
  • FIG. 2 is a schematic cross-sectional view of a copper clad laminate in the prior art
  • Fig. 3 is a schematic diagram of the cross-sectional structure of the copper clad laminate along the A-A line in Fig. 1;
  • FIG. 4 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 1 of the present application;
  • FIG. 5 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 2 of the present application.
  • FIG. 6 is a flow chart of a method for preparing a copper-clad laminate provided in Embodiment 2 of the present application.
  • FIG. 7 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 3 of the present application.
  • FIG. 8 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 3 of the present application.
  • FIG. 9 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 4 of the present application.
  • FIG. 10 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 4 of the present application.
  • FIG. 11 is a schematic cross-sectional view of a copper clad laminate provided in Embodiment 5 of the present application.
  • FIG. 12 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 5 of the present application.
  • FIG. 1 is a schematic structural diagram of a copper clad laminate provided in an embodiment of the present application.
  • the copper clad laminate may be the basic board material of the printed circuit board (Printed Circuit Board; PCB), also called the base material.
  • a circuit structure may be provided on the copper clad laminate 100 to form a flexible printed circuit board.
  • the flexible circuit board can be applied to flexible architecture products of electronic equipment, such as in-board jumpers, board-to-board connections, and packaging of flexible boards and other flexible connection scenarios.
  • Electronic devices can include but are not limited to mobile phones, tablet computers, notebook computers, ultra-mobile personal computers (UMPC), handheld computers, touch TVs, walkie-talkies, netbooks, POS machines, personal digital assistants (personal digital assistants) assistant, PDA), wearable devices, virtual reality devices and other fixed terminals or mobile terminals.
  • UMPC ultra-mobile personal computers
  • PDA personal digital assistants
  • wearable devices virtual reality devices and other fixed terminals or mobile terminals.
  • the electrical performance requirements of the flexible circuit board formed by the copper clad laminate are generally higher, and it is required to have a lower insertion loss value, for example, to be kept within 0.4dB/inch.
  • the electrical performance of the flexible circuit board is closely related to the performance of the copper clad laminate. Therefore, after the copper clad laminate is obtained, its performance will be tested and measured.
  • the judgment standard mainly includes the dielectric constant of the copper clad laminate (Dielectronic Constant; Dk) and the dielectric loss (Dielectronic Fonstant; Df) of the copper clad laminate.
  • the dielectric constant Dk means that the medium will generate induced charges and weaken the electric field when the electric field is applied.
  • the ratio of the electric field reduction in the medium to the original applied electric field (in vacuum) is the relative permittivity, and the Dk value is a measure The macroscopic physical quantity of dielectric polarization degree. The larger the Dk value, the stronger the ability of the surface to bind charges, the less likely the charges are to be polarized, the weaker the polarization electric field, and the better the insulating properties of the material.
  • Dielectric loss Df refers to the phase difference between the current phasor and the voltage phasor flowing in the dielectric due to the hysteresis effect of the dielectric conductance and the dielectric polarization in the alternating electric field, that is, A certain phase angle is formed, and the tangent value of this phase angle is the dielectric loss Df.
  • the higher the Df value the more obvious the hysteresis effect of dielectric conductance and dielectric polarization, and the more power loss or signal loss.
  • dimensional stability refers to the property that the external dimensions of the material do not change under the action of mechanical force, heat or other external conditions.
  • Ds Dimension Stability Properties
  • FIG. 2 is a schematic cross-sectional view of a copper clad laminate in the prior art.
  • copper clad laminates are mostly made of wood pulp paper or glass fiber cloth as a reinforced substrate, and resin layers are arranged on both sides of the substrate, and then covered with copper foil, which is formed after hot pressing.
  • the more commonly used resin layer material in copper-clad laminates is fluororesin, such as polytetrafluoroethylene resin, for example, see Figure 2, a polytetrafluoroethylene copper-clad laminate proposed in the The resin film 2 is directly arranged on the glass fiber cloth 1, covered with a copper foil layer 3, and obtained by thermocompression.
  • the thermal expansion coefficient (Coefficient of Thermal Expansion; CTE) of the copper clad laminate is relatively large, and the thermal expansion and contraction of the copper clad laminate will affect its dimensional stability. Therefore, thermal expansion and contraction, dielectric Constant and dielectric loss become the main indicators to judge the performance of fluororesin type copper clad laminate.
  • the copper-clad laminate obtained by directly pressing the polytetrafluoroethylene resin onto the glass fiber cloth by thermocompression has poor dimensional stability (higher Ds value), the dimensional expansion and contraction of the copper-clad laminate are serious, and the electrical properties
  • the control range is small, the Dk value is low, and the Df value is high, so that the insertion loss of the copper clad laminate is large, and the overall performance of the copper clad laminate is poor.
  • the embodiment of the present application provides a copper clad laminate with small dimensional expansion (coefficient of thermal expansion CTE between 20-25ppm, Ds ⁇ 1500ppm), and its Dk value is relatively high (Dk ⁇ 3), and its Df value is low (Df ⁇ 0.0008), which effectively improves the performance of the copper clad laminate and helps to improve the electrical performance of the flexible circuit board.
  • FIG. 3 is a schematic cross-sectional structure diagram of the copper clad laminate in FIG. 1 along line A-A.
  • the copper clad laminate 100 includes a substrate 10, and the substrate 10 includes at least glass fiber cloth.
  • the substrate 10 can be a glass fiber cloth with a specification of 1080, and its nominal thickness can be 0.053 mm, and the unit The areal mass may be 46.8 g/m 2 .
  • the glass fiber cloth can effectively improve the dimensional stability of the overall and surface layer of the copper clad laminate 100 , thereby helping to reduce the dimensional expansion and contraction of the copper clad laminate 100 .
  • the substrate 10 may also be a board formed of other reinforcing materials such as organic fiber cloth, fluororesin film layer, polyimide film layer and the like.
  • the copper clad laminate 100 also includes a first fluororesin emulsion film 30, and the first fluororesin emulsion film 30 is disposed on opposite sides of the substrate 10.
  • the first fluororesin emulsion film 30 may be obtained by immersing the substrate 10 in the first fluorine In the resin emulsion, film layers are formed on the two opposite surfaces of the substrate 10 . That is to say, the first fluororesin emulsion film is formed on the surface of the substrate 10 by dipping, so that the first fluororesin emulsion film 30 is formed on the surface of the substrate 10 .
  • the forming material of the first fluororesin emulsion film 30 can be polytetrafluoroethylene (Polytetrafluoroethylene; PTFE), or, in some examples, the forming material of the first fluororesin emulsion film 30 can be other types of fluorine-containing resins, For example, it may be meltable polytetrafluoroethylene (Polytetrafluoroethylene; PFA) or perfluoroethylene propylene copolymer (Fluorinated ethylene propylene; FEP).
  • Polytetrafluoroethylene Polytetrafluoroethylene
  • PFA polytetrafluoroethylene
  • FEP perfluoroethylene propylene copolymer
  • a reinforcement can be arranged in the first fluororesin emulsion film, and the reinforcement can be ceramic, titanium dioxide, barium strontate and other reinforcing fillers.
  • reinforcements can be added to the first fluororesin emulsion.
  • the reinforcements are distributed in the first fluororesin emulsion film 30, which helps to improve the first fluororesin emulsion film 30.
  • the strength of the fluororesin emulsion film 30 further helps to improve the dimensional stability of the copper clad laminate 100 .
  • the Dk value and Df value of the first fluororesin emulsion film 30 can also be adjusted through the ratio of the reinforcement, so as to meet the requirements of high Dk value and low Df value of the copper clad laminate 100 .
  • the copper clad laminate 100 further includes an expanded fluororesin film 20 and a copper foil layer 40 , and the expanded fluororesin film 20 is disposed on the side of the first fluororesin emulsion film 30 facing away from the substrate 10 .
  • the expanded fluororesin membrane 20 refers to a fluororesin membrane with a plurality of microporous structures formed on the membrane layer, and has a predetermined porosity. Most of them are obtained by processing dry powder fluororesin.
  • the dry powder fluororesin is treated with solvents such as paraffin wax and perfluorooctanoic acid ammonium, it is stretched to a certain porosity by single/double-axis rolling on a calender, so as to obtain expanded fluororesin. film layer.
  • solvents such as paraffin wax and perfluorooctanoic acid ammonium
  • the first fluororesin emulsion film 30 is all arranged on the opposite sides of the substrate 10, as shown in Fig. Expanded fluororesin films 20 are respectively provided on the side of 30 facing away from the substrate, that is, the copper clad laminate 100 includes two layers of expanded fluororesin films 20 .
  • the Dk value and Df value of the expanded fluororesin film 20 can also be adjusted through the film-forming process of dry powder fluororesin.
  • fillers such as silicon dioxide, titanium dioxide and other inorganic oxide fillers
  • fillers are added when the expanded fluororesin film 20 is formed into a film, that is to say, fillers are added to the dry powder fluororesin, and the ratio of the filler to the dry powder fluororesin can be adjusted.
  • the film forming process can realize the adjustment and control of the porosity of the expanded fluororesin film 20, and then adjust the overall porosity of the copper clad laminate 100 to ensure that the void ratio of the copper clad laminate 100 is 0%, thereby improving the solvent resistance of the copper clad laminate 100 performance, to ensure the performance of the copper clad laminate 100.
  • the expanded fluororesin membrane 20 is a film layer formed by a single fluororesin film, and the formed film layer is stretched and expanded to form a microporous structure, such as an expanded fluororesin membrane 20 is the film layer formed by direct processing of dry powder fluororesin.
  • the expanded fluororesin membrane 20 may be a composite membrane of a single fluororesin membrane layer with a microporous structure and other membrane layers (such as filled membranes, etc.).
  • the molding material of the expanded fluororesin film 20 may be polytetrafluoroethylene, or other types of fluorine-containing resins, such as fusible polytetrafluoroethylene or perfluoroethylene propylene copolymer.
  • the molding material of the expanded fluororesin film 20 can be the same as that of the first fluororesin emulsion film 30, for example, both the expanded fluororesin film 20 and the first fluororesin emulsion film 30 can be polytetrafluoroethylene films, or both The molding materials can also be different.
  • the copper foil layer 40 is disposed on the side of the expanded fluororesin film 20 facing away from the substrate 10 , specifically, the copper foil layers 40 are respectively stacked on the side of the expanded fluororesin film 20 facing away from the substrate 10 to form a copper clad laminate 100 .
  • the intermediate layer (with the substrate 10 as the center, and the substrate 10 and the film layer on it can be used as the intermediate layer) is a film with a higher Dk value and a higher Df value.
  • layer, and the upper and lower sides of the middle layer are film layers with low Dk and Df values and good dimensional stability (low Ds value).
  • the overall copper clad laminate 100 has a higher Dk value and a lower Df value, which effectively improves the performance of the copper clad laminate 100 .
  • the two layers of high dimensional stability film layers on the upper and lower sides can effectively reduce the thermal expansion and contraction of the copper clad laminate 100, reduce the dimensional deformation of the copper clad laminate 100, and improve the overall dimensional stability of the copper clad laminate 100.
  • Table 1 below shows the combination of the expanded fluororesin film and the first fluororesin emulsion film included in the copper-clad laminate in one example
  • Table 2 shows the performance of the copper-clad laminate obtained in one example.
  • the combination ratio of the expanded fluororesin film 20 refers to the sum of the film thicknesses of the two layers of expanded fluororesin film 20 located on the upper and lower sides of the substrate 10.
  • the combination ratio of the first fluororesin emulsion film 30 refers to the sum of film thicknesses of the two layers of the first fluororesin emulsion film 30 located on the upper and lower sides of the substrate 10 .
  • Table 1 is a performance table of a film layer in a copper clad laminate provided in Example 1 of the present application
  • Table 2 is a performance table of a copper clad laminate provided in Embodiment 1 of the present application.
  • the first fluororesin emulsion film 30 with high Dk value and Df value formed on the surface of the substrate 10 is used as the middle layer of the copper clad laminate 100 by dipping the surface of the substrate 10, and the lower Dk value and Df value are set on the upper and lower sides of the middle layer.
  • the copper clad laminate 100 can reach Dk ⁇ 2.8, Df ⁇ 0.0008 (under the frequency test condition of 10GHz), Ds ⁇ 1000ppm, and the CTE of the copper clad laminate 100 can reach 20- 25ppm, forming a copper clad laminate 100 with high Dk value, low Df value, and low expansion and shrinkage, effectively improving the performance of the copper clad laminate 100 and improving the dimensional stability of the copper clad laminate 100.
  • FIG. 4 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 1 of the present application.
  • the embodiment of the present application also provides a method for preparing a copper clad laminate. Specifically, the method includes the following steps:
  • S102 Obtain a first fluororesin emulsion, and immerse the substrate in the first fluororesin emulsion to form a first fluororesin emulsion film on opposite surfaces of the substrate.
  • additives can be added to the first fluororesin emulsion according to a certain ratio, then stirred by a high-speed mixer, and homogenized before being used.
  • the additives may be organic solvents such as ether and formaldehyde.
  • the substrate is immersed in the first fluororesin emulsion.
  • the spare first fluororesin emulsion can be added to the dipping tank of the gluing machine, and the substrate is passed through the dipping tank to realize the immersion of the substrate in the first fluororesin emulsion. .
  • the amount of the first fluororesin emulsion impregnated on the substrate can be controlled by a squeegee stick, thereby controlling the thickness of the first fluororesin emulsion film formed on the surface of the substrate.
  • the substrate impregnated with the first fluororesin emulsion can be dried, for example, the substrate can be dried in an oven to remove additives, thereby forming a first fluororesin emulsion film on the surface of the substrate.
  • the expanded fluororesin film has multiple microporous structures.
  • the film-forming method of the expanded fluororesin film can be as follows: the dry powder fluororesin is treated with a solvent, and then stretched into a film by uniaxial/biaxial rolling of a calender. , the porosity of the expanded fluororesin membrane can be controlled by adjusting its film-forming process, that is, the Dk and Df values of the expanded fluororesin membrane can be adjusted.
  • the solvent may be paraffin, ammonium perfluorooctanoate and the like.
  • each layer of the first fluororesin emulsion film is provided with an expanded fluororesin film on the side facing away from the substrate.
  • S105 providing a copper foil layer, and disposing the copper foil layer on the side of the expanded fluororesin film facing away from the substrate.
  • a copper foil layer is superimposed on the expanded fluororesin film.
  • a copper foil layer is stacked on the side of each layer of expanded fluororesin film facing away from the substrate.
  • the method may further include:
  • Fluoride treatment is performed on the surface of the roughened copper foil layer.
  • the copper foil layer is roughened, and then fluorinated, which can increase the fluorine content on the surface of the copper foil layer, so that the surface of the copper foil layer has a certain amount of fluorine, which can improve the gap between the copper foil layer and the expanded fluororesin film.
  • Excellent bonding strength helps to improve the overall dimensional stability of the copper clad laminate.
  • the pressing can be realized by a vacuum press, that is, after the copper foil layer, the expanded fluororesin film, the first fluororesin emulsion film and the substrate are stacked according to the above steps, the vacuum press is automatically adjusted under vacuum, high pressure and high temperature. Pressing, and then cooling down and dismantling the board can obtain the copper clad laminate.
  • a copper clad laminate with a Dk value, a low Df value, and low expansion and shrinkage can be obtained, which improves the performance of the copper clad laminate and makes it have high dimensional stability, thereby improving the electrical performance and stability of the flexible circuit board.
  • FIG. 5 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 2 of the present application.
  • the expanded fluororesin film 20 includes an expanded base film 21 and a filling film 22, that is to say, the expanded fluororesin film 20 is an expanded base film 21 Composite film layer with filling film 22.
  • the expanded base film 21 may be the same as the expanded fluororesin film 20 in the first embodiment, which is a single fluororesin film layer with a microporous structure and a preset porosity.
  • the expanded base film 21 can be obtained by processing dry powder fluororesin into a film, and the expanded fluororesin base film has relatively low Dk and Df values, and has good dimensional stability.
  • the filling film 22 can be any fluorine-containing film layer, the microporous structure is located in the expanded base film 21, the filled film 22 is respectively located on the opposite sides of the expanded base film 21, and the filled film 22 is filled with a microporous structure, so that the filled film 22 is It can effectively reduce the porosity of the expanded base film 21 , thereby reducing the overall porosity of the copper clad laminate 100 , thereby improving the solvent resistance of the copper clad laminate 100 and further improving the performance of the copper clad laminate 100 .
  • the middle layer is still the substrate 10 with the first fluororesin emulsion film 30 disposed on both sides, which has relatively high Dk and Df values.
  • An expanded base film 21 with a filling film 22 is arranged on the side, which maintains a low Dk value and a Df value, and good dimensional stability, and also has a low void ratio.
  • the copper clad laminate has a high Dk value, a low Df value, and low expansion and contraction performance as a whole, while improving the performance of the copper clad laminate 100, reducing the size deformation of the copper clad laminate 100, and improving the solvent resistance of the copper clad laminate 100.
  • the molding material of the filling film 22 can be polytetrafluoroethylene, or, in some examples, the molding material of the filling film 22 can also be other types of fluorine-containing resins, for example, the filling film 22 can be fusible polytetrafluoroethylene. Fluoroethylene or perfluoroethylene propylene copolymers.
  • the molding material of the filling film 22 may be the same as that of the first fluororesin emulsion film 30 and the expansion base film 21, or the molding materials of the three may be different.
  • the combination mode of the expanded fluororesin film 20 and the first fluororesin emulsion film 30 is shown in Table 1 of the first embodiment.
  • the performance of 100 is the same, that is, the Df value of CCL 100 is 0.0005, the Dk value of CCL 100 is 3, the thickness of CCL 100 is 6mil, and the porosity of CCL 100 is 0%.
  • the expanded fluororesin film 20 include the expanded base film 21 and the filled film 22, form the first fluororesin emulsion film 30 with high Dk value and Df value on the surface of the substrate 10 by dipping as the middle layer of the copper clad laminate 100, in The puffed base film 21 with the filling film 22 is superimposed on the upper and lower sides of the middle layer.
  • the film layers on the upper and lower sides of the middle layer still have low Dk value and Df value, and have good dimensional stability, so that the copper clad laminate 100 can reach Dk ⁇ 2.8, Df ⁇ 0.0008, Ds ⁇ 1000ppm, the CTE of the copper clad laminate 100 reaches 20-25ppm, and the void ratio of the copper clad laminate 100 is 0%. That is, the copper clad laminate 100 has a high Dk value, a low Df value, low expansion and shrinkage, and high solvent resistance.
  • FIG. 6 is a flow chart of a method for preparing a copper-clad laminate provided in Embodiment 2 of the present application.
  • step S103 obtaining an expanded resin film, specifically includes:
  • Filling films are arranged on opposite sides of the expanded base film.
  • the filled film when the copper clad laminate is formed by pressing, the filled film will be pressed with the expanded base film, and the filled film will fill the microporous structure of the expanded base film, thereby forming an expanded fluororesin film.
  • the preparation method of the copper clad laminate includes:
  • S202 Obtain a first fluororesin emulsion, and immerse the substrate in the first fluororesin emulsion to form a first fluororesin emulsion film on opposite surfaces of the substrate.
  • the molding method of the expanded base film may be the same as that of the expanded fluororesin film in the first embodiment, see the first embodiment for details, and will not be repeated in this embodiment.
  • the filled film can be formed first and then placed on opposite sides of the expanded base film, or the filled film can also be formed by dipping the expanded base film into the emulsion on the surface of the filled film.
  • the expanded base film with filling films on both sides is set on the first fluororesin emulsion film.
  • S206 Provide a copper foil layer, and arrange the copper foil layer on the side of the expanded fluororesin film facing away from the substrate.
  • FIG. 7 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 3 of the present application.
  • the filling film 22 is a second fluororesin emulsion film 22a
  • the second fluororesin emulsion film 22a can be an expanded base film 21 immersed in a second fluorine resin. resin emulsion, thereby forming a film layer on the surface of the expanded base film 21 . That is to say, the second fluororesin emulsion can be formed into a film on the surface of the expanded base film 21 by dipping, so as to form the second fluororesin emulsion film 22 a on the expanded base film 21 .
  • the second fluororesin emulsion film 22a will be filled into the microporous structure of the expanded base film 21, thereby reducing the porosity of the expanded base film 21, that is, The overall porosity of the copper clad laminate 100 is reduced, and the solvent resistance of the copper clad laminate 100 is improved.
  • the molding material and molding method of the second fluororesin emulsion film 22a can be the same as that of the first fluororesin emulsion film 30, for example, a reinforcing member can be added to the second fluororesin emulsion, so that when the second fluororesin emulsion is formed into a film, , so that the reinforcements are distributed in the second fluororesin emulsion film 22a to further improve the dimensional stability of the expanded fluororesin film 20 .
  • additives may also be added to the second fluororesin emulsion.
  • no reinforcement may be added to the second fluororesin emulsion, and the amount of additives added to the second fluororesin emulsion may also be reduced.
  • the combination of the expanded fluororesin film 20 and the first fluororesin emulsion film 30 is shown in Table 1 of Embodiment 1.
  • the performance of the obtained copper clad laminate 100 can also reach the same performance as that of the copper clad laminate 100 in the first embodiment, that is, the Df value of the copper clad laminate 100 is 0.0005, and the Dk value of the copper clad laminate 100 is 3.
  • the thickness of the copper plate 100 is 6mil, and the porosity of the copper clad laminate 100 is 0%.
  • the filling film 22 a second fluororesin emulsion film 22a, and form the second fluororesin emulsion film 22a on the surface of the expanded base film 21 by dipping to form the expanded fluororesin film 20, and make the middle layer the first
  • the fluororesin emulsion film 30, the above-mentioned expanded fluororesin film 20 is superimposed on the upper and lower sides of the middle layer, and the obtained copper clad laminate 100 can reach Dk ⁇ 2.8, Df ⁇ 0.0008, Ds ⁇ 1000ppm, and the CTE of the copper clad laminate 100 can reach 20-25ppm, And the porosity of the copper clad laminate 100 is 0%. That is, the copper clad laminate 100 has a high Dk value, a low Df value, low expansion and shrinkage, and high solvent resistance.
  • FIG. 8 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 3 of the present application.
  • step S204 arranging filling films on the opposite sides of the puffed base film, specifically including:
  • the second fluororesin emulsion is obtained, and the expanded base film is immersed in the second fluororesin emulsion to form the second fluororesin emulsion film on the opposite sides of the expanded base film.
  • the second fluororesin emulsion When impregnating, the second fluororesin emulsion can be added to the dipping tank of the glue machine, so that the puffed base film passes through the dipping tank, and the amount of the second fluororesin emulsion impregnated on the puffed substrate is controlled by a scraping stick. Furthermore, the thickness of the second fluororesin emulsion film formed on the surface of the expanded base film is controlled. After the impregnation is completed, the puff impregnated with the second fluororesin emulsion can be dried to form a second fluororesin emulsion film on the surface of the puff base film.
  • the preparation method of the copper clad laminate includes:
  • S302 Obtain a first fluororesin emulsion, and immerse the substrate in the first fluororesin emulsion to form a first fluororesin emulsion film on opposite surfaces of the substrate.
  • S304 Obtain a second fluororesin emulsion, and immerse the expanded base film in the second fluororesin emulsion to form a second fluororesin emulsion film on opposite sides of the expanded base film.
  • the expanded base film and the second fluororesin emulsion films arranged on opposite sides of the expanded base film jointly form an expanded fluororesin film.
  • the expanded base film with the second fluororesin emulsion film formed on both sides is arranged on the first fluororesin emulsion film.
  • S306 Provide a copper foil layer, and arrange the copper foil layer on the side of the expanded fluororesin film facing away from the substrate.
  • a copper clad laminate with a Dk value, a low Df value, and low expansion and contraction can be obtained. While improving the performance of the copper clad laminate, it has high dimensional stability and solvent resistance, thereby improving the electrical properties of the flexible circuit board. and stability, and the method is simple and easy to implement.
  • FIG. 9 is a schematic cross-sectional structure diagram of a copper clad laminate provided in Embodiment 4 of the present application.
  • the filling film 22 is a fluororesin film 22b, and the filling film 22 is arranged on the expanded base film 21 to form the expanded fluororesin film 20, fluorine
  • the resin film 22b does not have a microporous structure, and its porosity is 0%. That is to say, the filling film 22 is a film layer formed by a single fluororesin, and the fluororesin film 22b is stacked on the expanded base film 21.
  • the fluororesin film 22b and the expanded base film 21 to form the expanded fluororesin film 20 after pressing.
  • the fluororesin film 22b is filled into the microporous structure of the expanded base film 21, thereby reducing the porosity of the expanded base film 21, that is, reducing the overall thickness of the copper clad laminate 100. Porosity, improving the solvent resistance performance of the copper clad laminate 100.
  • the filling film 22 is a fluororesin film 22b, and the fluororesin film 22b is pressed and arranged on the expanded base film 21 during the pressing process of the copper clad laminate 100, which can effectively improve the filling effect on the expanded base film 21. , to further ensure the solvent-proof performance of the copper clad laminate 100 .
  • the fluororesin film 22b is arranged between the copper foil layer 40 and the expanded base film 21, which helps to improve the bonding fastness between the copper foil layer 40 and the expanded base film 21, and reduces the surface deformation of the copper clad laminate 100, that is, further The dimensional deformation of the copper clad laminate 100 is reduced, and the dimensional stability of the copper clad laminate 100 is improved.
  • the fluororesin film 22b can be formed in various ways. After the fluororesin film 22b is formed, it is arranged on the expanded base film 21. For example, it can be formed by fluororesin emulsion.
  • the formed fluororesin film 22b may alternatively be a fluororesin film 22b formed by dry powder fluororesin, or may be a layer of fluororesin formed by other film-forming methods.
  • the combination of the expanded fluororesin film 20 and the first fluororesin emulsion film 30 is shown in Table 1 of Embodiment 1, wherein the thickness of the fluororesin film 22b may be 2-3 ⁇ m.
  • the performance of the obtained copper clad laminate 100 can also be the same as the performance of the copper clad laminate 100 in the first embodiment, that is, the Df value of the copper clad laminate 100 is 0.0005, the Dk value of the copper clad laminate 100 is 3, and the copper clad laminate The thickness of 100 is 6mil, and the void ratio of copper clad laminate 100 is 0%.
  • the filling film 22 is a fluororesin film 22b
  • the fluororesin film 22b is directly pressed on the expanded base film 21 to form the expanded fluororesin film 20
  • the middle layer is the first fluororesin emulsion film 30, and the middle layer
  • the above-mentioned expanded fluororesin film 20 is superimposed on the upper and lower sides of the upper and lower sides, and the obtained copper clad laminate 100 can reach Dk ⁇ 2.8, Df ⁇ 0.0008, Ds ⁇ 1000ppm, the CTE of the copper clad laminate 100 can reach 20-25ppm, and the void ratio of the copper clad laminate 100 0%. That is, the copper clad laminate 100 has a high Dk value, a low Df value, low expansion and shrinkage, and high solvent resistance.
  • FIG. 10 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 4 of the present application.
  • step S204 arranging filling films on the opposite sides of the puffed base film, specifically including:
  • a fluororesin film is provided, and the fluororesin film is disposed on opposite sides of the expanded base film.
  • the preparation method of the copper clad laminate includes:
  • S402 Obtain a first fluororesin emulsion, and immerse the substrate in the first fluororesin emulsion to form a first fluororesin emulsion film on opposite surfaces of the substrate.
  • S404 Provide a fluororesin film, and arrange the fluororesin film on two opposite sides of the expanded base film.
  • the expanded base film with fluororesin films on both sides is placed on the first fluororesin emulsion film.
  • S406 Provide a copper foil layer, and arrange the copper foil layer on the side of the expanded fluororesin film facing away from the substrate.
  • a copper clad laminate with Dk value, low Df value, and low expansion and shrinkage can be obtained. While improving its performance, it also has good dimensional stability, and further reduces the void ratio of the copper clad laminate, which can further ensure the copper clad laminate. solvent resistance properties.
  • the method is simple to operate and has good applicability.
  • FIG. 11 is a schematic cross-sectional view of a copper clad laminate provided in Embodiment 5 of the present application.
  • the copper clad laminate 100 further includes a fluororesin film 22b, and the fluororesin film 22b is arranged on the second fluororesin emulsion film 22a facing away from the expanded base film 21
  • the fluororesin film 22b is provided on one side, that is, between the copper foil layer 40 and the second fluororesin emulsion film 22a, and between the second fluororesin emulsion film 22a and the first fluororesin emulsion film 30, the fluororesin film 22b is provided.
  • the setting of the fluororesin film 22b helps to improve the bonding force between the copper foil layer 40 and the expanded fluororesin film 20, and between the first fluororesin emulsion film 30 and the second fluororesin emulsion film 22a, thereby improving the copper clad laminate 100.
  • the bonding fastness between the film layers further reduces the dimensional deformation of the copper clad laminate 100 , especially helps to reduce the surface deformation of the copper clad laminate 100 and improves the dimensional stability of the copper clad laminate 100 .
  • the second fluororesin emulsion film 22a can be formed on the opposite sides of the expanded base film 21 by dipping first, and then the fluororesin film 22b can be arranged on the side of the second fluororesin emulsion film 22a facing away from the expanded base film 21 .
  • the second fluororesin emulsion film 22a will be filled into the microporous structure of the expanded base film 21, reducing the porosity of the expanded base film 21, The overall porosity of the copper clad laminate 100 is reduced, thereby improving the solvent resistance of the copper clad laminate 100 .
  • the molding method of the fluororesin film 22b can be the same as that in the fourth embodiment.
  • the molding method of the second fluororesin emulsion film 22a can be the same as that in the third embodiment. Let me repeat.
  • the molding materials of the fluororesin film 22b, the second fluororesin emulsion film 22a, the first fluororesin emulsion film 30, and the expanded fluororesin film 20 may be the same or different, or any of them may be the same.
  • the combination of the expanded fluororesin film 20 and the first fluororesin emulsion film 30 is shown in Table 1 of Embodiment 1.
  • the thickness of the fluororesin film 22b may be 2-3 ⁇ m.
  • the performance of the obtained copper-clad laminate 100 may be the same as that of the copper-clad laminate 100 in Embodiment 1, that is, the Df value of the copper-clad laminate 100 is 0.0005.
  • the Dk value of the copper clad laminate 100 is 3, the thickness of the copper clad laminate 100 is 6mil, and the void ratio of the copper clad laminate 100 is 0%.
  • the filling film 22 the second fluororesin emulsion film 22a, the second fluororesin emulsion film 22a and the expanded base film 21 form the expanded fluororesin film 20, between the second fluororesin emulsion film 22a and the copper foil layer 40
  • the fluororesin film 22b is arranged between them, the middle layer of the copper clad laminate 100 is the substrate 10 provided with the first fluororesin emulsion film 30, and the upper and lower sides of the middle layer are respectively laminated with the fluororesin film 22b and the expanded fluororesin film 20, and the obtained copper clad laminate 100 can reach Dk ⁇ 2.8, Df ⁇ 0.0008, Ds ⁇ 1000ppm, the CTE of CCL 100 can reach 20-25ppm, and the porosity of CCL 100 is 0%. That is, the copper clad laminate 100 has a high Dk value, a low Df value, low expansion and shrinkage, and high solvent resistance.
  • FIG. 12 is a flowchart of a method for preparing a copper-clad laminate provided in Embodiment 5 of the present application.
  • the embodiment of the present application also provides a method for preparing a copper-clad laminate. Specifically, in the embodiment of the present application, after completing step S305: disposing the expanded fluororesin film on the side of the first fluororesin emulsion film facing away from the substrate, The method also includes:
  • a fluororesin film is provided, and the fluororesin film is disposed on the side of the second fluororesin emulsion film facing away from the expanded base film.
  • the first fluororesin emulsion film is formed on the opposite sides of the substrate by dipping
  • the second fluororesin emulsion film is formed on the opposite sides of the expanded base film
  • the second fluororesin emulsion film and the expanded base film jointly form an expanded fluorine resin.
  • the expanded fluororesin film is arranged on the first fluororesin emulsion film, and then the fluororesin film is stacked on the second fluororesin emulsion film of the expanded fluororesin film.
  • the preparation method of the copper clad laminate includes:
  • S502 Obtain a first fluororesin emulsion, and immerse the substrate in the first fluororesin emulsion to form a first fluororesin emulsion film on opposite surfaces of the substrate.
  • S504 Obtain a second fluororesin emulsion, and immerse the expanded base film in the second fluororesin emulsion to form a second fluororesin emulsion film on opposite sides of the expanded base film.
  • the second fluororesin emulsion film and the expanded base film jointly form the expanded fluororesin film.
  • the expanded base film with the second fluororesin emulsion film formed on both sides is arranged on the first fluororesin emulsion film.
  • S507 Provide a copper foil layer, and arrange the copper foil layer on the side of the expanded fluororesin film facing away from the substrate.
  • a copper clad laminate with a Dk value, a low Df value, and low expansion and contraction can be obtained. While improving its performance, it has better solvent resistance, and further reduces the dimensional deformation of the copper clad laminate, which can further improve Dimensional stability of copper clad laminates.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a An indirect connection through an intermediary may be an internal communication between two elements or an interaction relationship between two elements.
  • installation should be understood in a broad sense, for example, it can be a fixed connection or a An indirect connection through an intermediary may be an internal communication between two elements or an interaction relationship between two elements.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a An indirect connection through an intermediary may be an internal communication between two elements or an interaction relationship between two elements.

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Abstract

本申请实施例提供一种覆铜板及其制备方法，覆铜板包括基板，在基板相对的两面上设置有第一氟树脂乳液膜，在第一氟树脂乳液背向基板的一面上设置有膨化氟树脂膜，在膨化氟树脂膜背向基板的一面上叠加有铜箔层。使覆铜板的中间层为两面上设置有第一氟树脂乳液膜的基板，其Dk值和Df值较高，而中间层上下两侧为Dk值和Df值偏低、且尺寸稳定性较好的膨化氟树脂膜层，从而获得一种具有高Dk值、低Df值、低胀缩的覆铜板，在提升覆铜板性能的同时，提高了覆铜板的尺寸稳定性。

Description

一种覆铜板及其制备方法
本申请要求于2021年12月13日提交中国专利局、申请号为202111516805.8、申请名称为“一种覆铜板及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电路板技术领域，特别涉及一种覆铜板及其制备方法。
背景技术
随着电子工业的迅猛发展，在人们的日常生活中，可穿戴、便携只能设备等已经成为不可或缺的必需品，例如折叠手机、手表、平板电脑等电子设备。其中，柔性电路板(Flexible Printed Circuit Board；FPC)在电子设备中起到了关键的连接作用，而覆铜板(Copper Clad Laminate；CCL)作为柔性印刷电路板的基础板材，其在电子设备中有着广泛的应用。
目前，覆铜板多是以木浆纸或玻纤布等作为增强材料，在其两侧表面上形成氟树脂层，常见的可以为聚四氟乙烯树脂层。例如，覆铜板以玻纤布为基板，聚四氟乙烯树脂成膜后，在玻纤布相对的两侧面上叠合聚四氟乙烯树脂膜，并在聚四氟乙烯树脂膜背向玻纤布的一面上叠合铜箔，然后通过热压合的方式就形成覆铜板。
然而，氟树脂为热塑性材料，形成的覆铜板热膨胀系数较高，且介电常数值较低，介电损耗值较高，使覆铜板的插损较大而影响其性能。
发明内容
本申请提供一种覆铜板及其制备方法，解决了现有的覆铜板热胀系数较高且介电常数值较低，介电损耗值较高，使覆铜板插损较大而影响其性能的问题。
本申请的第一方面提供一种覆铜板，包括基板、膨化氟树脂膜、第一氟树脂乳液膜和铜箔层；
所述基板相对的两面上设置有所述第一氟树脂乳液膜；
所述第一氟树脂乳液膜背向所述基板的一面上设置有所述膨化氟树脂膜，所述膨化氟树脂膜具有多个微孔结构；
所述膨化氟树脂膜背向所述基板的一面上设置有所述铜箔层。这样覆铜板的中间层(以基板为中心，基板及其上设置的膜层共同可以作为中间层)为Dk值和Df值较高的膜层，而其中间层上下两侧采用的是Dk值和Df值偏低、且尺寸稳定性较好(Ds值偏低)的膜层。使覆铜板整体具有较高的Dk值和较低的Df值，有效的提升了覆铜板的性能。同时上下两侧两层高尺寸稳定性的膜层，可以有效的减小覆铜板的热胀缩，降低覆铜板的尺寸变形，提升了覆铜板的整体尺寸稳定性。所得到的覆铜板可达到Dk≥2.8，Df≤0.0008(在10GHz的频率测试条件下)，Ds≤1000ppm，覆铜板的CTE达到20-25ppm，在提升 覆铜板性能的同时，提高了覆铜板的尺寸稳定性。
在一种可能的实施方式中，所述膨化氟树脂膜包括膨化基膜和填充膜，所述微孔结构位于所述膨化基膜中；
所述填充膜分别位于所述膨化基膜相对的两面上，且所述填充膜填充所述微孔结构。这样填充膜就能够有效的降低膨化基膜的空隙率，从而降低覆铜板整体的空隙率，从而提升覆铜板的防溶剂性能，进一步保证覆铜板的性能。
在一种可能的实施方式中，所述填充膜为氟树脂膜，所述氟树脂膜设置在所述膨化基膜上。将氟树脂膜叠加设置在膨化基膜上，覆铜板成型时压合的过程中，使氟树脂膜与膨化基膜压合，氟树脂膜填充至膨化基膜的微孔结构中，操作简单方便，且对膨化基膜具有较好的填充作用，有助于进一步减小覆铜板的尺寸变形。
同时在铜箔层和膨化基膜之间设置有氟树脂膜，有助于提升铜箔层与膨化基膜之间的结合牢度，降低覆铜板的表面变形，进一步提升覆铜板的尺寸稳定性。
在一种可能的实施方式中，所述填充膜为第二氟树脂乳液膜。第二氟树脂乳液在膨化基膜上成膜形成第二氟树脂乳液膜的过程中，就会填充至膨化基膜的微孔结构中，结构简单，便于实现。
在一种可能的实施方式中，还包括氟树脂膜，所述氟树脂膜设置在所述第二氟树脂乳液膜背向所述膨化基膜的一面上。也即在铜箔层与第二氟树脂乳液膜之间，以及第二氟树脂乳液膜与第一氟树脂乳液膜之间设置有氟树脂膜，有助于提升铜箔层和膨化氟树脂膜之间、第一氟树脂乳液膜和第二氟树脂乳液膜之间的结合力，进而提升覆铜板中各膜层间的结合牢度，进一步降低覆铜板的尺寸变形，提升覆铜板的尺寸稳定性。
在一种可能的实施方式中，还包括增强件，所述增强件设置在所述第一氟树脂乳液膜内。增强件可以是陶瓷、二氧化钛等增强填料，有助于提升第一氟树脂乳液膜的强度，进而有助于提升覆铜板的尺寸稳定性。同时，通过增强件的比例等也可以调节第一氟树脂乳液膜的Dk值和Df值，以满足覆铜板的高Dk值、低Df值需求。
在一种可能的实施方式中，所述膨化基膜、所述填充膜、所述第一氟树脂乳液膜的成型材料至少包括：聚四氟乙烯、可熔性聚四氟乙烯或全氟乙烯丙烯共聚物。
在一种可能的实施方式中，所述基板至少包括玻璃纤维布。玻璃纤维布具有较低成本，且有助于提升覆铜板整体和表层的尺寸稳定性，进而有助于降低覆铜板的尺寸胀缩。
本申请的第二方面提供一种覆铜板的制备方法，所述方法包括：
提供基板；
获得第一氟树脂乳液，将所述基板浸入所述第一氟树脂乳液中，以在所述基板相对的两面上形成第一氟树脂乳液膜；
获得膨化氟树脂膜，所述膨化氟树脂膜具有多个微孔结构；
将所述膨化氟树脂膜设置在所述第一氟树脂乳液膜背向所述基板的一面上；
提供铜箔层，将所述铜箔层设置在所述膨化氟树脂膜背向所述基板的一面上；
压合，获得所述覆铜板。
通过上述方法即可得到覆铜板，该覆铜板具有高Dk值、低Df值、低胀缩，在提升覆铜板性能的同时，使覆铜板具有较好的尺寸稳定性，进而提升柔性电路板的电性能和稳定性。
在一种可能的实施方式中，所述膨化氟树脂膜包括膨化基膜和填充膜，所述微孔结构位于所述膨化基膜中，所述填充膜用于填充所述微孔结构；
所述获得所述膨化树脂膜包括：
获得膨化基膜；
在所述膨化基膜相对的两面上设置填充膜。
这样通过上述方法得到的覆铜板，填充膜填充至微孔结构内，能够降低覆铜板的空隙率，在提升覆铜板性能的同时，使其具有较好的尺寸稳定性和防溶剂性能。
在一种可能的实施方式中，所述填充膜为氟树脂膜。方法操作简单，在提升覆铜板性能的同时，还具有较好的尺寸稳定性，且进一步降低覆铜板的空隙率，可以进一步保证覆铜板的防溶剂性能。其该方法操作简单，具有很好的适用性。
在一种可能的实施方式中，所述填充膜为第二氟树脂乳液膜；
所述在所述膨化基膜相对的两面上设置填充膜包括：
获得第二氟树脂乳液，将所述膨化基膜浸入所述第二氟树脂乳液中，以在所述膨化基膜相对的两面上形成第二氟树脂乳液膜。方法简单，便于实现，且在提升覆铜板性能的同时，使其具有较好尺寸稳定性和防溶剂性能。
在一种可能的实施方式中，所述覆铜板还包括氟树脂膜，所述将所述膨化氟树脂膜设置在所述第一氟树脂乳液膜背向所述基板的一面上后，所述方法还包括：
提供氟树脂膜，将所述氟树脂膜设置在所述第二氟树脂乳液膜背向所述膨化基膜的一面上。
这样通过上述步骤方法就在第二氟树脂乳液膜和铜箔层、以及第二氟树脂乳液膜和第一氟树脂乳液膜之间设置氟树脂膜，氟树脂膜能够提升各膜层之间的结合牢度，进一步降低覆铜板的尺寸变形。
在一种可能的实施方式中，所述获得第一氟树脂乳液之后还包括：
在所述第一氟树脂乳液中添加增强件。
在一种可能的实施方式中，所述提供铜箔层之后还包括：
对所述铜箔层表面进行粗化处理；
对经粗化处理后的所述铜箔层的表面进行氟化处理。首先对铜箔层进行粗化处理，然后进行氟化处理，可以提升铜箔层表面的含氟量，而使铜箔层表面具有一定的氟，能够提升铜箔层与膨化氟树脂膜之间的结合强度，有助于提升覆铜板整体的尺寸稳定性。
本申请的第三方面还提供一种柔性电路板，至少包括线路结构和上述任一所述的覆铜板，所述线路结构设置在所述覆铜板上。
通过包括具有高Dk值、低Df值、低胀缩的覆铜板，能够有效的提升柔性电路板的电性能和稳定性能。
本申请的第四方面还提供一种电子设备，至少包括壳体和上述的柔性电路板，所述柔性电路板设置在所述壳体内。
附图说明
图1为本申请实施例提供的一种覆铜板的结构示意图；
图2为现有技术中的一种覆铜板的剖面示意图；
图3为图1中覆铜板沿A-A线的剖面结构示意图；
图4为本申请实施例一提供的一种覆铜板的制备方法流程图；
图5为本申请实施例二提供的一种覆铜板的剖面结构示意图；
图6为本申请实施例二提供的一种覆铜板的制备方法流程图；
图7为本申请实施例三提供的一种覆铜板的剖面结构示意图；
图8为本申请实施例三提供的一种覆铜板的制备方法流程图；
图9为本申请实施例四提供的一种覆铜板的剖面结构示意图；
图10为本申请实施例四提供的一种覆铜板的制备方法流程图；
图11为本申请实施例五提供的一种覆铜板的剖面示意图；
图12为本申请实施例五提供的一种覆铜板的制备方法流程图。
附图标记说明：
100-覆铜板；    10-基板；              20-膨化氟树脂膜；
21-膨化基膜；   22-填充膜；            22a-第二氟树脂乳液膜；
22b-氟树脂膜；  30-第一氟树脂乳液膜；  40-铜箔层。
具体实施方式
本申请的实施方式部分使用的术语仅用于对本申请的具体实施例进行解释，而非旨在限定本申请，下面将结合附图对本申请实施例的实施方式进行详细描述。
图1为本申请实施例提供的一种覆铜板的结构示意图。
本申请实施例中，覆铜板(Copper Clad Laminate；CCL)可以为印制电路板(Printed Circuit Board；PCB)的基本板材，也叫基材。
在本申请实施例中，以图1中覆铜板100为柔性电路板(Flexible Printed Circuit Board；FPCB)的基材为例，在覆铜板100上可以设置有线路结构以形成柔性电路板。
其中，该柔性电路板可以应用于电子设备的柔性架构产品中，例如板内跳线、板对板连接以及封装出柔性板等柔性连接场景中。
电子设备可以包括但不限于为手机、平板电脑、笔记本电脑、超级移动个人计算机(ultra-mobile personal computer，UMPC)、手持计算机、触控电视、对讲机、上网本、POS机、个人数字助理(personal digital assistant，PDA)、可穿戴设备、虚拟现实设备等固定终端或移动终端。
为保证电子设备的性能，通常对覆铜板形成的柔性电路板的电性能要求会较高，要求其具有较低的插损值，例如保持在0.4dB/inch以内。而柔性电路板的电性能与覆铜板的性能有很大的关联，因此，在获得覆铜板之后会对其性能进行检测衡量，其中，判断的标准主要包括覆铜板的介电常数(Dielectronic Constant；Dk)和覆铜板的介电损耗(Dielectronic Fonstant；Df)。
具体的，介电常数Dk，是指介质在外加电场时会产生感应电荷而削弱电场，介质中的电场减小与原外加电场(真空中)的比值即为相对介电常数，Dk值为衡量电介质极化程度的宏观物理量。Dk值越大，表面束缚电荷的能力越强，电荷越不容易极化，极化电场越弱，材料的绝缘性能越好。
介电损耗Df，是指绝缘材料或电介质在交变电场中，由于介质电导和介质极化的滞后 效应，使电介质内流过的电流相量和电压相量之间产生一定的相位差，即形成一定的相角，此相角的正切值即介电损耗Df，Df值越高，介质电导和介质极化滞后效应越明显，电能损耗或信号损失越多。
另外，需要说明的是，在本申请实施例中，尺寸稳定性(Dimensional Stability Properties；Ds)是指材料在受机械力、热或其他外界条件作用下，其外形尺寸不发生变化的性能。Ds值越小，表明板材的尺寸稳定性越好，其尺寸胀缩越小。
图2为现有技术中的一种覆铜板的剖面示意图。
目前，覆铜板多是以木浆纸或玻纤布等作为增强基板，在基板两侧表面上设置树脂层，然后覆以铜箔，经热压后形成。其中，覆铜板中较为常用的树脂层材料为氟树脂，如聚四氟乙烯树脂，例如，参见图2所示，相关技术中提出的一种聚四氟乙烯覆铜板，通过将聚四氟乙烯树脂膜2直接设置在玻璃纤维布1上，并在其上覆以铜箔层3，通过热压合得到。
由于聚四氟乙烯材料为热塑性材料，覆铜板的热膨胀系数(Coefficient of Thermal Expansion；CTE)较大，覆铜板会存在热胀缩的问题，影响其尺寸稳定性，因此，热胀缩、介电常数以及介电损耗成为判断氟树脂型覆铜板性能的主要指标。而上述通过热压合直接将聚四氟乙烯树脂压合至玻璃纤维布上得到的覆铜板，其尺寸稳定性较差(Ds值较高)，覆铜板的尺寸胀缩较为严重，且电性能调控范围较小，Dk值较低，而Df值较高，使覆铜板的插损较大，覆铜板的整体性能较差。
基于此，本申请实施例提供一种覆铜板，尺寸胀缩小(热膨胀系数CTE在20-25ppm之间，Ds≤1500ppm)，且其Dk值较高(Dk≥3)，Df值较低(Df≤0.0008)，有效的提高了覆铜板的性能，有助于提升柔性电路板的电性能。
以下结合具体实施例以及附图对本申请实施例提供的覆铜板及其制备方法进行详细的说明。
实施例一
图3为图1中覆铜板沿A-A线的剖面结构示意图。
参见图3所示，本申请实施例中，覆铜板100包括基板10，基板10至少包括玻璃纤维布，例如，基板10可以是规格为1080的玻璃纤维布，其公称厚度可以为0.053mm，单位面积质量可以为46.8g/m 2。该玻璃纤维布能够有效的提升覆铜板100整体和表层的尺寸稳定性，进而有助于降低覆铜板100的尺寸胀缩。
当然，在一些示例中，基板10也可以是有机纤维布、氟树脂膜层、聚酰亚胺膜层等其他增强材料形成的板材。
覆铜板100还包括有第一氟树脂乳液膜30，第一氟树脂乳液膜30设置在基板10相对的两面上，具体的，该第一氟树脂乳液膜30可以是将基板10浸入第一氟树脂乳液中，从而在基板10相对的两侧表面上形成的膜层。也就是说，通过浸渍的方式，使第一氟树脂乳液在基板10的表面上成膜，从而在基板10的表面上形成第一氟树脂乳液膜30。
由氟树脂乳液在基板10表面成膜形成的氟树脂乳液膜，具有较高的Dk值(例如，Dk＝3.7)和Df值(例如，Df＝0.0008)，也即第一氟树脂乳液膜30具有较高的Dk值和Df值。
其中，第一氟树脂乳液膜30的成型材料可以为聚四氟乙烯(Polytetrafluoroethylene； PTFE)，或者，在一些示例中，第一氟树脂乳液膜30的成型材料可以是其他类型的含氟树脂，例如，可以是可熔性聚四氟乙烯(Polytetrafluoro ethylene；PFA)或全氟乙烯丙烯共聚物(Fluorinated ethylene propylene；FEP)等。
第一氟树脂乳液膜内可以设置有增强件，增强件可以是陶瓷、二氧化钛、锶酸钡等增强填料。具体的，可以在第一氟树脂乳液中加入增强件，第一氟树脂乳液在基板10两侧表面上成膜时，增强件分布在第一氟树脂乳液膜30中，这样有助于提升第一氟树脂乳液膜30的强度，进而有助于提升覆铜板100的尺寸稳定性。同时，通过增强件的比例等也可以调节第一氟树脂乳液膜30的Dk值和Df值，以满足覆铜板100的高Dk值、低Df值需求。
覆铜板100还包括有膨化氟树脂膜20和铜箔层40，膨化氟树脂膜20设置在第一氟树脂乳液膜30背向基板10的一面上。其中，膨化氟树脂膜20是指膜层上形成有多个微孔结构的氟树脂膜，具有预设的空隙率。其多为通过干粉氟树脂加工的方式得到，例如，将干粉氟树脂经过石蜡，全氟辛酸铵等溶剂处理后，经过压延机单/双轴辊压拉伸成一定的空隙率，从而获得膨化氟树脂膜层。
膨化氟树脂膜层具有相对较低的Dk值(例如，其Dk＝2.6)和Df值(例如，其Df＝0.0003)。且由于膨化氟树脂膜20具有多个微孔结构，其尺寸稳定性较好，其Ds值约等于1500ppm。
在基板10相对的两面上均设置有第一氟树脂乳液膜30，参见图3所示，也即基板上设置有两层第一氟树脂乳液膜30，可以在两层第一氟树脂乳液膜30背向基板的一面上分别设置有膨化氟树脂膜20，也即覆铜板100包括有两层膨化氟树脂膜20。
其中，膨化氟树脂膜20的Dk值和Df值还可以通过干粉氟树脂的成膜工艺来调整。同时，也可以在膨化氟树脂膜20成膜时，加入填料(如二氧化硅、二氧化钛等无机氧化物填料)，也就是说在干粉氟树脂中加入填料，通过调节填料和干粉氟树脂的比例以及成膜工艺，可以实现对膨化氟树脂膜20的空隙率的调整控制，进而调整覆铜板100整体的空隙率，可以保证覆铜板100的空隙率为0％，从而提升覆铜板100的防溶剂性能，保证覆铜板100的性能。
需要说明的是，在本实施例中，膨化氟树脂膜20为单一的氟树脂成膜形成的膜层，并对形成的膜层进行拉伸等膨化以形成微孔结构，如膨化氟树脂膜20为干粉氟树脂直接加工形成的膜层。当然，在一些示例中，膨化氟树脂膜20可以是具有微孔结构的单一氟树脂膜层与其他膜层(如填充膜等)的复合膜。
膨化氟树脂膜20的成型材料可以为聚四氟乙烯，或者，也可以是其他类型的含氟树脂，如可熔性聚四氟乙烯或全氟乙烯丙烯共聚物等。膨化氟树脂膜20的成型材料可以与第一氟树脂乳液膜30的成型材料相同，如膨化氟树脂膜20和第一氟树脂乳液膜30均可以是聚四氟乙烯成膜，或者，两者的成型材料也可以不同。
铜箔层40设置在膨化氟树脂膜20背向基板10的一面上，具体的，在两层膨化氟树脂膜20背向基板10的一面上分别叠加设置铜箔层40，形成覆铜板100。
也就是说，本申请实施例提供的一种覆铜板100，其中间层(以基板10为中心，基板10及其上设置的膜层可以作为中间层)为Dk值和Df值较高的膜层，而其中间层上下两侧采用的是Dk值和Df值偏低、且尺寸稳定性较好(Ds值偏低)的膜层。使覆铜板100整体具有较高的Dk值和较低的Df值，有效的提升了覆铜板100的性能。同时上下两侧两 层高尺寸稳定性的膜层，可以有效的减小覆铜板100的热胀缩，降低覆铜板100的尺寸变形，提升了覆铜板100的整体尺寸稳定性。
下表1中示出了一种示例中覆铜板所包括的膨化氟树脂膜以及第一氟树脂乳液膜的组合方式，下表2示出了一种示例中所得到的覆铜板的性能。其中，膨化氟树脂膜20的组合比例是指，位于基板10上下两侧的两层膨化氟树脂膜20的膜厚度和，例如，单层膨化氟树脂膜20的厚度为25μm，则组合比例为50μm。相应的，第一氟树脂乳液膜30的组合比例是指，位于基板10上下两侧的两层第一氟树脂乳液膜30的膜厚度和。
表1为本申请实施例一提供的一种覆铜板中膜层的性能表
组合 Df Dk 组合比例(μm) 体积比
膨化氟树脂膜 0.0002 2.2 50 50.00％
第一氟树脂乳液膜 0.0008 3.8 50 50.00％
表2为本申请实施例一提供的一种覆铜板的性能表
  Df Dk 厚度
覆铜板 0.0005 3 6mil
结合表1和表2可知，通过浸渍在基板10表面形成高Dk值和Df值的第一氟树脂乳液膜30作为覆铜板100的中间层，在中间层的上下两侧设置低Dk值和Df值，且尺寸稳定性较好的膨化氟树脂膜20，使覆铜板100可达到Dk≥2.8，Df≤0.0008(在10GHz的频率测试条件下)，Ds≤1000ppm，覆铜板100的CTE达到20-25ppm，形成一种具有高Dk值、低Df值、低胀缩的覆铜板100，有效提升覆铜板100的性能，并提高了覆铜板100的尺寸稳定性。
图4为本申请实施例一提供的一种覆铜板的制备方法流程图。
本申请实施例还提供一种覆铜板的制备方法，具体的，该方法包括以下步骤：
S101：提供基板。
S102：获得第一氟树脂乳液，将基板浸入第一氟树脂乳液中，以在基板相对的两面上形成第一氟树脂乳液膜。
其中，获得第一氟树脂乳液后，可以按照一定的比例，在第一氟树脂乳液中加入添加剂、增强填料等，然后经过高速搅拌机搅拌，并经过匀质处理后备用。其中，添加剂可以是乙醚、甲醛等有机溶剂。
基板浸入第一氟树脂乳液中，具体的，可以是将备用的第一氟树脂乳液加入上胶机的浸胶槽中，使基板经过浸胶槽，实现基板在第一氟树脂乳液中的浸渍。
其中，在基板的浸渍过程中，可以通过刮胶棍来控制第一氟树脂乳液在基板上浸渍的量，进而控制在基板表面形成的第一氟树脂乳液膜的厚度。
在浸渍完成后，可以将浸渍有第一氟树脂乳液的基板进行烘干，例如，将基板放入烘箱内烘干，以去除添加剂，从而在基板表面上形成第一氟树脂乳液膜。
S103：获得膨化氟树脂膜。
其中，膨化氟树脂膜上具有多个微孔结构，具体的，膨化氟树脂膜成膜方式可以为：将干粉氟树脂经过溶剂处理，然后通过压延机的单/双轴辊压拉伸成膜，可以通过调节其成膜工艺来控制膨化氟树脂膜的空隙率，也即调节膨化氟树脂膜的Dk值和Df值。
其中，该溶剂可以是石蜡，全氟辛酸铵等。
S104：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上。
也即，将膨化氟树脂膜叠加至第一氟树脂乳液膜上。其中，每一层第一氟树脂乳液膜背向基板的一面上均设置有膨化氟树脂膜。
S105：提供铜箔层，将铜箔层设置在膨化氟树脂膜背向基板的一面上。
也即在膨化氟树脂膜上叠加铜箔层。其中，在每一层膨化氟树脂膜背向基板的一面上均叠加设置铜箔层。
其中，在提供铜箔层后，该方法还可以包括：
对铜箔层表面进行粗化处理；
对经粗化处理后的铜箔层的表面进行氟化处理。
首先对铜箔层进行粗化处理，然后进行氟化处理，可以提升铜箔层表面的含氟量，而使铜箔层表面具有一定的氟，能够提升铜箔层与膨化氟树脂膜之间的结合强度，有助于提升覆铜板整体的尺寸稳定性。
S106：压合，获得覆铜板。
其中，压合可以通过真空压机实现，也即将铜箔层、膨化氟树脂膜、第一氟树脂乳液膜和基板按照上述步骤叠加后，通过真空压机，在真空、高压、高温调节下自动压合，然后降温拆板就能够获得覆铜板。
通过上述步骤就能够得到具有Dk值、低Df值、低胀缩的覆铜板，在提升覆铜板性能的同时使其具有较高的尺寸稳定性，进而提升柔性电路板的电性能和稳定性。
实施例二
图5为本申请实施例二提供的一种覆铜板的剖面结构示意图。
参见图5所示，与实施例一不同的是，在本申请实施例中，膨化氟树脂膜20包括膨化基膜21和填充膜22，也就是说，膨化氟树脂膜20为膨化基膜21与填充膜22的复合膜层。其中，膨化基膜21可以与实施例一中的膨化氟树脂膜20相同，为具有微孔结构的单一氟树脂膜层，具有预设的空隙率。膨化基膜21可以为通过干粉氟树脂加工成膜获得的，膨化氟树基膜具有相对较低的Dk值和Df值，且具有较好的尺寸稳定性。
填充膜22可以为任意含氟的膜层，微孔结构位于膨化基膜21中，填充膜22分别位于膨化基膜21相对的两面上，且填充膜22填充微孔结构，这样填充膜22就能够有效的降低膨化基膜21的空隙率，从而降低覆铜板100整体的空隙率，从而提升覆铜板100的防溶剂性能，进一步提高覆铜板100的性能。
也就是说，本申请实施例提供的一种覆铜板100，其中间层仍为两面设置有第一氟树脂乳液膜30的基板10，具有较高的Dk值和Df值，在中间层上下两侧设置具有填充膜22的膨化基膜21，保持有较低的Dk值和Df值、以及较好的尺寸稳定性，同时还具有较低的空隙率。使覆铜板整体具有高Dk值、低Df值、以及低胀缩性能，在提升覆铜板100性能的同时，减小了覆铜板100的尺寸变形，并提升了覆铜板100的防溶剂性能。
其中，填充膜22的成型材料可以为聚四氟乙烯，或者，在一些示例中，填充膜22的成型材料也可以是其他类型的含氟树脂，例如，填充膜22可以为可熔性聚四氟乙烯或全氟乙烯丙烯共聚物。填充膜22的成型材料可以与第一氟树脂乳液膜30和膨化基膜21的 成型材料相同，或者，三者的成型材料也可以不同。
其中，膨化氟树脂膜20与第一氟树脂乳液膜30的组合方式见实施例一的表1，本申请实施例中，所得到的的覆铜板100的性能可以达到与实施例一中覆铜板100的性能相同，即覆铜板100的Df值为0.0005，覆铜板100的Dk值为3，覆铜板100的厚度为6mil，而覆铜板100的空隙率为0％。
也就是说，使膨化氟树脂膜20包括膨化基膜21和填充膜22，通过浸渍在基板10表面形成高Dk值和Df值的第一氟树脂乳液膜30作为覆铜板100的中间层，在中间层的上下两侧叠加设置有填充膜22的膨化基膜21，中间层上下两侧膜层仍具有低的Dk值和Df值，且具有较好的尺寸稳定性，使覆铜板100可达到Dk≥2.8，Df≤0.0008，Ds≤1000ppm，覆铜板100的CTE达到20-25ppm，且覆铜板100的空隙率为0％。也即该覆铜板100具有高Dk值、低Df值、低胀缩以及高防溶剂性能。
图6为本申请实施例二提供的一种覆铜板的制备方法流程图。
本申请实施例还提供一种覆铜板的制备方法，具体的，在本申请实施例中，步骤S103：获得膨化树脂膜，具体包括：
获得膨化基膜；
在膨化基膜相对的两面上设置填充膜。
这样在压合形成覆铜板时，填充膜会与膨化基膜压合，填充膜填充膨化基膜的微孔结构，从而形成膨化氟树脂膜。
参见图6所示，具体的，覆铜板的制备方法包括：
S201：提供基板。
S202：获得第一氟树脂乳液，将基板浸入第一氟树脂乳液中，以在基板相对的两面上形成第一氟树脂乳液膜。
S203：获得膨化基膜。
其中，膨化基膜的成型方式可以与实施例一中膨化氟树脂膜的成型方式相同，具体参见实施例一，在本实施例中不再赘述。
S204：在膨化基膜相对的两面上设置填充膜。
其中，填充膜可以是先成膜后将膜设置于膨化基膜相对的两面上，或者，填充膜也可以是将膨化基膜浸入乳液中，通过浸渍的方式在填充膜表面上形成填充膜。
S205：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上。
也即将两面设置有填充膜的膨化基膜设置在第一氟树脂乳液膜上。
S206：提供铜箔层，将铜箔层设置在膨化氟树脂膜背向基板的一面上。
S207：压合，获得覆铜板。
通过上述步骤能够得到具有Dk值、低Df值、低胀缩的覆铜板，在提升其性能的同时，使其具有较好的防溶剂性能以及尺寸稳定性。
实施例三
图7为本申请实施例三提供的一种覆铜板的剖面结构示意图。
参见图7所示，在实施例二的基础上，在本申请实施例中，填充膜22为第二氟树脂乳液膜22a，第二氟树脂乳液膜22a可以为膨化基膜21浸入第二氟树脂乳液中，从而在膨 化基膜21表面上形成的膜层。也就是说，可以通过浸渍的方式，使第二氟树脂乳液在膨化基膜21的表面上成膜，从而在膨化基膜21上形成第二氟树脂乳液膜22a。
在浸渍、成膜、以及覆铜板100制备的压合过程中，第二氟树脂乳液膜22a会填充至膨化基膜21的微孔结构中，从而减小膨化基膜21的空隙率，也即降低覆铜板100整体的空隙率，提升覆铜板100的防溶剂性能。
其中，第二氟树脂乳液膜22a的成型材料以及成型方式可以与第一氟树脂乳液膜30相同，例如，可以在第二氟树脂乳液中添加增强件，以在第二氟树脂乳液成膜时，使增强件分布在第二氟树脂乳液膜22a中，进一步提升膨化氟树脂膜20的尺寸稳定性。相应的，第二氟树脂乳液中也可以加入添加剂。
当然，在一些示例中，第二氟树脂乳液中可以不加入增强件，第二氟树脂乳液中也可以减小加入的添加剂量。
其中，膨化氟树脂膜20与第一氟树脂乳液膜30的组合方式见实施例一表1。本申请实施例中，所得到的的覆铜板100的性能也能够达到与实施例一中覆铜板100的性能相同，即覆铜板100的Df值为0.0005，覆铜板100的Dk值为3，覆铜板100的厚度为6mil，而覆铜板100的空隙率为0％。
也就是说，使填充膜22为第二氟树脂乳液膜22a，并通过浸渍方式在膨化基膜21表面形成第二氟树脂乳液膜22a以组成膨化氟树脂膜20，使其中间层为第一氟树脂乳液膜30，中间层的上下两侧叠加上述的膨化氟树脂膜20，得到的覆铜板100可达到Dk≥2.8，Df≤0.0008，Ds≤1000ppm，覆铜板100的CTE达到20-25ppm，且覆铜板100的空隙率为0％。也即覆铜板100具有高Dk值、低Df值、低胀缩以及高防溶剂性能。
图8为本申请实施例三提供的一种覆铜板的制备方法流程图。
本申请实施例还提供一种覆铜板的制备方法，具体的，在本申请实施例中，步骤S204：在膨化基膜相对的两面上设置填充膜，具体包括：
获得第二氟树脂乳液，将膨化基膜浸入第二氟树脂乳液中，以在膨化基膜相对的两面上形成第二氟树脂乳液膜。
其中，在获得第二氟树脂乳液后，可在第一氟树脂乳液中加入添加剂、增强件等，具体的实施方式参见实施例一，在本实施例中不再赘述。
在浸渍时，可以将第二氟树脂乳液加入上胶机的浸胶槽中，使膨化基膜经过浸胶槽，并通过刮胶棍来控制第二氟树脂乳液在膨化基板上浸渍的量，进而控制在膨化基膜表面形成的第二氟树脂乳液膜的厚度。在浸渍完成后，可以将浸渍有第二氟树脂乳液的膨化进行烘干，从而在膨化基膜表面上形成第二氟树脂乳液膜。
参见图8所示，具体的，覆铜板的制备方法包括：
S301：提供基板。
S302：获得第一氟树脂乳液，将基板浸入第一氟树脂乳液中，以在基板相对的两面上形成第一氟树脂乳液膜。
S303：获得膨化基膜。
S304：获得第二氟树脂乳液，将膨化基膜浸入第二氟树脂乳液中，以在膨化基膜相对的两面上形成第二氟树脂乳液膜。
这样膨化基膜和设置在膨化基膜相对两面上的第二氟树脂乳液膜就共同形成了膨化 氟树脂膜。
S305：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上。
也即将两面形成有第二氟树脂乳液膜的膨化基膜设置在第一氟树脂乳液膜上。
S306：提供铜箔层，将铜箔层设置在膨化氟树脂膜背向基板的一面上。
S307：压合，获得覆铜板。
通过上述步骤能够得到具有Dk值、低Df值、低胀缩的覆铜板，在提升覆铜板性能的同时，使其具有较高的尺寸稳定性和防溶剂性能，进而提升柔性电路板的电性能和稳定性，且方法简单便于实现。
实施例四
图9为本申请实施例四提供的一种覆铜板的剖面结构示意图。
参见图9所示，在实施例二的基础上，在本申请实施例中，填充膜22为氟树脂膜22b，填充膜22设置在膨化基膜21上，以形成膨化氟树脂膜20，氟树脂膜22b不具有微孔结构，其空隙率为0％。也就是说，填充膜22为单一氟树脂成型的膜层，将氟树脂膜22b叠加设置在膨化基膜21上，覆铜板100成型时压合的过程中，使氟树脂膜22b与膨化基膜21压合后形成膨化氟树脂膜20。
氟树脂膜22b与膨化基膜21压合设置的过程中，氟树脂膜22b填充至膨化基膜21的微孔结构内，从而减小膨化基膜21的空隙率，也即降低覆铜板100整体的空隙率，提升覆铜板100的防溶剂性能。
而且，填充膜22为氟树脂膜22b，在覆铜板100成型时压合的过程中，使氟树脂膜22b压合设置在膨化基膜21上，能够有效的提升对膨化基膜21的填充作用，进一步保证覆铜板100的防溶剂性能。同时在铜箔层40和膨化基膜21之间设置氟树脂膜22b，有助于提升铜箔层40与膨化基膜21之间的结合牢度，降低覆铜板100的表面变形，也即进一步减小覆铜板100的尺寸变形，提升覆铜板100的尺寸稳定性。
应当理解的是，氟树脂膜22b的成膜方式可以是多种，在氟树脂成膜形成氟树脂膜22b后，将其设置在膨化基膜21上，例如，可以是通过氟树脂乳液成膜形成的氟树脂膜22b，或者，也可以是通过干粉氟树脂成膜后形成的氟树脂膜22b，或者也可以是氟树脂经其他成膜方式形成的膜层。
其中，膨化氟树脂膜20与第一氟树脂乳液膜30的组合方式见实施例一表1，其中，氟树脂膜22b的厚度可以为2-3μm。本申请实施例中，所得到的的覆铜板100的性能也能够与实施例一中覆铜板100的性能相同，即覆铜板100的Df值为0.0005，覆铜板100的Dk值为3，覆铜板100的厚度为6mil，而覆铜板100的空隙率为0％。
也就是说，使填充膜22为氟树脂膜22b，将氟树脂膜22b直接压设在膨化基膜21上形成膨化氟树脂膜20，使其中间层为第一氟树脂乳液膜30，中间层的上下两侧叠加上述的膨化氟树脂膜20，得到的覆铜板100可达到Dk≥2.8，Df≤0.0008，Ds≤1000ppm，覆铜板100的CTE达到20-25ppm，且覆铜板100的空隙率为0％。也即覆铜板100具有高Dk值、低Df值、低胀缩以及高防溶剂性能。
图10为本申请实施例四提供的一种覆铜板的制备方法流程图。
本申请实施例还提供一种覆铜板的制备方法，具体的，在本申请实施例中，步骤S204：在膨化基膜相对的两面上设置填充膜，具体包括：
提供氟树脂膜，将氟树脂膜设置在膨化基膜相对的两面上。
参见图10所示，具体的，覆铜板的制备方法包括：
S401：提供基板。
S402：获得第一氟树脂乳液，将基板浸入第一氟树脂乳液中，以在基板相对的两面上形成第一氟树脂乳液膜。
S403：获得膨化基膜。
S404：提供氟树脂膜，将氟树脂膜设置在膨化基膜相对的两面上。
S405：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上。
也即将两面上分别设置有氟树脂膜的膨化基膜设置在第一氟树脂乳液膜上。
S406：提供铜箔层，将铜箔层设置在膨化氟树脂膜背向基板的一面上。
S407：压合，获得覆铜板。
通过上述步骤能够得到具有Dk值、低Df值、低胀缩的覆铜板，在提升其性能的同时，还具有较好的尺寸稳定性，且进一步降低覆铜板的空隙率，可以进一步保证覆铜板的防溶剂性能。其该方法操作简单，具有很好的适用性。
实施例五
图11为本申请实施例五提供的一种覆铜板的剖面示意图。
参见图11所示，在实施例二的基础上，在本申请实施例中，覆铜板100还包括氟树脂膜22b，氟树脂膜22b设置在第二氟树脂乳液膜22a背向膨化基膜21的一面上，也就是说，在铜箔层40与第二氟树脂乳液膜22a之间，以及第二氟树脂乳液膜22a与第一氟树脂乳液膜30之间设置有氟树脂膜22b。氟树脂膜22b的设置有助于提升铜箔层40和膨化氟树脂膜20之间、第一氟树脂乳液膜30和第二氟树脂乳液膜22a之间的结合力，进而提升覆铜板100中各膜层间的结合牢度，进一步降低覆铜板100的尺寸变形，尤其有助于减小覆铜板100表面变形，提升覆铜板100的尺寸稳定性。
其中，可以首先通过浸渍的方式，在膨化基膜21相对的两面上形成第二氟树脂乳液膜22a，然后在第二氟树脂乳液膜22a背向膨化基膜21的一面上设置氟树脂膜22b。
同样的，在浸渍、成膜、以及覆铜板100制备的压合过程中，第二氟树脂乳液膜22a会填充至膨化基膜21的微孔结构中，减小膨化基膜21的空隙率，降低覆铜板100整体的空隙率，从而提升覆铜板100的防溶剂性能。
其中，氟树脂膜22b的成型方式可以与实施例四中的成型方式相同，相应的，第二氟树脂乳液膜22a的成型方式可以与实施例三中的成型方式相同，在本实施例中不再赘述。氟树脂膜22b与第二氟树脂乳液膜22a、第一氟树脂乳液膜30和膨化氟树脂膜20的成型材质可以相同，或者也可以不相同，或者也可以是其中任几个相同。
膨化氟树脂膜20与第一氟树脂乳液膜30的组合方式见实施例一表1。氟树脂膜22b的厚度可以为2-3μm，本申请实施例中，所得到的的覆铜板100的性能可以与实施例一中覆铜板100的性能相同，即覆铜板100的Df值为0.0005，覆铜板100的Dk值为3，覆铜板100的厚度为6mil，而覆铜板100的空隙率为0％。
也就是说，使填充膜22为第二氟树脂乳液膜22a，第二氟树脂乳液膜22a和膨化基膜21组成膨化氟树脂膜20，在第二氟树脂乳液膜22a与铜箔层40之间设置氟树脂膜22b， 覆铜板100的中间层为设置有第一氟树脂乳液膜30的基板10，中间层的上下两侧分别叠加氟树脂膜22b和膨化氟树脂膜20，得到的覆铜板100可达到Dk≥2.8，Df≤0.0008，Ds≤1000ppm，覆铜板100的CTE达到20-25ppm，且覆铜板100的空隙率为0％。也即覆铜板100具有高Dk值、低Df值、低胀缩以及高防溶剂性能。
图12为本申请实施例五提供的一种覆铜板的制备方法流程图。
本申请实施例还提供一种覆铜板的制备方法，具体的，在本申请实施例中，在完成步骤S305：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上后，该方法还包括：
提供氟树脂膜，将氟树脂膜设置在第二氟树脂乳液膜背向膨化基膜的一面上。
也就是说，分别通过浸渍的方式，在基板相对两面形成第一氟树脂乳液膜，在膨化基膜相对两面形成第二氟树脂乳液膜，第二氟树脂乳液膜和膨化基膜共同形成膨化氟树脂膜，将膨化氟树脂膜设置在第一氟树脂乳液膜上，再将氟树脂膜叠设在膨化氟树脂膜的第二氟树脂乳液膜上。
参见图12所示，具体的，覆铜板的制备方法包括：
S501：提供基板。
S502：获得第一氟树脂乳液，将基板浸入第一氟树脂乳液中，以在基板相对的两面上形成第一氟树脂乳液膜。
S503：获得膨化基膜。
S504：获得第二氟树脂乳液，将膨化基膜浸入第二氟树脂乳液中，以在膨化基膜相对的两面上形成第二氟树脂乳液膜。
其中，第二氟树脂乳液膜和膨化基膜共同形成膨化氟树脂膜。
S505：将膨化氟树脂膜设置在第一氟树脂乳液膜背向基板的一面上。
也即将两面形成有第二氟树脂乳液膜的膨化基膜设置在第一氟树脂乳液膜上。
S506：提供氟树脂膜，将氟树脂膜设置在第二氟树脂乳液膜背向膨化基膜的一面上。
S507：提供铜箔层，将铜箔层设置在膨化氟树脂膜背向基板的一面上。
S508：压合，获得覆铜板。
通过上述步骤能够得到具有Dk值、低Df值、低胀缩的覆铜板，在提升其性能的同时，使其具有较好的防溶剂性能，且进一步降低了覆铜板的尺寸变形，可以进一步提升覆铜板的尺寸稳定性。
在本申请实施例的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应作广义理解，例如，可以是固定连接，也可以是通过中间媒介间接相连，可以是两个元件内部的连通或者两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。
最后应说明的是：以上各实施例仅用以说明本申请实施例的技术方案，而非对其限制；尽管参照前述各实施例对本申请实施例进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请实施例各实施例技术方案的范围。

Claims (17)

  1. 一种覆铜板，其特征在于，包括基板、膨化氟树脂膜、第一氟树脂乳液膜和铜箔层；
    所述基板相对的两面上设置有所述第一氟树脂乳液膜；
    所述第一氟树脂乳液膜背向所述基板的一面上设置有所述膨化氟树脂膜，所述膨化氟树脂膜具有多个微孔结构；
    所述膨化氟树脂膜背向所述基板的一面上设置有所述铜箔层。
  2. 根据权利要求1所述的覆铜板，其特征在于，所述膨化氟树脂膜包括膨化基膜和填充膜，所述微孔结构位于所述膨化基膜中；
    所述填充膜分别位于所述膨化基膜相对的两面上，且所述填充膜填充所述微孔结构。
  3. 根据权利要求2所述的覆铜板，其特征在于，所述填充膜为氟树脂膜，所述氟树脂膜设置在所述膨化基膜上。
  4. 根据权利要求2所述的覆铜板，其特征在于，所述填充膜为第二氟树脂乳液膜。
  5. 根据权利要求4所述的覆铜板，其特征在于，还包括氟树脂膜，所述氟树脂膜设置在所述第二氟树脂乳液膜背向所述膨化基膜的一面上。
  6. 根据权利要求1-5任一所述的覆铜板，其特征在于，还包括增强件，所述增强件设置在所述第一氟树脂乳液膜内。
  7. 根据权利要求2-5任一所述的覆铜板，其特征在于，所述膨化基膜、所述填充膜、所述第一氟树脂乳液膜的成型材料至少包括：聚四氟乙烯、可熔性聚四氟乙烯或全氟乙烯丙烯共聚物。
  8. 根据权利要求2-7任一所述的覆铜板，其特征在于，所述基板至少包括玻璃纤维布。
  9. 一种覆铜板的制备方法，其特征在于，所述方法包括：
    提供基板；
    获得第一氟树脂乳液，将所述基板浸入所述第一氟树脂乳液中，以在所述基板相对的两面上形成第一氟树脂乳液膜；
    获得膨化氟树脂膜，所述膨化氟树脂膜具有多个微孔结构；
    将所述膨化氟树脂膜设置在所述第一氟树脂乳液膜背向所述基板的一面上；
    提供铜箔层，将所述铜箔层设置在所述膨化氟树脂膜背向所述基板的一面上；
    压合，获得所述覆铜板。
  10. 根据权利要求9所述的制备方法，其特征在于，所述膨化氟树脂膜包括膨化基膜和填充膜，所述微孔结构位于所述膨化基膜中，所述填充膜用于填充所述微孔结构；
    所述获得所述膨化树脂膜包括：
    获得膨化基膜；
    在所述膨化基膜相对的两面上设置填充膜。
  11. 根据权利要求10所述的制备方法，其特征在于，所述填充膜为氟树脂膜；
    所述在所述膨化基膜相对的两面上设置填充膜包括：
    提供氟树脂膜，将氟树脂膜设置在膨化基膜相对的两面上。
  12. 根据权利要求10所述的制备方法，其特征在于，所述填充膜为第二氟树脂乳液膜；
    所述在所述膨化基膜相对的两面上设置填充膜包括：
    获得第二氟树脂乳液，将所述膨化基膜浸入所述第二氟树脂乳液中，以在所述膨化基膜相对的两面上形成第二氟树脂乳液膜。
  13. 根据权利要求12所述的制备方法，其特征在于，所述覆铜板还包括氟树脂膜，所述将所述膨化氟树脂膜设置在所述第一氟树脂乳液膜背向所述基板的一面上后，所述方法还包括：
    提供氟树脂膜，将所述氟树脂膜设置在所述第二氟树脂乳液膜背向所述膨化基膜的一面上。
  14. 根据权利要求9-13任一所述的方法，其特征在于，所述获得第一氟树脂乳液之后还包括：
    在所述第一氟树脂乳液中添加增强件。
  15. 根据权利要求9-14任一所述的方法，其特征在于，所述提供铜箔层之后还包括：
    对所述铜箔层表面进行粗化处理；
    对经粗化处理后的所述铜箔层的表面进行氟化处理。
  16. 一种柔性电路板，其特征在于，至少包括线路结构和上述权利要求1-8任一所述的覆铜板，所述线路结构设置在所述覆铜板上。
  17. 一种电子设备，其特征在于，至少包括壳体和上述权利要求16所述的柔性电路板，所述柔性电路板设置在所述壳体内。
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JP2016046433A (ja) * 2014-08-25 2016-04-04 住友電工ファインポリマー株式会社 プリント配線板及びプリント配線板用基板
CN108358505A (zh) * 2017-01-26 2018-08-03 上海安缔诺科技有限公司 微波介质陶瓷粉填充氟树脂中间介质层及其制备方法
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JPS60214941A (ja) * 1984-04-10 1985-10-28 株式会社　潤工社 プリント基板
JPH01225539A (ja) * 1988-03-04 1989-09-08 Junkosha Co Ltd 積層板
CN102260378B (zh) * 2011-05-06 2013-03-20 广东生益科技股份有限公司 复合材料、用其制作的高频电路基板及其制作方法
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CN108358505A (zh) * 2017-01-26 2018-08-03 上海安缔诺科技有限公司 微波介质陶瓷粉填充氟树脂中间介质层及其制备方法
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