Prepreg article

Abstract

A prepreg article includes a dielectric substrate including a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and optionally, adjacent conductive layers disposed on a surface of the dielectric substrate.

Description

PRE P R EG ARTI CLECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This claims the benefit of priority of U.S. Provisional Application No. 63 / 538,901 filed September 18, 2023, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] With the development of high performance, high functionality, and networking of computers and information communication apparatuses, operation signals tend to be high-frequency in order to transmit and process large-capacity information at high speed, and thus, there is a demand for materials for circuit substrates, particularly those using broadband electronic apparatuses such as mobile communication devices.

[0003] Prepreg materials are used along with metal-clad laminates and prepregs in constructing multilayer printed-wiring board in various electronics applications.SUMMARY

[0004] According to certain aspects of the present invention, a prepreg article includes a dielectric substrate (layer) comprising: a perfluorocopolymer matrix including a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L- glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. The article may further comprise aconductive cladding disposed on a surface of the dielectric substrate.Embodiments can include one or any combination of two or more of the following features.

[0005] In some aspects, the L-glass fabric includes yarn of L-glass, NL-glass, L2-glass, or combinations thereof.

[0006] A prepreg article may have a thickness of between 20 pm and 200 pm, 30 pm and 90 pm, or 30 pm and 60 pm.

[0007] In some aspects, a prepreg article has a dielectric constant at 10 GHz of between 2.10 and 2.70, or between 2.10 and 2.40. A dielectric substrate may have a thermal coefficient a value of between -250 ppm / °C to +50 ppm / °C over a temperature range of 0 to 100°C. In some aspects, the dielectric substrate has a dissipation factor at 10 GHz of less than 0.0015, between 0.0006 and 0.001 , or between 0.0006 and 0.0008.

[0008] A prepreg article may have a planar shape defining an X-Y plane, and in which a coefficient of thermal expansion of the prepreg article in the X-Y plane is between 5 ppm / °C and 25 ppm / °C, between 14 ppm / °C and 20 ppm / °C, or between 16 ppm / °C and 22 ppm / °C.

[0009] In some aspects, the fluorinated perfluorocopolymer includes a first fluorinated tetrafluoroethylene / hexafluoropropylene having a first melt flow rate and a second tetrafluoroethylene / hexafluoropropylene having a second melt flow rate.

[0010] In some aspects, the number of carboxyl end groups per million carbon atoms in the perfluorocopolymer matrix is sufficient for the prepreg article to form no conductive anodic filaments. In some aspects, the perfluorocopolymer matrix includes a number of carboxyl end groups per million carbon atoms sufficient to provide the prepreg article with a peel strength between the dielectric substrate and a conductive cladding of greater than 2 Ib / inch. A perfluorocopolymer matrix may include, for example, between 5 and 200 carboxyl end groups per million carbon atoms, or between 30 and 70 carboxyl end groups per million carbon atoms.

[0011] A perfluorocopolymer matrix may have a melt flow rate of between 10 g / 10 minutes and 30 g / 10 minutes, or between 10 g / 10 minutes and 20 g / 10 minutes. A perfluorocopolymer matrix may have a solder float resistance of at least 10 seconds at 288°C.

[0012] L-glass fabric may have a basis weight of less than 100 g / m2, or less than 50 g / m2. In some aspects, L-glass fabric has a thickness between 10 pm and 100 pm, or between 10 pm and 30 pm. L-glass fabric may include an aminosilane or methacrylate silane surface chemistry treatment; may be plasma- treated or corona-treated; may be impregnated with a fluoropolymer; may include a fluoropolymer coating; may have a water contact angle between 0° and 60°; and / or may be pretreated with a fluoropolymer treatment prior to incorporation into the prepreg article.

[0013] In some aspects, a dielectric substrate includes between 5 and 20 volume percent of the L-glass fabric and between 80 and 95 volume percent of the perfluorocopolymer matrix.

[0014] In some aspects, the additive material includes inorganic particles, such as but not limited to particles of cerium oxide, titanium dioxide, silicon dioxide, barium titanate, calcium titanate, zinc oxide, or combinations thereof. The additive material may include a thermoset polymer. An additive material may be present in the perfluorocopolymer matrix at a volume percent of less than 2% of the perfluorocopolymer matrix, and / or may be dispersed homogeneously throughout the perfluorocopolymer matrix.

[0015] In some aspects, a conductive cladding is disposed on two opposing surfaces of the dielectric substrate. Suitable conductive cladding may include, for example, a copper foil. Conductive cladding may be disposed on the surface of the dielectric substrate by a lamination process. In some aspects, the conductive cladding has a thickness of less than 72 pm, or between 5 pm and 18 pm; a root mean square (RMS) roughness of less than 1 pm, and / or an RMS roughness of less than 0.5 pm.

[0016] A printed-wiring board may include a prepreg article as described herein with an adjacent conductive cladding, such as copper clad laminate, having a conductor pattern. In some aspects, a through-hole is defined through a thickness of the board and optionally a copper film plating the through-hole.

[0017] A multilayer printed-wiring board may include a multilayer laminated structure with multiple printed-wiring boards as described herein. In someaspects, a thermoplastic adhesive is disposed between adjacent printed-wiring boards in the laminated structure. The thermoplastic adhesive may be bonded at a temperature between 0 and 200°C below a melting point of the perfluorocopolymer matrix; or between 0 and 50°C below the melting point of the perfluorocopolymer matrix. In some aspects, a thermoset adhesive is disposed between adjacent printed-wiring boards in the laminated structure. The thermoset adhesive may be cured at a temperature of between 150°C and 250°C.

[0018] Multilayer printed-wiring boards may include a through-hole defined through at least a portion of a thickness of the multilayer printed-wiring board; and optionally a copper film plating the through-hole.

[0019] An antenna usable with a 5G communications network may include a printed-wiring board as described herein.

[0020] According to certain aspects of the present invention, a method of making a multilayer printed-wiring board includes providing multiple printed- wiring boards as described herein; and laminating the multiple printed-wiring boards to form a multilayer laminated structure. Laminating the multiple printed- wiring boards may include adhering adjacent printed-wiring boards using a thermoplastic prepreg. The thermoplastic prepreg may be bonded at a temperature between 0 and 100°C below a melting point of the adjacent perfluorocopolymer matrix, or at a temperature between 0 and 50°C below the melting point of the adjacent perfluorocopolymer matrix. The method may include defining a through-hole through at least a portion of a thickness of the multilayer laminated structure by way of, for example, an ultraviolet laser drilling process.

[0021] According to certain aspects of the present invention, a method of making a laminate article includes: forming a layered article having first and second polymer films, each film having a perfluorocopolymer matrix including a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer and an additive material capable of absorbing ultraviolet light; an L-glass fabric disposed between the first and second polymer films; and a conductive cladding disposed in contact with the first film; and applying heat and pressure to the layered article to form the laminate article. Applying heat and pressure to the layered article may include compressing the layered article in a heated platen and / or processing the layered article in a roll-to-roll lamination process. Applying heat and pressure to the layered article may include applying to the layered article a temperature between 10°C and 80°C greater than a melting point of the perfluorocopolymer matrix. Applying heat and pressure to the layered article may include applying to the layered article a temperature of between 250°C and 350°C. Applying heat and pressure to the layered article may include applying to the layered article a pressure of between 50 psi and 1000 psi.

[0022] In some aspects, the first and second films are formed in a melt processing and extrusion process. The method may include treating the L-glass fabric with a fluoropolymer treatment. Such treatment may include coating the L- glass fabric with a fluoropolymer coating; this may include coating the L-glass fabric in a solution coating process and / or depositing fluoropolymer particles on a surface of the L-glass fabric.

[0023] According to some aspects, a multilayer laminate includes a first layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. The multilayer laminate may have a second layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinated perfluorocopolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate. In some aspects, conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer.

[0024] According to some aspects, a multilayer laminate includes a first layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. The multilayer laminate may have a second layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinated perfluorocopolymer; a quartz fabric embedded in the perfluorocopolymer matrix;and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate. In some aspects, conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer.

[0025] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 is a diagram of a flexible prepreg article.

[0027] Fig. 2 shows insertion loss values for various multilayer laminates.DETAILED DESCRIPTION

[0028] Articles and methods of the present invention relate to prepreg articles having a dielectric substrate including: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. Prepreg articles of the present invention may be flexible. Prepreg articles as described herein may have a low dielectric constant and low dissipation at high frequencies, e.g., at 10 GHz. Prepreg articles described herein may have properties that are beneficial for use as substrates forprinted-wiring boards in high-frequency applications, such as for antennas for use in 5G cellular communications networks or for use with enterprise server communication hardware, among other applications.

[0029] Referring to Fig. 1 , a prepreg article 100 includes a dielectric substrate 102 formed of a perfluorocopolymer matrix 110 with an L-glass fabric.

[0030] As discussed further below, the perfluorocopolymer matrix 110 may provide the dielectric substrate 102 with a low dielectric constant and low dissipation factor. The perfluorocopolymer matrix 110 includes a fully fluorinated perfluorocopolymer (referred to here as a “fluorinated perfluorocopolymer”), such as fully fluorinated tetrafluoroethylene / hexafluoropropylene copolymers.

[0031] In some examples, the composition of the perfluorocopolymer is indicated by a number (e.g., a number concentration) of carboxyl end groups, present in the perfluorocopolymer. Non-limiting examples of such carboxyl end groups include -COF, -CONH2, -CO2CH3, and -CO2H and are determined by polymerization aspects such as choice of polymerization medium, initiator, chain transfer agent, if any, and buffer if any. The number of carboxyl end groups per million carbon atoms present in the perfluorocopolymer can be between 5 and 200, alternately between 30 and 70, or alternately between 35 and 55. This number of carboxyl end groups can be selected to achieve sufficient adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108 and the adjacent optional conductive cladding, when present, while also achieving a sufficiently low dielectric constant and dissipation factor. For instance, thenumber of carboxyl end groups can be selected such that there is no CAF formation in the prepreg article 100.

[0032] The analysis and quantification of carboxyl end groups in perfluorocopolymers can be carried out by infrared spectroscopy methods known to those of ordinary skill in the field of perfluoropolymers. The presence of the thermally stable end group -CF3 (the product of fluorination) may be deduced from the absence of unstable end groups existing after the fluorine treatment. The presence of -CF3 end groups may result in reduced dissipation factor of the perfluorocopolymer as compared to other end groups.

[0033] In some aspects, the perfluorocopolymers are made by aqueous dispersion polymerization, and as-polymerized can contain at least about 400 reactive end groups per 106carbon atoms. Most of these end groups are thermally unstable in the sense that when exposed to heat, such as encountered during extrusion and film formation, or film lamination conditions, they can undergo chemical reaction such as decomposition and decarboxylation, either discoloring the extruded polymer or filling it with non-uniform bubbles or both. To make the fluorinated perfluorocopolymers described here, polymerized perfluorocopolymer is stabilized to replace substantially all of the reactive end groups by thermally stable -CF3 end groups. An example method of stabilization is exposure of the fluoropolymer to a fluorinating agent, such as elemental fluorine - a stabilization process known to those of average skill in the field of perfluoropolymers.

[0034] The perfluorocopolymer matrix 110 may include an L-glass fabric 108, such as a woven L-glass fabric (e.g., an L-glass, NL-glass, or L2-glass yarn woven into a fabric) embedded therein. In some aspects, the L-glass fabric 108 that is embedded in the perfluorocopolymer matrix 1 10 may be formed of spread glass (e.g., L-glass) bundles. The L-glass fabric 108 may enable the coefficient of thermal expansion (CTE) in the x-y plane of the dielectric substrate 102 to match the CTE of adjacent optional conductive cladding when present. As a result, the presence of L-glass fabric 108 may result in a prepreg article 100 that has a high degree of flatness, e.g., a degree of flatness that is sufficient to enable registration between multiple layers of prepreg articles during a drilling process. For instance, in a multilayer laminate comprising multiple prepreg articles 100, a high degree of flatness enables registration during drilling of vias through the thickness of the multilayer laminate structure. Without being bound by theory, it is believed that the difference between the coefficient of thermal expansion (CTE) of the L-glass fabric 108 and the CTE of the perfluorocopolymer matrix 110, together with the relatively low modulus of L-glass fabric 108 (e.g., as compared to quartz fabric), is such that the contraction of the L-glass fabric 108 during cooling of the multilayer laminate is small enough to avoid generation of waviness in the multilayer laminate.

[0035] The composition of L-glass is shown in Table 1 . The composition of Eglass is also shown for comparison. L-glass has a lower CTE than the perfluorocopolymer matrix 110, such as a CTE of between 2.5 ppm / °C and 4 ppm / °C, between 2.5 ppm / °C and 3 ppm / °C, or between 3 ppm / °C and 4ppm / °C. By adjusting the volume ratio of the perfluorocopolymer matrix 110 to the woven glass fabric 108, the CTE of the dielectric substrate 102 in the x-y plane can be matched to the in-plane CTE of the optional metal foil, thereby providing the prepreg article 100 with dimensional stability. For instance, the dielectric substrate 102 can include between 5 and 20 volume percent of woven L-glass fabric 108 and between 80 and 95 volume percent of the perfluorocopolymer matrix 110. The CTE in the x-y plane of the dielectric substrate 102 can be between 5 and 25 ppm / °C, between 16 and 22 ppm / °C, or between 14 and 20 ppm / °C, thereby providing a dimensional stability of less than about 0.1 %. By contrast, the CTE of the perfluorocopolymer matrix 110 alone can be between 100 and 300 ppm / °C.Table 1. Composition of L-glass

[0036] L-glass has a low dielectric constant, such as a dielectric constant of between 4.0 and 5.0 at 10 GHz, between 4.5 and 5.0 GHz, or between 4.5 and4.8 GHz. Thus, the dielectric substrate 102 may have a low dielectric constant and low loss even with the presence of the L-glass fabric 108 embedded in the perfluorocopolymer matrix 110. L-glass also has a low dissipation factor, such asa dissipation factor of between 0.002 and 0.003 at 10 GHz, 0.002 at 10 GHz, 0.0023 at 10 GHz, 0.0025 at 10 GHz, 0.0028 at 10 GHz, or 0.003 at 10 GHz.

[0037] The woven L-glass fabric 108 has a thickness of less than about 100 pm, between about 30 pm and 100 pm, or between 10 pm and 30 pm, helping a thin dielectric substrate 102 to be achieved. The basis weight of the L-glass fabric 108 is less than about 1000 g / m2, less than about 50 g / m2, or between 10 g / m2and 50 g / m2. In a specific example, the L-glass fabric 108 is an NL1035 NL- glass fabric (Asahi Kasei Corporation, Tokyo, Japan).

[0038] In some examples, the woven L-glass fabric 108 is subjected to one or more surface treatments to improve the wettability of the fibers of the woven L- glass fabric 108 by the perfluorocopolymer matrix 110, to remove residual organic matter, or to mechanically alter the surface of the fibers to enhance adhesion between the fibers of the L-glass fabric 108 and the perfluorocopolymer matrix 110. The objective of the surface treatment can be to facilitate substantially complete wetting of the L-glass fibers by the perfluorocopolymer such that the perfluorocopolymer fully encapsulates the L-glass fiber (e.g., L- glass yarn) bundles. Sufficient encapsulation of and adhesion to the L-glass fiber bundles by the perfluorocopolymer enables the dielectric substrate 102 to be substantially free of voids, e.g., non-porous, which in turn helps prevent formation of conductive anodic filaments and occurrence of electromigration during postprocessing, e.g., during formation of vias through the thickness of the prepreg article 100.

[0039] The surface treatment can include a thermal treatment to remove residual organic matter (e.g., residual starches) from the surface of the L-glass fibers such that a clean L-glass surface is exposed to the perfluorocopolymer. The surface treatment can include the addition of adhesion promotors such as methacrylate silane, vinyl silane, aminosilane, or fluorosilane on the surface of the L-glass fibers. The surface treatment can include a plasma or corona treatment. The surface treatment can include treatment with a polymeric coating, such as a fluoropolymer, e.g., a perfluoroalkane (PFA), fluorinated ethylene propylene (FEP), or Teflon™ amorphous fluoropolymer, to form a polymer (e.g., fluoropolymer) film on the surface of the L-glass fibers. For instance, the L-glass fabric can be immersed in a solution containing a dispersion of the fluoropolymer to form a monolayer of the fluoropolymer on the surface of the L-glass fibers. The surface treatment can include treatment with a fluorinated silane to form a layer, e.g., a monolayer, of fluorinated molecules on the surface of the L-glass fibers. A combination of surface treatments can be applied, such as a thermal treatment followed by a plasma or corona treatment. The surface treatment(s) applied to the L-glass fabric 108 can improve wettability of the fibers by the perfluorocopolymer matrix 110, enabling better encapsulation of the fibers of the L-glass fabric 108 by the perfluorocopolymer matrix 110 and stronger adhesion between the perfluorocopolymer matrix 110 and the fibers of the L-glass fabric 108, thereby contributing to formation of a void-free dielectric substrate 102 that is resistant to CAF formation.

[0040] The wettability of the L-glass fabric 108 can be characterized by the water contact angle (WCA). The L-glass fabric 108 following surface treatment can have a WCA of between 0° and 60°. An additive material 112 that is capable of absorbing ultraviolet (UV) light, e.g., light having a wavelength of between 180 nm and 400 nm, may be dispersed in the perfluorocopolymer matrix 110. The presence of the UV-responsive additive material 112 may enable the prepreg article 100 to be drilled by a UV laser, e.g., for formation of circuit structures such as vias through the thickness of the prepreg article 100.

[0041] Referring again to Fig. 1 , the additive material 112 may be dispersed, e.g., homogeneously dispersed, in the perfluorocopolymer matrix 1 10. The additive material 112 is a material that is capable of absorbing UV light such that the prepreg article 100 can be processed by UV drilling processes, e.g., to form vias between the top and bottom surfaces 106 of the prepreg article 100. The additive material 112 may be present in the dielectric substrate 102 at a volume percentage of less than 3%, between 1 and 3 volume percent of the dielectric substrate 102, 1 vol.%, 1.25 vol. %, 1.5 vol. %, 2 vol.%, or 2.5 vol% of the dielectric substrate 102. The additive material 112 can be a material that has a relatively low dielectric constant, such as a dielectric constant of between 10 and 1000, so that the inclusion of the additive material 112 in the perfluorocopolymer matrix 110 does not significantly increase the dielectric constant or dissipation factor of the dielectric substrate 102. For instance, the inclusion of the additive material 112 at less than 3% by volume of the dielectric substrate 102 can causethe dielectric constant of the dielectric substrate 102 to increase by less than 10%, less than 5%, or less than 2%.

[0042] In some aspects, the additive material 112 comprises inorganic particles such as particles of cerium oxide (CeCh), titanium dioxide (TiCk), silicon dioxide (SiCh), barium titanate (BaTiOs), calcium titanate (CaTiOs), zinc oxide (ZnO), or other suitable materials, and combinations thereof. The particles may have a diameter of less than about 5 pm, less than about 2 pm, less than about 1 pm, or less than about 0.5 pm, e.g., between 0.1 pm and 0.5 pm. For instance, smaller particles often are more effective absorbers of UV light than larger particles of similar composition. In some examples, the additive material 112 is an organic (e.g., polymeric) additive, such as a low loss thermoset material such as polyimide, that is blended into the perfluorocopolymer matrix 110. In some examples, both inorganic particles and an organic additive are used as additive materials.

[0043] In an optional embodiment, a conductive cladding, such as a copper foil, may be disposed on one or both surfaces of the dielectric substrate 102. The adjacent optional conductive cladding, such as copper foil layers, of the prepreg article provides a platform on which conductive patterns can be defined, e.g., such that the flexible laminate can be used as a printed-wiring board. The conductive cladding may be variously patterned by printing and etching and can also include additive metalization.

[0044] In some examples, the adjacent optional conductive cladding are disposed on the surface(s) 106 of the dielectric substrate 102 by a mechanicalprocess, e.g., a roll-to-roll lamination process. For instance, the conductive cladding can be an electrodeposited copper foil or a rolled copper foil. In some examples, the conductive cladding such as copper foil is deposited, e.g., electrolytically plated onto the dielectric substrate 102.

[0045] The optional conductive cladding may have a thickness of less than about 72 pm, less than about 18 pm, or between 10 pm and 18 pm. The optional conductive cladding may have a low root mean square (RMS) roughness, such as an RMS roughness of less than 1 pm, or less than 0.5 pm, as measured by non-contact interferometry. The low RMS roughness of the optional conductive cladding helps to maintain the low insertion loss of the circuitry made from the prepreg article 100. In some examples, the RMS roughness of the optional conductive cladding is selected to balance low insertion loss (e.g., achievable by a low RMS roughness) with good adhesion between the optional conductive cladding and the dielectric substrate 102 (e.g., achievable by higher RMS roughness). For instance, as discussed above, a sufficiently high peel strength between the dielectric substrate 102 and the optional conductive cladding is a peel strength that is greater than 2 Ib / inch, greater than 4 Ib / inch, between 2 and 20 Ib / inch, or between 4 and 20 Ib / inch.

[0046] The optional conductive cladding such as copper foil may have a purity of at least about 99.9%. The surface chemistry of the optional conductive cladding such as copper foil can be affected by surface treatments such as treatment with zinc, thermal stability additives, and treatments to resist oxidation.These surface treatments can be applied to one or both surfaces of the optionalconductive cladding such as copper foil. Elements such as iron and zinc have been found to be effective in enhancing the peel strength without appreciably degrading the electrical performance of the dielectric substrate 102.

[0047] The prepreg article 100 is a planar structure that may have a thickness along the z-axis of less than about 200 pm, less than about 100 pm, between 20 pm and 200 pm, between 30 pm and 90 pm, or between 30 pm and 60 pm. The thickness of the dielectric substrate 102 may constitute most of the thickness of the prepreg article 100. For instance, the dielectric substrate 102 may have a thickness along the z-axis of less than about 200 pm, less than about 100 pm, between 20 pm and 200 pm, between 30 pm and 90 pm, or between 30 pm and 60 pm.

[0048] The dielectric substrate 102 of the, prepreg article 100 may have a low dielectric constant, e.g., a dielectric constant at 10 GHz of less than about 2.7, between 2.1 and 2.7, or between 2.1 and 2.4. The dielectric substrate 102 may have a thermal coefficient with a value of between -250 and 50 ppm / °C, e.g., between -100 and 50 ppm / °C or between -50 and 25 ppm / °C, over a temperature range of 0 to 100°C. The dielectric substrate 102 may also have a low dissipation factor, e.g., a dissipation factor at 10 GHz of less than 0.0015, such as less than 0.001 or less than 0.0008, e.g., between 0.0002 and 0.001 , e.g., between 0.0006 and 0.001 , e.g., between 0.0006 and 0.0008.

[0049] The improved electrical properties (e.g., low dielectric constant and low dissipation factor) of the prepreg article 100 make it possible for designers torealize improvements in insertion loss, e.g., of up to 25% or more for a given characteristic impedance versus incumbent flexible materials.

[0050] The coefficient of thermal expansion (CTE) of the dielectric substrate 102 and the CTE of adjacent optional conductive cladding layers are similar in the x-y plane of the prepreg article 100. For instance, when the adjacent optional conductive cladding layer is a copper foil, the CTE in the x-y plane of the dielectric substrate 102 can be between 5 and 25 ppm / °C, e.g., between 16 and 22 ppm / °C, e.g., or between 14 and 20 ppm / °C. The matching of CTE values between the dielectric substrate 102 and adjacent optional conductive cladding layer provides the prepreg article 100 with dimensional stability, e.g., a dimensional stability of less than about 0.1 %, e.g., such that the prepreg article 100 maintains its original dimensions within about 0.1% when subjected to a change in temperature.

[0051] The adjacent optional conductive cladding layers of the prepreg article 100 may be adhered strongly to the dielectric substrate. For instance, a peel strength between the dielectric substrate 102 and the adjacent optional conductive cladding may be greater than 2 lb. / inch, e.g., greater than 4 lb. / inch, e.g., between 2 and 20 lb. / inch, or between 4 and 20 lb. / inch. The prepreg article 100 may be mechanically robust against bending and can be flexed over bend radii typically found in electronic devices without failure of any of the components of the prepreg article 100. This flexibility facilitates installation of the prepreg article 100 into devices.

[0052] The prepreg article 100 can be drilled by a UV laser and is compatible with metallization techniques, e.g., plasma metallization, such that through-holes can be formed through the thickness of the prepreg article 100 (e.g., along the z- axis of the prepreg article 100). The dielectric substrate 102 of the prepreg article 100 has a solder float resistance at 288°C of at least 5 seconds, at least 10 seconds, at least 30 seconds, or at least 60 seconds, e.g., between 5 and 20 seconds, between 10 and 15 seconds, between 10 and 30 seconds, between 10 and 60 seconds, or between 30 and 60 seconds.

[0053] The prepreg article 100 can be used for a printed-wiring board, e.g., for flexible printed circuit board antennas. For instance, the dimensions and electrical properties of the prepreg article 100 can make the prepreg article 100 suitable for use in high-frequency applications, such as for antennas for mobile devices usable on 5G communications networks, as discussed further below, or for use with automotive radar or other high-frequency applications. In some examples, multiple prepreg articles 100 can themselves be laminated into a multilayer circuit board structure. The prepreg article 100 is substantially void- free and resistant to formation of conductive anodic filaments, which contributes to electrical reliability of the prepreg article 100 as printed-wiring board substrate.

[0054] The low dielectric constant and low dissipation factor of the dielectric substrate 102 of the prepreg article 100 are due, at least in part, to the composition of the perfluorocopolymer matrix 110. The perfluorocopolymer matrix 110 includes a fully fluorinated perfluorocopolymer, such as a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer.

[0055] A sufficiently low dielectric constant for the dielectric substrate 102 is a dielectric constant at 10 GHz of less than about 2.7, e.g., between 2.1 and 2.7, e.g., between 2.1 and 2.4. A sufficiently low dissipation factor for the dielectric substrate 102 is a dissipation factor at 10 GHz of less than 0.0015, such as between 0.0002 and 0.001 , e.g., between 0.0006 to 0.001 , e.g., between 0.0006 and 0.0008.

[0056] In some examples, the sufficiency of the adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108 and the optional conductive cladding is determined by the peel strength between the dielectric substrate 102 and the optional adjacent conductive cladding layer. For instance, the adhesion is sufficient if the peel strength is greater than 2 Ib. / inch, e.g., greater than 4 Ib. / inch, e.g., between 2 and 20 Ib. / inch or between 4 and 20 Ib. / inch. In some examples, the sufficiency of the adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108 and the adjacent optional conductive cladding is determined by the tendency of the prepreg article 100 to resist formation of conductive anodic filaments (CAF), discussed further below.

[0057] The melt flow rate (MFR) of the fluorinated perfluorocopolymer can affect the adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108 and the adjacent optional conductive cladding layers. A polymer with a high MFR flows more readily during lamination of the prepreg article 100 than can a polymer with a lower MFR. The flow of the perfluorocopolymer matrix 110 during a lamination process (discussed in more detail below) may enable theperfluorocopolymer matrix 110 to fully encapsulate the fibers of the L-glass fabric 108, resulting in a dielectric substrate 102 that is substantially free of voids, e.g., non-porous. A void-free dielectric substrate 102 may be resistant to CAF formation.

[0058] The fluorinated perfluorocopolymer has a high melting point, such as between 200°C and 300°C, e.g., between 220°C and 300°C, between 240°C and 280°C, e.g., about 265°C. The high melting point of the fluorinated perfluorocopolymer results in the perfluorocopolymer matrix 100 being resistant to high temperatures and provides the dielectric substrate 102 with a sufficient solder float resistance, such as a solder float resistance at 288°C of at least 5 seconds, at least 10 seconds, at least 30 seconds, or at least 60 seconds, e.g., between 5 and 20 seconds, between 10 and 15 seconds, between 10 and 30 seconds, between 10 and 60 seconds, or between 30 and 60 seconds, as measured according to the IPC-TM-650 test method.

[0059] The composition of the perfluorocopolymer matrix 1 10 can be selected to enable the dielectric substrate 102 to be compatible with plasma treatment, e.g., for metallization of through-holes formed through the thickness of the prepreg article 100.

[0060] As discussed above, the dielectric substrate 102 of the prepreg article 100 is substantially free of voids and has sufficient adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108, which enables the prepreg article 100 to resist formation of conductive anodic filaments (CAF). CAF are metallic filaments that form, e.g., in voids or weak areas of a dielectricsubstrate due to electromigration of metal induced by, e.g., application of an electric field. CAF formation can lead to electric failure, e.g., when the CAF create short-circuit pathways between vias through the printed-wiring board. A prepreg article can be considered as having no CAF formation when there is less than a one decade drop in resistance throughout the duration of a test of resistance of greater than 10 MOhms after an initial 96 hour equilibration period. A CAF test can last up to 1000 hours or more with applied voltages of between 100 VDC and 1000 VDC, e.g., depending on application criteria.

[0061] Referring again to Fig. 1 , the dielectric substrate 102 of the prepreg article 100 may be substantially void-free and has strong adhesion between the perfluorocopolymer matrix 110 and the L-glass fabric 108. This is achieved, e.g., by the nature of the perfluorocopolymer (e.g., the number concentration of reactive end groups), the surface chemistry of the L-glass fabric 108, and manufacturing parameters such as pressure and temperature (discussed below). In addition, in some aspects, the arrangement of the L-glass fabric 108 in the perfluorocopolymer matrix 110 is such that there is substantially no contact between fibers of the L-glass fabric 108 and the nearest optional conductive cladding. As a result, CAF formation in the dielectric substrate 102 is minimal and the prepreg article 100 can be used as a reliable and robust printed-wiring board substrate.

[0062] Multiple prepreg articles 100 can be laminated together to form a multi-layer laminate or a multi-layer printed-wiring board. A central prepreg article100 may include top and bottom conductive claddings. Prepreg articles 100 caneach include a single optional conductive cladding. The prepreg articles 100 can be bonded to a central prepreg article 100 by adhesive layers. The adhesive layers can be, e.g., an adhesive that can be bonded at a temperature below the melting point of the perfluorocopolymer matrix 110 of the prepreg articles 100. In some examples, the adhesive layer is a thermoplastic adhesive that is capable of being bonded at a temperature between 0°C and 50°C less than the melting point of the adjacent laminate perfluorocopolymer matrix 110. Printed-wiring boards made from the prepreg articles 100 described here can be used in various applications, e.g., high-frequency applications such as high-frequency communications applications. For instance, a present printed-wiring board including one or more flexible laminates prepreg articles 100 can be used for an antenna or antenna feedline for a communication device (e.g., a mobile communication devices) operable on a 5G communications network. For instance, prepreg articles 100 can be useful as substrates for printed-wiring boards for communication device antennas or antenna feed lines to connect electronic components of the device that are located on different planes. A present printed-wiring board including one or more prepreg articles 100 can be used in communications network equipment, such as in a transmission antenna in a tower of a cellular communications network. Printed-wiring boards including prepreg articles 100 can also be used in other applications, such as in camera feedlines in mobile computing devices.

[0063] According to some aspects, a multilayer laminate includes a first layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprisinga fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. The multilayer laminate may have a second layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinated perfluorocopolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate. In some aspects, conductive cladding is disposed on one surface of the dielectric substrate of the second layer. In some aspects, conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer. In some aspects, conductive cladding is disposed on opposing surfaces of the dielectric substrate of the second layer.

[0064] According to some aspects, a multilayer laminate includes a first layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light. The multilayer laminate may have a second layer comprising a dielectric substrate having: a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinatedperfluorocopolymer; a quartz fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate. In some aspects, conductive cladding is disposed on one surface of the dielectric substrate of the second layer. In some aspects, conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer. In some aspects, conductive cladding is disposed on opposing surfaces of the dielectric substrate of the second layer.

[0065] Multilayer laminates as described herein may provide unexpected benefits. For example, electrical performance benefits include lower dielectric constant and loss tangent than conventional commercial thermoset resin based prepregs / systems. These characteristics permit significant improvements in design flexibility and performance (insertion loss, in particular).

[0066] Additionally, such multilayer laminates provide benefits related to adhesion. Adhesion of the prepreg articles 100 described herein provide better (i.e., stronger) adhesion to better (i.e. , smoother) copper foil for use in foillamination constructions, such as for outer layers on printed-wiring boards.Combinations of layers of multilayer laminates as described herein provide lower insertion loss traces on such outer layer, as they are afforded favorable geometry by lower Dk and smoother copper by improved adhesion.

[0067] The prepreg articles 100 described here can be manufactured by well- known lamination processes. For example, the L-glass fabric 108 can bedisposed between two perfluorocopolymer films. Each perfluorocopolymer film may have a thickness of between 10 pm and 100 pm, e.g., between 10 pm and 80 pm, or between 10 pm and 60 pm. The optional conductive claddings can be disposed on the respective perfluorocopolymer film. For example, the optional conductive claddings are electrodeposited copper foils or rolled annealed copper foils. Each conductive cladding has a thickness of less than about 72 pm, e.g., less than about 18 pm, e.g., or between 10 pm and 18 pm.

[0068] The layers of aforementioned materials may be heated and compressed to consolidate the layers of the material, thereby forming the prepreg article 100. The parameters of the lamination process (e.g., temperature, time, and pressure) are selected to achieve a target viscosity of the perfluorocopolymer that enables the perfluorocopolymer to flow, thereby wetting and encapsulating the glass bundles of the L-glass fabric 108 and enabling good adhesion between the perfluorocopolymer and the optional conductive claddings. The temperature can be greater than the melting point of the perfluorocopolymer, e.g., between 10°C and 100°C higher than the melting point of the perfluorocopolymer. For instance, the temperature can be between 275°C and 375°C, e.g., between 290°C and 350°C, e.g., 290°C, 310°C, 330°C, or 350°C. The temperature ramp rate can be between 1 and 5°C / minute, e.g., 1 °C / minute, 2°C / minute, 3°C / minute, or 4°C / minute. The pressure applied to the layers of material can be between 100 psi and 1000 psi, e.g., between 50 psi and 1000 psi, or between 100 psi and 6000 psi. The dwell time (e.g., for a static laminationprocess) can be between 30 minutes and 120 minutes, e.g., 30 minutes, 60 minutes, 90 minutes, or 120 minutes.Examples

[0069] The following polymers are used in these examples.

[0070] FEP1 : A highly fluorinated melt processable resin having an MFR of ~ 7 g / 10 min comprised of ~ 11 .75% HFP (hexafluoropropylene) & ~ 88.25% TFE (tetrafluoroethylene) where the number of carboxyl end groups per million carbon atoms in the resin is between 20 and 40.

[0071] FEP2: A highly fluorinated melt processable resin having an MFR of ~ 20 g / 10 min comprised of ~ 10.4% HFP & ~ 1 .2% PEVE, & 88.4 % TFE where the number of carboxyl end groups per million carbon atoms in the resin is between 20 and 40.

[0072] FEP3: A partially fluorinated melt processable resin having an MFR of ~ 30 g / 10 min comprised of ~ 10.4% HFP & ~ 1 .2% PEVE, & 88.4 % TFE where the number of carboxyl end groups per million carbon atoms in the resin is between 100 and 200.Example 1 : Mechanical characterization of prepreg article with L-glass fabric

[0073] Experiments were performed to investigate the properties of the prepreg article. A mixture comprised of ~ 31 % FEP1 , ~60% FEP2, ~ 8% FEP3 along with 1 wt% Chemours TiPure™ R101 Titanium Dioxide were compounded in the melt to create a blend with an MFR of ~ 15 g / 10 min and total carboxyl end groups per million carbon atoms between 30 and 60. This mixture wassubsequently cast into an ~ 56 pm film which was in turn corona treated on one side to enhance adhesion where the corona treated side was placed in direct contact with the reinforcement. A layer of the FEP film was placed on both sides of the NL1035 L-glass fabric from Asahi Kasei (Japan) to form a prepreg article. The thickness of the perfluorocopolymer films used to create the laminate was 56 pm. The thickness of the release material was 50 pm. Materials were laminated in a hot oil vacuum press at a dwell temperature of 300°C and a pressure of 200 psi, with a dwell time of 60 minutes, a vacuum of 1 atm, and a ramp rate of 2°C / minute. Prior to testing, samples were allowed to equilibrate at 23°C and 50% relative humidity for 24 hours.

[0074] The prepreg article was tested for various properties including squeeze-out, release quality, thickness, wicking, 288°C / 60sec solder float, crosssections, resin content, density, dielectric constant, dissipation factor, and dimensional stability. The test methods used to perform these tests are as follows:- Squeeze-out: measurement of resin flow from parts, average of four sides reported.- Release quality: internal qualitative assessment where a score of 1 = bad and 5 = good.- Thickness: measurement of prepreg z-axis thickness using a Thwing- Albert ProGage in accordance with IPC TM-6502.2.18.Wicking: internal test method where ink flow measurements are made inside of a 1 / 8” punched hole with the purpose being to assess the quality of the resin to glass adhesion.- Solder float: tested at 288°C for 60 seconds using IPC TM-650 2.4.13.- Cross-section: optical micro-section inspection technique in accordance with IPC TM-650 2.1.1.- Resin Content: tested in accordance with IPC TM-6502.3.16.1c.- Density: measurement of specific gravity in accordance with IPC TM-650 2.3.5b.- Dielectric constant: 10GHz in-plane measurement in accordance with IPC TM-650 2.5.5.15.- Dissipation factor: 10GHz in-plane measurement in accordance with IPC TM-650 2.5.5.15.- Dimensional stability: method A measurement in accordance with IPC TM-650 2.2.4c.

[0075] The results of the testing are shown in Table 2 below.Table 2Example 2: Insertion Loss of Multilayer Laminates

[0076] Insertion loss values were modeled for various multilayer laminate compositions over a range of frequencies. Insertion Loss (dB) is calculated as 10 Log 10 (P2 / P1 ), where P1 is the initial power (transmit) and P2 is the powerafter insertion (receive). Very often, insertion loss uses a convention to report it as a negative, expressed in dB, indicating what signal power might be at points in frequency or on points along or at the receiving end of a transmission line (or signal sent wirelessly through air, space - whatever path). In this example, the same restrictions are established on circuit design features (ground plane spacing and characteristic impedance).

[0077] The values are shown in Figure 2 and are described below.

[0078] White dots / line: best curve - highest performance shown- Laminate is copper foil cladding on composite using PFA-based resin formulation (additives to enhance UV laser machining) and woven L-Glass (low Dk) reinforcement- Prepreg is FEP-based resin formulation (additives to enhance UV laser machining) and woven L-Glass (low Dk) reinforcement

[0079] White-filled dots, black line and outline: second curve - intermediate performance- Laminate is copper foil cladding on composite using PFA-based resin formulation (additives to enhance UV laser machining) and woven L-Glass (low Dk) reinforcement- Prepreg is commercially available PPS-enhanced thermoset resin system with woven L-Glass (low Dk) reinforcement

[0080] Black dots / line: third curve - highest performance for comparative system, aloneLaminate is copper clad commercially available PPS-enhanced thermoset resin system with woven L-Glass (low Dk) reinforcement- Prepreg is commercially available PPS-enhanced thermoset resin system with woven L-Glass (low Dk) reinforcement

[0081] Blue toned dots / lines shown as 4th & 5th curves- Laminate is copper clad commercially available PPS-enhanced thermoset resin system with woven L-Glass (low Dk) reinforcement- Prepreg is commercially available PPS-enhanced thermoset resin system with woven L-Glass (low Dk) reinforcement

[0082] The values in Table 2 demonstrate that a multilayer laminate within the present invention provides the highest performance, with a significant improvement in insertion loss across a broad range of frequencies. This improvement represents higher signal fidelity, with a more clear and less corrupted signal.

Claims

What is claimed is:1 . A prepreg article comprising: a dielectric substrate comprising: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light.

2. The prepreg article of claim 1 , further comprising a conductive cladding disposed on a surface of the dielectric substrate.

3. The prepreg article of claim 1 , in which the L-glass fabric comprises yarn of L-glass, NL-glass, L2-glass, or combinations thereof.

4. The prepreg article of any of the preceding claims, in which the prepreg article has a thickness of between 20 pm and 200 pm.

5. The prepreg article of claim 4, in which the thickness of the prepreg article is between 30 pm and 90 pm.

6. The prepreg article of claim 5, in which the thickness of the prepreg article is between 30 pm and 60 pm.

7. The prepreg article of any of the preceding claims, in which the dielectric substrate has a dielectric constant at 10 GHz of between 2.10 and 2.70.

8. The prepreg article of claim 7, in which the dielectric constant of the dielectric substrate is between 2.10 and 2.40.

9. The prepreg article of any of the preceding claims, in which the dielectric substrate has a thermal coefficient with a value of between -250 ppm / °C to +50 ppm / °C over a temperature range of 0 to 100 °C.

10. The prepreg article of any of the preceding claims, in which the dielectric substrate has a dissipation factor at 10 GHz of less than 0.0015.11 . The prepreg article of claim 10, in which the dielectric substrate has a dissipation factor at 10 GHz of between 0.0006 and 0.001 .

12. The prepreg article of claim 11 , in which the dissipation factor of the dielectric substrate at 10 GHz is between 0.0006 and 0.0008.

13. The prepreg article of any of the preceding claims, in which the prepreg article has a planar shape defining an X-Y plane, and in which a coefficient of thermal expansion of the prepreg article in the X-Y plane is between 5 ppm / °C and 25 ppm / °C.

14. The prepreg article of claim 13, in which the coefficient of thermal expansion of the prepreg article in the X-Y plane is between 14 ppm / °C and 20 ppm / °C.

15. The prepreg article of claim 13, in which the coefficient of thermal expansion of the prepreg article in the X-Y plane is between 16 ppm / °C and 22 ppm / °C.

16. The prepreg article of any of the preceding claims, in which the fluorinated perfluorocopolymer comprises a first fluorinated tetrafluoroethylene / hexafluoropropylene having a first melt flow rate and a second tetrafluoroethylene / hexafluoropropylene having a second melt flow rate.

17. The prepreg article of any of the preceding claims, in which a number of carboxyl end groups per million carbon atoms in the perfluorocopolymer matrix is sufficient for the prepreg article to form no conductive anodic filaments.

18. The prepreg article of any of the preceding claims, wherein the perfluorocopolymer matrix comprises a number of carboxyl end groups per million carbon atoms sufficient to provide the prepreg article with a peel strength between the dielectric substrate and a conductive cladding of greater than 2Ib / inch.

19. The prepreg article of any of the preceding claims, wherein the perfluorocopolymer matrix comprises between 5 and 200 carboxyl end groups per million carbon atoms.

20. The prepreg article of any of the preceding claims, wherein the perfluorocopolymer matrix comprises between 30 and 70 carboxyl end groups per million carbon atoms.21 . The prepreg article of any of the preceding claims, in which the perfluorocopolymer matrix has a melt flow rate of between 10 g / 10 minutes and 30 g / 10 minutes.

22. The prepreg article of any of the preceding claims, in which the perfluorocopolymer matrix has a melt flow rate of between 10 g / 10 minutes and 20 g / 10 minutes.

23. The prepreg article of any of the preceding claims, in which the perfluorocopolymer matrix has a solder float resistance of at least 10 seconds at 288°C.

24. The prepreg article of any of the preceding claims, in which the L-glass fabric has a basis weight of less than 100 g / m2.

25. The prepreg article of claim 24, in which the basis weight of the L-glass fabric is less than 50 g / m226. The prepreg article of any of the preceding claims, in which the L-glass fabric has a thickness between 10 pm and 100 pm.

27. The prepreg article of claim 26, in which the L-glass fabric has a thickness between 10 pm and 30 pm.

28. The prepreg article of any of the preceding claims, in which the L-glass fabric includes an aminosilane or methacrylate silane surface chemistry treatment.

29. The prepreg article of any of the preceding claims, in which the L-glass fabric comprises a plasma-treated or corona-treated L-glass fabric.

30. The prepreg article of any of the preceding claims, in which the L-glass fabric is impregnated with a fluoropolymer.31 . The prepreg article of any of the preceding claims, in which the L-glass fabric comprises a fluoropolymer coating.

32. The prepreg article of any of the preceding claims, in which the L-glass fabric is pretreated with a fluoropolymer treatment prior to incorporation into the prepreg article.

33. The prepreg article of any of the preceding claims, in which the dielectric substrate comprises between 5 and 20 volume percent of the L-glass fabric and between 80 and 95 volume percent of the perfluorocopolymer matrix.

34. The prepreg article of any of the preceding claims, in which a water contact angle of the L-glass fabric is between 0° and 60°.

35. The prepreg article of any of the preceding claims, in which the additive material comprises inorganic particles.

36. The prepreg article of claim 35, in which the inorganic particles comprise particles of cerium oxide, titanium dioxide, silicon dioxide, barium titanate, calcium titanate, zinc oxide, or combinations thereof.

37. The prepreg article of any of the preceding claims, in which the additive material comprises a thermoset polymer.

38. The prepreg article of any of the preceding claims, in which the additive material is present in the perfluorocopolymer matrix at a volume percent of less than 2% of the perfluorocopolymer matrix.

39. The prepreg article of any of the preceding claims, in which the additive material is dispersed homogeneously throughout the perfluorocopolymer matrix.

40. The prepreg article of any of the preceding claims, in which a conductive cladding is disposed on two opposing surfaces of the dielectric substrate.41 . The prepreg article of any of the preceding claims, wherein the prepreg article comprises a conductive cladding disposed on a surface of the dielectric substrate, and wherein the conductive cladding comprises a copper foil.

42. The prepreg article of claim 41 , in which the copper foil is disposed on the surface of the dielectric substrate by a lamination process.

43. The prepreg article of claim 41 , in which the conductive cladding has a thickness of less than 72 pm.

44. The prepreg article of claim 43, in which the thickness of the conductive cladding is between 5 pm and 18 pm.

45. The prepreg article of claim 41 , in which the conductive cladding has a root mean square (RMS) roughness of less than 1 pm.

46. The prepreg article of claim 45, in which the RMS roughness of the conductive cladding is less than 0.5 pm.

47. A printed-wiring board comprising: the prepreg article of any of the preceding claims, and an adjacent copper clad laminate having a conductor pattern.

48. The printed-wiring board of claim 47, in which a through-hole is defined through a thickness of the board; and comprising a copper film plating the through-hole.

49. A multilayer printed-wiring board comprising: a multilayer laminated structure comprising multiple printed-wiring boards according to claims 47 or 48.

50. The multilayer printed-wiring board of claim 49, comprising a thermoplastic adhesive disposed between adjacent printed-wiring boards in the laminated structure.51 . The multilayer printed-wiring board of claim 50, in which the thermoplastic adhesive was bonded at a temperature between 0 and 200°C below a melting point of the perfluorocopolymer matrix.

52. The multilayer printed-wiring board of claim 51 , in which the thermoplastic adhesive was bonded at a temperature between 0 and 50°C below the melting point of the perfluorocopolymer matrix.

53. The multilayer printed-wiring board of claim 49, comprising a thermoset adhesive disposed between adjacent printed-wiring boards in the laminated structure.

54. The multilayer printed-wiring board of claim 53, in which the thermoset adhesive was cured at a temperature of between 150°C and 250°C.

55. The multilayer printed-wiring board of any of claims 49 to 54, in which a through-hole is defined through at least a portion of a thickness of the multilayer printed-wiring board; and comprising a copper film plating the through-hole.

56. An antenna usable with a 5G communications network, the antenna comprising: a printed-wiring board according to any of claims 49 to 55.

57. A method of making a multilayer printed-wiring board, the method comprising: providing multiple printed-wiring boards of claim 47; and laminating the multiple printed-wiring boards to form a multilayer laminated structure.

58. The method of claim 57, in which laminating the multiple printed-wiring boards comprises adhering adjacent printed-wiring boards using a thermoplastic prepreg.

59. The method of claim 58, comprising bonding the thermoplastic prepreg at a temperature between 0 and 100°C below a melting point of the adjacent perfluorocopolymer matrix.

60. The method of claim 59, comprising bonding the thermoplastic prepreg at a temperature between 0 and 50°C below the melting point of the adjacent perfluorocopolymer matrix.61 . The method of any of claims 57 to 60, comprising defining a through-hole through at least a portion of a thickness of the multilayer laminated structure.

62. The method of claim 61 , comprising defining the through-hole in an ultraviolet laser drilling process.

63. A method of making a laminate article, the method comprising: forming a layered article, the layered article comprising: first and second polymer films, each film comprising: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer, and an additive material capable of absorbing ultraviolet light, an L-glass fabric disposed between the first and second polymer films; and a conductive cladding disposed in contact with the first film; andapplying heat and pressure to the layered article to form the laminate article.

64. The method of claim 63, in which applying heat and pressure to the layered article comprises compressing the layered article in a heated platen.

65. The method of any of claims 63 to 64, in which applying heat and pressure to the layered article comprises processing the layered article in a roll-to-roll lamination process.

66. The method of any of claims 63 to 65, in which applying heat and pressure to the layered article comprises applying to the layered article a temperature between 10 and 80°C greater than a melting point of the perfluorocopolymer matrix.

67. The method of any of claims 63 to 66, in which applying heat and pressure to the layered article comprises applying to the layered article a temperature of between 250°C and 350°C.

68. The method of any of claims 63 to 67, in which applying heat and pressure to the layered article comprises applying to the layered article a pressure of between 50 psi and 1000 psi.

69. The method of any of claims 63 to ,68 comprising forming the first and second films in a melt processing and extrusion process.

70. The method of any of claims 63 to 69, comprising treating the L-glass fabric with a fluoropolymer treatment.71 . The method of claim 60, in which treating the L-glass fabric with a fluoropolymer treatment comprises coating the L-glass fabric with a fluoropolymer coating.

72. The method of claim 71 , in which coating the L-glass fabric with a fluoropolymer coating comprises coating the L-glass fabric in a solution coating process.

73. The method of claim 71 or 72, in which coating the L-glass fabric with a fluoropolymer coating comprises depositing fluoropolymer particles on a surface of the L-glass fabric.

74. A multilayer laminate comprising- a first layer comprising a dielectric substrate comprising: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; andan additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and,- a second layer comprising a dielectric substrate comprising: a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinated perfluorocopolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate.

75. The multilayer laminate of claim 74, where conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer.

76. A multilayer laminate comprising- a first layer comprising a dielectric substrate comprising: a perfluorocopolymer matrix comprising a fluorinated tetrafluoroethylene / hexafluoropropylene copolymer; an L-glass fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and,- a second layer comprising a dielectric substrate comprising:a perfluorocopolymer matrix comprising a fluorinated perfluorocopolymer and a non-fluorinated perfluorocopolymer; a quartz fabric embedded in the perfluorocopolymer matrix; and an additive material dispersed in the perfluorocopolymer matrix, in which the additive material is capable of absorbing ultraviolet light; and a conductive cladding disposed on a surface of the dielectric substrate.

77. The multilayer laminate of claim 76, where conductive cladding is disposed on multiple surfaces of the dielectric substrate of the second layer.

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