Metal foil carrier, strippable metal foil and circuit board

Abstract

The utility model discloses a metal foil carrier, a strippable metal foil and a circuit board, the metal foil carrier comprises a supporting layer, the supporting layer is provided with a first side surface used for being connected with a functional layer, and the density of the supporting layer is smaller than that of metal. According to the metal foil carrier, the strippable metal foil and the circuit board disclosed by the utility model, the density of the supporting layer in the metal foil carrier is smaller than that of metal, so that the consumption of the metal can be greatly reduced under the condition of the same thickness, and the material waste caused by stripping of the metal foil carrier is further reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of metal foils, in particular to a metal foil carrier, a peelable metal foil and a circuit board. Background Art

[0002] With the booming development of the PCB industry, electrolytic metal foil, as a key material for high-frequency and high-speed printed circuit boards for 5G communication, plays an increasingly important role in both the raw material copper clad laminate and the manufacturing process of PCB. Ultra-thin metal foil is an important development direction of electrolytic metal foil. At present, the thickness of electrolytic metal foil is gradually developing towards 12μm, 9μm, 5μm, or even thinner. However, due to the low mechanical strength of ultra-thin metal foil, it is difficult to completely peel it from the cathode roller during preparation, and it is prone to phenomena such as curling, wrinkling or tearing during transportation, thus affecting subsequent applications. Currently, a preparation technology for ultra-thin metal foil with a carrier has been proposed. Due to the support of the carrier, the mechanical strength of ultra-thin metal foil can be improved.

[0003] The peelable metal foil with a carrier is widely used for laminating with a substrate through hot pressing, and then the metal foil layer is peeled from the carrier layer for use as a copper clad laminate. However, in terms of use, the thickness of the metal foil layer is one fraction to one fortieth of that of the carrier layer, and serious material waste will be caused after the carrier layer is peeled off. Summary of the Utility Model

[0004] The utility model provides a metal foil carrier, a peelable metal foil and a circuit board. By making the density of the support layer in the metal foil carrier less than the density of the metal, the process requirements can be ensured under the same thickness, and the amount of metal used can be greatly reduced, thereby reducing the material waste caused after the metal foil carrier is peeled off.

[0005] To solve the above technical problems, in the first aspect of the embodiments of the utility model, a metal foil carrier is provided. The metal foil carrier includes a support layer, the support layer is provided with a first side surface for connecting with a functional layer, and the density of the support layer is less than the density of the metal.

[0006] As a preferred solution, the support layer includes an organic layer or an inorganic layer; or, the support layer includes at least two layers, and at least two layers include an organic layer and / or an inorganic layer.

[0007] As a preferred solution, the metal foil carrier further includes a first conductive layer, and the first conductive layer is disposed on the first side surface.

[0008] As a preferred solution, the metal foil carrier further includes a heat-resistant layer. The support layer is further provided with a second side surface, the heat-resistant layer is disposed on the second side surface, and the first side surface and the second side surface are respectively disposed on opposite sides of the support layer.

[0009] As a preferred solution, the heat-resistant layer is a polyether ether ketone film.

[0010] As a preferred solution, the metal foil carrier further includes a second conductive layer, and the second conductive layer is disposed between the heat-resistant layer and the support layer.

[0011] As a preferred solution, the bonding strength between the heat-resistant layer and the second conductive layer is greater than 0.6 N / cm.

[0012] As a preferred solution, the bonding strength between the first conductive layer and the support layer is greater than 0.6 N / cm.

[0013] As a preferred solution, the bonding strength between the second conductive layer and the support layer is greater than 0.6 N / cm.

[0014] As a preferred solution, the support layer is provided with through holes, and the first conductive layer is electrically connected to the second conductive layer through the through holes.

[0015] As a preferred solution, the diameter of the through hole increases first and then decreases from the first conductive layer to the second conductive layer.

[0016] As a preferred solution, the difference between the axial distance of two adjacent through holes and the maximum aperture of the through hole is greater than 9 μm.

[0017] As a preferred solution, the difference in the coefficient of thermal expansion between the first conductive layer and the support layer is less than 15 PPM / °C.

[0018] As a preferred solution, the difference in the coefficient of thermal expansion between the second conductive layer and the support layer is less than 15 PPM / °C.

[0019] As a preferred solution, the thickness of the heat-resistant layer is 20 nm to 15 μm.

[0020] As a preferred solution, the thickness of the support layer is 10 μm to 100 μm.

[0021] In the second aspect of the embodiments of the present invention, a peelable metal foil is provided. The peelable metal foil includes a functional layer, a release layer, and the metal foil carrier according to any one of the first aspect. The functional layer is connected to the first side surface of the support layer in the metal foil carrier through the release layer.

[0022] In the third aspect of the embodiments of the present invention, a circuit board is provided. The circuit board includes the peelable metal foil according to the second aspect.

[0023] Compared with the prior art, the beneficial effect of the embodiment of the present utility model is that, since the density of the support layer in the metal foil carrier is less than the density of the metal, the process requirements can be ensured under the same thickness, and the amount of metal used can be greatly reduced, thereby reducing the material waste caused by the peeling of the metal foil carrier. Brief Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the first metal foil carrier provided by the embodiment of the present utility model;

[0025] Figure 2 is a schematic structural diagram of the second metal foil carrier provided by the embodiment of the present utility model;

[0026] Figure 3 is a schematic structural diagram of the third metal foil carrier provided by the embodiment of the present utility model;

[0027] Figure 4 is a schematic structural diagram of the fourth metal foil carrier provided by the embodiment of the present utility model;

[0028] Figure 5 is a schematic structural diagram of the peelable metal foil in the embodiment of the present utility model;

[0029] Wherein, 100, metal foil carrier; 101, support layer; 102, first conductive layer; 103, heat-resistant layer; 104, second conductive layer; 200, peeling layer; 300, functional layer. Detailed Embodiments

[0030] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. The purpose of providing these embodiments is to make the disclosure of the present utility model more thorough and comprehensive. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0031] In the description of the present application, the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0032] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for the purpose of illustration, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0033] In the description of the present application, it should be noted that unless otherwise defined, all technical and scientific terms used in the present utility model have the same meanings as those commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used in the specification of the present utility model are only for the purpose of describing specific embodiments, and are not intended to limit the present utility model. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] Please refer to Figure 1 , Figure 1 FIG. 10 is a schematic structural view of a first metal foil carrier provided by an embodiment of the present utility model. In a first aspect of the embodiment of the present utility model, a metal foil carrier 100 is provided. The metal foil carrier 100 includes a support layer 101. The support layer 101 is provided with a first side surface for connecting with a functional layer 300, and the density of the support layer 101 is less than the density of the metal.

[0035] It is worth noting that the metal foil carrier 100 is stacked with other material layers such as the functional layer 300 in the metal foil during actual application, and is used to carry and protect the material layer, so that the material layer is not damaged by external contact or collision, etc., or to meet the requirements of more refined circuit manufacturing processes. After the functional layer 300 is hot-pressed onto the circuit board, the metal foil carrier 100 needs to be peeled off.

[0036] In this embodiment, the metal foil carrier 100 includes a support layer 101. The support layer 101 has a first side for connecting with the functional layer 300. For example, the functional layer 300 is stacked on the first side of the support layer 101. It should be noted that the support layer 101 can provide support strength for the functional layer 300, playing a stable support role to avoid phenomena such as curling, wrinkling or tearing of the peelable metal foil during transportation. Further, the density of the support layer 101 is less than the density of the metal. Thus, compared with the traditional metal carrier layer, under the same thickness of the metal foil carrier 100, the amount of metal used can be greatly reduced, thereby reducing the material waste caused after the peeling of the metal foil carrier 100, effectively reducing the use and recycling costs, and meeting the environmental protection requirements. Taking the ultra-thin peelable copper foil as an example, in this embodiment, the metal foil carrier 100 as the carrier of the ultra-thin peelable copper foil has a support layer 101 with a density less than that of copper. Thus, compared with the traditional copper carrier layer, under the same thickness of the metal foil carrier 100, the amount of copper used can be significantly reduced, thereby reducing the waste of metal.

[0037] In the metal foil carrier 100 provided by the embodiment of the present utility model, since the density of the support layer 101 in the metal foil carrier 100 is less than the density of the metal, the amount of metal used can be greatly reduced under the same thickness, and further the material waste caused after the peeling of the metal foil carrier 100 can be reduced.

[0038] As a preferred solution, the support layer 101 includes an organic layer or an inorganic layer; or, the support layer 101 includes at least two layers, and at least two layers include an organic layer and / or an inorganic layer.

[0039] Specifically, in this embodiment, the number of layers of the support layer 101 can be a single layer, or two or more layers. When the support layer 101 is a single layer, the support layer 101 is formed by one organic layer or inorganic layer. Exemplarily, the material of the organic layer can be specifically selected from organic polymer materials, including at least one of polyethylene terephthalate, polyether ether ketone, polyetherimide, polycarbonate, polymethyl methacrylate, polypropylene, polyimide, polyamide, and polyoxymethylene, but not limited thereto. Other organic materials disclosed in the prior art can also be used as the material of the organic layer to form the support layer 101; the material of the inorganic layer can be specifically selected from metal materials, including one of aluminum, magnesium, titanium, lead, and zinc or an alloy of one of them, but not limited thereto. Other inorganic materials disclosed in the prior art can also be used as the material of the inorganic layer to form the support layer 101. When the support layer 101 is two or more layers, the support layer 101 can be formed by laminating two or more layers of the same organic layer, or by laminating two or more layers of different organic layers, or by laminating two or more layers of the same inorganic layer, or by laminating two or more layers of different inorganic layers, or by laminating organic layers and inorganic layers to form two or more layers of the support layer 101. This embodiment does not make specific limitations here.

[0040] In the embodiment of the present utility model, by using an organic layer and / or an inorganic layer to form the support layer 101 of the metal foil carrier 100, and setting the number of layers of the support layer 101 to one layer, two layers or more than two layers, the support strength can be provided for the functional layer 300, and a stable support effect can be achieved.

[0041] As a preferred solution, the support layer 101 is composed of at least one organic layer, and the organic layer includes at least one organic polymer material of polyethylene terephthalate, polyether ether ketone, polyetherimide, polycarbonate, polymethyl methacrylate, polypropylene, polyimide, polyamide, and polyoxymethylene.

[0042] Specifically, in this embodiment, an organic polymer layer is preferably used to form the support layer 101. Compared with the traditional metal carrier layer, the use of metal materials can be further reduced. When the metal foil carrier 100 is peeled off and enters the recycling process, the impurities after pickling will not affect the quality of copper ions, which is convenient for rapid separation of impurities. The use and recycling costs are lower, and the organic polymer material has the advantages of light weight, high strength, wear resistance, and chemical resistance. Therefore, the support layer 101 in this embodiment is specifically an organic polymer layer, which can provide support performance while reducing the weight of the peelable metal foil, increasing the service life and performance of the peelable metal foil, and being environmentally friendly. Taking the ultra-thin peelable copper foil as an example, in this embodiment, polyamide material is exemplarily used as the composition material of the support layer 101. Since the polyamide material has the characteristics of high strength, wear resistance, and chemical resistance, and its density is about 1.15 g / cm3 , while the density of copper is 8.96 g / cm 3 , the density of polyamide is much smaller than that of copper. While it can meet the function of carrying copper, it can greatly reduce the metal waste caused by the peeling of the metal foil carrier 100, is convenient for recycling, has no toxic gas emissions, and meets the environmental protection requirements.

[0043] As a preferred solution, the metal foil carrier 100 further includes a first conductive layer 102, and the first conductive layer 102 is disposed on the first side surface.

[0044] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of the second metal foil carrier provided by the embodiment of the present invention. Specifically, the metal foil carrier 100 in this embodiment further includes a first conductive layer 102 disposed on the first side surface of the support layer 101. The first conductive layer 102 can be disposed on the first side surface by bonding, or the first conductive layer 102 can be formed on the first side surface of the support layer 101 by any one of the processes of electroless plating, physical vapor deposition, chemical vapor deposition, high-temperature evaporation plating, vacuum sputtering, electroplating, and mixed plating. Further, since the first conductive layer 102 has good electrical conductivity, by providing the first conductive layer 102, one side of the metal foil carrier 100 can be made conductive, which can meet the usage requirements of the functional layer 300 under special processes and can also meet the electroplating requirements of the functional layer 300 during the manufacturing process.

[0045] As a preferred solution, the metal foil carrier 100 further includes a heat-resistant layer 103. The support layer 101 further has a second side surface, and the heat-resistant layer 103 is disposed on the second side surface. The first side surface and the second side surface are respectively disposed on opposite sides of the support layer 101.

[0046] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of the third metal foil carrier provided by the embodiment of the present invention. Specifically, during the high-temperature pressing process of the functional layer 300 and the circuit board substrate, the support layer 101 may come into contact with the high-temperature pressing plate of the press and cause melting or deformation, thereby affecting the structural stability of the peelable metal foil, and may even cause the metal foil carrier 100 and the functional layer 300 to diffuse into each other at high temperatures and cause adhesion, making it difficult to peel the metal foil carrier 100 from the functional layer 300. Therefore, the metal foil carrier 100 in this embodiment further includes a heat-resistant layer 103, and the support layer 101 further has a second side surface opposite to the first side surface. By disposing the heat-resistant layer 103 on the second side surface of the support layer 101, during the high-temperature pressing process of the functional layer 300 and the circuit board substrate, it can be avoided that the support layer 101 comes into contact with the high-temperature pressing plate of the press and causes melting or deformation, which helps to improve the reliability of the metal foil carrier 100.

[0047] As a preferred solution, the heat-resistant layer 103 is a polyether ether ketone film.

[0048] Specifically, the heat-resistant layer 103 in this embodiment is a polyether ether ketone film, which has the advantages of good heat resistance and low cost, and can effectively prevent the support layer 101 from contacting the high-temperature pressing plate of the press and causing melting or deformation, which helps to improve the reliability of the metal foil carrier 100.

[0049] In addition, the heat-resistant layer 103 can also be an epoxy phenolic layer, a silicone layer, an inorganic zinc-rich coating, a polyimide coating, a polyurethane coating, a polytetrafluoroethylene coating, a silicone resin layer or other material layers with heat-resistant properties, and this embodiment will not elaborate too much here.

[0050] As a preferred solution, the metal foil carrier 100 further includes a second conductive layer 104, and the second conductive layer 104 is disposed between the heat-resistant layer 103 and the support layer 101.

[0051] Please refer to Figure 4 , Figure 4 FIG. is a schematic structural diagram of a fourth metal foil carrier provided by an embodiment of the present invention. Specifically, the metal foil carrier 100 in this embodiment further includes a second conductive layer 104 disposed between the heat-resistant layer 103 and the support layer 101, that is, the second conductive layer 104 is disposed on the second side surface of the support layer 101. The second conductive layer 104 can be bonded to the second side surface, or the second conductive layer 104 can be formed on the second side surface of the support layer 101 by any one of the processes of electroless plating, physical vapor deposition, chemical vapor deposition, high-temperature evaporation plating, vacuum sputtering, electroplating, and hybrid plating. Further, since the second conductive layer 104 has good electrical conductivity, by providing the second conductive layer 104, the metal foil carrier 100 forms a sandwich structure with conductive layers on both sides and the support layer 101 in the middle. Therefore, both sides of the metal foil carrier 100 can be made conductive, which can better meet the use requirements of the functional layer 300 under special processes and can also better meet the electroplating requirements of the functional layer 300 during the manufacturing process.

[0052] As a preferred solution, the bonding strength between the heat-resistant layer 103 and the second conductive layer 104 is greater than 0.6 N / cm.

[0053] It should be noted that after the functional layer 300 is hot-pressed onto the circuit board, the metal foil carrier 100 needs to be peeled off. If the bonding force between the heat-resistant layer 103 and the second conductive layer 102 in the metal foil carrier 100 is too small, the heat-resistant layer 103 and the second conductive layer 102 are likely to delaminate during the peeling process of the metal foil carrier 100, resulting in the metal foil carrier 100 not being peeled off completely, leaving more metal foil carrier 100 residues on the functional layer 300 and affecting the normal use of the functional layer 300. Therefore, in this embodiment, by defining that the bonding force between the heat-resistant layer 103 and the second conductive layer 104 is greater than 0.6 N / cm. For example, the bonding force between the heat-resistant layer 103 and the second conductive layer 104 is 0.6 N / cm, 0.65 N / cm, 0.7 N / cm, 0.75 N / cm, 0.8 N / cm, 0.85 N / cm, 0.9 N / cm, etc. This embodiment does not make specific limitations here, so as to avoid delamination between the heat-resistant layer 103 and the second conductive layer 102 during the peeling process of the metal foil carrier 100, ensure that the metal foil carrier 100 can be peeled off completely, and improve the use reliability of the peelable metal foil.

[0054] As a preferred solution, the bonding force between the first conductive layer 102 and the support layer 101 is greater than 0.6 N / cm. Further, the bonding force between the second conductive layer 104 and the support layer 101 is greater than 0.6 N / cm.

[0055] It should be noted that after the functional layer 300 is hot-pressed onto the circuit board, the metal foil carrier 100 needs to be peeled off. If the bonding force between the first conductive layer 102 and the support layer 101 in the metal foil carrier 100 is too small, during the process of peeling the metal foil carrier 100 from the functional layer 300, the first conductive layer 102 may separate from the support layer 101 and adhere to the functional layer 300, resulting in the metal foil carrier 100 not being peeled off completely and affecting the normal use of the functional layer 300. Therefore, in this embodiment, by defining that the bonding force between the first conductive layer 102 and the support layer 101 is greater than 0.6 N / cm. For example, the bonding force between the first conductive layer 102 and the support layer 101 is 0.65 N / cm, 0.7 N / cm, 0.75 N / cm, 0.8 N / cm, 0.85 N / cm, 0.9 N / cm, etc. This embodiment does not make specific limitations here, so as to avoid the first conductive layer 102 separating from the support layer 101 and adhering to the functional layer 300 during the process of peeling the metal foil carrier 100 from the functional layer 300, ensure that the separation interface is between the first conductive layer 102 and the functional layer 300, make the metal foil carrier 100 can be peeled off completely, and improve the use reliability of the peelable metal foil.

[0056] Further, if the bonding force between the second conductive layer 104 and the support layer 101 in the metal foil carrier 100 is too small, during the process of peeling the metal foil carrier 100 from the functional layer 300, the second conductive layer 104 may separate from the support layer 101, resulting in the support layer 101 and the first conductive layer 102 adhering to the functional layer 300. In this way, the metal foil carrier 100 cannot be peeled off completely, leaving more metal foil carriers 100 remaining on the functional layer 300. Therefore, in this embodiment, by defining that the bonding force between the second conductive layer 104 and the support layer 101 is greater than 0.6 N / cm. For example, the bonding force between the second conductive layer 104 and the support layer 101 is 0.65 N / cm, 0.7 N / cm, 0.75 N / cm, 0.8 N / cm, 0.85 N / cm, 0.9 N / cm, etc. This embodiment does not make specific limitations here. Thus, during the process of peeling the metal foil carrier 100 from the functional layer 300, the separation of the second conductive layer 104 from the support layer 101 can be avoided, and further the adhesion of the support layer 101 and the first conductive layer 102 to the functional layer 300 can be avoided, ensuring that the separation interface is between the metal foil carrier 100 and the functional layer 300, enabling the metal foil carrier 100 to be peeled off completely, and further improving the use reliability of the peelable metal foil.

[0057] As a preferred solution, the support layer 101 is provided with through holes, and the first conductive layer 102 is electrically connected to the second conductive layer 104 through the through holes.

[0058] It should be noted that in this embodiment, the first conductive layer 102 is electrically connected to the second conductive layer 104 through the through holes formed in the support layer 101, which can further improve the bonding force between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101, thus better avoiding the delamination of the first conductive layer 102 and the support layer 101, as well as the delamination of the second conductive layer 104 and the support layer 101 during the peeling process of the metal foil carrier 100, ensuring that the metal foil carrier 100 can be peeled off completely, and improving the use reliability of the peelable metal foil.

[0059] As a preferred solution, the diameter of the through holes first increases and then decreases from the first conductive layer 102 to the second conductive layer 104.

[0060] It should be noted that in this embodiment, the diameter of the perforation increases first and then decreases from the first conductive layer 102 to the second conductive layer 104. For example, the diameter in the middle of the perforation is the largest, and the diameters at both ends are the smallest. Thus, during the high-temperature pressing process of the functional layer 300, metal fracture inside the perforation can be avoided, ensuring the structural stability of the metal foil carrier 100 and preventing delamination between the first conductive layer 102 and the support layer 101, as well as between the second conductive layer 104 and the support layer 101 during the peeling process. In addition, while ensuring structural stability, since the diameters at both ends of the perforation are relatively small, the amount of metal used can be reduced to a certain extent, thereby reducing material waste caused after the metal foil carrier is peeled off.

[0061] As a preferred solution, the difference between the axial spacing of two adjacent perforations and the maximum aperture of the perforation is greater than 9 μm.

[0062] It should be noted that in this embodiment, by defining that the difference between the axial spacing of two adjacent perforations and the maximum aperture of the perforation is greater than 9 μm, the density and size of the perforations can be adjusted within this defined range, reducing the amount of metal used while ensuring the bonding force between the conductive layer and the support layer 101.

[0063] It can be understood that when the difference between the axial distance between two adjacent perforations and the maximum aperture of the perforation is less than or equal to 9 μm, for example, the difference is 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, etc., which is not specifically limited in this embodiment, indicating that the axial distance between two adjacent perforations is small, that is, the perforation density is large, or the maximum aperture of the perforation is large, which will result in excessive consumption of metal in the support layer 101, and serious material waste will be caused after the carrier layer is peeled off. Exemplarily, assuming that there are currently 3 support layers 101, when the maximum aperture of the perforations is equal and the bonding force between the conductive layer and the support layer 101 is ensured, the differences between the axial distance between two adjacent perforations and the maximum aperture of the perforation in the 3 support layers 101 are 4 μm, 9 μm, and 11 μm respectively. Then, compared with the support layers 101 with differences of 9 μm and 11 μm, the perforation density on the support layer 101 with a difference of 4 μm is obviously the largest, and the number of perforations in the same range is the largest. Correspondingly, the largest amount of metal is required, resulting in serious material waste after the carrier layer is peeled off; although the perforation density on the support layer 101 with a difference of 9 μm is smaller than that of the support layer 101 with a difference of 4 μm, compared with the support layer 101 with a difference of 11 μm, the number of perforations in the same range is still relatively large, and a large amount of metal is required, and the weight reduction effect is not obvious; compared with the support layers 101 with differences of 4 μm and 9 μm, the support layer 101 with a difference of 11 μm has a smaller perforation density and fewer perforations in the same range, which can greatly reduce the metal consumption and has an obvious weight reduction effect. In addition, assuming that there are currently 3 support layers 101, when the axial distance between two adjacent perforations is equal and the bonding force between the conductive layer and the support layer 101 is ensured, the differences between the axial distance between two adjacent perforations and the maximum aperture of the perforation in the 3 support layers 101 are 6 μm, 8 μm, and 12 μm respectively. Then, compared with the support layers 101 with differences of 8 μm and 12 μm, the maximum aperture of the perforations on the support layer 101 with a difference of 6 μm is obviously the largest, and correspondingly, the largest amount of metal is required, resulting in serious material waste after the carrier layer is peeled off; although the maximum aperture of the perforations on the support layer 101 with a difference of 8 μm is smaller than that of the support layer 101 with a difference of 6 μm, compared with the support layer 101 with a difference of 12 μm, the maximum aperture of its perforations is still relatively large, and a large amount of metal is required, and the weight reduction effect is not obvious; compared with the support layers 101 with differences of 6 μm and 8 μm, the support layer 101 with a difference of 12 μm has a smaller maximum aperture of the perforations, which can greatly reduce the metal consumption and has an obvious weight reduction effect.

[0064] Preferably, the difference between the axial distance between two adjacent perforations and the maximum aperture of the perforations should not be too large, such as 30μm, 38μm, 45μm, 50μm, etc. If this difference is too large, it indicates that the axial distance between two adjacent perforations is large, that is, the perforation density is small, or the maximum aperture of the perforations is small, which will result in a poor bonding force between the conductive layer and the support layer 101, thus affecting the structural stability of the metal foil carrier 100. Exemplarily, assuming that there are currently 2 support layers 101, and the maximum aperture of the perforations is equal, the differences between the axial distance between two adjacent perforations and the maximum aperture of the perforations in the 2 support layers 101 are 10μm and 30μm respectively. Then, compared with the support layer 101 with a difference of 10μm, the perforation density on the support layer 101 with a difference of 30μm is obviously very small, making it difficult to effectively avoid delamination between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101 during the peeling process of the metal foil carrier 100, and the reliability of the peelable metal foil is poor; while the perforation density on the support layer 101 with a difference of 10μm is relatively large, which can better improve the bonding force between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101, thus better avoiding delamination between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101 during the peeling process of the metal foil carrier 100, ensuring that the metal foil carrier 100 can be peeled off completely and improving the reliability of the peelable metal foil. In addition, assuming that there are currently 2 support layers 101, and the axial distance between two adjacent perforations is equal, the differences between the axial distance between two adjacent perforations and the maximum aperture of the perforations in the 2 support layers 101 are 13μm and 38μm respectively. Then, compared with the support layer 101 with a difference of 13μm, the maximum aperture of the perforations on the support layer 101 with a difference of 38μm is obviously very small, making it difficult to provide good compressive resistance during the lamination process of the functional layer 300, thus being prone to breakage, resulting in poor structural stability of the metal foil carrier 100 and making it difficult to avoid delamination between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101 during the peeling process; while the maximum aperture of the perforations on the support layer 101 with a difference of 13μm is relatively large, which can provide good compressive resistance, thus being able to avoid breakage, ensuring the structural stability of the metal foil carrier 100 and avoiding delamination between the first conductive layer 102 and the support layer 101, and between the second conductive layer 104 and the support layer 101 during the peeling process.

[0065] As a preferred solution, the difference in the coefficient of thermal expansion between the first conductive layer 102 and the support layer 101 is less than 15 PPM / °C. Further, the difference in the coefficient of thermal expansion between the second conductive layer 104 and the support layer 101 is less than 15 PPM / °C.

[0066] It should be noted that during the high-temperature pressing process of the functional layer 300 and the circuit board substrate, if the difference in the coefficient of thermal expansion between the first conductive layer 102 and the support layer 101 in the metal foil carrier 100 is too large, the materials of the two may be deformed, cracked or fatigued due to thermal stress concentration. Moreover, when the temperature changes, the elongation or contraction of the two may be asynchronous, resulting in warping deformation of the two, which affects the bonding force between the first conductive layer 102 and the support layer 101. As a result, during the high-temperature pressing process, the first conductive layer 102 is separated from the support layer 101 and bonded to the functional layer 300, making it impossible to completely peel off the metal foil carrier 100. Therefore, in this embodiment, by limiting the difference in the coefficient of thermal expansion between the first conductive layer 102 and the support layer 101 to be less than 15 PPM / °C. For example, the difference in the coefficient of thermal expansion between the first conductive layer 102 and the support layer 101 is 14 PPM / °C, 13 PPM / °C, 12 PPM / °C, 9 PPM / °C, 7 PPM / °C, 5 PPM / °C, etc. This embodiment does not make specific limitations here. Thus, during the high-temperature pressing process, it is possible to avoid the material deformation, cracking or fatigue fracture of the first conductive layer 102 and the support layer 101 due to thermal stress concentration, and it is possible to avoid the warping deformation of the two due to the asynchronous elongation or contraction of the first conductive layer 102 and the support layer 101 when the temperature changes, ensuring the stability of the bonding force between the first conductive layer 102 and the support layer 101. Therefore, it is ensured that during the high-temperature pressing process, the first conductive layer 102 will not be separated from the support layer 101 and bonded to the functional layer 300, ensuring that the separation interface is the separation of the first conductive layer 102 and the functional layer 300, enabling the metal foil carrier 100 to be completely peeled off and improving the use reliability of the peelable metal foil.

[0067] Furthermore, if the difference in the coefficient of thermal expansion between the second conductive layer 104 and the support layer 101 in the metal foil carrier 100 is too large, the materials of the two may deform, crack or experience fatigue fracture due to thermal stress concentration. Moreover, when the temperature changes, the elongation or contraction of the two may not be synchronized, resulting in warping deformation of the two, which affects the bonding force between the second conductive layer 104 and the support layer 101. As a result, during the high-temperature lamination process, the second conductive layer 104 separates from the support layer 101, causing the support layer 101 and the first conductive layer 102 to adhere to the functional layer 300, making it impossible to completely peel off the metal foil carrier 100. Therefore, in this embodiment, by limiting the difference in the coefficient of thermal expansion between the second conductive layer 104 and the support layer 101 to be less than 15 PPM / °C. For example, the difference in the coefficient of thermal expansion between the second conductive layer 104 and the support layer 101 is 14 PPM / °C, 13 PPM / °C, 12 PPM / °C, 9 PPM / °C, 7 PPM / °C, 5 PPM / °C, etc. This embodiment does not make specific limitations here, so as to avoid material deformation, cracking or fatigue fracture of the second conductive layer 104 and the support layer 101 due to thermal stress concentration during the high-temperature lamination process, and to avoid warping deformation of the two due to the unsynchronized elongation or contraction of the second conductive layer 104 and the support layer 101 when the temperature changes, ensuring the stability of the bonding force between the second conductive layer 104 and the support layer 101. Thus, it is ensured that during the high-temperature lamination process, the second conductive layer 104 does not separate from the support layer 101, causing the support layer 101 and the first conductive layer 102 to adhere to the functional layer 300, ensuring that the separation interface is between the metal foil carrier 100 and the functional layer 300, enabling the metal foil carrier 100 to be completely peeled off, and improving the use reliability of the peelable metal foil.

[0068] As a preferred solution, the material of the first conductive layer 102 and / or the second conductive layer 104 includes at least one of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium and / or an alloy of at least one of them; or, the material of the first conductive layer 102 and / or the second conductive layer 104 includes at least one of graphite, graphene, conductive polymer, carbon nanotube, conductive polymer.

[0069] It should be noted that there are two implementable technical solutions in this embodiment, that is, the materials of the first conductive layer 102 and the second conductive layer 104 include at least one of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium and / or an alloy of at least one of them; or, the materials of the first conductive layer 102 and the second conductive layer 104 include at least one of graphite, graphene, conductive polymer, carbon nanotube, conductive polymer; and, the material of the first conductive layer 102 or the second conductive layer 104 includes at least one of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium and / or an alloy of at least one of them; or, the material of the first conductive layer 102 or the second conductive layer 104 includes at least one of graphite, graphene, conductive polymer, carbon nanotube, conductive polymer.

[0070] Specifically, in this embodiment, the first conductive layer 102 and / or the second conductive layer 104 are made of metals with good conductivity and low resistivity, including single-metal conductive layers and / or alloy conductive layers; among them, the single-metal conductive layer is made of any one of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium, and the alloy conductive layer is made of any two or more of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium, or can also be made of any two or more of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium and other materials mixed. In addition, in this embodiment, the first conductive layer 102 and / or the second conductive layer 104 can also be made of at least one of graphite, graphene, conductive polymer, carbon nanotube, conductive polymer.

[0071] In this embodiment, since the materials of the first conductive layer 102 and / or the second conductive layer 104 include at least one of copper, aluminum, silver, gold, nickel, iron, tin, molybdenum, zirconium, chromium and / or an alloy of at least one of them; or, the materials of the first conductive layer 102 and / or the second conductive layer 104 include at least one of graphite, graphene, conductive polymer, carbon nanotube, conductive polymer, it can provide good electrical conductivity for the metal foil carrier 100 to meet the usage requirements of the functional layer 300 under special processes, and can also better meet the electroplating requirements of the functional layer 300 during the manufacturing process.

[0072] As a preferred solution, the thickness of the heat-resistant layer 103 is 20 nm to 15 μm.

[0073] It should be noted that the thickness of the heat-resistant layer 103 affects its performance. Generally speaking, when the thickness of the heat-resistant layer 103 is small, its heat insulation performance is poor. Therefore, during the high-temperature lamination process of the functional layer 300 and the circuit board substrate, the too-thin heat-resistant layer 103 cannot avoid the melting or deformation caused by the contact between the support layer 101 and the high-temperature pressing plate of the press, resulting in low reliability of the metal foil carrier 100. When the thickness of the heat-resistant layer 103 is large, although its heat insulation performance is good, it will cause a decline in mechanical properties such as adhesion, resulting in cracks and peeling of the heat-resistant layer 103. Moreover, too thick a heat-resistant layer 103 will increase production costs. Therefore, in this embodiment, the thickness of the heat-resistant layer 103 is limited to 20 nm to 15 μm. For example, the thickness of the heat-resistant layer 103 is 20 nm, 50 nm, 100 nm, 500 nm, 700 nm, 1 μm, 3 μm, 7 μm, 11 μm, 15 μm, etc. This embodiment does not make specific limitations here, so as to ensure that the heat-resistant layer 103 has good heat insulation performance while not causing a decline in mechanical properties due to excessive thickness, avoiding cracks and peeling, and helping to improve the use reliability of the metal foil carrier 100.

[0074] As a preferred solution, the thickness of the support layer 101 is 10 μm to 100 μm.

[0075] It should be noted that since the support layer 101 is used to provide support strength for the functional layer 300, it needs to have a certain thickness to play a stable supporting role. In this embodiment, by setting the thickness of the support layer 101 to 10 μm to 100 μm, for example, the thickness of the support layer 101 is 10 μm, 15 μm, 24 μm, 37 μm, 48 μm, 65 μm, 78 μm, 100 μm, etc. This embodiment does not make specific limitations here, so that the support layer 101 is not too thin to ensure that its thickness is sufficient to provide support strength for the peelable metal foil as the support layer 101, and it is also convenient for the production and manufacture of the metal foil carrier 100, because too thin a support layer 101 is easy to adhere to the surface of the conveyor roller, resulting in a large number of defects such as wrinkles and fine lines. At the same time, it is not too thick to avoid excessive volume and weight of the peelable metal foil. Preferably, the thickness of the support layer 101 in this embodiment is set to 18 μm, so as to ensure good support performance and electrical conductivity, and at the same time meet the high-precision requirements during circuit board processing.

[0076] Please refer to Figure 5 , Figure 5It is a schematic structural diagram of the peelable metal foil in the embodiment of the present utility model. The second aspect of the embodiment of the present utility model provides a peelable metal foil, which includes a functional layer 300, a release layer 200, and a metal foil carrier 100 as in any embodiment of the first aspect. The functional layer 300 is connected to the first side of the support layer 101 in the metal foil carrier 100 through the release layer 200.

[0077] It should be noted that the functional layer 300 functions as an electrical conductor. In this embodiment, the functional layer 300 is preferably a thin copper layer. Of course, the material of the functional layer 300 may also include at least one of the metal elements such as copper, aluminum, zinc, nickel, and silver. This embodiment will not elaborate too much here. Preferably, the thickness of the thin copper layer in this embodiment is 1 - 5 μm, for example, it can be 1 μm, 1.6 μm, 2.3 μm, 3.5 μm, 4 μm, 5 μm, etc. This embodiment does not make specific limitations here.

[0078] In practical applications, for example, when applied in the field of circuit boards, the functional layer 300 is thermally pressed and bonded to the substrate of the circuit board. For example, when applied in the field of electronic material production, the functional layer 300 made of copper material is combined with other composite materials to manufacture copper - clad laminates, flexible copper - clad laminates, or used as the production raw material of coated copper foil. For example, when applied in the field of batteries, the functional layer 300 made of copper material serves as the negative electrode material (negative current collector) of the battery, and it is thermally pressed and bonded to the negative active material in the negative electrode material. The functional layer 300 made of aluminum material serves as the positive electrode material (positive current collector) of the battery.

[0079] The function of the release layer 200 is to achieve the separation of the metal foil carrier 100 and the functional layer 300 through peeling. At the same time, due to the existence of the release layer 200, it can block the metal migration between the functional layer 300 and the metal foil carrier 100. Moreover, the release layer 200 can cover or fill the uneven surface of the metal foil carrier 100, making the functional layer 300 formed on the other surface of the release layer 200 more flat, uniform, and dense, reducing the occurrence of pinholes, and thus being beneficial to the subsequent circuit production.

[0080] Materials of the release layer 200: It includes metals, such as any one or more of copper, nickel, silicon, molybdenum, graphite, titanium, and niobium, and there may also be a certain amount of copper; or, non-metals, such as organic polymer materials, or a non-silicon release agent release layer, a silicone oil release layer, or a nitrogen release layer. The release layer can be formed after the release agent is coated and dried. The release agent can include solvents such as HDPE (high-density polyethylene) and PMA (propylene glycol methyl ether acetate); when the above two release agents are used, the mass ratio of HDPE:PMA is preferably (1-5):7. In some other embodiments, the release agent can include a fluorine-based release agent and a solvent; wherein, the volume ratio of the fluorine-based release agent to the solvent is preferably (5-30):1; the types of the above solvents are not particularly limited, and conventional release agent solvents in the art can be selected, such as methyl ethyl ketone, which do not constitute a limitation to the present utility model.

[0081] Preferably, in this embodiment, the thickness of the release layer 200 is 20nm to 900nm, for example, it can be 20nm, 45nm, 125nm, 245nm, 500nm, 675nm, 800nm, 900nm, etc., and this embodiment does not make specific limitations here. In addition, the release layer 200 in this embodiment can be processed on the metal foil carrier 100 by means such as sputtering and evaporation coating.

[0082] In the specific implementation process, the metal foil carrier 100 is separated from the functional layer 300 in a peelable and removable manner or a non-peelable and non-removable manner. When the metal foil carrier 100 is removed in a non-peelable and non-removable manner, the non-peelable methods are such as laser etching, chemical etching, grinding, plasma removal, etc. When the metal foil carrier 100 is removed by peeling, the peeling methods are such as manually peeling it off directly or removing it by means of mechanical equipment. Since in this embodiment, the density of the support layer 101 in the metal foil carrier 100 is less than the density of the metal, the amount of metal used can be significantly reduced under the same thickness, and thus the material waste caused after the metal foil carrier 100 is peeled off can be reduced.

[0083] The third aspect of the embodiment of the present utility model provides a circuit board (not shown in the figure), and the circuit board includes a peelable metal foil as in the second aspect.

[0084] The beneficial effects of the metal foil carrier 100, the peelable metal foil, and the circuit board provided by the embodiment of the present utility model are as follows:

[0085] Since the density of the support layer 101 in the metal foil carrier 100 is less than the density of the metal, the amount of metal used can be significantly reduced under the same thickness, and thus the material waste caused after the metal foil carrier 100 is peeled off can be reduced, effectively reducing the use and recycling costs and meeting the environmental protection requirements.

[0086] The above are the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present utility model.

Claims

1. A metal foil carrier, characterized in that: The metal foil carrier includes a support layer, the support layer is provided with a first side for connecting to the functional layer, and the density of the support layer is less than the density of the metal; the support layer includes an organic layer or an inorganic layer; or, the support layer includes at least two layers, at least the two layers include an organic layer and / or an inorganic layer.

2. The metal foil carrier according to claim 1, characterized in that The metal foil carrier also includes a first conductive layer disposed on the first side.

3. The metal foil carrier according to claim 2, characterized in that The metal foil carrier further includes a heat-resistant layer. The support layer further includes a second side surface. The heat-resistant layer is disposed on the second side surface. The first side surface and the second side surface are respectively disposed on two opposite sides of the support layer.

4. The metal foil carrier according to claim 3, characterized in that The heat-resistant layer is a polyetheretherketone film.

5. The metal foil carrier according to claim 3, characterized in that: The metal foil carrier further includes a second conductive layer disposed between the heat-resistant layer and the support layer.

6. The metal foil carrier according to claim 5, characterized in that The bonding force between the heat-resistant layer and the second conductive layer is greater than 0.6 N / cm; and / or, The bonding force between the first conductive layer and the support layer is greater than 0.6 N / cm; and / or, The bonding force between the second conductive layer and the support layer is greater than 0.6 N / cm.

7. The metal foil carrier according to claim 5, characterized in that The support layer is provided with a through hole, and the first conductive layer is electrically connected to the second conductive layer through the through hole.

8. The metal foil carrier according to claim 7, characterized in that The diameter of the through hole increases first and then decreases from the first conductive layer to the second conductive layer.

9. The metal foil carrier according to claim 7, characterized in that: The difference between the axis distance between two adjacent through holes and the maximum aperture of the through holes is greater than 9 μm.

10. The metal foil carrier according to claim 5, characterized in that The difference in thermal expansion coefficient between the first conductive layer and the support layer is less than 15 PPM / °C; and / or the difference in thermal expansion coefficient between the second conductive layer and the support layer is less than 15 PPM / °C.

11. The metal foil carrier according to claim 3, characterized in that The thickness of the heat-resistant layer is 20 nm to 15 μm.

12. The metal foil carrier according to any one of claims 1 to 11, characterized in that: The thickness of the support layer is 10 μm to 100 μm.

13. A peelable metal foil, characterized in that: The peelable metal foil comprises a functional layer, a peeling layer and the metal foil carrier according to any one of claims 1 to 12, wherein the functional layer is connected to the first side surface of the support layer in the metal foil carrier through the peeling layer.

14. A circuit board, characterized in that: The circuit board includes the peelable metal foil as claimed in claim 13.

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