Composite material for manufacturing printed circuit boards, and manufacturing method

Abstract

The invention relates to a composite material for manufacturing printed circuit boards, offering advantages in terms of cost, weight, and availability compared to the conventionally used copper-clad laminate (CCL), the composite material comprising: - a planar carrier having a first and a second side, at least the two sides consisting of an electrically insulating material; - an aluminium foil which is integrally bonded to one of the two sides of the carrier; and - a solderable metal coating which is arranged exclusively on the side of the aluminium foil facing away from the carrier, contains copper or nickel or silver or gold, has a maximum layer thickness of 25 µm, and at least partially covers the aluminium foil. The invention also relates to a method for manufacturing the composite material.

Description

[0001]Composite material for the production of printed circuit boards and a production method. The invention relates to a composite material for the production of printed circuit boards and a method for its production. A printed circuit board is a carrier for electronic components. It serves for mechanical fastening and electrical connection. Printed circuit boards consist of electrically insulating material for a flat carrier with conductive connections (conductor tracks) adhered to it. Various materials can be used as insulating materials, such as fiber-reinforced plastic, laminated paper, epoxy resins, glass fibers, polytetrafluoroethylene, and polyimide. The conductor tracks are usually etched from a thin layer of copper, typically 35 µm. The components are soldered onto solder pads or pads.The precursor for the production of printed circuit boards prior to the step of etching the conductor tracks is a composite material comprising the flat substrate made of electrically insulating material with at least one metal layer bonded to one of the two sides of the substrate. Copper-clad laminate (CCL) is typically used as a precursor in the production process of printed circuit boards. A distinction is made between rigid and flexible copper-clad laminates. The copper layer enables the formation of conductor tracks, connection pads, and vias. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 1 von 28A via is a vertical electrical connection between the conductor track levels of a printed circuit board. The connection is usually made through an internally metallized passage through the substrate; it therefore requires a copper layer to be coated on both sides, overlapping at least in the area of ​​the via. The production of single- or double-sided copper-coated laminates for printed circuit board manufacturing typically involves lamination of copper foil to the substrate under heat and pressure. To create vias, holes are first drilled into the substrate. When the holes are metallized on the inner walls, the vias are created. Metallization of the holes requires nucleation, subsequent electroless deposition of a thin copper layer, and finally its electrolytic reinforcement.The subsequent production of the conductor tracks of a single- or multi-sided circuit board is usually carried out photolithographically, by applying a thin layer of light-sensitive photoresist to the surface of the still fully copper-coated laminate. After exposing the photoresist through a mask with the desired layout of the conductor tracks, depending on the photoresist used, either the exposed or unexposed portions of the resist are soluble in a developer solution and are removed. If the pretreated circuit board is placed in a suitable etching solution, e.g., dissolved in water, the resulting etching effect is reduced. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 2 von 28Iron(III) chloride or sodium persulfate, only the exposed part of the metallized surface is attacked; the areas covered by photoresist remain intact because the resist is resistant to the etching solution. Solder mask can then be applied to protect the conductor tracks, covering the conductor tracks and leaving only the soldering pads exposed. If SMD components are to be soldered, solder paste is applied to the connection pads using a solder paste mask. Furthermore, the SMD components can be fixed until soldering by applying adhesive dots. US 20230054257 A1 discloses a copper-clad laminate as a composite material comprising a carrier made of insulating material. The carrier contains a resin composition with a specific polymer to produce a printed circuit board from the composite material with a high signal transmission rate and thermal capacity.Based on this prior art, the invention is based on the object of proposing a composite material for the production of printed circuit boards that offers advantages in terms of cost, weight, and availability compared to the commonly used copper-clad laminate (CCL). Furthermore, a method for its production is to be proposed. This object is achieved by a composite material having the features of independent claim 1 and a method for producing the same. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 3 von 28The problem addressed by the composite material for producing printed circuit boards is solved with the features of independent claim 16. The composite material for producing printed circuit boards comprises a flat carrier with a first and a second side, wherein at least both sides are made of an electrically insulating material. The flat carrier can be rigid or flexible, depending on the requirements of the printed circuit board to be produced. The flat, rigid carrier can in particular be made of the materials FR4, CEM1, CEM3, or PTFE: ^FR4 refers to a class of flame-retardant composite materials consisting of epoxy resin and glass fiber fabric. ^CEM materials are a cost-effective alternative that are qualitatively inferior to FR4 materials, since these materials do not consist entirely of glass fiber fabric. CEM-1 has a core made of epoxy resin-impregnated paper with an outer layer of glass fiber fabric.CEM-3 has a core made of random glass fibers impregnated with epoxy resin and also has a glass fiber fabric outer layer. Polytetrafluoroethylene (PTFE) is an unbranched, linear, semi-crystalline polymer made of fluorine and carbon. PTFE circuit boards are used in high-frequency and / or high-temperature applications. PTFE Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 4 von 28Printed circuit boards have very good mechanical, thermal, and electrical properties. For high-performance electronic circuits with high heat generation, the flat, rigid substrate can have a metal core made of an electrically insulating material between its two sides. For example, the substrate can be designed as an IMS substrate with an aluminum core (IMS abbreviation for "Insulated Metal Substrate"), whereby the aluminum core distributes the localized heat at so-called "hot spots" across the entire circuit board. Heat buildup on the components of the assembled circuit board is avoided. Finally, if the expected thermal load on the circuit board to be manufactured is very high, the flat, rigid substrate can be made of ceramic materials such as aluminum oxide and aluminum nitride. The rigid substrate preferably has a thickness of 0.5 - 2 mm.A flat, flexible carrier can be designed, in particular, as a film, preferably made of polyimide (abbreviated to PI), polyethylene terephthalate (abbreviated to PET), polycarbonate (abbreviated to PC), or polypropylene (abbreviated to PP). The flexible carrier preferably has a thickness of 10–200 µm. According to the invention, an aluminum foil is integrally bonded to at least one of the two sides of the carrier to produce a single-layer printed circuit board. Regarding production, patent attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 5 von 28In double-sided printed circuit boards that can be populated on both sides, both sides of the carrier are bonded to an aluminum foil. The bonding is achieved by lamination, whereby the term encompasses both a thermal bonding of the aluminum foil to the carrier exclusively through pressure and temperature, as well as the bonding of the aluminum foil to the carrier using an adhesive. Each aluminum foil covers one of the two sides of the carrier at least partially, but preferably completely. Each aluminum foil has a thickness of 1 µm - 500 µm, preferably a thickness of 50 µm - 55 µm. In terms of electrical conductivity, the preferred thickness of 50 µm - 55 µm corresponds to the standard of a 35 µm thick copper layer of a copper-clad laminate according to the state of the art. The aluminum foils for forming the conductor tracks are preferably made of aluminum alloys from groups 1xxx and 8xxx.Preferred aluminum alloys from group 1xxx are aluminum alloys of types 1100, 1200, and 1235. Preferred aluminum alloys from group 8xxx are aluminum alloys of types 8011 and 8089. However, aluminum alloys from groups 3XXX and 6XXX can also be considered for the formation of the conductor tracks. In the context of the invention, the term "aluminum foil" includes foils made of pure aluminum (group 1xxx) with at least 99% aluminum, as well as foils made of aluminum alloys from other groups with other alloying elements. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 6 von 28To improve adhesion to the surface of the carrier, each aluminum foil can have a roughened surface on the side facing the carrier. According to the invention, a solderable metallic coating containing copper, nickel, silver, or gold with a maximum layer thickness of 25 µm, preferably a maximum of 10 µm, is applied to the side of each aluminum foil facing away from the carrier, which coating at least partially covers the aluminum foil. The metallic coating contains the metals copper, nickel, silver, or gold as its main component, i.e., the aforementioned metals make up at least 90 percent by weight of the mass of the alloy forming the metallic coating. However, the metallic coating can also consist entirely of the aforementioned metals. The printed circuit board to be produced from the composite material must have a solderable metallic surface at least at the connection surfaces.For this reason, each aluminum foil has a metallic coating on the side facing away from the carrier. A copper- or nickel-containing metallic coating provides a solderable surface with good adhesion for solder connections to electrical components or SMD parts. Metallic coatings made of gold or silver can also be considered for producing solderable metallic surfaces. The exclusively one-sided metallic coating of each aluminum foil on the side facing away from the carrier is patent attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 7 von 28This is necessary because a metallic coating applied directly to the substrate could not be removed in a subsequent etching process for producing the circuit board's conductor track structure, resulting in short circuits between the conductor tracks. For the deposition of the solderable metallic coating containing copper, nickel, gold, or silver on the aluminum foil, the zincate process, for example, can be used for surface pretreatment. The so-called zincate process for metal coating aluminum is described in "Information Sheet O8 - 2nd Edition, Galvanic and Chemical Coatings, German Association of the Aluminum Industry" (GDAC). The surface pretreatment required for metal coating aluminum comprises several steps: cleaning and degreasing, pickling, and activation. Cleaning serves to remove dirt and grease residues from the surface of the aluminum workpiece.The subsequent alkaline pickling removes the aluminum oxide layer. A subsequent pickling with an acidic solution removes any heavy metal particles that have not been detached from the surface of the workpiece, which are present as alloy components. Subsequent activation with a zincate treatment prevents renewed surface oxidation. For this purpose, the surface is rinsed at least once with a zincate pickling solution. Zinc from the solution precipitates. Alternatively, it is possible to create a solderable metallic coating without pretreating the aluminum foil, exclusively on the side of the aluminum foil facing away from the carrier. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 8 von 28The coating is rolled or rolled onto a copper foil. When the copper foil is mechanically pressed onto the surface, the oxide layer on the aluminum foil is destroyed, and a metallurgical bond between the copper and aluminum is formed by the contact pressure and the flow of the surfaces. The metallic coating can also be deposited on one side of the aluminum foil using an atmospheric plasma process. The metallic coating can also be applied by physical vapor deposition (PVD) or by rolling on a thin metal foil, whereby the rolled-on metal foil mechanically interlocks with the underlying aluminum foil.If the metallic coating of the aluminum foil is applied chemically or electrochemically in an immersion bath, it is necessary to provide one side of the aluminum foil with a removable protective film prior to coating the aluminum foil. This protective film is removed again prior to the step of laminating the coated aluminum foil to the carrier. According to the invention, the one-sided, solderable metallic coating on the side of the aluminum foil facing away from the carrier has a maximum layer thickness of 25 µm, preferably a maximum of 10 µm. This limitation of the maximum layer thickness ensures that the metallic coating is sufficiently etched during the subsequent etching process of the aluminum foil to form the conductor track structure, as far as patent attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 9 von 28If the layer thickness is greater, the etchant may no longer be able to remove the solderable metallic coating, and short circuits could occur. The solderable metallic coating preferably has a thickness of 1 µm - 5 µm, particularly preferably a thickness of 2 µm - 3 µm. In one embodiment of the invention, a barrier layer with a maximum layer thickness of 1 µm is arranged between the solderable metallic coating and the aluminum foil in order to prevent electrocorrosion between the adjacent metallic layers. The barrier layer contains nickel, palladium, or zinc and is applied to the surface of the aluminum foil. For the production of double-sided printed circuit boards with vias, it is necessary that the metallic coatings of the aluminum foils overlap at least partially on both sides of the carrier.This requirement is always met with the preferred manufacturing process for the composite material with a complete metallic coating of the aluminum foil on both sides of the carrier. The vias connect the overlapping areas of the metallic coatings on the top and bottom of the composite material to electrically connect the conductor track levels located on both sides of the printed circuit board to be manufactured. To produce a via, the composite material must have passages between the overlapping areas to form the vias. The passages are perpendicular to the surface. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 10 von 28of the carrier, in particular by means of a bore, into the carrier and the metal-coated aluminum layers on both sides of the carrier. In order to selectively metallize the vias by means of galvanic deposition only on the inner walls of the vias, in particular with copper, but to prevent a further increase in the layer thickness of the previously applied metallic coating on the two aluminum foils of the composite material for producing a double-sided printed circuit board, the aluminum foils, including the metallic coatings, on both sides of the carrier are each provided with a removable mask in order to effect the selective metallization of the vias by means of galvanic deposition exclusively in the vias of the composite material.The removable masking can be, for example, a lacquer, in particular a photoresist or a plastic film, which is not attacked during metallization by means of electroplating. In an advantageous embodiment of the invention, the masking surrounds the passage in a ring shape at a distance from the edge of the passage, so that the metallization is deposited not only on the inner wall of the passage, but also on the ring-shaped area surrounding the passage on the surface of the metallic coating. The ring-shaped area has, for example, a constant width of 20-100 µm. The ring-shaped, unmasked area improves the electrical connection of the via to the metallic coating. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 11 von 28Both sides of the carrier. The metallization of the vias preferably has a thickness of up to 25 µm. To improve the adhesion of the metallization in the vias, the vias can be provided with an adhesion promoter before metallization. Palladium can be used as an adhesion promoter because of its high affinity for plastics and its good adhesion properties. The nucleation of the vias with palladium can be carried out by chemical deposition, electrodeposition, or plasma coating. Alternatively, carbon inks can be considered as adhesion promoters. Carbon ink typically contains between 3 and 5 wt.% suspended carbon particles in the range of 10 nm to 1000 nm. The invention is explained in more detail below with reference to the figures. Patent attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 12 von 28Fig. 1 shows a composite material according to the invention for producing a single-sided printed circuit board. Fig. 2 shows a composite material for producing a double-sided printed circuit board. Fig. 3 a)-g) shows the introduction of a via into a composite material for a double-sided printed circuit board. Fig. 4a), 4b) shows the composite material according to Fig. 3a), b) in plan view. Fig. 5a) shows a schematic representation of the production of a single-sided printed circuit board from the composite material according to the invention. Fig. 6 shows a schematic representation of the production of a single-sided printed circuit board from a defective composite material with a solderable metallic coating that is too thick. Fig. 1 shows a section through a composite material 1 according to the invention for producing a single-sided printed circuit board, comprising a flat carrier 2, which in the illustrated embodiment is a rigid carrier made of one of the common electrically insulating materials, such as FR4, CEM1 or CEM3.The flat carrier 2 has two parallel, flat sides 2.1, 2.2, with the first side 2.1 in the figure being fully bonded to an aluminum foil 3. The bonding is achieved by lamination, with the lamination involving both a thermal bonding of the aluminum foil 3 to the carrier 2. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 13 von 28exclusively under pressure and temperature as well as the bonding of the aluminum foil 3 to the carrier 2 by means of an adhesive. On the side of the aluminum foil 3 facing away from the carrier 2, i.e. on its upper side in the image, a solderable metallic coating 4 is arranged. In the illustrated embodiment, the solderable metallic coating 4 covers the aluminum foil 3 completely. In principle, however, it is also conceivable for the solderable metallic coating 4 to only partially cover the aluminum foil 3 in the areas in which the circuit board to be produced has connection surfaces for components and / or wiring. The aluminum foil 3 has a preferred thickness of approximately 50 µm to 55 µm. In terms of electrical conductivity, this thickness corresponds to the standard of a 35 µm thick copper layer of a copper-coated laminate for producing a circuit board.The solderable metallic coating 4 contains copper, nickel, silver, or gold as its main component and has a maximum layer thickness of 25 µm, preferably 10 µm. Limiting the maximum layer thickness of the solderable metallic coating 4 ensures that the metallic coating is removed, if necessary, during the subsequent etching process of the aluminum foil 3 to produce the conductor track structure, as will be explained in more detail later with reference to Figures 5a), 5b), and 6. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 14 von 28In the embodiment shown in Figure 1, a barrier layer 5 is arranged between the solderable metallic coating 4 and the aluminum foil 3 to prevent electrocorrosion between adjacent metallic layers. The barrier layer 5 contains nickel, palladium, or zinc and is applied to the surface of the aluminum layer 3 facing upwards in Figure 1. Figure 2 shows a composite material 6 for producing a double-sided printed circuit board. Where the composite material 6 has matching layers, the same reference numerals are used as for the composite material 1 shown in Figure 1. In the composite material 6 for producing double-sided printed circuit boards that can be equipped with electronic / electrical components on both sides, both sides 2.1, 2.2 of the carrier 2 are each bonded to an aluminum foil 3. The bonding is effected in the same way as for the composite material 1.The solderable metallic coatings 4 of the aluminum foils 3 on both sides 2.1, 2.2 of the carrier 2 overlap completely on both sides of the carrier 2. Depending on the arrangement of any vias 7 between the conductor track levels on both sides 2.1, 2.2 of the carrier 2, however, it may also be sufficient for the solderable metallic coatings 4 on both sides of 2.1, 2.2 of the carrier 2 to overlap only partially. A barrier layer 5 is arranged between the solderable metallic coating 4 and the aluminum foil 3 on both sides 2.1, 2.2 of the carrier 2. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 15 von 28The thickness of the aluminum foils 3 and the solderable metallic coatings 4 correspond in thickness to the corresponding layers / ply of the composite material 1. Fig. 3 illustrates the process of introducing a via 7 into a composite material 8. Fig. 3a) shows, as a starting point, a composite material 8 for producing a double-sided printed circuit board, which corresponds in structure to the composite material 6 according to Fig. 2, but has no barrier layer 5 on both sides 2.1, 2.2 of the carrier 2 between the solderable metallic coating 4 and the aluminum foil 3. The solderable metallic coatings 4 and the aluminum foils 3 on both sides of the carrier 2 completely overlap.The through-plating 7 to be introduced connects the overlapping areas of the metallic coatings 4 on the top and bottom sides of the composite material 8 in order to electrically connect the conductor track levels located on both sides of the circuit board to be produced. To produce a through-plating 7, it is necessary that a through-plating 9 is introduced into the composite material 8, in particular by way of a bore 10, as shown in Figure 3b). The through-plating 9 penetrates the carrier 2 and the aluminum layers 3, each provided with the solderable metallic coating 4, on both sides 2.1, 2.2 of the carrier 2. In order to selectively metallize the through-plating 9 with copper by means of galvanic deposition only on the inner walls of the through-plating 9, but to further increase the layer thickness of the previously applied solderable coating, Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p.eite 16 von 28To prevent the metallic coating 4 on the two aluminum foils 3 of the composite material 8 from sticking out, the two aluminum foils 3, including the solderable metallic coating 4, are each provided on both sides of the carrier 2 with a removable masking 11, for example in the form of a removable plastic film. A current source 12 is connected to the solderable metallic coating 4 on both sides of the carrier 2 of the masked composite material 8 in order to electrochemically deposit copper on the inner wall of the passage 9. The metallic deposits of the copper form a metallization 13 exclusively in the passage 9, as can be seen in Fig. 3c). The metallization 13 is electrically conductively connected to the aluminum foil 3 and the conductive metallic coating 4 deposited thereon on both sides 2.1, 2.2 of the carrier 2.After the electrochemical deposition of copper in the via 9 and thus the production of the through-hole connection 7, the masking 11 is removed. Fig. 3d) shows the composite material 8 with a through-hole connection 7 after the removal of the masking 11. Fig. 4a) shows the composite material 8 according to Fig. 3a) in a top view of the masking 11, while Fig. 4b) shows a top view of the masking 11 of the composite material 8 after the holes for the through-holes 9 have been drilled. Figures 3e), 3f) and 3g) show a composite material 8 for producing a double-sided printed circuit board, wherein for the sake of clarity the metallic coating 4 is only shown on one side of the carrier 2. Patent attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 17 von 28The masking 11 surrounds each passage 9 in a ring shape at a short distance from the circumferential edge 19 of the passage 9. The masking can be applied in the form of a PET film or photolithographically before the passages 9 are introduced. The annular, unmasked region 18 of the metallic coating 4 surrounding each passage causes the metallization 13 to be selectively deposited not only on the inner wall of the passage 9, but also on the annular region 18 on the surface of the metallic coating 4, as shown in Figures 3f) and 3g). Figure 3f) shows the composite material 8 with via 7 after the masking 11 has been removed. Fig. 5a), b) illustrates the production of a single-sided printed circuit board from a composite material 1. The production of the conductor tracks 16 including the connection areas is carried out photolithographically, in which a photomask 14 is applied to the surface of the composite material 1, iethe solderable metallic coating 4 is applied. As can be seen from Fig. 5a), the carrier 2 is completely covered with the aluminum foil 3 and the solderable metallic coating 4. The composite material 1 provided with the photomask 14 is introduced into a suitable etching solution 15, for example, iron(III) chloride dissolved in water, and attacks the part of the solderable metallized coating 4 exposed by the mask 14 and subsequently the aluminum foil 3, completely removing these two layers, as can be seen in Fig. 5b). The two conductor tracks 16 remain. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 p. eite 18 von 28on the carrier 2, whose solderable metallic coatings 4 are electrically separated from one another. By limiting the maximum layer thickness of the solderable metallic coating 4, it is ensured that the metallic coating 4 is also removed, if necessary, during the etching process of the aluminum foil 3 to form the conductor tracks 16. Fig. 6, however, shows the case in which the maximum layer thickness of the solderable metallic coating 4 of 25 µm, limited according to the invention, was exceeded. It can be seen that the etching solution could not sufficiently remove either the metallic coating 4 or the aluminum foil 3. The unremoved webs 17 of the aluminum foil 3 lead to a short circuit between the conductor tracks 16 to be produced. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 19 von 28 List of reference symbols Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 20 von 28

Claims

Patent claims:

1. Verbundmaterial (1,6,8) zur Herstellung von Leiterplatten comprehensive - einen flächigen Träger (2) mit einer ersten und einer zweiten Seite (2.1, 2.2), wobei zumindest die beiden Seiten (2.1, 2.2) aus einem elektrischen isolierendem material, - eine Aluminiumfolie (3), die mit einer der beiden Seiten (2.1, 2.2) des Trägers (2) stoffschlüssig is connected, - eine ausschließlich auf der vom Träger (2) abgewandten Seite der Aluminiumfolie (3) angeordnete lötfähige metallische Beschichtung (4) enthaltend Kupfer oder Nickel oder Silber oder Gold mit einer maximalen Schichtdicke von 25 µm, die die Aluminiumfolie (3) zumindest teilweise bedeckt.

2. Verbundmaterial nach Anspruch 1, dadurch gekennzeichnet, dass beide Seiten (2.1, 2.2) des Trägers (2) mit jeweils einer Aluminiumfolie (3) stoffschlüssig verbunden sind.

3. Verbundmaterial nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass jede Aluminiumfolie (3) eine der beiden Seiten (2.1,2.2) des Trägers (2) zumindest partially covered. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 21 von 28 4. Verbundmaterial nach Anspruch 2 und 3, dadurch characterized in that the metallic coatings ( 4) der Aluminiumfolien (3) auf beiden Seiten (2.1, 2.2) des Trägers (2) zumindest in Bereichen überlappen.

5. Verbundmaterial nach Anspruch 4, dadurch gekennzeichnet , dass zwischen den überlappenden Bereichen Durchgänge (9) zur Ausbildung von Durchkontaktierungen (7) zwischen den metallischen Beschichtungen (4) angeordnet sind.

6. Verbundmaterial nach Anspruch 5, dadurch gekennzeichnet, dass die Aluminiumfolien (3) einschließlich der metallischen Beschichtungen (4) auf beiden Seiten (2.1, 2.2) des Trägers (2) jeweils mit einer wieder ablösbaren Maskierung (11) versehen sind, eingerichtet um eine selektive Metallisierung (13) der Durchgänge (9) zu make possible.

7. Verbundmaterial nach Anspruch 6, dadurch gekennzeichnet, dass die Maskierung (11) jeden Durchgang (9) ringförmig in einem Abstand zu dem Rand (19) des Durchgangs (9) in such a way that the metallization is selectively deposited not only on the inner wall of the passage (9), but also in an annular region (18) surrounding the passage on the surface of the metallic B eschichtung (4) auf beiden Seiten (2.1, 2.2) des Trägers(2) is separated. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 22 von 28 8. Verbundmaterial nach einem der Ansprüche 5 bis 7, dadurch gekennzeichnet, dass die Durchgänge (9) mit einem Keimbildner beschichtet sind.

9. Verbundmaterial nach einem der Ansprüche 1 bis 8, characterized in that the solderable metallic B eschichtung (4) jeder Aluminiumfolie (3) Kupfer oder Contains nickel or silver or gold as the main component, which constitutes at least 90% by weight of the mass of the metallic coating.

10. Verbundmaterial nach einem der Ansprüche 1 bis 9, characterized in that between the solderable m etallischen Beschichtung (4) und der Aluminiumfolie (3) eine Barriereschicht (5) angeordnet ist.

11. Verbundmaterial nach einem der Ansprüche 1 bis 10, dadurch gekennzeichnet, dass jede lötfähige metallische Beschichtung (4) eine Dicke von 1µm - 5µm aufweist.

12. Verbundmaterial nach einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, dass jede Aluminiumfolie (3) eine Dicke von 1µm - 500µm aufweist, vorzugsweise eine Dicke von 50µm - 55µm.

13. Verbundmaterial nach einem der Ansprüche 1 bis 12, dadurch gekennzeichnet, dass jede Aluminiumfolie aus einer Aluminiumlegierung der nachfolgenden Gruppen exists: 1XXX, 3XXX, 6XXX, 8XXX. Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Mandanten\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 23 von 28 14. Verbundmaterial nach einem der Ansprüche 1 bis 13, dadurch gekennzeichnet, dass der flächige Träger (2) starr ist und aus FR4, CEM1, CEM3 oder PTFE besteht.

15. Verbundmaterial nach einem der Ansprüche 1 bis 13, dadurch gekennzeichnet, dass der flächige Träger (2) starr ist und zwischen dessen beiden Seiten (2.1, 2.2) a metal core is arranged from an electrically insulating material.

16. Verbundmaterial nach einem der Ansprüche 1 bis 13, dadurch gekennzeichnet, dass der flächige Träger (2) flexibel ist und aus einer Folie aus PI, PET, PC oder PP consists.

17. Verfahren zur Herstellung eines Verbundmaterials (1) nach Anspruch 1 gekennzeichnet durch folgende Schritte:- Bereitstellen eines flächigen Trägers (2) mit einer ersten und einer zweiten Seite (2.1, 2.2), wobei zumindest die beiden Seiten (2.1, 2.2) aus einem electrically insulating material, - einseitiges Beschichten ausschließlich einer Seite der Aluminiumfolie (3) mit einer lötfähigen metallischen Beschichtung (4) enthaltend Kupfer oder Nickel or silver or gold with a maximum S chichtdicke von 25 µm, die die Aluminiumfolie (3) at least partially covered, - Laminieren der Aluminiumfolie (3) auf eine der beiden Seiten (2.1, 2.2) des Trägers (2) zur Herstellung Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Clients\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 24 von 28 a material connection between the carrier ( 2) und der Aluminiumfolie (3), wobei sich die metallische Beschichtung (4) auf der vom Träger (2) abgewandten Seite der Aluminiumfolie (3) befindet.

18. Verfahren zur Herstellung eines Verbundmaterials nach Anspruch 17, gekennzeichnet durch die weiteren Schritte - Abdecken einer Seite der Aluminiumfolie (3) mit einer removable protective film before the one-sided B eschichten, wobei das einseitige Beschichten only the other side of the aluminum foil m it der lötfähigen metallischen Beschichtung (4) chemically or electrochemically in an immersion bath, - Ablösen der Schutzfolie von der Aluminiumfolie (3) after the one-sided coating step and before the lamination step.

19. Verfahren zur Herstellung eines Verbundmaterials nach Anspruch 17 oder 18, dadurch gekennzeichnet, dass - auf beide Seiten (2.1, 2.2) des Trägers (2) jeweils eine Aluminiumfolie (3) laminiert wird, wobei sich die metallischen Beschichtungen (4) der beiden Aluminiumfolien (3) auf beiden Seiten (2.1, 2.2) des Trägers (2) zumindest in Bereichen überlappen, - die Aluminiumfolien (3) einschließlich der metallischen Beschichtungen (4) auf beiden SeitenPatent Attorney Dipl.-Ing. Kai Kohlmann S:\Clients\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 25 von 28 (2.1, 2.2) des Trägers (2) jeweils derart maskiert werden, dass die Maskierung (11) wieder ablösbar ist, - Durchgänge (9) zur Ausbildung von Durchkontaktierungen (7) zwischen den überlappenden Bereichen der metallischen Beschichtungen (4) in das Verbundmaterial (8) eingebracht werden und - nach dem Maskieren und Einbringen der Durchgänge (9) the passages of the composite material are metallized.

20. Verfahren zur Herstellung eines Verbundmaterials nach Claim 19, characterized in that before step d es Metallisierens die Durchgänge (9) mit einem Keimbildner beschichtet werden.

21. Verfahren zur Herstellung eines Verbundmaterials nach Anspruch 19 oder 20, dadurch gekennzeichnet, dass zur Metallisierung Kupfer in den Durchgängen (9) galvanisch is separated.

22. Verfahren zur Herstellung eines Verbundmaterials nach einem der Ansprüche 19 bis 21, dadurch gekennzeichnet, that - die Aluminiumfolien (3) einschließlich der metallischen Beschichtungen (4) auf beiden Seiten (2.1, 2.2) des Trägers (2) jeweils derart maskiert werden, dass die Maskierung (11) jeden Durchgang (9) ringförmig in einem Abstand zu dem Rand (19) des Durchgangs (9) umgibt und Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Clients\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 26 von 28 - nach dem Maskieren und Einbringen der Durchgänge (9) die Durchgänge und die jeden Durchgang (9) umgebenden Areas (18) on the surface of the metallic B eschichtung (4) auf beiden Seiten (2.1, 2.2) des Trägers (2) metallisiert werden.

23. Verfahren zur Herstellung eines Verbundmaterials (1) nach one of claims 17 to 22, characterized in that ass vor dem Schritt des einseitigen Beschichtens der Aluminum foil (3) a surface pretreatment by means of d es Zinkatverfahrens durchgeführt wird.Patent Attorney Dipl.-Ing. Kai Kohlmann S:\Clients\Plasma Innovations\23067-02\anm 01.docx December 20, 2024 S eite 27 von 28

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